The purpose of the invention is to provide a porous polyolefin membrane consistent with a simple composition that may be characterized by a small pore diameter and a high porosity by simplifying the manufacturing process to facilitate uniform dispersion of the components. Means to achieve the purpose—A porous polyolefin membrane is formed by melting and kneading a specific resin (C) which composition containing a polyolefin resin consisting of a crystalline polypropylene (A) and a propylene-α-olefin copolymer (B), dispersed in said crystalline polypropylene (A), to obtain a film-shaped melt, and forming a membrane from the said melt with specific conditions, followed by stretching of said membrane at least in one direction, which contains continuous pores in the region consisting of said copolymer (B).

1. Field of the Invention
The present invention relates to porous polyolefin membranes. More specifically, it relates to porous polyolefin membranes useful for applications including separation membranes or separators for galvanic cells.
2. Description of the Related Art
Porous plastic membranes have been used in a number of applications including separation membranes for filtration in medicine and industry, separators in galvanic cells and electrolytic capacitors, linings for paper diapers and other hygiene products, and building materials such as construction film and roofing base materials. In particular, porous polyolefin membranes are useful in applications in which the membranes come into contact with organic solvents or alkali or acidic solutions owing to their resistance to these substances.
Known manufacturing processes for porous polyolefin membranes include the following:    (a) Wherein a film consisting of a polyolefin combined with an inorganic filler, such as silica or talc, or an organic filler, such as nylon or polyethylene terephthalate, which are insoluble in the polyolefin, is stretched at least in one direction to form pores at the interfaces between the matrix polymer and filler ("multicomponent stretching" hereinafter).    (b) Wherein a crystalline polypropylene film manufactured at a high draft ratio, subsequently heat-treated as necessary, is stretched at least in one direction to form fibrils between lamellar crystallites, yielding a porous film ("single-component stretching" hereinafter).    (c) Wherein a film obtained by the formation of a mixture of a polyolefin resin with an organic liquid or an inorganic filler undergoes extraction of said organic liquid or inorganic filler, with stretching before or after said extraction, as necessary ("mixture extraction" hereinafter).
The multi-component stretching process, (a) above, may involve the addition of an inorganic filler or organic filler. A substantial quantity of inorganic filler is required, which may impair the properties, pliability, and acid/alkali resistance of the matrix polyolefin. An organic filler not only impairs the properties and pliability of the polyolefin but also presents difficulties in ensuring a fine dispersion in the matrix polymer, thus making it difficult to obtain films with a fine pore diameter or a high porosity.
The single-component extraction process, (b) above, involves film formation at a high draft ratio, prolonged heat treatment in a separate step, and multistage stretching under specific conditions. The sophistication inherent in the process necessitates a long manufacturing interval and suffers from low productivity. Additional problems include difficulty in obtaining films with a high porosity, which is intrinsic to the technique of fibril formation between lamellar crystallites, and low tear resistance of the membrane obtained as a result of stretching a highly oriented crystalline sheet.
The mixture extraction process, (c) above, represents a comparatively complicated method involving an extraction step wherein said organic liquid in the sheet is extracted with an organic solvent, or said inorganic filler with an alkaline solvent, followed by a washing and drying step. The organic liquid, if used, accounts for 40–60% by weight of the sheet, which retards the film forming process and renders stretching difficult. Moreover, the organic liquid tends to coat the rollers and other machine parts of the manufacturing process leading to reduced productivity.
Meanwhile, a porous membrane involving a simple manufacturing process thereof has been disclosed, wherein said membrane comprises of a component A consisting of an ethylene-propylene block copolymer, a component B consisting of a homopolymer or a random copolymer of propylene, and a component C consisting of a low molecular weight polypropylene, with the addition as necessary of a component D consisting of calcium carbonate or a component E consisting of a nucleation agent for beta spherulites (see e.g. Reference 1). In addition, a porous film has been disclosed consisting of a crystalline polyolefin resin composed of an ethylene-propylene block copolymer solely or, as necessary, in combination with polypropylene or polyethylene, to which a mineral oil or an ester compound with a boiling point up to 100° C. has been incorporated (see e.g. Reference 2).
These methods intend to improve the poor porosity and air permeability of pure ethylene-propylene block copolymer films by using additional components. However, a multicomponent system requires uniform distribution of those components to generate a uniform porous film. Furthermore, the pores thus formed in the membrane tend to consist of large diameters, which lead to difficulties in obtaining thin membranes, or membranes with a high porosity or high air/moisture permeability. Therefore, porous membranes manufactured according to these methods are not suitable for use as battery separators which require fine pores, or precision filters which require high porosity and air permeability.
Reference 1:
U.S. Pat. No. 5,176,953
Reference 2:
JP 8-208862 A (1996)
Problems Addressed by the Invention
The purpose of the present invention is, therefore, to solve the problems mentioned above in relation to conventional porous polyolefin membranes. More specifically, its purpose is to provide a porous polyolefin membrane having a simple resin composition, which facilitates uniform distribution of the components during the manufacturing process, resulting in the yield of fine pores and a high porosity.
Means to Solution of the Problems
The inventors have found that the problems mentioned above can be solved by the manufacture of a porous polyolefin membrane formed by melting and kneading a specific resin (C) which composition containing a polyolefin resin consisting of a crystalline polypropylene (A) and a propylene-α-olefin copolymer (B), dispersed in said crystalline polypropylene (A), to obtain a film-shaped melt, and forming a membrane from said melt in specific conditions, followed by stretching of the said membrane at least in one direction, which contains continuous pores in the region consisting of said copolymer (B). The present invention is based on this finding. "Continuous pores", as mentioned in this specification, describes pores formed in a continuous manner in the copolymer (B) region, which eventually connects the two surfaces of the porous membrane.


According to an aspect of the invention, there is provided a method of recording an image, including irradiating a CO2 laser having a wavelength of from 9 to 11 μm onto a recording material in which a recording layer and a protective layer are provided on a support in this order, wherein the recording layer includes at least microcapsules encapsulating a basic dye precursor, and the protective layer includes a binder.

1. Field of the Invention
The present invention relates to an image recording method, and more particularly to a recording method of recording an image in a recording material that forms a color by irradiation of a laser beam.
2. Description of the Related Art
On beverage cans, beverage containers, food containers, medicine containers, cosmetics containers, packaging materials, electronic components, electric parts, automotive components and the like (hereinafter referred to as "containers"), a manufacturing lot number, manufacturing date, model, name of manufacturer and the like are, for example, marked by characters, symbols, marks, patterns, barcodes or the like (hereinafter referred to as "marks").
As marking methods, a method of directly printing a colored printing ink on containers by pad printing, screen printing, an ink jet method or the like, and a method of attaching labels having marks printed thereon are used. In the direct printing method, however, printing may be difficult depending on the shape of the container to be printed on, and in the method of attaching printed labels, a wide variety of labels must be prepared for respective types of marks.
To solve these problems, recently, laser marking methods have come to be used in which a laser marking layer including a color former and a developer is provided on containers, and a laser beam is irradiated to the layer to cause a chemical reaction to form a color (see, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 7-257042, 2002-347344, and 9-175035). This method is superior in productivity to the previous methods and thus is suitable for forming marks on containers.
In the laser marking method, however, when printing a label coated with a laser marking layer, the label may be colored by the solvent of the printing ink, or when a container to which a label is attached is heated for sterilization, a color may be formed. As a result, if a laser is irradiated to form a color after this, clear marks may not be obtained, so that the commercial value is reduced.


An operation control device is provided in an electro-developing type camera using a recording medium which electronically develops an image formed by a photographing optical system. During a reading operation, in which the image recorded in the electro-developing recording medium is being read, if a recording operation is set by operation of a main switch, an enforced recording operation is started. During the enforced recording operation, pixel signals of one horizontal scanning line of the image are read through a line sensor. Then, a shutter is closed, a light source is turned OFF, and a scanning mechanism is withdrawn to a position at which the scanning mechanism does not interfere with the optical path of the photographing optical system. If a recording medium installed in the camera has not been recorded upon, a recording operation is started and an image is recorded in the new recording medium.

1. Field of the Invention
The present invention relates to a camera using a recording medium in which an object image obtained through a photographing optical system is electronically developed, and more particularly, to a device controlling a recording operation in which the image is recorded in the recording medium.
2. Description of the Related Art
Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 5-2280 and U.S. Pat. No. 5,424,156, there is a known photographic material which is directly electronically developed so that the developed visible image can be immediately obtained. In this specification, such a recording medium is referred to as an electro-developing recording material, and an electronic still camera using the electro-developing recording material is referred to as an electro-developing type camera.
In the electro-developing type camera, a reading operation, in which an image recorded in the electro-developing recording medium is read therefrom, takes a relatively long time, for example, several tens of seconds. Therefore, if the photographer tries to take a next photograph during the reading operation of the previous photograph taken, the next photograph cannot be taken until the reading operation is completed. As a result, a photo opportunity may be missed.

Device for controlling operation of electro-developing type camera


A carrier for electrophotography has carrier particles. Each carrier particle has a carrier core and a silicone resin coat layer that covers the carrier core. The carrier particle has silicon atoms and carrier atoms on its surface in the ratio that satisfies the condition of Si/C=0.1 to 2.0 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy, and from 0.1% by number to 5% by number of metal atoms are present on the carrier particle surface. Additionally, there is a two-component developer for developing electrostatic images which consists of a toner and the carrier. An image forming method in which the two-component developer having the toner and the carrier is transported to a developing zone which is defined by a latent image carried on a latent image bearing member to develop the latent image. A voltage is applied to the developer to direct the toner from the latent image bearing member to a member carrying the developer. A second voltage directs the toner from the developer toward the latent image and a third voltage developer the latent image using the toner of the two-component developer.

