Display unit reset circuit and image forming apparatus

Abstract

To enable a reset signal to be output to a display unit when stopping a power supply from a commercial power source.SOLUTION: A unit reset circuit 50 is provided with a relay 53, a secondary battery 54, and an emergency reset circuit 52. The relay 53 is operated by a power supply from a power source 1. The secondary battery 54 is electrically connected to an input terminal of a normally closed contact of the relay 53. The emergency reset circuit 52 is electrically connected to an output terminal of the relay 53 and an output line L12 of the power source 1, and outputs a reset signal to a reset terminal 2x of a display unit 2a when a voltage is supplied from the output terminal of the relay 53.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a display unit reset circuit that outputs a reset signal to a display unit when power supply from a power source is stopped, and to an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art An information processing apparatus such as an image forming apparatus includes a power supply and a display unit that operates on power supplied from the power supply. The display unit is, for example, a liquid crystal display unit.

[0003] It is known that the information processing device has a configuration that, when a commercial power outage occurs while the main power supply is off, turns on the main power supply after the commercial power supply is restored (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-123345 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the power supply to the display unit is cut off without resetting it, the display unit may enter an abnormal display state. Therefore, it is desirable to be able to output a reset signal to the display unit even when the power supply from the commercial power source is unintentionally cut off.

[0006] An object of the present invention is to provide a display unit reset circuit and an image forming apparatus that can output a reset signal to a display unit when power supply from a commercial power source is stopped. [Means for solving the problem]

[0007] A display unit reset circuit according to one aspect of the present invention includes a relay, a secondary battery, and an emergency reset circuit. The relay is operated by power from a power supply. The secondary battery is electrically connected to an input terminal of the relay's contact point b. The emergency reset circuit is electrically connected to an output terminal of the relay and an output line of the power supply, and outputs a reset signal to the reset terminal of the display unit when voltage is supplied from the output terminal of the relay.

[0008] According to another aspect of the present invention, an image forming apparatus includes a power supply, a printing device, a display unit, and the display unit reset circuit. The printing device operates using power supplied from the power supply and forms an image on a sheet. The display unit operates using power supplied from the power supply and is capable of displaying information related to the printing device. The display unit reset circuit outputs a reset signal to a reset terminal of the display unit. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a display unit reset circuit and an image forming apparatus that can output a reset signal to a display unit when the power supply from the commercial power source is stopped. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing the configuration of an image forming apparatus including a display unit reset circuit according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a display unit reset circuit according to the embodiment. [Figure 3] FIG. 3 is a circuit diagram illustrating an example of a display unit reset circuit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and does not limit the technical scope of the present invention.

[0012] [Configuration of image forming apparatus 10] The display unit reset circuit 50 according to the embodiment constitutes a part of the image forming apparatus 10.

[0013] The image forming apparatus 10 includes a power supply 1, a human interface 2, a printing device 3, a communication device 4, and a control device 5 (see FIG. 1).

[0014] The power supply 1 generates various voltages required within the image forming apparatus 10 using power supplied from a commercial power supply 100. That is, the human interface 2, the printing device 3, the communication device 4, and the control device 5 operate using the power supplied from the power supply 1.

[0015] For example, the power supply 1 converts AC voltage supplied from a commercial power supply 100 into various DC voltages required by the printing device 3, the communication device 4, and the control device 5.

[0016] The human interface 2 includes a display unit 2a and an operating device 2b. Each of the display unit 2a and the operating device 2b operates using power supplied from a power supply 1. In this embodiment, the display unit 2a is a liquid crystal display unit. However, the display unit 2a may be another display panel unit such as an organic electroluminescence panel unit.

[0017] The display unit 2a displays information related to the printing device 3 and the communication device 4. For example, the display unit 2a can display information related to various printing parameters in the printing device 3, the progress of the printing process, various errors, and the like.

