JPH057702B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention uses a light-receiving sheet and an image-receiving sheet,
The present invention relates to an image forming apparatus that heats an image-receiving sheet on which an image has been formed after development and transfer to give gloss to the image.

(b) Prior art A light-receiving sheet coated with microcapsules containing a photocurable material and a colorless dye;
In an image forming apparatus using a developing material that develops the colorless dye and an image receiving sheet coated with a thermoplastic resin, the microcapsules are partially cured by image-forming exposure, and a selectively cured image is formed. The image receiving sheet is superimposed on the receiving sheet and pressurized to form a colored image on the image receiving sheet. Generally, in order to make a good image formed on this image-receiving sheet, heating the image-receiving sheet melts and softens the thermoplastic resin coated on the surface of the image-receiving sheet, and coats the image with gloss. is giving.

The heating methods used at this time include an oven method in which the image receiving sheet on the conveyance section is indirectly heated from above by a heater, and a heating roller equipped with an internal heating source such as a halogen lamp and a pressure roller that presses against the heating roller. There is a heat roller method, and a heat roller + glossy sheet method in which heat is heated by a belt-shaped heat-resistant glossy sheet stretched between a heating roller that is similarly equipped with a heat source such as a halogen lamp inside the roller.

(c) Problems to be Solved by the Invention However, the material of the image receiving sheet includes paper, overhead projector (OHP) sheet, etc., and each sheet has a different thickness. The amount of heat required for glossiness varies depending on the material and thickness of the image-receiving sheet, so no matter which heating method is used above, heating at the same temperature will result in a difference in glossiness in the case of paper, depending on the material and thickness of the image-receiving sheet. There was a problem in that variations occurred, and in the case of OHP sheets, variations in light transmittance occurred.

This invention was made in view of the above-mentioned problems, and by variably setting the heating temperature in the image glossing device according to the material and thickness of the image-receiving sheet, stable gloss can be achieved for any image-receiving sheet. Another object of the present invention is to provide an image forming apparatus that can obtain stable light transmittance.

(d) Means for Solving the Problems The image forming apparatus of the present invention comprises a light-receiving sheet coated with microcapsules containing a photocurable material and a colorless dye, a developing material for coloring the colorless dye, and a thermoplastic resin. an image-receiving sheet coated with the image-receiving sheet, and a pressure means for developing and transferring the image-receiving sheet by applying pressure while superimposing the image-receiving sheet on the light-receiving sheet on which a selectively cured image has been formed by image-forming exposure; The image receiving sheet is characterized by being provided with a heating means for heating the image receiving sheet after being pressed, and a means for variably setting the heating temperature of the heating means according to the material and thickness of the image receiving sheet.

(e) Effect In the image forming apparatus according to the present invention, the relationship between the material and thickness of the image receiving sheet and the heating temperature is stored in advance according to the heating method of the heating means. When the material and thickness of the image-receiving sheet are input from the operation panel, or when a detection signal from the image-receiving sheet detection means is input, the optimum heating temperature for the material and thickness is determined based on the material and thickness of the image-receiving sheet. The heating temperature is determined based on the temperature relationship and is set according to the material and thickness of the image receiving sheet. The image-receiving sheet, which has been developed and transferred to form an image, is heated at a temperature optimal for its material and thickness to obtain an image with stable gloss or light transmittance.

(f) Embodiment FIG. 6 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention.

A main drum 41 is disposed approximately at the center of the image forming apparatus main body 40 . On the left side thereof, a light-receiving sheet roller 42 that is an unused light-receiving sheet rolled into a roll, and a take-up roller 43 that winds up a used light-receiving sheet are disposed. Light-receiving sheet roller 42 The light-receiving sheet is wound onto the winding roller 43 via the main drum 41 . Note that at this time, the microcapsule coating surface of the light-receiving sheet was on the outside.

A document table 50 is arranged on the upper surface of the main body 40, and an optical system 51 including a light source, mirror, lens, etc. is arranged below it.

A paper feed cassette 44 is provided on the right side of the main body 40, and a paper feed roller 44a and a PS roller 44b are provided on the paper feed side of the paper feed cassette 44. A pressure roller 45 is located below the main drum 41.
A peeling claw 46 is provided near the contact point.

The image forming process in the image forming apparatus will be explained.

