JP5509670B2 - Image forming apparatus, image forming apparatus control method, and image forming apparatus control program - Google Patents

Description

  The present invention relates to an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program, and more particularly to an image forming apparatus having a fan for causing air inside the apparatus to flow, an image forming apparatus control method, and an image The present invention relates to a control program for a forming apparatus.

  Image forming apparatus (scan function, facsimile function, copy function, printer function, data communication function, and server function MFP (Multi Function Peripheral), facsimile apparatus, copier, In a printer or the like, a motor that generates a driving force used for image formation is used. Examples of such a motor include a motor that drives a roller that conveys a sheet and a motor that drives a print engine unit.

  Such an image forming apparatus is provided with a fan for allowing the air in the apparatus to flow. The fan is provided, for example, to prevent the temperature in the apparatus from increasing due to an image forming operation or the like. The fan cools the device by, for example, sucking or exhausting air in the device and exchanging it with outside air.

  Patent Document 1 discloses an X-ray computed tomography apparatus in which regenerative energy generated during motor deceleration is stored in a capacitor and a cooling fan is driven using the stored regenerative energy. This imaging device reduces the amount of regenerative energy to be radiated in the regenerative resistor by driving the cooling fan to consume regenerative energy. This imaging apparatus switches between storing power to a condenser of regenerative energy and supplying regenerative energy to a cooling motor with a switch. In addition, the portion of the regenerative energy that exceeds the amount of electricity stored in the capacitor is consumed as heat by the regenerative resistor. Whether the capacitor is charged or passed through a regenerative resistor can be switched by a switch.

  Patent Document 2 listed below discloses an image forming apparatus that charges a secondary battery by back electromotive force or regenerative power of an actuator such as a motor. The image forming apparatus operates a secondary battery as an auxiliary power source at the time of starting the motor or the like, and reduces the burden on the AC power line. The image forming apparatus can efficiently charge the secondary battery using regenerative power or the like.

JP 2006-289066 A JP 2007-178039 A

  By the way, when the power supply to the image forming apparatus is interrupted during image formation, the fan stops. In this case, various problems may occur.

  For example, when the cooling fan as described above stops and heat remains in the apparatus, the temperature in the apparatus becomes high. When the temperature inside the apparatus becomes high, the rate of occurrence of breakage or failure of components in the apparatus increases. On the other hand, when selecting parts so that damage does not occur even if the temperature in the apparatus rises, the cost of the parts of the image forming apparatus increases.

  In particular, in an electrophotographic image forming apparatus that performs corona discharge in a charging process, an ozone fan is provided for collecting or discharging ozone generated in the charging process from the apparatus. In such an image forming apparatus, when the power supply is interrupted during image formation, the ozone fan stops and ozone stays in the vicinity of the photoreceptor. Then, the photoconductor is deteriorated by ozone, and image formation defects such as ozone unevenness occur.

  The direct solution regarding the said problem is not disclosed by patent document 1 and patent document 2. FIG. Further, for the above problem, for example, as disclosed in Patent Document 1 and Patent Document 2, it is conceivable to provide a capacitor or a battery and drive the fan using energy stored in the capacitor or the like. . However, providing a capacitor and a battery increases the size of the image forming apparatus, increases the number of parts, and increases the manufacturing cost. In this case, a large number of switches and the like are required for switching the path for charging and discharging the capacitor and the like. This complicates the control of electrical circuits and switches inside the apparatus, and increases the manufacturing cost of the image forming apparatus.

  The present invention has been made to solve such a problem, and even if power supply is stopped during printing, the air in the apparatus can be made to flow thereafter, and the image forming apparatus can be manufactured at low cost. It is an object of the present invention to provide an image forming apparatus control method and an image forming apparatus control program.

In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus includes at least one motor driven during an image forming operation by power supplied from a power source, and a fan for causing air inside the apparatus to flow. , Power supply means for supplying power supplied from the power source to the fan, regenerative means for taking out the regenerative power generated until the motor stops, and regenerative power extracted from the motor by the regenerative means to the fan Regenerative power supply means, selection means for selecting power supply to the fan by the power supply power supply means and power supply to the fan by the regenerative power supply means, and supply of power from the power supply during the image forming operation. Fan control means for performing control to continue driving of the fan when shut off, and the fan control means is a power source during the image forming operation. When the supply of al the power is cut off, to drive the fan in a different operating mode than when the power from the power source is supplied, regeneration means, the supply of power from the power source during the image forming operation is interrupted When the power is supplied from the power source, the selection unit supplies power to the fan by the power source power supply unit, and the power from the power source is supplied during the image forming operation. When the supply is cut off, the regenerative power supply means supplies power to the fan, and the regenerative means obtains a large regenerative power by applying a strong braking force immediately after the motor starts decelerating. together, over time, Ru weak to change the braking force.

  Preferably, the selection means performs selection according to the magnitude of power that can be supplied to the fan by the power supply power supply means and the magnitude of power that can be supplied to the fan by the regenerative power supply means.

Preferably, the fan control unit drives the fan so that the rotation speed is lower when the supply of power from the power source is interrupted during the image forming operation than when the power from the power source is supplied.

