JP2005315923A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of determining whether the factor for starting electric power supply is either from a power-on from a power source stop state of the apparatus or a reset from a power saving state where part of the power supply is stopped and displaying the image meeting the factor for the starting on a display means at the time of starting the electric power supply. <P>SOLUTION: In the image forming apparatus, the determination of the factor for starting the electric power supply is performed by that a CPU 252 determines a signal Q 1 outputted from an output terminal 282 of a delay type flip-flop circuit 28. The CPU 252 determines that the factor for the start is by the power-on when the signal Q 1 is in an L level, and determines that the factor for the start is by the reset from the power saving state when the signal Q 1 is in an H level. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile. In particular, the power supply start factor is the power saving from the power-off state of the apparatus or partial power supply is stopped. The present invention relates to a circuit technique for determining which of the return from the power state.

  In a conventional image forming apparatus, for the purpose of power saving, when a predetermined condition is satisfied such as when the apparatus has not been operated for a predetermined time, the power supply is stopped and the power supply is stopped. However, the power supply to the unaffected part is stopped, the power supply to the remaining part is not stopped, and when the return of the stopped power supply is requested, the return key is pressed, data is received from the external interface, etc. There is an image forming apparatus having a power saving function in which power supply is restored again by a predetermined instruction.

For example, an image forming apparatus provided with an operation display substrate for controlling a liquid crystal display (abbreviated as LCD [Liquid Crystal Display]) serving as a display means and an operation means, a return key, and the like separately from a main substrate for performing main control of the apparatus In the power saving state, the power supply to the liquid crystal display, which is a portion that does not hinder the power supply even when the power supply is stopped, is stopped, and the power consumption of the operation display board is reduced. An electronic device aimed at power saving has been disclosed and proposed (see, for example, Patent Document 1).
JP 2002-345166 A

  Certainly, in the case of an image forming apparatus having the above-described configuration, when a predetermined condition is satisfied such as when the apparatus has not been operated for a predetermined time, the power supply state is stopped and power supply to the liquid crystal display is stopped. Therefore, it is possible to achieve power saving of the operation display board.

  However, in order to further reduce the power consumption of the operation display board, it is effective to stop the power supply to the part other than the liquid crystal display connected to the operation display board. However, in practice, it is necessary to display a different image on the liquid crystal display panel according to the power supply start factor in order to inform the user of the state when the device is turned on from the power stop state or returned from the power saving state. There is. Therefore, an operation display control composed of a central processing unit (hereinafter referred to as CPU [Central Processing Unit]) and an application specific integrated circuit (hereinafter referred to as ASIC [Application Specific Integrated Circuit]) disposed on the operation display board. The unit needs to determine the power supply start factor and control the display image on the liquid crystal display panel in accordance with the start factor. Therefore, power must be continuously supplied to the operation display control unit on the operation display board. Therefore, further power saving of the operation display board has been difficult.

  It should be noted that the display content on the liquid crystal display panel due to the start factor is, for example, that it takes some time for the main board to perform main control of the entire apparatus to start when power supply is started by turning on the power. Therefore, the operation display control unit on the operation display board first does not wait for an instruction from the main board that controls the entire apparatus, so that the logo is immediately displayed. The initial screen such as type and startup message is displayed on the LCD panel.

  Further, when returning from the power saving state, for example, in order to give the user an impression that the return operation has been completed early and to know the state immediately before the transition to the power saving state, the operation display control unit on the operation display board is The screen immediately before the transition to the power saving state is displayed on the liquid crystal display panel.

  In view of the above problems, the present invention aims to further reduce the power consumption of the apparatus without hindering the determination of the power-on status, and the power supply start factor is the power supply from the power-off state of the apparatus. Image formation that can determine whether the power supply state has been turned on or has returned from a power-saving state in which part of the power supply has been stopped, and can display an image corresponding to the start factor on the display means when the power supply is started An object is to provide an apparatus.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a calculation unit that performs predetermined signal processing, and a unit that controls power supply to the calculation unit. A power supply unit having a function of resuming power supply in response to a predetermined return instruction while temporarily stopping supply, and a capacitor unit that accumulates electric charges when the return instruction is issued, When the power supply from the power supply unit is supplied, the arithmetic unit may determine whether the power supply is turned on for the first time or returned from the paused state according to the stored voltage of the capacity unit.

