JP2006343549A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of changing control sequence according to detection result of a voltage detection circuit to prevent the occurrence of abnormality in an AC power supply and the apparatus. <P>SOLUTION: In a power supply device provided with a power factor improving circuit, AC voltage detection is performed while the power factor improving circuit is stopped or blocked. In the image forming apparatus, the control sequence is determined according to the detection results of the AC voltage detection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus including a soft-start SW diversion switching power supply device including at least a rectifier circuit, a booster circuit, and a DC / DC converter circuit, and includes control means for controlling the load and power supply of the device. More specifically, the present invention relates to a device having a driving system such as a fixing device and a plurality of motors and actuators and having several load output modes when the driving system is not operating, such as a laser printer.

  In an image forming apparatus having a fixing device and a plurality of drive electric devices (for example, a motor, an actuator, etc.) such as a printer, a copier, and a facsimile using an electrophotographic process, it is required to improve the printing speed and shorten the operation start time. Yes. For this reason, the power supplied to the fixing device and the driving load tends to increase, and accordingly, the power supply device in the apparatus is required to have a large power capacity and high efficiency.

  However, the power that can be supplied from the commercial power source to the image forming apparatus generally has an upper limit of 15A in Japan, for example, and this standard cannot be satisfied by simply increasing the capacity of the power source device. It is necessary to add a circuit. Conversely, by using a high power factor power supply, the power input to the fixing unit can be used effectively. Therefore, in a device that requires a large amount of power for the drive device, a power factor improvement circuit is provided in the power supply device. There are many cases. The power factor correction circuit used in such a high power power supply device is generally a boost type, and the effect is not only the power factor improvement but also the effect of reducing the harmonic components of the input power supply. Have.

  On the other hand, although the apparent power can be reduced and the input current can be reduced by using a power factor correction circuit such as a boost converter, the upper limit of the input current is that the load power available to the entire device varies due to fluctuations in the commercial power supply voltage. It means to end up.

  For example, when the commercial power supply voltage is reduced from AC 100 V to AC 80 V at the input current upper limit 15 A, the apparent power that can be used by the device is reduced from 1500 W to 1200 W, and the power that can be used by the device is also reduced by 300 W.

  Therefore, in an image forming apparatus that requires large-capacity power, it is not sufficient to provide a power factor correction circuit to effectively use power that can be used from a commercial power supply while ensuring safety. Accordingly, it is necessary to change or stop the power supplied to the fixing device and the driving load.

  In addition, the power supply device may continue to operate as it is even if the power supply voltage drops below 100 VAC. In this case, a large amount of current continues to flow through the primary circuit in the power supply device, and there is a concern that the components in the device cannot be used within the rating.

Therefore, there is a method in which voltage detection means for the power supply is provided in the input section of the induction heating power supply, and the cutoff circuit of the power input section is operated when the detection result is abnormal (for example, see Patent Document 1 below). This method is very effective in preventing the AC power source from exceeding the current limit by stopping the induction heating means by detecting abnormality of the AC voltage and improving the safety of the induction overheating means.
JP 2003-295644 A

  In the above conventional examples, the input voltage is also detected and the load control is changed so as not to exceed the upper limit of the input current. The reliability is improved such as breaker cutoff prevention and power supply failure prevention, and the power is effective. It is very effective for use.

  In such a power supply that requires a large amount of power, a power factor correction circuit is required, and the output waveform after rectification is boosted by the power factor correction circuit to keep the AC voltage constant. A method of rectifying the previous pulsating flow is common.

  If an input detection circuit is to be provided after rectification and before boosting, the rectified waveform becomes a ripple waveform due to the operation of the power factor correction circuit, and AC voltage may be affected by problems such as PFC switching noise and voltage fluctuations due to the secondary load current. The accuracy of the detection voltage is degraded. For this reason, it is common to provide an AC voltage detection circuit at the power supply device input section. However, if a circuit is provided before rectification, a diode and a large-capacitance capacitor corresponding to the power supply frequency are required, which is problematic in terms of location and cost. It was. Further, when a voltage detection circuit is provided in the input section, power is always consumed when the power supply SW is turned off. For this reason, for example, a double-cut type that can cut off each phase of the power supply SW is required. From the viewpoint of energy saving, power is always consumed even though the voltage detection function is not required in the energy saving mode.

  As described above, in order to detect the input AC voltage of the power supply device provided with the power factor correction circuit in the conventional method, it is not perfect for cost, location, and energy saving.

  An object of the invention according to the present application is an image forming apparatus having a power supply device having a rectifier circuit, a power factor correction circuit, and a DC / DC converter circuit. It is an object of the present invention to provide an image forming apparatus that performs voltage detection and determines a control sequence according to the detection result.

