JP4244918B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a facsimile, or a multifunction machine having these functions, which forms an image on a recording medium based on image data obtained by reading an image of a document.

  2. Description of the Related Art Conventionally, an image forming apparatus that forms an image based on image data obtained by reading a document image or receiving data includes various components that are operated by electric power, such as a motor that drives a paper conveyance system. For example, when a document image is read by a scanner or the like, a paper transport system of an automatic document feeder (ADF) driven by a stepping motor or the like transports a document to a document reading unit, a paper feed cassette or a large-volume paper feed device ( LCT) operates to convey a sheet of a desired size to the image forming unit.

The document image data read by the scanner is subjected to image processing such as γ correction, scaling, spatial filter, and image compression. The original image data subjected to the image processing is transferred to the image forming means. The image forming unit forms an image on a recording medium such as a predetermined sheet based on the document image data. At this time, an electrostatic latent image based on the document image data is formed on the drum uniformly charged by the charging unit by the laser beam output unit and the polygon mirror that scans the laser beam. Development is performed by the developing unit to be supplied. The image formed on the drum through such charging, latent image formation, and development is transferred to a recording medium by a transfer unit. The image transferred onto the recording medium is thermally fixed by a fixing unit. As a result, a document image can be printed. The printed recording medium is conveyed by a paper discharge conveyance system, and is post-processed by a finisher (FNS) as desired. In the above operation, it is necessary to supply power to various motors, heaters of fixing means, and the like, and power is supplied through a plurality of power supply blocks in consideration of the configuration contents of each unit and necessary voltages.
As described above, the image forming apparatus consumes a large amount of power in various devices. For this reason, when the image formation is not being performed, if the stop time becomes longer, the temperature of the fixing unit is lowered or the display unit is turned off to shift to a power saving (low power) mode in which power consumption is reduced. Is widely adopted (see, for example, Patent Document 1).

Further, when returning from the power saving mode, there is a problem that the power supply voltage tends to become unstable if the return operation is performed in a short time. When multiple loads are turned on at the same time, a switch is provided on each of the input side and output side of the power supply, and when the input side switch is turned on, the output side switch is turned on. A means for delaying has been proposed (for example, Patent Document 2).
JP 2002-9992 A JP-A-9-149552

In the power saving mode described above, the operation of the image forming apparatus is monitored by the operation of the system control unit that controls the entire image forming apparatus. For example, the button that cancels the power saving mode in the operation unit or the network is passed. The normal operation state is restored from the power saving mode by receiving data or the like.
However, in the above power saving mode, it is necessary that the system control unit is always operating, and the CPU incorporated in the system control unit always consumes power. The power consumption rate occupied by the CPU in the system control unit is normally the largest, and therefore the power saving of the entire image forming apparatus is not sufficient even in the power saving mode, and further power saving is desired.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an image forming apparatus that further enables power saving by providing a power saving mode in which power consumption is further reduced. .

That is, among the image forming apparatuses of the present invention, the image forming apparatus according to claim 1 has a plurality of power supply blocks for controlling or driving each component of the image forming apparatus, and one of the power supply blocks includes an image. A system control unit for controlling the entire forming apparatus is connected to enable power supply to the system control unit, and at least a power supply line connected to the system control unit among the power supply blocks is provided with a power supply line. Switch means for turning on and off is provided, and further, switch means control means is provided that consumes less power than the system control section and is capable of on / off control of the switch means. By the switch means control means, the system control section is provided with the switch means control means. A power saving mode for turning off the power supply line of the connected power supply block, and a power supply block connected to the system control unit. Possess a normal operation mode to turn on the power supply lines of the click, further comprising a network connection means for connecting to the network, and network invalidation means for setting an enable or disable of the function of the network connection means, the network When the validity setting of the function of the network connection means is made by the validity / invalidity setting means, the switch means control means prohibits the off control to the switch means, and the function of the network connection means by the network validity / invalidity setting means And an on / off prohibition / permission determination means for permitting the switch means control means to turn off the switch means when the invalid setting is made .

  According to a second aspect of the present invention, there is provided an image forming apparatus according to the first aspect, further comprising a switch means driving circuit for driving the switch means in response to an on / off command instructed by the switch means control means.

  According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein the power supply block connected to the system controller is included in a main power supply for performing image formation. The switch means is provided in a power supply line of a main power supply, and an auxiliary power supply capable of always supplying power is connected to the switch means control means.

  According to a fourth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to third aspects, wherein the system control unit can control power supply to other power supply blocks. .

  According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the fourth aspect, wherein the system control unit has a mode in which power supply to other power supply blocks is controlled to be turned off or supplied power amount is reduced. Features.

  According to a sixth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to fifth aspects, further comprising normal operation return means for returning from the power saving mode to the normal operation mode.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the normal operation return means is a power start command means accessible by a user or a clock means having an alarm function. It is characterized by being configured.

  According to an eighth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to seventh aspects, further comprising: a power saving mode shift means for shifting from the normal operation mode to the power saving mode.

