JPH09197892A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce influence for other equipments connected to the same power source by controlling rapid voltage fluctuation caused by a rush current at the time of starting energizing a heater. SOLUTION: The heater 14c of a fixing device 14 is energized while controlling a solid state relay 53 triggering the gate of a TRIAC 62 by a transistor 57 on/off-controlled from a control part 31 detecting the surface temperature of the heater 14 during a normal fixing operation. Also, at the time of starting energizing the heater 14c, the driving of the TRIAC 62 is controlled by the main control part 31 switching the transistor 57 based on an input power source voltage value. Input power source voltage in this case is detected by a power source voltage detecting circuit part 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to a fixing device for thermally fixing an image formed on a recording medium.

[0002]

2. Description of the Related Art In a conventional fixing device, a heater provided on a fixing roller as a fixing member is a halogen heater or a ceramic heater having a large heat capacity. Therefore, when the toner image is thermally fixed on the transfer paper as the recording medium, the voltage applied to the heater also becomes high. Also,
As a power source for the image forming apparatus, there is a power source using a universal power source which can be used in both 100V and 200V regions. Further, in the fixing device, when the temperature of the fixing roller is lower than the set temperature, the heater is energized, and when the temperature is higher than the set temperature, the energization is stopped to keep the fixing roller at a predetermined temperature. There is provided heater control means.

[0003]

However, when the power consumption of the heater is the same, the input voltage is 100V and 200V.
Since the current value is different from that of the V system, when the heater is simply turned on and off for heater control, the rush current of the heater at the start of energization becomes large. Moreover, the input voltage is 200
In the case of the V system, the inrush current flowing at the start of energization when the heater is turned on becomes large when the input voltage is 100 V, compared to the inrush current when the current is started when the heater is turned on. There is a problem that the flicker of lighting equipment and the like connected to the same power source increases due to the voltage drop due to.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to suppress abrupt voltage fluctuation due to an inrush current at the start of energization of a heater so that another heater connected to the same power source can be used. An object of the present invention is to provide a fixing device capable of reducing the influence on the device.

[0005]

In order to achieve the above object, a fixing device according to a first aspect of the present invention is a heat fixing means for heat fixing unfixed toner on a recording medium, and the heat fixing means. A heater driving means for driving the heater of the heat fixing means, and the heater based on the input power supply voltage of the power supply device when energization of the heater is started. And a fixing device control means for controlling the driving of the heater driving means so that the surface temperature of the thermal fixing means becomes a predetermined temperature during the normal energizing operation. Characterize.

According to a second aspect of the present invention, the input power supply voltage of the power supply device is detected by the power supply voltage detecting means.

According to a third aspect of the present invention, the power supply voltage detecting means outputs a voltage having a waveform similar to a half wave of an AC waveform of the power supply device.

According to a fourth aspect of the present invention, the input power supply voltage of the power supply device is discriminated in the main control section by an input voltage discriminating means connected to the main control section.

According to a fifth aspect of the invention, the fixing device control means includes the main control section and a switching element which is on / off controlled by the main control section.

According to a sixth aspect of the present invention, the heater driving means is constituted by connecting a solid state relay to the gate of the triac.

According to a seventh aspect of the present invention, the heater driving means is driven by the phase control of the fixing device control means.

According to the invention of claim 8, the heater driving means is driven by the wave number control of the fixing device control means.

[Operation] Based on the above configuration, during the normal fixing operation, the heater of the heat fixing means is energized while the heater driving means is controlled by the fixing device control means. Further, at the start of energization of the heater, the driving of the heater driving means by the fixing device control means is controlled based on the input power supply voltage. In this case, the input power supply voltage is detected by the power supply voltage detection means.

The input power supply voltage may be discriminated by the main control section by the input voltage discriminating means.
Then, the driving of the heater driving unit by the fixing unit control unit at the start of energization is controlled based on the determined input power supply voltage. By these controls, the inrush current to the heat fixing unit is suppressed.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. <First Embodiment> FIG. 1 is an overall schematic configuration diagram showing an image forming apparatus according to the present invention, FIG. 2 is a control block diagram showing a printer control device, and FIG. 3 is a first embodiment. FIG. 4 is a control circuit diagram of the surface temperature of the heater of the fixing device according to FIG. 4, FIG. 4 is an operation explanatory diagram showing a driving signal of the heater, and FIG.

