An anonymous vehicular broadcast system that has encrypted links between the roadway infrastructure and the vehicles. The vehicles each have a common private key that is generated from a certification key, provided by a certification authority, and a configuration key that is generated at each power up of the vehicle. The configuration key is not stored in the vehicle so that the vehicle is only stores a portion of the private key.

A vehicle-to-vehicle and vehicle-to-infrastructure wireless communication system creates a large number of potential uses that include crash avoidance, communications, law enforcement, and entertainment. One such system is the Dedicated Short Range Communications (DSRC). This system can include a common message set, broadcast by each vehicle, that is comprised of relevant kinematical and location information including GPS/vehicle position, velocity, vehicular dimensions, as well as other relevant vehicle information.
For a typical crash avoidance system, a vehicle would analyze any received information, determine if a crash was imminent, send a confirmation message to the other vehicle, and exchange information with vehicle sub-systems to mitigate vehicle/occupant damage/injury before crashing. For example, once the accident seems likely, the vehicle sub-systems such as airbags and seatbelts can be instructed to prepare for a crash.

Security for anonymous vehicular broadcast messages

Nissan Technical Center North America, Inc.


Disclosed are a lithographic printing plate precursor that can record images by laser beam scanning exposure based on digital signals and can be printed by easy development processing or development processing on a printing machine, comprising a support having thereon an ink-receptive light-heat conversion layer containing a compound converting laser light to heat and a hardened hydrophilic layer in this order, wherein a part of said light-heat conversion layer remains at a laser light-irradiated area of the lithographic printing plate precursor, and a plate-making method of a lithographic printing plate using the same.

