JP2009278836A - Switching power circuit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching power circuit capable of reducing power loss in a high load while suppressing an increase in power loss in a low load, and an image forming apparatus including the switching power circuit. <P>SOLUTION: The switching power circuit has current switching FETs Q1, Q2 and Q3 mutually connected in parallel and a connecting terminal 202 acquiring power information related to electric energy required by a load circuit. The switching power circuit further has a switching control section 205 controlling the switching operations of the FETs Q1, Q2 and Q3 so that the number of switching elements for switching in the FETs Q1, Q2 and Q3 increases with the increase of the electric energy indicated by the power information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a switching power supply circuit and an image forming apparatus including the same.

  FIG. 5 is a circuit diagram showing a switching power supply circuit 100 according to the background art. The switching power supply circuit 100 shown in FIG. 5 generates a DC voltage by rectifying the AC voltage supplied from the commercial AC power supply AC by the diode bridge 101 and smoothing it by the capacitor 102. The DC voltage is switched at high frequency by FETs (Field Effect Transistors) 104 and 105 connected in parallel, so that a high frequency current flows through the primary winding of the transformer 103.

  Then, a high frequency voltage is induced in the secondary winding of the transformer 103, and this is rectified by the diode 106, smoothed by the capacitor 107, and converted into a DC voltage. This DC voltage is supplied to the load 110 as the output voltage of the switching power supply circuit 100. The DC voltage is divided by a series circuit of resistors 108 and 109, and the divided voltage is fed back to the PWM control circuit 112 via the photocoupler 111.

  The PWM control circuit 112 controls the duty ratio for turning on and off the FETs 104 and 105 so that the output voltage becomes a desired voltage according to the divided voltage. The PWM control circuit 112 is connected to the gates of the FETs 104 and 105 via the resistors 113, 114, and 115. The resistors 114 and 115 are charging resistors for the gate, and the resistor 115 is a synchronous resistor. The resistor 113 is connected in parallel with a discharge diode 116 for quickly discharging the gate charge when the FETs 104 and 105 are turned off.

  The switching power supply circuit 100 reduces the power loss generated in the switching element by connecting two FETs for current switching in parallel, thereby reducing the on-resistance in the FET as compared with the case of one FET. Yes.

In addition, a technique for reducing the switching loss by shortening the turn-off time of the switching element is also known (see, for example, Patent Document 1).
JP 2004-147452 A

  By the way, as for the power loss in the switching element, when the current decreases, the switching loss becomes larger than the loss due to the on-resistance. Then, as described above, when two switching elements are connected in parallel, the switching loss is doubled. Therefore, when the load current is low and the load is low, the power loss due to the switching element is increased. was there.

  Moreover, since the technique described in Patent Document 1 can reduce the switching loss, it is possible to effectively reduce the power loss when the load current is low and the load is low. On the other hand, when the load current is large, the power loss caused by the on-resistance is larger than the switching loss. However, the technique described in Patent Document 1 cannot reduce the power loss due to the on-resistance that occurs when the switching element is in the on state. Therefore, the effect of reducing the power loss is small when the load current is high and the load is high. There was an inconvenience.

  The present invention has been made in view of such circumstances, and a switching power supply circuit capable of reducing power loss at high load while suppressing an increase in power loss at low load, and An object is to provide an image forming apparatus provided.

  A switching power supply circuit according to the present invention is a switching power supply circuit that generates a desired voltage by repeating current switching and outputs the voltage to a load circuit. The switching element, a power information acquisition unit that acquires power information related to the amount of power required by the load circuit, and the greater the amount of power indicated by the power information acquired by the power information acquisition unit, A switching control unit that controls switching operations of the plurality of switching elements so that the number of switching elements used for the switching among the elements increases.

  According to this configuration, the power information regarding the amount of power required by the load circuit is acquired by the power information acquisition unit. Then, the switching control unit switches the switching elements so that the larger the amount of power indicated by the power information, the larger the number of switching elements used for switching among the plurality of switching elements connected in parallel. Operation is controlled.

  Then, at the time of a low load where the influence of the switching loss is large, the number of switching elements used for switching is reduced and the switching loss is reduced. On the other hand, at the time of high load where the influence of the power loss due to the on-resistance of the switching element becomes large, the number of switching elements used for switching is increased, and the power loss due to the on-resistance is reduced by increasing the number of parallel switching elements. The Thereby, the power loss at the time of high load can be reduced while suppressing the increase of the power loss at the time of low load.

