JP2012226048A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the power supply as stable as possible to an external device connected to an outlet part even when the external device other than a dedicated optional device is connected to the outlet part.SOLUTION: An image forming apparatus including an outlet 87 connectable to an external device is capable of supplying a power supplied from an AC power source to the external device connected to the outlet 87. The image forming apparatus comprises: a current sensor 82 for detecting a current consumed by the external device connected to the outlet 87; and a power source control part 85 for controlling to decrease a current consumed for performing an image forming operation with the increasing current value detected by the current sensor 82.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a laser printer, and a facsimile machine that includes a heating device for heating a toner image on a recording material.

  Conventionally, for example, in Patent Document 1, the total current consumption of a copying machine is detected, and in the copying machine, in the fixing heater, the sum of the power consumption of the fixing heater of the heating device and other loads is less than the allowable power of the power source. Controlling power consumption is disclosed.

  By the way, when connecting optional equipment that needs to supply power exclusively to the main body of the image forming apparatus (hereinafter simply referred to as the main body), to reduce the AC bundling that is inserted into the commercial outlet, the main body passes through the outlet section. May supply power to optional equipment. The device connected to the outlet section is a value obtained by subtracting the maximum current consumption value (for example, 10A) of the main body from the rated current value of the commercial outlet (for example, generally 15A in Japan) (for example, 5A (= 15A-10A)) Can be used.

JP 58-105180 A

  However, any external device can be connected if the outlet has a shape. For this reason, when an external device other than a dedicated optional device that exceeds the rated current value minus the maximum current consumption of the main unit is connected to the outlet, the rated current value of the commercial outlet may be exceeded. is there. Also, in such a case, if the device connected to the outlet is operating during the image forming operation of the main unit, the rated current value of the commercial outlet will be exceeded, and the breaker will fall, resulting in the product being imaged. May also have an effect. Furthermore, when the device connected to the outlet is an information device such as a computer, information in the information device may be lost when the power supply is stopped.

  The present invention has been made under such circumstances, and even when an external device other than a dedicated optional device is connected to the outlet portion, the power supply to the external device connected to the outlet portion is maintained as much as possible. With the goal.

  In order to solve the above-described problems, the present invention has the following configuration.

  (1) An image forming apparatus having an outlet unit to which an external device can be connected and capable of supplying electric power supplied from an AC power source to an external device connected to the outlet unit. Detection means for detecting a current consumed by the connected external device; and a control means for controlling to reduce a current consumed for performing an image forming operation as the value of the current detected by the detection means increases. An image forming apparatus comprising:

  According to the present invention, even when an external device other than the dedicated optional device is connected to the outlet unit, the power supply to the external device connected to the outlet unit can be maintained as much as possible.

Sectional view of image forming apparatus of embodiment FIG. 3 is a control block diagram of the fixing device according to the embodiment, and a diagram illustrating changes in fixing supply power and fixing temperature in each state of warm-up, standby, and image formation. Block diagram of the power supply unit of the embodiment Flow chart of main body operation control of embodiment

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail by way of examples with reference to the drawings.

[Configuration of electrophotographic color copier]
FIG. 1 is a schematic cross-sectional view showing the overall configuration of an electrophotographic color copying machine which is an example of an image forming apparatus of this embodiment. The electrophotographic color copying machine of the present embodiment is a color image output apparatus in which a plurality of image forming units are arranged in parallel and an intermediate transfer method is adopted, which is considered to be applied particularly effectively. The electrophotographic color copying machine of this embodiment includes an image reading unit 1R and an image output unit 1P. The image reading unit 1R optically reads a document image and outputs a recorded image signal converted into an electric signal to the image output unit 1P. The image output unit 1P includes a plurality of image forming units 10 (10a, 10b, 10c, 10d; hereinafter a to d are omitted) arranged in parallel in the present embodiment, and a paper feeding unit 20. The image output unit 1P includes an intermediate transfer unit 30, a fixing unit 40, a cleaning unit 50, a photo sensor 60, a control unit 70, and a power supply unit 80. In addition, a sheet feeding unit 90, which is a dedicated optional device, can be connected to the image output unit 1P.

