JPS62238551A - Photosensitive recording medium - Google Patents

Abstract

PURPOSE:To obtain the title medium capable of stably controlling image contrast, even if there are dispersion in a light source lamp or developing conditions, etc., by constituting microcapsules from a mixture of a plural kinds of the microcapsules having different optical sensitivities. CONSTITUTION:A large number of microcapsules 32L, 32M, 32H contg. a photosensitive resin and an achromatic coloring matter are mounted on a surface of the title medium. By a part of the microcapsule 32 being exposed partially, the achromatic coloring matter contd. in the microcapsule 32 carries out a coloring reaction with a developer 30, thereby being formed the image contrast in relation to a difference of exposure values. The microcapsules 32L, 32M, 32H are composed of the mixture of the plural kinds of the microcapsules 32 contg. the plural kinds of photosensitive resins having different optical sensitivities in each capsules. Thus, a variable range of the title medium is enlarged, and the contrast of the formed image may be stably controlled, even if in case of scattering in emission value of the light source lamp due to a temp. and an emission place or the developing conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a photosensitive recording medium, and more particularly to a technique for preventing changes in contrast caused by variations in the amount of exposure of microcapsules or variations in development conditions.

Prior Art A large number of microcapsules containing a photosensitive resin and a colorless dye are provided on one side, and when a part of the microcapsules is locally exposed, the colorless dye inside the microcapsules is exposed to a color developer. A type of photosensitive recording medium is known in which a color reaction is caused to form a contrast related to a difference in exposure amount. For example,
This is the photosensitive recording paper described in Japanese Patent No. 8-88739. In such photosensitive recording paper, in order to adjust the contrast between colored areas and non-colored areas, the amount of exposure is changed, or the development processing conditions, such as the pressure during pressure development, are changed. .

Problems to be solved by the invention However, since it is common to use one type of microcapsule in such conventional photosensitive recording media,
Contrast was relatively difficult to adjust. In other words, in the method of changing the exposure amount, it is necessary to change the exposure amount of the photosensitive recording paper within the change area where the color density changes according to the change in the exposure amount, but in the photosensitive characteristics of the microcapsules, the above change It is formed on a photosensitive recording medium because the area is relatively small, and the amount of light emitted by the light source lamp changes relatively large depending on the temperature, and the amount of light emitted per unit area changes relatively large depending on the light emitting location of the light source lamp. Variations in contrast are unavoidable.

In addition, in the method of changing the development processing conditions, for example, uniformly changing the pressure of the pressure roller against the photosensitive recording medium requires a complicated and large mechanical device related to the pressure roller, and the pressure of the pressure roller must be changed minutely. It was difficult.

Means for Solving the Problems The present invention was made against the background of the above circumstances.
The gist of this is that a large number of microcapsules containing a photosensitive resin and a colorless dye are provided on one surface, and a part of the microcapsules is locally exposed to light. In a photosensitive recording medium in which a contrast related to a difference in exposure amount is formed by causing a color-forming reaction with a color developer, the microcapsules each include a plurality of types of photosensitive resins having different photosensitivity. The reason is that it is composed of a mixture of multiple types of microcapsules.

In this manner, the photosensitive recording medium is provided with a plurality of types of microcapsules each containing a plurality of types of photosensitive resins having different photosensitivity, so that the color density characteristics with respect to the exposure amount can be adjusted. Change in stages. In other words, the intermediate region where the color density does not change to that extent even if the exposure amount changes is
It is formed in a changing region where the color density changes as the exposure amount changes. As a result, the region of change is expanded. Therefore, by setting the amount of light emitted by the light source lamp so that the amount of light emitted from the emissive recording medium is in the intermediate range within the above variation range, variations in the amount of light emitted from the light source lamp due to temperature or light emitting location, or changes in development conditions can be avoided. Even if there are variations, the contrast of an image formed on a photosensitive recording medium can be stably adjusted. Furthermore, since there is no need to change the developing conditions, it is possible to eliminate the need for, for example, a complicated and large-sized mechanical device related to the pressure roller, thereby making the device expensive.

