JP2636959B2 - Image forming device - Google Patents

Description

The present invention relates to, for example, a photosensitive sheet coated with microcapsules containing a photocurable material and a coloring dye, and a developing material which reacts with the coloring dye to form a color. TECHNICAL FIELD The present invention relates to an image forming apparatus that forms an image by applying pressure in a state where an image receiving sheet coated with is superposed.

(Prior Art) For example, JP-A-58-88739 discloses a photosensitive sheet coated with a microcapsule containing a photocurable material and a coloring dye, and a developing material which reacts with the coloring dye to form a color. An image forming apparatus for forming an image using a coated image receiving sheet is disclosed.

In such an image forming apparatus, an image is formed as follows. First, when a document image is exposed on a photosensitive sheet, the microcapsules in the light-irradiated portion are selectively cured to form a latent image corresponding to the document image. The photosensitive sheet on which the latent image is formed is overlaid on the image receiving sheet coated with the developing material by a pressure device as a pressure developing unit, and both are pressed. As a result, the uncured microcapsules on the photosensitive sheet are destroyed, the coloring dye contained therein flows out, and the discharged coloring dye reacts with the developing material on the image receiving sheet to form a color. Thus, an image corresponding to the document image is formed on the image receiving sheet.

The photosensitive sheet is accommodated in a state wound around a supply shaft in a cartridge, is pulled out from the cartridge by a buffer roller, passes through an image exposure step and a pressure development step, and then rewinds in the cartridge. It is wound on a take-up spindle.

As shown in FIG. 3A, an exposure plate 101 is arranged at an image exposure position for the photosensitive sheet 103 pulled out from the cartridge, and a guide roller 102 is arranged below the exposure plate 101. . The buffer roller 100 is disposed below the guide roller 102. The buffer roller 100 is shown by an arrow A in FIG.
When the buffer roller 100 moves in the direction shown by the arrow A, the photosensitive sheet 103 is pulled out of the cartridge and is sequentially conveyed along the exposure plate 101. You.

The guide roller 102 is positioned so that the photosensitive sheet 103 conveyed along the exposure plate 101 is slightly pressed in the direction opposite to the direction in which the buffer roller 100 is pulled out (the direction of arrow B).

The buffer roller 100 is in a state along the moving direction of the photosensitive sheet 103 on the exposure plate 101 with respect to the guide roller 102 before the next image is exposed after one cycle of the image forming operation is completed. An exposure start position t which is away from the constant-speed withdrawal start position t 'of the sheet 103 by the approach distance m in a direction opposite to the direction in which the buffer roller 100 is withdrawn.
It has become. With the buffer roller 100 in such an exposure start position t, the buffer roller 100
Is moved in the pull-out movement direction indicated by the arrow A, and the exposure of the photosensitive sheet 103 to the image is started. Accordingly, the buffer roller 100 is set at a predetermined speed while passing through the approach distance m, and moves at a constant speed when passing through the drawing start position t ′. Is withdrawn at a constant speed. Since the moving speed is not constant while the buffer roller 100 moves the approach distance m, the image exposed on the photosensitive sheet 103 during that time may be blurred. However, since that portion is a void portion where an image is not formed on the image receiving sheet, there is no hindrance to the image forming operation.

(Problem to be Solved by the Invention) In such an image forming apparatus, as shown in FIG. 3B, when the buffer roller 100 reaches the constant speed withdrawal position t ', the photosensitive sheet 103 is moved to the guide roller. If there is no looseness in close contact with the peripheral surface of 102, the photosensitive sheet 103 can be smoothly pulled out by the pulling-out operation of the buffer roller 100 in the pulling-out direction, and an image without blur can be formed. However, as shown in FIG. 3C, when the photosensitive sheet 103 is in a loose state in which the photosensitive sheet 103 does not adhere to the peripheral surface of the guide roller 102, even after passing through the constant speed movement start position t ', There is a problem that an image exposed on the photosensitive sheet 103 is blurred until the drawing speed of the photosensitive sheet 103 is not constant and the photosensitive sheet 103 is not loosened.

