JP2008080531A - Control unit initialization apparatus and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To initialize a control unit surely when a power switch is turned off. <P>SOLUTION: The initialization apparatus 91 comprises a one-shot multivibrator circuit 911 delivering a signal S2 (= off state: Low level) indicating the suspension of power supply from a commercial power supply to a power supply unit 7 when a zero-cross signal S1 from a zero-cross signal generation circuit 71 is not inputted for a predetermined period or longer, and transistors TR1 and TR2 for grounding the DC power supply line of 5V through a load resistor R2 when the signal S2 of the one-shot multivibrator circuit 911 turns into an off state (= Low level). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  According to the present invention, a predetermined DC voltage set in advance is applied from a power supply unit communicatively connected to a commercial power supply via a power switch operable from the outside, and control for initializing a control unit having a CPU is performed. The present invention relates to a unit initialization apparatus and electronic equipment. In particular, the present invention relates to a copying machine, a printer, a facsimile machine, an Internet facsimile machine, which is an apparatus for forming an image on recording paper, and a multifunction machine having any one of these functions.

  When an abnormality (jam, hang-up, etc.) occurs in an image forming apparatus such as a copying machine or a printer, the user turns off the power switch and then turns on the power switch for the purpose of restoring the image forming apparatus. An operation may be performed.

On the other hand, the image forming apparatus has a power supply unit for generating a DC voltage (for example, 5V, 24V, etc.) used inside the image forming apparatus from a commercial power supply. In order to suppress load fluctuations or reduce noise, capacitive loads made of electrolytic capacitors or the like are disposed at various locations on a substrate such as a control unit (see Patent Document 1).
JP 2006-201384 A

  Therefore, even when the power switch is turned off, the DC voltage supplied to the control unit provided in the image forming apparatus gradually decreases due to the influence of the capacitive load and the stray capacitance. Therefore, even when the user turns off the power switch for the purpose of returning from the abnormal state and then turns it on, the control unit holds the abnormal state if the interval between the OFF operation and the ON operation is short. May remain. In this case, the user repeats the above operation (operation to turn on after turning off the power switch), which is complicated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control unit initialization apparatus and an electronic device that can reliably initialize a control unit when a power switch is turned off. It is said.

  In order to achieve the above object, a control unit initialization apparatus according to claim 1 is a predetermined DC voltage preset from a power supply unit connected to a commercial power supply through a power switch operable from outside. Is a control unit initialization device that initializes a control unit having a CPU, and that detects that power supply from a commercial power supply to the power supply unit is stopped via the power switch It is characterized by comprising: a detecting means; and a reset signal generating means for outputting a reset signal to the CPU when the operation detecting means detects that the supply of power is stopped.

  The control unit initialization apparatus according to claim 2 is configured such that a predetermined DC voltage set in advance is applied from a power supply unit connected to a commercial power supply through a power switch operable from the outside, and a CPU is connected to the CPU. A control unit initialization device for initializing a control unit having an operation detecting means for detecting that power supply from a commercial power supply to the power supply unit is stopped via the power switch, and the operation detection And a grounding means for grounding a power supply line that is a wiring for supplying the predetermined DC voltage to the control unit when it is detected that the supply of power is stopped by the means.

  The control unit initialization apparatus according to claim 3 is the control unit initialization apparatus according to claim 1 or 2, wherein the power supply unit corresponds to a zero cross point of a voltage supplied from a commercial power supply. A zero-cross signal generating means for generating a zero-cross signal that is a pulse signal, and the operation detecting means detects that the supply of power from a commercial power source to the power supply unit is stopped based on the zero-cross signal. It is a feature.

  A control unit initialization apparatus according to a fourth aspect is the control unit initialization apparatus according to the third aspect, wherein the operation detection unit is configured to input the zero-cross signal for a predetermined period or longer. A one-shot multi-circuit that outputs a signal indicating that power supply from a commercial power supply to the power supply unit has been stopped is provided.

  The control unit initialization apparatus according to claim 5 is the control unit initialization apparatus according to claim 1, wherein the control unit includes a reset IC, and the reset signal generation unit is operated by the operation detection unit. When it is detected that power supply has been stopped, a reset signal is output from the reset signal output terminal of the reset IC.