1. Field of the Invention
The present invention relates to a carrier for electrophotography which composes a two-component type developer used to develop an electrostatic image in electrophotography, electrostatic recording or electrostatic printing. It also relates to a two-component type developer making use of the carrier, and an image forming method carried out using the two-component type developer.
2. Related Background Art
It is conventionally known to form an image on the surface of a photoconductive material by an electrostatic means.
A large number of methods are known as electro-photography, as disclosed in U.S. Pat. No. 2,297,691 Japanese Patent Publications No. 42-23910 and No. 43-24748 and so forth. In general, an electrostatic latent image is formed on a photosensitive member, utilizing a photoconductive material and according to various means, and subsequently a very finely divided electrodetective material called a toner is made to adhere to the latent image to form a toner image corresponding to the electrostatic latent image.
Next, the toner image is transferred to an image holding medium such as paper if necessary, followed by fixing by the action of heat, pressure, or solvent vapor. A copy is thus obtained. When the process comprises a toner-image transfer step, the process is usually provided with the step of removing the toner remaining on the photosensitive member.
As developing methods by which the electrostatic latent image is formed into a visible image by the use of a toner, known methods can be exemplified by the powder cloud development as disclosed in U.S. Pat. No. 2,221,776, the cascade development as disclosed in U.S. Pat. No. 2,618,552, the magnetic brush development as disclosed in U.S. Pat. No. 2,874,063, and the method in which a conductive magnetic toner is used, as disclosed in U.S. Pat. No. 3,909,258, as well as what is called the J/B development as disclosed in Japanese Patent Application Laid-open No. 62-63970, in which a bias electric field comprised of an AC component and a DC component is applied across a developer carrying member (a developing sleeve) and a photoconductive layer to carry out development.
Among these, the magnetic brush development can be noted as a representative process. In this process, magnetic particles such as steel powder or ferrite powder are used as a carrier, and a developer comprised of a toner and such a magnetic carrier is held with a magnet so that the developer is arranged in the form of a brush by the action of a magnetic field of the magnet. The magnetic brush thus formed is brought into contact with the electrostatic latent image surface on a photoconductive layer, whereupon only the toner is attracted toward the electrostatic latent image from the brush to carry out development.
The carrier that composes such a two-component type developer used in these development processes can be roughly grouped into a conductive carrier and an insulative carrier. The conductive carrier is usually comprised of oxidized or unoxidized iron powder. A developer composed of this iron powder carrier, however, has the problems that the triboelectric chargeability to a toner is unstable and also that fog may be generated on a visible image formed using the developer. More specifically, as the developer is used, toner particles adhere to and accumulate (spent toner) on the surfaces of the iron powder carrier particles, so that the electrical resistance of carrier particles increases to lower bias currents, and also to make the triboelectric chargeability unstable, resulting in a lowering of the image density of a visible image formed and an increase of fog. Thus, when copies are continuously taken by an electrophotographic copying machine using the developer containing the iron powder carrier, the developer may deteriorate upon copying several times and hence it becomes necessary to change the developer at an early stage, resulting in a high cost after all.
The insulative carrier is commonly typified by a carrier comprising carrier core particles comprised of a ferromagnetic material such as iron, nickel or ferrite whose surfaces are uniformly coated with an insulating resin. A developer that employs this carrier may cause little the melt-adhesion of toner particles to the carrier surfaces, compared with the case of the conductive carrier, and at the same time the triboelectric chargeability of a carrier to a toner can be controlled with ease. Hence, the developer has the advantage that it is suitable particularly for high-speed electrophotographic copying machines in view of its superior durability and long lifetime.
There are various performances required for the insulative carrier. Particularly important performances can be set out as proper chargeability, impact resistance, wear resistance, a good adhesion between cores and coating materials, and uniformity in charge distribution.
Taking account of the above required performances, insulative carriers hitherto used still leave room for improvements, and no perfect carrier is known at present. For example, use of an acrylic resin as a coating material for carriers is disclosed in Japanese Patent Applications Laid-open No. 47-13954 and No. 60-208765. In particular, its molecular weight configuration is disclosed in Japanese Patent Application Laid-open No. 60-208767, and it is known to constantly control molecular weights so that the chargeability of coated carriers can be stabilized. However, making a coating resin adhere to carrier cores tends to be affected by conditions set in apparatus and environments where the carrier cores are coated, in particular, by humidity. Even if these have been severely controlled, no satisfactory measures are available for making the resin stably adhere to cores to achieve sufficient chargeability and durability. This is the present situation of the matter.
Meanwhile, in order to prevent carrier spent such as melt-adhesion of toner, it is proposed to use as a coating material a resin having a small surface energy so as to improve durability, and the resin having a small surface energy is exemplified by silicone resin.
The silicone resin is advantageous in that it has not only a low surface tension but also a high water repellency. On the other hand, the silicone resin is problematic in that it has so poor an adhesion that coat layers formed tend to separate.
In order to overcome such a problem, proposals are made as exemplified by a method in which a resin-modified silicone resin is used (Japanese Patent Application Laid-open No. 55-127569), a method in which vinyl silane is incorporated to cause it to react with other resin (Japanese Patent Application Laid-open No. 56-32149), a method in which a mixture of a trialkoxysilane and ethyl cellulose is used (U.S. Pat. No. 3,840,464) and a method in which a mixture of an organosilicone terpolymer and a polyphenylene resin is used (U.S. Pat. No. 3,849,127). There, however, have been the problems that a high temperature of 300.degree. C. or above is required to form its coat layers, and the silicone resin has so poor a compatibility with other resins that the coating layers become non-uniform and no expected performance can be obtained. It is also proposed to prepare coat layers at a relatively low curing temperature (Japanese Patent Application Laid-open No. 55-127569). Such coat layers, however, tend to wear because of their unsatisfactory adhesion and unsatisfactory toughness. For example, in the course of strong and long-term agitation of developer in a developing assembly of a high-speed copying machine, where carrier particles collide against the inner wall of the developing assembly and the surface of a photosensitive member, the silicone resin coat layers wear and separate to cause a change in triboelectric charging from the charging between toner and silicone resin to the charging between toner and carrier cores, so that the quantity of charges of the developer can not be kept constant, causing a deterioration of image quality.
In recent years, a rapid progress is being made from monochromatic copying to full-color copying, and researches are made on two-color copying machines or full-color copying machines, which have been already put into practical use. For example, Journal of Electrophotographic Society, Vol. 22, No. 1, pp. 7-16, (1983) and Journal of Electrophotographic Society, Vol. 25, No. 1, p.52 (1986) make reports relating to color reproduction and gradation reproduction.
Images formed by full-color electrophotography presently put into practical use, however, are not necessarily satisfactory for those who are accustomed to seeing color pictures that are by no means immediately compared with the actual object or original and also processed more beautifully than the actual object or original, as in television pictures, photographs and color prints.
In full-color electrophotography, color images are commonly formed using color toners of yellow, magenta and cyan three colors to reproduce all colors.
Its process comprises the step of forming an electrostatic latent image on a photoconductive layer through a color-separating light-transmitting filter having the relation of complementary color to the color of a toner, followed by developing and transfer steps, through which a toner image is held on an image holding medium. These steps are repeated several times to superimpose toner images on the same medium while making registration, followed by fixing carried out once to obtain a final full-color image.
In general, in the case of development carried out using the developer of what is called a two-component system comprised of a toner and a carrier, the toner is electrostatically charged to the desired charge quantity and charge polarity by its friction with the carrier, and the electrostatic attraction force produced is utilized to develop electrostatic images. Accordingly, in order to obtain good visible images, the triboelectric chargeability of toner that mainly depends on the relation with the carrier must be kept good.
It is also an important point how the carrier is prevented from deterioration in long-term use. After copies have been taken for a long term, the carrier deteriorates because of deposits formed thereon and changes in properties of its particle surfaces, so that its ability to provide charges to the toner becomes weak to cause toner scatter and faulty images such as fog.
Nowadays, to cope with such problems, a variety of researches are made, e.g, investigations are made on carrier core materials and carrier coat materials, coating weights are made optimum, charge control agents and fluidity-providing agents to be added to toners are studied, and also binders serving as base materials are improved, all of which are made so that a superior triboelectric chargeability can be achieved in the materials that compose developers.
For example, as techniques to add a charging auxiliary such as chargeable fine particles to the toner, Japanese Patent Publication No. 52-32256 and Japanese Patent Application Laid-open No. 56-64352 disclose adding a resin powder having a polarity reverse to the toner, and Japanese Patent Application Laid-open No. 61-160760 discloses adding a fluorine-containing compound, which are added to developers so as to achieve a stable triboelectric chargeability. Nowadays, many charging auxiliaries are also being advanced.
Various measures are also taken as methods for adding such a charging auxiliary. For example, it is common to use a method in which electrostatic attraction force or van der Waals force, acting between toner particles and the charging auxiliary, is utilized to cause the latter to adhere to the toner particle surfaces, where a stirrer, a mixer or the like is used. In such a method, however, it is not easy to uniformly disperse the additive on the toner particle surfaces, and also additive particles not adhering to toner particles may form agglomerates to make it difficult to prevent the presence of additives brought into what is called a free state. This tends to more frequently occur with an increase in specific electrical resistance of the charging auxiliary and with a decrease in particle diameter. In such a case, an influence on the developer may come therefrom. For example, the toner comes to have an insufficient quantity of triboelectricity, resulting in non-uniform image densities and images with much fog.
The above method also have the disadvantage that the content of the charging auxiliary changes when copies are continuously taken, to make it impossible to keep image quality at the initial stage.