  According to a ninth aspect of the invention, there is provided the image forming apparatus according to any one of the first to eighth aspects, wherein the power saving mode transition means is constituted by a power saving command means accessible by a user or a clock means having an alarm function. It is characterized by being.

According to a tenth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to ninth aspects, wherein the switch means control section generates a switch means control signal in response to a power saving mode transition command. And a switch means control signal delay section for delaying the switch means control signal, and the switch means control signal delay section switches to the power saving mode when returning from the power saving mode to the normal operation mode. When the time interval from the transition to the command to return to the normal operation mode is a predetermined time or less, the switch means control signal for shifting to the normal operation mode by the return command is delayed by a predetermined time, and the time interval When the time exceeds the predetermined time, the switch means control signal is not delayed.

According to an eleventh aspect of the present invention, there is provided an image forming apparatus according to the tenth aspect, further comprising a monostable multivibrator that triggers at an OFF edge of a switch control signal for shifting to a power saving mode. The switch control signal level change is masked for a predetermined time.

According to a twelfth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to eleventh aspects, wherein the switch means control circuit is constituted by a logic circuit that does not use a CPU.

According to the present invention, in the normal operation mode, power is supplied from the power supply block to the system control unit that controls the entire image forming apparatus through the power supply line, and the entire image forming apparatus is controlled by the system control unit. Formation is possible. In addition, it is desirable that the system control unit can shift to the power saving mode (low power mode) by controlling the power of another power supply block.
On the other hand, in the power saving mode, at least the switch means in the power supply block connected to the system control unit is controlled by the switch means control means, and the power supply line of the power supply block is turned off. As a result, power consumption is further reduced as compared to the case where the system control unit is always energized. In a state where the system control unit is not energized, it is desirable that other power supply blocks controlled by the system control unit also stop energizing the power supply block.

The transition to the power saving mode can be performed based on a command from the power saving mode transition means. Examples of the power saving mode transition means include a power saving command (such as a power saving button) accessible by the user and a clock means having an alarm function. Can be illustrated. As the clock means, one operating by using electric power supplied to a built-in power supply or switch means control means can be used. The clock means can issue a command to the power saving mode after the image forming apparatus has stopped for a predetermined time. The switch means control means issues an on / off command based on the transition command, and drives the switch means on and off by, for example, a switch means drive circuit.
In addition, as a switch means, it can comprise by the relay provided, for example in the electric power supply line. The relay is turned off by a control signal issued by an off command, for example.

  The power supply block connected to the system control unit may be included in a main power supply for performing image formation. The main power supply is normally AC input. By providing the switch means in the power supply line of the main power supply, the power saving effect can be enhanced by cutting off the power supply to most of the components in the power saving mode. Further, it is desirable that an auxiliary power supply independent of the main power source is connected to the switch means control means so that power can be supplied to the switch means control means at all times by the auxiliary power supply. The switch means control means is preferably composed of a logic circuit that does not use a CPU. Thereby, the power consumption in the switch means control means can be further reduced.

The return from the power saving mode to the normal operation mode can be performed by a command from the normal operation return means. Examples of the normal operation return means include power activation command means (sub power button etc.) accessible by the user, clock means having an alarm function, and the like. As the clock means, it is possible to use one that operates by using power supplied to a built-in power source or switch means control means. In the clock means, for example, a reservation time can be determined and a command to the normal operation mode can be issued when the reservation time is reached.
The switch means control means that has received the return command issues a command to turn on the switch means. The command may generate a control signal for turning on or stop sending a control signal for turning off.

Note that in an image forming apparatus having a network function, a system control unit needs to be operating for network monitoring. Therefore, in the present invention, the validity / invalidity of the network connection means connected to the network can be set by the network validity / invalidity setting means, and when the network function is valid, the off control to the switch means is prohibited and the network enabling monitoring, when functions of the network connection means is disabled you shall allow off control to the switch means. The above prohibition and permission can be determined by on / off prohibition / permission determination means.

  The network valid / invalid setting means can be performed by, for example, a software setting switch controlled by the system control unit, and can be configured by being included in the system control unit. The setting switch can be performed by, for example, a dip switch. Further, the network valid / invalid setting means can be configured to be set by a switch that can be operated by being displayed on the touch panel, and may be provided as an operation button on an operation panel or the like. Based on the setting result by the network valid / invalid setting means, the switch means control means is controlled by the on / off prohibition / permission determination means. The on / off prohibition / permission determination means can be constituted by, for example, a CPU included in the system control unit and a program for operating the CPU, and issues a control command to the switch means control means based on the determination. The command can be output as a power control signal for the switch means control means, for example.

  In addition, when the mode is switched between the power saving mode and the normal operation mode, if the mode is changed to the normal operation mode in a short time after entering the power saving mode, the operation of the switch means can be performed in a short time. However, there is a problem that the start-up failure of the power source and the contact life of the switch means are reduced. A method of avoiding unstable voltage by delaying an output-side switch with respect to an input-side switch when turning on / off with a power supply has been proposed (Patent Document 2). Is turned on and off in a short time, it is difficult to prevent a failure in starting the power source and a decrease in the contact life of the switch means in the above configuration.

