There is provided a pigmented aqueous ink set including:

This invention relates to improved black pigmented ink jet inks, and in particular to a black ink jet ink and an ink set showing an improved tonal appearance.
Ink jet printing is a non-impact method that in response to a digital signal produces droplets of ink that are deposited on a substrate such as paper or transparent film. Ink jet printers have found broad application as output for personal computers in the office and the home. There are several classes of ink jet printer, for instance thermal drop-on-demand printers, piezo drop-on-demand printers, and continuous ink jet printers.
Ink jet printers generally use aqueous inks, and such inks commonly employ dyes as colorants. Several suitable water soluble dyes which have been perfected for ink jet use are known, but there are some deficiencies to the use of these dyes. For instance they remain soluble in water on the printed page and are therefore subject to print defects such as feathering and to leaching by water, for example rain water and coffee. Furthermore, many of the dyes in use have poor light fastness and fade even on exposure to fluorescent lighting used in offices. There is particular difficulty in finding a good black dye to fulfill all these requirements and also provide a neutral black appearance. It is especially noticeable when printing monochrome, or so called black and white images, that gray areas of the image can appear somewhat blue, violet, or brown in shade rather than neutral. A blue shaded image is described as cold toned, and a brown shaded image as warm toned. Although under certain circumstances toned images may be desired, a neutral or nearly neutral shade is normally preferred, and it has become common to use a mixture of black dyes such as those disclosed in PCT WO 00/46309 partly in an attempt to provide the neutral appearance.
However the other difficulties remain, and consequently it is becoming increasingly common to use a black pigment such as carbon black in ink jet inks. The term pigment describes a colorant which is substantially insoluble in the aqueous ink medium. It is expected that prints produced using pigmented inks will display improved fastness to washing and weathering and better light stability. In addition carbon black shows a more neutral tone than dye based black inks.
There is interest in using ink jet prints as a replacement for conventional photographic monochrome, or black and white images. Monochrome prints cannot be produced to a high quality on a standard four color ink jet printer. The alternatives for monochrome printing on a standard four color printer are either to print a monochrome image using all four colors, or to print with the black ink only. Printing with colored inks can result in a overall color cast to the image, and in addition the individual colored dots become visible in the light areas of the print. The alternative, printing with the black ink only, produces grainy prints because effectively the dot resolution of a 600 dpi (dots per inch) printer is reduced to 150 dpi, and this is most noticeable in the light areas of the print.
It is known that the use of more than one black ink (commonly four) of different dilutions (i.e. gray inks) can address these problems. For example it is known to use a conventional black ink in the xe2x80x9cblackxe2x80x9d channel of the printer, and somewhat dilute black inks to feed the three color channels, with the most dilute ink being in the xe2x80x9cyellowxe2x80x9d channel. Such inks may be printed without modification of the control software to produce a monochrome image. The use of all four ink cartridges allows full use of the dot resolution of the printer, but the image still suffers defects, for example that individual dots are visible in low density areas. Furthermore the overall image quality does not equal that of conventional photographic prints.
A better solution is to modify the controlling software and use four inks of increasing dilution. Such a system is commercially available under the trade name ILFORD Archiva MonoKrome Ink. By correct choice of the strength of each of the four inks and the design of the software a high quality image may be produced. Furthermore, the visibility of the dots in the light areas of the print can be reduced by printing such areas with light gray inks, thus increasing the number of dots printed for a given density and reducing the visual impact of any given dot, and the black density may be increased by overprinting one ink with another. One limitation of this approach however is that the image tone is dictated by the color of the inks, and in particular that the lightest, or most dilute inks tend to provide brown, or warm toned images even though carbon black is used as pigment. This effect is the factor which limits the degree of dilution of the most dilute ink. On the other hand, it is generally desirable to increase the dilution of this ink to improve the image quality.
The use of a combination of carbon black with a dye in a black aqueous ink jet ink is known according to European Patent Applications 0 724 968 A, 0 913 438 A, and 1 002 839 A. The use of a combination of carbon black with cyan and magenta pigments is known according to U.S. Pat. No. 5,803,958. However these inks are not described for improving the tone of black and white images. We have found a particular combination of pigments which is useful for providing monochrome images from aqueous ink jet inks.
In the present invention, these purposes, as well as others which will be apparent, are achieved generally by providing a pigmented aqueous ink set which comprises a black ink and at least one dilute ink, wherein at least one of the inks comprises carbon black and Pigment Blue 60. The ratio of black pigment to blue pigment may be between 10:1 and 1:2 and depends on the particular grade of the pigments, the ink formulation, the printing medium and the desired final tone.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description of the invention.
According to the invention there is provided a pigmented aqueous ink set comprising:
(a) A concentrated black ink having a pigment concentration of up to 10% by weight; and
(b) at least one dilute ink (preferably a gray ink) having a pigment concentration below that of the concentrated ink; wherein all the inks additionally comprise an aqueous carrier medium and at least one of the set of inks comprises a combination of carbon black and Pigment Blue 60.
Carbon black is listed in the Pigments and Solvent Dyes section of the Colour Index International, published by the Society of Dyers and Colourists in 1997 as C. I. Pigment Black 7. Examples include furnace black, lamp black, acetylene black, and channel black. It is also possible to use a processed pigment such as self dispersing carbon black or graft carbon black having a surface treated with a resin or the like. Preferably the pigment concentration in the black ink is between about 3% and about 5%.
C. I. Pigment Blue 60 is an indanthrone of the following structure.
Optionally and preferably each ink may also comprise at least one dispersant for the pigments. The purpose of the dispersant is to stabilize the particles and prevent flocculation, aggregation, and settling of the ink. Suitable dispersants for pigmented ink jet inks are well known in the art, and include polymeric dispersants as well as some non-polymeric compounds of the surfactant type. Suitable dispersants for this invention include macromolecular polyionic dispersants, for example copolymers of styrene with acrylic, methacrylic, or maleic acids; various types of poly(ethylene oxide) condensates such as alkyl polyethylene oxide ethers and sulfate or phosphate esters thereof; and surfactants such as sarcosinate compounds. The ink may contain up to 400% of the dispersant by weight on the pigment, but preferably between about 10% and about 100% by weight on the pigment, and most preferably approximately 20 to 50% by weight on the pigment, depending on the pigment used and other properties desired of the ink.
A preferred dispersant for the inks of this invention is a copolymer of styrene with acrylic or methacrylic acids, together with optionally additional vinylically unsaturated comonomers such as acrylate esters. Preferably this dispersant is characterized by an acid number of between about 150 and about 250, a glass transition temperature between about 70xc2x0 and about 100xc2x0, and a molecular weight of between about 2000 and about 20000, and most preferably the acid number is between 150 and 200 and the molecular weight is approximately 5000-15000. Many suitable styrene acrylate dispersants are commercially available. Such styrene acrylate copolymer dispersants may be supplied commercially in the form of concentrated solutions in aqueous base, or as solids which are to be dissolved in water in the presence of a base. Suitable bases for dissolving such dispersants include sodium or potassium hydroxide, ammonia, or an organic amine base such as ethanolamine, triethanolamine, 2-amino-2-methyl-1-propanol, or 1-(dimethylamino)-2-propanol. It is also possible to use mixtures of such bases to dissolve the styrene acrylate copolymer.