The present invention relates to a lithographic printing plate precursor, and particularly to a novel lithographic printing plate precursor from which a printing plate can be easily prepared and a plate-making method of a lithographic printing plate using the same. More particularly, the invention relates to a lithographic printing plate precursor that can record images by laser beam scanning exposure based on digital signals and can be printed by easy development processing or development processing on a printing machine (i.e., a printing press), and a plate-making method of a lithographic printing plates using the same.
In general, lithographic printing plate precursors comprise lipophilic image areas receiving ink in the printing process and hydrophilic non-image areas receiving fountain solution. As such lithographic printing plate precursors, presensitized plates have hitherto been widely used in which lipophilic light-sensitive resin layers are formed on hydrophilic supports. In plate-making methods thereof, after exposure through images of lithographic films, the non-image areas are usually removed by dissolving them in developing solutions, thereby obtaining desired printing plates.
The process for making the conventional presensitized plates requires the operation of removing the non-image areas by dissolution after exposure, and it is one problem that has been desired to be improved with respect to the prior art to make unnecessary or simplify such additional wet treatment. In particular, the disposal of waste liquid discharged by the wet treatment has recently become a matter of concern in the whole industry from the consideration to the earth circumstances, so that a request for an improvement in this respect has become stronger.
As one of easy plate making methods meeting this request, a method is proposed in which such image recording layers that the non-image areas of the printing plate precursors can be removed in the usual printing process are used and developed on a printing machine after exposure to obtain final printing plates. The plate-making system of the lithographic printing plates by such a method is called an xe2x80x9con-machine (i.e., on-press) development systemxe2x80x9d. Specific examples thereof include the use of image recording layers soluble in fountain solutions or ink solvents and mechanical removal of image recording layers by contact with an impression cylinder or a blanket cylinder in the printing machine. However, a large problem of the on-machine development system is that it is necessary to employ, for example, a troublesome method of keeping the printing plate precursors in a completely light-shielded state or under constant-temperature conditions until the precursors are mounted on the printing machine, because the image recording layers of the precursors are not fixed even after exposure.
On the other hand, as another recent trend in this field, digitizing techniques of electronically processing, accumulating and outputting image information by the use of computers have been widely applied, and various new image output systems corresponding to such digitizing techniques have come in practice. Associated therewith, computer-to-plate techniques have been noted in which high convergent radiations such as laser beams bear digitized image information, and printing plate precursors are subjected to scanning exposure to the radiations, thereby directly produce printing plates through no lithographic films. Resulting therefrom, it becomes an important technical problem to obtain printing plate precursors adapted to this object.
Accordingly, simplification, conversion to a dry system and dispensing with treatment of the plate-making operation have been desired more strongly than before, from both the above-mentioned circumstance problem and adaption to digitizing.
Recently, solid lasers such as semiconductor lasers and YAG lasers, which are high in output, have become available at low cost. Accordingly, the prospects for the plate-making methods using these lasers as image recording means have become particularly encouraging, as another one of the methods for producing the printing plates by scanning exposure that can be easily incorporated in the digitizing technique. In the conventional plate-making methods, low- to medium-illuminance imagewise exposure is given to light-sensitive printing plate precursors to carry out image recording according to imagewise physical property changes of precursor faces by the photochemical reaction. However, in the methods using high power density exposure using high output lasers, exposure regions are intensively irradiated with a large amount of light energy during momentary exposure time to efficiently convert light energy to heat energy, and chemical changes, phase changes and physical changes such as changes in shape or structure are allowed to occur by that heat to utilize those changes for image recording. That is to say, although image information is inputted by light energy of laser light, image recording is conducted by the reaction due to heat energy. Usually, the recording system utilizing heat generation caused by such high power density exposure is called heat-mode recording, and conversion of light energy to heat energy is called light-heat conversion.
The great advantage of the plate-making methods using heat-mode recording means is that the precursors are not sensitive to light of the usual illuminance level such as room illumination, and that fixing is not indispensable to images recorded by high illuminance exposure. That is to say, when heat-mode light-sensitive materials are used in image recording, they are safe to room light before exposure, and the fixing of images is not indispensable also after exposure. Accordingly, when the plate-making process of using, for example, image recording layers insolubilized or solubilized by heat-mode exposure, and removing the exposed image recording layers imagewise to form printing plates is carried out by the on-machine development system, such printing systems that images are not influenced by development (removal of non-image areas) for a certain period of time after image exposure, for example, even if exposed to room environmental light, become possible.
It is therefore expected that the use of the heat-mode recording will make it possible to obtain lithographic printing plate precursors desirable for the on-machine development system.
WO94/18005 discloses lithographic printing plate precursors comprising supports having provided thereon hydrophilic cross-linked layers and recording layers and the plate making of which can be similarly carried out without development. In these printing plate precursors, it is necessary to scrape away substantially all of the hydrophilic layers and recording layers of laser-exposed areas to expose surfaces of the ink-receptive supports or ink-receptive layers under the recording layers, which is considered to raise problems with regard to simplicity of processing and ink consumption in printing.
The plate-making and printing methods utilizing the heat-mode image recording have advantages that printing plates can be directly produced from camera-ready copies through no films, so that the plate making on the machine is also possible and the development operation is also dispensable. However, they have weak points such as the above-mentioned insufficient heat-mode sensitivity, the difference in sensitivity between the surfaces and bottom portions of the image recording layers, the complexity of multiple constituting layers and the insufficient discrimination between the image areas and the non-image areas. Accordingly, the requests of the market requiring lithographic printing plate precursors in which the advantages of the plate-making and printing methods of the heat-mode image recording system are utilized and both the print quality and the printing durability are improved, are not sufficiently satisfied yet in the present circumstances.
It is therefore an object of the invention to overcome the above-mentioned defects of the heat-mode plate-making system, and namely, to provide a lithographic printing plate precursor in which scanning exposure of an image to laser light for a short period of time is possible, which can be operated by easy water development processing or can be directly mounted on a printing machine, requiring no development processing, to conduct plate making, and which is excellent in printing durability, also gives few print stains onto a printed face and has good image reproducibility.
Another object of the invention is to provide a plate-making method of a lithographic printing plate using the lithographic printing plate precursor.
For attaining the objects described above, the present inventors have made search for the constitution increasing the discrimination action between image areas and non-image areas and also having characteristics necessary for printing plates such as stain resistance and printing durability. As a result, the inventors have discovered that the above-mentioned objects can be attained by providing an ink-receptive light-heat conversion layer containing a compound converting laser light to heat and a hardened hydrophilic layer on a support, cross-linking the light-heat conversion layer, and further limiting the range of the coated dry weight of the light-heat conversion layer, thus completing the invention.
That is to say, the invention is as follows:
(1) A lithographic printing plate precursor comprising a support having thereon an ink-receptive light-heat conversion layer containing a compound converting laser light to heat and a hardened hydrophilic layer in this order, wherein a part of the light-heat conversion layer remains at a laser light-irradiated area of the lithographic printing plate precursor;
(2) The lithographic printing plate precursor described in (1), wherein the light-heat conversion layer has a cross-linked structure and is hardened;
(3) The lithographic printing plate precursor described in (1) or (2), wherein the light-heat conversion layer has a dry weight of 0.5 g/m2 to 3 g/m2; and
(4) A method for producing a lithographic printing plate comprising conducting heat-mode imagewise exposure to the lithographic printing plate precursor described in any one of (1) to (3) by laser light irradiation, and during or after the laser light irradiation, removing the hydrophilic layer of the laser light-irradiated area, thereby forming an image of the ink-receptive light-heat conversion layer.
In the invention, laser light energy used for recording is absorbed by the light-heat conversion layer and converted to heat energy to cause chemical reactions or physical changes such as combustion, fusion, decomposition, vaporization and explosion, resulting in a reduction in adhesion between the light-heat conversion layer and the hydrophilic layer. Accordingly, the hydrophilic layer can be selectively easily removed, and the remaining light-heat conversion layer is removed to function as an ink-receptive layer.
In particular, the inventors have discovered that the effects are more strongly exhibited by allowing the light-heat conversion layer to have a cross-linked structure, and adjusting the light-heat conversion layer so as to have a coated dry weight ranging from 0.5 g/m2 to 3 g/m2, because the light-heat conversion layer remains at the exposed area.
As described above, the invention can provide the lithographic printing plate precursor in which heat-mode image exposure with laser light is possible, which can be operated by easy water development processing or can be directly mounted on a printing machine, requiring no development processing, to conduct plate making, and which is excellent in printing durability, also gives few print stains onto a printed face and has good image reproducibility; and the plate-making method of the lithographic printing plate using the same.
The invention will:be described in detail below.
The lithographic printing plate precursor comprises the support having provided thereon the ink-receptive light-heat conversion layer containing the compound converting laser light to heat (also called a light-heat conversion agent), and the hardened hydrophilic layer provided on the light-heat conversion layer.
[Light-Heat Conversion Layer]
The light-heat conversion layer used in the invention is a layer having the function of converting laser light used for writing to heat (light-heat conversion) and further remaining at a laser light-irradiated area to function as an ink-receptive layer, and comprises at least (1) a light-heat conversion agent and (2) a binder polymer.
