JP4745022B2 - Auxiliary power supply apparatus for image forming apparatus and fixing apparatus - Google Patents

Description

  The present invention forms a toner image on an image carrier, transfers the toner image to a long recording medium longer than a standard size, and records the toner image transferred to the long recording medium with a fixing device. The present invention relates to an image forming apparatus for fixing to a medium and an auxiliary power supply device for the fixing device.

  According to the above-described image forming apparatus configured as an electronic copying machine, a printer, a facsimile machine, or a multifunction machine thereof, an image can be formed on a long recording medium having a length of, for example, 10 m to 15 m. is there. A fixing device used in such an image forming apparatus has a fixing member, a pressure member pressed against the fixing member, a temperature detecting means for detecting the temperature of the fixing member, and a heating means for heating the fixing member. A long recording medium carrying a toner image is passed through the nip portion between the fixing member and the pressure member, and heat and pressure are applied to the toner of the toner image on the long recording medium during the passage. The toner image is fixed on a long recording medium. When a long recording medium is passed between the fixing member and the pressure member of such a fixing device, the heat of the fixing member continues to be taken away by the long recording medium for a long time. While the long recording medium passes through the fixing member, the temperature of the fixing member becomes lower than the temperature suitable for fixing the toner image, which may cause a fixing failure of the toner image. Therefore, when a fixing member having a large heat capacity is used and the long recording medium passes between the fixing member and the pressure member, the temperature of the fixing member is lower than the temperature suitable for fixing the toner image. It is necessary to prevent. However, when such a large-capacity fixing member is used, it is inevitable that the start-up time until the fixing member rises to a temperature suitable for fixing the toner image becomes long during the start-up operation of the fixing device.

  A general configuration of a fixing device used in an image forming apparatus is described in, for example, Patent Documents 1 to 4.

JP 2002-184554 A JP 2005-39873 A JP 2005-32558 A JP 2005-18049 A

  The object of the present invention is to solve the problem that the temperature of the fixing member is lower than the temperature suitable for fixing the toner image during the fixing operation of the toner image on the long recording medium without using a fixing member having a particularly large heat capacity. It is an object of the present invention to provide an image forming apparatus and an auxiliary power supply device for a fixing device.

  In order to achieve the above object, the present invention forms a toner image on an image carrier, transfers the toner image to a long recording medium longer than a standard size, and transfers the toner image to the long recording medium. The image forming apparatus fixes the image to a long recording medium using a fixing device, the fixing device including a fixing member, a pressure member pressed against the fixing member, and a temperature detecting unit that detects a temperature of the fixing member. And a heating means for heating the fixing member, and a long recording medium carrying a toner image is passed through a nip portion between the fixing member and the pressure member, and heat and pressure are applied to the toner of the toner image at the time of passing. In the image forming apparatus for fixing the toner image to the long recording medium, the heating means includes a main heating member supplied with power from a main power source, and a plurality of auxiliary units that can be switched between series connection and parallel connection. Auxiliary heating powered by power supply And a calculating means for calculating a slope of a change in temperature of the fixing member detected by the temperature detecting means, and the fixing member only by the main heating member supplied with power from the main power source. When the toner image is fixed by passing a long recording medium between the fixing member and the pressure member while heating the fixing member, the temperature of the fixing member detected by the temperature detecting means is When the absolute value of the inclination of the temperature change of the fixing member is equal to or higher than a predetermined inclination threshold when the temperature required for fixing cannot be maintained, the temperature becomes lower than a predetermined fixing temperature threshold. Are connected in series, power is supplied to the auxiliary heating member from the plurality of auxiliary power supplies, and when the absolute value of the temperature change inclination of the fixing member is smaller than the inclination threshold, the plurality of power supplies are connected in parallel. Connection Te proposes an image forming apparatus characterized by comprising an auxiliary power supply output control means for supplying power to the auxiliary heating member from the plurality of auxiliary power (claim 1).

  The image forming apparatus according to claim 1, wherein the auxiliary power source is configured by a chargeable / dischargeable electric double layer capacitor, and the electric power is not supplied from the main power source to the main heating member. It is advantageous if the double layer capacitor is configured to be charged (claim 2).

  Further, in the image forming apparatus according to claim 1, it is advantageous that the auxiliary power source is constituted by a fuel cell that can be used repeatedly after changing fuel (claim 3).

  Further, in the image forming apparatus according to claim 3, the fuel cell includes a unit for detecting a remaining amount of fuel, a unit for displaying the remaining amount of fuel, and replacement of fuel when the remaining amount of fuel falls below a certain value. It is advantageous to have means for prompting (claim 4).