The pigment may be used in the form of a dry powder. However pigments are often supplied commercially as a concentrated aqueous pigment dispersion, and this invention is also useful for pigments supplied as such dispersions, which commonly include dispersants and other cosolvents as well as water. Alternatively the pigment may be supplied in the form of a water wet presscake. In presscake form, the pigment is not aggregated to the extent that it is in dry form and thus the pigment does not require as much deaggregation in the process of preparing the inks from dry pigments.
The ink may contain up to approximately 10% of each pigment by weight. The ratio of the black pigment to the blue pigment may be between 10:1 and 1:2, preferably between approximately 2:1 and approximately 1:1, by weight. The ratio depends on the particular grade of the black and blue pigment, the ink formulation, the printing medium, and the desired final tone. The ratio may vary with the concentration of the pigments in the ink. In addition to providing neutral toned prints, controlled warm or cold toned prints may be produced by appropriately changing the pigment ratio.
By an aqueous carrier medium is meant a medium which is water or is predominantly water. It is common in aqueous ink jet inks to employ a carrier medium which is a mixture of water and at least one relatively involatile water soluble organic cosolvent. The purpose of the cosolvent is to act as humectant and prevent drying out of the ink in the nozzles of the printer, to improve printing performance, and also to improve the appearance of the final image. Deionised water is commonly used.
Preferably each ink comprises a mixture of water and at least one water soluble organic cosolvent. The water soluble organic cosolvent may be any organic solvent which has sufficient solubility in water. Representative examples of water-soluble organic solvents that may be selected include:
(1) alcohols, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, t-butyl alcohol, iso-butyl alcohol, neopentyl alcohol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol;
(2) ketones or ketoalcohols such as acetone, methyl ethyl ketone and diacetone alcohol;
(3) ethers, such as tetrahydrofuran and dioxane;
(4) esters, such as ethyl lactate;
(5) polyhydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, diacetone alcohol, trimethylolpropane, 2-methyl-2,4-pentanediol, 2,3,4-trimethyl-1,3-pentanediol, 1,3-propanediol, 1,5-pentanediol, glycerol, 1,2-hexanediol, and 1,2,6-hexanetriol;
(6) lower alkyl mono- or di-ethers derived from alkylene glycols, such as ethylene glycol monomethyl (or -ethyl) ether, diethylene glycol mono-methyl (or -ethyl) ether, propylene glycol mono-methyl (or -ethyl) ether, triethylene glycol mono-methyl (or -ethyl) ether and diethylene glycol di-methyl (or -ethyl) ether;
(7) sulfur-containing compounds such as tetramethylene sulfone, dimethyl sulfoxide, and thiodiglycol; and
(8) nitrogen containing organic compounds such as 1,3-dimethyl imidazolidinone, urea, pyrrolidone and N-methyl-2-pyrrolidone.
Selection of a suitable mixture of water and water soluble organic cosolvent depends on the requirements of the specific application, such as the desired surface tension and viscosity, the selected pigment, the drying time of the pigmented ink jet ink, and the type of substrate onto which the ink will be printed. A mixture of water and at least one water soluble organic solvent having at least 2 hydroxyl groups is preferred. Therefore preferred organic cosolvents include for example diethylene glycol, triethylene glycol, polyethylene glycol, thiodiglycol, glycerol, 1,2-hexanediol, 1,5-pentanediol, and mixtures comprising these solvents. The aqueous ink composition may contain up to 50% of the organic cosolvent or mixture of organic cosolvents. Preferably the ink comprises up to 10% of each organic cosolvent, and most preferably between about 5% and about 10% of each of a mixture of at least two organic cosolvents.
The pigmented inks of the invention may also comprise other components which are advantageously added to aqueous ink jet inks, such as surfactants, viscosity modifiers, and biocides. In addition, sequestering agents such as EDTA may also be included to eliminate deleterious effects of heavy metal impurities.
It is generally desirable to prepare a concentrated dispersion by dispersing the pigment in water in the presence of one or more dispersants, and then to dilute this dispersion with additional water together with the organic solvent or solvents together with any other additives to form the ink. This technique permits preparation of a greater quantity of pigmented ink from the equipment. By dilution, the ink is adjusted to provide the desired concentration, color strength, and other properties for the particular application. The surface tension is preferably in the range from about 30 dyne/cm to about 50 dyne/cm and the viscosity is generally no greater than 20 cP, and preferably in the range from about 1 cP to about 10 cP. Alternatively the cosolvent and any other additives may be present during the dispersion stage. The inks of the invention may either be prepared by dispersing the pigments separately to produce two separate dispersions and then combining them at dilution, or by dispersing a combination of the pigments.
The dispersing step may be accomplished by many well known methods, for example in a horizontal mini mill, a ball mill, a roll mill, an attritor, a homogeniser or by passing the mixture through a plurality of nozzles within a liquid jet interaction chamber at a liquid pressure of at least 1000 psi to produce a uniform dispersion of the pigment particles in the aqueous carrier medium.
The particle size of the pigment is preferably 10 xcexcm or less, particularly preferably 1 xcexcm or less and most preferably from 0.005 to 0.3 xcexcm.
According to one particularly preferred embodiment of the invention there is provided a pigmented aqueous ink set of four inks comprising:
(a) A concentrated ink having a pigment concentration between about 3% and 5% by weight;
(b) a dilute ink having a pigment concentration between about 1% and about 4% by weight;
(c) a more dilute ink having a pigment concentration between about 0.5% and about 3% by weight; and
(d) a most dilute ink having a pigment concentration between about 0.1% and about 1% by weight;
wherein all the inks additionally comprise an aqueous carrier medium as herein before defined and at least one of the inks comprises a combination of carbon black and Pigment Blue 60.
It is to be understood that the preferred pigment concentration of each of the inks depends on the controlling software as well as the printer to be used, the type of substrate onto which the ink will be printed, and the desired visual result. However in general the preferred pigment concentration of the black ink (a) is approximately 3.5%, that of the second ink (b) is between 1% and 3%, that of the third ink (c) between 0.5% and 2%, and that of the most dilute ink (d) between 0.1% and 0.8%. Most preferably the three dilute inks all comprise the combination of carbon black and Pigment Blue 60. The weight ratio between the carbon black and Pigment Blue 60 may be different in the different inks of the ink set. For certain uses it is preferable that the proportion of blue pigment will be greater in the ink or inks of lowest concentration.
The inks of the pigmented ink set of this aspect of the invention may advantageously also comprise other components as herein before defined such as a dispersant. An additional colorant may also be present, but one of the advantages of the ink set of the invention is that a good image tone is provided using simple combinations of just two pigments.
The ink set of this aspect of the invention produces pleasing high quality images of good image tone and high maximum density but showing minimum dot visibility in the highlight areas of the print. A further advantage of the inks of the present invention is that the prints exhibit excellent lightfastness.
In another embodiment of the present invention, there is provided a process of printing using the ink and ink set of the invention. The printing is effected by using the ink set in an ink jet printer, and applying the ink to a printing medium which can be any of the substrates commonly used for ink-jet printing, for example so-called plain paper, coated paper, wet strength paper, fine art paper, canvas, self-adhesive vinyl, scrim vinyl, overhead transparencies, fabrics, and synthetic media such as white polyester and bonded nonwoven polyolefin film-fibril sheets such as polyethylene or polypropylene banner materials.