  The control unit initialization apparatus according to claim 6 is the control unit initialization apparatus according to claim 5, wherein the reset signal generation unit detects that the supply of power is stopped by the operation detection unit. In this case, a transistor for outputting a reset signal from a reset signal output terminal of the reset IC via a pull-up resistor is provided.

  The control unit initialization device according to claim 7 is the control unit initialization device according to claim 6, wherein the reset signal generation means is detected that the supply of power is stopped by the operation detection means. A command circuit for generating a command signal for outputting a reset signal, a command signal from the command circuit, and a reset signal from the reset IC are output to the CPU. On the other hand, a logic circuit that outputs a reset signal is provided.

  The control unit initialization apparatus according to claim 8 is the control unit initialization apparatus according to claim 2, wherein the grounding means detects that the supply of power has been stopped by the operation detection means. A transistor that is turned on; and a load resistor having one end connected to the transistor and the other end connected to the power supply line, and the one end of the load resistor when the transistor is turned on. Is configured to be grounded.

The electronic apparatus according to claim 9, a fixing unit that fixes a toner image on a recording sheet;
A power supply unit connected to a commercial power supply through a power switch operable from the outside so as to be energized, a predetermined DC voltage set in advance, a predetermined DC voltage applied from the power supply unit, and the fixing A control unit having a CPU for controlling the operation of the unit, and a control unit initialization apparatus according to any one of claims 1 to 8 are provided.

  According to the control unit initialization apparatus of the first aspect, when it is detected that the supply of power from the commercial power supply is stopped (for example, when the power switch is turned off), the control unit initialization apparatus Since the reset signal is output, the reset process is executed by the CPU, and the control unit can be reliably initialized.

  According to the control unit initialization apparatus of claim 2, when it is detected that the supply of electric power from the commercial power supply is stopped (for example, when the power switch is turned off), the predetermined DC voltage is supplied from the power supply unit. Since the power supply line that is the wiring for supplying the control unit to the control unit is grounded, the DC voltage supplied to the control unit instantaneously becomes “0”, so that the control unit can be initialized reliably.

  According to the control unit initialization apparatus of the third aspect, since it is detected that the supply of power from the commercial power supply to the power supply unit is stopped based on the zero cross signal, the power from the commercial power supply to the power supply unit is detected. It is possible to accurately detect that the supply of is stopped.

  Further, in the image forming apparatus such as a printer, since the zero cross signal is used to control the fixing temperature, the supply of power from the commercial power supply to the power supply unit is stopped with a simple configuration, and It can be detected accurately.

  According to the control unit initialization apparatus of claim 4, the supply of power from the commercial power supply to the power supply unit is stopped by the one-shot multi-circuit when the zero-cross signal is not input for a predetermined period or longer. Since a signal to that effect is output, it is possible to accurately detect the supply of power from the commercial power supply to the power supply unit with a simple configuration.

  According to the control unit initialization apparatus of the fifth aspect, when it is detected that the supply of power from the commercial power supply is stopped, the reset signal is output from the reset signal output terminal of the reset IC. The reset signal can be output accurately with the configuration.

  According to the control unit initialization apparatus of the sixth aspect, when it is detected that the supply of electric power from the commercial power supply is stopped, the transistor causes the reset IC to output the reset signal via the pull-up resistor. Since the reset signal is output, the reset signal can be output accurately with a simpler configuration.

  According to the control unit initialization apparatus of claim 7, a command signal from a command circuit that generates a command signal to output a reset signal when it is detected that the supply of power from the commercial power supply is stopped, And when at least one of the reset signals from the reset IC is output, the reset signal is output to the CPU by the logic circuit, so the reset signal is output more accurately and with a simpler configuration. can do.

  According to the control unit initialization apparatus of claim 8, when it is detected that the supply of power is stopped, the transistor is turned on, and the other end of the load resistor connected to the power supply line is grounded. Therefore, the control unit can be initialized with a simpler configuration and with certainty.

  According to the electronic device according to claim 9, since the control unit initialization device according to any one of claims 1 to 8 is provided, an electronic device capable of reliably initializing the control unit is realized. can do.

