JP2552726B2 - Pressure development method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pressure developing method for forming an image using a light and pressure sensitive sheet.

(B) Conventional Technology A light and pressure sensitive sheet generally comprises a media sheet coated with light and pressure sensitive microcapsules and a receiver sheet coated with a developing material. A latent image is formed on the media sheet by exposure, and a receiver sheet is superposed on the latent image and pressed to develop the latent image. A pressure roller is usually used for this development process (breakdown of the microcapsules on the media sheet).

(C) Problem to be Solved by the Invention By the way, a very high pressure is required for the development processing of the light and pressure sensitive sheet. Therefore, there has been a problem that abrupt torque fluctuation occurs when the light and pressure sensitive sheet is bitten in and released. In particular, torque fluctuations at the time of biting adversely affect the image quality at the leading edge of the image, which is not preferable.

Therefore, it is an object of the present invention to provide a pressure developing method that prevents abrupt torque fluctuations by performing pressure control of a pressure roller device and conveyance control of a photosensitive pressure-sensitive sheet.

(D) Means for Solving the Problem The pressure roller device is made pressure-releasable, pressure is applied when the front end of the photosensitive pressure-sensitive sheet passes, and pressure is released when the rear end passes, thereby causing a rapid torque fluctuation. A device for preventing this is disclosed in JP-A-63-92954. However, in this apparatus, there is no indication about the conveyance control of the light and pressure sensitive sheet.

According to the pressure developing method of the present invention, a photosensitive pressure-sensitive sheet is supplied between the rollers in a state where the pressure of the pressure roller is released, and when the tip of the image corresponding portion of the photosensitive pressure-sensitive sheet reaches the pressure developing point between the rollers, the photosensitive pressure It is characterized in that the pressure sheet is stopped and pressurized to a pressure necessary for the pressure roller pressure developing process, and then the photosensitive pressure sensitive sheet is conveyed to perform the pressure developing process.

e) Function In the present invention, the pressure roller is pressed with the tip of the image corresponding portion of the photosensitive pressure-sensitive sheet stopped at the pressure development point, and after the pressure is increased to the pressure required for the pressure development processing. Then, pressure development is performed. That is, since the sheet is not caught while the pressure roller is in the pressed state, abrupt torque fluctuation does not occur. By the way, since a high pressure is applied to the pressure roller, the pressure operation is performed slowly in order to mitigate the shock. May be displaced from the leading edge of the image. However, in the present invention, the pressure roller is lowered to the leading edge of the image corresponding portion, and the photosensitive pressure-sensitive sheet is conveyed after the pressure is increased to the pressure required for the pressure developing processing (the pressure developing is started). Is started.

(F) Example First, an outline of the image forming apparatus main body will be described.

FIG. 3 is a diagram showing the configuration of an image forming apparatus that forms an image using a light and pressure sensitive sheet. In this embodiment, a light and pressure sensitive sheet consisting of two types of sheets, a media sheet and a receiver sheet, is used, and a roll-shaped medium sheet is used. Therefore, in the media sheet, the conveyance is stopped when the tip of the image corresponding portion (latent image) reaches the pressure development point, and in the receiver sheet, the conveyance is stopped when the tip of the sheet reaches the pressure development point. It is like this.

An original table 1 made of a transparent hard glass body is provided on the upper surface of the image forming apparatus main body. The document A to be copied is placed on the document table 1 with the document surface facing down. Platen 1
An optical system is provided below. Optical system 2 is light source 2
a, 2b, mirrors 2c to 2f, lens 2g, and filter 2h. The document A on the document table 1 is exposed by light sources 2a and 2b, and the reflected light is guided to an exposure point described later via mirrors 2c to 2f, a lens 2g, and a filter 2h. The filter 2h has a plurality of filters having different transmission wavelengths, and performs color correction of the document reflected light by adjusting the amount of each filter inserted into the optical path. The insertion amount of the filter is determined according to the sensitivity characteristics of the media sheet, the image color desired by the user, and the like.

A slide projector 3 is provided on the right side of the main body of the image forming apparatus.
However, it is provided detachably. The slide projector 3 has a light source 3a, a slide holder 3b, and a lens 3c. A slide film to be printed is inserted into the slide holding section 3b. On the other hand, the mirror 2f of the optical system for reflected light of the document is rotatable, and is rotated by about 90 degrees by rotating a handle (not shown) provided on the front side of the image forming apparatus main body. It When the mirror 2f is rotated (indicated by the chain double-dashed line in the figure), the slide holder
The transmitted light of the slide film inserted in 3b is guided to the exposure point via the lens 3c. The lens 3c is also provided with a color correction filter.

A mounting portion for a media sheet is provided on the left side in the image forming apparatus main body. The media sheet 4 is made of a light-curable material,
It is coated with microcapsules having a particle size of about 10 to 20 μm enclosing a coloring dye or the like. The microcapsules are hardened by exposure and destroyed by pressure, causing the chromogenic dye to flow out. This media sheet becomes a photosensitive and pressure-sensitive sheet in combination with a receiver sheet described later. The receiver sheet is obtained by applying a thermoplastic resin and a developing material (which develops the coloring dye) onto paper.