[0018] The operation device 2b is a device that accepts human operations. For example, the operation device 2b includes one or both of a touch panel and one or more operation buttons that are integrated with the display unit 2a. For example, the operation device 2b accepts operations such as specifying information to be displayed on the display unit 2a and setting the print parameters.

[0019] The printing device 3 feeds a sheet 9 from a sheet storage unit (not shown), and forms an image on the sheet 9 while further transporting the sheet 9 .

[0020] For example, the printing device 3 forms an image on the sheet 9 by electrophotography or inkjet printing. The sheet 9 is an image forming medium such as paper or a resin sheet.

[0021] The communication device 4 executes communication with other devices. For example, the communication device 4 receives print job data from a host device (not shown) via a network such as a LAN (Local Area Network), and transmits the print job data to the control device 5.

[0022] The control device 5 controls various devices in the image forming apparatus 10, including the display unit 2a, the printing device 3, and the communication device 4.

[0023] The control device 5 includes a CPU (Central Processing Unit) 5a, a secondary storage device 5b, a signal interface 5c, etc. The CPU 5a executes computer programs stored in the secondary storage device 5b to perform various controls and data processing.

[0024] The secondary storage device 5b is a computer-readable non-volatile storage device. The secondary storage device 5b stores various data such as the computer program and the print job data. For example, a flash memory or a hard disk drive, or both, may be used as the secondary storage device 5b.

[0025] The signal interface 5c converts the detection signals of various sensors into digital detection data, which is then transmitted to the CPU 5a. The signal interface 5c then converts the various control commands output from the CPU 5a into control signals, which are then transmitted to the controlled devices.

[0026] For example, the signal interface 5c includes a display control circuit that converts a display control command for the display unit 2a into a display control signal and transmits the display control signal to the display unit 2a.

[0027] However, if the power supply to the display unit 2a is stopped without resetting it, an abnormal display state may occur. For example, the display unit 2a may display a line-shaped or dot-shaped noise image. Therefore, it is desirable to be able to output a reset signal to the display unit 2a even when the power supply from the commercial power source 100 is unintentionally stopped.

[0028] In this embodiment, the signal interface 5c includes a display unit reset circuit 50 (see FIGS. 2 and 3). The display unit reset circuit 50 is mounted on a control board 5x that constitutes a part of the control device 5.

[0029] The display unit reset circuit 50 outputs a reset signal RS1 to the reset terminal 2x of the display unit 2a. The display unit reset circuit 50 includes a normal reset circuit 501, an emergency reset circuit 502, a relay 53, and a secondary battery .

[0030] The display unit reset circuit 50 also includes a plurality of voltage output lines of the power supply 1. The plurality of voltage output lines include a first voltage output line L11, a second voltage output line L12, and a third voltage output line L13.

[0031] The display unit reset circuit 50 further includes a command transmission line L2 for transmitting a reset command signal CM1 and a reset transmission line L3 for transmitting a reset signal RS1. The reset command signal CM1 is one of the control command signals output from the CPU 5a.

[0032] The normal reset circuit 501 operates using power supplied from the power supply 1. When a reset command signal CM1 is input, the normal reset circuit 501 outputs a reset signal RS1. The normal reset circuit 501 outputs the reset signal RS1 to the reset terminal 2x via a reset transmission line L3.

[0033] The normal reset circuit 501 includes a first delay circuit 511 and a first switch circuit 512. The first delay circuit 511 is electrically connected to a command transmission line L2 that transmits a reset command signal CM1.

[0034] The first delay circuit 511 delays the reset command signal CM1 when the reset command signal CM1 is input, and outputs a first delay signal DS1, which is a delayed version of the reset command signal CM1, to the first switch circuit 512.

[0035] The first switch circuit 512 is electrically connected to the first voltage output line L11. When the power supply 1 is operating, a first control voltage VC1 is supplied to the first switch circuit 512 through the first voltage output line L11.

