CA1216455A - Imaging system - Google Patents
Imaging systemInfo
- Publication number
- CA1216455A CA1216455A CA000445389A CA445389A CA1216455A CA 1216455 A CA1216455 A CA 1216455A CA 000445389 A CA000445389 A CA 000445389A CA 445389 A CA445389 A CA 445389A CA 1216455 A CA1216455 A CA 1216455A
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- Canada
- Prior art keywords
- curing agent
- composition
- photosensitive composition
- coating composition
- imaging sheet
- Prior art date
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Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/002—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor using materials containing microcapsules; Preparing or processing such materials, e.g. by pressure; Devices or apparatus specially designed therefor
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- General Physics & Mathematics (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
Abstract
IMPROVED IMAGING SYSTEM
ABSTRACT
Means are provided for preventing image diffusion :
in images formed by imagewise exposure of a microencapsulated photosensitive material to actinic radiation, followed by a color forming reaction between a chromogenic material and a developer. A curing agent for the photosensitive composition, such as an organic peroxide, is microencapsulated separately from the photosensitive material and included in the coating. When the capsules are ruptured, the released curing agent reacts with the photosensitive material and thereby stabilizes the formed color so that its quality will not deteriorate over time.
ABSTRACT
Means are provided for preventing image diffusion :
in images formed by imagewise exposure of a microencapsulated photosensitive material to actinic radiation, followed by a color forming reaction between a chromogenic material and a developer. A curing agent for the photosensitive composition, such as an organic peroxide, is microencapsulated separately from the photosensitive material and included in the coating. When the capsules are ruptured, the released curing agent reacts with the photosensitive material and thereby stabilizes the formed color so that its quality will not deteriorate over time.
Description
MEAA:044 IMPROVED IMAGING SYSTEM
The present invention relates to the production of photographs, photocopies, or other fixed images. Mor~
specifically, it is an i~aging sy~em which employs a coated substrate whi~h contains a chromogenic ma~erial and a mic~oencapsulated photosensiti~e composition. In the most preferred embodimen of this invention the chromogenic material and photosensi~ive composition are in the same microcapsules~
Several known imagi~g ~ystems employ photosensi~ive encapsulates. One such imaging syste~
which has significant advan~ages over all previou~ly known -ones is referred to generically as the Sanders process.
This process employs a coating composition which is usually applied to a substrate. The coating includes a photosensitive composition which is encapsula~ed and a chromogenic material which may or may not ~e within the microcapsules. (~Encapsulat~d~ is used herein to refer to bo~h open phase systems in ~hi~h the photosensitive composition is dispersed as droplets throughout ~
dispersing medium and sys~ems in which there is a discre~e capsular wall.) The microcapsules generally ha~e a mean - -diameter of 1 to 25 microns~ Images aee formed by imagewise exposure of ~he coating composition ~o actini~
radiation. ~Actinic radiation~ i5 used herein ~o
The present invention relates to the production of photographs, photocopies, or other fixed images. Mor~
specifically, it is an i~aging sy~em which employs a coated substrate whi~h contains a chromogenic ma~erial and a mic~oencapsulated photosensiti~e composition. In the most preferred embodimen of this invention the chromogenic material and photosensi~ive composition are in the same microcapsules~
Several known imagi~g ~ystems employ photosensi~ive encapsulates. One such imaging syste~
which has significant advan~ages over all previou~ly known -ones is referred to generically as the Sanders process.
This process employs a coating composition which is usually applied to a substrate. The coating includes a photosensitive composition which is encapsula~ed and a chromogenic material which may or may not ~e within the microcapsules. (~Encapsulat~d~ is used herein to refer to bo~h open phase systems in ~hi~h the photosensitive composition is dispersed as droplets throughout ~
dispersing medium and sys~ems in which there is a discre~e capsular wall.) The microcapsules generally ha~e a mean - -diameter of 1 to 25 microns~ Images aee formed by imagewise exposure of ~he coating composition ~o actini~
radiation. ~Actinic radiation~ i5 used herein ~o
- 2 designate the entire spectrum of ele~tromagneti~
radiationO3 ~Imagewise~ exposure means tha~ radia ion is _ applied in a pat~ern such that areas which are t~ be dark receive the most radiation while areas which are ~o be ligh~ receive little or no radia~ion~ ~r vice versa. This can be accomplished, for example, by placing a s~encil between ~he radia~ion source and ~he coa ing. Exposure can be through either dir~ct transmission or reflection imaging.
After exposure, the ~icrocapsules, or at leas~
those in the image areas, c~n be rup~ured by calendering or other suitable means. In the ~ase of a photohardenable photosensitive composition, the viscosity of the photosensitive composition i5 increased ~ubs~antially upon exposure to actinic radiation, through mechanisms such as cross-linking or simple polymeÆization. Therefore, when the capsules are broken, the photosensitive composition which received a strong exposure will flow very little, if at all, while the unexposed or weakly exposed photosensitive composition can flow relatively freely. As a direct result, the chromogenic materi~l react~ imagewise with the developer according to ~he degree of exposure to form a color in the form of the desired image. This can occur several different ways.
In one embodiment, ~he chromogenic material i5 encapsulated with the photosensitive composition. Outside the capsules, a developer is contained in ~he co~ing, whi~h is applied to a sub~trate. When the ~apsules are _~-ruptured~ the chormogenic material is available to flow, but its movement from the exposed capsules is restricted by the increased viscosity of the photosensitive 5~
compositions in those capsules. ~s a resul~, the accessibility of chromogenic material ~o developer depends on the exposure rec~ived locally. The developer and chromogenic material react according to the exposure to form the desired image. When this embodiment of a coating composition is applied to a substra~e, the result is a self-contained imaging sheet.
In another embodiment, the photosensitive composition is encapsulated and the chromo~enic material is wi~hin the coating inside or outside ~he ~apsules. A
developer can be located as a separate layer rom the chormogenic material in the coating, or can be on a separate substrate altogether. In the ormer situation, capsule rupture releases imagewise the photosensitive composition. The chromogenic material now reacts wi$h the developer to form a color generally in the form o an image. In the lat~er situation~ the ~wo substrates are superimposed during capsule rupture so that the dissolved chromogenic material flows onto the developer sheet and reacts imagewise there.