According to another aspect of the present invention, at least one motor driven during an image forming operation by power supplied from a power source, a fan for causing air inside the apparatus to flow, and power supplied from the power source to the fan. A control method of an image forming apparatus including a power supply unit for supplying power includes a regenerative step for extracting regenerative power generated before the motor stops from the motor, and supplying regenerative power extracted from the motor by the regenerative step to a fan. Regenerative power supply step, selection step for selecting power supply to the fan by the power source power supply means and power supply to the fan by the regenerative power supply step, and supply of power from the power source during the image forming operation is cut off A fan control step for performing control to continue driving of the fan when the When the supply of power from the power source during the image forming operation is interrupted, to drive the fan in a different operating mode than when the power from the power source is supplied, regeneration step, from the power source during the image forming operation When the power supply is cut off, the motor is decelerated to extract the regenerative power.When power is supplied from the power supply, the power supply power supply step supplies power to the fan during the image forming operation. When the supply of power from the power source is interrupted, the regenerative power supply step supplies power to the fan.In the regenerative step, a strong braking force is applied immediately after the motor starts decelerating. together to obtain a large regenerative power Te, over time, Ru weak to change the braking force.

According to still another aspect of the present invention, at least one motor driven during an image forming operation by power supplied from a power source, a fan for causing air inside the apparatus to flow, and power supplied from the power source as a fan A control program for an image forming apparatus including a power supply unit for supplying power to a regenerative step for extracting regenerative power generated before the motor stops from the motor, and supplying regenerative power extracted from the motor by the regenerative step to the fan A regenerative power supply step, a selection step for selecting power supply to the fan by the power source power supply means and a power supply to the fan by the regenerative power supply step, and power supply from the power source during the image forming operation. A fan control step for controlling the fan to continue to drive when shut off. Is the row, the fan control step, when the supply of power from the power source during the image forming operation is interrupted, to drive the fan in a different operating mode than when the power from the power source is supplied, regeneration step, When power supply from the power supply is interrupted during image forming operation, the motor is decelerated and the regenerative power is taken out, and the selection step uses the power supply power supply step to supply power to the fan when power is supplied from the power supply. When power supply from the power source is interrupted during image forming operation, power is supplied to the fan by the regenerative power supply step, and the regenerative step is performed immediately after the motor starts decelerating. strong as the braking force acts to with obtaining large regenerative power, over time, Ru weak to change the braking force.

  According to these inventions, when the power supply to the image forming apparatus is interrupted, the fan can be continuously driven using the regenerative power. Accordingly, there is provided an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of causing air in the apparatus to flow after power supply is stopped during printing and having a low manufacturing cost. be able to.

1 is a side view illustrating a hardware configuration of an image forming apparatus according to one embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus. FIG. 2 is a block diagram illustrating a circuit configuration of a drive system of an image forming apparatus centering on a power supply unit and a drive unit. It is a block diagram which shows the drive circuit of a motor. 3 is a flowchart illustrating an operation flow of the image forming apparatus. It is a graph which shows an example of the deceleration curve of the motor under regenerative brake mode. It is a graph which shows an example of the change of the rotational speed of the fan motor of the fan under regenerative brake mode.

  Hereinafter, an image forming apparatus according to one embodiment of the present invention will be described.

  [Embodiment]

  The image forming apparatus has a print function of printing (printing) on a sheet by using an electrophotographic method while the sheet is conveyed by, for example, a roller.

  FIG. 1 is a side view showing a hardware configuration of an image forming apparatus 1 according to one embodiment of the present invention.

  Referring to the figure, the image forming apparatus 1 includes a paper feed cassette 3, a paper discharge tray 5, a printing unit 30, and a fan 40.

  The paper feed cassette 3 is disposed in the lower part of the image forming apparatus 1 so as to be detachable from the housing of the image forming apparatus 1. The paper loaded in each paper feed cassette 3 is fed one by one from the paper feed cassette 3 and sent to the printing unit 30 at the time of printing. The number of paper feed cassettes 3 is not limited to one, and may be larger than that.

  The paper discharge tray 5 is disposed above the housing of the image forming apparatus 1. A sheet on which an image is formed by the printing unit 30 is discharged from the inside of the housing to the discharge tray 5.

  The print unit 30 is disposed inside the housing of the image forming apparatus 1. The printing unit 30 roughly includes a paper transport unit 200, a toner image forming unit 300, a fixing device 400, and a driving unit (shown in FIG. 2) 500. The print unit 30 is configured to be able to form a color image on a sheet by synthesizing four color images of CMYK by a so-called tandem method.

  The paper transport unit 200 includes a paper feed roller 210, a transport roller 220, a paper discharge roller 230, and the like. The paper feed roller 210, the transport roller 220, and the paper discharge roller 230 each transport the paper by rotating the rollers while sandwiching the paper between two opposing rollers, for example. The paper feed roller 210 feeds paper one by one from the paper feed cassette 3. The paper is fed into the housing of the image forming apparatus 1 by the paper feed roller 210. The transport roller 220 transports the paper fed by the paper feed roller 210 to the toner image forming unit 300. Further, the conveyance roller 220 conveys the sheet that has passed through the fixing device 400 to the paper discharge roller 230. The paper discharge roller 230 discharges the paper transported by the transport roller 220 to the outside of the casing of the image forming apparatus 1. In addition, the paper transport unit 200 may include a roller used for transporting paper other than these.

