JP4390142B2 - Image forming apparatus - Google Patents

Description

The present invention relates to a copying machine, a printer, a facsimile, or a composite machine including a power storage device configured to be chargeable / dischargeable and configured to supply electric power discharged to a power-supplied member and a fixing device as a power-supplied member. those related to the image forming apparatus and the like.

  Conventionally, in an image forming apparatus using an electrophotographic method such as a copying machine, the temperature rise time at the start-up of the fixing device is shortened to improve operability, and the power consumed by the fixing device is reduced. For the purpose of achieving energy saving and the like, a technique for installing a power storage device separately from a main power source is known (for example, see Patent Document 1).

Specifically, the fixing device mainly includes a fixing roller in which a heating member such as a heater is provided, and a pressure roller in pressure contact with the fixing roller.
On the other hand, the toner image is transferred onto the surface of the recording medium that moves along the conveyance path of the image forming apparatus at the image forming unit. The recording medium carrying the unfixed toner image further moves on the transport path at a predetermined transport speed and reaches the fixing device. The recording medium that has reached the fixing device is fed between the fixing roller and the pressure roller (a nip), and the toner image is fixed by the heat received from the fixing roller and the pressure received from both rollers. . The recording medium on which the toner image is fixed is delivered from between the fixing roller and the pressure roller and then discharged from the image forming apparatus.

On the other hand, the main body of the image forming apparatus is provided with a main power source that is connected to a commercial power source and supplies power to a power-supplied body such as a fixing device in the main body. Further, the main body of the apparatus is provided with a power storage device as an auxiliary power source that appropriately supplies power (discharge power) to the fixing device, in addition to the main power source.
The power storage device includes a capacitor unit (cell unit) for charging / discharging electric power, a switching unit for switching charging / discharging of the capacitor unit, and rectifying AC power supplied from the main power supply and converting the DC power into a capacitor. A charging unit to be supplied to the unit, an element such as an FET, a connection terminal for connecting to a power supply body, and the like are electrically connected.

  When the main power switch of the image forming apparatus is turned on (when the image forming apparatus is started up), power is supplied from the commercial power source to the fixing device via the main power source, and fixing is also performed from the power storage device. Power is supplied to the device. As a result, in addition to the rated power of the commercial power source (for example, 100V15A) supplied from the main power source, the fixing device is supplied with power from the power storage device, and the fixing roller can quickly reach the desired temperature ( The fixing temperature is reached. Therefore, even when starting up an image forming apparatus in which the main power switch is disconnected for a long time and the temperature of the fixing roller is lowered, the start-up is completed in a relatively short time. The operability is improved and the fixing temperature during standby can be set lower, so that the power consumption of the apparatus is reduced.

In addition, when the image forming apparatus main body consumes a large amount of power even when the image forming apparatus is not started up (for example, when the document reading unit is operating, when image formation is continuously performed, Also when starting up from a long standby state, etc.), the power storage device supplies power to the fixing device. In such a case, the shortage of power supplied from the main power source to the fixing device is compensated by supplying power from the power storage device to the fixing device. Accordingly, stable and sufficient power can be supplied to the fixing roller of the fixing device regardless of the operation mode of the image forming apparatus, so that a decrease in fixing temperature in the fixing roller can be efficiently suppressed. Therefore, even with a fixing roller having a small heat capacity, the fixing performance of the output image can always be maintained well, and the fixing roller start-up time can be shortened, so that the standby fixing temperature and standby power are reduced. By doing so, heat dissipation loss is reduced and energy saving is achieved.
It should be noted that the power stored in the capacitor unit of the power storage device is appropriate after the start-up of the device main body is completed and when there is a margin that can be supplied to the power storage device with respect to the power upper limit of the commercial power source. It is supplied from the main power supply via the charging unit.

JP 2001-66926 A

  The conventional power storage device described above cannot supply power to the fixing device when the device fails and cannot be charged / discharged, and the original function of the power storage device cannot be achieved.

  For example, in a case where the image forming apparatus can be used even when the power storage device is out of order, the temperature rise time of the fixing device cannot be shortened or the power consumption in the fixing device cannot be reduced. Since fixing performance in the fixing device may not be maintained, it may be a user complaint. In contrast, when the image forming apparatus is configured so that it cannot be used in a state where the power storage device has failed, the user's image forming operation is suspended until an operator such as a service person performs maintenance of the power storage device. It is also conceivable.

The present invention has been made to solve the above problems, and it is possible to reliably grasp a failure of the power storage device is to provide a user-friendly image forming apparatus.

As a result of repeated researches to solve the above problems, the present inventor has come to know the following matters.
That is, the cause of failure of the power storage device includes disconnection / short circuit of an electric circuit in the device, liquid leakage from the capacitor unit, and the like. In such a case, even if a charging start signal is input from the control unit, a sufficient charging current does not flow to the capacitor unit, charging is not performed at all, charging energy is reduced, or charging voltage is rapidly increased. Or rise. Similarly, even when a discharge start signal is input from the control unit, a sufficient discharge current does not flow through the capacitor unit, so that no discharge is performed, the amount of discharge power decreases, or the discharge voltage decreases rapidly. To do.

  Specifically, when the power storage device is controlled by constant current charging or constant power charging, if the device breaks down, the charging start signal is input and charging is started within a certain time period even though the charging is started. The charging voltage of the capacitor unit does not increase to a predetermined value, the charging voltage does not increase at all, or the charging voltage increases rapidly. From another viewpoint, the charging current does not reach a constant value or the charging current does not flow at all even though the charging start signal is input and charging is started. Similarly, the discharge voltage of the capacitor does not drop to a predetermined value within a certain time, or the discharge voltage does not drop at all, even though the discharge start signal is input and the discharge is started. The voltage will drop rapidly. From another viewpoint, the discharge current does not reach a constant value or the discharge current does not flow at all even though the discharge start signal is input and the discharge is started.

In the image forming apparatus according to the first aspect of the present invention, a main power source and a heating member supplied with power from the main power source are installed, and a fixing member heated by the heating member is on a recording medium. An image forming apparatus comprising: a fixing device that heats a toner image to fix the toner image on the recording medium; and a chargeable / dischargeable power storage device that supplements power supplied from the main power source to the heating member. A failure detection unit that detects a failure of the power storage device; and a variable unit that varies the number of sheets conveyed per unit time in a plurality of recording media that are continuously conveyed to the fixing device. the conveying per the case of failure detection means detects the malfunction of said power storage device, the unit time when the temperature of the surface of the fixing member during the sheet passing is below the set value a predetermined It is intended to reduce the number.

The image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the variable means increases the number of transported sheets per unit time by increasing a transport interval in the plurality of recording media. It will be reduced.

The image forming apparatus according to a third aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein the variable means reduces the conveyance speed of the plurality of recording media per unit time. The number of transported sheets is reduced.

In the invention an image forming apparatus according to claim 4, wherein the invention comprises a main power source, together with the heating element powered from the main power supply is installed, the toner by heating the toner image on the recording medium An image forming apparatus comprising: a fixing device that fixes an image on the recording medium; and a chargeable / dischargeable power storage device that supplements power supplied from the main power source to the heating member, wherein the power storage device is faulty. Failure detecting means for detecting the temperature of the heating member, and variable means for changing the number of sheets conveyed per unit time in a plurality of recording media continuously conveyed to the fixing device, wherein the temperature of the heating member is variable. Control is made to reduce the number of transported sheets per unit time when the value is equal to or less than a predetermined set value, and the set value is increased when the failure detecting means detects a failure of the power storage device. Than is.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the failure detection unit starts supplying power from the power storage device to the heating member. It detects the failure before.

