JP2004286876A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that correctly judges the life of a capacitor which is used as an auxiliary power source for a fixing device. <P>SOLUTION: The power circuit of the fixing device shown in Fig. includes: a capacitor CP1 which is an auxiliary power source that is chargeable; a capacitor charger 203 which charges the capacitor CP1; a fixing heater HT1 which is supplied with power from the capacitor CP1, thereby generating heat and heating a fixing roller 151; a capacitor charging/discharging circuit 208 which detects the charged voltage of the capacitor CP1; and a control part 202. On the basis of a thermistor TH11 for detecting the surface temperature of a fixing roller 151, the detected charged voltage of the capacitor CP1 and the detected surface temperature of the fixing roller 151, the control part 202 controls power supply from the capacitor CP 1 to the fixing heater HT1. In addition, the control part 202 judges the life of the capacitor CP1 by detecting the number of times that the capacitor CP1 is charged by the capacitor charger 203. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus such as a copier, a digital multifunction peripheral, and a printer that heats a fixing member of a fixing device using an auxiliary power supply.
[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 method is adopted from the viewpoint of high speed of 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 by heat and pressure. Many are adopted. In the heat roll method, a heat roller heated by a heat generating member such as a halogen heater and a pressure roller arranged opposite to the heat roller are pressed against each other to form a mutual press contact portion called a nip portion, and a toner image is formed on the nip portion. Is a method of heating through a recording medium on which is transferred.
[0003]
In recent years, environmental issues have become important, and image forming apparatuses such as copiers and printers have also been saving energy. In considering the energy saving of this image forming apparatus, it cannot be ignored that fixing apparatuses for fixing toner onto a recording medium are not negligible. It is power saving.
[0004]
For example, Japanese Patent Application Laid-Open No. H11-163873 proposes a technology that achieves energy saving by increasing the maximum power supply by using an auxiliary power supply for a fixing device. The fixing device disclosed in Patent Document 1 supplies electric power from a main power supply device and a secondary battery or a primary battery at the time of startup, and uses a cadonica battery or a lead battery as a secondary power source. I have. Such a secondary battery has the property that the capacity deteriorates and decreases when charging and discharging are repeated many times, and the life is shortened as discharging with a large current. In general, even for a CADNICA battery that is considered to have a long life at a large current, the number of charge / discharge repetitions is about 500 to 1000 times, and if the charge / discharge is repeated 20 times a day, the battery life will be about one month. I'm sorry. Therefore, there is a disadvantage that the replacement is troublesome and the running cost such as the replacement battery cost is very high. Furthermore, lead storage batteries are not preferred as office equipment such as those using liquid sulfuric acid.
[0005]
For this reason, an image forming apparatus using a large-capacity capacitor such as an electric double-layer capacitor as an auxiliary power supply of a fixing device is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-163,837. Such an electric double-layer capacitor has a charge / discharge repetition frequency of tens of thousands to hundreds of thousands or more and has a much longer life due to the number of times of charging / discharging than a battery. Not enough times.
[0006]
Here, the life of the capacitor means that the capacitance of the capacitor decreases. When the capacitance of the capacitor decreases, the original power cannot be obtained, so that the fixing temperature may not be able to maintain the target temperature depending on the use environment, transfer paper material, and copy mode. For example, when the capacitor power is used during the continuous copy operation, a drop in the surface temperature of the fixing roller occurs during the continuous copy operation. Further, when the capacitor power is used to assist the rise of the surface temperature of the fixing roller, adverse effects such as a longer rise time occur.
[0007]
When the life of the capacitor has expired, the copying operation cannot be completely stopped.However, as described above, the original device performance cannot be achieved, so the capacitor needs to be replaced when the life of the capacitor has expired. There is. Therefore, in order to maintain the performance of the image forming apparatus, it is necessary to accurately determine the life of the capacitor.
[0008]
[Patent Document 1]
JP-A-10-282821
[Patent Document 2]
JP-A-2002-184554
[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 capable of accurately determining the life of a capacitor used as an auxiliary power supply of a fixing device.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an invention according to claim 1 is an image forming apparatus including a fixing device for thermally fixing a toner image with a fixing member, wherein an auxiliary power supply including a chargeable and dischargeable capacitor; Charging means for charging a power supply, a heating member heated by the power supplied from the auxiliary power supply and heating the fixing member, voltage detecting means for detecting a charging voltage of the auxiliary power supply, and a surface temperature of the fixing member Temperature detecting means for detecting the voltage of the auxiliary power supply detected by the voltage detecting means and the surface temperature of the fixing member detected by the temperature detecting means, from the auxiliary power supply to the heating member Power control means for controlling power supply; and auxiliary power supply life detecting means for detecting the number of times the auxiliary power supply is charged by the charging means to determine the life of the auxiliary power supply. The features.
