JPH0432843A - Heat fixing device - Google Patents

Abstract

PURPOSE:To remove the waste of heat efficiency and to rapidly execute a required operation such as warming-up by controlling a cooling device with a controlling means for controlling the operation of a belt cooling device based upon the sound of belt or the current state of a heat fixing device. CONSTITUTION:This heat fixing device is provided with a heat roller 40, a tension roller 43, a belt 44 and a nip roller 45 for pressing against the heat roller 40 through the belt 44 and constituted so as to heat a sheet while carrying it by the rotation of the belt 44 and also a cooling means 46 arranged oppositely to a part of the belt 44 stretched through the rollers 40, 43 and a control means for controlling the drying/stopping of the means 46. The cooling device 46 is controlled based upon the temperature of the belt 44 or at the time of warming-up. Consequently, the heat efficiency can be prevented from being reduced and required operation can quickly be executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] Specifically, the present invention relates to a heat fixing device suitable for coloring and glossing color development paper compatible with light and pressure sensitive paper as described in US Pat. No. 4,399,209. be.

[Prior Art] A conventional belt-type heat fixing device of this type is shown in FIG. 4. In this device, a belt 76 is wound around a heat roller 72 and a tensioning roller 77. The heat roller 72 is heated by a heater 74. A temperature detection sensor 75 constantly detects the temperature of the heat roller 72, and a temperature control circuit (not shown) keeps the temperature of the heat roller 72 constant.
4 is controlled. The nip roller 73 is pressed against the heat roller 72 with a constant force via a belt 76 by a pressure spring (not shown).

A color developer paper obtained by the predetermined image processing shown in the specification of U.S. Pat. ) and pressure is applied, the developer surface comes into close contact with the belt 76, and the developer paper adheres to the belt surface. The belt 76 is naturally cooled by heat radiation in the cooling section 78 . The binder polymer (binder resin) coated on the color developer paper is heated and then cooled to increase its viscosity, making the color developer paper easier to peel off from the belt surface. When the developer surface is sufficiently cooled (9
When the color developer paper reaches the tension roller 77 at a temperature of 0.6 to 100 °C, the color developer paper is stretched by the belt 7 due to its own elasticity.
The curvature is separated from 6.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional apparatus, if the developer paper reaches the tension roller 77 before the developer surface is sufficiently cooled, the developer paper may not separate from the belt 76. Even if separated, there is a problem that the color developer will be transferred to the belt 76.

Therefore, in order to increase the cooling effect on the surface of the color developer, it is conceivable to provide a cooling fan or the like in the belt cooling section 78 to actively cool the belt 76.

However, active cooling by the cooling fan 79 is necessary during the heat fixing process of the color developer paper, and the surface temperature of the belt 76 at the tension roller 77 portion is 100°C.
This occurs only when the temperature exceeds the temperature limit or when the set temperature of the heat roller 72 is being lowered. Conversely, if the cooling fan is operated for no reason at any other time, thermal efficiency will deteriorate. Moreover, if the cooling fan is activated during warm-up or during operations such as raising the set temperature of the heat roller, there is a problem in that the speed of each operation is unnecessarily slowed down.

The present invention was made to solve the above-mentioned problems, and by controlling the belt cooling device by comprehensively determining the belt temperature, warm-up time, etc., it reduces waste in terms of thermal efficiency. The purpose of the heat fixing device is to quickly perform the required operations.

[Means for Solving the Problems] In order to achieve this object, the present invention includes a heat roller,
A heat fixing device comprising a stretching roller, a belt hooked thereon, and a nip roller that presses against the heat roller via the belt, and heats the sheet while conveying the sheet by rotation of the belt, The apparatus includes a cooling means disposed opposite to a part of the belt located between the heat roller and the tensioning roller, and a control means for controlling driving and stopping of the cooling means.

Preferably, in the heat fixing device, the control means further includes a temperature sensor for detecting the temperature of the belt, and controls the cooling means based on the temperature detected by the temperature sensor. Alternatively, it is desirable to stop the operation of the cooling means during warm-up.

[Function] In the heat fixing device of the present invention having the above configuration, the cooling device is controlled based on the belt temperature or during warm-up, so the operation is efficient and necessary in terms of thermal efficiency. Do this promptly.

[Embodiment] Hereinafter, an embodiment of the present invention as a copying machine will be described with reference to the drawings.