An image forming apparatus according to a sixth aspect of the present invention is the image forming apparatus according to any one of the first to fifth aspects, wherein the failure detecting means has a maximum electric energy that can be discharged in the capacitor portion of the power storage device. A failure of the power storage device is detected when the value falls below a predetermined value.

The image forming apparatus according to claim 7 is the image forming apparatus according to any one of claims 1 to 6 , wherein the failure detection unit detects a failure based on a voltage of a capacitor portion of the power storage device. To do.

The image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the seventh aspect , wherein the failure detecting means is a time when the capacitor section is charged or discharged, and the fluctuation of the voltage over a predetermined time. Is detected when the value is below a predetermined value or above a predetermined value.

An image forming apparatus according to a ninth aspect of the present invention is the image forming apparatus according to any one of the first to eighth aspects, wherein the failure detecting means detects a failure based on a current flowing in a capacitor portion of the power storage device. It is something to detect.

An image forming apparatus according to a tenth aspect of the present invention is the image forming apparatus according to the ninth aspect , wherein the failure detection unit is configured to charge or discharge the capacitor unit and the magnitude of the current is predetermined. A failure is detected when the value is less than or equal to the value.

An image forming apparatus according to an eleventh aspect of the present invention is the image forming apparatus according to any one of the first to tenth aspects, wherein the failure detecting means has a maximum electric energy that can be discharged in the capacitor portion of the power storage device. When the value is below a predetermined value, failure of the power storage device is detected in consideration of information related to the use environment.

The image forming apparatus according to a twelfth aspect of the present invention is the image forming apparatus according to any one of the first to eleventh aspects, wherein the failure detecting means has a maximum electric energy that can be discharged in the capacitor portion of the power storage device. The failure of the power storage device is detected when there are a plurality of times when the value falls below a predetermined value.

An image forming apparatus according to a thirteenth aspect of the present invention is the image forming apparatus according to any one of the first to twelfth aspects of the present invention , further comprising a display unit, wherein the display unit is configured such that the failure detection means When a failure is detected, a message indicating that the power storage device has failed is displayed.

In addition, in this application, "the voltage of a capacitor part" is the charge voltage or discharge voltage in a capacitor part. The “current flowing in the capacitor portion” is a charging current or a discharging current in the capacitor portion.
In addition, “charging power” is electrical energy stored in the power storage device during charging, and “discharge power” is electrical energy released from the power storage device during discharging. “Charge power amount (charge power amount)” is charge power × charge time, and “Discharge power amount (discharge power amount)” is discharge power × discharge time. Further, the “maximum power amount” that can be discharged is the maximum value of the discharge power amount.

According to the present invention, since the failure of the power storage device is detected by the failure detection means, it is possible to provide a user-friendly image forming apparatus that can grasp the state of the device .

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
A first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes an apparatus main body of a copying machine as an image forming apparatus, 2 an original reading unit that optically reads image information of an original D, and 3 an exposure light L based on image information read by the original reading unit 2. Are exposed to the photosensitive drum 5, 4 is an image forming unit that forms a toner image on the photosensitive drum 5, and 7 is a transfer unit that transfers an image formed on the photosensitive drum 5 to the recording medium P. Reference numeral 10 denotes a document transport unit (ADF) that transports a set document D to the document reading unit 2, reference numerals 12 to 14 denote a sheet feeding unit in which a recording medium P such as transfer paper is stored, and reference numeral 20 denotes an indeterminate state on the recording medium P. A fixing device for fixing a received image, 21 a fixing roller installed in the fixing device 20, 24 a pressure roller installed in the fixing device 20, and 40 a main power source for supplying power to a power-supplied member such as the fixing device 20 , 41 provides auxiliary power to the fixing device 20 (auxiliary power). It shows a power storage device to be.

With reference to FIG. 1, an operation during normal image formation in the image forming apparatus will be described.
First, the document D is conveyed from the document table in the direction of the arrow in the drawing by the conveyance roller of the document conveyance unit 10 and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads the image information of the document D passing above.
Then, the optical image information read by the document reading unit 2 is converted into an electric signal and then transmitted to the exposure unit 3 (writing unit). Then, exposure light L such as laser light based on the image information of the electrical signal is emitted from the exposure unit 3 toward the photosensitive drum 5 of the image forming unit 4.

On the other hand, in the image forming unit 4, the photosensitive drum 5 is rotated in the clockwise direction in the drawing, and image information is transferred onto the photosensitive drum 5 through a predetermined image forming process (charging process, exposure process, development process). A toner image corresponding to is formed.
Thereafter, the toner image formed on the photosensitive drum 5 is transferred by the transfer unit 7 onto the recording medium P conveyed by the registration roller.

On the other hand, the recording medium P conveyed to the transfer unit 7 operates as follows.
First, one of the plurality of paper feeding units 12, 13, and 14 of the image forming apparatus main body 1 is automatically or manually selected (for example, the uppermost paper feeding unit 12 is selected). To do.)
Then, the uppermost sheet of the recording medium P stored in the paper feeding unit 12 is transported toward the position of the transport path K.

  Thereafter, the recording medium P passes through the conveyance path K and reaches the position of the registration roller. Then, the recording medium P that has reached the position of the registration roller is conveyed toward the transfer unit 7 at the same timing in order to align with the toner image formed on the photosensitive drum 5.

After the transfer process, the recording medium P passes through the position of the transfer unit 7 and then reaches the fixing device 20 through the conveyance path. The recording medium P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 24, and the toner image is fixed by the heat received from the fixing roller 21 and the pressure received from both rollers 21, 24. Is done. The recording medium P on which the toner image is fixed is delivered from between the fixing roller 21 and the pressure roller 24 and then discharged from the image forming apparatus main body 1 as an output image.
Thus, a series of image forming processes is completed.

Next, the configuration / operation of the fixing device 20 installed in the image forming apparatus main body 1 will be described in detail with reference to FIG.
As shown in FIG. 2, the fixing device 20 mainly includes a fixing roller 21, a pressure roller 24, a thermistor 37, a separation claw 38, a guide plate 35, and the like.

  Here, the fixing roller 21 includes a thin cylindrical body that rotates in the direction of the arrow in FIG. 2 and two heaters 22 and 23 that serve as heating members fixed inside the cylindrical body. The cylindrical body of the fixing roller 21 has a fluororesin processed on the surface thereof to ensure releasability from the toner T. The heaters 22 and 23 of the fixing roller 21 are rod heaters having a heating wire inside, and both ends thereof are fixed to the side plate of the fixing device 20. Then, the cylindrical body is heated by the two heaters 22 and 23 supplied with power, and heat is applied to the toner T on the recording medium P from the surface of the cylindrical body.

One heater 22 is configured to be supplied with power from the main power supply 40 (power supply in the direction of arrow Y1 in the figure). The other heater 23 is configured to be appropriately supplied with power from the power storage device 41 (power supply in the direction of arrow Y2 in the figure). Details will be described later.
A thermistor 37 is in contact with the surface of the fixing roller 21, and the power supplied from the main power supply 40 and the power storage device 41 is adjusted based on the detection result of the roller surface temperature (fixing temperature) by the thermistor 37. It is.