  Moreover, it is preferable that the load circuit has a plurality of operating states with different power consumption, and the power information acquisition unit acquires information indicating the operating state of the load circuit as the power information.

  According to this configuration, the switching control unit only needs to set the number of switching elements used for switching in accordance with the operation state, so that the setting process of the number of switching elements is simplified.

  The load circuit preferably has, as the plurality of operation states, a normal mode in which normal operation is performed and a power saving mode in which power consumption is lower than that in the normal mode.

  According to this configuration, since it is considered that the power consumption of the load circuit is greatly different between the normal mode and the power saving mode, the switching control unit is used for switching depending on whether it is the normal mode or the power saving mode. If the number of switching elements is set, power loss can be effectively reduced.

  Preferably, the plurality of switching elements are FETs, and the gates of the FETs are connected to the switching control unit via a parallel circuit of a gate charge discharging diode and a resistor, respectively.

  When a plurality of FETs are connected in parallel, the flowing currents are balanced by the FETs, which is suitable as the switching element. Moreover, since the turn-off time of the FET is shortened by the diode, the switching loss is reduced.

  An image forming apparatus according to the present invention includes the above-described switching power supply circuit, the load circuit, and an operation state transmission unit that transmits information indicating the operation state to the power information acquisition unit as the power information. The load circuit preferably includes an image forming unit that forms an image on a sheet.

  According to this configuration, information indicating the operation state of the image forming apparatus is transmitted as power information to the power information acquisition unit by the operation state transmission unit. In the switching power supply circuit of the image forming apparatus, the number of switching elements used for switching is set according to the operation state of the image forming apparatus, so that an increase in power loss at low load is suppressed in the image forming apparatus. However, power loss at high load can be reduced.

  The load circuit further includes a reading unit that reads an image from a document, and the operation state transmission unit further uses the information indicating the operation of the reading unit and the operation of the image forming unit as the power information. It is preferable to transmit to the power information acquisition unit.

  In the image forming apparatus, the operation of the reading unit, the operation of the image forming unit, and the parallel operation of the reading unit and the image forming unit are the main operation states that affect power consumption in the image forming apparatus. Is suitable as power information.

  In the information indicating the operation of each unit indicated by the power information received by the power information acquisition unit, the switching control unit increases the number of operating parts, and the number of switching elements used for the switching increases. Thus, it is preferable to control switching operations of the plurality of switching elements.

  In the information indicating the operation of each part indicated by the power information, it is considered that the power consumption increases as the number of operating parts increases, that is, as the number of operating parts in parallel increases. If the number of switching elements used for switching increases, it is easy to reduce power loss at high load while suppressing increase in power loss at low load.

  In the switching power supply circuit and the image forming apparatus having such a configuration, the switching loss is reduced by reducing the number of switching elements used for switching at a low load where the influence of the switching loss is large. On the other hand, the power loss due to the on-resistance of the switching element increases, and at the time of high load, the number of switching elements used for switching is increased, and the number of switching elements in parallel is increased, thereby reducing the power loss due to the on-resistance. Is done. Thereby, the power loss at the time of high load can be reduced while suppressing the increase of the power loss at the time of low load.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a side view schematically showing an internal configuration of a copying machine as an example of an image forming apparatus using a switching power supply circuit according to an embodiment of the present invention. FIG. 2 is a block diagram showing an example of the electrical configuration of the copying machine 1 shown in FIG. Note that the image forming apparatus is not limited to a copying machine, and may be, for example, a printer, a facsimile, or a complex machine that combines these.

  The copying machine 1 includes a main body unit 2, a post-processing unit 3 disposed on the paper carry-out side of the main body unit 2, for example, the left side, and a document reading unit 5 (reading unit) disposed on the upper part of the main body unit 2. The document feeding unit 6 disposed above the document reading unit 5, the control unit 10 disposed inside the main body unit 2, and a switching power supply circuit 200. A substantially rectangular operation panel 47 is provided at the front portion of the copying machine 1.