[0011]
According to the invention, the auxiliary power supply is configured by a chargeable capacitor, the charging unit charges the auxiliary power supply, and the heat generating member is supplied with power from the auxiliary power supply to generate heat, and heats the fixing member. The voltage detecting means detects the charging voltage of the auxiliary power supply, the temperature detecting means detects the surface temperature of the fixing member, and the power control means detects the charging voltage of the auxiliary power supply detected by the voltage detecting means and the temperature detecting means. Based on the detected surface temperature of the fixing member, the supply of power from the auxiliary power supply to the heat generating member is controlled, and the auxiliary power supply life detecting means detects the number of times the auxiliary power supply is charged by the charging means, and Judge life expectancy.
[0012]
Further, in the image forming apparatus according to the second aspect, in the image forming apparatus according to the first aspect, the auxiliary power supply life detecting unit determines a life of the auxiliary power supply when a detected number of times of charging is equal to or more than a predetermined number. It is characterized by determining that there is.
[0013]
According to the invention, the auxiliary power supply life detecting means determines that the auxiliary power supply has reached the end of life when the detected number of times of charging is equal to or more than the predetermined number of times.
[0014]
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, a predetermined warning is provided when the life of the auxiliary power supply is detected by the auxiliary power supply life detecting means. Is provided.
[0015]
According to the invention, the warning means issues a predetermined warning when the life of the auxiliary power supply is detected by the auxiliary power supply life detecting means.
[0016]
In the image forming apparatus according to a fourth aspect, in the image forming apparatus according to the third aspect, when the life of the auxiliary power supply is detected by the auxiliary power supply life detection means, It is characterized by displaying that the life of the auxiliary power supply is detected and issuing a warning.
[0017]
According to the invention, when the life of the auxiliary power supply is detected by the auxiliary power supply life detecting means, the warning means displays a warning that the life of the auxiliary power supply is detected on the operation unit to give a warning.
[0018]
In the image forming apparatus according to a fifth aspect, in the invention according to the second aspect, the warning unit is connected via a network when the auxiliary power source life detecting unit determines that the auxiliary power source has reached the end of its life. A predetermined warning is notified to the service center.
[0019]
According to the above invention, the warning means notifies the service center connected via the network of a predetermined warning when the life of the auxiliary power supply is determined by the auxiliary power supply life detecting means.
[0020]
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the auxiliary power supply includes an electric double layer capacitor.
[0021]
According to the invention, the electric double layer capacitor is used as the auxiliary power supply.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of an image forming apparatus according to the present invention will be described in detail in the order of (Embodiment 1) and (Embodiment 2) with reference to the drawings.
[0023]
(Embodiment 1)
An image forming apparatus according to a first embodiment will be described with reference to FIGS.
[0024]
[Overall Configuration of Image Forming Apparatus]
FIG. 1 is a sectional view showing a schematic mechanical configuration of an image forming apparatus to which the present invention is applied. The image forming apparatus 1 shown in FIG. 1 is composed of a digital multifunction peripheral, and has a copying function, a printer function, a facsimile function, and the like. A copy function, a printer function, and a facsimile function can be sequentially switched and selected by an application switching key of the operation unit (see FIG. 2). When a copy function is selected, a copy mode is set, and a printer function is selected. Sometimes, the print mode is set, and when the facsimile mode is selected, the facsimile mode is set.
[0025]
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 transmits image information of the document conveyed to the document reading position. An image reading device 20 for optically reading, a writing unit 30 for writing image information of the read original to the printer unit 40, and a toner image of the image information of the original written by the writing unit 30 for forming a toner image such as transfer paper A printer unit 40 for transferring the image onto a transfer material and discharging the image.
[0026]
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 with its image side up is pressed when the start key on the operation unit is pressed, and the lowermost document is fed to the feed roller. The sheet is fed to a predetermined position on the contact glass 105 by the feed belt 103 and the feed belt 104. The ADF 10 has a counting function that counts up the number of documents each time the feeding of one document is completed. The document on the contact glass 105 is discharged onto a paper discharge table 108 by a feed belt 104 and a discharge roller 107 after image information is read by an image reading device 20 as image input means.
[0027]
When the document set detector 109 detects that the next document exists on the document table 102, the lowermost document on the document table 102 is similarly moved by the paper feed roller 103 and the feeding belt 104. The sheet is fed to a predetermined position on the contact glass 105. After the image information is read by the image reading device 20, the document on the contact glass 105 is discharged onto a discharge tray 108 by a feed belt 104 and a 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).