  Moreover, it is good to have a means to discharge the said capacity | capacitance part based on the instruction | indication from the said calculating part which received the electric power supply from the said power supply part.

  Further, it is preferable to have means for holding the stored voltage of the capacity unit for a predetermined time after the discharge and continuously sending it to the calculation unit.

  As described above, with the image forming apparatus according to the present invention, it is possible to further reduce the power consumption of the apparatus without hindering the determination of the power-on state. It is possible to determine whether to turn on the power after the power is stopped or to return from the power saving state, and it is possible to display an image corresponding to the start factor on the display means when the power supply is started.

  Hereinafter, a case where the present invention is applied to a copying machine will be described as an example. FIG. 1 is a longitudinal sectional view schematically showing a main part structure of a copying machine according to the present invention. As shown in FIG. 1, a copying machine 1 according to the present embodiment includes a document transport unit 11 that automatically transports a document, and a document capture unit 12 that captures a document transported from the document transport unit 11 and generates image data. An operation display unit 13 including an operation unit (such as a numeric keypad or a touch panel) and a display unit (such as a liquid crystal display), and an image forming unit 14 (printing including a printer head or a photosensitive drum) that outputs an image to paper based on the image data A fixing unit 142 that fixes the image output obtained by the printing unit 141 to a sheet), a sheet feeding unit 15 that feeds the image forming unit 14, and an image output by the image forming unit 14. And a paper discharge unit 16 that serves as a paper discharge destination for the discharged paper.

  The paper feed unit 15 includes a plurality of (three in this embodiment) paper storage units 151 serving as a paper supply source to the image forming unit 14, and a common paper transport from each paper storage unit 151 to the image forming unit 14. And a sheet conveyance unit 152 serving as a path.

  Next, the document copying operation in the copying machine 1 configured as described above will be described. In the document copying operation in the copying machine 1, first, a document is transported from the document transport unit 11 to the document capture unit 12, and the document capture unit 12 captures the document (generates image data). The generated image data is temporarily stored in a memory unit (not shown), read again, and sent to the image forming unit 14. Thereafter, the image forming unit 14 performs an image forming process and a fixing process on the paper based on the input image data.

  Note that the copying machine 1 according to the present embodiment is configured such that when the power supply to the operation display control unit on the operation display substrate that controls the liquid crystal display and the return key is stopped, the power supply start factor is the power supply It has a feature in the means for determining whether the power is turned on from the stop state or the return from the power saving state. Therefore, in the following, with reference to FIG. 2, a detailed description will be given of the determination operation of the power supply start factor in the copying machine 1 of the present embodiment.

  FIG. 2 is a diagram showing circuit components related to the determination of the power supply start factor in the copying machine 1 according to the present invention. As shown in the figure, the copier 1 of the present embodiment includes a power source 21 that supplies power to each unit, a main board 22 that performs main control of the copier 1, and an operation display board that controls the operation display unit 13. 23.

  The operation display board 23 includes a liquid crystal display 24, an operation display control unit 25 for controlling the operation display board, a return key 26 for returning the output of the power source 21, a resistor R1, a resistor R2, a diode DV, Capacitor C1, discharge unit 30 that discharges capacitor C1, and a signal holding circuit that holds the stored voltage only for a predetermined period after discharge of capacitor C1 by discharge unit 30 and continues to send the stored voltage to operation display control unit 25 Part 29.

  The operation display control unit 25 includes an ASIC 251 and a CPU 252 that control the operation display substrate 23.

  The discharge unit 30 includes a resistor R3 and a transistor Tr, and the signal holding circuit unit 29 includes a select circuit 27 and a delay type flip-flop circuit 28.

  The output Vdd of the power source 21 is supplied to the main board 22, the liquid crystal display 24, and the operation display control unit 25. The output Vbak of the power source 21 is supplied to the main board 22 and one end of the return key 26. Note that when a predetermined condition such as when the non-operation state has elapsed for a predetermined time is satisfied and the state shifts to the power saving state, the output Vdd stops supplying power, but the output Vbak continues to supply power.

