JPH0445444A - Image forming device - Google Patents

Abstract

PURPOSE:To carry out an optimum stable thermal fixing even if a factor is changed by changing at least one of three control operating quantities of the heating temp., passing speed, and pressurizing force of a development sheet on a thermal fixing device, based on the detected result of the size, material, and thickness of the development sheet. CONSTITUTION:The material of the development sheet 22 is discriminated. When the development sheet is a translucent one for OHP, continuously, it is discriminated whether its size is A3 or not. When the size is A3, control is carried out so that the pressurizing force is low by obtaining a gap between a heating roller 53 and a pressure roller 56, the passing speed of the development sheet is low by reducing the speed of a driving motor, and the temp. of the surface of the roller 53 is high. When the size is A4, the control is carried out so that the pressurizing force is low, the passing speed is more or less low, and the temp. of the surface of the roller 53 is high. When the material is for a normal sheet, the discrimination of the size is carried out. When the size is A4, further, the thickness of a sheet is discriminated. When the thickness of the sheet is <=100 microns, the control is carried out so that the pressurizing force is low, the passing speed is high, and the temp. of the heating is low. When the thickness of the sheet exceeds 100 microns, the control is carried out so that the pressurizing force is more or less low, the passing speed is more or less high, and the temp. of the heating is more or less low.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus using a photosensitive and pressure sensitive recording medium, and more specifically, to control of a heat fixing device thereof.

[Conventional technology]

In this type of image forming apparatus, a photosensitive pressure-sensitive recording medium is used as a microcapsule sheet that encapsulates a dye precursor that develops color by reacting with a color developer and supports microcapsules whose mechanical breaking strength changes in response to light. The latent image formed by exposing the light-sensitive and pressure-sensitive recording medium is transferred by placing it on a color developer sheet carrying at least a color developer on its surface and applying pressure.

Next, the prior art proposed by the present applicant, JP-A-2-
As disclosed in Japanese Patent No. 64640, a color developing sheet separated from a transferred microcapsule sheet is sent to a heat fixing device.

In the device, a conveyor belt is wound between a heating roller and a paper ejection roller, a pressure roller is provided facing the heating roller, and a pressure roller is provided between the conveyor belt and the pressure roller around the outer periphery of the heating roller. When heat and pressure are applied to the surface of the color developing sheet, approximately 1
The color developer on the surface of the color developer sheet melts at a temperature of 00℃,
The color development reaction is promoted and a color image is developed on the surface of the color developer sheet, and the surface is mirror-finished to give the surface of the color developer sheet an appropriate gloss, and then the color developer is solidified by cooling. So-called heat fixing is performed.

[Problem to be solved by the invention]

In this case, the quality of the heat fixing finish depends on the amount of heat applied to the color developer sheet, the heat fixing time (in other words, the speed at which the amount of heat is applied, and the speed at which the color developer sheet passes through the heat fixing device). It is determined by the pressing force per unit area of the color developing sheet.

For example, as disclosed in the above-mentioned prior art, it is necessary to strictly control the surface temperature of the color developer sheet to around 100°C; if this temperature is too high, the image will stick to the belt, and if it is too low, the gloss will be reduced. Does not appear.

In addition, to achieve high gloss, heat for about 0.2 to 0.3 seconds.
This requires pressurization time.

By the way, the paper that is the base material of the color developer sheet on which the color developer is supported includes ordinary paper and transparent sheets (synthetic resin sheets) for 0HP (overhead projection). The size of the paper and the thickness of the paper can also be changed in various ways by the user as needed.

Size, paper thickness, paper quality (material) of such color developer sheet
If the factors change, optimal heat fixing cannot be achieved unless the control operations of the heating temperature, paper passing speed, and pressure force adjustment sections are changed.
The control operation amount of each of the above-mentioned adjustment parts was set to optimize heat fixing for standard paper thickness and size, and the heat fixing state was fixed, so if paper-related factors such as size changed, stable results would be achieved. Heat fixation could not be expected.

The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a heat fixing device that can adjust the amount of control operation for heat fixing according to changes in paper-related factors. The purpose is

[Means to solve the problem]

In order to achieve the above object, the present invention provides an image forming apparatus using a photosensitive pressure sensitive recording medium, which includes a heat fixing device through which a color developer sheet having a latent image transferred from the photosensitive pressure sensitive recording medium passes through.
A belt wrapped between a heating roller and a discharge roller,
and a pressure roller that presses toward the heating roller, and has detection means that detects the size, material, and thickness of the color developing sheet, and based on the detection results, the heating roller and the pressure roller A control means is provided for changing at least one of the pressure applied to the roller, the heating temperature for the color developer sheet, and the passing speed of the color developer sheet.

