JP2007047556A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a power consumption of almost zero W by stopping the switching power supply of an image forming apparatus, during standby. <P>SOLUTION: The image forming apparatus has a converter for converting a commercial power supply voltage into a DC voltage, an interface section for connecting to an external equipment and an electric storage means for storing electric power. In addition, the image forming apparatus has a control means for stopping the converter after a predetermined time lapses in an image forming standby state and a restart means for restarting the converter by using the electric power stored in the electric storage means. When the converter is stopped, the electric power stored in the electric storage means is supplied to the restart means, to restart the converter, with a predetermined signal transmitted through the interface section from the external equipment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic process or the like and a fixing unit thereof.

<Schematic Configuration of Laser Beam Printer 100>
FIG. 7 is a diagram showing a schematic configuration of a tandem type laser beam printer 100 which is an example of an image forming apparatus targeted by the present invention. The laser beam printer 100 is a so-called tandem type printer in which an image forming unit is provided for each color of a black image (Bk), a yellow image (Y), a magenta image (M), and a cyan (C) image.

  Each image forming unit includes a photosensitive drum 18, a primary charger 16 for uniformly charging the photosensitive drum, a scanner unit 11 for forming a latent image on the photosensitive drum, and developing the latent image into a visible image. The developing unit 14, a transfer unit 19 that transfers a visible image onto transfer paper, a cleaning device 15 that removes residual toner on the photosensitive member, and the like.

  Here, the configuration of the scanner unit 11 will be described.

  FIG. 8 is a diagram showing the configuration of the scanner unit 11.

  When there is an image formation instruction from an external device (not shown) such as a personal computer, a controller (not shown) in the laser beam printer 100 outputs an image signal (image signal for turning on / off a laser beam as exposure means). VDO signal) 101. This image signal (VDO signal) 101 is input to the laser unit 102 in the scanner unit 11. Reference numeral 103 denotes a laser beam that is on / off modulated by the laser unit 102. Reference numeral 104 denotes a scanner motor that regularly rotates a rotary polygon mirror (polygon mirror) 105. An imaging lens 106 focuses the laser beam 107 changed by the polygon mirror on the photosensitive drum 18 that is the surface to be scanned.

  With this configuration, the laser beam 13 modulated by the image signal 101 performs horizontal scanning (scanning in the main scanning direction) on the photosensitive drum 18, and a latent image is formed on the photosensitive drum 18.

  Reference numeral 109 denotes a beam detection port, which takes in a beam from a slit-shaped entrance port. The laser beam entering from the entrance is guided to the photoelectric conversion element 111 through the optical fiber 110. The laser beam converted into an electric signal by the photoelectric conversion element 111 is amplified by an amplifier circuit (not shown) and then becomes a horizontal synchronization signal.

  Returning to FIG. The transfer sheet as a recording medium fed from the cassette 22 stands by at the registration roller 21 in order to take timing with the image forming unit.

  A registration sensor 24 for detecting the leading edge of the fed transfer paper is provided in the vicinity of the registration roller 21. An image formation control unit 316 (see FIG. 1) that controls the image forming unit detects the timing at which the leading edge of the paper reaches the registration roller 21 based on the detection result of the registration sensor 24, and detects the first color (yellow in the example in the figure). An image is formed on the photosensitive drum 18a, which is an image carrier, and the heater (not shown) temperature of the fixing device 23 is controlled to a predetermined temperature.

  Reference numeral 29 denotes a suction roller, which applies a suction bias to the shaft of this roller and electrostatically sucks the transfer paper onto the transport belt 20.

  The transfer paper waiting on the registration roller 21 is conveyed on the transfer belt 20 arranged so as to penetrate each color image forming portion, taking the timing of the detection result of the registration sensor 24 and the image forming process, and the transfer device. The first color image is transferred onto the transfer paper by 19a.

  Similarly, the image of the second color (magenta in the example in the figure) is obtained by taking the timing of the detection result of the registration sensor 24 and the process of forming the second color image on the transfer sheet conveyed on the transfer belt 20. It is superimposed and transferred onto the image. Similarly, the image of the third color (cyan in the example in the figure) and the image of the fourth color (black in the example in the figure) are sequentially superimposed and transferred onto the transfer paper at the timing of each image forming process.

  Then, the transfer paper on which the toner image is transferred is conveyed to the fixing device 23, and the transfer paper passes through a nip portion N (details will be described later) in the fixing device 23, whereby the toner is pressurized and heated. It is fused and fixed on transfer paper. The transfer paper that has passed through the fixing device 23 is discharged out of the apparatus, and full-color image formation is completed.

  FIG. 9 is a block diagram showing the configuration of a conventional switching power supply circuit unit of the image forming apparatus.

  Here, the configuration of a conventional switching power supply circuit unit will be described with reference to FIG.

  A conventional switching power supply 700 includes a rectifier circuit 704 and a DC-DC converter 705. The commercial power supply 621 supplies an AC voltage to the rectifier circuit 704 by turning on the seesaw type power switch 701. The rectifier circuit 704 rectifies the AC voltage of the commercial power supply into a DC voltage. Reference numeral 705 denotes a DC-DC converter having a built-in switching element (not shown), which steps down and outputs the DC voltage rectified by the rectifier circuit to a DC voltage V used in the image forming apparatus.

<Technology trends>
2. Description of the Related Art Image forming apparatuses using an electrophotographic process such as a laser beam printer are provided with a fixing device that heats and fixes a toner image formed on a recording medium (recording paper, OHP sheet, etc.). There are several types of heating systems in this fixing device. In particular, the ceramic sheet heating heater system with a heater pattern formed on a substrate such as ceramics can directly heat the fixing nip via a film, and fixing using a heat roller system using a halogen lamp as a heat source. This is advantageous in that a fixing process with higher efficiency than that of the apparatus can be achieved.

  As another type, the electromagnetic induction heating method in which current is induced in the fixing roller by magnetic flux and heat is generated by the Joule heat, the fixing roller can be directly heated by using the generation of induced current, and the ceramic surface As with the heat generating heater method, it is possible to achieve a fixing process that is more efficient than a heat roller type fixing device.

  By the way, for example, in a color image forming apparatus (A4 machine) capable of printing A4 size standard paper at a speed of 16 sheets / minute, in recent years, a fixing device having a small heat capacity of the above-described ceramic sheet heater type is used. This eliminates the need for standby fixing temperature adjustment (hereinafter, “temperature adjustment” may be abbreviated as “temperature adjustment”) and realizes so-called “on-demand fixing” in which heating is performed only during printing. It is possible.