As another method for its addition, there is a method in which the charging auxiliary is previously added together with a binder resin and a colorant when toners are produced. However, the amount of the charging auxiliary added or the dispersion thereof on the toner particle surfaces can not be controlled with ease since charge control agents can not be made uniform with ease and also since what substantially contribute to charging performance are charging auxiliaries and charge control agents present in the vicinity of toner particle surfaces and those present inside the particles do not contribute to the charging performance. The quantity of triboelectricity is unstable also in toners obtained by such a method. Thus, as previously stated, under existing circumstances, those having a well satisfactory quality have not been available only if the charging auxiliary is used, like the case when those satisfying developer performances can not be obtained with ease.
Moreover, in recent years, there is an increasing commercial demand for making copying machines achieve greater miniturazation and making images have a higher quality. In the present technical field, it is attempted to make toner particle diameter smaller so that a color image can be formed in a high image quality. Making smaller the particle diameters of toner particles results in an increase in the surface area per unit weight, tending to bring about an excessively large quantity of triboelectricity of the toner. This is accompanied with a possibility of the insufficiency of image density or the deterioration of durability or running performance. In addition, because of the large quantity of triboelectricity, toner particles may strongly adhere to one another to cause a decrease in fluidity, bringing about a problem in the stability of toner feeding and the providing of triboelectricity to the toner.
In the case of color toners, they contain no conductive materials such as magnetic materials and carbon black, and hence have no portions from which charges are leaked to commonly tend to have a larger quantity of triboelectricity. This tendency is more remarkable when polyester type binders having a high charging performance is used.
In particular, color toners are strongly desired to have performances as shown below.
(1) Fixed toners are required to nearly come into a substantially completely molten state to the extent that the forms of toner particles can not be recognized, so as for their color reproduction not to be hindered because of irregular reflection upon exposure to light.
(2) Color toners must have a transparency not to obstruct the toner layer having a different color tone that lies beneath an upper layer thereof.
(3) The respective constituent toners must have well-balanced hues and spectral reflection properties, and sufficient chroma.
From such viewpoints, studies are made on many binder resins. However, none of toners that satisfy all of the above performances have brought out. Nowadays, in the present technical field, resins of a polyester type are widely used as binder resins for color toners. Toners comprised of a polyester resin, however, commonly tend to be affected by temperature and humidity, and tend to cause problems of an excessive charge quantity in an environment of low humidity and an insufficient charge quantity in an environment of high humidity.
Moreover, when some additives are added for the purpose of overcoming such disadvantages, carrier contamination may come into question. This inhibits charging performance of carriers to cause a decrease in charge quantity and cause image fog and toner scatter. Hence, it is sought to design carriers having a high contamination resistance to the additives. Accordingly, as a matter of course, carriers must be so designed as to have a good charging performance, and it is of urgent to make advancement of color toners that can have stable charges over a wide range of environments and also to design carriers for accomplishing color developers having a lifetime long enough to maintain good images over a long period of time as a role of developers.
Meanwhile, in the aforesaid development of electrostatic latent images, a toner with a fine particle diameter is blended with a carrier formed of relatively large particles and is used as a developer for electrophotography. The composition of both the toner and the carrier is selected so that as a result of their mutual contact friction the toner can have a polarity reverse to the charges present on the photoconductive layer. As a result of contact friction between the both, the carrier further electrostatically attracts the toner to its particle surfaces to transport the toner as a developer through a developing assembly and also feed the toner onto the photoconductive layer.
When, however, copies are continuously taken on a large number of copy sheets by an electrophotographic copying apparatus using such a two-component type developer, although sharp images with a good image quality can be obtained at the initial stage, edge effect with much fog may seriously occur after copies have been taken on several tens of thousands of sheets, resulting in images having poor gradation and sharpness.
In color copying carried out using toners with chromatic colors, continuous gradation is an important factor that influences image quality, and the edge effect that stresses only margins of images, occurring after copies have been taken on a large number of copy sheets, greatly damages the gradation of images. For example, quasi-contours due to the edge effect are formed in the vicinity of actual contours, resulting in a loss of reproducibility including color reproducibility in color copying. Image area used in conventional black and white copying is 10% or less and images are almost held by line images as in letters, documents, reports and so forth. On the other hand, in the case of color copying, image area is 20% at least, and images are held by gradational solid images at a reasonable frequency or occupancy as in photographs, catalogues, maps, pictures and so on.
When copies are continuously taken using such originals having a large image area, reproductions with a high image density can be obtained at the initial stage in usual instances, but the feeding of toner to the two-component type developer may become insufficient with time to cause a decrease in density, or the toner being fed and the carrier may mix in the state of charge insufficiency to cause fog or cause a local increase or decrease in toner concentration (which indicates toner-carrier mixing ratio) on the developing sleeve, tending to result in blurred images or non-uniform image density. This tendency becomes more noticeable when the toner has a smaller particle diameter.
Such under-development and fog are presumed to be caused by an excessively low toner content (i.e., toner concentration) in developer or a poor rise for rapid triboelectric charging between the toner being fed and the carrier contained in the two-component type developer, where any uncontrollable, insufficiently charged toner thereby produced participates in development. It is essential for color developers to have the ability to always output images with a good image quality in the continuous copying of originals having a large image area. To deal with originals having a large image area and requiring a very large toner consumption, measures hitherto taken have more relied on improvements of developing apparatus than improvements of developers themselves. That is, it has been attempted to increase the peripheral speed of a developing sleeve or make a developing sleeve have a larger diameter so that the developing sleeve can be brought into contact with electrostatic latent images more times.
Such measures can be effective for improving developability, but may greatly limit the lifetime of apparatus because of an in-machine contamination due to toner scatter occurring in developing assemblies or because of an overload on the drive of developing assemblies. In some instances, measures are also taken in which developers are put in developing assemblies in large quantities in order to compensate the insufficiency of developability of the developers. Such measures, however, cause an increase in weight of copying machines, a cost increase due to the apparatus that must be made larger in size and an overload on the drive of developing assemblies as in the above case, and are not so much preferable.
Now, studies are reported on improvements made from both directions of toners and carriers for the purpose of maintaining a high image quality over a long period of running.
For example, Japanese Patent Applications Laid-open No. 51-3238, No. 58-144839 and No. 61-204646 suggest average particle diameter and particle size distribution of carriers. Of these, Japanese Patent Application Laid-open No. 51-3238 makes reference to a rough particle size distribution. It, however, has no specific disclosure as to magnetic properties closely concerned with developing performance of developers or transport performance thereof in developing apparatus. Moreover, carriers used in Examples all contain particles with a size of 250 mesh-pass or larger in an amount of as large as about 80% by weight or more and also have an average particle diameter of 60 .mu.m or larger.
Japanese Patent Application Laid-open No. 58-144839 only discloses average particle diameter of a carrier. It makes reference to the quantity of fine powder that influences the adhesion of carriers to photosensitive members and the quantity of coarse powder that influences the sharpness of images. It takes account of performance of color copying, and has no detailed disclosure as to particle size distribution of carriers. As for Japanese Patent Application Laid-open No. 61-204646, it discloses as the gist of the invention a combination of a copying machine with a suitable developer, and has no specific disclosure as to the particle size distribution or magnetic properties of carriers. It still also has no disclosure as to why such a developer is effective for copying apparatus.
Japanese Patent Application Laid-open No. 49-70630 has a disclosure relating to magnetic force of carriers, which, however, is concerned with iron powders used as carrier materials, having a larger specific gravity than ferrites, also having a high saturation magnetization. Such iron powder carriers have been hitherto put into wide use, but tend to make the weight of copying machines larger or cause an overload on drive torque, and also have a large environmental dependence.
A ferrite carrier disclosed in Japanese Patent Application Laid-open No. 58-23032 concerns a porous material with many voids. Such a carrier tends to cause the edge effect, having a poor durability, and has been found to be unsuitable for color copy carriers.
It has long been sought to provide a developer that enables continuous reproduction of images with a large image area, using a developer in a small quantity, and can satisfy the performance specific to color copying that no edge effect may occur even after running. Studies are made on developers and carriers, almost all of which, however, are proposed taking account of black and white copying, and only a little of which are proposed as those applicable also to full-color copying. It is also sought to provide a carrier having the ability to continue reproduction of images having an image area of 20% or more, which are nearly solid images, and having the ability to decrease the edge effect and retain the uniformity of image density on a sheet of reproduction.
Under such circumstances, the present inventors have proposed, as disclosed in Japanese Patent Application Laid-open No. 2-281280, a carrier with a narrow particle size distribution in which the presence of fine powder and the presence of coarse powder have been quantitatively controlled, to achieve a carrier improved in developing performance.
However, as previously stated, there is an increasing commercial demand for making copying machines achieve a higher minuteness and making images have a higher quality. In the present technical field, it is attempted to make toner particle diameter smaller so that a color image can be formed in a high image quality. Making the particle diameters of toner particles smaller results in an increase in the surface area per unit weight, tending to bring about an excessively large quantity of triboelectricity of the toner. This is accompanied with a possibility of the insufficiency of image density or the deterioration of running performance.
Thus, for the purpose of preventing the insufficiency of image density or the deterioration of running performance, caused by the toner made to have a smaller particle diameter, or for the purpose of improving development efficiency, it is attempted to make carrier particles have a smaller diameter. Such carriers, however, have achieved no quality high enough to stand against changes in the environment of toners or changes in the quantity of triboelectricity after running.