  For this, the switch means control section is provided with a switch means control signal generation section for generating a switch means control signal in response to a power saving mode transition command, and a switch means control signal delay section so that the power saving mode is changed to the normal operation mode. When returning, when the time from the transition to the power saving mode to the normal operation mode return command is a predetermined time or less, the delay unit delays the switch means control signal by a predetermined time, and the time interval exceeds the predetermined time. There may be no delay. As a result, it is possible to prevent a failure in starting the power source and a decrease in the contact life of the switch means during the mode transition in a short time.

  The configuration of the delay unit is not limited to a specific one. For example, in the case where a switch control signal is generated to control the switch means to be off, the monostable multivibrator is triggered at the OFF edge of the control signal. Further, a signal delayed by a predetermined time can be obtained by masking the level change of the switch control signal for a predetermined time.

That is, according to the image forming apparatus of the present invention, a plurality of power supply blocks for controlling or driving each component of the image forming apparatus are provided, and one of the power supply blocks is a system control unit for controlling the entire image forming apparatus. Is connected to enable power supply to the system control unit, and among the power supply blocks, at least a power supply block connected to the system control unit is provided with switch means for turning on and off the power supply line, and There is provided switch means control means that consumes less power than the system control section and is capable of on / off control of the switch means, and the power supply line of the power supply block connected to the system control section by the switch means control means And turn on the power supply line of the power block connected to the system controller Since having a normal operation mode that can be the power consumption of the system controller to zero in the power saving mode, the operating state according to a more low power consumption switching means controlling means.
Further, the network connection means for connecting to the network, the network validity / invalidity setting means for setting the validity / invalidity of the function of the network connection means, and the validity setting of the function of the network connection means are made by the network validity / invalidity setting means. When the switch means control means prohibits off control to the switch means, and the network setting means disables the function of the network valid / invalid connection means, the switch by the switch means control means On / off prohibition / permission determination means for permitting off control to the means, and when it is necessary to monitor communication from the outside through a network such as a LAN or a telephone line, the system control is operated to Enables monitoring of communication and the network If the communication is not necessary, turn off the power supply to the system controller, it is possible to achieve power saving in accordance with the operational state of the image forming apparatus. In communication via the network, data can be exchanged with other image forming apparatuses, terminal devices, and servers via a LAN, etc., and with other facsimile functions via a telephone line. Data can be exchanged.

  The power supply block connected to the system control unit is included in the main power supply for image formation, and the switch means is provided in the power supply line of the main power supply. If an auxiliary power supply capable of supplying power is connected, the power consumption can be reduced to the power consumption in the switch means control means in the power saving mode, and further power saving can be achieved.

  In addition, the system control unit is capable of controlling power supply to other power supply blocks, and has a low power mode for performing off control of power supply to other power supply blocks or reduction control of the amount of power supply. Thus, power saving in multiple stages is possible, and power consumption control according to the operating state of the apparatus becomes possible.

  The switch means control section is provided with a switch means control signal generating section for generating a switch means control signal in response to a power saving mode transition command, and a switch means control signal delay section. When returning from the normal operation mode to the normal operation mode, when the time interval from the transition to the power saving mode to the command to return to the normal operation mode is equal to or less than a predetermined time, the switch means control to shift to the power saving mode by the return command If the signal is delayed for a predetermined time and the switch means control signal is not delayed when the time interval exceeds the predetermined time, the transition from the power saving mode to the normal operation mode is made in a short time. In addition, the control signal can be delayed to prevent a failure in starting the power supply and a decrease in the contact life of the switch means.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a conceptual diagram illustrating a cross-sectional configuration example of a digital copying machine 10 that is one of image forming apparatuses.
An original reading unit 11 is provided in the upper part of the apparatus main body A. The apparatus main body A includes an overall control unit 15, paper feed cassettes 14A and 14B, an image writing unit 60, an image forming unit 70, and the like. The document reading unit 11 has an automatic document feeder (hereinafter referred to as ADF) 40, and automatically feeds a desired document 20 by the ADF 40 or places a document on a platen glass 51 described later. Read the original image.
The ADF 40 includes a document placing portion 41, a roller 42 a, a roller 42 b, a roller 43, a transport roller 44, and a paper discharge tray 46. These rollers 42a, 42b, 43 and the conveying roller 44 are driven by a DC motor (not shown). That is, when the automatic paper feeding mode is selected, the original 20 fed out from the original placing portion 41 is conveyed by the downstream roller 43 so as to rotate in a U-shape, and the image is read on the plantain 52 described later. . Thereafter, the document 20 is transported by the transport roller 44 and discharged to the discharge tray 46.

