JPH04152341A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a recording medium from slacking by releasing the nip of a pair of rollers during pressure development. CONSTITUTION:A nip roller 135 is brought into pressurized-contact with a pressure roller 71 by the rotation of the eccentric cam 136 of a pressure development device 70, and a fixing roller 56 is pressed against the left edge of an exposure pedestal 52. The photosensitive recording medium 50 is sent while being pressurized with a developer sheet 60 firmly, and color images corresponding to latent images on the medium 50 is developed on the sheet 60. When the cam 136 rotates due to the rotation of the roller 71, and the roller 135 comes into pressurized-contact with the roller 71, a pressure roller nip detecting sensor 131 detects it. Immediately before rear end of the sheet 60 passes through the rollers 71 and 135, the cam 136 is caused to rotate to separate the roller 135 from the roller 71. Thus, the nip is released and the releasing is detected with the sensor 131. The energizing of a solenoid is interrupted and a driving roller 57 is caused to nip. Thus, the medium 50 is prevented from slacking.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image forming apparatus that forms an image by exposing a photosensitive recording medium to light, overlapping it with a color developer, and performing pressure development.

[Prior Art] Conventionally, this type of device has been provided with a pair of rollers for conveying the photosensitive recording medium between a pressure developing device and a winding core that winds up the photosensitive recording medium after being subjected to pressure development. A friction clutch was interposed between the winding core and the drive source. In this device, the speed of the winding core is set faster than the conveyance speed of the pair of rollers, and the speed difference is eliminated by a friction clutch.

[Problem to be solved by the invention] However, although the speed difference between the roller pair and the winding core after pressure development is eliminated by a friction clutch, the conveyance speed of the photosensitive recording medium during pressure development is controlled by the pressure development device. Therefore, due to the speed difference between the pressure developing roller and the pair of rollers that transport the photosensitive recording medium, if the speed of the pair of rollers is high, the photosensitive recording medium is pulled, and the pair of rollers slips. A considerable load is placed on the pair of rollers, and if the speed of the pressure developing roller is high, sagging occurs between the photosensitive recording medium or the pressure developing roller and the pair of rollers, which has an adverse effect on the separation of color developer paper, etc. There was a case.

The present invention has been made to solve the above-mentioned problems, and by making it possible to freely open and close the nip between the pair of rollers at the rear of the pressure developing device, the nip between the pair of rollers can be opened during pressure development. , the conveyance of the photosensitive recording medium is completely controlled by the pressure developing roller, thereby preventing the load on the roller pair due to the photosensitive recording medium being pulled and the pair of rollers slipping; It is an object of the present invention to provide an image forming apparatus that can prevent a roller from sagging between a pair of rollers, which would adversely affect the separation of color developer paper.

[Means for Solving the Problems] In order to achieve this object, the image forming apparatus of the present invention includes a winding means for winding up the photosensitive recording medium after pressure development, and a winding means between the pressure developing device and the winding means. A pair of rollers capable of opening a nip for conveying a photosensitive recording medium, a detection means for detecting opening/closing of a nip of a pressure roller of a pressure developing device, and a pair of rollers capable of opening and closing a nip of a pressure roller of a pressure developing device; and a control means for controlling the nip to open when the pressure developing device is pressurizing the photosensitive recording medium.

[Function] In the image forming apparatus of the present invention having the above configuration, the detection means detects the opening and closing of the nip of the pressure roller of the pressure developing device, and the control means detects whether the nip of the pressure roller of the pressure developing device is nipped. When the nip of the roller pair is opened and the pressure developing roller is not nipped, the pair of rollers are nipped. In either case, the tension and sagging of the photosensitive recording medium caused by the speed difference between the pressure developing device and the pair of rollers is eliminated by the winding means that winds the photosensitive recording medium through a friction clutch.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a monochrome laser printer 1 and a color image recording device 20 in a combined arrangement.

First, the monochrome laser printer 1 is mounted on top of the color image recording device 20. As shown in FIG. In the laser printer 1, a polygon scanner 2 irradiates laser light onto a charged photoreceptor 3, thereby drawing an electrostatic latent image. The photoreceptor 3 on which the electrostatic latent image has been formed is developed by a developing device 4, and the toner image is transferred onto plain paper or an OHP sheet fed from a paper feed cassette 5, and fixed by a fixing device 6. Typically, the monochrome laser printer 1 records data transmitted from a host computer.