  The toner image forming unit 300 includes four color toner bottles 301Y, 301M, 301C, and 301K (hereinafter, collectively referred to as a toner bottle 301), an intermediate transfer belt 305, a transfer roller 307, and four sets. Development units 310Y, 310M, 310C, and 310K (hereinafter, these may be collectively referred to as development unit 310), a laser scan unit 320, and the like.

  The yellow toner bottle 301Y, the magenta toner bottle 301M, the cyan toner bottle 301C, and the black toner bottle 301K store CMYK toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively. To do.

  The intermediate transfer belt 305 has an annular shape and is stretched between two rollers (not shown). The intermediate transfer belt 305 rotates in conjunction with the paper transport unit 200. The transfer roller 307 is disposed so as to face a portion of the intermediate transfer belt 305 that is in contact with one roller. The distance between the transfer roller 307 and the intermediate transfer belt 305 is adjusted by a pressure contact / separation mechanism. The sheet is conveyed while being sandwiched between the intermediate transfer belt 305 and the transfer roller 307.

  The developing unit 310 includes a photosensitive drum 311, a developing device, a cleaner, a charger, and the like. Here, the photosensitive drums 311 are photosensitive drums 311Y, 311M, 311C, and 311K corresponding to the developing units 310Y, 310M, 310C, and 310K, respectively. The yellow developing unit 310Y, the magenta developing unit 310M, the cyan developing unit 310C, and the black developing unit 310K are arranged to form Y, M, C, and K images, respectively. The developing unit 310 is juxtaposed directly below the intermediate transfer belt 305. The laser scan unit 320 is disposed on each photosensitive drum 311 so as to be able to scan with laser light.

  In the toner image forming unit 300, the laser scanning unit 320 forms a latent image on the photosensitive drum 311 that is uniformly charged by the charger based on the image data for each color of YMCK. The developing device forms a toner image for each color on each photosensitive drum 311. Each photosensitive drum 311 transfers the toner image to the intermediate transfer belt 305, and forms a mirror image of the toner image formed on the paper on the intermediate transfer belt 305 (primary transfer). Thereafter, the transfer roller 307 to which a high voltage is applied transfers the toner image formed on the intermediate transfer belt 305 to the sheet, and a toner image is formed on the sheet (secondary transfer).

  When the toner in the developing unit 310 decreases due to image formation, the toner stored in the toner bottle 301 of each color is supplied to the developing unit, and image formation can be continuously performed.

  The fixing device 400 includes a heating roller 401 and a pressure roller 403. The fixing device 400 conveys the sheet on which the toner image is formed between the heating roller 401 and the pressure roller 403 and heats and presses the sheet. As a result, the fixing device 400 melts the toner adhering to the paper and fixes it on the paper to form an image on the paper. The sheet that has passed through the fixing device 400 is discharged from the casing of the image forming apparatus 1 to the discharge tray 5 by the discharge roller 230.

  The drive unit 500 includes, for example, a main motor (an example of a motor) 501, a fixing motor (an example of a motor) 502, a black developing motor (an example of a motor) 503, a color developing motor (an example of a motor) 504, and a color photoconductor motor. (An example of a motor) 505 (hereinafter, these motors may be simply referred to as motors 501 to 505). The drive unit 500 is driven under the control of the CPU 21 described later. The main motor 501 carries the paper from the paper feeding process to the transfer process and drives the intermediate transfer belt 305 and the black photosensitive drum 311K. The fixing motor 502 drives the fixing device 400. The black developing motor 503 drives the black developing unit 310K. A color developing motor 504 drives yellow, magenta, and cyan developing units 310Y, 310M, and 310C. The color photoconductor motor 505 drives the yellow, magenta, and cyan photoconductor drums 311Y, 311M, and 311C. In addition to these motors 501 to 505, for example, a pressure contact / separation motor for changing the pressure of the transfer roller 307 or the fixing device 400 to sandwich the paper may be provided.

  The fan 40 is for cooling the image forming apparatus 1. The fan 40 has a fan motor (not shown). The fan 40 is rotated by driving a fan motor under the control of the CPU 21. By rotating, the fan 40 introduces outside air into the housing of the image forming apparatus 1 and causes the air inside the housing to flow. When outside air is introduced by the fan 40, for example, air is exhausted from the inside of the housing through an exhaust port provided in the upper portion of the housing. By driving the fan 40 in this way, the air inside the housing is replaced, and the image forming apparatus 1 is cooled. Note that the fan 40 may be arranged to rotate to discharge the air inside the housing to the outside, thereby causing the air inside the housing to flow.

  FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus 1.

  Referring to the figure, image forming apparatus 1 further includes an operation unit 11, a control device 20, a nonvolatile memory 27, an interface unit 29, and a power supply unit (an example of power supply means) 600. Yes. The control device 20 and the non-volatile memory 27 constitute a control unit (shown in FIG. 3) 15.