〔Example〕

Hereinafter, embodiments embodying the present invention will be described based on the drawings.

FIG. 1 shows a photosensitive and pressure-sensitive copying machine that implements the image forming apparatus of the present invention.

In the copying machine 20 of this embodiment, as shown in FIG. 1, photosensitive paper consisting of microcapsule paper 21 and color developer sheet 22 is used as a photosensitive and pressure sensitive recording medium.

In addition, the microcapsule paper 2 used in this example
Microcapsules are coated on the surface of 1, and the microcapsules contain dye precursors and the like that react with a color developer described later. A color developer is coated on the surface of the color developer sheet 22, and develops color by reacting with a dye precursor, but the details are described in US Pat. No. 4,399,209, and will not be described here.

A desired document 25 is placed face down on a document table glass 23 disposed at the top of the copying machine 20, and the upper part thereof is covered with a document table cover 24.

A halogen lamp 26 is provided below the document table glass 23.
A shaft 28 on which a light source unit 26 including a reflector 26b, a reflection mirror 27, etc. is installed parallel to the document table glass 23.
It is arranged so that it can be moved back and forth along.

The light from the light source unit 26 is irradiated in a line shape in a direction perpendicular to the moving direction toward the document table glass 23, and the irradiated light passes through the transparent document table glass 23 and is placed on the document table glass 23. The light is reflected downward by the scratched original 25.

The light reflected from the original is reflected in the order of the reflection mirror 27 in the light source section 26 and the reflection mirrors 29a and 29b in a mirror part 29 that is movable separately from the light source section 26, is guided so that it is parallel to the direction of movement.

A normally fixed projection lens 30 and a filter 31 for adjusting the color tone of the copied image are disposed below the document table glass 23, and the light reflected by the reflection mirror 29b is directed to the projection lens 30. incident. The lens 30
The light projected by is reflected by reflection mirror groups 32a and 32b.

The reflection mirror groups 32a and 32b are arranged on the axis 2 in order to change the optical path length according to the change in the projection magnification m when enlarging or reducing the size of the latent image formed on the microcapsule paper 21.
8 in the axial direction.

An exposure table 33 for exposing the microcapsule paper 21 is arranged on the right side of the reflection mirror 32b, and a reflection mirror 32c for switching the optical path is arranged between the reflection mirror 32b and the exposure table 33. It's there. Image information on the original 25 is formed on the microcapsule paper 21 disposed along the exposure table 33 .

On the other hand, a removable cartridge 34 is disposed in the center of the copying machine 20, and the cartridge shaft 34 is disposed at the center of the copying machine 20.
A long length of microcapsule paper 21 in a state of being rolled up into 5 pieces is housed therein.

Further, this copying machine has an autoloading function for automatically setting the microcapsule paper 21 on a predetermined transport path within the machine.

Reference numeral 36 denotes a half-moon roller for drawing out the leader film portion attached to the tip of the microcapsule paper 21;
Reference numeral 37 denotes a tension roller, and a separation chute 39 is rotatably attached to guide the roller to the winding shaft 38. An upper winding guide 41a and a lower winding guide 41b are arranged around the winding shaft 38 for winding the leader film.

Microcapsule paper 2 coming out from the top of the cartridge 34
1 is guided by a tension roller 37 and passes above the exposure table 33, and then passes through a pressure developing device 42 that includes a feed roller 40a, a dancer roller 40b for tension adjustment, and a large diameter roller 42a and a backup roller 42b. The sheet passes through the sheet, is further guided to a separating roller 43, and then wound onto a winding shaft 38.

As a result, the microcapsule paper 21 following the leader film portion is also wound up on the winding shaft 38, and the setting in the apparatus is completed.

Note that the unexposed microcapsule paper 21 after leaving the cartridge 34 is maintained in an unexposed state by a light shielding cover or the like.

On the other hand, a removable device provided below the pressure developing device 42;
The developer sheets 22 housed in a replaceable paper feed cassette 45 are taken out one by one by a suction cup type paper feed mechanism 46 that sucks paper using negative pressure suction. Feed rollers 47a and 47 are provided between the paper feeding mechanism 46 and the pressure developing device 42.
b, 47c.