Further, for remaining at the laser-irradiated area after laser exposure and removal of the laser-exposed area of the hydrophilic layer and functioning as the ink-receptive layer, the light-heat conversion layer of the invention is preferably hardened with a cross-linking agent.
(1) The light-heat conversion agents used in the invention include organic pigments such as acidic carbon black, basic carbon black, neutral carbon black, carbon black surface-modified or surface-coated for improving its dispersibility and Nigrosine pigments; organic dyes such as compounds described in Matsuoka, Infrared Sensitizing Dyes, Plenum Press, New York (1990), U.S. Pat. No. 4,833,124, EP-A-321,923, U.S. Pat. Nos. 4,772,583, 4,942,141, 4,948,776, 4,948,777, 4,948,778, 4,950,639, 4,912,083, 4,952,552 and 5,023,229; metals or metal oxides such as aluminum, indium tin oxide, tungsten oxide, manganese oxide and titanium oxide. Besides, conductive polymers such as polypyrrole and polyaniline can also be used. The amount thereof used is from 5% to 50% by weight, preferably from 8% to 45% by weight, and more preferably from 10% to 40% by weight, based on the total solid weight of light-heat conversion layer.
As (2) the binder polymers used in the invention, well-known polymers having film forming ability and dissolving or dispersing the light-heat conversion agents are used. Examples thereof include cellulose and cellulose derivatives such as nitrocellulose and ethyl cellulose; homopolymers and copolymers of acrylic esters and methacrylic esters such as polymethyl methacrylate and polybutyl methacrylate; polystyrene and homopolymers or copolymers of styrenic monomers such as xcex1-methylstyrene; various synthetic rubbers such as isoprene rubber and styrene-butadiene rubber; homopolymers of vinyl esters such as polyvinyl acetate and copolymers thereof such as vinyl acetate-vinyl chloride copolymers; various condensation polymers such as polyureas, polyurethanes, polyesters and polycarbonates; and binders used in a so-called xe2x80x9cchemical amplification systemxe2x80x9d, described in Frechet et al., J. Imaging Sci., 30(2), 59-64 (1986), Ito and Willson, Polymers in Electronics (Symposium Series), 11,242, T. Davidson, Ed., ACS Washington, D.C. (1984), and E. Reichmanis and L. F. Thompson, Microelectronic Engineering, 13, 3-10 (1991).
Of these, polymers having functional groups usable in the cross-linking reaction for hardening the light-heat conversion layers by cross-linking are preferred.
Preferred examples of the functional groups include xe2x80x94OH, xe2x80x94SH, xe2x80x94NH2, xe2x80x94NHxe2x80x94, xe2x80x94COxe2x80x94NH2, xe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94Oxe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94NHxe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94COxe2x80x94OH, xe2x80x94COxe2x80x94Oxe2x80x94, xe2x80x94COxe2x80x94Oxe2x80x94,: xe2x80x94CSxe2x80x94OH, xe2x80x94COxe2x80x94SH, xe2x80x94CSxe2x80x94SH, xe2x80x94COxe2x80x94Oxe2x80x94COxe2x80x94, xe2x80x94SO3H, xe2x80x94SO2(Oxe2x88x92), xe2x80x94PO3H2, xe2x80x94PO(Oxe2x88x92)2, xe2x80x94SO2xe2x80x94NH2, xe2x80x94SO2xe2x80x94NHxe2x80x94, xe2x80x94COxe2x80x94CH2xe2x80x94COxe2x80x94, xe2x80x94CH=CHxe2x80x94, xe2x80x94CH=CH2, :xe2x80x94COxe2x80x94CH=CH2, xe2x80x94COxe2x80x94C(CH3)=CH2 and the following functional groups.
In particular, hydroxyl, amino, carboxyl, epoxy and polymerizable vinyl groups are preferred.
Preferred examples of the binder polymers of the invention include homopolymers or copolymers of carboxyl group-containing monomers such as acrylic acid and methacrylic acid; homopolymers or copolymers of hydroxyl group-containing acrylic or methacrylic esters such as hydroxyethyl methacrylate and 2-hydroxypropyl acrylate; homopolymers or copolymers of epoxy group-containing acrylic or methacrylic esters such as glycidyl methacrylate; homopolymers or copolymers of N-alkylacrylamides and acrylamide; homopolymers or copolymers of reaction products of amines and glycidyl acrylate, glycidyl methacrylate or allylglycidyl; homopolymers or copolymers of p-hydroxystyrene and vinyl alcohol; and condensation products such as polyurethane resins, polyurea resins, polyamide (nylon) resins, epoxy resins, polyalkyleneimines, novolak resins, melamine resins and cellulose derivatives.
These polymers may be used either alone or as a combination of two or more of them. The amount thereof used is from 20% to 90% by weight, preferably from 25% to 80% by weight, and more preferably from 30% to 75% by weight, based on the total solid weight of light-heat conversion layer.
As the cross-linking reaction used in the hardening of the light-heat conversion layers of the invention, the formation of covalent bonds by heat or light or the formation of ionic bonds with multivalent metal salts is available. In the invention, it is also possible to harden the light-heat conversion layers with well-known cross-linking agents.
The well-known cross-linking agents include multifunctional isocyanate compounds, multifunctional epoxy compounds, multifunctional amine compounds, polyol compounds, multifunctional carboxyl compounds, aldehyde compounds, multifunctional (meth)acrylate compounds, multifunctional vinyl compounds, multifunctional mercapto compounds, multifunctional metal salt compounds, polyalkoxysilane compounds, polyalkoxytitanium compounds, polyalkoxyaluminum compounds, polymethylol compounds and polyalkoxymethyl compounds. It is also possible to add well-known reaction catalysts to accelerate the reaction.
The amount of these cross-linking agents used is from 0% to 50% by weight, preferably from 3% to 40% by weight, and more preferably from 5% to 35% by weight, based on the total weight of solid contained in a coating solution for the light-heat conversion layer.
In the light-heat conversion layers of the invention, other additives can be used. These additives are added depending on various purposes, for example, for improving the mechanical strength of the light-heat conversion layers, improving the laser recording sensitivity, improving the dispersibility of dispersed materials in the light-heat conversion layers, and improving the adhesion of the light-heat conversion layers to adjacent layers such as supports and primer layers.
For example, for improving the laser recording sensitivity, it is conceivable to add well-known compounds decomposed by heating to generate gas. In this case, the laser recording sensitivity can be improved by the rapid volume expansion of the light-heat conversion layers. Examples of these additives include azidodicarbonamide, sulfonylhydrazine and dinitrosopentamethylenetetramine.
Further, well-known compounds decomposed by heating to produce acidic compounds can be used as additives. The use of them in combination with the binders of the chemical amplification system largely decreases the decomposition temperature of materials constituting the light-heat conversion layers, and as a result, the laser recording sensitivity can be improved. Examples of these additives include various kinds of iodonium salts, sulfonium salts, phosphonium tosylate, oxime sulfonate, dicarbodiimide sulfonate and triazine.
When pigments such as carbon black are used in the light-heat conversion agents, the dispersibility of the pigments sometimes have an effect on the laser recording sensitivity. Accordingly, various kinds of pigment dispersing agents are used as additives.
For improving the adhesion, well-known adhesion improvers (for example, silane coupling agents and titanate coupling agents) may be used.
In addition, various additives such as surfactants for improving coating properties are used as needed.
The compositions for the light-heat conversion layers used in the invention are dissolved or dispersed in appropriate solvents, and applied onto substrates and dried. Examples of the solvents include 2-methoxyethanol, 2-methoxyethyl acetate, propylene glycol methylethyl acetate, methyl lactate, ethyl lactate, propylene glycol monomethyl ether, ethanol, isopropanol, methyl ethyl ketone, N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran and dioxane. They may be used either alone or as a mixed solvent thereof.
The weight thereof coated is preferably from 0.5 g/m2 to 3 g/m2 by weight after drying. Less than 0.5 g/m2 gives unfavorable results such as a decrease in laser recording sensitivity and a decrease in ink receptivity, whereas exceeding 3 g/m2 results in a tendency to increase the consumption of ink, which is economically disadvantageous.
The hydrophilic layers used in the lithographic printing plate precursors of the invention will be described below.
[Hydrophilic Layer]
The hydrophilic layer used in the invention is a layer receiving and retaining;a fountain solution in printing and functioning as a non-image area, and a layer having a hardened, water-insoluble hydrophilic matrix.
Preferred examples of the hydrophilic matrixes of the hydrophilic layers used in the invention include organic hydrophilic matrixes obtained by cross-linking or pseudo cross-linking of organic hydrophilic polymers, and inorganic hydrophilic matrixes obtained by sol-gel conversion comprising the hydrolysis and condensation reaction of polyalkoxysilanes, titanates, zirconates or aluminates.
As the cross-linking reaction used in the formation of the organic hydrophilic matrixes of the hydrophilic layers of the invention, the formation of covalent bonds by heat or light or the formation of ionic bonds with multivalent metal salts is available.
As the organic hydrophilic polymers used in the invention, polymers having functional groups usable in the cross-linking reaction are preferred.
Preferred examples of the functional groups include xe2x80x94OH, xe2x80x94SH, xe2x80x94NH2, xe2x80x94NHxe2x80x94, xe2x80x94COxe2x80x94NH2, xe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94Oxe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94NHxe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94COxe2x80x94OH, xe2x80x94COxe2x80x94Oxe2x80x94, xe2x80x94COxe2x80x94Oxe2x88x92, xe2x80x94CSxe2x80x94OH, xe2x80x94COxe2x80x94SH, xe2x80x94CSxe2x80x94SH, xe2x80x94SO3H, xe2x80x94SO2 (Oxe2x88x92), xe2x80x94PO3H2, xe2x80x94PO(O31 )2, xe2x80x94SO2xe2x80x94NH2, xe2x80x94SO2xe2x80x94NHxe2x80x94 and the following functional groups.
In particular, hydroxyl, amino, carboxyl and epoxy groups are preferred.
As such organic hydrophilic polymers of the invention, well-known water-soluble polymers can be used, and examples thereof include polyvinyl alcohol (polyvinyl acetate having a degree of saponification of 60% or more), modified polyvinyl alcohol such as carboxy-modified polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as carboxymethyl cellulose, salts thereof and hydroxyethyl cellulose, casein, gelatin, gum arabic, polyvinyl-pyrrolidone, vinyl acetate-crotonic acid copolymers and salts thereof, styrene-maleic acid copolymers and salts thereof, polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, polyethylene glycol, polyethyleneimine, polyvinylsulfonic acid and salts thereof, polyhydroxyethyl methacrylate, polyhydroxyethyl acrylate and polyacrylamide.
These polymers may be used either alone or as a combination of two or more of them. The amount thereof used is from 20% to 99% by weight, preferably from 25% to 95% by weight, and more preferably from 30% to 90% by weight, based on the total solid weight of light-heat conversion layer.
In the invention, it is possible to cross-link the organic hydrophilic polymers with well-known cross-linking agents.
The well-known cross-linking agents include multifunctional isocyanate compounds, multifunctional epoxy compounds, multifunctional amine compounds, polyol compounds, multifunctional carboxyl compounds, aldehyde compounds, multifunctional (meth)acrylate compounds, multifunctional vinyl compounds, multifunctional mercapto compounds, multifunctional metal salt compounds, polyalkoxysilane compounds and hydrolyzates thereof, polyalkoxytitanium compounds and hydrolyzates thereof, polyalkoxyaluminum compounds and hydrolyzates thereof, polymethylol compounds and polyalkoxymethyl compounds. It is also possible to add well-known reaction catalysts to accelerate the reaction.
The amount thereof used is from 1% to 50% by weight, preferably from 3% to 40% by weight, and more preferably from 5% to 35% by weight, based on the total weight of solid contained in a coating solution for the light-heat conversion layer.