[0036] The first switch circuit 512 transmits the first control voltage VC1 to the reset terminal 2x when the first delay signal DS1 is in a negative state, and stops transmitting the first control voltage VC1 to the reset terminal 2x when the first delay signal DS1 is in an active state.

[0037] By stopping the transmission of the first control voltage VC1 to the reset terminal 2x, the input voltage of the reset terminal 2x becomes zero level.

[0038] As described above, the normal reset circuit 501 switches from a state in which the first control voltage VC1 is output to the reset terminal 2x to a state in which zero voltage is output to the reset terminal 2x by the time the delay time of the first delay circuit 511 has elapsed since the reset command signal CM1 was input.

[0039] In this embodiment, the reset signal RS1 is a voltage signal that changes from a reference level range to a zero level, and the level of the first control voltage VC1 is included in the reference level range.

[0040] The relay 53 is operated by the power of the power supply 1. Specifically, the relay 53 is operated by the current supplied through the third voltage output line L13 when the drive voltage VD1 is output to the third voltage output line L13.

[0041] The secondary battery 54 is electrically connected to the input terminal of the contact b of the relay 53. For example, the secondary battery 54 is a lithium ion battery. The relay output terminal LO1, which is the output terminal of the relay 53, is electrically connected to the emergency reset circuit 502.

[0042] When the drive voltage VD1 is not output to the third voltage output line L13, the relay 53 outputs to the relay output terminal LO1 the battery voltage VB1, which is the output voltage of the secondary battery 54. On the other hand, when the drive voltage VD1 is output to the third voltage output line L13, the relay 53 does not output the battery voltage VB1 to the relay output terminal LO1.

[0043] The emergency reset circuit 502 is electrically connected to the relay output terminal LO1 and the second voltage output line L12. When a voltage is supplied from the relay output terminal LO1 or the second voltage output line L12, the emergency reset circuit 502 outputs a reset signal RS1 to the reset terminal 2x of the display unit 2a.

[0044] When the power supply 1 is operating, a second control voltage VC2 is provided to the second voltage output line L12.

[0045] The emergency reset circuit 502 includes a second delay circuit 521 and a second switch circuit 522. The second delay circuit 521 is electrically connected to the second voltage output line L12 and the relay output terminal LO1.

[0046] The input line LIN1 of the second delay circuit 521 is electrically connected to the relay output terminal LO1 and the second voltage output line L12. The second delay circuit 521 delays a specific voltage when the specific voltage is input to the input line LIN1. The second delay circuit 521 outputs a second delay signal DS2, which is a delayed version of the specific voltage signal, to the second switch circuit 522.

[0047] The specific voltage is the second control voltage VC2 or the battery voltage VB1. Specifically, when the power supply 1 is operating, the specific voltage is the second control voltage VC2. On the other hand, when the power supply 1 is not operating, the specific voltage is the battery voltage VB1. The level of the second control voltage VC2 and the level of the battery voltage VB1 are included in the reference level range.

[0048] The second switch circuit 522 is electrically connected to the relay output terminal LO1 and the second voltage output line L12.

[0049] The second switch circuit 522 transmits the specific voltage to the reset terminal 2x when the second delay signal DS2 is in a negative state, and stops transmitting the specific voltage to the reset terminal 2x when the second delay signal DS2 is in an active state.

[0050] When the transmission of the specific voltage to the reset terminal 2x is stopped, the input voltage to the reset terminal 2x becomes zero level.

[0051] The emergency reset circuit 502 switches from a state in which the battery voltage VB1 is output to the reset terminal 2x to a state in which zero voltage is output to the reset terminal 2x until the delay time of the second delay circuit 521 has elapsed since the operation of the power supply 1 stopped.

[0052] That is, when the operation of the power supply 1 stops, the emergency reset circuit 502 reliably outputs the reset signal RS1 to the reset terminal 2x.