  As shown in FIG. 2, a separation claw 38 that is swingably supported is disposed on the outer peripheral side of the fixing roller 21. The separation claw 38 has a tip abutting against the outer peripheral surface of the fixing roller 21, and the recording medium P sent from between the fixing roller 21 and the pressure roller 24 moves along the rotation of the fixing roller 21. The trouble which winds around 21 is suppressed.

  Further, the pressure roller 24 pressed against the fixing roller 21 by a pressure mechanism (not shown) mainly includes a cored bar and a plurality of elastic layers formed on the outer peripheral surface of the cored bar through an adhesive layer. . The elastic body layer of the pressure roller 24 has a layer thickness of 1 to 10 mm, and a material such as fluorine rubber, silicone rubber, or foamable silicone rubber is used. A thin release layer having a layer thickness of 300 μm or less is provided on the surface of the elastic layer. As a material for the release layer, polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), or the like can be used.

  Further, guide plates 35 for guiding the conveyance of the recording medium P are disposed on the entrance side and the exit side of the contact portion between the fixing roller 21 and the pressure roller 24, respectively. The guide plate 35 is fixed to the side plate of the fixing device 20.

The fixing device configured as described above operates as follows.
First, when the main power switch of the apparatus main body 1 is turned on, power is supplied from the main power supply of the apparatus main body 1 and the power storage device 41 to the heaters 22 and 23 of the fixing roller 21, respectively. Specifically, rated power is supplied to one heater 22 from a main power supply 40 connected to a commercial power supply outside the apparatus main body 1 via an outlet, and charging power stored in the power storage device 41 is discharged as discharge power. (It is the state of the solid line S in FIG. 6 described later).
As a result, the surface of the fixing roller 21 reaches a desired temperature (for example, 180 ° C.) in a short time, and the image formation by the apparatus main body 1 is possible.

  When the image forming apparatus is started up and the copy start button is pressed by the user, the fixing roller 21 and the pressure roller 24 are rotationally driven in the direction of the arrow in the drawing by a drive unit (not shown). Then, the recording medium P carrying the toner image T through the image forming process described above is fed between the fixing roller 21 and the pressure roller 24 while being guided by the guide plate 35 (in the direction of arrow Y10). Move.) The toner image T is fixed to the recording medium P by the heat received from the fixing roller 21 and the pressure received from both rollers 21 and 24, and the recording medium P is sent from between the fixing roller 21 and the pressure roller 24. (Movement in the direction of arrow Y11).

Further, even when the apparatus main body 1 consumes a large amount of power, the power storage device 41 supplies power to the heater 23.
Specifically, when the document reading unit 2 is performing a scanning operation, the power consumption is greater than when the document scanning unit 2 is not performing a scanning operation, and thus the power is supplied to the heater 23 by the power storage device 41. In addition, when the image is continuously formed (during continuous paper feeding), the heat of the fixing roller 21 is taken away by the recording medium P that is continuously conveyed, and thus the heater 23 by the power storage device 41 is supplied. Is fed. In addition, when the apparatus main body 1 is kept in a standby state for a long time and the energy saving mode functions and the fixing temperature is lowered, the power storage device 41 supplies power to the heater 23 when starting up from the standby state. It is carried out. In this way, the shortage of power supplied from the main power supply 40 to the fixing device 20 is compensated by the discharge power from the power storage device 41.

Note that when the fixing temperature of the fixing roller 21 is stable and almost saturated, power is hardly supplied from the power storage device 41 to the heater 23, and the main power supply 40 is intermittently supplied to the heater 22 with a small amount. Power supply. In addition, after the image forming operation is completed, power is not supplied from the main power supply 40 to the heater 22, so that there is a sufficient supply power. At this time, surplus power is supplied from the main power supply 40 to the power storage device 41 (power supply in the direction of arrow Y3 in FIG. 2), and power is stored in the power storage device 41 for the next discharge. .

  Further, in the image forming apparatus according to the first embodiment, a set value of a lower limit temperature (a fixing temperature at which fixing failure occurs) in which the fixing temperature detected by the thermistor 37 is set in advance during continuous paper feeding. In the following cases, control is performed so as to reduce the number of transported sheets (CPM) per unit time of the recording medium P that is continuously transported to the fixing device 20. Specifically, as a means (variable means) for reducing the CPM, the control unit does not reduce the conveyance speed of the recording medium P that is continuously conveyed (the rotation speed of the drive motor related to the conveyance drive is constant). By adjusting the conveyance timing of P, the sheet interval (conveyance interval) between the recording medium P and the recording medium P is increased. It is also possible to reduce the CPM in the recording medium P that is continuously conveyed by reducing the rotational speed of the drive motor related to the conveyance drive without increasing the space between the recording medium P and the recording medium P. As a result, the degree to which the heat on the surface of the fixing roller 21 is taken away by the recording medium P (heat loss amount per unit time) is reduced, so that the fixability of the output image at the time of continuous paper passing can be ensured.

Next, the configuration and operation of the power storage device 41 installed in the image forming apparatus main body 1 will be described in detail with reference to FIG.
As shown in FIG. 3, the power storage device 41 mainly includes a capacitor unit 42 (cell unit) to which power is charged / discharged, a charging unit 43 that charges the capacitor unit 42, and a switching unit 44 that switches charging / discharging of the capacitor unit 42. The voltmeter 50 or the like as voltage detecting means for detecting the voltage (the charge voltage and the discharge voltage) of the capacitor unit 42.

  Here, an electric double layer capacitor, a nickel-cadmium battery, or the like can be used as the capacitor portion 42 of the power storage device 41. The capacitor unit 42 supplies discharge power to the subordinate heater 23 in a state where the switching unit 44 is connected to the discharge circuit (the state shown in FIG. 3). The charging unit 43 rectifies the AC power supplied from the main power supply 40 and converts the DC power into DC with the switching unit 44 connected to the charging circuit, and supplies the charging power to the capacitor unit 42. The switching of the switching unit 44 is performed based on a switching signal (a charge start signal or a discharge start signal) transmitted via the CPU 48 based on a predetermined control program written in the memory of the control unit 45. That is, when the charging start signal is transmitted from the control unit 45 to the switching unit 44, the switching unit 44 is connected to the charging circuit, and when the discharging start signal is transmitted from the control unit 45 to the switching unit 44, the switching unit 44 is Connected to the discharge circuit. In addition, the discharge from the capacitor unit 42 to the heater 23 can be achieved not only by the configuration of the switching unit 44 of the first embodiment but also by a configuration in which switch control is performed using an FET or the like.

Further, the control unit 45 controls the discharge power within the circuit of the power storage device 41 to a predetermined power based on information detected by the thermistor 37. The power storage device 41 is charged with a constant current or a constant power. In other words, the power storage device 41 is controlled so that constant current charging or constant power charging is performed.
Further, information related to the voltage of the capacitor unit 42 is transmitted from the voltmeter 50 to the CPU 48 of the control unit 45, and information related to time is transmitted from the timer 49 serving as a time detecting means. The voltmeter 50 and the timer 49 serve as detection means for detecting fluctuations in the charge power amount and the discharge power amount, particularly when the maximum power amount that can be discharged in the capacitor unit 42 is equal to or less than a predetermined value. It functions as a failure detection means for detecting a failure. This will be described in detail later.

