JPH03118537A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the generation of uneven density in an output image by boosting the pressure value of pressure development in response to the rise in the carrying speed of a light- and pressure-sensitive recording material after the final stage of a series of exposure process is completed. CONSTITUTION:When a lamp driving circuit 11 lights a lamp 10 to continue lighting for a prescribed length of time, a pressuring motor driver 8 rotates and drives a pressure motor 7 at the timing t12 to start pressure development under a pressure value P1. When the pressure development starts, the carrying speed is S1 as it is, and the lamp 10 is put off at the timing t13 to terminate exposure. At the timing t13, the carrying speed S1 is accelerated to S2, and simultaneously the pressure value P1 is boosted to P2. The carrying speed S2 is continued until copying ends at the timing t15. The instant that the carrying speed is accelerated, the pressure value is boosted; therefore, pressure per unit length of the roll-like recording medium is never weakened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that exposes an image to a light-sensitive pressure-sensitive recording medium and, after exposure, performs pressure development on a color developing medium to obtain a copy image.

[Conventional technology]

Recently, as a color copying machine (image forming device), an original image is exposed to a roll-shaped recording medium (microcapsule paper), and a color developer is applied to the exposed microcapsule paper and a support such as plain paper. The color image on the exposed microcapsule paper is transferred onto the developer paper by this pressure developer, and the color image after pressure development is sent to a heat fixing device where the color image is transferred onto the developer paper. A type of image capture system is emerging.

The detailed configuration of such a color copying machine will be explained with reference to FIG.

As shown in FIG. 5, a movable original platen glass 52 and an original platen cover 53 are provided on the top plate of the copying machine 51, and an original 54 is placed on the original platen glass 52 with the original surface facing downward. It is set with the camera facing the camera. A light source 55 made of a 1\logen lamp or the like is disposed on the top of the copying machine 51. The light emitted from the light source 55 irradiates the light in a line toward the document table glass 52 through a slit hole provided on the top surface of the body, and the irradiated light is transmitted through the transparent document table glass 52. ing. That is, the light source 55
The light emitted from the original plate 52 is reflected by the original 54 set on the original platen glass 52. By moving the document platen glass 52, exposure scanning of the document 54 is performed. Manuscript 5
The light reflected from 4 passes through a filter 56 for adjusting the color tone of the copied image and enters a projection lens 57, and the light projected by this lens 57 passes through a pair of reflection mirrors 58.
．． Microcapsule paper 6, which is a photosensitive and pressure sensitive recording medium, is changed direction by 59 and is conveyed along an exposure table 60.
The image is formed on the exposure surface of 1. Said reflective mirror 58.59
is attached to a mirror mounting plate, and the optical path length and focus are adjusted by finely adjusting the mounting position of the mirror mounting plate.

On the other hand, the microcapsule paper 61 is
A is housed in a removable cartridge 62b in the main body of the apparatus in a wound state.

An empty sensor 206 serving as movement state detection means is provided near the outlet for the microcapsule paper 61 in the cartridge 62b. The empty sensor 206 detects whether or not the remaining amount of the microcapsule paper 61 wound around the cartridge shaft 62a has become zero, and outputs a predetermined detection signal. A league part of a predetermined length is formed at one end of the microcapsule paper 61, and a roller 72 is opened and closed by a feed roller 64a1, guide roller 64b10-ra movement motor (not shown),
The sheet passes through the dancer roller 74, the feed roller 64c, the pressure developing device 63, the separation mechanism 64d, and a roller opened and closed by a roller movement motor (not shown), and then reaches the take-up shaft 65 to which the automatic paper passing lever 217 is attached. ing. That is, the microcapsule paper 61 coming out from the lower part of the cartridge 62b is guided by the feed roller 64a1 and the guide roller 64b, passes through the lower surface of the exposure table 60, passes through the roller 72 and the dancer roller 74, and is supplied to the pressure developing device 63. be done. Further, the microcapsule paper 61 that has passed through the pressure developing device 63 is guided to a separating mechanism 64d and a roller 73, and then wound onto a winding shaft 65. Note that the unexposed microcapsule paper 61 after leaving the cartridge 62b is maintained in an unexposed state by the light shielding cover 62c.

Further, the conveying speed of the microcapsule paper 61 is controlled to match a predetermined speed, that is, the moving speed of the document table glass 52. Therefore, latent images of predetermined lines of the original document 54 are sequentially formed on the microcapsule paper 61 as it passes through the exposure table 60.

Below the pressure developing device 63, a paper feed cassette 67 constituting a paper feed device is detachably attached to the main body of the copying machine. The paper feed cassette 67 accommodates cut paper-like color developer paper (color developer medium) 66, and is provided with a suction cup type paper feed mechanism 68 that sucks the paper using negative pressure suction. The developer paper 66 is taken out one by one by a paper feed mechanism 68 and sent to a feed roller 69a.
1 pinch roller 69b, and the developing paper roller 6
After the leading end is aligned by 9c, 69d and the resist gate 69e, it is carried into the pressure developing device 63.

In this way, the pressure developing device 63 contains the microcapsule paper 6.
1 and color developer paper 66 are supplied in an integral state in close contact with each other, and the microcapsule surface of the microcapsule paper 61 on which the latent image is formed and the color developer coated surface of the color developer paper 66 are brought into contact with each other on the inside. As a result, it is sandwiched between the small diameter roller 63a and the backup roller 63b, and pressure is applied to it. This pressure destroys the unexposed microcapsules and forms a color image on the color developing paper 66.

After the microcapsule paper 61 and the color developer paper 66 that have come out of the pressure developing device 63 are separated by a separation mechanism 64d, the color development of the color developer paper 66 is promoted by the heat roller 70a of the heat fixing device 70 to form an image. , and is carried out to the paper discharge tray 71 by paper discharge rollers. Note that the separated microcapsule paper 61 passes through a roller 73 and is wound up on a winding shaft 65.

In the copying machine configured as described above, the interrelationship between the timing of exposure and pressure development, the conveyance speed, and the magnitude of pressure is as shown in FIG.

That is, as shown in FIG. 6, the roll-shaped recording medium is being transported at a transport speed S. Timing t in this state
At step 1, the light source for exposure is turned on and exposure is started, and after exposure for a predetermined length, pressure development is started at timing t2 under pressure value P. Eventually, exposure is completed at timing t3, pressure development is completed at timing t4 after being further transported by a predetermined length, and copying is completed at timing t5 after further being transported by a predetermined length.

[Problem to be solved by the invention]

However, in the conventional copying machine, exposure is performed many times when making many copies, but after the final exposure in the series of exposures (timing t3)
The transport speed of the roll-shaped recording medium and the color developing medium remained the same as the exposure speed (transport speed S) until the pressure development was completed (timing t4) and the copying was completed (timing t5). This slows down the overall speed of the copying machine and takes a long time for the user to obtain an output image (copy image) after exposure, which is not desirable for the user. Moreover, the same thing can be said when only - copies are to be made.

As a means to solve this problem, it is possible to increase the transport speed S immediately after the final exposure and during pressure development (for example, a short time after timing t2).
In this case, the density of the output image differs before and after changing the conveyance speed S.

The reason for this is that the pressure value P of the pressure developing device remains the same as before the conveyance speed was changed, so the pressure value per unit length decreases, and as a result, the capsules described above are not destroyed sufficiently, and the output image This is because the concentration of

The present invention has been made to solve the above-mentioned problems, and provides an image forming apparatus that does not cause density differences in output images even when the conveyance speed during pressure development after exposure is increased and the copying time is shortened. The purpose is to

[Means to solve the problem]

In order to achieve this purpose, images formed by document scanning are sequentially exposed on the exposure surface of a photosensitive and pressure sensitive recording medium that is transported at a predetermined speed, and after this exposure, the light and pressure sensitive recording medium is transported at the same speed as the predetermined speed. In an image forming apparatus that forms an image by pressure development on a color developing medium, after the final exposure step of a series of exposures, the pressure of the pressure development increases as the transport speed of the light-sensitive pressure-sensitive recording medium increases during pressure development. It is characterized by being able to increase the value.

[Effect]

After the final exposure of the series of exposures to the photosensitive pressure sensitive recording medium, the transport speed of the recording medium during pressure development is increased.

Then, the pressure value for pressure development increases in accordance with the increase. As a result, the pressure per unit length of the output image is controlled to an optimum value, so that the microcapsules are sufficiently destroyed and no difference in density occurs in the output image.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. The mechanical structure of the image forming apparatus is the same as that shown in FIG. 5, except for the pressure adjusting section of the pressure developing device, which will be described below, so illustration thereof will be omitted.

FIG. 1 is a block diagram of a pressure adjusting section of a pressure developing device used in an image forming apparatus according to the present invention.

As shown in FIG. 1, a ROM 2 in which a program for controlling the device is stored and a RAM 3 in which data is temporarily stored are connected to the CPUI. The CPU also includes a transport motor driver 5 that drives the transport motor 4, a transport motor encoder 6 that detects the rotation angle of the transport motor 4, and a pressurizing motor driver 8 that drives the pressurizing motor 7. A pressurizing motor encoder 9 that detects the rotation angle of the pressurizing motor, a lamp drive circuit 11 that turns on and drives a lamp (exposure light source) 10, and a light amount sensor 12 that detects the amount of light from the lamp 10 are connected.

Next, the operation of this embodiment will be explained with reference to the time chart shown in FIG.

The rotation of the transport motor 4 transports the roll-shaped recording medium at a transport speed S1. The conveyance speed is detected by the encoder 6 and fed back to the CPUI, and is maintained at a constant conveyance speed S1 under the control of the CPUI. The lamp 1o is transported at a constant speed s1, and at timing tll, the lamp 1o driven to be lit by the lamp drive circuit 11 is lit.

