JP4405166B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus such as a copying machine, a digital multifunction peripheral, or a printer that heats a fixing member of a fixing device using an auxiliary power source.
[0002]
[Prior art]
An image forming apparatus such as a copying machine or a printer forms an image on a recording medium such as plain paper or OHP. For this image formation, an electrophotographic system is adopted because of high-speed image formation, image quality, cost, and the like. The electrophotographic method is a method in which a toner image is formed on a recording medium, and the formed toner image is fixed on the recording medium with heat and pressure. The heat roll method is the most current fixing method from the viewpoint of safety and the like. Many have been adopted. In the heat roll method, a heat roller heated by a heating member such as a halogen heater and a pressure roller disposed opposite to the heat roller are pressed to form a mutual pressure contact portion called a nip portion, and a toner image is formed at the nip portion. In this method, heating is performed through the recording medium on which is transferred.
[0003]
In order to protect the environment in recent years, standards and regulations have become stricter every year in countries around the world due to demands for energy saving. For this reason, energy-saving efforts such as the improvement of products from the problems of limiting the limited commercial power supply (for example, 100V 15A in Japan) and shortening the rise time (warm-up time) of products have been activated. ing. Copiers and printer products are also a major issue for speeding up and colorization in recent years.
[0004]
In considering energy saving of this image forming apparatus, power consumption of a fixing device that fixes toner on a recording medium cannot be ignored. For example, Patent Document 1 proposes a technique for realizing energy saving by increasing the maximum power supply by using an auxiliary power source for the fixing device. The fixing device disclosed in Patent Document 1 supplies power from a main power supply device and a secondary battery or a primary battery at startup, and uses a CADNICA battery or a lead battery as a secondary power source. Yes. Such secondary batteries have the property that the capacity deteriorates and decreases when charging and discharging are repeated many times, and the life is shortened as discharging is performed with a large current. In general, even for CADNICA batteries that are considered to have a long life with a large current, the number of charge / discharge cycles is about 500 to 1000 times, and if the charge / discharge is repeated 20 times a day, the battery life will be reached in about one month. If you end up. For this reason, there is a disadvantage in that it takes time and labor for replacement, and the running cost such as the battery cost for replacement is very high. Furthermore, lead acid batteries are not preferred for office equipment, such as using liquid sulfuric acid.
[0005]
For this reason, for example, Patent Document 2 discloses an image forming apparatus using a large-capacity capacitor such as an electric double layer capacitor as an auxiliary power source of the fixing device. Such an electric double layer capacitor has the property that the number of repetitions of charging and discharging is tens of thousands to hundreds of thousands or more, and the life due to the number of charging and discharging is much longer than that of the battery.
[0006]
However, when used in a fixing device of an image forming apparatus of a copying machine or a printer product, it cannot be said that the number of repetitions of charging and discharging is sufficient for supplying power to a heat generating member for heat fixing. In particular, for high-speed machines and color machines that require high-capacity supply power, in order to maintain the fixing performance of the image forming apparatus, replacement due to the life of a large-capacity capacitor or replacement in case of failure is indispensable.
[0007]
In addition, the electric double layer capacitor is difficult to discharge the charged electric charge in a short time (about 10% down in 10 hours in natural discharge), and requires safety precautions when replacing.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-282821
[Patent Document 2]
JP 2002-184554 A
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above, and an object of the present invention is to provide an image forming apparatus having improved safety when a large-capacity capacitor is used as an auxiliary power source of a fixing device.
[0010]
[Means for Solving the Problems]
  In order to solve the above-described problem, the invention according to claim 1 is to charge a capacitor in an image forming apparatus that increases a maximum supply power to a fixing device using a capacitor that can be charged by power from a commercial power source. Charging means;in frontA connecting member that relays power input from the commercial power source to the charging means;The capacitor;A connection unit for connecting a power supply line from the charging means to the capacitor, a capacitor unit that is detachable from the device, and a capacitor charge / discharge circuit that is connected to the capacitor and charges and discharges the capacitor. A controller that controls discharge of the capacitor by the capacitor charge / discharge circuit and supplies electric power to the fixing device on condition that the capacitor unit is mounted on the device.The connecting member relays power from the commercial power source to the charging means when the capacitor unit is mounted on the device.It is characterized by that.
[0011]
  According to the above invention,A connecting member that relays power input from a commercial power source to the charging unit performs relaying of power from the commercial power source to the charging unit when the capacitor unit is attached to the device.When the capacitor unit is removed from the device, the power input from the commercial power source to the charging means is also cut off at the same time.As a result, the power supply to the capacitor charge / discharge circuit is reliably cut off, so the auxiliary power supply can be easily replaced in a short time, and service personnel can directly connect to the auxiliary power supply or the electrode part of the charger. Since it is not touched, an electric shock can be prevented and safety can be improved.
[0018]
  Claims2The invention according to claim1In the invention according to the above,CapacitorsElectric double layer capacitorIs,It is characterized by that.
[0019]
  According to the above invention,CapacitorsIs composed of an electric double layer capacitor.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of an image forming apparatus according to the invention will be described in detail with reference to the drawings.
[0021]
[Entire configuration of image forming apparatus]
FIG. 1 is a cross-sectional view showing a schematic mechanical configuration of an image forming apparatus to which the present invention is applied. An image forming apparatus 1 shown in FIG. 1 includes a digital multifunction peripheral, and has a copying function, a printer function, a facsimile function, and the like. It is possible to switch between the copy function, printer function, and facsimile function in order by using the application switching key of the operation unit (not shown), and the copy mode is selected when the copy function is selected, and when the printer function is selected. When the facsimile mode is selected, the facsimile mode is selected.