  Further, each unit will be described in detail. Each image forming unit 10 has the same configuration. In each image forming unit 10, a drum-shaped electrophotographic photosensitive member as a first image carrier, that is, a photosensitive drum 11, is rotatably supported in the direction of the arrow. Driven by rotation. A primary charger 12, an optical system 13, a folding mirror 16, a developing device 14, and a cleaning device 15 are arranged in the rotational direction facing the outer peripheral surface of the photosensitive drum 11. The primary charger 12 applies a uniform charge amount to the surface of the photosensitive drum 11. Next, the optical system 13 irradiates light beams such as laser beams (broken lines a to d in the figure) modulated according to the recording image signal from the image reading unit 1R onto the photosensitive drum 11 via the folding mirror 16. By exposing, an electrostatic latent image is formed on the photosensitive drum 11. Further, the electrostatic latent image is visualized and a visible image is formed by the developing devices 14 each containing developer of four colors such as yellow, cyan, magenta and black (hereinafter referred to as “toner”). The visualized visible image is transferred to an intermediate transfer belt 31 that is a belt-like intermediate transfer member as a second image carrier that constitutes the intermediate transfer unit 30 with the image transfer regions Ta, Tb, Tc, and Td. The This is called primary transfer. The intermediate transfer unit 30 will be described in detail later. On the downstream side of the image transfer areas Ta to Td, the surface of the photosensitive drum 11 is cleaned by scraping off toner remaining on the photosensitive drum 11 without being transferred to the intermediate transfer belt 31 by the cleaning device 15. By the process described above, image formation with each toner is sequentially performed.

  The paper feed unit 20 includes cassettes 21a and 21b for storing the transfer material P (recording material), and pickup rollers 22a and 22b for feeding the transfer material P from the cassettes 21a and 21b one by one. Further, the paper feed unit 20 has a paper feed roller pair 23 and a paper feed guide 24 for further transporting the transfer material P sent out from the respective pickup rollers 22a and 22b. Further, the paper feed unit 20 includes a registration roller pair 25 for sending the transfer material P to the image transfer area Te in accordance with the image formation timing of each image forming unit 10. The paper supply unit 90, which is a dedicated option device, is an externally connected unit that can transport the transfer material P to the main body in addition to the cassettes 21a and 21b. The power supply to the paper feeding unit 90 is from the outlet 87 (outlet section).

  The intermediate transfer unit 30 will be described in detail. The intermediate transfer belt 31 is stretched and wound between a driving roller 32, a driven roller 33, and a secondary transfer counter roller 34. Here, the driving roller 32 transmits driving to the intermediate transfer belt 31. The driven roller 33 operates as a tension roller that applies an appropriate tension to the intermediate transfer belt 31 by urging a spring (not shown), and is driven by the rotation of the intermediate transfer belt 31 (in the direction of arrow B). A primary transfer plane A is formed between the driving roller 32 and the driven roller 33. The drive roller 32 is rotationally driven by a DC brushless motor (not shown). In the image transfer regions Ta to Td where the photosensitive drums 11 and the intermediate transfer belt 31 face each other, a primary transfer charger 35 is disposed on the back of the intermediate transfer belt 31. On the other hand, a secondary transfer roller 36 is disposed opposite to the secondary transfer counter roller 34 to form an image transfer region Te that is a nip portion with the intermediate transfer belt 31. The secondary transfer roller 36 is pressed against the intermediate transfer belt 31 with an appropriate pressure. The toner image on the intermediate transfer belt 31 is transferred to the transfer material P in the image transfer region Te. This is called secondary transfer. A cleaning unit 50 for cleaning the image forming surface of the intermediate transfer belt 31 is disposed downstream of the image transfer region Te of the intermediate transfer belt 31. The cleaning unit 50 includes a cleaning blade 51 for removing toner on the intermediate transfer belt 31, and a residual toner box 52 for storing toner remaining on the intermediate transfer belt 31.

