Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Having nonchromogenic liquid spread-control or...
Reexamination Certificate
2001-10-03
2003-11-04
Hess, B. Hamilton (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Having nonchromogenic liquid spread-control or...
C503S208000, C503S216000
Reexamination Certificate
active
06642175
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat-sensitive recording material, and in particular to a heat-sensitive recording material capable of forming high-density color images with little background fogging and having good image preservability.
2. Description of the Related Art
Heat-sensitive recording materials are widely used in the art because they are relatively inexpensive and capable of being processed in compact recording appliances not requiring specific maintenance. In order to increase the density of the color images to be formed on such heat-sensitive recording materials and to improve the image preservability of the materials, various studies are now being made relating to electron-donating leuco-dyes and electron-receiving compounds and to the layer constitution of heat-sensitive recording materials.
2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A, referred to as “BPA”) has been widely used as an electron-receiving compound with respect to electron-donating leuco-dyes used in such heat-sensitive recording materials. However, a heat-sensitive recording material having satisfactory sensitivity, ability to prevent background fogging, and good image preservability has not been obtained.
Japanese Patent Application Publication (JP-B) No. 2-25354 discloses a heat-sensitive recording paper in which N-(4-hydroxyphenyl)-p-toluenesulfonamide is used as an electron-receiving compound. However, with the advancement in recent years of high-speed thermal head printers, even such heat-sensitive recording papers are unsatisfactory in terms of sensitivity, ability to prevent background fogging, and also in terms of thermal head matching properties such as adhesion of contaminants to the thermal heads and abrading the thermal heads.
In addition, heat-sensitive recording materials generally have weak surface strength and inferior printability which gives rise to problems such as peeling of the paper during offset printing. In order to avoid such problems, it is possible to increase the amount of adhesive included in the heat-sensitive color-forming layer. However, increasing the amount of adhesive is problematic in that the color density of the heat-sensitive recording material is lowered. Thus, in order to solve these problems, there has been a strong demand for heat-sensitive recording materials that can ensure high color density and have good printability.
Further, inkjet printers have become widespread in offices as means for outputting from personal computers. Respective recording surfaces of the inkjet recording materials and heat-sensitive recording materials are often put together. However, conventional heat-sensitive recording materials are not satisfactorily resistant to ink for inkjet printers. Therefore, when the recording surface of the heat-sensitive recording material contacts the recording surface of the inkjet recording material, there has been the problem of fogging in the background area of the heat-sensitive recording material and density of the image area being lowered.
Moreover, due to a heightening awareness of the environment in recent years, there has been a demand for heat-sensitive recording materials that utilize supports in which waste pulp (so-called recycled paper) forms the main constituent. However, it has not always been the case that satisfactory heat-sensitive recording materials have been obtained, because background fogging and image preservability become worse as a result of using recycled paper as the support. In particular, when BPA is used as a developer for the recycled paper, background fogging and image preservability deteriorate.
Japanese Patent Application Laid-Open (JP-A) No. 3-140287 discloses a heat-sensitive recording material with which recording sensitivity is improved without attendant background contamination, and that can be applied to ultra-high speed printers as a result. This is due to the use of a recycled paper, wherein a measured value of a base paper by a regular reflection-type surface smoothness sensor under a pressure of 20 kg/cm
2
is no less than 8%. The heat-sensitive recording material disclosed in JP-A No. 3-140287 uses a developer comprising a phenol (such as bisphenol), a sulfone and a hydroxybenzoic acid. However, the image preservability of the heat-sensitive recording material is insufficient.
JP-A No. 4-21486 discloses obtaining a heat-sensitive recording material that has excellent recoloring potential (coloring after preservation), even when recycled paper is used as the support, by using as the developer bis(4-hydroxyphenyl)acetate-n-butyl, 4-hydroxy-4-isopropoxydiphenyl sulfone, 4,4′-thiobis(3-methyl-6-tert-butylphenol) or N,N′-diphenylthiourea. However, resistance to background fogging and image preservability of the heat-sensitive recording material disclosed in JP-A No. 4-21486 are still insufficient.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide a heat-sensitive recording material that ensures increased color density, little background fogging and good image preservability.
It is a second object of the present invention to provide a heat-sensitive recording material having good chemical resistance.
It is a third object of the present invention to provide a heat-sensitive recording material that well matches thermal heads, without leaving contaminants on the thermal heads and without abrading the thermal heads.
It is a fourth object of the present invention to provide a heat-sensitive recording material having good printability.
It is a fifth object of the present invention to provide a heat-sensitive recording material resistant to ink used in inkjet recording systems.
It is a sixth object of the present invention to provide a heat-sensitive recording material which comprises recycled paper of essentially waste pulp as the support and which therefore has the advantage of reducing the burden upon the environment.
It is a seventh object of the present invention to provide a heat-sensitive recording material having sticking resistance.
Specifically, the present invention provides a heat-sensitive recording material comprising support having disposed thereon a heat-sensitive color-forming layer that includes an electron-donating leuco-dye and an electron-receiving compound, wherein the heat-sensitive color-forming layer includes N-(4-hydroxyphenyl)-p-toluenesulfonamide as the electron-receiving compound and includes a sensitizer of 2-benzyloxynaphthalene.
With the heat-sensitive recording material comprising the above structure, color density is raised, there is little background fogging, and preservability of image areas and chemical resistance is excellent in comparison with conventional heat-sensitive recording materials.
The present invention also provides a heat-sensitive recording material comprising a support having disposed thereon a heat-sensitive color-forming layer that includes an electron-donating leuco-dye and an electron-receiving compound, wherein the heat-sensitive color-forming layer includes N-(4-hydroxyphenyl)-p-toluenesulfonamide as the electron-receiving compound and includes an inorganic pigment of calcite-type precipitated calcium carbonate light and/or aluminium hydroxide.
With the heat-sensitive recording material comprising the above structure, color density is raised, there is little background, preservability of image areas is excellent, and compatibility with thermal heads is excellent (contaminants do not adhere to the thermal heads and the thermal heads are not abraded) in comparison with conventional heat-sensitive recording materials.
The present invention also provides a heat-sensitive recording material comprising a support having disposed thereon a heat-sensitive color-forming layer that includes an electron-donating leuco-dye and an electron-receiving compound, wherein the heat-sensitive color-forming layer includes N-(4-hydroxyphenyl)-p-toluenesulfonamide as the electron-receiving compound and includes an adhesive of polyvinyl alcohol having a degree of saponificat
Iwasaki Masayuki
Mitsuo Hirofumi
Watanabe Tsutomu
Fuji Photo Film Co. , Ltd.
Hess B. Hamilton
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