Carrier for electrophotography, two-component type developer, and image forming method


The present disclosure provides a laser speed measuring method, control device and a laser velocimeter, and relates to the technical field of security inspection. The laser speed measuring method comprises the steps of: acquiring detection data within a predetermined detection angle range in a plurality of paralleled horizontal planes having different heights, from a plurality of laser rays detected towards a road extending direction in the horizontal plane; acquiring three-dimensional point cloud data according to the detection data; determining a position of a measured object in the road extending direction according to the three-dimensional point cloud data; and determining a speed of the measured object according to the position change of the measured object along the road extending direction at different timing.

The laser velocimeter adopts the principle of laser ranging. The laser ranging is to determine a distance between a measured object and a test point by emitting a laser beam to the measured object, receiving a reflected wave of the laser beam and recording a time difference. The laser Doppler velocity technique is to carry out laser ranging twice with a specific time interval on the measured object to obtain a moving distance of the measured object during the time interval, thereby deriving the moving speed of the measured object.

Laser speed measuring method, control device and laser velocimeter


Novel hydrogels that can serve as 3D hypoxic microenvironments are disclosed. Oxygen controllable, hypoxia-inducible hydrogels (HI hydrogels) are composed of a phenolic agent and polymer backbone, which can form hydrogel networks via oxygen consumption in an enzyme-mediated crosslinking reaction. The HI hydrogels are degradable, cytocompatible, and have tunable mechanical properties. Oxygen levels and gradients within the HI hydrogels are controlled and precisely predicted. As a result, the HI hydrogels induce prolonged hypoxic conditions. The HI hydrogels guide vascular morphogenesis in vitro by activating hypoxia-inducible factors and promote neovascularization from tissue, as well as stimulate tissue in dynamic in vivo environments. The HI hydrogels are a new class of biomaterials that are useful in many applications, ranging from the engineering of de novo tissues and disease models to the treatment of vascular disorders.

An emerging paradigm in the mimicry of three-dimensional (3D) microenvironments involves using a variety of bioinspired materials to reconstruct critical aspects of the native extracellular niche (Huebsch et al., Nature, 2009; 462: 426-432; Place, E. S., et al., Nature materials, 2009; 8: 457-470. Synthetic hydrogels have attracted substantial attention as 3D microenvironments owing to their structural similarity to the natural extracellular matrix (ECM) and their tunable properties. (Cushing, M. C., et al., Science, 2007; 316: 1133-1134; Lutolf, M. P. et al., Nature biotechnology, 2005; 23: 47-55; Place, E. S. et al., Nat. Mater. 2009, 8, 457; Annabi, N. et al., Adv. Mater. 2014, 26, 85: Malda, J. et al., Adv. A ater. 2013, 25, 5011: Thiele, J. et al., Adv. Mater. 2014, 26, 125). Researchers have endeavored to develop synthetic hydrogels to recapitulate temporal and spatial complexity in the native ECM, which varies not only in composition, but also in physicochemical parameters, including cell adhesion ligands (Luo, Y., et al., Nature materials, 2004; 3: 249-253), growth factors/cytokines (Martino, M. M., et al., Science translational medicine, 2011; 3: 100ra189), mechanical properties (Engler, A. J., et al., Cell, 2006; 126: 677-689), proteolytic degradability (Lutolf, M. P., et al., PNAS USA, 2003; 100: 5413-5418), and topography (Kilian, K. A., et al., PNAS USA, 2010; 107: 4872-4877). Thus, these studies have established how such parameters individually or synergistically regulate cell behavior.
Oxygen (dioxygen, O2) is vital for the existence of all multicellular organisms, acting as a signaling molecule for cells and regulating their metabolism, survival, cell-to-cell interactions, migration, and differentiation (Semenza, G. L., Science. 2007; 318:62-64; Covello, K. L. et al., Current topics in developmental biology, 2004; 62:37-54). In particular, O2 deprivation (below 5% partial pressure of O2, defined as hypoxia) is an important physiological signal, which presents in the native extracellular matrix (ECM) in various tissues (Simon, M. C. and Keith, B., Nat. Rev. Mol. Cell Biol. 2008, 9, 285; Simon, M. C. and Keith, B., Cell 2007, 129, 465). O2 tension in the mammalian reproductive tract is in the range of 1.5-8% (Fischer, B. and Bavister, B. D., J. Reprod. Fertil. 1993, 99, 673). During embryonic development and adult tissue regeneration and remodeling, cellular differentiation is regulated by generation of hypoxic microenvironments (Semenza, G. L., Trends Mol. Med. 2001, 7, 345). Indeed, hypoxia occurs in pathological conditions, such as tissue ischemia and inflammation as well as in solid tumors (Maltepe, E. and Simon, M. C., J. Mol. Med. 1998, 76, 391). Furthermore, hypoxia is a crucial physiological signal in wound healing and regeneration (LaVan, F. B. and Hunt, T. K., Clin. Plast. Surg. 1990, 17, 463; Du, J. et al., Gene Ther. 2013, 20, 1070). The O2 tension in the wound area decreases due to the disruption of the local microvasculature, which induces acute local hypoxia. Acute hypoxia plays a role as an important physiological signal during all phases of wound healing as it regulates cellular proliferation, migration, and differentiation through the induction of cytokines and diverse intracellular signaling pathways (W. X. Hong, et al., Adv. Wound Care 2014; E. A. O'Toole, et al., J. Clin. Invest. 1997, 100, 2881). To activate downstream signaling pathways and to facilitate accumulation of relevant transcription factors, hypoxic conditions must be maintained for several hours (>1 hour) (D. M. Stroka, et al., FEBS J. 2001, 15, 2445).
Cellular responses to O2 deprivation (hypoxia) are primarily regulated by hypoxia-inducible factors (HIFs) that accumulate under hypoxic conditions and activate the expression of numerous genes that regulate myriad cellular activities (Keith, B. et al., Cell, 2007; 129:465-472). HIFs act as key regulators, promoting angiogenesis during embryonic development, tumor progression, and tissue regeneration (Simon, M. C. et al., Nature reviews: Molecular cell biology, 2008; 9:285-296; Heddleston, J. M. et al., British J Cancer, 2010; 102:789-795; Jopling, C. et al., Circulation, 2012; 126:3017-3027). HIFs regulate the expression of many angiogenic genes that promote vascular differentiation and morphogenesis, such as vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor 2 (VEGFR2) (Ferrara, N., et al., Nature medicine, 2003; 9:669-676; Lee, Y. M. et al., Developmental dynamics, 2001; 220:175-186; Gassmann, M. et al., PNAS USA, 1996; 93:2867-2872), angiopoietin 1 (ANG1) (Augustin, H. G. et al., Nature reviews. Molecular cell biology 2009; 10:165-177), as well as matrix metalloproteinases (MMPs) (Fong, G. H., Journal of molecular medicine, 2009; 87:549-560; Manalo, D. J. et al., Blood, 2005; 105:659-669; Ottino, P. et al., Molecular vision, 2004; 10:341-350; Pugh, C. W. et al., Nature medicine, 2003; 9:677-684; Ben-Yosef, Y. et al., Circulation research, 2002; 90:784-791). Hypoxia, low oxygen tension, plays a pivotal role during development, regeneration, and cancer. Although hypoxia is an important factor in vascular development, hypoxia has not been simulated in a 3D microenvironment. The present invention addresses the need for fundamental technology and materials that can serve as 3D hypoxic microenvironments.

Methods of inducing vascular morphogensis


A method of patterning a layer of magnetic material to form isolated magnetic regions. The method forms a mask on a film stack comprising a layer of magnetic material such that the protected and unprotected regions are defined. The unprotected regions are etched in a high temperature environment to form isolated magnetic regions.

1. Field of the Invention
The present invention generally relates to a method for fabricating devices on semiconductor substrates. More specifically, the invention relates to a method of patterning a layer of magnetic material for fabrication of a magneto-resistive random access memory (MRAM) device.
2. Description of the Related Art
Magneto-resistive random access memory (MRAM) has been developed as a new type of non-volatile memory. Digital information in MRAM is represented by the direction of magnetization of a magnetic material. MRAM has a plurality of memory cells that are interconnected to one another to facilitate storage of information within the MRAM. A memory cell in an MRAM device generally is a multi-layered structure comprising a pair of magnetic layers separated by a tunneling layer. These layers are deposited as overlying blanket films, layer-by-layer, and then featured to form a MRAM device. More specifically, the MRAM device comprises a free (or top) magnetic layer that may change a direction of magnetization and a bottom magnetic layer that has a fixed direction of magnetization. The magnetic layers are separated by a thin tunneling layer formed of a non-magnetic dielectric material such as aluminum oxide (Al2O3) and the like. The top and bottom magnetic layers may each comprise a plurality of layers of magnetic materials such as permalloy (NiFe), cobalt iron (CoFe), platinum manganese (PtMn), iridium manganese (IrMn) and the like. The top and bottom magnetic layers are also supplied with film electrodes (e.g., comprising conductors such as tantalum (Ta), tantalum nitride (TaN), copper (Cu), and the like) to form an electrical connection for the memory cell to the lines of the MRAM.
Fabrication of a MRAM device comprises etch processes in which one or more layers that comprise a film stack are removed, either partially or in total. The MRAM device comprises the layers that are generally formed from materials that may be easily oxidized, sensitive to corrosion or very thin and as such are difficult to etch with no damage to the stack. In the prior art, during etching a MRAM film stack, the etchants may leave metal-containing residues. Such a problem arises from low etch selectivity and non-volatile nature of by-products that are formed during an etch process. Such residues may accumulate along the sides of the film stack and form a conductive veil-like pattern instead of being suspended in a plasma and eventually exhausted from the processing environment. The conductive residues may cause electrical short-circuits within a MRAM device, e.g., between the magnetic layers separated by the tunnel layer, or may render the MRAM device to operate sub-optimally or not at all.
Therefore, there is a need in the art for a method of patterning magnetic materials for fabrication a magneto-resistive random access memory (MRAM) device.


