JPH0769571B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an image forming apparatus using a light and pressure sensitive recording material.

(B) Conventional Technology In recent years, an image forming apparatus using a media sheet coated with photosensitive microcapsules and an image receiving sheet coated with a developer has been developed. The photosensitive microcapsule contains a light-sensitive material and a colorless dye, and a light-curable material that initiates polymerization upon light irradiation to be cured is used as the light-sensitive material (JP-A-58-88739, etc.).
When the light-curable material cures the photosensitive microcapsules exposed to the light, a selectively cured image is formed on the entire media sheet. On the other hand, the image-receiving sheet is coated with a developing material that develops the colorless dye, and when the image-receiving sheet is overlaid and pressed onto the media sheet on which the selectively cured image is formed, the photosensitive micro-sheet that has not been cured is formed. The capsule is broken, the colorless dye inside flows out, and the developer of the image-receiving sheet causes a color reaction to form an image.

US Pat. No. 4,399,209 discloses a transfer image forming system in which a media sheet is imagewise exposed and then superposed on the image receiving sheet and passed between a pair of pressure rollers. As another developing method, a three-roll type device is proposed in Japanese Patent Laid-Open No. 62-6257. US Pat. No. 4,482,624 discloses a method of performing non-imagewise exposure before or after image formation exposure or at the same time. Furthermore, an image forming method using a sheet in which three types of microcapsules having different photosensitivity are dispersed on a support is ELECTRONIC IMAGING (MORGAN-GRANPIA PUBLI
SHING COMPANY 1984.10) PHOTOCAPSULE PROCESS FOR HA
Known to RD COPY OUTPUT.

By the way, when the image receiving sheet is superposed on the media sheet on which the cured image is formed and pressed, the microcapsules in the non-exposed area on the outer side of the image receiving sheet are cleaved, and the pressing device is soiled by a colorless dye. . Further, the colorless dye adhered to the pressure device adheres to the back surface of the image receiving sheet during the next image formation, and stains the image receiving sheet. In order to eliminate such inconvenience, the applicant of the present application discloses that the non-image forming area of the media sheet is subjected to auxiliary exposure to cure the recording material, which is disclosed in Japanese Patent Application No. 62-198745.
-40935).

(C) Problem to be Solved by the Invention However, if non-imagewise exposure and exposure for curing recording material are performed with one auxiliary exposure light source, when a fuse lamp array is used, the former is about 20 W and the latter is It requires about 120W of power. The moving speed of the media sheet during image formation exposure is about 5 to 15 mm / sec, but the moving speed during the pressure development process is 45 to 90 mm / sec, and the light amount ratio to be given to both is about 100 times. Is. The reason for increasing the speed of the pressure development step is to obtain a good image of the background and to improve the overall processing speed.

If such an auxiliary exposure light source is to be driven by a DC stabilized power supply circuit, a power supply circuit having a large capacity to cope with the exposure for curing the recording material is required, and the cost and size are inevitable.

An object of the present invention is to provide an image forming apparatus in which a power supply circuit for an auxiliary exposure light source for performing non-imagewise exposure and exposure for curing a recording material can be realized by a small power supply circuit.

(D) Means for Solving the Problems The present invention provides a non-imagewise exposure of a constant light amount to an image forming area of a media sheet coated with a light and pressure sensitive recording material, and In an image forming apparatus having an auxiliary exposure light source that provides exposure for curing the recording material, a stabilizing power supply circuit that drives the auxiliary exposure light source at a constant power to perform non-imagewise exposure, and drives the auxiliary exposure light source by alternating current. A non-stabilized AC power supply circuit for performing the exposure for curing the recording material is provided.

(E) Action FIG. 7 shows an example of the characteristic curve of the media sheet coated with the light and pressure sensitive recording material. The solid line shows the case where the non-imagewise exposure is not applied, and the broken line shows the case where the non-imagewise exposure is applied. Tone reproducibility is improved by applying non-imagewise exposure in this way, but experiments have shown that the non-imagewise exposure required to obtain such effects is about 1/10 of the image-forming exposure. It's known. When the non-imagewise exposure amount is larger than this amount, the maximum density is lowered and the image becomes low in density, and when the non-imagewise exposure amount is smaller than this amount, the effect of improving the gradation reproducibility is lost. Therefore, precise light quantity control is required to perform non-imagewise exposure. On the other hand, as the exposure for curing the recording material, it is necessary to give an exposure amount enough to obtain the minimum density, but it is sufficient to completely cure the recording material, and if the exposure amount of a certain amount or more is given, the purpose is Achieved, no need for precise light control.

