JPH09319250A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of reducing the number of flickering times caused in another electric equipment by reducing the remarkable number of voltage variation times of a power source at low cost. SOLUTION: This fixing device 1 is provided with a fixing means 2 having heating means 4 and 5, temperature detecting means 6 and 7 detecting the temperature of the fixing means 2, and a control means 8 controlling the heat generation of the heating means 4 and 5 corresponding to temperature detection output detected by the detecting means 6 and 7. The device 1 is provided with a time measuring means outputting the detection output of the detecting means 6 and 7 at every given time. Then, the temperature detection output outputted at every given time is inputted in the control means, which turns on or off the heating means 4 and 5 corresponding to the temperature detection output.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a fixing device for an image forming apparatus.

[0002]

2. Description of the Related Art Most of the conventional fixing devices have the same structure as that of the first embodiment of the present invention, and will be described with reference to FIG. That is, the fixing device 1 has a central heating means 4 having a central heater for heating the central portion of the fixing means 2, and
A roller-shaped fixing unit 2 having an end heating unit 5 having end heaters for heating both ends, a roller-shaped pressure unit 3 in pressure contact with the fixing unit 2, and a central portion of the fixing unit 2. The central temperature detecting means 6 for detecting the temperature, the end temperature detecting means 7 for detecting the end temperatures, and the temperature detection outputs of these temperature detecting means 6, 7 are inputted, and the central and end heating means 4, 4. And a control means 8 for controlling the energization of the fixing means 5, and the fixing means 2 is heated by the central and end heating means 4, 5.
The recording paper on which the toner image has been transferred is passed through the nip portion between the fixing means 2 and the pressing means 3, and the toner image on the recording paper is fixed by pressure and heating, and the center and end temperature detecting means 6, In accordance with the temperature of the fixing means 2 detected by 7, the central and end heating means 4 and 5 are frequently turned on or off so that the fixing means 2 maintains a predetermined set temperature. .

A fixing device 1 of this type is known as disclosed in Japanese Patent Application Laid-Open No. 62-8183.
This is because when the control means 8 starts to turn on the exposure light source of the exposure means during the image forming operation, the end heating means 5 is used when the temperature of the fixing means 2 reaches a predetermined set value, and the central heating means is used when the temperature of the fixing means 2 is not reached. 4 is forcibly turned on during the lighting period of the exposure light source, and the central heating unit 4 and the end heating unit 5 are turned on when the fixing unit 2 does not reach the set temperature during the non-lighting period of the exposure light source. is there.

[0004]

In the conventional fixing device as described above, the central heating means and the end heating means are frequently turned on or off in response to the temperature detection signal of the temperature detection means, and turned on. At times, a sudden inrush current occurs, and when the light is turned off, the power supply is released, the power supply voltage fluctuates remarkably, which may cause malfunctions in other electrical equipment. Therefore, there is a problem that the adverse effect is great such that the operator is made uncomfortable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional fixing device, reduce the number of voltage fluctuations of the power source remarkably at low cost, and reduce the number of flicker generated in other electric equipment. It is to provide a fixing device capable of performing.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 is such that in the fixing device as described above, the detection output of the temperature detecting means is output at predetermined time intervals. A time measuring means is provided, and the temperature detecting output output at each predetermined time is input to the control means, and the control means
The heating means is turned on or off according to the temperature detection output.

According to a second aspect of the present invention, in the first aspect of the invention, a predetermined time interval for the timing means to output the temperature detection output to the temperature detection means is at the time of image formation when the recording paper passes through the fixing means. Is different from the start-up time and the non-image forming time in the standby mode.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Most of the embodiment of the present invention shown in FIG. 1 is the same as the above-mentioned conventional one, and therefore the same parts are designated by the same reference numerals and the description thereof will be omitted.
Mainly different parts will be described. It is composed of a central heating means 4 having a heater in the central part and a end heating means 5 having heaters at both ends, which are built in a roller-shaped fixing means 2, via triacs 11 and 12, respectively, and further a relay (RA1). It is connected to the AC 100V power source 16 via 15. Triacs 11 and 12 are control drivers 1 respectively
It is connected through 3 and 14 to the control means 8 having the CPU 10, and the central and end heating means 5 and 6 are turned on (on) and turned off (off) based on a command signal from the control means 8. Therefore, when the triacs 11 and 12 are turned on while the relay 15 is on, electric power is supplied to the central and end heating means 5 and 6, respectively.

