JPH1091036A - Temperature controller for heating/fixing unit for printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature controller for a heating/fixing unit for a printer which can be used in common for different commercial power sources, can light a lamp without using waveform control and does not generate higher harmonic of power source, flicker noises, etc. SOLUTION: This temperature controller for the heating/fixing unit for a printer to which a two-system input voltage consisting of a first voltage and a second voltage double the first voltage is selectively supplied is provided with three lamps 4a-4c disposed in a heating roller constituting the heating/fixing unit, a supply voltage identification circuit 12 for identifying the input voltage to output a voltage identification signal D and a CPU 1A for driving three lamps 4a-4c in response to the voltage identification signal. Then, the CPU 1A turns on, in series, three lamps 4a-4c, when the voltage identification signal shows the first voltage and turns on three lamps 4a-4c one by one in each cycle of the input voltage, when the voltage identification signal shows the second voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling the output temperature of a halogen lamp in a heat roller (heat fixing unit) of an electrophotographic printer, and more particularly to a method for controlling an input voltage supplied to the halogen lamp. The present invention relates to a temperature control device for a heating and fixing device for a printer, which maintains a stable output temperature, enables common use of a halogen lamp, and prevents generation of noise and the like.

[0002]

2. Description of the Related Art Generally, in a copying machine or an electrophotographic printer, a heat source such as a halogen lamp (hereinafter simply referred to as a lamp) having a rated power of about 1 kW is used to fix a toner image transferred onto a recording sheet. Is used. Therefore, this type of printer device is provided with a temperature control device for maintaining the output temperature of the heat fixing device (heating source) at a predetermined value.

FIG. 5 shows a conventional heat fixing device for a printer (hereinafter, referred to as JP-A-2-166490).
FIG. 3 is a circuit block diagram illustrating a control device of a fixing device, which illustrates a case where temperature control is performed using a single heater (lamp). FIG. 6 is a timing chart showing the operation of the conventional device of FIG.

In FIG. 5, reference numeral 1 denotes a CPU for performing arithmetic processing for temperature control, 2 denotes a gate circuit for passing a control pulse C from the CPU 1, and 3 denotes a triac which is driven on and off by the control pulse C via the gate circuit 2. Reference numeral 4 denotes a lamp (halogen lamp) connected in series to the triac 3 to constitute a heating source for fixing, and reference numeral 5 denotes an AC power supply for supplying power to the lamp 4 via the triac 3. Lamp 4
It is arranged in a heat roller that is pressed against printer paper (not shown).

[0005] Reference numeral 7 denotes a transformer for stepping down a commercial power supply voltage to a predetermined voltage, 8 a zero-cross detection circuit for detecting a zero cross of the step-down voltage from the transformer 7, and 9 a voltage detection circuit for detecting a step-down voltage from the transformer 7. is there. The output signals of the detection circuits 8 and 9, that is, the zero cross pulse Z and the power supply voltage V are input to the CPU 1.

Reference numeral 10 denotes a phase control circuit for controlling the phase of the control pulse C. Reference numerals 15 to 17 denote counters, memories and timer circuits connected to the CPU 1, respectively, and L and M from the electrophotographic printer (not shown) to the CPU 1. These are the input lamp lighting signal and the temperature detection signal.

Next, the operation of the conventional fixing device temperature controller shown in FIG. 5 will be described with reference to the timing chart of FIG. When the temperature is controlled by a single heater as shown in FIG. 5, the CPU 1 responds to the input voltage via the transformer 7 with the zero cross pulse Z from the zero cross detection circuit 8.
And the voltage detection circuit 9 detects the power supply voltage V.

As a result, as shown in FIG.
The control pulse C is output to the phase control circuit 10 after the lapse of the control time T from the timing of the zero cross pulse Z. At this time, the amount of heat output from the lamp 4 is controlled by changing the output timing (control time T) of the control pulse C.

When a lamp lighting signal L is input from the printer body, the CPU 1 sends a control pulse C to the phase control circuit 10.
Output to Thus, the gate circuit 2 turns on the triac 3 to turn on the lamp 4 from the output timing of the control pulse C to the output timing of the zero cross pulse Z. Further, the CPU 1 changes the lighting time of the lamp 4 while monitoring the temperature detection signal M fed back from the fixing device, and controls the fixing device to a predetermined temperature.