A method for recovering technical-grade molybdenum from diluted acid leaching solutions (PLS) that have a high arsenic concentration is disclosed. The method includes: (a) contacting a pre-filtered PLS with an anionic ion-exchange resin; (b) washing the loaded resin with water; (c) extracting molybdenum from the resin with an alkaline ammonium regenerant solution to form ammonium molybdenum in solution; (d) washing the unloaded resin with water; (e) adding iron and/or magnesium salts to the recovered ammonia solution to obtain a precipitate which is transferred to the arsenic abatement step and a solution containing ammonium molybdate; (f) adding sulphuric acid to the arsenic-free ammonia solution to precipitate ammonium molybdate; (g) separating the precipitate by filtering the molybdate and re-circulating the solution obtained with the initial PLS; (h) calcining the separated precipitate to obtain ammonia and molybdenum trioxide; and (i) recovering the released ammonia for subsequent use as a recirculated regenerant solution.

A mining process or method is the summation of methods through which, starting from a deposit, metals and/or metallic compounds of commercial purity and quality are obtained, in a profitable manner and with an acceptable environmental impact.
In the known leaching process, one or many mineral values contained in an ore or a concentrate are dissolved, generally using an aqueous solution of a leaching agent. The term can also be extended to include dissolving secondary materials, such as scrap metals, residues, and waste.
Leaching produces an aqueous solution rich in extracted ions of the valued metal (PLS, pregnant leaching solution) from which it is possible to separate this metal and recover it with a high level of purity. Also, a solid residue or gravel is produced, that, ideally, has a sufficiently low level of valued leached minerals, as to discard it in tailings or dump.
If the solid leaching residue is impregnated with salts or precipitates that eventually can release toxic agents once exposed to the environment, before discard, the residue must be properly treated in order to achieve elimination or stabilization of the potentially contaminant compounds. In some cases, leaching can have a different objective than the one previously described. For example, when a concentrate is leached for selectively extracting certain impurities, and leaching processes increase the quality of concentrate (for example during removal of copper from molybdenite concentrates).
In purification and enrichment processes of solutions, leaching processes are not necessarily selective and consequently produce leaching solutions containing, besides the metal of interest, a range of impurities. This, added to the fact that concentration of the metal of interest may not be too high, makes direct recovery of the metal of interest from the leaching solution impossible. Accordingly, these solutions must be pre-treated through purification and enrichment steps.
Purification eliminates impurities, effectively isolating valuable elements. Enrichment of solutions is also particularly beneficial for reducing the volumes of solution to be treated in subsequent steps of metal recovery. This decreases investment costs and increases efficiency in recovery.
In the present invention, a process for recovery of molybdenum as molybdenum trioxide, from diluted acid leaching solutions of metallurgic residues, having a high concentration of arsenic, antimony, or bismuth, is disclosed.
The object of the present invention is to recover molybdenum, through ion exchange, contained in diluted leaching solutions containing molybdenum, but having a high concentration of arsenic, among other impurities, in such a manner that a molybdenum product is obtained efficiently and profitably.
Prior art includes documents disclosing molybdenum recovery through ion exchange. Such is the case of U.S. Pat. No. 4,891,067, disclosing a process for selective separation of molybdenum present in an acid solution at pH 2 and containing molybdenum and at least one of the elements in the group consisting of uranium, iron, arsenic, phosphorous, silicon, and vanadium. Such a process comprises contacting the acid solution with a stationary phase consisting of a resin with an active oxime group, and eluting the stationary phase with an alkaline solution to recover molybdenum. U.S. Pat. No. 4,596,701 discloses a procedure for purifying molybdenum trioxide, specifically disclosing a method for preparing ammonium molybdate comprising contacting a concentrate with an aqueous solution of sulfuric acid, ammonium, ammonium sulfate and persulfate, and solubilizing at least 2% of the molybdenum present in the concentrate.
A Chilean patent application CL N° 3137-2005 discloses a process for molybdenum and copper extraction, which are contained in solidified slags from fusion processes in copper concentrates. This document does not interfere with the present patent application since the slag does not contain arsenic, therefore treating a technical problem different to the one addressed in the present patent application.
None of the previously mentioned processes interfere with the present application since such documents of the prior art show processes with different operative variables, and therefore, do not provide the benefits obtained with the present invention, which include efficiently and profitably recovering technical grade MoO3 (molybdenum trioxide) from leaching solutions with high arsenic content. Through the present invention, a technical grade molybdenum trioxide is obtained, which means having a molybdenum content over 58%, and a content of non-regulated metals, such as As, Sb, and Bi, in amounts lower than 0.1%.

Process for recovery of technical grade molybdenum from diluted leaching acid solutions (PLS), with highly concentrated arsenic, from metallurgical residues


A rear projection-type screen includes two sheet-like members having lenses prevented from being deformed and scratched. In the rear projection-type screen (5) for passing and focusing image light L emitted from an image light source (3), two sheet-like members (a lenticular lens sheet 7 and a Fresnel lens sheet 8) each made of a transparent material and having minute lenses (9) and (11) formed on at least one surface thereof are disposed such that their surfaces (7b) and (8a) with the lenses formed thereon confront each other, and a plurality of spacers (14), (14), . . . are disposed at appropriate spaced intervals between the confronting lenses of the two sheet-like members within an effective screen area (5a) for passing and focusing the image light thereon.

In recent years, there has widely been used a rear projection-type image display device (hereinafter simply referred to as "image display device") for projecting image light, onto a rear projection-type screen (hereinafter simply referred to as "projection screen") at an enlarged scale achieved by projection means such as a projection lens or the like. The image light is modulated by an image signal emitted from a relatively small image light source such as a cathode-ray tube (CRT) display unit, a liquid-crystal display (LCD) unit, a digital mirror device (DMD), or the like.
In the above image display device, generally, the image light projected onto the rear surface of the projection screen passes through the projection screen and is focused in the vicinity of the front surface thereof, and the focused image light is recognized by the observer in the front direction of the image display device.
FIG. 13 shows an example "a" of the projection screen of a conventional rear projection-type image display device. The projection screen "a" has two sheet-like members closely spaced from each other by a suitable distance.
When the observer views the image display device, an angular distribution of horizontal viewing positions of the observer is greater than an angular distribution of vertical viewing positions of the observer. Therefore, the rear projection-type image display device is required to obtain emitted light in a wider angle in the horizontal direction than in the vertical direction.
The two sheet-like members of the projection screen "a" include, respectively, a lenticular lens sheet "c" having a lenticular lens "b" including a number of cylindrical lenses b1, b1, . . . extending vertically on its rear surface, and a Fresnel lens sheet "e" closely spaced a suitable distance from the lenticular lens sheet "c" and having a Fresnel lens "d" on its surface (front surface) facing the lenticular lens sheet "c".
Image light is emitted from an image light source (not shown) and projected at an enlarged scale by projection means onto the rear surface of the projection screen "a". The image light is converted into parallel rays of light by the Fresnel lens "d" of the Fresnel lens sheet "e", and then the parallel rays of light are focused by the lenticular lens "b" of the lenticular lens sheet "c" onto a number of linear focused points f, f, . . . extending vertically at positions near the front surface of the lenticular lens sheet "c" (see FIG. 13). The image light focused onto the focused points f, f, . . . is spread in the horizontal direction wherein the distribution of viewing positions of the observer is greater. The Fresnel lens "d" of the Fresnel lens sheet "e" is also effective to improve a reduction in luminance at the four corners of the projection screen "a".
The lenticular lens sheet "c" and the Fresnel lens sheet "e" are of a structure in which the lenticular lens "b" or the Fresnel lens "d" formed of ultraviolet (UV)-curable resin is laminated on a base of acrylic resin, or a structure in which the lenticular lens "b" or the Fresnel lens "d" and the base are integrally formed of acrylic resin.
With the conventional rear projection-type screen such as the projection screen "a" described above, it is ideal that the sheet-like lenses be held in contact with each in the central region thereof.
Generally, however, the sheet-like members such as the lenticular lens sheet and the Fresnel lens sheet are coupled integrally together by tapes applied to peripheral edges thereof. Consequently, the sheet-like members tend to be spaced from each other in the central region that is farthest from the peripheral edges. If the sheet-like members of the rear projection-type screen are too spaced from each other, then the image light may be focused into double images, which make the image blur.
With the conventional rear projection-type screen such as the projection screen "a" described above, as shown in FIGS. 14 and 15, it is customary to form one of the sheet-like members, e.g., the lenticular lens sheet "c", as a warped sheet-like member, place the warped lenticular lens sheet "c" over the other sheet-like member, i.e., the Fresnel lens sheet "e", apply a pressure to superpose the peripheral edge of the lenticular lens sheet "c" on the peripheral edge of the Fresnel lens sheet "e", and apply tapes "g" or the like to their peripheral edges to secure the lenticular lens sheet "c" and the Fresnel lens sheet "e" integrally to each other (see FIG. 15).
In the projection screen "a" shown in FIG. 15, since the lenticular lens sheet "c" is originally of the warped shape, after the lenticular lens sheet "c" and the Fresnel lens sheet "e" are integrally combined with each other, the lenticular lens "b" and the Fresnel lens "d" remain in contact with each other in the central region that is remotest from the secured peripheral edges thereof. Therefore, the lenticular lens sheet "c" and the Fresnel lens sheet "e" are prevented from being too spaced from each other.
With the sheet-like member such as the lenticular sheet lens c being warped beforehand, however, the lenticular lens sheet "c" and the Fresnel lens sheet "e" are possibly pressed against each other under strong forces in the central region. When the lenticular lens sheet "c" and the Fresnel lens sheet "e" are pressed against each other under strong forces, the lens elements of the lenticular lens "b" and the Fresnel lens "d" are strongly pressed against each other, tend to be deformed in shape, and changed in optical characteristics. As a result, the path of the emitted light may be changed to focus the light into a blurred image. In particular, Fresnel lenses are easily deformable when pressed because they are often made of a relatively soft UV-curable resin laminated on a base of acrylic resin.
Even if the lens elements of the lenticular lens "b" and the Fresnel lens "d" are not held in contact with each other under forces strong enough to deform them, when they are continuously vibrated as during shipment, the lens surfaces may be rubbed and scratched due to the contact between the lenses. The scratch may be liable to cause the projection screen "a" to display double or triple images thereon.
According to one solution, as shown in FIG. 15, the conventional rear projection-type screen such as the projection screen "a" has spacers h, h, . . . . The spacers h, h, . . . are suitable shape and size sandwiched between the lenticular lens sheet "c" and the Fresnel lens sheet "e" along the peripheral edge of the projection screen "a" through which the image light does not pass, i.e., which is outside of the effective screen area. The spacers h, h, . . . keep the lenticular lens sheet "c" and the Fresnel lens sheet "e" spaced from each other over their entire area, thereby keeping the lenticular lens "b" and the Fresnel lens "d" out of contact with each other in the central region.
However, since the spacers h, h, . . . are positioned in the peripheral edge that is located outside of the effective screen area mostly remotely from the central area of the projection screen "a", the method using spacers h, h, . . . poses a limitation on the ability to keep the lenticular lens "b" and the Fresnel lens "d" from contacting each other.
In view of the above problems, it is an object of the present invention to provide a rear projection-type screen including two sheet-like members for use in a rear projection-type image display device. The two sheet-like members are spaced an optimum distance from each other within an effective screen area to prevent lenses of the two sheet-like members from being deformed and scratched for increasing the quality of images displayed thereby.