The present invention is to solve such problems, the purpose of which is to eliminate the loosening of the photosensitive sheet before the start of exposure,
An object of the present invention is to provide an image forming apparatus capable of preventing an image from being blurred due to the loosening.

(Means for Solving the Problems) In the present invention, an image is exposed while a photosensitive sheet coated with a photosensitive pressure-sensitive material is conveyed, and the exposed photosensitive sheet is overlapped with an image receiving sheet coated with a developing material. In an image forming apparatus that also performs pressure development, the photosensitive sheet can be reciprocated in a direction orthogonal to the conveying direction of the photosensitive sheet, and the photosensitive sheet is pulled out by moving in one direction, and the photosensitive sheet is moved at a constant speed. A buffer roller that conveys at least three positions on a moving path in one direction of the buffer roller, that is, a constant speed drawing position at which the photosensitive sheet reaches a constant speed, and a direction opposite to the one direction. The exposure start position is separated from the constant-speed withdrawal position, and the home position is further away from the constant-speed withdrawal position with the exposure start position. When the buffer roller is positioned at the home position, the photosensitive sheet is taken up, and prior to exposure of an image, the buffer roller is moved from the home position to the exposure start position to tension the photosensitive sheet. In addition, during the exposure of the image, the buffer roller is moved from the exposure start position to the constant speed withdrawal position, and the buffer roller is moved to continuously withdraw the photosensitive sheet. Thereby, the above object is achieved.

(Operation) In the image forming apparatus of the present invention, the photosensitive sheet is wound when the buffer roller is positioned at the home position, but the photosensitive sheet is loosened by the rewinding of the winding. By moving the buffer roller from the home position to the exposure start position, tension is applied to the photosensitive sheet to remove looseness of the photosensitive sheet, and during subsequent image exposure, the buffer roller is moved at a constant speed from the exposure start position. The buffer roller is moved in order to move to the draw-out position and subsequently pull out the photosensitive sheet.

As a result, when the exposure of the image is started, the photosensitive sheet quickly reaches the drawing speed, and the speed of the photosensitive sheet is not disturbed, and the image is not blurred.

(Example) An example of the present invention will be described below.

FIG. 2 is a front longitudinal sectional view of a copying machine employing the image forming apparatus of the present invention. The copying machine has a glass document table 2 provided on the upper surface of a copying machine body 1. A document 3 for forming a copy image is placed on the document placing table 2. A light-transmitting sheet projecting section 4 for projecting an image formed on the light-transmitting sheet into the copying machine main body 1 is provided at an upper portion of one side surface of the copying machine main body 1, and is provided below the light-transmitting sheet projecting section. Is provided with a manual paper feed unit 5 and a paper feed cassette 6. The sheet cassette 6 contains, for example, an image receiving sheet 7 coated with an acidic developing material. The image receiving sheet 7 is superposed on the photosensitive sheet and is subjected to pressure development, whereby an image is formed on the image receiving sheet 7. On the other side of the copying machine body 1, there is provided a paper discharge tray 8 on which the image receiving sheet 7 on which an image has been formed is placed.

An optical system 10 is provided above the copying machine body 1. The optical system 10 includes a pair of light sources 11 for irradiating the original 3 placed on the original placing table 2 on the upper surface of the copying machine main body 1 with light.
The light sources 11 and 12 can reciprocate in the direction indicated by the arrow C and in the opposite direction. Light emitted from the light sources 11 and 12 and reflected from the document 3 is reflected in a direction opposite to the direction indicated by the arrow C by the mirror 13 that moves integrally with the light sources 11 and 12. The light reflected by the mirror 13 is a mirror case
The traveling direction is reversed by a pair of reflection mirrors 15 and 16 in 14. The light whose traveling direction is reversed by the pair of mirrors 15 and 16 passes through the lens unit 17,
The light is reflected by the mirror 18 and radiated toward an exposure plate 30 provided substantially at the center of the copying machine body 1.

