JP2005134918A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus realizing the shortening of warm-up time. <P>SOLUTION: The image forming apparatus has a driving control part (66) for driving and controlling the induction heating device (50) of a fixing device (40) and a main body control part (91) for controlling an entire electronic copying machine individually (independently). At the start-up time when power is supplied, start-up processing for the device (50) is started previous to that for other spots other than the device (50) in the main body of the electronic copying machine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  According to the present invention, a high frequency magnetic field is generated from a coil, and the high frequency magnetic field is applied to the heat generating member to generate an eddy current in the heat generating member, and the developer image on the recording medium is generated by the self-heating of the heat generating member based on the eddy current loss. The present invention relates to an image forming apparatus having a fixing device for fixing the toner.

  An image forming apparatus utilizing digital technology, a so-called electronic copying machine, exposes a document table on which a document is placed and outputs an image signal corresponding to the amount of light reflected from the document table from a CCD (charge transfer device) type line sensor. The photosensitive drum is irradiated with a laser beam corresponding to the image signal obtained from the line sensor to form an electrostatic latent image on the peripheral surface of the photosensitive drum, and the electrostatic latent image is charged in advance (negative polarity) The image is made visible by adhesion of the developer (toner) subjected to the above. A sheet is fed to the photosensitive drum in synchronization with the rotation of the photosensitive drum, and a visible image (developer image) on the photosensitive drum is transferred to the sheet. Thus, the sheet having the developer image transferred thereto is sent to the fixing device.

  The fixing device includes a heating roller and a pressure roller in contact with the heating roller. The developer image on the paper is fixed by heat of the heating roller while the paper is sandwiched between the rollers and conveyed. .

  An example of a heat source for the heating roller is an induction heating device. The induction heating device includes a coil housed inside a heating roller, and a high frequency generation circuit that supplies a high frequency current to the coil.

  The high frequency generation circuit includes a rectifier circuit that rectifies the voltage of the AC power supply, and a switching circuit that converts an output voltage (DC voltage) of the rectifier circuit into a high frequency of a predetermined frequency. The coil is connected to the output end of the high frequency generation circuit (the output end of the switching circuit).

  When the high frequency generating circuit operates, a high frequency current is supplied to the coil, and a high frequency magnetic field is generated from the coil. This high frequency magnetic field is applied to the heating roller, and an eddy current is generated in the heating roller. The heating roller self-heats based on the eddy current loss, and the developer image on the paper is fixed by the heat generation.

  However, in the electronic copying machine, when the startup process is performed when the power is turned on, the startup of the induction heating device takes longer than the startup of other parts.

  The start-up process for the induction heating apparatus is started after the start-up process for the other part of the main body of the electronic copying machine other than the induction heating apparatus is started.

  For this reason, there is a problem that it takes time to warm up.

  An object of the present invention is to reduce the warm-up time in consideration of the above circumstances.

  The image forming apparatus of the present invention has at least a heating member and a coil that generates a high-frequency magnetic field so as to generate this heating member eddy current, and has a fixing device that fixes a developer image on a recording medium. A rectifier circuit that rectifies the output of the commercial AC power supply, a switching circuit that converts the output rectified by the rectifier circuit into a high frequency of a predetermined frequency and outputs a high frequency to the coil, and a first control that controls the switching circuit A circuit, a second control circuit that is supplied with electric power from the commercial AC power source and controls a portion of the image forming apparatus other than the fixing device, and the first control circuit and the second control circuit are electrically connected. And an interface circuit that relays data transmission / reception between the first control circuit and the second control circuit while being electrically insulated. When the power source switch is turned on, the first control circuit and the second control circuit perform startup processing in parallel, and the first control circuit supplies a high-frequency output to the coil in advance. .

  The image forming apparatus of the present invention can shorten the warm-up time.

  The first embodiment of the present invention will be described below.

  FIG. 1 shows the internal configuration of an image forming apparatus such as an electronic copying machine.