[0028]
When selected, the first paper supply device 110, the second paper supply device 111, and the third paper supply device 112 are loaded on the first tray 113, the second tray 114, and the third tray 115, respectively. A sheet of transfer paper as the transferred material is fed, and the transfer paper is transported by a vertical transport unit 116 to a position where it comes into contact with a photoreceptor 117 as an image carrier. The photoconductor 117 uses a photoconductor drum, for example, and is driven to rotate by a main motor (not shown).
[0029]
Image information of a document 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 to optical 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.
[0030]
The transport belt 120 also serves as a paper transport unit and a transfer unit, and a transfer bias is applied from a power supply. The transport belt 120 transports the transfer paper transported from the vertical transport unit 116 at a constant speed to the photosensitive drum 117 on the photosensitive drum 117. Is transferred to a transfer sheet. The transfer sheet is fixed with a toner image by a fixing device 121, and is discharged to a discharge tray 123 by a discharge unit 122. The photosensitive drum 117 is cleaned by a cleaning device (not shown) after the transfer of the toner image. 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.
[0031]
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 two-sided mode, the operation is performed using one of the paper feed trays 113 to 115. The transfer paper fed and having the image formed on the surface as described above is switched by the paper discharge unit 122 to the double-sided paper conveyance path 124 instead of the paper discharge tray 123, and is switched back by the reversing unit 125. The sheet is reversed and transported to the duplex transport unit 126.
[0032]
The transfer paper conveyed to the double-sided conveyance unit 126 is conveyed to the vertical conveyance unit 116 by the double-sided conveyance unit 126 and conveyed to a position where the transfer paper comes into contact with the photosensitive drum 117 by the vertical conveyance unit 116, and then on the photosensitive drum 117. Then, the 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, thereby forming a two-sided copy. The two-sided copy is discharged to a discharge tray 123 by a discharge unit 122.
[0033]
When the transfer sheet is inverted and discharged, the transfer sheet that has been switched back by the reversing unit 125 and turned upside down is not conveyed to the double-sided conveyance unit 126 but is discharged through the reversing discharge conveyance path 127. The paper is discharged to the paper discharge tray 123 by the unit 122.
[0034]
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 a transfer sheet by the image forming means. Further, in the facsimile mode, image information from the image reading unit is transmitted to the other party by a facsimile transmitting / receiving unit (not shown), and the image information from the other party is received by the facsimile transmitting / receiving unit instead of the image information from the image processing unit. By being input to the writing unit 30, an image is formed on transfer paper by the above-described image forming means.
[0035]
FIG. 2 is a diagram illustrating a schematic configuration of an operation unit of the image forming apparatus of FIG. As shown in FIG. 2, the operation unit 130 includes an LCD 131 with a touch panel for displaying necessary information and function keys, a KEY 132 including mechanical keys such as a start key and numeric keys, an LED, and the like.
[0036]
[Configuration of fixing device]
FIG. 3 is a diagram showing an internal configuration of the fixing device 121 of FIG. The fixing device 121 illustrated in FIG. 2 includes a fixing roller 151 serving as a fixing member, a pressing roller 152 serving as a pressing member that presses the fixing roller 151, and a fixing roller 151. The heating is performed by an AC fixing heater HT2 serving as a main heating element and a fixing heater HT1 serving as an auxiliary heating element, and a temperature detecting 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 certain thermistor TH11.
[0037]
The fixing roller 151 is made of an elastic member such as silicone rubber, and heat-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 pressing force by a pressing unit (not shown). As the fixing heater HT1 and the AC fixing heater HT2, halogen heaters are generally used, but other resistors may be used. The AC fixing heater HT2 is supplied with AC power from an AC heater driving circuit (see FIG. 4) to generate heat (lights up), and the fixing heater HT1 is supplied with a voltage from a capacitor (see FIG. 4) as an auxiliary power supply to generate heat. (Light.
[0038]
In the fixing device 121 having the above configuration, the fixing roller 151 and the pressure roller 152 are rotationally driven by a driving mechanism (not shown), and the sheet P such as the transfer paper carrying the toner Toner is fixed to the fixing roller 151 and the pressure roller 152 by the driving mechanism. 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 pressing roller 152.
[0039]
Note that, here, the fixing member and the pressing member are generally rollers as shown in FIG. 3, but are not limited to rollers, and an endless belt or the like is used for one or both of them. May be. Further, the fixing heaters HT1 and the AC fixing heater HT2 are arranged inside the fixing roller 151, but may be arranged at any position as long as the fixing roller 151 can be heated.