  The fixing unit 40 includes fixing rollers 403 and 407 and pressure rollers 404 and 408 that are pressed against the fixing rollers 403 and 407. Further, a conveyance guide 43 for guiding the transfer material P to the nip portion between the fixing rollers 403 and 407 and the pressure rollers 404 and 408 is provided. The fixing unit 40 further includes an inner discharge roller 44, an outer discharge roller 45, and a transfer material for guiding the transfer material P discharged from the fixing rollers 403 and 407 and the pressure rollers 404 and 408 to the outside of the apparatus. A paper discharge tray 48 on which P is stacked is provided.

[Operation of electrophotographic color copier]
Next, the operation of the electrophotographic color copying machine will be described. The control unit 70 includes a CPU (not shown), a registration correction circuit, a motor driver unit, and the like for controlling the operation of the mechanism in each unit described above. When an image forming operation start signal is issued from the CPU, the sheet feeding operation is started from the sheet feeding stage of the sheet feeding unit 20 selected according to the selected sheet size or the like. For example, a case where paper is fed from the upper paper feed stage of the paper feed unit 20 will be described. First, the transfer material P is sent out one by one from the cassette 21a by the pickup roller 22a. Then, the transfer material P is guided between the paper feed guides 24 by the paper feed roller pair 23 and conveyed to the registration roller pair 25. At this time, the registration roller pair 25 is stopped, and the leading edge of the transfer material P hits the nip portion of the registration roller pair 25. Thereafter, the image forming unit 10 starts an image forming operation at a timing when a photo sensor 60 detects a mark (not shown) written in the intermediate transfer belt 31. Also, the registration roller pair 25 starts rotating in accordance with the timing. The rotation timing is set so that the transfer material P and the toner image primarily transferred onto the intermediate transfer belt 31 by the image forming unit 10 coincide in the image transfer region Te. A plurality of marks may be used.

  On the other hand, the image forming unit 10 operates as follows when an image forming operation start signal (ITOP), which is a mark detection signal output by the photosensor 60 detecting a mark, is issued. That is, the toner image formed on the photosensitive drum 11d that is the most upstream in the rotation direction of the intermediate transfer belt 31 by the above-described process is intermediated in the image transfer region Td by the primary transfer charger 35d to which a high voltage is applied. The image is transferred to the transfer belt 31. The transferred toner image is conveyed to the next image transfer region Tc. In this case, image formation is performed with a delay by the time during which the toner image is conveyed between the image forming units, and the next toner image is transferred with the position aligned on the previous image. Thereafter, the same process is repeated, and eventually, four color toner images are transferred onto the intermediate transfer belt 31 in a superimposed manner. Thereafter, when the transfer material P enters the image transfer region Te and contacts the intermediate transfer belt 31, a high voltage is applied to the secondary transfer roller 36 in accordance with the passing timing of the transfer material P. As a result, the four color toner images formed on the intermediate transfer belt 31 by the process described above are transferred onto the surface of the transfer material P. Thereafter, the transfer material P is accurately guided to the fixing unit 40 by the conveyance guide 43. The unfixed toner image is fixed on the surface of the transfer material P (on the recording material) by the heat of the fixing roller 403, the pressure roller 404, the fixing roller 407, and the pressure roller 408 and the pressure of the nip portion. Thereafter, the transfer material P is conveyed by the inner discharge roller 44 and the outer discharge roller 45, discharged outside the apparatus, and stacked on the discharge tray 48.

[Configuration of fixing unit]
FIG. 2A is a diagram showing details of the fixing unit 40 of this embodiment. The motor 401 drives the fixing roller 403 in the direction of the arrow. The driving of the fixing roller 403 is transmitted to the belt 405 and the belt 405 also rotates. The fixing roller 407 applies tension to the belt 405 and is driven by the driving force transmitted from the belt 405. Similarly, the motor 402 drives the pressure roller 404 in the direction of the arrow. The driving of the pressure roller 404 is transmitted to the belt 406 and the belt 406 also rotates. The pressure roller 408 applies tension to the belt 406 and is driven by the drive transmitted from the belt 406. The motor 402 rotates in synchronization with the motor 401. Pressure is applied between the fixing roller 403 and the pressure roller 404 and between the fixing roller 407 and the pressure roller 408. The pressure pads 409 and 410 are arranged so as to face the inner surfaces of the belt 405 and the belt 406, and pressure is applied thereto. Due to these pressures, a pressure is generated between the belt 405 and the belt 406. The belts 405 and 406 are configured by forming a surface layer of silicone rubber on a metal (for example, Ni). The pressure rollers 404 and 408 are driven by the motor 402, but may be configured to be driven by the motor 401 via a gear or the like.