  A document table 2 for placing documents is provided at the top of the main body 1, and an automatic document feeder 3 is provided on the document table 2. The automatic document feeder 3 automatically feeds documents one by one to the upper surface of the document table 2.

  A carriage 4 is provided on the lower surface side of the document table 2 so as to reciprocate. An exposure lamp 5 is provided on the carriage 4, and the carriage 4 moves forward while the exposure lamp 5 is lit, so that the entire surface of the document table 2 is exposed and scanned.

  By this exposure scanning, a reflected light image of the document placed on the document table 2 is obtained, and the reflected light image is passed through the reflection mirrors 6, 7, 8 and the zoom lens block 9 to charge the CCD (charge transfer device). ) Type line sensor (hereinafter referred to as CCD sensor) 10. The CCD sensor 10 outputs an image signal having a voltage level corresponding to the amount of received light. This image signal is sent to the laser unit 27. The laser unit 27 emits laser light corresponding to the image signal.

  A photosensitive drum 20 is rotatably provided in the main body 1. Around the photosensitive drum 20, a charging charger 21, a developing device 22, a transfer charger 23, a peeling charger 24, a cleaner 25, and a static eliminator 26 are sequentially arranged. Laser light emitted from the laser unit 27 passes between the charging charger 21 and the developing device 22 and is applied to the peripheral surface of the photosensitive drum 20.

  A plurality of paper feed cassettes 30 are provided at the bottom in the main body 1. These paper feed cassettes 30 each contain a large number of copy papers P as recording media.

  Each paper feed cassette 30 is provided with a pickup roller 31 for taking out the copy paper P one by one.

At the time of copying, the copy paper P is taken out one by one from any one of the paper feed cassettes 30. The taken copy paper P is separated from the paper feed cassette 30 by the separator 32 and sent to the registration roller 33, where it waits for the rotation of the photosensitive drum 20. The registration roller 33 feeds the copy paper P between the transfer charger 23 and the photosensitive drum 20 in synchronization with the rotation of the photosensitive drum 20.

  The photosensitive drum 20 rotates in the clockwise direction in the figure at the time of copying. The charging charger 21 applies a high voltage supplied from a high voltage power supply unit (not shown) to the photosensitive drum 20 to charge the surface of the photosensitive drum 20 with an electrostatic charge. An electrostatic latent image is formed on the photosensitive drum 20 by this charging and irradiation of the photosensitive drum 20 with laser light from the laser unit 27.

  The developing device 22 supplies a developer to the photosensitive drum 20. By supplying the developer, the electrostatic latent image on the photosensitive drum 20 is visualized. The transfer charger 23 transfers a visible image (developer image) on the photosensitive drum 20 to the copy paper P fed from the registration roller 33. After the transfer, the copy paper P is peeled off from the photosensitive drum 20 by the peeling charger 24. The peeled copy paper P is sent to the fixing device 40 by the transport belt 34.

  The fixing device 40 includes a heating roller 41 and a pressure roller 42. The developer image on the copy paper P is heated by the heat of the heating roller 41 while the copy paper P is sandwiched between the rollers and conveyed. To fix. The copy paper P that has passed through the fixing device 40 is discharged to the tray 36 by the transport roller 35. A specific configuration of the fixing device 40 is shown in FIG.

  A conductive heating roller 41 and a pressure roller 42 that is in rolling contact with the heating roller 41 in a pressurized state are provided at positions where the conveyance path of the copy paper P is vertically sandwiched. The rolling contact portions of both rollers 41 and 42 are maintained so as to have a constant nip width.

  The heating roller 41 is rotationally driven in the direction of the arrow. The pressure roller 42 receives the rotation of the heating roller 41 and rotates in the arrow direction. When the copy paper P passes through the rolling contact portion (fixing point) between the heating roller 41 and the pressure roller 42 and the copy paper P receives heat from the heating roller 41, the developer image T on the copy paper P is transferred. Is fixed on the copy paper P.