In FIG. 1, an image forming apparatus main body (apparatus main body) is provided with an upper cassette 1 for accommodating recording paper SH as a recording medium and a recording paper SH having a size different from that of the recording paper SH accommodated in the upper cassette 1. A lower cassette 2 for accommodating is mounted. Paper feed rollers 3 and 4 are respectively provided in the apparatus main body which is located above the tip side (the left side in the drawing) of the upper cassette 1 and the lower cassette 2 in the apparatus main body. These paper feed rollers 3 and 4 are cassettes 1 and 2.
The recording sheets SH contained in the sheet are separated and taken out one by one, and are fed to the registration roller pair 5. The registration roller pair 5 conveys the recording paper SH fed from the paper feed rollers 3, 4 or the paper refeed roller 19 to the image recording unit at a predetermined timing.

The image recording section is provided around the photosensitive drum 11.
The primary charger 6, the developing device 7, and the developing device 7 are sequentially arranged along the rotation direction.
A transfer charger 8, a cleaner 9 and a charge eliminating lamp 10 are arranged. Of these, the primary charger 6 uniformly charges the photosensitive drum 11 (drum type electrophotographic photosensitive member). The developing device 7 is for jumping developing the electrostatic latent image formed on the photosensitive drum 11 with, for example, one-component toner. The transfer charger 8 transfers the developed toner image onto the recording paper SH.
The cleaner 9 collects the toner remaining on the photosensitive drum 11. The charge eliminating lamp 10 exposes the photosensitive drum 11 to neutralize the residual charge.

The laser unit 12 is a polygon mirror 1 which rotates at a constant speed by a scanner motor 13a.
3 is irradiated with laser light, and an electrostatic latent image corresponding to image information is formed on the photosensitive drum 11 via the folding mirror 13b. The fixing device 14 as a heat fixing device fixes the toner image by applying heat and pressure to the recording paper SH after the transfer process. The fixing device 14 serves as a fixing member having a heater 14c provided therein. The fixing roller 14a, the pressure roller 14b, and the thermistor 14d, which is a temperature detecting element for detecting the surface temperature of the fixing roller 14a, are used.

The flapper 15 switches between discharging the recording paper SH for which the fixing process is completed to the stacking tray 23 or the re-feeding tray 43, and the discharging roller 1
When the recording sheet SH is discharged to the refeed tray 43 side via 6, the recording sheet SH is conveyed to the reversing roller 17 side by the flapper 15. When the recording mode is single-sided, the reversing roller 17 rotates in the forward direction to eject the recording paper SH for which the fixing process has been completed. When the recording mode is double-sided, the reversing roller 17 rotates in the forward direction, and after the trailing edge of the recording paper SH for which the fixing process has finished passes the reversing sensor 21, the reversing direction is immediately reversed and the reversing roller 17 is again rotated. The recording paper SH is pulled into the main body of the apparatus. The recording sheet SH drawn into the apparatus main body is relayed and transported to the position where the sheet refeed roller 19 is disposed via the relay roller 18. It should be noted that the upper cassette 1, the lower cassette 2, the sheet feeding rollers 3, 4 and the like constitute a first feeding unit, and the reversing roller 17, the relay roller 18, the sheet re-feeding roller 19 and the like constitute a second feeding unit. Composed.

The printer control device 24 in the figure is connected via an interface 26 to a host computer 25 which is an external device. The printer control device 2
Reference numeral 4 is for receiving the image information and controlling the driving of the laser unit 12 and the like, and also for collectively controlling the driving of each driver necessary for the image forming sequence.

The printer controller 24 will be described in detail below with reference to FIG.