The photosensitive pressure sensitive copying machine 1 of this embodiment uses photosensitive paper consisting of a photosensitive pressure sensitive paper (hereinafter referred to as microcapsule paper) 12 and a color developing paper 28.

Note that the microcapsule paper 12 used in this example
The surface of the support is coated with microcapsules, and the microcapsules contain dye precursors and the like that react with the color developer described below. A color developer is coated on the surface of the first color developer paper 28 and develops color by reacting with a dye precursor.
9, etc., and is not directly related to the present invention, so the explanation will be omitted.

As shown in FIG. 3, an original platen glass 2 and an original platen cover 3 are provided on the upper part of the copying machine 1.
A desired document 4 is placed face down on top of the document table cover 3, and the document table cover 3 is closed.

A halogen lamp 5a and a reflector 5b are provided below the document table glass 2 in the upper part of the copying machine 1.

5c, a light source section 5 equipped with a reflecting mirror 8, etc., is disposed so as to be movable back and forth along an axis 13 extending parallel to the document table glass 2. The light source unit 5 irradiates light onto the document table glass 2 on a line in a direction perpendicular to the movement direction. The irradiated light passes through the transparent document platen glass 2 and is reflected downward by the document 4 placed thereon.

A mirror portion 9 including reflective mirrors 9a and 9b is disposed below the document table glass 2 and is movable separately from the light source section 5, and the light reflected from the document 4 is reflected by the reflective mirrors 8.
The light beams 9a and 9b are reflected in this order and guided in parallel to the moving direction of the light source section 5.

A normally fixed projection lens 7 and a filter 6 for adjusting the color tone of the copied image are disposed below the document table glass 2, and the light reflected by the reflection mirror 9b is directed to the projection lens 7. incident.

The light projected by the lens 7 passes through a group of reflective mirrors 10
a, 10 reflected by b.

An exposure stage 11 for exposing the microcapsule paper 12 is disposed to the right of the reflective mirror 10b, and a reflective mirror 10c for switching the optical path is disposed between the reflective mirror 10b and the exposure stage 11. ing. Image information on the document 4 is formed on the microcapsule paper arranged along the exposure table 11.

In addition, although the reflecting mirrors 10a and 10b are normally located at predetermined positions, the optical path length can be changed according to the change in the projection magnification m that is set when enlarging or reducing the size of the latent image formed on the microcapsule paper 12. In order to change the shape, the structure is such that they can be moved together in the axial direction of the shaft 13.

On the other hand, a cartridge 15 that is removable from the machine body is disposed in the center of the copying machine 1, and a long microcapsule paper 12 is housed in the cartridge 15 while being wound around a cartridge shaft 14. There is. Cartridge 15
is set at a predetermined position inside the machine, the leading end of the microcapsule paper 12 is pulled out toward the exposure table 11. A feed roller 1 is provided below the exposure table 11.
9. A dancer roller 21 for tension adjustment is provided. A pressure developing device 22 including a large diameter roller 22a and a backup roller 22b is disposed to the right of the dancer roller 21.

A separation roller 23 is provided on the right side of the pressure developing device 22 to separate the microcapsule paper 12 and the color developing paper 28 which are in close contact with each other as will be described later. A winding shaft 24 for fitting and holding the microcapsule paper 12 is disposed between the separation roller 23 and the cartridge 15. The microcapsule paper 12 that comes out from the top of the cartridge 15 is guided by a feed roller 19 to the exposure stage 1.
After passing above 1, it passes through a dancer roller 21, a pressure developing device 22, and is further led to a separation roller 23.
It is wound up on the winding shaft 24. Note that the unexposed microcapsule paper 12 after leaving the cartridge 15 is maintained in an unexposed state by the light shielding cover.

A paper feed cassette 29 containing developer paper 28 is installed below the pressure developing device 22 . The paper cassette 2
A suction cup type paper feeding mechanism 30 that sucks paper using negative pressure suction is disposed above the paper feeding mechanism 9, and the developing paper 28 is taken out one by one from the paper feeding cassette 29 by the paper feeding mechanism 30. A feed guide 31d, feed rollers 31a, 81b, and 31c are arranged between the paper feeding mechanism 30 and the pressure developing device 22, and the color developing paper 28 is placed between the feed rollers 31a and 31b.
31C, and is conveyed by a feed guide 31d and carried into the pressure developing device 22.

