JPH0719035B2 - Image forming apparatus having image forming exposure apparatus - 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 imagewise exposing a light-receiving sheet by a slit exposure method to form an image.

(B) Conventional Technology A light-receiving sheet coated with a photosensitive microcapsule containing a colorless dye and a photocurable material in a resin shell is subjected to imagewise exposure by reflected light of an original or the like to form a selectively cured image,
JP-A-58-88739 discloses a method of forming an image on an image receiving sheet by superimposing and pressing an image receiving sheet coated with a developing material for developing the colorless dye on the light receiving sheet. . The colorless dyes that develop yellow, magenta, and cyan, and the photo-curable materials that are sensitive to blue, green, and red are contained in individual resin shells, and the three types of photosensitive microcapsules are uniformly dispersed. If the exposed light-receiving sheet is exposed with white image-forming exposure light having color information, a full-color image can be formed with one exposure, and the process can be simplified as compared with the full-color process using the electrophotographic method. is there.

In an image forming apparatus using such a light receiving sheet, a filter is provided in the optical path of the image forming exposure light in order to correct the light curing characteristics such as sensitivity of the light receiving sheet. For example, in a light-receiving sheet coated with three types of photosensitive microcapsules, when the sensitivity of one type of photosensitive microcapsule is lower than that of another type, the light amount of the wavelength region sensitive to the photosensitive microcapsule is changed to another wavelength. If the light quantity of the area light is made relatively large, the three kinds of sensitivities can be apparently matched and a good image can be formed.

(C) Problems to be Solved by the Invention Conventionally, a filter for correcting the light-curing characteristic of an image forming apparatus has been set according to the average light-curing characteristic of the light-receiving sheet. The characteristics are slightly different for each manufacturing lot. Therefore, when an image is actually formed, for example, in the case of a full-color image, specific coloring may occur, and the quality of the formed image cannot be maintained high. Further, even if the same image is formed, the image density may be different due to the difference in the production lot of the light receiving sheet.

According to the present invention, the means for inputting the photo-curing property of the light-receiving sheet and the area for which the filter absorbs or reflects the image-forming exposure light in accordance with the input data are made variable so that the photo-curing property of the light-receiving sheet can be adjusted. It is an object of the present invention to provide an image forming apparatus having an image forming exposure device that enables image forming exposure and does not deteriorate image quality even when using light receiving sheets of different production lots.

(D) Means for Solving the Problems An image forming apparatus having an image forming exposure device of the present invention forms an image by forming image forming exposure light on a light receiving sheet through a lens and a slit. In the device, in the vicinity of the lens, while providing a filter that slightly moves in the direction perpendicular to the slit and absorbs or reflects light in a specific wavelength range of the image forming exposure light, based on the light curing characteristics of the light receiving sheet, And a means for setting a minute movement amount of the filter.

(E) Action In the image forming apparatus having the image forming exposure apparatus of the present invention, in the direction perpendicular to the slit for linearizing the image forming exposure light,
The filter is capable of minute movement, and by minutely moving the filter, the area where the filter reflects or absorbs light of a specific wavelength region of the image forming exposure light changes in minute units, and the light amount also changes in minute units. Therefore, by setting the minute movement amount of the filter according to the light curing characteristic of the light receiving sheet to be input, it is possible to set the light amount according to the light curing characteristic in minute units, and to perform good image formation. You can

(F) Embodiment FIG. 3 is a schematic configuration diagram of a copying machine which is an embodiment of an image forming apparatus having the image forming exposure apparatus of the present invention.

At the lower right portion of the main body 1, there is provided a light receiving sheet cassette 2 for storing a light receiving sheet. This light-receiving sheet is for full color, and includes a Y-capsule containing a photo-curing material sensitive to B (blue) and a colorless dye that develops Y (yellow), a photo-curing material sensitive to G (green) and M. M capsules containing R and a colorless dye that develops (magenta), R
Three types of photosensitive microcapsules, a C capsule containing a photo-curable material sensitive to (red) and a colorless dye that develops C (cyan), are uniformly dispersed and coated on a base sheet such as polyester. .

The end portion of the light receiving sheet is discharged to the lower left portion of the main body 1 via the cutter 3, the sheet support 4, the pressure roller 5, and the transport rollers 61, 62, 63. On the left side of the main body 1, a paper feed cassette 7 for accommodating an image receiving sheet is arranged. The image receiving sheet is fed from the paper feeding cassette 7 to the pressure roller 5, and is ejected to the ejection tray 9 via the heat roller 8. The pressure roller 5 pressurizes the light-receiving sheet and the image-receiving sheet on which the selectively cured image is formed, so that a color image is formed.