Sol-gel convertible systems applicable to the formation of the inorganic hydrophilic matrixes of the hydrophilic layers of the invention are polymers in which binding groups extending from multivalent elements form network structures through oxygen atoms and the multivalent metals have unbonded hydroxyl groups or alkoxyl groups at the same time to form resinous structures containing mixtures thereof. The polymers are in the sol state at a stage that there are many alkoxyl groups or hydroxyl groups, but the network resinous structures become strong with the progress of ether bonding. Further, they also have together the action that the hydroxyl groups are partly bonded to fine solid particles, thereby modifying the surfaces of the fine solid particles to change the hydrophilicity. Examples of the multivalent binding elements of compounds having the hydroxyl groups or alkoxyl groups performing the sol-gel conversion are aluminum, silicon, titanium and zirconium, which can be used in the invention. Sol-gel conversion systems due to siloxane bonds which can be most preferably used are described below. Sol-gel conversion using aluminum, titanium and zirconium can be conducted by replacing each element for silicon described below.
That is to say, particularly preferably used are systems containing silane compounds each having at least one sol-gel convertible silanol group.
The systems utilizing sol-gel conversion are further described below. Inorganic hydrophilic matrixes formed by sol-gel conversion are preferably resins having siloxane bonds and silanol groups, and hydrolysis condensation of the silanol groups progresses during coating, drying and the elapse of time of coating solutions which are sol systems containing silane compounds each having at least one silanol group to form structures of siloxane skeletons, thus forming the matrixes by the progress of gelation.
For improving physical properties such as film strength and flexibility, improving coating properties, and adjusting hydrophilicity, it is also possible to add the above-mentioned organic hydrophilic polymers and cross-linking agents to the matrixes of the gel structure.
A siloxane resin forming the gel structure is represented by the following formula (I), and a silane compound having at least one silanol group is obtained by hydrolysis of a silane compound represented by the following formula (II). Further, the silane compound having at least one silanol group is not necessarily composed of the partially hydrolyzed product of the silane compound of formula (II) alone. In general, it may be composed of either an oligomer obtained by partial hydration polymerization of the silane compound, or a mixture of the silane compound and its oligomer.
The siloxane resin of the above-mentioned formula (I) is formed by sol-gel coversion of at least one silane compound represented by the following formula (II). At least one of R01 to R03 in formula (I) represents a hydroxyl group, and the others each represents an organic residue selected from symbols R0 and Y in the following formula (II).
(R0)nSi(Y)4xe2x88x92nxe2x80x83xe2x80x83(II)
wherein R0 represents a hydroxyl group, a hydrocarbon group or a heterocyclic group; Y represents a hydrogen atom, a halogen atom (which represents a florine, chlorine, bromine or iodine atom), xe2x80x94OR1, xe2x80x94OCOR2 or xe2x80x94N(R3)(R4) (wherein R1 and R2 each represents a hydrocarbon group, and R3 and R4 , which may be the same or different, each represents a hydrogen atom or a hydrocarbon group); and n represents 0, 1, 2 or 3.
Examples of the hydrocarbon groups or the heterocyclic groups represented by formula (II) include a substituted or unsubstituted straight chain or branched alkyl group having from 1 to 12 carbon atoms (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, each of which may be substituted with at least one substituent such as a halogen atom (chlorine, fluorine, bromine), a hydroxyl group, a thiol group, a carboxyl group, a sulfo group, a cyano group, an epoxy group, an xe2x80x94ORxe2x80x2 group (wherein Rxe2x80x2 represents methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, decyl, propenyl, butenyl, hexenyl, octenyl, 2-hydroxyethyl, 3-chloropropyl, 2-cyanoethyl, N,N-dimethyl-aminoethyl, 1-bromoethyl, 2-(2-methoxyethyl)oxyethyl, 2-methoxycarbonylethyl, 3-carboxypropyl or benzyl), an xe2x80x94OCORxe2x80x3 group (wherein Rxe2x80x2 has the same meaning as Rxe2x80x2), a xe2x80x94COORxe2x80x3 group, a xe2x80x94CORxe2x80x3 group, an xe2x80x94N(Rxe2x80x2xe2x80x3) (Rxe2x80x2xe2x80x3) group (wherein Rxe2x80x2xe2x80x3 represents a hydrogen atom or the same group as Rxe2x80x2, which may be the same or different) an xe2x80x94NHCONHRxe2x80x2xe2x80x3 group, an xe2x80x94NHCOORxe2x80x3 group, an xe2x80x94Si(Rxe2x80x3)3 group, a xe2x80x94CONHRxe2x80x2xe2x80x3 group or an xe2x80x94NHCORxe2x80x3 group); a substituted or unsubstituted straight chain or branched alkenyl group having from 2 to 12 carbon atoms (e.g., vinyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, decenyl, dodecenyl, each of which may be substituted with the same substituent as described above for the alkyl groups; a substituted or unsubstituted aralkyl group having from 7 to 14 carbon atoms (e.g., benzyl, phenetyl, 3-phenylpropyl, naphthylmethyl, 2-naphthylethyl, each of which may be substituted with at least one substituent which is the same as described above for the alkyl group); a substituted or unsubstituted alicyclic group having from 5 to 10 carbon atoms (e.g., cyclopentyl, cyclohexyl, 2-cyclohexylethyl, 2-cyclopentylethyl, norbornyl, adamantyl, each of which may be substituted with at least one substituent which is the same as described above for the alkyl group); a substituted or unsubstituted aryl group having from 6 to 12 carbon atoms (e.g, phenyl, naphthyl, each of which may be substituted with at least one substituent which is the same as described above for the alkyl group); and a heterocyclic group, which may be ring-condensed, containing at least one atom selected from a nitrogen atom, an oxygen atom and a sulfur atom (examples of the heterocycles include a pyran ring, a furan ring, a thiophene ring, a morpholine ring, a pyrrole ring, a thiazole ring, an oxazole ring, a pyridine ring, a piperidine ring, a pyrrolidone ring, a benzothiazole ring, a benzoxazole ring, a quinoline ring and a tetrahydrofuran ring, each of which may be substituted with at least one substituent which is the same as described above for the alkyl group).
Substituents of an xe2x80x94ORxe2x80x2 group, an xe2x80x94OCOR2 group or an xe2x80x94N(R3)(R4) group indicated by Y in formula (II) are as follows.
In the xe2x80x94OR1 group, R1 represents a substituted or unsubstituted aliphatic group having from 1 to 10 carbon atoms (e.g, methyl, ethyl, propyl, butoxy, heptyl, hexyl, pentyl, octyl, nonyl, decyl, propenyl, butenyl, heptenyl, hexenyl, octenyl, decenyl, 2-hydroxyethyl, 2-hydroxypropyl, 2-methoxyethyl, 2-(methoxyethyloxo)ethyl, 1-(N,N-diethylamino)ethyl, 2-methoxypropyl, 2-cyanoethyl, 3-methyloxapropyl, 2-chloroethyl, cyclohexyl, cyclopentyl, cyclooctyl, chlorocyclohexyl, methoxycyclohexyl, benzyl, phenetyl, dimethoxybenzyl, methylbenzyl, bromobenzyl.
In the xe2x80x94OCOR2 group, R2represents the same aliphatic group as in R1, or a substituted or unsubstituted aromatic group having from 6 to 12 carbon atoms (e.g., the same aryl groups as described for R0).
In the xe2x80x94N(R3) (R4) group, R3 and R4, which may be the same or different, each represents a hydrogen atom, or a substituted or unsubstituted aliphatic group having from 1 to 10 carbon atoms (e.g., the same groups as described above for R1 in the xe2x80x94OR1 group).
More preferably, the total carbon atoms contained in R3and R4 are 16 or less.
Specific examples of the silane compounds represented by formula (II) include but are not limited to the following compounds: tetrachlorosilane, tetrabromosilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-propylsilane, tetra(t-butoxy)silane, tetra(n-butoxy)silane, dimethoxydiethoxysilane, methyltrichlorosilane, methyltribromosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltri (t-butoxy) silane, ethyltrichlorosilane, ethyltribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltri(t-butoxy)silane, n-propyltrichlorosilane, n-propyl-tribromosilane, n-propyltrimethoxysilane, n-propyltriethoxy-silane, n-propyltriisopropoxysilane, n-propyltri(t-butoxy)-silane, n-hexyltrichlorosilane, n-hexyltribromosilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-hexyltri-isopropoxysilane, n-hexyltri(t-butoxy)silane, n-decyltri-chlorosilane, n-decyltribromosilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n-decyltriisopropoxysilane, n-decyltri(t-butoxy)silane, n-octadecyltrichlorosilane, n-octadecyl-tribromosilane, n-octadecyltrimethoxysilane, n-octadecyltri-ethoxysilane, n-octadecyl-tri(t-butoxy)silane, phenyltrichlorosilane, phenyltribromo-silane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, phenyltri(t-butoxy)silane, dimethyldichlorosilane, dimethyldibromosilane, dimethyl-dimethoxysilane, dimethyldiethoxysilane, diphenyldichloro-silane, diphenyldibromosilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenylmethyldichlorosilane, phenylmethyldibromosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane, triethoxyhydrosilane, tribromohydrosilane, trimethoxyhydrosilane, triisopropoxyhydrosilane, tri(t-butoxy)hydrosilane, vinyltrichlorosilane, vinyltribromosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyl(t-butoxy)silane, trifluoropropyltrichlorosilane, trifluoropropyltribromosilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, trifluoropropyltriisopropoxysilane, trifluoropropyltri(t-butoxy)silane, xcex3-glycidoxypropylmethyldimethoxysilane, xcex3-glycidoxypropylmethyldiethoxysilane, xcex3-glycidoxypropyltrimethoxysilane, xcex3-glycidoxypropyltriethoxysilane, xcex3-glycidoxypropyltriisopropoxysilane, xcex3-glycidoxypropyltri(t-butoxy)silane, xcex3-methacryloxypropylmethyldimethoxysilane, xcex3-methacryloxypropylmethyldiethoxysilane, xcex3-methacryloxypropyltrimethoxysilane, xcex3-methacryloxypropyltriisopropoxysilane, xcex3-methacryloxypropyltri(t-butoxy)silane, xcex3-aminopropylmethyldi-methoxysilane, xcex3-aminopropylmethyldiethoxysilane, xcex3-amino-propyltrimethoxysilane, xcex3-aminopropyltriethoxysilane, xcex3-aminopropyltriisopropoxysilane, xcex3-aminopropyltri (t-butoxy)-silane, xcex3-mercaptopropylmethyldimethoxysilane, xcex3-mercapto-propylmethyldiethoxysilane, xcex3-mercaptopropyltrimethoxysilane, xcex3-mercaptopropyltriethoxysilane, xcex3-mercaptopropyltriisopropoxysilane, xcex3-mercaptopropyltri (t-butoxy) silane, xcex2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and xcex2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.
In combination with the silane compounds represented by formula (II) for use in;the formation of the inorganic hydrophilic matrixes of the hydrophilic layers of the invention, metal compounds capable of film-forming by bonding to resins in sol-gel conversion, such as Ti, Zn, Sn, Zr and Al compounds, can be used. Examples of the metal compounds usable in combination include Ti (OR5)2 (wherein R5 is methyl, ethyl, propyl, butyl, pentyl or hexyl), TiCl4, Ti(CH3COCHCOCH3)2(OR5)2, Zn (OR5)2, Zn (CH3COCHCOCH3)2, Sn (OR5)4, Sn (CH3COCHCOCH3)4, Sn(OCOR5)4, SnCl4, Zr(OR5)4, Zr(CH3COCHCOCH3)4, Al(OR5) 3 and Al(CH3COCHCOCH3)3.
Further, it is preferred to use an acidic or basic catalyst for accelerating the hydrolysis and polycondensation reaction of the silane compound represented by formula (II) and the above-mentioned metal compound used in combination therewith.
The catalyst used for the above purpose is an acidic or basic compound as it is or dissolved in water or a solvent such as alcohol (such a compound is hereinafter referred to as an acidic catalyst or a basic catalyst, respectively). The concentration of the catalyst is not particularly restricted, but when the catalyst with high concentration is used, the hydrolysis rate and the polycondensation rate are liable to be increased. However, since the basic catalyst used in a high concentration sometimes causes precipitation in the sol solution, it is preferred that the basic catalyst concentration be not higher than 1 N (the concentration in the aqueous solution).
The kind of acid catalyst or basic catalyst is not particularly limited. Specific examples of the acid catalysts include hydrogen halides such as hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, hydrogen sulfide, perchloric acid, hydrogen peroxide, carbonic acid, carboxylic acids such as formic acid and acetic acid, substituted carboxylic acids in which R of the structural formula represented by RCOOH is substituted by another element or substituent, and sulfonic acids such as benzenesulfonic acid. Specific examples of the basic catalysts include ammoniacal bases such as aqueous ammonia and amines such as ethylamine and aniline.