On the other hand, on the upper side in the main unit A, the first platen glass 51, the second platen glass 52, the light sources 53a, 53b, the mirrors 54a, 54b, 55a, 55b, 56a, 56b, the imaging optical unit 57, A CCD imaging device 58 and an optical drive unit (not shown) are provided. In the platen mode, a document (not shown) placed on the platen glass 51 is read. At this time, the optical drive unit scans the light source 53a and the mirror 54a by driving a DC motor (not shown). Irradiation light emitted from the light source 53a to the original is reflected as reading light. The reading light is imaged by the imaging optical unit 57 through the mirrors 54 a to 56 a and taken into the CCD imaging device 58.
On the other hand, in the automatic paper feeding mode, a document moving on the platen glass 52 is read. The irradiation light applied to the document from the light source 53b is reflected as reading light, imaged by the imaging optical unit 57 through the mirrors 54b to 56b, and taken into the CCD imaging device 58.

  The CCD image pickup device 58 constitutes a reduction type image sensor. An image processing means 12 is connected to the output stage of the CCD image pickup device 58, and an analog original reading signal is digitized by an A / D substrate (not shown), and digital original image data after image processing is output to the image forming means 70. Is done. In order to form an image on a predetermined sheet (recording medium) P, the image forming unit 70 includes a photosensitive drum 71, a charging unit 72, a developing unit 73, a transfer unit 74, a separating unit 75, a cleaning unit 76, and a transport mechanism. 77 and fixing means 78. The photosensitive drum 71, the developing unit 73, and the transport mechanism 77 are driven by a DC motor such as a drum motor, a developing motor, and a paper feeding motor (not shown). In addition, a drive unit such as the roller is provided with a clutch (not shown) between a power transmission mechanism that transmits power from a DC motor as necessary, and a driven roller, if necessary, An actuator using a solenoid or the like performs a separation / contact operation with the drive roller.

  A charging unit 72 is disposed above the photosensitive drum 71, and the photosensitive drum 71 is uniformly charged in advance based on a predetermined charging potential. For example, an image writing unit 60 is provided at an upper right side of the photosensitive drum 71. In the writing unit 60, the laser light is controlled by controlling the LD substrate, and the exposure potential based on the image data output from the image processing unit 12 is set. Based on this, the photosensitive drum 71 is exposed, and an electrostatic latent image is formed on the photosensitive drum 71. At this time, the laser beam is scanned on the photosensitive drum 71 by a polygon mirror driven by a polygon mirror motor.

A developing unit 73 containing toner and developer is disposed on the right side of the photosensitive drum 71 in the figure, and the electrostatic latent image exposed by the image writing unit 60 is developed by the toner supplied from the developing unit 73. . A registration roller 62 is provided below the developing unit 73. The paper P stored in the paper feed cassettes 14A and 14B located below the image forming means 70 is fed by unillustrated feed rollers and paper feed rollers provided in the paper feed cassettes 14A and 14B, respectively. Then, it is conveyed under the photosensitive drum 71 through the conveying roller 61, the registration roller 62, and the like. These feed roller, paper feed roller, transport roller 61, registration roller 62 and the like are also driven by a DC motor (not shown).
Note that when it is necessary to supply a large amount of sheets, a large-volume sheet feeding device (LCT) (not shown) can be attached to the image forming apparatus. The large-volume sheet feeding device is also provided with a conveying motor and a roller.

  A transfer unit 74 is disposed below the photosensitive drum 71, and a toner image formed on the photosensitive drum 71 through charging, exposure, and development is transferred to a sheet P whose conveyance timing is controlled by a registration roller 62. Is done. A separation unit 75 is provided adjacent to the transfer unit 74, and the paper P onto which the toner image has been transferred is separated from the photosensitive drum 71.

  A transport mechanism 77 is provided on the downstream side of the separation unit 75, and a fixing unit 78 is provided at the end thereof. In the fixing unit 78, the toner image transferred to the paper P is thermally fixed. The paper P after the fixing process is nipped by a paper discharge roller 95 driven by a paper discharge motor and discharged to a paper discharge tray or the like outside the apparatus. The paper P on which image formation has been completed by the above-described processing is not limited to the paper discharge tray, and the finisher unit (FNS) 90 may perform stapling processing, binding processing, and the like. The finisher unit 90 also includes a DC motor (not shown) for post-processing, and a different DC motor may be prepared depending on the content of the processing.

A cleaning unit 76 is provided between the conveyance mechanism unit 77 and the above-described charging unit 72 so as to face the photoconductive drum 71, and the toner remaining on the photoconductive drum 71 is cleaned. Thereafter, the process proceeds to the next copy cycle.
Further, a fan 96 driven by a motor for cooling and ventilating the inside of the apparatus main body is disposed at an appropriate position of the image forming apparatus.

The digital copying machine 10 has an AC input unit 1. The AC input unit 1 includes a main power source 2 that supplies power to each unit such as a motor of the image forming apparatus, and an auxiliary power source 3. Are connected to the main power source 2 and a system control unit 220 that includes a CPU and controls the entire image forming apparatus. The auxiliary power supply 3 is connected to a switch means control means 300 for controlling switch means described later. The switch means control means 300 is composed of a logic circuit that does not include a CPU.
Below, the electric power supply system containing the said structure is demonstrated.