  Hereinafter, an example of an electronic apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram (side view) showing an example of a schematic configuration of an electronic apparatus according to the present invention. Here, the case where the electronic device is a monochrome printer will be described. However, the electronic device may be a color printer, or another image forming apparatus that forms an image on a recording sheet by transferring toner (for example, Facsimile, copier, etc.). Further, the electronic device may be an electronic device other than the image forming apparatus (for example, a DVD (Digital Versatile Disc) player). As shown in FIG. 1, the printer 100 includes a display unit 1, an operation unit 2, a developing unit 3, a photosensitive unit 4, a laser scanning unit 5, and a fixing unit 6. Further, the printer 100 is provided with a power supply unit 7, a control unit 8, and a control unit initialization device 9 at appropriate positions (see FIG. 3).

  The display unit 1 displays various information so as to be visible from the outside. Specifically, the display unit 1 includes, for example, an LCD (Liquid Crystal Display) and displays various operation information, setting information, guidance information, and the like. To do.

  The operation unit 2 accepts operations from the outside. Specifically, for example, the operation unit 2 includes various operation buttons, a touch panel formed integrally with the LCD disposed in the display unit 1, and the like. The operation of is accepted.

  The developing unit 3 attaches toner to an electrostatic latent image formed on the surface of the photosensitive drum by a laser beam from the laser scanning unit 5 and corresponding to image data input from an external device (for example, a personal computer). Thus, a toner image is formed.

  The photosensitive unit 4 includes a photosensitive drum. The surface of the photosensitive drum is first charged substantially uniformly by a charging roller, and then toner is attached to the electrostatic latent image corresponding to the original image by the developing unit 3. Thus, a toner image is formed, and the toner image is further transferred onto a recording sheet by a transfer roller.

  The fixing unit 6 includes a heating roller (= fixing roller) 61 and fixes the toner image transferred onto the recording paper by the photosensitive unit 4 onto the recording paper. Further, the fixing roller 61 is heated by a heater such as a halogen lamp (not shown), and for example, the surface temperature of the fixing roller 61 is controlled to be about 180 ° C.

  In the fixing unit 6, the power supplied to the heater is accurately controlled to maintain the surface temperature of the fixing roller 61 at the fixing temperature (or standby temperature). Here, a phase control method and a half-wave control method are known as heater control methods.

  FIG. 2 is a waveform diagram of a voltage (or current) generated by the phase control method and the half-wave control method when the duty ratio is 50%. (A) is a waveform diagram of a voltage (or current) generated by the phase control method, and (b) is a waveform diagram of a voltage (or current) generated by the half-wave control method. When the phase control method or the half-wave control method is applied, the surface temperature of the fixing roller 61 can be controlled by controlling the duty ratio of the supplied power.

  For example, in the phase control method, a zero-cross signal that is a pulse signal corresponding to a zero-cross point of a voltage supplied from a commercial power supply is used to control the duty ratio. That is, the duty ratio is turned on when a predetermined time (for example, half the time of a half cycle) has elapsed from the time when the zero-cross signal is detected and turned off when the zero-cross signal is detected, so that a desired duty ratio (here, 50% ) Is obtained.

  FIG. 3 is a block diagram showing an example of a connection state of the control unit initialization apparatus according to the present invention. As shown to (a), the control unit initialization apparatus (henceforth initialization apparatus) 9 is connected so that communication with the power supply unit 7 and the control unit 8 is possible. The power supply unit 7 includes a zero-cross signal generation circuit 71, and uses predetermined AC voltages (here, 5V and 24V) set using an AC voltage supplied from a commercial power supply (for example, 100V, 60Hz). Is generated. A power switch (not shown) is interposed between the power supply unit 7 and the commercial power supply.

  The zero-cross signal generation circuit 71 generates a zero-cross signal that is a pulse signal corresponding to a zero-cross point (a point at which the voltage value is “0”) of the voltage supplied from the commercial power supply (see FIG. 5A). ). The zero cross signal is, for example, a pulse signal having a predetermined width around the zero cross point. The zero-cross signal generation circuit 71 includes, for example, a full-wave rectifier circuit and a photocoupler.

  The control unit 8 controls the overall operation of the printer 100, and includes a controller board 81 and an engine board 82 as shown in FIG. The controller board 81 executes image processing and the like, and outputs command information to the engine board 82, and includes a CPU (Central Processing Unit) 811.

  The engine board 82 includes a CPU 821 and a reset IC 822, controls recording paper conveyance, and the like, and operates based on a command from the CPU 811 of the controller board 81. The reset IC 822 outputs a reset signal to the CPU 821 and the CPU 811. Specifically, the output terminal of the reset IC 822 is an open collector, and when a reset signal is output, the output terminal is in an OFF state (= Low level).

