JP2007171741A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that has simple constitution and can maintain a state of communication with an external device if external power supply is ceased. <P>SOLUTION: The image forming apparatus 1 which forms an image based upon an image signal sent from the external device on a form has: an image forming mechanism unit 11 which is operative to form an image under control; a control unit 12 which receives the image signal sent from the external device and controls the operation of the image forming mechanism unit 11 to make the image forming mechanism unit 11 form the image based upon the image signal on the form; an uninterruptible power supply unit 13 which inputs electric power supplied from outside, outputs the electric power while accumulating it, and outputs its accumulated electric power when the external power supply is stopped, and power supply paths 14a and 14b which supply the externally supplied electric power to the image forming mechanism unit while bypassing the uninterruptible power supply unit 13 and also supplies the electric power to the control unit 12 through a path wherein the uninterruptible power supply unit 13 is interposed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet based on an image signal transmitted from an external apparatus.

  An image forming apparatus that receives an image signal transmitted from an external device such as a computer and forms an image based on the image signal on a sheet is widely used as a printer or the like. The image forming apparatus normally operates with power supplied from the outside such as a commercial power source. However, even when the external power supply is stopped, the setting state in the image forming apparatus and the received image signal In order to maintain the contents, the image forming apparatus is connected to an uninterruptible power supply (UPS).

  FIG. 4 is a block diagram illustrating the configuration of an image forming apparatus and a UPS in the prior art as an example of a printer.

  A UPS 502 is connected to the printer 501, and power supplied from an external commercial power source is supplied to the printer 501 via the UPS 502. The printer 501 communicates with an external host computer, receives an image signal transmitted from the host computer, and forms an image based on the image signal on a sheet. When the power supply from the commercial power supply is stopped due to a power failure or the like, the UPS 502 supplies the power stored in the printer 501 to maintain the function of the printer 501.

By the way, the image forming apparatus includes, for example, a rotating photosensitive drum, an exposure unit that irradiates the photosensitive drum with exposure light, a developing unit that develops toner, a transfer unit that transfers a toner image onto a sheet, and toner on the sheet. A mechanism for forming an image on a sheet, such as a fixing unit for fixing, is provided. Since the power consumed by these mechanisms is large, the time during which the uninterruptible power supply can supply power to the image forming apparatus is limited. In particular, when the image forming apparatus is a large one used for commercial printing work, it is difficult to maintain the entire function of the image forming apparatus with the UPS. Here, in Patent Document 1, when a digital multi-function peripheral, which is an example of an image forming apparatus, is connected to a UPS and the digital multi-function peripheral receives a power failure signal transmitted from the UPS, a fixing heater in the digital multi-function peripheral is detected. A technique for turning off a portion is disclosed. According to this technique, power consumption is reduced, and the contents of the image signal received from the host computer and the internal state set by the host computer are maintained for a long time by the UPS.
JP 2001-253152 A

  However, in the technique of the above-mentioned patent document 1, since it is necessary to control the switching of the heater power on / off by receiving a signal from the UPS and discriminating it inside the digital multi-function peripheral, the configuration of the apparatus is complicated. As a result, the cost also increases.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus having a simple configuration and capable of maintaining an internal state for a long time even when external power supply is stopped.

An image forming apparatus of the present invention that achieves the above object is an image forming apparatus that forms an image on a sheet based on an image signal transmitted from an external device.
An image forming mechanism that operates for image formation under control;
A control unit that receives an image signal transmitted from the external device, controls the operation of the image forming mechanism unit, and causes the image forming mechanism unit to form an image based on the received image signal on a sheet;
An uninterruptible power supply that outputs the stored electric power while inputting the electric power supplied from outside and storing the input electric power, and outputting the stored electric power when the external power supply is stopped,
A power supply path for supplying power supplied from the outside to the image forming mechanism section through a path bypassing the uninterruptible power supply apparatus, and supplying the control section through the path with the uninterruptible power supply apparatus interposed therebetween It is characterized by having.