[0022]
As shown in FIG. 1, the image forming apparatus 1 includes an automatic document feeder (hereinafter referred to as “ADF”) 10 that automatically conveys a document to a document reading position, and image information of the document conveyed to the document reading position. An image reading device 20 that optically reads, a writing unit 30 that writes image information of the read document on the printer unit 40, and a toner image of the image information of the document written by the writing unit 30 to form a transfer paper or the like And a printer unit 40 for transferring and discharging the material onto a transfer material.
[0023]
The operation of each mode of the image forming apparatus will be described with reference to FIG. First, the operation in the copy mode will be described. In the copy mode, in the ADF 10, a document bundle in which a document is placed on the document table 102 is placed on the document table 102, and when the start key on the operation unit is pressed, the bottom document is fed by the feed roller. 103 and a feeding belt 104 are fed to a predetermined position on the contact glass 105. The ADF 10 has a count function that counts up the number of documents every time a document is fed. The document on the contact glass 105 is discharged onto a sheet discharge tray 108 by a feeding belt 104 and a discharge roller 107 after image information is read by an image reading device 20 as an image input unit.
[0024]
When the document set detector 109 detects that the next document is on the document table 102, the lowermost document on the document table 102 is similarly fed by the paper feed roller 103 and the feed belt 104. It is fed to a predetermined position on the contact glass 105. After the image information is read by the image reading device 20, the original on the contact glass 105 is discharged onto the paper discharge tray 108 by the feeding belt 104 and the discharge roller 107. The paper feed roller 103, the feed belt 104, and the discharge roller 107 are driven by a transport motor (not shown).
[0025]
The first paper feeding device 110, the second paper feeding device 111, and the third paper feeding device 112 as the paper feeding means are stacked on the first tray 113, the second tray 114, and the third tray 115, respectively, when selected. A sheet made of transfer paper as a transfer material is fed, and this transfer paper is conveyed by the vertical conveyance unit 116 to a position where it abuts on the photoconductor 117 as an image carrier. For example, a photosensitive drum is used as the photosensitive member 117, and is rotated by a main motor (not shown).
[0026]
Image information of the original read by the image reading device 20 is converted into optical information by a writing unit 30 as writing means via an image processing means (not shown), and the photosensitive drum 117 is charged by a charger (not shown). After being uniformly charged, it is exposed with light information from the writing unit 30 to form an electrostatic latent image. The electrostatic latent image on the photosensitive drum 117 is developed by the developing device 119 to become a toner image.
[0027]
The conveyance belt 120 serves as both a sheet conveyance unit and a transfer unit, and a transfer bias is applied from a power source. The conveyance belt 120 is conveyed on the photosensitive drum 117 while conveying the transfer sheet conveyed from the vertical conveyance unit 116 at a constant speed with the photosensitive drum 117. The toner image is transferred onto the transfer paper. The transfer paper is fixed with a toner image by a fixing device 121 and is discharged to a paper discharge tray 123 by a paper discharge unit 122. The photosensitive drum 117 is cleaned by a cleaning device (not shown) after the toner image is transferred. The photosensitive drum 117, the charger (not shown), the writing unit 30, the developing device 119, and the transfer unit described above constitute an image forming unit that forms an image on transfer paper based on image information.
[0028]
The above operation is an operation for copying an image on one side of a sheet in a normal mode. However, when copying an image on both sides of a transfer sheet in a duplex mode, the sheet feeding trays 113 to 115 are used. The transfer paper that has been fed and on which the image is formed as described above is switched by the paper discharge unit 122 to the double-sided paper feed path 124 side instead of the paper discharge tray 123 side, and is switched back by the reversing unit 125. The front and back sides are reversed and conveyed to the duplex conveying unit 126.
[0029]
The transfer paper transported to the double-sided transport unit 126 is transported to the vertical transport unit 116 by the double-sided transport unit 126, transported to the position where it abuts on the photoconductive drum 117 by the vertical transport unit 116, and then onto the photoconductive drum 117. In addition, a toner image formed in the same manner as described above is transferred to the back surface, and the toner image is fixed by the fixing device 121, whereby double-sided copying is performed. This double-sided copy is discharged to the paper discharge tray 123 by the paper discharge unit 122.
[0030]
Further, when the transfer paper is reversed and discharged, the transfer paper that is switched back by the reversing unit 125 and turned upside down is not conveyed to the duplex conveying unit 126 but is discharged via the reverse discharge conveyance path 127. The paper is discharged to the paper discharge tray 123 by the unit 122.
[0031]
Next, the print mode and the facsimile mode will be described. In the print mode, image information from the outside is input to the writing unit 30 instead of the image information from the image processing means, and an image is formed on the transfer paper by the image forming means. Further, in the facsimile mode, the image information from the image reading means is transmitted to the other party by a facsimile transmission / reception unit (not shown), and the image information from the other party is received by the facsimile transmission / reception unit, instead of the image information from the image processing means. By inputting to the writing unit 30, an image is formed on the transfer paper by the above-described image forming means.
[0032]
[Configuration of Fixing Device]
FIG. 2 is a diagram showing an internal configuration of the fixing device 121 shown in FIG. A fixing device 121 shown in FIG. 2 is disposed inside a fixing roller 151 that is a fixing member, a pressure roller 152 that is a pressure member that presses the fixing roller 151, and the fixing roller 151. The AC fixing heater HT2 that is a main heating element and the fixing heater HT1 that is an auxiliary heating element, and a temperature detection unit that is in contact with the surface of the fixing roller 151 and detects the surface temperature (fixing temperature) of the fixing roller 151. A thermistor TH11.
