JPH02301757A - Pressure developing method - Google Patents

Abstract

PURPOSE:To prevent creases of a media sheet at the time of pressure development by returning a buffer roller at a speed of <=1/2 of a peripheral speed of a pressure developing roller and executing a pressure development processing. CONSTITUTION:A media sheet 4 is drawn out of a supply shaft by moving a buffer roller 8 in the direction being roughly orthogonal to a media sheet carrying path, and thereafter, pressure developing rollers 91, 92, are rotated and also, the buffer roller 8 is returned at a speed of <=1/2 of a peripheral speed of the pressure developing rollers 91, 92 and a pressure development processing is executed. Accordingly, the speed of the media sheet 4 fed into the pressure developing rollers 91, 92 is set to the same as the peripheral speed of the pressure developing rollers 91, 92 or below. In such a way, it does not occur that looseness is generated in the media sheet 4 between the pressure developing rollers 91, 92 and the buffer roller 8 and creases are not generated either.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Field of Application This invention forms an image while winding a media sheet wound around a supply shaft through an exposure section, a pressure developing roller, and winding it onto a take-up shaft. The present invention relates to an improvement in a pressure developing method in an image forming apparatus.

(bl Prior Art) In recent years, the development of image forming apparatuses that form images using media sheets coated with photosensitive and pressure-sensitive microcapsules has been progressing. To protect it from external pressure, it is wound around a supply shaft and housed in a cartridge when not in use.

Then, during image formation, it is pulled out from the cartridge, passes through an exposure section and a pressure developing roller, and is wound onto a winding shaft. The supply shaft and take-up shaft are biased in opposite directions to apply tension to the media sheet.

When forming an image using a media sheet, it is preferable to change the conveyance speed of the media sheet between exposure and pressure development. This is because it takes time to destroy the microcapsules (pressure development). Therefore, conventionally, a buffer roller supported movably in a direction substantially perpendicular to the conveying direction of the media sheet has been provided between the exposure section and the pressure developing roller.

During exposure, the buffer roller moves in a direction substantially perpendicular to the first general feeding direction of the media sheet to pull out the media sheet, and each time it returns after exposure, the exposed media sheet is fed to the pressure developing roller.

(C1) The problem to be solved by the invention is that in the conventional apparatus, wrinkles may occur in the media sheet during pressure development.

In conventional devices, the movement of the buffer roller is controlled by a motor when pulling out the media sheet (during exposure), but during pressure development, the rotation of the pressure development roller pulls the media sheet and moves it in the return direction. was. In this case, a certain amount of load was applied to the buffalo roller by a torque limiter to prevent the return speed of the buffalo roller from becoming too fast, but the moving speed of the buffalo roller and the rotational speed of the pressure developing roller were perfectly balanced. It is very difficult to
Furthermore, the moving speed of the buffer rJ-ra may change due to changes in temperature and the like, resulting in deviation from the rotational speed of the pressure developing roller. It is thought that this misalignment caused wrinkles in the media sheet.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pressure development method that prevents wrinkles of a media sheet during pressure development.

(Means for Solving Problem d1) The present invention provides a pressure development method in an image forming apparatus in which a media sheet wound around a supply shaft is wound onto a take-up shaft via an exposure section, a roller roller, and a pressure development roller. Then, the media sheet was pulled out from the supply shaft by moving the buffer roller in a direction substantially perpendicular to the media sheet conveyance path. It is characterized in that the pressure development process is performed by returning at a speed of 2 or less of the circumferential speed.

When the te1 action buffer roller is returned at the speed of the pressure developing roller, the circumferential speed of the pressure developing roller and the feeding speed of the media sheet sent out by the buffer roller match. In the pressure development method of this invention, the return speed of the buffer roller during exposure is set to 2 or less of the circumferential speed of the pressure development roller, and the speed of the media sheet fed to the pressure development roller is set to the circumferential speed of the pressure development roller. Since the value is set to be the same as or less than , the media sheet does not become loose between the pressure developing roller and the buffer roller, and wrinkles are less likely to occur.

if) Example An outline of the image forming apparatus main body will be explained.

FIG. 3 is a diagram showing the configuration of an image forming apparatus equipped with a pressure developing roller.