The output from the laser printer 1 is sent to the paper path switching unit 10.
If a black and white image is required, it is fed to the monochrome output tray 11 or automatic document feeder (hereinafter referred to as ADF) tray 12; if a color image is required, it is fed to the ADF.
) After being sent to the ray 12, the color image recording device 20
taken inside. The sheets sent to the ADF tray 12 are taken one by one into the color image recording device 20 by the ADF paper feed roller 13, and a set of three sheets of black and white printed paper is printed from the laser printer 1. The mask original plate 15 (15) of the color image recording device 20
R215G, 15B).

Next, the configuration of the color image recording device 20 will be explained.

A positioning device 31 is located at the bottom of the main body of the color image recording device 20, and the ADF tray 12 and the positioning device 31 are connected by a mask original transport path 21.

On both the left and right sides of the positioning device 31, there are pairs of rollers 22, 23, 24, 25, 26, 27, whose rotational direction can be controlled.
Gates 28 and 29 and a mask original storage section 102 are arranged.

In the middle of the mask original transport path 21, a pair of recurler rollers 101 is arranged to remove curls from the mask original 15 discharged from the laser printer 1. roller vs 2
On the outside of 6.27, there is a mask original discharge tray 30 for discharging the used mask original 15.

The positioning device 31 includes a sensor (not shown), a pair of rollers 3233 placed near both left and right ends, a glass plate 34 placed between them, and the like.

An exposure device 41 is arranged below the alignment device 31, and this exposure device 41 is connected to the alignment device 3.
It is movable in the left and right direction along 1. The exposure device 4
1 includes a linear white light source (hereinafter referred to as a lamp) 42, a reflecting plate 43 that reflects light from the lamp 42, a red filter 44R, a green filter 44G, and a blue filter 44.
It is composed of a filter unit 44 consisting of B.

The photosensitive recording medium 50 is, for example, disclosed in Japanese Patent Application Laid-Open No. 62-14304.
The main material is a photocurable resin using a photopolymerization initiator known in Publication No. 4, and the photocurable resin is cured by light of red, green and blue wavelengths, and cyan, magenta, and yellow. Microcapsules containing each dye precursor are coated on a base sheet. The photosensitive recording medium 50 is housed in a cartridge 51 so as not to be exposed to light. The photosensitive recording medium 50 is routed from inside the cartridge 51, passing between the glass plate 34 and the exposure table 52, passing through a buffer 551, a separating roller 64, a pressure developing device 70, and a driving roller 57, and then reaching the winding roller 54. The exposure table 52 receives the mask original 15 processed by the cam 53 and conveyed onto the glass plate 34.
and the photosensitive recording medium 50 are brought into close contact with each other.

Further, the fixed roller 56 is pressed against the left end of the exposure table 52 when the exposure table 52 is lowered to a predetermined position.
The photosensitive recording medium 50 is placed on the exposure table 5 during exposure of the mask original 15.
It is arranged to be fixed at 2. Further, the drive roller 57 includes two drive rollers 57a as shown in FIG.
, 57b, and the drive roller 57a has a holding member 131 that is rotatable around a fixed shaft 132.
is maintained. The holding member 13 is biased by a spring member 133 so that the drive roller 57a is always pressed against the drive roller 57b. Further, the holding member 131 is configured to be able to open the nip between the roller pair 57 by operating the solenoid 134 against the force of the spring member 33. Further, a well-known friction clutch is interposed between the take-up roller 54 and the take-up core drive device 128, and absorbs errors in the conveyance speed of the drive roller 57 and the pressure roller 71. Further, the pressure developing device 70 is configured such that the nip roller 135 is nipped with the pressure roller 71 by rotating the eccentric cam 136, and the sensor 131 detects whether or not the pressure roller 71 is nipped. be able to.

The developer sheet 60 is constructed by coating a base paper with a developer described in, for example, Japanese Patent Laid-Open No. 58-88739, and is placed in the cassette 61 so that the developer-coated surface faces downward. It is set.

At the top of the cassette 61, a suction cup 62 for feeding the developer sheets 60 one by one is arranged.

The pressure developing device 70 is composed of a photosensitive recording medium 50 on which a latent image has been formed by exposure, and a pair of pressure rollers 71 for overlapping a color developer sheet 60 and developing it under pressure.

The heat fixing device 80 is constructed between a casing 83 containing a heater 81 and an impeller 82 in the upper part, rubber rollers 84, 85, 86 for conveying the color developer sheet 60 in the lower part, and rollers 87 and 88. A paper ejection tray 63 is attached to the outside of the heat fixing device 80.