  On the other hand, the main power supply 40 is connected to the power storage device 41, the main heater 22, the main power supply switch 51, the control switch 47, a power supply body (not shown) other than the heater 22 in the apparatus main body 1, and the like. When the main power switch 51 is closed, power can be supplied to the main heater 22 and the power storage device 41 can be charged. Note that power supply to the heater 22 and charging of the power storage device 41 are performed based on a signal transmitted from the control unit 45 based on a predetermined control program written in the memory of the control unit 45, respectively. That is, when the switch 47 is closed, power is supplied to the heater 22. Further, when the switching unit 44 of the power storage device 41 is connected to the charging circuit, the power storage device 41 is charged.

Next, characteristic control in the first embodiment will be described with reference to FIGS. The first embodiment is configured so that a failure of the power storage device 41 can be detected.
FIG. 4 is a graph showing fluctuations in the charging voltage during charging when the power storage device 41 is not broken (normal time) and when it is broken (during failure). In FIG. 4, the horizontal axis indicates time, and the vertical axis indicates the charging voltage accumulated in the capacitor unit 42. Further, the solid line S indicates the charging voltage fluctuation at the normal time, and the one-dot chain line R1, the broken line R2, and the two-dot chain line R3 indicate the charging voltage fluctuation at the time of failure.

  As indicated by the solid line S in FIG. 4, in the power storage device 41 in the normal state, the charging of the capacitor unit 42 is started in accordance with the transmission of the above-described charging start signal (the time TS in the figure), and is constant. After the time has elapsed (the time TE in the figure), the charging voltage of the capacitor unit 42 reaches a predetermined value V1.

  On the other hand, as indicated by the alternate long and short dash line R1 and broken line R2, in the power storage device 41 at the time of failure, the charging voltage of the capacitor unit 42 is predetermined after a certain period of time even after the charging of the capacitor unit 42 is started. The value V1 is not reached. Furthermore, as indicated by a two-dot chain line R3, in the power storage device 41 at the time of failure, when charging of the capacitor unit 42 is started, the charging voltage of the capacitor unit 42 rapidly reaches the predetermined value V1 immediately after that.

  As a form of failure, as shown by a one-dot chain line R1, when the charging voltage does not rise at all from the initial value V0 even if the charging start signal is transmitted, the charging circuit is disconnected or short-circuited in the electric circuit in the power storage device 41. Is due to. Further, as shown by the broken line R2, when the charging voltage is only slightly increased from the initial value V0 even when the charging start signal is transmitted, the set charging power cannot be obtained due to the failure of the charging circuit in the power storage device 41. Is. Further, as indicated by a two-dot chain line R3, when the charging start signal is transmitted and the charging voltage suddenly increases from the initial value V0, the capacitance is extremely large due to liquid leakage of the capacitor unit 42 in the power storage device 41 or the like. It has become smaller.

  And the failure in such an electrical storage apparatus 41 is detected by the failure detection means 48-50. Specifically, the charging voltage accumulated in the capacitor unit 42 is detected by the voltmeter 50 within a certain time (detected by the timer 49) after the start of charging. When the charging voltage fluctuation becomes equal to or less than a predetermined value, the control unit 45 determines that the power storage device 41 has failed.

  On the other hand, FIG. 5 is a graph showing fluctuations in the discharge voltage during discharge depending on whether the power storage device 41 is normal or faulty. In FIG. 5, the horizontal axis indicates time, and the vertical axis indicates the discharge voltage in the capacitor unit 42. Further, the solid line S indicates the discharge voltage fluctuation at the normal time, and the one-dot chain line R1, the broken line R2, and the two-dot chain line R3 indicate the discharge voltage fluctuation at the time of failure.

  As indicated by the solid line S in FIG. 5, in the power storage device 41 at the normal time, the discharge of the capacitor unit 42 is started in accordance with the transmission of the above-described discharge start signal (the time TS in the figure). After the elapse of time (the time TE in the figure), the discharge voltage of the capacitor unit 42 reaches a predetermined value V0.

  On the other hand, as indicated by the alternate long and short dash line R1 and broken line R2, in the power storage device 41 at the time of failure, even if the discharge of the capacitor unit 42 is started, the discharge voltage of the capacitor unit 42 is predetermined after a certain time has elapsed. The value V0 is not reached. Further, as indicated by a two-dot chain line R3, in the power storage device 41 at the time of failure, when charging of the capacitor unit 42 is started, the charging voltage of the capacitor unit 42 rapidly reaches a predetermined value V0 immediately after that.

As a form of failure, as shown by a one-dot chain line R1, when the discharge voltage does not drop from the initial value V1 at all even when the discharge start signal is transmitted, the discharge circuit is disconnected or short-circuited in the electric circuit in the power storage device 41. Is due to. Further, as shown by the broken line R2, when the discharge voltage is slightly lowered from the initial value V1 even when the discharge start signal is transmitted, the set charging power cannot be obtained due to the failure of the charging circuit in the power storage device 41. Is. Further, as indicated by a two-dot chain line R3, when the discharge start signal is transmitted and the discharge voltage rapidly decreases from the initial value V1, the capacitance is extremely large due to liquid leakage of the capacitor unit 42 in the power storage device 41 or the like. It has become smaller.
Further, it is possible to detect that the discharge voltage does not decrease not only when the capacitor unit 42 itself fails but also when the heater 23 fed from the capacitor unit 42 is disconnected and the auxiliary power cannot be used. Therefore, it is determined as a failure of the power storage device 41. The disconnection of the heater 23 can also be determined based on detection of a temperature change.

  And the failure in such an electrical storage apparatus 41 is detected by the failure detection means 48-50 similarly to the time of charge. Specifically, the voltmeter 50 detects the discharge voltage remaining in the capacitor unit 42 within a certain time after the start of discharge. When the discharge voltage fluctuation becomes equal to or less than a predetermined value, the controller 45 determines that the power storage device 41 has failed.

  As described above, in the first embodiment, the failure of the power storage device 41 is detected relatively easily by detecting the voltage fluctuation during charging and discharging of the capacitor unit 42. Therefore, the failure of the power storage device 41 can be reliably grasped, and the response at the time of the failure can be performed smoothly.

The determination of the failure of the power storage device 41 by the control unit 45 is preferably performed when a detection result in which the voltage fluctuation of the capacitor unit 42 after the start of charging or after the start of discharging is not more than a predetermined value is repeated a plurality of times. Thereby, erroneous detection of a failure can be prevented in advance.
Moreover, it is preferable that the determination of the failure of the power storage device 41 by the control unit 45 is performed in consideration of information related to the usage environment of the power storage device 41. For example, when the power storage device 41 is used in a high temperature environment and the voltage fluctuation in a certain time is reduced, the detected voltage fluctuation is corrected to that in a normal temperature environment based on predetermined correction data. As a result, voltage fluctuations due to environmental fluctuations can be separated from those due to failures. Note that information on the usage environment can be collected by providing a temperature / humidity meter or the like in the apparatus main body 1 to detect temperature / humidity fluctuations.

Next, the operation of the image forming apparatus after the failure detection unit 48 to 50 detects a failure of the power storage device 41 will be described with reference to FIGS. 6 and 7.
FIG. 6 is a graph showing changes in the states of the fixing device 20, the power storage device 41, and the main power supply 40 when the image forming apparatus is started up.