  A peeling claw 43 for peeling the copy paper P from the heating roller 41 around the heating roller 41, a cleaning member 44 for removing toner and paper dust remaining on the heating roller 41, and a surface temperature Tr of the heating roller 41 are detected. A release agent application device 46 for applying a release agent to the thermistor 45 and the surface of the heating roller 41 is provided.

  An induction heating device 50 is accommodated in the heating roller 41 as a heat source. The induction heating device 50 includes a core 51 and a coil 52 attached to the core 51, generates a high frequency magnetic field from the coil 52, and induction heats the heating roller 41 by the high frequency magnetic field.

  That is, when a high frequency current is supplied to the coil 52 from a high frequency generation circuit 61 described later, a high frequency magnetic field is generated from the coil 52, and an eddy current is generated in the heating roller 41 by this high frequency magnetic field. Based on the eddy current loss due to the resistance, the heating roller 41 self-heats.

  As shown in FIG. 3, support members 53 are attached to both ends of the core 51, and the support members 53 are fixed to a fixing metal plate (not shown) of the main body 1. By these support members 53, the induction heating device 50 is supported separately from the heating roller 41.

  As shown in FIG. 4, electric wires (so-called lead wires) 52 a and 52 b are led out from both ends of the coil 52, and the electric wires 52 a and 52 b are connected to the circuit board 60 on the induction heating device 50 side. And the shield member 70 for shielding the electric wires 52a and 52b magnetically is provided in the state surrounding the electric wires 52a and 52b.

  As shown in FIG. 5, the circuit board 60 includes input terminals 61 a and 61 b connected to a commercial AC power supply 80, a high frequency generation circuit 61 connected to the input terminals 61 a and 61 b, and an output terminal of the high frequency generation circuit 61. Output terminals 64a and 64b connected to the input terminal, a constant voltage circuit unit 65 connected to the input terminals 61a and 61b, a drive control unit 66 connected to the output terminal of the constant voltage circuit unit 65, the drive control unit 66 and the main body An interface circuit 67 for performing data transmission / reception with the control unit 91 of the side circuit board 90 in an insulated state, and an input terminal 68 for taking the detected temperature data of the thermistor 45 into the drive control unit 66 are provided.

  The rectifier circuit 62 rectifies the voltage of the commercial AC power supply 80. The switching circuit 63 converts the output voltage (DC voltage) of the rectifier circuit 62 into a high frequency having a predetermined frequency. The constant voltage circuit unit 65 adjusts and outputs the output voltage of the rectifier circuit 62 to a certain level suitable for the operation of the drive control unit 66. The drive control unit 66 controls driving of the switching circuit 63 in accordance with a command sent from the control unit 91 of the main body side circuit board 90.

  The electric wires 52 a and 52 b are connected to the output terminals 64 a and 64 of the circuit board 60.

  The main body side circuit board 90 is connected to a commercial AC power supply 80. In addition to the control unit 91, each electric circuit unit of the main body 1 is mounted on the main circuit board 90.

  As shown in FIG. 6, the interface circuit 67 includes photodiodes D1 and D2, phototransistors T1 and T2, resistors R2, R3, and R4 provided on the circuit board 60 on the induction heating device 50 side. . The photodiode D1 and the phototransistor T1, and the photodiode D2 and the phototransistor T2 constitute a photocoupler. Thus, the phototransistor T1 is turned on when the photodiode D1 is turned on, and the phototransistor T2 is turned on when the photodiode D2 is turned on.

  An output signal from the output end 91a of the control unit 91 of the main body side circuit board 90 is supplied to the anode of the photodiode D1 via a resistor R1 on the main body side circuit board 90 side. The power source voltage VDD from the main body side circuit board 90 is applied to the cathode of the photodiode D1.

  Thus, the photodiode D1 is turned on and off in accordance with the output signal from the output end 91a of the control unit 91.

  The phototransistor T1 and the resistor R2 form a series circuit. The input end 66a of the drive control unit 66 is connected to the connection point between one end of the resistor R2 and the cathode of the phototransistor T1, and the other end of the resistor R2 is connected to the other end. Is supplied with the power supply voltage VCC, and the anode of the phototransistor T1 is grounded.

