JP3486319B2 - Fixing heater control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a fax machine,
The present invention relates to a fixing heater control device such as a printer.

[0002]

2. Description of the Related Art As a fixing heater of this type, a large amount of electric power is required.
This halogen heater is often used, and in such a conventional heater, a lighting device (such as a fluorescent lamp) connected to the same power supply line due to a voltage drop caused by a large rush current flowing during lighting. There have been problems such as flicker, a so-called flicker phenomenon, and reset in an electronic circuit using a CPU.

As countermeasures against these, for example, the actual Kaihei 1-50
There is one disclosed in Japanese Patent No. 633, which is as shown in FIG. 4, in which heaters are divided and each heater 1 and a controller 3 such as a triac or SCR are connected in series, The signal distributor 7 connected to the controller 3 and the setting means disperse the current that sequentially flows for each current waveform to prevent flicker due to the inrush current.

[0004]

In the method of dividing the heater and distributing the electric power and lighting as described above, since the heater is controlled with a small electric power, the number of times of lighting is rather increased, and the halogen heater is turned on. Since the life of the lamp is determined by the number of times it is lit, complicated lighting cannot be performed, and it takes time to detect after lighting if it is determined from the temperature rise rate detected by a thermistor, so it is necessary to deal with flicker. However, there is a problem in the detection performance, such as when the temperature rise rate is low during copying or when the heater is turned on. Also, since the required fixing wattage differs depending on the copy status (transfer paper size, copy interval, etc.), if the heater is turned on and off uniformly (when there are multiple heaters), control with a wattage higher than necessary Therefore, there is also a problem that the temperature overshoot becomes large, power is wasted wastefully, and the life of the fixing roller is shortened.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional heater control device, to average the number of times each heater is turned on, to extend the life of the heater, reduce power consumption, and generate flicker. It is an object of the present invention to provide a fixing heater control device capable of preventing the above.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of fixing heaters, and stores the number of times each fixing heater is turned on. , By comparison, the order in which the fixing heater is turned on
A controlling unit for performing ordinal pickled, wherein, when the heater turn-on, a <br/> fixing heater control unit, wherein the to Turkey the number of lighting times in average.

According to a second aspect of the present invention , a plurality of fixing rollers are provided.
Is provided to control the number of times each fixing heater is turned on.
When the fixing heater is turned on, it has a means for storing the lighting time.
The fixing heaters are controlled to be averaged, and the fixing heaters are turned on in order from the fixing heater that has been turned on the most, and when the lights are turned off , the fixing heaters are turned off in the reverse order. If, fixing heater control unit der to and controls to light the off the fixing heater again
It

The invention according to claim 3 is the same as claim 1 or
In the invention described in 2 , all fixing heaters are turned on.
And means for detecting an AND signal output when all of the fixing heater even though the non-illuminated
Instead , when the detection means detects an AND signal, the fixing heater is turned off, the copying operation is stopped, and an abnormality is displayed on the display device.

[0009]

1 is a block diagram of an embodiment of the present invention. In this embodiment, reference numeral 1 denotes a fixing heater control device, which includes a control circuit 2, a lighting circuit 3, and a fixing unit 4. The control circuit 2 has a CPU 5 and an AND gate 7. The CPU 5 has an input terminal connected to the thermistor 8 and the AND gate 7, and an output terminal connected to the AND gate 7 and the display device 9. The AND gate 7 has its input terminal connected to the CPU 5 and its output terminal connected to the input terminal of the CPU 5. The SSR 6 of the lighting circuit 3 has an input terminal connected to the input terminal of the AND gate 7, one output terminal connected to the fixing heater 10, and the other output terminal connected to the power supply circuit.
Connected to 11. The fixing heater 10 of the fixing unit is built in the fixing roller 12 and has one terminal connected to the SSR 6 and the other terminal connected to the power supply circuit 11.

The CPU 5 built in the control circuit 2 reads the temperature information from the thermistor 8 arranged in the vicinity of the fixing roller 12, and when it detects that the surface temperature of the fixing roller 12 has dropped below a predetermined temperature, the heater 5 The lighting signal of is output. All the lighting signals are also connected to the AND gate 7, and when all outputs are turned on, a signal indicating all lighting is output to the CPU 5. Further, the CPU 5 has a means for storing the number of times of lighting and a means for comparing.

The AND gate 7 outputs an output signal to the CPU 5 only when the all lighting signal output from the CPU 5 is input.