Further details of the sol-gel method described above are described in the literatures such as Sumio Sakibana, xe2x80x9cScience of Sol-GelMethodsxe2x80x9d, published by Agune Shofusha (1988) and Seki Hirashima, xe2x80x9cTechniques for Preparing Functional Thin Films by the Newest Sol-Gel Methodsxe2x80x9d, published by Sogo Gijutsu Center (1992).
In addition to the above-mentioned additives, various compounds, for example, for controlling the degree of hydrophilicity, improving the mechanical strength of the hydrophilic layers, improving the mutual dispersibility of the compositions constituting the layers, improving the coating properties and improving the printability can be added to the hydrophilic layers of the invention. Examples thereof include plasticizers, pigments, dyes, surfactants and hydrophilic particles.
Although there is no particular limitation on the hydrophilic particles, preferred examples thereof include silica, alumina, titanium oxide, magnesium oxide, magnesium carbonate and calcium alginate. They can be used for enhancing the hydrophilicity and strengthening the coatings. More preferred are silica, alumina, titanium oxide and mixtures thereof.
Silica has many hydroxyl groups on its surface, and the inside thereof constitutes the siloxane bond (xe2x80x94Sixe2x80x94Oxe2x80x94Si). Silica which can be preferably used in the invention is an ultrafine silica particle having a particle size of 1 nm to 100 nm dispersed in water or a polar solvent, and also called colloidal silica. Specifically, it is described in xe2x80x9cApplication Techniques of High Purity Silicaxe2x80x9d supervised by Tosiro Kagami and Ei Hayashi, vol. 3, CMC Corporation (1991).
Further, alumina which can be preferably used is an alumina hydrate (boehmite based) having a colloid size of 5 nm to 200 nm, and one in which alumina particles are dispersed using an anion in water (for example, a halogen atom ion such as a fluorine ion or a chlorine ion, or a carboxylic acid anion such as an acetic acid ion) as a stabilizer.
Furthermore, titanium oxide which can be preferably used is anatase or rutile titanium oxide having an average primary particle size of 50 nm to 500 nm, dispersed in water or a polar solvent using a dispersing agent as needed.
In the invention, the average primary particle size of the hydrophilic particles which can be preferably used is from 1 nm to 5000 nm, and preferably from 10 nm to 1000 nm.
In the hydrophilic layers of the invention, these hydrophilic particles may be used either alone or as a combination of two or more kinds of them. The amount thereof used is from 5% to 80% by weight, preferably from 10% to 70% by weight, and more preferably from 20% to 60% by weight, based on the total solid weight of hydrophilic layer.
The compositions for the hydrophilic layers used in the invention are dissolved or dispersed in appropriate solvents, for example, water or polar solvents such as methanol and ethanol, and applied onto the light-heat conversion layers, dried and hardened. The solvents may be used either alone or as a mixed solvent thereof.
The weight thereof coated is suitably from 0.1 g/m2 to 20 g/m2, preferably from 0.3 g/m2 to 10 g/m2, and more preferably from 0.5 g/m2 to 5 g/m2, by weight after drying. Less than 0.1 g/m2 gives unfavorable results such as a reduction in fountain solution retaining ability and a decrease in film strength, whereas exceeding 20 g/m2 results in a tendency to increase the consumption of ink, which is economically disadvantageous.
The supports used in the lithographic printing plate precursors of the invention are required to have such flexibility that they can be set on an ordinary printing machine and withstand the load imposed in printing at the same time. Accordingly, typical examples of the supports include coated paper, metal plates such as aluminum plates, plastic films such as polyethylene terephthalate films, and rubber or composite materials thereof. More preferred are aluminum plates, aluminum-containing alloy plates (for example, plates of alloys of aluminum with metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth and nickel) and plastic films. The thickness of the support is suitably from 25 xcexcm to 3 nm, and preferably from 75 xcexcm to 500 xcexcm. However, it varies depending on the kind of support used and the printing conditions. In general, it is most preferably from 100 xcexcm to 300 xcexcm.
In the lithographic printing plate precursor of the invention, the support can be subjected to surface treatment such as corona treatment, or a primer layer can be provided between the support and the light-heat conversion layer, for improving the adhesion between the support and the light-heat conversion layer and improving the printability. The primer layers used in the invention include, for example, layers of various photosensitive polymers exposed and hardened before lamination with photosensitive resin layers as disclosed in JP-A-60-22903 (the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d), layers of heat-cured epoxy resins disclosed in JP-A-62-50760, layers of hardened gelatin disclosed in JP-A-63-133151, layers using urethane resins and silane coupling agents disclosed in JP-A-3-200965 and layers using urethane resins disclosed in JP-A-3-273248. In addition, a layer obtained by hardening gelatin or casein is also effective. Further, for softening the primer layers, polymers whose glass transition temperature is lower than room temperature may be added to the primer layers. Such polymers include polyurethanes, polyamides, styrene/butadiene rubber, carboxy-modified styrene/butadiene rubber, acrylonitrile/butadiene rubber, carboxy-modified acrylonitrile/butadiene rubber, polyisoprene, acrylate rubber, polyethylene, chlorinated polyethylene and chlorinated polypropylene. The polymers may be added in any amount, and the primer layers may be formed by the polymers alone, as long as the amount thereof is within the range of being able to form film layers. Further, the primer layers can also contain additives such as dyes, pH indicators, printing-out agents, photopolymerization initiators, adhesion aids (for example, polymerizable monomers, diazo resins and silane coupling agents), pigments, silica powder and titanium oxide powder, answering the above-mentioned purposes. Further, the primer layers can also be hardened by exposure after coating. In general, the amount of the primer layer coated is suitably from 0.1 g/m2 to 10 g/m2, preferably from 0.3 g/m2 to 8 g/m2, and more preferably from 0. 5 g/m2 to 5 g/m2, by weight after drying.
In the lithographic printing plate precursor of the invention, a hydrophilic protective layer may be formed on the hydrophilic layer, for the purpose of protecting the surface hydrophilicity of the hydrophilic layer. It is preferred that the hydrophilic protective layer is easily removed with water or a fountain solution. The hydrophilic protective layers can be provided by applying and drying water-soluble polymers such as polyvinyl alcohol (polyvinyl acetate having a degree of saponification of 60% or more), modified polyvinyl alcohol such as carboxy-modified polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as carboxymethyl cellulose, salts thereof and hydroxyethyl cellulose, casein, gelatin, gum arabic, polyvinylpyrrolidone, vinyl acetate-crotonic acid copolymers, styrene-maleic acid copolymers, polyacrylic acid and salts thereof, polymethacrylic acid and salts thereof, polyethylene glycol and polyethyleneimine. In this case, the dry weight of the hydrophilic protective layer is preferably from 0.01 g/m2 to 5 g/m2, and more preferably from 0.05 g/m2 to 2 g/m2.
In the invention, laser light energy used for recording is absorbed by the light-heat conversion layer of the lithographic printing plate precursor of the invention and converted to heat energy to cause chemical reactions or physical changes such as combustion, fusion, decomposition, vaporization and explosion at a part of the light-heat conversion layer, resulting in a reduction in adhesion between the light-heat conversion layer and the hydrophilic layer. Only the occurrence of the above-mentioned changes at a part of a surface of the light-heat conversion layer suffices for reducing the adhesion between the light-heat conversion layer and the hydrophilic layer, which is advantageous also in sensitivity. It becomes unnecessary to provide a primer layer (a layer under the light-heat conversion layer) for giving the function as an ink-receptive layer or preventing heat energy from being scattered and lost by heat conduction.
In the invention, laser light is used for exposing the lithographic printing plate precursors. There is no particular limitation on lasers used, as long as they provide exposure necessary for causing a reduction in adhesion enough to remove the hydrophilic layers. Gas lasers such as Ar lasers and carbon dioxide lasers, solid lasers such as YAG lasers, and semiconductor lasers can be used. Usually, lasers having an output of 50 mW or more are required. In practical respects of maintenance and cost, semiconductor lasers and semiconductor-excited solid lasers (such as YAG lasers) are suitably used. The recording wavelength of these lasers is within the range of infrared wavelength, and an oscillating wavelength of 800 nm to 1100 nm is utilized in many cases. Further, it is also possible to expose the lithographic printing plate precursors, using an imaging apparatus described in JP-A-6-186750.
For the lithographic printing plate precursors of the invention laser-exposed by the above-mentioned methods, the hydrophilic layers of laser-exposed areas (image areas) may be removed during laser exposure, and are removed after laser exposure if necessary to expose the remaining light-heat conversion layers acting as ink-receptive areas.
The hydrophilic layers of laser-exposed areas (image areas) are removed, for example, by suction, pressing contact and separation of adhesive tapes, or rubbing precursor surfaces with rubbing members such as pads for development and brushes for development in the presence or absence of processing solutions.
The processing solutions used in the invention are preferably water or aqueous solutions mainly composed of water, from the viewpoints of safety, inflammability and retaining of surface hydrophilicity of the hydrophilic layers. Only water (city water, pure water or distilled water) and aqueous solutions of surfactants (anionic, cationic and nonionic) can be used.
Further, examples of solvents usable in the processing solutions of the invention include, for example, aliphatic hydrocarbons (such as hexane, heptane, xe2x80x9cIsopar E, H, Gxe2x80x9d manufactured by Esso Kagaku K. K., gasoline and Kerosine), aromatic hydrocarbons (such as toluene and xylene), halogenated hydrocarbons (such as trichlene) and the following polar solvents.
Examples of the polar solvents include, for example, alcohols (such as methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol and tetraethylene glycol); ketones (such as acetone and methyl ethyl ketone); esters (such as ethyl acetate, methyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, diethylene glycol acetate and diethyl phthalate); and others (such as triethyl phosphate and tricresyl phosphate).
It is also possible to add water to the organic solvent processing solutions, or to solubilize the organic solvents in water using surfactants. When the processing solution contains the solvent, the concentration of the solvent is desirably less than 40% by weight.
Further, the processing solutions containing alkaline agents (for example, sodium carbonate, triethanolamine, diethanolamine, sodium hydroxide and silicates) or acidic agents (for example, phosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, oxalic acid, malic acid, tartaric acid, boric acid and amino acids) can also be used.
The processing solutions can be used at any temperature, preferably at a temperature of 10xc2x0 C to 50xc2x0 C.
The hydrophilic layers of laser-exposed areas can also be removed, for example, by mounting the laser-exposed printing plates on a plate cylinder of a printing machine, and bringing the printing plates into contact with an application roller of a fountain solution and/or ink on the printing machine.