  The operation panel 47 includes a display unit 473 formed of an LCD (Liquid Crystal Display) or the like, and an operation key unit 476 for inputting an operation instruction from the operator. The operation key unit 476 includes a start button 471, a power saving key 472, and the like.

  The start button 471 receives an instruction to start each operation such as a copy operation and a scan operation from the operator. The power saving key 472 is a key that receives an instruction from the operator to shift the copying machine 1 to a power saving mode that consumes less power than the normal mode in which the normal operation is performed.

  The display unit 473 includes a touch panel unit that combines a touch panel and an LCD. The display unit 473 displays various operation screens, and the operator can input execution commands for various settings and functions by pressing the display screen (displayed operation keys). .

  The document reading unit 5 includes a scanner 51 including a CCD (Charge Coupled Device) 512, an exposure lamp 511, and the like, and a document table 52 and a document reading slit 53 made of a transparent member such as glass. The scanner 51 is configured to be movable by a drive unit (not shown). When reading a document placed on the document table 52, the scanner 51 is moved along the document surface at a position facing the document table 52 to scan the document image. The acquired image data is output to the control unit 10. Further, when reading a document fed by the document feeding unit 6, the document is moved to a position facing the document reading slit 53 and synchronized with the document feeding operation by the document feeding unit 6 via the document reading slit 53. The image of the original is acquired and the image data is output to the control unit 10.

  The document feeding unit 6 includes a document placement unit 601, a paper feed roller 602, a document transport unit 603, and a document discharge unit 604. The paper feed roller 602 feeds the required number of documents set on the document placement unit 601 one by one, and the document transport unit 603 sequentially transports the fed document to the reading position of the scanner 51. The scanner 51 sequentially reads images of the conveyed document, and the read document is discharged to the document discharge unit 604. The document conveyance unit 603 further includes a sheet reversing mechanism that reverses the document and reversely conveys the document to a position facing the document reading slit 53, so that images on both sides of the document can be read from the scanner 51 via the document reading slit 53. ing.

  The document feeding unit 6 is provided so as to be rotatable with respect to the main body unit 2 so that the front side thereof can move upward. By moving the front side of the document feeder 6 upward to open the upper surface of the document table 52, the user can place a read document, such as a book in a spread state, on the upper surface of the document table 52. ing.

  The main body 2 includes a manual feed tray 460, a plurality of paper feed cassettes 461, a plurality of paper feed rollers 462, an image forming unit 4, a discharge port 209, a discharge tray 48, the control unit 10, and the like. The image forming unit 4 includes a sheet conveying unit 46 including an image forming unit 40, a fixing unit 45, and various conveying rollers provided in a sheet conveying path in the image forming unit 4. The image forming unit 40 includes a transfer roller 41, an exposure device 42, a photosensitive drum 43, and a developing device 44.

  The photosensitive drum 43 is uniformly charged by a charging device (not shown) while rotating in the direction of the arrow. The exposure device 42 scans the photosensitive drum 43 with a laser beam modulated according to the image of the document read by the document reading unit 5 to form an electrostatic latent image on the drum surface. The developing device 44 supplies a black developer to the photosensitive drum 43 to form a toner image.

  On the other hand, the paper feed roller 462 pulls out the paper from the manual feed tray 460 or the paper feed cassette 461 in which the paper is stored, and feeds the paper to the transfer roller 41. The transfer roller 41 transfers the toner image on the photosensitive drum 43 to the conveyed paper, and the fixing unit 45 heats and fixes the transferred toner image on the paper. Thereafter, the sheet is carried into the post-processing section 3 from the discharge port 209 of the main body section 2. The paper is also discharged to the discharge tray 48 as necessary.

  The post-processing unit 3 includes a carry-in port 301, a paper transport unit 302, a sorting unit 303, a paper processing unit 304, a carry-out port 305, a stack tray 306, and the like. In the post-processing unit 3, paper that needs post-processing such as stapling and punching after printing is carried into the carry-in port 301 from the discharge port 209 of the main body unit 2, and is transferred from the paper carrying unit 302 to the sorting unit 303. After being sequentially conveyed and appropriately sorted (sorted) and aligned with the leading edge, processing such as stapling and punching is performed in the paper processing unit 304 and discharged from the carry-out exit 305 to the stack tray 306. The stack tray 306 is configured to be movable up and down in the direction of the arrow according to the number of sheets stacked from the carry-out port 305.