It is conveyed by the feed guide 47d and carried into the pressure developing device 42.

In this case, the microcapsule paper 21 and the color developer sheet 22 are brought into close contact with each other by the pressure developing device 142, the latent image is transferred from the microcapsule paper 21 to the color developer sheet r-22, and then separated by the separation roller 43. The color developer sheet 22 is sent to a heat fixing device 44, which will be described later.

A heat fixing device 44 is disposed to the right of the pressure developing device 42, and a paper discharge tray 48 for storing the color developer sheet 22 on which an image is formed is disposed to the right of the heat fixing device 44. It is set up.

The heat fixing device 44 fixes the color developing sheet 22 with the surface facing upward.
a pair of feed rollers 50 for conveying the material in the direction of arrow A;
50, a guide plate 52.52 disposed adjacent to the pair of feed rollers 50.50, and an endless belt 55 which is wound around and driven to rotate between a heating roller 53 and a discharge roller 54 disposed between a pair of frames 51.51. and a pressure roller 56 that presses against the heating roller 53. Reference numeral 57 is a support plate that receives the color developing sheet 22.

A heater 58 is disposed inside the heating roller 53, and the developing sheet 22 is heated and pressurized between it and the pressure roller 56, and is separated at the discharge roller 54 side while being cooled as the belt 55 moves. do.

Numerals 59 and 59 are bearings for rotatably supporting both ends of the support shaft 60 of the heating roller 53 on the frame 51.51, and 61 and 61 are bearings for rotatably supporting both ends of the support shaft 62 of the discharge roller 54. The two bearings 61.
61 is a longitudinal guide groove 63 bored in the frame 51°51.
63 so as to move toward and away from the support shaft 60 of the heating roller 53 .

Reference numeral 64 applies an equal tensile force to both ends of the discharge roller 54 in the direction away from the heating roller 53;
The urging means 64 is configured to eliminate meandering of the belt 55, and the urging means 64 includes a pair of outer rings 65 and 65 rotatably fitted onto both ends of the support shaft 62 of the discharge roller 54;
A pair of tension bodies 66.66, such as wires, one end of which is attached to the bipolar ring 65, one biasing spring 67, such as a coil spring, connecting the other ends of the pair of tension bodies 66.66; Roller 68 guiding the middle part of tension body 66.66
, 68, and each roller 68 has a bracket 69.
It is fixed in position by being attached to the frame 51 via a.

Reference numeral 70 denotes a pressure adjustment driving means for the pressure roller 56, and a pivot shaft 7 rotatably mounted on the frame 51.51.
A spindle 74 of the pressure roller 56 is rotatably supported by an arm 72 fixed to one end of the swing arm 72 and a swing arm 73 fixed to the other end of the swing arm 73.
The eccentric cam 76 is always in contact with the circumferential surface of the swing arm 73, and the eccentric cam 76 is rotated by a step motor 79 via a pair of gears 77 and 78 to change and adjust the swing angle of the swing arm 73. Accordingly, the pressure force can be adjusted to be stronger or weaker.

Reference numeral 80 is a drive motor that drives the heating roller 53 and hence the belt 55. Above the heat fixing device 44, a gas adsorption device (not shown) is installed in a casing 82 in order to remove the odor of the gas generated during the heat fixing process. Gas adsorption filter device 81 equipped with a filter body and an exhaust blower
The gas adsorption filter body is replaced when a certain amount of gas is adsorbed.

Reference numeral 83 is a cooling fan for sucking out air from the optical system of the copying machine (2) to cool it.

Reference numeral 85 indicates the size of the color developing sheet 22 (for example, A4
．． Different paper feed cassettes 45 are prepared for each size of the color developing sheet 22 which is paper, and a different replaceable paper feed cassette 45 is installed in the copying machine 20 for each size. The size sensor 85 may be provided at a location where the image is to be printed, or a size designation switch provided at a location on the operation panel (not shown) of the copying machine 20 may be used as the size sensor.

Next, reference numeral 86 is a material sensor for detecting the material of the color developing sheet 22 (for example, plain paper, translucent sheet for OHP), and the material sensor 86 detects the material of the color developing sheet 22 which is paper (for example, plain paper, translucent translucent sheet for OHP). A light-transmitting material sensor 86 is provided on the conveyance path between the paper feed mechanism 46 and the pressure developing device 42 to detect the color developer sheet 22, which is fed out from the paper feed cassette 45 and reaches °C. ° To detect the material
Alternatively, the material may be detected by the user pressing a material designation switch provided on the operation panel (not shown) of the copying machine 20 in the same manner as described above.