  The operation unit 11 is disposed in the casing of the image forming apparatus 1 so that it can be operated by a user. A display panel 13 is disposed on the operation unit 11. The display panel 13 is, for example, an LCD (Liquid Crystal Display) provided with a touch panel. The display panel 13 displays a guidance screen for the user or displays an operation button to accept a touch operation from the user. The display panel 13 performs display under the control of the CPU 21 of the control device 20. When the user operates the display panel 13, operation buttons (not shown), or the like, the operation unit 11 transmits an operation signal or a predetermined command corresponding to the operation to the CPU 21. That is, the user can cause the image forming apparatus 1 to execute various operations by operating the operation unit 11.

  The control device 20 includes a CPU 21, a ROM (Read Only Memory) 23, a RAM (Random Access Memory) 25, and the like. The control device 20 is connected to the system bus together with the operation unit 11, the nonvolatile memory 27, the interface unit 29, the power supply unit 600, and the like. Thereby, the control device 20 and each part of the image forming apparatus 1 are connected so that signals can be transmitted and received.

  The CPU 21 controls various operations of the image forming apparatus 1 by executing a control program 27 a and the like stored in the nonvolatile memory 27. For example, the control program may be stored in the ROM 23 or the like. When an operation signal is transmitted from the operation unit 11 or an operation command is transmitted from a client PC or the like, the CPU 21 executes a predetermined control program 27a in response to the operation signal. Accordingly, a predetermined operation of the image forming apparatus 1 is performed in accordance with the operation of the operation unit 11 by the user.

  The ROM 23 is, for example, a flash ROM (Flash Memory). The ROM 23 stores data used for operating the image forming apparatus 1 and function setting data of the image forming apparatus 1. The CPU 21 reads data from the ROM 23 and writes data to the ROM 23 by performing predetermined processing. The ROM 23 may be non-rewritable.

  The RAM 25 is a main memory of the CPU 21. The RAM 25 is used to store data necessary when the CPU 21 executes the control program 27a as will be described later.

  The nonvolatile memory 27 is, for example, an EEPROM (Electrically Erasable and Programmable Read Only Memory) or a flash ROM. The non-volatile memory 27 stores a control program (program) 27 a for performing various operations of the image forming apparatus 1. The nonvolatile memory 27 stores, for example, job (JOB) data sent from the outside via the interface unit 29. The nonvolatile memory 27 can store a plurality of jobs transmitted from one client PC or a plurality of client PCs. The nonvolatile memory 27 backs up information that needs to be maintained even after the image forming apparatus 1 is powered off. The nonvolatile memory 27 stores operation information of the image forming apparatus 1 such as the total number of printed sheets and the driving time of the photosensitive drum 311. These pieces of information are written and read by the CPU 21. Note that the nonvolatile memory 27 may be configured to store setting information of the image forming apparatus 1 and the like. The nonvolatile memory 27 may be, for example, an HDD (Hard Disk Drive).

  The interface unit 29 is configured, for example, by combining a hardware unit such as a NIC (Network Interface Card) and a software unit that performs communication using a predetermined communication protocol. The interface unit 29 connects the image forming apparatus 1 to an external network such as a LAN. As a result, the image forming apparatus 1 can communicate with an external apparatus such as a client PC connected to the external network. The image forming apparatus 1 can receive a job from a client PC. Further, the image forming apparatus 1 can transmit the image data to the client PC or by E-mail via a mail server or the like. Note that the interface unit 29 may be configured to be connectable to an external network by wireless communication. The interface unit 29 may be, for example, a USB (Universal Serial Bus) interface. In this case, the interface unit 29 enables communication between the external device connected via the communication cable and the image forming apparatus 1.

  The power supply unit 600 is provided inside the housing of the image forming apparatus 1. The power supply unit 600 is connected to a commercial power supply and supplies power to each unit of the apparatus based on the commercial power supply.

  Here, in the present embodiment, the development units 310Y, 310M, 310C, and 310K are provided with nonvolatile memories 319Y, 319M, 319C, and 319K, respectively. The toner bottles 301Y, 301M, 301C, and 301K are provided with nonvolatile memories 309Y, 309M, 309C, and 309K, respectively. The nonvolatile memories 319Y to 319K and 309Y to 309K are, for example, CSIC (Customer Specific Integrated Circuit), and the CPU 21 can read and write information. The CPU 21 writes life information corresponding to the life state of each consumable item in the nonvolatile memories 319Y to 319K and 309Y to 309K. The CPU 21 can appropriately manage the lifetime of each consumable according to the lifetime information.

  FIG. 3 is a block diagram illustrating a circuit configuration of a drive system of the image forming apparatus 1 with the power supply unit 600 and the drive unit 500 as the center.

  The power source unit (low voltage power source unit) 600 is driven by being supplied with commercial power through a power plug 601. The power supply unit 600 includes a main power switch 603, a rectification unit 605, a first DC-DC converter 607, a diode 609, a maximum value selection unit (an example of a selection unit) 611, and a second DC-DC converter. 615. The main power switch 603 switches energization / cutoff of the input of the AC power supply.