The lighting signal output from the CPU 5 is output to the heater lighting control element of the fixing heater lighting circuit 3. An SSR (solid-state relay) 6 with a built-in zero cross is used as a heater lighting control element, and current is supplied from the zero cross point of alternating current during lighting, so that the rush current is reduced.
Three fixing heaters 10 are connected, and a lighting circuit is connected to each of them. The wattage of each of these heaters is a value obtained by dividing the wattage required for fixing into three equal parts.

The operation will be described with reference to the flow chart of FIG. 2. During normal standby, the temperature of the heater gradually drops, or the temperature drops because heat is rapidly taken away by the transfer paper at the start of copying. When the surface temperature of the fixing roller 12 falls below the specified temperature (step 1), C
Since the PU 5 stores the number of times of lighting, the current number of times of lighting of the fixing heater 10 is compared and the PU 5 is ordered from the one having the largest number of times of lighting (step 2). In this case, if the number of times of lighting is large in the order of A, B, and C, the CPU 5 first lights A (step 3), and again detects the temperature after a fixed time (step 4). At this time, if the temperature is still below the specified temperature, B is turned on next (step 5), and if the temperature is still below the specified temperature after a certain period of time (step 6), C
Lights up (step 7). When all the lights are turned on, a signal for reconfirmation is output from the AND gate 7 to the CPU 5, and C
PU5 can detect all lighting.

In the time chart of FIG. 3, a, b, and c are lighting signals from the CPU 5 to each heater, and FIG. 3 shows a case where the heater is operating normally. Since the CPU 5 stores the state of the output signal, all the lighting signals, a,
When b and c are output, the CPU 5 detects the signal of d from the AND gate 7 and reconfirms that all the lights are on, and at other times (when one of the heaters A, B and C is off). Time)
When the signal d is detected, the CPU 5 determines that it is a malfunction signal, stops the copying operation, and displays SC (serviceman call) on the display device 9 of the operation unit.

When the lamp is turned off, it is not turned off at a time, but the wattage is reduced in order, thereby functioning to minimize the voltage fluctuation at the time of turning off. In addition, since the required fixing wattage varies depending on the copy state (transfer paper size, copy interval, etc.) at that time (A: always on, B: keep the specified temperature range by turning on / off, or A, B: always on,
By performing control such as C: maintaining a specified temperature range by turning on / off, it is possible to perform stable control with small temperature fluctuations (temperature overshoot becomes large when controlling with a wattage higher than necessary). Become.

[0016]

The present invention is as described above. According to the invention described in claim 1, since the number of times of lighting of a plurality of heaters becomes uniform, the life of a specific heater is not shortened, and it is relatively possible. This has the effect of extending the life of the fixing device.

The invention according to claim 2 has an effect that stable control with less temperature fluctuation is possible.

According to the third aspect of the present invention, it is possible to prevent the occurrence of flicker and to stop the machine by instantaneously detecting an unexpected full lighting signal, thereby preventing the occurrence of other problems. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flow chart diagram showing an operating state of the present invention.

FIG. 3 is a time chart diagram of the present invention.

FIG. 4 is a circuit diagram of a conventional heater control device of the same type as the present invention.

[Explanation of symbols]

1 Fixing heater controller 5 CPU 7 AND gate 9 Display device 10 Fixing heater

Claims (3)

(57) [Claims] 1. A plurality of fixing heaters are provided, and the number of times each fixing heater is turned on is stored and compared to determine the fixed number.
It has a control means for ordering the lighting of the heater
Serial control means when the heater on, fixing heater control unit, wherein the benzalkonium be <br/> the number of lighting times in average. 2. A plurality of fixing heaters are provided, each of which is provided with a fixing heater.
It has a means to store the number of times the fixing heater is turned on.
When the heater is turned on, it is controlled to average the number of times it is turned on.
And, and, fixing heater went illuminated from the lighting Most Viewed fixing heater in the order, but unlit is turned off in the reverse order, when deviated from a specified temperature within after off a predetermined time, the off the fixing heater again it <br/> and controls so as to turn on the Fixing heater controller. 3. Output when all the fixing heaters are turned on.
And means for detecting an AND signal power, all the constant
Despite wearing heater is not lit, the sensing hand
3. The fixing heater control device according to claim 1, wherein when the stage detects an AND signal, the fixing heater is turned off, the copying operation is stopped, and an abnormality is displayed on the display device.