  The image forming apparatus according to the present invention has a path bypassing the uninterruptible power supply that supplies power to the image forming mechanism unit separately from a path through which the uninterruptible power supply is supplied to supply power to the control unit. ing. For this reason, when power supply from the outside is stopped, power is supplied to the control unit by the uninterruptible power supply, but power supply to the image forming mechanism unit is automatically stopped. Therefore, it is not necessary to control the power on / off of the image forming mechanism, and the simple configuration reduces the power consumption when the external power supply is stopped, and the uninterruptible power supply unit extends the internal state. Maintained for hours.

  Here, in the image forming apparatus of the present invention, the control unit is directed to the external device for a predetermined time during which the power stored in the uninterruptible power supply is received after the external power supply is stopped. It is preferable to request that the transmission of the image signal be stopped and to notify the external device that the power has been turned off after the predetermined time has elapsed.

  The control unit notifies the external device that the power supply has been turned off after the predetermined time has elapsed after stopping the power supply from the outside, but until then, without notifying that the power supply has been cut off. , Request to stop the transmission of the image signal. Therefore, when the external power supply is restored within this predetermined time, the external device can store the image information without executing the recovery processing from the power-off such as initialization of the image forming device and retransmission of the image signal. Continue sending. Therefore, the processing burden on the external device is reduced.

  As described above, according to the present invention, an image forming apparatus that can maintain a communication state with an external apparatus when an external power supply is stopped is realized with a simple configuration.

  Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a printer which is an embodiment of an image forming apparatus of the present invention.

  The printer 1 shown in FIG. 1 forms an image based on an image signal transmitted from a host computer 30 as an external device on a sheet by an electrophotographic method, and an image forming mechanism that operates for image formation. Unit 11, control unit 12 that controls the operation of image forming mechanism unit 11, uninterruptible power supply 13 (hereinafter referred to as UPS 13), and power supply that supplies power to image forming mechanism unit 11 and control unit 12. Path 14 (14a, 14b). The printer 1 is supplied with power from an external commercial power supply 40.

  Although not shown, the image forming mechanism unit 11 includes a photosensitive drum that is driven and rotated by a motor, a charging unit that uniformly charges the surface of the photosensitive drum with a discharger, and exposure light from a laser light oscillator to the photosensitive drum. , An exposure unit that forms an electrostatic latent image on the photosensitive drum, a development unit that forms a toner image by developing the electrostatic latent image on the photosensitive drum with toner, and a toner image on the paper A transfer unit that transfers the toner image, a fixing unit that fixes the toner image transferred onto the sheet with heat from a heater, and a sheet conveyance unit that conveys the sheet. Each unit of the image forming mechanism unit 11 includes an electric circuit for transmitting / receiving a signal to / from the control unit 12 and driving a motor, a laser light oscillator, a heater, and the like according to the received signal. The image forming mechanism unit 11 transmits a request signal Rdy1 to the control unit 12 and receives a control signal from the control unit 12. The image forming mechanism unit 11 requests the control unit 12 to transmit a control signal by driving the request signal Rdy1 transmitted to the control unit 12 to an active level. Each part of the image forming mechanism 11 operates according to the control signal transmitted from the controller 12, thereby forming an image on the sheet. In other words, an electrostatic latent image is formed by irradiating exposure light onto the photosensitive drum whose exposure unit rotates, and the toner image developed from the electrostatic latent image by the developing unit is applied to the paper conveyed by the transfer unit. The image is transferred and fixed on the paper by the fixing unit. The image forming mechanism unit 11 requests the control unit 12 to stop transmitting the control signal by driving the request signal Rdy1 to the inactive level while it cannot respond to the control signal transmitted next. The request signal Rdy1 is not driven when the supply of power to the image forming mechanism unit 11 is stopped, and consequently becomes an inactive level.