  The rectifier 605 converts alternating current input from a commercial power source into direct current. The first DC-DC converter 607 converts a direct current voltage into a stable low voltage direct current. In the present embodiment, the first DC-DC converter 607 outputs a DC voltage of 24V. The first DC-DC converter 607 outputs a DC voltage to the drive unit 500 via the diode 609. Further, the first DC-DC converter 607 outputs a DC voltage to the maximum value selection unit 611. The diode 609 is arranged so that the current does not flow to the first DC-DC converter 607 when regenerative power is generated in the drive unit 500 as described later. This prevents the first DC-DC converter 607 from being damaged.

  In the drive unit 500, the motors 501 to 505 are driven under control instructions from the CPU 21, respectively. The motors 501 to 505 are driven by being supplied with the 24V DC voltage output from the first DC-DC converter 607.

  The maximum value selection unit 611 includes two diodes 611a and 611b. The diode 611a is inserted into the connection path between the first DC-DC converter 607 and the first DC-DC converter 607 side as an anode. The diode 611b is inserted into a connection path between the diode 609 and the drive unit 500 so that the drive unit 500 side becomes an anode. The two diodes 611a and 611b are arranged in parallel with the cathode side connected.

  The maximum value selection unit 611 outputs the DC voltage on the higher voltage side of the two diodes 611 a and 611 b to the second DC-DC converter 615 and the fan 40. As a result, as described later, a relatively high voltage is more stably supplied to the second DC-DC converter 615 and the fan 40 even when power supply to the motors 501 to 505 is interrupted. Therefore, the power supply to the fan 40 and the power supply from the second DC-DC converter 615 to the control device 20 are more stable. In addition, by providing the diodes 611a and 611b, the backflow of current from the higher voltage side to the lower voltage side of the diodes 611a and 611b is prevented. A smoothing circuit or the like may be provided between the maximum value selection unit 611 and the second DC-DC converter 615.

  The fan 40 is driven by the electric power supplied via the maximum value selection unit 611 under the control instruction from the CPU 21.

  The second DC-DC converter 615 converts the input DC voltage into a stable low-voltage current. In the present embodiment, the second DC-DC converter 615 outputs a 3.3V DC voltage to the control device 20 as a signal system power supply. Note that the second DC-DC converter 615 may be configured to output, for example, a DC voltage of 5V.

  The control device 20 operates by being supplied with a 3.3V DC voltage from the second DC-DC converter 615. In the control device 20, the CPU 21 communicates with the ROM 23 and the like to read a control program and write data, thereby controlling the image forming apparatus 1. The CPU 21 communicates with the nonvolatile memory 27.

  In the present embodiment, the CPU 21 monitors the output voltage from the first DC-DC converter 607, that is, monitors the presence or absence of power supply. The power supply state is monitored, for example, by dividing the output voltage from the first DC-DC converter 607 with a resistor and the CPU 21 detecting the voltage. Thereby, the CPU 21 can detect that commercial power is not supplied due to a power failure or the like, or that the main power switch 603 is turned off and the power supply is cut off. The CPU 21 may monitor the power supply state by any other detection method.

  FIG. 4 is a block diagram showing a drive circuit for the motor 501.

  Hereinafter, the drive circuit of the motor 501 will be described with reference to the drawings. The configuration of the drive circuits of the other motors 502 to 505 is the same as that of the motor 501.

  The motor 501 is a DC motor. The motor 501 includes an energization control unit 511, a drive circuit unit 513, and a winding 515. The power supply unit 600 supplies a DC voltage to the motor 501. The DC voltage from the power supply unit 600 is applied to the energization control unit 511 and the drive circuit unit 513. The CPU 21 of the control device 20 outputs a control instruction such as a speed command to the energization control unit 511. The energization control unit 511 in the motor 501 operates the drive circuit unit 513 in response to an instruction to drive the motor 501 by a control instruction. The drive circuit unit 513 generates power of the motor 501 by supplying the power supplied from the power supply unit 600 to the winding 515. When the stop of the motor 501 is instructed, the energization control unit 511 stops the supply of power from the drive circuit unit 513 to the winding 515 and stops the motor 501.

  In the present embodiment, the motor 501 is configured to be capable of braking by regenerative braking as a braking mode (braking method). Regenerative braking is performed when the CPU 21 sets the regenerative braking mode as a braking mode. When the regenerative brake mode is set and the CPU 21 issues a deceleration instruction, the energization control unit 511 operates the drive circuit unit 513 to perform regenerative braking of the motor 501. When the regenerative braking is performed, the kinetic energy of the motor 501 and the member moving with the rotation thereof is converted into electric energy (regenerative power) by the winding 515. The generated regenerative power is supplied from the drive circuit unit 513 to the power supply unit 600. Note that the supply of driving power and the supply of regenerative power between the power supply unit 600 and the motor 501 may be performed with a common electric wire, or may be performed with dedicated electric wires.

  The regenerative power generated by the motor 501 or the like is input to the maximum value selection unit 611. The regenerative power input to the maximum value selection unit 611 is compared with the power input from the first DC-DC converter 607 to the maximum value selection unit 611, and if it is larger, the regenerative power is output from the maximum value selection unit 611.

  The regenerative power output from the maximum value selection unit is supplied to the fan 40 and the control unit 15 through two routes. In the first route, the regenerative power is supplied from the maximum value selection unit 611 to the fan 40 as it is. Thereby, the fan 40 can be driven while the regenerative power is supplied. In the second route, the regenerative power is input from the maximum value selection unit 611 to the second DC-DC converter 615. The second DC-DC converter 615 supplies 3.3V DC regenerative power to the control unit 15 using the input power. The regenerative power is supplied to the control unit 15 for a while after the power is shut off. Thereby, while the predetermined regenerative power is supplied to the control unit 15, the control device 20 and the nonvolatile memory 27 are driven by the regenerative power.

  The motor 501 is configured to be able to use a so-called short brake braking method or a so-called free-run braking method (stop method) as another braking mode. These braking modes are executed by controlling the drive circuit unit 513 when a deceleration instruction is issued when the short brake mode or the free-run mode is set by the CPU 21. Here, the free-run mode simply means turning off the power supply to the motor 501 so that the motor 501 stops naturally. The short brake mode is a closed circuit having only the motor 501 and the power supply to the motor 501 is turned off. The motor 501 rotating by inertia generates a counter electromotive force in the closed circuit. It means that the motor 501 is braked as a resistance. The CPU 21 is configured to be able to select a braking mode according to the situation. Thereby, the motor 501 and the like can be braked in accordance with the operation status of the image forming apparatus 1.

  As the braking control of the motor 501 during the normal image forming operation, any of stop control in free run, stop control in the short brake mode, and stop control in the regenerative brake mode may be employed. The motor can be quickly stopped by the regenerative brake mode or the short brake mode, or the motor can be kept in an operating state longer than usual by the free run mode. The motor 501 may be configured to be brakeable by another braking method such as a reverse brake mode in which a current in the reverse direction is forced to flow.

  In the present embodiment, when the power supply to the image forming apparatus 1 is interrupted during the image forming operation, the CPU 21 causes the motors 501 to 505 to regeneratively brake and continuously operate the fan 40 using the regenerated electric energy. Let Hereinafter, this operation will be described.

  FIG. 5 is a flowchart showing an operation flow of the image forming apparatus 1.

  When the main power switch 603 is on, power is supplied from the commercial power source to the power supply unit 600, and power is supplied to the image forming apparatus 1, the CPU 21 performs control as described below.

  In step S <b> 101, the CPU 21 monitors whether the image forming apparatus 1 is supplied with power. This monitoring is performed by detecting the output voltage of the first DC-DC converter 607 as described above.

  In step S <b> 103, the CPU 21 determines whether power is supplied to the image forming apparatus 1. That is, the CPU 21 determines whether or not power supply to the motors 501 to 505 is not performed. When there is power supply, that is, when the main power supply is not turned off, the CPU 21 continues to monitor the presence or absence of power supply in step S101.

  When it is detected in step S103 that there is no power supply, in step S105, the CPU 21 selects regenerative braking of the motors 501 to 505. The CPU 21 sets the regenerative braking mode as the braking mode of the motors 501 to 505 and instructs the energization control unit 511 to decelerate and stop. Thus, the motors 501 to 505 convert the accumulated kinetic energy into electric power by regenerative braking, and output regenerative electric power.

  In step S <b> 107, the CPU 21 supplies regenerative power generated by the motors 501 to 505 to the fan 40. That is, as a result of the regenerative braking performed by the CPU 21, when the voltage of the regenerative power becomes higher than the output voltage of the first DC-DC converter 607, the regenerative power selected by the maximum value selection unit 611 is changed to the maximum value selection unit 611. Is output from. As a result, regenerative power is supplied to the fan 40. Further, the CPU 21 can operate continuously. At this time, the CPU 21 continues the control for driving the fan 40 from the time when the power is supplied. The fan 40 is rotated by a fan motor driven by regenerative power under the control of the CPU 21. Thereby, even if the power supply of the image forming apparatus 1 is interrupted during the image forming operation, the fan 40 continues to rotate.

  At this time, the CPU 21 may operate the fan 40 in the same manner as when power is supplied, or is different from when power is supplied, such as operating at a relatively low rotational speed. The operation may be performed in the operation mode. For example, by operating at a low rotational speed, it is possible to reduce the strength of regenerative braking and increase the time until the speed of the motors 501 to 505 becomes zero, thereby driving the fan 40 for a long time.

  FIG. 6 is a graph showing an example of a deceleration curve of the motors 501 to 505 under the regenerative braking mode.

  Referring to the figure, motors 501 to 505 are rotating at a constant rotational speed during the image forming operation. Time t0 is when the power supply to the motors 501 to 505 is cut off, for example, because the main power switch 603 is turned off. At this time, the direct current voltage for motor feeding output from the first DC-DC converter 607 starts to drop from 24V. Further, the CPU 21 detects that the motors 501 to 505 are not supplied with power, and regeneratively brakes the rotating motors 501 to 505. Regenerative braking is performed by the control of the CPU 21 so that the rotational speeds of the motors 501 to 505 are decelerated at a substantially constant acceleration. Thereby, after the deceleration is started at time t0, the rotational speed of the motors 501 to 505 decreases substantially in proportion to the passage of time, and the motors 501 to 505 stop at time t1.

  The deceleration curves of the motors 501 to 505 are preferably those that can obtain a large amount of regenerative power as described above. However, the present invention is not limited to this, and the CPU 21 may perform braking using any deceleration curve. For example, the CPU 21 may obtain a large regenerative electric power so that a stronger braking force works during a period immediately after the start of braking, and the braking force may become weaker as time passes.

  FIG. 7 is a graph showing an example of the rotational speed of the fan motor of the fan 40 under the regenerative braking mode.

  Referring to the figure, times t0 and t1 correspond to the times shown in FIG. The fan motor is controlled to be turned on / off by the CPU 21, for example, and operates at a rotation speed corresponding to the supplied voltage during the operation.

  During the image forming operation, the fan motor is rotated at a substantially constant rotational speed by being supplied with the output voltage from the first DC-DC converter 607 derived from the commercial power supply (drive power supply). . When the power supply is cut off at time t0, the fan motor operates with regenerative power. At this time, regenerative power is supplied, the voltage rises, and the rotation speed rises. Thereby, since the flow volume of the fan 40 increases temporarily, the heat which accumulates in an apparatus can be discharged | emitted rapidly. Thereafter, as the regenerative power voltage decreases, the rotational speed decreases. When the motors 501 to 505 are stopped at time t1, the regenerative power is not supplied, and the rotational speed of the fan motor is also zero.

  [Effects of the embodiment]

  In the image forming apparatus configured as described above, when the power is cut off during printing, the CPU regeneratively brakes the motor and rotates the fan using the regenerated electric power. Therefore, even after the power supply is shut off, the air in the apparatus can be exchanged with the outside air and the temperature of the image forming apparatus can be prevented from rising. Thereby, the failure of the image forming apparatus can be reduced. In addition, this makes it possible to use inexpensive parts that do not have particularly high heat resistance, and to reduce the manufacturing cost of the image forming apparatus.

  In such an image forming apparatus, the fan can be driven when the power is shut off without providing a battery or a switch for switching the power feeding path. Therefore, the image forming apparatus can be reduced in size. In addition, the circuit configuration can be simplified and the manufacturing cost can be reduced.

  Further, since the regenerative power is not stored and supplied to the fan as it is, it can be continuously driven without stopping the fan motor. Therefore, by supplying regenerative electric power, the fan can be accelerated, strong wind can be blown, and heat accumulated in the apparatus can be quickly discharged.

  Note that the CPU, for example, when it is clear that the temperature in the image forming apparatus has not increased so much, such as when the power is turned off shortly after the image forming operation is started, for example, the short brake mode or the free run mode. For example, the motor may be controlled in another braking mode.

  [Others]

  The CPU may be configured to execute regenerative braking only with a specific motor and supply the regenerative power to the specific motor.

  Further, instead of the maximum value selection unit, a switch for switching the power supply path to the fan of the power output from the first DC-DC converter and the regenerative power is provided. Or the like. Thereby, the power supply to a fan etc. can be controlled more finely.

  Further, the fan is not limited to a cooling fan. For example, when the image forming apparatus is provided with an ozone fan for collecting or discharging the generated ozone, the ozone fan may be driven by regenerative power as described above. As a result, the manufacturing cost of the image forming apparatus can be reduced and the occurrence of image formation defects such as ozone unevenness can be reliably prevented. In this case, the ozone fan and the cooling fan may be driven with regenerative power, or only one of them may be driven with regenerative power.

  Also, the number of fans may be plural. In this case, when the power supply is shut off, all the fans may be driven by regenerative power, or only a predetermined fan may be driven by regenerative power. Further, a CPU that is driven by regenerative power may be appropriately selected and driven by the CPU according to the state of the image forming apparatus.

  Further, the image forming apparatus is not a so-called tandem type as described above, and performs image formation using a smaller number of photoconductors than the number of developing units while rotating the developing rack unit on which the developing units are mounted. It may be a cycle machine. In this case, when the power is shut off, regenerative braking can be performed on a motor including a rack drive motor that drives the developing rack unit in the same manner as in the above-described embodiment. Since the developing rack unit is large and heavy, the rack driving motor and the developing rack unit have large kinetic energy when driven. Therefore, when the rack drive motor is driven when the power supply to the image forming apparatus is interrupted, the CPU can obtain a large amount of regenerative power from the rack drive motor. Thus, the CPU may be able to generate a larger amount of regenerative power for a long time by performing regenerative braking with a motor that is interlocked with a large-sized member that has a large kinetic energy during operation. As a result, the fan can be driven for a longer time, and a larger amount of air can be blown.

  The fan is not limited to when the power is shut off, and the fan may be driven by regenerative braking of the motor when the image forming apparatus shifts to a stopped state for other reasons. For example, when a jam (JAM) occurs in the paper transport unit or a temperature error occurs in the fixing device, regenerative braking can be performed to rotate the fan. Thereby, energy can be used effectively and power consumption can be reduced.