  In order to achieve the above object, the present invention provides a plurality of auxiliary power supplies that can be switched between series connection and parallel connection, and the fixing member when the temperature of the fixing member is equal to or lower than a predetermined fixing temperature threshold. When the absolute value of the temperature change gradient is equal to or greater than a predetermined gradient threshold value, the plurality of auxiliary power supplies are connected in series to supply power from the plurality of auxiliary power supplies to the auxiliary heating member for heating the fixing member, When the absolute value of the inclination of the temperature change of the fixing member is smaller than the inclination threshold, the plurality of power sources are connected in parallel, and power is supplied from the plurality of auxiliary power sources to the auxiliary heating member for heating the fixing member. An auxiliary power supply device for a fixing device comprising an auxiliary power supply output control means is proposed.

  According to the present invention, it is possible to prevent or effectively suppress a problem that the temperature of the fixing member is lower than the temperature suitable for fixing during the fixing operation of the toner image on the long recording medium.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  The image forming apparatus shown in FIG. 1 includes a paper feeding unit 1, an image forming unit 2 disposed on the paper feeding unit 1, and an image reading unit 3 disposed on the image forming unit 2. have. A document (not shown) placed on the document table 4 of the image reading unit 3 is aligned in the width direction by a side fence (not shown) and then fed in the direction of arrow A by the paper feed roller 5. , And passes under the contact type reading device 6. A document width detection sensor and a document length detection sensor (not shown) are provided on the document table 4, and the document size is detected by these sensors. The contact-type reading device 6 has a rod lens array and an image sensor not shown in the drawing. When a document passes under the contact-type reading device 6, an LED array, a fluorescent lamp, or the like is placed on the document. The light from the light source is irradiated, the reflected light passes through the rod lens and reaches the image sensor, and a document image is formed on the image sensor and subjected to photoelectric conversion. The document whose image has been read is discharged to the discharge tray 7 or 8 as indicated by an arrow B or C. In addition, the image reading unit 3 is provided with an operation unit (not shown) for inputting a print operation start instruction, information such as the number of repeat copies and the length of a sheet.

  The image forming unit 2 includes a drum-shaped photoconductor 9 which is an example of an image carrier. The photoconductor 9 is driven to rotate counterclockwise in FIG. 1, and at this time, the photoconductor 9 is charged by a charging device 10. Is done. On the other hand, the image signal read by the contact-type reading device 6 is subjected to image processing, light corresponding to the image signal is emitted from the exposure device 11 provided with the LED array, and the light is irradiated on the charged photoreceptor surface. . As a result, an electrostatic latent image is formed on the photoconductor 9, and the latent image is visualized as a toner image by the developing device 12.

  On the other hand, the paper feed unit 1 has two upper and lower roll paper trays 13 and 14, and the roll paper trays 13 and 14 each have roll paper 15, 16, 17 and 18 wound around a paper tube. Are rotatably supported, and paper feed rollers 19, 20, 21, and 22 are arranged corresponding to the respective roll papers. Each of the roll paper trays 13 and 14 can be pulled out to the left in FIG. 1 from the apparatus housing, and roll paper can be set or jammed with the roll paper tray being pulled out. Paper is fed out from any selected roll paper 15, 16, 17 or 18 by the corresponding paper feed roller 19, 20, 21 or 22, and the paper is fed into the image forming unit 2. The paper is cut into a predetermined length by the cutter unit 23 or 24. The sheet is fed to the photoconductor 9 at a predetermined timing by the registration roller pair 25. At this time, the toner image formed on the photoconductor 9 is transferred to the paper by the action of the transfer device 26. Next, the sheet is separated from the photosensitive member 9 by the action of the separating device 27, and subsequently conveyed to the fixing device 29 by the conveying belt 28. The transfer residual toner adhering to the surface of the photoreceptor 9 after the toner image is transferred is removed by the cleaning device 50. When the paper passes through the fixing device 29, the transferred toner image is fixed on the paper. The paper that has passed through the fixing device 29 is discharged by a paper discharge roller 30 or 31 to a paper discharge unit 32 constituted by the upper surface of the image forming unit 2 or a paper discharge unit 33 disposed behind the image forming unit 2. The

  The image forming apparatus shown in FIG. 1 forms an image on the paper that is fed out from the roll papers 15 to 18 and cut, so that the length of the paper can be selected substantially freely. Therefore, the length of the paper can be made longer than the length of the standard size, and the length can be as long as, for example, 15 m. A recording medium other than paper can be used as the long recording medium. In the following description, a long recording medium made of paper that has been fed from roll paper and cut by the cutter unit 23 or 24, or already cut is referred to as a long recording medium P (see FIG. 2). To.

