JPH0782201B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an image forming apparatus that forms a selectively cured image by a light-receiving sheet coated with photosensitive microcapsules to form an image. Used in machines, printers, etc.

(B) Conventional Technology A colored image is formed by a light-receiving sheet having a base sheet coated with photosensitive microcapsules containing a photocurable material and a colorless dye, and an image-receiving sheet coated with a developing material for coloring the colorless dye. The method to do is JP-A-58-8
No. 8739. By subjecting the light-receiving sheet to imagewise exposure, a selectively cured image is formed due to the light-curable material contained therein. By stacking the image-receiving sheet on the light-receiving sheet and processing it, the uncured photosensitive microcapsules are cleaved, the colorless dye flows out and color is developed by the developing material, and a colored image is formed on the image-receiving sheet.

(C) Problems to be Solved by the Invention However, when an image is formed using the light receiving sheet and the image receiving sheet as described above, the type of the photocurable material contained in the photosensitive microcapsules has a great influence on the image quality. Was being given. That is, when the gamma (amount of change in density / amount of change in exposure amount) of the photocurable material is large, there is a drawback that an image to be formed is so hard that a minute density change cannot be reproduced.

Further, in the case of forming a color image by a light-receiving sheet in which several kinds of photosensitive microcapsules, which are exposed to light having different wavelengths and develop different colors, are uniformly dispersed, in the case of a photocurable material of each photosensitive microcapsule, Since the gammas are different (it is extremely difficult to select a photo-curable material that has the same gamma for all photosensitive microcapsules), especially in light shades such as human skin tones such as red, blue, and yellow. There is a drawback that a specific color may be colored, and faithful color reproduction cannot be performed.

Therefore, it is an object of the present invention to provide an image forming apparatus capable of forming a high quality image by correcting the gamma of a photosensitive microcapsule.

(D) Means for Solving the Problems In the image forming apparatus of the present invention, a light-receiving sheet in which a substrate sheet is coated with photosensitive microcapsules is conveyed, and the light-receiving sheet side of the conveyed light-receiving sheet is placed on the transparent substrate side. On the supporting base for supporting, the latent image is formed by selectively curing the photosensitive microcapsules by imagewise exposing from the coating layer side of the photosensitive microcapsules of the light receiving sheet, and the image receiving sheet is formed on the light receiving sheet. In an image forming apparatus for forming a color image of a portion corresponding to a latent image by overlapping and pressing, the substrate sheet of the light receiving sheet is a translucent sheet,
Simultaneously with image formation exposure, the support base at the position where the light receiving sheet is imagewise exposed is composed of a light-transmissive member, and from the rear surface of the light transmissive member of the support base, the light-receptive sheet is exposed to the light-transmissive substrate side. An auxiliary exposure light source, which is formed by irradiating the photosensitive microcapsule with light having a photosensitive wavelength, is arranged.

(E) Action In Japanese Patent Laid-Open No. 59-149343, there is disclosed a direction of consuming the oxygen contained in the photosensitive microcapsules by supplementary exposure to the photosensitive wavelength light to correct gamma of the photosensitive microcapsules. Has been done.

In this respect, according to the image forming apparatus of the present invention, since the sheet supporting base at the position where the image forming exposure is performed is formed of the translucent member, the surface of the light receiving sheet, that is, the photosensitive microcapsule layer side Simultaneously with image formation exposure, auxiliary exposure can be easily performed from the back surface side of the light receiving sheet, that is, from the transparent substrate sheet side.

In this case, the photosensitive microcapsules of the light-receiving sheet are exposed from the back side by the auxiliary exposure light source through the sheet support and the transparent substrate sheet, and internal oxygen is consumed to perform gamma correction. At the same time, since the imagewise exposure is performed, the photosensitive microcapsules are selectively and efficiently cured according to the image, and a latent image is thereby formed. In this way, in order to perform the auxiliary exposure at the same time as the image forming exposure, after the oxygen is consumed by the auxiliary exposure, the image forming exposure can be performed in a good gamma state without giving the opportunity for oxygen to permeate into the photosensitive microcapsules again. You can expect a good image.

In particular, since the auxiliary exposure is performed simultaneously with the image forming exposure from the back surface of the light receiving sheet, the light of the auxiliary exposing does not interfere on the optical path of the reflected light for the image forming exposure and disturbs the exposed image, and the reflected light from the document is not disturbed. Since the exposure can be performed faithfully, the image quality is not deteriorated due to the image disturbance.

(F) Embodiment FIG. 1 is a schematic configuration diagram of a copying machine which is an embodiment of the image forming apparatus of the present invention.

A light receiving sheet cassette 2 is provided on the lower right side of the main body 1. The light receiving sheet cassette 2 is detachable and can be replaced. A roll-shaped image receiving sheet is stored in the light receiving sheet cassette 2. The edge portion of the light receiving sheet is pulled out from the light receiving sheet cassette 2, and the cutter 3, the sheet supporting base 4, the pressure roller 5, the conveying rollers 61, 62,
After passing through 63, it is discharged from the lower left of the main body 1 to the outside.
A paper feed tray 7 is arranged in the left center of the main body 1.
An image receiving sheet is stored in the paper feed tray 7, and the paper feed roller 71
Then, the paper is fed to the pressure roller 5, and further discharged to the paper discharge tray 9 via the heat roller 8 and the paper discharge roller 91. The paper discharge tray 9 projects to the left side surface of the main body 1. Further, an optical system device 10 is provided above the main body 1.
The optical system device 10 has a light source, a mirror, and a lens, and has a main body 1
A document placed on the document table on the upper surface is scanned, and the light reflected by the document (imaging exposure light) is applied to the light receiving sheet on the sheet support 10.

The light-receiving sheet is a light-transmissive substrate sheet of polyethylene, polyester or the like coated with photosensitive microcapsules using a binder. This photosensitive microcapsule is a photocurable material that is sensitive to white light,
The resin shell contains a colorless dye that develops black by the developing material coated on the image receiving sheet.

The sheet support base 4 has a light-transmitting belt 42 made of a light-transmitting material such as polyethylene or polyester stretched between rotating rollers 41. Two chargers (not shown) are provided inside the translucent belt 42 to generate corona discharges of opposite polarities, respectively, to adsorb and peel off the light receiving sheet. At the exposure point P on the translucent belt 4, the light receiving sheet is exposed to the reflected light of the document. An auxiliary exposure light source 43 is provided on the inside of the transparent belt 42 (the back surface of the sheet support base 4) and at a position facing the exposure point P (exposure point position).

As the light source lamp 43a of the auxiliary exposure light source 43, for example, a xenon lamp or the like that emits white light having a substantially flat spectral radiant energy distribution in the visible region is used. The light source lamps 43a are arranged in a direction perpendicular to the direction in which the light receiving sheet is pulled out, and uniformly expose the light receiving sheet. The exposure amount of the light source lamp 43a is set to a predetermined amount. That is, the exposure amount is set as follows.

As described above, the photosensitive microcapsule is a resin shell containing a photocurable material and a colorless dye. This resin shell permeates oxygen, and the inside is saturated with oxygen,
The amount of oxygen at that time is the size of the photosensitive microcapsule,
It is almost determined by the type of the photosensitive material. Therefore, the exposure amount required to consume all the oxygen in the resin shell can be obtained, and the exposure amount may be applied to the light receiving sheet. Further, the power of the light lamp 43a and the lighting timing of the light source lamp can be determined from the exposure amount and the drawing speed of the light receiving sheet.

The light source lamp 43a is housed in the frame 43b so that the light does not leak outside. Therefore, it is possible to prevent the image quality from being deteriorated by the light to the lamp 43 reaching the light receiving sheet other than the image forming exposure point position.

Next, the operation will be described.

The optical system device 10 scans the original document and irradiates the exposure point P of the sheet support base 4 with the reflected light of the original document. The light receiving sheet pulled out from the light receiving sheet cassette 2 is a sheet support base 4
Is electrostatically held by a charger (not shown),
At the exposure point P, the document reflected light is exposed from above. At the same time, auxiliary exposure is performed from below by the auxiliary exposure light source 43 through the transparent belt 42 and the base sheet of the light receiving sheet. Oxygen inside the photosensitive microcapsules coated on the light-receiving sheet is consumed by the auxiliary exposure of the auxiliary exposure light source 43, and thereby gamma is corrected. At the same time as this auxiliary exposure, the light-receiving sheet is imagewise exposed by the light reflected by the light source to form a selectively cured image. Since this image forming exposure and the auxiliary exposure are performed at the same time, after the oxygen consumption by the auxiliary exposure, the image forming exposure is performed without giving an opportunity of oxygen permeation into the photosensitive microcapsules, and the selectively cured image with a good gamma state. Is formed.

The light-receiving sheet on which the selectively cured image is formed in this way is peeled off from the sheet support base 4 by a charger (not shown) and moves toward the pressure roller 5. In parallel with this, the image receiving sheet is fed from the sheet feeding cassette 7, superposed on the light receiving sheet, and pressed by the pressure roller 5. By this pressurization, the uncured photosensitive micro-cassette of the light-receiving sheet is cleaved, the contained colorless dye flows out, and color is developed by the developing material of the image-receiving sheet to form a colored image on the image-receiving sheet. After that, both sheets are peeled off, the light receiving sheet is discharged to the outside of the main body 1 by the transport rollers 62 and 63, and the image receiving sheet is discharged to the discharge tray 9 by the discharge roller 91 after being heated by the heat roller. The cutter 3 is for cutting the light receiving sheet to an appropriate length.

The linear pressure of the pressure roller 5 is set to 10 to 35 kg / cm, and the surface temperature of the heat roller 8 is set to about 70 to 150 ° C. so that a substantially good image can be formed depending on the kind of the light receiving sheet. You can Coloring of the colorless dye is promoted by heating by the heat roller 8 (JP-A-61-24495), and when the image-receiving sheet is coated with a thermoplastic polymer pigment in advance, a high-gloss color image is obtained. (Japanese Patent Laid-Open No. 60-259490).

In this way, by using the translucent belt 42 on the sheet support base 4 and providing the auxiliary exposure light source 43 at the rear surface position of the exposure point P, auxiliary exposure can be performed simultaneously with image formation exposure, and a high quality image can be obtained. I was able to. In this example, the photosensitive microcapsules contain a colorless dye that develops black color, but this color may be any other color such as red or blue, and the photo-curable material is also sensitive to white light. However, a material that is sensitive to a specific wavelength light such as infrared rays may be used. When a photo-curable material that is sensitive to light of a specific wavelength is included, an image-wise exposure is performed with the light of that wavelength, and an auxiliary exposure light source that emits light of that wavelength is also used.

FIG. 2 is a diagram showing a schematic structure of a copying machine showing another embodiment of the present invention. In the example of FIG. 1, a photoreceptor sheet coated with one type of photosensitive microcapsules is used, and image formation exposure and auxiliary exposure corresponding thereto are performed. In this example, a plurality of types (3 types) of photosensitive microcapsules are used. By using a light-receiving sheet coated with capsules, image-forming exposure and auxiliary exposure corresponding thereto are performed.
In the figure, the same parts as those in FIG. 1 are represented by the same numbers, and the description thereof will be omitted.

The sheet support base 4'in this example has a plate-shaped light-transmitting plate 42 'made of a light-transmitting material. A light receiving sheet is placed on the transparent plate 42 'and exposed by the reflected light of the original.

A light receiving sheet for full color is stored in the light receiving sheet cassette 2 '. That is, this light receiving sheet is one in which three kinds of photosensitive microcapsules are uniformly dispersed by using a binder on a transparent base sheet. Three
The types of photosensitive microcapsules include a Y-capsule that contains a photo-curable material that is sensitive to B (blue) and a colorless dye that develops a complementary color of Y (yellow), and G (green).
Capsule R that contains a photo-curable material that is sensitive to water and a colorless dye that develops a complementary color M (magenta), R
It is a C capsule containing a photocurable material that is sensitive to (red) and a colorless dye that develops C (cyan), which is a complementary color to the photocurable material. However, the gamma of the photo-curable material contained in each Y, M, C capsule is different. Therefore, when using a light-receiving sheet coated with a plurality of types (three types) of photosensitive microcapsules as described above, not only oxygen consumption is reduced by auxiliary exposure to reduce gamma, but also each photosensitive microcapsule is reduced. All gammas of must be matched. That is, if the respective gammas are different, a specific coloring may occur in a specific density region.

FIG. 3 is a diagram showing the results of copying a gray scale using the light-receiving sheet coated with the Y, M, and C capsules in terms of the relationship between the exposure amount and the density. In the figure, the slope represents gamma, and the gammas of the M capsule and the C capsule are almost the same, but the gamma of the Y capsule is larger than the others. Further, the shift to the left and right represents the sensitivity of each capsule, and the sensitivity of the Y capsule and the M capsule is almost the same, but the sensitivity of the C capsule is lower than the others. Therefore, the grayscale image obtained is C
The density is high, and it is blue and greenish gray. Again 0.8
At the above concentrations, the M concentration is low, and thus the color is more greenish gray. Further, at a density of 0.8 or less, the Y density is low, and thus the color is more bluish gray.

When image formation is performed using a plurality of photosensitive microcapsules in this way, if no correction is made, the entire image is colored in a specific color (blue, green) or a specific density region (density 0.8 A specific coloring (green, blue) may occur in the boundary between the higher density area and the lower density area.

The auxiliary exposure light source 43 'in this example is corrected so that the gammas of the Y, N, and C capsules are matched, and the sensitivity is also corrected to eliminate specific coloring and obtain a high-quality color image.

The auxiliary exposure light source 43 'is a light source lamp 43a'-1, 43a'-2, 43
It has a'-3 and can be used for xenon lamps etc.
The transparent filter, the G transparent filter, and the R transparent filter are interposed. For example, these filters are
b'is the respective light source lamps 43a'-1, 43a'-2, 43a'-
It may be divided so as to accommodate 3 and attached to the frame 43b '. The light source lamps 43a′-1, 43
Each of a'-2 and 43a'-3 is arranged in a direction perpendicular to the conveying direction of the light-receiving sheet as in the above-mentioned example.

The light source lamps 43a'-1, 43a'-2, 43a'-3 are respectively
Irradiate B, G, and R light, respectively, Y capsule, M capsule,
Affects C capsules. Also, the light source lamps 43a'-1, 43
A unique exposure amount is set for each of a'-2 and 43a'-3. That is, the respective exposure amounts are set so that the gamma and the sensitivity of the three types of photosensitive microcapsules are substantially the same.

For example, when using Y, M, and C capsules having the characteristics shown in FIG. 3, first, a reference characteristic curve F is set, and the characteristics of the Y, M, and C capsules are made to substantially match the characteristic curve F. Set the exposure amount to. For example, in the case of the Y capsule, since the gamma is large, the exposure amount for gamma correction is large, but since the sensitivity does not need to be corrected so much, the exposure amount for sensitivity correction can be small. The sum of the exposure amount for this gamma correction and the exposure amount for the sensitivity correction is the light source lamp.
The exposure amount is 43a'-1. Similarly, the light source lamp 43a ′
The exposure amount of -2,43a'-3 can be set.

The image receiving sheet stored in the paper feed cassette 7'has Y,
A developing material for coloring the M and C capsules is coated.

In this way, when image formation is performed from the auxiliary exposure
It was possible to obtain a high-quality color image without causing specific coloring.

In this embodiment, three kinds of light source lamps 43a'-1, 43 are used.
Although a'-2 and 43a'-3 are used, even if two types are used and the characteristics of the photosensitive microcapsules that are not exposed to the light source lamp are made to approximately match the characteristics of other photosensitive microcapsules. good.

(G) Effect of the Invention As described above, according to the image forming apparatus of the present invention, the auxiliary exposure can be performed simultaneously with the image forming exposure by the reflected light from the original from the back side of the light receiving sheet. It is possible to efficiently form a selective cured image by image forming exposure in a good state, and to form a high quality image.

At this time, since the auxiliary exposure is performed from the back surface of the light receiving sheet,
The problem that the light from the auxiliary light source interferes with the image light at the time of imagewise exposure is eliminated, and it is possible to promote obtaining the above-mentioned remarkable high quality image without disturbing the image.

Moreover, when the photosensitive microcapsules consist of three color microcapsules for obtaining a color image,
Not only gamma correction can be performed by the auxiliary exposure light source, but also different sensitivities for each color can be simultaneously corrected to be equal sensitivities, generation of specific coloring and the like can be eliminated, and high-quality and faithful color images can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a copying machine which is an embodiment of an image forming apparatus of the present invention and which forms an image with one type of photosensitive microcapsules. Further, FIG. 2 shows another embodiment 3
FIG. 3 is a schematic configuration diagram of a copying machine that forms an image with photosensitive microcapsules of three types, and FIG. 3 is a diagram showing the relationship between the exposure amount and the density of the three types of photosensitive microcapsules. 4 ... Sheet support, 42 ... Translucent belt, 43 ... Auxiliary exposure light source, 4 '... Sheet support, 42' ... Translucent plate, 43 '... Auxiliary exposure light source.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiharu Tsujimoto 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (56) Reference JP-A-59-149343 (JP, A)

Claims (2)

[Claims] 1. A photoreceptive sheet having a substrate sheet coated with photosensitive microcapsules is conveyed, and the photoreceptive sheet is subjected to photosensitivity on a support table that supports the translucent substrate side of the conveyed photoreceptive sheet. The photosensitive microcapsules are selectively cured by imagewise exposure from the coating layer side of the microcapsules to form a latent image, and the portion corresponding to the latent image is formed by superposing the image-receiving sheet on the light-receiving sheet and applying pressure. In the image forming apparatus for forming a color image of, the substrate sheet of the light receiving sheet is a translucent sheet,
Simultaneously with image formation exposure, the support base at the position where the light receiving sheet is imagewise exposed is composed of a light-transmissive member, and from the rear surface of the light transmissive member of the support base, the light-receptive sheet is exposed to the light-transmissive substrate side. And an auxiliary exposure light source provided by irradiating the photosensitive microcapsule with light having a photosensitive wavelength. 2. The photosensitive microcapsule is a photosensitive microcapsule composed of three colors of yellow, magenta, and cyan, and the auxiliary exposure light source is a photosensitive wavelength light of the photosensitive microcapsule of the above three colors and each color. The image forming apparatus according to claim 1, comprising a plurality of light sources for irradiating the microcapsules with a light amount having a sensitivity according to the microcapsules.