[0053] Furthermore, the emergency reset circuit 502 switches from a state in which the second control voltage VC2 is output to the reset terminal 2x to a state in which zero voltage is output to the reset terminal 2x by the time the delay time of the second delay circuit 521 has elapsed since the power supply 1 was started.

[0054] That is, even when the power supply 1 is started, the emergency reset circuit 502 outputs the reset signal RS1 to the reset terminal 2x.

[0055] Furthermore, when the power supply 1 is operating, the relay 53 operates to electrically insulate the output line of the secondary battery 54. This prevents the secondary battery 54 from wasting power when the power supply 1 is operating.

[0056] A specific example of the display unit reset circuit 50 will be described below with reference to FIG.

[0057] In the example shown in FIG. 3, the first delay circuit 511 and the second delay circuit 521 are each configured by an RC circuit.

[0058] In the example shown in FIG. 3, the first switch circuit 512 is configured by a field effect transistor.

[0059] In the example shown in FIG. 3, the first switch circuit 512 transmits the first control voltage VC1 on the first voltage output line L11 to the reset terminal 2x when the voltage of the first delay signal DS1 falls below the first operating level.

[0060] On the other hand, the first switch circuit 512 stops transmitting the first control voltage VC1 to the reset terminal 2x when the voltage of the first delay signal DS1 exceeds the first operating level.

[0061] The first operating level is the operating voltage level of the field-effect transistor. In the example shown in Figure 3, the state in which the voltage of the first delay signal DS1 is below the first operating level is the negative state of the first delay signal DS1. On the other hand, the state in which the voltage of the first delay signal DS1 is above the first operating level is the active state of the first delay signal DS1.

[0062] In the example shown in FIG. 3, the second switch circuit 522 is configured by a first transistor 522a and a second transistor 522b.

[0063] In the example shown in FIG. 3, the second switch circuit 522 transmits the specific voltage to the reset terminal 2x when the voltage of the second delayed signal DS2 falls below the second operating level.

[0064] On the other hand, the second switch circuit 522 stops transmitting the specific voltage to the reset terminal 2x when the voltage of the second delay signal DS2 exceeds the second operating level.

[0065] The second operating level is the operating voltage level of the first transistor 522a. In the example shown in Figure 3, the state in which the voltage of the second delay signal DS2 is below the second operating level is the negative state of the second delay signal DS2. On the other hand, the state in which the voltage of the second delay signal DS2 is above the second operating level is the active state of the second delay signal DS2.

[0066] Furthermore, the normal reset circuit 501 includes a first diode 513 connected to an output line of the reset signal RS1 in the normal reset circuit 501. The normal reset circuit 501 outputs the reset signal RS1 through the first diode 513 to the reset terminal 2x.

[0067] Similarly, the emergency reset circuit 502 includes a second diode 523 connected to the output line of the reset signal RS1 in the emergency reset circuit 502. The emergency reset circuit 502 outputs the reset signal RS1 to the reset terminal 2x through the second diode 523.

[0068] The second diode 523 prevents a current caused by the voltage output from the normal reset circuit 501 from flowing back in the emergency reset circuit 502. The first diode 513 prevents a current caused by the voltage output from the emergency reset circuit 502 from flowing back in the normal reset circuit 501.

[0069] By employing the display unit reset circuit 50, the reset signal RS1 is reliably output to the reset terminal 2x of the display unit 2a when the power supply from the commercial power source 100 to the power source 1 is stopped. As a result, when the power supply from the commercial power source 100 to the power source 1 is stopped, it is possible to prevent the display unit 2a from entering an abnormal display state.

[0070] Furthermore, the display unit reset circuit 50 reliably outputs the reset signal RS1 to the reset terminal 2x of the display unit 2a even when the power supply 1 is started.

[0071] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0072] <Appendix 1> a relay operated by power from a power supply; a secondary battery electrically connected to an input terminal of the b-contact of the relay; a display unit reset circuit comprising: an emergency reset circuit electrically connected to the output terminal of the relay and the output line of the power supply, and outputting a reset signal to the reset terminal of the display unit when a voltage is supplied from the output terminal of the relay or the output line of the power supply.