FIG. 6A shows temporal changes in the fixing temperature on the surface of the fixing roller 21 detected by the thermistor 37. FIG. 6B shows temporal variation of the power supplied by the main power supply 40 and the power storage device 41 (the total power supplied to the two heaters 22 and 23). FIG. 6C shows temporal variation of the remaining power amount of the capacitor unit 42 in the power storage device 41.
In FIGS. 3A to 3C, a solid line S indicates each variation when the power storage device 41 is not detected as being in failure (normal time), and a broken line R indicates each variation when the power storage device 41 is detected as a failure. Show.

  First, when a failure of the power storage device 41 is detected by the failure detection means 48 to 50, control is performed so that charging / discharging by the failed power storage device 41 is not performed. Specifically, the switching unit 44 is controlled so as not to be connected to either the charging circuit or the discharging circuit. Thereby, it is possible to prevent occurrence of problems in other electric circuits of the apparatus body 1 due to continuing use of the failed power storage device 41.

Therefore, as shown in FIG. 6B, when the apparatus main body 1 is started up, the power supplied by the main power supply 40 and the power storage apparatus 41 when a failure of the power storage apparatus 41 is detected is only the power supplied by the main power supply 40. (The change from the state of the solid line S to the state of the broken line R). That is, as shown in FIG. 6C, when a failure of the power storage device 41 is detected, the power storage device 41 is not discharged (change from the state of the solid line S to the state of the broken line R).
Such a state is not limited at the time of start-up, and is also performed when the power consumption is large in the apparatus main body 1 as described above. That is, when a failure of the power storage device 41 is detected, any charge / discharge by the power storage device 41 is prohibited.

FIG. 7 is a graph showing control during continuous sheet passing of the image forming apparatus.
7A to 7C are graphs showing fixing temperature fluctuations when four sheets of the recording medium P are continuously passed. The horizontal axis indicates time, and the vertical axis indicates fixing detected by the thermistor 37. The fixing temperature on the surface of the roller 21 is shown. FIG. 7A shows the fixing temperature fluctuation at the normal time when the failure of the power storage device 41 is not detected, and FIGS. 7B and 7C are the fixing temperatures when the failure of the power storage device 41 is detected. Showing fluctuations.
Note that the fixing temperature H0 in FIG. 7 is the lower limit temperature (set value) of the fixing temperature described above.

  As shown in FIG. 7A, since the discharge power is supplied to the fixing roller 21 by the power storage device 41 at normal times, the CPM related to continuous paper feeding is set to a default value. That is, the conveyance speed of the recording medium P that is continuously passed through and the conveyance interval between the recording medium P and the recording medium P are set to default values.

Thus, first, the first recording medium that is continuously passed passes through the positions of the fixing roller 21 and the pressure roller 24 at time P1. At this time, the fixing temperature of the fixing roller 21 is lowered by a predetermined temperature from the temperature H1 due to the heat deprived by the recording medium. Then, at a time M0 corresponding to the conveyance interval, the fixing temperature of the fixing roller 21 recovers from the lowered temperature to the vicinity of the temperature H1. At this time, the fixing temperature is recovered in a relatively short time by the discharge power of the power storage device 41.
Similarly, for the second and subsequent recording media, the fixing temperature is lowered from the temperature H1 by a predetermined temperature at times P2, P3, and P4 (= P1) passing through the positions of the fixing roller 21 and the pressure roller 24. The fixing temperature of the fixing roller 21 is recovered to near the temperature H1 at a time M0 corresponding to the conveyance interval.

  On the other hand, as shown in FIG. 7B, at the time of failure detection, the supply of discharge power to the fixing roller 21 by the power storage device 41 is also prohibited in terms of control, and control for reducing CPM related to continuous paper feeding is performed. It is carried out. That is, the conveyance speed of the recording medium P that is continuously fed is normal, and is controlled so that the conveyance interval between the recording medium P and the recording medium P is increased.

Thus, first, the first recording medium that is continuously passed passes through the positions of the fixing roller 21 and the pressure roller 24 at time P1. At this time, the fixing temperature of the fixing roller 21 is decreased by a predetermined temperature from the temperature H1 in the same manner as in the normal state because the recording medium is deprived of heat. Then, at time M1 corresponding to the conveyance interval, the fixing temperature of the fixing roller 21 recovers from the lowered temperature to the vicinity of the temperature H1. At this time, since there is no supply of discharge power by the power storage device 41, the temperature is recovered over a longer time than usual (M1> M0).
Similarly, for the second and subsequent recording media, the fixing temperature is lowered from the temperature H1 by a predetermined temperature at times P2, P3, and P4 (= P1) passing through the positions of the fixing roller 21 and the pressure roller 24. Then, the fixing temperature of the fixing roller 21 is recovered to near the temperature H1 at a time M1 corresponding to the conveyance interval.

As described above, when a failure of the power storage device 41 is detected, the adjustment control is performed so that the space between the recording media during continuous paper passing is increased. After fixing one sheet of recording medium, it is possible to take a long time to recover the fixing temperature related to the fixing of the next recording medium.
Therefore, although the time for completing the continuous sheet passing is longer than that at the normal time, the productivity of image formation is lowered, or the temperature rise time at the rise is lowered as described with reference to FIG. It is possible to avoid the problem that the fixing property of the output image is lowered without noticing.

  FIG. 7C shows control different from that in FIG. 7B at the time of failure detection. In FIG. 7C, as in FIG. 7B, control is performed to reduce CPM related to continuous paper feeding. Here, control is performed so that the conveyance speed of the recording medium P that is continuously fed is reduced.

Accordingly, first, the first recording medium that is continuously passed passes through the positions of the fixing roller 21 and the pressure roller 24 in time P1 ′ (P1 ′> P1). At this time, the fixing temperature of the fixing roller 21 is lowered from the temperature H <b> 1 by a temperature fluctuation smaller than that at the normal time due to heat being taken away by the recording medium. Then, at time M2 corresponding to the conveyance interval, the fixing temperature of the fixing roller 21 recovers from the lowered temperature to the vicinity of the temperature H1. At this time, since there is no discharge power supply by the power storage device 41, the temperature is recovered with the same gradient as the temperature increase gradient at the conveyance interval M1 in FIG. 7B.
Similarly, for the second and subsequent recording media, the fixing temperature is changed from the temperature H1 to a predetermined temperature at times P2 ′, P3 ′, and P4 ′ (= P1 ′) passing through the positions of the fixing roller 21 and the pressure roller 24. Only drops. Then, the fixing temperature of the fixing roller 21 is recovered to near the temperature H1 at a time M2 corresponding to the conveyance interval.

As described above, when a failure of the power storage device 41 is detected, adjustment control is performed so that the conveyance speed of the recording medium at the time of continuous sheet passing is reduced, so that the heat loss per unit time of the fixing roller is reduced. Thus, the fixing temperature to be recovered after fixing one recording medium can be reduced without power supply from the power storage device 41.
Therefore, although the time for completing the continuous sheet passing is longer than that at the normal time, the productivity of image formation is reduced, and the temperature rise time at the start-up is reduced. It is possible to avoid a problem that the fixing property is lowered.

  In the above-described control at the time of continuous paper feeding, when the failure detection means 48 to 50 detect a failure of the power storage device 50, the set value of the lower limit temperature H0 of the fixing temperature can be changed to a higher value. In this case, in addition to the above-described CPM lowering control during continuous paper feeding, the threshold of the CPM lowering control when the fixing temperature described above becomes lower than the lower limit temperature H0 is increased. As a result, even when the power storage device 41 is out of order, it is possible to more reliably prevent a reduction in the fixability of the output image during continuous paper feeding.