A document table 10 for placing a document is provided on the upper surface of the main body 1,
An optical system including a document scanning light source 11, mirrors 12a to 12d, and a lens 13 is arranged below it. The optical system scans the original on the original table 10 and guides the reflected light (image forming exposure light) to the sheet support base 4 through the slit 41, and image-exposes the light receiving sheet on the sheet support base 4.

An auxiliary exposure device 42 for correcting the photo-curing characteristics (mainly gamma) of the light-receiving sheet is provided above the sheet support base 4. The gamma correction of the light receiving sheet is disclosed in JP-A-59-149343, and the auxiliary exposure reduces the amount of oxygen in the photosensitive microcapsules and improves the gamma characteristics. The auxiliary exposure device 42 includes a B light source 42a for irradiating B light, a G light source 42b for irradiating G light, and an R light source 42c for irradiating R light, and corrects gamma of Y capsule, M capsule, and C capsule, respectively. . B, G, R each light source, for example, halogen tungsten lamp B, G, R respectively
R A filter with a filter that transmits each light is used.
Besides, LEDs, EL panels, etc. may be used.

FIG. 1 is a side view of the vicinity of the lens 13 of the optical system.

The lens 13 can be moved in the direction of arrow F or G in the drawing by a moving unit (not shown). Moving the lens in the F direction gives a reduced copy image, and moving it in the G direction gives a magnified copy image. Behind lens 13 (exposure point P
On the side), three types of filters 14, 15, 16 are provided. These filters 14, 15 and 16 are provided in a lens moving unit (not shown) and move together with the moving unit.

The filters 14, 15 and 16 are mainly for correcting the photo-curing characteristics (mainly sensitivity) of the light-receiving sheet, and the formed image can be adjusted according to the user's preference according to the input from the operation panel (not shown). It is also used to add color. FIG. 4 is a diagram showing the characteristics of these filters 14, 15 and 16.
The filter is a Y filter that reflects B light of 400 to 500 nm 1
4, M-filter 15, 600-70 which reflects G light of 500-600nm
The C filter 16 reflects R light of 0 nm. As these filters, for example, dichroic filters in which a glass is multilayer coated are used. These filters 14, 15, 16 are plate-shaped rectangular ones, and the lens 13
Can be covered. The filters 14, 15 and 16 can be moved minutely in the vertical direction (direction perpendicular to the slit 41) and
The area covering 13 can be changed.

The movement of the filter is performed by, for example, a stepping motor. For example, a rack is provided at the rear end of the filter 14, and a pinion that engages with the rack is provided on the stepping motor 14a. The rotation of the stepping motor 14a causes the filter 14 to slightly move in the arrow B or C direction (vertical direction). Similarly, the stepping motors 15a and 16a are connected to the filters 15 and 16 respectively, and the filters 15 and 16 are slightly moved in the arrow B or C direction (vertical direction).

When the filters 14, 15, 16 are moved in the directions of arrow B or C by the stepping motors 14a, 15a, 16a, the area covered by the respective filters, that is, the area ratio for blocking the reflected light of the original is changed. If it is moved in the direction of arrow B, the area ratio becomes smaller, and if it is moved in the direction of arrow C, the area ratio becomes larger. FIG. 5 is a diagram showing the relationship between the light amount and the area ratio where the C filter 16 blocks the light from the light source. Is 100% when the filter is not inserted in the reflected light of the document, and is 100% when the C filter 16 is inserted in the reflected light of the document at an area ratio of 50%.
The case where the C filter 16 is inserted in the reflected light of the document is shown by the area ratio of%. The R light of 600 to 700 nm is absorbed almost in proportion to the insertion area ratio of the C filter 16 into the reflected light of the original, and the light receiving sheet is exposed by the reflected light of the original having a small amount of R light. Therefore, the photosensitive microcapsules that are exposed to R light (C capsules) are less likely to cure,
The image that is formed is cyan.

By changing the area ratio of the filter inserted in the reflected light of the original, the amount of light reflected by the filter (light of a specific wavelength range) can be adjusted steplessly. That is, B,
The amount of G, R light for image formation exposure can be changed steplessly, and the curing rate of each Y, M, C capsule can be adjusted by the combination, and the step of correcting the photocuring characteristics can be changed steplessly. You can Further, since light is not reflected at the portions where the reflected light of the document is not blocked by the filters 14, 15 and 16, it is possible to minimize the light amount loss. Further, the filters 14, 15 and 16 are in the direction perpendicular to the slit 41 (see arrows B and C in FIG. 1).
Direction), there is no partial color unevenness in the depth direction of the copied image.