[0040]
[Power circuit of fixing device]
FIG. 4 is a diagram illustrating a configuration of a power supply circuit of the fixing device. A power supply circuit 200 of the fixing device shown in FIG. 4 includes a main power supply SW201 for turning on / off the supply of AC power, a control unit 202 for controlling each unit of the image forming apparatus and the power supply circuit 200, and a device for charging the capacitor CP. , A DC power supply generating circuit 204 for generating DC power for the image forming apparatus, an AC heater driving circuit 205 for supplying AC power to the AC fixing heater HT2, and detecting an input current input from the AC power supply An input 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, and a capacitor CP1 that is an auxiliary power supply of the fixing heater HT1. Have.
[0041]
The AC power supply supplies AC power to the AC heater drive circuit 205, the DC power generation circuit 205, and the capacitor charger 203 via the main power supply SW 201 and the input current detection circuit 206.
[0042]
The control unit 202 controls each unit of the power supply circuit 200, and controls operations of the capacitor charger 203, the AC heater drive circuit 205, and the capacitor charge / discharge circuit 208. Specifically, control unit 202 sends control signal S1 to capacitor charger 203 to control the charging operation of capacitor CP1 by capacitor charger 203. Further, the control unit 202 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. Further, the control unit 202 sends control signals S8 and S9 to the AC heater drive circuit 205 to control the ON / OFF operation of the fixing heater HT2 by the AC heater drive circuit 205. Further, control unit 202 counts the number of times T that capacitor CP1 has been charged by capacitor charger 203 to determine the life of capacitor CP1 (see FIG. 10).
[0043]
The input current detection circuit 206 is provided between the main power supply SW 201, the AC heater drive circuit 205, the DC power supply generation circuit 204, and the capacitor charger 203. The input current of the AC power supply input via the main power supply SW 201 is provided. And outputs the detected current S7 to the control unit 202. This input current fluctuates according to the operation states of the AC heater driving circuit 205, the DC power generation circuit 204, the capacitor charger 203, and the image forming apparatus.
[0044]
A DC power generation circuit 204 is used for a power supply Vcc mainly used in a control system inside the image forming apparatus, and mainly used for a drive system and a medium-high voltage power supply, based on an AC power supply input via a main power supply SW 201. The power supply Vaa is generated and output to each unit.
[0045]
The interlock switch 207 is a switch that is turned on / off in conjunction with covers of the image forming apparatus (not shown), and is a driving member that can be touched when the covers of the image forming apparatus are opened, and a medium / high voltage power supply member. When the cover is opened, the power supply is shut off so as to stop the operation of the drive member or stop the voltage application to the application member when the cover is opened. A part of the power supply Vaa generated by the DC power supply generation circuit 204 is input to the interlock switch 207, and is input to the capacitor charge / discharge circuit 208 and the AC heater drive circuit 205 via the interlock switch 207.
[0046]
The AC heater driving circuit 205 turns ON / OFF the AC fixing heater HT2 according to the control signals S8 and S9 input from the control unit 202.
[0047]
The capacitor charger 203 is connected to the capacitor CP1, and charges the capacitor CP1 based on a control signal S1 input from the control unit 202.
[0048]
The capacitor CP1 is configured by 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 power is supplied to the fixing heater HT1 by ON / OFF control of the capacitor charge / discharge circuit 208. Supplied to
[0049]
The capacitor charging / discharging circuit 208 discharges the power stored in the capacitor CP1 according to the control signals S3 and S4 input from the control unit 202, and turns ON / OFF the fixing heater HT1.
[0050]
The thermistor TH11 is provided near 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 with 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]
[AC heater drive circuit]
FIG. 5 is a diagram showing a configuration of the AC heater drive circuit 205 of FIG. The AC heater drive circuit 205 includes a filter FIL21 for removing noise of the input AC power, a fixing relay RL21 for safety protection that is turned on / off in response to a control signal S9 input from the control unit 202, It comprises a diode D21 for preventing back-up of the protection fixing relay RL21, and a heater ON / OFF circuit 220 for turning ON / OFF the AC fixing heater HT2 based on a control signal S8 input from the control unit 202. ing.
[0052]
The AC power supply is connected to one end of the fixing heater HT2 via a filter FIL21 and a fixing relay RL21 for safety protection. The other end of the fixing heater HT2 is connected to a heater ON / OFF circuit 220.
[0053]
The heater ON / OFF circuit 220 includes a triac TRI21 for turning on / off the AC power, a gate of the triac TRI21, and a photocoupler PC21 for insulating a signal from the control unit 202 on the secondary side. A transistor TR21 for driving a 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 follow-current prevention resistor. Resistors R23 and R24, which are current limiting resistors of the photocoupler PC21.
