JPH05297749A - Fixing device - Google Patents

Abstract

PURPOSE:To provide a fixing device in which a recording paper is prevented from getting wrinkled. CONSTITUTION:This device is a fixing device which is provided with a pressure roller 2 opposingly arranged so as to press-contact with a fixing roller 1 having a heat source 1a, and a fixing roller temperature sensor 5 detecting the surface temperature of the fixing roller, and which fixes an image on the recording paper 4 passing between the fixing roller and the pressure roller. It is provided with a controller 9 which controls power supplied to the heat source 1a based on the surface temperature of the pressure roller detected by a pressure roller temperature sensor 8 detecting the surface temperature of the pressure roller and the surface temperature of the fixing roller detected by the sensor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in electrophotographic printers and copying machines. In particular, the present invention relates to a fixing device in which wrinkles do not occur on recording paper.

[0002]

2. Description of the Related Art The basic structure of a conventional fixing device is shown in FIG.

In FIGS. 1A and 1B, reference numeral 1 is a metal fixing roller. The fixing roller 1 is hollow and has a heat source 1a inside. Reference numeral 2 denotes a pressure roller made of an elastic body, which is arranged so as to face the fixing roller 1,
It is pressed against the fixing roller 1 by the spring 3. Reference numeral 2a is a cored bar, and 2b is a shaft integrally formed with the cored bar 2a.

A fixing roller temperature sensor 5 is provided near the surface of the fixing roller 1. The fixing roller temperature sensor 5 is
The surface temperature of the fixing roller 1 is detected, and the detection signal is sent to the controller 6 as shown in FIG. The controller 6 controls the heat source drive circuit 7 based on the surface temperature of the fixing roller 1 detected by the fixing roller temperature sensor 5, and controls the electric power supplied to the heat source 1a.

The recording paper 4 on which an image is formed in the preceding step is provided between the fixing roller 1 and the pressure roller 2 of such a fixing device.
The recording paper 4 passes through the fixing roller 1 and the pressure roller 2.
The image is fixed on the recording paper 4 by being heated while being pinched by and.

If the heat applied to the recording paper 4 is improper, image fixing failure or wrinkles may occur on the recording paper. Therefore, the controller 6 controls the heat applied to the recording paper 4 to be appropriate. The electric power supplied to the heat source 1a is controlled.

[0007]

In the above-mentioned conventional fixing device, management of heat applied to the recording paper 4 was insufficient.

That is, for example, when printing is continuously performed on a large number of recording papers 4, the fixing device also operates continuously, and the temperature of the pressure roller 2 also rises. Therefore, in such a case, the recording paper 4 is also heated by the pressure roller 2.

In the conventional fixing device, only the surface temperature of the fixing roller 1 is detected and the electric power supplied to the heat source 1a is controlled based on the detected temperature only. There is a problem that the recording paper 4 cannot be prevented from being overheated and, as a result, the recording paper 4 is wrinkled.

An object of the present invention is to solve the above problems and to provide a fixing device in which wrinkles do not occur on the recording paper.

[0011]

In order to achieve the above object, the present invention provides a fixing roller having a heat source, a pressure roller arranged in pressure contact with the fixing roller, and a surface temperature of the fixing roller. And a fixing roller temperature sensor for detecting the temperature of the pressure roller, and a fixing roller temperature sensor for detecting the surface temperature of the pressure roller in a fixing device for fixing an image on the recording paper passing between the fixing roller and the pressure roller. And a controller for controlling the electric power supplied to the heat source based on the surface temperature of the pressure roller detected by the pressure roller temperature sensor and the surface temperature of the fixing roller detected by the fixing roller temperature sensor. It is characterized by

[0012]

Since the fixing device of the present invention has the above-mentioned structure, it operates as follows.

The surface temperature of the fixing roller is detected by the fixing roller temperature sensor, and the surface temperature of the pressure roller is also detected by the pressure roller temperature sensor.

The controller controls the electric power supplied to the heat source based on the surface temperature of the pressure roller and the surface temperature of the fixing roller detected by these sensors.

That is, the electric power supplied to the heat source is controlled not only by the surface temperature of the fixing roller but also by the surface temperature of the pressure roller.

Therefore, according to the fixing device of the present invention, even when the temperature of the pressure roller rises due to continuous operation or the like,
It is possible to prevent overheating of the recording paper by the heating roller, and as a result, it is possible to prevent the recording paper from wrinkling.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a front view showing a first embodiment of a fixing device according to the present invention. The same parts as those of the conventional device shown in FIG. 9 are designated by the same reference numerals. ..

The feature of this embodiment is that the pressure roller temperature sensor 8 is used.
Is provided near the surface of the pressure roller 2. The pressure roller temperature sensor 8 is composed of, for example, a thermistor or the like like the fixing roller temperature sensor 5, detects the surface temperature of the pressure roller 2, and sends the detection signal to the controller 9 as shown in FIG. The controller 9 controls the heat source drive circuit 7 based on the surface temperature of the fixing roller 1 detected by the fixing roller temperature sensor 5 and the surface temperature of the pressure roller 2 detected by the pressure roller temperature sensor 8, and the heat source 1a. It is designed to control the power supplied to.

According to the fixing device having such a structure, the surface temperature of the fixing roller 1 is detected by the fixing roller temperature sensor 5, and the surface temperature of the pressure roller 2 is also detected by the pressure roller temperature sensor 8.

The controller 9 controls the electric power supplied to the heat source 1a based on the surface temperature of the pressure roller 2 and the surface temperature of the fixing roller 1 detected by these sensors 5 and 8. That is, the electric power supplied to the heat source 1 a is controlled not only by the surface temperature of the fixing roller 1 but also by the surface temperature of the pressure roller 2.

Therefore, according to such a fixing device,
Even if the temperature of the pressure roller 2 rises due to continuous operation or the like, overheating of the recording paper 4 by the heating roller 2 can be prevented, and wrinkles can be prevented from occurring on the recording paper 4.

<Second Embodiment> FIG. 2 is a front view showing a second embodiment of the fixing device according to the present invention.

The feature of this embodiment lies in the constitution of the pressure roller 20, and the other constitution is the same as that of the above-mentioned first embodiment.

The pressure roller 20 has elastic bodies 22, 23, 24 sequentially arranged on both sides of an elastic body 21 arranged in the center thereof, and these elastic bodies are all joined to form one roller. is there. The elastic body 21 is made of a material having a relatively small frictional resistance, and the elastic body 2 is arranged toward both ends.
2, 23 and 24 are made of a material whose frictional resistance increases in sequence. That is, the elastic body 22 has a larger frictional resistance than the elastic body 21, the elastic body 23 has a larger frictional resistance than the elastic body 22, and the elastic body 24 has a larger frictional resistance than the elastic body 23. ing.

The fixing device of this embodiment operates as follows.

FIG. 3 is a view taken along the line III-III in FIG. 2, where N indicates the contact surface between the fixing roller 1 and the pressure roller 20. Further, 41 to 44 are elastic bodies 2 respectively.
The area | region of the paper 4 pressed by 1-24 is shown.

The recording paper 4 passing between the fixing roller 1 and the pressure roller 20 has its central portion 41 conveyed by a comparatively small conveying force f1 by an elastic body 21 having a comparatively small frictional resistance, and both end portions thereof. Area 41, 42, 4
The elastic members 22, 23, and 24, whose frictional resistances are successively increased, are transported by the transporting forces f2, f3, and f4. Since the fixing roller 1 has a gently curved drum shape, the paper 4 is conveyed outward as it goes to both ends 4a, 4a, and is conveyed in a state where both ends are pulled outward. Becomes

Therefore, according to such a fixing device,
In addition to the heat management of the heating roller 20, wrinkles are less likely to occur.

As shown in FIG. 4, the pressure roller 30
Is composed of one kind of elastic body, and is divided into a central portion 31 and regions 32, 33, 34 extending from the central portion 31 to both ends, and a predetermined number of thrust direction notches 35 are made in the region 32 to form the region 33. The same action and effect can be obtained by making a larger number of cuts 35 in the region 34 than in the region 32 and making a larger number of cuts 35 in the region 34. As shown in FIG. 3B, the cut 35 serves to increase the frictional resistance to the recording paper 4 by opening the contact portion 36 with the recording paper 4 by the rotation operation of the pressure roller 30 in the direction of the arrow a. Is to fulfill.

<Third Embodiment> FIG. 5 is a schematic perspective view showing a third embodiment of the fixing device according to the present invention, and FIG. 6 is a partially enlarged perspective view.

The feature of this embodiment lies in the constitution of the pressure roller 40, and the other constitution is the same as that of the first embodiment described above.

On the surface 41 of the pressure roller 40, heat-resistant fibers (for example, glass fibers) 42 are provided along the thrust direction S as shown in FIG.

With this structure, when the recording paper passes between the fixing roller 1 and the pressure roller 40, the frictional resistance of the pressure roller 40 to the recording paper is in the radial direction R (that is, the recording paper is conveyed). Direction) and decreases in thrust direction S.

Therefore, a sufficient conveying force for the recording paper can be obtained, and the recording paper can easily slide in the thrust direction S and the recording paper can easily spread in the thrust direction S.

Therefore, according to such a fixing device,
In addition to the heat management of the heating roller 40, wrinkles are less likely to occur.

Further, as shown in FIG. 7, the heat resistant fiber 42
Even if the notch 43 is provided instead of providing the same, the same effect can be obtained. The heat resistant fiber 42 or the cut 4
For example, as shown in FIG. 8, 3 may be provided over the entire length in the thrust direction. Further, the heat resistant fibers and the cuts may be alternately provided in the radial direction and / or the thrust direction.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention.

[0039]

According to the present invention, since the electric power supplied to the heat source is controlled not only by the surface temperature of the fixing roller but also by the surface temperature of the pressure roller, overheating of the recording paper by the heating roller is prevented. As a result, it is possible to prevent wrinkles from occurring on the recording paper.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a fixing device according to the present invention,
(A) is a front view, (b) is a bb sectional view in (a), and (c) is a block diagram.

FIG. 2 is a front view showing a second embodiment of the fixing device according to the present invention.

FIG. 3 is an explanatory view of the same as above.

4A and 4B are views showing a modified example of the same pressure roller, in which FIG. 4A is a front view and FIG.

FIG. 5 is a schematic perspective view showing a third embodiment of the fixing device according to the present invention.

FIG. 6 is a partially enlarged cutaway perspective view of the same.

FIG. 7 is a partially enlarged perspective view showing a modified example of the same pressure roller.

FIG. 8 is a front view showing a modified example of the same pressure roller.

FIG. 9 is a view showing a conventional fixing device, (a) is a front view,
(B) is a sectional view taken along line bb in (a), and (c) is a block diagram.

[Explanation of symbols]

 1 Fixing Roller 1a Heat Source 2 Pressure Roller 5 Fixing Roller Temperature Sensor 8 Pressure Roller Temperature Sensor 9 Controller

Claims (1)

[Claims] 1. A fixing roller comprising a fixing roller having a heat source, a pressure roller arranged in pressure contact with the fixing roller, and a fixing roller temperature sensor for detecting a surface temperature of the fixing roller. In a fixing device for fixing an image on the recording paper passing between the pressure roller and a pressure roller, a pressure roller temperature sensor for detecting the surface temperature of the pressure roller and a pressure roller detected by the pressure roller temperature sensor And a controller that controls electric power supplied to the heat source based on a surface temperature and a surface temperature of the fixing roller detected by the fixing roller temperature sensor.