The inks and ink set of this invention may be used with a variety of ink jet printers such as continuous, piezoelectric drop-on-demand and thermal or bubble jet drop-on-demand, and are particularly adapted for use in piezoelectric and thermal drop on demand printers. The printer may be a desk top printer or a wide format ink jet printer.
The stability of the ink formulation also allows long storage periods without any loss of printability.
The following examples will serve to illustrate the invention. These examples are merely representative and are not inclusive of all the possible embodiments of the invention.

Pigmented aqueous inks and ink set for ink jet printing

Abstract: (a) A concentrated black ink having a pigment concentration up to 10% by weight; and

Abstract: (b) at least one dilute ink having a pigment concentration below that of the concentrated ink;

Abstract: wherein all the inks additionally includes an aqueous carrier medium and at least one of the set of inks includes a combination of carbon black and Pigment Blue 60.


One embodiment of the present invention relates to a method for performing discovery by a device supporting Wi-Fi Direct, the method comprising the steps of: calling, by a service end, a SeekService method and an AdvertiseService method; and transmitting a probe request on the basis of at least one of the SeekService method and the AdvertiseService method, wherein when the type field of the SeekService method is active and the periodic field of the AdvertiseService method is 1 or higher, the probe request includes a service hash generated from the service_name of the SeekService method, and a service hash and an advertisement ID generated from the service_name of the AdvertiseService method.

Along with the recent development of information and communication technology, various wireless communication technologies have been developed. Among them, Wireless Local Area Network (WLAN) enables wireless access to the Internet based on radio frequency technology through a portable terminal such as a Personal Digital Assistant (PDA), a laptop computer, a Portable Multimedia Player (PMP) in a home, an office, or a specific service providing area.
The introduction of Wi-Fi Direct or Wi-Fi Peer-to-Peer (Wi-Fi P2P) is under discussion, as a direct communication technology that facilitates interconnection between devices without a wireless Access Point (AP) which is a basic requirement for a legacy WLAN system. According to Wi-Fi Direct, devices can be connected to each other without a complex establishment procedure and an operation for exchanging data at a communication rate offered by a general WLAN system can be supported to provide various services to users.
Recently, various Wi-Fi-enabled devices have been used. Among them, the number of Wi-Fi Direct-enabled devices which are Wi-Fi devices capable of communicating with each other without an AP is increasing. The Wi-Fi Alliance (WFA) has been discussing the introduction of a platform supporting various services (e.g., Send, Play, Display, Print, etc.) using a Wi-Fi Direct link. This may be referred to as Wi-Fi Direct Service (WFDS). According to WFDS, applications, services, etc. can be controlled or managed by a service platform called Application Service Platform (ASP).
A standard on a wireless LAN (WLAN) technology is developing in IEEE (Institute of Electrical and Electronic Engineers) 802.11 group. IEEE 802.11a and b use an unlicensed band in 2.4 GHz or 5 GHz and IEEE 802.11b provides transmission speed of 11 Mbps, and IEEE 802.11a provides transmission speed of 54 Mbps. IEEE 802.11g provides transmission speed of 54 Mbps by applying OFDM (Orthogonal Frequency Division Multiplexing) in 2.4 GHz. IEEE 802.11n provides transmission speed of 300 Mbps by applying MIMO-OFDM (Multiple Input Multiple Output-OFDM). IEEE 802.11n supports a channel bandwidth up to 40 MHz. In this case, IEEE 802.11n can provide transmission speed of 600 Mbps.
In WLAN environment according to IEEE 802.11e, a DLS (Direct Link Setup)-related protocol assumes that a BSS (Basic Service Set) corresponds to a QBSS (Quality BSS) supporting a QoS (Quality of Service). In the QBSS, not only a non-AP STA but also an AP corresponds to a QAP (Quality AP) that supports QoS. Yet, in a currently commercialized WLAN environment (e.g., WLAN environment according to IEEE 802.11a/b/g), although a non-AP STA corresponds to a QSTA (Quality STA) supporting QoS, most of APs correspond to a legacy AP incapable of supporting QoS. As a result, even a QSTA has a limit on using a DLS service in the currently commercialized WLAN environment.
A TDLS (Tunneled Direct Link Setup) corresponds to a wireless communication protocol newly proposed to overcome the aforementioned limit. Although the TDLS does not support QoS, the TDLS can make QSTAs establish a direct link in the currently commercialized WLAN environment such as IEE 802.11a/b/g and enable a direct link to be established in a PSM (power save mode). Hence, the TDLS regulates various procedures to make QSTAs establish a direct link in a BSS managed by a legacy AP as well. In the following, a wireless network supporting the TDLS is referred to as a TDLS wireless network.
A legacy wireless LAN mainly handles an operation of an infra structure BSS in which a wireless access point (AP) functions as a hub. An AP is in charge of a function of supporting a physical layer for establishing a wired/wireless connection, a function of routing devices in a network, a function of providing a service for adding/deleting a device to/from a network, and the like. In this case, the devices in the network are connected with each other via the AP and the devices are not directly connected with each other.
As a technology of supporting a direct connection between devices, discussion on establishing a standard for Wi-Fi Direct is in progress.
A Wi-Fi direct network corresponds to a network that Wi-Fi devices are able to perform D2D (Device to Device) (or P2P (Peer-to-Peer)) communication with each other although the Wi-Fi devices do not participate in a home network, an office network, and a hotspot network. The Wi-Fi direct network has been proposed by Wi-Fi Alliance. In the following, Wi-Fi Direct-based communication is referred to as Wi-Fi D2D communication (simply, D2D communication) or Wi-Fi P2P communication (simply, P2P communication). And, a device for performing the Wi-Fi P2P is referred to as a Wi-Fi P2P device, simply, a P2P device.
A WFDS network can include one or more Wi-Fi devices. A WFDS device includes devices supporting Wi-Fi such as a display device, a printer, a digital camera, a projector, a smartphone, and the like. And, the WFDS device includes a non-AP STA and an AP STA. WFDS devices belonging to a WFDS network can be directly connected with each other. Specifically, P2P communication may indicate a case that a signal transmission path between two WFDS devices is directly configured between the WFDS devices without passing through the third device (e.g., an AP) or a legacy network (e.g., accessing WLAN via an AP). In this case, the signal transmission path directly configured between the two WFDS devices can be restricted to a data transmission path. For example, the P2P communication may indicate a case that a plurality of non-STAs transmit data (e.g., voice/image/text message information, etc.) without passing through an AP. A signal transmission path for control information (e.g., resource allocation information for P2P configuration, wireless device identification information, etc.) can be directly configured between WFDS devices (e.g., between a non-AP STA and a non-AP STA, between a non-AP STA and an AP), can be configured between two devices (e.g., between a non-AP STA and a non-AP STA) via an AP, or can be configured between an AP and a corresponding WFDS device (e.g., between an AP and a non-AP STA #1, between an AP and a non-AP STA #2).
