JPS6019136A - Image forming method - Google Patents

Abstract

PURPOSE:To form an image reversibly and to obtain a hard copy by exposing or heating image information to form a pattern on the surface of a substrate holding uniformly a reversibly ionic dissociable substance. CONSTITUTION:Image information is exposed or heated to form a pattern on the surface of a substrate holding uniformly a reversibly ionic dissociable substance such as spiropyrane represented by the formula (where n is integer of 8-30, each of R1 and R2 is H, 1-5C alkoxy, 2-6C alkoxycarbonyl or halogen, and the nitro group bonds to the 6'- or 8'-position). Said compound is vacuum deposited, or a coating material contg. the compound by about 20-50pts.wt. per 100pts.wt. polymer binder is coated to form a uniform film on the surface of the substrate. When the surface of the substrate is patternwise exposed, the undissociated and parts of said compound are made different from each other in the wetting property to a liq., and ink applied is patternwise distributed by the difference. A copy can be obtd. by transferring the distributed ink to paper or the like. The dissociated part can be returned to the undissociated state by irradiating visible light on the whole surface of the substrate after transferring the ink, so the image forming material can be used repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method that utilizes the fact that the liquid wetting properties of a reversibly ionically dissociated substance are reversibly changed by light or heat.

[Prior art]

In recent years, with the diversification of information processing needs on various sides, there has been a desire to develop a reversible and simple image forming method. Image forming methods using optical signals include silver halide photography, diazo photography,
Thermophotographic methods, photoresist methods, and the like are known, but most of these methods are irreversible. Although electrophotography can be used as a reversible type, it has not been put to practical use because the lifespan of a reversible image is short. Therefore, there has been no method for reversibly forming an image based on optical signals and for making a hard copy of the image.

[Purpose of the invention]

An object of the present invention is to provide an image forming method that satisfies the above requirements.

[Structure of the invention]

To summarize the present invention, the present invention is an invention of an image forming method, in which a pattern is formed by pattern exposure or pattern heating of image information on a substrate surface uniformly holding a reversibly ionically dissociated substance. It is characterized by including the step of causing.

The modes of change in substances that exhibit reversible absorption spectrum changes, that is, photochromism, due to light irradiation include (1) heterolytic cleavage (ionic dissociation), +2) homolytic cleavage (radical dissociation, and (3) cis-trans (4) tautomerization. Among these, spiropyrans, triarylmethanes, polymethine dyes,
For substances that undergo heterolytic cleavage, such as indenones, the dipole moment changes significantly before and after the change, and so the wettability with respect to liquid changes significantly. Therefore, an image is formed by pattern exposure or pattern heating of image information on a plate surface uniformly holding these substances, and furthermore, by utilizing the difference in wettability to liquid between colored and uncolored areas, ink transfer is performed. It may also be possible to do this and make a hard copy of the image. As a result of intensive study on this point, we have discovered an unprecedented image forming method. Hereinafter, the image forming method of the present invention will be explained in more detail by taking spiropyrans, which have particularly good properties, as an example.

Spiropyrans are ionically dissociated by light irradiation, and recovered to their nine-element undissociated state by heat or light.

Its reversible dissociation is -for example, 6'-nitro 1°5.
3-) Limethylspiro [indoline-2,2'-benzopyran] is explained as follows.

(Colorless state) (Colored state) That is, when a colorless spiropyran form is irradiated with ultraviolet rays, the C-0 spiro bond is heterolytically cleaved and changes to a merocyanine form, which develops a color.This merocyanine form is irradiated with heat or visible light. After that, it changes to the original spiropyran form and becomes colorless. This change can be repeated several dozen times. Spiropyrans that generally have this property are represented by the general formula (■) below. It was available for use.

(Here, n represents an integer of 8≦n≦30, R1, R2
is a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, and 2 carbon atoms.
~6 alkoxycarbonyl groups or halogen atoms. In addition, the nitro group is bonded to the 6'- or 8'-position.) A glass plate, a plastic plate, a metal plate, or the like was used as the base material for the substrate surface to uniformly hold these compounds. By vacuum-depositing spiropyrans onto a substrate, or by uniformly dissolving them in a polymeric binder solution, applying them to the substrate, and drying, it was possible to create a substrate surface that uniformly held spiropyrans. The polymer binder used in this case is not particularly limited as long as it is soluble in the solvent that dissolves spiropyrans, but examples include polystyrene, polyacrylic ester, polymethacrylic ester, polyvinyl formal, polyvinyl butylene, and polyvinyl butylene. Vinyl acetate, polyvinyl chloride-polyvinyl acetate copolymer, etc. are praised.