  The other end of the return key 26 to which the output Vbak is supplied is grounded via a resistor R1, and a KeyIn signal is input to the power source 21 from a connection node between the return key 26 and the resistor R1. When the KeyIn signal is input to the power source 21 in the power saving state, the output Vdd that has stopped outputting is restored, and power supply is resumed. The return key 26 is normally opened, and when the return key 26 is pressed, the return key 26 is closed and energized. The return key 26 may be closed by a signal (not shown) when the main board receives a predetermined instruction such as data reception from the external interface.

  One end of the resistor R2 is connected to a connection node between the return key 26 and the resistor R1, and the other end of the resistor R2 is connected to the anode of the diode DV. The cathode of the diode DV is grounded via the capacitor C1. One end of a resistor R3 and an input terminal 271 of the select circuit 27 are connected to a connection node between the cathode of the diode DV and the capacitor C1.

  The other end of the resistor R3 is connected to the collector of the transistor Tr1. The emitter of the transistor Tr1 is grounded. The output terminal 273 of the select circuit 27 is connected to the data input terminal 281 of the delay type flip-flop circuit 28. The signal Q 1 is input from the output terminal 282 of the delay type flip-flop circuit 28 to the input terminal 272 of the select circuit 27 and the CPU 252. The clock signal clk is input to the input terminal 283 of the delay type flip-flop circuit 28. The delay type flip-flop circuit is a flip-flop that outputs the input state of the input terminal 281 as the signal Q1 from the output terminal 282 when the clock signal clk changes from the L level to the H level.

  A reset signal resetn from the CPU 252 is input to the base of the transistor Tr 1 and the switching terminal 274 of the select circuit 27. A display screen control signal S 1 is sent from the operation display control unit 25 to the liquid crystal display 24.

  Next, in the copying machine 1 of the present embodiment, a determination operation for determining whether the power supply start factor to the operation display board 25 is from turning on the power from the power stop state or returning from the power saving state. Is described below.

  First, the determination of the power supply start factor is performed by the CPU 252 determining the signal Q1 output from the output terminal 282 of the delay type flip-flop circuit 28, as shown in FIG. When the signal Q1 is at L level, the CPU 252 determines that the start factor is due to power-on, and when the signal Q1 is at H level, the CPU 252 determines that the start factor is due to return from the power saving state.

  Next, the start factor determination operation at the start of power supply by turning on the power of the copying machine 1 will be described below. FIG. 3 is a chart of circuit signals for explaining the operation of determining the power supply start factor when the power is turned on after the power is stopped. As shown in FIGS. 2 and 3, when the power supply 21 is turned on, the output Vdd and the output Vbak are first output from the power supply 21. In the operation display board 23, the liquid crystal display 24, the ASIC 251 and the CPU 252 of the operation display control unit 25 are activated, and power is supplied to the end of the return key 26.

  Subsequently, the CPU 252 sends a reset signal resetn at L level 31 for a preset period to the base of the transistor Tr and the switching terminal 274 of the select circuit 28. At this time, since no charge is stored in the capacitor C1, the signal D1 indicating the stored voltage of the capacitor C1 indicates the L level 32. The signal D 1 at the L level 32 is input to the input terminal 271 of the select circuit 27 and then input from the output terminal 273 to the input terminal 281 of the delay type flip-flop circuit 28. When the clock signal clk changes from the L level to the H level 33, the delay type flip-flop circuit 28 inputs the L level signal which is the input state of the input terminal 281 and the output terminal 282 outputs the L level 34 signal Q1. The

  Thereafter, a reset signal resetn at H level 35 is sent from the CPU 252 to the base of the transistor Tr and the switching terminal 274 of the select circuit 28. At this time, the input of the selector circuit 27 is switched from the input terminal 271 to the input terminal 272. Further, the transistor Tr is turned on, and the capacitor C1 is grounded via the resistor R3. Note that since the electric charge is not stored in the capacitor C1, the signal D1 indicates the L level 36.