Wi-Fi Direct corresponds to a network connection standard technology for defining up to an operation of a link layer. Since a standard on an application, which is operating in a higher layer of a link configured by the Wi-Fi Direct, is not defined, when an application is executed after devices supporting the Wi-Fi Direct are connected with each other, it was difficult to support compatibility. In order to solve the aforementioned problem, discussion on standardizing such a higher layer application as a Wi-Fi direct service (WFDS) is in progress in Wi-Fi Alliance (WFA).
FIG. 1 illustrates components of a WFDS (Wi-Fi Direct Service) framework.
Referring to FIG. 1, a Wi-Fi Direct layer is a MAC layer defined by the Wi-Fi Direct standard. The Wi-Fi Direct layer may include software compatible with the Wi-Fi Direct standard. A wireless connection may be configured by a PHY layer (not shown) compatible with the Wi-Fi PHY layer, under the Wi-Fi Direct layer. A platform called Application Service Platform (APS) is defined above the Wi-Fi Direct layer.
The ASP is a common shared platform and performs session management, service command processing, and control and security between ASPs between its overlying Application layer and its underlying Wi-Fi Direct layer.
A Service layer is defined above the ASP. The Service layer includes use case-specific services. The WFA defines four basic services, Send, Play, Display, and Print. Also, an Enable Application Program Interface (API) is defined to use an ASP common platform when a third party application other than the basic services is supported.
While Send, Play, Display, Print, or services defined by third party applications are shown in FIG. 1 as exemplary services, the scope of the present invention is not limited thereto. For example, the term "service" may mean any of services supporting Wi-Fi Serial Bus (WSB), Wi-Fi Docking, or Neighbor Awareness Networking (NAN), in addition to Send, Play, Display, Print, or the services defined by the third party applications.
Send is a service and application that can perform file transfer between two WFDS devices. Play is a service and application that enable sharing or streaming of Digital Living Network Alliance (DLNS)-based Audio/Video (A/V), photos, music, etc. between two WFDS devices. Print is a service and application that enable output of text and photos between a device having content such as text, photos, etc. and a printer. Display is a service and application that enable screen sharing between a Miracast source and a Miracast sink of the WFA.
The Application layer may provide a User Interface (UI), represent information as a human-perceivable form, and provide a user input to a lower layer.

Method and apparatus for performing discovery by device supporting Wi-Fi Direct in wireless communication system


A process for coating three-dimensional, electrically conductive substrates by applying a coating layer of a stoving coating composition substantially only to the exterior surfaces of the substrates at a layer thickness sufficient to electrically insulate such surfaces, stoving the coating layer and then coating the interior surfaces with an electrodeposition coating composition, wherein the stoving coating composition is characterised by a volume resistivity from 108 to 1011 Ohmxc2x7cm of applied and stoved coating layers of said composition.

The invention relates to a process for coating three-dimensional, electrically conductive substrates, and to the substrates coated accordingly.
Present-day automotive coatings are prepared predominantly by applying an electrodeposition coating primer, a primer surfacer layer and a one-coat top coating or a two-coat top coating comprising a base coat and a clear coat layer.
In the past, a coating process which became known as the xe2x80x9creverse processxe2x80x9d was used, wherein initially a primer surfacer layer was applied directly to the metallic outer skin of a motor vehicle body and stoved. Then, an electrodeposition coating primer was applied to the metal surfaces inside the body which had remained uncoated, and stoved. See G. Fetdis, Automotive paints and coatings, Verlag Chemie, Weinheim, 1995, pages 61-63. The motor vehicle bodies coated by the xe2x80x9creverse processxe2x80x9d were characterised by an outstanding optical surface quality but had insufficient corrosion protection in the transition area between parts of the body surface coated with primer surfacer and with electrodeposition coating primer.
A process is known from EP-A-0 982 413 which is intended to overcome the disadvantages of the xe2x80x9creverse processxe2x80x9d in that a plastics film is bonded to the exterior visible surfaces of a motor vehicle body and electrodeposition coating priming of the metallic surface not provided with plastics film subsequently takes place. The application of the plastics film to achieve an exact fit is complicated, labour-intensive and represents a source of trouble.
The object of the present invention is to avoid the above-mentioned weaknesses in corrosion protection of three-dimensional objects, particularly motor vehicle bodies, coated by the xe2x80x9creverse processxe2x80x9d principle.
The invention provides a process for coating three-dimensional, electrically conductive substrates having interior and exterior surfaces; the process comprising (a) applying a coating layer of a stoving coating composition substantially only to the exterior surfaces of the substrate; (b) stoving the coating layer; and (c) applying an electrodeposition coating composition substantially only to the interior surfaces of the substrate, wherein the stoving coating composition is applied at a coating thickness sufficient to electrically insulate the exterior surfaces of the substrate and wherein the stoving coating composition is characterised by a volume resistivity from 108 to 1011 Ohmxc2x7cm of applied and stoved coating layers of said composition.
The references to thickness of a coating composition, such as by the phrases xe2x80x9clayer thicknessxe2x80x9d, xe2x80x9ccoating thicknessxe2x80x9d and the like means the dry film thickness of the layer or coating concerned.
In the process according to the invention, three-dimensional, electrically conductive substrates, particularly metal substrates such as motor vehicle bodies and motor vehicle body parts are coated. Examples of metals used in such substrates include galvanised or ungalvanised steel, aluminium and/or magnesium. The metals can be pretreated, for example phosphated and passivated and/or electrically conductive precoated. Composite substrates of such metals and, for example, plastics, are also suitable.
Initially, in the process according to the invention, a coating layer of a stoving coating composition is applied substantially only to the exterior surfaces of the three-dimensional substrates and stoved. The composition is applied at a sufficient thickness to ensure insufficient electrical conductivity for the deposition of an electrodeposition coating layer on the stoved coating layer. In other words, the stoving coating composition is applied at a thickness sufficient to electrically insulate the exterior surfaces of the substrate. The exterior surfaces include, for example, surfaces of a motor vehicle body which are directly visible to the observer from the outside of the vehicle, i.e., body panels, doors, hood, trunk lid, etc.
The stoving coating compositions may be waterborne stoving coating compositions to be applied by electrodeposition, for example, electro powder coatings. Preferably, however, they are waterborne, solvent-based or powder stoving coating compositions to be applied by spraying.
The stoving coating compositions contain conventional cross-linkable binders. These binders may be self cross-linking or may be cross-linked by the use of a separate cross-linking agent. Cross-linkable binder systems known to the skilled person and used in primer surfacer coating compositions are particularly suitable. Examples of binders are polyester, epoxy and polyurethane resins. Examples of cross-linking agents are aminoplastic resins such as melamine resins, benzoguanamine resins and blocked polyisocyanates. The solids weight ratio (parts by weight) between binders and cross-linking agents is preferably 60:40 to 90:10.