A cooling fan 65 for cooling the pair of light sources 11 and 12 is attached to the optical system 10.
Reciprocates integrally with both light sources 11 and 12.

Below the mirror case 14, a photosensitive sheet bucket 20 is provided.
Are arranged. A cartridge 21 covered by a case made of a light-shielding material is mounted on the photosensitive sheet bucket 20. The cartridge 21 has a roll-shaped photosensitive sheet 23 that is wound and housed around an internal supply shaft 22. The photosensitive sheet 23 is formed by coating a base sheet made of a metal, a synthetic resin, or the like with microcapsules, which are photosensitive pressure-sensitive materials having a particle size of about 10 to 20 μm and containing a coloring dye such as a leuco dye and a photocurable substance. ing. The photosensitive sheet 23 is pulled out via a guide roller 26 arranged near the supply shaft 22.

Positioning holes (not shown) for use in sequentially feeding out the photosensitive sheet 23 from the photosensitive sheet bucket 20 are provided along both sides in the width direction of the photosensitive sheet 23 along its longitudinal direction. The positioning holes are fitted into the tractor roller 24 sequentially. Power is transmitted to the tractor roller 24 via a clutch (not shown), and the photosensitive sheet 23 is fed out of the photosensitive sheet bucket 20 by the tractor roller 24 and is conveyed to the exposure plate 30.

The exposure plate 30 is disposed so as to be orthogonal to the light reflected by the mirror 18 in the optical system 10, and the mirror 18
The photosensitive sheet 23 is conveyed along the opposite surface. A heater 31 is attached to the surface of the exposure plate 30 opposite to the surface on which the photosensitive sheet 23 is conveyed, and the heater 31 keeps the exposure plate 30 at a predetermined temperature.
The photosensitive sheet 23 conveyed along 30 is set to a predetermined temperature. Thereby, the sensitivity of the photosensitive sheet 23 is maintained in a predetermined state.

The photosensitive sheet 23 conveyed along the exposure plate 30 is irradiated with the reflected light of the original 3 by the optical system 10. Thereby, the microcapsules on the photosensitive sheet 23 are selectively light-cured, and a latent image corresponding to the document image is formed on the photosensitive sheet 23.

Further, the light transmitting sheet projection unit 4 provided on the side surface of the copying machine main body 1 is in a state facing the exposure plate 30, and
When copying the image of the light-transmitting sheet, the light projected from the light-transmitting sheet projection unit 4 is directly conveyed along the exposure plate 30 by moving the mirror 18 in the optical system 10. The photosensitive sheet 23 is irradiated.

In the vicinity of the lower end of the exposure plate 30, a guide roller 32 and a buffer roller 33 are sequentially provided along the conveying direction of the photosensitive sheet 23. The guide roller 32 is positioned so as to slightly press the surface of the photosensitive sheet 23 conveyed along the exposure plate 30 on which the microcapsules are coated. The buffer roller 33 is opposed to the back surface of the photosensitive sheet 23, and is movable in the directions of arrows A and B orthogonal to the direction of conveyance of the photosensitive sheet 23 conveyed along the surface of the exposure plate 30. The photosensitive sheet 23 conveyed along the exposure plate 30 is wound around the guide roller 32, then is wound around the buffer roller 33, and its direction is directed to the photosensitive sheet bucket 20 side. Photosensitive sheet 23 wound around buffer roller 33
Is passed through the pressurizing device 50, and the photosensitive sheet bucket
It is wound around 20 winding shafts 25.

The buffer roller 33 is rotatable in both forward and reverse directions, is moved in the direction of arrow A from the home position described above, and is set to a drawn-out position 33a indicated by a broken line. By moving the buffer roller 33 to the drawing position 33a,
The photosensitive sheet 23 is pulled out by a predetermined length, and
Conveyed above.