As described above, the CPU 1 controls the timing (control time T) of the control pulse C in synchronization with the power supply voltage V and adjusts the lighting waveform of the lamp 4 so that the CPU 1 Also output the same supply power W, thereby realizing the common use of the lamp 4.

[0011] However, as shown in FIG.
Becomes a distorted waveform and a harmonic current is generated, so that the harmonic current flows into the power supply circuit including the AC power supply 5 and may cause a failure in other electric devices.

In view of the above, there has been proposed an apparatus for controlling a supply power to be constant by switching a plurality of heaters. FIG. 7 is a configuration diagram showing a main part of another example of a conventional temperature control device for a fixing device described in Japanese Patent Application Laid-Open No. Hei 7-121055, in which two heaters are switched and used as a heating source 4A. Shows the case.

In FIG. 7, 4A is a heating source corresponding to the lamp 4, and 3 and 5 are the same as those described above.
11a and 11b are two filaments or heaters arranged in parallel. The heaters 11a and 11b are provided in the same heating source 4A for the purpose of miniaturization.

Next, the operation of the conventional temperature control device for a fixing unit shown in FIG. 7 will be described. In this case, for example,
Two heaters 11a having a rated voltage of 100 V and a heater 11b having a rated voltage of 200 V are prepared, and an input voltage (100 V or 20 V) is provided.
0V), an appropriate one of the heaters 11a and 11b is selectively used (see an arrow in FIG. 7). This makes it possible to make the supplied power substantially constant, as described above.

[0015]

As described above, in the conventional temperature control device for a fixing device, when a single heater (lamp 4) is used as shown in FIG. 6) becomes a distorted waveform, and a harmonic current is generated, which impairs other electric devices. Therefore, there is a problem that regulation of the harmonic current is required.

If the power supply time is controlled on a cycle basis without using the phase control circuit 10, the current waveform becomes a sine wave, but the interval of the on / off time is widened. However, there is a problem that flicker noise is generated for the illumination light source.

Further, as shown in FIG. 7, two heaters 11a are provided.
And 11b, two heaters (filaments) 11a having greatly different rated voltages are used.
And 11b need to be sealed in the same heating source 4A, so that it is difficult to select a sealing gas and it is expensive, and there is a problem that the fixing device becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in consideration of a different commercial power supply (for example, 1
It is an object of the present invention to provide a temperature control device for a heating and fixing unit for a printer that can be shared with two systems (00 V and 200 V) and that does not generate power supply harmonics or flicker noise. Another object of the present invention is to provide a temperature control device for a heating and fixing device for a printer, which realizes miniaturization.

[0019]

According to a first aspect of the present invention, there is provided a temperature control apparatus for a heat fixing device for a printer, comprising two systems consisting of a first voltage and a second voltage twice as large as the first voltage. In a temperature control device for a heat fixing device for a printer to which one of the input voltages is selectively supplied, three lamps provided in a heat roller constituting the heat fixing device;
And a supply voltage identification circuit that identifies one of the second voltage and the second voltage and outputs a voltage identification signal; and a CPU that drives the three lamps in response to the voltage identification signal. When the first voltage is indicated, the three lamps are turned on in parallel, and when the voltage identification signal indicates the second voltage, three lamps are sequentially turned on for each cycle of the input voltage. It lights up one by one.

According to a second aspect of the present invention, there is provided a temperature control device for a heat fixing device for a printer according to the first aspect.
Each of the lamps has a length in the axial direction set to 1/3 of the width of the printer paper and is arranged in series in a heat roller.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a circuit block diagram showing Embodiment 1 of the present invention, wherein 1A corresponds to a CPU 1,
L, M and 5 are the same as described above. Also, 2a
2c correspond to the gate circuit 2, 3a to 3c correspond to the triac 3, 4a to 4c correspond to the lamp 4, and they are respectively arranged in parallel. Further, G1 to G
3 is a gate signal of three systems corresponding to the control pulse C.

Reference numeral 12 denotes a supply voltage discriminating circuit connected between both ends of the AC power supply 5, which has a power supply voltage of 100V to 120V.
And a range of 200 V to 240 V, and outputs a voltage identification signal D corresponding to the power supply voltage. in this case,
Three juxtaposed lamps 4a to 4c constituting a heating source for fixing
Are each constituted by a halogen lamp having a rated voltage of 120V.