It is important for the invention to select the stoving coating compositions such that applied and stoved coating layers of said compositions have a volume resistivity from 108 to 1011, preferably 1010 to 8xc3x971010 Ohmxc2x7cm. The volume resistivity may be measured by conventional methods known to the skilled person, as described for example in DIN IEC 93. In order to obtain the volume resistivity of 108 to 1011 Ohmxc2x7cm, the stoving coating compositions preferably contain electrical conductive components. Examples of such components are particulate inorganic or organic electrical conductors or semi-conductors, such as, for example, black iron oxide, graphite, conductive carbon black, metal powder, e.g. of aluminium, zinc, copper or refined steel, molybdenum disulfide, in particular conductive pigments such as, for example, doped pearlescent pigments, for example, mica platelets provided with a thin layer of antimony-doped tin oxide, or conductive barium sulfate in which the particle core is coated with a thin layer of antimony-doped tin oxide. Electrically conductive polymers such as, e.g., polyaniline, are also suitable but less preferred. The electrically conductive components may be used alone or in combination. They may be introduced into the stoving coating compositions in the same way as conventional coating pigments or fillers. The amount of electrically conductive components needed in the stoving coating composition is, for example, from 1 to 30 wt. %, based on the solids content. The amount needed for any particular composition may be determined easily by the skilled person and is dependent upon, for example, the specific gravity, the specific electrical conductivity and the particle size of the electrically conductive components.
In addition to binders, cross-linking agents and the electrically conductive components and optionally water and/or organic solvents (for liquid compositions), the stoving coating compositions generally contain pigments and/or fillers. The amount of pigment and/or filler used is typically an amount sufficient to provide a pigment/filler to binder solids weight ratio of 0.1:1 to 2:1. When calculating the pigment/filler to binder solids weight ratio, the electrically conductive components are counted as pigment/filler and the weight of binders solids includes any cross-linking agents.
Examples of pigments and/or fillers used in addition to the electrically conductive components include conventional inorganic and/or organic colored pigments and/or fillers such as carbon black, titanium dioxide, iron oxide pigments, phthalocyanine pigments, quinacridone pigments, azo pigments, barium sulfate, calcium carbonate, kaolin, talc or silica.
Pigments, fillers as well as electrically conductive components may be introduced separately or in mixture into the stoving coating compositions. The nature of introduction is immaterial; the methods known to the skilled person for the preparation of coatings may be used, for example, the addition during the course of a preparation from scratch by way of appropriate pastes or by subsequent addition to an inherently finished stoving coating composition, for example, one ready for application. The particles are dispersed in each case or even ground.
The stoving coating compositions are applied in a layer thickness sufficient to electrically insulate the exterior surfaces of the substrate. This ensures that, in the subsequent process steps, the stoving coating composition is not overcoated with the electrodeposition layer. The layer thickness corresponds at least to the minimum layer thickness of, for example, 3 to 10 xcexcm, providing sufficient electrical insulation, and the desired layer thickness of the stoving coating layer is preferably greater than the minimum layer thickness. For example, the desired layer thickness is 15 to 100 xcexcm, preferably 25 to 80 xcexcm. The stoving coating composition is preferably applied by spraying. After application of the stoving coating composition, the coating is stoved at temperatures from, for example 80 to 180xc2x0 C.
In the process of the invention, the stoving coating composition is applied substantially only to the exterior surfaces of the three-dimensional substrates. It should be understood, however, that in practice other surfaces of the substrates also get coated to some extent in the application of the stoving coating composition such as, for example, from overspray. The coating of these other surfaces is, however, at a thickness substantially less than that required to electrically insulate the surface. A transition zone is therefore formed between surface parts of the three-dimensional substrates provided with the stoving coating layer and those to be provided with the electrodeposition coating composition.
In the transition zone, the thickness of the stoving coating layer decreases from the minimum layer thickness to 0 over the width of the transition zone. A coating with electrodeposition coating agent is possible below the minimum layer thickness of the stoving coating layer. An increasing layer thickness of an electrodeposition coating layer deposited on the stoving coating layer can be obtained starting from this minimum layer thickness down to smaller layer thicknesses of the stoving coating layer in the transition zone. In the above mentioned transition zone it is therefore possible to deposit an electrodeposition coating, the layer thickness of which depends on the layer thickness below the minimum thickness of the stoving coating layer.
The width of this transition zone typically varies between 0.2 and 20 cm and depends on various factors such as the structural features of the substrate and on the application conditions for the stoving coating composition. Examples of structural features include various types of openings in the exterior surface (such as for windows, sliding roof, or assembly openings in a motor vehicle body). Examples of application conditions include the handling of spray-coating devices, air flow conditions, spray application with or without electrostatic support.
After application and stoving of the stoving coating layer, the interior surfaces, including the transition zone, are coated in an electrodeposition coating bath in the conventional way known to the skilled person. Suitable electrodeposition coatings include conventional waterborne coating compositions with a solids content from, for example, 10 to 30 wt. %.
The electrodeposition coating compositions may be conventional anodic electrodeposition coating agents known to the skilled person. The binder basis of the anodic electrodeposition coating composition may be chosen at will. Examples of anodic electrodeposition binders are polyesters, epoxy resin esters, (meth)acrylic copolymer resins, maleinate oils or polybutadiene oils with a weight average molecular mass (Mw) of, for example, 300-10 000 and a carboxyl group content, for example, corresponding to an acid value of 35 to 300 mg KOH/g. At least a part of the carboxyl groups is converted to carboxylate groups by neutralisation with bases. These binders may be self cross-linking or cross-linked with separate cross-linking agents.
Preferably conventional cathodic electrodeposition coating agents known to the skilled person are used in the process according to the invention for the application of the electrodeposition coating layer. Cathodic electrodeposition coating compositions contain binders with cationic groups or groups which can be converted to cationic groups, for example, basic groups. Examples include amino, ammonium, e.g., quaternary ammonium, phosphonium and/or sulfonium groups. Nitrogen-containing basic groups are preferred; said groups may be present in the quaternised form or they are converted to cationic groups with a conventional neutralising agent, e.g., an organic monocarboxylic acid such as, e.g., formic acid, lactic acid, methane sulfonic acid or acetic acid. Examples of basic resins are those with primary, secondary and/or tertiary amino groups corresponding to an amine value from, for example 20 to 200 mg KOH/g. The weight average molecular mass (Mw) of the binders is preferably 300 to 10 000. Examples of such binders are amino(meth)acrylic resins, aminoepoxy resins, aminoepoxy resins with terminal double bonds, aminoepoxy resins with primary OH groups, aminopolyurethane resins, amino group-containing polybutadiene resins or modified epoxy resin-carbon dioxide-amine reaction products. These binders may be self-cross-linking or they may be used with known cross-linking agents in the mixture. Examples of such cross-linking agents include aminoplastic resins, blocked polyisocyanates, cross-linking agents with terminal double bonds, polyepoxy compounds or cross-linking agents containing groups capable of transesterification.
Apart from binders and any separate cross-linking agents, the electrodeposition coating compositions may contain pigments, fillers and/or conventional coating additives. Examples of suitable pigments include conventional inorganic and/or organic colored pigments and/or fillers, such as carbon black, titanium dioxide, iron oxide pigments, phthalocyanine pigments, quinacridone pigments, kaolin, talc or silicon dioxide. Examples of additives include, in particular, wetting agents, neutralising agents, levelling agents, catalysts, corrosion inhibitors, anti-cratering agents, anti-foaming agents, solvents.
Electrodeposition coating compositions which have good throwing power behaviour are preferred in the process according to the invention.