Reference numeral 87 denotes a paper thickness sensor for detecting the paper thickness of the color developer sheet 22, which is located at a pair of feed rollers provided in the conveyance path between the paper feed mechanism 46 and the heat fixing device 44. can be provided.

That is, one of the pair of feed rollers is fixed in position, and the other roller is a movable pressure roller, and the thickness of the color developing sheet 22 (paper) that passes between the pair of rollers is determined. The thickness of the paper can be detected by detecting the amount by which the movable pressure roller retreats in response to the movement of the movable pressure roller.

Reference numeral 8B is a central processing unit (CPU) of the control device using a microcomputer, and 88 is provided with an input/output interface, a read-only memory (ROM), and a read/write memory (RAM).

Then, the detection signals of the three sensors 85, 86, and 87 are input to the central processing unit 88, and based on these detection signal values, the central Heat fixing device 44 in processing device 88
Determine the optimal pressure, heating temperature, and heat fixing speed (passing speed of the color developing sheet), and
The step motor 79 in the pressure adjustment driving means 70 of the pressure roller 56 is operated in the forward or reverse direction, or the heater 58 is turned on and off, and the drive motor 8 is
The rotational speed of the heating roller 53 and the belt 55 due to the rotation speed is controlled to be increased or decreased.

In this case, for example, the optimum value of the heating amount to the color developer sheet 22 per unit area per unit time is approximately constant, so when the color developer sheet 22 is large in size or the paper is thick, The heating temperature should be increased or the heat fixing speed (passage speed of the color developer sheet) should be slowed down, and the optimal value per unit area of the color developer sheet is approximately constant regarding the pressing force (surface pressure). If the developing sheet is large, the total pressing force should be increased, and if the paper is thick, the gap between the heating roller and pressure roller should be increased (to adjust the surface pressure). Should.

Furthermore, the material of the color developer sheet is more O-resistant than plain paper.
The amount of heating should be large for the light-transmitting sheet for HP, but the pressing force (surface pressure) for the light-transmitting sheet for OHP should be lower.

For this reason, the step motor 79 and the heater 5
8 and the drive motor 80 may be operated simultaneously, or two or one of them may be operated.

Next, the operation of this copying machine will be explained.

When the cartridge 34 is set in the copying machine 1 and the leader film attached to the tip of the microcapsule paper 21 is wound around the winding shaft 38, the auto-loading is completed, the upper winding guide 25 and the lower winding guide 26
, the separation chute 27 returns to the position shown by the solid line, and copying becomes possible.

When the copy start key is operated, the reflection mirror 2
7. The halogen lamp 26a has a moving speed of 1 / assuming that the transport speed of the microcapsule paper 21 is V and the projection magnification is m.
mV, and the reflecting mirrors 29a and 29b move at a moving speed of 1/2 mV.

The conveyance speed of the microcapsule paper 21 is as follows: Mira group 27.
Since the moving speeds of the document sheets 29 a and 29 b are synchronized as described above, latent images of predetermined lines of the original document 25 are sequentially formed on the microcapsule paper 21 as it passes through the exposure table 33 . Note that the predetermined speed ratio is predetermined based on the setting of the magnification.

The pressure developing device 42 is supplied with the microcapsule paper 21 on which the latent image is formed and the color developer sheet 22 in a state in which they are in close contact with each other and integrated, and the microcapsule surface of the microcapsule paper 21 on which the latent image is formed is supplied. and the color developer coated surface of the color developer sheet 22 are in contact with each other on the inside, and are sandwiched between the large diameter roller 42a and the backup roller 42b, and pressure is applied. This pressure destroys the unexposed microcapsules and transfers the image onto the color developer sheet 22.

After the microcapsule paper 21 and the color developing sheet 22 that have come out of the pressure developing device 42 are separated by a separation roller 43,
After the color development of the color developing sheet 22 is promoted by the heating roller 53 of the heat fixing device 44 and six images are formed, the color developing sheet 22 is conveyed to the paper discharge tray 48 from the discharge roller 54 side.

FIG. 6 is a flowchart (subroutine) showing an example of control of the heat fixing device 44 by the central processing unit 88, and executes the following control.