  The control unit 12 receives an image signal transmitted from the host computer 30 as an external device. Although not shown in the figure, the control unit 12 controls the overall operation of the image forming system based on a program, a ROM that stores programs and tables, and a temporary storage area in the CPU. A RAM to be provided and an interface circuit for relaying signals between the outside of the control circuit 26 and the CPU are provided. The operation of the control unit 12 is controlled based on a program executed by the CPU. In addition, the control unit 12 includes a buffer 12a that stores the content of the received image signal, that is, the information of the image transmitted by the image signal. The content of the received image signal is once written in the buffer 12a. Specifically, the control unit 12 requests the host computer 30 to transmit an image signal by driving the request signal Rdy2 to an active level. When an image signal is transmitted from the host computer 30, the control unit 12 writes the content of the image signal into the buffer 12a, and when the writing is performed up to the capacity limit of the buffer 12a, drives the request signal Rdy2 to the inactive level. As a result, the host computer 30 is requested to stop transmitting image signals. A signal for setting the state of the printer 1 is also transmitted from the host computer 30, but the control unit 12 also writes the setting contents in the buffer 12a. In addition, the control unit 12 reads the content of the image signal written in the buffer 12a and transmits a control signal to the image forming mechanism unit 11 according to the read content. Accordingly, the control unit 12 causes the image forming mechanism unit 11 to form an image based on the image signal received from the host computer 30 on the sheet. Specifically, when the request signal Rdy1 transmitted from the image forming mechanism unit 11 is an active level indicating a control signal transmission request, the control unit 12 reads and reads the content of the image signal from the buffer 12a. A control signal corresponding to the contents is transmitted to the image forming mechanism unit 11.

  In addition, the control unit 12 monitors a signal Sstop that is output from the UPS 13 and represents the stop of power supply from the commercial power supply 40. When a predetermined backup time has elapsed with the power supply from the commercial power supply 40 stopped, the control unit 12 sends a shutdown signal Sdown to the host computer 30 to notify the printer 1 that the power supply has been cut off. Perform the shutdown process. As a result, all functions of the printer 1 are stopped, and the contents stored in the buffer 12a are lost. The backup time is set to a time shorter than the time that the UPS 13 can supply power when the power supply from the commercial power supply 40 is stopped based on the capacity of the UPS 13 for storing power and the power consumption of the control unit 12. .

  The UPS 13 is a device for preventing all the functions of the printer 1 from stopping when the power supply from the commercial power supply 40 is stopped for some reason. The UPS 13 inputs the power supplied from the outside. While storing and outputting the input electric power, the stored electric power is output when power supply from the outside is stopped. The detailed configuration of the UPS 13 will be described later.

  The power supply path 14 (14 a, 14 b) supplies power from the external commercial power supply 40 to each part of the printer 1. The power supply path 14 a forms a path for supplying power from the commercial power supply 40 to the image forming mechanism unit 11 by bypassing the UPS 13, and the second power supply path 14 b supplies the power from the commercial power supply 40 to the UPS 13. , A path for supplying to the control unit 12 through the UPS 13 is formed.

  FIG. 2 is a block diagram showing the configuration of the UPS.

  The UPS 13 rectifies the power supplied from the commercial power supply 40 by the second power supply path 14b, the storage battery 132 that stores the power, and either the power from the rectifier 131 or the power from the storage battery 132. And a switching unit 133 that switches to output to the second power supply path 14b. The rectifier 131 stores power in the storage battery 132 when power is not stored in the storage battery 132. The switching unit 133 detects the voltage of the power supplied from the rectifier 131 to determine whether the power is normally supplied from the commercial power supply 40 or the supply is stopped. When the switching unit 133 determines that the power from the commercial power source 40 is normally supplied, the switching unit 133 outputs the power supplied from the rectifier 131 to the second power supply path 14b, and the power from the commercial power source 40 is output. When it is determined that the supply is stopped, a signal Sstop indicating the stop of the supply of power from the commercial power supply 40 is transmitted to the control unit 12, and at the same time, the power supplied from the storage battery 132 is sent to the second power supply path 14b. Output. Thereby, even if the power supply from the commercial power supply 40 is stopped for some reason such as a power failure, the power required for the operation of the control unit 12 is supplied to the second power supply until the power stored in the storage battery 132 is consumed. It is supplied to the control unit 12 through the path 14b. When the power supply from the commercial power supply 40 is restored, the transmission of the signal Sstop indicating the power supply stop from the commercial power supply 40 is stopped and the power from the commercial power supply 40 is supplied to the control unit 12 through the power supply path 14b. Is done.