  The image forming apparatus may be a monochrome / color copying machine, a printer, a facsimile machine, or the like. Further, the image forming apparatus is not limited to an electrophotographic system, and may be, for example, an ink jet printer. The image forming apparatus may be an MFP (Multi Function Peripheral) having a scanner function, a copying function, a printer function, a facsimile function, a data communication function, and a server function. In the scanner function, an image of a set original is read and stored in an HDD or the like. In the copying function, it is further printed (printed) on paper or the like. In the function as a printer, when a print instruction is received from an external terminal such as a PC, printing is performed on a sheet based on the instruction. In the facsimile function, facsimile data is received from an external facsimile machine or the like and stored in an HDD or the like. In the data communication function, data is transmitted / received to / from a connected external device. In the server function, a plurality of users can share data stored in the HDD or the like.

  Further, the processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet. The processing described in the text in the above flowchart is executed by the CPU according to the program.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Control device 21 CPU
27 Nonvolatile memory 30 Print unit 40 Fan 300 Toner image forming unit 501 Main motor (an example of motor)
502 Fixing motor (an example of a motor)
503 Black development motor (example of motor)
504 Color development motor (an example of a motor)
505 Color photoreceptor motor (an example of a motor)
600 Power supply unit (an example of power supply means)
611 Maximum value selection unit (an example of selection means)

Claims (5)

At least one motor driven during image forming operation by power supplied from a power source;
A fan for flowing the air inside the device,
Power supply means for supplying power supplied from the power supply to the fan;
Regenerative means for taking out regenerative power generated before the motor stops from the motor;
Regenerative power supply means for supplying regenerative power extracted from the motor by the regenerative means to the fan;
Selecting means for selecting one of power supply to the fan by the power supply power supply means and power supply to the fan by the regenerative power supply means;
Fan control means for performing control to continue driving of the fan when power supply from the power source is interrupted during an image forming operation;
The fan control unit drives the fan in an operation mode different from that when power is supplied from the power source when power supply from the power source is interrupted during an image forming operation.
When the power supply from the power source is interrupted during the image forming operation, the regenerative unit decelerates the motor and takes out regenerative power.
The selection means supplies power to the fan by the power supply power supply means when power is supplied from the power supply, and when power supply from the power supply is interrupted during an image forming operation, Power is supplied to the fan by regenerative power supply means,
The regeneration means may obtain a large regenerative power as strong braking force acts in a short period from the start of deceleration of the motor, over time, changing weaker the braking force, the image forming apparatus .
Image forming apparatus.   The selection unit performs the selection according to a magnitude of power that can be supplied to the fan by the power source power supply means and a magnitude of power that can be supplied to the fan by the regenerative power supply means. The image forming apparatus described. The fan control unit drives the fan so that the rotation speed is lower than when power is supplied from the power source when power supply from the power source is interrupted during an image forming operation. the image forming apparatus according to claim 1 or 2. At least one motor driven during image forming operation by power supplied from a power source;
A fan for flowing the air inside the device,
A control method of an image forming apparatus comprising: a power supply means for supplying power supplied from the power supply to the fan,
A regenerative step of extracting from the motor the regenerative power generated until the motor stops;
A regenerative power supply step of supplying regenerative power extracted from the motor by the regenerative step to the fan;
A selection step of selecting one of power supply to the fan by the power supply means and power supply to the fan by the regenerative power supply step;
A fan control step for performing control to continue driving of the fan when power supply from the power source is interrupted during an image forming operation,
The fan control step drives the fan in an operation mode different from when power is supplied from the power source when power supply from the power source is interrupted during an image forming operation ,
In the regenerative step, when power supply from the power source is interrupted during the image forming operation, the motor is decelerated to take out regenerative power,
In the selection step, when power is supplied from the power source, power is supplied to the fan by the power source power supply step, and when power supply from the power source is interrupted during the image forming operation, Power is supplied to the fan through a regenerative power supply step,
In the regenerative step, an image forming apparatus that obtains a large regenerative electric power so that a strong braking force works in a period immediately after the motor starts decelerating and changes the braking force weakly as time passes. Control method. At least one motor driven during image forming operation by power supplied from a power source;
A fan for flowing the air inside the device,
A control program for an image forming apparatus, comprising: a power supply unit that supplies power supplied from the power source to the fan,
A regenerative step of extracting from the motor the regenerative power generated until the motor stops;
A regenerative power supply step of supplying regenerative power extracted from the motor by the regenerative step to the fan;
A selection step of selecting one of power supply to the fan by the power supply means and power supply to the fan by the regenerative power supply step;
When the supply of power from the power source is interrupted during an image forming operation, the computer executes a fan control step for performing control to continue driving the fan,
The fan control step drives the fan in an operation mode different from when power is supplied from the power source when power supply from the power source is interrupted during an image forming operation ,
In the regenerative step, when power supply from the power source is interrupted during the image forming operation, the motor is decelerated to take out regenerative power,
In the selection step, when power is supplied from the power source, power is supplied to the fan by the power source power supply step, and when power supply from the power source is interrupted during the image forming operation, Power is supplied to the fan through a regenerative power supply step,
In the regenerative step, an image forming apparatus that obtains a large regenerative electric power so that a strong braking force works in a period immediately after the motor starts decelerating and changes the braking force weakly as time passes. Control program.

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