That is, following the start, in step 601, the material of the color developer sheet 22 is determined, and if the color developer sheet is not plain paper (no
), that is, in the case of an OHP translucent sheet, it is then determined in step 602 whether or not the size is A3.

When the size is A3, in step 603, a gap is opened between the heating roller 53 and the pressure roller 56 to reduce the pressing force, the drive motor 80 is decelerated to reduce the passing speed of the developing sheet, and the heating is performed. Control is performed to increase the surface temperature of the roller 53.

When the size is A4, in step 604, the pressing force is low, the passing speed is slightly slow, and the heating roller 5 is
Execute control to raise the surface temperature of step 3.

In addition, when the color developing sheet is a translucent sheet for OHP,
Since the thickness of normally used sheets is constant, the paper thickness is not determined.

When it is determined in step 601 that the material is plain paper (if YES), the size is determined in step 605.

If the size is A4 (no), the paper thickness is further determined in step 606.

In this step 606, the paper thickness is set to 100 microns (
There are two types of discrimination: those thicker than 100 microns and those thicker. If the thickness is less than 100 microns (yes), in step 607, the pressurizing force is lowered, the passing speed is high, and the heating temperature is lowered. Control as follows.

In step 606, the paper thickness exceeds 100 microns (
When it is determined that no), in step 608,
The pressing force is slightly lower, the passing speed is slightly higher, and
Control the heating temperature to be slightly low.

When the size is A3 in step 605, the paper thickness is determined into two types in step 609 as in step 606, and if the paper thickness is 100 microns or less (yes
), in step 610, the pressing force is controlled to be a little thick (and the passing speed is a little slow), and the heating temperature is controlled to be a little high.

In step 609, the paper thickness exceeds 100 microns (
If the determination is no, in step 611, the pressurizing force is increased, the passing speed is decreased, and the heating temperature is controlled to be high.

Note that the heat fixing device 44 may be of a type that heats the color developing sheet 22 with hot air, or heats it in an oven style with a heater or infrared irradiation at a location other than the pressure roller pair. .

Furthermore, it goes without saying that the present invention can also be applied to a copying machine equipped with both a monochrome laser printer and a color image forming apparatus.

[Operation and effects of the invention]

In this way, based on the results of detecting the size, material, and paper quality of the color developer sheet, at least one of the three control operation quantities, namely the heating temperature, passing speed, and pressing force of the color developer sheet in the heat fixing device, is controlled. Since it can be adjusted by changing the color developer sheet, it is possible to perform the heat fixing work in detail according to the three factors of size, material and paper quality of the color developer sheet, and the above-mentioned factors regarding the color developer sheet can be changed. This also has the remarkable effect of providing optimal heat fixing and making stable heat fixing possible.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram of a copying machine, FIG. 2 is a perspective view of main parts of a heat fixing device, FIG. 3 is a plan view, and FIG. 4 is an IV diagram of FIG. 3. -IV sectional view, FIG. 5 is a block diagram of the control device, and FIG. 6 is a flowchart. 20... Copying machine, 21... Microcapsule paper, 2
2... Color developer sheet, 26... Light source section, 42... Pressure developing device, 44... Heat fixing device, 45... Paper feed cassette, 48... Paper output tray, 51.51 ...Frame, 53...Heating roller, 55...Belt, 56
...Pressure roller, 58...Heater, 60.62...
・Support shaft, 63... Guide groove, 65... Outer ring, 6
4... Urging means, 70... Pressure adjustment drive means, 73
... Swinging arm, 75 ... Trochanter, 76 ... Eccentric cam, 79 ... Step motor, 80 ... Drive motor, 85 ... Size sensor 86 ... Material sensor 87 ... -Paper thickness sensor 88...Central processing unit.

Claims (1)

[Claims] (1) In an image forming apparatus using a photosensitive pressure sensitive recording medium, a heat fixing device through which a color developing sheet having a latent image transferred from the photosensitive pressure sensitive recording medium passes is wound between a heating roller and a discharge roller. It is composed of a belt that is hung over the belt and a pressure roller that presses against the heating roller, and has a detection means that detects the size, material, and thickness of the color developing sheet, and based on the detection results, the An image forming apparatus comprising a control means for changing at least one of the pressing force between a heating roller and a pressure roller, the heating temperature for a color developer sheet, and the passing speed of the color developer sheet.