  The belt 405 is locally heated by a heating device 412 above the fixing roller 407. The heated area of the belt 405 is rotated by the belts 405 and 406 so that the entire fixing device (belts 405 and 406, fixing rollers 403 and 407, pressure rollers 404 and 408; Heat). The control unit 70 controls the amount of power supplied from the fixing power source 415 to the heating device 412 according to the result of temperature detection by a temperature detection sensor 414 such as a thermistor provided on the surface of the belt 405, thereby fixing the fixing device. The whole is controlled to a predetermined temperature. The heating device 412 is, for example, an electromagnetic induction heating method, and a coil is disposed, and an alternating current is passed through the coil to generate a magnetic field, whereby the belt 405 that is a conductive heating element self-heats. The heating device 412 consumes a maximum amount of power of, for example, 800 W during startup (warm-up) immediately after power-on, 600 W during image formation, and 400 W during standby. The power at the time of start-up is the highest because the temperature is set to a predetermined temperature in as short a time as possible from the low temperature, and the power during standby is low because the power is supplied only to the heat retention of the fixing device. The amount of power supply varies depending on the heat capacity of the fixing device and the image forming speed. A thermo switch 413 is in contact with the belt 405 as a safety device for the fixing device. The thermo switch 413 cuts off the power supply to the fixing unit when the temperature of the contact portion with the belt 405 exceeds 250 ° C., for example. When the transfer material P on which an unfixed toner image is formed on the belt 405 and the belt 406 is conveyed in the direction of the arrow in the figure, the toner image on the transfer material P is fixed by heat and pressure.

[Changes in fixing temperature and fixing power supply]
FIG. 2B shows the transition of the detected temperature of the fixing device (fixing temperature) and the power supplied to the fixing device (fixing supply power) at each start-up (warm-up), standby, and image forming operation. FIG. The control unit 70 controls the amount of power to the heating device 412 while detecting the temperature by the temperature detection sensor 414. That is, the control unit 70 always supplies 800 W of electric power to the heating device 412 during the warm-up from the power-on (ON). When the temperature detection sensor 414 determines that the temperature of the fixing device has become equal to or higher than a predetermined temperature (for example, 190 ° C. in this embodiment), the control unit 70 transitions to a standby state (READY) and supplies power to the heating device 412. Reduce the amount to 400W. When the image forming operation starts (PRINT start), the transfer material P is deprived of heat by passing through the fixing device, and the temperature of the fixing device is lowered. For this reason, when the temperature detection sensor 414 detects that the temperature of the fixing device has fallen below a predetermined temperature (190 ° C.), the control unit 70 increases the amount of power supplied to the heating device 412 to 600 W. Thereafter, when the temperature detection sensor 414 detects that the fixing device has reached a predetermined temperature (190 ° C.) or higher, the control unit 70 again reduces the amount of power supplied to the fixing device to 400 W. In this way, the control unit 70 maintains the fixing device at a predetermined temperature by switching the amount of power supplied to the heating device 412 according to the temperature detected by the temperature detection sensor 414.

  There is an upper limit for the current that can be consumed from a commercial outlet (for example, a typical outlet in Japan is 15A), and therefore the upper limit of power that can be consumed by the entire copier is determined. For example, if the upper limit is 1000 W, it is necessary to supply 200 W as the amount of power required for the drive systems of the motors 401 and 402 and the like during warm-up, and the upper limit of the amount of power that can be supplied to the fixing device is 800 W. Further, since 400 W is required for the fixing unit during standby and 150 W is necessary for the other power, there is a margin of 450 W (= 1000− (400 + 150)). At the time of image formation, the number of motors that drive the transfer material is increased, and the amount of electric power required for others increases to 400W. During image formation, 600 W is supplied to the fixing device when the temperature of the fixing device becomes a predetermined temperature or lower, so that the power consumption is an upper limit of 1000 W (= 400 + 600). On the other hand, since 400 W is supplied to the fixing device when the temperature of the fixing device exceeds a predetermined temperature, there is a margin of 200 W (= 1000− (400 + 400)) up to the upper limit of the fixing device 400 W + other 400 W. As described above, the amount of power consumed by the entire copying machine varies depending on the operation state of the copying machine.

[Power supply unit]
FIG. 3 is a diagram showing details of the power supply unit 80 in the present embodiment. The AC power supplied from the commercial AC power source via the power cord is supplied to the main body sub power source 84 via the switch (SW1) 81. The AC power supplied from the power cord is also supplied to the main body main power supply 86 via the switch (SW1) 81 and the switch (SW2) 83. Furthermore, AC power supplied from the power cord is also supplied to the outside via the current sensor 82 and the outlet 87. The main body sub power source 84 and the main body main power source 86 convert AC power supplied from an outlet into DC power having a predetermined DC voltage. The main body sub power source 84 supplies the converted DC power to the power source control unit 85, the control unit 70, and an operation unit (not shown). The main body main power supply 86 supplies the converted DC power to each unit in the image output unit 1P excluding the image reading unit 1R and the control unit 70. The switch (SW1) 81 is opened / closed by the power supply controller 85 in accordance with the value of the current sensor 82. The current sensor 82 detects the current consumption of the external device connected to the outlet 87 and outputs, for example, an analog signal corresponding to the current value to the power control unit 85. The power controller 85 reads the analog signal input from the current sensor 82 with an AD converter (not shown) or the like. The switch (SW2) 83 also opens and closes according to the current value of the current sensor 82.

  Next, the operation of the power control unit 85 will be described. The power control unit 85 performs opening / closing control of the switches 81 and 83 according to the current value of the current sensor 82 and instructs the control unit 70 to change the main body operation control and the fixing operation control.

[Operation of power control unit]
FIG. 4 is a flowchart for performing main body operation control according to the detection result of the current sensor 82 and opening / closing control of the switches 81 and 83. This flowchart is executed by the power control unit 85. In this flow, the main body operation is limited so that the operation of the external device connected to the outlet 87 is given priority. There is a possibility that the outlet 87 may be connected to an outlet 87 that may destroy data in the storage device when the supply of power is stopped during operation. On the other hand, since the image forming apparatus can operate while restricting the operation, the image forming apparatus performs control so that the external device connected to the outlet 87 is given priority. That is, the power supply control unit 85 controls to reduce the current consumed for performing the image forming operation as the value of the current detected by the current sensor 82 increases. In this embodiment, the rated current of the commercial outlet is 15A, and the maximum current consumption of the image forming apparatus main body (hereinafter also simply referred to as the main body) is 10A. Therefore, the case where the current that can be normally supplied to the outlet 87 is 5 A (= 15 A−10 A) will be described as an example.

  In step (hereinafter referred to as “S”) 1, the power supply controller 85 determines that the current consumed by an external device connected to the outlet 87 (hereinafter referred to as “outlet consumption current”), that is, the detected current value of the current sensor 82 is 5 A (first). It is determined whether or not it is equal to or greater than a predetermined value. When the power supply control unit 85 determines in S1 that the outlet current consumption value detected by the current sensor 82 is less than 5 A, the power supply control unit 85 instructs the control unit 70 in S2 to be in a normal operable state. Here, the normal operation means that a normal image forming operation can be performed at the time of image formation without limiting the image forming operation. In this case, since the outlet current consumption value is less than 5 A, even if the main body consumes the maximum current consumption 10 A, it does not exceed the rated current 15 A of the commercial outlet. After the process of S2, the power supply control unit 85 returns to the process of S1 in order to detect the current consumption of the outlet 87 by the current sensor 82 at all times.

  If the power supply control unit 85 determines in S1 that the outlet current consumption value detected by the current sensor 82 is 5 A or more, the process proceeds to S3. In this case, since the outlet current consumption value is 5 A or more, when the main body consumes the maximum current consumption 10 A, the rated current of the commercial outlet is 15 A or more. Therefore, the power supply controller 85 determines whether or not the outlet current consumption value is 7A (second predetermined value) or more in S3. When determining that the outlet consumption current value detected by the current sensor 82 is less than 7 A in S3, the power supply control unit 85 instructs the control unit 70 to enable the image forming operation with operation restriction in S4. Here, the operation restriction refers to prohibition of reading operation of the image reading unit 1R that can save power consumption of electric parts such as a motor, and prohibition of automatic double-sided image forming operation, and other image forming operations are possible. To do. That is, the current consumed on the main body side is reduced and the amount is supplied to the external device connected to the outlet 87. Note that the current value consumed when the main body prohibits the reading operation of the image reading unit 1R and the automatic double-sided image forming operation is, for example, 8A. Therefore, when such a restriction is performed, the current that can be consumed by the outlet 87 is 7A (= 15A-8A). For this reason, the power supply control unit 85 makes a determination using a value of 7A in S3. After the process of S4, the power controller 85 returns to S1 in order to detect the current consumption of the outlet 87 by the current sensor 82 at all times.

  If the power supply control unit 85 determines in S3 that the outlet consumption current value detected by the current sensor 82 is 7A or more, the process proceeds to S5. In this case, since the outlet current consumption value is 7 A or more, even if the main body prohibits the reading operation or the automatic double-sided image forming operation, the current consumption is 8 A, and the rated current of the commercial outlet is 15 A or more. Therefore, the power supply control unit 85 determines whether or not the outlet consumption current value detected by the current sensor 82 in S5 is 8A (third predetermined value) or more. If the power supply control unit 85 determines in S5 that the outlet consumption current value detected by the current sensor 82 is less than 8A, it performs the process of S6. In S6, the power control unit 85 instructs the control unit 70 to reduce the fixing supply power and reduce the productivity to enable the image forming operation (printing operation) and to perform the operation restriction similarly to S4. Note that productivity means the number of printed sheets per unit time (for example, per minute). The power supply control unit 85 performs control for reducing (down) fixing supply power via the control unit 70, for example. For example, the power supply control unit 85 normally supplies 800 W to the fixing device during warm-up, but in S6, the power supplied to the fixing device is reduced to 600 W, and the power supplied to the maximum 600 W during image formation is 400 W. To do. Here, if the power supplied to the fixing device at the time of image formation is 400 W, the temperature reduction of the fixing device cannot be compensated. Therefore, image formation is stopped while the fixing supply power is reduced, that is, fixing is performed by reducing productivity. Make up for the drop in power supply. Note that the current consumed by the main body when the fixing power is reduced and productivity is further reduced and the operation is further limited is, for example, 7 A. Therefore, when such a limitation is performed, the current that can be consumed by the outlet 87 is 8A (= 15A-7A). For this reason, the power supply control unit 85 makes a determination using a value of 8A in S5. After the process of S6, the power supply controller 85 returns to S1 in order to detect the current consumption of the outlet 87 by the current sensor 82 at all times.

  If the power supply control unit 85 determines in S5 that the outlet consumption current value detected by the current sensor 82 is 8A or more, the process proceeds to S7. In this case, since the outlet current consumption value is 8 A or more, the main body consumes 7 A even if the power supply for fixing is reduced and the productivity is reduced, and the operation is restricted, and the rated current of the commercial outlet is 15 A or more. End up. Therefore, the power supply controller 85 determines whether or not the outlet consumption current value detected by the current sensor 82 in S7 is 10 A (fourth predetermined value) or more. If the power supply control unit 85 determines in S7 that the outlet current consumption value detected by the current sensor 82 is less than 10A, it performs the process of S8. In S <b> 8, the power supply control unit 85 instructs the control unit 70 to display a display indicating that the image forming operation cannot be performed on an operation unit (not shown) and turns off the switch 83 to stop supplying power to the main body main power supply 86. That is, the power control unit 85 controls the control unit 70 to stop the image forming operation. In addition, since the current consumed when the power supply to the main body main power supply 86 is stopped is 5 A, for example, when such a restriction is performed, the current that can be consumed by the outlet 87 is 10 A (= 15 A-5 A). Become. For this reason, the power supply control unit 85 makes a determination using a value of 10A in S7.

  If the power supply control unit 85 determines in S7 that the outlet current consumption value detected by the current sensor 82 is 10 A or more, the process proceeds to S9. In this case, since the outlet current consumption value is 10 A or more, even if the power supply to the main body main power supply 86 is stopped, a current of 5 A is consumed, resulting in a commercial outlet rated current of 15 A or more. Therefore, the power supply control unit 85 turns off the switch 81 in S9, and stops the power supply to the main body main power supply 86 and the main body sub power supply 84. Since the image formation cannot be performed when the switch 81 is turned off, in order to use the image forming apparatus again, the current consumption of the outlet 87 is reduced or the external device connected to the outlet 87 is removed, and the image forming apparatus is disconnected. It is necessary to start up again.

  Since the power supply control unit 85 turns off the switch 83 in S8, the main body operation cannot be performed even if the outlet current consumption value detected by the current sensor 82 subsequently becomes 8A or less. Therefore, after the process of S8, the power supply control unit 85 determines in S10 whether the outlet current consumption value detected by the current sensor 82 is 8A or more. When the power supply control unit 85 determines in S10 that the outlet current consumption value detected by the current sensor 82 is not equal to or greater than 8A, the power control unit 85 turns on the switch 83 in S11 and displays an image forming operation possible display on an operation unit (not shown). Instruct the control unit 70 as follows. On the other hand, when the power supply control unit 85 determines in S10 that the outlet current consumption value detected by the current sensor 82 is 8A or more, the process proceeds to S7.

  As described above, in the present embodiment, when an external device having a current consumption value greater than or equal to the difference between the rated current value of the commercial outlet and the maximum current consumption value of the main body is connected to the outlet 87, the following processing is performed. . That is, the current consumption of the outlet 87 is detected by the current sensor 82, and the power control unit 85 performs image formation while restricting the image forming operation of the main body according to the detection result. Thus, according to the present embodiment, even when an external device other than the dedicated optional device is connected to the outlet 87, the power supply to the external device connected to the outlet 87 is maintained and the external device can be used. be able to.

  Note that the rated current value of the commercial outlet used in this embodiment is not limited to 15A, and may be other values such as 20A. Further, the maximum current consumption value of the image forming apparatus, the current consumption value when the reading operation or the automatic double-sided image forming operation is prohibited, and the current consumption value when the fixing supply power is reduced and the productivity is reduced are as follows: It differs depending on the model, and is not limited to the values used in this embodiment.

82 Current sensor 85 Power supply controller 87 Outlet

Claims (6)

An image forming apparatus having an outlet part to which an external device can be connected, and capable of supplying electric power supplied from an AC power source to the external device connected to the outlet part,
Detecting means for detecting a current consumed by an external device connected to the outlet unit;
Control means for controlling to reduce the current consumed to perform the image forming operation as the value of the current detected by the detection means increases;
An image forming apparatus comprising:   The control unit limits the image forming operation by reducing a current consumed for performing the image forming operation when the value of the current detected by the detecting unit is larger than a first predetermined value. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 2, wherein the image forming operation restricted by the control unit is a reading operation and an automatic double-sided image forming operation. A fixing means for fixing an unfixed toner image formed on the recording material;
The control means reduces the power supplied to the fixing means when the value of the current detected by the detection means is larger than a second predetermined value larger than the first predetermined value, and per unit time. 4. The image forming apparatus according to claim 2, wherein the number of printed sheets is reduced as compared with before the power supplied to the fixing unit is reduced.   5. The image forming operation according to claim 4, wherein the control unit stops the image forming operation when a current value detected by the detection unit is larger than a third predetermined value larger than the second predetermined value. The image forming apparatus described in 1.   6. The image forming apparatus according to claim 5, wherein the control unit stops the image forming apparatus when the value of the current detected by the detection unit is larger than a fourth predetermined value larger than the third predetermined value. The image forming apparatus described in 1.

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