By performing pattern exposure on the substrate surface prepared by the above method, the wettability of the undissociated part and the dissociated part to liquid changes to a shape distribution corresponding to the pattern, and absorbent cotton containing water-based ink is used. By rubbing lightly with υ, the aqueous ink adhered to the dissociated area, and the aqueous ink was removed from the unreleased area, making it possible to sufficiently separate the undissociated area from the dissociated area. In addition, by exposing the entire surface of the substrate surface or exposing it to pattern light, and then heat-treating the dissociated and colored parts to return them to an undissociated state, we can improve the wettability of partially modified or more diverse patterns. In this case as well, the aqueous ink could be distributed on the substrate surface in a desired pattern.

In this way, it was possible to transfer the patterned ink onto paper and make copies. In addition, two different tones are available.
It was also possible to form images by multicolor recording using more than one type of ink and a substrate surface having the same or different wettability distribution.

Furthermore, by irradiating the entire surface of the substrate after ink transfer with visible light or heating it, the entire surface can be returned to an undissociated state.
This substrate surface could be used repeatedly.

On the other hand, if oil-based ink is used, the ink is retained only in the undissociated portions, so it is also possible to obtain a pattern that is inverse to that of water-based ink.

When using a spiropyran with n less than 8 in the general formula I, the difference in liquid wettability between the ultraviolet irradiated part and the non-irradiated part is not significant, resulting in a good contrast of 7.
It was not possible to obtain a single copy. Also, n is 30
It is difficult to synthesize anything with a super-large amount. Therefore, 8≦n≦30
It is appropriate to use spiropyrans.

When a polymer binder is used, it is contained in the polymer binder at a ratio of more than 920 parts by weight to less than 50 parts by weight per 100 parts by weight of the polymer binder. Note that 90 parts by weight per 100 parts by weight of the polymer binder is hereinafter expressed as PHR.

When the spiropyran content in the binder was 20 PHR or less, the difference in liquid wettability between the ultraviolet irradiated area and the non-irradiated area was not significant and the object of the present invention could not be achieved. Also,
When the spiropyran content exceeds 5 (I PHR), spiropyran microcrystals form in the binder, making it difficult to produce a uniform substrate surface. Therefore, when the spiropyran content in the binder exceeds 20 PER
5 Q PI (preferably less than R).

〔Example〕

The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 6'-nitro-1-octyl-3,3-dimethylspiro[indoline-2,2'-benzopyran] (11,8
'-Methoxy-6-nitro-1-dodecyl-3゜3-dimethylspiro [indoline-2,2'-benzopyran]
(2), 5-chloro-6'-nitro-1-dodecyl-3
, 3-dimethylspiro[i/dorin-2,2'-benzopyrano] (3), 6'-nitro-1-octadecyl-6
,3-dimethylspiro[indoline-2,2'-benzopyran] (using 41, spiropyran was 4Q PH
A solution containing approximately spiropyran binder solvent j (11 (I?) polystyrene (2
, 5 clauses Benzene (25m1) 2 f2]' (1fJ Polymethyl methacrylate (2,5f)
2 Minoh 5 (31'
(19 mboristyrene (2,5f)benzene (25mA
) Each solution was spun at 2000 rpm using a spinner.
By coating the spiropyran on a glass plate at a rate of 1/2 min and drying it at 60°C for 1 hour, it is possible to produce a substrate surface with spiropyran uniformly held thereon.

Further, even when the spiropyrans (1) to (4) were vacuum-deposited on a glass plate, similar substrate surfaces were obtained.

The surface of these substrates changes from colorless to dark blue when irradiated with ultraviolet rays, and the wettability to pure water also changes significantly, indicating a sufficient change in optical density and wettability. ) Notes 1 (!) Spin coating 0.58 17 Prepared from solution 1 2 f2) 0.8
3 24° 1215 (310,7820y5 # 4 (410,952714# 5 (1) Vacuum deposition 1.65 7 -6 (2) 1
．． 99 12-7 (31t8o 12-8 (4) 2.0415-j) Increase in optical density when irradiated with ultraviolet rays from a 500W ultra-high pressure mercury lamp with UV-D35 filter for 10 seconds from a distance of 5 cIn2) UV-D35; Decreased contact angle of distilled water droplets when irradiated with ultraviolet rays from a 500 W ultra-high pressure mercury lamp with YF filter for 10 seconds from a distance of 3 crn Example 2 A solution was prepared by mixing 10 parts of polystyrene (average degree of polymerization 1600) and tan part of benzene. and 6'-nitro-1-octadecyl-5,3-dimethylspiro[indoline-2
, 2'-bennobi 2F were added under a yellow safety light and completely dissolved.

This solution was spin coated onto a quartz substrate to form a recording medium.

A transparent negative original is placed in close contact with this recording medium, and UV-D 55
When UV rays from a 500W ultra-high pressure mercury lamp equipped with a filter (manufactured by Toshiba Corporation) were irradiated for 10 seconds from a distance of 10 mm from the recording medium, a clear image was obtained in which the irradiated area was colored deep blue.Next, this image When the entire surface of the board is lightly rubbed with absorbent cotton soaked in water-based red ink for recorders (manufactured by Light Ink (R-GHT-NK) Co., Ltd.), the ink will adhere only to the colored areas, and then the ink will be applied to the top of the image board. When the paper was pressed, the ink was transferred to the paper and a positive image was obtained.Next, when a copper block heated to 110℃ was pressed for 10 seconds on the image plate used, the coloring at the bottom of the block became colorless. Then, a colored image was obtained again by the same ultraviolet irradiation as described above. In the transfer of aqueous ink using this image plate, an image of the same quality as that from the substrate surface before reuse was obtained.

Example 3 Polymethyl methacrylate (average degree of polymerization 7.000) 1
0 parts and 100 parts of ethyl acetate to form a solution, 6'
34 parts of -dito-o-1-dodecyl-3,3-dimethylspiro[indoline-2,2'-bennovi2] were added under a yellow safety light and completely dissolved. This solution was spin-coated onto a quartz substrate to form a recording medium. UV-
10. Ultraviolet rays from a SOOW ultra-high pressure mercury lamp equipped with a D55 filter (Toshiba & Co.) are emitted from the recording medium. 10 from the distance of
When irradiated for seconds, the entire surface of the recording medium was colored deep blue.

Next, a transparent negative original is superimposed on this colored recording medium, and an I
KW Tungsten/The visible light of the lamp is transferred from the recording medium to
When irradiated for 10 seconds from a distance of 6n, a negative image was obtained in which the visible light exposed areas turned colorless. Next, the entire surface of the image board is lightly coated with absorbent cotton soaked with water-based green ink for recorders (manufactured by Light Ink Co., Ltd.), so that the ink sticks only to the colored areas, and the paper is pressed onto the ink-covered image board. As a result, the ink was transferred to paper and a negative image was obtained. After removing the ink from the used substrate surface, visible light from a xenon lamp equipped with an ultraviolet cut filter was applied to the substrate surface at a distance of rtm. By irradiating the substrate for 1 minute, the surface of the substrate returned to colorless color and could be reused as in Example 2.

Example 4 A spiropyran content of 4 Q PHR recording medium was prepared in the same manner as in Example 2 using 6'-nitro-1-octadecyl-3,3-dimethylspiro[indoline-2,2'-benzopyran] and polystyrene. After irradiating the entire surface with ultraviolet rays to color it blue, a negative image was obtained by heating any part using a thermal pen to make it colorless. When the entire surface of this image plate was lightly rubbed with absorbent cotton soaked with water-based green ink for recorders (Light Ink Company 2 (J, )), the ink adhered only to the colored areas, and paper was pressed onto the ink-covered image plate. However, the ink was transferred to the paper and a negative image was obtained.

Example 5 5-ditro-6'-ditro-1-dodecyl-3°3-dimethylspiro [indoline-2,. A recording medium having a uniform photosensitive layer with a thickness of 5 μm was prepared by vacuum-depositing 2'-benzopyran on a glass plate. A striped original with 111IIH lines and spaces was placed on top of this, and an ultra-high pressure mercury lamp with an ultraviolet transmission filter was placed at a distance of 31:tn.
Irradiated for 0 seconds. Next, the entire substrate surface was lightly rubbed with absorbent cotton containing red water-based ink to adhere the red water-based ink only to the colored areas, and then paper was pressed to transfer the ink to obtain a red striped image. The ink was removed from the substrate surface after use, and the substrate surface returned to colorless color by irradiating it with visible light from a xenon lamp equipped with an ultraviolet cut filter for 1 minute from a distance of 5 tyn. The same striped pattern original as above was placed on top of this, and after irradiating it with ultraviolet rays to make the blue water-based ink adhere only to the colored areas, the ink was transferred to the same paper as before with the substrate surface rotated 90 degrees from the previous time. As a result, an image with a three-color lattice pattern of red, blue, and violet was obtained, with the intersections of the lattice appearing purple.