A main power source 2 and an auxiliary power source 3 are connected to the AC input unit 1 via a main power source switch 1a, and a relay 110 is provided as a switch means in the power supply line 100 to the main power source 2. Yes. The relay 110 operates to open the contact by exciting the coil 111 and to close the contact by demagnetization. A switch means driving circuit 120 is connected to the relay 110, and the switch means control means 300 is connected to the switch means driving circuit 120.
A fixing heater energization control unit 240 is connected to the power supply line 100 so that AC power can be supplied. A fixing unit 78 is connected to the fixing heater energization control unit 240.

An AC-DC converter 200 is connected to the power supply line 100 on the downstream power supply side of the relay 110, and DC power rectified and smoothed by the AC-DC converter 200 can be supplied. On the secondary side of the AC-DC converter 200, a control power supply 1 generation block 210, a control power supply 2 generation block 211, a power power supply 1 generation block 212, and a power power supply 2 generation block 213 are connected in parallel as power supply blocks. Yes.
The above-described system control unit 220 is connected to the control power source 1 generation block 210, and outputs of 5V1 and 12V2 are given from the control power source 1 generation block 210 to the system control unit 220. Connected to the system control unit 220 are a display unit 430, a network connection unit 500 for connecting to a LAN or FAX line, and a load group 510 such as an A / D board and an LD board as control targets.

  The control power supply 2 generation block 211 is connected to an engine drive unit 230 for performing I / O control and driving of each component, and outputs of 5V2 and 12V2 are output from the control power supply 2 generation block 211 to the engine drive unit 230. Is given to. A load group 520 such as ADF, scanner, FNS, and LCT is connected as a control target of the engine drive unit 230. Further, a load group 530 such as a fan, a clutch, and a solenoid, and a load group 540 such as a polygon mirror motor are connected as control targets of the engine drive unit 230. The engine driving unit 230 is connected to the system control unit 220 by UART, and can be controlled by the system control unit 220.

  A load group 530 such as a fan, a clutch, and a solenoid, and a load group 540 such as a polygon mirror motor are connected to the power power source 1 generation block 212, and an output of 24V1 is given from the power power source 1 generation block 212.

  A load group 550 such as a drum motor, a development motor, a paper feed motor, a paper discharge motor, and a high voltage power supply is connected to the power power supply 2 generation block 213 via an interlock switch 551, and the output of 24V2 is generated as a power power supply 2 Given from block 213. The output of the output is interrupted by an interlock switch 551 that operates, for example, by opening and closing the cover of the image forming apparatus.

The system control unit 220 includes a CPU 221, a power supply control unit 223, a software setting switch 225, and an RTC unit 224. The CPU 221 operates by a predetermined program to control each unit of the image forming apparatus.
A power control unit 223 is connected to the CPU 221, and a power control signal is generated by the power control unit 223 according to a command from the CPU 221. The power supply control signal 1 is output to the switch means control means 300 described later, the power supply control signal 2 is output to the control power supply 2 generation block 211, and the power supply control signal 3 is output to the power power supply 1 generation block 212. The control signal 4 is output to the power power supply 2 generation block 213, and power control of each unit is performed according to the operating state of the image forming apparatus.

The CPU 221 that can receive the elapsed time from the RTC unit 224 when the stop state of the image forming apparatus has passed a predetermined time issues a command to the power supply control unit 223 and the power supply control signals 2, 3, 4. Thus, the power output of the control power supply 2 generation block 211, the power power supply generation block 212, and the power power supply 2 generation block 213 can be shifted to a power saving state in which the power output is turned off or low. As a result, the power consumption can be reduced as compared with the state where the entire image forming apparatus is operating.
The power supply control unit 223 outputs a fixing heater control signal to the fixing heater energization control unit 240, and the fixing heater energization control unit 240 outputs a fixing temperature sensor signal to the power supply control unit 223. In the power saving mode, the display of the display unit 430 can be stopped, or the fixing heater energization control unit 240 can be controlled to set the heating temperature of the fixing unit low. This can be a low power mode.

  In the state of the power saving mode or the low power mode, the CPU 221 monitors each unit sensor, the operation unit, and the network connection unit 500 of the image forming apparatus, and performs an operation to be shifted to the operation state and communication through the network connection unit 500. When done, the entire image forming apparatus can be returned from the power saving state to the operating state. In that case, according to the command to the power supply control unit 223, the power output of the control power supply 2 generation block 211, the power power supply generation block 212, and the power power supply 2 generation block 213 is turned on by each power supply control signal 2, 3, 4 Further, when the display unit 430 is turned off, display is possible, and when the temperature of the fixing unit 78 is lowered, the fixing heater energization control unit 240 is controlled by a fixing heater control signal to control the temperature of the fixing unit 78. Is raised to a predetermined temperature.

  Next, in the software setting switch 225 included in the system control unit 220, setting for enabling / disabling the function of the network connection unit 500 can be performed by operating a dip switch or the like. When the setting of the software setting switch 225 is a setting for enabling the network function, the CPU 221 receives the setting result and generates the relay control signal by the power control signal 1 sent from the system control unit 220 to the switch means control means 310. A command for stopping the operation of the unit 310 is issued. On the other hand, when the setting of the software setting switch 225 is a setting for disabling the network function, the CPU 221 operates the relay control signal generation unit 310 according to the power control signal 1 sent from the system control unit 220 to the switch unit control unit 310. And issues a command that enables generation of the relay control signal. Therefore, the CPU 221 and a program for operating the CPU 221 function as an on / off prohibition / permission determination means of the present invention.