  Subsequently, the L level 37 signal Q 1 is input to the input terminal 272 of the switched selector circuit 27, and the L level signal is input from the output terminal 273 to the input terminal 281 of the delay type flip-flop circuit 28. When the clock signal clk changes from the L level to the H level 38, the delay type flip-flop circuit 28 inputs the L level signal that is the input state of the input terminal 281 and the output terminal 282 outputs the L level 39 signal Q1. The Since the input of the select circuit 27 is switched to the input terminal 272, the L-level 39 signal Q1 is input again to the select circuit 27, and the select circuit 27 and the delay type flip-flop circuit 28 output the L-level 39 signal Q1. Is repeated.

  Therefore, the CPU 252 reads the L-level signal Q1 for a predetermined time, and determines that the power supply start factor is power-on from the power-off state. Then, a control signal S1 for power-on image is sent from the operation display control unit 25 to the liquid crystal display 24, and an initial screen such as a logotype or a startup message is displayed on the liquid crystal display 24, for example.

  Next, the operation of determining the power supply start factor when the copier 1 is returned from the power saving state will be described below. FIG. 4 is a chart of circuit signals for explaining the operation of determining the power supply start factor when returning from the power saving state. As shown in FIGS. 2 and 4, in the power saving state, the power supply 21 stops the output Vdd and continues to supply the output Vbak. Therefore, the output Vbak is output only to one end of the return key 26 on the operation display board 23. Have been supplied.

  First, in order to return from the power saving state to the normal state, when the return key 26 is pressed, the return key 26 is energized and the KeyIn signal is input to the power source 21. The output Vdd of the power source 21 is restored, and the output Vdd is supplied to the liquid crystal display 24 and the CPU 252 and ASIC 251 of the operation display control unit 25. Then, a reset signal resetn at L level 41 is sent from the CPU 252. Since the return key 26 is energized, the capacitor C1 is charged by the output Vbak through the resistor R2 and the diode DV, and the signal D1 changes from the L level to the H level 42. Here, when the return key 26 is released, the charging of the capacitor C1 is stopped, but the charge stored in the capacitor C1 is grounded through the resistor R3 and the transistor Tr because the transistor Tr is off. The signal D1 is kept at the H level 42 without being discharged from the discharge path.

  Subsequently, the H level 42 signal D 1 is input to the input terminal 271 of the select circuit 27, and the H level signal is input from the output terminal 273 to the input terminal 281 of the delay type flip-flop circuit 28. When the clock signal clk changes from the L level to the H level 43, an H level signal is input to the input terminal 281 of the delay type flip-flop circuit 28, and an H level 44 signal Q1 is output from the output terminal 282.

  Subsequently, since the output Vdd of the power source 21 has been restored as described above, the output Vdd is supplied to the CPU 252. After the L level reset signal resetn is transmitted from the CPU 252 for a preset period, the H level 45 reset signal is output. resetn is sent out. Then, the input of the select circuit 27 is switched from the input terminal 271 to the input terminal 272, the signal Q1 of the H level 46 that is the input signal at this time is input to the input terminal 272, and the delay type flip-flop circuit 28 is output from the output terminal 273. An H level signal is input to the input terminal 281. When the clock signal clk changes from the L level to the H level 47, an H level signal is input to the input terminal 281 of the delay type flip-flop circuit 28, and an H level 48 signal Q1 is output from the output terminal Q.

  Further, since the reset signal resetn is at the H level 45, the transistor Tr is turned on, and the electric charge of the capacitor C1 is discharged through the discharge path grounded through the resistor R3 and the transistor Tr. It becomes level 49. However, since the input terminal 271 of the select circuit 27 has already been switched from the input terminal 271 to the input terminal 272, the H level 48 signal Q1 is again input to the input terminal 272 of the select circuit 27, and the select circuit 27 and the delay type flip-flop circuit 28. Thus, the output of the H level signal Q1 is repeated, and the H level 48 signal Q1 is maintained.

  Therefore, the CPU 252 reads the H level signal Q1 for a predetermined time, and determines that the power supply start factor is the return from the power saving state. Then, an image control signal S1 for returning from the power saving state is sent from the operation display control unit 25 to the liquid crystal display 24. For example, a screen immediately before the transition to the power saving state is displayed on the liquid crystal display 24.

  In addition, as shown in FIG. 2, even in the configuration in which the signal holding circuit unit 29 (that is, the select circuit 27 and the delay type flip-flop circuit 28) is removed, it is possible to determine the power supply start factor. As described above, since the electric charge is not held in the capacitor C1 when the power is turned on, the L-level signal D1 is input to the CPU 252. The CPU 252 reads the L-level signal D1 for a predetermined time, and determines that the power supply start factor is due to power-on. When returning from the power saving state, when the return key 26 is pressed, electric charge is stored in the capacitor C1, and the signal D1 becomes H level. The H level signal D1 is detected by the CPU 252 until the transistor Tr is turned on by the H level reset signal resetn and the electric charge stored in the capacitor C1 is discharged. The CPU 252 reads the H level signal D1 for a predetermined time, and determines that the power supply start factor is the return from the power saving state. As the return key is pressed, the reset signal resetn changes to the H level after instructing the L level for a reset period preset in the circuit. Usually, the L level reset signal resetn is instructed for several hundreds msec. Therefore, the time for which the capacitor C1 should hold the charge may be 1 sec.

  Even in the configuration in which the signal holding circuit unit 29 (that is, the select circuit 27 and the delay type flip-flop circuit 28) and the discharge unit 30 (that is, the transistor Tr and the resistor R3) are omitted, the determination of the power supply start factor is possible. Is possible. Since no charge is held in the capacitor C1, the L level signal D1 is detected by the CPU 252. The CPU 252 reads the L-level signal D1 for a predetermined time, and determines that the power supply start factor is due to power-on. When returning from the power saving state, electric charge is stored in the capacitor C 1, and an H level signal D 1 is input to the CPU 252. The CPU 252 reads the H level signal D1 for a predetermined time, and determines that the power supply start factor is the return from the power saving state. In the determination of the start factor when the power is turned on, since the transistor Tr is not included, the CPU 252 recognizes that the signal D1 is at the H level due to the residual charge of the capacitor C1, and the power saving state is changed. There is a possibility of misjudgment as a return. In this case, in the determination of the signal level of the signal D1 by the CPU 252, the determination threshold value of the signal level of the CPU 252 may be adjusted to prevent erroneous determination to H level.

  The present invention can be widely applied to image forming apparatuses such as printers and facsimiles in addition to copying machines. The power supply starting factor is that power is turned on from a power-off state or a part of power is supplied. This is a useful technique with respect to a circuit that can determine whether it is a return from a stopped power saving state.

These are the longitudinal cross-sectional views which show typically the principal part structure of the copying machine which concerns on this invention. These are figures which show the circuit structure part related to the start factor determination of the electric power supply in the copying machine 1 which concerns on this invention. These are the chart figures of a circuit signal explaining the determination operation | movement of the start factor of the power supply at the time of power activation from a power stop state. These are the circuit signal charts explaining the determination operation | movement of the start factor of the electric power supply at the time of a return from a power saving state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copier 11 Document conveying part 12 Document taking-in part 13 Operation display part 14 Image forming part 141 Printing part 142 Fixing part 15 Paper feed part 151 Paper storage part 152 Paper conveying part 16 Paper discharge part 21 Power supply 22 Main board 23 Operation display Substrate 24 Liquid crystal display 25 Operation display controller 251 Application specific integrated circuit (ASIC)
252 Central processing unit (CPU)
26 Return key 27 Select circuit 28 Delay type flip-flop circuit

Claims (3)

An arithmetic unit that performs predetermined signal processing and a unit that controls power supply to the arithmetic unit, and temporarily stops the power supply under a predetermined condition, and supplies the power in response to a predetermined return instruction In an image forming apparatus comprising: a power supply unit having a function of resuming operation; and a capacitor unit that accumulates electric charges when the return instruction is issued.
The image forming apparatus according to claim 1, wherein when the power is supplied from the power supply unit, the arithmetic unit determines whether the power supply is initially turned on or returned from a temporarily stopped state according to a storage voltage of the capacity unit.   The image forming apparatus according to claim 1, further comprising a unit that discharges the capacitor unit based on an instruction from the arithmetic unit that receives power supply from the power source unit.   3. The image forming apparatus according to claim 1, further comprising means for holding the stored voltage of the capacity unit for a predetermined time after the discharge and continuing to send the stored voltage to the calculation unit.

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