Rear projection-type screen and rear projection-type image display device


The present disclosure relates to protein-polymer conjugates comprising an engineered binding oligomer protein and a polymer for detection of a ligand of interest, methods, compositions and kits thereof.

The highly-specific molecular recognition capabilities of proteins have enabled their widespread use in a variety of biosensor formats including lateral flow assays,1-4 microfluidics,5-8 and microarrays.9-10 In each of these biosensors, proteins are immobilized on a surface, where device sensitivity is enhanced by achieving densely-packed proteins that are well-oriented to allow free access to binding sites.11-13 The simplest and most general methods for protein surface functionalization involve covalent anchoring via free amines on the surfaces of proteins. Because these amines are distributed at multiple points across the protein surface, however, the resulting orientation is random, reducing the active proportion of the surface-immobilized binding protein. As such, there is significant interest in developing techniques that enable site-specific immobilization. Current directed immobilization strategies include modifying functional groups that appear at only a single location on a protein,14-15 adding ssDNA fragment linkers,16 or fusing to proteins17-18 and installing tags19-20 that display high binding affinity to a specific surface. While all of these methods can be used to orient proteins and improve biosensor performance, these approaches can only be used for specific classes of proteins or require significant protein and/or surface pre-treatment.
One potentially straightforward and effective technique for creating a dense array of properly oriented proteins is through utilization of block copolymer-like self-assembly. By conjugating a protein to a polymer and dissolving the bioconjugate in concentrated aqueous solution, it has been demonstrated that these conjugates assemble into ordered nanostructures similar to coil-coil diblock copolymers.21-23 While the individual ordered phases in both types of diblock copolymers are identical, the self-assembly of protein-polymer conjugates exhibits notable differences from that of traditional block copolymers. Protein-polymer conjugates display highly asymmetric phase behavior24 and re-entrant order-disorder transition (ODT) behavior,24-25 in contrast to the enhanced ordering in more concentrated block copolymer solutions predicted by the dilution approximation.26 A complete explanation for these deviations from characteristic block copolymer assembly has not yet been established, but it is known that coarse-grained features of the conjugates have significant effects on self-assembly: polymer topology,27 polymer chemistry,25 protein shape,28 and electrostatics29 have all been found to significantly affect phase behavior and ordering in protein-polymer block copolymers.


A fail-safe wall anchor for cavity walls includes a wingnut including receptors for receiving pintles of a veneer tie. Thermally insulative material is provided to inhibit transfer of heat from the veneer tie to the wall anchor. Back up structure is provided in the event the thermally insulative material fails to maintain the structural connection between the wall anchor and the veneer tie.

1. Field of the Invention
This invention relates to fail-safe anchoring systems for cavity walls. At the inner wythe, the anchoring systems provide a stud-type wall anchor with a hybrid connector portion for interlocking with a veneer anchor. The hybrid connector portion has two elements, namely, a thermoplastic portion and a metal stamping portion. Upon being subjected to a extreme heat or a fire, the thermoplastic portion is fail-prone and melts and the metal stamping portion is fail-safe and retains the veneer anchor. Under normal conditions, the thermoplastic portion provides a thermal break between the metal veneer anchor and the stud-type wall anchor.
2. Description of the Prior Art
In the past, anchoring systems have taken a variety of configurations. Where the applications included masonry backup walls, wall anchors were commonly incorporated into ladder- or truss-type reinforcements and provided wire-to-wire connections with box ties or pintle-receiving designs on the veneer side.
In the late 1980's, surface-mounted wall anchors were developed by Hohmann & Barnard, Inc., patented under U.S. Pat. No. 4,598,518 ('518). The invention was commercialized under trademarks DW-10®, DW-10-X®, and DW-10-HS®. These widely accepted building specialty products were designed primarily for drywall construction, but were also used with masonry backup walls. For seismic applications, it was common practice to use these wall anchors as part of the DW-10 Seismiclip® interlock system which added a Byna-Tie® wire formative, a Seismiclip® snap-in device—described in U.S. Pat. No. 4,875,319 ('319), and a continuous wire reinforcement.
In the dry wall application, the surface-mounted wall anchor of the above-described system has pronged legs that pierce the insulation and the wall board and rest against the metal stud to provide mechanical stability in a four-point landing arrangement. The vertical slot of the wall anchor enables the mason to have the wire tie adjustably positioned along a pathway of up to 3.625-inch (max). The interlock system served well and received high scores in testing and engineering evaluations which examined the effects of various forces, particularly lateral forces, upon brick veneer masonry construction. However, under certain conditions, the system did not sufficiently maintain the integrity of the insulation.
The engineering evaluations further described the advantages of having a continuous wire embedded in the mortar joint of anchored veneer wythes. The seismic aspects of these investigations were reported in the inventor's '319 patent. Besides earthquake protection, the failure of several high-rise buildings to withstand wind and other lateral forces resulted in the incorporation of a continuous wire reinforcement requirement in the Uniform Building Code provisions. The use of a continuous wire in masonry veneer walls has also been found to provide protection against problems arising from thermal expansion and contraction and to improve the uniformity of the distribution of lateral forces in the structure.
Shortly after the introduction of the pronged wall anchor, a seismic veneer anchor, which incorporated an L-shaped backplate, was introduced. This was formed from either 12- or 14-gauge sheetmetal and provided horizontally disposed openings in the arms thereof for pintle legs of the veneer anchor. In general, the pintle-receiving sheetmetal version of the Seismiclip® interlock system served well, but in addition to the insulation integrity problem, installations were hampered by mortar buildup interfering with pintle leg insertion.
In the late 1980's, an anchor for masonry veneer walls was developed and described in U.S. Pat. No. 4,764,069 by Reinwall et al., which patent is an improvement of the masonry veneer anchor of Lopez, U.S. Pat. No. 4,473,984. Here the anchors are keyed to elements that are installed using power-rotated drivers to deposit a mounting stud in a cementitious or masonry backup wall. Fittings are then attached to the stud which include an elongated eye and a wire tie therethrough for disposition in a bed joint of the outer wythe. It is instructive to note that pin-point loading—that is forces concentrated at substantially a single point—developed from this design configuration. Upon experiencing lateral forces over time, this resulted in the loosening of the stud.
Exemplary of the public sector building specification is that of the Energy Code Requirement, Boston, Mass. (See Chapter 13 of 780 CMR, Seventh Edition). This Code sets forth insulation R-values well in excess of prior editions and evokes an engineering response opting for thicker insulation and correspondingly larger cavities.
As insulation became thicker, the tearing of insulation during installation of the pronged DW-10X® wall anchor, see supra, became more prevalent. This occurred as the installer would fully insert one side of the wall anchor before seating the other side. The tearing would occur during the arcuate path of the insertion of the second leg. The gapping caused in the insulation permitted air and moisture to infiltrate through the insulation along the pathway formed by the tear. While the gapping was largely resolved by placing a self-sealing, dual-barrier polymeric membrane at the site of the legs and the mounting hardware, with increasing thickness in insulation, this patchwork became less desirable. The improvements hereinbelow in surface mounted wall anchors look toward greater retention of insulation integrity and less reliance on a patch.
In the past, the use of wire formatives have been limited by the mortar layer thickness which, in turn, are dictated either by the new building specifications or by pre-existing conditions, e.g. matching during renovations or additions to the existing mortar layer thickness. While arguments have been made for increasing the number of the fine-wire anchors per unit area of the facing layer, architects and architectural engineers have favored wire formative anchors of sturdier wire.
Contractors found that heavy wire anchors, with diameters approaching the mortar layer height specification, frequently result in misalignment. This led to the low-profile wall anchors of the inventors hereof as described in U.S. Pat. No. 6,279,283. However, the above-described technology did not fully address the adaption thereof to insulated inner wythes utilizing stabilized stud-type devices.
Another prior art development occurred shortly after that of Reinwall/Lopez when Hatzinikolas and Pacholok of Fero Holding Ltd. introduced their sheetmetal masonry connector for a cavity wall. This device is described in U.S. Pat. Nos. 5,392,581 and 4,869,043. Here a sheetmetal plate connects to the side of a dry wall column and protrudes through the insulation into the cavity. A wire tie is threaded through a slot in the leading edge of the plate capturing an insulative plate thereunder and extending into a bed joint of the veneer. The underlying sheetmetal plate is highly thermally conductive, and the '581 patent describes lowering the thermal conductivity by foraminously structuring the plate. However, as there is no thermal break or barrier, a concomitant loss of the insulative integrity results.
The construction of a steel-framed inner wythe of a commercial building, to which masonry veneer is attached, uses steel studs with insulation installed outboard of the steel stud framing. Steel anchors and ties attach the outer wythe to the inner wythe by screwing or bolting an anchor to a steel stud. Although steel offers many benefits, it does not provide the high insulation efficiency of timber framing and can cause the effective R-value of fiberglass batt insulation between the steel studs to fall 50 to 60%.
Steel is an extremely good conductor of heat. The use of steel anchors attached to steel framing draws heat from the inside of a building through the exterior sheathing and insulation, towards the exterior of the masonry wall. In order to maintain high insulation values, a thermal break or barrier is needed between the steel framing and the outer wythe. This is achieved by the present invention through the use of high-strength polymeric components which have low thermal conductivity. Removing the steel portions of the anchor at specific locations and replacing the steel with a high-strength polymeric material with a lower thermal conductivity than steel, causes a thermal break and significantly reduces the transfer of heat.
In the course of prosecution, wall anchor patents indicated by an asterisk on the tabulation below, came to the attention of the inventor and are believed to be relevant in this discussion of the prior art. A more extensive list of patents known to the inventor is included in the Information Disclosure Statement. Thereafter and in preparing for this disclosure, the additional patents which became known to the inventors are discussed further:
Pat.InventorIssue Date2,058,148*HardOct. 20, 19362,966,705*MasseyJan. 3, 19613,377,764StorchApr. 16, 19684,021,990*SchwalbergMay 10, 19774,305,239*GeraghtyDec. 15, 19814,373,314AllanFeb. 15, 19834,438,611*BryantMar. 27, 19844,473,984LopezOct. 2, 19844,598,518HohmannJul. 8, 19864,869,038CataniSep. 26, 19894,875,319HohmannOct. 24, 19895,392,581Hatzinikolas, et. al.Feb. 28, 19955,408,798HohmannApr. 25, 19955,456,052Anderson et al.Oct. 10, 19955,816,008HohmannOct. 6, 19986,209,281RiceApr. 3, 20016,279,283Hohmann et al.Aug. 28, 20017,415,803BronnerAug. 26, 20088,037,653Hohmann, Jr.Oct. 18, 2011
It is noted that with some exceptions these devices are generally descriptive of wire-to-wire anchors and wall ties and have various cooperative functional relationships with straight wire runs embedded in the inner and/or outer wythe.
U.S. Pat. No. 3,377,764—D. Storch—Issued Apr. 16, 1968 discloses a bent wire, tie-type anchor for embedment in a facing exterior wythe engaging with a loop attached to a straight wire run in a backup interior wythe.
U.S. Pat. No. 4,021,990—B. J. Schwalberg—Issued May 10, 1977 discloses a dry wall construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Like Storch '764, the wall tie is embedded in the exterior wythe and is not attached to a straight wire run.
U.S. Pat. No. 4,373,314—J. A. Allan—Issued Feb. 15, 1983 discloses a vertical angle iron with one leg adapted for attachment to a stud and the other having elongated slots to accommodate wall ties. Insulation is applied between projecting vertical legs of adjacent angle irons with slots being spaced away from the stud to avoid the insulation.
U.S. Pat. No. 4,473,984—Lopez—Issued Oct. 2, 1984 discloses a curtain-wall masonry anchor system wherein a wall tie is attached to the inner wythe by a self-tapping screw to a metal stud and to the outer wythe by embedment in a corresponding bed joint. The stud is applied through a hole cut into the insulation.
U.S. Pat. No. 4,869,038—M. J. Catani—Issued Sep. 26, 1989 discloses a veneer wall anchor system having in the interior wythe a truss-type anchor, similar to Hala et al. '226, supra, but with horizontal sheetmetal extensions. The extensions are interlocked with bent wire pintle-type wall ties that are embedded within the exterior wythe.
U.S. Pat. No. 4,875,319—R. Hohmann—Issued Oct. 24, 1989 discloses a seismic construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Wall tie is distinguished over that of Schwalberg '990 and is clipped onto a straight wire run.
U.S. Pat. No. 5,392,581—Hatzinikolas et al.—Issued Feb. 28, 1995 discloses a cavity-wall anchor having a conventional tie wire for mounting in the brick veneer and an L-shaped sheetmetal bracket for mounting vertically between side-by-side blocks and horizontally atop a course of blocks. The bracket has a slit which is vertically disposed and protrudes into the cavity. The slit provides for a vertically adjustable anchor.
U.S. Pat. No. 5,408,798—Hohmann—Issued Apr. 25, 1995 discloses a seismic construction system for a cavity wall having a masonry anchor, a wall tie, and a facing anchor. Sealed eye wires extend into the cavity and wire wall ties are threaded therethrough with the open ends thereof embedded with a Hohmann '319 (see supra) clip in the mortar layer of the brick veneer.
U.S. Pat. No. 5,456,052—Anderson et al.—Issued Oct. 10, 1995 discloses a two-part masonry brick tie, the first part being designed to be installed in the inner wythe and then, later when the brick veneer is erected to be interconnected by the second part. Both parts are constructed from sheetmetal and are arranged on substantially the same horizontal plane.
U.S. Pat. No. 5,816,008—Hohmann—Issued Oct. 6, 1998 discloses a brick veneer anchor primarily for use with a cavity wall with a drywall inner wythe. The device combines an L-shaped plate for mounting on the metal stud of the drywall and extending into the cavity with a T-head bent stay. After interengagement with the L-shaped plate the free end of the bent stay is embedded in the corresponding bed joint of the veneer.
U.S. Pat. No. 6,209,281—Rice—Issued Apr. 3, 2001 discloses a masonry anchor having a conventional tie wire for mounting in the brick veneer and sheetmetal bracket for mounting on the metal-stud-supported drywall. The bracket has a slit which is vertically disposed when the bracket is mounted on the metal stud and, in application, protrudes through the drywall into the cavity. The slit provides for a vertically adjustable anchor.
U.S. Pat. No. 6,279,283—Hohmann et al.—Issued Aug. 28, 2001 discloses a low-profile wall tie primarily for use in renovation construction where in order to match existing mortar height in the facing wythe a compressed wall tie is embedded in the bed joint of the brick veneer.
U.S. Pat. No. 7,415,803—Bronner—Issued Aug. 26, 2008 discloses a double-wingnut anchor system and method for connecting an anchor shaft extending from the backup wall to a wire tie extending from a veneer wall. The wingnut houses the wire tie legs and is independently rotatable to obtain the desired angular position.
U.S. Pat. No. 8,037,653—Hohmann, Jr.—Issued Oct. 18, 2011 discloses a dual seal anchoring system for insulated cavity walls. The stud anchor has a dual-diameter barrel with thermally-isolating seals.
None of the above provide the high-strength, supported stud-type wall anchor or anchoring systems utilizing these devices of this invention. As will become clear in reviewing the disclosure which follows, the cavity wall structures benefit from the recent developments described herein that lead to solving the problems of thermal conductivity by providing an in-cavity thermal break and of anchor integrity by having a hybrid wall anchor with both a failure-prone and a fail-safe receptor portions. The anchoring systems hereof combine various wall anchors for self-leveling installation and include reinforcement for seismic protection.

This patent is subject to a terminal disclaimer.

Fail-safe anchoring systems for cavity walls


An evaporated fuel treatment device comprising a purge control valve arranged between a canister and an intake passage of an engine. A drive pulse of the purge control valve is controlled by a duty ratio. When the engine operating state is one in which a large amount of evaporated fuel is produced in the fuel tank, the feedback correction coefficient is maintained at a is position deviated from the reference value so as to enable the feedback correction coefficient to change in accordance with the fluctuations of the air-fuel ratio.

1. Field of the Invention
The present invention relates to an evaporated fuel treatment device of an engine.
2. Description of the Related Art
Known in the art is an internal combustion engine provided with a canister for temporarily storing evaporated fuel and a purge control valve for controlling the amount of purge of the fuel vapor to be purged from the canister to the inside of an intake passage and using the purge control valve to control the amount of purge of the fuel vapor so that the purge rate of the fuel vapor becomes a predetermined target purge rate (see Japanese Unexamined Patent Publication (Kokai) No. 7-305646). In this internal combustion engine, the amount of fuel injection is corrected by a feedback correction coefficient and a purge air fuel ratio correction coefficient so as to suitably maintain the air-fuel ratio at the target air-fuel ratio.
That is, in a usual internal combustion engine, the basic fuel injection time required for making the air-fuel ratio the stoichiometric air-fuel ratio is found in advance by experiments and stored and the basic fuel injection time is corrected by a feedback control coefficient so that the air-fuel ratio becomes the stoichiometric air-fuel ratio based on an output signal of an air-fuel ratio sensor provided in the engine exhaust passage. In this case, the feedback control coefficient is normally set to repeatedly fluctuate about a reference value, for example, 1.0.
On the other hand, when the purge action of fuel vapor is started, the basic fuel injection time is corrected by the purge air-fuel ratio correction coefficient showing the vapor concentration in the intake air. The feedback control coefficient repeatedly fluctuates about 1.0 even during the purge action. That is, when the purge action is started, the air-fuel ratio becomes rich, so the feedback control coefficient falls to where the air-fuel ratio becomes the stoichiometric air-fuel ratio. The amount of drop of the feedback control coefficient at this time shows the vapor concentration In the intake air. Therefore, to find the vapor concentration there, the purge air-fuel ratio correction coefficient is gradually updated until the feedback control coefficient returns to 1.0. In this case, the final purge air-fuel ratio correction coefficient comes to show the vapor concentration and the fuel injection time is shortened by exactly the amount of the final purge A/F correction coefficient. When the final purge A/? correction coefficient is calculated, the feedback control coefficient once again fluctuates about 1.0.
Note that in actuality, the narrow range about 1.0 is set for the feedback control coefficient for calculating the vapor concentration. Only when the feedback control coefficient exceeds this set range is the purge A/F correction coefficient reduced or increased so that the feedback control coefficient returns to the set range. By correcting the amount of fuel injection by the feedback control coefficient and the vapor air-fuel ratio correction coefficient in this way, the air-fuel ratio is maintained at the stoichiometric air-fuel ratio even when a purge action is being performed.
On the other hand, if the feedback control coefficient deviates widely from 1.0 due to some reason or another, the air-fuel ratio will become excessively lean or excessively rich. Therefore, it is necessary to prevent the feedback control coefficient from deviating widely from 1.0 in this way. Therefore, usually, an allowable limit of fluctuation is set for the feedback control coefficient and the feedback control coefficient is made to only be able fluctuate within this allowable limit of fluctuation.
Since, however, the fuel vapor is sucked into the intake passage by the difference in the pressure in the canister and the pressure inside the intake passage, if the degree of opening of the purge control valve is made constant, the larger the vacuum in the intake passage, the greater the purge rate will become. Therefore, in this case, to maintain the purge rate constant, the greater the vacuum in the intake passage, the smaller the degree of opening of the purge control valve must be made. Accordingly, in the past, to maintain the purge rate at the target purge rate, the degree of opening of the purge control valve has been controlled in is accordance with the operating state of the engine.
The fuel vapor absorbed in the activated charcoal in the canister, however, is sucked into the intake passage by the difference between the pressure in the canister and the pressure in the intake passage, so if the degree of opening of the purge control valve were controlled in accordance with the operating state of the engine in the above way when the fuel vapor absorbed in the activated charcoal of the canister was being purged, it would be possible to maintain the purge rate at the target purge rate and therefore prevent the air-fuel ratio from fluctuating.
A little after the engine starts operating, however, the rise of the temperature of the fuel in the fuel tank and vibration cause a large amount of evaporated fuel to be generated in the fuel tank. The evaporated fuel generated in the fuel tank is made to flow through a purge passage directly into the intake passage. In this case, however, since the fuel vapor is pushed out from the fuel tank into the intake passage, the amount of the fuel vapor supplied from the fuel tank to the intake passage is not dependent on the magnitude of the vacuum generated in the intake passage, but is dependent on the amount of the evaporated fuel generated in the fuel tank. Therefore, if the amount of the fuel vapor which is directly supplied from the fuel tank to the inside of the intake passage increases, even if the purge control valve is used to control the purge rate to a target purge rate, the concentration of fuel vapor in the intake air will greatly change in accordance with a change in the amount of purge.
That is, when the purge rate is controlled to become the target purge rate, if the amount of intake air falls, the amount of purge will be reduced, while if the amount of intake air increases, the amount of purge will be increased. In this case, if the amount of purge is increased, the amount of purge of the fuel vapor from the canister will be increased in exact proportion and the amount of purge of the fuel vapor from the fuel tank will be maintained constant. Therefore, if the amount of purge is increased, the concentration of fuel vapor in the intake air will become lower. If the amount of fuel vapor directly supplied from the fuel tank to the inside of the intake passage is increased in this way, when the amount of purge increases, the concentration of fuel vapor in the intake air will become lower, while when the amount of purge decreases, the concentration of fuel vapor in the intake air will become higher.
Note that even when the concentration of fuel vapor fluctuates widely in accordance with the changes in the amount of purge in this way, if the feedback control coefficient is changed to track these changes of the concentration of fuel vapor, the air-fuel ratio will not fluctuate that much. That is, for example, if the amount of intake air falls and the amount of purge falls like at the time of a deceleration operation, the concentration of fuel vapor will widely increase and therefore the feedback control coefficient will become smaller to maintain the air-fuel ratio at the stoichiometric air-fuel ratio. At this time, if the feedback control coefficient can be kept smaller until the air-fuel ratio reaches the stoichiometric air-fuel ratio, there will be almost no fluctuation in the air-fuel ratio.
In the past, however, as explained above, when the feedback control coefficient exceeded a set range, the feedback control coefficient was returned to a set range about 1.0. That is, for example, even when the amount of purge was small and therefore the concentration of fuel vapor was high, the feedback control coefficient was returned to within the set range around 1.0. Therefore, when an acceleration operation was performed from this state and the amount of purge increased, the concentration of fuel vapor widely fell, so the feedback control coefficient was increased from near 1.0 to maintain the air-fuel ratio at the stoichiometric air-fuel ratio. At this time, however, since the amount of fluctuation of the concentration of fuel vapor is large, the feedback control coefficient reaches the allowable limit of fluctuation and can no longer increase any further. That is, the feedback control coefficient is made not to be able to increase up to where the air-fuel ratio becomes the stoichiometric air-fuel ratio. As a result, the air-fuel ratio becomes considerably lean and therefore a good acceleration operation cannot be obtained. Not only this, but there is also the problem that the exhaust emission deteriorates.
A similar situation occurs even when the amount of purge is reduced as at the time of deceleration operation. That is, even when the amount of purge is large and the concentration of the fuel vapor is low, the feedback control coefficient is returned to within the set range near 1.0. Therefore, if a deceleration operation is performed from this state and the amount of purge is reduced, the concentration of the fuel vapor is greatly increased, so the feedback control coefficient ends up falling from near 1.0 to maintain the air-fuel ratio at the stoichiometric air-fuel ratio. At this time, however, the amount of fluctuation of the concentration of the fuel vapor is large, so the feedback control coefficient reaches the allowable limit of fluctuation and then can no longer fall further. That is, the feedback control coefficient cannot become small enough so that the air-fuel ratio is made the stoichiometric air-fuel ratio. As a result, the air-fuel ratio becomes considerably rich and therefore the problem arises that the exhaust emission deteriorates.
On the other hand, the air-fuel ratio does not only fluctuate when a large amount of evaporated fuel is produced in the fuel tank as explained above. The air-fuel ratio also fluctuates widely due to changes in the state of driving of the vehicle.
That is, in an internal combustion engine designed so as to control the purge rate of the fuel vapor to become a predetermined target purge rate, for example, as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 6-146965, when the air-fuel ratio deviates from the target air-fuel ratio, the calculated value of the concentration of the fuel vapor is updated by exactly a predetermined set amount without regard to the purge rate and the amount of fuel injection is corrected bared on the updated concentration of the fuel vapor so that the air-fuel ratio becomes the target air-fuel ratio.
When the air-fuel ratio deviates from the target air-fuel ratio in this way, however, if the concentration of the fuel vapor is updated by exactly a predetermined set amount without regard to the purge rate in this way, in particular when the purge rate becomes larger from a small state, the problem arises that the air-fuel ratio ends up deviating from the target air-fuel ratio.
That is, the air-fuel ratio does not fluctuate due to just the effect of the purge action. It also fluctuates due to the change in the state of driving of the vehicle. Accordingly, if the deviation of the air-fuel ratio is considered to be due entirely to the effect of the purge action and the amount of deviation of the air-fuel ratio is reflected back into the update value of the concentration of fuel vapor, the concentration of fuel vapor which is calculated will end up deviating from the actual concentration of fuel vapor. If the concentration of fuel vapor which is calculated deviates from the actual concentration of the vapor in this way, there will be no problem when the purge rate does not change or the purge rate becomes smaller, but there will be a problem when the purge rate becomes larger than a small value.
That is, for example, assume that the air-fuel ratio deviates by 2 percent from the target air-fuel ratio due to the change in the state of driving of the vehicle, not the effect of the purge action, and that the purge rate is a small value, for example, 0.5 percent. At this time, if the deviation of the air-fuel ratio is considered to be all due to the effect of the purge action and the amount of deviation of the air-fuel ratio is reflected back into the update value of the concentration of the fuel vapor, the vapor concentration which is calculated will end up deviating by 4 percent per unit purge rate (2%/0.5%) with respect to the actual concentration of the vapor. In this case, if the purge rate is maintained at 0.5 percent, the calculated vapor concentration will continue to deviate by 2 percent from the actual vapor concentration.
If the purge rate increases, however, for example, if the purge rate rises from 0.5 percent to 5 percent, the amount of deviation of the calculated vapor concentration becomes 20 percent (4% amount of deviation per unit purges rate x purge rate 5%). If the amount of deviation of the vapor concentration calculated becomes 20 percent, the amount of fuel supplied corrected based on the calculated vapor concentration will deviate considerably from the amount of fuel supply necessary for maintaining the target air-fuel ratio and therefore the problem will arise of the air-fuel ratio deviating considerably from the target air-fuel ratio.
On the other hand, when the air-fuel ratio deviates by 2 percent from the target air-fuel ratio due to the effect of the state of driving of the vehicle and the purge rate is a large value, for example, 5 percent, the vapor concentration which is calculated will be only 0.4 percent per unit purge rate (2%/5%). Therefore, at this time, there is little error in the vapor concentration and no particular problem. Further, when the purge rate falls from this state, the amount of deviation of the concentration of vapor will gradually become smaller, so there will be no particular problem in this case as well. Accordingly, a problems occurs only when updating the concentration of the fuel vapor when the purge rate is low.

Evaporated fuel treatment device of engine