The media sheet 4 is wound around a supply shaft 51, housed in a storage chamber R of a media cartridge 5 made of a light shielding material, and protected from external light and external pressure. The supply shaft 51 can be locked by a ratchet mechanism including a solenoid. The media cartridge 5 also includes a take-up shaft 52, and a used media sheet is taken up on the take-up shaft 52. Winding shaft
52 is always urged in the winding direction to prevent the media sheet 4 from becoming loose. Replacement of the used media sheet 4 is performed for the entire cartridge 5.

The replacement of the media cartridge 5 is performed by taking the media cartridge 5 in and out. The bucket 6 is provided so as to be pulled out along the sliders 61, 61 on the front side of the image forming apparatus main body, and the media cartridge 5 can be inserted from above. A tractor roller 62 is provided at the upper right end of the bucket 6. A pin 62a is provided around the end of the tractor roller 62. On the other hand, in the new media cartridge 5, the leading end of the media sheet 4 is slightly pulled out from the opening 53 of the storage chamber R. This is pulled out by hand and hooked on the tractor roller 62. A leader sheet, which is strongly stiff and slightly wider than the media sheet, is attached to the end of the media sheet, and the holes formed at both ends of the leader sheet are the pins of the tractor roller 62.
It can be hung on 62a. When the leader sheet is hooked on the tractor roller 62 and the bucket 6 is pushed into the image forming apparatus main body, the bucket sensor S1 is turned on, and when the front cover of the image forming apparatus main body is closed, the cover switch S2 is turned on. When both of them are turned on, automatic loading of the media sheet (automatic setting of the media sheet) is performed.

An exposure table 7, a buffer roller 8, and a pressure developing device 9 are provided on the right side of the media sheet mounting portion. At the time of initial setting, the media sheet hung on the tractor roller 62 is taken up by the take-up shaft 52 via the exposure table 7, the buffer roller 8 and the pressure developing device 9 by automatic loading. The above-described document reflected light or slide transmitted light is guided to the exposure point P1 on the exposure table 7 to expose the media sheet 4. Then, a latent image (an image in which a partial microcapsule is hardened) corresponding to the document or the slide image is formed on the media sheet 4. Reference numeral 71 is a heater that is turned on at the time of exposure, and the media sheet 4 is provided in order to keep it constant because the cross sensitivity changes depending on the temperature.

4 (A) and 4 (B) are views showing the configuration of the pressure developing device. The pressure developing device 9 has upper and lower pressure rollers 91 and 92. Pressure development point P between upper and lower pressure rollers 91 and 92
Is 2. The upper pressure roller 91 is held by the upper holder 93 so as to be movable in the vertical direction. Backup rollers 91a and 91b are rotatably held above the upper pressure roller 91. The lower pressure roller 92 is rotatably held by the lower holder 94. The upper and lower holders 93, 94 are rotatably provided around a fulcrum shaft 95, and a spring 96 and an eccentric cam 97 apply pressure and pressure. When the upper and lower holders 93 and 94 are pressed, the upper and lower pressure rollers 91 and 92 are naturally pressed (FIG. 4 (A)). At this time, the upper pressure roller is urged downward by the backup rollers 91a and 91b, so that a uniform pressure can be obtained in the axial direction. And the upper and lower holders 93,94
When the pressure is released, the upper and lower pressure rollers 91, 92 are also released (FIG. 4 (B)). The upper and lower pressure rollers 91, 9
No. 2 is pressurized only at the time of pressure development, and in the other cases, the pressure is released.

The buffer roller 8 is provided so as to be movable in the directions of arrows B and C in the figure. This movement is performed by a motor (not shown). In this image forming apparatus, the pressure development step is performed after the exposure step is completed. This is because the exposure speed and the pressure development speed are set separately, so that the image quality can be improved. The buffer roller 8 is a medium sheet conveying speed (exposure speed and pressure developing speed)
Used to change the. In the exposure step, exposure is performed while moving the backup roller 8 in the direction of arrow B.
Then, the media sheet 4 on which the latent image is formed is stored in the buffer unit at the upper right of the exposure table. When the exposure is completed, the backup roller 8 moves in the direction of arrow C and sends out the media sheet 4 on which the latent image is formed to the pressure developing device 9. At this time, the receiver sheet is overlaid on the latent image of the media sheet 4 and pressed together.

A paper cassette 10 is provided on the right side of the image forming apparatus main body. The sheet cassette 10 stores the receiver sheet 11 and is sent out by the sheet feeding device 12. The receiver sheet 11 sent out by the paper feeding device 12 is temporarily stopped by the timing roller 13 and is fed at the timing of being superimposed on the latent image on the media sheet.