Further, the fixing means 2 detected by the central temperature detecting means 6 having a thermistor provided in contact with the outer peripheral surfaces of the center and the end of the fixing means 2 and the end temperature detecting means 7 having the thermistor. The surface temperatures of the central portion and the end portions of the control means 8 are input to the control means 8, and the CPU 10 of the control means 8
The analog signals from the center and end temperature detecting means 6 and 7 are converted into digital signals and used as temperature data of the fixing means 2.

A timer means 9 having a timer is provided, and the timer means 9 measures the temperatures of the central portion and the end portion of the fixing means 2 detected by the central and end portion temperature detecting means 6 and 7 at predetermined time intervals. Then, the control means 8 turns on or off the central heating means 4 and the end heating means 5 in accordance with the output temperature.

When the main body cover of the image forming apparatus is opened at the time of an abnormality such as a paper jam, the control means 8 receives a signal from the cover switch 17 for detecting the opening.
The relay 15 is opened so that the central and end heating means 4 and 5 are not energized.

In such a structure, the central heating means 4
The operation flow of turning on and off the end heating means 5 and the end heating means 5 is as shown in FIGS. 2 and 3, but the operation flow of the central heating means 4 and the end heating means 5 is the same, and FIGS. Since the same applies to the above, the operation of the central heating means 4 shown in FIG. 2 will be described.

In the operation flow of the central heating means 4, the predetermined time interval of the time measuring means 9 is set to 1 second, and after the central heating means 4 is turned on or off in advance during the image forming operation, After 1 second has elapsed (step 2-3: Yes), the time measuring means 9 outputs the temperature of the central portion of the fixing means 2 detected by the central temperature detecting means 6 to the control means 8. At that time, the clocking means 9 is restarted so that the central heating means 4 is turned on or off again after one second (step 2-5). Then, the control unit 8 determines that the temperature of the central portion of the fixing unit 2 is equal to or lower than the target temperature M-5 ° C (step 2-6: Yes) and the central heating unit 4 is off (step 2-7: No). ), It is turned on (step 2-9), the temperature of the central portion of the fixing means 2 is equal to or higher than the target temperature M (step 2-11: Yes), and the central heating means 4 is turned on. In case of (step 2-13: No), it is turned off (step 2-15).

That is, after 1 second has elapsed from the preceding turning on or off of the central heating means 4 corresponding to the detected temperature of the central portion of the fixing means 2, the following turning off or on is not executed. . That is, the central heating means 4 is not turned on or off for at least 1 second.

Further, the time counting means 9 is always added, and is cleared at the step of "timer restart (step 2-4)" shown in the flow chart.

Furthermore, in order to reduce flicker, it is not necessary to add a countermeasure component such as a transformer or a filter circuit (LCR circuit), and the product is increased in size and weight due to an increase in space for mounting the countermeasure component. Increase, cost U
There is no P.

The first embodiment may be applied to heat generation control of the fixing means 2 having one heating means instead of having the two heating means as described above.

The second embodiment is different from the first embodiment in that
The predetermined time interval at which the time measuring means 9 outputs the temperature data of the central portion and the end portion of the fixing means 2 detected by the central and end portion temperature detecting means 6 and 7 is set at the time of image formation when the recording paper passes through the fixing means. In addition, the difference is set between the start-up and the standby non-image formation. That is, the predetermined time interval, which was 1 second in the first embodiment, is changed to 5 seconds when image formation is not performed during standby and during image formation standby (during preheating).