[0054]
In the AC heater driving circuit 205 having the above configuration, the AC fixing heater HT2 is supplied with electric power and turned on in a state where both the fixing relay RL21 for safety protection and the gate of the transistor TR21 are turned on.
[0055]
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 ON, and performs AC fixing. Controls on / off of the heater HT2.
[0056]
[Configuration of capacitor charge / discharge circuit]
FIG. 6 is a diagram showing a configuration of the capacitor charge / discharge circuit 208 of FIG. As shown in FIG. 6, the capacitor charge / discharge circuit 208 detects a charge / discharge switch 231, a fixing relay RL 11 for safety protection, a diode D 11 for preventing a back electromotive of the fixing relay RL 11, and a voltage across the capacitor CP 1. And a voltage detection circuit 232 for both ends.
[0057]
Both ends of the capacitor CP1 are connected to a charging / discharging switch 231 and a fixing relay RL11 for safety protection. The charge / discharge switch 231 is turned on / off by a control signal S3 input from the control unit 202. Similarly, the fixing relay RL11 for safety protection is turned on / off by a control signal S4 input from the control unit 202.
[0058]
When both the charge / discharge 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 power is supplied.
[0059]
The both-ends voltage detection circuit 232 detects the voltage between both ends 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 state of charge of the capacitor CP1.
[0060]
[Configuration of control unit]
FIG. 7 is a diagram showing a schematic configuration of the control unit 202 in FIG. The control unit 202 includes a CPU 241, a memory 242, and the like.
[0061]
The CPU 241 is connected to a memory 242 for storing a program and data for controlling the image forming apparatus, and controls the image forming apparatus and the power supply circuit 200 based on the program stored in the memory 242.
[0062]
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 charge / discharge circuit 208, a thermistor TH11 for detecting the surface temperature of the fixing roller 151, and a resistor R41. And a detection current (analog signal) S7 obtained by detecting an input current of the image forming apparatus by the input current detection circuit 206, and the like.
[0063]
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 charge / discharge switch 231 and the fixing relay RL11 for safety protection via the IO port. It outputs 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.
[0064]
Further, the CPU 241 is configured to control the operation unit 130, and monitors an input of the KEY 132 provided on the operation unit 130. The DRV 243 is a driver for driving the LCD 11, and the DRV 244 is a driver for driving the LED 133, and is driven and controlled by the CPU 241.
[0065]
[Temperature control of fixing roller]
FIG. 8 is a timing chart for explaining the temperature control of the fixing roller 151. 2A shows the surface temperature T of the fixing roller 151, FIG. 2B shows the detected current (input current) I detected by the input current detection circuit 206, and FIG. 2C shows the AC fixing heater HT2. (D) shows the timing of discharging the capacitor CP1.
[0066]
Further, in the figure, a period t1 is a start-up period of the image forming apparatus (fixing roller 151), a period t2 is a standby period of the image forming apparatus, a period t3 is a copy operation period, a period t4 is a standby period of the image forming apparatus, and a period t5 indicates a period of the low power mode, and period t6 indicates a period of the energy saving mode.
[0067]
In FIG. 8, first, 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 supply to an AC fixing heater HT2, which is a heating member, and the fixing roller 151 is overheated as shown in FIG. In this period t1, the AC fixing heater HT2 is turned on at full duty, but the copying operation is not performed, so that the input current I becomes equal to or less than the maximum input current Imax as shown in FIG. I have.
[0068]
When the surface temperature of the fixing roller 151 detected by the thermistor TH11 reaches the target temperature Tt at which the copying operation can be performed, the power supply to the AC fixing heater HT2 is stopped, the start-up period t1 ends, and copy standby is performed. The state transits to the state (t2 period).
[0069]
In the period t2, the control unit 202 repeatedly turns on when the temperature falls below the target temperature Tt and turns off when the temperature reaches the target temperature Tt while monitoring the surface temperature of the fixing roller 151. In the period t2, even if the surface temperature of the fixing roller 151 has reached 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 the copy, as in the period t3, the AC starts. Even when the fixing heater HT2 is turned on, 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 lower than the target temperature Tt. However, when the surface temperature of the fixing roller 151 becomes lower than Tmin, the fixing property cannot be ensured. I have to do it.
[0070]
During the copy operation in the period t3, the input current I of the DC power supply generation circuit 204 increases with an increase in the load current on the DC power supply side, and the input current of the entire device also increases as shown in FIG. As a result, the power consumption of the entire device also increases, and may reach the maximum input current Imax defined for the device. The maximum input current Imax cannot be exceeded due to device specifications. For this reason, in the period t3, the lighting rate of the AC fixing heater HT2 cannot be further increased as shown in FIG. 9C, so that the surface temperature of the fixing roller 151 does not fall below Tmin as in the period t4. In this case, the surface temperature of the fixing roller 151 is increased by discharging the electric power charged in the capacitor (CP1) to the fixing heater HT1 provided separately from the AC fixing heater HT2.