  In order to achieve the above object, the image forming apparatus of the present invention is as follows.

  According to the first aspect of the present invention, in the power supply device including the power factor correction circuit, AC voltage detection is performed in a state where the power factor correction circuit is stopped and shut off, and a control sequence is performed according to the detection result of the AC voltage detection. It is characterized by determining.

  According to a second aspect of the present invention, the AC voltage detection is performed when the power is turned on, when returning from the energy saving mode, or during the energy saving mode.

  According to a third aspect of the present invention, the AC voltage detection is performed after AC voltage rectification.

  According to a fourth aspect of the present invention, the AC voltage detection utilizes a switching waveform.

  According to a fifth aspect of the present invention, in a power supply device including an AC voltage input cutoff means and a power factor correction circuit, AC voltage detection is performed in a state where the power factor improvement circuit is stopped and shut off, and the detection result of the AC voltage detection The AC voltage input is determined to be cut off according to the above.

  In the invention according to claim 6, in the power supply device including the AC voltage input cutoff means, the power factor correction circuit, and the soft start switch, the AC voltage is detected in a state where the power factor improvement circuit is stopped and shut off, and the AC voltage is detected. It is determined that the AC voltage input is cut off according to the detection result of the detection, and the abnormality detection result is displayed before the cutoff.

  According to the seventh aspect of the present invention, in a power supply device including an AC voltage input cutoff means, a power factor correction circuit, and a soft start switch, the AC voltage is detected in a state where the power factor improvement circuit is stopped and shut off, and the AC voltage is detected. The control sequence is determined based on the detection result of the detection, and the detection result is left as a history in a storage device.

  According to the present invention, according to the first aspect of the present invention, it is possible to execute the control sequence of the optimum image forming apparatus based on the highly accurate AC voltage detection result.

  According to the invention of claim 2, in addition to the effect of the invention of claim 1, it is possible to detect an AC voltage under a stable load condition.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1, it is possible to directly detect the voltage after rectification and to improve the voltage detection accuracy.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1, the waveform can be detected by a simple and inexpensive method by using the switching waveform.

  According to the fifth aspect of the present invention, it is possible to prevent a circuit component failure in the power supply device when it is determined that the AC voltage detection value is abnormal.

  According to the sixth aspect of the present invention, it is possible to detect abnormality for the user.

  According to the invention of claim 7, it is possible to improve the maintainability of the apparatus by storing the AC voltage detection result.

  FIG. 2 is an exemplary configuration diagram of the image forming apparatus according to the present embodiment. Here, a laser beam printer will be described as an example of an image forming apparatus. However, an apparatus having a plurality of driving devices (for example, a motor, an actuator, etc.) and having a power supply device including a relatively large capacity power factor correction circuit. The present invention can be applied to any device that has a plurality of operation modes such as a state in which the drive device is stopped in addition to a state in which the drive device is always operated, such as a standby state and a low power state. Accordingly, it goes without saying that the present invention is applicable to apparatuses other than laser beam printers.

  In the image forming apparatus 200 shown in FIG. 2, the recording medium 201 is fed toward the intermediate transfer member 203 by the feeding roller 202. The photosensitive drum 204 is driven to rotate counterclockwise at a predetermined speed by the power of a drive motor (not shown). During the rotation process, the photosensitive drum 204 is uniformly charged by the primary charger 205. The laser beam scanner 206 outputs a laser beam modulated in accordance with the image signal, and selectively scans and exposes the photosensitive drum 204 to form an electrostatic latent image. The developing device 207 attaches powder toner, which is a developer, to the electrostatic latent image by the sleeve 208 to form a toner image (developer image). The toner image formed on the photosensitive drum 204 is transferred onto an intermediate transfer member 203 that rotates in contact with the photosensitive drum 204. The recording medium 201 is conveyed according to an appropriate timing synchronized with the rotation of the intermediate transfer member 203. The recording medium 201 is pressed against the intermediate transfer member 203 by a transfer roller 209 to which a transfer bias is applied, and the toner image is transferred onto the recording medium 201. The fixing device 210 includes a fixing roller 212 including a heating unit 211 and a pressure roller 213 for pressing the recording medium against the fixing roller 212. The toner image is fixed by heating and pressurizing the recording medium 201. The recording medium 201 on which the toner image is fixed is discharged out of the apparatus as an image formed product. DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The power supply device 215 connected to the commercial power supply 214 functions as a power supply unit having a rectifying action from AC to DC. The electric power consumed in the above process is normally supplied from the power supply device 215 to each load circuit in the image forming apparatus 200.