  Further, the RTC unit 224 included in the system control unit 220 has an alarm function and also functions as a weekly timer unit. The RTC unit 224 normally holds a built-in power supply, and can continue to operate even when no power is supplied to the image forming apparatus, and can hold time information. The RTC unit 224 can issue an alarm with the passage of the time or the time by setting the alarm time or the elapsed time for the alarm in advance. The alarm is sent to the relay control signal generation unit 310 and can function as a normal operation return unit and a power saving mode transition unit, which will be described later.

  The switch unit control unit 300 includes a relay control signal generation unit 310 that generates a relay control signal as a switch unit control signal, and a delay circuit 320 as a switch unit control signal delay unit. 3 is used to supply 5V0. The relay control signal generator 310 is connected to a sub power switch 410, a power saving button 420, and a power saving LED 430 provided on the operation panel 400. The sub power switch 410 and the power saving button 420 are also connected to the system control unit 220.

  The sub power switch 410 is accessible by the user and functions as a power activation command means (normal operation return means) for returning to the normal operation mode when the image forming apparatus is in the power saving mode or in the power saving state. To do. When the sub power switch 410 is off, the state can be recognized by the relay control signal generation unit 310 and the system control unit 220, and the power saving mode or the normal operation mode prior to the transition to the power saving mode is maintained. On the other hand, when the sub power switch 410 is turned on or an alarm is issued from the RTC unit 224 as a normal operation return command, the state can be recognized by the relay control signal generation unit 310 and the system control unit 220. When the image forming apparatus is in the normal operation mode, the subsequent operation is not performed regardless of whether the sub power switch 410 is on or the alarm. On the other hand, when the image forming apparatus is in the power saving mode, the relay control signal generation unit 310 receives the above operation as a return command and performs an operation for turning on the relay 110. In this embodiment, the relay control signal as an OFF command is set to a low level, the relay 110 is demagnetized, and the contact is turned on. Then, energization to the AC-DC converter 200 is started, power is supplied to each power supply block, and the system control unit 220 also operates. As a result, an image can be formed.

  Next, the power saving button 420 is accessible by the user, and when the image forming apparatus is in a normal operation mode (including a low power mode) or in a power saving state, a power saving command means for shifting to the power saving mode. It functions as (means more than power saving mode). When the power saving button 420 is off, the state can be recognized by the relay control signal generation unit 310 and the system control unit 220, and the normal operation mode or the power saving mode before the transition to the normal operation mode is maintained. On the other hand, when the power saving button 420 is turned on or the alarm is issued as a power saving mode transition command, the state can be recognized by the relay control signal generation unit 310 and the system control unit 220. When the image forming apparatus is already in the power saving mode, the subsequent operation is not performed regardless of whether the power saving switch 420 is on. On the other hand, when the image forming apparatus is in the normal operation mode, the relay control signal generation unit 310 receives the operation or alarm as a power saving mode transition command and performs an operation for turning off the relay 110. In this embodiment, a relay control signal as an off command is set to a high level, a relay control signal is sent to the relay drive circuit 111, the relay 110 is excited, and the contact is turned off. Then, energization to the AC-DC converter 200 is stopped, power supply to each power supply block is turned off, and the system control unit 220 also stops operation. As a result, the image forming apparatus is in a state where the switch unit control unit 300 is energized only through the auxiliary power source 3. As the power saving mode is shifted, the relay control signal generation unit 310 supplies power to the power saving LED 421 to notify the user that it is in a power saving state. Thus, by using the power saving mode display means such as the power saving LED 421, the user can immediately recognize that the image forming apparatus is in the power saving state.

Next, an operation procedure including power supply control in the image forming apparatus will be described based on the flowchart of FIG.
First, the image forming apparatus is operated by turning on the main power switch 1a and the sub power switch 410 (step s0). Then, the system control unit 220 performs system initialization and warms up (step s1). Next, a copy operation is performed according to a user instruction or the like (step s2). When copying is completed (step s3), the standby state is entered (step s4). In this state, pressing of the power saving button is monitored by an interruption (step I0). When the specified time elapses from the standby state, the mode shifts to the low power mode (step s6). The specified time for shifting to the low power mode is determined in advance and is stored and managed in an appropriate storage medium such as a flash memory. The CPU 221 receives the output from the RTC unit 224 and counts the passage of the specified time. In the low power mode, control for reducing a predetermined power is performed (for example, temperature reduction of the fixing unit, power reduction in each power supply block, display off in the display unit, etc.). Even in the low power mode, pressing of the power saving button is monitored by interrupt processing (step I0). Similarly, the release of the low power mode is monitored (step L0). To cancel the low power mode, as described above, the operation of various operation units by the user, document setting, communication through the network connection means, and the like are executed as commands. When the CPU 221 determines that there is an operation for canceling the low power mode or the like, the CPU returns to the normal operation from the low power mode (step L1), and proceeds to the above-described step S1.