Next, the operation of the first embodiment of the present invention shown in FIG. 1 will be described with reference to FIGS. 2 and 3 are timing charts showing a control operation according to the first embodiment of the present invention. FIG. 2 shows a case where the power supply voltage is 100 V, and FIG. 3 shows a case where the power supply voltage is 200 V.

First, the difference in power consumption according to the input voltage of the commercial power supply will be described. 2. Description of the Related Art In general, a commercial power supply used as an operating power supply for an electric device or the like is increasingly supplied with a single-phase three-wire power distribution system. Therefore,
In the range of 100V to 120V, or twice that of 200V to 24V
Any supply voltage in the range of 0V is selectively used.

The voltage characteristic between the input voltage V1 and the power consumption W1 of a halogen lamp, which is a kind of incandescent lamp, is expressed by the following equation (1): rated power W0 and rated voltage V0.
It is known to be represented by an exponential function characteristic using

W1 / W0 = (V1 / V0) ^1.52 (1)

In equation (1), for example, the rated voltage 1
When an input voltage of 240 V is applied to a halogen lamp of 20 V, the power consumption W1 with respect to the rated power W0 is V0 =
By substituting 120 [V] and V1 = 240 [V], they are expressed as in the following equation (2).

W1 / W0 = (240/120) ^1.52 = 2.87 (2)

As is apparent from equation (2), the input voltage V
1 is 240V, 120V (W1 / W0 =
It can be seen that the power consumption is about three times that of 1). Therefore, when the input voltage is 240 V, it is proved that almost the same power can be obtained by setting the gate signals G1 to G3 to a use duty of 1/3 of the case of 120V.

In view of the above facts, in the present invention, as shown in FIG.
a to 4c are used to form a fixing heating source, which is connected to three gate circuits 2a to 2c and three triacs 3a to 3a.
3c.

That is, the power consumption W1 is proportional to the input voltage V1 to the approximately 1.5 power (see equation (1)), and if the input voltage V1 is doubled, the power consumption W1 is about three times (equation (2)). CPU 1A turns on all the lamps 4a to 4c in parallel when the input voltage V1 is 100V (first voltage), and when the input voltage V1 is 200V (second voltage), Each of the lamps 4a to 4c is turned on one by one in each cycle of the input voltage V1. Thus, the power consumption in the fixing device can be made substantially the same regardless of the input voltage.

Hereinafter, the switching drive control operation of each of the lamps 4a to 4c according to the first embodiment of the present invention will be specifically described. First, the CPU 1A executes the supply voltage identification circuit 1
2 to determine whether the power supply voltage is 100 V system (see FIG. 2) or 200 V system (see FIG. 3), and according to the identification result, the lamps 4a to 4c are as follows.
Drive.

That is, when a power supply voltage of 100 V is input as shown in FIG. 2, when the lamp lighting signal L is input, the gate signals G1 to G3 are simultaneously switched, and the triac 3a is switched via the gate circuits 2a to 2c. To 3c are turned on, and the three lamps 4a to 4c are simultaneously turned on.

When a 200V power supply voltage is input as shown in FIG. 3, when the lamp lighting signal L is input, the gate signals G1 to G1 are output every cycle of the input voltage.
G3 is sequentially switched, and the three lamps 4a to 4c are turned on one by one in time series.

As a result, the duty used for each of the gate signals G1 to G3 is reduced to 1/3 of that in the case of the 100 V system, so that the power consumption Wa to Wc of each of the lamps 4a to 4c is 10
It is almost equal to the case of 0V system.

Further, the input current i is determined by each of the lamps 4a to 4c.
Corresponding to the composite waveform of the power consumption Wa to Wc.
In both the 0V system (FIG. 2) and the 200V system (FIG. 3), a continuous sine waveform is obtained.

As described above, by switching the drive control of the lamps 4a to 4c in accordance with the voltage of the AC power supply 5, it is possible to drive the lamps 4a to 4c with the same power regardless of the difference in the commercial power supply. 100V system and 200V
Can be shared with the system.

