JPH03220555A - Heat fixing device - Google Patents

Abstract

PURPOSE:To obtain the heat fixing device which is safe and highly reliable with an easy control method by rotating a fan for deodorization when a temp. detecting means detects that the temp. of a heating roller attains a set temp. or the prescribed temp. near the set temp. CONSTITUTION:The heat roller 32a is heated by a heat fixing heater 34 and the temp. thereof rises. The heater 34 is de-energized and the fan 38 for deodorization is driven when the temp. of the roller 32a is decided to be above the set temp. Although the temp. of the roller 32a overshoots at this time, the fan 38 is kept driven and, therefore, the roller 32a is cooled and the temp. thereof falls rapidly. The fan 38 is kept driven in succession until the temp. of the roller 32a attains the set temp. (130 deg.C). There is no need for providing the fan to be exclusively used in this way and the heat fixing device of the simple constitution is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal fixing device for thermally fixing an image onto paper in an image forming apparatus such as a copying machine.

[Prior art] Conventionally, for example, temperature control at the time of starting energization of the heating roller is similar to the normal temperature control of the heating roller. When the current temperature is lower than the set temperature, the heater is turned on and the current temperature becomes the set temperature. When the temperature was higher, the heater was turned off.

Alternatively, by checking the temperature rise rate based on the currently detected temperature and the previously detected temperature, the temperature at the next point in time can be predicted and calculated, and based on the calculation results, the heater can be adjusted to prevent the temperature from rising rapidly. Some controlled the start-up of the system.

[Problems to be Solved by the Invention] However, in the former conventional control method, a temperature difference occurs between the back surface of the roller and the surface of the roller on the heat source side due to the heat capacity of the heating roller, especially when starting heating. , an overshoot phenomenon occurs in which the temperature of the heater greatly exceeds the set temperature even if the power to the heat source of the heater is cut off after reaching the set temperature (curve indicated by A in Figure 4). There was a problem in that it took time for the shot temperature to return to the set temperature, and it took time for the device to start up. Furthermore, depending on the material or size of the heating roller, the overshoot temperature may become excessively high, resulting in problems such as deformation of the device.

In addition, in the conventional latter control method, the amount of current to be applied to the heater is calculated and controlled based on the rate of temperature rise, so there is no overshoot, but the temperature rise is done slowly to avoid overshoot (the fourth (Curve shown as B in the diagram), it takes time to reach the set temperature, and it takes time for the device to start up.Furthermore, such calculations are performed to predict the temperature, and the amount of current to the heater is There is also a problem in that the control mechanism complicates the control mechanism.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a safe and highly reliable heat fixing device using a simple control method.

[Means for Solving the Problems] In order to achieve this object, the heat fixing device of the present invention includes a heat source inside and a heating roller for heating and fixing the image on the paper to the paper using the heat from the heat source. a deodorizing fan for guiding gas generated when the paper is heated by the heating roller to a deodorizing filter; a temperature detecting means for detecting the temperature of the heating roller; and a temperature detected by the temperature detecting means. Temperature control means for controlling the temperature of the heating device to a certain set temperature based on the temperature,
The deodorizing fan is rotated when the temperature detecting means detects the set temperature or a temperature near the set temperature after the heating roller starts heating.

[Function] In the heat fixing device of the present invention having the above configuration, when the temperature detection means detects that the temperature of the heating roller has reached the set temperature or a predetermined temperature near the set temperature when the heater is heating, Turn on the deodorizing fan.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

FIG. 1 shows a photosensitive and pressure sensitive copying machine equipped with a heat fixing device of the present invention.

In the photosensitive and pressure sensitive copying machine l of this embodiment, as shown in FIG.
and color developer paper 28 (hereinafter referred to as recording paper) are used.

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 support of the color developer paper 28, and develops color by reacting with a dye precursor.
399209 specification, etc., and will be omitted here.

At the top of the copying machine 1, there is a document table glass 2 and a document table cover 3.
A desired original 4 is placed on the original platen glass 2.
is placed face down 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.

A light source unit 5 equipped with a reflecting mirror 8 and the like is disposed so as to be movable back and forth along a shaft 13 extending parallel to the document table glass 2. The light source section 5 irradiates light onto the document table glass 2 in 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 and 10b.

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 original fA4 is formed on the microcapsule paper arranged along the exposure table 11.

In addition, the reflecting mirrors 10a and 10b are normally fixed, but are set when enlarging or reducing the size of the latent image formed on the microcapsule paper 12, and change the optical path length according to a change in the projection magnification m. Therefore, they are configured to be able to move together in the axial direction of the shaft 13.

On the other hand, a cartridge 15 is disposed in the center of the copying machine 1, and the elongated microcapsule paper 12 is housed in the cartridge 15, which is removable from the machine while being wound around the cartridge shaft 14. With the cartridge 15 set at a predetermined position within the machine, the leading end of the microcapsule paper 12 is pulled out toward the exposure table 11. Below the exposure table 11 is a feed roller 19,
A dancer roller 21 for tension adjustment is provided. To the right of the dancer roller 21 is a large diameter roller 2.
2a and a backup roller 22b is disposed, and on the right side of the pressure developing device 22, there is a microcapsule paper 12 closely attached as will be described later.
A separation roller 23 is provided to separate the microcapsule paper 28 from the microcapsule paper 28, and a take-up shaft 24 for inserting and holding the microcapsule paper 12 is provided between the separation roller 23 and the cartridge 15. There is. The microcapsule paper 12 that comes out from the top of the cartridge 15 is transferred to the tension roller 1
9, passes above the exposure table 11, passes through a dancer roller 21, a pressure developing device 22, is further guided to a separating roller 23, and is then wound onto a 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 .

A suction cup type paper feeding mechanism 30 that sucks paper using negative pressure suction is arranged above the paper feeding cassette 29, and the developing paper 28 is taken out one by one by the paper feeding mechanism 30. A feed guide 31d1 and feed rollers 31a, 31b, and 31c are disposed between the paper feeding mechanism 30 and the pressure developing device 22, and the developer paper 28 is fed by the feed rollers 31a, 31b, and 31c.
31c.

It is conveyed by the 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. has been done. A deodorizing filter 37 for removing the odor of gas generated during heat fixing and a deodorizing fan 38 for guiding the gas to the deodorizing filter 37 are disposed above the thermal fixing device 32.

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 that automatically pulls out the leader film portion attached to the tip of the microcapsule paper 12 into the apparatus, transports it within the apparatus, and winds it around the winding shaft 24. As a result, the microcapsule paper 12 following the leader film section 18 is also wound up on the winding shaft 24, and the setting in 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, and a take-up shaft 24 is provided between the roller 19 and the cartridge 15.
A separation chute 27 is rotatably attached to guide the user. Around the winding shaft 24, a machining guide 25 and a machining guide 26 are arranged for winding the leader film.

Next, the operation of this copying machine 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 machini guide urchin 25, the makitri guide sitter 26, and the separation chute 27 rotate to the position shown by the - dotted chain line, and the leader film part 18 attached to the tip of the microcapsule paper 12 is attached to the winding shaft 24. When the winding auto-loading is completed, Makitori Guide Uni 25,
The machining guide seat 26 and the separation chute 27 return to the positions indicated by solid lines and copying is possible.

When the copy start key is operated, the reflection mirror 8
, the halogen lamp 5 has a moving speed of 1/m when the transport speed of the microcapsule paper 12 is v1 and the projection magnification is m.
The reflecting mirrors 9a and 9b move at a speed of 1/
Moves at 2 mV.

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.
, conveying rollers 31a, 31b, 31c, 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 2
An image is formed on 8.

The microcapsule paper 12 and the color developer paper 28 that have come out of the pressure developing 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 roller 32a of the heat fixing device 32 to form an image. After that, the paper ejection roller 32b
The paper is carried out to the paper discharge tray 33 by the paper discharge tray 33. Note that the separated microcapsule paper 12 is wound up on the winding shaft 24 via the separation roller 23e.

Next, the electrical configuration of this embodiment will be explained with reference to FIG.

That is, the control bag rI 139 controls the energization of the heat fixing heater 34 and the deodorizing fan 38 built in the heat roller 32a of the heat fixing device 32. In addition, the heat roller 32
The output of a temperature detector 35 such as a thermistor provided near point a is input to a control device 39.

In the apparatus configured as described above, a method of controlling the temperature of the heat fixing device will be described with reference to FIG.

That is, when the power is turned on, the control device 39 first detects the temperature of the heat roller 32a with the temperature detector 35 (Step 1), and determines whether the detected temperature is 80° C. or higher (Step 2). . As a result of this determination, if the temperature at the start is 80° C. or higher, normal temperature control in steps 3 to 6 is executed. That is, depending on whether the temperature of the heat roller 32g detected by the temperature detector 35 is equal to or higher than the set temperature (130° C.), the energization state of the heat fixing heater 34 is controlled to maintain the temperature of the heat roller 32a at the set temperature.

On the other hand, if the temperature at the start is 80° C. or lower, the temperature of the heat roller 32a is detected in step 7. Then, it is determined whether the detected temperature is higher than the set temperature (130° C.) (step 8), and if the heat roller 32a has not reached the set temperature, the heat fixing heater 34 is energized (step 9), and , steps 7 to 9 are executed until the heat roller 32a reaches the set temperature.

On the other hand, when the heat roller 32a is heated by the heat fixing heater 34 and its temperature rises, and it is determined in step 8 that the temperature of the heat roller 32a is equal to or higher than the set temperature, the heat roller 32a is heated by the heat fixing heater 34 in step 10. The deodorizing fan 3 is stopped in step 19.
8 is driven. At this time, the temperature of the heat roller 32a overshoots, but since the deodorizing fan 38 is being driven, the heat roller 32a is cooled and its temperature drops rapidly (curve shown by C in FIG. 4). and,
Steps 12 and 13 are executed until the temperature of the heat roller 32a reaches the set temperature (130°C), and the deodorizing fan 38 continues to be driven.

When the temperature of the heat roller 32a reaches the set temperature, the heat fixing heater 34 is energized again in step 14, and the operation of the deodorizing fan 38 is stopped in step 15. Thereafter, the normal temperature control of steps 3 to 6 described above is executed, and the heat roller 32
a is maintained at a set temperature (130°C).

As described above, in this embodiment, when the power is turned on, or when power is turned on again to the heat fixing heater after the power supply to the heat fixing heater is stopped for a long time due to paper jam, etc. Even if the power supply to the fixing heater 34 is immediately stopped after the heat roller 32a reaches the set temperature, the temperature of the heat roller 32a will overshoot.

However, at this time, since the deodorizing fan 38 is driven at the same time as the power supply to the fixing heater 34 is stopped, the heat roller 32a is rapidly cooled down. For this reason, the heat roller 3
The overshoot condition of 2a is eliminated in a short time, and the device can be started up in a short time.

Note that this embodiment is not limited to the embodiment detailed above; for example, the timing for turning on the deodorizing fan was not when the set temperature was reached, but when the temperature was slightly lower than the set temperature, such as when the temperature was 125°C. The deodorizing fan may be turned off in various ways without departing from the scope of the claims, such as turning off the deodorizing fan not when the temperature returns to the set temperature but after a predetermined period of time has elapsed since the deodorizing fan was turned on. Improvements are possible.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention, the deodorizing fan is turned on when the temperature of the heat roller reaches the set temperature during start-up control of the heat fixing heater. The overshoot phenomenon that occurs at startup can be reduced, the time it takes to stabilize at the set temperature is shortened, and the warm-up time of the device is shortened. Furthermore, since the temperature rise due to overshoot can be reduced, the device will not be damaged or deformed due to high temperatures. Furthermore, since a deodorizing fan is used as a method for reducing overshoot, there is no need to provide a dedicated fan, and a heat fixing device with an inexpensive and simple configuration can be provided.

[Brief explanation of drawings]

1 to 5 show embodiments embodying the present invention. FIG. 1 is an overall schematic diagram of a copying machine equipped with the heat fixing device of the present invention, and FIG. 2 is a heat fixing device. FIG. 3 is a block diagram showing the electrical configuration; FIG. 4 is a graph showing changes in temperature at startup of the heat fixing device of the present invention and other conventional heat fixing devices; FIG. FIG. 5 is a diagram showing a control flowchart. In the figure, 32 is a heat fixing device, 32a is a heat roller, 34 is a heat fixer, 35 is a temperature detector, 37 is a deodorizing filter, 38 is a deodorizing fan, and 39 is a control circuit.

Claims (1)

[Claims] 1. A heating roller that has an internal heat source and heats and fixes the image on the paper using the heat from the heat source, and guides the gas generated when the paper is heated by the heating roller to a deodorizing filter. A deodorizing fan for
a temperature detecting means for detecting the temperature of the heating roller; and a temperature controlling means for controlling the temperature of the heating roller to a certain set temperature based on the temperature read by the temperature detecting means, and after the heating roller starts heating. A heat fixing device characterized in that the deodorizing fan is rotated when the temperature detecting means detects the set temperature or a temperature near the set temperature.