  Here, returning to FIG. 1, the description will be continued.

  The printer 1 is divided according to the type of path through which power is supplied. One is the image forming mechanism 11 that is supplied with power through a path bypassing the UPS 13 and formed by the second power supply path 14b, and the other is formed by the first power supply path 14a. The control unit 12 is supplied with electric power through a path through which the UPS 13 is interposed. With such a configuration, when power supply from the commercial power supply 40 is stopped, power is supplied to the control unit 12 by the UPS 13, but power supply to the image forming mechanism unit 11 is automatically stopped. Is reduced. Therefore, the contents of the image signal received from the host computer 30 and the internal state set by the host computer 30 are maintained for a long time by the UPS.

  FIG. 3 is a timing chart showing an example of the operation of each part of the printer.

  Here, the operation of the printer 1 when the power supply from the commercial power supply 40 is stopped will be described with reference to FIG.

  In the chart of FIG. 3, the power from the commercial power supply 40 is normally supplied to the printer 1 in a state before the time tstop. In this state, the power Ps is supplied from the commercial power supply 40 to the image forming mechanism unit 11 through the first power supply path 14a, and the control unit 12 is connected via the UPS 13 through the second power supply path 14b. Electric power Pu is supplied. At this time, the UPS 13 outputs the power supplied from the commercial power supply 40 to the power supply path 14b while storing the power in the storage battery 132 (see FIG. 2). When power is supplied from the commercial power supply 40, the image forming mechanism unit 11 drives the request signal Rdy1 to the H level as an active level that means a transmission request in accordance with the operation status of the image forming mechanism unit 11. To do. When the request signal Rdy1 is driven to the H level, the control unit 12 transmits a control signal to the image forming mechanism unit 11. When there is room for writing to the buffer 12a, the control unit 12 drives the request signal Rdy2 to the H level as the active level and requests the host computer 30 to transmit an image signal. When the request signal Rdy2 is driven to the H level, the host computer 30 transmits an image signal to the control unit 12.

  At time tstop, when the supply of power Ps to the image forming mechanism unit 11 is stopped due to a power failure of the commercial power supply 40, the image forming mechanism unit 11 stops operating. At this time, the request signal Rdy1 from the image forming mechanism unit 11 is fixed to the L level as the inactive level. Since the UPS 13 supplies the power stored in the storage battery 132 to the control unit 12, the control unit 12 continues to operate. Further, since the contents of the buffer 12a are also maintained, the contents and settings of the image signal transmitted from the external device are maintained. However, since the control unit 12 cannot read the content of the image signal from the buffer 12a and transmit the control signal to the image forming mechanism unit 11, the buffer 12a becomes full. As a result, the control unit 12 drives the request signal Rdy2 to the L level as the inactive level, and requests the host computer 30 to stop transmitting the image signal. In the state where the request signal Rdy2 is driven to the L level, the host computer 30 only stops the transmission of the image signal and recognizes that the power supply from the commercial power supply 40 to the printer 1 is stopped. Not. In other words, for example, it is merely recognized that the state is the same as when there is no paper for image formation.