  The control unit 10 controls operation of the entire apparatus. For example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores a predetermined control program, and data temporarily. RAM (Random Access Memory) which memorize | stores and these peripheral circuits etc. are comprised. The control unit 10 functions as the image formation control unit 11, the power saving control unit 12, and the operation state transmission unit 13 by executing a control program stored in the ROM.

  The image forming control unit 11 controls the operation of each unit of the copying machine 1 such as the image forming unit 4 and the post-processing unit 3 in accordance with various settings and operation instructions received by the operation panel 47, and the manual feed tray 460. In addition, an image of a document is formed on the paper stored in the paper feed cassette 461.

  For example, when the power saving key 472 is pressed or the operation panel 47 is not operated for a preset time, the power saving control unit 12 shifts from the normal mode to the power saving mode. In the power saving mode, the power saving control unit 12 leaves other minimum circuit blocks necessary for turning off the heater of the fixing unit 45 and receiving user operation instructions such as the operation key unit 476 and the CPU. The power consumption of the copying machine 1 is reduced by shutting off the power supply to the circuit unit or shifting the CPU of the control unit 10 to an operation mode with low power consumption.

  The operation state transmission unit 13 includes information indicating whether the mode is the normal mode or the power saving mode, and a signal indicating whether each of the document reading unit 5, the image forming unit 4, and the post-processing unit 3 is operating. Is output to the connection terminal 202 (power information acquisition unit) of the switching power supply circuit 200 as a signal Spw (power information).

  FIG. 3 is a circuit diagram showing an example of the configuration of the switching power supply circuit 200 shown in FIG. A switching power supply circuit 200 shown in FIG. 3 includes connection terminals 201, 202, 203, 204, a diode bridge D1, diodes D2, D3, D4, D5, capacitors C1, C2, a transformer T1, FETs Q1, Q2, Q3 (switching elements). , Resistors R1, R2, R3, R5, R6, a photocoupler PC1, and a switching control unit 205.

  The connection terminals 203 and 204 are connection terminals connected to the commercial AC power supply AC. Then, the AC voltage received by the connection terminals 203 and 204 is rectified by the diode bridge D1, and then smoothed by the capacitor C1. The voltage across the capacitor C1 is applied to the series circuit of the primary winding of the transformer T1 and the parallel circuit of the FETs Q1, Q2, and Q3.

  The gate of the FET Q1 is connected to the switching control unit 205 via the resistor R1 and the diode D3. The gate of the FET Q2 is connected to the switching control unit 205 via the resistor R2 and the diode D4. The gate of the FET Q3 is connected to the switching control unit 205 via the resistor R3 and the diode D5. The cathode side of the diodes D3, D4, D5 is connected to the switching control unit 205.

  As a result, when the FETs Q1, Q2, and Q3 are turned on / off according to the control signal from the switching control unit 205, a high-frequency current flows through the primary winding of the transformer T1, and a high-frequency voltage is applied to the secondary winding of the transformer T2 by electromagnetic coupling. Induced. The high frequency voltage induced in the secondary winding of the transformer T2 is rectified by the diode D2, and then smoothed by the capacitor C2, thereby generating a DC voltage.

  Further, when the FETs Q1, Q2, and Q3 are turned off, the gate charges are discharged by the diodes D3, D4, and D5, and the turn-off time is shortened. As a result, the switching loss of the FETs Q1, Q2, and Q3 is reduced. .

  This DC voltage is supplied as a power supply voltage Vop to each part of the copying machine 1 via the connection terminal 201. In this case, the circuit in the copying machine 1 that receives the supply of the power supply voltage Vop from the switching power supply circuit 200 corresponds to an example of a load circuit.

  The power supply voltage Vop is divided by a series circuit of resistors R5 and R6. Then, the divided voltage is output to the switching control unit 205 via the photocoupler PC1. Thus, since the power supply voltage Vop is fed back to the switching control unit 205, the switching control unit 205 sets a duty ratio for turning on and off the FETs Q1, Q2, and Q3 so that the fed back voltage approaches a preset target value. By changing it, the power supply voltage Vop is set to a predetermined constant voltage.

  In addition, the switching control unit 205 determines the number of FETs used for DC voltage switching among the FETs Q1, Q2, and Q3 according to the signal Spw received from the operation state transmission unit 13 via the connection terminal 202.

  The connection terminals 201, 202, 203, and 204 may be any terminals that electrically connect the control unit 10 and the switching control unit 205. For example, the connection terminals 201, 202, 203, and 204 may be electrodes, connectors, terminal blocks, and the like. It may be a wiring pattern such as a pad.

  Next, the operation of the copying machine 1 configured as described above will be described. FIG. 4 is an explanatory diagram for explaining an example of the operation of the copying machine 1 shown in FIG. In FIG. 4, the horizontal axis direction indicates the passage of time. The period in which the power saving mode is set, the period in which the normal mode is set, and the document reading unit 5, the image forming unit 4, and the post-processing unit 3 operate. The period is shown with an arrow. In each period, the number of FETs used for switching is shown.

  First, the copier 1 is set to the power saving mode by the power saving control unit 12. Then, the operation state transmission unit 13 outputs a signal Spw indicating the power saving mode to the switching control unit 205 via the connection terminal 202. In the power saving mode, the power consumption of the load circuit in the copying machine 1 is the smallest, and the switching loss is dominant in the power loss in the FETs Q1, Q2, and Q3.

  Therefore, the switching control unit 205 sets the number of high-frequency switching FETs to one, for example, turns on and off only the FET Q1, and turns off the FETs Q2 and Q3. As a result, in the power saving mode in which the load circuit requires the least amount of power, the FETs Q2 and Q3 are not switched, resulting in a reduction in FET switching loss.

  Next, for example, when the user places a bundle of documents on the document placement unit 601 and presses the start button 471, the power saving control unit 12 sets the normal mode. Then, in response to a control signal from the image formation control unit 11, the document reading unit 5 starts reading the document (timing t1). Further, the operation state transmitting unit 13 outputs a signal Spw indicating that the document reading unit 5 operates to the switching control unit 205 via the connection terminal 202.

  Then, since electric power is required to operate the document reading unit 5, the switching control unit 205 sets the number of high-frequency switching FETs to two. For example, the switching control unit 205 turns on and off only the FETs Q1 and Q2, and turns off the FET Q3. In this way, when the amount of power required by the load circuit increases and the power loss due to the on-resistance in the switching element increases, the number of FETs to be switched increases.

  When the number of FETs to be switched increases, the parallel resistance of the FET decreases and the parallel resistance value of the on-resistance decreases. As a result, an increase in power loss due to an increase in power consumption of the load circuit can be reduced.

  An original image is read by the original reading unit 5, and the image data is transmitted to the image forming unit 4. Then, the image forming unit 4 starts an image forming operation on a sheet based on the image data. At this time, since a plurality of documents are placed on the document placement unit 601, the document reading unit 5 continues to read the remaining documents.

  Then, the operation state transmitting unit 13 outputs a signal Spw indicating that the document reading unit 5 and the image forming unit 4 operate to the switching control unit 205 via the connection terminal 202 (timing t2). In FIG. 4, the switching control unit 205 shows an example in which the number of FETs to be switched at high frequency is two when the document reading unit 5 and the image forming unit 4 operate simultaneously.

  Note that the power consumption of the copying machine 1 increases as the image forming unit 4 starts a new operation. Therefore, if the effect of reducing the power loss due to the on-resistance by increasing the number of FETs to be switched is greater than the increase in switching loss of the FETs, the switching control unit 205 performs high-frequency switching at timing t2. The number of FETs may be three.

  Next, when the paper on which the image is formed by the image forming unit 4 is sent to the post-processing unit 3, the post-processing unit 3 starts its operation. Then, the operation state transmitting unit 13 outputs a signal Spw indicating that the document reading unit 5, the image forming unit 4, and the post-processing unit 3 operate to the switching control unit 205 via the connection terminal 202 (timing t3). ). Then, the switching control unit 205 sets the number of high-frequency switching FETs to three. That is, the switching control unit 205 turns on and off the FETs Q1, Q2, and Q3 to perform high frequency switching.

  In this way, when the amount of power required by the load circuit increases and the power loss due to the on-resistance in the switching element increases, the number of FETs to be switched increases. When the number of FETs to be switched increases, the parallel resistance of the FET decreases and the parallel resistance value of the on-resistance decreases. As a result, an increase in power loss due to an increase in power consumption of the load circuit can be reduced.

  Next, when the document reading unit 5 finishes reading the document bundle placed on the document placing unit 601, the operation state transmitting unit 13 causes the image forming unit 4 and the post-processing unit 3 to operate. The signal Spw shown is output to the switching control unit 205 via the connection terminal 202 (timing t4). Then, since the power consumption of the load circuit is reduced and the influence of the switching loss becomes larger than the power loss caused by the on-resistance of the FET, the switching control unit 205 reduces the number of FETs to be switched at high frequency to two.

  As described above, the switching control unit 205 performs switching so that the sum of the power loss caused by the on-resistance of the FET and the switching loss becomes smaller according to the operating state of the load circuit, that is, the power consumption of the load circuit. Since the number of FETs to be used can be changed, it is possible to reduce power loss at high loads while suppressing an increase in power loss at low loads.

  Note that the signal Spw is not limited to the example indicating the presence or absence of the operation of each unit in the copying machine 1, and may be a signal indicating the power consumption itself of the load circuit. Further, the number of switching FETs in the switching power supply circuit 200 may be four or more, and the number of FETs to be switched may be finely controlled. Further, the number of switching FETs may be two. The switching power supply circuit 200 is not limited to the example applied to the image forming apparatus, and may be applied to other electrical devices.

1 is a side view schematically showing an internal configuration of a copying machine as an example of an image forming apparatus using a switching power supply circuit according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating an example of an electrical configuration of the copier illustrated in FIG. 1. FIG. 3 is a circuit diagram illustrating an example of a configuration of a switching power supply circuit illustrated in FIG. 2. FIG. 2 is an explanatory diagram for explaining an example of an operation of the copier shown in FIG. 1. It is a circuit diagram which shows the switching power supply circuit which concerns on background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copy machine 3 Post-processing part 4 Image formation part 5 Original reading part 10 Control part 11 Image formation control part 12 Power saving control part 13 Operation | movement state transmission part 40 Image formation part 41 Transfer roller 42 Exposure apparatus 43 Photosensitive drum 44 Developing apparatus 45 Fixing section 46 Paper transport section 47 Operation panel 200 Switching power supply circuit 201, 202, 203, 204 Connection terminal 205 Switching control section 471 Start button 472 Power saving key Q1, Q2, Q3 FET
Spw signal

Claims (7)

A switching power supply circuit that generates a desired voltage by repeating current switching and outputs the voltage to a load circuit,
A plurality of switching elements connected in parallel to each other for switching the current;
A power information acquisition unit that acquires power information related to the amount of power required by the load circuit;
The switching operation of the plurality of switching elements such that the larger the amount of power indicated by the power information acquired by the power information acquisition unit, the greater the number of switching elements used for the switching among the plurality of switching elements. And a switching control unit for controlling the switching power supply circuit. The load circuit has a plurality of operating states with different power consumption,
The switching power supply circuit according to claim 1, wherein the power information acquisition unit acquires information indicating an operation state of the load circuit as the power information. The switching power supply circuit according to claim 2, wherein the load circuit includes, as the plurality of operation states, a normal mode in which a normal operation is performed and a power saving mode in which power consumption is lower than that in the normal mode. The plurality of switching elements are FETs;
The gate of each said FET is connected to the said switching control part through the parallel circuit of the diode for gate charge discharge, respectively, respectively, and resistance, The Claim 1 characterized by the above-mentioned. Switching power supply circuit. A switching power supply circuit according to claims 1 to 4,
The load circuit;
An operation state transmission unit that transmits information indicating the operation state to the power information acquisition unit as the power information;
The load forming circuit includes an image forming unit that forms an image on a sheet. The load circuit further includes a reading unit that reads an image from a document,
The operating state transmitting unit further includes:
The image forming apparatus according to claim 5, wherein information indicating an operation of the reading unit and an operation of the image forming unit is transmitted as the power information to the power information acquisition unit. The switching controller is
In the information indicating the operation of each unit indicated by the power information received by the power information acquisition unit, the number of switching elements used for the switching increases as the number of operating parts increases. The image forming apparatus according to claim 6, wherein a switching operation of the element is controlled.

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