  On the other hand, in a color image forming apparatus (A3 machine) capable of printing up to A3 size standard paper, although it depends on the printing speed, since the heat capacity required for the fixing device is generally larger than that of the A4 machine, Also in the above, so-called “standby temperature control” is performed in which preheating is performed by supplying power to the fixing device at predetermined time intervals. The reason for performing standby temperature control is as follows.

  FIG. 10 shows the rise from the cold state of the fixing device to the temperature ready for printing (for example, 180 ° C.) in the color image forming apparatus (A3 machine) using the conventional ceramic sheet heater type fixing device. It is a figure which shows the outline | summary of the relationship between time and the electric power (fixing electric power) supplied to the heater of the fixing device at that time.

  In the figure, assuming that the fixing power that can be supplied is about 900 W, the rise time until reaching the temperature of the printable state (printing temperature) is 30 sec (point Wa). This time is extremely short compared with a fixing device using a generally used halogen heater. However, considering the paper transport time, the time from the start of printing until the first image-formed paper is discharged to the paper discharge unit (first print out time) is later than 30 sec, and the user is kept waiting. End up.

  For this reason, in order to shorten the first printout time, the power is fixed at predetermined time intervals even during standby (as is generally done in an image forming apparatus using a halogen heater type fixing device). Preheating is performed by supplying to the vessel. By performing this standby temperature control, a predetermined fixing temperature at which an image can be formed is quickly reached after a print job is started.

  The power consumption during standby temperature adjustment in the ceramic sheet heater method can be set to a lower temperature compared to the fixing method using a halogen heater, so the power consumption during the standby temperature adjustment can be reduced. However, when compared with the on-demand fixing method, an extra power (power during standby temperature control) is still required.

  By the way, in this image forming apparatus, if the power supplied to the heater of the fixing device can be increased by about 200 W, 1100 W can be supplied to the fixing device, and the time required to reach the printing temperature is about 15 seconds (in the drawing). Point Wb). For this reason, if the first printout time targeted by the image forming apparatus is about 20 seconds (depending on the configuration of the image forming apparatus, the paper conveyance path, the conveyance speed, etc.), the on-state temperature control that does not require standby temperature control is enabled. It is also possible to realize demand fixing.

  Recently, however, as the technology of image forming apparatuses has improved, image forming apparatuses in the category of medium speed machines (intermediate machines) have been speeded up while being downsized and reduced in price. Has reached. Along with this, added value such as energy saving and shortening the first printout time has been increasingly demanded from the market.

  In consideration of such a background, even if a high-efficiency ceramic sheet heating heater type fixing device is used, it is difficult to meet market demands with on-demand fixing that could be realized with the conventional A4 machine. Yes.

  Further, as described above, the standby temperature control that has been conventionally performed in the A3 machine is that the power is supplied to the fixing device even in the standby state even though it is the minimum necessary power. This is one of the factors that make it difficult to reduce power consumption during standby of the image forming apparatus.

  However, if this standby temperature adjustment control is not performed with emphasis on energy saving during standby, it takes a long time to reach a predetermined fixing temperature at which image formation is possible from the start of printing. You will face the problem of slow printout time. That is, there is a trade-off between energy saving during standby and shortening of the first printout time.

  Therefore, it is necessary to develop an on-demand fixing system that can be accepted in the market and has a fast rise in temperature while balancing energy saving during standby and shortening the first printout time.

  On the other hand, large-scale and high-value-added image forming devices such as monochrome high-speed printers and color printing high-quality printers, so-called high-speed machines (high-end machines), have been devised to save energy, but have high functionality and optional equipment. There is a demand for further added value such as enhancement of power consumption, and power consumption is increasing. One guideline for the upper limit of power consumed by these devices is the maximum current that can be supplied by commercial power.

  For example, if a maximum supply current of 15 A is specified for a commercial power supply with a voltage of 100 V, the upper limit of the power is 1500 W (= 100 V × 15 A). The image forming apparatus main body is usually designed so that the maximum current of the apparatus does not exceed the maximum current of the commercial power source.

  Further, in this high speed machine class fixing device, a fixing device having a large heat capacity is generally used so as to withstand high speed continuous fixing. The disadvantage of such a fuser is that it takes a long time (several minutes) to reach the standby temperature (warm-up time) from the cold state of the fuser, and this shortens the warm-up time. It was one of the improvement issues.

  On the other hand, if you try to reduce the warm-up time of the fuser simply by turning on a large amount of power, the maximum power of the commercial power supply will be limited by the upper limit of the power that can be used as a device. Unless done, it was difficult to further reduce the warm-up time.

  As one means for solving such a problem, for example, in Patent Document 1, a power storage unit is provided in an image forming apparatus including a main heater and a sub-heater in a fixing unit in order to effectively use power to the fixing unit. It has been proposed that the power storage unit is selectively connected to a DC power source or a DC motor control unit. That is, while power is being supplied from the power storage unit to the DC motor, the power to be supplied to the DC motor can be supplied to the sub-heater, so that the temperature of the fixing device can be raised compared to the conventional case. It can be copied.

  Japanese Patent Application Laid-Open No. 2004-26883 discloses a method for saving energy and shortening a print start time by providing a power storage device in an image forming apparatus and using both power from a commercial power source and power from the power storage device when the fixing unit is started up. Proposed.

  On the other hand, even if standby temperature control is achieved by on-demand fixing, to achieve further energy saving, the power consumption of the image formation control unit, etc. must be reduced during standby and in power saving mode. .

  Unlike an image forming apparatus for personal use, an image forming apparatus connected to a network has a long time during which the power switch is always on and in a standby state. In general, when the image forming apparatus is on standby, the image forming control unit operates in a standby state, and when the image forming apparatus is not an on-demand fixing device, the fixing device is warmed by standby temperature control of the fixing device, so that a large amount of power is consumed. Accompany. For this reason, in order to reduce power consumption further than in the standby state, a low power consumption mode is provided in which standby temperature adjustment of the fixing device is stopped and most of the functions of the image forming apparatus are stopped as much as possible.

  However, a small amount of power (for example, several watts) is consumed due to power consumption in these image forming apparatuses and switching loss in a switching power supply (hereinafter referred to as power supply) that supplies power to the image forming apparatus. Considering that there are hundreds of thousands of image forming apparatuses sold and the unit of the year when these image forming apparatuses are in operation, this small amount of power consumption is equivalent to a large amount of power consumption on a yearly basis on a global scale. .