Electrodeposition coating takes place in a conventional manner known to the skilled person, for example, at deposition voltages from 200 to 500 V, preferably under application conditions which permit good throwing power, if possible. After deposition of the electrodeposition coating, the substrate is again stoved at object temperatures from, for example, 120 to 180xc2x0 C.
It is not usually possible to deposit an electrodeposition coating layer onto interior surfaces of a three-dimensional substrate in a layer thickness which is the same everywhere. The application of the electrodeposition coating layer takes place in the process according to the invention in a layer thickness which ensures adequate corrosion protection on the interior surfaces of the three-dimensional substrates. For example, the electrodeposition coating layer thickness should be in a range from 3 to 40, preferably 5 to 15 xcexcm.
The three-dimensional substrates coated according to the procedure of the invention have on their exterior surfaces a coating layer of a stoving coating composition whereas the interior surfaces are provided with an electrodeposition coating. Although the substrates in the process according to the invention are coated according to the xe2x80x9creverse processxe2x80x9d principle, they exhibit good resistance to corrosion covering the entire surface which is not achieved in three-dimensional substrates coated according to the reverse process of the prior art.
The substrates coated with stoving coating layer and electrodeposition coating primer may be provided with one or more further coating layers, particularly on the exterior surfaces. Initially, an intermediate layer may be applied and optionally stoved before a top coating is applied. For motor vehicle applications, the intermediate layer is preferably not used. The top coating may be applied from a waterborne, solvent-based or powder top coat as a single-layer top coating which determines the color shade, or it is applied as a two-layer top coating in the conventional manner, preferably wet-in-wet from a waterborne, solvent-based or powder base coat which determines the color shade and/or special effect, and a waterborne, solvent-based or powder clear coat.
The process according to the invention is particularly suitable for motor vehicle coating. Motor vehicle bodies prepared therewith have not only good corrosion protection but also an outstanding optical surface quality (appearance, gloss) as a consequence of the primer of the stoving coating composition applied to their exterior surfaces. The stoving coating composition produces inherently smoother coatings versus conventional electrodeposition coating primer layers and thus offers a favourable basis for a smooth surface of the subsequent coating layers.

Process for coating three-dimensional electrically conductive substrates


A double-edged utility knife for carpet installers, roofers, glaziers and sheet rock workers has a two-part handle. The handle clamps a detachable reversible double-edged blade at a transverse angulated position with respect thereto. Vertical cuts can be made in tight corners without applying excessive force. The transversely angulated knife blade affords access permitting vertical cuts in tight corners. During cutting the user's hands are displaced from the cutting line, and kept from being inline with the cutting blades. Operation-induced injuries are virtually eliminated. The double edge blade is provided with a geometry especially well suited for wallboard, roofing, carpet cutting/glue scraping and glazier use.

1. Field of the Invention
This invention relates to utility knives for operations such as glazing, roofing carpeting and sheet rock fabrication wherein the knife is used in close proximity to window edges or close-by walls; and more particularly to a knife that facilitates cutting in a direction perpendicular to the surface appointed to be cut while, at the same time, minimizing injury to the user.
2. Description of the Prior Art
Tools have long been used for line cutting in glazing and sheet rock installation. U.S. Pat. No. 2,242,900 to Bender discloses an adjustable tool holder and cutting device appointed for cutting paper, fabric, leather, felt, packing, cardboard, flowers, and the like. Holders of this type have conventionally been used by glaziers. The holder comprises a handle having a longitudinal guide slot to accommodate a cutting tool. A screw passes through the guide slot and engages a locking nut to secure the cutting tool in various extensions and positions. The tool holder is constrained to lie in the plane of a longitudinal guide slot parallel to the wide side of the handle, and is therefore in-line with the handle. No alignment pin or other structure is used to positively and rigidly mount the blade and prevent extension of the tool to a significant extent.
U.S. Pat. No. 2,304,332 to Bodkin discloses a scraping and cutting device comprising a holder adapted to retain a single-edged razor blade. The blade has a recess or aperture therein and a reinforcing member tightly clamped around one of the razor blade's edges. The holder comprises a pair of handle members, each of which is pivotally secured adjacent one end. A spacing member holds the handle members apart sufficiently to permit insertion and movement of the razor blade between the handle members. The opposite ends of the handle members have their ends formed obliquely to the axes of the members. A longitudinally extending channel in each of the handle members is provided for receiving the reinforcing member of the razor blade so as to either hold it within the handle or to project it in a cutting position beyond the oblique ends of the handle. A bolt and screw clamping means passes through slots in the handle members and through a recess of the blade. The clamping means may be loosened to permit movement of the blade within the holder or tightened to securely engage the blade in cutting or scraping position. Each handle member is further provided with a transverse channel extending across the width of, and substantially parallel to the oblique end of, the handle member. The reinforcing member of the razor blade may be placed in the transverse channel and the clamping means tightened to hold the blade in the scraping position. With this arrangement, the blade is in line with the handle and the blade extension is small and is controlled by position of the blade in the channel. In addition, there is lacking any alignment pin or similar means for positively locating the extension of the blade. Consequently, the device must rely solely on friction that results from the tightening of a bolt and screw tightening means.
U.S. Pat. No. 2,679,100 to Ehler discloses a knife for cutting linoleum and the like. The knife comprises a handle holding a removable blade. The handle comprises two halves, each having a blade-receiving end with a channel of the width of the blades the handle is to receive. The halves are assembled by using a screw. Pins are provided in one half for insertion in corresponding sockets in the opposite half to assure proper association of the halves upon assembly. A blade-locating lug extending from the wall of the channel engages a slot in the blade. In one embodiment the blade projects generally along the long axis of the mating halves of the handle. In another embodiment, the blade extends from the bottom edge of the handle at an angle obtuse a predetermined degree suitable for linoleum cutting in the handle plane. Significantly, there is no disclosure concerning a knife having transverse angulation of its cutting blade, maintaining the angularity of the knife blade with respect to the handle. Instead, the blade is constrained to be located in a recess in one of the sides of its handle. With this configuration, the blade of the knife is substantially co-planar with the inside surfaces of the sides of the assembled handle and has no ability to produce perpendicular cuts to a surface in close location, such as that required in glazing and sheet rock operations.
U.S. Pat. No. 2,784,489 to Reise discloses a hand holder for utility blades used by craftsmen and others for cutting roofing materials, linoleum, and the like. The blade holder is said to have a forwardly movable guard for protecting the blade when not in use and provision for ready adjustment of the blade projection, convenient replacement of the blade, and storage space for extra blades. The holder has an open, forward end containing a rectangular cavity adapted to receive the guard in sliding association. The guard has a blunt nose-shaped forward end, side grooves, a rectangular recess adapted to receive the blade and a flat cover piece, and an elongated opening through the upper portion of the guard. A finger knob protrusion is provided in the rear bottom portion of the guard to allow a user to slide the guard backward and forward. Sliding the guard backward into the cavity of the holder exposes the blade, while sliding the guard forward shields the blade. A bolt penetrates one side of the holder. The bolt passes through the blade guard, an alignment notch atop the blade, and the cover piece; and thence through the opposite side of the holder, where it is engaged by a nut. Tightening the nut secures the blade and guard in position. The blade is in-line with the handle and not transversely angled and rigidly mounted.