  Further, a DC voltage of 5V is applied from the power supply unit 7 to the controller board 81, and DC voltages of 5V and 24 are applied from the power supply unit 7 to the engine board 82. In addition, a capacitive load is connected to the power supply line of DC voltage (5V, 24V) supplied from the power supply unit 7 to the controller board 81 and the engine board 82 for the purpose of suppressing load fluctuations or reducing noise. Has been.

  FIG. 4 is a configuration diagram showing the first embodiment and the second embodiment of the initialization device 9. The initialization device 91 according to the first embodiment includes a one-shot multi-circuit 911, a transistor TR1, and a transistor TR2, as shown in FIG. The initialization device 92 according to the second embodiment includes a one-shot multi-circuit 921 and a transistor TR3 as shown in FIG.

  One-shot multi-circuits 911 and 921 (corresponding to the operation detecting means) generate power from the commercial power supply to the power supply unit 7 when the zero-cross signal S1 from the zero-cross signal generation circuit 71 is not input for a predetermined period or longer. A signal indicating that the supply has been stopped is output. The operation of the one-shot multicircuits 911 and 921 will be specifically described with reference to FIG.

  FIG. 5 is a timing chart showing an example of the operation of the one-shot multicircuits 911 and 921. (A) is a timing chart showing the zero-cross signal S1 generated by the zero-cross signal generation circuit 71, and (b) is a timing chart showing the output signal S2 of the one-shot multi-circuits 911 and 921.

  The upper side of (a) is the voltage waveform of the commercial power supply, and the lower side is the waveform of the zero cross signal S1. As shown to (a), the zero cross signal S1 is a pulse signal which has a predetermined width | variety centering | focusing on the point (= zero cross point) where the voltage of a commercial power source is zero. In (b), the voltage waveform of the commercial power supply, the zero cross signal S1, and the output signal S2 of the one-shot multicircuits 911 and 921 are displayed in order from the top.

  As shown in (b), when the power switch is turned off at time T0 and supply of commercial power to the power supply unit 7 is stopped, the zero cross signal S1 by the zero cross signal generation circuit 71 after time T0 is stopped. The output signal S2 of the one-shot multi-circuits 911 and 921 is in an OFF state after a predetermined time (here, commercial power supply half cycle ΔT × 4 = 1/60 × 1/2 × 4 sec) after the zero-cross signal S1 is stopped. = Low level).

  Returning to FIG. 4 again, the configuration of the initialization apparatus 91 according to the first embodiment will be described. The transistor TR1 (corresponding to a part of the grounding means) is an NPN type transistor, and the output signal S2 of the one-shot multicircuit 911 is supplied to the base, the emitter is grounded, and the collector is connected via the pull-up resistor R1. It is connected to a 5V DC power line. Further, the transistor TR2 (corresponding to a part of the grounding means) is an NPN type transistor, the collector of the transistor TR1 is connected to the base, the emitter is grounded, and the collector is a DC power supply of 5V via the load resistor R2. Connected to the line.

  Next, the operation of the initialization device 91 according to the first embodiment will be described. When the output signal S2 of the one-shot multicircuit 911 is in an OFF state (= Low level), the transistor TR1 is in an OFF state, and the collector voltage of the transistor TR1 is approximately 5V. As a result, the transistor TR2 is turned on, and the 5V DC power supply line is grounded via the load resistor R2. Therefore, the charge of the capacitive load (and stray capacitance) connected to the 5V DC power supply line shown in FIG. 3B flows out through the load resistor R2, and the voltage of the 5V DC power supply line quickly becomes zero. It is.

  As shown in FIG. 4 (b), the initialization device 92 according to the second embodiment has a transistor TR3 instead of the transistors TR1 and TR2 of the initialization device 91 according to the first embodiment shown in FIG. 4 (a). Are connected. The transistor TR3 (corresponding to the grounding means) is a PNP type transistor, and the output signal S2 of the one-shot multicircuit 921 is supplied to the base, the emitter is grounded, and the collector is a DC power supply of 5V via the load resistor R3. Connected to the line.

  Next, the operation of the initialization device 92 according to the second embodiment will be described. When the output signal S2 of the one-shot multi-circuit 911 is turned off (= low level), the transistor TR3 is turned on, and the 5V DC power supply line is grounded via the load resistor R3. Therefore, the charge of the capacitive load (and stray capacitance) connected to the 5V DC power supply line shown in FIG. 3B flows out through the load resistor R3, and the voltage of the 5V DC power supply line quickly becomes zero. It is.