Further, the triacs 3a to 3c are turned on and off by the gate signals G1 to G3, which are rectangular pulses synchronized with the input voltage waveform of the AC power supply 5, without using the waveform control, as shown in FIGS. 2 and 3. In addition, the input current i has a continuous sinusoidal waveform, and it is possible to prevent generation of harmonic currents, generation of flicker noise due to fluctuations in power supply voltage, and the like.

Embodiment 2 In the first embodiment, the size and arrangement of each of the lamps 4a to 4c are not particularly mentioned. However, each of the lamps 4a to 4c is configured to be 1/3 of the required size and arranged in series to reduce the size. It may be realized.

FIG. 4 is a structural view showing a main part of a second embodiment of the present invention in which respective lamps 4a to 4c are arranged in series. In FIG. 4, 2, 3, 4a to 4c and 5 are the same as those described above. Things. Reference numeral 6 denotes a heat roller of the fixing device, and three lamps 4a to 4c are arranged in series along the axial direction inside the fixing device. P is printer paper thermocompression-bonded by the heat roller 6, and A is the transport direction of the printer paper P.

In this case, the axial length of each of the lamps 4a to 4c is set to 1/3 of the width of the printer paper P required for fixing. This makes it possible to reduce the length of the heat roller 6 constituting the voltage-shared fixing device to a size equivalent to the case where one lamp is used. The lighting control operation for each lamp 4 is the same as described above, and will not be described here.

[0042]

As described above, according to the first aspect of the present invention, two system input voltages consisting of the first voltage and the second voltage which is twice the first voltage are selectively supplied. In a temperature control device for a heat fixing device for a printer, a voltage discrimination signal is output by discriminating three lamps provided in a heat roller constituting the heat fixing device and one of a first voltage and a second voltage. And a CPU that drives the three lamps in response to the voltage identification signal.
When the voltage identification signal indicates the first voltage, the three lamps are turned on in parallel. When the voltage identification signal indicates the second voltage, three lamps are turned on every cycle of the input voltage. Since the lamps are sequentially turned on one by one, they can be shared by different commercial power supplies, and a temperature control device for a heat fixing device for a printer that does not generate power supply harmonics or flicker noise can be obtained. There is.

According to a second aspect of the present invention, in the first aspect, the length of the three lamps in the axial direction is set to 1/3 of the width of the printer paper, and the three lamps are used. Since they are arranged in series in the heat roller, there is an effect that a temperature control device for a heat fixing device for a printer, which is downsized, can be obtained.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing Embodiment 1 of the present invention.

FIG. 2 is a timing chart showing a control operation in a 100 V system according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing a control operation in a 200 V system according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing a main part of a second embodiment of the present invention.

FIG. 5 is a circuit block diagram showing an example of a conventional temperature control device for a heat fixing device for a printer.

FIG. 6 is a timing chart showing the operation of a conventional temperature control device for a heat fixing device for a printer.

FIG. 7 is a configuration diagram showing a main part of another example of a conventional temperature control device for a heat fixing device for a printer.

[Explanation of symbols]

1A CPU, 2, 2a-2c Gate circuit, 3, 3a
3c triac, 4a-4c lamp, 5 AC power supply, 6 heat roller, 12 supply voltage identification circuit, D
Voltage identification signal, G1 to G3 gate signal, P Printer paper.

Claims (2)

[Claims] 1. A temperature control device for a heating and fixing device for a printer to which one of two input voltages consisting of a first voltage and a second voltage twice as large as the first voltage is selectively supplied. In the above, three lamps arranged in a heat roller constituting a heat fixing device, a supply voltage identification circuit that identifies one of the first and second voltages and outputs a voltage identification signal, A CPU that drives the three lamps in response to a voltage identification signal; wherein the CPU turns on the three lamps in parallel when the voltage identification signal indicates the first voltage. If the voltage identification signal indicates the second voltage, the three lamps are sequentially turned on for each cycle of the input voltage.
A temperature control device for a heat fixing unit for a printer, which is turned on one by one. 2. The three lamps according to claim 1, wherein the length of each of the three lamps in the axial direction is set to one third of the width of the printer paper, and the three lamps are arranged in series in the heat roller. Item 2. A temperature control device for a heat fixing device for a printer according to Item 1.