  From this point of view, in order to reduce power consumption during standby, Patent Document 3 provides a main power supply unit and a sub power supply, and power is consumed by the main power supply by supplying power from the sub power supply to the control unit during power saving. It has been proposed to reduce the power and turn on the main power supply by an operation signal from an external device.

Further, in Patent Document 4, in a device configuration having a master-slave relationship, a proposal is made to stop the power supply of a slave device during power saving and to start the power supply of the slave device by the startup power from the master device. ing.
Japanese Utility Model Publication No. 7-41023 JP 2002-174988 A JP-A-7-115484 JP 2002-323941 A

  However, in Patent Document 3, although the power consumption of the main power supply is reduced at the time of low power consumption, the control portion and the sub power supply are not stopped, and thus it is difficult to further reduce the power consumption.

  Further, in Patent Document 4, the secondary device is stopped at the time of low power consumption, but if the power for activation cannot be supplied from the main device, the power of the secondary device is started. I can't. Considering this in the image forming apparatus, the main device can be considered as a personal computer, a LAN server or the like, and the sub device can be considered as an image forming device. When connected to an image forming apparatus using a USB port of a personal computer, power can be supplied via the USB port. Therefore, although the technology introduced in Patent Document 4 may be realized, personal An image forming apparatus connected to a computer on a one-to-one basis has many personal uses, and such an image forming apparatus can be expected to have a power switch turned off by a user during standby. That is, the power is turned on only when it is used.

  On the other hand, most image forming apparatuses used in general offices are often connected to a LAN network or the like. Although these networks can transmit image forming job signals and the like, unlike the USB port, it is difficult to supply power, so it is difficult to realize the technique introduced in Patent Document 4.

  Therefore, until the image formation job signal from the external device comes, the switching power supply is in the off state, the image formation job signal comes, and after the switching power supply is activated, the on-demand fixing device is activated. However, this is considered to be an ideal operation for reducing the power consumption of the image forming apparatus.

  The present invention has been made in view of such problems, and achieves a power consumption of approximately zero W by stopping the switching power supply of the image forming apparatus during standby, and the switching power supply without power supply from an external device. An object of the present invention is to provide an image forming apparatus that can start up the image forming apparatus and that consumes less power than before.

  In addition, in the case of an image forming apparatus in which a plurality of heating elements are provided in the fixing unit and the driving of the sub-heating element out of the main heating element and the sub-heating element is performed by a charging / discharging storage means, the storage means is switched. It is an object of the present invention to provide an image forming apparatus that can stop a switching power supply of an image forming apparatus at a standby time at a low cost without significant increase in cost by being used together with the activation of a power supply.

  The above problems are solved by the image forming apparatus of the present invention. A first aspect of the present invention is an image forming apparatus having a converter that converts a commercial power supply voltage into a DC voltage, an interface unit for connection to an external device, and a chargeable / dischargeable power storage unit that stores electric power. Control means for stopping the converter after elapse of a predetermined time in the image formation standby state, and a restart means for restarting the converter using the electric power stored in the power storage means are provided. According to a predetermined signal from an external device transmitted through the interface unit, the power stored in the power storage unit is supplied to the restart unit, and the converter is restarted.

  According to a second aspect of the present invention, there is provided a converter for converting a commercial power supply voltage into a DC voltage, an interface unit for connecting to an external device, chargeable / dischargeable power storage means for storing power, and the power storage means by a commercial power supply. In an image forming apparatus having a first charging means for charging, a control means for stopping the converter after elapse of a predetermined time in an image forming standby state, and a second charging means for charging the power storage means by a power generation means And a restarting means for restarting the converter using the electric power stored in the power storage means, and when the converter is stopped, according to a predetermined signal from an external device transmitted through the interface unit, The power stored in the power storage means is supplied to the restarting means, and the converter is restarted.

  According to a third aspect of the present invention, there is provided a converter for converting a commercial power source voltage into a DC voltage, an interface unit for connection to an external device, a chargeable / dischargeable power storage means for storing power, and a power supplied from the commercial power source. The first heating element that generates heat using the power and the second heating element that generates heat using the electric power stored in the power storage means are included, and the heat of the heating element is applied to the transfer material on which the toner image is formed. In addition, in an image forming apparatus having a fixing unit that fixes the toner image to the transfer material, a control unit that stops the converter after a predetermined time has elapsed in an image formation standby state, and the storage unit Restarting means for restarting the converter using electric power, and when the converter is stopped, a predetermined signal from an external device transmitted via the interface unit is used. Te, and supplies the electric power stored in said storage means to restart means and restarting the converter.

  According to the present invention, the switching power supply of the image forming apparatus is stopped at the time of standby, so that the power consumption is about zero W, and the switching power supply can be started without power supply from an external device. An image forming apparatus with low power consumption can be provided.

  In addition, in the case of an image forming apparatus in which a plurality of heating elements are provided in the fixing unit and the driving of the sub-heating element out of the main heating element and the sub-heating element is performed by a charging / discharging storage means, the storage means is switched. By using it together with the activation of the power supply, it is possible to provide an image forming apparatus that can stop the switching power supply of the image forming apparatus at the time of standby without increasing the cost.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following, as an embodiment of the present invention, a laser beam printer using an on-demand fixing device that does not require adjustment of the fixing temperature during standby for image formation will be described as an example. However, the present invention is not limited to the laser beam printer, and can be applied to all image forming apparatuses using an electrophotographic process.

  In addition, the same parts as those described in the conventional technical example are omitted or simplified, and the same reference numerals used in the description of the conventional technical example are used.

  In the switching power supply circuit unit according to the present embodiment, an example will be described in which, based on a signal from an external device, the TRIAC connected in series to the AC line is made conductive by the electric power stored in the power storage means and the switching power supply is activated.

  FIG. 1 is a block diagram showing the configuration of the switching power supply circuit unit of the first embodiment, and FIG. 2 is a flowchart for explaining the transition / return to the standby state of the first embodiment.

  Here, the configuration of the switching power supply circuit unit of the first embodiment will be described with reference to FIG.

  The switching power supply 700 in this embodiment includes a rectifier circuit 704 and a DC-DC converter 705. By making the power switch 701 conductive, the commercial power supply 621 supplies an AC voltage to the rectifier circuit 704. The rectifier circuit 704 rectifies the AC voltage of the commercial power supply into a DC voltage. Reference numeral 705 denotes a DC-DC converter having a built-in switching element (not shown), which steps down and outputs the DC voltage rectified by the rectifier circuit to a DC voltage V used in the image forming apparatus.

  Reference numeral 555 denotes charging means for charging the power storage means 556, which performs constant current or constant voltage charging based on the DC voltage V. The image forming control unit 316 operates the charging unit 555 and conducts the opening / closing unit 706 made of a semiconductor or the like, so that the power storage unit 556 is charged. After charging, the operation of the power storage means 555 is stopped as necessary, and the first opening / closing means 706 is turned off.

  The power storage means 556 is composed of, for example, a plurality of electric double layer capacitor elements. An electric double layer capacitor is an element that has attracted attention in many fields in recent years because of its large capacitance of several F or more, better charging efficiency than a secondary battery, and a long life.

  The first opening / closing means 706 selects whether or not the power storage means 556 is charged by the charging means 555 in accordance with an instruction from the image forming control circuit 316. Since the opening / closing means 706 is open in FIG. A state where 556 is not charged is shown.

  A restart circuit for restarting the power supply 700 includes second opening / closing means 707, constant voltage means 708, phototriac coupler 702, and triac 703. The second opening / closing means 707 composed of a semiconductor or the like supplies the power stored in the power storage means 556 to the light emitting unit of the phototriac coupler 702 via the diode 709 in response to an image forming job signal from an external device. This is to select whether or not to do.

  Reference numeral 712 denotes an external device such as a personal computer, which is connected to an external device interface unit 711 for image formation via a USB or LAN network. When a job signal from an external device is transmitted to the external device interface unit 711 of the image forming apparatus, the job signal (or part of the job signal group) turns on the second opening / closing means 707.

  Here, in order to turn on the second opening / closing means 707 by a job signal from an external device, the following three patterns are conceivable depending on an interface signal with the external device. In any configuration, it is possible to realize the present embodiment, but in order to simplify the description, the following description of the embodiment will be made on the assumption of the configuration (1) below.

(1) Hardware signal A hardware signal is assigned to one of the signal lines on the interface with the external device 712, and the hardware signal together with the image forming job signal is passed through the external device interface unit 711. The second opening / closing means 707 is directly turned on.

(2) Power Supply When power can be supplied from the external device 712 to the image forming apparatus in the interface with the external device 712, the second opening / closing means 707 is connected to the image forming apparatus via the external device interface unit 711 together with the image forming job signal. The power supply to is started, and the second opening / closing means 707 is directly turned on.

(3) Command signal When an image forming job signal is transmitted as a command signal from the external device 712 to the image forming apparatus, the external device interface unit 711 turns on the second opening / closing means 707 according to the command signal. It is necessary to convert the signal to Therefore, even when the switching power supply 700 is stopped during standby, only the external device interface unit 711 needs to be operated.

  When power can be supplied from the external device 712 to the image forming apparatus as described in (2), the external device interface unit 711 can be operated by both the output of the switching power supply 700 and the power supply power from the external device 712. Since the power is supplied from the external device 712 even when the switching power supply 700 is stopped, the external device interface unit 711 can continue to operate.

  On the other hand, when it is impossible to supply power from the external device 712 to the image forming apparatus, it is necessary to provide the auxiliary power supply unit 714 to keep the external device interface unit 711 operating. This auxiliary power supply means 714 is composed of a power generation means such as a solar cell and a power storage means such as an electric double layer capacitor. Even when the switching power supply 700 is stopped during standby, the external device interface unit 711 can be continuously operated by the electric power generated by the solar battery and stored in the electric double layer capacitor.

  In the capacitor type power storage means, the output power decreases with the start of discharging of the stored power. Therefore, a boost converter circuit system or the like is provided between the second opening / closing means 707 and the light emitting part of the phototriac coupler 702 as necessary. A constant voltage means may be added to stabilize the voltage applied to the light emitting part of the phototriac coupler 702.

  When a voltage is applied to the light emitting portion of the phototriac coupler 702 by closing the second opening / closing means 707, the light receiving portion of the phototriac coupler 702 is turned on, and the triac 703 connected in series to the AC line is also turned on.

  Next, the transition / return to the standby state, that is, the method of turning off / on the power supply 700 will be described using the timing chart shown in FIG.

  At the beginning of shipment of the image forming apparatus, power is not stored in the power storage unit 556. For this reason, the power supply is started by turning on the AC line by starting the power supply 700 when the user presses the power switch 701. The power switch 701 is, for example, a push switch type, and selects a type in which the contact is made conductive only when it is pressed and becomes non-conductive when released.

  When the power supply 700 is activated (step 801), the image formation control unit 316 is also activated, the third opening / closing means 710 made of a semiconductor or the like is turned on (step 802), and the voltage V is supplied to the light emitting unit of the phototriac coupler 702. Then, the light receiving unit of the phototriac coupler 702 is turned on, and the triac 703 connected in series to the AC line is turned on. As a result, the commercial power supply voltage continues to be supplied to the power supply 700 even if the user's hand is removed from the power switch 701, so that the power supply 700 continues to operate.

  The image formation control unit 316 detects the charging voltage value of the power storage unit 556, operates the charging unit 555 at a predetermined timing such as during a preparatory operation before image formation, during image formation, before and after image formation, and The first opening / closing means 706 is turned on to charge the power storage means 556.

  If the image forming job signal does not come from the external device 712 after a predetermined time has elapsed after the power switch 701 is turned on or after the image forming (step 803) ends, the image forming control unit 316 displays the power storage unit 556. Is detected, and it is detected that the battery is charged to a predetermined value or more (step 806). Here, if the predetermined value is not reached, the power storage unit 556 is charged by the charging unit 555 as described above (step 807).

  After the image forming control unit 316 confirms that the charging voltage of the power storage unit 556 is equal to or higher than a predetermined value, the third opening / closing unit 710 is turned off (step 809). As a result, the power supply to the light emitting part of the phototriac coupler 702 is cut off, the light receiving part of the phototriac coupler 702 is turned off, and the triac 703 is turned off. Therefore, since the supply of the commercial power source 621 of the power source 700 is cut off, the power source 700 stops. That is, it is possible to realize a standby state in which the power supply 700 is stopped and the power consumption of the image forming apparatus is approximately zero W (step 810).

  In the standby state, when an image forming job signal is transmitted from an external device such as a personal computer via the network to the external device interface unit 711 of the image forming apparatus (step 811), the job signal (or one of the job signal group) is transmitted. Part) directly turns on the second opening / closing means 707 (step 812).