In this embodiment, Y, M, and C filters that reflect B, G, and R lights are used, but filters that absorb B, G, and R lights may be used. A filter that absorbs or reflects each light of Y, M, and C may be used. However, in this case, there is a drawback that the light amount loss is large. In addition to the dichroic filter, color PET (polyethylene terephthalate), gelatin filter or the like may be used.

FIG. 2 is a block diagram of a control unit of the copying machine.

Overall control is performed by the CPU 21. The control program is stored in the ROM 22 in advance, and the RAM 23 is used as a working area when executing the program.

The copying machine body 1 is provided with dip switches 31, 32 and 33. The dip switches 31, 32, and 33 correspond to the photo-curing characteristics of the Y, M, and C capsules, respectively, and are each composed of three switches. That is, eight types of characteristic states can be set for each of the Y, M, and C capsules. The on / off instruction of each switch is written on the light-receiving sheet, and when the light-receiving sheet is replaced, the operator turns on / off each switch according to the description, so that the characteristic data for the light-receiving sheet can be obtained. Is entered. The characteristic data is input to the CPU 21 via the I / O 24. CPU21
Then, according to the characteristic data, the number of pulses corresponding to the rotation amount of the stepping motor of the filters 14, 15 and 16 is the area ratio data, and the light amount of each of the B, G and R light sources 42a, 42b and 42c of the auxiliary exposure device is Each is set as auxiliary exposure amount data. The conversion coefficients for setting them are stored in the ROM 2 in advance.

The CPU 21 outputs the area ratio data to the filter control unit 26 via the I / O 25, and the auxiliary exposure amount data to the auxiliary exposure device control unit 27. The filter control unit 26 drives the stepping motors 14a, 15a, 16a based on the area ratio data, and the filters 14, 15, 16 move in the arrow B or C direction. In addition, the auxiliary exposure apparatus control unit 27 is configured so that the B, G, and R light sources 42a, 42
The light quantity control circuits 27a, 27b and 27c of b and 42c are controlled so that the light receiving sheet is subjected to auxiliary exposure with a predetermined light quantity. The setting of the light amount is controlled by, for example, the voltage or duty ratio of each of the B, G, and R light sources.

The setting of the moving amount of the filter and the auxiliary exposure amount according to the sensitivity and gamma of the light receiving sheet by the copying machine having the above-mentioned configuration will be described.

First, the sensitivity correction will be described. For example, the full-color compatible light-receiving sheet prepared here has a photo-curing property as shown in FIG. In this figure, without using the filters 14, 15, 16 and the auxiliary exposure device 42, Y of an image formed by copying a gray scale of 0.05 to 1.85 density of 0.1 density pitch,
The densities of M and C colors were measured, and the horizontal axis represents the exposure amount corresponding to the gray scale density. Regarding the photo-curing property of this light-receiving sheet, the gamma (slope) of each Y, M, C capsule is almost the same, but the sensitivity of the M capsule is low by about 0.6 density, and the formed image becomes reddish or bluish. .

Therefore, in order to correct the sensitivity of the light receiving sheet, the light amount of G is relatively increased by 0.6 density with respect to the light amounts of B and R. The area ratio of each filter covering the image forming exposure light is Y
By setting the filter to 11%, the M filter to 0%, and the C filter to 15%, the characteristic curves of Y and C in FIG. 6 can be matched with the characteristic curve of M, and a good image without specific coloring is obtained. I was able to. In this way, the sensitivity can be corrected. For each production lot of photoreceptor sheet
The sensitivity of each Y, M, C capsule is examined and written on the photoreceptor sheet. The user operates the dip switch based on the description, and the sensitivity is adjusted according to the conversion coefficient stored in the ROM 22 at the positions of the filters 14, 15 and 16 to match the sensitivity of the light receiving sheet. .

Next, gamma correction will be described. For example, another full-color compatible light-receiving sheet prepared here has a photo-curing property as shown in FIG. This figure is similar to the above case, without using the filters 14, 15, 16 and the auxiliary exposure device 42.
Measure the density of each color of Y, M, C formed by copying the gray scale of 0.05 to 1.85 density of 1 density pitch,
The horizontal axis represents the exposure amount corresponding to the gray scale density. The light curing characteristics of this light receiving sheet are Y,
The sensitivities of the M and C capsules were almost the same, but the gamma of all the capsules was large, and the grayscale gradation level was four levels. Therefore, if an image is formed using such a light-receiving sheet, a high-contrast image is obtained, which is unsuitable for copying although it has halftones such as photographs.