[0073] <Appendix 2> The display unit reset circuit described in Appendix 1 includes a normal reset circuit that operates using power supplied from the power supply and outputs the reset signal to the reset terminal when a reset command signal is input.

[0074] <Appendix 3> the normal reset circuit includes a first diode connected to an output line of the reset signal in the normal reset circuit, and outputs the reset signal to the reset terminal through the first diode; The display unit reset circuit described in Appendix 2, wherein the emergency reset circuit includes a second diode connected to an output line of the reset signal in the emergency reset circuit, and outputs the reset signal to the reset terminal through the second diode.

[0075] <Appendix 4> The emergency reset circuit a delay circuit that delays a specific voltage when the specific voltage is input to an input line electrically connected to the output terminal of the relay and the output line of the power supply; a switch circuit that transmits the voltage of the input line to the reset terminal when the output voltage of the delay circuit falls below an operating level, and stops transmitting the voltage of the input line to the reset terminal when the output voltage of the delay circuit exceeds the operating level; 4. The display reset circuit according to any one of claims 1 to 3, wherein the reset signal is a voltage signal that changes from a reference level range that includes the level of the specific voltage to a zero level.

[0076] <Appendix 5> Power supply and a printing device that operates using power supplied from the power source and forms an image on a sheet; a display unit that operates using power supplied from the power source and is capable of displaying information about the printing device; an image forming apparatus comprising: a display unit reset circuit according to any one of Supplementary Note 1 to Supplementary Note 4, which outputs a reset signal to a reset terminal of the display unit; [Explanation of symbols]

[0077] 1: Power supply 2a: Display unit 2x: Reset terminal 5x: Control board 10: Image forming device 50: Display unit reset circuit 53: Relay 54: Secondary battery 100: Commercial power supply 501: Normal reset circuit 502: Emergency reset circuit 511: First delay circuit 512: First switch circuit 513: First diode 521: Second delay circuit 522: Second switch circuit 523: Second diode

Claims

1. a relay operated by power from a power supply; a secondary battery electrically connected to an input terminal of the b-contact of the relay; a display unit reset circuit comprising: an emergency reset circuit electrically connected to the output terminal of the relay and the output line of the power supply, and outputting a reset signal to the reset terminal of the display unit when a voltage is supplied from the output terminal of the relay or the output line of the power supply.

2. 2. The display unit reset circuit according to claim 1, further comprising a normal reset circuit that operates using power supplied from the power supply and outputs the reset signal to the reset terminal when a reset command signal is input.

3. the normal reset circuit includes a first diode connected to an output line of the reset signal in the normal reset circuit, and outputs the reset signal to the reset terminal through the first diode; 3. The display unit reset circuit according to claim 2, wherein the emergency reset circuit includes a second diode connected to an output line of the reset signal in the emergency reset circuit, and outputs the reset signal to the reset terminal through the second diode.

4. The emergency reset circuit a delay circuit that delays a specific voltage when the specific voltage is input to an input line electrically connected to the output terminal of the relay and the output line of the power supply; a switch circuit that transmits the voltage of the input line to the reset terminal when the output voltage of the delay circuit falls below an operating level, and stops transmitting the voltage of the input line to the reset terminal when the output voltage of the delay circuit exceeds the operating level; 4. The display unit reset circuit according to claim 1, wherein the reset signal is a voltage signal that changes from a reference level range including the level of the specific voltage to a zero level.

5. Power supply and a printing device that operates using power supplied from the power source and forms an image on a sheet; a display unit that operates using power supplied from the power source and is capable of displaying information about the printing device; 4. An image forming apparatus comprising: a display unit reset circuit according to claim 1, which outputs a reset signal to a reset terminal of the display unit.

Images