  When power supply from the commercial power supply 40 is recovered from time tstop at time trecover before the backup time elapses, power Ps is supplied to the image forming mechanism unit 11, and the image forming mechanism unit 11 resumes operation. The request signal Rdy1 from the image forming mechanism unit 11 returns to the H level, and the control unit 12 transmits the control signal again. When the control unit 12 transmits a control signal to the image forming mechanism unit 11 and there is room in the buffer 12a, the control unit 12 drives the request signal Rdy2 to H level and transmits an image signal to the host computer 30. Request. As a result, the host computer 30 can continue the transmission of the image signal.

  However, if the signal Sstop indicating the stop of power supply from the commercial power supply 40 remains at the active level even after the backup time has elapsed from the time tstop, that is, the power supply from the commercial power supply 40 remains stopped. In this case, the control unit 12 sends a shutdown signal Sdown to the host computer 30 to notify the host computer 30 that the power supply has been cut off, assuming that the supply of power Pu by the UPS 13 is close to the capacity limit, and performs a shutdown process of the printer 1. All functions of the printer 1 are stopped. When the function of the printer 1 is stopped, the contents stored in the buffer 12a are lost. Accordingly, when the power supply from the commercial power supply 40 is subsequently recovered, the host computer 30 initializes the printer 1 and transmits image data corresponding to the amount lost from the buffer 12a to the printer 1 again. .

  As described above, according to the printer 1 of the present embodiment, when the external power supply is stopped, power is supplied to the control unit 12 by the UPS 13, but power supply to the image forming mechanism unit 11 is automatically performed. Stop. Therefore, with a simple configuration, the power consumption when the external power supply is stopped is reduced, and the internal state is maintained for a long time by the power supply from the UPS 13.

  Further, in the printer 1 of the present embodiment, the control unit 12 stops the power supply from the commercial power supply 40 and then the power supply to the host computer 30 is cut off during the backup time during which the power stored in the UPS 13 is received. Is requested to stop the transmission of the image signal. Therefore, when the power supply from the commercial power supply 40 is restored and the image formation is started within the backup time, the host computer 30 does not execute the recovery process from the shutdown such as the initialization of the printer 1, and Continue sending information. Further, the host computer 30 does not need to determine whether or not recovery processing from shutdown is necessary. Therefore, the processing burden on the host computer 30 is reduced.

  Although the printer 1 of the present embodiment has been described as forming an image on a sheet by an electrophotographic method, the method of forming an image in the image forming apparatus of the present invention is not limited to the electrophotographic method.

1 is a block diagram illustrating a configuration of a printer that is an embodiment of an image forming apparatus of the present invention. FIG. It is a block diagram which shows the structure of UPS. 6 is a timing chart illustrating an example of the operation of each unit of the printer. FIG. 2 is a block diagram illustrating a configuration of an image forming apparatus and a UPS according to a conventional technique as an example of a printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 11 Image formation mechanism part 12 Control part 12a Buffer 13 Uninterruptible power supply 14 (14a, 14b) Power supply path 26 Control circuit

Claims (2)

An image forming apparatus that forms an image on a sheet based on an image signal transmitted from an external device,
An image forming mechanism that operates for image formation under control;
A control unit that receives an image signal transmitted from the external device, controls the operation of the image forming mechanism unit, and causes the image forming mechanism unit to form an image on a sheet based on the received image signal;
An uninterruptible power supply that outputs the stored electric power while inputting the electric power supplied from outside and storing the input electric power, and outputting the stored electric power when the external power supply is stopped,
A power supply path for supplying power supplied from the outside to the image forming mechanism section via a path bypassing the uninterruptible power supply apparatus, and supplying the control section via the uninterruptible power supply apparatus An image forming apparatus comprising:   The control unit requests the external device to stop transmission of an image signal for a predetermined time during which the power stored in the uninterruptible power supply is received after the external power supply is stopped. The image forming apparatus according to claim 1, wherein the image forming apparatus notifies the external apparatus that power has been cut off after a lapse of time.

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