<Exposure Device> A document table 1 made of transparent hard glass is provided on the top surface of the main body of the image forming apparatus. A document A to be copied is placed on the document table 1 with the document surface facing downward. An optical system is provided below the document table 1. Optical system 2 is light source 2a
, 2b, mirrors 2c to 2f, lens 2g, filter 2h
have. The document A on the document table 1 is exposed to light by the light sources 2a and 2b, and the reflected light is reflected by the mirrors 20 to 2f and the lens 2g.
, and are guided to an exposure point, which will be described later, via a filter 2h. Note that the filter 2h has a plurality of filters having different transmission wavelengths, and performs color correction of the light reflected from the document by adjusting the insertion amount of each filter into the optical path. The amount of filter insertion is determined depending on the sensitivity characteristics of the media, the image color desired by the user, etc.

A slide projector 3 is detachably provided on the right side of the image forming apparatus main body. slide projector 3
includes an optical fi 3a, a slide holding portion 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 reflecting light from the original is rotatable, and can be rotated approximately 90 degrees by rotating a handle (not shown) provided on the front side of the image forming apparatus main body. Ru. mirror 2f
When the slide image is rotated (the state indicated by the two-dot chain line in the figure), the transmitted light from the slide film inserted into the slide image section 3b is guided to the exposure point via the lens 3c. The lens 3c is also equipped with a filter for color correction.

<Media Cartridge> A media sheet mounting section is provided on the left side of the main body of the image forming apparatus. Media seals 1 to 4 are obtained by applying microcapsules having a particle size of about 10 to 20 μm and encapsulating a photocurable material 2, such as a color-forming dye, on a sheet I made of a light-reflecting material such as aluminum. The microcapsules are cured by exposure to light and destroyed by pressure, allowing the color-forming dye to flow out. This media sheet is paired with a receiver sheet to be described later to form a photosensitive pressure sensitive sheet 1-. Note that the receiver 1 is a sheet of paper coated with a thermoplastic resin and a developing material (that causes the color-forming dye to develop color).

The media sheet 4 is wound around a supply shaft 51, and is housed in a light-shielding storage chamber R of the media cartridge 5, where it is protected from external light and external pressure. The supply shaft 51 is always urged in the direction opposite to the drawing direction, and can be locked by a ratchet mechanism including a solenoid. The media cartridge 5 also includes a take-up shaft 52, and the used media sheet is wound onto the take-up shaft 52. The winding shaft 52 is always biased in the winding direction to prevent the media sheet 4 from becoming slack. The used media sheet 4 is replaced with the entire cartridge 5.

The media cartridge 5 is replaced by taking it in and out of the bucket 6. The bucket 6 is provided so as to be able to be pulled out from the front side of the image forming apparatus main body along sliders 61 and 61, 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 62 is provided around the end of the tractor roller 62.
A is provided. 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 onto the tractor roller 62. A leader sheet that is strong and slightly wider than the media sheet 1 is attached to the tip of the media sheet, and holes formed at both ends of the leader sheet are attached to the bin 6 of the tractor roller 62.
Can be multiplied by 2a. Place the leader sheet on the tractor roller 62.
When the bucket 6 is pushed into the main body of the image forming apparatus by hooking it to the main body of the image forming apparatus, the bucket sensor S1 is turned on, and when the front cover of the main body of the image forming apparatus is closed, the cover switch S2 is turned on. By turning on both of these, automatic loading of the media sheet (automatic centing of the media sheet) is performed.

<Exposure Section and Pressure Development Section> An exposure table 7, a buffer roller 8, and a pressure development device 9 are provided on the right side of the media sheet mounting section. At the initial stage, the media sheet I, which has been hung on the tractor roller (i2), is wound onto the winding shaft 52 via the exposure table 7, the buffer roller 8, and the pressure developing device 9 by OI loading. The above-mentioned original reflected light or slide transmitted light is guided to the exposure point PI on the exposure table 7, and exposes the media sheets 1 to 4. Then, a latent image (an image of partially hardened microcapsules) corresponding to the original or the slide image is formed on the media sheet 4. Note that 71 is a heater that is turned on during exposure, and since the light sensitivity of the media sheet 4 changes depending on the temperature, it is provided to keep it constant.

The pressure developing device 9 has upper and lower pressure rollers 91,92. The pressure development point P is between the upper and lower pressure rollers 91 and 92.
It is 2. Above the upper pressure roller 91, hack-up rollers 94a and 91b are provided which apply a uniform downward urging force to the upper pressure roller 91 in the axial direction. The upper and lower pressure rollers are pressurized, the pressure is adjusted, and the pressure is released by means of a spring and a cam (not shown). Note that the upper and lower pressure rollers 9192 are applied with appropriate pressure only during pressure development, and are in a pressure-released state at other times.

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, which will be described later. In this image forming apparatus, the pressure development process is performed after the exposure process is completed. This is because the exposure speed and pressure development speed are set separately, and image quality can be improved. buffalo 8
is used to change the transport speed (exposure speed and pressure development speed) of the media sheet. FIG. 1 is a perspective view showing the vicinity of the buffer roller, and FIG. 2 is a plan view of the buffer roller drive section.

In FIG. 1, the buffer roller 8 is pivotally supported by a guide 81. As shown in FIG. A bearing portion 81a is provided at one end of the guide 81.
is formed, and a support rod 82 fixed to the image forming apparatus main body is fitted into this bearing portion 81a.
Slide along 2. The longitudinal direction of the support rod 82 is the direction of arrows B and C in FIG. Further, a colco 81b is pivotally supported at the other end of the guide 81, and a rail 83a,
Rotate between 83 and b. A loop-shaped wire 84 is fixed to the middle part of the guide 81. The wire 84 coming out from one wall of the guide 81 is wound around a winding roller 85 fixed to the shaft 8G, and then passed through a pulley 89 arranged on the side of the upper pressure roller 91 to the guide 81. Return to the opposite wall. If the shaft 86 (winding roller 85) rotates in the direction indicated by the arrow, the buffer roller 8 (guide 81) moves in the direction of arrow B, and if the shaft 86 rotates in the direction of arrow E, the buffer roller 8 moves in the direction of arrow C. do.

In FIG. 2, the shaft 86 is supported by the frame 22 of the main body of the image forming apparatus, and the rotation of the motor 87 is controlled by the gears 88a to 88.
f to the shaft 86.

The rotational direction and rotational speed of the shaft 86 are determined by the rotational direction and rotational speed of the motor 87.

During the exposure process, exposure is performed while moving the hack up roller 8 in the direction of arrow B. Then, the media sheet 4 on which the latent image is formed is stored in the upper right corner of the exposure table. When the exposure is completed, the hack up 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 moving speed of the roller roller 8 is set to two or less of the circumferential speed of the pressure developing rollers 91 and 92, and a light tension is applied to the media sheet 4. Therefore, no wrinkles occur in the media sheet. During pressure development, media sheet 4
Receivers 1 to 1 are superimposed on the latent image and pressurized together.

A lock roller 93 is provided downstream of the pressure developing device 9. The lock roller 93 is supported by a shaft so that it can move up and down, and is moved by, for example, a solenoid. When the lock roller 93 moves downward, it comes into pressure contact with the lower pressure roller 92. When the lock roller 93 moves downward while the media sheet 4 is hung between the supply shaft 511 and the take-up shaft 52, the media sheet 4 is moved to the lock roller 93. It comes to be held between the lower pressure rollers 02. This narrow 1) force only needs to be small, and when the buffalo roller 8 is in the locked state, the arrow B
It may be sufficient to lock the media sheet from being pulled out from the take-up shaft 52 when it moves in the direction. Therefore, it can be locked using a simple solenoid mechanism.

<Paper Feeding Unit and Paper Discharging Unit> A paper cassette 10 is provided on the right side of the main body of the image forming apparatus. A receiver sheet 11 is placed in the paper cassette 10.
is stored and sent out by the paper feeding device 12. Note that the receiver sheet 1 fed out by the paper feeder 12
1 is temporarily stopped by a timing roller 13, and is fed at the timing when it is overlapped with the gap on the media sheet.

When the media sheet 4 and the receiver sheet 11 are stacked and pressurized, the uncured microcapsules are destroyed and the coloring dye flows out. The dye is developed by the developer material and forms an image on the receiver sheet. This rear sheet is peeled off, the media sheet 4 is wound onto the take-up shaft 52, and the receiver sheet is sent to the glossing device 20. The glossing device 20 heats and presses the receiver sheet 11 to soften the resin on the sheet to cover the image surface and smooth it. This gives the image a high gloss. This heating also accelerates the color-forming reaction of the color-forming dye. The images thus created are discharged onto paper discharges 1 to 21 on the left side of the main body of the image forming apparatus.

Next, conveyance control of a media sheet during pressure development according to the present invention will be explained.

FIG. 4 shows a quim chart 1 for conveying a media sheet and receiver 1 during image formation.

Further, FIGS. 5A to 5C are enlarged views of the vicinity of the pressure developing device for explaining this process.

In the normal state, the lock roller 93 moves downward and locks the media sheet 4. When the print 1 switch is operated, the supply shaft 51 is unlocked and the media sheet 4 can be pulled out. Then, from t1 to t2, the buffer roller 8 starts moving in the direction of arrow B, and the optical system (for document scanning or slide exposure) is activated, and the media sheet 4 is exposed on the exposure table 7 to form a latent image. (See 5th FI (A)). At this time, the lock roller 93 remains in the locked state, and the withdrawal of the media sheet 4 from the take-up shaft 52 is locked, and the supply shaft 5
The area of the latent image on the media sheet at the end of exposure, where the latent image is only drawn out from 1, is β in the figure. The position at Pl of the exposure table 7 at the start of exposure becomes the leading edge position of the latent image, and the area before that becomes the non-image forming area β'. Therefore, in this device, before feeding the receiver sheet 11, the non-image forming area β' is wound onto the winding shaft 52. First, after the end of exposure t2, the lock roller 93 is unlocked. Then, from t2 to t4, the buffer roller 8 is moved in the direction of arrow C with the supply shaft locked, so that the tip of the latent image l becomes P
2, the buffer roller 8 stops. The media sheet 4 loosened by the movement of the buffer roller 8 is wound up on the take-up shaft 52. Note that the moving speed of the buffer roller 8 in the direction of arrow C at this time may be arbitrary. During the movement of the buffer roller, timing roller 1 at t.
3 starts rotating and supplies the receiver sheet 11 to P2. The timing roller 13 stops at a facing point t4 (see FIG. 5(B)) where the tip of the receiver 1 reaches P2. With the above control, both seas 1-4. The leading edge of the i1 image corresponds to the pressure development point P2.

Next, the upper and lower pressure rollers 91 and 92 are pressurized (t4 to t
s). At this time, since the conveyance of the media sheet 4 and receiver sheet 11 is stopped, the pressure point does not shift. When both the sheets 1-/1.11 are sufficiently pressurized, the upper and lower pressure rollers 91 and 92 rotate, and the buffer roller 8 moves in the direction of arrow C to perform pressure development processing. The moving speed of the buffer roller 8 at this time is set to 2 or less of the circumferential speed of the pressure developing rollers 91 and 92. As a result, the media sheet does not become loose between the buffer roller 8 and the pressure developing roller, and wrinkles can be prevented. At this time, the supply shaft 51 is unlocked, so even if the moving speed of the buffer roller 8 is slightly delayed, the media sheet will not be overstretched and torn.

The uncured microcapsules on the media sheet 4 are destroyed by the pressure applied by the pressure developing roller, and the color-forming dye that flows out is colored by the developing material of the receiver sheet 11 to form an image. The buffalo roller 8 returns to the home position at t6, and from then on, with the buffalo roller 8 stopped, the media sheet 4 is fed only by the rotation of the upper and lower pressure rollers 91 and 92, and pressure development is performed (Fig. 5(C)
)reference).

When the pressure development process ends at t7, the pressure on the upper and lower pressure rollers 91 and 92 is released. 7~ even when pressure is released
At t8, the upper and lower pressure rollers 91 and 92 continue to rotate and send out the media sheet 4 and receiver sheet 11 to the paper discharge side. Note that when the pressure is released, the pressure may be released while the conveyance of the media sheet 4 and the receiver sheet 11 is stopped. When the pressure is released, the lock roller 93 moves downward again to lock the media sheet 4.

(g) Effects of the Invention As described above, according to the present invention, the media sheet does not become loose during pressure development, and the media sheet can be prevented from wrinkling.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the vicinity of the buffalo roller used in an embodiment of the present invention, Fig. 2 is a diagram of the buffalo roller drive section, Fig. 3 is a schematic diagram of the entire image forming apparatus, and Fig. 4 is an example of pressure development processing. FIGS. 5A to 5C are diagrams showing the state of the pressure developing device during pressure development. 4-) Deer sheet, 8-buffer roller, 84-wire, 85-winding roller, 86-shaft, 87-motor, 88
a~88f-gear.

Claims (1)

[Claims] (1) A pressure development method in an image forming apparatus in which a media sheet wound around a supply shaft is wound onto a take-up shaft via an exposure section, a buffer roller, and a pressure development roller, the media sheet being conveyed by the buffer roller. After pulling out the media sheet from the supply shaft by moving it in a direction substantially perpendicular to the path, the pressure developing roller is rotated and the buffer roller is moved at a speed of 1/2 or less of the circumferential speed of the pressure developing roller. A pressure development method characterized by performing pressure development processing with return.