JPH02254481A - Fixing temperature controlling method - Google Patents

Abstract

PURPOSE:To make temperature distribution of a fixing roller even by controlling a multiple number of heaters to be turned on and off so that the temperature of the necessary paper range according to the paper size is made even. CONSTITUTION:Because the temperature at both edges of the fixing roller 2 is low during the standby period, the heaters 1-1 and 1-3 are turned on by a temperature controlling controller 4 responding to output of temperature detecting devices 3-1 and 3-2. Further, in the case of continuous passing of paper, since the temperature at the both edge parts of the fixing roller 2 is high and low in the central part, the heaters 1-1 and 1-3 are controlled to be turned off and a heater 1-2 is turned on by a comparator 5 of the controller 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to fixing temperature control of a thermal fixing device using an electrophotographic process.

(Prior Art) In copying machines, printers, facsimile machines, and the like that utilize an electrophotographic process, there is a heat fixing method as a method of fixing an image on paper. In this heat fixing method, it is necessary to continuously supply heat within an appropriate range in order to fix the paper and toner.

FIG. 3 shows a cross section (one part) of a conventional fixing section and a temperature control controller. In Figure 3, 3
1 is a heater, 32 is a fixing roller, 33 is a temperature detection device,
34 is a temperature control controller 6 The heater 31 is built into the fixing roller 32, and the heat generated by the heater 31 is transmitted to the surface of the fixing roller 32 through the fixing roller 32. This heat is detected by a temperature detection device 33 disposed at the center of the surface of the fixing roller 32 and controlled by a temperature control controller 34. Already
The output of the temperature detection device 33 is compared with the reference temperature level set in the temperature control controller by a comparator 35. If the temperature is low, the heater 31 is turned on, and if the temperature is high, the heater 31 is turned off.
FF.

In such an apparatus, the surface temperature of the fixing roller 32 is as shown in FIG. In FIG. 4, the shaded area is the appropriate temperature range for fixing the paper and toner. When the device is stopped, the temperature distribution is as shown by curve 36, but when the paper passes through it (continuously) becomes the temperature distribution of curve 37.

(Problem to be Solved by the Invention) However, in the above conventional method, - one heater and one
Since the temperature is controlled by individual temperature detection devices, the temperature distribution changes greatly between before paper passing and during continuous paper feeding. That is, there is a problem in that the temperature at both ends of the fixing roller is low before paper passes, and the temperature at both ends of the fixing roller becomes high when paper is continuously passed.

The present invention solves the above-mentioned conventional problems.

It is an object of the present invention to provide a fixing temperature control method that makes the temperature distribution uniform over the entire area of the fixing roller.

(Means for Solving the Problems) In order to achieve the above object, the present invention is provided with a function of dividing the heater part into a plurality of parts and turning them ON/OFF independently, and a temperature detection device of the same number as the number of divisions of the heater. Alternatively, the temperature can be controlled by using a heater divided into multiple parts and one temperature detection device, so that the required paper range of n11 degrees can be kept constant depending on the paper size. 0N
-OFF is controlled.

(Function) Therefore, according to the present invention, the temperature distribution of the fixing roller in the required paper range becomes uniform, so that the fixability of the toner to the paper is improved.

(Embodiment) FIG. 1 shows a cross section of a fixing section and a temperature control controller in an embodiment of the present invention. In Figure 1,
Reference numeral 1 denotes a heater, and the heater 1 includes three heating elements, heaters 1-1.1-2.1-3.

2 is a fixing roller, 3 is a temperature detection device, and heater 1
Three pieces 3-1 to 3-3 are arranged corresponding to -1 to 1-3. 4 is a temperature control controller, 5 is a comparator, and there are 3 sets (corresponding to the temperature detection device 3 and heater 1).
5-1 to 5-3).

Next, the operation of the above embodiment will be explained. First, during the waiting period, the song becomes like $36 in FIG.
-1 and heater 1-3 are turned on.

This allows the temperature at both ends of the fixing roller 2 to be increased. In addition, in the case of continuous paper feeding, the temperature at both ends of the fixing roller 2 is high and the temperature at the center is low, contrary to when it is on standby.
The comparator 5 of the temperature control controller 4 controls the heater 1-
1 and heaters 1-3 are OFF.

The heater 1-2 is controlled to be turned on. By dividing the heater into a plurality of parts and providing corresponding temperature detection devices in this way, it becomes possible to keep the fixing temperature constant by turning each heater on and off independently.

FIG. 2 shows a cross section of a fixing section and a temperature control controller according to another embodiment of the present invention. 1 to 5 in Figure 2
The numbers are the same as the corresponding numbers in FIG. In the embodiment shown in FIG. 2, one temperature detection device 3 is arranged in the center.
Each heater 1-
Using control patterns 1 to 1-3, the reference temperature of the temperature controller 4 is varied and the surface temperature of the fixing roller 2 is controlled to be within an appropriate range. For example, if the paper size is narrow and continuous paper feeding is required, heater 1-1 and heater 1-3 are turned off.
The temperature at both ends of the fixing roller 2 is controlled so as not to be too high. During the standby period, the temperature at both ends of the fixing roller 2 is low, so the heater 1-1.1-2 is turned on and controlled so as not to become too low.

Even if there is only one temperature sensing device as mentioned above.

By dividing the heaters and controlling them individually, the temperature on the surface of the fixing roller can be controlled to be constant, and an appropriate temperature for thermal fixing can be ensured.

(Effects of the Invention) As is clear from the above embodiments, the present invention has first-order effects.

(1) It becomes possible to uniformly control the temperature distribution over the entire area of the fixing roller, improving the uniformity of paper and toner production.

(2) Only one temperature detection device is required, and the temperature distribution of the fixing roller can be controlled uniformly, thereby reducing costs.

(3) Since there is no need to raise the temperature excessively, energy saving and safety can be achieved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross section of a fixing section and a temperature control controller in one embodiment of the present invention, FIG. 2 is a diagram showing a cross section of a fixing section and a temperature control controller in another embodiment of the present invention, and FIG. 4 is a diagram showing a cross section of a conventional fixing unit and a temperature control controller, and FIG. 4 is a diagram showing surface temperature characteristics of a fixing roller in the conventional example. 1.31...Heater, 2,32...Fixing roller, 3,33...Temperature detection device, 4.34...Temperature control controller, 5,35...Comparator. Diagram Temperature detection device

Claims (1)

[Claims] In a heat fixing device using an electrophotographic process, the heater part is divided into multiple parts and each heating element is turned on individually.
Equipped with a temperature control means that can be turned off and a plurality of temperature detection means corresponding to the division of the heater or one temperature detection means in the paper path,
When there are a plurality of temperature detection means, the outputs of the plurality of temperature detection means are sent to the temperature control means, and when there is only one temperature detection means, the outputs of the temperature detection means and usage status (paper size, standby/continuous use) information are sent to the temperature control means. A fixing temperature control method characterized by controlling the temperature of a heat fixing section to a constant value by inputting the following information.