In an alternative embodiment, the photosensitive composition can be a high viscosity substance which depolymerizes upon exposure to actinic radiation. In that case~ the chromogenic material located in or near expos~d capsules, instead of unexposed ones, i~ made accessible ~o the developer. This changes the imaging system Erom a posi~ive one to a negative one.
The photosensitive composition includes a ---photoinitiator and a substance which undergoes a change in viscosity upon exposure to light in the presence ~f the photoinitiator. That substance may be a monomer, dimer, ~ ~, or oligomer which is polymerized to a higher molecular weight compound or it may be a polymer which is - cross-linkedO Alternatively i~ may be a compound which is depolymerized or oth~rwis~ lysed upon exposu~e. ~adia~ion curable material~ that are often used are matexials curable by free radical initiated chain propagated addition polymerization or ionic polymeriza~ion.
Representative radiation curable ~aterial are ethylenically unsaturated organic compounds. These compounds contain at least one terminal ethylenic group per molecule. Typi~ally they are liquid at room temperature and can also double as a carrier oil .or the chromogenic material in ~he internal phase. A preferred group of radiation curable materials is ethylenically unsaturated compounds having two or more ~erminal ethylenic groups per molecule~ Representative examples of these compounds include ethylenically unsaturated acid esters of polyhydric alcohols such as trimethylol propane triacrylate or trimethacrylate7 acrylate prepolymers derived from the partial reaction of pentaerythritol with acrylic or methacrylic acid or acrylic or me~hacrylic acid esters; isocyanate modified acrylate, methacrylic and itaconic acid esters of polyhydric alcohols, etc.
Some typical examples of photosoftenable 2s materials useul in other embodiments are photolysable compounds such as certain diazonium compounds,
radiationO3 ~Imagewise~ exposure means tha~ radia ion is _ applied in a pat~ern such that areas which are t~ be dark receive the most radiation while areas which are ~o be ligh~ receive little or no radia~ion~ ~r vice versa. This can be accomplished, for example, by placing a s~encil between ~he radia~ion source and ~he coa ing. Exposure can be through either dir~ct transmission or reflection imaging.
After exposure, the ~icrocapsules, or at leas~
those in the image areas, c~n be rup~ured by calendering or other suitable means. In the ~ase of a photohardenable photosensitive composition, the viscosity of the photosensitive composition i5 increased ~ubs~antially upon exposure to actinic radiation, through mechanisms such as cross-linking or simple polymeÆization. Therefore, when the capsules are broken, the photosensitive composition which received a strong exposure will flow very little, if at all, while the unexposed or weakly exposed photosensitive composition can flow relatively freely. As a direct result, the chromogenic materi~l react~ imagewise with the developer according to ~he degree of exposure to form a color in the form of the desired image. This can occur several different ways.
In one embodiment, ~he chromogenic material i5 encapsulated with the photosensitive composition. Outside the capsules, a developer is contained in ~he co~ing, whi~h is applied to a sub~trate. When the ~apsules are _~-ruptured~ the chormogenic material is available to flow, but its movement from the exposed capsules is restricted by the increased viscosity of the photosensitive 5~
compositions in those capsules. ~s a resul~, the accessibility of chromogenic material ~o developer depends on the exposure rec~ived locally. The developer and chromogenic material react according to the exposure to form the desired image. When this embodiment of a coating composition is applied to a substra~e, the result is a self-contained imaging sheet.
In another embodiment, the photosensitive composition is encapsulated and the chromo~enic material is wi~hin the coating inside or outside ~he ~apsules. A
developer can be located as a separate layer rom the chormogenic material in the coating, or can be on a separate substrate altogether. In the ormer situation, capsule rupture releases imagewise the photosensitive composition. The chromogenic material now reacts wi$h the developer to form a color generally in the form o an image. In the lat~er situation~ the ~wo substrates are superimposed during capsule rupture so that the dissolved chromogenic material flows onto the developer sheet and reacts imagewise there.
In an alternative embodiment, the photosensitive composition can be a high viscosity substance which depolymerizes upon exposure to actinic radiation. In that case~ the chromogenic material located in or near expos~d capsules, instead of unexposed ones, i~ made accessible ~o the developer. This changes the imaging system Erom a posi~ive one to a negative one.
The photosensitive composition includes a ---photoinitiator and a substance which undergoes a change in viscosity upon exposure to light in the presence ~f the photoinitiator. That substance may be a monomer, dimer, ~ ~, or oligomer which is polymerized to a higher molecular weight compound or it may be a polymer which is - cross-linkedO Alternatively i~ may be a compound which is depolymerized or oth~rwis~ lysed upon exposu~e. ~adia~ion curable material~ that are often used are matexials curable by free radical initiated chain propagated addition polymerization or ionic polymeriza~ion.
Representative radiation curable ~aterial are ethylenically unsaturated organic compounds. These compounds contain at least one terminal ethylenic group per molecule. Typi~ally they are liquid at room temperature and can also double as a carrier oil .or the chromogenic material in ~he internal phase. A preferred group of radiation curable materials is ethylenically unsaturated compounds having two or more ~erminal ethylenic groups per molecule~ Representative examples of these compounds include ethylenically unsaturated acid esters of polyhydric alcohols such as trimethylol propane triacrylate or trimethacrylate7 acrylate prepolymers derived from the partial reaction of pentaerythritol with acrylic or methacrylic acid or acrylic or me~hacrylic acid esters; isocyanate modified acrylate, methacrylic and itaconic acid esters of polyhydric alcohols, etc.
Some typical examples of photosoftenable 2s materials useul in other embodiments are photolysable compounds such as certain diazonium compounds,
3-oximino-~-butanone methacrylate which undergoes main chain scission upon U.V. exposure and poly 4'-alkyl - .
acylo-phenones~
Various photoinitiators are used. These compounds absorb ~he exposure radiati~n and generate a free radical alone or in conjunction with a sensitizer.
Suitable photoinitiators include ~-alkoxy phenyl ketones, Michler's ketone, O-acylated ~-oximinoketones, polycyclic quinones, benzophenones and substituted benzophenones, xanthones, thioxanthones, halogenated compounds such as chlorosulfonyl and chloromethyl polynuclear aromatic compounds, chlorosulfonyl and chloromethyl heterocyclic compounds, chlorosulfonyl and chloromethyl benzophenones and fluorenones, haloalkanes, ~-halo-~-phenylacetophenones photoreducible dye-reducing agent redox couples, halo-genated paraffins (e.g. bromina-ted or chlorinated paraffin) benzoin alkyl ethers, etc.
