JP2010148228A - Motor control apparatus of image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the number of components, an arrangement space and cost rise by suppressing a redundant circuit which is attached to a motor driving circuit of an image forming apparatus and operates when an element is abnormal. <P>SOLUTION: A switching means used only for reducing energy consumption of the image forming apparatus is made to perform a load stop operation when a rotational frequency of a motor is abnormal due to the fault of the driving circuit. In the image forming apparatus loading a plurality of converters, the load stop operation when the rotational frequency of the motor is abnormal due to the fault of the driving circuit is shared by a starting/stop operation of the converter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device and a control method for an apparatus load driving motor in an image forming apparatus, and more particularly, to an abnormality detection method for a motor and a motor driving circuit.

  As a conventional processing method when the rotational speed of the motor and the drive circuit is abnormal, there is a method in which processing is performed when the switching means prepared separately other than the element that performs the switching operation of the motor is made non-conductive (for example, patent) Reference 1).

Hereinafter, a conventional example will be described with reference to FIG. FIG. 6 is a diagram for simply explaining a conventional example. Switching means 602 and switching elements 603 are arranged on both sides of a motor 601, and a converter output is input to the switching means 602. The motor 601 is rotationally driven by the conduction and switching element 603 performing a switching operation. Although not described in detail, the rotation speed detection signal 604 is output from the rotation speed detection means, and a constant speed control is executed by the microcontroller 605 by performing a comparison operation between the rotation speed detection signal 604 and the target speed. A PWM drive signal 606 is a drive signal output from the microcontroller 605 for PWM driving the switching element 603, and a switching signal 607 is a drive signal for performing conduction control of the switching means. If the rotation speed detection signal 604 continues to be higher than the target rotation speed despite the constant speed control by the PWM drive signal 606, the switching means 602 is turned off by the switching signal 607. The process at the time of abnormality is performed.
JP 2002-27605 A

  2. Description of the Related Art In recent years, recording apparatuses such as image forming apparatuses have been equipped with an optional cassette function for improving usability such as a double-sided printing function aiming at saving paper resources and a stapler. With this background, the number of motors and drive circuits used for document conveyance, latent image formation, and the like is increasing, and the complexity of the system is increasing. In addition, the circuit scale is increased because of the necessity of adding a redundant circuit to the motor drive circuit as shown in the prior art in order to protect against abnormal operation.

  As described above, there are the following problems due to the increase in the number of motors used per apparatus, the number of drive circuits, and the number of redundant circuits in order to improve the functions of the image forming apparatus.

  -Since the size of the drive circuit increases, an increase in the component arrangement space becomes an obstacle to the realization of downsizing of the device itself.

  -It is uneconomical because it is difficult to reduce costs due to an increase in the number of parts due to an increase in circuit scale.

In order to achieve the above object, a first invention according to the present application includes a plurality of DC outputs, a motor for driving an apparatus load, a rotation speed detection means for detecting a rotation speed of the motor, and the rotation speed detection means. The calculation control means for controlling the input power control means for controlling the input power to the motor so as to rotate the motor at a constant speed by counting the speed information and performing a comparison calculation with a set speed. In the motor control device of the image forming apparatus,
The arithmetic control means, the rotational speed detection means, and the motor are operated by the plurality of DC outputs, and at least one DC output is provided with a switching means that is conduction-controlled by the arithmetic control means, and the motor is the switching means. It is arranged in a subsequent stage, and the switching means is made non-conductive when the difference between the speed information from the rotation speed detection means and the target speed becomes a predetermined value or more.

According to a second aspect of the present application, the plurality of DC outputs are generated by a plurality of conversion devices, and at least one of the conversion devices can be controlled to start and stop by the arithmetic control unit. In
The motor is arranged at a subsequent stage of the conversion device that can be controlled by the arithmetic control means, and stops the conversion device when the difference between the speed information from the rotation speed detection means and a target speed becomes a predetermined value or more. It is characterized by being in a state.

  As described above, according to the first invention of the present application, the switching means that has been conventionally used only for reducing the energy consumption of the recording apparatus can be used when the motor rotation speed is abnormal due to a failure of the drive circuit. The load stop operation is also used, so that the number of parts can be reduced, and the cost can be reduced and the mounting space can be secured, so that the apparatus can be downsized. These effects become more conspicuous as the number of drive circuits aimed at improving the function of the recording apparatus increases.

  According to the second invention, in a recording apparatus equipped with a plurality of converters for reducing energy consumption, the load stop operation at the time when the motor rotation speed is abnormal due to a failure of the drive circuit is also used as the start / stop operation of the converter. Thus, even in a recording apparatus that does not have a switching unit, an increase in the number of parts can be suppressed, and cost reduction and mounting space can be secured.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  A first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view for explaining a first embodiment of the present invention, and shows a laser beam printer as an example of an image forming apparatus. The configuration and operation will be described below.

  A laser beam printer main body 101 as an image forming apparatus has a paper feed cassette 102 for setting a recording paper P, and is illustrated from a paper presence / absence sensor 103 and a paper feeding cassette 102 for detecting the presence / absence of the recording paper P in the paper feeding cassette 102. However, the sheet feeding roller 104 for taking out the recording sheet P by the operation of the solenoid, the registration sensor 106 for detecting that the recording sheet P has reached the registration roller 105 downstream of the sheet feeding roller 104, and the recording sheet P aligned by the registration roller 105 are provided. A TOP sensor 107 that detects that the image writing position has been reached is provided. The process cartridge 108 includes a photosensitive drum 109, a primary charging roller 110, a developing device 111, and a cleaner 112 necessary for the electrophotographic system. The polygon mirror 115 is irradiated with laser light from the laser unit 114 in the laser scanner unit 113, and a latent image is formed on the photosensitive drum 109 via the imaging lens 116 and the folding mirror 117. A visible image is formed on the top, and the toner image is transferred onto the recording paper P by the transfer roller 118. A fixing device 119 for heat-fixing the toner image formed on the recording paper P is provided downstream of the transfer roller, and the heater heating element 121 and pressure applied in the polyimide film 120 that rotates together with the recording paper P are provided. The toner image on the recording paper P is fixed on the recording paper P by the roller 122. Further, a paper discharge sensor 123 that detects the paper conveyance state and a paper discharge roller 124 that discharges the recording paper P are provided downstream of the fixing device 119. The fan motor 125 serves to lower the temperature inside the printer main body 101. Although described later, the engine controller 126 is responsible for various operations of the printer. The main motor 127 controls the rotation of the paper feed roller 104, the photosensitive drum 109, the fixing device 119, the paper discharge roller 124, and the like, and performs the operation of transporting the recording paper P. Although not shown, the image controller 128 has a function of binarizing image information from the host computer and transferring processing data to the engine controller 126 and a function of communicating with the host computer.

  FIG. 2 shows an example of a block diagram of a DC voltage system between units in the laser beam printer main body 101 of FIG. 1, in particular, from a converter output. Commercial power is input to the heater control unit and converter via the rectifier filter, and the converter DC output generated from the commercial power source includes a down converter A, a line switch, and a fan that generate DC output for the microcontroller and image controller. A motor is connected. Downstream of the line switch, a laser, a down converter B that generates DC output for various sensors, a polygon mirror motor, a main motor, a high voltage power source, and a paper feed solenoid are connected. The microcontroller makes the line switch non-conductive during standby operation so that power consumption due to the idling current and sensor driving current of the scanner motor, laser driver, and motor driving circuit does not occur. As a result, the laser beam printer 101 is controlled so that the energy consumption during the operation standby (standby) is minimized.

  In addition to the line switch control, the microcontroller performs various controls such as a heater, a high-voltage power supply, various motors, a fan, a solenoid, and a laser in addition to the line switch control, and based on information from each sensor. Various controls for realizing the printing operation are performed. Although not limited to this, a high-voltage power supply, a heater control unit, a motor drive circuit, a fan drive circuit, a converter, downconverters A and B, etc. are arranged on the engine controller 126. In addition, examples of the DC output of each converter include 24V as the output of the converter, 3.3V as the output of the downconverter A, and 5V as the output of the downconverter B. Keep it.