When a predetermined period of time has elapsed, at timing t12, the pressurizing motor driver 8 rotates the pressurizing motor 7, and pressure development is started at a pressure value Pt. As a means for this pressure development, for example, the "eccentric cam type" shown in Fig. 3 is used.
There is also a "hydraulic type" shown in Figure 4. Their configuration and operation will be described later. At the start of pressure development, the transport speed remains at Sl. After pressure development is carried out for a while, the lamp 1o is turned off at timing t13, and the exposure is completed. Simultaneously with this timing tI3, the conveying speed is increased from S2 to 82, and the pressure value is increased from P2 to P2. The conveyance speed S2 is continued until copying is completed at timing t15. Even if the conveyance speed is increased in this way, the pressure value is also increased at the same time, so the pressure per unit length of the roll-shaped recording medium does not become weaker.

That is, the increase in the conveyance speed is detected by the conveyance motor encoder 6 and fed back to the CPUI, and the pressurization motor encoder 9 feeds back the increased speed of the pressurization motor 7 to the CPUI. Based on these two fed-back values, the speed of the pressurizing motor 7 is controlled so that the CPUI reaches the optimum pressure. As a result, the color developer applied to the roll-shaped recording medium is destroyed as desired, so that no shading occurs on the copy screen.

Next, the "eccentric cam type" pressurizing means shown in FIG. 3 will be described. The rotation of the drive shaft 7a of the pressurizing motor is as follows:
It is transmitted to the eccentric cam 22 via the chain 21. The outer peripheral surface of the eccentric cam 22 is in close contact with the outer peripheral surface of the backup roller 63b.

The backup roller 63b is rotatable around the shaft 63b1. The backup roller 63b moves up and down in accordance with the rotation of the eccentric cam 22.

As a result, the mutual pressure between the developer paper and the roll-shaped recording medium (not shown) sandwiched between the backup roller 63b and the small-diameter roller 63a biased by the compression spring 23 is changed.

Further, the case of the "hydraulic" pressurizing means shown in FIG. 4 will be described. As shown in FIG. 4, a pinion 24 is fitted into the drive shaft 7a of the pressurizing motor. pinion 24
is engaged with a rack 26 formed on the lower surface of a piston rod 25 having a piston 25a fixed to its tip.

The piston 25a is a cylinder 27 filled with oil 32.
Move left and right inside. This horizontal movement causes the first to third pistons 28a disposed in the holes provided in the cylinder 27 to
~28c uniformly move left and right. 1st to 3rd piston 28
L-shaped mounting brackets 29a to 29c are fixed to the tips of a to 28c, respectively. Mounting bracket 2
Backup bearings 30a to 30c, which are rotatable about the shaft, are attached to the tips of 9a to 29c.

The outer circumferential surfaces of the backup bearings 30a to 30c are pressed into close contact with the outer circumferential surface of the backup roller 63b.

The small diameter roller 63a is biased by springs 31a to 31c, and the small diameter roller 63a and the backup roller 63b
and are pressed closely together. With this configuration, the piston 25a moves left and right according to the rotation of the drive shaft 7a, and the backup bearings 30a to 30c move left and right in accordance with this movement. As a result, the roll-shaped recording medium sandwiched between the backup roller 63b and the small-diameter roller 63a and the developer paper are brought into pressure contact, and pressure development is performed. At this time, the optimal pressure value is ensured by appropriately controlling the rotation of the drive shaft 7a.

In this embodiment, the case where the original is moved and the light source is fixed has been described, but it goes without saying that the present invention can also be applied to the case where the original is fixed and the light source is moved.

〔Effect of the invention〕

As is clear from the detailed description above, according to the present invention,
After the final exposure of a series of exposures is completed, even if the conveyance speed of the photosensitive and pressure sensitive recording medium is increased, the pressure value for pressure development is also increased at the same time, so the resulting copy image is output as an image that maintains its original density. Ru. Therefore, the copying speed of the copying machine can be increased while maintaining high quality images.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a pressure adjustment section used in an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a time chart showing the operation of the image forming apparatus according to the present invention, and FIGS. 3 and 4 are according to the present invention. FIG. 5 is a side view showing the mechanical configuration of a conventional image forming apparatus. FIG. 6 is a time chart showing the operation of the conventional image forming apparatus. 1... CPU 4... Transport motor 7... Pressure motor 10... Lamp (exposure light source) 61... Microcapsule paper (photosensitive pressure sensitive recording medium)
・Developer paper (color developer medium)

Claims (1)

[Scope of Claims] Images formed by scanning an original are sequentially exposed on the exposure surface of a photosensitive and pressure-sensitive recording medium that is transported at a predetermined speed, and after this exposure, a microscope that is transported at the same speed as the predetermined speed is used. In an image forming apparatus that forms an image by pressure development on a color medium, after the final exposure step of a series of exposures is completed, the pressure value of the pressure development is adjusted according to the increase in the conveyance speed of the light-sensitive pressure-sensitive recording medium during pressure development. An image forming apparatus characterized in that it can be raised.