The above described embodiments are only a few of the possible variations on the Sanders process. The means and methods of each comprise an imaging system which has substantial practical, commercial and functional advantages over prior art imaying systems. Various aspects of this process are disclosed in the following U.S. Patent No.
acylo-phenones~
Various photoinitiators are used. These compounds absorb ~he exposure radiati~n and generate a free radical alone or in conjunction with a sensitizer.
Suitable photoinitiators include ~-alkoxy phenyl ketones, Michler's ketone, O-acylated ~-oximinoketones, polycyclic quinones, benzophenones and substituted benzophenones, xanthones, thioxanthones, halogenated compounds such as chlorosulfonyl and chloromethyl polynuclear aromatic compounds, chlorosulfonyl and chloromethyl heterocyclic compounds, chlorosulfonyl and chloromethyl benzophenones and fluorenones, haloalkanes, ~-halo-~-phenylacetophenones photoreducible dye-reducing agent redox couples, halo-genated paraffins (e.g. bromina-ted or chlorinated paraffin) benzoin alkyl ethers, etc.
The above described embodiments are only a few of the possible variations on the Sanders process. The means and methods of each comprise an imaging system which has substantial practical, commercial and functional advantages over prior art imaying systems. Various aspects of this process are disclosed in the following U.S. Patent No.
4,399,209 and Canadian Patent Applications Serial No. 409,388 and 409,389.
After exposure and capsule rupture, -the oil phase (i.e., the photosensitive composition and the chromogenic material) migra-tes to the developer layer which is on the same substrate as the microcapsules in a self-contained imaging sheet and on a separate substrate in a transfer sheet.
Some of the color formed is retained in the photosensitive oil phase in a mobile solution after image ~ .
formation. Thl5 i5 particularly true where large amounts of heavier photosensitive oils form the internnl phase.
If the: pho~osens1~ive composition does not quickly react to visible ligh~ followlng capsule rupture ana image formation9 in some cases the image may bleed dswn into and across the imaging shee~, blurring and reducing ~he intensity of the image. This effect $s ~ometimes referred ~o as ~featheringr.
The present invention solves the problem of image diffusion in the Sanders process imaging system by including an agent in the coating composition which reacts with the photosensitive composition released from the microcapsules following exposure (more particularly the photohardenable or photosof~enable species) and cures or otherwise hardens it. This agent Ihereinafter referred to as ~a curing agent~) is typically a free radical generating species such as a thermal initiator. While one might expec~ that the photosensitive composition released from the microcapsules in the image areas could be hardened by a subse~uent exposure with actinic radiation, this has not been found to be effective~ ~n instances where image diffusion occurs, it has been found desirable to incorporate a curing agent in the composition for subsequent reaction with ~he released photosensitive composition.
In one aspect, the invention pertains to a coating eomposition for use in photoimaging the coating composition comprising a chromogenic material, rupturable microcapsules whieh contain a photosensitive composition, and a curing agent. The coating composition is characterized in that - 6a - f images are formed by imagewise exposing a coating of the composition to actinic radiation and rupturing the micro-capsules in the image areas such that the chromogenic material can react with an associated co-reactive developer material to form a color image. The curing agent reacts with the photosensitive composition following capsule rupture and hardens the same to provide image stability upon aging.
Another aspect of the invention pertains to an imaging sheet comprising a substrate, with such coating composition on cne surface of the substrate. The imaging sheet is characterized in that images are formed by imagewise exposing the substrate to actinic radiation and rupturing the micro capsules in the image areas such that the chrpmogenic material reacts with a co-reactive developer material associated with the imaging sheet. The curing agent reacts with the photosensitive composition released from the capsules to improve image stability upon aging.
The curing agent is preferably encapsulated. It may be contained in the same capsules as the photosensitive composition or in separate photoinert capsules. The latter is preferred. If included in the `;`
same photoactiYe capsules, the effect will be the same at first, but precuring of the capsule conten s ~y begin to _occur in some cases, and all photosensitiYi~y may be lost in a few days. An inert oil carrier ean be included in S the capsules containing the ~uring agent to facilita~e `~ flow and curing on rupture, ~ he curing agent is preferabl~ selec~ed on the basis of shelf-lifet reactivity with ~he pho~osensitive composition, lack of solubility in water, solubility in an 1~ inert oil carrier, low hydrolysis ra~e in the presence of water phases having a pH ranging from about 3.5 to 9.5, ease of encapsulation, and other ch~racteristics consistent with known encapsulation techniques.
By exposing a coating of the composition, lS rupturing the capsules alone (in the case of a self-contained system) or in contact with a developer shee~, and preferably heating th~ image to activate ~he curing agent oe accelera~e curing, ~able images can be formed. The chromogenic material reacts with the 2Q developer ~o form a color image and the curing agent hardens the photosensitive composition released from the capsules to prevent image diffusion.
Besides greatly reducing image diffusion, ~his will improve smudge resistance and solvent resistance and make the images more scuff proof.
The present invention is an improvemen~ of an imaging ~ystem which employs a coating of a microencapsulated photosensi~ive composition, a chromogenic material which may or may not be inside ~he capsule3, and a developer which c~n be ~n luded ~n the coating or provided on a separa~e substra e wherein images are ~ormed by imagewi~e exposing the coated substrate to ac~inic radi~tion and ~hen rupturing the capsulesO I the deYeloper is on ~ separa~e substr~te, the two ~ubstrates ~re superimposed while the capsules are ruptured. In these systems after the image develops, some color remains dissolved in the photosensitive phase released from the capsules, and can bleed through and across the substrate, ha~ming imaqe definition and intensity unless ~he photosensitive pha~e is reacted~
The preferred embodiment of this invention comprises including ~ chemical ~essen~ially non-photosensitive) curing agent for the photosensitive composit$on in the coat~ng composition. The function of the curing age~t is to cure the photosensitive ~o~position after developing. Once the color has been fsrmed, ~he rapid hardening of the photosensitive composition prevents over~development and difusion~ The chemically cured photosensitive composition is thus ~frozen~ and the color remains in place a~d does not diffuse. The curing agent is suitably encapsulated with an inert carrier in capsules separate from those containing the photosensitive composition. Maintaining separate encapsulation prevents precuring, which could interfere wi h the imaging system's photosensitivity in a matter of days.
Selecting the curing agent and inert carrier oil for encapsulation requires consideration of the capsule wall material, conditions prevailinq in the waterless phase outside the capsules~ and storage temperatures.
Further bases for selecting a curing ~gent include lack o
After exposure and capsule rupture, -the oil phase (i.e., the photosensitive composition and the chromogenic material) migra-tes to the developer layer which is on the same substrate as the microcapsules in a self-contained imaging sheet and on a separate substrate in a transfer sheet.
Some of the color formed is retained in the photosensitive oil phase in a mobile solution after image ~ .
formation. Thl5 i5 particularly true where large amounts of heavier photosensitive oils form the internnl phase.
If the: pho~osens1~ive composition does not quickly react to visible ligh~ followlng capsule rupture ana image formation9 in some cases the image may bleed dswn into and across the imaging shee~, blurring and reducing ~he intensity of the image. This effect $s ~ometimes referred ~o as ~featheringr.
The present invention solves the problem of image diffusion in the Sanders process imaging system by including an agent in the coating composition which reacts with the photosensitive composition released from the microcapsules following exposure (more particularly the photohardenable or photosof~enable species) and cures or otherwise hardens it. This agent Ihereinafter referred to as ~a curing agent~) is typically a free radical generating species such as a thermal initiator. While one might expec~ that the photosensitive composition released from the microcapsules in the image areas could be hardened by a subse~uent exposure with actinic radiation, this has not been found to be effective~ ~n instances where image diffusion occurs, it has been found desirable to incorporate a curing agent in the composition for subsequent reaction with ~he released photosensitive composition.
In one aspect, the invention pertains to a coating eomposition for use in photoimaging the coating composition comprising a chromogenic material, rupturable microcapsules whieh contain a photosensitive composition, and a curing agent. The coating composition is characterized in that - 6a - f images are formed by imagewise exposing a coating of the composition to actinic radiation and rupturing the micro-capsules in the image areas such that the chromogenic material can react with an associated co-reactive developer material to form a color image. The curing agent reacts with the photosensitive composition following capsule rupture and hardens the same to provide image stability upon aging.
Another aspect of the invention pertains to an imaging sheet comprising a substrate, with such coating composition on cne surface of the substrate. The imaging sheet is characterized in that images are formed by imagewise exposing the substrate to actinic radiation and rupturing the micro capsules in the image areas such that the chrpmogenic material reacts with a co-reactive developer material associated with the imaging sheet. The curing agent reacts with the photosensitive composition released from the capsules to improve image stability upon aging.
The curing agent is preferably encapsulated. It may be contained in the same capsules as the photosensitive composition or in separate photoinert capsules. The latter is preferred. If included in the `;`
same photoactiYe capsules, the effect will be the same at first, but precuring of the capsule conten s ~y begin to _occur in some cases, and all photosensitiYi~y may be lost in a few days. An inert oil carrier ean be included in S the capsules containing the ~uring agent to facilita~e `~ flow and curing on rupture, ~ he curing agent is preferabl~ selec~ed on the basis of shelf-lifet reactivity with ~he pho~osensitive composition, lack of solubility in water, solubility in an 1~ inert oil carrier, low hydrolysis ra~e in the presence of water phases having a pH ranging from about 3.5 to 9.5, ease of encapsulation, and other ch~racteristics consistent with known encapsulation techniques.
By exposing a coating of the composition, lS rupturing the capsules alone (in the case of a self-contained system) or in contact with a developer shee~, and preferably heating th~ image to activate ~he curing agent oe accelera~e curing, ~able images can be formed. The chromogenic material reacts with the 2Q developer ~o form a color image and the curing agent hardens the photosensitive composition released from the capsules to prevent image diffusion.
Besides greatly reducing image diffusion, ~his will improve smudge resistance and solvent resistance and make the images more scuff proof.
The present invention is an improvemen~ of an imaging ~ystem which employs a coating of a microencapsulated photosensi~ive composition, a chromogenic material which may or may not be inside ~he capsule3, and a developer which c~n be ~n luded ~n the coating or provided on a separa~e substra e wherein images are ~ormed by imagewi~e exposing the coated substrate to ac~inic radi~tion and ~hen rupturing the capsulesO I the deYeloper is on ~ separa~e substr~te, the two ~ubstrates ~re superimposed while the capsules are ruptured. In these systems after the image develops, some color remains dissolved in the photosensitive phase released from the capsules, and can bleed through and across the substrate, ha~ming imaqe definition and intensity unless ~he photosensitive pha~e is reacted~
The preferred embodiment of this invention comprises including ~ chemical ~essen~ially non-photosensitive) curing agent for the photosensitive composit$on in the coat~ng composition. The function of the curing age~t is to cure the photosensitive ~o~position after developing. Once the color has been fsrmed, ~he rapid hardening of the photosensitive composition prevents over~development and difusion~ The chemically cured photosensitive composition is thus ~frozen~ and the color remains in place a~d does not diffuse. The curing agent is suitably encapsulated with an inert carrier in capsules separate from those containing the photosensitive composition. Maintaining separate encapsulation prevents precuring, which could interfere wi h the imaging system's photosensitivity in a matter of days.
Selecting the curing agent and inert carrier oil for encapsulation requires consideration of the capsule wall material, conditions prevailinq in the waterless phase outside the capsules~ and storage temperatures.
Further bases for selecting a curing ~gent include lack o
5~
solubility in water, solubility in the inert carrier oil (which itself should be compatible with the oil phase in the photosensitive composition~s capsuiès) a relatively low hydrolysis rate in water phases having a pH between 3.5 and 9.5 for up to two hours at 40 to 50C, ease of encapsulation, and other considerations with respect to encapsulation. It is important that the encapsulated curing agent have an adequate shelf life.
~referred curing agents are free radical generators such as thermal initiators, which upon reacting with the photosensitive composition cause it to polymerize or crosslink. By exposing the coating composition to actinic radiation, and rupturing the capsules in the presence of a developer material, the chromogenic material and the developer react to produce color in the form of an in~age and the curing agent reacts with the photosensitive composition and ~ardens it, thereby preventing image diffusion. In the case of certain curing agents, lt may be desirable to heat the image to accelera-te the cure. A
curing agent is preferably selected which is relatively inactive at room temperature Ifor good shelf life) and which is readily activated by heating to tempera-tures in excess of room temperature.
A particularly useful class of thermal initiators reactive with ethylenically unsaturated compounds are organic peroxides. Suitable peroxides include diacyl peroxides, ketone peroxides, peroxydicarbonates, alkyl peroxides, alkyl hydroperoxides and sulfonyl peroxides.
Also useful as thermal initiators are bisazides, perborates and diazo compounds.
`,.
~2~ 35 Carrier oil~ conventionally use~ in forming pressure-sensi~ive microcapsules can be used in the preserlt invention provided they are essentially ~nert to the curing agent. Deodorized kero~ense, alkylated 5 biphenyls and alkylated ph~chalates are examples,.
The encapsulation proce~s s:hosen mu~t give a high yield of thermal initiator retained over extended periods of storage, wheSher in water dispersions or after being applied to a subs~rate~ Also, the temperature during manufacture and storage mu~t be maintained below levels tha~ would cause rapid deeomposition of ~he ~hermal initiator~ For this reason, ini~iators which are no~
activated below about 25C are preferably used~
In some situations, peroxides can pre ent a fir~
lS hazard~ Th~s problem can be avoided by limi~ing the amount used~ Preferably, the amount of peroxide used should equal abou~ 0.1 ~o 1.0 percent of ~he weight of photQsensitive composition used. Thus, if three pounds of photosensitive composi~ion ~apsules are used fOE 3, 300 square feet of ~ubstrate paper7 only 0.03 pounds of peroxide would be present at th~ 1~ level of use~ This level is about equal to 0.6 pound~ of peroxide oil solution which i~ not explosi~e and can be burned safely.
The following example~ illustrate the manufacture of the present invention and its effectivenes~ in s~opping image diffusion.
The peroxide containing microcapsules used in the following examples were prepared as follows~
A batch o~ peroxide containing capsules was prepared by incorporating 5 grams of commercial peroxide into a dioctyl phthalate oil phase which is made from ~2~
Lupersol PDV (made by ~ucidol, Pennwalt). The total solution amounted to 50 grams. After heating to 60C the oil phase was added to a Waring blender, which contained a ~' water phase at 60~C already stirring at full power. The water phase contained 26.g grams of a 17~1% Isobam solution whose pH was adjus~ed to 4.0 9 38~3 grams of distilled wa~er, ~5 grams of a 10~ a~ueous gum arabic solution, ~.6 grams of dissolved urea and 0.8 grams of resorcinol. After the dispersion of the oil phase averaged a~.out 5 microns, the power was reduced to about 40 volts and 17 milliliters of 37% formaldehyde solution was added. The combined solutions were mixed at 40 volts and 60C for two more hours. Then a solution of 0,6 grams of ammonium sulfate and 1~.1 grams of water was added and mixed for fifteen additional minutes~ The mix~ure was transferred to a beaker and urther mixed at 60C for one hour~ The pH was adjusted to 7~0 by drop-wise addition o~
a 19% sodium hydroxide solution, and the capsules were reserved for further use.
The photosensitive microcapsules used in the following examples were prepared as follows:
A batch o photosensitive capsules was prepared under darkroom conditions in the same way as the batch of peroxide capsules with two exceptions. The ingredients were doubled in amount and the oil phase compris~d 100 grams of trimethylolpropenetriacrylate, 6 grams of Copikem*
IV (a product of Hilton-~avis Co.), 5 grams of benzoin methyl ether, and 2 grams of Michler's ketone. The final pH was adjusted to 9.0 and 5.6 grams of sodium bisulfite was added and dissolved. The capsules were placed in foil wrapped bottles to prevent premature exposure.
*trademarks `'~ 2 Com~rison ~x_m~e~
A portion of the photosensitive capsule ba~ch 2 was diluted with an equal weight of a 10% sodium o~ gum "
arabic and then mixed well. Next the mixture was poured across the coa~ed side of a sheet of ~ead Transrite impact paper under darkroom conditions. The wet mix~ure was drawn in the machine direction by using a number 10 Mayer bar. The coating was dried in a circulating air oven for 2 minutes at 90C.
Two strips of the dried coa~ed surface were cooled, aged one hour in darkroom conditions and then each exposQd imagewise to a Stouffer transparent sensitivity guide, which is a step wedge gray scale. The two strips were covered by Gilclear and then developed by running them through a laboratoEy super calender se~ at ~0 pounds gauge~ which is approximately equivalent to 600 pounds per linear inch of face contact. One of the developed sheets was placed in ~he 90C oven for 5 minutes. Thi~ produced a gray scale on each sample. The samples were placed in a heavy gray envelope to age. The effect of aging on the 2~ image density lthe last gray scale step) is shown in Table 1 below.
Exam~le 1 The coating composition was prepar2d by mixing 10 ~5 grams of peroxide capsules with 90 grams of photosensitive capsules ~nd 100 grams of a 10% solution of gum arabi~.
TnP pH was adjusted to 7Ø
This composition was used to coat paper and prepare exposed and developed samples as in the Comparison Example. The two resulting samples were placed in the same envelope as those from the Comparison. The effect of aging on image density is shown in Table lo ~ 13 -A coating composikion was prepared by mixing ~0 grams of peroxide capsules with 80 grams of photosensi~ive capsules and 100 grams of a 10~ .~olu~ion of gum arabic.
~he pH was adjusted to 7O0~ The procedure was o~herwise the same as in Example 1~ The results ~re shswn in Table 1.
Table 1 shows the results o these tests measured by the last gray scale s~ep of ~he sample i~ages before vi~ible gray scale change.
Last Gray Scale Step 15 min. after 60 days after Example _magin~ Aqin~ Develo~ment Development CompariSon 26C 26C g 7 Comparison 26C 5 min. at 90C~ 8 7 then cooled to 1 2SC 5 min. at 90C, 9 g then cooled to 2 2~C ~6C g 2 26C S min. at 90C 9 9 then cooled to These results clearly indicate that the incorporation of peroxide capsules into the coating provides a precise and stable imagP over a long period of time. Although no tests were run, it is believed that improved smudge and solvent resistance and scuff proofness will also result. Additional testing did c~nfirm that the organic peroxide remained ac~ive and that a very large fraction continued to be present in both the water-suspended encapsula~ion and on the dried paper~
prepared as in examples ~ and 5 for at least several months.
The foregoing descriptions are inteneded to be illustrative. They are not intended to define the scope Of the invention, which i5 limi~ed only by the claims that foll~w.
solubility in water, solubility in the inert carrier oil (which itself should be compatible with the oil phase in the photosensitive composition~s capsuiès) a relatively low hydrolysis rate in water phases having a pH between 3.5 and 9.5 for up to two hours at 40 to 50C, ease of encapsulation, and other considerations with respect to encapsulation. It is important that the encapsulated curing agent have an adequate shelf life.
~referred curing agents are free radical generators such as thermal initiators, which upon reacting with the photosensitive composition cause it to polymerize or crosslink. By exposing the coating composition to actinic radiation, and rupturing the capsules in the presence of a developer material, the chromogenic material and the developer react to produce color in the form of an in~age and the curing agent reacts with the photosensitive composition and ~ardens it, thereby preventing image diffusion. In the case of certain curing agents, lt may be desirable to heat the image to accelera-te the cure. A
curing agent is preferably selected which is relatively inactive at room temperature Ifor good shelf life) and which is readily activated by heating to tempera-tures in excess of room temperature.
A particularly useful class of thermal initiators reactive with ethylenically unsaturated compounds are organic peroxides. Suitable peroxides include diacyl peroxides, ketone peroxides, peroxydicarbonates, alkyl peroxides, alkyl hydroperoxides and sulfonyl peroxides.
Also useful as thermal initiators are bisazides, perborates and diazo compounds.
`,.
~2~ 35 Carrier oil~ conventionally use~ in forming pressure-sensi~ive microcapsules can be used in the preserlt invention provided they are essentially ~nert to the curing agent. Deodorized kero~ense, alkylated 5 biphenyls and alkylated ph~chalates are examples,.
The encapsulation proce~s s:hosen mu~t give a high yield of thermal initiator retained over extended periods of storage, wheSher in water dispersions or after being applied to a subs~rate~ Also, the temperature during manufacture and storage mu~t be maintained below levels tha~ would cause rapid deeomposition of ~he ~hermal initiator~ For this reason, ini~iators which are no~
activated below about 25C are preferably used~
In some situations, peroxides can pre ent a fir~
lS hazard~ Th~s problem can be avoided by limi~ing the amount used~ Preferably, the amount of peroxide used should equal abou~ 0.1 ~o 1.0 percent of ~he weight of photQsensitive composition used. Thus, if three pounds of photosensitive composi~ion ~apsules are used fOE 3, 300 square feet of ~ubstrate paper7 only 0.03 pounds of peroxide would be present at th~ 1~ level of use~ This level is about equal to 0.6 pound~ of peroxide oil solution which i~ not explosi~e and can be burned safely.
The following example~ illustrate the manufacture of the present invention and its effectivenes~ in s~opping image diffusion.
The peroxide containing microcapsules used in the following examples were prepared as follows~
A batch o~ peroxide containing capsules was prepared by incorporating 5 grams of commercial peroxide into a dioctyl phthalate oil phase which is made from ~2~
Lupersol PDV (made by ~ucidol, Pennwalt). The total solution amounted to 50 grams. After heating to 60C the oil phase was added to a Waring blender, which contained a ~' water phase at 60~C already stirring at full power. The water phase contained 26.g grams of a 17~1% Isobam solution whose pH was adjus~ed to 4.0 9 38~3 grams of distilled wa~er, ~5 grams of a 10~ a~ueous gum arabic solution, ~.6 grams of dissolved urea and 0.8 grams of resorcinol. After the dispersion of the oil phase averaged a~.out 5 microns, the power was reduced to about 40 volts and 17 milliliters of 37% formaldehyde solution was added. The combined solutions were mixed at 40 volts and 60C for two more hours. Then a solution of 0,6 grams of ammonium sulfate and 1~.1 grams of water was added and mixed for fifteen additional minutes~ The mix~ure was transferred to a beaker and urther mixed at 60C for one hour~ The pH was adjusted to 7~0 by drop-wise addition o~
a 19% sodium hydroxide solution, and the capsules were reserved for further use.
The photosensitive microcapsules used in the following examples were prepared as follows:
A batch o photosensitive capsules was prepared under darkroom conditions in the same way as the batch of peroxide capsules with two exceptions. The ingredients were doubled in amount and the oil phase compris~d 100 grams of trimethylolpropenetriacrylate, 6 grams of Copikem*
IV (a product of Hilton-~avis Co.), 5 grams of benzoin methyl ether, and 2 grams of Michler's ketone. The final pH was adjusted to 9.0 and 5.6 grams of sodium bisulfite was added and dissolved. The capsules were placed in foil wrapped bottles to prevent premature exposure.
*trademarks `'~ 2 Com~rison ~x_m~e~
A portion of the photosensitive capsule ba~ch 2 was diluted with an equal weight of a 10% sodium o~ gum "
arabic and then mixed well. Next the mixture was poured across the coa~ed side of a sheet of ~ead Transrite impact paper under darkroom conditions. The wet mix~ure was drawn in the machine direction by using a number 10 Mayer bar. The coating was dried in a circulating air oven for 2 minutes at 90C.
Two strips of the dried coa~ed surface were cooled, aged one hour in darkroom conditions and then each exposQd imagewise to a Stouffer transparent sensitivity guide, which is a step wedge gray scale. The two strips were covered by Gilclear and then developed by running them through a laboratoEy super calender se~ at ~0 pounds gauge~ which is approximately equivalent to 600 pounds per linear inch of face contact. One of the developed sheets was placed in ~he 90C oven for 5 minutes. Thi~ produced a gray scale on each sample. The samples were placed in a heavy gray envelope to age. The effect of aging on the 2~ image density lthe last gray scale step) is shown in Table 1 below.
Exam~le 1 The coating composition was prepar2d by mixing 10 ~5 grams of peroxide capsules with 90 grams of photosensitive capsules ~nd 100 grams of a 10% solution of gum arabi~.
TnP pH was adjusted to 7Ø
This composition was used to coat paper and prepare exposed and developed samples as in the Comparison Example. The two resulting samples were placed in the same envelope as those from the Comparison. The effect of aging on image density is shown in Table lo ~ 13 -A coating composikion was prepared by mixing ~0 grams of peroxide capsules with 80 grams of photosensi~ive capsules and 100 grams of a 10~ .~olu~ion of gum arabic.
~he pH was adjusted to 7O0~ The procedure was o~herwise the same as in Example 1~ The results ~re shswn in Table 1.
Table 1 shows the results o these tests measured by the last gray scale s~ep of ~he sample i~ages before vi~ible gray scale change.
Last Gray Scale Step 15 min. after 60 days after Example _magin~ Aqin~ Develo~ment Development CompariSon 26C 26C g 7 Comparison 26C 5 min. at 90C~ 8 7 then cooled to 1 2SC 5 min. at 90C, 9 g then cooled to 2 2~C ~6C g 2 26C S min. at 90C 9 9 then cooled to These results clearly indicate that the incorporation of peroxide capsules into the coating provides a precise and stable imagP over a long period of time. Although no tests were run, it is believed that improved smudge and solvent resistance and scuff proofness will also result. Additional testing did c~nfirm that the organic peroxide remained ac~ive and that a very large fraction continued to be present in both the water-suspended encapsula~ion and on the dried paper~
prepared as in examples ~ and 5 for at least several months.
The foregoing descriptions are inteneded to be illustrative. They are not intended to define the scope Of the invention, which i5 limi~ed only by the claims that foll~w.
Claims (25)
1. A coating composition for use in photoimaging said coating composition comprising a chromogenic material, rupturable microcapsules which contain a photosensitive composition, and a curing agent; said coating composition being characterized in that images are formed by imagewise exposing a coating of said composition to actinic radiation and rupturing said microcapsules in the image areas such that said chromogenic material can react with an associated co-reactive developer material to form a color image and said curing agent reacts with the photosensitive composition following capsule rupture and hardens the same to provide image stability upon aging.
2. The coating composition of claim 1 wherein said curing agent is a free radical generating compound.
3. The coating composition of claim 2 wherein said curing agent is a thermal initiator.
4. The coating composition of claim 3 wherein said thermal initiator is an oganic peroxide.
5. The coating composition of claim 4 wherein the amount of said organic peroxide is less than 1% by weight of the amount of said photosensitive composition.
6. The coating composition of claim 5 wherein said organic peroxide is selected from the group consisting of diacyl peroxides, ketone peroxides, peroxydicarbonates, alkyl peroxides, alkyl hydroperoxides and sulfonyl peroxides.
7. The coating composition of claim 1 wherein said photosensitive composition includes a photopolymerizable ethylenically unsaturated compound.
8. A imaging sheet comprising a substrate, and a coating composition on one surface of said substrate, said composition including a chromogenic material, rupturable microcapsules which contain a photosensitive composition, and a curing agent, said imaging sheet being characterized in that images are formed by imagewise exposing said substrate to actinic radiation and rupturing said microcapsules in the image areas such that said chromogenic material reacts with a co-reactive developer material associated with said imaging sheet, and said curing agent reacts with the photosensitive composition released from said capsules to improve image stability upon aging.
9. The imaging sheet of claim 8 wherein said curing agent is a free radical generator.
10. The imaging sheet of claim 9 wherein said curing agent is a thermal initiator.
11. The imaging sheet of claim 10 wherein said thermal initiator is an organic peroxide.
12. The imaging sheet of claim 11 wherein the amount of said organic peroxide is less than 1% by weight of the amount of said photosensitive composition.
13. The imaging sheet of claim 12 wherein said organic peroxide is selected from the group consisting of diacyl peroxides, ketone proxides, peroxydicarbonates, alkyl peroxides, alkyl hydroperoxides and sulfonyl peroxides.
14. The imaging sheet of claim 8 wherein said photosensitive composition includes a photopolymerizable ethylenically unsaturated compound.
15. The imaging sheet of claim 8 wherein said developer material is present on the same surface of said substrate as said coating composition.
16. The imaging sheet of claim 8 wherein said developer is present on a separate sheet.
17. The coating composition of Claim 1 wherein said photosensitive composition is photohardenable or photosoftenable and said curing agent is an organic peroxide.
18. The coating composition of Claim 17 wherein said thermal initiator is present in said rupturable micro-capsules with said photosensitive composition.
19. The coating composition of Claim 17 wherein said thermal initiator is encapsulated in rupturable microcapsules having discrete capsule walls which are separate and distinct from said rupturable microcapsules containing said photosensitive composition.
20. The coating composition of Claim 1 wherein said curing agent is a thermal initiator, said photosensitive composition includes a photopolymerizable ethylenically unsaturated compound and said rupturable microcapsules have discrete capsule walls.
21. The imaging sheet of Claim 8 wherein said photo-sensitive composition is photohardenable or photosoftenable and said curing agent is an organic peroxide.
22. The imaging sheet of Claim 21 wherein said thermal initiator is present in said rupturable microcapsules containing said photosensitive composition.
23. The imaging sheet of Claim 21 wherein said thermal initiator is present in rupturable microcapsules having discrete capsule walls which are separate and distinct from said rupturable microcapsules containing said photo-sensitive composition.
24. The imaging sheet of Claim 8 wherein said curing agent is a thermal initiator, said photosensitive composition includes a photopolymerizable ethylenically un-saturated compound and said rupturable microcapsules have discrete capsule walls.
