JPH0637950A - Heat generation control system - Google Patents

Abstract

PURPOSE:To improve the utilization efficiency of a copying machine used with a heater, etc., by evading a system down due to the short of the switch for ON/OFF control of a heater as a heat generating body. CONSTITUTION:This heat generation control system monitors the temperature fluctuation of the heater being the heat generating body and performs the ON/ OFF control of the heater. The system is provided with first and second switching parts 5 and 6 for turning ON/OFF first and second power supply lines 2 and 3 of a power supply for the heater and a temperature control part 10 for performing the normal heat generation control of the heater by turning ON/OFF the first power supply line 2 by using the first switching part 5 based on the monitored result of the normal temperature fluctuation of the heater and for performing the heat generation control of the heater at a normal temperature fluctuation value by turning ON/OFF the second power supply line 3 by using the second switching part 6 when the normal temperature is exceeded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on / off control technique for a heating element such as a heater used in a printing mechanism such as a facsimile machine or a copying machine, and particularly, it efficiently performs on / off control of the heating element when an abnormality occurs. The present invention relates to a heat generation control system suitable for

[0002]

2. Description of the Related Art In a device having a printing function such as a facsimile or a copying machine, a heater is used for printing. In such a printing operation, the temperature of the heater melts the toner or the like adhering to the paper corresponding to the image information, and the temperature control of the heater is important for high-quality printing. .

Conventionally, the temperature control of the heater is performed by monitoring the temperature change (ambient temperature) of the heater, for example, by utilizing the resistance change of the thermistor, and turning the heater on and off so as to reach a predetermined temperature. There is. For example, when the temperature of the heater reaches 190 ° C., the heater is turned off by turning off the switch on the power supply line to the heater. After turning off the heater, the temperature rises to, for example, 198 ° C. and then starts to drop. Then, when the temperature monitored by the thermistor again reaches 190 ° C., the switch is turned on to heat the heater to raise the temperature. This operation is repeated to keep the temperature of heat generated by the heater constant.

Even if the temperature exceeds 190 ° C. due to a defective switch, heater, or thermistor,
If the power supply to the heater is continued, a serious trouble such as ignition will occur. In order to avoid such trouble, the conventional heater heat generation control system is provided with a thermostat, a thermal fuse, and the like provided on the power supply line to the heater. That is, when the heat generation temperature of the heater reaches 235 ° C., for example, the power supply to the heater is forcibly stopped by the thermostat or the temperature fuse. As a conventional technique relating to such heater temperature control, there is, for example, the one described in Japanese Patent Laid-Open No. 63-296082.

However, if the power supply to the heater is forcibly stopped immediately by the thermostat or the temperature fuse when the heater has an abnormal temperature rise, the heater abnormal temperature rise due to a short circuit of the switch. Even at times, the operator cannot use the facsimile machine or the copying machine using the heat generation control system of the heater until an engineer who can solve this trouble comes, which causes a hindrance to the work. Further, if the thermostat or the thermal fuse fails together with the switch, it becomes impossible to avoid a large trouble such as ignition.

[0006]

The problem to be solved by the present invention is that in the prior art, the on / off control of the power supply line to the heating element such as the heater by the switch is performed only on one power supply line side. This is a point that cannot efficiently cope with the abnormal temperature rise trouble of the heating element due to a failure of a single body or the abnormal temperature rise trouble of the heating element due to a composite failure of the switch, the thermostat, the temperature fuse and the like. An object of the present invention is to solve the problems of these conventional techniques, avoid immediate stop of power supply to the heating element due to a failure of a switch for ON / OFF control of the heating element, and when a trouble around the heating element occurs. It is an object of the present invention to provide a heat generation control system capable of improving the utilization efficiency of a facsimile, a copying machine, or the like.

[0007]

In order to achieve the above object, the heat generation control system of the present invention performs (1) on / off control of the heat generating element based on the result of monitoring the temperature change of the heat generating element such as a heater. A heat generation control system for maintaining a temperature of a heating element at a predetermined temperature change value, which includes a first switch section for turning on / off a first power supply line side of the heating element and a first switching section for turning on / off a second power supply line side of the heating element. 2 switch parts,
Based on the monitoring result of the predetermined temperature change value of the heating element, the first switch section is used to turn on / off the first power supply line side to perform the normal on / off control of the heating element to monitor the temperature of the heating element. When the result exceeds a predetermined temperature change value, the second switch section is used to provide a temperature control section for turning off the second power supply line side. (2) In the heat generation control system according to (1), the temperature control unit uses the second switch unit when the monitoring result of the temperature of the heating element exceeds a predetermined temperature change value. It is characterized by comprising an abnormal temperature control unit for turning on and off the second line side and performing normal on / off control of the heating element based on a result of monitoring a predetermined temperature change value of the heating element. Also,
(3) In the heat generation control system according to any one of (1) and (2) above, the temperature control unit is configured to, when the temperature monitoring result of the heat generating element exceeds a predetermined temperature change value, generate the heat generating element. Of the abnormal high temperature monitoring result of No. 2 to the operator, and by the operator's instruction input based on the notification of this abnormality notification unit, the off control state and the on / off control of the second power line side by the second switch A mode switching unit for switching between the state and the state is provided.