The main motor 27 drives the photosensitive drum 11, the paper feed rollers 3 and 4, the reversing roller 17, the relay roller 18, the paper refeed roller 19, and the like. Driven. The beam detector 28 receives the laser light emitted from the laser unit 12 immediately before writing the image and outputs a beam detectry signal. The beam detection circuit section 36 shapes the beam detecto signal output from the beam detector 28. To generate a horizontal sync signal. Solenoid clutch 29
Is a paper feed roller 3, 4, a reversing roller 17, a relay roller 1
8. It turns on / off the driving of the re-feeding roller 19 and the like, and is driven by the solenoid clutch drive circuit section 37. The sensor group 30 including the paper path sensors 20, 22 (see FIG. 1) and the reversing sensor 21 outputs the sensor output to the main control unit 31 as a control unit via the sensor input circuit unit 38. The main control unit 31 has a ROM 3
It is a one-chip microcomputer (MPU) including 1a, a RAM 31b, a comparator 31c, and the like.

The image processing circuit section 32 has a format and timing in which the image information and the print control command from the host computer 25 are written in the sequence of the printer and the main control section 31.
To be sent. Polygon motor drive circuit unit 34
Is for driving the polygon mirror 13 at a constant rotation speed. The laser drive circuit section 35 modulates and emits laser light in accordance with image information input from the host computer 25. The lamp drive circuit section 39 turns on or off the static elimination lamp 10. The high-voltage control circuit unit 40 applies a predetermined high voltage to the primary charger 6, the developing unit 7, and the transfer charger 8, and the fixing unit control circuit unit 41 includes the surface temperature of the fixing roller 14 a of the fixing unit 14. Is controlled to a predetermined temperature.

Next, the fixing device control circuit section 41 and the power supply voltage detection circuit section as the power supply voltage detection means will be described.

In FIG. 3, the fixing device control circuit section 41 is
It is as shown below. That is, the heater 14c in the fixing device 14 is connected to a commercial power supply (AC power supply) 51 which is a power supply device via a triac 53a in a solid state relay (SSR) 53 described later.
The SSR 53 includes a triac 53a, an LED 53b, a zero-cross detection circuit (not shown), and the like.
The anode of D53b is DC power supply Vcc through the resistor 60.
And the cathode is connected to the collector of an NPN transistor (switching element) 57 having a grounded emitter. The base of the transistor 57 is connected to the output port of the main controller 31. The fixing device control unit is composed of the main control unit 31 and the transistor 57, and the heater driving unit is composed of the SSR 53 and the triac 62. Then, when the LED 53b emits light, the triac 53a becomes conductive and triggers the other triac 62 to heat the heater 14c. Therefore, when the main control unit 31 sets the output port to L (OFF), the LED 53b does not light up, so the heater 14
When c does not generate heat and the output port is set to H (ON), the LED 53b lights up and the heater 14c generates heat. In addition, reference numerals 63 and 64 in the figure are resistors respectively.

The power supply voltage detection circuit section 50 is as follows. That is, the rectifier 75 has the commercial power supply 51 connected to its input side and the LED 71b of the phototransistor 71 connected to the output side via the resistor 70. The phototransistor 71 is a transistor 71
a, an LED 71b, and a zero-cross detection circuit (not shown). Then, when the LED 71b emits light, the transistor 71a becomes conductive, and a voltage having a waveform similar to the half-wave of the AC waveform of the commercial power supply 51 is applied to the capacitor 73 through the resistor 72 and discharged by the resistor 74.
This voltage is smoothed by the capacitor 73, becomes an analog voltage Vi, and is input to the A / D conversion port of the main control unit 31. Therefore, since the analog voltage Vi is proportional to the input power supply voltage (commercial voltage), the main control unit 31 detects the input power supply voltage.

On the other hand, the thermistor 14d in the fixing device 14
Has one end connected to the DC power supply Vcc and the other end grounded through the resistor 55. Thermistor 1
The analog voltage determined by the value of the resistor 55 is input to the A / D conversion input port of the main control unit 31 in 4d, and the main control unit 3
1 detects the temperature of the fixing device 14.

Next, the image recording operation will be described with reference to FIGS.

First, the host computer 25 instructs the printer control device 24 to feed paper from the paper feed rollers 3 and 4 or feed paper from the paper refeed roller 19, and to the destination of the recording paper SH. Is specified to instruct to start recording.

Here, when the host computer 25 always designates the destination as the stacking tray 23, the one-sided recording is performed, and the sheet feeding is designated by the upper cassette 1 or the lower cassette 2.
When the sheet feeding from the sheet and the sheet re-feeding roller 19 are designated alternately and the destination is designated between the sheet re-feeding tray 43 and the stacking tray 23, double-sided recording is performed.

In this case, when the printer control device 24 receives a recording start command from the host computer 25, the fixing roller 14 is operated based on the feeding of the recording paper SH and the designation of the destination.
The surface temperature of a is set individually.

The control of this embodiment will be described below with reference to the flowchart shown in FIG.

First, when the commercial power supply 51 is turned on (step S1), the main controller 31 determines whether the input power supply voltage is 100V system or 200V system (step S2). And
When the input power supply voltage is determined to be 200V system, the heater 14
c is turned on as shown in FIG. 4A (step S3),
The heater is controlled by a normal on / off control (step S4), and the surface temperature of the fixing roller 14a of the fixing device 14 is controlled to a predetermined temperature. Further, when the input power supply voltage is determined to be 100V system, the heater 14c is turned on at the start of energization as shown in FIG.
As shown in (1) (step S5), phase control is performed to suppress the inrush current (step S6). Then, after the inrush current applied to the heater 14c becomes stable, the heater control is shifted to the normal on / off control (step S4).

In this way, when the main controller 31 determines that the input power supply voltage is the 200V system, the normal ON / OFF heater drive signal as shown in FIG. 4A is output.
On the other hand, when it is determined that the input power supply voltage is 100V system,
At the start of energization as shown in FIG. 4B, a heater drive signal for performing a control to gradually delay the phase angle by the phase control is output. That is, when it is determined that the system is the 200V system, the normal on / off signal is output from the main control unit 31. On the other hand, if it is determined that the system is 100V, the inrush current can be suppressed by performing the phase control that gradually lengthens the ON time of the heater 14c at the start of energization.

In the present embodiment, the control at the start of energization of the 100V system heater 14c is performed by the phase control, but the energization method of the heater 14c may be performed by another control method such as wave number control. It is valid. <Second Embodiment> Next, a second embodiment will be described.

The configuration of the second embodiment is almost the same as the configuration of the first embodiment, except that the main control section 31 does not judge the input power supply voltage but the power supply voltage specification. When a unit such as a heater or a heat fixing device of different type is installed in the main body of the apparatus, is it a 100V system or a 200V system?
It is provided with an input voltage discriminating means capable of discriminating whether or not it is a V system, and changes control based on the voltage detected by the input voltage discriminating means.

FIG. 6 is a circuit diagram showing a power supply voltage detection circuit section and a fixing device control circuit section according to the second embodiment.
It is a control circuit diagram which controls the surface temperature of the fixing device which concerns on 2nd Embodiment. Note that the same components as those of the embodiment shown in FIG. 3 are designated by the same reference numerals, and duplicate description will be omitted.

In the figure, the input voltage discriminating means is constructed as follows. The conductive portion 14f such as a wire is
It is used for determining whether the power supply voltage specification of a unit such as a heater or a thermal fixing device is 100V system or 200V system. When the unit has 100V system voltage specification, FIG. ), The other end of the signal line whose one end is connected to the input port of the main control unit 31 is connected to the resistor 76.
Connected to the DC power source Vcc via
Ground via f. When the unit has a voltage specification of 200 V system, the other end of the signal line whose one end is connected to the input port of the main control unit 31 is connected to the DC voltage via the resistor 76 as shown in FIG. 7B. Connect to power supply Vcc.

Therefore, the conductive section 14f is connected to the input port of the main control section 31 in the 100V system unit, and the input signal of the main control section 31 becomes the L level by the connection with the main body of the apparatus, and the 200V system unit. Since the conductive portion 14f is not connected to the input port of the main control unit 31 in the unit, the input signal of the main control unit 31 goes to H level, which makes it possible to distinguish between 100V system and 200V system. In addition,
When determining the 100V system and the 200V system, the conductive portion 14f connected to the input port of the main control unit 31 is
The 100V system unit and the 200V system unit can be similarly identified even if the above embodiment is reversed.