As described above, according to the first embodiment, the failure detectors 48 to 50 detect voltage fluctuations during charging / discharging in the capacitor unit 42, so that the failure of the power storage device 41 can be reliably grasped. It is possible to respond smoothly at the time of failure. Furthermore, since charging / discharging of the power storage device 41 after the failure detection is prohibited in terms of control, it is possible to suppress other problems caused by the failure of the power storage device 41.
In addition, when the power storage device 41 breaks down, the use of the image forming apparatus main body 1 is not completely stopped, and certain restrictions are imposed such as an increase in temperature rise time during startup and a decrease in CPM during continuous paper feeding. It is controlled so that it can be used. Thereby, even if the power storage device 41 is out of order, the user's image forming operation is not interrupted, and the usability for the user is improved.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 8 is a circuit diagram showing the power storage device in the second embodiment, which corresponds to FIG. 3 in the first embodiment. In the present second embodiment, the failure of the power storage device 41 is detected based on the current flowing through the capacitor unit 42. The failure of the power storage device 41 is detected based on the charging voltage and the discharge voltage of the capacitor unit 42. This is different from the first embodiment.

  As shown in FIG. 8, the power storage device 41 of the second embodiment detects currents (charging current and discharging current) flowing in the capacitor unit 42 instead of the voltmeter 50 in the first embodiment. An ammeter 60 is installed as current detecting means. Detection results relating to the charging current and discharging current detected by the ammeter 60 are transmitted to the CPU 48 of the control unit 45. Then, in control unit 45, failure of power storage device 41 is determined based on the detection result of ammeter 60.

  FIG. 9 is a graph showing fluctuations in the charging current and discharging current during charging / discharging in the power storage device 41 depending on whether it is normal or failure. In FIG. 9, the horizontal axis represents time, and the vertical axis represents the charging current or discharging current flowing through the capacitor unit 42. Further, the solid line S indicates the charging current fluctuation or the discharging current fluctuation at the normal time, and the broken line R1 and the alternate long and short dash line R2 indicate the charging current fluctuation or the discharging current fluctuation at the time of failure.

As shown by the solid line S in FIG. 9, in the normal power storage device 41, the charging or discharging of the capacitor unit 42 is started in accordance with the transmission of the charge start signal or the discharge start signal (time TS in the figure). Until the charging or discharging ends (time TE in the figure), the charging current or discharging current of the capacitor unit 42 reaches the predetermined value I ₁ . Note that, since the power storage device 41 is controlled by constant current charging and constant current discharging, the predetermined value I ₁ is constant with no temporal variation.

On the other hand, as shown by the broken line R1 and the alternate long and short dash line R2, in the power storage device 41 at the time of failure, even if charging or discharging of the capacitor unit 42 is started, the charging current or discharging current of the capacitor unit 42 is a predetermined value. I ₁ is not reached.
As a failure mode, as shown by a broken line R1, when the charge current or discharge current does not increase from the initial value 0 even when the charge start signal or discharge start signal is transmitted, the charge in the electric circuit in the power storage device 41 is charged. This is due to disconnection or short circuit of the circuit or discharge circuit. Further, as shown by a one-dot chain line R2, when the charge current or the discharge current is only slightly increased from the initial value 0 even when the charge start signal or the discharge start signal is transmitted, the liquid leakage of the capacitor unit 42 in the power storage device 41 occurs. Etc.

Such a failure in the power storage device 41 is detected by the failure detection means 48 and 60. Specifically, the charging current or discharging current flowing through the capacitor unit 42 is detected by the ammeter 60 after starting charging or after starting discharging. And when the magnitude | size of the detected charging current or discharging current is below a predetermined value, it is judged by the control part 45 that the electrical storage apparatus 41 failed.
Further, when a failure of the power storage device 41 is detected, control is performed to prohibit charging / discharging by the power storage device 41. Then, at the time of continuous paper feeding, as in the first embodiment, control is performed so as to reduce the CPM related to continuous paper feeding.

As described above, according to the second embodiment, since the current value at the time of charging / discharging in the capacitor unit 42 is detected by the failure detection means 48, 60, the failure of the power storage device 41 can be reliably grasped. It is possible to respond smoothly at the time of failure. Furthermore, since charging / discharging of the power storage device 41 after the failure detection is prohibited in terms of control, it is possible to suppress other problems caused by the failure of the power storage device 41.
In addition, when the power storage device 41 breaks down, the use of the image forming apparatus main body 1 is not completely stopped, and certain restrictions are imposed such as an increase in temperature rise time during startup and a decrease in CPM during continuous paper feeding. It is controlled so that it can be used. Thereby, even if the power storage device 41 is out of order, the user's image forming operation is not interrupted, and the usability for the user is improved.

  In each of the above embodiments, it is preferable to perform control so that, when a failure of the power storage device 41 is detected, a message to that effect is displayed on the display unit (not shown) of the device body 1. Accordingly, the user can accurately know the state of the image forming apparatus and can quickly report to an operator such as a serviceman.

  In each of the above embodiments, the power storage device 41 is used as an auxiliary power supply device when the image forming apparatus is started up or when power consumption is excessive. However, application of the present invention is not limited to this, and the present invention can be applied to all power storage devices that supply power to a power-supplied body. Also in that case, a power storage device that is easy to use can be provided as in the above embodiments.

Embodiment 3 FIG.
A third embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 10 is a block diagram illustrating a fixing device according to the third embodiment. The third embodiment is different from the first embodiment in that an abnormality of the fixing device is detected based on the failure detection information detected by the failure detection means.

  As shown in FIG. 10, the power storage device 41 is provided with a failure detection unit 53, a storage unit 54, a time detection unit 49, a temperature detection unit 37, an abnormality detection unit 55, and the like. The failure detection unit 53 is the failure detection unit 48 to 50 described in the first embodiment, and detects a failure of the capacitor unit 42 and the like and outputs the information (failure detection information) to the storage unit 54.

  The time detection means 49 is the timer described in the first embodiment, and detects the power supply time by the power storage device 41. Information (detection time information) detected by the time detection unit 49 is output to the storage unit 54. Here, the power supply time by the power storage device 41 is, for example, a measurement of an accumulated time during which power supply is performed using an ON signal of the main power switch as a start signal. Further, the time detection unit 49 outputs a signal for instructing the timing of detecting the temperature of the fixing roller 21 to the temperature detection unit 37.

  The temperature detection unit 37 is the thermistor described in the first embodiment, and detects the surface temperature (fixing temperature) of the fixing roller 21. Information (detected temperature information) detected by the temperature detection unit 37 is output to the abnormality detection unit 55.

  The storage means 54 holds a plurality of pieces of relationship information (referring to the solid lines Q1 and Q2 shown in FIG. 11) indicating the correspondence between the power supply time and the temperature of the heating member. Then, based on the failure detection information output from the failure detection means 53, one relation information is selected from the plurality of relation information held in the storage means 54. Then, the reference temperature of the fixing roller 21 is calculated based on the selected one related information and the detected time information output from the time detecting unit 49. As described above, the storage unit 54 functions as a part of the temperature calculation unit for calculating the reference temperature of the fixing roller 21.