[0008]

In the present invention, a first switch section and a second switch section for turning on and off the heating element are provided on the first power source line side and the second power source line side of the heating element respectively, and during normal operation. , The second switch is always turned on, and the first switch is turned on / off to control the heat generation of the heating element with a predetermined temperature change value. If the first switch is short-circuited and the temperature of the heating element rises abnormally, turn off the second switch before turning to the temperature at which forced power shutdown by a thermal fuse or thermostat is reached. The power supply to the heating element is stopped on the side of the second power supply line to lower the temperature of the heating element. After that, the second switch is turned on / off to control the heat generating operation of the heat generating element at the normal temperature. Further, at this time, the operator is notified by a buzzer or blinking display, and the operator is made to select whether the heating element is completely turned off or on / off control is performed. By doing so, it is possible to avoid the immediate stop of the power supply to the heating element due to the failure of the switch for the on / off control of the heating element.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the configuration of the heat generation control system of the present invention according to the present invention. In this figure, 1 is a 100 V AC power supply, 2 and 3 are a first power supply line and a second power supply line respectively connected to the AC power supply 1.
The power supply line 4 includes an AC / DC converter that generates a DC power supply from the AC power supply 1 for a DC drive unit (not shown), and 5 includes a triac relay or the like.
Is provided on the power supply line 2 of the
A first switch (indicated as SW1 in the figure) for turning on / off on the side of the power supply line 2 is provided on the second power line 3 and a second switch for turning on / off on the side of the second power line 3
Switch (denoted as SW2 in the figure), 7 is an AC power supply 1
As a heating element for generating heat by
The thermistor 9 for measuring the heat generation temperature of is provided on the first power supply line 2 and disconnects the first power supply line 2 when the heat generation temperature by the heater 7 reaches a predetermined temperature, for example, 235 ° C. The temperature fuse 10 for stopping the heat generation of the heater 7 controls ON / OFF of the first switch 5 and the second switch 6 based on the temperature measurement result of the thermistor 8 to set the heat generation temperature of the heater 7 to a predetermined value. The temperature control unit 11 for controlling, particularly, the abnormal temperature control unit 12 for performing on / off control of the second switch 6 when the first switch 5 is short-circuited has a buzzer, a lamp, etc., and the heater 7 The abnormality notification unit 13 for notifying the operator that the on / off control of No. 1 is transferred to the control using the second switch 6,
Based on the notification from the abnormality notification unit 12, the operator inputs an instruction input unit for inputting heat generation control for the heater 7 to either off control or on / off control. Based on the operator's instructions
It is a mode switching unit that switches the heat generation control of the heater 7 by the second switch 6 to OFF control or ON / OFF control.

In this embodiment, the second switch 6
Is normally on by the temperature control unit 10. Then, the temperature control unit 10 turns on and off the first switch 5 based on the temperature change of the heater 7 to control the heat generation of the heater 7. That is, the temperature control unit 10 monitors the temperature change of the heater 7 using the resistance change of the thermistor 8, and when the temperature rises to a predetermined value, for example, 190 ° C., the first switch 5 is turned off. The heater 7
Stop fever. In this way, when the heater 7 is turned off, the temperature rises to some extent and then falls. In this way, when the temperature drops and the temperature monitored by the thermistor 8 reaches 190 ° C. again, the first switch 5 is turned on and the heater 7 is caused to generate heat. By repeating this operation, the heat generation temperature of the heater 7 is maintained at around 190 ° C.

Here, when the power supply to the heater 7 is continued even if the temperature exceeds 190 ° C. due to a short circuit failure of the first switch 5, the heating temperature is 23 in the prior art.
The temperature fuse 9 melts at 5 ° C and is forced to
The power supply to the heater 7 is stopped. However, in the heat generation control system of the present embodiment, the temperature control unit 10 turns off the second switch 6 when the temperature monitored by the thermistor 8 reaches, for example, 200 ° C. to turn off the heater 7. Stop the power supply. After that, the abnormal temperature controller 11 turns on and off the second switch 6 at 190 ° C. based on the temperature monitoring of the thermistor 8,
The heat generation of the heater 7 is controlled.

At this time, the temperature control unit 10 has the abnormality notification unit 1
By outputting an alarm buzzer sound or an alarm display via 2, the operator is notified that an abnormal state has occurred, and a technician is contacted. Further, based on the instruction input from the instruction input unit 13 by the operator who confirms this notification, the temperature control unit 10 causes the mode switching unit 14 to control the heater 7 using the second switch 6 by the abnormal temperature control 11. Switching is performed between a state in which the heat generation control is continued and a state in which the second switch 6 is turned off and the heater 7 is kept off.