A heat fixing device 32 is disposed to the right of the pressure developing device 22, and a paper discharge tray 33 for storing the developer paper 28 on which an image is formed is disposed to the right of the heat fixing device 32. There is.

Furthermore, this copying machine has an autoloading function for automatically setting the microcapsule paper 12 on a predetermined transport path within the apparatus.

This is a function in which the leader film portion attached to the tip end of the microcapsule paper 12 is pulled out into the device by a mechanical force, conveyed through the device, and wound around the winding shaft 24. Thereby, the microcapsule paper 12 following the leader film section 18 is also wound up on the winding shaft 24, and the setting into the apparatus is completed. For this automatic loading, a half-moon roller 17 is provided between the roller 19 and the cartridge 15 for pulling out the leader film section. Further, a separation chute 27 is rotatably attached to guide the winding shaft 24 to the winding shaft 24. An upper winding guide 25 and a lower winding guide 26 are arranged around the winding shaft 24 for winding the leader film.

Next, the heat fixing device 32 will be explained in detail.

As shown in FIG. 1, the heat roller 40
It is rotatably supported around a horizontal axis above the transport path 8, and a heater 41 made of a halogen lamp or the like is provided inside. A thermistor 42 is disposed near the heat roller 40, and under the control of the thermistor 42, the heat roller 4 is heated by the heater 41.
The surface temperature of 0 is maintained at about 150°C.

The stretching roller 43 is rotatably supported above the conveyance path of the color developing paper 28 around an axis parallel to the heat roller 40, and an endless belt 44 is provided between both rollers 40 and 43.
is hung. When the heat roller 40 is rotated counterclockwise in FIG. 1 by a drive motor (not shown) via a gear mechanism or the like, the belt 44 is rotated in the same direction and the developer paper 28 is conveyed.

The nip roller 45 is pressed against the outer peripheral lower surface of the heat roller 40 by a spring (not shown), and a predetermined nip pressure is applied to a portion of the belt 44.

Furthermore, a cooling fan 46 for cooling the belt is installed below the belt 44 located between the heat roller 40 and the tensioning roller 43 and facing the belt 44 . This cooling fan 46 can actively lower the temperature at the belt 44 and the sheet tensioning roller 43 when they are separated.

Furthermore, a temperature sensor 47 is provided on the lower surface of the outer periphery of the tensioning roller 43.
is installed to detect the surface temperature of the belt 44 passing through this portion.

The material of the belt 44 may include silicone rubber alone, metals such as stainless steel or nickel, or a base film of heat-resistant resin such as polyimide or PPS coated with silicone rubber. can.

Next, the operation of the present copying machine 1 will be explained.

When the cartridge 15 is set in the copying machine 1, autoloading is started.

The half-moon roller 17 rotates once to several times in the conveyance direction only when autoloading starts, and the leader film section 18
is sent out to roller 20. Thereafter, it stops, and subsequent conveyance is performed by driving the rollers 20.

The upper winding guide 25, the lower winding guide 26, and the separation chute 27 are rotated to the positions shown by the - dotted chain line, and the leader film section 18 attached to the tip of the microcapsule paper 12 is automatically wound around the winding shaft 24. When loading is completed, the upper winding guide 25, the lower winding guide 26,
It returns to the separation chute 27 or the position shown by the solid line and can be copied.

When a copy start key (not shown) provided on the front panel 6o, which will be described later, is pressed, the halogen lamp 5a is turned on, and the reflecting mirror 8 and the halogen lamp 5a change the transport speed of the microcapsule paper 12 to a projection magnification of v1. Assuming that m is the moving speed, the reflecting mirror 9a19b moves at a moving speed of 1/2 mV and starts document scanning.

The conveyance speed of the microcapsule paper 12 is determined by the mirror group 8.9a.
, 9b is synchronized as described above,
Latent images of predetermined lines of the document 4 are sequentially formed on the microcapsule paper 12 as it passes through the exposure stage 11 . Note that the predetermined speed ratio is predetermined based on the setting of the magnification.

The microcapsule paper 12 on which the latent image has been formed is transported,
The topmost color developing paper 28 of the paper feed cassette 29 is fed to the paper feed mechanism 30.
．． It is conveyed by feed rollers 31a, 31b, 310, etc.

The pressure developing device 22 is supplied with the microcapsule paper 12 and the color developer paper 28 in close contact with each other, and the microcapsule surface on which the latent image of the microcapsule paper 12 is formed and the color developer of the color developer paper 28. The application surface is integrally sandwiched between the large diameter roller 22a and the backup roller 22b in a state in which they are in contact with each other on the inside, and pressure is applied. This pressure destroys the unexposed microcapsule paper, and the developer paper 28
An image is formed on top.

The microcapsule paper 12 and the color developer paper 28 that have come out of the pressure development device 22 are separated by a separation roller 23, and then the color development of the color developer paper 28 is promoted by the heat fixing device 32, and a glossy image is formed. Thereafter, the paper is delivered to the paper ejection tray 33 by the paper ejection roller 32b. Note that the separated microcapsule paper 12 is wound up on a winding shaft 24 via a separation roller 23e.

Next, the operation of the heat fixing device 32 will be explained.

Immediately after the power is turned on, the heater 41 is energized to perform a warm-up operation, that is, to heat the heat roller 40 to a predetermined temperature until the copying machine 1 is ready for copying operation. When this warm-up operation is completed, the heat roller 40 is maintained at about 150° C. and rotated, and the nip roller 45 and belt 44 are maintained at appropriate temperatures. Developing paper 2 with an image formed on its surface in this state
8 is inserted into the heat fixing device, while being pressed against the belt 44, it is heated by the heat of the heater 41 via the heat roller 40 and the belt 44, and the color developer on the color developer paper 28 is melted.

Therefore, the developer paper 28 sticks to the lower running portion of the belt 44 and is heated and fixed while being conveyed as the belt 44 rotates. If the belt 44 and the color developer paper 28 are sufficiently cooled while the color developer paper 28 is conveyed to the position corresponding to the tension roller 43, the color developer paper 28 will be transferred to the belt due to the curvature of the tension roller 43. Separate from 44.

However, if the temperature at which the color developer paper 28 and the belt 44 are separated is not lowered sufficiently, the two may continue to rotate without being separated, or the color developer on the color developer paper 28 may continue to rotate even after separation. It may adhere to the belt 44 (offset phenomenon), or a number of striped patterns may appear on the image surface in a direction perpendicular to the direction in which the color developer paper 28 is conveyed. In either case, the main cause is that the viscosity of the color developer is not sufficiently increased. The separation temperature at which the color developer paper 28 and the belt 44 are reliably separated varies depending on the material of the belt 44 and the type of color developer paper to be processed, and is around 1000C.

Therefore, the separation temperature between the belt 44 and the color developing paper 28 is 10
Cooling fan 4 is installed to prevent the temperature from exceeding 0℃.
6, and plays the role of air cooling the lower surface of the belt 44 as shown in FIG.

However, it is not preferable to keep the cooling fan 46 operating all the time. This is because there are times when the separation temperature does not exceed 100° C. even if the cooling fan 46 is not used for forced cooling. In this case, the cooling fan 46 merely dissipates the heat of the belt 44 into the air, which is poor in terms of thermal efficiency. The heat roller 40 is a factor that determines the separation temperature when the cooling fan 46 is not operating.
temperature setting, rotation speed of the belt 44, environmental temperature, etc.

Other cases in which it is better not to operate the cooling fan 46 are during a warm-up operation or when a heat fixing process is not being performed.

If the cooling fan 46 is operated during warm-up operation, the warm-up time will become longer. Moreover, operating the cooling fan 46 when the heat fixing process is not being performed is still bad in terms of thermal efficiency.

However, there are cases where it is better to operate the cooling fan 46 even when the heat fixing process is not being performed.

This is a case where the temperature setting of the heat roller 40 is lowered to a low temperature side, and by forcibly cooling the belt 44 with the cooling fan 46, the temperature of the heat roller 40 can be quickly lowered.

As described above, the decision as to whether or not to operate the cooling fan 46 depends on the situation in which the heat fixing device is placed (during warm-up, standby, changing the temperature setting of the heat roller, and during heat fixing processing). Further, during the heat fixing process, it is necessary to make a comprehensive judgment after detecting whether the separation temperature exceeds 100°C.

FIG. 2 is a block diagram showing a control mechanism of the thermal fixing device 32 including the cooling fan 46. As shown in FIG. The control device 50 is a CPU, R
It is generally composed of OM, RAM, etc. The control device 50 includes a front panel 60, a thermistor 42,
Receiving a signal from the pressure developing device 22 etc., the situation judgment control section 5
1, the state in which the heat fixing device 32 is placed (during warm-up, standby, heat fixing processing, etc.) is determined, and the heat roller drive motor 61, heater 41. Controls the cooling fan 46. The situation judgment control section 51 includes a warm-up section 5
2. Heat roller temperature setting up section 53, heat roller temperature setting town section 54, special equipment section 55, heat fixing processing section 56
, is equipped with. The heat fixing processing section 56 includes a temperature determining section 57,
It is connected to the cooling fan 46 via a temperature check section 58. A discrimination sensor 62 and a front panel 60 are connected to the temperature determination section 57 . In addition, the temperature check section 5
8 is connected to a temperature sensor 47.

When the temperature of the heat roller 40 has not reached the set value immediately after the power is turned on (that is, during warm-up operation), the warm-up section 52 energizes the heater 41 and motor 61 to perform warm-up operation, but stops the cooling fan 46. I'll let you. Further, even when the power is turned on but the copying operation is not performed and the copying operation is on standby, the special equipment section 55 similarly stops the cooling fan 46.

However, even during standby, if the set temperature of the heater 41 is lowered by a command from the front panel 60, the heat roller temperature setting down section 54 drives the cooling fan 46 to forcibly cool the belt 44. This allows the temperature of the heat roller 40 to be lowered quickly.

Conversely, when increasing the set temperature of the heater 41, the heat roller temperature setting up section 53a and the cooling fan 46 are stopped.

When performing heat fixing on the pressure-developed color developer paper 28, the heat fixing processing section 56 first causes the temperature determining section 57 to set the temperature at the time of separation according to the type of the color developer paper 28 to be processed. This is because the allowable temperature value during separation differs slightly depending on the type of base material coated with the color developer of the color developer paper 28 to be processed. The type of color developing paper 28 is recognized by a command from a discrimination sensor 62 or a front panel 60.

The temperature at the time of separation is determined by the temperature determination unit 57, and the temperature check unit 58 receives a signal from the temperature sensor 47 measuring the temperature at the time of separation, and the temperature at the time of separation is determined by the temperature determination unit 57. Check that the temperature has not exceeded the specified temperature. Here, if the temperature measured by the temperature sensor 47 exceeds the determined temperature, the cooling fan 46 is activated, and if it does not exceed the determined temperature, the cooling fan 46 is stopped. Of course, during the heat fixing process, the temperature at the time of separation is constantly detected, and if the temperature is about to exceed the allowable temperature, the cooling fan 46 is immediately activated.

It should be noted that the present invention is not limited to the above-described cooling configuration, and may be modified and embodied without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the detailed description above, the present invention includes a cooling device for the belt and a control device for stopping and controlling the operation of the cooling device, and controls the temperature of the belt and heat fixing. By controlling the cooling device based on the situation in which the device is placed, it is possible to perform necessary operations such as warm-up quickly without wasting any waste in terms of thermal efficiency.

[Brief explanation of the drawing]

1 to 4 show an embodiment embodying the present invention, FIG. 1 is a sectional view showing an embodiment of a heat fixing device embodying the present invention, and FIG. 2 is a heat fixing device embodying the present invention. FIG. 3 is a schematic configuration diagram of a copying machine using a heat fixing device embodying the present invention, and FIG. 4 is a sectional view showing a conventional heat fixing device. In the figure, 28 is a developing paper, 40 is a heat roller, 43 is a tensioning roller, 44 is a belt, 45 is a nip roller, 46 is a cooling fan, 47 is a temperature sensor, and 50 is a control device.

Claims (1)

[Scope of Claims] 1. A heat roller, a tensioning roller, a belt hooked around both rollers, and a nip roller that presses against the heat roller via the belt; In a heat fixing device that heats while conveying the heat roller, the cooling means is arranged to face a part of the belt located between the heat roller and the stretching roller, and the cooling means is controlled to drive and stop. A heat fixing device comprising a control means. 2. The control means has a temperature sensor that detects the temperature of the belt, and controls the cooling means based on the temperature detected by the temperature sensor. Heat fixing device. 3. The heat fixing device according to claim 1, wherein the control means stops driving the cooling means during warm-up.