  FIG. 11 is a graph showing a plurality of relation information held in the storage unit 54. In FIG. 11, the horizontal axis indicates the power supply time when power supply from the main power supply 40 (external power supply) to the heater 22 and power supply from the capacitor unit 42 to the heater 23 are performed simultaneously. The vertical axis indicates the fixing temperature of the fixing roller 21. That is, FIG. 11 is a graph showing the temperature rise characteristics of the fixing roller 21.

In FIG. 11, a solid line Q <b> 1 indicates a temperature rise characteristic when a failure occurs in the power storage device 41, and a solid line Q <b> 2 indicates a temperature rise characteristic when no failure occurs in the power storage device 41. In FIG. 11, the temperature rise characteristic when no failure has occurred in the power storage device 41 is shown by only the solid line Q <b> 2, but actually, a plurality of temperature rise characteristics corresponding to the size of the remaining capacity of the capacitor unit 42 are shown. Is held.
As the remaining capacity of the capacitor unit 42 decreases, the gradient of the temperature rise characteristic decreases, and when the power storage device 41 fails, the gradient of the temperature rise characteristic is minimized (in the state of the solid line Q1). Such relation information (temperature rise characteristics) is reproducible information.

  The storage unit 54 can output temperature information corresponding to the input time information by holding the relationship information as shown in FIG. 11 as tabular data. As another aspect, by storing in advance a relational expression between the power supply time and the fixing temperature in the storage unit 54, the time information can be substituted into the relational expression and the temperature information can be output.

The abnormality detection unit 55 compares the reference temperature information output from the storage unit 54 (temperature calculation unit) with the actual fixing temperature (detected temperature information) detected by the temperature detection unit 37, and the comparison result. Based on this, an abnormality of the fixing device 20 is detected.
Specifically, if the difference between the detected temperature information and the reference temperature information is within a predetermined range, it is determined that the fixing device 20 is normal. On the other hand, if the difference between the detected temperature information and the reference temperature information is out of the predetermined range, it is determined that there is an abnormality in the fixing device 20. When an abnormality of the fixing device 20 is detected by the abnormality detection unit 55, it is preferable to output a signal from the abnormality detection unit 55 and notify that there is an abnormality by an alarm signal, a screen display, or the like.

Hereinafter, a series of operations until abnormality detection is performed will be described with reference to FIG.
First, when the main power switch is turned on, heating of the fixing roller 21 is started as power is supplied to the heaters 22 and 23. At this time, the time detector 49 starts measuring time.

  When the failure detection unit 53 detects a failure of the power storage device 41 by the procedure described in the first embodiment, the information (failure detection information) is transmitted to the storage unit 54. In the storage means 54, one piece of related information (indicated by a solid line Q1 in FIG. 11) is selected from a plurality of pieces of related information (temperature rise characteristics) in accordance with the input of the failure detection information. On the other hand, the time detection means 49 transmits detection time information T1 when a failure is detected to the storage means 54.

In the storage means 54, the reference temperature H1 is calculated from the detection time information T1 from the time detection means 49 and the selected relation information Q1. This reference temperature information H1 is transmitted to the abnormality detection means 55. On the other hand, from the temperature detection unit 37, actually detected temperature information H <b> 2 when a failure is detected is transmitted to the abnormality detection unit 55.
Then, the abnormality detection means 55 compares the reference temperature information H1 from the storage means 54 and the detected temperature information H2 from the temperature detection means 37, and if the difference is equal to or greater than a predetermined value, the abnormality of the entire fixing device 20 is detected. (It is distinguished from the failure of the power storage device 41).

  As described above, according to the third embodiment, the failure detection unit 53 can reliably grasp the failure of the power storage device 41 and can smoothly cope with the failure. Further, since the abnormality of the entire fixing device 20 can be detected after the failure is detected, the state of the fixing device 20 can be reliably grasped.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 12 is a block diagram illustrating the fixing device according to the fourth embodiment, and corresponds to FIG. 10 according to the third embodiment. In the fourth embodiment, the abnormality of the fixing device 20 is detected by comparing the reference time information and the detection time information. The abnormality of the fixing device 20 is compared by comparing the reference temperature information and the detected temperature information. This is different from the detected third embodiment.

The time detection means 49 detects the power supply time by the power storage device 41. Information (detection time information) detected by the time detection means 49 is output to the abnormality detection means 55. Here, the power supply time by the power storage device 41 is, for example, a measurement of an accumulated time during which power supply is performed using an ON signal of the main power switch as a start signal. The accumulated time is measured until a signal is received from the temperature detection unit 37, and the detection time information is transmitted to the abnormality detection unit 55.
The temperature detector 37 detects the surface temperature (fixing temperature) of the fixing roller 21. Information (detected temperature information) detected by the temperature detection unit 37 is output to the storage unit 54.

  Similar to the third embodiment, the storage unit 54 stores a plurality of relational information (temperature increase characteristic data) indicating correspondence between the power supply time and the temperature of the heating member. Based on the failure detection information output from the failure detection means 53, one relation information (indicated by the solid line Q1 in FIG. 11) is selected from the plurality of relation information held in the storage means 54. Then, based on the selected one related information and the detected temperature information output from the temperature detecting means 37, the reference time of the fixing roller 21 is calculated. As described above, the storage unit 54 functions as a part of the time calculation unit for calculating the reference time of the fixing roller 21.

  The storage unit 54 can output time information corresponding to the input temperature information by holding the relationship information as shown in FIG. 11 as tabular data. As another aspect, by storing in advance a relational expression between the power supply time and the fixing temperature in the storage unit 54, the time information can be output by substituting the temperature information into the relational expression.

The abnormality detection unit 55 compares the reference time information output from the storage unit 54 (time calculation unit) with the actual power supply time detected by the time detection unit 49, and fixes based on the comparison result. An abnormality of the device 20 is detected.
Specifically, if the difference between the detection time information and the reference time information is within a predetermined range, it is determined that the fixing device 20 is normal. On the other hand, when the difference between the detection time information and the reference time information is out of the predetermined range, it is determined that there is an abnormality in the fixing device 20.

Hereinafter, a series of operations until abnormality detection is performed will be described.
First, when the main power switch is turned on, heating of the fixing roller 21 is started as power is supplied to the heaters 22 and 23. At this time, the time detector 49 starts measuring time.

  When the failure detection unit 53 detects a failure of the power storage device 41, the information (failure detection information) is transmitted to the storage unit 54. In the storage means 54, one piece of related information (indicated by a solid line Q1 in FIG. 11) is selected from a plurality of pieces of related information (temperature rise characteristics) in accordance with the input of the failure detection information. On the other hand, the temperature detection means 37 transmits detected temperature information H1 when a failure is detected to the storage means 54.

In the storage means 54, the reference time T1 is calculated from the detected temperature information H1 from the temperature detecting means 37 and the selected relation information Q1. This reference time information T1 is transmitted to the abnormality detection means 55. On the other hand, the actual detection time information T2 when the failure is detected is transmitted from the time detection means 49 to the abnormality detection means 55.
Then, the abnormality detection means 55 compares the reference time information T1 from the storage means 54 and the detection time information T2 from the time detection means 49, and if the difference is equal to or greater than a predetermined value, the abnormality of the entire fixing device 20 is detected. (It is distinguished from the failure of the power storage device 41).

  As described above, according to the fourth embodiment, the failure detection unit 53 can reliably grasp the failure of the power storage device 41 and can smoothly cope with the failure. Further, as in the third embodiment, since the abnormality of the entire fixing device 20 can be detected after the failure is detected, the state of the fixing device 20 can be reliably grasped.