  In the low power mode, the power saving time and the lapse of the specified time are monitored (step s7), and the mode is shifted to the power saving mode when the time and time that satisfy the conditions are satisfied (step s8). Also, in the power saving button depressing monitoring described above, when the depressing of the power saving button is detected (step I1), the mode is similarly shifted to the power saving mode (step s8). After the transition to the power saving mode, it is determined whether or not the network connection function is enabled by the software setting switch 225 (step s9). Here, when the network connection function is not valid and is set to invalid, an off command is issued by the power control signal 1, and the relay 110 is turned off by the switch means control means 300 (step s10). As a result, energization to the system control unit and the like other than the switch unit control unit 300 is stopped, and the power saving mode 2 with the lowest power consumption is achieved (step s11). Thereafter, it is determined whether or not the sub power switch 410 is depressed or a preset time (weekly timer) has arrived (step s12). If any of these is determined to be positive, the switch means control means 300 Control to turn on the relay 110 is performed. As a result, the power supply to each power supply block including the system control unit 220 is resumed, the power supply control signals 1 to 4 are also turned on (step s13), and the normal operation mode is restored (step s30).

  On the other hand, if the network function is set to be effective in step s9, the control by the system control unit 220 is prohibited, the power control signals 2, 3, and 4 are turned off, and the system control unit 220 is energized. Continue (step s20). Thereby, it will be in the state of the power saving mode 1 which reduced electric power consumption to some extent (step s21). Thereafter, it is determined whether or not there is a depressing of the sub power switch 410, a return request through the network, or the arrival of a preset time (weekly timer) (step s22), and if any of these is determined to be positive Then, the system control unit 220 turns on the power control signals 2, 3, and 4 (step s23), and returns to the normal operation mode (step s30).

In this embodiment, when the relay control signal is generated and applied to the relay, it is output to the drive circuit through the delay circuit. The delay operation will be described below together with details of the configuration of the delay circuit 320 and the drive circuit 111.
The relay control signal generated and output by the relay control signal generation unit 310 is a signal whose OFF signal becomes Hi, and is added to the base of the pnp transistor 321 constituting the inverting unit on the input side of the delay circuit 320. ing. A reference potential is applied to the emitter of the transistor 321, and a resistor 322 is connected between the emitter and the base. In the inverting unit, the relay control signal input to the base is inverted between the base and collector, and an inverted signal in which the off signal is Lo and the on signal is Hi is obtained on the collector side of the transistor 321. The inverted signal is input to the / A terminal of the IC 1 constituting the monostable multivibrator 324, and the inverted signal is also input to the base side E point of the npn transistor 329 through the resistor 323.

In the monostable multivibrator 324, the Lo signal is generated by the off-edge of the signal input to the terminal / A, and the output becomes Hi after the time determined by Tw. Therefore, the change of the input signal is masked within the time Tw. Tw is the capacitance of the capacitor 325 (C1) connected between the Cx terminal and the Rx / Cx terminal of the monostable multivibrator 324, and the resistor 326 connected to the Rx / Cx terminal with a reference potential applied to one end. It is determined by the resistance value of (R1). A diode 327 connected in parallel with the resistor 326 is for protecting the monostable multivibrator 324.
Tw is determined by R1 · C1, and for example, when R1: 10 kΩ and C1: 100 μF, Tw = 10 kΩ × 100 μF = 1.0 seconds. Therefore, arbitrary Tw can be obtained by changing the values of R1 and C1.

  The signal masked as described above is output from the terminal / Q, and is input to the base E point of the transistor 329 together with the inverted signal via the diode D1 whose flow direction is directed to the terminal / Q. At the point E, an AND circuit is configured by the diode 328, and only when the signal applied to the point E is Hi, it becomes a Hi signal, and when either is Lo, it becomes a Lo signal and becomes the base of the transistor 329. Is input. In the transistor 329, a resistor 330 is connected between the base and the emitter, and the emitter is grounded. In addition, a potential is applied to the collector via the resistor 122 of the relay drive circuit 120. With this structure, an inverted signal is output to the collector side of the transistor 329 by a signal applied to the base of the transistor 329. The signal is applied to the base of the transistor 121 of the relay drive circuit 120, and the amplified emitter signal is further applied to the base of the transistor 123 for relay drive. The collector of the transistor 123 is connected to the coil 111 of the relay 120 and is further supplied with a potential. A diode 124 connected in parallel with the relay 111 is for preventing a backflow.

The relay control signal delay processing with the above configuration will be further described with reference to FIGS.
The relay control signal that sets the OFF signal to Hi is inverted and then input to the monostable multivibrator 324. The inverted signal becomes a Lo signal having a length of 1.0 second by the monostable multivibrator 324 and merges with the inverted signal. Here, when the relay control signal input to the delay circuit is 1.0 second or less (FIG. 5), the inverted signal is also a Lo signal having a length of 1.0 second or less. By the AND circuit, the Lo signal is 1.0 seconds long. The relay control signal output from the delay circuit 310 is output as a signal delayed to a length of 1.0 second. As a result, the relay is prevented from being turned off and on for a short period of time not longer than a predetermined time (here, 1.0 second).