[0071]
The period t4 is a standby period after the end of the copying operation. As in the case of the period t2, the capacitor CP1 is discharged to supply power to the fixing heater HT1 as shown in FIG. If the surface temperature of the fixing roller 151 reaches the target temperature Tt, the discharge of the capacitor CP1 is stopped, as shown in FIG.
[0072]
In the period t5, even when the discharge supply from the capacitor CP1 is stopped, as in the period t6, when the surface temperature of the fixing roller 151 can be maintained at the target temperature Tt only by the AC fixing heater HT2, the AC fixing heater HT2 is not used. Is ON / OFF controlled to control the temperature of the fixing roller 151.
[0073]
FIG. 9 is a flowchart for explaining ON / OFF control of the fixing heater TH1 and the AC fixing heater TH2 by the control unit 202. With reference to FIG. 9, ON / OFF control of the fixing heater TH1 and the AC fixing heater TH2 of the control unit 202 will be described.
[0074]
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 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. To turn off the fixing heater HT1 (step S2), and turn off the control signals S8 and S9 output to the AC heater drive circuit 205 to turn off the AC fixing heater HT2 (step S3).
[0075]
On the other hand, when the surface temperature of the fixing roller 151 is not higher than the target temperature Tt (“N” in step S1), the control unit 202 first determines whether the AC fixing heater HT2 is turned on (step S4). ). As a result of this determination, when the AC fixing heater HT2 is not turned 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 turn on the AC fixing heater HT2. The heater HT2 is turned on to control the surface temperature of the fixing roller 151 to the target temperature Tt (step S6). When the AC fixing heater HT2 is on (“Y” in step S4), the control unit 202 turns on the control signals S8 and S9 output to the capacitor charging / discharging circuit 208 to turn on the fixing roller 151. Before the surface temperature becomes equal to or lower than Tmin, the fixing heater HT1 is turned on (step S5).
[0076]
[Capacitor life determination process]
FIG. 10 is a flowchart illustrating a process in which the control unit 202 determines the life of the capacitor CP1. A process in which the control unit 202 determines the life of the capacitor CP1 will be described with reference to FIG. As described above, in order to maintain the surface temperature of the fixing roller 151, the electric power is discharged from the capacitor CP1 to the fixing heater TH1, but must be charged after being discharged. Control unit 202 counts the number of times that capacitor CP1 has been charged, and determines the life of capacitor CP1.
[0077]
The control unit 202 constantly monitors the voltage across the capacitor CP1, and determines whether or not the voltage signal S5 detected by the voltage detection circuit 232 across the capacitor charge / discharge circuit 208 is equal to or higher than a predetermined voltage value. (Step S11). As a result of this determination, when the voltage signal S5 is not equal to or higher than the predetermined voltage value ("N" in step S11), the control unit 202 determines that the detection current S7 detected by the input current detection circuit 206 is equal to the maximum input current Imax. Is determined (step S12).
[0078]
As a result of this determination, when the detected current S7 is not the maximum input current Imax (“Y” in step S11), the control unit 202 turns on the control signal S1 output to the capacitor charger 203, and The capacitor CP1 is charged (step S13). As described above, since the maximum input current Imax of the device cannot be exceeded even during charging, the detection current S7 input from the input current detection circuit 206 is monitored, and the capacitor CP1 is charged only when charging is possible. I have.
[0079]
Then, the control unit 202 counts up the number of times of charging T (T = T + 1) every time the capacitor CP1 is charged (step S14), and stores the number of times of charging T in the memory 242. The control unit 202 determines whether or not the number of charges T is equal to or greater than a predetermined number N determined by the capacitor CP1 (step S15). If the number of charges T is equal to or greater than the predetermined number N (step S15). Y "), the life of the capacitor is determined, and a message such as" It is time to replace the capacitor "or" Please contact service "is displayed on the LCD 131 of the operation unit 130 as a warning to that effect (step S16). On the other hand, if the charging count T is not equal to or greater than the predetermined count N (“N” in step S15), the process returns.
[0080]
As described above, according to the image forming apparatus of the first embodiment, control unit 202 detects the number of times that capacitor CP1 has been charged by capacitor charger 203, and determines that the number of times of charging has reached predetermined value N or more. , The life of the capacitor CP1 can be easily and accurately detected.