Lithographic printing plate precursor and plate-making method of lithographic printing plate using the same


A frame for a die casting machine, including a first side, a second side, a toggle endpiece and a die endpiece opposite the toggle endpiece, one of the first and second sides having an upper frame member with a die end and a toggle end, the die end being releasably secured to the die endpiece, and a lower frame member integrally joined to the die endpiece and the toggle endpiece, the other of the first and second sides having upper and lower frame members integrally joined to the die and toggle endpieces.

The present invention relates generally to die casting machines, and specifically to such a machine made with a one piece frame for supporting the dies as well as the pressurized die clamping mechanism.
Die casting dies are used for making die castings and are usually composed of two structures that can be moved relative to each other to create the shape of a casting enclosed between them. Also, dies can be moved relative to the casting to enable removal of the casting upon formation. However, in some cases a casting cannot be formed using only two casting members, and an additional component is required, known as a core slide. The structure of the core slide, which includes a hydraulic core pulling cylinder, often extends beyond the "die space" and actually beyond the exterior dimensions of the die casting machine.
Die casting machines typically have long working lives, and this certainly applies to such machines manufactured by the Lester Engineering Company of Cleveland, Ohio. These so-called Lester machines, which are disclosed in U.S. Pat. No. 2,411,999, include an upper frame which is a one piece casting. The upper frame provides structural support for the hydraulic toggle mechanism which clamps the two dies together, as well as providing support for the dies themselves.
Originally built in the 1940's, the Lester machines established a reputation for durability and reliable operation due in part to the strong upper frame. The one piece upper frame construction not only provides substantial support for the 600,000 pounds of pressure generated by the clamping mechanism, but also maintains the alignment of the dies for higher quality castings.
Despite the advantages of Lester machines, their main advantage, the solid frame, is also their main disadvantage in the modern factory environment, especially where Just-In-Time manufacturing strategies are used. At the time the Lester machine was designed, operators would typically run a set of dies for a relatively long period of time between die changeovers. Thus, the time involved to make die changeovers was not considered a significant factor affecting manufacturing efficiency. In contrast, many modern factories need to change their dies on a more frequent basis, and in some cases several changes a day are required.
For dies which have several side core pulling cylinders, changeover in a Lester machine is a tedious process. This is because the side core pulling cylinders project beyond the fixed frame members in several directions. As such, the cylinders and dies cannot be removed as a unit without the cylinders becoming hung up on the frame. Thus, in the Lester machines, each time a die change must be performed, the core pulling cylinders must be disassembled before the dies can be pulled from the frame. Such die changes can take as long as 8 to 12 hours to complete.
Another disadvantage of dismantling the die set is that adjustments are often required to the core slide after it has been reassembled to the die to ensure that the castings produced are dimensionally correct. This adjustment is performed after at least one casting is made and measured. These adjustments further extend the time that a die casting machine is out of production for a die change.
More modern die casting machines have upper frames with movable rod-like upper frame members which slide linearly under either manual or automatic control away from the die area to permit the dies and core pulling cylinders to be removed as a unit. A major advantage of these more modern machines is that the replacement die set can be fully assembled prior to the change and be waiting at the machine for the removal of the previous die set. However, and keeping in mind the major advantage of the Lester machines with their solid frame, a significant design and operational problem of more modern die casting machines is that the newer frames must be specially built so that the movable frame members can be secured against the substantial clamping forces necessary in the die casting process, while maintaining accurate alignment of the dies. These modern frames are inherently less rigid than the Lester machines, and are consequently less accurate than the one piece frame type machines.
Accordingly, it is a principal object of the present invention to provide a modification for a one piece frame die casting machine which permits rapid changeovers of die sets having multiple core pulling cylinders.
Another object of the present invention is to provide a modification for a Lester type die casting machine which permits the temporary displacement of at least one frame member to permit the rapid exchange of die sets without requiring disassembly of the core pulling cylinders.
Yet another object of the present invention is to provide a mechanism for a Lester type die casting machine which accurately locates a displaceable frame member in position on the frame after exchange of die sets, and which also securely retains the frame member to the frame to withstand the significant clamping forces without causing misalignment of the dies.
Still another object of the present invention is to provide a mechanism for the conversion of a one piece frame type of die casting machine to permit rapid changes of die sets complete with core pulling cylinders, at a fraction of the cost of replacing the existing machine with a new die casting machine.


A detection apparatus and method for FMCW LIDAR employ signals whose frequencies are modified so that low-cost and low-speed photodetector arrays, such as CCD or CMOS cameras, can be employed for range detection. The LIDAR is designed to measure the range z to a target and includes a single mode swept frequency laser (SFL), whose optical frequency is varied with time, as a result of which, a target beam which is reflected back by the target is shifted in frequency from a reference beam by an amount that is proportional to the relative range z to the target. The reflected target beam is combined with the reference beam and detected by the photodetector array. By first modulating at least one of the target and reference beams such that the difference between the frequencies of the reflected target beam and the reference beam is reduced to a level that is within the bandwidth of the photodetector array, the need for high-speed detector arrays for full-field imaging is obviated.

1. Field of the Invention
The present invention relates in general to a full-field three-dimensional imaging apparatus and method using a tomographic imaging camera in conjunction with a swept-frequency laser source. This approach is based on the one-shot acquisition of entire two-dimensional (2-D) (x,y) tomographic slices (with a fixed z) at very fast speeds, but uses readily available low-speed detector arrays such as CCD or CMOS cameras.
2. Description of the Background Art
Frequency modulated continuous wave (FMCW) reflectometry has emerged as a very important technique in a variety of applications including LIDAR [1], biomedical imaging [2, 3], biometrics [4], and non-contact profilometry [5]. This is due to unique advantages of the FMCW approach such as a high dynamic range and simple data acquisition that does not require high-speed electronics [6]. The basic principle of FMCW LIDAR is as follows. The optical frequency of a single mode laser is varied linearly with time, with a slope ξ. The output of the laser impinges on a target and the reflected signal is mixed with a part of the laser output in a photodetector (PD). If the relative delay between the two light paths is τ, the PD output is a sinusoidal current with frequency ξτ. The distance to the target (or "range") τ is determined by taking a Fourier transform of the detected photocurrent. Reflections from multiple targets at different depths result in separate frequencies in the photocurrent.
The important metrics of an FMCW system are the linearity of the swept source—a highly linear source eliminates the need for post-processing of acquired data—and the total chirp bandwidth B which determines the range resolution. A high-resolution FMCW LIDAR or imaging system has two important components: i) a broadband swept-frequency laser (SFL) for high axial resolution; and ii) a technique to translate the one-pixel measurement laterally in two dimensions to obtain a full 3-D image.
State of the art SFL sources for biomedical and other imaging applications are typically mechanically tuned external cavity lasers where a rotating grating tunes the lasing frequency [2, 7, 8]. Fourier-domain mode locking [9] and quasi-phase continuous tuning [10] have been developed to further improve the tuning speed and lasing properties of these sources. However, all these approaches suffer from complex mechanical embodiments that limit their speed, linearity, coherence, size, reliability and ease of use and manufacture.
Detectors for 3-D imaging typically rely on the scanning of a single pixel measurement across the target to be imaged [11]. This approach requires a complex system of mechanical scanning elements to precisely move the optical beam from pixel to pixel, which severely limits the speed of image acquisition. It is therefore desirable to eliminate the requirement for mechanical scanning, and obtain the information from the entire field of pixels in one shot. To extend the FMCW technique to a detector array, the frequencies of the photocurrents from each detector in the array should be separately calculated. However, in a high-axial-resolution system, each detector in the array measures a beat signal typically in the MHz regime. A large array of high speed detectors therefore needs to operate at impractical data rates (˜THz) and is prohibitively expensive. For this reason, there are no practical full-field FMCW LIDAR imaging systems, except some demonstrations with extremely slow scanning rates [4, 11] or expensive small arrays [12].
An ideal FMCW LIDAR system will therefore consist of a broadband rapidly tuned SFL, and a detection technique that is capable of measuring the lateral extent of the object in one shot. The system will be inexpensive, robust, and contain no moving parts.
Previously, a novel optoelectronic SFL source has been developed [13] based on the tuning of the frequency of a semiconductor laser via its injection current. Using a combination of open loop predistortion and closed loop feedback control of the laser current, the SFL generates extremely linear and broadband optical chirps. The starting frequency and slope of the optical chirp are locked to, and determined solely by, an electronic reference oscillator—they are independent of the tuning characteristics of the laser. Chirp bandwidths of 1 THz at chirp speeds exceeding 1016 Hz/s have been demonstrated, and it has been shown that arbitrary optical chirp shapes can be electronically generated. The optoelectronic SFL source is compact and robust, has low phase noise and large chirp bandwidth, and has no moving parts. Efforts are underway to develop this chirped laser on an integrated chip platform. A need still remains, however, for a FMCW LIDAR detection apparatus and method that can employ low cost low-speed detectors with such a high bandwidth SFL.

Three-dimensional tomographic imaging camera


Methods and systems are provided to develop and use complex automated tasks sequences. The tasks sequences are assembled graphically by assigning Actions to ActionDates. An Action is a component that performs a specific task such as preparing a document or making a database entry. An ActionDate includes the date on which an Action is to be performed. Actions and ActionDates may be grouped using an ActionList. Graphic representations of these ActionList can be added to ActionDates so that groups of tasks and the dates on which they are to be performed can be added to the task sequence for activities that are repeated at different points in the task list. The dates set in the ActionDate are computed and set dynamically from the ActionDate's relationship with other ActionDates in the task sequence. Once the task sequence is graphically assembled, instances of it are used to automatically perform the task sequence. Generally, the automated task sequence is displayed as an automated checklist with which as user can interact.

The computer has become the "engine" of many enterprises by facilitating the use of computer applications to create, produce and track the work product of a business. Computer applications are available for use in a wide variety of business activities. Among the more popular of these computer applications are groups of general office computer programs that are sold together in "office suites" for use by a broad range of business types. These office suites typically include a word-processing program for creating and editing documents, a spreadsheet program for manipulating numerical or other data and a database program for the storage and retrieval of all types of data. Used alone or in combination, the programs in these office suites (and other computer programs marketed individually) have the potential to enable a wide range of business activities. However, the full potential offered by computer programs is often not realized because of the difficulty in adapting the computer programs for the specific needs of the business.
The power of many general office computer programs has grown dramatically over the last number of years, with many functions having been added to each program that blurs the distinction between individual applications. Some of these added functions are duplicative of functions offered in other programs. This often adds to the complexity of using the applications. Further complicating the use of individual functions is that the method accessing similar functions in different programs is often different-even though the same result may be obtained.
The common wisdom asserts, with not totally unfounded cynicism, that the great majority of users of office suite type computer programs (and other computer programs) learn only a small percentage of the available functions of each program, trading the inefficiencies of doing a task with a program by using the functions that they know against the investment in time and effort that would be necessary to learn how to do that same task in a more efficient way. When a task is performed infrequently, this efficiency tradeoff may make little difference, but for tasks that are performed repeatedly the loss of efficiency in doing something as "I know a way to do it" rather than how it most efficiently could be done might be significant over time.
Many computer applications sold in office suites and separately allow the user to customize a generalized program to the specific tasks required by the business. This customization is done using a variety of tools ranging from those that might be relatively accessible to moderately sophisticated user to tools only suitable for very sophisticated users. For instance, a moderately sophisticated user may be comfortable creating templates and recording macros, while a very sophisticated user might use a high level programming language to directly access the functions of the computer application through an application programming interface ("API") exposed by a computer application for that purpose. Generally, the greater the customization desired, the more sophistication of the user that is required and the greater the investment in time and effort that is required to accomplish the customization.
While the office suite and other computer applications provide a wide range of functions for a broad range of uses, the "one size fits all" approach provides a great deal of potential for addressing the specific tasks of many different types of businesses, often the potential is unrealized because of the effort and expertise that is necessary for customizing these "general" computer applications to the "specific" uses of the business. In some cases and often at significant expense, the business will turn to a professional programmer or consultant to customize the programs from an office suite or other "general" application to the specific uses of the business. In other cases, the business may commission a professional programmer or consultant to program a custom computer program directed to the needs business. Between these two alternatives, a custom program directed to a particular business type may be available for purchase by the business from a developer, but these applications are often are much more expensive and sometimes less reliable than the mass marketed general applications provided.
Many business activities require that a sequence of tasks be performed. Often this sequence of tasks must be performed over time, with a task or group of tasks being performed on a given day (or other time unit) and another task or group of tasks performed on a later day (or other time unit). For example, a series of loan documents might be prepared and forwarded to a customer for signature. Ten days later the business would like to send a follow-up letter if the loan documents had not been returned, or to forward the loan documents to the loan underwriter if the loan documents had been returned. As indicated by this example, the next task in the sequence may be conditional on whether the previous task was completed or directional in that the next task is dependant on what happened with the previous task. Because of the complexity and expense of creating custom programs or the customization of general office programs, user's often use the computer for the individual tasks and take on the sequencing and decisions on what tasks to complete themselves.
There are many other real world examples of time sequenced tasks. While the production and tracking of documents may be sequenced in terms of days, tasks on a manufacturing line might be sequenced in terms of seconds/microseconds, etc. For example, in a given unit, a hole is drilled, one second later the conveyor belt moves the unit under a painting spray gun, which is activated once second later. Customizing computer applications for automating a sequence of tasks in a manufacturing process also require a greater level of sophistication than is possessed by many users. While the following discussion will be framed in the context of an office producing documents, it should be understood that any time sequenced task might be substituted in that discussion.
There is a long-felt and unmet need for methods and systems that provide a quick and straightforward way to create or customize computer applications that automate time sequenced tasks in a way that meets the specific needs of a business or other user. These methods and systems should allow a user with average or better computer skills to easily assemble sequences of tasks into complex customized applications. The methods and systems should provide an easily understandable and intuitive interface that can be easily grasped by the user to assemble and automate complex tasks while insulating the user from much of the underlying programming necessary to implement the task.