U.S. Pat. No. 2,788,574 to Marcmann discloses a utility knife having a handle and blade which may be fixed in a number of different positions therein to suit different cutting purposes. The blade may be set to project in a straight line from one end of the handle to provide blades of different lengths and with different amounts of cutting edge and different degrees of rigidity or stiffness. The blade may also be set at an angle to the length of the handle for cutting linoleum and similar materials. The blade is not symmetrical with respect to its first opening. It has one end located at a greater distance from the first opening, and is inclined to the longitudinal axis of the blade at a greater angle than the opposite end. The blade may thus be mounted in the holder in a plurality of alignments which provide different lengths of exposed cutting edge and different degrees of blade rigidity. The blade may further be provided with a second opening so that the locating pin may be passed through the second opening while one end edge of the blade abuts one side of the recess in the second part. When so mounted the blade projects downwardly at an angle from the holder. The blade is in-line with the handle and not transversely angled and rigidly mounted.
U.S. Pat. No. 3,107,426 to Robinson, Jr. discloses a utility knife having a knife blade adapted for slidable movement between a safety position within the knife handle and an extended cutting position. The knife comprises an elongated handle having a blade-receiving slot at one of the ends thereof. The handle comprises two elongated members detachably secured and separable along a longitudinal plane extending rearwardly from the slot opening. A carrier is reciprocally mounted on one of the elongated members for movement toward and away from the slot opening. A blade is supported on the carrier and has parallel edges that engage side flanges extending from the base of the carrier. An elongated tongue extends rearwardly from the carrier and engages a locking cam surface on the handle. A button is fixed to the tongue and may be depressed to move the tongue out of engagement with the locking cam surface, and to slidably reciprocate the tongue within the handle. The knife may further comprise a compartment for storage of spare blades. The members of the handle are secured by a screw. Significantly, the knife blade retraction mechanism requires that the blade and the inside surfaces of the handle halves be substantially coplanar. The knife, therefore, lacks transverse blade angulation.
U.S. Pat. No. 3,324,548 to Mascia discloses a tool-holding knife comprising a handle, a bifurcated tool holder, and blade. The knife is said to be especially useful for cutting linoleum, vinyl, carpeting, and the like. The tool holder is provided with two branches, spaced apart by rivets which also serve to buttress various of the blades which are usable with the tool holder and appointed to be situated between the branches. Several positions are described for mounting the blades in the holder, including a straight knife position, a generally perpendicular scraping position, and a downwardly angled position for cutting linoleum or the like. A blade must be inserted between two closely spaced branches of the device and is held by friction. Here again the blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 3,380,159 to Winston discloses a cutting device for opening shipping containers and the like of cardboard or similar material. The cutting device is designed to prohibit the damage of merchandise contained therein. The device is preferably formed of two flat sheets of heavy gage sheet metal pivotally affixed to one another at one end by a pivot pin. The sheets are formed to provide oppositely disposed cavities between them for storage of spare cutting blades. The ends of the sheets opposite the pivoted end are formed to provide a cutting blade retainer. The edges of the sheets form a straight edge on the retainer, which is angularly disposed with respect to the handle to provide a clearance for the knuckles and fingers of a user of the cutting device. The cutting blade retainer has a recessed blade cavity of substantially the same depth and width as the thickness and width, respectively, of a cutting blade seated in the retainer. A shoulder bolt is inserted through aligned apertures in the blade and the sheets, and engages a nut to fasten the blade and sheets together. The end of one of the sheets further comprises an extended end formed to provide a runner support and a runner extending below and substantially perpendicular to the runner support and in a parallel spaced relationship to the straight edge, thereby forming a slot. The runner preferably has a semi-round cross-section to give it sufficient strength to pierce cardboard without buckling or flexing. The runner also has an outwardly curved surface facing away from the slot to provide protection for the merchandise contained within the shipping container by allowing only a minimal amount of the runner to be in touch with the merchandise Significantly, the runner structure of the knife limits the extent of blade penetration and thus severely limits the utility of the knife for glazing and similar operations wherein a blade is expected to penetrate to a substantial depth perpendicular to the cutting surface. Moreover, the lack of transverse angulation of the in-line cutting blade further restricts suitability of the device for outside cutting operations.
U.S. Pat. No. 3,906,625 discloses a utility knife comprising a handle and a blade removable therefrom. The handle comprises a sleeve-like handle member having a cavity portion therein and a blade carrier member. The cavity portion comprises a longitudinal slot with the handle being open at its base and at one end of the slot. The carrier is pivotally mounted to the handle at the other end thereof opposite from the open slotted end for pivotal movement into and out of the cavity. The carrier has a longitudinal extent substantially equivalent to that of the longitudinal handle and has a plurality of studs at its end adapted to support a perforated cutting blade in a plurality of orientations relative to the handle. The blade carrier also comprises an integral, resilient clip portion for fixedly holding replacement blades for storage and resilient protrusions, which assist in holding the blade carrier within the handle in the closed position. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 4,575,940 to Wenzel discloses a carpet layer's knife having a handle and blade holder for demountably securing a heavy-duty, razor-style blade having two generally parallel sharpened edges and an open center section with a slot elongated in a direction parallel the sharpened edges, for mounting the blade in the handle. The holder comprises two body sections, which part along a medial longitudinally extending plane. The body sections have blade-holding portions at one end. A screw connecting means, which tightens to clamp the blade between the blade holding portions, connects the body sections. A shoulder formed in the blade-holding portion of one of the body sections passes through the center slot in the blade and provides support against rotation of the blade in its plane during use of the knife. Resilient means comprising a spring, surrounds the screw connecting means to urge the body sections apart when the screw connecting means is loosened, thereby facilitating insertion and removal of blades. The screw connecting means is provided with a manually engageable extension such as a D-ring for applying torque to the screw without necessity of an additional tool, such as a screwdriver, when changing blades. A blade compartment may be provided for storage of spare blades. Significantly, the knife is angulated longitudinally: the blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 4,713,884 to Dunnagan discloses a hand-held knife for use in cutting carpet pads. The knife comprises a handle having a pair of handle members generally abutting at a median plane, a blade is positioned therebetween, and a releasable fastener clamps the handle members together and secures the blade. The use of the knife depicted is said to reduce the propensity of carpet pad to wrinkle while being cut, thereby improving the accuracy of the cut and decreasing the fatigue experienced by the carpet pad installer. The knife comprises a handle portion, a forwardly projecting blade support portion formed at generally an angle of 30 to 45 degrees with respect to the long dimension of the handle, and a heel at the transition between the portions. A raised boss present on the inside surface of one of the blade support portions of the right side member of the handle is sized to be received in a longitudinal slot present in a knife blade of conventional design. The orientation of the boss establishes the angle of the blade cutting edge with respect to the handle. A thumbwheel having a threaded extension penetrates an aperture in one half of the handle generally at its heel and engages a corresponding internally threaded aperture in the opposite handle half to clamp the halves together and secure the blade in position. The handle members may optionally comprise a storage compartment for spare knife blades. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 4,884,342 to McNamara et al. discloses a cutting device including a handle and a blade particularly adapted for cutting wallpaper. The handle is elongated and comprises two half-handles secured together. At least one of the half-handles has a lengthwise internal passageway in its sidewall and at least one of the half-handles has a lengthwise external opening in its sidewall, the opening and the passageway being at least partially coextensive. An elongated blade is slidably and retractably mounted between the sidewalls and is extendable from the front end of the handle. A protruding member is slidably mounted within the internal passageway and is removably fixed to the blade. A biasing means is positioned against the blade to hold the blade against the protruding member. A releasing means is provided for moving the blade laterally against the biasing means so as to allow the blade to be released from the protruding member, thereby facilitating replacement of the blade. An adjustment means slidably mounted in the opening allows the extension of the blade from the handle to be varied. A roller means is situated at the front end of the handle to guide the blade along a cutting path. A guidance mechanism is rotatably connected to the handle. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 5,014,429 to McNamara discloses a utility knife including a mechanism for detaching individual segments from a segmented knife blade. The knife includes a housing having two mating, spaced side wall portions with a channel therein to house and guide a blade. One end of the channel terminates within the housing, while the other end opens to form an exit slot from which the blade may protrude. An adjustment mechanism is disposed for back and forth sliding movement within a slot in the sidewall. A boss is provided on the adjustment mechanism to engage an aperture in the blade. One of the sidewalls also has a recess to accommodate a spring member which provides a force both to bias the blade against the opposite side wall portion, thereby presenting rattling or lateral displacement of the blade, and to bias the blade against the adjustment member to maintain engagement of the boss with the blade. The sidewall further accommodates a mechanism to allow individual segments to be severed from the blade and capture the severed piece in a safe manner for disposal. The mechanism comprises a transversely oriented plunger which, when depressed against the blade, causes fracture of the blade along a pre-formed segmentation line. Opposite the plunger in one of the sidewalls is a recess appointed to receive the severed blade segment, thereby restraining it from flying away from the knife uncontrollably. An aperture is provided in the recess, from which the severed segment may be removed at the user's convenience. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade
U.S. Pat. No. 5,241,750 to Chomiak discloses a utility razor safety knife having a handle and a blade and a blade guard attached thereto. The blade guard comprises an open-bottomed hood pivotally secured to the handle by a screw and biased to the closed position by springs whose bottom ends terminate on footing rests on the sides of the yoke and whose top ends engage a yoke attached to the top of the handle. The screw also acts to secure the blade between complementary halves of the handle. In the closed position, the blade guard both protects the user from the blade cutting edge and protects the blade from being inadvertently nicked or dulled. The knife is used by grasping the handle and pressing the open side of the hood into the article to be cut, thereby causing retraction of the biasing springs and exposure of the blade edge. The footing rests serve to maintain the blade generally perpendicular to the surface being cut and to limit the depth of penetration of the blade. After completion of the cut and withdrawal of pressure on the handle, the springs again urge the blade guard into the closed position. The knife lacks transverse angulation of its blade. In addition, the blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 5,490,331 to Gold provides a utility knife adapted both for cutting and scraping. The knife is provided with a retractable blade having a sharpened bottom edge for cutting and a sharpened front edge for scraping. A holder comprises two half-hand grips secured by a screw having a threaded shank and a large diameter cylindrical knurled head. Preferably the head extends laterally of the knife approximately 0.5 inch when tightened to provide additional grip when the knife is drawn rearwardly during cutting use of the knife. The holder is further provided with a downwardly projecting, finger-contacting member which serves as a stop for the user's hand when the knife is being forwardly pushed, as during a scraping stroke of the knife. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 5,890,294 to Keklak et al. discloses a locking safety utility knife that includes a body and an operating lever, which is squeezed to deploy a retractable cutting blade from within the body. The blade can be locked in its retracted position by means of a ratchet-like mechanism including a pawl adapted to be released by manipulating a cam operator. The pawl engages teeth formed on the outside of a door, which closes the rear of a compartment formed in the operating handle to house spare blades. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 5,906,049 to Butts discloses a double-ended utility knife with a blade at each of its ends. The two blades are independently reciprocally extendible from respective compartments within the body of the knife and may be of different shapes. The knife comprises a generally rectangular base member having a front side and a backside and front and back covers adapted to be attached to the front and backsides. Each of the covers extends less than the total length of the base member. The provision of separate covers partially covering the respective front and back sides of the base member allows either of the blades to be changed independently without exposing the other and possibly allowing it to be inadvertently dislodged. Each of the blades extendible from the knife is coplanar with the base member of the knife. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 5,940,970 to D'Ambro, Sr., et al. discloses a utility knife including a holder having two mating halves, a first cavity at a proximal end of the holder for receiving a blade for active use and a second cavity located toward a distal end of the holder for receiving and storing a supply of replacement blades. The mating halves are joined by a hinge at the distal end of the holder and a captive screw closure extending between the mating halves at a position intermediate the first and second cavities. The first cavity incorporates a magnet for engaging the active blade, while the second cavity incorporates a magnet for additionally engaging one or more replacement blades. The knife blade in the patented utility knife is situated generally coplanarly with the mating interior surfaces of the halves of the blade holder. Hence, the blade extends straight from the holder without angulation. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
U.S. Pat. No. 6,192,589 to Martone et al. discloses a utility knife including a main body, a blade holder assembly movably mounted within the body, and a manually engageable member slidably mounted on the main body. The blade holder is movable between a retracted position wherein the blade is disposed within the body and an extended position wherein the blade protrudes outwardly from the main body to enable a cutting operation. The manually engageable member is operatively connected with the blade holder assembly and is movable to extend and retract the blade holder assembly. The utility knife further comprises a blade storage member pivotally connected with the main body. The blade storage member is appointed to carry a supply of spare blades. The utility knife also includes a locking structure constructed and arranged to releasably lock the blade storage member in its closed position. Significantly, the knife blade retraction mechanism requires that the blade and the inside surfaces of the handle halves be substantially coplanar. The blade is in-line with the handle and lacks rigid mounting needed for an angled blade.
Utility knifes of various kinds, which have been described and used by prior art workers, all place the knife in-line with the handle and minimize protrusion of the knife to reduce blade breakage. Any angulation suggested is within the plane formed by the handle and the plane of the knife. This arrangement of the knife components fails to solve a troublesome problem encountered by glaziers and sheet rock workers, namely the need to make perpendicular cuts in tight corners. Such cuts require long blade lengths and close placement of a worker's hand in tight corners increasing the risk of injury. An in-line placement of blade and handle prevents a close approach of the knife to the wall edge, due to the size of the worker's hand and in-line location of the blade; it clearly increases the risk of injury.
Key factors that would be desirable when constructing a utility knife for glaziers include transverse angulation to prevent the worker's hand from being in the path of the blade. The transverse angulation would also permit closer knife approaches to corners. It would enable maintenance of a vertical cut and provide adequate blade support to minimize breakage of the angled blade, which encounters substantial pressure during use. However, structures which provide the functionality requisite for achieving these key factors have not previously been proposed by prior art workers.
As a consequence remains a need in the art for a utility knife for glaziers and sheet rock workers, which provides transverse angulation and adequate blade support. Also there is need for knifes usable by left-handed and right-handed users. This need has heretofore not been met by conventional utility knives.