By doing so, the on / off control of the heater 7 can be continued by the switch 6 of FIG. 1 until an engineer who can deal with the failure comes, and the operator can
You can continue to work using a facsimile or copier. Further, in consideration of safety, for example, when only the print output at the time of reception by the facsimile is stopped, the operator can give an instruction using the instruction input unit 13. That is, based on this instruction, only the second switch 6 is turned off so that the operation of, for example, the AC / DC converter 4 can be continued and the facsimile transmission operation can be made possible.

FIG. 2 is an explanatory view showing an embodiment of a change in heater temperature controlled by the heat generation control system in FIG. In this figure, Tt is 190 ° C. and Te is 200.
C. and Tb are temperatures of 235 ° C., and the heat generation control system in FIG.
On / off control of the heater is performed based on the outputs at e and Tb. That is, as shown by the line A in the figure, normally T
The heater temperature is controlled by using the first switch 5 of FIG. 1 based on t, but when the temperature reaches Te as shown by the line B in the figure, when the temperature of the heater reaches Te, On / off of the heater 7 is controlled by the Tt temperature on the side of the second power supply line 3 by using the switch 2 of 2. At this time, the operator is notified of the abnormality by sounding an alarm or lighting an abnormality display lamp.

If the temperature rise of the heater cannot be controlled even by controlling the second switch 6 of FIG. 1, the temperature fuse 9 of FIG. 1 is melted after reaching Tb (time C in the figure). , The first power supply line 2 side in FIG. 1 is opened, and the power supply to the heater 7 is stopped.

FIG. 3 is a flow chart showing an embodiment of the processing operation according to the present invention of the heat generation control system in FIG. This figure shows the processing operation by the temperature control unit 10 in FIG. 1. First, the temperature detection output T from the thermistor is read (step 301). It is determined whether or not the output T indicates an abnormal temperature rise (T> Te) (step 302). If T <Te and the temperature is normal, the normal heater control operation using the first switch 5 in FIG. 1 is continued (step 303). T> Te
If the temperature is abnormal, the alarm process for the operator is performed (step 304), and the normal heater control operation (normal temperature control though it is an abnormal situation) using the second switch 6 in FIG. 1 is continued. Yes (step 305).
During the heater control operation, if the temperature of the heater rises to an abnormal value, for example, 235 ° C.,
The thermal fuse 9 shown in FIG. 1 is melted, and the power supply to the heater is stopped.

As described above with reference to FIGS. 1 to 3, in the heat generation control system of this embodiment, a switch for turning the heater on and off is provided in each of the two power supply lines, and one switch is short-circuited. , The other switch turns on / off another power line side. As a result, it is possible to avoid a system down of a facsimile, a copying machine or the like due to a short-circuit of a switch for heater on / off control. The present invention is not limited to the embodiment described with reference to FIGS. For example, a thermostat may be used instead of the thermal fuse. Further, in the present embodiment, the heater for the AC power source has been described, but the present invention can be similarly applied to the heater for DC, or other heating element instead of the heater.

[0018]

According to the present invention, it is not necessary to stop the power supply to the heating element due to the failure of the switch for controlling the ON / OFF of the heating element such as the heater, and the facsimile or It is possible to improve the utilization efficiency of a copying machine or the like.

[0019]

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a configuration relating to the present invention of a heat generation control system of the present invention.

FIG. 2 is an explanatory diagram showing an example of a change in heater temperature controlled by the heat generation control system in FIG.

FIG. 3 is a flowchart showing an embodiment of a processing operation according to the present invention of the heat generation control system in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 1st power supply line 3 2nd power supply line 4 AC / DC converter 5 1st switch 6 2nd switch 7 Heater 8 Thermistor 9 Temperature fuse 10 Temperature control part 11 Abnormal temperature control part 12 Abnormality notification Part 13 Instruction input part 14 Mode switching part

Claims (3)

[Claims] 1. A heat generation control system for performing on / off control of the heat generation element based on a result of monitoring a temperature change of a heat generation element such as a heater to keep the temperature of the heat generation element at a predetermined temperature change value. The first switch means for turning on / off the first power supply line side, the second switch means for turning on / off the second power supply line side of the heating element, and the monitoring result of the predetermined temperature change value of the heating element. Based on the above, by using the first switch means, the first power supply line side is turned on / off to perform normal on / off control of the heating element, and the result of monitoring the temperature of the heating element is the predetermined temperature change value. And a temperature control means for turning off the second power supply line side by using the second switch means. 2. The heat generation control system according to claim 1, wherein the temperature control means causes the second switch means to operate when the monitoring result of the temperature of the heating element exceeds the predetermined temperature change value. The second power supply line side is turned on and off, and an abnormal temperature control means is provided for performing normal on / off control of the heating element based on a result of monitoring a predetermined temperature change value of the heating element. And a heat generation control system. 3. The heat generation control system according to claim 1 or 2, wherein the temperature control means determines that the temperature monitoring result of the heating element exceeds the predetermined temperature change value. , An abnormality notifying means for notifying an operator of an abnormal high temperature monitoring result of the heating element, and an operator's instruction input based on the notification of the abnormality notifying means, whereby the second power line side by the second switch A heat generation control system comprising: a mode switching means for switching between an off control state and an on / off control state.