  FIG. 6 is a configuration diagram showing the third embodiment and the fourth embodiment of the initialization apparatus 9. The initialization device 93 according to the third embodiment includes a one-shot multi-circuit 931, a transistor TR4, and a transistor TR5, as shown in FIG. The initialization apparatus 94 according to the fourth embodiment includes a one-shot multi circuit 941, a NOT circuit 942, and an AND circuit 943, as shown in FIG. The one-shot multicircuits 931 and 941 (corresponding to the operation detecting means) are the same as the one-shot multicircuit 911 of the initialization apparatus 91 according to the first embodiment, and thus description thereof is omitted.

  As shown in FIG. 6 (a), the initialization device 93 according to the third embodiment has a transistor TR4 instead of the transistors TR1 and TR2 of the initialization device 91 according to the first embodiment shown in FIG. 4 (a). , TR5 is connected. The transistor TR4 (corresponding to a part of the reset signal generating means) is an NPN type transistor, and the output signal S2 of the one-shot multicircuit 931 is supplied to the base, the emitter is grounded, and the collector is the pull-up resistor R4. Via a 5V DC power line. The transistor TR5 (corresponding to a part of the reset signal generating means) is an NPN type transistor, and the collector of the transistor TR4 is connected to the base, the emitter is grounded, and the collector is 5V through the pull-up resistor R5. Are connected to the output terminal of the reset IC 822 disposed on the engine board 82 shown in FIG. 3B.

  Next, the operation of the initialization device 93 according to the third embodiment will be described. When the output signal S2 of the one-shot multi-circuit 931 is in an OFF state (= Low level), the transistor TR4 is in an OFF state, and the collector voltage of the transistor TR4 is approximately 5V. As a result, the transistor TR5 is turned on, the reset signal S3 is output from the output terminal of the reset IC 822 (OFF state = Low level), and the CPU 821 and the CPU 811 (see FIG. 3B) are reset. .

  As shown in FIG. 6B, the initialization device 94 according to the fourth embodiment is replaced with a NOT circuit in place of the transistors TR4 and TR5 of the initialization device 93 according to the third embodiment shown in FIG. 942 and an AND circuit 943 are connected. However, the one-shot multi-circuit 941 (corresponding to the operation detecting means) is obtained by inverting the output of the one-shot multi-circuit 911 of the initialization device 91 according to the first embodiment. That is, the one-shot multi-circuit 941 stops the zero-cross signal S1 by the zero-cross signal generation circuit 71 after the time T0 when the power switch is turned off at the time T0 and the supply of the commercial power to the power supply unit 7 is stopped. The output signal S2 ′ of the one-shot multi-circuit 941 is in an ON state (in this case, a commercial power supply half cycle ΔT × 4 = 1/60 × 1/2 × 4 sec) after the zero-cross signal S1 is stopped. = High level) (see FIG. 5B).

  The NOT circuit 942 (corresponding to a part of the command circuit and the reset signal generating means) inverts the signal, and the output signal S2 ′ of the one-shot multicircuit 941 is input, and the output signal S2 is input to the AND circuit 943. A signal with 'inverted' is output. The AND circuit 943 (corresponding to a part of the logic circuit and the reset signal generation means) outputs an ON signal (= High level) when both input signals are in the ON state (= High level). The output of the reset IC 822 and the output signal of the NOT circuit 942 arranged on the engine board 82 shown in FIG. 3B are input, and the reset signal S4 is output to the CPU 821 and the CPU 811. is there.

  In addition, a pull-up resistor R6 is connected to the output terminal of the output terminal of the reset IC 822. Therefore, when the reset IC 822 does not output a reset signal, an output terminal thereof is an open collector open collector, so that it is turned on (= High level) by the pull-up resistor R6.

  Next, the operation of the initialization device 94 according to the fourth embodiment will be described. When the zero-cross signal S1 is stopped and the output signal S2 ′ of the one-shot multi-circuit 941 is turned on (= High level) a predetermined time after the zero-cross signal S1 is stopped, the output signal S2 ′ of the NOT circuit 942 is turned off. (= Low level). Therefore, the output of the AND circuit 943 is turned off (= Low level), and the reset signal S4 is output to the CPU 821 and the CPU 811.

  Thus, according to the initialization apparatus 93 of the third embodiment or the initialization apparatus 94 of the fourth embodiment, when it is detected that the supply of power from the commercial power supply is stopped (for example, the power switch is turned off). In this case, since a reset signal is output to the CPUs 811 and 812 of the control unit 8, a reset process is executed by the CPUs 811 and 821, and the control unit can be reliably initialized.

  Further, according to the initialization device 91 of the first embodiment or the initialization device 92 of the second embodiment, when it is detected that the supply of power from the commercial power supply is stopped (for example, when the power switch is turned off) ), Since the power supply line, which is a wiring for supplying a predetermined DC voltage from the power supply unit 7 to the control unit 8, is grounded, the DC voltage supplied to the control unit 8 instantaneously becomes “0”. The control unit 8 can be initialized.

  Furthermore, according to the initialization devices 91 to 94 of the first to fourth embodiments, since it is detected that the supply of power from the commercial power source to the power supply unit 7 is stopped based on the zero cross signal S1, It can be accurately detected that the supply of power from the power supply to the power supply unit 7 is stopped.

  In addition, according to the initialization devices 91 to 94 of the first to fourth embodiments, since the printer 100 uses the zero cross signal S1 to control the fixing temperature, the commercial power supply to the power supply unit 7 is used. It is possible to accurately detect that the supply of power has been stopped with a simple configuration.

  Further, according to the initialization devices 91 to 94 of the first to fourth embodiments, when the zero-cross signal S1 is not input for a predetermined period or longer by the one-shot multicircuits 911 to 941, the power supply unit is switched from the commercial power supply. Since the signals S2 and S2 ′ indicating that the supply of power to the power supply 7 has been stopped are output, the supply of power from the commercial power supply to the power supply unit 7 has been stopped with a simple configuration and accurately. Can be detected.

  Further, according to the initialization device 93 of the third embodiment or the initialization device 94 of the fourth embodiment, when it is detected that the supply of power from the commercial power supply is stopped, the reset signal output terminal of the reset IC 822 is used. Since the reset signals S3 and S4 are output, the reset signal can be output accurately with a simple configuration.

  In addition, according to the initialization device 93 of the third embodiment, when it is detected that the supply of power from the commercial power supply is stopped, the transistors TR4 and TR5 pull up from the reset signal output terminal of the reset IC 822. Since the reset signal S3 is output via the resistor R5, the reset signal can be accurately output with a simpler configuration.

  Further, according to the initialization device 94 of the fourth embodiment, a command signal from the NOT circuit 942 that generates a command signal for outputting a reset signal when it is detected that the supply of power from the commercial power supply is stopped. And when at least one of the reset signals from the reset IC 822 is output, the AND circuit 943 outputs the reset signal S4 to the CPUs 811, 821, so that the configuration is simpler and more accurate. Can output a reset signal.

  Further, according to the initialization device 91 of the first embodiment or the initialization device 92 of the second embodiment, when the supply of power is detected to be stopped, the transistors TR2 and TR3 are turned on, and the other end is Since one end of the load resistors R2 and R3 connected to the power supply line is grounded, the control unit 8 can be initialized with a simpler configuration and more reliably.

The present invention can also be applied to the following forms.
(A) In the first to fourth embodiments, the case where the electronic apparatus is the printer 100 has been described. However, the electronic apparatus may be another image forming apparatus, or the electronic apparatus may be other than the image forming apparatus. The electronic device (for example, a DVD player) may be used.

  (B) Although the case where the printer 100 includes the two CPUs 811 and 821 has been described in the first to fourth embodiments, the printer 100 may include one CPU.

  (C) In the first to fourth embodiments, the case where the operation detection unit is composed of the one-shot multi-circuits 911 to 941 and the like has been described, but when it is detected that the supply of power from the commercial power source is stopped, It may be configured by other circuits that output a signal to that effect.

  (D) In the first and second embodiments, the case where the grounding means includes the transistors TR1 to TR3 and the like has been described. However, when it is detected that the supply of power from the commercial power supply is stopped, the DC voltage is controlled by the control unit. 7 may be configured by another circuit for grounding a power supply line that is a wiring to be supplied to the circuit 7.

  (E) In the third and fourth embodiments, the case where the reset signal generating means is composed of the transistors TR4, TR5, the NOT circuit 942, the AND circuit 943, etc. has been described, but it is detected that the supply of power from the commercial power supply is stopped. In this case, the CPU 811 and 821 may be configured by other circuits that output a reset signal.

These are the schematic diagrams (side view) which show an example of schematic structure of the printer which concerns on this invention. These are waveform diagrams of the voltage (or current) generated by the phase control method and the half-wave control method when the duty ratio is 50%. These are the block diagrams which show an example of the connection state of the control unit initialization apparatus which concerns on this invention. These are the block diagrams which show 1st Embodiment and 2nd Embodiment of an initialization apparatus. These are timing charts showing an example of the operation of the one-shot multi-circuit. These are the block diagrams which show 3rd Embodiment and 4th Embodiment of an initialization apparatus.

Explanation of symbols

100 Printer (electronic equipment)
6 Fixing Unit 61 Fixing Roller 7 Power Supply Unit 71 Zero Cross Signal Generation Circuit 8 Control Unit 81 Controller Board 811 CPU
82 Engine board 821 CPU
822 Reset IC
91-94 Initializing device (control unit initializing device)
911-914 One-shot multi-circuit (operation detection means)
TR1 to TR3 transistors (grounding means)
TR4, TR5 transistors (part of reset signal generation means)
942 NOT circuit (part of reset signal generation means)
943 AND circuit (part of reset signal generation means)

Claims (9)

A control unit initialization device that applies a predetermined DC voltage set in advance from a power supply unit connected to a commercial power supply through a power switch operable from the outside and initializes a control unit having a CPU Because
Operation detecting means for detecting that the supply of power from a commercial power supply to the power supply unit is stopped via the power switch;
A reset signal generating means for outputting a reset signal to the CPU when the operation detecting means detects that the supply of power is stopped;
A control unit initialization apparatus comprising: A control unit initialization device that applies a predetermined DC voltage set in advance from a power supply unit connected to a commercial power supply through a power switch operable from the outside and initializes a control unit having a CPU Because
Operation detecting means for detecting that the supply of power from a commercial power supply to the power supply unit is stopped via the power switch;
A grounding means for grounding a power supply line that is a wiring for supplying the predetermined DC voltage to the control unit when the operation detecting means detects that the supply of power is stopped;
A control unit initialization apparatus comprising: The power supply unit includes zero-cross signal generation means for generating a zero-cross signal that is a pulse signal corresponding to a zero-cross point of a voltage supplied from a commercial power supply,
3. The control unit initial stage according to claim 1, wherein the operation detecting unit detects that the supply of power from a commercial power source to the power source unit is stopped based on the zero-cross signal. Device.   The operation detection means includes a one-shot multi-circuit that outputs a signal indicating that the supply of power from a commercial power supply to the power supply unit is stopped when the zero-cross signal is not input for a predetermined period or longer. The control unit initialization apparatus according to claim 3, wherein: The control unit includes a reset IC,
The said reset signal generation means outputs a reset signal from the reset signal output terminal of the said reset IC, when it is detected by the said operation detection means that supply of electric power was stopped. Control unit initialization device.   The reset signal generation unit includes a transistor that outputs a reset signal from a reset signal output terminal of the reset IC via a pull-up resistor when the operation detection unit detects that power supply is stopped. The control unit initialization apparatus according to claim 5, wherein: The reset signal generation means generates a command signal for outputting a reset signal when the operation detection means detects that the supply of power has been stopped, and
A logic circuit that outputs a reset signal to the CPU when at least one of a command signal from the command circuit and a reset signal from the reset IC is output;
The control unit initialization apparatus according to claim 6, further comprising: The grounding means includes a transistor that is turned on when power supply is detected to be stopped by the operation detecting means, a load having one end connected to the transistor and the other end connected to the power supply line. With resistance,
3. The control unit initialization apparatus according to claim 2, wherein when the transistor is turned on, the one end of the load resistance is configured to be grounded. A fixing unit for fixing a toner image on recording paper;
A power supply unit that is connected to a commercial power supply through a power switch that can be operated from the outside so as to be energized, and generates a predetermined DC voltage that is set in advance,
A control unit having a CPU that controls the operation of the fixing unit while a predetermined DC voltage is applied from the power supply unit;
A control unit initialization apparatus according to any one of claims 1 to 8,
An electronic device comprising:

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