  FIG. 3A clearly shows the relationship among the laser beam printer 101, the drive circuit, the line switch, and the controller. FIG. 3-2 shows a schematic diagram of the rotational speed detection means using a DC brush motor, encoder and optical sensor. The following description will be given by taking an example of a system of these DC brush motor and encoder which is frequently used as an inexpensive system. To do. In FIG. 3A, 301 is a microcontroller, 302 is a line switching element for cutting off a load (in this embodiment, a p-channel MOSFET), 303 is a main motor, 304 is an encoder for detecting the speed of the main motor 303 and an optical device. The rotation speed detection signal output from the sensor is shown. The microcontroller 301 outputs a PWM drive signal 305 for PWM drive of the main motor 303, and each of the limiting resistors 308 is connected to the control terminal of the switching element 307 (n-channel MOSFET in this embodiment) via the push-pull drive stage 306. Connected through. The current outflow terminal of the switching element 307 is connected to the low potential side (GND) of the converter, and the current inflow terminal of the switching element 307 is connected to one end of the main motor 303. The other end of the main motor 303 is connected to the current outflow terminal of the line switch element 302. The current inflow terminal of the line switch element 302 is connected to the high potential side (Vcc) of the converter, and the switching signal 310 is input from the microcontroller 301 via the resistor 309 to the control terminal of the line switch element 302. A resistor 311 is connected between the current inflow terminal of the line switch element 302 and the control terminal for determining the potential. A resistor 312 is connected between the control terminal of the switching element 307 and the current outflow terminal in order to determine the potential of the control terminal of the switching element 307. Between the terminals of the main motor 303, the anode terminal of the motor current regeneration diode 313 is connected to the current inflow terminal side of the switching element 307, and the cathode terminal is connected to the current outflow terminal side of the line switch element 302.

  The microcontroller 301 always counts the time information from the rotation speed detection signal 304, performs a comparison operation with the target rotation speed, and adjusts the power input to the main motor 303 by adjusting the duty of the PWM drive signal 305. To do. The microcontroller 301 decreases the duty of the PWM drive signal 305 when the speed increase is detected from the information from the rotation speed detection signal 304, and increases the duty of the PWM drive signal 305 when the speed decrease is detected. Control input power. In general, the main motor 303 is designed to be able to be driven even when the driving load of the laser beam printer 101 is maximized. In particular, in the case of PWM driving, the main motor 303 in a state where the duty is 100%. Is designed to be larger than the maximum driving load of the laser beam printer 101. On the other hand, when the switching element 307 in which a semiconductor element is generally used is destroyed due to a decrease in impedance between the current inflow terminal and the current outflow terminal due to static electricity, overload, or the like, the overload state of the converter is continued. In addition, an excessive load is applied to various rollers including the photosensitive drum 109 in the process cartridge 108 due to an increase in the rotation speed of the main motor 303. Of course, since the main motor 303 is not rotationally driven at the target rotational speed, a normal image output is not obtained, and the user is bothered by unnecessary paper jams. In this embodiment, in order to avoid the above-described adverse effect due to the increase in the rotation speed of the main motor 303, when the increase in the speed is detected based on the information from the rotation speed detection signal 304, the laser beam printer 101 is in a standby state (standby). A method is proposed in which the power supply to the main motor 303 is cut off by turning off the line switch element 302 arranged to reduce energy consumption.

  In this embodiment, a 1-drum laser beam printer has been described as an example. However, the present application is not limited to the laser beam printer, but can be applied to various recording apparatuses including a copying machine. In this embodiment, a DC brush motor is used as the motor, an optical sensor is used as the sensor, and an encoder is used as the rotation speed detecting means.

  FIG. 4 is for explaining the second embodiment of the present invention. The difference from the first embodiment is that two motors having different functions as a recording device are provided on the current outflow terminal side of the line switch element 302 and The drive circuit is connected. Reference numeral 401 is for expanding the function of the laser beam printer, and an example is a motor for driving an optional cassette. In this embodiment, a DC brush motor which is an inexpensive system will be described as an example. Also, parts having the same functions as those in the first embodiment are denoted by the same reference numerals. Reference numeral 401 denotes an optional motor, and reference numeral 402 denotes a rotational speed detection signal output from the speed detection encoder and optical sensor of the optional motor 401. The microcontroller 301 outputs a PWM drive signal 403 for PWM driving of the option motor 401, and each of the limiting resistors 406 is connected to the control terminal of the switching element 405 (n-channel MOSFET in this embodiment) via the push-pull drive stage 404. Connected through. The current outflow terminal of the switching element 405 is connected to the low potential side (GND) of the converter, and the current inflow terminal of the switching element 405 is connected to one end of the option motor 401. The other end of the option motor 401 is connected to the current outflow terminal of the line switch element 302. A resistor 407 is connected between the control terminal of the switching element 405 and the current outflow terminal in order to determine the potential of the control terminal of the switching element 405. In this embodiment, when the rotation speed detection signal 304 continues to be higher than the target rotation speed, the line switch element 302 is turned off and the rotation speed detection signal 402 of the option motor 401 is set to the target rotation. Even when a state higher than the number continues, a method is proposed in which the line switch element 302 is turned off and the power supply to the main motor 303 and the option motor 401 is cut off.

  In this embodiment, in addition to the main motor 303, an option cassette is proposed as an example of function expansion.

  FIG. 5 is a diagram for explaining a third embodiment of the present invention. The difference from the first and second embodiments is that a plurality of converters for generating DC output are provided, and at least one converter has a micro-circuit. In a system in which start / stop control can be performed from a controller, the operation of the converter to which the motor is supplied with power is stopped when the rotation speed of the motor is increased.

  FIG. 5 shows an example of a block diagram of a DC voltage system between units in a laser beam printer, in particular, a sub-converter and a converter configuration. A commercial converter is input to the heater control unit, converter, and sub-converter via a rectifier filter, and the DC output of the sub-converter generated from the commercial power source includes a down converter A that generates a DC output for a microcontroller and an image controller, A fan motor is connected. Downstream of the converter are a laser, a down converter B that generates DC output for various sensors, a polygon mirror motor, a main motor, a high-voltage power supply, and a paper feed solenoid. The microcontroller stops the converter during the standby operation so that power consumption due to the idling current and sensor driving current of the scanner motor, laser driver, and motor driving circuit does not occur. As a result, the laser beam printer is controlled so that the energy consumption during the operation standby (standby) is minimized.

  Although not shown, the microcontroller always counts the time information from the rotation speed detection signal, performs a comparison operation with the target rotation speed, and if the rotation speed detection signal continues to be higher than the target rotation speed, We propose a method to stop the power supply to the motor by executing the converter stop control and stopping the power supply from the converter.

  In this embodiment, the sub-converter and the converter configuration have been described as examples. However, a case where the circuit configuration is such that the DC output in the converter can be arbitrarily controlled for starting and stopping is also included.

1 is a cross-sectional view of an image forming apparatus for explaining a first embodiment of the present invention. It is a block diagram of 1 converter system for explaining the 1st example of the present invention. (3-1) A circuit diagram around a motor for explaining a first embodiment of the present invention. (3-2) It is the schematic of the motor, encoder, and sensor for demonstrating the 1st Example of this invention. It is a circuit diagram around a motor for explaining a second example of the present invention. It is a block diagram of the 2 converter system | strain for demonstrating the 3rd Example of this invention. The figure for demonstrating a prior art example simply.

Explanation of symbols

301 Microcontroller 302 Line switch for cutting off load 304 Rotation speed detection signal 307 Switching element 310 Switching signal

Claims (3)

A plurality of DC outputs, a motor for driving the apparatus load, a rotational speed detection means for detecting the rotational speed of the motor, and speed information from the rotational speed detection means are counted and compared with a target speed. In order to rotate the motor at a constant speed, in the motor control device of the image forming apparatus configured with an arithmetic control unit that controls a power input control unit that controls power input to the motor,
The arithmetic control means, the rotational speed detection means, and the motor are operated by the plurality of DC outputs, and at least one DC output is provided with a switching means that is conduction-controlled by the arithmetic control means, and the motor is the switching means. Placed in the latter stage,
A motor control device for an image forming apparatus, wherein the switching means is made non-conductive when a difference between speed information from the rotation speed detection means and a target speed becomes a predetermined value or more. In the motor control device of the image forming apparatus in which the plurality of DC outputs are generated by a plurality of conversion devices, and at least one of the conversion devices can be controlled to start and stop from the arithmetic control unit.
The arithmetic control means, the rotational speed detection means, and the motor are operated by the plurality of DC outputs, and the motor is arranged at a subsequent stage of the conversion device that can be controlled from the arithmetic control means,
2. The motor control of the image forming apparatus according to claim 1, wherein when the difference between the speed information from the rotation speed detection unit and a target speed becomes a predetermined value or more, the conversion device is stopped. apparatus.   The input power control means is input power control means by PWM control means using a semiconductor element, the rotation speed detection means is encoder means for converting the rotation speed into an electric signal, and the motor is a DC brush motor. The motor control device for an image forming apparatus according to claim 1, wherein:

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