Embodiment 5 FIG.
A fifth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 13 is a flowchart illustrating control performed by the fixing device according to the fifth embodiment. The fifth embodiment is different from the first embodiment in that the failure detection of the power storage device 41 is performed before the power supply (discharge) from the capacitor unit 42 to the heater 23 of the fixing roller 21 is started. Is different.

As shown in FIG. 13, first, when the main power switch is turned on (step S1), it is determined whether the detected temperature detected by the thermistor 37 (temperature detecting means) is lower than the set temperature (step S2). . As a result, when it is determined that the detected temperature is not lower than the set temperature, the flow after step S2 is repeated.
On the other hand, when it is determined that the detected temperature is lower than the set temperature, the failure detection information is acquired by the failure detection means 53 (48 to 50) (step S3). Then, it is determined whether or not a failure has occurred in power storage device 41 (step S4).

As a result, when it is determined that no failure has occurred in the power storage device 41, the SC table value for failure is referred to (the solid line Q2 stored in the storage means 54 described in the third embodiment). Etc.). Furthermore, conditions for discharging from the power storage device 41 are set (step S5).
Thereafter, discharging (power supply) from the power storage device 41 is started based on the conditions set in step S5.

On the other hand, when it is determined in step S4 that a failure has occurred in the power storage device 41, the SC table value for failure is referred to (the storage unit 54 described in the third embodiment). The relationship information of the solid line Q1 stored in the Furthermore, conditions for discharging from the power storage device 41 are set (step S7).
Thereafter, based on the conditions set in step S7, discharge from the power storage device 41 is started as necessary. Actually, in most cases, the discharge from the capacitor unit 42 is stopped, and when the abnormality detection unit 55 of the third embodiment does not detect the abnormality of the fixing device 20, it will be described in the first embodiment. In the state where the above restrictions are imposed, power is supplied to the fixing device 20 (by the main power supply 40).

  As described above, according to the fifth embodiment, before the power supply from the power storage device 41 is started, the failure detection unit 53 can reliably grasp the failure of the power storage device 41 and The time can be handled smoothly.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the above-described embodiments can be modified as appropriate in addition to those suggested in the above-described embodiments. Is clear. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiments, and the number, position, shape, and the like that are suitable for implementing the present invention can be used.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view showing a fixing device installed in the image forming apparatus of FIG. 1. FIG. 2 is a circuit diagram showing a power storage device installed in the image forming apparatus of FIG. 1. It is a graph which shows the state at the time of charge when the electrical storage apparatus of FIG. 3 fails. It is a graph which shows the state at the time of discharge when the electrical storage apparatus of FIG. 3 fails. 4 is a graph showing a state when the image forming apparatus is started up when the power storage device in FIG. 3 fails. FIG. 4 is a graph showing control during continuous sheet passing of the image forming apparatus when the power storage device of FIG. 3 fails. It is a circuit diagram which shows the electrical storage apparatus in Embodiment 2 of this invention. It is a graph which shows the state at the time of charge and discharge when the electrical storage apparatus of FIG. 8 fails. It is a block diagram which shows the fixing device in Embodiment 3 of this invention. 6 is a graph showing relationship information between power supply time and fixing temperature. It is a block diagram which shows the fixing device in Embodiment 4 of this invention. It is a flowchart which shows the control performed with the fixing device in Embodiment 5 of this invention.

Explanation of symbols

1 image forming apparatus body (apparatus body),
2 Document reading section, 3 Exposure section, 4 Image forming section, 7 Transfer section,
10 Document transport section, 12-14 Paper feed section, 20 Fixing device,
21 fixing roller (fixing member), 22 heater (heating member),
24 pressure roller, 37 thermistor (temperature detection means),
40 Main power supply (external power supply),
41 power storage device, 42 capacitor unit, 43 charging unit, 44 switching unit,
45 control unit, 47 switch, 48 CPU,
49 Timer (time detection means), 50 Voltmeter (voltage detection means),
51 main power switch, 53 failure detection means, 54 storage means,
55 abnormality detection means, 60 ammeter (current detection means), P recording medium.

Claims (13)

A main power supply,
A fixing device in which a heating member supplied with power from the main power supply is installed, and a fixing member heated by the heating member heats a toner image on a recording medium and fixes the toner image on the recording medium; ,
A chargeable / dischargeable power storage device that supplements the power supplied from the main power source to the heating member;
An image forming apparatus comprising:
Failure detection means for detecting a failure of the power storage device;
Variable means for varying the number of conveyed sheets per unit time in a plurality of recording media continuously conveyed to the fixing device;
With
When the failure detecting unit detects a failure of the power storage device, the variable unit is configured to convey the unit per unit time when the surface temperature of the fixing member at the time of passing a sheet is equal to or lower than a predetermined set value. An image forming apparatus characterized in that the number of sheets is reduced.   The image forming apparatus according to claim 1, wherein the variable unit increases a conveyance interval in the plurality of recording media to reduce the number of conveyances per unit time.   3. The image forming apparatus according to claim 1, wherein the variable unit decreases a conveyance speed in the plurality of recording media to reduce the number of conveyances per unit time. 4. A main power supply,
A heating device that is powered by the main power supply, and a fixing device that heats the toner image on the recording medium and fixes the toner image on the recording medium;
A chargeable / dischargeable power storage device that supplements the power supplied from the main power source to the heating member;
An image forming apparatus comprising:
Failure detection means for detecting a failure of the power storage device;
Variable means for varying the number of conveyed sheets per unit time in a plurality of recording media continuously conveyed to the fixing device;
With
The variable means is controlled to reduce the number of transported sheets per unit time when the temperature of the heating member is equal to or lower than a predetermined set value.
The image forming apparatus, wherein when the failure detection unit detects a failure of the power storage device, the set value is changed to a higher value.   The image forming apparatus according to claim 1, wherein the failure detection unit detects a failure before starting to supply power from the power storage device to the heating member.   The failure detection unit detects a failure of the power storage device when a maximum dischargeable power amount in the capacitor unit of the power storage device becomes a predetermined value or less. The image forming apparatus according to any one of the above.   The image forming apparatus according to claim 1, wherein the failure detection unit detects a failure based on a voltage of a capacitor unit of the power storage device.   The failure detection means detects a failure when charging or discharging of the capacitor unit is performed and the fluctuation of the voltage over a predetermined time is a predetermined value or less or a predetermined value or more. 8. The image forming apparatus according to 7.   The image forming apparatus according to claim 1, wherein the failure detection unit detects a failure based on a current flowing in a capacitor unit of the power storage device.   The image formation according to claim 9, wherein the failure detection unit detects a failure when the capacitor unit is charged or discharged and the magnitude of the current is a predetermined value or less. apparatus.   The failure detection means detects a failure of the power storage device by referring to information on a use environment when the maximum amount of electric power that can be discharged in the capacitor unit of the power storage device becomes a predetermined value or less. The image forming apparatus according to claim 1.   2. The failure detection unit detects a failure of the power storage device when a maximum amount of electric power that can be discharged in a capacitor unit of the power storage device is equal to or less than a predetermined value a plurality of times. The image forming apparatus according to claim 11. With a display,
The said display part displays that the said electrical storage apparatus failed, when the said failure detection means detects the failure of the said electrical storage apparatus, The Claim 1 characterized by the above-mentioned. Image forming apparatus.

Images