Comparative Example 1 Spiropyran of formula I in which the number of carbon atoms in the N-alkyl group is 7 or less, i.e. 6'-nitro1j,5-)dimethylspiro[indoline-2,2'-benzopyran] (5), 6'
-Nitro-1-hebutyl-3,3-dimethylspiro[indoline-2,2'-benzopyran] (6) at 40 P
A solution containing HR was prepared.

Solution number spiropyran binder solvent 5 (5)
(lF) Polymethacrylic Methyl Kawashun (2,5?) Ecal Acetate (25mj+) 6 (6) (1 season) Each solution of polystyrene (z51 and benzene (25al) was applied to a glass plate in the same manner as in Example 1 and dried. A substrate surface that uniformly holds spiropyran was prepared. Also, (5), (
6) was vacuum-deposited to prepare a similar substrate surface. When the surfaces of these substrates were irradiated with ultraviolet rays, as shown in Table 2,
Regarding optical density, although there is a case where a considerable change is observed before and after ultraviolet irradiation (sample number 11.12), in general, the change in wettability is small, so it is difficult to transfer images using water-based ink. could not be done. (
Note that in Table 2, AD and lθ are the same as in Table 1. ) Table 2 Sample number Shi b0in preparation method AD Δθ Remarks 9 (
5) Spin coating 0.75 2.8° Preparation from solution 5 10 (5) Vacuum deposition 0.26 9.0° -u
(6) Spin coating 112 5.4° Preparation from solution 6 12 (6) Vacuum deposition 1.54 11.8° - Comparative example 2 Spiropyran (1) used in the example, f21 at 20PH
The following solutions containing R or 5 g PHR were prepared.

Solution number 0 Binder Solvent 7 (11 (0
，! V polystyrene (2,!M') benzene (25) 8 (tl (1r) polystyrene (22) benzene (
20-9(2+((L5f)
2,5t) Ecal acetate (25tne) 10 (21(
1t) Methyl acetate (22) Epsilene acetate (2rke) Each of these solutions was applied to a glass plate and dried to prepare samples 15, 14, 15, and 16 of the substrate surface holding spiropyran. spiropyran 5
Q On the substrate surface containing PHR, spiropyran precipitated as microcrystals in the binder, so the substrate surface was not uniform. Furthermore, when a uniform substrate surface containing 20 PHR of spiropyran was irradiated with ultraviolet light, a relatively large difference in optical density was obtained before and after irradiation, as shown in Table 3.
Because the difference in wettability to water was small, it was not possible to transfer images using water-based ink.

(In Table 3, jD and lθ are the same as in Table 1.

Table 3 Sample number
5 (11 (20 PHR) 0.46 2.6 - Prepared from solution 7 15 (21 (20 PHR) 0.80 3
．． 2° ・Produced from Solution 9 [Effects of the Invention] As explained above, by using the present invention, it is possible to form image information that can be rewritten only by light irradiation and to make a notebook copy of this image. Furthermore, it is possible to erase the image and use the substrate surface repeatedly, so (1) only the necessary 4 blueprints can be produced from the information and communication terminal by creating an original plate using light energy, or in monochrome or color by ink transfer. (2) It contributes to resource saving of board material for the substrate surface.

Patent applicant: Nippon Telegraph and Telephone Corporation Agent Hiroshi Mototo Same as Akira Inoue

Claims (1)

[Claims] 1. An image characterized by including the step of forming a pattern pattern of image information on a substrate surface uniformly holding a reversibly ionically dissociated substance by pattern exposure or pattern heating. Formation method. λ The substrate has the following general formula I: (where n represents an integer of 8≦n≦60, R1, “2
is a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, and 2 carbon atoms.
~6 alkoxycarbonyl groups or halogen atoms. The image forming method according to claim 1, which is prepared by uniformly vacuum-depositing a compound represented by a nitro group (the nitro group is bonded at the 6'- or 8'-position) onto the substrate. is the following general formula I: (where n represents a product of 8≦n≦30, “1,”
4 represents a hydrogen atom, an alkoxy group having 1 to 5 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a halogen atom. Also, the nitro group is bonded to the 6'- or 8'-position)
A product prepared by uniformly coating a substrate with a compound represented by the formula containing a compound represented by the formula in a polymer binder at a ratio of more than 20 parts by weight to less than 50 parts by weight per 100 parts by weight of the polymer binder and drying. An image forming method according to claim 1.