After the input power supply voltages of the 100V system and the 200V system are discriminated in this way, the input power supply voltage to the heater 14c is controlled according to the flowchart shown in FIG. 4, whereby the rush current can be suppressed. It is possible to suppress flickering and the like of lighting devices connected to the same power supply device.

[0041]

As described above, according to the present invention,
While the heater driving means is being controlled by the fixing device control means, the input voltage is detected by the power supply voltage detecting means before the heater of the thermal fixing means is energized, and the fixing at the start of energization is carried out based on this input voltage. Since the drive of the heater drive means is controlled by the controller control means, it is possible to suppress a sudden voltage fluctuation due to the inrush current when the heater is energized and reduce the influence on other devices connected to the same power supply. it can.

Similarly, the input voltage is discriminated by the input voltage discriminating means, and the driving of the heater driving means by the fixing device control means at the start of energization is controlled based on the discriminated voltage. Inrush current to the means can be suppressed.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram showing an example of an image forming apparatus according to the present invention.

FIG. 2 is a control block diagram showing the printer control device of FIG.

FIG. 3 is a circuit diagram showing a power supply voltage detection circuit unit and a fixing device control circuit unit according to the first embodiment of the present invention.

FIG. 4 shows heater drive signals of the first and second embodiments, (a) is a heater drive signal waveform diagram of 200V system,
(B) is a 100 V system heater drive signal waveform diagram.

FIG. 5 is a flowchart showing first and second embodiments.

FIG. 6 is a circuit diagram showing a power supply voltage detection circuit section and a fixing device control circuit section according to a second embodiment of the present invention.

FIG. 7 shows an input voltage discriminating means of the present invention, in which (a) is 1
FIG. 7B is a circuit diagram when a unit having a voltage specification of 00V system is connected, and FIG. 7B is a circuit diagram when a unit having a voltage specification of 200V system is connected.

[Explanation of symbols]

14 Thermal Fixing Means (Fixing Device) 14c Heater 14f Input Voltage Discriminating Means (Conductive Section) 31 Main Control Section 42 Recording Medium (Recording Paper) 50 Power Supply Voltage Detecting Means (Power Supply Voltage Detecting Circuit Section) 51 Power Supply (Commercial Power Supply) 53 Heater driving means (solid state relay) 57 Fixing device control means (transistor) 62 Heater driving means (triac)

Claims (8)

[Claims] 1. A fixing device comprising: a heat fixing means for thermally fixing unfixed toner on a recording medium via a fixing member; and a power supply device for applying a power supply voltage to the heat fixing means. Heater driving means for driving the heater, and at the start of energization of the heater, the driving of the heater driving means is controlled on the basis of the input power supply voltage of the power supply device, and during normal fixing operation, the surface of the fixing member is And a fixing device control unit that controls driving of the heater driving unit so that the temperature becomes a predetermined temperature. 2. The fixing device according to claim 1, wherein the input power supply voltage of the power supply device is detected by a power supply voltage detecting means. 3. The fixing device according to claim 2, wherein the power supply voltage detecting means inputs a voltage having a waveform similar to a half wave of an AC waveform of the power supply device to the main control portion. 4. The fixing device according to claim 1, wherein the input power supply voltage of the power supply device is discriminated by the main control unit by an input voltage discriminating unit connected to the main control unit. 5. The fixing device according to claim 2, wherein the fixing device control unit includes the main control unit and a switching element that is on / off controlled by the main control unit. 6. The fixing device according to claim 1, wherein the heater driving unit is configured by connecting a solid state relay to a gate of a triac. 7. The fixing device according to claim 1, wherein the heater driving unit is driven by phase control of the fixing unit control unit. 8. The fixing device according to claim 1, wherein the heater driving unit is driven by the wave number control of the fixing unit control unit.