Here, the photosensitive recording medium preferably includes a paper support (base layer) and a color developer layer provided on the support, which includes a color developer that develops color by reacting with a colorless dye. It is provided on or within this color developing layer, and contains a photosensitive resin, a polymerization initiator that initiates polymerization of the photosensitive resin when exposed to light, and a colorless dye, and is coated with a suitable outer layer. covered microcapsules. The microcapsules are coated over one surface of the support, and the microcapsules at exposed positions on the photosensitive recording paper are cured by polymerization of the photosensitive resin contained therein. After this, development processing is performed by applying pressure, friction, heating, etc., so that the colorless dye that has oozed out from the uncured microcapsules reacts with the color developer and develops color, forming a colored area on the photosensitive recording paper. A contrast is formed between the non-colored portion and the non-colored portion. This type of photosensitive paper is called a self-coloring type.

As the color developer contained in the color developer layer, for example, various resin acids such as acid clay, inorganic acid, and organic acid, which are well known for carbon-free paper, and acid clay, etc. are used.

The microcapsules contain an appropriate polymerization initiator, photosensitizer, photosensitive resin, colorless dye, and if necessary, a stabilizer, diluent, and solubilizing agent. The photosensitive resin mentioned above may be one commonly used in this field. Examples of these include, for example, cinnamic acid residues, cinnamylidene residues, α, β-unsaturated ketone residues, coumarin residues, α-phenylmaleimide residues, benzophenone residues, stilbene residues, etc. photodimerizable resins with groups, photodegradable resins with photosensitive groups such as diazonium salt residues, quinonediazide residues, azide residues, dithiocarbamate residues, benzoin residues, acryloyl groups, allyl groups, vinyl groups,
A photopolymerized resin having an epoxy group, etc., an ethylenically unsaturated organic compound having at least one terminal ethylene group per molecule, an acrylate prepolymer obtained by partial reaction of pentaerythster and acrylic acid or acrylic ester, Examples include isocyanate modified esters.

Furthermore, as the photopolymerization initiator and photosensitizer, those commonly used in this technical field can be employed. Examples of the former include benzoylanthraquinone, benzophenone, acetophenones, etc., and examples of the latter include anthraquinone, 5-nitrofluorene, etc.

Further, colorless dyes include those well known in carbonless paper, such as colorless compounds having a lactone, lactam, sultone, spiropyran, ester, or amide structure as a skeleton, specifically, triarylumic compounds, Bisphenylmethane compounds, xanthine compounds, thiazine compounds, spiropyran compounds, etc. are used.

The microcapsules used in the photosensitive recording medium are preferably prepared by mixing a plurality of types of microcapsules having different photosensitivity among the photosensitive resins.

This difference in photosensitivity can be achieved by means such as selection of the type or amount of photosensitive resin or photopolymerization initiator in the microcapsules, and/or addition of a photosensitization aid. The difference in photosensitivity between the microcapsules can be appropriately selected depending on the purpose of use, for example, the ability of the light source of the image recording device (for example, the stability of the amount of light emitted).

In addition to photosensitive recording paper in which the photosensitive resin is hardened by exposure as described above, it is also possible to use a photosensitive resin that becomes soft or brittle when exposed to light. As the photosensitive resin, for example, 3-oximino-2-butanone methacrylate, poly4'-alkyl acylo-phenone, etc., which undergo main chain cleavage by light, can be suitably used. A photosensitive recording paper using microcapsules encapsulating such a photosensitive resin has color development characteristics and an opposite yin and yang of an image compared to the above-mentioned photosensitive recording paper.

It is also possible to prepare a capsule sheet and a color developer sheet in which microcapsules and a color developer layer are provided on separate base layers, respectively, and develop the selectively exposed capsule sheet and color developer sheet in a superimposed state. This type of photosensitive recording medium is called a transfer color type.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic diagram of an image recording apparatus that records images using an example of the photosensitive recording medium of the present invention, and is provided with a dark room 12 surrounded by a housing 10.