Therefore, in the present invention, when performing non-imagewise exposure, the auxiliary exposure light source is driven at a constant power by the stabilized power supply circuit, and particularly when performing exposure for curing the recording material, the AC power supply is not stabilized. It is driven by a circuit.

FIG. 1 shows the structure of the main part of the present invention. In FIG. 1, 1 and 2 are transformers that step down the commercial power supply voltage, and the rectifying / smoothing circuit 3 rectifies and smoothes the secondary side voltage of the transformer 2 to generate a DC voltage. The constant voltage circuit 4 stabilizes the output voltage of the rectifying / smoothing circuit 3 to generate a constant voltage. Reference numeral 6 is a lamp which is an auxiliary exposure light source, and 5 is a switch for switching the drive power source for the lamp 6. When non-image exposure is performed, the switch 5 is switched to the b side, a constant voltage is supplied to the lamp 6, and constant power driving is performed. Further, when the exposure for curing the recording material is performed, the switch 5 is switched to the side a, and the secondary side AC voltage of the transformer 1 is applied to the lamp 6 to be AC-driven.

In the configuration shown in FIG. 1, the rectifying / smoothing circuit 3 and the constant voltage circuit 4 only drive the lamp 6 so that the auxiliary exposure of about 1/10 of the image forming exposure amount is performed, and therefore the capacity is 20 W.
It can be configured with a relatively small scale circuit. One of the AC power supply circuits can be composed of only a transformer (if it is driven directly by a commercial power supply, the transformer 1 is also unnecessary), so that no special circuit is required. As a result, overall size reduction and cost reduction can be achieved.

(F) Embodiment FIG. 2 shows a schematic structure of a copying machine to which the present invention is applied. In this copying machine, a roll-shaped media sheet coated with a light- and pressure-sensitive recording material consisting of Y, M, and C microcapsules containing a colorless dye and a photo-curing agent is used. A coated cut sheet-shaped image receiving sheet is used by being loaded in a sheet feeding cassette.

In FIG. 2, the media cartridge 1 is mounted on the right end of the copying machine main body so that the media sheets 11 can be continuously supplied. The original placed on the original table 2 formed on the upper surface of the main body of the copying machine is illuminated by the illumination lamp 3
The image is illuminated by the light source, and the image is formed at point P1 on the media sheet 11 via the mirror and the lens 4. The auxiliary exposure light source 6 is arranged in the vicinity of the image forming point P1, and the media sheet
Non-imagewise exposure and exposure for curing recording material are performed on 11. This auxiliary exposure light source 6 is a fuse lamp array with B, G,
It is composed of three types of lamps 61, 62, 63 with a filter for transmitting each light of R interposed. A paper feed cassette 5 is mounted on the left side of the main body of the copying machine, and an image receiving sheet 14 is fed by a paper feed roller 12 and a timing roller 13 by an appropriate sequence.
Paper is fed in the direction. The timing roller 13 is the image receiving sheet 14
Is conveyed to the space P2 between the pressure rollers 10 at a predetermined timing. As a result, the image receiving sheet 14 is overlapped with the exposed portion of the media sheet 11 and pressed, and the selectively cured image is developed and transferred. The used media sheet 11 ′ that has passed through the pressure roller 10 is wound around the roller 15. The image receiving sheet that has passed through the pressure roller 10 is sent to the heating roller 7, where it is heated and discharged to the paper discharge tray 8. When the heating roller 7 has a surface coated with a thermoplastic resin, the heating roller 7 melts the thermoplastic resin to make the transferred image glossy.

FIG. 5 is a block diagram of the main part of the control section of the copying machine. The CPU 23 is a CPU that gives instructions to the operator, reads the operation content of the operator, and outputs a control code to the CPU 26. The CPU 26 is a CPU that controls various peripheral devices and executes a copying process. A ROM 24 in which the program is written in advance, a RAM 25 used as various working areas, and an I / O interface circuit 22 are connected to the CPU 23. The I / O interface circuit 22 is connected with a key switch 20 including a print switch operated by an operator and a document size sensor 21 for detecting a document size. The switch 26 has a ROM 27 in which the program is written in advance, a RAM 28 and I / O used as various working areas when the program is executed.
The interface circuit 29 is connected. The I / O interface circuit 29 controls the auxiliary exposure lamp.
A circuit 31 for controlling the conveyance of the media sheet and the image receiving sheet and a circuit 32 for controlling the optical system such as the control of the document illumination lamp and the scan control of the mirror are connected.

FIG. 3 shows the circuit of the blue lamp 61 and the positional relationship between the lamp 61 and the media sheet 11. In this embodiment, the document size that can be formed on the media sheet 11 is B5.
Size and A4 size.

The lamp 61 is composed of ten lamps 61-1 to 61-10 arranged along the width direction of the media sheet 11. On the other hand, images of B5 size and A4 size can be formed on the media sheet 11 such that the width direction of the media sheet 11 becomes the short side.

The lamps 61-1 to 61-10 are divided into three blocks according to the size of a document that can be formed. First, block A
Are lamps 61-1 and 61-10 at both ends, located outside the A4 size. Blocks B are 61-2 and 61-9, and are located inside the A4 size and outside the B5 size. Further, the block C is 61-3 to 61-8 inside the B5 size. These are circuit-connected for each block, and the drive power source is switched by the relay contacts RLa, RLb, RLc. VAB and VDB are provided as driving power supplies, the power supply VAB generates a power supply for completely curing the Y capsule, and the power supply VDB generates a voltage for color correction of the Y capsule, as described later. In the figure, T is a transformer that inputs a commercial power source and generates an alternating voltage of a predetermined voltage. A commercial power supply is connected to the primary winding N1 of the transformer via a relay contact RL1. AC power supply VA from the secondary winding N2
B is output, and AC power supplies VAG and VAR are output from the two taps. Here, VAB, VAG and VAR are used at the time of exposure for curing the recording material, VAB is a blue lamp power source, VAG is a green lamp power source, and VAR is a red lamp power source. A diode bridge DB is connected to the tertiary winding N3 of the transformer, and the capacitor C smoothes the rectified output. SRB, SRG, and SRR are constant voltage circuits that consist of series regulator circuits.
Outputs B, VDG and VDR.

Where VDB is the blue lamp power supply, VDG is the green lamp power supply, VD
R is the power supply for the red lamp.

Although only the blue lamp 61 is shown in FIG. 3, the green and red lamps 62 and 63 have the same structure.
The lamp 62 is the same as the 10 light source lamps 62-1 to 62-10.
It is divided into two blocks, and switching to the power supply VAG, VDG is performed by each relay contact. Also, the lamp 63 is 1
Zero light source lamps 63-1 to 63-10 are divided into three blocks, and switching to the power sources VAR and VDR is performed by respective relay contacts.

FIG. 6 shows the processing procedure of the CPU 26 shown in FIG. FIG. 4 shows an example of state changes of the original illumination lamp and the relay contacts RL1 and RLc after the print switch is operated.

As shown in FIG. 6, the CPU 26 first detects whether or not a copy start control command is issued from the CPU 23, and if there is a copy start command, turns on the relay contact RL1 (see FIG. 3) (n1 → n2). Then relay contacts RLa, RLb, RLc according to the original size data already received from CPU23.
Control the state of. If the document size is A4, RLa is VA
Side, that is, the AC power supply side, and RLb and RLc are switched to the VD side, that is, the DC power supply side (n3 → n4 → n5). Original size is B5
If so, RLa and RLb are on the AC power supply side, and RLc is on the DC power supply side (n6 → n7). As a result, non-imagewise exposure is started for the image forming area of the media sheet and exposure for curing the recording material is started for the non-image forming area. After that, low-speed conveyance of the media sheet is started, and at the timing when the media sheet is conveyed by ΔL, the original illumination lamp 3
Lights up (n8 to n10). Here, ΔL is the distance between the exposure point of the auxiliary exposure light source 6 and the image formation exposure point P1.

After that, scanning is started, and Δt starts from the timing at which the original scanning ends.
Switch the relay contacts RLa, RLb, RLc to the AC power supply side at the timing before this (n11 to n13). Here, Δt is the time required for the media sheet to be conveyed by ΔL.
(See FIG. 4) After that, at the timing when the document scanning ends, the document illumination lamp is turned off and the media sheet 11 and image receiving sheet
High-speed transport of 14 for distance L1 (n14 to n16). At this time, since all the auxiliary exposure light sources are driven by the AC power supply, the recording material curing exposure is performed on the media sheet 11. Here, the distance L1 is the distance until the trailing edge of the image receiving sheet 14 passes point P2 of the pressure roller 10 after scanning the original.

After that, it is determined whether or not a predetermined number of copies have been completed, and if not completed, the process returns to n3. If completed, the relay contact RL1 is turned off to end the auxiliary exposure, and the image receiving sheet 14 is conveyed for a certain time (n17 → n18). Therefore, although the medium sheet 11 has already stopped being conveyed at that time, the image receiving sheet 14 is conveyed to the sheet discharge tray 8 through the heating roller 7.

A copying test was conducted in the copying machine shown above. An 800 W halogen tungsten lamp is used as the original illumination lamp, the image formation exposure speed is 8.0 mm / sec, the media sheet conveyance speed during development is 65 mm / sec, and the voltage applied to the auxiliary exposure lamp during non-imagewise exposure is DC. When the voltage applied to the auxiliary exposure lamp at the time of exposure for curing the recording material was set to 24V and 85V, an extremely high quality image satisfying all of the gradation reproducibility, the contamination of the pressure roller and the backside stain of the image receiving sheet was obtained. I was able to get it.

(G) Effects of the Invention As described above, according to the present invention, when the non-imagewise exposure is applied to the media sheet, the auxiliary exposure light source is driven by the stabilizing power supply circuit, so that the stable non-imagewise exposure is performed. When the exposure for curing the recording material is performed, the auxiliary exposure light source is driven by the destabilizing AC power supply circuit to completely cure the photosensitive pressure-sensitive recording material. Therefore, the pressure roller and the like are not contaminated, and the back of the image receiving sheet is not stained. Moreover, since the non-stabilized AC power supply circuit is used as the light source for the exposure for curing the recording material which requires relatively high power, the cost and the size can be reduced as the power supply circuit for the auxiliary exposure light source.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a main part of the present invention. Second
FIG. 3 is a schematic configuration diagram of a copying machine according to an embodiment of the present invention,
FIG. 1 is a diagram showing a configuration of an auxiliary exposure light source and its driving power source in the copying machine. FIG. 4 is a diagram showing changes in the states of the original illumination lamp and the auxiliary exposure lamp control relay contact after the print switch is operated. FIG. 5 is a block diagram of a control unit of the copying machine, and FIG. 6 is a flowchart showing a processing procedure of the CPU 26 in the control unit. FIG. 7 is a diagram showing an example of a characteristic curve of a media sheet. 1 ... Step-down transformer (unregulated AC power supply circuit), 2 ...
Step-down transformer, (2,3,4) …… Stabilized power supply circuit, 6 ……
Auxiliary exposure light source, 61, 62, 63 ... Auxiliary exposure lamp.

Continuation of front page (56) Reference JP-A-63-157152 (JP, A) JP-A-59-30537 (JP, A) JP-A-54-36946 (JP, A) JP-A-49-105539 (JP , A) JP-A-59-149343 (JP, A) JP-A-58-88739 (JP, A) Actual development 61-126245 (JP, U) U.S. Pat. No. 4,842,976 (US, A) U.S. Pat. No. 4,482,624 (US, A)

Claims (1)

[Claims] 1. A non-imagewise exposure of a constant light amount is applied to an image forming area of a media sheet coated with a light and pressure sensitive recording material, and the non-image forming area of the media sheet is exposed to cure the recording material. In an image forming apparatus having an auxiliary exposure light source for providing, a stabilizing power supply circuit for driving the auxiliary exposure light source at a constant power to perform non-imagewise exposure, and an AC drive for the auxiliary exposure light source to perform the exposure for curing the recording material. An image forming apparatus comprising an unstabilized AC power supply circuit.