  Many OA devices using electrophotographic technology such as such an image forming apparatus consume a large amount of power from the viewpoint of power consumption. For example, the fixing device 210 alone consumes power of 600 W to 1000 W. Is. In addition to the recent increase in the speed of the apparatus, when a large number of attached units such as a duplex printing option, a paper discharge option, and an image scanner option are added, the power consumption of the drive system other than the fixing device is increasing. Therefore, it is necessary to provide a power factor correction circuit in the power supply device in order to effectively use the current so as not to exceed the current upper limit of the commercial power supply 214. The power supply device 215 which is one of the features of the present embodiment includes a rectifying element, a power factor improving circuit as a power factor improving action, and a DC / DC converter. The DC / DC converter is, for example, a forward method or a flyback method. Various converter methods such as a half-bridge method can be applied.

  FIG. 1 is a circuit diagram showing a main part of a power supply device 215 according to an embodiment of the present invention. As shown in FIG. 1, the power supply device 215 is provided with a power factor correction circuit. The power factor correction circuit includes a choke coil 102, a diode 104, a rectifying capacitor 105, a switching element 103, and a power factor improvement IC 107 that is a control IC thereof. The control unit 114 can turn on / off the power factor correction IC 107. To do. The on / off control 109 of the power factor improvement IC 107 may control the on / off control terminal of the power factor improvement IC 107, or control the power supply line to the power factor improvement IC 107 to be cut directly from the viewpoint of energy saving. May be. In the case of a flyback power supply device as shown in FIG. 1, the AC voltage detection circuit 110 may detect and detect the drain-source voltage of the switching element 106. In order to secure the creeping distance between the primary and secondary of the power supply device, the switching output is output to the secondary side by a photocoupler, and after being rectified by the secondary side circuit, it may be detected by the AD converter. In addition, although this circuit example shown in FIG. 1 is of a single converter system, it can also be used in a multi-converter output power source.

  FIG. 3 shows an example of an operation sequence of the power supply apparatus 215 that leads to determination of the control sequence of the image forming apparatus when the power supply SW is on. This sequence is illustrated when the power supply SW is turned on as an example. However, this sequence is very effective when returning from the power factor correction circuit stop state such as when returning from the sleep mode, and the load fluctuation of the power supply device is not so large. Can be diverted. First, the operation of the power supply device 215 immediately after the power supply SW is turned on will be briefly described. When the power supply SW is turned on, the power supply IC 108 is first activated to operate the switching element 103. When the transformer is operated by the switching waveform by the operation of the switching element 103 and rectification is performed on the secondary side, a power output is obtained. Thereafter, the control unit 114 operates to enable on / off control control of the power factor correction IC 107.

  The controller 114 turns off the power factor correction IC 107 by the on / off control 109 before detecting the AC voltage, and stops the boosting operation. This operation can be omitted when the power factor correction IC is set to OFF in the initial operation. Here, since the image forming apparatus is before the start of the initial operation, most of the load is an arbitrary constant load condition determined by the operation of the control unit or the like. Since the boosting operation is stopped, the drain-source voltage when the switching element 106 is on can be output corresponding to the input AC voltage. Here, the switching waveform of the switching element 106 is driven at a frequency several hundred times higher than the power supply frequency. Therefore, the capacitor capacity of the detection circuit can be made smaller than the case where a voltage detection circuit is provided at the input portion of the AC power supply 100, and space and cost can be reduced.

  When an abnormality is detected in the result of the voltage detection circuit 110, for example, when it is detected that the voltage is 100 V AC or less, the control of the image forming apparatus is changed so that the upper limit of the input current of the AC power supply 100 is not exceeded. For example, it is better to reduce the power input to the fixing unit or reduce the driving system load when an abnormality occurs. Conversely, when no abnormality is found in the result of the voltage detection circuit 110, the normal image forming apparatus is controlled.

  Although only one converter is described in FIG. 1, for example, a control unit converter and a drive unit converter may be combined. In that case, it will be possible to improve the accuracy of the output voltage by stopping the drive converter and operating only the control converter to detect the AC voltage.

  In the second embodiment of the present invention, since the configuration of the image forming apparatus is the same as that of the first embodiment, description thereof will be omitted, and only the power supply device block diagram of the image forming apparatus will be described with reference to FIG. It explains using.

  As shown in FIG. 4, when the control unit 114 determines that the voltage of the AC power supply is detected by the input voltage detection circuit 110 and detects an abnormality based on the detection result, the input line from the AC power supply 100 is connected to the switch (AC power supply cutoff circuit) 400. Disconnect the power supply to prevent power supply failure. The basic configuration is the same as that of the first embodiment, and the AC voltage is detected from the switching waveform of the flyback converter. As described in the first embodiment, the load power when the power supply SW is turned on or when the energy saving mode is restored is substantially constant, and the power factor correction IC 107 is stopped to enable highly accurate detection.