The original paper 14 on which the image is displayed is placed on a glass plate (not shown), and the photosensitive recording paper 16 is intermittently fed by a plurality of pairs of feeding rows (not shown) on a support stand 18 parallel to the glass plate. After being pressed and developed by a pressure roller 20, it is sent out. Photosensitive recording paper 16
A bar-shaped light source lamp 22 extending along a straight line parallel to and perpendicular to the feeding direction is connected to the image display surface of the base paper 14;
In other words, it is placed at a position that illuminates the entire lower surface. The light source lamp 22 is driven by a drive device (not shown) that can change the amount of light emitted, and the amount of light emitted is set to a predetermined constant value. A filter 24 is disposed in the optical path between the light source lamp 22 and the base paper 14. This filter 24 is a normal filter and may be removed. Then, base paper 14 and photosensitive recording paper 1
An imaging optical device 26 having a convex lens for forming an image displayed on the base paper 14 onto the photosensitive paper 16 is provided between the photosensitive paper 16 and the photosensitive paper 16 . In addition, 27 is a light source lamp 22
This is a reflecting plate with a C-shaped cross section, which is arranged along the .

The light source lamp 22 is driven by power supplied from a drive power source 36, and the drive power source 36 is configured to change the power supplied in accordance with the operation of a contrast adjustment switch 38.

That is, the amount of light from the light source lamp 22 can be changed according to the operation of the contrast adjustment switch 38.

Here, the photosensitive recording paper 16 corresponds to a photosensitive recording medium for recording an image in this embodiment, and is, for example, a photosensitive recording medium similar to that disclosed in JP-A-58-88739. It's paper.

That is, as shown in FIG. 2, the photosensitive recording paper 16 includes a paper support 28 constituting a base layer, a color developer layer 30 provided on the support 28 and containing a color developer, and a color developer layer 30 provided on the support 28 and containing a color developer. A colorless dye that develops a common color by reacting with a colorant and a photosensitive resin that undergoes polymerization and reaction hardening when exposed to light are encapsulated, covered with an appropriate outer skin, and mixed with each other to be coated all over the support 28. It consists of three types of microcapsules 32t-32, 32, coated on. The above photosensitive resin contains a suitable polymerization initiator.

Those microcapsules 32L, 3214.32. 1 includes a photosensitive resin having different photosensitivity at a common wavelength and a colorless dye that develops a common color, and has different color development characteristics with respect to exposure amount. Figure 3 shows
This is the color development property of photosensitive recording paper when only one type of each of the above-mentioned microcapsules 32°, 32, and 4.32H is used. As is clear from the figure, microcapsule 3
A large amount of exposure is required to reaction-cure microcapsules 32. An intermediate exposure amount is sufficient for reactively curing 1.

That is, the microcapsules 32L, 32. , and 32M contain photosensitive resins whose photosensitivity increases in that order. As a result, as shown in FIG. 4, the photosensitive recording paper 16 has intermediate regions B and C in which the color density does not change to a certain degree even if the exposure amount changes, and a change in which the color density changes as the exposure amount changes. It is formed within the region R and has color development characteristics depending on the exposure amount.

In the image recording apparatus, images such as characters, symbols, and figures displayed on the base paper 14 are formed on the photosensitive recording paper 16 and the photosensitive recording paper 16 is exposed to light, thereby forming a latent image. By passing through the pressure roller 20, the microcapsules 32 that are insufficiently exposed to light are crushed depending on the degree of uncuring, and the colorless dye that oozes out reacts with the color developing layer 30 depending on the degree of crushing. Therefore, an image having a density corresponding to the degree of exposure is developed and recorded on the photosensitive recording paper 16. In other words, the light reflected from the white part of the base paper 14 locally exposes the photosensitive recording paper 16, but since the reflected light is not strong from the colored part of the base paper 14, the light corresponding to the colored part of the photosensitive recording paper 16 is There will be insufficient exposure in areas where Therefore, the microcapsules 3 located in the exposed area
2 is cured, and the microcapsules 32 located in the insufficiently exposed portions are crushed because they are not sufficiently cured and develop a black color, for example.