FIG. 3 shows a control device of this image forming apparatus.

The main control device is the CPU 122. RAM123゜ROM1
24 and bus 125.
It is 126.

The microcomputer 126 is further connected to a winding core drive device 128 and a solenoid 134 via a winding core control circuit 127 and a solenoid control circuit 129, respectively. A sensor 131 for detecting the nip state of the pressure developing device 70 is also connected to the bus 125. The winding core 138 carries the photosensitive recording medium 50 after pressure development.
The solenoid 134 is for opening the nip of the drive roller 57.

In the apparatus configured as described above, the operation when obtaining a plurality of color images from one set of mask originals will be described below.

First, a mask original plate 15R for red is created using the monochrome laser printer 1. This mask original version 15R is
In order to harden the microcapsules containing a cyan dye precursor among the microcapsules coated on the photosensitive recording medium 50, this mask original plate has toner as a light-shielding image placed on other parts. At this time, the mask original 15R outputted from the monochrome laser printer 1 is sent to the ADF tray 12 and fed into the color image recording device 20 by the ADF paper feed roller 13. Color image recording device 20
The mask original 15R fed inside passes through the mask original transport path 21 and is sent to the positioning device 31 by the roller pair 24, 22. On the way, the curl of the mask master plate 15R is corrected by the curler roller 101. At this time,
Gate 28 is located at the solid line position.

Next, the alignment device 31 transports the mask original 15R to an appropriate exposure position by the roller pair 32, and then uses a drive source (not shown) to read the alignment mark printed on the mask original 15R with a sensor. move it into place.

Immediately before alignment, the exposure table 52 is lowered to a predetermined position by a cam 53, and a fixed roller 56 is pressed against the left end of the exposure table 52 to fix the photosensitive recording medium 50 to the exposure table 52. After the alignment is completed, the exposure table 52 is further lowered by the cam 53 and comes into contact with the glass plate 34 of the alignment device 31, and the mask original 15R and the photosensitive recording medium 50 are exposed.
and bring them into close contact.

When the exposure table 52 comes into close contact with the alignment device 31, the lamp 4
2 lights up, and the exposure device 41 performs scanning exposure in the direction of the arrow in order to expose the photosensitive recording medium 50 with red light via the mask original plate 15R via the red filter 44R. When the exposure is completed, The lamp 42 is turned off, and the exposure device 41 moves back in the direction of arrow B. At this time, the exposure device 41
The filter unit 44 is moved by a drive source (not shown), and a green filter 44G is positioned above the lamp 42.

While the exposure device 41 moves backward, the exposure table 52 is raised by the rotation of the cam 53, and the photosensitive recording medium 50 is separated from the alignment device 31 and the mask original 15R. At this time, pack tension is applied to the photosensitive recording medium 50 at the center of rotation of the roll of the photosensitive recording medium 50 in the cartridge 51, and when the exposure table 52 descends,
A length corresponding to the amount of descent of the exposure table 52 is pulled out from the storage cartridge 51, and the exposure table 52 is pulled out after exposure is completed.
2 rises, the photosensitive recording medium 50 is rewound in a direction to take up the slack.

Even after the exposure of the red mask master plate 15R is completed, the exposure table 52 only rises to a predetermined position, and the photosensitive recording medium 50 is moved to the exposure table 52 by a fixed roller 56 pressed against the left end of the exposure table 52. remains fixed.

Next, the green mask original 15G created by the monochrome laser printer 1 is placed in the ADF tray 12,
When the sheet passes through the F paper feed roller 13, recurler roller 101, and mask original transport path 21, and reaches just before the roller pair 24,
Roller pair 22, 24° 25.27. Positioning device 31
The pair of rollers 32 and 33 are rotated in the direction of conveying the mask original 15R to the right, and at the same time the mask original 15R is sent out from the alignment device 31, the mask original 15G is conveyed to the exposure position and stopped. At this time, gate 28.
29 is located at the position of the solid line, and is the exposed mask original plate 15.
R is held between the pair of rollers 27 and with its rear end passing through the gate 29, by stopping the rotation of the pair of rollers 27.

The mask original 15G guided by the alignment device 31 is aligned with the photosensitive recording medium 50 in the same manner as the mask original 15R, and then the exposure table 52 is lowered to align the mask original 15G with the photosensitive recording medium 50. Being brought into close contact. After that, the lamp 42 is turned on, and the green filter 44G
Exposure to green light is performed through the . After the exposure is completed, the exposure table 52 is raised to a predetermined position. The exposure device 41 is moved back to the original position, and the lamp 42
The filter unit 44 is moved so that the blue filter 44B is positioned above the blue filter 44B.

Next, the blue mask original 15B created by the monochrome laser printer 1 is similarly fed to the color image recording device 20, and is conveyed just before the roller pair 24, 25, 26. and alignment device 3
The pair of rollers 3233 of 1 are rotated in the direction of conveying the mask original 15G to the right, and the mask original 15G is sent out from the alignment device 31 and the mask original 15B is rotated.
is transported to the exposure position and stopped. At this time, gate 28
is located at the position shown by the solid line, and the two gates are located at the position shown by the broken line, and the exposed mask original 15G is held between the pair of rollers 26 and passes through the rear end of the gate 29, when the pair of rollers 27 rotates. It is maintained by stopping it.

The mask original 15B guided by the alignment device 31 is brought into close contact with the photosensitive recording medium 50 by a similar operation. The photosensitive recording medium 50 is exposed to blue light through the mask original 15B.

Through the above operations, a latent image of a desired color image is recorded on the photosensitive recording medium 50.

Next, the exposure table 52 is raised to the initial position, the fixed roller 56 is separated from the left end of the exposure table 52, and the buffer 55 is moved in the direction of arrow E, thereby removing the unexposed portion of the photosensitive recording medium 50. is pulled out from inside the cartridge 51 below the exposure table 52. Drive roller 57
The photosensitive recording medium 50 is conveyed and stopped when the leading edge of the latent image reaches the pressure roller 71 of the pressure developing device 70.

In synchronization with the movement of the photosensitive recording medium 50, the developer sheet 60 is fed out from the cassette 61 by a suction cup 62 until the tip of the developer sheet 60 corresponds to the tip of the latent image on the photosensitive recording medium 50. After being transported, it stops.

Next, the process of pressure developing the latent image will be described with reference to the flowchart of FIG.

In the pressure developing device 70, an eccentric cam 135 of the pressure developing device 70 is rotated by a drive device (not shown), and the nip roller 131 is pressed against the pressure roller 7. At this time, by lowering the exposure table 52 to a predetermined position again, the fixed roller 56 is pressed against the left end of the exposure table 52, and the photosensitive recording medium 50 is fixed to the exposure table 52. The photosensitive recording medium 50 is conveyed under pressure while being overlapped with the color developer sheet 60, and the uncured microcapsules on the photosensitive recording medium 50 are destroyed by the pressure, and the photosensitive recording medium 50 is
A color image corresponding to the upper latent image is developed on the developer sheet 60.

By rotating the pressure roller 71 of the pressure developing device 70 in the direction of the arrow, the buffer 55 is moved in the direction of the arrow F. In this case, in step 1 in the flowchart of FIG. 2 (hereinafter referred to as S1; the same applies to other steps), when the eccentric cam 135 rotates and the pressure roller 71 and nip roller 136 are brought into pressure contact,
Pressure roller nip detection sensor 131 detects this.

Next, by operating the solenoid 134 in S2, the holding member 131 rotates, and the nip of the drive roller 57 is released (s2). As a result, the photosensitive recording medium 50 is conveyed under the conveyance force of the pressure roller 71 and the nip roller 135.

The color developer sheet 60 is peeled off from the photosensitive recording medium 50 by a separation roller 64 and guided toward a heat fixing device 80 . Further, just before the rear end of the color developer sheet 60 completely passes through the pressure roller 71 and the nip roller 135, the eccentric cam 135 is rotated again by a drive source (not shown), and the nip roller 135 is separated from the pressure roller 71. Then, the nip is opened. At this time, the pressure roller nip detection sensor 131 again detects whether the nip is opened (Sl). As soon as it is detected that the nip is opened, the power to the solenoid 134 is cut off, and the drive roller 57 held by the holding member 131
a rotates around the fixed shaft 132 by the force of the spring member 133, and the drive roller 57 is nipped (S3).

In this case, the photosensitive recording medium 50 is conveyed under the control of the drive roller 57.

In the heat fixing device 80, the color developer sheet 60 is heated by a heater 81 and heated by air circulating in a casing 83 by an impeller 82, thereby promoting color development of a color image. At the same time, the binder polymer (fixing resin) for fixing the color developing medium to the base paper of the color developer sheet 60 is thermally melted and the surface becomes smooth, giving the surface of the color developer sheet 60 an appropriate level of gloss. It will be done. The color developer sheet 60 that has been subjected to color development and gloss treatment is discharged to a paper discharge tray 63.

During the above-described series of development and coloring/glossy processing, the photosensitive recording medium 50 is held and fixed between the exposure table 52 and the fixed roller 56. Therefore, while the development processing for one screen is being performed, the next exposure point is It is possible to perform exposure processing on the latent image of a color image.

When performing exposure processing for the latent image of the second color image, first, the mask original 15B at the exposure position is sent out to the left, and the mask original 1.
A pair of rollers 2 is used to feed 5R to the alignment device 31.
4.22. 25, 27 and the roller pair 32, 33 of the positioning device 31 are rotated so as to convey the mask original 15R to the left. At this time, the gates 28 and 29 are located at the positions indicated by solid lines. The mask original plate 15B has a pair of rollers 24
The rotation of the pair of rollers 24 is stopped and held at the position where the rear end passes through the gate 28.

The mask original 15R sent to the alignment device 31 is aligned and brought into close contact with the photosensitive recording medium 50. The photosensitive recording medium 50 is exposed to red light through the mask original 15R.

Next, the mask original 15R at the exposure position is sent to the left, and the mask original 15G held at the position of the roller pair 26 is aligned with the roller pairs 22, 23, 25, and 26 in order to be sent to the alignment device 31. The pair of rollers 32 and 33 of the device 31 are rotated so as to convey the mask original 15G to the left. At this time, the gates 28 and 29 are located at the positions indicated by broken lines. Mask original plate 15R has roller pair 23
It is held by stopping the rotation of the pair of rollers 23 at a position where the rear end passes through the gate 28.

The mask original 15G sent to the alignment device 31 is aligned and brought into close contact with the photosensitive recording medium 50. The photosensitive recording medium 50 is exposed to green light through the mask original 15G.

Next, the mask original 15G at the exposure position is sent out to the right, and the same operation is performed to send the mask original 15B held at the position of the roller pair 24 to the alignment device 31, so that the color is printed on the photosensitive recording medium 50. A latent image of the image is formed to form a color image on the developer sheet 60.

By repeating the same operation, one set of mask originals 1
5, a predetermined number of color images can be output.

After obtaining the required number of color images from the same mask original 15, each mask original 15 is discharged from the roller pair 27 or the roller pair 26 to the paper discharge tray 30.

In addition, if the next mask original 15 is output from the monochrome laser printer 1 while a series of color images are being exposed, it is temporarily stored in the ADF tray 12 and the exposure of the previous set is completed. Then, the ADF paper feed roller 13 feeds the paper sheets one by one into the color image recording apparatus 20.

Furthermore, when reusing a mask original output from another monochrome laser printer or a previously used mask original, the mask original can be input by setting it on the ADF tray 12.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the nip between the pair of rollers is opened during pressure development in the pressure developing device, so that the conveyance speed of the photosensitive recording medium is increased. A considerable load is placed on the roller caused by the speed difference between the pressure opening and the roller pair of the pressure developing device caused by the pressure developing device being controlled by the pressure developing device during development, and the separation of the color developing paper due to the sagging of the photosensitive recording medium. It is possible to prevent negative effects on

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an image forming apparatus showing the configuration of the present invention, FIG. 2 is a control flowchart, FIG. 3 is a block diagram showing the electrical configuration, and FIG. 4 is a perspective view showing the drive roller. It is. In the figure, 50 is a photosensitive recording medium, 57 is a drive roller, 70 is a pressure developing device, 71 is a pressure roller, 131 is a sensor,
135 is a nip roller.

Claims (1)

[Scope of Claims] 1. In an image recording apparatus that exposes a photosensitive recording medium to light and performs pressure development while overlapping it with a color developer sheet to record an image, a roll for winding up the photosensitive recording medium after pressure development. a pair of rollers capable of opening a nip for conveying a photosensitive recording medium between the pressure developing device and the winding device; a detection device for detecting opening/closing of the nip of the pressure roller of the pressure developing device; control means for controlling the pair of rollers to nip when the pressure developing device is not pressurizing the photosensitive recording medium and to open the nip when the pressure developing device is pressurizing the photosensitive recording medium. An image forming apparatus characterized by: