JPH103228A - Fixing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the fixing efficiency by reducing standby time and power consumption until a set mode reaches a set temperature, and also to prevent paper or the like on the surface of a fixing roller during runaway. Provided is a fixing device in which a phenomenon of ignition is less likely to occur even when the fixing roller remains in contact with the fixing device, and which further has a large heat retaining effect on the surface of the fixing roller. A fixing device includes a fixing roller, a pressure roller provided to face the fixing roller,
A temperature control means for detecting the temperature of the fixing roller 1 and controlling the temperature of the fixing roller 1 was provided. An electric heating sheet 7 was interposed between the core 4 of the fixing roller 1 and the surface coating layer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device.

[0002]

2. Description of the Related Art A typical conventional fixing device is disclosed in (1) Japanese Patent Application Laid-Open No. 3-44682, which will be described with reference to FIG. .
It includes a fixing roller 21 having a non-contact type fixing heater 22 installed therein, a pressure roller 23 provided opposite to the fixing roller 21, a temperature sensor 24 for detecting the temperature of the fixing roller 21, A temperature control means 25 is provided which receives a temperature from the temperature sensor 24, controls the temperature of the fixing roller 21 by comparing the temperature with a set temperature.

Next, as another type of fixing device,
(2) There is one disclosed in Japanese Patent Application Laid-Open No. Hei 4-326387, which will be described with reference to FIG. It is a heating element 32 that generates heat by power supply on the surface of the fixing roller 31.
A temperature detector for detecting the temperature of the heating element 32
33, a temperature controller 34 for controlling the temperature of the heating element 32 from the temperature detected by the temperature detector 33 and the set temperature.
Is provided.

[0004]

In the fixing device as described in the above (1), a fixing roller is provided for each operation state.
Since the temperature of 21 is changed and used by the temperature control means 25, if the amount of change in the set temperature is large, the apparatus may start until the set mode reaches the set temperature. Therefore, there is a problem that wasteful standby time and power consumption are required, and the fixing efficiency is poor. In the fixing device as described in (2), the problem of the fixing device as in (1) can be solved. However, since the heating element 32 is provided on the surface of the fixing roller 31, runaway occurs. When a sheet or the like is kept in contact with the surface of the fixing roller 31 at a time, there occurs a problem that a fire occurs relatively quickly, and the effect of keeping the surface of the fixing roller 31 warm is small.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional fixing device, and reduce the standby time and power consumption until the set mode reaches the set temperature, thereby improving the fixing efficiency. An object of the present invention is to provide a fixing device which is excellent, does not easily cause a phenomenon of ignition even when paper or the like is kept in contact with the surface of the fixing roller during runaway, and has a large effect of keeping the surface of the fixing roller warm.

[0006]

According to the present invention, there is provided a fixing apparatus for achieving the above object.
The present invention provides a fixing device including a fixing roller, a pressure roller provided opposite to the fixing roller, and a temperature control unit that detects a temperature of the fixing roller and controls a temperature of the fixing roller. An electric heating sheet is interposed between the core of the fixing roller and a surface coating layer. The invention according to claim 2 is the invention according to claim 1, wherein an electric current is constantly supplied to the electric heating sheet. The temperature of the fixing roller is kept constant by the temperature control means.

According to a third aspect of the present invention, when the temperature of the fixing roller reaches the set temperature, the supply of current to the electric heating sheet is temporarily stopped, and the temperature of the fixing roller is reduced. When the temperature becomes lower than the set temperature, an electric current is supplied to the electric heating sheet, and the invention according to claim 4 is such that in the invention according to claim 3,
When the temperature of the fixing roller becomes 1% or more higher than the set temperature, the supply of current to the electric heating sheet is temporarily stopped, and when the temperature of the fixing roller becomes 1% or more lower than the set temperature, current is supplied to the electric heating sheet. It is characterized by the following.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIGS. 1 to 3, an electric heating sheet 7 is interposed between a core 4 of a fixing roller 1 and a surface coating layer 6. FIG.

In such a device, a current is constantly supplied to the electric heating sheet 7 so that the temperature of the fixing roller 1 is detected by the temperature sensor 3.
When it is detected that the temperature set by the temperature control means (not shown) has been reached, the supply of current to the electric heating sheet 7 is temporarily stopped, and when the temperature of the fixing roller 1 becomes lower than the set temperature, the electric heating sheet is A current is supplied to the fixing roller 7 to keep the temperature of the fixing roller 1 constant.

At this time, in order to keep the temperature of the fixing roller 1 constant, the upper and lower limits of the temperature of the fixing roller 1 are set to 1% of the set temperature, and when the detected temperature becomes higher than the set temperature by 1% or more, the electric heating sheet The supply of current to the heating sheet 7 is temporarily stopped, and when the temperature becomes lower than the set temperature by 1% or more, the current is supplied to the electric heating sheet 7.

[0011]

As described above, the present invention is as described above. In the fixing device according to the first aspect of the present invention, an electric heating sheet is interposed between the core of the fixing roller and the surface coating layer.
The waiting time and power consumption until the set mode reaches the set temperature are reduced, and the fixing efficiency is good, and even if paper or the like remains in contact with the surface of the fixing roller during runaway, fire occurs Is less likely to occur, and the effect of keeping the surface of the fixing roller warm is great.

According to a second aspect of the present invention, in the first aspect of the invention, a current is constantly supplied to the electric heating sheet, and the temperature of the fixing roller is kept constant by the temperature control means. There is an effect that the descent of can be prevented.

According to a third aspect of the present invention, in the first aspect of the invention, when the temperature of the fixing roller reaches a set temperature, the supply of current to the electric heating sheet is temporarily stopped, and the temperature of the fixing roller is reduced. When the temperature is lower than the set temperature, an electric current is supplied to the electric heating sheet, so that there is an effect that power consumption can be reduced.

According to a fourth aspect of the present invention, in the third aspect of the invention, when the temperature of the fixing roller becomes higher than the set temperature by 1% or more, the supply of the current to the electric heating sheet is temporarily stopped. When the temperature of the fixing roller becomes lower than the set temperature by 1% or more, a current is supplied to the electric heating sheet, so that the surface temperature of the fixing roller is maintained in an optimum and stable state, and the inrush current generated by turning off / on causes There is an effect that a voltage drop can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of the same.

FIG. 3 is a vertical sectional front view of the same.

FIG. 4 is a perspective view of a conventional fixing device of the same type as the present invention.

FIG. 5 is a perspective view of a fixing roller of another conventional fixing device of the same type as the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Temperature sensor 4 Core 6 Surface coating layer 7 Electric heating sheet

Claims (4)

[Claims] 1. A fixing device comprising: a fixing roller; a pressure roller provided to face the fixing roller; and a temperature control means for detecting the temperature of the fixing roller and controlling the temperature of the fixing roller. A fixing device, wherein an electric heating sheet is interposed between a core of the fixing roller and a surface coating layer. 2. The fixing device according to claim 1, wherein a current is constantly supplied to the electric heating sheet, and the temperature of the fixing roller is kept constant by a temperature control unit. 3. When the temperature of the fixing roller reaches a set temperature, the current supply to the electric heating sheet is temporarily stopped, and when the temperature of the fixing roller becomes lower than the set temperature, the current is supplied to the electric heating sheet. The fixing device according to claim 1, wherein: 4. The fixing roller according to claim 1, wherein the temperature of the fixing roller is lower than the set temperature by one.
4. The method according to claim 3, wherein the supply of the current to the electric heating sheet is temporarily stopped when the temperature rises by more than 1%, and the current is supplied to the electric heating sheet when the temperature of the fixing roller becomes lower than the set temperature by 1% or more. Fixing device.