The image receiving sheet 7 conveyed by the conveyance mechanism 40 is fed from the manual paper feed unit 5 or the paper feed cassette 6 provided on the side of the copying machine main body 1 to the pressure device 50 as the pressure developing unit. . The image receiving sheet 23 is supplied to the pressure device 50 by the transport mechanism 40 in synchronization with the photosensitive sheet 23 on which the latent image is formed by being exposed before being transported along the exposure plate 30. .

The pressing device 50 includes a large-diameter roller 51 and a small-diameter roller.
52 and two crown rollers 53 are provided. The superposed sheets 7 and 23 pass between the large-diameter roller 51 and the small-diameter roller 52 and are developed under pressure. This pressure developing force is applied by a crown roller 53 that is pressed against the small-diameter roller 52. In the pressurizing device 50,
The image receiving sheet 7 and the photosensitive sheet 23 on which the image has been exposed are pressed in a superimposed state, and as described above, only the uncured microcapsules that have not been cured by light are destroyed, and A coloring dye such as a leuco dye flows out to the image receiving sheet 7, and the coloring dye reacts with the developing material of the image receiving sheet 7 to form an image on the image receiving sheet 7. In this pressure development step, the photosensitive sheet 23
In order to prevent the occurrence of wrinkles due to looseness of the roller, the return speed of the buffer roller 33 to the home position is set to be equal to or less than 1/2 of the transport speed of the pressurizing device 50, and the speed difference is determined by the supply shaft 22. Absorption by the rotation of the, the moderate tension is applied to the photosensitive sheet 23,
Wrinkling of the photosensitive sheet 23 and the image receiving sheet 7 is prevented.

In this manner, the image receiving sheet 7 developed by the pressing device 50 is conveyed to the glossing device 60 via the attracting roller 55, and is pressed and heated by the glossing device 60, so that the image is glossed. Is given. The glossy image receiving sheet 7 is discharged onto the discharge tray 8 of the copying machine main body 1 by the discharge device 70 disposed on the discharge tray 8 side of the glossing device 60.

As shown in FIG. 1 (a), the buffer roller 33 pulls out the start position t 'of the photosensitive sheet 23 conveyed on the exposure plate 30 along the conveying direction with respect to the guide roller 32.
An exposure start position t (indicated by a broken line) separated from the (indicated by a dashed line) in a direction opposite to the pull-out direction indicated by an arrow B by an approach distance m; and a home position T (shown by a solid line) separated by n.

The operation of such an image forming apparatus will be described. The buffer roller 33 has a running distance m in the direction indicated by the arrow B with respect to the constant speed withdrawal start position t 'which is in a state of being juxtaposed with the guide roller 32 in the conveying direction of the photosensitive sheet 23 on the exposure plate 30.
And a home position further apart by a distance n. The photosensitive sheet 23 is wound around the winding shaft 25 in a state where tension is applied. However, after the pressure development is completed, the winding shaft 25 is slightly loosened due to rewinding. I have.

When the image forming apparatus is commanded in such a state, the buffer roller 33 is moved in the pull-out movement direction indicated by the arrow A. As shown in FIG. 1 (b), the buffer roller 33 is moved by the distance n and moved in the direction of arrow A to the exposure start position t, so that the looseness of the photosensitive sheet 23 is removed. The photosensitive sheet 23 is in a state where tension is applied. And the buffer roller 33
After the standby state is reached in the state in which the buffer roller 33 has reached the exposure start position t, the buffer roller 33 is moved again in the pull-out movement direction, and the exposure of the photosensitive sheet 23 to the image is started. When the buffer roller 33 moves by the approach distance m after passing the exposure start position t and is located at the constant speed withdrawal position t ′, the leading end of the exposure position on the photosensitive sheet 23 reaches the buffer roller 33. I do. When the buffer roller 33 reaches the constant-speed withdrawal position t ', the photosensitive sheet 23 is in a state in which tension is applied to the guide roller 32 and the buffer roller 33, and there is no looseness. Buffer roller at position t '
After the passage of 33, the photosensitive sheet 23 is pulled out at a constant speed by the buffer roller 33 moving at a constant speed in the pulling-out movement direction A, and is conveyed on the exposure plate 30 at a constant speed.