  In the image forming apparatus shown in FIG. 1, a toner image is formed on an image carrier made of a photoreceptor 9, and the toner image is transferred to a long recording medium longer than a standard size. The toner image transferred to the toner image is fixed on the long recording medium by the fixing device 29. The toner image on the photosensitive member is primarily transferred to the intermediate transfer member, and the toner image on the intermediate transfer member is transferred to the intermediate transfer member. It can also be configured to perform secondary transfer onto a long recording medium. In this case, the intermediate transfer member constitutes an image carrier, and the toner image formed on the image carrier is transferred to a long recording medium.

  FIG. 2 is an enlarged sectional view of the fixing device 29 shown in FIG. The fixing device 29 shown here detects a fixing roller 36 as an example of a fixing member, a pressure roller 37 as an example of a pressure member in pressure contact with the fixing roller 36, and the surface temperature of the fixing roller 36. A temperature detecting unit 38 and a heating unit 39 for heating the fixing roller 36 are provided. The fixing roller 36 illustrated in FIG. 2 includes a cylindrical metal tube 40 made of aluminum or carbon steel and a release layer 41 laminated on the outer peripheral surface of the metal tube 40. The pressure roller 37 includes a cylindrical cored bar 42 made of a metal such as aluminum or carbon steel, an elastic layer 43 made of silicone rubber or the like fixed to the outer peripheral surface of the cored bar, and the elastic layer 43 It is comprised by the mold release layer 44 laminated | stacked on the outer peripheral surface. The temperature detection unit 38 includes, for example, a thermistor that is in contact with the peripheral surface of the fixing roller 36, or another temperature sensor. The heating means 39 shown in FIG. 2 includes a main heating member 39A that generates heat when power is supplied from a main power source, which will be described in detail later, and an auxiliary heating member 39B that generates heat when power is supplied from an auxiliary power source. The heating members 39A and 39B are disposed inside the fixing roller 36. As the heating members 39A and 39B, for example, a halogen heater, a nichrome wire heater, an IH heater, or the like can be used.

  During the toner image fixing operation, the fixing roller 36 is driven to rotate counterclockwise in FIG. 2 by a driving device (not shown), and the pressure roller 37 is rotated in the clockwise direction in FIG. To do. At this time, the fixing roller 36 is heated by the heating unit 39 in a manner described later. The long recording medium P carrying the toner image T is passed through the nip portion N between the fixing roller 36 and the pressure roller 37 in a direction in which the toner image T is in contact with the fixing roller 36. Heat and pressure are applied to the toner of the image T to fix the toner image on the long recording medium P.

  In the fixing device 29 shown in FIG. 2, since the long recording medium P having a long length passes between the fixing roller 36 and the pressure roller 37, the heat of the fixing roller 36 is applied to the long recording medium P. Continue to be robbed for a long time. For this reason, while the long recording medium P passes between the fixing roller 36 and the pressure roller 37, the temperature of the fixing roller 36 may be lower than the temperature suitable for fixing.

Therefore, in the image forming apparatus of this example, as described above, the heating unit 39 provided in the fixing device 29 includes the main heating member 39A to which power is supplied from the main power source including the AC power source and the power from the auxiliary power source. When the temperature of the fixing roller that is determined to be unable to maintain the temperature necessary for fixing the toner image is set as the fixing temperature threshold T _lim , the temperature detecting means 38 detects the temperature. been if the temperature T _H of the fixing roller 36 is higher than the fixing temperature threshold value T _lim heats the fixing roller 36 by the main heating member 39A which generates heat receiving power from the main power supply, the temperature sensing means 38 If the temperature T _H of the detected fixing roller 36 is equal to or less than the fixing temperature threshold value T _lim is also an auxiliary heating member 39B, conductive from the auxiliary power to be described later in detail By supplying, to generate heat and the auxiliary heating member 39B, it is configured to rapidly heat the fixing roller 36 and the main heating member 39A by both the auxiliary heating member 39B. Below, an example of the control aspect relevant to these is demonstrated.

3 and 4 are flowcharts showing an example of a printing operation for forming an image on a long recording medium. 1 to 4, when a print command is inputted, first, the temperature T _H of the fixing roller 36 detected by the temperature detecting means 38, the fixing roller 36 and the pressure roller 37 of the nip N in the long recording medium , And a temperature at which the fixing operation of the toner image on the long recording medium can be started (hereinafter referred to as a paper passing temperature) T _t is determined (S1 in FIG. 3). if the temperature T _H of has reached the sheet-passable temperature T _t, the start of rotation of the fixing roller 36 and the pressure roller 37 shown in FIG. 2, fixing a long recording medium P bearing the toner image T The toner image is fed between the roller 36 and the pressure roller 37, and the toner image fixing operation is started (S3 in FIG. 3). The fixing operation of the toner image is performed from the time when the leading edge of the long recording medium enters the nip portion N between the fixing roller 36 and the pressure roller 37 to the time when the trailing edge of the long recording medium exits the nip portion. It is an operation between.