[0081]
Further, when detecting the life of the capacitor CP1, the control unit 202 displays a predetermined warning on the liquid crystal LCD 131 of the operation unit 130. Therefore, the control unit 202 has the configuration of the conventional image forming apparatus without any special configuration. It is possible to notify a warning by an inexpensive method.
[0082]
(Embodiment 2)
An image forming apparatus according to a second embodiment will be described with reference to FIGS. The image forming apparatus according to the second embodiment has a network connection function, and is configured to notify a service center via a network when the life of the capacitor CP1 is detected.
[0083]
The image forming apparatus according to the second embodiment is the same as the first embodiment except that the image forming apparatus has a network connection function, and a description thereof will be omitted.
[0084]
FIG. 12 illustrates a network configuration example of the image forming apparatus according to the second embodiment. In the figure, reference numeral 300 denotes a LAN, 400 denotes a network such as the Internet, and the LAN 300 is connected to the network 400.
[0085]
A service center server (hereinafter, referred to as “service center”) 600 is connected to the network 400. A service person or the like is waiting at the service center. The image forming apparatus (digital multifunction peripheral) 1 according to the second embodiment, four terminal computers A to D, a network server 500 that manages an interface in the LAN 300, and a printer F are connected to the LAN 300. .
[0086]
In the LAN 300, a user can print out from the terminal computers A, B, C, and D to the printer E or the image forming apparatus 1 via the network server 500. The terminals in the LAN 300 are connected by an I / F cable. In the LAN 300, commands and data are transmitted and received between terminals via an I / F cable. Further, the terminal computers A, B, C, D, the printer E, and the image forming apparatus 1 can perform data communication with the service center 600 via the network server 500.
[0087]
FIG. 12 is a diagram illustrating a schematic configuration of the control unit 202 of the image forming apparatus according to the second embodiment. The control unit 202 controls the I / F in addition to the configuration in FIG. 7, and is connected to the network server 500 via the I / F 245.
[0088]
FIG. 13 is a flowchart illustrating a process in which the control unit 202 of the image forming apparatus according to the second embodiment determines the life of the capacitor CP1. In FIG. 13, portions performing the same processes as those in FIG. 10 are denoted by the same reference numerals, description thereof will be omitted, and only different processes will be described.
[0089]
In FIG. 13, when the number of charges T is equal to or greater than the predetermined number N (“Y” in step S15), the control unit 202 determines that the life of the capacitor CP1 has expired and connects to the network via the network server 500. A warning to that effect is sent to the service center 600 (step S21). On the other hand, if the charging count T is not equal to or greater than the predetermined count N (“N” in step S15), the process returns.
[0090]
As described above, according to the image forming apparatus of the second embodiment, when the control unit 202 detects the life of the capacitor CP1, the control unit 202 notifies the service center 600 via the network. It is possible to notify the service center of the replacement of the capacitor, and it is possible to save the user the trouble of contacting the service center 600.
[0091]
The present invention is not limited to the above-described embodiment, and can be appropriately modified without changing the gist of the invention.
[0092]
【The invention's effect】
As described above, according to the image forming apparatus of the first aspect, in an image forming apparatus including a fixing device that thermally fixes a toner image with a fixing member, the auxiliary power supply including a chargeable capacitor; Charging means for charging an auxiliary power supply, a heat generating member for receiving power from the auxiliary power supply and generating heat to heat the fixing member, voltage detecting means for detecting a charging voltage of the auxiliary power supply, and a surface of the fixing member A temperature detection unit for detecting a temperature, and a charging voltage of the auxiliary power supply detected by the voltage detection unit and a surface temperature of the fixing member detected by the temperature detection unit. Power control means for controlling the supply of electric power, and auxiliary power supply life detecting means for detecting the number of times the auxiliary power supply is charged by the charging means and determining the life of the auxiliary power supply. Since it was decided was example, it is possible to determine the lifetime of the capacitor used as an auxiliary power source of the fixing device with high accuracy.
[0093]
Further, according to the image forming apparatus of the second aspect, in the image forming apparatus of the first aspect, the auxiliary power supply life detecting unit is configured to switch the auxiliary power supply when the detected number of times of charging is equal to or more than a predetermined number. Since the life is determined, it is possible to easily determine the life of the capacitor used as the auxiliary power supply of the fixing device.
[0094]
Further, according to the image forming apparatus of the third aspect, in the image forming apparatus of the first or second aspect, when the life of the auxiliary power supply is detected by the auxiliary power supply life detecting means, the predetermined time can be reduced. Is provided, the user can be notified of the service life of the auxiliary power supply.
[0095]
According to the image forming apparatus of the fourth aspect, in the image forming apparatus of the third aspect, the warning unit may be configured to operate the operation unit when the auxiliary power supply life detecting unit detects the life of the auxiliary power supply. Warning that the life of the auxiliary power supply has been detected is displayed, so that it is possible to notify the warning in an inexpensive manner with the configuration of the conventional image forming apparatus without having a special configuration. Become.
[0096]
According to the image forming apparatus of the fifth aspect, in the image forming apparatus of the third aspect, when the auxiliary power source life detecting unit determines that the life of the auxiliary power source is determined, the warning unit sets the network. A predetermined warning is notified to the service center connected via the switch, so that the capacitor replacement can be automatically notified to the service center, eliminating the need for the user to contact the service center. It becomes.
[0097]
According to the image forming apparatus of the sixth aspect, in the image forming apparatus of any one of the first to fifth aspects, the auxiliary power supply is constituted by an electric double layer capacitor. In addition, 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 illustrating a mechanical configuration of an image forming apparatus to which the present invention is applied.
FIG. 2 is a diagram illustrating a schematic configuration of an operation unit of the image forming apparatus of FIG. 1;
FIG. 3 is a diagram illustrating an internal configuration of the fixing device of FIG. 1;
FIG. 4 is a diagram illustrating a configuration of a power supply circuit of the fixing device of FIG. 1;
FIG. 5 is a diagram illustrating a configuration of an AC heater drive circuit of FIG. 4;
FIG. 6 is a diagram showing a configuration of a capacitor charge / discharge circuit of FIG. 4;
FIG. 7 is a diagram illustrating a schematic configuration of a control unit in FIG. 4;
FIG. 8 is a diagram showing a timing chart for explaining temperature control of a fixing roller.
FIG. 9 is a flowchart illustrating ON / OFF control of the fixing heaters TH1 and TH2 by the control unit.
FIG. 10 is a flowchart illustrating a capacitor life determining process of a control unit.
FIG. 11 is a diagram illustrating a schematic configuration of a control unit of the image forming apparatus according to the second embodiment;
FIG. 12 is a diagram illustrating a configuration example of a network of an image forming apparatus according to a second embodiment;
FIG. 13 is a diagram illustrating a flowchart for explaining capacitor life determination processing of a control unit according to the second embodiment.
[Explanation of symbols]
1 Image forming apparatus
10 Automatic Document Feeder (ADF)
20 Image reading device
30 writing unit
40 Printer unit
121 fusing unit
155 fixing roller
200 power supply circuit
201 Main power switch
202 control unit
203 capacitor charger
204 DC power generation circuit
205 AC heater drive circuit
206 Input current detection circuit
207 Interlock switch
208 Capacitor charge / discharge circuit
220 Heater ON / OFF circuit
231 Charge / discharge switch
232 Voltage detection circuit at both ends
CP1 capacitor
TH1 thermistor
HT1 fixing heater
HT2 AC fixing heater
RL11, RL21 Fixing relay

Claims (6)

In an image forming apparatus including a fixing device that thermally fixes a toner image with a fixing member,
An auxiliary power supply composed of a chargeable capacitor;
Charging means for charging the auxiliary power supply;
A heating member that generates heat when supplied with power from the auxiliary power supply and heats the fixing member;
Voltage detection means for detecting a charging voltage of the auxiliary power supply,
Temperature detection means for detecting the surface temperature of the fixing member,
Power control for controlling supply of power from the auxiliary power supply to the heating member based on the charging voltage of the auxiliary power supply detected by the voltage detection means and the surface temperature of the fixing member detected by the temperature detection means Means,
Auxiliary power supply life detecting means for detecting the number of times the auxiliary power supply is charged by the charging means and determining the life of the auxiliary power supply;
An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the auxiliary power supply life detecting unit determines that the auxiliary power supply has reached the end of life when the number of times of charging detected is equal to or more than a predetermined number of times. 3. The image forming apparatus according to claim 1, further comprising a warning unit that issues a predetermined warning when the life of the auxiliary power supply is detected by the auxiliary power supply life detection unit. The warning means, when the life of the auxiliary power supply is detected by the auxiliary power supply life detecting means, displays a warning that the life of the auxiliary power supply is detected on an operation unit to give a warning. Item 4. The image forming apparatus according to Item 3. 4. The warning device according to claim 3, wherein when the auxiliary power supply life detecting device determines that the auxiliary power supply has reached the end of its life, the warning unit notifies a service center connected via a network of a predetermined warning. The image forming apparatus as described in the above. The image forming apparatus according to claim 1, wherein the auxiliary power supply includes an electric double layer capacitor.

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