On the other hand, when the relay control signal input to the delay circuit is a Hi signal having a length exceeding 1.0 seconds (FIG. 6), the inverted signal also becomes a Lo signal exceeding 1.0 seconds, and has a length of 1.0 seconds. As a result, the delay circuit 310 finally outputs a control signal having the same length as the relay control signal input to the delay circuit 310. That is, when the relay control signal has a length exceeding the predetermined time, it is output to the relay drive circuit without delay.
As described above, the delay process is performed only in the case of short-time off-on, and in other cases, the control is quickly performed. In short-time off-on, delay processing effectively prevents power supply start-up failure and contact life reduction of the switch means.

1 is a diagram illustrating a cross-sectional configuration of a copying machine according to an embodiment of the present invention. Similarly, it is a block diagram of a configuration including a power supply system. Similarly, a flowchart showing a processing procedure including mode transition is shown. Similarly, it is a figure which shows a delay circuit and a drive circuit. Similarly, it is a figure which shows the signal processing when the delay process of a relay control signal is required in a delay circuit. It is a figure which shows the signal processing in case the delay processing of a relay control signal is similarly made unnecessary in a delay circuit.

Explanation of symbols

1 AC Input Unit 2 Main Power Supply 3 Auxiliary Power Supply 10 Copier 100 Power Supply Line 110 Relay 120 Relay Drive Circuit 210 Control Power Supply 1 Generation Block 211 Control Power Supply 2 Generation Block 212 Power Power Supply 1 Generation Block 213 Power Power Supply 2 Generation Block 220 System Control Unit 221 CPU
223 Power control unit 224 RTC unit 225 Software setting switch 300 Switch unit control unit 310 Relay control signal generation unit 320 Delay circuit 410 Sub power switch 420 Power saving button 500 Network connection unit

Claims (12)

There are a plurality of power supply blocks for controlling or driving each component of the image forming apparatus, and one of the power supply blocks is connected to a system control unit for controlling the entire image forming apparatus to supply power to the system control unit. The power supply block connected to the system control unit is provided with switch means for turning on and off the power supply line, and further consumes less power than the system control unit. There is provided switch means control means capable of on / off control of the switch means, and the switch means control means turns off a power supply line of a power supply block connected to the system control section, and the system control. the power supply line of the connected power supply block in part have a normal operation mode to turn on, further, Ne Network connection means for connecting to a network, network validity / invalidity setting means for setting validity / invalidity of the function of the network connection means, and validity setting of the function of the network connection means by the network validity / invalidity setting means When the switch means control means prohibits off control to the switch means, and the network valid / invalid setting means disables the function of the network connection means to the switch means by the switch means control means. An image forming apparatus comprising: an on / off prohibition / permission determination unit that permits the off control of the image forming apparatus. 2. The image forming apparatus according to claim 1, further comprising a switch means driving circuit for driving the switch means in response to an on / off command instructed by the switch means control means. A power supply block connected to the system control unit is included in a main power supply for performing image formation. The switch means is provided in a power supply line of the main power supply, and the switch means control means The image forming apparatus according to claim 1, wherein an auxiliary power supply capable of constantly supplying power is connected. The image forming apparatus according to claim 1, wherein the system control unit is capable of controlling power supply of another power supply block. The image forming apparatus according to claim 4, further comprising a mode in which the system control unit performs power supply off control or power supply reduction control to another power supply block. The image forming apparatus according to claim 1, further comprising a normal operation return unit that returns the power saving mode to the normal operation mode. The image forming apparatus according to claim 1, wherein the normal operation return unit includes a power activation command unit accessible by a user or a clock unit having an alarm function. The image forming apparatus according to claim 1, further comprising: a power saving mode shift unit configured to shift from the normal operation mode to the power saving mode. The image forming apparatus according to claim 1, wherein the power saving mode transition unit includes a power saving command unit accessible by a user or a clock unit having an alarm function. The switch means control section includes a switch means control signal generation section that generates a switch means control signal in response to a power saving mode transition command, and a switch means control signal delay section that delays the switch means control signal. When returning from the power saving mode to the normal operation mode, the control signal delay unit performs the return when the time interval from the transition to the power saving mode to the command to return to the normal operation mode is equal to or less than a predetermined time. The switch means control signal for shifting to the normal operation mode by a command is delayed for a predetermined time, and when the time interval exceeds the predetermined time, the switch means control signal is not delayed. The image forming apparatus according to any one of 1 to 9 . A monostable multivibrator that triggers at an OFF edge of a switch control signal for shifting to a power saving mode, wherein the monostable multivibrator masks a level change of the switch control signal for a predetermined time. The image forming apparatus according to claim 10 . The image forming apparatus according to any one of claims 1 to 11, characterized in that said switching means controlling means is constituted by a logic circuit without using the CPU.

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