Therefore, the voltage of each B, G, and R light source of the auxiliary exposure device 42 is set to B light source: 10.3V, G light source: 3.0V, R light source: 7.0V, and the same gray scale as the above while performing the auxiliary exposure. By copying, the number of gradation steps becomes 6 and halftones can be reproduced. Furthermore, if the same gray scale as the above is copied while performing auxiliary exposure by setting the B light source: 12.0 V, G light source: 6.0 V, R light source: 8.2 V, the gradation step will be 9 steps, and a good copy will be obtained. I was able to get an image. Note that FIG. 8 is a diagram showing the relationship between the exposure amount (grayscale density) and the density of the formed image in this case, and gamma (slope) compared to FIG.
It can be seen that is improved.

In this way, by setting the voltages of the B, G, and R light sources of the auxiliary exposure device, the gamma of the light receiving sheet can be improved and a good image can be formed. The gamma characteristic of each light receiving sheet is inspected for each manufacturing lot of the light receiving sheet and described in the light receiving sheet, similarly to the above-mentioned sensitivity characteristic. The user operates the DIP switches based on the description, and the B, G, R values are calculated based on the conversion coefficients stored in ROM22.
The voltage (light intensity) of each light source is set and the gamma correction suitable for the light receiving sheet is performed.

In this embodiment, the sensitivity is increased by the filters 14, 15 and 16.
Although the gamma is corrected by the auxiliary exposure device 42, the gamma may be corrected by using the filters 14, 15, 16 or the sensitivity may be corrected by the auxiliary exposure device 42.

Also, in this embodiment, as a means for inputting the photo-curing characteristic,
Although eight dip switches are provided for each of Y, M, and C colors, the dip switches can be input, but the number may be any number. In addition to the DIP switch, the photo-curing characteristic may be input by dial input, key input, or the like. In addition, the photocuring property is recorded in the light receiving sheet cassette 2 with a magnetic tape, a bar code, etc.,
The main body 1 may be provided with a device for reading the data, and the light receiving sheet cassette 2 may be attached to the main body 1 to read the data directly. By doing so, it is possible to reduce the burden of data input on the user and prevent input errors and the like.

Furthermore, in this embodiment, the stepping motor is used to move the filters 14, 15 and 16, but if the filter is manually moved mechanically based on the description of the light receiving sheet, the device is simplified, The cost can be reduced. The filters 14, 15 and 16 may be provided in front of the lens 13. Even in that case, if it is provided near the lens 13, there is an advantage that the filter area can be reduced because the image forming exposure light is concentrated.

Further, in this embodiment, using a full-color light receiving sheet, Y, M, C corresponding to each capsule Y, M, C each filter 14, 15,
Although 16 and B, G, R light sources 42a, 42b, 42c are provided, the number of filters and auxiliary exposure devices is changed according to the type of the light receiving sheet,
The type is selected. For example, if the light receiving sheet is coated with photosensitive microcapsules sensitive to ultraviolet rays, a filter that absorbs or reflects ultraviolet rays is used, and an auxiliary exposure device that radiates ultraviolet rays is used.

(G) Effect of the Invention According to the image forming apparatus having the image forming exposure apparatus of the present invention, by changing the minute movement amount of the filter that reflects or absorbs light in the specific wavelength range, the specific wavelength range reflected or absorbed by the filter is changed. Since the amount of light can be changed steplessly, the photo-curing characteristics of the image formed by the light in the specific wavelength range can be changed steplessly. The movement amount of the filter is set on the basis of the inputted photo-curing characteristic, and if the photo-curing characteristic according to the manufacturing lot of the light-receiving sheet is inputted, the photo-curing characteristic is corrected by the filter and a good image is formed. .

[Brief description of drawings]

FIG. 1 is a side view of the vicinity of a lens in a copying machine which is an embodiment of an image forming apparatus having an image forming exposure apparatus of the present invention, FIG. 2 is a block diagram of the copying machine, and FIG. 3 is a schematic configuration of the copying machine. FIG. 4 is a diagram showing the spectral transmittance of the filters (3 types), FIG. 5 is a diagram showing the relationship between the movement amount (area ratio) of the filter and the light amount, FIGS. 6 and 7 Is a diagram showing the photo-curing characteristics of the full-color compatible light-receiving sheet, and FIG. 8 is a diagram showing the characteristics of the light-receiving sheet of FIG. 7 after gamma correction. 13 …… Lens, 14 …… Yellow filter, 15 …… Magenta filter, 16 …… Cyan filter, 14a, 15a, 16a ……
Stepping motors, 31, 32, 33 ... DIP switches.

Claims (1)

[Claims] 1. An image forming apparatus for forming an image by forming image-forming exposure light on a light-receiving sheet through a lens and a slit, which is slightly moved in the direction perpendicular to the slit in the vicinity of the lens. Further, a filter for absorbing or reflecting light of a specific wavelength range of the image forming exposure light is provided, and means for setting a minute movement amount of the filter based on the photo-curing property of the light receiving sheet is provided. An image forming apparatus having an image forming exposure device.