Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Method of use – kit – or combined with marking instrument or...
Reexamination Certificate
2000-03-30
2001-11-06
Hess, Bruce (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Method of use, kit, or combined with marking instrument or...
C503S214000
Reexamination Certificate
active
06313066
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-094207, filed Mar. 31, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an image forming material that can be formed into an image by electro-photography, thermal transfer recording, writing tools or printing, and that can be decolored by control of thermal hysteresis or by contact with a solvent.
With the recent progress of office automation, the amounts of various pieces of information are significantly increasing, and information output is increasing accordingly. Information output is represented by display output and hard copy output from printers to paper sheets. However, display output requires a large-scale circuit board in a display unit and hence has problems in portability and cost. Hard copy output uses a large amount of paper as a recording medium when the information amount increases, leading to problems about the protection of resources. In addition, in order to recycle paper sheets on which images are printed with a printer or a copier, it is necessary to use a large amount of bleaching agent and water, which brings about a rise in recycling cost. Thus, it is proposed to reduce the consumption of paper sheets substantially by printing an image on a paper sheet using a decolorable image forming material, decoloring the formed image to return the paper sheet to a blank sheet, reusing the blank sheet, and recycling the sheet at the time when damage of the sheet becomes serious so that the sheet cannot be reused.
Recently, rewritable paper has been proposed in order to reuse hard copy paper sheets. However, this rewritable paper is applicable only to thermal recording and is not recyclable because it is made of special paper, although it is reusable.
Heretofore, an image forming material that can be decolored by heating has been proposed in, for example, Published Unexamined Japanese Patent Application No. 7-81236. The image forming material includes a color former such as a leuco dye, a developer, and an organophosphoric compound having decoloring ability. When such an image forming material is used, however, decoloration is insufficient and, as a result, a paper sheet is hard to return to the blank state.
We have been developing a decolorable image forming material in which a color former, a developer and a decolorant having high affinity with the developer are dispersed in a binder resin. Now, it becomes possible to attain an excellent decolored state in various material systems by selecting an appropriate decolorant. However, a complete decolored state is not always obtained in all material systems. Thus, it has been recognized that components of the decolorable image forming material can be desirably selected from a wide variety of materials.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming material, containing no decolorant, that can form a clear image and that the image thereof can be decolored well.
According to an aspect of the present invention, there is provided a decolorable material comprising a color former, a developer and a binder resin, wherein the binder resin has a property that it is compatible with the color former when the material is in contact with a solvent and that it keeps the compatible state when the solvent is removed.
According to another aspect of the present invention, there is provided a decolorable material comprising a color former, a developer and a binder resin, wherein the binder resin has a property that it shifts an equilibrium between the color former and the developer to a non-developed side when the temperature of the material is raised and that it keeps the state shifted to the non-developed side when the temperature of the material is lowered.
According to still another aspect of the present invention, there is provided a paper medium comprising a paper sheet and a decolorable material applied to the paper sheet and comprising a color-former, a developer and a binder resin, wherein the binder resin has a property that it shifts an equilibrium between the color former and the developer to a non-developed side when the temperature of the material is raised and that it keeps the state shifted to the non-developed side when the temperature of the material is lowered.
According to yet another aspect of the present invention, there is provided a decoloring method of an image using a material comprising a color former, a developer and a binder resin, comprising steps of heating the image forming material so that the binder resin adsorbs the color former when the temperature of the material is raised, thereby shifting an equilibrium between the color former and the developer to a non-developed side, and keeping the state shifted to the non-developed side when the temperature of the material is lowered.
According to yet another aspect of the present invention, there is provided a decoloring method of an image using a material comprising a color former, a developer and a binder resin, which is applied to a paper sheet, comprising steps of heating the paper sheet so that the binder resin adsorbs the color former and a cellulose component of the paper sheet adsorbs the developer when the temperature of the paper sheet is raised, thereby shifting an equilibrium between the color former and the developer to a non-developed side, and keeping the state shifted to the non-developed side when the temperature of the paper sheet is lowered.
According to yet another aspect of the present invention, there is provided a decoloring method of an image using a material comprising a color former, a developer and a binder resin, which is applied to a paper sheet, comprising steps of bringing the image forming material on the paper sheet into contact with a solvent, thereby making the binder resin and the color former into a compatible state and keeping the compatible state when the solvent is removed.
In the present invention, the binder resin used is preferably a non-polar resin. In the present invention, a binder resin consisting of a copolymer of a polar monomer and a non-polar monomer may be used. In this case, the copolymer preferably comprises 90% or more by weight of the non-polar monomer.
REFERENCES:
patent: 5407890 (1995-04-01), Ishikawa
patent: 5663115 (1997-09-01), Naito et al.
patent: 5849651 (1998-12-01), Takayama et al.
patent: 5922115 (1999-07-01), Sano et al.
patent: 0 980 028 (2000-02-01), None
patent: 0 987 123 (2000-03-01), None
patent: 58-111873 (1983-07-01), None
patent: 01-138275 (1989-05-01), None
patent: 01-138274 (1989-05-01), None
patent: 07-025167 (1995-01-01), None
Hess Bruce
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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