As described above, before the exposure of the photosensitive sheet 23 is started, the buffer roller 33 is moved by a predetermined distance n from the home position, whereby the looseness of the photosensitive sheet 23 is removed, and the photosensitive sheet 23 is not loosened. State. In such a state, exposure of the photosensitive sheet 23 is started. The tensioned photosensitive sheet 23 is also exposed to an image that is drawn out while the buffer roller 33 moves the approach distance m from the exposure start position t to a constant speed, but this portion is exposed to the image receiving sheet. 7 is a void portion where an image is not formed. And the photosensitive sheet
The image 23 is exposed while being transported at a constant speed by a buffer roller 33 moved at a constant speed.

As shown in FIG. 1 (c), the buffer roller 33
The image is exposed on the photosensitive sheet 23 that is moved at a predetermined speed until the predetermined draw position 33a is reached,
A latent image corresponding to the image is formed on the photosensitive sheet 23.

Thereafter, the buffer roller 33 is moved in the direction indicated by the arrow B, and is moved to the above-described exposure start position t. At this time, the photosensitive sheet 23 is sequentially wound and transported by the winding shaft 25, and during this time, the image receiving sheet 7 is superposed on the photosensitive sheet 23 and passed through the pressure developing unit 50. As a result, an image is formed on the image receiving sheet 7.

When such an image forming operation is completed, the buffer roller 33 is further moved in the direction indicated by the arrow B and is located at the home position T. In such a state, the image forming apparatus is in a standby state until the next image forming operation is instructed. When the image forming operation is instructed, the above-described operation is repeated.

(Effect of the Invention) In the image forming apparatus of the present invention, the buffer roller is moved from the home position to the exposure start position before the image is exposed on the photosensitive sheet, thereby removing the looseness of the photosensitive sheet. State. In such a state, the image is exposed while the photosensitive sheet is moved in a predetermined direction by the buffer roller. An image can be formed.

[Brief description of the drawings]

1A is an enlarged view of a main part of a copying machine which is an example of the image forming apparatus of the present invention, FIGS. 1B and 1C are explanatory views of the operation thereof, and FIG. FIGS. 3A to 3C are diagrams for explaining the operation of the main parts of a conventional copying machine. 7 ... image receiving sheet, 21 ... cartridge, 23 ... photosensitive sheet, 25 ... winding shaft, 30 ... exposure plate, 32 ... guide roller, 33 ... buffer roller, 40 ... transport mechanism, 50 ...
... Pressure developing device.

Claims (1)

(57) [Claims] An image is formed by exposing an image while conveying a photosensitive sheet coated with a photosensitive pressure-sensitive material, and superimposing the exposed photosensitive sheet on an image receiving sheet coated with a developing material to perform pressure development. In the apparatus, it is possible to reciprocate in a direction orthogonal to the conveying direction of the photosensitive sheet, and to draw out the photosensitive sheet by moving in one direction, comprising a buffer roller for conveying the photosensitive sheet at a constant speed, The buffer roller is separated from at least three positions on the moving path in one direction of the buffer roller, that is, a constant speed drawing position at which the photosensitive sheet reaches a constant speed, and a constant speed drawing position in a direction opposite to the one direction. The exposure start position and the home position, which passes through the exposure start position from the constant speed withdrawal position and is further away from this exposure start position, When the roller is positioned at the home position, the photosensitive sheet is wound up, and prior to exposure of an image, tension is applied to the photosensitive sheet by moving the buffer roller from the home position to the exposure start position to thereby apply a tension to the buffer sheet. An image forming apparatus which, when exposing an image, moves the buffer roller from the exposure start position to the constant speed withdrawal position when exposing an image, and then moves the buffer roller to pull out the photosensitive sheet.