[0033]
The fixing roller 151 is made of an elastic member such as silicon rubber, and thermally fixes the toner image transferred to the transfer paper. The pressure roller 152 is made of an elastic member such as silicon rubber, and is pressed against the fixing roller 151 with a constant pressure by a pressure unit (not shown). The fixing heater HT1 and the AC fixing heater HT2 are generally halogen heaters, but other resistors may be used. The AC fixing heater HT2 is supplied with AC power from an AC heater driving circuit (see FIG. 3) to generate heat (lights on), and the fixing heater HT1 is supplied with electric power from a capacitor (see FIG. 3) as an auxiliary power source to generate heat. (Light.
[0034]
In the fixing device having the above-described configuration, the fixing roller 151 and the pressure roller 152 are rotated by a drive mechanism (not shown), and the sheet P such as transfer paper carrying the toner Toner is formed between the fixing roller 151 and the pressure roller 152. When passing through the nip portion, the toner Toner is fixed to the sheet P by heating and pressing by the fixing roller 151 and the pressure roller 152.
[0035]
Here, the fixing member and the pressure member are generally rollers as shown in FIG. 2, but the fixing member and the pressure member are not limited to rollers, and an endless belt or the like is used for one or both of them. May be. Further, although the fixing heater HT1 and the AC fixing heater HT2 are arranged inside the fixing roller 151, they may be arranged at any position as long as the fixing roller 151 can be heated.
[0036]
[Power supply circuit of fixing device]
FIG. 3 is a diagram illustrating a configuration of a power supply circuit of the fixing device. The power supply circuit 200 of the fixing device shown in FIG. 3 includes a main power SW 201 that turns on and off the supply of the AC power ACPS1, a control unit 202 that controls each part of the power supply circuit 200, and capacitor charging for charging the capacitor CP. , A DC power generation circuit 204 that generates DC power for the image forming apparatus, an AC heater driving circuit 205 that supplies AC power to the AC fixing heater HT2, and an input that detects an input current input from the AC power supply ACPS1. A current detection circuit 206, an interlock switch 207, a capacitor charge / discharge circuit 208 that discharges the capacitor CP1 to supply DC power to the fixing heater HT1, a capacitor CP1 that is an auxiliary power source for the fixing heater HT1, and a capacitor CP1 Is switched between the capacitor charger 203 side and the discharger side 210. A conductive SW209, and a discharger 210 for discharging charges remaining in the capacitor CP1.
[0037]
AC power supply ACPS1 supplies AC power to AC heater drive circuit 205, DC power supply generation circuit 205, and capacitor charger 203 via main power supply SW201 and input current detection circuit 206.
[0038]
The control unit 202 controls each unit of the power supply circuit 200 and controls operations of the capacitor charger 203, the AC heater driving circuit 205, and the capacitor charging / discharging circuit 208. Specifically, the control unit 202 sends a control signal S1 to the capacitor charger 203 to control the charging operation of the capacitor CP1 by the capacitor charger 203. The control unit 202 also sends control signals S3 and S4 to the capacitor charge / discharge circuit 208 to control the ON / OFF operation of the fixing heater HT1 by the capacitor charge / discharge circuit 208. The control unit 202 also sends control signals S8 and S9 to the AC heater driving circuit 205 to control the ON / OFF operation of the fixing heater HT2 by the AC heater driving circuit 205.
[0039]
The input current detection circuit 206 is provided between the main power supply SW201, the AC heater driving circuit 205, the DC power supply generation circuit 204, and the capacitor charger 203. The input current detection circuit 206 is an input of the AC power supply ACPS1 that is input via the main power supply SW201. The current is detected, and the detected current S7 is output to the control unit 202. This input current varies according to the operating states of the AC heater drive circuit 205, the DC power supply generation circuit 204, the capacitor charger 203, and the image forming apparatus.
[0040]
The DC power generation circuit 204 is used for the power supply Vcc mainly used in the control system inside the image forming apparatus, mainly for the drive system, and the medium / high-voltage power supply based on the AC power supply ACPS1 input via the main power SW201. The generated power supply Vaa is generated and output to each unit.
[0041]
The interlock switch 207 is a switch that is turned ON / OFF in conjunction with a cover of the image forming apparatus (not shown), a drive member that can be touched by opening the covers of the image forming apparatus, and a medium / high voltage power supply member When the cover is opened, the power supply is shut off so that the operation of the drive member is stopped or the voltage application to the application member is stopped when the cover is opened. A part of the power supply Vaa generated by the DC power generation circuit 204 is input to the interlock switch 207, and is input to the capacitor charging / discharging circuit 208 and the AC heater driving circuit 205 via the interlock switch 207.
[0042]
The AC heater drive circuit 205 turns the fixing heater HT1 on and off in response to control signals S8 and S9 input from the control unit 202.
[0043]
Capacitor charger 203 is connected to capacitor CP1 and charges capacitor CP1 based on control signal S1 input from control unit 202.
[0044]
Capacitor CP1 is formed of a large capacity capacitor such as an electric double layer capacitor. The capacitor CP1 is connected to the capacitor charger 203 and the capacitor discharge circuit 208, and is charged by the capacitor charger 203. The charged electric power is fixed to the fixing heater HT1 by ON / OFF control of the capacitor charge / discharge circuit 208. To be supplied.
[0045]
Capacitor charge / discharge circuit 208 discharges the electric charge accumulated in capacitor CP1 in accordance with control signals S3 and S4 input from control unit 202, and turns on / off fixing heater HT1.
[0046]
The discharge SW 209 is a SW for switching the connection of the capacitor CP1 between the capacitor charger 203 and the capacitor charge / discharge circuit 208 side and the discharger 210 side. Capacitor charge / discharge circuit 208 and capacitor charger 203 have a fixed (hereinafter referred to as COM) contact connected to capacitor CP1 via a normally closed (hereinafter referred to as NC) contact of discharge SW209.
[0047]
A normally open (hereinafter, NO) contact of the discharge SW 209 is connected to a discharger 210 for discharging the charge charged in the capacitor CP1 which is an auxiliary power source.