  As a result, a signal corresponding to whether the phototransistor T1 is on or off is supplied to the input terminal 66a of the drive control unit 66.

  An output signal from the output end 66b of the drive control unit 66 is supplied to the anode of the photodiode D2 via a resistor R3. A power supply voltage VCC is applied to the cathode of the photodiode D2.

  Thus, the photodiode D2 is turned on and off in accordance with the output signal from the output end 66b of the drive control unit 66.

  A series circuit is configured by the phototransistor T2 and the resistor R4, and an input end 91b of the control unit 91 of the main body side circuit board 90 is connected to a connection point between one end of the resistor R4 and the cathode of the phototransistor T2, and the resistor R4 The power supply voltage VDD from the main body side circuit board 90 is applied to the other end of the phototransistor, and the anode of the phototransistor T2 is grounded.

  As a result, a signal corresponding to whether the phototransistor T2 is turned on or off is supplied to the input terminal 91b of the control unit 91.

  According to such a configuration, a service mode notification signal (L level) is output from the output terminal 91 a of the control unit 91. Then, the power supply voltage VDD from the main body side circuit board 90 is applied to the series circuit of the photodiode D1 and the resistor R1, and the photodiode D1 is turned on. By this lighting, the phototransistor T1 is turned on, whereby the power supply voltage VCC on the circuit board 60 side of the induction heating device 50 is applied to the series circuit of the phototransistor T1 and the resistor R2, and the service is applied to the input terminal 66a of the drive control unit 66. A mode notification signal (L level) is supplied.

  Based on the supply of the service mode notification signal, the drive control unit 66 interrupts the start-up process.

  In addition, the drive control unit 66 outputs a status signal from the output terminal 66a. When an error such as a power failure occurs, an H level signal is output, and when normal, an L level signal is output.

  In other words, an L level signal is output from the output end 66a of the drive control unit 66 during normal operation. As a result, the power supply voltage VCC on the circuit board 60 side of the induction heating device 50 is applied to the series circuit including the photodiode D2 and the resistor R3, and the photodiode D2 is turned on. By this lighting, the phototransistor T2 is turned on, whereby the power supply voltage VDD from the main body side circuit board 90 is applied to the series circuit of the phototransistor T2 and the resistor R4, and the status indicating normality at the input terminal 91b of the control unit 91 A signal (L level) is supplied.

  Further, when an error (error) occurs, an H level signal is output from the output end 66a of the drive control unit 66. Then, the power supply voltage VCC on the circuit board 60 side of the induction heating device 50 is not applied to the series circuit including the photodiode D2 and the resistor R3, and the photodiode D2 remains off. As a result, the phototransistor T2 remains off, and the power supply voltage VDD from the main body side circuit board 90 is not applied to the series circuit of the phototransistor T2 and the resistor R4, and the input terminal 91b of the control unit 91 is abnormal (error). A status signal (H level) is supplied.

  The drive control unit 66 determines an abnormality of the input power supply, an abnormality of each circuit unit, and an abnormality (disconnection) of the coil.

  As described above, the operation control unit 66 on the circuit board 60 side of the induction heating device 50 of the fixing device 40 and the control unit 91 of the main body side circuit board 90 are separated by the photocoupler in the interface circuit 67 and insulated. Has been.

  Thereby, the power supply voltage VCC (100 volts) on the circuit board 60 side and the power supply voltage VDD (24 volts) on the main body side circuit board 90 can be separated and insulated, and even if an abnormality occurs on the circuit board 60 side, It is possible to prevent the power supply voltage VCC from flowing into the main body side circuit board 90 and causing a failure.

  Next, the startup process when the power is turned on will be described with reference to the flowchart shown in FIG.

  That is, when a power switch (not shown) is turned on (when the power is turned on), the startup process by the control unit 91 of the main body side circuit board 90 and the operation control unit 66 on the circuit board 60 side of the induction heating device 50 of the fixing device 40 are performed. The startup process is performed in parallel.

  First, the operation control unit 66 starts the start-up process, that is, the supply of the high-frequency current to the coil 52 when the power is turned on (ST1). Next, the operation control unit 66 determines whether or not a service mode is notified from the control unit 91 (ST2). As a result of this determination, when there is no notification of the service mode, the operation control unit 66 continues the startup process (ST3).

  Further, when the operation control unit 66 is operating normally without judging an error, the operation control unit 66 notifies the control unit 91 of the main body side circuit board 90 of this status (ST4). Further, when determining an error, the operation control unit 66 notifies this status to the control unit 91 of the main circuit board 90 (ST4). When this error occurs, the operation control unit 66 stops the start-up process, that is, the supply of the high-frequency current to the coil 52 (ST5).

Further, when determining the notification of the service mode in step 2, the operation control unit 66 interrupts (stops) the start-up process, that is, the supply of the high-frequency current to the coil 52 (ST6).
Further, when the power is turned on, the control unit 91 starts a start-up process, that is, a start-up process at a location other than the induction heating device 50 of the fixing device 40 (ST21). Further, the control unit 91 determines whether or not the service mode is selected (ST22). When the service mode is selected, the service mode notification is sent to the operation control unit 66 on the circuit board 60 side of the induction heating device 50. Supplied (ST23).

  Thereafter, the control unit 91 performs error processing when an error signal is supplied from the operation control unit 66 of the induction heating apparatus 50 (ST24).

  Moreover, the control part 91 judges that it is a pre-run start temperature when the detected temperature from the thermistor 45 reaches a predetermined temperature in a state where a normal signal is supplied from the operation control part 66 of the induction heating device 50 (ST25). The pre-run process is started (ST26). That is, the control unit 91 rotates the heating roller 41 of the fixing device 40 to make the entire surface temperature of the heating roller 41 uniform. Thereafter, the control unit 91 enters a ready state when other initial processing is completed.

  As described above, the control unit for driving and controlling the induction heating device of the fixing device and the main body control unit for controlling the entire electronic copying machine are provided separately (independently). The start-up process is started prior to the start-up process for other parts of the main body of the electronic copying machine other than the induction heating device.

  Thereby, the warm-up time can be shortened.

  Further, when the fixing device is abnormal, the control unit on the fixing device side can determine the abnormality.

  In addition, the fixing device is started in parallel with the start-up of the electronic copying machine main body other than the above-described induction heating device.

  Further, the start-up process for the fixing device is stopped (interrupted) in the adjustment mode by the service person or when the fixing jam is restored. Accordingly, since it is dangerous if the temperature of the fixing device rises regardless of the main body, depending on the state of the main body of the electronic copying machine at the time of starting, the start-up process for the fixing device is stopped (safety measure).

  The control unit on the fixing device side and the control unit on the main body side of the electronic copying machine are separated by a photocoupler in the interface circuit and insulated.

  In the first embodiment, the case where the drive control unit of the induction heating device of the fixing device executes the start-up process independently of the control unit of the main body of the electronic copying machine has been described. As a second embodiment, the same can be applied to the case where the start-up process in the drive control unit of the induction heating device of the fixing device is controlled in the control unit of the main body of the electronic copying machine.

  In this case, the configuration of FIGS. 1 to 6 is the same. However, the signal from the output end 91a is changed to a signal indicating the supply and stop of the high frequency current to the coil 52 to the control unit 91 of the main body side circuit board 90. For example, at the L level, the high frequency current to the coil 52 is This indicates supply, and when the signal is at the H level, the high-frequency current to the coil 52 is stopped.

  Next, the startup process when the power is turned on will be described with reference to the flowchart shown in FIG.

  That is, when a power switch (not shown) is turned on (when the power is turned on), start-up processing by the control unit 91 of the main body side circuit board 90, that is, start-up processing of a portion other than the induction heating device 50 of the fixing device 40 is started. The operation controller 66 on the circuit board 60 side of the induction heating device 50 is notified of the supply of high-frequency current to the coil 52 (ST31).