If the media sheet 4 and the receiver sheet 11 are overlaid and pressurized, the uncured microcapsules are broken and the chromogenic dye flows out. The dye develops a color with the developing material and forms an image on the receiver sheet. After this, the two sheets are peeled off, the media sheet 4 is wound around the winding shaft 52, and the receiver sheet is sent to the glossing device 20. The glossing device 20 heats and presses the receiver sheet 11 so that the resin on the sheet is in a softened state, covers the image surface, and further smoothes it. This gives the image a high gloss. Further, this heating accelerates the color forming reaction of the color forming dye. The image formed in this way is discharged to the discharge tray 21 on the left side of the image forming apparatus main body.

Next, the conveyance control of the receiver sheet according to the present invention will be described in detail.

FIG. 1 is a time chart relating to conveyance of a media sheet and a receiver sheet during image formation. Further, FIGS. 2A to 2C are enlarged views in the vicinity of the pressure developing device for explaining this step.

When the print switch is operated, the supply shaft 51 is unlocked and the media sheet 4 can be pulled out. Then, from t _{1 to} t ₂ , the buffer roller 8 starts moving in the direction of the arrow B, and the optical system (for original scanning or slide exposure) operates, so that the media sheet 4 is placed on the exposure table 7.
Is exposed to form a latent image. By the way, the area of the latent image on the media sheet at the end of exposure is 1 in FIG. 2 (A).
Is. The position of P1 of the exposure table 7 at the start of exposure is the leading end position of the latent image, and before that, it is the non-image forming area 1 '. Therefore, in this device, the receiver sheet
Before feeding 11 sheets, the non-image forming area 1'is taken up by the take-up shaft.
I try to wind it up to 52. In t ₂ ~t ₄ to move the buffer roller 8 while locking the supply shaft to the direction of arrow C, buffer roller 8 is stopped when the tip of the latent image l reaches P2. The media sheet 4 loosened by the movement of the buffer roller 8 is wound around the winding shaft 52. During the movement of the buffer roller, the timing roller 13 starts rotating at t ₃ and supplies the receiver sheet 11 to P 2. The tip of the receiver sheet 11 of the timing roller 13 is P2.
It stops at time t ₄ (see FIG. 2 (B)). By the above control, the tips of the image corresponding portions of both sheets 4 and 11 (light and pressure sensitive sheets) correspond to the pressure development point P2.

Then the upper and lower pressure rollers 91 and 92 is pressurized to a pressure necessary for the pressure developing process (t ₄ ~t _5). At this time, since the conveyance of the media sheet 4 and the receiver sheet 11 is stopped, the pressing point does not deviate. Both seats
When 4,11 are sufficiently pressurized, the upper and lower pressure rollers 91,92 rotate and the buffer roller 8 moves in the direction of arrow C to perform the pressure developing process. That is, the uncured microcapsules on the media sheet 4 are destroyed, and the outflowing color forming dye is colored by the developing material of the receiver sheet 11 to form an image. Buffer roller 8 returns to the home position t _6, thereafter the pressure development is performed media sheet 4 is fed only by the rotation of the upper and lower pressure rollers 91 and 92 in a state where the buffer roller 8 is stopped (FIG. 2 (C )
reference).

When the pressure developing process is completed at t ₇ , the pressures of the upper and lower pressure rollers 91 and 92 are released. The pressure relief when t ₇ ~t ₈ vertical pressure rollers 91 and 92 continue to rotate, the media sheet 4
And the receiver sheet 11 is sent to the paper discharge side. When releasing the pressure, the media sheet 4 and receiver sheet
The pressure may be released while the transportation of 11 is stopped.

(G) Effects of the Invention As described above, according to the present invention, since the leading end of the image forming area of the light and pressure sensitive sheet (media sheet and receiver sheet) can be reliably set as the development start point, the leading end of the image is There is no chipping. Further, since the sheet is inserted in the pressure released state and then the pressure is applied, abrupt torque fluctuation does not occur. Further, the photosensitive pressure-sensitive sheet is stopped until the pressure required for the pressure development processing is applied, and the pressure-sensitive sheet is conveyed after being pressed to the pressure required for the pressure development processing. To do
There is no problem that the development start point deviates from the front end of the image.

[Brief description of drawings]

FIG. 1 is a time chart showing an example of pressure development processing, FIGS. 2 (A) to 2 (C) are views showing the state of the pressure developing device at the time of pressure development, and FIG. 3 is an image using a photosensitive pressure-sensitive sheet. 4A and 4B are schematic configuration diagrams of the forming apparatus, showing the pressure developing apparatus. FIG. 4A shows a state when pressure is applied, and FIG. 4B shows a state when pressure is released. It represents.

Claims (1)

(57) [Claims] 1. A photosensitive pressure-sensitive sheet is supplied between the rollers in a state where the pressure roller is depressurized, and the photosensitive pressure-sensitive sheet is removed when the tip of the image corresponding portion of the photosensitive pressure-sensitive sheet reaches a pressure development point between the rollers. A pressure developing method comprising stopping and pressurizing the pressure roller to a pressure necessary for pressure developing processing, and then carrying the light and pressure sensitive sheet to perform pressure developing processing.