An image forming apparatus has a transfer attitude correcting section for correcting a transfer attitude of the transfer sheet to receive the toner image and for conveying the corrected transfer sheet to the transfer section with a timing to match with the movement of the toner image. The transfer attitude correcting section includes a roller unit including a base board rotatable around a center of rotation and a registration roller mounted on the base board, a detecting section for detecting a position of the transfer sheet being conveyed by the registration roller; and a control section for control the roller unit based on detection data detected by the detecting section so as to correct a skew of the transfer sheet by rotating the base board and to correct a deviation of a transfer position of the transfer sheet by shifting the registration roller on the base board.

The present invention relates to an image forming apparatus that forms a toner image on a transfer sheet for outputting, as a copying machine, a printer, a facsimile machine and a multifunctional machine including the aforesaid equipment, and in particular, to control for correcting a transfer attitude of a transfer sheet that is conveyed to a position where a toner image is transferred onto the transfer sheet, wherein the transfer attitude is an attitude to receive a toner image.
In the case of recent image forming apparatuses each being connected with a personal computer, those wherein images and information composed of images and character information (which is also called image information) are inputted, then, printed and outputted are more in terms of a number than those wherein pieces of information composed of characters, figures or of symbols (which is also called character information) are inputted, then, subjected to image forming and outputted.
In the case of outputting image information such as color photos, for example, there are many occasions of the structure wherein an image that is cut off square is fitted in a printable area per page of a transfer sheet. Therefore, if a transfer sheet is conveyed and printed under the condition that the transfer sheet is inclined to the conveyance direction for the transfer sheet (hereinafter referred to as "skew"), a blank space provided between an edge portion of the transfer sheet is inclined because a boundary portion of the square image is in a form of a straight line, and "transfer sheet skew" is more emphasized, resulting in a problem that the transfer sheet skew is interpreted as "image skew" depending on a way of looking at.
Therefore, when outputting image information, the transfer sheet skew is more conspicuous than in the case of outputting character information, thus, it has become a demand that even a slight skew of a transfer sheet which has been allowed so far may also be corrected for conducting forming of high grade images.
In particular, in an image forming apparatus of a type to form a color image by transferring toner images each being formed by each of Y (yellow), M (magenta), C (cyan) and K (black) color toners, and by superposing them, for example, if the skew of a transfer sheet as one mentioned above is caused, a phenomenon called "out of color registration" is generated, and images having lower grade are formed, which has been a problem.
Further, if a transfer sheet deviates in a transverse direction from a transfer standard position, there may be a problem that a transfer position of an image is different for each transfer sheet so that an appearance of the document becomes deteriorated.
Therefore, for correcting the transfer sheet skew of the above kind, there is disclosed a technology capable of correcting the transfer sheet skew which is higher in terms of accuracy than the well-known registration apparatus of a type to correct transfer sheet skew by causing a transfer sheet to hit a pair of rollers.
For example, there is disclosed a technology wherein, when an inclination detection means and a position detection means are arranged at the downstream side of the paired conveyance rollers of the registration apparatus, since detections for a skew of a transfer sheet and for a position of a side edge of the transfer sheet are made under the condition that a recording sheet (transfer sheet) is interposed by the paired conveyance rollers and if the paired conveyance rollers are rotated corresponding to the skew angle showing the skew of the transfer sheet calculated based on the results of the detections, the skew of the transfer sheet can be corrected accurately (for example, see Patent Document 1).
Further, a detection means that detects a skew from the transfer sheet conveyance direction under the condition that sheet S (transfer sheet) is interposed is provided, and when the transfer sheet is skewed, a leading edge position after t sec. after the skew is corrected by swing of a skew correction means is calculated and estimated based on detection signals from a detection means of the skew, and the conveyance speed of the paired registration rollers is calculated depending on an amount of deviation of the leading edge of the transfer sheet after t sec. thus obtained.
Then, based on the results of the calculation, the skew of the transfer sheet is corrected by swinging the skew correction means, so that a leading edge of the transfer sheet and the forefront of an image on the photoreceptor drum may be aligned at the transfer section, and the transfer sheet conveyance speed by the paired registration rollers is adjusted to the conveyance speed obtained by the moment when a leading edge of the transfer sheet arrives at the transfer section, and the transfer sheet is conveyed.
There has been disclosed a technology wherein a skew of the transfer sheet can be corrected extremely accurately without stopping the transfer sheet momentarily, by conveying the transfer sheet to the transfer section at the same speed as the circumferential speed of the photoreceptor drum, after a leading edge of the transfer sheet arrives at the transfer section (for example, see Patent Document 2).
Further, there has been published a technique that a position detecting sensor is arranged in a direction perpendicular to a transfer sheet conveying direction so as to detect an inclination of a transfer sheet by detecting a position on a side edge portion of a transfer sheet along the transfer sheet conveying direction (for example, see Patent Document 3).
(Patent Document 1) TOKUKAIHEI No. 10-67448
(Patent Document 2) TOKUKAI No. 2005-53646
(Patent Document 3) TOKUKAI No. 2005-35709
However, in the Patent Document 1, a left end position or a right end position on a leading edge of the transfer sheet that is in the direction perpendicular to the conveyance direction is not always corrected to the regular position, depending on a position of rotation center of the paired conveyance rollers, although a skew in the direction perpendicular to the conveyance direction is corrected by the rotation of the paired conveyance rollers. Therefore, it is necessary to correct a left end position or a right end position on a leading edge of the transfer sheet to the regular position by moving the transfer sheet in parallel with the direction perpendicular to the conveyance direction. Therefore, when correcting the skew by this parallel movement, the transfer sheet is sometimes skewed again, according to circumstances, which has been a problem.
In the Patent Document 2, a skew correction means is swung based on detection signals coming from a detection means, and a position of the leading edge of the transfer sheet after t sec. from the correction of the skew is estimated, for the correction. Therefore, the timing between the estimation and the actual conveyance speed of the transfer sheet, for example, is not adjusted when occasion demands, resulting in a problem that the skew cannot be corrected sufficiently, although there is an advantage to correct without stopping the transfer sheet momentarily.
In other words, there has been a problem that a skew generated after skew correction and a slight skew that failed to be corrected, for example, cannot be corrected in both the Patent Document 1 and the Patent Document 2, because the skew is corrected based on signals detected once.
Further, although Patent Document 3 discloses a correcting device to correct an inclination of a transfer sheet while sandwiching the transfer sheet, it is necessary to release sandwiching by conveying rollers to convey the transfer sheet during the inclination correction. Accordingly, there is a troublesomeness that the sandwiching operation by the correcting device and the sandwiching operation by the conveying rollers are controlled with timing.

Image forming apparatus with transfer attitude correcting section

Konica Minolta Business Technologies, Inc.