In such a case, when the timer value of the time measuring means 9 has passed 5 seconds, the center of the fixing means 2 detected by the central temperature detecting means 6 and the end temperature detecting means 7 again after 5 seconds. There is no difference from the first embodiment except that the clocking means 9 is reset and restarted so as to output respective temperatures of the portion and the end portion. The operation flow is as shown in steps 2-17 to 2-29 of FIG. 2 and steps 3-17 to 3-30 of FIG. 3, respectively.

In such an arrangement, the central heating means 4
And the operation flow with the end heating means 5 is the same,
The operation flow of the central heating means 4 will be described. As shown in FIG. 2, the central heating means 4 is turned on or off when image formation is not performed, and when the image forming apparatus is abnormal such as when the main body cover is opened or when a paper jam occurs. Except for when the power is on (step 2-2: No) and the predetermined time interval does not elapse 5 seconds again (step 2-17: Yes), the central portion and the end portion of the fixing unit 2 are separated. The detected temperature is not output. Therefore, the central heating means 4 is not energized from on to off or from off to on for at least 5 seconds. That is, after 5 seconds have passed, the control unit 8 determines that the temperature of the central portion of the fixing unit 2 is equal to or lower than the target temperature M-5 ° C (step 2-20: Yes) and the central heating unit 4 is off (step 2-21). : No), the central heating means 4 is turned on (step 2-23), and the fixing means 2
If the temperature of the central part of the is equal to or higher than the target temperature M (step 2-25: Yes) and the central heating means 4 is on (step 2-27: No), it is turned off (step 2).
-29), such control is repeated after 5 seconds. The end heating means 5 is also similar to the above as shown in steps 3-17 to 3-29 in FIG.

Although the time interval for controlling the ON / OFF of the heater is different between the image forming operation and the non-image forming operation, they may be performed at the same time interval.

[0022]

The present invention is as described above. According to the first aspect of the present invention, there is provided a fixing device as described above.
A time measuring means for outputting the detection output of the temperature detecting means at every predetermined time is provided, and the temperature detecting output outputted at the predetermined time is inputted to the control means, and the control means heats corresponding to the temperature detection output. Since the means is turned on or off, there is an effect that it is possible to reduce the number of times of significant voltage fluctuation of the power supply at a low cost and reduce the number of flicker occurring in other electric devices.

According to a second aspect of the present invention, in the first aspect of the invention, the predetermined time interval at which the time measuring means outputs the temperature detection output to the temperature detecting means is at the time of image formation when the recording paper passes through the fixing means. Since it is different between the start-up and the non-image formation at the time of standby, there is an effect that it is possible to reduce the number of times the voltage fluctuation of the power supply is remarkable and to further reduce the number of flicker occurring in other electric devices at low cost. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is an operation flow chart of turning on or off the central heating means of the first and second embodiments of the present invention.

FIG. 3 is an operation flow chart of turning on or off the end heating means.

[Explanation of symbols]

 1 Fixing Device 2 Fixing Means 4 Central Heating Means 5 Edge Heating Means 6 Central Temperature Detecting Means 7 Edge Temperature Detecting Means 8 Control Means 9 Clocking Means

Claims (2)

[Claims] 1. A fixing means having a heating means for heating and fixing a toner image on a recording sheet, a temperature detecting means for detecting a temperature of the fixing means, and a heating means corresponding to a temperature detection output detected by the temperature detecting means. In the fixing device having control means for controlling the heat generation of the temperature detecting means, a time measuring means for outputting the detection output of the temperature detecting means at every predetermined time is provided, and the temperature detecting output outputted at the predetermined time is inputted to the control means. Then, the fixing device turns on or off the heating device in response to the temperature detection output. 2. The predetermined time interval at which the time measuring means outputs the temperature detection output to the temperature detecting means is different between the time of image formation when the recording paper passes through the fixing means and the time of non-image formation during start-up and standby. The fixing device according to claim 1, wherein: