JPH04158347A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is directed to forming an image on a photosensitive pressure sensitive sheet by performing slit exposure while winding up a roll of photosensitive pressure sensitive sheet onto a winding shaft. The present invention relates to a forming apparatus, and more particularly to an image forming apparatus having a feature of conveyance control of a photosensitive pressure-sensitive sheet.

(Prior Art) In this type of image forming apparatus, an inter-image area of a predetermined size is provided on a photosensitive pressure-sensitive sheet between a previous image exposed last time and a next image exposed this time.

By the way, an image forming apparatus using a photosensitive pressure-sensitive sheet, especially a sheet whose surface is coated with microcapsules encapsulating a photo-curable material and a color-forming material that hardens with light.
In an image forming apparatus that forms an image using a media sheet (hereinafter referred to as a media sheet), a method is used in which the inter-image area is exposed to light and the microcapsules in the inter-image area are hardened.

This is to prevent the microcapsules in the inter-image area from being destroyed and the coloring material from flowing out. That is, if the color-forming material in the ζ-image area flows out, the image forming paper and the pressure developing device will be contaminated.

Additionally, if the microcapsules in the inter-image area are not cured, the smoothness and rigidity of the media sheet will be unbalanced between the image forming area and the inter-image area, causing wrinkles in the media sheet in the pressure developing device. There are some problems such as

As a conventional example of an image forming apparatus equipped with means for exposing the inter-image area, for example, Japanese Patent Laid-Open No. 63-18986
In this conventional example, a light source for inter-image exposure is turned on while the media sheet is stopped, and the inter-image area is exposed to light to harden the microcapsules. In addition, a shutter is provided to prevent light from entering the image forming area, particularly the area where image formation will be performed.

(Problems to be Solved by the Invention) However, according to the above conventional example, since it is necessary to add a light source for inter-image exposure and a shutter, the configuration of the image forming apparatus becomes complicated and large, which leads to an increase in cost. ) There are some drawbacks.

The present invention solves these drawbacks of the prior art, has a simple and inexpensive structure, does not create an unexposed area between the previous image and the next image, and can be used for image forming paper and pressure developing devices. An object of the present invention is to provide an image forming apparatus that can eliminate problems such as contamination and wrinkles on a media sheet.

(Means for Solving the Problems) The present invention provides an image forming apparatus that forms an image on a photosensitive pressure sensitive sheet by performing slit exposure while winding up a roll of photosensitive pressure sensitive sheet around a winding shaft 3. , The reference inter-image distance between the previous image and the next image is set to the value for full-size copying, and the photosensitive pressure-sensitive sheet is transported, and when reduced copying is selected, the photosensitive pressure-sensitive sheet is The rewind amount is controlled so that it is smaller than the rewind amount during full-size copying corresponding to the reference image distance by the difference between the slit width during full-size copying and the slit width during reduced-size copying. When is selected, the amount of rewinding of the photosensitive pressure-sensitive sheet is controlled so that it is larger than the amount of rewinding during full-size copying by the difference between the slit width during enlarged copying and the slit width during full-size copying. , thereby achieving the above objective.

(Function) Under conditions where the inter-image area between the previous image and the next image is set to the value for full-size copying, in order to prevent unexposed areas from occurring in the inter-image area, photosensitive pressure sensitive The photosensitive pressure sensitive sheet may be rewound so that the rear end position of the previous image on the sheet becomes the exposure start position of the next image.

However, the length of the exposure light in the slit width direction is different during full-size copying and when reducing or enlarging copying.
The exposure start position is different. Therefore, if you rewind by the distance of the inter-image area, when copying the next image at the same size, there is no problem because the trailing edge position of the previous image matches the exposure start position of the next image, but the next image If an attempt is made to make a reduced copy of the previous image, the trailing edge position of the previous image will be located behind the exposure start position, causing a problem in which a portion of the previously fogged portion will be exposed again. On the other hand, if an attempt is made to enlarge and copy the next image, the trailing edge position of the previous image will be located in front of the exposure start position, resulting in an unexposed area between the previous image and the next image.

Therefore, in the present invention, when reducing or enlarging the next image, the amount of rewinding of the photosensitive pressure-sensitive sheet is adjusted by a predetermined amount compared to the value when copying at the same size. The rear end position of the previous image is matched with the exposure start position of the next image. Therefore, no unexposed area is generated between the previous image and the next image during reduction copying or enlargement copying.

(Example) The invention will now be described with reference to examples.

FIG. 1 is a front sectional view of a copying machine to which the present invention is applied.

This copying machine has a document mounting table 2 made of transparent glass provided on the top surface of a main body 1 of the copying machine.

A document 3 for forming a copy image is placed on the document table 2 . A light-transparent sheet projection section 4 is provided at the top of one side of the copying machine main body 1 for projecting an image formed on a light-transmissive sheet into the copying machine main body 1, and a manual feeder is provided below it. A paper section 5 and a paper feed cassette 6 are provided.

The paper feed cassette 6 stores an image receiving sheet 7 coated with, for example, an acidic developing material. This image receiving sheet 7 is
As will be described later, an image is formed on the image-receiving sheet 7 by overlapping it with the media sheet 23 and developing it under pressure. In addition, on the other side of the copying machine main body 1,
A paper ejection tray 8 is provided to eject the image receiving sheet 7 after the image has been formed thereon.

An optical system 10 is provided below the document table 2 . The optical system 10 includes a pair of irradiation lamps (light sources) 11 and 12 that irradiate light onto the original 3 on the original placing table 2, and reciprocates in the direction of arrow C and in the opposite direction. Both irradiation lamps 11
．． 12 and reflected from the original 3 is reflected in the direction opposite to the arrow C direction by the mirror 13, which moves together with the irradiation lamps 11 and 12. Next, the reflected light passes through a pair of reflective mirrors 15°1 in the mirror case 14.
6, the direction of movement is reversed. The inverted light passes through the lens unit 17, is reflected by the mirror 18, and is reflected through the slit 19 toward the exposure plate 3o provided approximately at the center of the copying machine body 1.

A cooling fan 65 for cooling the irradiation lamp 11.12 is attached to the optical system 10.

This cooling fan 65 reciprocates integrally with the irradiation lamps 1 and 12.

A packet 20 for media sheets is arranged below the mirror case 14. A cartridge 21 covered with a case made of light-shielding material is attached to the packet 20. The cartridge 21 has a roll-shaped media sheet 23 wound around an internal supply shaft 22 and stored therein.

The media sheet 23 is made of a light-sensitive and pressure-sensitive material, and has a particle size of about IO μm to 20 μm, in which a leuco dye and a photocuring substance are encapsulated on the surface of a light-reflective metal sheet such as aluminum.
It is made by coating a large number of microcapsules of m.

Positioning holes (not shown) are provided at both edges in the width direction of the media sheet 23 to be used when sequentially feeding out the media sheet 23 from the packet 20 along its longitudinal direction. The rollers 24 are fitted in sequence. Power is transmitted to drive the tractor roller 24 via a clutch (not shown), and the media sheet 23 is fed out by driving the tractor roller 24 and conveyed to the exposure plate 30 position.

The exposure plate 30 is arranged so as to be perpendicular to the light exposed from the mirror 18, and the media sheet 23 is conveyed along the surface facing the mirror 18.

A heater 31 is attached to the surface opposite to the conveying surface, and the exposure plate 30 is kept at a predetermined temperature by heating the heater 31, and the media sheet 23 conveyed at this position
is maintained at a predetermined temperature. As a result, media sheet 2
The sensitivity of 3 is maintained at a predetermined state.

When the media sheet 23 is exposed to light reflected from the original 3 by the optical system 10, the microcapsules on the media sheet 23'' are selectively photocured, and a latent image corresponding to the original image is formed on the media sheet 23. is formed.

Near the lower end of the exposure plate 30, a guide roller 32 and a buffer roller 33 are provided in this order in the transport area of the media sheet 23. The buffer roller 33 is movable from a home position opposite the back surface of the media sheet 23 in six directions of arrows perpendicular to the exposure plate 3o.

The media sheet 23 conveyed along the exposure plate 3o is
It is wound around the buffer roller 33 and its direction is directed toward the packet 20 side. The media sheet 23 wound around the buffer roller 33 passes through the pressure developing device 50 and is wound around the winding shaft 25 of the cartridge 21 .

The buffer roller 33 is rotatable in both forward and reverse directions, and is moved in the six directions of arrows from the home position described above to a pull-out position 33a shown by a broken line. When the buffer roller 33 is moved to this pull-out position 33a,
The media sheet 23 is pulled out by a predetermined length.

At the position of the pressure developing device 50, the above-mentioned manual paper feed section 5 is installed.
Alternatively, the image receiving sheet 7 is fed from the paper feed cassette 6 via the conveyance mechanism 40. This feeding is performed in synchronization with the latent image formed on the media sheet 23 by exposure from the mirror 18.

In the pressure developing device 50, the image-receiving sheet 7 and the media sheet 23 on which the latent image has been formed are pressed in a superimposed state, and as described above, only the uncured microcapsules that have not been cured by light are destroyed. . As a result, the coloring dye such as the heloco dye on the image receiving sheet 7 flows out from the media sheet 23, the coloring dye reacts with the developing material of the image receiving sheet 7, and an image corresponding to the original image is formed on the image receiving sheet 7.

The image receiving sheet 7 developed by the pressure developing device 50 is conveyed to a glossing device 60, where it is heated and gloss is imparted to the image. The glossy image receiving sheet 7 is
The pressure is discharged onto the paper discharge tray 8.

The outline of the image forming process in this copying machine has been explained above, but in this copying machine, the media sheet 23
The media sheet 23 is conveyed so that no unexposed area occurs between the previous image and the next image, that is, the position of the rear end of the previous image becomes the exposure start position of the next image. is controlled. The details will be explained below.

FIG. 2 shows a control system that controls the conveyance of the media sheet 23. A main motor drive circuit 71 drives and controls the main motor 72 based on a drive command given from the CPU 70, and conveys and rewinds the media sheet 23. be exposed.

The conveyance of the Mechia sheet 23 is performed by a tractor roller 24 connected to the main motor 72 via a speed reduction device. On the other hand, the media sheet 23 is rewound by controlling the amount of rotation of the supply shaft 22 connected to the main motor 72 via a speed reduction device. Note that during rewinding, the tractor roller 24 is in a free state.

The amount by which the media sheet 23 is rewound is determined by the copy magnification. That is, in this copying machine, when the media sheet 23 is conveyed with the reference inter-image distance set to the value used for full-size copying, and when forming the next image during full-size copying, only the image-to-image distance is set. The media sheet 23 is rewound. On the other hand, when forming the next image by reduced copying or enlarged copying, the media sheet 23 is rewound by a value obtained by adding a certain correction to the rewound amount during the same-size copying.

FIG. 3 is a diagram for explaining the specific amount of rewinding of the media sheet 23 during reduction copying and enlargement copying. In the figure, the arrow indicates the conveyance direction of the media sheet 23, and the distance a (=S, -3,) is the length in the width direction of the slit 19 of the exposure light during full-size copying (hereinafter referred to as slit width), and the distance b(=S2~Ss)
is the slit width and distance c (-33 to
S6) indicates the slit width at the time of enlarged copying. Further, S7 indicates the rear end position of the exposed portion of the previous image at the end of development. Therefore, in the figure S l + 32 +
S3 corresponds to the exposure start position of the next image during full-size copying, reduced copying, and enlarged copying, respectively.

Here, in the present invention, since the media sheet 23 is conveyed with the reference inter-image distance set to the value at the time of 1x copying, when the next image is exposed for 1x copying, the exposure area at the end of development is Exposure is performed by rewinding the rear end S7 to the exposure start position S1 for the next image. Therefore, the rear end S7 of the exposure section of the previous image coincides with the exposure start position for the next image,
No unexposed area is generated between the previous image and the next image.

On the other hand, in order to eliminate the unexposed part during reduction copying, it is sufficient to rewind the film so that the rear end S7 of the exposed part coincides with the exposure start position S2. Therefore, the amount of unwinding in this case is
As is clear from FIG. 3, it is sufficient to set the rewind amount to a value that is (a-b)/2 smaller than the rewind amount (S, ˜S,) during the same-size copy.

Furthermore, in order to eliminate unexposed areas during enlarged copying, it is sufficient to rewind the film so that the rear end S of the exposed area coincides with the exposure start position S3. Therefore, the rewind amount in this case is (
It is sufficient to set the value to a larger value by c-a)/2.

FIG. 4 is a flowchart showing the control procedure of the CPU 70 in such conveyance control. The CPU 70 first determines whether the copy switch Sl (see FIG. 2) has been turned on in step n1, and determines whether the copy switch Sl (see FIG. 2) has been turned on. When this is confirmed, it is then determined whether the same size copy has been selected from the copy magnification selection switch S2 (see Figure 2) (n2).
.

After confirming that the same size copy is selected, proceed to step n.
Execute the copy execution subroutine shown in 3, and then
Returning to step n1, if the copy switch S1 is in the ON state, the determination in step n2 is made again, and if the copy switch S1 is in the ON state, this control program is ended.

On the other hand, if it is determined in step n2 that the copy is not the same size, then in step n4 it is determined whether or not reduced copy is selected, and when it is confirmed that reduced copy is selected, the slit width that is manually set in advance is a, b,
(a-b)/2 is calculated according to the data regarding c (n5). Then, in step n5, according to the calculation result,
Issue a rewind command signal to the main motor drive circuit 71,
The media sheet 23 is rewound by (31~St) (ab)/2 via the main motor 72 and the supply shaft 22 (η6), and the copy execution process of step n3 is performed.

Further, if reduced copying is not selected in step n4, that is, enlarged copying is selected, step n4
Execute the calculation of (c-a)/2 in 7 and according to the calculation result,
Issue a rewind command signal to the main motor drive circuit 71,
Media sheet 23 (S, ~S,) + (c-a)
Rewind by /2.

Then, the copy execution process of step n3 is performed.

(Effects of the Invention) According to the present invention described above, regardless of changes in copy magnification,
Since the rear end of the previous image and the exposure start position of the next image can be matched, an unexposed area will not occur between the previous image and the next image. Therefore, the color forming material does not flow out and contaminate the image forming paper or the pressure developing device. Further, problems such as wrinkles occurring in the media sheet in the pressure developing device section do not occur.

Furthermore, since there is no need to provide an inter-image exposure light source or a shutter, there is an advantage that a simple and inexpensive device configuration can be realized.

FIG. 1 is a front sectional view of a copying machine to which the present invention is applied, and FIG. 2 is a drawing showing a control system that controls the conveyance of media sheets.
FIG. 3 is a drawing for explaining the specific amount of rewinding of the media sheet during reduction copying and enlargement copying,
FIG. 4 is a flowchart showing the control procedure of the CPU in transport control.

1... Copying machine main body, 7... Image receiving sheet, 1o...
Optical system, 19... Slit, 22... Supply shaft, 23
...Media sheet, 30...Exposure plate, 70...
CPU, 72...Main motor.

that's all

Claims (1)

[Scope of Claims] 1. In an image forming apparatus that forms an image on a roll-shaped photosensitive pressure-sensitive sheet by performing slit exposure while winding the photosensitive pressure-sensitive sheet around a winding shaft, the previous image and the next image are provided. The photosensitive pressure-sensitive sheet is transported with the reference inter-image distance set to the value for full-size copying, and when reduced copying is selected, the amount of rewinding of the photosensitive pressure-sensitive sheet is set to the value for full-size copying. The rewind amount is controlled to be smaller than the rewind amount during full-size copying, which corresponds to the reference inter-image distance, by the difference between the slit width at the time of copying and the slit width during reduced copying. An image forming apparatus in which the amount of rewinding of a photosensitive pressure-sensitive sheet is controlled to be larger than the amount of rewinding during full-size copying by the difference between the slit width during enlarged copying and the slit width during full-size copying.