25. An imaging system comprising first and second substrates, said first substrate carrying a coating composition including a chromogenic material, rupturable microcapsules which contain a photohardenable or photosoftenable photosensitive composition, and a thermal initiator, said second substrate carrying a developer material which reacts with said chromogenic material to form a color image, said imaging system being characterized in that images are formed by imagewise exposing said first substrate to actinic radiation and assembling said first substrate and said second substrate with said surfaces carrying said microcapsules and said developer in contact, and rupturing said microcapsules in the image areas such that said chromogenic material reacts with said developer to form a color image and said thermal initiator reacts with said photosensitive composition released from said capsules to improve image stability upon aging.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US45874983A | 1983-01-17 | 1983-01-17 | |
| US458,749 | 1983-01-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1216455A true CA1216455A (en) | 1987-01-13 |
Family
ID=23821946
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000445389A Expired CA1216455A (en) | 1983-01-17 | 1984-01-16 | Imaging system |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS59137944A (en) |
| CA (1) | CA1216455A (en) |
| DE (1) | DE3401443A1 (en) |
| GB (1) | GB2133899B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5223371A (en) * | 1991-05-23 | 1993-06-29 | Brother Kogyo Kabushiki Kaisha | Thermal developing type photosensitive pressure sensitive image recording medium |
Families Citing this family (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62148956A (en) * | 1985-12-23 | 1987-07-02 | Fuji Photo Film Co Ltd | Image recorder |
| US4701397A (en) * | 1986-02-26 | 1987-10-20 | The Mead Corporation | Method for forming images on plain paper and an imaging sheet useful therein |
| JPH0623846B2 (en) * | 1986-03-11 | 1994-03-30 | 富士写真フイルム株式会社 | Image forming method |
| JPH0623847B2 (en) * | 1986-03-11 | 1994-03-30 | 富士写真フイルム株式会社 | Transfer image forming method |
| JPS62232638A (en) * | 1986-04-02 | 1987-10-13 | Brother Ind Ltd | Photosensitive pressure-sensitive recording sheet |
| DE3617499A1 (en) * | 1986-05-24 | 1987-11-26 | Hoechst Ag | LIGHT SENSITIVE MIXTURE AND LIGHT SENSITIVE RECORDING MATERIAL MADE THEREOF |
| JPS63110450A (en) * | 1986-10-29 | 1988-05-14 | Brother Ind Ltd | Image forming method |
| US4905036A (en) * | 1986-10-29 | 1990-02-27 | Brother Kogyo Kabushiki Kaisha | Image forming process and system, including heating step or device for increased density of images |
| JPH0610367Y2 (en) * | 1987-04-06 | 1994-03-16 | ブラザー工業株式会社 | Image recorder |
| JPS63193150A (en) * | 1987-02-06 | 1988-08-10 | Seiko Instr & Electronics Ltd | Recorder |
| JPS63218942A (en) * | 1987-03-06 | 1988-09-12 | Fuji Photo Film Co Ltd | Image receiving material and image forming method |
| US4885603A (en) * | 1987-04-02 | 1989-12-05 | Brother Kogyo Kabushiki Kaisha | Image recording apparatus for producing glossy image medium |
| JPS63157746U (en) * | 1987-04-02 | 1988-10-17 | ||
| JPS63200839U (en) * | 1987-06-12 | 1988-12-23 | ||
| JPS6452144A (en) * | 1987-08-24 | 1989-02-28 | Sharp Kk | Image forming process |
| KR890005578A (en) * | 1987-09-15 | 1989-05-15 | 로레인 제이.프란시스 | Receiver sheet containing thermal initiator |
| JPH01140158A (en) * | 1987-11-27 | 1989-06-01 | Fuji Photo Film Co Ltd | Image recorder |
| US5185226A (en) * | 1988-03-23 | 1993-02-09 | Olin Corporation | Electrostatic method for multicolor imaging from a single toner bath comprising double-encapsulated toner particles |
| US5015549A (en) * | 1988-03-23 | 1991-05-14 | Olin Corporation | Composition and electrophotographic use of microcapsular photoactive toner particles |
| US4908301A (en) * | 1988-03-23 | 1990-03-13 | Olin Corporation | Color-self-developing, microcapsular toner particles |
| US5064736A (en) * | 1988-03-23 | 1991-11-12 | Olin Corporation | Electrostatic method for multicolor imaging from a single toner bath |
| US4869981A (en) * | 1988-03-23 | 1989-09-26 | Olin Corporation | Electrostatic method for multicolor imaging from a single toner bath |
| EP0420855B1 (en) * | 1988-03-23 | 1995-04-12 | Olin Corporation | Electrostatic method for multicolor imaging from a single toner bath |
| US6445409B1 (en) | 1997-05-14 | 2002-09-03 | Hitachi Denshi Kabushiki Kaisha | Method of distinguishing a moving object and apparatus of tracking and monitoring a moving object |
| EP0878965A3 (en) | 1997-05-14 | 2000-01-12 | Hitachi Denshi Kabushiki Kaisha | Method for tracking entering object and apparatus for tracking and monitoring entering object |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1001832A (en) * | 1961-01-09 | 1965-08-18 | Du Pont | Improvements relating to image reproduction |
| GB1058798A (en) * | 1963-01-24 | 1967-02-15 | Du Pont | Photopolymerisable elements |
| US3418118A (en) * | 1965-06-03 | 1968-12-24 | Du Pont | Photographic processes and products |
| US3579339A (en) * | 1967-05-23 | 1971-05-18 | Du Pont | Photopolymerizable dispersions and elements containing nonmigratory photoreducible dyes |
| US3892569A (en) * | 1972-12-04 | 1975-07-01 | Gen Film Dev Corp | Photosensitive sheets comprising organic dyes and sensitizers |
| FR2264307B1 (en) * | 1974-03-15 | 1976-12-17 | Cellophane Sa | |
| US4440846A (en) * | 1981-11-12 | 1984-04-03 | Mead Corporation | Photocopy sheet employing encapsulated radiation sensitive composition and imaging process |
-
1984
- 1984-01-16 CA CA000445389A patent/CA1216455A/en not_active Expired
- 1984-01-17 JP JP623684A patent/JPS59137944A/en active Pending
- 1984-01-17 GB GB08401212A patent/GB2133899B/en not_active Expired
- 1984-01-17 DE DE19843401443 patent/DE3401443A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5223371A (en) * | 1991-05-23 | 1993-06-29 | Brother Kogyo Kabushiki Kaisha | Thermal developing type photosensitive pressure sensitive image recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59137944A (en) | 1984-08-08 |
| DE3401443A1 (en) | 1984-07-19 |
| GB8401212D0 (en) | 1984-02-22 |
| GB2133899A (en) | 1984-08-01 |
| GB2133899B (en) | 1986-02-12 |
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