  When it is detected that the AC voltage detection result is abnormal, the switch 400 is immediately turned off to prevent a circuit component failure in the power supply apparatus. For example, when it is determined that the value is higher than an arbitrary setting value in a 100 V system power supply device, it can be determined that the 200 V AC power supply is turned on and the input line can be disconnected, or conversely, it is determined that it is lower than the arbitrary setting value. In this case, it is possible to prevent a circuit component failure of the power supply device due to an increase in the primary current of the power supply device. Furthermore, if the power switch SW is a soft switch, it may be possible for the user to detect an abnormality on the display.

  In the third embodiment of the present invention, since the configuration of the image forming apparatus is the same as that of the first embodiment, the description thereof will be omitted, and only the power supply device block diagram of the image forming apparatus will be described with reference to FIG. It explains using.

  As shown in FIG. 4, when the control unit 114 determines that the voltage of the AC power supply is detected by the input voltage detection circuit 110 and detects an abnormality based on the detection result, the input line from the AC power supply 100 is disconnected by the switch 400, and the power supply device Preventing malfunctions. The basic configuration is the same as that of the first embodiment, and the AC voltage is detected from the switching waveform of the flyback converter. As described in the first embodiment, the load power when the power supply SW is turned on or when the energy saving mode is restored is substantially constant, and the power factor correction IC 107 is stopped to enable highly accurate detection.

  On the other hand, the power supply environment of the image forming apparatus varies depending on the installation location. Line-to-line voltage fluctuations may occur due to the effects of power supply abnormalities in other systems, power supply abnormalities in the local system, and so on. Stopping the image forming apparatus due to frequent power failure is extremely troublesome for the user because it repeatedly initializes and causes in-machine jam processing.

  Therefore, in this embodiment, the state and the number of times when the power supply is abnormal are recorded in the storage device 500. According to this configuration, it is possible to display a power supply abnormality to the user and prompt improvement, and it is possible to provide an image forming apparatus effective for maintenance by a service person.

1 is a schematic circuit diagram of a power supply device according to Embodiment 1 of the present invention. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a flowchart of the sequence of the alternating voltage detection which concerns on Example 1 of this invention. It is a schematic circuit diagram of the power supply device which concerns on Example 2 of this invention. It is a schematic circuit diagram of the power supply device which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 AC power supply 101 Rectification bridge 102 Choke coil 103 Switching element 104 Diode 105 Rectification capacitor 106 Switching element 107 Power factor improvement IC
108 Power IC
109 Power Factor Improvement IC ON / OFF Control Circuit 110 AC Voltage Detection Circuit 111 Secondary Side Rectifier Diode 112 Secondary Smoothing Capacitor 113 Load 114 Control Unit 200 Image Forming Apparatus 201 Recording Medium 202 Feed Roller 203 Intermediate Transfer Member 204 Photosensitive Drum 205 Primary charger 206 Laser beam scanner 207 Developer 208 Sleeve 209 Transfer roller 210 Fixing device 211 Heating unit 212 Fixing roller 213 Pressure roller 214 Commercial power supply 215 Power supply device 300 AC input filter circuit 400 Switch (AC power supply cutoff circuit)
500 storage devices

Claims (7)

  In the power supply device provided with the power factor correction circuit, an AC voltage is detected in a state where the power factor improvement circuit is stopped and shut off, and a control sequence is determined according to a detection result of the AC voltage detection. Forming equipment.   The image forming apparatus according to claim 1, wherein the AC voltage detection is performed when the power is turned on, when returning from the energy saving mode, or during the energy saving mode.   The image forming apparatus according to claim 1, wherein the AC voltage detection is performed after AC voltage rectification.   The image forming apparatus according to claim 1, wherein the AC voltage detection uses a switching waveform.   In a power supply apparatus equipped with AC voltage input cutoff means and a power factor correction circuit, AC voltage detection is performed with the power factor correction circuit stopped and shut off, and AC voltage input is shut off according to the detection result of the AC voltage detection. An image forming apparatus characterized by determining to do.   In a power supply device having an AC voltage input cutoff means, a power factor correction circuit, and a soft start switch, AC voltage detection is performed in a state where the power factor improvement circuit is stopped and shut off, and an AC voltage is detected according to the detection result of the AC voltage detection. An image forming apparatus that determines to block voltage input and displays an abnormality detection result before blocking.   In a power supply apparatus having an AC voltage input cutoff means, a power factor correction circuit, and a soft start switch, AC voltage detection is performed in a state where the power factor improvement circuit is stopped and shut off, and a control sequence is determined based on the detection result of the AC voltage detection. An image forming apparatus comprising: determining and leaving the detection result as a history in a storage device.

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