Here, if the output of the light source lamp 22 is set by operating the contrast adjustment switch 3B so that the amount of exposure of the photosensitive recording paper 16 is at point a in FIG. The exposed portions corresponding to the portions are three types of microcapsules 32L, 32. , and 32. Since all of them are cured, they will not be crushed even during the pressure development process. Therefore, an image with clear contrast is developed on the photosensitive recording paper 16. However, if the output of the light source lamp 22 is set by operating the contrast adjustment switch 38 so that the amount of exposure of the photosensitive recording paper 16 is at point b in FIG. Since the microcapsules 32L are not cured, the background of the image developed on the photosensitive recording paper 16 develops color corresponding to the collapse of the microcapsules 32L, and the contrast of the image is lower than in the above case.

In addition, by operating the contrast adjustment switch 38,
If the output of the light source lamp 22 is set so that the amount of exposure of the photosensitive recording paper 16 is 0 point in FIG. 4, the microcapsules 32L and 32M will not harden regardless of the exposure, so The background of the image developed on the microcapsules 32L and 32M develops color corresponding to the collapse of the microcapsules 32L and 32M, and the contrast of the image is further reduced than in the above case.

When an image is recorded in this way, in the image recording apparatus of this embodiment, as shown in FIG.
In the color development characteristics, intermediate regions B and C, in which the color density does not change to that extent even if the exposure amount changes, are formed within the change region R where the color density changes according to the change in the exposure amount. R is enlarged. For this reason,
By setting the amount of light emitted by the light source lamp 22 so that the amount of exposure of the light emitting recording paper 16 is within intermediate regions B and C within the above-mentioned change region R, preferably in the middle, the amount of light emitted by the light source lamp 22 due to temperature or the like can be adjusted. Even if the amount of light emitted or the pressing force of the pressure roller 20 varies, the contrast of the photosensitive recording paper 16 can be stably maintained and changed. In addition, since there is no need to change the developing conditions, for example, the pressure roller 2
This eliminates the need for mechanical devices related to 0 to be complicated and large, resulting in expensive devices.

Although one embodiment of the present invention has been described above, the present invention is also applicable to other aspects.

For example, the photosensitive recording paper 16 in the above embodiment includes:
Three types of microcapsules 32L, 32M, and 32
．． However, two or four or more types of microcapsules may be mixed.

Further, in the photosensitive recording paper 16, three types of microcapsules 32L, 32. ．． 32. The mixing ratio of can be changed as appropriate to obtain an appropriate contrast.

Furthermore, in the above embodiment, the contrast of the image on the photosensitive recording paper 16 was changed by changing the setting of the amount of light emitted by the light source lamp 22, but by changing the filter 24, the contrast of the image on the photosensitive recording paper 16 was changed. It is also possible to change the setting of the amount of light to be used.

Alternatively, instead of changing the light emission amount of the light source lamp 22 or the filter 24, the exposure amount shown in C or b of FIG. A preliminary exposure light source lamp may be provided within the image recording apparatus. For example, if the amount of preliminary exposure provided by the preliminary exposure light source lamp is the value shown in C in FIG. 4, the microcapsules 32. Since the ink is uniformly cured, the contrast can be reduced while maintaining the color density of the background at almost zero.

Note that the above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the configuration of an image recording apparatus using a photosensitive recording medium according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the structure of a photosensitive recording medium used in the apparatus shown in FIG. FIG. 3 is a diagram illustrating the types of microcapsules used in the photosensitive recording medium of FIG. 2 and their coloring characteristics, and FIG. 4 is a diagram showing the coloring characteristics of the photosensitive recording medium of FIG. 2. 16: Photosensitive recording paper (photosensitive recording medium) 32,. 32. ．． 32□: Microcapsule applicant
Brother Industries, Ltd.Figure 1Figure 2

Claims (1)

[Claims] A large number of microcapsules containing a photosensitive resin and a colorless dye are provided on one side, and a part of the microcapsules is locally exposed to light, so that the colorless dye inside the microcapsules is exposed to light. In a photosensitive recording medium in which a contrast related to a difference in exposure amount is formed by a color reaction with a color developer, the microcapsules are composed of a mixture of multiple types of microcapsules having different photosensitivity. A photosensitive recording medium characterized by: