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
1999-09-24
2001-07-17
Hess, Bruce H. (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...
C346S135100, C503S208000, C503S209000
Reexamination Certificate
active
06261992
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reversible thermosensitive recording material, and a recording method therefor, and more particularly to a reversible thermosensitive recording material which utilizes a coloring reaction of an electron donating coloring agent and an electron accepting color developer and in which a colored image is repeatedly formed and erased by appropriately heating and cooling the reversible thermosensitive recording material, and a recording method and apparatus therefor.
2. Discussion of the Related Art
A variety of thermosensitive recording materials are well known in which a colored image can be formed by a coloring reaction when an electron donating coloring agent is brought into contact with an electron accepting color developer while heat or the like is applied thereto.
The thermosensitive recording materials have the following advantages over other conventional recording materials:
(1) color images can be rapidly recorded by a relatively simple apparatus without using such complicated steps as developing and fixing;
(2) color images can be recorded without producing noise and environmental pollution;
(3) various color images, e.g., red, blue, violet and black, can be easily obtained;
(4) image density and background whiteness are high; and
(5) the manufacturing cost is relatively low. Because of these advantages, the above-described thermosensitive recording materials can be widely used, not only as a recording material for price labels in stores, but also as recording materials for copiers, facsimiles, automatic vending machines of tickets, video printers and printers for computers and measuring instruments.
However, the coloring reaction of these thermosensitive recording materials is irreversible and accordingly these recording materials cannot be repeatedly used.
Several thermosensitive recording materials which can reversibly form and erase an image have been proposed. For example, they are as follows:
(1) a thermosensitive recording material which includes gallic acid in combination with phloroglucinol serving as coloring developers (Japanese Laid-Open Patent Publication No. 60-193691);
(2) a thermosensitive recording material which includes phenolphthalein or Thymolphthalein serving as a coloring developer (Japanese Laid-Open Patent Publication No. 61-237684);
(3) a thermosensitive recording material which includes an uniform solid solution of a coloring agent, a coloring developer and a carboxylic acid ester (Japanese Laid-Open Patent Publications No. 62-138556, 62-138568 and 62-140881);
(4) a thermosensitive recording material which includes an ascorbic acid derivative serving as a coloring developer (Japanese Laid-Open Patent Publication No. 63-173684); and
(5) a thermosensitive recording material which includes bis(hydroxyphenyl)acetic acid or a higher aliphatic amine salt of gallic acid serving as a coloring developer (Japanese Laid-Open Patent Publications Nos. 2-188293 and 2-188294).
Some of the present inventors, jointly with others, have proposed a reversible thermosensitive coloring composition which includes a coloring agent such as a leuco dye and a color developer such as an organic phosphate compound, an aliphatic carboxylic acid compound or a phenolic compound each of which has a long-chain aliphatic hydrocarbon group, and a reversible thermosensitive recording material using the coloring composition (Japanese Laid-Open Patent Publication No. 5-124360). The reversible thermosensitive recording material can stably repeat image formation and image erasure by being appropriately heated and cooled, and the image-recorded state or the image-erased state can be stably maintained at room temperature. In addition, Japanese Laid-Open Patent Publication No. 6-210954 has disclosed a reversible thermosensitive recording material which includes a specified phenolic compound having a long-chain aliphatic hydrocarbon group serving as a color developer.
Japanese Laid-Open Patent Publications Nos. 7-52542, 7-68933, 8-132735, 8-310128, 9-272262, 9-270563, 9-300817 and 9-300820 have disclosed techniques in which quick erasability can be achieved by using a specified erasure promoter. However, the techniques have drawbacks in that the erasing properties are not satisfactory.
Because of these reasons, a need exists for a reversible thermosensitive recording material which has quick erasability, as well as good coloring properties and good preservation properties.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a reversible thermosensitive recording material which has quick erasability.
Another object of the present invention is to provide a dreversible thermosensitive recording material in which recorded images have good preservation property.
The invention also embraces a recording method and apparatus using such a reversible thermosensitive recording material.
To achieve such objects, the present invention contemplates the provision of a reversible thermosensitive recording material which includes a recording layer including a reversible thermosensitive coloring composition including an electron donating coloring agent and an electron accepting color developer and in which an image is reversibly formed and erased by appropriately heating and cooling the recording layer, wherein the recording layer further includes an erasure promoter having one or more secondary amide group having a formula selected from the group consisting of the following formula (1), (2) and (3):
wherein each of R1-R5 independently represents a saturated or unsaturated hydrocarbon group which is optionally substituted, and wherein R1 and R2 are optionally combined to form a ring which may include a nitrogen atom, an oxygen atom or a sulfur atom.
At this point, “a secondary amide group” means an amide group in which the nitrogen atom is substituted by two substituents.
The erasure promoter preferably includes an alkyl chain having 6 or more carbon atoms and the secondary amide group.
The erasure promoter preferably includes a group having an association ability (a group capable of forming an associated state). The group having an association ability preferably has a formula selected from the group consisting of the following groups (4), (5) and (6):
The erasure promoter preferably includes two or more secondary amide groups having formula (1), (2) or (3).
The compound having two or more secondary amide groups having formula (1), (2) or (3) preferably has the following formula (4′), (5′) or (6′).
wherein each of R6′-R18′ independently represents a hydrocarbon group which is optionally substituted and which may be saturated or unsaturated, and wherein R7′ and R8′, and R9′ and R10′ are independently and optionally combined to form a ring which may include one or more of a nitrogen atom, an oxygen atom and a sulfur atom.
In another aspect of the present invention, a reversible thermal image recording method for the reversible thermosensitive recording material is provided, including the steps of recording by imagewise heating the recording layer of the recording material of the present invention at a temperature not lower than an image forming temperature to form a colored image in the recording material and erasing by heating the colored image at a temperature lower than the image forming temperature and not lower than an image erasing temperature.
In yet another aspect of the present invention, a reversible thermal image recording apparatus for the reversible thermosensitive recording material is provided which includes an image forming device which imagewise heats the recording layer of the recording material at a temperature not lower than an image forming temperature to form an image in the recording layer when the recording layer is cooled, and an image erasing device which heats the recording layer at a temperature lower than the image forming temperature and not lower than an image erasing temperature to erase the image, w
Furuya Hiromi
Kawamura Fumio
Matsui Hiroaki
Shimada Masaru
Tatewaki Tadafumi
Cooper & Dunham LLP
Hess Bruce H.
Ricoh & Company, Ltd.
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