[0048]
Normally, the discharge SW 209 is OFF and the capacitor charger 203 is N.P. Although connected to the capacitor CP1 via the C contact, when the discharge SW 209 is switched to ON, N.P. The COM contact is connected to the discharger 210 through the O contact, and the charge charged in the capacitor CP1 can be discharged to the discharger 210.
[0049]
The arrangement position of the discharge SW 209 cannot be easily touched by the user and is easily maintained by a service person, for example, the inside of the cover to be removed to handle the capacitor CP1, the side of the capacitor CP1, or the capacitor CP1. It is preferable to arrange in itself.
[0050]
The thermistor TH11 is provided in the vicinity of the fixing roller 151 and outputs a detection signal S6 corresponding to the surface temperature of the fixing roller 151 to the control unit 202. Since the resistance value of the thermistor TH11 changes depending on the temperature, the control unit 202 detects the surface temperature of the fixing roller 151 from the detection signal S6 using the temperature change of the resistance value.
[0051]
In the power supply circuit, the discharger 210 for discharging the charge charged in the capacitor CP1 and the discharge SW209 for switching the connection of the capacitor CP1 between the capacitor charger 203 side and the discharger 210 side are provided. The charge remaining in the capacitor CP1 that does not discharge in a short time can be discharged, and an electric shock can be prevented when replacing the capacitor CP1 to improve safety, and the safety of the image forming apparatus can be ensured. It becomes possible.
[0052]
[AC heater drive circuit]
FIG. 4 is a diagram showing a configuration of the AC heater driving circuit 205 of FIG. The AC heater drive circuit 205 includes a filter FIL21 that removes noise from the input AC power supply, a safety protection fixing relay RL21 that is turned ON / OFF according to a control signal S2 input from the control unit 202, and a fixing. The relay RL21 includes a diode D21 for preventing the back electromotive force and a heater ON / OFF circuit 220 that turns the fixing heater HT1 on and off based on a control signal S9 input from the control unit 202.
[0053]
The AC power supply ACPS1 is connected to one end side of the fixing heater HT2 via a filter FIL21 and a safety-protecting fixing relay RL21. The other end of the fixing heater HT2 is connected to the heater ON / OFF circuit 220.
[0054]
The heater ON / OFF circuit 220 turns on the triac TRI21 for turning on / off the AC power supply ACPS1 and the gate of the triac TRI21, and is a photocoupler for insulating the signal from the control unit 202 on the secondary side. PC21, a transistor TR21 for driving the light emitting side LED of the photocoupler PC21, a noise absorbing snubber circuit including a capacitor C21 and a resistor R21, a noise absorbing inductor L21, and a resistor R22 which is a continuity prevention resistor And resistors R23 and R24 which are current limiting resistors of the photocoupler PC21.
[0055]
In the AC heater driving circuit 205 configured as described above, the AC fixing heater HT2 is turned on when power is supplied in a state where both the safety-protecting fixing relay RL21 and the gate of the transistor TR21 are turned on.
[0056]
The control unit 202 turns on / off the control signal S8 supplied to the gate of the transistor TR21 of the heater ON / OFF circuit 220 in the state where the control signal S9 supplied to the fixing relay RL21 for safety protection is turned on, thereby AC fixing. The heater HT2 is turned on / off.
[0057]
[Configuration of Capacitor Charge / Discharge Circuit 208]
FIG. 5 is a diagram showing a configuration of the capacitor charge / discharge circuit 208 of FIG. As shown in FIG. 5, the capacitor charging / discharging circuit 208 detects the voltage across the charging / discharging switch 231, the fixing relay RL11 for safety protection, the diode D11 for preventing the back-up of the fixing relay RL11, and the capacitor CP1. And a both-end voltage detection circuit 232.
[0058]
As shown in FIG. 5, a charge / discharge switch 231 and a safety protection fixing relay RL11 are connected to both ends of the capacitor CP1. The charging / discharging switch 231 is turned on / off by a control signal S3 input from the control unit 202. Similarly, the fixing relay RL11 is turned ON / OFF by a fixing relay ON / OFF signal S4 input from the control unit 202.
[0059]
When both the charging / discharging switch 231 and the safety protection fixing relay RL11 are turned on, the electric charge accumulated in the capacitor CP1 is discharged to the fixing heater HT1, and electric power is supplied.
[0060]
The both-end voltage detection circuit 232 detects the both-end voltage of the capacitor CP1 and outputs the voltage signal S5 to the control unit 202. The control unit 202 constantly monitors the voltage signal S5 to monitor the charge state of the capacitor CP1.
[0061]
[Configuration of discharger]
FIG. 6 is a diagram illustrating a configuration example of the discharger 210 of FIG. As shown in FIG. 6, the discharger 210 is configured by connecting resistors R1 to Rn for discharging the capacitor CP1 in parallel, and one ends of the resistors R1 to Rn are grounded. Further, both ends of the resistors R1 to Rn are connected to N.V. Connected to the O contact. The resistors may be arranged alone or on the array.
[0062]
FIG. 7 shows another configuration example of the discharger 210. As shown in FIG. 7, in the discharger 210, discharge lamps (incandescent lamps, LEDs, neon tubes, etc.) LMP1 to LMPn for discharging the capacitor CP1 and resistors RL1 to RLn are connected in parallel, and the resistor RL1 The RLn side is grounded. Both ends of the discharger 210 are connected to the N.P. Connected to the O contact. The discharge lamps LMP <b> 1 to LMPn also serve as a guide for determining whether charges remain in the capacitor CP <b> 1 and also serve as a warning display for service personnel.
[0063]
Note that the discharger 210 may be configured by only the discharge lamps LMP1 to LMPn, but the discharge time can be shortened by inserting the resistors RL1 to RLn. Further, the discharge lamp and the resistor may be arranged alone or in an array.
[0064]
[Configuration of control unit]
FIG. 8 is a diagram showing a schematic configuration of the control unit 202 of FIG. The control unit 202 includes a CPU 241 and a memory 242.
[0065]
The CPU 241 is connected to a memory 242 for storing a program and data for controlling the image forming apparatus and the power supply circuit, and controls the image forming apparatus and the power supply circuit 200 based on the program stored in the memory 242. I do.
[0066]
The CPU 241 includes a voltage signal (analog signal) S5 representing the voltage across the capacitor CP1 detected by the voltage detection circuit 232 across the capacitor charging / discharging circuit 208, a thermistor TH11 and a resistor R41 for detecting the surface temperature of the fixing roller 151. The detection signal (analog signal) S6 divided by the resistance value, the detection current (analog signal) S7 in which the input current detection circuit 206 detects the input current of the image forming apparatus are input.
[0067]
Further, the CPU 241 turns on / off the control signal S1 for turning on / off the charging of the capacitor CP1, the control signal S3 for turning on / off the charging / discharging switch 231, and the fixing relay RL11 for safety protection via the IO port. A control signal S4, a control signal S8 for turning on / off the heater ON / OFF circuit 220, a control signal S9 for turning on / off the fixing relay R21 for safety protection, and the like are output.
[0068]
[Fixing roller temperature control]
FIG. 9 shows a timing chart for explaining the temperature control of the fixing roller 151. 6A shows the surface temperature T of the fixing roller 151, FIG. 4B shows the detected current (input current) I detected by the input current detection circuit 206, and FIG. 4C shows the AC fixing heater HT2. ON / OFF, (D) in the figure shows the discharge timing of the capacitor CP1.
[0069]
In the figure, a period t1 is a start-up period of the image forming apparatus (fixing roller 151), a period t2 is a waiting period of the image forming apparatus, a period t3 is a copying operation period, a period t4 is a waiting period of the image forming apparatus, a period t5 indicates the period of the low power mode, and the period t6 indicates the period of the energy saving mode.
[0070]
In FIG. 9, a period t1 is a period in which the surface temperature of the fixing roller 151 is raised to a predetermined temperature Tt. Normally, power is supplied from an AC power source to the AC fixing heater HT2 which is a heat generating member, and the fixing roller 151 is overheated as shown in FIG. In this period t1, the AC fixing heater HT2 is lit at full duty, but the copying operation is not performed. Therefore, as shown in FIG. 5B, the input current I becomes equal to or less than the maximum input current Imax. Yes.
[0071]
When the surface temperature of the fixing roller 151 detected by the thermistor TH11 reaches a target temperature Tt that is a temperature at which a copying operation can be performed, the power supply to the AC fixing heater HT2 is stopped, the start-up period t1 ends, and the copy standby Transition to the state (period t2).
[0072]
During the period t2, the control unit 202 repeatedly turns on when the temperature falls below the target temperature Tt while monitoring the surface temperature of the fixing roller 151, and turns off when reaching the target temperature Tt. In the period t2, even if the surface temperature of the fixing roller 151 reaches the target temperature Tt, if the copy start is started in a state where the periphery of the fixing device 121 is not sufficiently warmed, immediately after the start of copying, the AC is started as in the period t3. Even when the fixing heater HT2 is lit, the surface temperature of the fixing roller 151 may decrease. Actually, the copying operation can be performed even when the surface temperature of the fixing roller 151 becomes equal to or lower than the target temperature Tt. However, when the surface temperature of the fixing roller 151 becomes equal to or lower than Tmin, the fixing property cannot be secured, and the copying operation is stopped. I have to let it.
[0073]
During the copy operation during the period t3, the input current I of the DC power supply generation circuit 204 increases as the load current on the DC power supply side increases, and the input current of the entire apparatus also increases as shown in FIG. As a result, the power consumption of the entire device increases, and there is a possibility that the maximum input current Imax determined as the device may be reached. This maximum input current Imax cannot be exceeded due to device specifications. For this reason, in the period t3, as shown in FIG. 3C, the lighting rate of the AC fixing heater HT2 cannot be further increased, so that the surface temperature of the fixing roller 151 does not become Tmin or less as in the period t4. In addition, the surface temperature of the fixing roller 151 is raised by discharging the power previously charged in the capacitor (CP1) to the fixing heater HT1 provided separately from the AC fixing heater HT2.
[0074]
The period t4 is a standby period after the end of the copy operation. As in the period t2, the capacitor CP1 is discharged to supply power to the fixing heater HT1 as shown in FIG. ), When the surface temperature of the fixing roller 151 reaches the target temperature Tt, the discharge of the capacitor CP1 is stopped.
[0075]
In the period t5, even if the discharge supply from the capacitor CP1 is stopped, if the surface temperature of the fixing roller 151 can be maintained at the target temperature Tt only by the AC fixing heater HT2 as in the period t6, the AC fixing heater HT2 The temperature of the fixing roller 151 is controlled by ON / OFF control.
[0076]
FIG. 10 is a flowchart for explaining ON / OFF control of the fixing heater TH1 and the AC fixing heater TH2 of the control unit 202. With reference to FIG. 9, the ON / OFF control of the fixing heater TH1 and the AC fixing heater TH2 of the control unit 202 will be described.
[0077]
The control unit 202 detects the surface temperature of the fixing roller 151 based on the detection signal S6 input from the temperature detection thermistor TH11, and determines whether or not the surface temperature of the fixing roller 151 is equal to or higher than the target temperature Tt (step S1). ). As a result of this determination, when the surface temperature of the fixing roller 151 is equal to or higher than the target temperature Tt (“Y” in step S1), the control unit 202 turns off the control signals S3 and S4 output to the capacitor charge / discharge circuit 208. Then, the fixing heater HT1 is turned off (step S2), and the control signals S8 and S9 output to the AC heater driving circuit 205 are turned off to turn off the AC fixing heater HT2 (step S3).
[0078]
On the other hand, when the surface temperature of the fixing roller 151 is not equal to or higher than the target temperature Tt (“N” in step S1), the control unit 202 first determines whether or not the AC fixing heater HT2 is ON (step S4). ). As a result of this determination, if the AC fixing heater HT2 is not ON ("N" in Step S4), the control unit 202 turns ON the control signals S8 and S9 output to the AC heater driving circuit 205 to perform AC fixing. The heater HT2 is turned on and control is performed so that the surface temperature of the fixing roller 151 becomes the target temperature Tt (step S6). In addition, when the AC fixing heater HT2 is ON (“Y” in Step S4), the control unit 202 turns on the control signals S3 and S4 output to the capacitor charging / discharging circuit 208 to turn on the fixing roller 151. Before the surface temperature falls below Tmin, the fixing heater HT1 is turned on (step S5).
[0079]
Note that the circuit configuration of the power supply circuit with the capacitor safety measure is not limited to the configuration shown in FIG. 3, and may be another configuration. Other configuration examples 1 to 4 of the power supply circuit will be described with reference to FIGS.
[0080]
[Other configuration example 1 of the power supply circuit]
FIG. 11 is a diagram illustrating another configuration example 1 of the power supply circuit. 11, parts having the same functions as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
[0081]
11 is provided with a discharge relay RL31 for switching the connection of the capacitor CP1 between the capacitor charger 203 and the capacitor charge / discharge circuit 208 side and the discharger 210 side. When PPG1 is inserted into a commercial power outlet PSC1, the capacitor CP1 is connected to the capacitor charger 203 and the capacitor charging / discharging circuit 208, and the power plug PPG1 is not inserted into the commercial power outlet PSC1. In this case, the capacitor CP1 is connected to the discharger 210 side.
[0082]
The AC power source includes a DC power source generation circuit 204 that generates a DC power source of the image forming apparatus from a normal power outlet PSC1 through a power plug PPG1 and a main power source SW201, a capacitor charger 203 for charging the capacitor CP1, And input to the AC heater drive circuit 205.
[0083]
Discharge relay RL31 is a relay for switching connection of capacitor CP1 between capacitor charger 203 and capacitor charge / discharge circuit 208 side and discharger 210 side. Capacitor charge / discharge circuit 208 and capacitor charger 203 have a fixed (hereinafter referred to as COM) contact with capacitor CP1 via a normally open (hereinafter referred to as NO) contact of discharge relay RL31.
[0084]
A normally closed (hereinafter referred to as NC) contact of the discharge relay RL31 is connected to a capacitor discharger 203 for discharging the electric charge charged in the capacitor CP1 as an auxiliary power source.
[0085]
Normally, the discharge relay RL31 is energized to the coil of the discharge relay RL31 if the power plug PPG1 is connected to the power outlet PSC1 of the commercial power supply. The O contacts are connected, and the capacitor CP1 can be charged by the capacitor charger 203 and the capacitor charging / discharging circuit 208.
[0086]
On the other hand, in the discharge relay RL31, when the power plug PPG1 is removed from the capacitor charger 203 (unless the power plug PPG1 is connected from the power outlet PSC1), the coil of the discharge relay RL31 is energized in conjunction with the operation. Therefore, the discharge relay RL31 is turned OFF and the COM contact is N.P. From the O contact The connection is switched to the C contact, and the capacitor CP1 is disconnected from the capacitor charger 203 and the capacitor charge / discharge circuit 208 and connected to the discharger 210, and the capacitor CP1 enters a discharge state.
[0087]
According to the power supply circuit having the above configuration, the discharge relay RL31 for switching the connection of the capacitor CP1 between the capacitor charger 203 and the capacitor charge / discharge circuit 208 side and the discharger 210 side is provided, and the power plug PPG1 is a commercial power supply. When inserted into the power outlet PSC1, the capacitor CP1 is connected to the capacitor charger 203 and the capacitor charging / discharging circuit 208 side. When the power plug PPG1 is not inserted into the commercial power outlet PSC1, the capacitor Since CP1 is connected to the discharger 210 side, the electric charge remaining in the capacitor CP1 can be discharged by a simple operation without any special operation, and the maintainability of service personnel can be improved. It becomes possible to ensure the safety at the time of replacement.
[0088]
In the above configuration example, the case where the power supply plug PPG1 is interlocked with the power-off or on operation has been described. However, a normal close (NC) contact of the main power supply SW201 is provided instead of the power supply plug PPG1, and the main power supply is connected. A discharge mechanism between the capacitor CP1 and the discharger 210 may be operated in conjunction with the operation of the SW 201.
[0089]
[Other configuration example 2 of the power supply circuit]
FIG. 12 is a diagram illustrating another configuration example 2 of the power supply circuit. 12, parts having the same functions as those in FIGS. 3 and 11 are denoted by the same reference numerals, and description thereof is omitted.
[0090]
Other configuration example 2 of the power supply circuit shown in FIG. 12 has substantially the same configuration as that of FIG. 11, but is a power supply different from the main power supply of the image forming apparatus as an AC power supply supplied to the discharge relay RL31 constituting the discharge mechanism. Is used.
[0091]
The power supplied from the AC power supply ACPS1 is supplied to the DC power supply generation circuit 204 that generates the DC power supply of the image forming apparatus via the main power supply SW201, the capacitor charger 203 that charges the capacitor CP1, and the AC heater drive circuit 205. Entered.