  Thereby, the operation control unit 66 starts the start-up process, that is, the supply of the high-frequency current to the coil 52 in response to the notification.

  The operation control unit 66 notifies the control unit 91 of the main circuit board 90 of this status when operating normally without judging an error. Further, when the operation control unit 66 determines an error, the operation control unit 66 notifies the control unit 91 of the main body side circuit board 90 of this status.

  When the error signal is not supplied from the operation control unit 66 of the induction heating device 50 (ST32) and the service mode is not selected (ST33), the control unit 91 sets the detected temperature from the thermistor 45 to a predetermined temperature. When the temperature has reached, the pre-run start temperature is determined (ST34), and the pre-run process is started (ST35). That is, the control unit 91 rotates the heating roller 41 of the fixing device 40 to make the entire surface temperature of the heating roller 41 uniform. Thereafter, the control unit 91 enters a ready state when other initial processing is completed.

  In addition, when an error signal is supplied from the operation control unit 66 of the induction heating device 50 in the above step 32, the control unit 91 performs error processing and applies a coil to the operation control unit 66 on the circuit board 60 side of the induction heating device 50. The stop of the high-frequency current to 52 is notified (ST36).

  Thereby, the operation control unit 66 stops the start-up process, that is, the supply of the high-frequency current to the coil 52.

  Further, when the service mode is selected in step 33, the control unit 91 notifies the operation control unit 66 on the circuit board 60 side of the induction heating device 50 that the high-frequency current to the coil 52 is stopped (ST36). Perform service mode processing.

  Thereby, the operation control unit 66 stops the start-up process, that is, the supply of the high-frequency current to the coil 52.

1 is a diagram illustrating an overall configuration of an electronic copying machine. FIG. 3 is a diagram illustrating a configuration of a fixing device. The figure which shows the structure of the principal part of an induction heating apparatus. The figure which shows the connection of an induction heating apparatus and a circuit board. The block diagram of the electric circuit of an induction heating apparatus and a main body. The block diagram which shows schematic structure of an interface circuit. The flowchart for demonstrating the starting process at the time of the power-on in a 1st Example. The flowchart for demonstrating the starting process at the time of the power-on in a 2nd Example.

Explanation of symbols

  40: fixing device, 50 ... induction heating device, 66 ... drive control unit, 91 ... main body control unit

Claims (6)

In an image forming apparatus having at least a heating member and a coil that generates a high-frequency magnetic field so as to generate this heating member eddy current, and having a fixing device that fixes a developer image on a recording medium.
A rectifier circuit for rectifying the output of the commercial AC power supply;
A switching circuit that converts the output rectified by the rectifier circuit to a high frequency of a predetermined frequency and outputs the high frequency to the coil;
A first control circuit for controlling the switching circuit;
A second control circuit that is supplied with electric power from the commercial AC power source and controls a portion of the image forming apparatus other than the fixing device;
An interface circuit that relays data transmission and reception between the first control circuit and the second control circuit while electrically insulating the first control circuit and the second control circuit;
When the commercial AC power supply is turned on, the first control circuit and the second control circuit perform startup processing in parallel, and the first control circuit outputs a high frequency output to the coil. An image forming apparatus that is supplied in advance.   The image forming apparatus according to claim 1, wherein the first control circuit further includes a determination unit that determines abnormality of the fixing device. Setting means for setting a service mode for performing maintenance on the image forming apparatus;
2. The image forming apparatus according to claim 1, wherein when the service mode is set by the setting means, the first high-frequency output supply to the coil by the first control circuit is stopped.   2. The image forming apparatus according to claim 1, wherein the interface circuit comprises a transmitting-side photodiode and a receiving-side phototransistor. 2. The image according to claim 1, wherein the first control means stops the high-frequency output supplied to the coil by the first control circuit in accordance with a signal from the second control means. Forming equipment.   2. The image forming apparatus according to claim 1, wherein power supply voltages supplied to the first control circuit and the second control circuit are different.

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