The original on the original platen 50 is scanned by the light source of the optical system 51, and its reflected light is guided to the exposure point P1 of the main drum 41. As a result, the microcapsules of the light-receiving sheet placed on the main drum 41 are partially cured, and a selectively cured image is formed. The image-receiving sheet in the paper feed cassette 44 is fed by a paper feed roller 44a, comes into contact with a PS roller 44b, and is temporarily stopped. On the other hand, the pressing roller 45 is pressed against the main drum 41 by a pressing mechanism (not shown). This pressurizing point P2 is a point where the microcapsule surface of the light-receiving sheet and the developing material surface of the image-receiving sheet are overlapped and pressed, and the PS roller 44
The image-receiving sheet once stopped at point b is fed to the pressure point P2 at the timing when the leading edge of the image-receiving sheet coincides with the leading edge of the selectively cured image on the light-receiving sheet.
As a result, the light-receiving sheet and the image-receiving sheet are overlapped and pressurized, and the uncured microcapsules of the light-receiving sheet are ruptured, and the colorless dye contained therein flows out and causes a coloring reaction with the developing material of the image-receiving sheet. .

Thereafter, the image-receiving sheet is peeled off from the light-receiving sheet by a peeling claw 46, conveyed to an image glossing device 47 by a suction belt, and after being glossed, is transferred to a sheet output tray 49 by a sheet discharge roller 48. The paper is ejected to

In the image forming apparatus of this embodiment, the material and thickness of the image receiving sheet are input from the operation panel. A heat roller + glossy sheet method is applied as a heating means, and the belt speed of the glossy sheet is increased to 20%.
Heating was performed under conditions of mm/sec and roller load of 4 kg/cm ² . In this case, the relationship between the material and thickness of the image receiving sheet and the optimum heating temperature is as shown in FIG.

FIG. 1 is a block diagram of a part of the control section of the image forming apparatus.

The control unit CPU1 of the entire image forming apparatus has ROM2.
and ROM3 are connected. In addition, the operation panel 5, other process equipment, temperature controller 6
etc. are connected to the CPU 1 via I/04, and a heater lamp 7 and a temperature sensor 8 are connected to the temperature controller 6.

The entire device is controlled by the CPU 1, and its processing program is stored in the ROM 2 in advance. The RAM 3 is a working area used when executing the processing program, and the area M stores in advance the relationship between the material and thickness of the image receiving sheet and the heating temperature for the applied heating method. An operation panel 5 is provided on the top of the main body of the image forming apparatus.
is provided, and the material and thickness of the image-receiving sheet are input using specific keys (for example, a numeric keypad). The input data from the operation panel 5 is input to I/
It is input to CPU1 via 04. CPU1 is RAM
The set temperature is determined from the relationship between the material and thickness of the image-receiving sheet and the heating temperature, which are stored in advance in area M of No. 3. The set temperature is output to the temperature controller 6 via I/04. The current supplied to the heater lamp 7 is adjusted according to the set temperature and the output of the temperature sensor 8, and the heating temperature is set to the set temperature.

FIG. 5 is a configuration diagram of a heating device applied to the image forming apparatus.

A belt-shaped glossy sheet 33 is stretched between the heat roller 30 and the roller 31, and the heat roller 30
and the glossy sheet 33 by the rotation of the roller 31.
rotates clockwise in the figure. A tension roller 32 is in pressure contact with the heat roller 30.

A heater lamp 7 serving as a heat source is disposed inside the heat roller 30, and a temperature sensor 8 is disposed on the surface of the heat roller 30. A temperature sensor 8 detects the surface temperature of the heat roller 30, and a temperature controller (not shown) detects the surface temperature of the heat roller 30.
0 surface temperature is controlled. Glossy sheet 33
When passing through the heat roller 30, the temperature rises to almost the same temperature as the heat roller 30, but as the heat roller separates from the heat roller 30 as it rotates, it gradually cools down.
The temperature of the glossy sheet 33 when it passes through the roller 31 is
It is preferable that the temperature is 20° C. or more lower than the temperature when the heat roller 30 passes, and if it is lower than that, offset is likely to occur.

Next, the operation will be explained.

An image receiving sheet S whose surface is coated with a thermoplastic resin is fed between a heat roller 30 and a tension roller 32. At this time, the paper is fed so that the thermoplastic resin coated surface faces the glossy sheet 33 side. The image receiving sheet S is pressed by a tension roller 32 while being heated by a heat roller 30 and a glossy sheet 33. This softens or melts the thermoplastic resin, and since the glossy sheet 33 has smoothness, the thermoplastic resin is sufficiently smoothed. Thereafter, the image receiving sheet S is conveyed along the glossy sheet 33, but as it is gradually cooled, it is peeled off from the glossy sheet 33 and conveyed to the left in the figure. At this time, as mentioned above, the temperature of the glossy sheet 33 is 20°C higher when it passes through the roller 31 than when it passes through the heat roller 30.
If the temperature is lower than this, the image receiving sheet S can be easily peeled off from the glossy belt 33 without causing offset.

Note that S' is the image-receiving sheet before being made glossy, and S'' is the image-receiving sheet after being made glossy.

In the above embodiment, the material and thickness of the image-receiving sheet were input from the operation panel, but it is also possible to detect the material and thickness of the image-receiving sheet after feeding with a detector, and to set the heating temperature variably according to the detection signal. .

The second embodiment is an image forming apparatus that uses a light transmittance detector to detect the material and thickness of an image receiving sheet to set the heating temperature. A block diagram of a part of the control section is shown in FIG. Since this embodiment is almost the same as the first embodiment (FIG. 1), only the different parts will be explained. A light transmittance detector 61 is provided in place of the operation panel 5 for inputting the material and thickness of the image receiving sheet, and is connected to I/04 via a detection circuit 60. The light transmittance detector 61 is connected to the paper feed cassette 44, the paper feed roller 44a and the PS roller 44b.
A light emitting element 63, a light receiving element 64,
It is composed of a sheet presence/absence detection switch 62. When the sheet presence/absence detection switch 62 detects the feeding of the image receiving sheet, the light transmittance is detected by the light emitting element 63 and the light receiving element 64. The detection signal is amplified and A/D converted by the detection circuit 60 together with the detection signal of the sheet presence/absence detection switch 62, and is input to the CPU 1 via the I/04. Based on the input signal, the CPU 1 determines the material and thickness of the image receiving sheet from the relationship between the light transmittance and the material and thickness of the image receiving sheet stored in the area M2 of the RAM ₃ , and selects the image receiving sheet stored in the area _M1. The heating temperature is set based on the relationship between the material, thickness, and heating temperature. If the transmittance is high, it is an OHP sheet, and if the transmittance is low, it is paper, and the subtle differences in each reflect the thickness.

In the third embodiment, a capacitance detector is used to detect the material and thickness of the image receiving sheet. A block diagram of a part of the control section in that case is shown in FIG. The capacitance detector 71 is composed of a pair of conductive parts 72 installed on the PS roller 44b. A signal detected by the capacitance detector 71 when the image receiving sheet is fed and passes the PS roller 44b is amplified by the detection circuit 70, A/D converted, and input to the CPU 1 via the I/04. Thereafter, the same process as in the second embodiment is performed and the heating temperature is set.

Other methods include detecting the material of the image-receiving sheet by detecting light reflectance, and detecting the thickness of the image-receiving sheet by detecting resistance.

As mentioned above, there are several types of heating methods, and any of them can be applied.

(g) Effects of the Invention In the image forming apparatus of the present invention, the heating temperature for imparting gloss to the image after development and transfer is variably set to an optimal temperature depending on the material and thickness of the image receiving sheet. Therefore, there is no variation in gloss (in the case of paper) or variation in light transmittance (in the case of OHP sheets) that occurs due to differences in the material and thickness of the image-receiving sheet, which is the case with conventional sheets, and there is always stable gloss or light transmission. Images with good accuracy can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a portion of a control section of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram of a part of the control section of the image forming apparatus according to the second embodiment. FIG. 3 is a block diagram of a part of the control section of the image forming apparatus according to the third embodiment. FIG. 4 shows the relationship between the optimum heating temperature for image glossing and the material and thickness of the image-receiving sheet when the heating means is a heat roller+glossy sheet system. FIG. 5 is a configuration diagram of a heating device of heat roller + glossy sheet type. FIG. 6 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. 42... Light-receiving sheet roller, 47... Image glossing device.

Claims (1)

[Claims] 1. Selection by image forming exposure using a light-receiving sheet coated with a photo-curing material and microcapsules containing a colorless dye, and an image-receiving sheet coated with a thermoplastic resin and a developing material that develops color from the colorless dye. a pressure means for developing and transferring the image-receiving sheet by applying pressure to the light-receiving sheet on which a cured image has been formed; a heating means for heating the image-receiving sheet after being pressed; An image forming apparatus comprising: means for variably setting the heating temperature of the heating means according to material and thickness.