[0092]
Discharge relay RL31 is a relay for switching connection of capacitor CP1 between capacitor charger 203 and capacitor charge / discharge circuit 208 side and discharger 210 side. Capacitor charge / discharge circuit 208 and capacitor charger 203 have a fixed (hereinafter referred to as COM) contact with capacitor CP1 via a normally open (hereinafter referred to as NO) contact of discharge relay RL31.
[0093]
A normally closed (hereinafter referred to as NC) contact of the discharge relay RL31 is connected to a discharger 210 for discharging the electric charge charged in the capacitor CP1 as an auxiliary power source.
[0094]
Further, the power of the coil of the discharge relay RL31 constituting the discharge mechanism is supplied from an AC power supply ACPS2 different from the AC power supply ACPS1. The electric power supplied from the AC power supply ACPS2 is input from the power outlet PSC1 to the coil of the discharge relay RL31 via the power plug PPG1. When the power plug PPG1 is connected to the power outlet PSC1, the discharge relay RL31 is energized with the coil of the discharge relay RL31. The O contacts are connected, and the capacitor CP1 can be charged by the capacitor charger 203 and the capacitor charging / discharging circuit 208.
[0095]
On the other hand, when the power plug PPG1 is disconnected from the power outlet PSC1 (unless the power plug PPG1 is connected from the power outlet PSC1), the discharge relay RL31 is energized to the coil of the discharge relay RL31. Therefore, the discharge relay RL31 is turned OFF and the COM contact is N.P. From the O contact The connection is switched to the C contact, and the capacitor CP1 is disconnected from the capacitor charger 203 and the capacitor charge / discharge circuit 208 and connected to the discharger 210, and the capacitor CP1 enters a discharge state.
[0096]
According to the power supply circuit having the above configuration, the discharge relay RL31 for switching the connection of the capacitor CP1 between the capacitor charger 203 and the capacitor charge / discharge circuit 208 side and the discharger 210 side is provided, and the power plug PPG1 is a commercial power supply. When inserted into the power outlet PSC1, the capacitor CP1 is connected to the capacitor charger 203 and the capacitor charging / discharging circuit 208 side. When the power plug PPG1 is not inserted into the commercial power outlet PSC1, the capacitor Since CP1 is connected to the discharger 210 side, the charge remaining in the capacitor CP1 can be discharged by a simple operation without any special operation, improving the maintainability of service personnel, and It is possible to ensure safety during replacement.
[0097]
In the above configuration example, the case where the power plug is interlocked with the power shut-off or turning-on operation has been described. However, a normal close (NC) contact of the main power SW is provided instead of the power plug, and the main power SW 201 is connected. The discharge mechanism of the capacitor CP1 and the discharger 210 may be operated in conjunction with the operation.
[0098]
[Other configuration example 3 of the power supply circuit]
FIG. 13 is a diagram illustrating another configuration example 3 of the power supply circuit. 13, parts having the same functions as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
[0099]
Another configuration example 3 of the power supply circuit shown in FIG. 13 is a configuration in which a capacitor charger 210, a capacitor discharge circuit 208, and a capacitor CP2 are connected by a connector (terminal power supply outlet box) TB1.
[0100]
In FIG. 13, a capacitor charger 203 and a capacitor charging / discharging circuit 208 are connected via a capacitor CP2 by a connector TB1. The connector TB1 is configured such that the capacitor CP2 can be attached and detached.
[0101]
FIG. 14 is a diagram for explaining the connection between the connector TB1 and the capacitor CP2 in FIG. 13. FIG. 14A is a diagram showing the connection state between the connector TB1 and the capacitor CP2, and FIG. These are figures which show the non-connecting state of connector TB1 and capacitor CP2.
[0102]
As shown in FIG. 4A, in the connector TB1, CP_H and CP_L supplied from the capacitor charger 203 are connected to the contact portions con1 and con2. A capacitor CP2 is inserted into the contact portions con1, con2, and is in a mounted state. In the mounted state, the capacitor CP2 can be charged by the capacitor charger 203 and the capacitor charge / discharge circuit 208.
[0103]
As shown in FIG. 5B, when the capacitor CP2 is pulled in the direction of the arrow, the capacitor CP2 can be detached from the connector TB1. Since the capacitor CP2 is not inserted into each of the contact portions con1 and con2 of the connector TB1, CP_H and CP_L supplied from the capacitor charger 203 are in a non-conductive state.
[0104]
In this case, the connection terminal portions TCP_H and TCP_L of the capacitor CP2 are disconnected from the capacitor charger 203 and the capacitor charge / discharge circuit 208. By this operation, the capacitor CP2 can be easily attached or detached. The connection terminal portions TCP_H and TCP_L of the capacitor CP2 may have a socket structure such as a power plug. Further, the contact parts con1 and con2 of the connector TB1 and the connection terminal parts TCP_H and TCP_L of the capacitor are preferably made of copper or a copper alloy (brass) as electrical contacts.
[0105]
According to the power supply circuit having the above configuration, the capacitor charger 210 and the capacitor discharge circuit 208 are connected to the capacitor CP2 by the connector (terminal power supply outlet box) TB1, and the capacitor CP1 is detachable from the connector TB1. Is disconnected from the connector TB1, the electrical connection between the capacitor charger 210 and the capacitor discharge circuit 208 (fixing heater HT1) is cut off, so that the auxiliary power supply can be handled by a simple attachment / detachment operation. Therefore, it is possible to easily replace the auxiliary power supply in a short time, and since the service worker does not directly contact the auxiliary power supply or the electrode part of the charger, it is possible to prevent electric shock and improve safety. It becomes possible.
[0106]
[Other configuration example 4 of the power supply circuit]
FIG. 15 is a diagram illustrating another configuration example 4 of the power supply circuit. 14, parts having the same functions as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
[0107]
Another configuration example 4 of the power supply circuit shown in FIG. 15 is a configuration in which the capacitor unit CU2 is detachably provided.
[0108]
In FIG. 15, the AC power is supplied to the DC power generation circuit 204 that generates the DC power of the image forming apparatus, the capacitor charger 203 for charging the capacitor CP2, and the AC heater driving circuit 205 via the main power SW201. Entered.
[0109]
The capacitor unit CU2 is provided between the input current detection circuit 206 and the capacitor charger 203, and the capacitor CP2 of the capacitor unit CU2 is connected to the capacitor charge / discharge circuit 208.
[0110]
FIG. 16 is a diagram illustrating a configuration example of the capacitor unit CU2 of FIG. As shown in FIG. 16, a connecting member that relays AC_L and AC_N of the AC power input to the capacitor charger 203 is provided in the capacitor unit CU2. Further, CP_H and CP_L supplied from the capacitor charger 203 are connected to each contact terminal portion in the capacitor unit CU2. By removing the capacitor unit CU2, the connection between the capacitor charger 203 and the capacitor charge / discharge circuit 208 is cut off. By this operation, the capacitor unit CU2 can be easily attached or detached.
[0111]
The capacitor unit CU2 may be provided not on the input side of the capacitor charger 203 but on the output side. The material of the connection terminal portion of the capacitor unit CU2 is preferably a material made of copper or copper alloy (brass) as an electrical contact.
[0112]
According to the power supply circuit having the above configuration, the detachable capacitor unit CU2 is provided, and when the capacitor unit CU2 is detached, the electrical connection between the capacitor charger 203 and the capacitor charge / discharge circuit 208 (fixing heater HT1). Since the auxiliary power supply can be handled with a simple attachment and detachment operation, the auxiliary power supply can be easily replaced in a short time. Since there is no direct contact with the electrode part, it is possible to prevent electric shock and improve safety.
[0113]
The present invention is not limited to the above-described embodiment, and can be appropriately modified without changing the gist of the invention.
[0114]
【The invention's effect】
  As described above, according to the image forming apparatus of the first aspect,A connecting member that relays power input from a commercial power source to the charging unit performs relaying of power from the commercial power source to the charging unit when the capacitor unit is attached to the device.When the capacitor unit is removed from the device, the power input from the commercial power source to the charging means is simultaneously cut off, and the power supply from the charging means to the capacitor is also cut off.TekiSince the power supply to the capacitor charging / discharging circuit is reliably cut off, it is possible to easily replace the auxiliary power supply in a short time, and the service personnel can directly contact the auxiliary power supply or the electrode part of the charger. Therefore, it is possible to prevent electric shock and improve safety.
[0118]
  Claims2According to the image forming apparatus,1In the invention according to the above,CapacitorsElectric double layer capacitorIsTherefore, the running cost can be reduced and the power consumption can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a mechanical configuration of an image forming apparatus to which the present invention is applied.
FIG. 2 is a diagram illustrating an internal configuration of the fixing device in FIG. 1;
FIG. 3 is a diagram illustrating a configuration of a power supply circuit of the fixing device in FIG. 1;
4 is a diagram showing a configuration of an AC heater driving circuit of FIG. 3. FIG.
5 is a diagram showing a configuration of a capacitor charge / discharge circuit of FIG. 3;
6 is a diagram showing a configuration of the discharger of FIG. 3;
7 is a diagram showing another configuration example of the discharger of FIG. 3. FIG.
FIG. 8 is a diagram illustrating a schematic configuration of a control unit in FIG. 3;
FIG. 9 is a timing chart for explaining temperature control of the fixing roller.
FIG. 10 is a flowchart for explaining ON / OFF control of the fixing heater TH1 and the AC fixing heater TH2 of the control unit;
FIG. 11 is a diagram illustrating another configuration example 1 of the power supply circuit;
FIG. 12 is a diagram showing another configuration example 2 of the power supply circuit.
FIG. 13 is a diagram illustrating another configuration example 3 of the power supply circuit.
14 is a diagram showing a configuration of a connector (terminal box) in FIG. 13;
FIG. 15 is a diagram illustrating another configuration example 4 of the power supply circuit;
16 is a diagram showing a configuration of the capacitor unit of FIG. 15;
[Explanation of symbols]
1 Image forming device
10 Automatic document feeder (ADF)
20 Image reading device
30 writing unit
40 Printer unit
121 Fixing device
151 Fixing roller
152 Pressure roller
200 Power supply circuit
201 Main power switch
202 Control unit
203 Capacitor charger
204 DC power supply generation circuit
205 AC heater drive circuit
206 Input current detection circuit
207 Interlock switch
208 Capacitor charge / discharge circuit
209 Discharge switch
210 Discharger
220 Heater ON / OFF circuit
231 Charging / discharging switch
232 Voltage detection circuit at both ends
CP1 and CP2 capacitors
CU2 capacitor unit
TH11 thermistor
HT1 fixing heater
HT2 AC fixing heater
RL11, RL21, RL31 Relay
TB1 connector

Claims (2)

In an image forming apparatus that uses a capacitor that can be charged with electric power from a commercial power source to increase the maximum supply power to the fixing device,
Charging means for charging the capacitor;
It has a connecting member for relaying the power input from the previous SL commercial power supply to the charging means, the capacitor, and a connection terminal portion for connecting the power supply line to the capacitor from the charging means, from the device A removable capacitor unit;
A capacitor charging / discharging circuit connected to the capacitor for charging / discharging the capacitor;
A controller that controls discharge of the capacitor by the capacitor charge / discharge circuit and supplies power to the fixing device, on condition that the capacitor unit is mounted on the device;
Equipped with a,
The connecting member relays electric power from the commercial power source to the charging means when the capacitor unit is attached to the device.
An image forming apparatus. The capacitor is an electric double layer capacitor,
The image forming apparatus according to claim 1.

Images