  When the second opening / closing means 707 is turned on, the electric power stored in the power storage means 556 is supplied to the light emitting portion of the phototriac coupler 702 via the diode 709. Therefore, the power supply 700 is restarted when the triac 703 is turned on (step 813).

  Thereafter, the image formation control unit 316 turns on the third opening / closing means 710 (step 802), continues to supply the voltage V to the light emitting unit of the phototriac coupler 702, and maintains the power-on state. After the power source is restarted by the electric power of the power storage unit 556, when the voltage of the power storage unit 556 becomes lower than the voltage V than the forward voltage Vf of the diode 709, the discharge from the power storage unit 556 is blocked by the diode 709.

  The image formation control unit 316 performs image formation after performing predetermined image formation preparation such as warm-up of the fixing unit 23. After that, if an image forming job signal does not come from the external device 712 even after a predetermined time has elapsed, a standby state in which the power consumption of the image forming apparatus is approximately zero W can be realized by repeating the above operation.

  Here, the energy capacity of the power storage means is determined based on the fact that there is still enough charge to start the power supply even if the charge drops due to natural discharge after being left for about 8 hours, which is the normal business hours of the office. Is good. In this case, if the image forming job is not transmitted for about 8 hours, the power supply 700 is turned off, so that the energy stored in the power storage unit 556 is discharged and the power supply 700 cannot be restarted. At this time, it is necessary to restore the power by directly operating the power switch 701 by the user. For example, the power switch 701 may be operated only once at the start time of the company. If the energy capacity of the power storage means is increased more than necessary, the power storage means increases in size and costs, so it is necessary to select a capacity suitable for normal use.

  With the configuration as described above, power is turned off during standby, and even when there is no power supply capability, power is turned on by an image forming job signal from an external device, so that power consumption in the standby state of the image forming apparatus is achieved. Can be about zero W.

  In the switching power supply circuit unit in the present embodiment, an example will be described in which a relay connected in series to the AC line is made conductive by power stored in the power storage unit based on a signal from an external device, and the switching power supply is activated.

  FIG. 3 is a block diagram showing the configuration of the switching power supply circuit section of the second embodiment.

  Here, the configuration of the switching power supply circuit section of the second embodiment will be described with reference to FIG.

  The same parts as those described in the first embodiment are omitted or simplified, and are denoted by the same reference numerals used in the description of the first embodiment.

  The switching power supply 700 in this embodiment includes a rectifier circuit 704 and a DC-DC converter 705. By making the power switch 701 conductive, the commercial power supply 621 supplies an AC voltage to the rectifier circuit 704. The rectifier circuit 704 rectifies the AC voltage of the commercial power supply into a DC voltage. Reference numeral 705 denotes a DC-DC converter having a built-in switching element (not shown), which steps down and outputs the DC voltage rectified by the rectifier circuit to a DC voltage V used in the image forming apparatus.

  Reference numeral 555 denotes charging means for charging the power storage means 556, which performs constant current or constant voltage charging based on the DC voltage V. The image forming control unit 316 operates the charging unit 555 and causes the opening / closing unit 706 to conduct so that the power storage unit 556 is charged. After charging, the operation of the power storage means 555 is stopped as necessary, and the first opening / closing means 706 is turned off.

  The first opening / closing means 706 selects whether or not the power storage means 556 is charged by the charging means 555 in accordance with an instruction from the image formation control circuit 316. In FIG. 3, since the opening / closing means 706 is open, the power storage means A state where 556 is not charged is shown.

  A restart circuit for restarting the power supply 700 includes a second opening / closing means 707, a constant voltage means 708, and a relay 722. The second opening / closing means 707 made of a semiconductor or the like supplies power stored in the power storage means 556 to the coil portion of the relay 722 via the diode 709 in response to an image forming job signal from an external device. It is to select whether or not.

  Reference numeral 712 denotes an external device such as a personal computer, which is connected to an external device interface unit 711 for image formation via a USB or LAN network. When a job signal from an external device is transmitted to the external device interface unit 711 of the image forming apparatus, the job signal (or part of the job signal group) turns on the second opening / closing means 707.

  In the capacitor type power storage means, the output power decreases with the start of discharging of the stored power. Therefore, a constant voltage such as a boost converter circuit system is provided between the second opening / closing means 707 and the coil portion of the relay 722 as necessary. Means may be added to stabilize the voltage applied to the coil portion of the relay 722.

  When a voltage is applied to the coil portion of the relay 722 by closing the second opening / closing means 707, the contact portion of the relay 722 is turned on, whereby the AC line is conducted.

  Hereinafter, the phototriac coupler and triac described in the first embodiment are replaced with relays as described above, so that the transition to the standby state / return, that is, the power supply 700 is turned off, based on the flow shown in FIG. / ON becomes possible.

  As described above, as in the first embodiment, when the power is turned off during standby and the power supply capability is not available, the power is turned on by an image forming job signal from an external device, so that the standby state of the image forming apparatus is reached. The power consumption can be about zero W.

  In addition, by mechanically turning off the AC line using a relay, the switching power supply is less susceptible to sudden external surge noise from the commercial power supply during standby (relay off), and the reliability of the power supply circuit is further improved. .

  In the present embodiment, an example will be described in which the energy of the power storage means is used for the heater of the fixing device, and the triac connected in series to the AC line is made conductive by the electric power stored in the power storage means to start the switching power supply. .

  FIG. 4 is a block diagram of the drive and control circuit for the halogen heater of the third embodiment, and FIG. 5 is a block diagram showing the configuration of the switching power supply circuit section of the third embodiment.

  Here, the driving and control circuit of the halogen heater in the third embodiment will be described with reference to FIG.

  The same parts as those described in the first embodiment are omitted or simplified, and are denoted by the same reference numerals used in the description of the first embodiment.

  Reference numeral 621 denotes an AC power supply for connecting the image forming apparatus. The image forming apparatus supplies the commercial power supply to the halogen heater 601 through an AC filter (not shown) to cause the halogen heater 601 to generate heat.

  The power supply to the halogen heater 601 is controlled by the triac 650 to be energized or interrupted. The resistors 651 and 652 are bias resistors for the triac 650, and the phototriac coupler 653 is a device for isolating the primary and secondary. The triac 650 is turned on by energizing the light emitting diode of the phototriac coupler 653. A resistor 654 is a resistor for limiting the current of the phototriac, and is turned on / off by the transistor 655. The transistor 655 operates in accordance with an ON signal from the image formation control unit 316 via the resistor 656.

  Reference numeral 605 denotes a temperature detecting element for detecting the surface temperature of a pressure roller (not shown) in which the halogen heater 601 is disposed, for example, a thermistor temperature sensing element, and heat is applied on the surface of the pressure roller. It is arranged via an insulator having a dielectric strength voltage with a small time constant. The temperature detected by the temperature detection element 605 is detected as a partial pressure of the resistor 657 and the temperature detection element 605, and A / D is input to the image formation control unit 316 as a TH signal. The temperature on the surface of the pressure roller is monitored by the image formation control unit 316 as a TH signal and compared with the set temperature of the halogen heater 601 set inside the image formation control unit 316, The power to be supplied is calculated, and the image formation control unit 316 transmits an ON signal to the transistor 655 according to the control condition.

  In the case where power is supplied to the heating element and the control means fails and the heating element reaches thermal runaway, an excessive temperature rise prevention means 602 is disposed near the surface of the pressure roller as means for preventing excessive temperature rise. ing. The excessive temperature rise prevention means 602 is, for example, a thermal fuse or a thermo switch. When the heating element reaches a thermal runaway due to a failure of the triac 650 and the excessive temperature rise prevention means 602 reaches a predetermined temperature or more, the excessive temperature rise prevention means 602 is opened and the energization to the halogen heater 601 is cut off.

  Reference numeral 611 denotes a DC voltage-driven sub-heater (for example, 200 W) disposed in the fixing unit 23 and provided for shortening the warm-up time of the fixing unit. When the fixing device is warmed up, the image forming control unit 316 controls the fourth opening / closing means, thereby supplying the power stored in the power storage means 556 to the sub heater 611 via the fourth opening / closing means. The heater 611 is heated.

  During this warm-up, the halogen heater (main heater) 601 driven by the commercial power source is turned on, both the main and sub heaters are turned on, and the power from the commercial power source and the power from the power storage means are used together. The power that can be supplied (for example, 1500 W) or more can be supplied to the fixing device. Therefore, the warm-up time of the fixing device 23 can be shortened compared with the case where the sub heater 611 using the power storage unit 556 is not used.

  The energy capacity of the power storage means used here is used to supply power to the sub-heater 611 at the time of warm-up, so that, for example, a capacity capable of supplying 200 W of power for 15 seconds is used in the first and second embodiments. A power storage means having a larger capacity than the power storage means shown is required.

  In general, a capacitor such as an electric double layer capacitor has a small energy density and can charge and discharge a large current. On the other hand, the secondary battery has an energy density larger than that of the capacitor and is not suitable for charging / discharging a large current. Therefore, it is good also as a structure which combined the capacitor | condenser and the secondary battery in order to utilize both characteristics. That is, in the case of a load in which a large current flows instantaneously and then a low current continues, it is possible to supply energy from the capacitor with the large current and the secondary battery with the low current.

  Next, the configuration of the switching power supply circuit unit of the third embodiment will be described with reference to FIG.

  The switching power supply 700 in this embodiment includes a rectifier circuit 704 and a DC-DC converter 705. By making the power switch 701 conductive, the commercial power supply 621 supplies an AC voltage to the rectifier circuit 704. The rectifier circuit 704 rectifies the AC voltage of the commercial power supply into a DC voltage. Reference numeral 705 denotes a DC-DC converter having a built-in switching element (not shown), which steps down and outputs the DC voltage rectified by the rectifier circuit to a DC voltage V used in the image forming apparatus.

  Reference numeral 555 denotes charging means for charging the power storage means 556, which performs constant current or constant voltage charging based on the DC voltage V. The image forming control unit 316 operates the charging unit 555 and causes the opening / closing unit 706 to conduct so that the power storage unit 556 is charged. After charging, the operation of the power storage means 556 is stopped as necessary, and the first opening / closing means 706 is turned off.

  The first opening / closing means 706 selects whether or not the power storage means 556 is charged by the charging means 555 in accordance with an instruction from the image formation control circuit 316. Since the opening / closing means 706 is open in FIG. A state where 556 is not charged is shown.

  A restart circuit for restarting the power supply 700 includes second opening / closing means 707, constant voltage means 708, phototriac coupler 702, and triac 703. The second opening / closing means 707 composed of a semiconductor or the like supplies the power stored in the power storage means 556 to the light emitting unit of the phototriac coupler 702 via the diode 709 in response to an image forming job signal from an external device. This is to select whether or not to do.

  Reference numeral 712 denotes an external device such as a personal computer, which is connected to an external device interface unit 711 for image formation via a USB or LAN network. When a job signal from an external device is transmitted to the external device interface unit 711 of the image forming apparatus, the job signal (or part of the job signal group) turns on the second opening / closing means 707.

  Here, as described in the first embodiment, in order to turn on the second opening / closing means 707 by the job signal from the external device, the following three patterns can be considered by the interface signal with the external device. Although it is possible to realize the present embodiment in any configuration, an application example will be described below particularly in the case of using a command signal.

  When the image forming job signal is transmitted as a command signal from the external device 712 to the image forming apparatus, the external device interface unit 711 converts the image forming job signal into a signal for turning on the second opening / closing means 707 according to the command signal. There is a need. Therefore, even when the switching power supply 700 is stopped during standby, only the external device interface unit 711 needs to be operated.

  When it is impossible to supply power from the external device 712 to the image forming apparatus, the energy capacity of the power storage unit 556 described in this embodiment is for turning on the sub heater. The external device interface unit 711 may be continuously operated by the energy stored in the power storage unit 556, which is much larger than in the second embodiment.

  As in the first and second embodiments, it is necessary to provide the auxiliary power supply means 714 and keep the external device interface unit 711 operating. This auxiliary power supply means 714 is composed of a power generation means such as a solar cell and a power storage means such as an electric double layer capacitor. Even when the switching power supply 700 is stopped during standby, the external device interface unit 711 can be continuously operated by the electric power generated by the solar battery and stored in the electric double layer capacitor.

  In the capacitor type power storage means, the output power decreases with the start of discharging of the stored power. Therefore, a boost converter circuit system or the like is provided between the second opening / closing means 707 and the light emitting part of the phototriac coupler 702 as necessary. A constant voltage means 708 may be added to stabilize the voltage applied to the light emitting part of the phototriac coupler 702.

  In addition, since the voltage supplied to the sub-heater 611 is larger than the voltage supplied to the light emitting unit of the phototriac coupler 702, a separate constant voltage means (for example, a boosting method, not shown) is provided as necessary. It may be provided between the opening / closing means and the auxiliary heater 611. Alternatively, the charging voltage of the power storage means may be increased and the constant voltage means 708 may be a step-down circuit system.

  When a voltage is applied to the light emitting portion of the phototriac coupler 702 by closing the second opening / closing means 707, the light receiving portion of the phototriac coupler 702 is turned on, and the triac 703 connected in series to the AC line is also turned on.

  The power switch unit 715 may be arranged at either point A or B in FIG.

  Hereinafter, similarly to the first embodiment, based on the flow shown in FIG. 2, it is possible to shift / return to the standby state, that is, to turn off / on the power supply 700.

  As described above, as in the first embodiment, when the power is turned off during standby and the power supply capability is not available, the power is turned on by an image forming job signal from an external device, so that the standby state of the image forming apparatus is reached. The power consumption can be about zero W.

  In addition, in the case of an image forming apparatus that uses power storage means to supply power to the sub-heater during warm-up, the power for starting the switching power supply is supplied from the same power storage means, so that the standby cost is not increased. The power consumption in the state can be reduced to about zero W at a low cost.

  In the switching power supply circuit unit according to the present embodiment, the second charging unit is provided, and the power storage unit is continuously charged even during standby, and the triac connected in series to the AC line is made conductive by the electric power stored in the power storage unit. An example of starting the switching power supply will be described.

  FIG. 6 is a block diagram showing the configuration of the switching power supply circuit section of the fourth embodiment.

  Here, the configuration of the switching power supply circuit unit of the fourth embodiment will be described with reference to FIG.

  The same parts as those described in the first embodiment are omitted or simplified, and are denoted by the same reference numerals used in the description of the first embodiment.

  The switching power supply 700 in this embodiment includes a rectifier circuit 704 and a DC-DC converter 705. By making the power switch 701 conductive, the commercial power supply 621 supplies an AC voltage to the rectifier circuit 704. The rectifier circuit 704 rectifies the AC voltage of the commercial power supply into a DC voltage. Reference numeral 705 denotes a DC-DC converter having a built-in switching element (not shown), which steps down and outputs the DC voltage rectified by the rectifier circuit to a DC voltage V used in the image forming apparatus.

  Reference numeral 555 denotes a first charging means for charging the power storage means 556, which performs constant current or constant voltage charging based on the DC voltage V. The image forming control unit 316 operates the first charging unit 555 and causes the opening / closing unit 706 to conduct, thereby charging the power storage unit 556. After charging, the operation of the power storage means 556 is stopped as necessary, and the first opening / closing means 706 is turned off.

  The first opening / closing means 706 selects whether or not the power storage means 556 is charged by the first charging means 555 in accordance with an instruction from the image formation control circuit 316. In FIG. 6, the opening / closing means 706 is open. The state in which the power storage means 556 is not charged is shown.

  A restart circuit for restarting the power supply 700 includes second opening / closing means 707, constant voltage means 708, phototriac coupler 702, and triac 703. The second opening / closing means 707 composed of a semiconductor or the like supplies the power stored in the power storage means 556 to the light emitting unit of the phototriac coupler 702 via the diode 709 in response to an image forming job signal from an external device. This is to select whether or not to do.

  Reference numeral 712 denotes an external device such as a personal computer, which is connected to an external device interface unit 711 for image formation via a USB or LAN network. When a job signal from an external device is transmitted to the external device interface unit 711 of the image forming apparatus, the job signal (or part of the job signal group) turns on the second opening / closing means 707.

  In the capacitor type power storage means, the output power decreases with the start of discharging of the stored power. Therefore, a boost converter circuit system or the like is provided between the second opening / closing means 707 and the light emitting part of the phototriac coupler 702 as necessary. A constant voltage means may be added to stabilize the voltage applied to the light emitting part of the phototriac coupler 702.

  When a voltage is applied to the light emitting portion of the phototriac coupler 702 by closing the second opening / closing means 707, the light receiving portion of the phototriac coupler 702 is turned on, and the triac 703 connected in series to the AC line is also turned on.

  Hereinafter, similarly to the first embodiment, based on the flow shown in FIG. 2, it is possible to shift / return to the standby state, that is, to turn off / on the power supply 700.

  Reference numeral 713 denotes a second charging means using a power generation element such as a solar cell or a heat-electric conversion element. Since an image forming apparatus is often used in a bright place such as an office, power generation by a solar cell is possible. In addition, since the vicinity of the fixing device is at a high temperature, it is possible to generate power using a thermo-electric conversion element or the like.

  When the charging voltage of the power storage unit becomes a predetermined value or less, the charging unit charges the power storage unit 556 by the electromotive force from the power generation element without depending on the instruction from the image formation control unit 316. Therefore, when the voltage of the power storage unit 556 is reduced due to natural discharge during standby when the power source 700 is stopped, the power can be supplemented by the second charging unit.

  Assuming that the energy capacity of the power storage means is that the power capacity of the power storage means remains for about 8 hours, which is the normal business hours of the office, and even if the charge drops due to natural discharge, there is still enough charge to start the power supply. Suppose that it was decided as a standard. In this embodiment, the charging power from the second charging means can compensate for part or all of the power lost due to the natural discharge, so that the time for which the charge enough to start the power source remains is extended to 8 hours or more. be able to. That is, the energy capacity of the power storage means can be reduced, and the power storage means can be reduced in size and cost.

  As described above, as in the first embodiment, when the power is turned off during standby and the power supply capability is not available, the power is turned on by an image forming job signal from an external device, so that the standby state of the image forming apparatus is reached. The power consumption can be about zero W.

  Further, the second charging means using the power generation means is provided, and the natural discharge from the power storage means can be mitigated by the electromotive force from the second charging means. For this reason, the energy capacity of the power storage means can be reduced, and the power storage means can be reduced in size and cost.

  In each of the above-described embodiments, an example in which a plurality of electric double layer capacitors is used as an example of a capacitor is shown. In consideration of limited use conditions and sequence, replace with other capacitors such as multiple aluminum electrolytic capacitors with large capacity, and secondary batteries such as nickel metal hydride batteries, lithium batteries, and proton polymer batteries (required) Needless to say, it can be used as a power storage means. However, since the secondary battery excluding the proton polymer battery generally has a short charge / discharge count of 500 to 1000 times, it is preferably used as a detachable replacement part when the secondary battery life is less than the device life. Will.

  Moreover, although it is preferable to use a semiconductor switch such as an FET for reasons of on / off durability, the first to fourth opening / closing means may use a mechanical switch such as a relay if there is no problem in the life such as the number of on / off times. I do not care.

  Further, in each of the above-described embodiments, the use of a push switch type switch as the power switch 701 has been described. However, a switch of a type called a seesaw type or a toggle type and a switch with an electromagnetic reset function (not shown) that can be turned off by using a signal from the image formation control unit 316 by using an electromagnetic reset function is used. It doesn't matter. When such a type of switch is used, when the switch is turned on, the contact is latched to the on side by the user, so that the opening / closing means 710 is unnecessary. When it is necessary to turn off, the contact of the switch with the electromagnetic reset function can be latched to the off side by a signal from the image formation control unit 316.

Explanatory drawing which shows the structure of the switching power supply circuit part of the image forming apparatus concerning 1st Example of this invention. 6 is a flowchart for explaining the transition / return to the standby state of the image forming apparatus according to the first embodiment of the present invention. Explanatory drawing which shows the structure of the switching power supply circuit part of the image forming apparatus concerning 2nd Example of this invention. Explanatory drawing which shows the structure of the fixing device drive part of the image forming apparatus concerning 3rd Example of this invention. Explanatory drawing which shows the structure of the switching power supply circuit part of the image forming apparatus concerning 3rd Example of this invention. Explanatory drawing which shows the structure of the switching power supply circuit part of the image forming apparatus concerning the 4th Example of this invention. Conventional image forming apparatus apparatus schematic diagram Conventional scanner unit illustration Explanatory diagram showing the configuration of a conventional switching power supply circuit section The figure which shows the outline | summary of the relationship between time to reach the printing temperature of the conventional fixing device, and fixing power

Explanation of symbols

13 Laser beam 18 Photosensitive drum 11 Scanner unit 14 Developer 19 Transfer device 23 Fixing device 316 Image forming apparatus control circuit 555 Charging circuit 556 Power storage means 601 Main heater (halogen heater)
602 Thermal fuse 605 Thermistor 611 Sub heater 621 Commercial power supply 650 Triac 700 Switching power supply 701 Power switch 702 Phototriac coupler 703 Triac 704 Rectifier circuit 705 DC-DC converter 708 Constant voltage means 711 External equipment interface 712 External equipment 713 Second charging means 714 Auxiliary power supply means 715 Switch unit 722 Relay

Claims (17)

An interface for connecting to an external device;
A converter that converts commercial power supply voltage to DC voltage;
Control means for stopping the converter after elapse of a predetermined time in an image forming standby state;
Chargeable / dischargeable power storage means for storing electric power;
Restarting means for restarting the converter using the electric power stored in the power storage means,
When the converter is stopped, the electric power stored in the power storage means is supplied to the restarting means by a predetermined signal transmitted from the external device via the interface unit, and the converter is restarted. Image forming apparatus. An interface for connecting to an external device;
A converter that converts commercial power supply voltage to DC voltage;
Control means for stopping the converter after elapse of a predetermined time in an image forming standby state;
Chargeable / dischargeable power storage means for storing electric power;
First charging means for charging the power storage means with a commercial power source;
A second charging unit that includes the power generation unit and charges the power storage unit with electric power generated by the power generation unit;
Restarting means for restarting the converter using the electric power stored in the power storage means,
When the converter is stopped, the electric power stored in the power storage means is supplied to the restarting means by a predetermined signal transmitted from the external device via the interface unit, and the converter is restarted. Image forming apparatus.   The image forming apparatus according to claim 2, wherein the power generation unit is a solar cell or a thermal-electric conversion element.   The image forming apparatus further includes fixing means for fixing the toner image to the transfer material by applying heat of a heating element to the transfer material on which the toner image is formed, and the fixing means does not require preheating during standby The image forming apparatus according to claim 1, wherein the image forming apparatus is an on-demand fixing unit that heats the heat generating pair during printing. An interface for connecting to an external device;
A converter that converts commercial power supply voltage to DC voltage;
Control means for stopping the converter after elapse of a predetermined time in an image forming standby state;
Chargeable / dischargeable power storage means for storing electric power;
Restarting means for restarting the converter using the electric power stored in the power storage means;
A transfer material on which a toner image is formed, including a first heating element that generates heat using electric power supplied from a commercial power source and a second heating element that generates heat using electric power stored in a power storage unit Fixing means for fixing the toner image to the transfer material by applying heat of the heating element to
When the converter is stopped, the electric power stored in the power storage means is supplied to the restarting means by a predetermined signal transmitted from the external device via the interface unit, and the converter is restarted. Image forming apparatus.   The image forming apparatus according to claim 5, wherein the power storage unit supplies power to the interface unit when the converter is stopped.   6. The image forming apparatus according to claim 5, wherein the fixing unit is an on-demand fixing unit that does not require preheating during standby and heats a heat generating pair during printing.   7. The image forming apparatus according to claim 4, wherein the on-demand fixing unit is a fixing unit using a ceramic surface heating heater, an electromagnetic induction heating fixing method, or a halogen heater.   9. The image forming apparatus according to claim 1, wherein the image forming apparatus further includes auxiliary power supply means, and power is supplied from the auxiliary power supply means to the interface unit when the converter is stopped. .   The image forming apparatus according to claim 9, wherein the auxiliary power supply unit includes a dedicated auxiliary power generation unit and an auxiliary power storage unit.   The image forming apparatus according to claim 1, wherein the control unit detects a charging voltage of the power storage unit and charges the power storage unit at a predetermined timing.   The control unit stops the converter after detecting that a predetermined time has passed in an image forming standby state and that the charging voltage of the power storage unit is equal to or higher than a predetermined value. The image forming apparatus according to any one of 11.   The image forming apparatus further includes first switch means connected in series to a commercial power line for supplying commercial power to the converter, and the restarting means is connected in parallel with the first switch means. The image forming apparatus according to claim 1, further comprising a second switch unit.   14. The image forming apparatus according to claim 13, wherein the first switch means is a push switch or a seesaw switch that can be operated by a user, and the second switch means is a triac or a relay.   The image forming apparatus according to claim 1, wherein the power storage unit includes at least one of a capacitor, a secondary battery, or a power storage unit that is a combination of a capacitor and a secondary battery.   The image forming apparatus according to claim 1, wherein the power storage unit includes at least one of an electric double layer capacitor, a proton polymer battery, and a nickel metal hydride battery.   The image forming apparatus according to any one of claims 1 to 16, wherein the energy capacity of the power storage means is a capacity capable of starting the converter even if the converter is kept off for at least 8 hours. apparatus.

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