On the other hand, in S1, when the temperature T _H of the fixing roller 36 does not reach the sheet-passable temperature T _t, and heat the fixing roller 36 by the power from the main power supply continues to supply the main heating member 39A (in FIG. 3 S2) and S1 → S2 are repeated. At this stage, power is not supplied from the auxiliary power source to the auxiliary heating member 39B, and the fixing roller 36 is heated only by the main heating member 39A. Further, the temperature at which paper can be passed varies depending on the length of the long recording medium. The longer the length of the long recording medium, the higher the energizable temperature. The energizable temperature is, for example, about 160 ° C. to 200 ° C. The temperature _TH of the fixing member or the fixing roller 36 is the temperature of the surface of the fixing member or the fixing roller 36.

After the fixing operation is started, the temperature T _H is whether it is less fixing impossible temperature T _NG that can not fix the toner image _(e.g., 140 ° C.) of the fixing roller 36 is determined (S4 in FIG. 4), the fixing roller 36 when the temperature T _H of equal to or less than the fixing inability temperature, interrupts the printing operation (S5 in Fig. 3). In this case, the recording medium fed from one of the roll papers is immediately cut by the cutter unit 23 or 24, and the toner image forming operation on the photosensitive member 9 is stopped, and the recording medium is discharged. The paper part 32 or 33 is discharged. In this way, the long recording medium carrying the unfixed toner image is prevented from continuing to be discharged as it is. After the printing operation is interrupted, a message is displayed on the operation unit provided in the image reading unit 3 to prompt the user to reset the sheet passing temperature _Tt to a large value. In S6 of FIG. 3, the user can pass the sheet. When it is determined that the temperature T _t has been largely reset, the process proceeds to S2, and the operation from S1 described above is resumed. If the user does not reset the paper passing temperature, the printing operation is terminated.

On the other hand, in S4 of FIG. 3, if the temperature T _H of the fixing roller 36 is long above the fixing non temperature T _NG, the process proceeds to S7 in FIG. 3, by a sensor not shown, the trailing edge of the elongated recording medium fixing Whether or not the nip portion between the roller 36 and the pressure roller 37 has been exited, that is, whether or not the long recording medium has finished passing the sheet passing between the fixing roller 36 and the pressure roller 37 to complete the fixing operation. Make a decision. When the passing of the long recording medium is completed and the fixing operation of the toner image is completed, the rotation of the fixing roller 36 and the pressure roller 37 is temporarily stopped (S8 in FIG. 3), and then the set number of sheets is set. The arrival is determined (S9 in FIG. 3), and if not reached, the operation from S1 is repeated, and if it has reached, the printing operation is terminated.

When the trailing end of the long recording medium is not out yet the nip portion N between the fixing roller 36 and the pressure roller 37, a fixing operation of the toner image is not completed, the temperature T _H of the fixing roller 36 Is determined to be equal to or lower than the fixing temperature threshold T _lim (for example, 150 ° C.) (S10 in FIG. 4). If the temperature T _H of the fixing roller 36 was judged to be higher than the fixing temperature threshold value T _lim, without supplying power to the auxiliary heating member 39B, while heating the fixing roller 36 by the main heating member 39A, The toner image fixing operation is continued (S14 in FIG. 4). On the other hand, the temperature T _H of the fixing roller 36, when it becomes less than the predetermined fixing temperature threshold value T _lim is determined not to maintain the temperature necessary for fixing the toner image, the power to the auxiliary heating member 39B from the auxiliary power And the main heating member 39A and the auxiliary heating member 39B generate heat to heat the fixing roller 36. Thus, it is possible to provide greater heat the fixing roller 36, it is possible to maintain the temperature T _H of the fixing roller 36 to a temperature suitable for fixing the toner image.

As described above, in the image forming apparatus of this example, a long recording is performed between the fixing roller 36 and the pressure roller 37 while heating the fixing roller 36 only by the main heating member 39A supplied with power from the main power source. when passed through a medium P is performed fixing the toner image, the temperature T _H of the fixing roller 36 detected by the temperature detecting means 38, a predetermined being determined not to maintain the temperature necessary for fixing the toner image When the temperature is equal to or lower than the fixing temperature threshold T _lim , power is supplied from the auxiliary power source to the auxiliary heating member 39B, and the fixing roller 36 is also heated by the auxiliary heating member 39B.

At that time, the temperature T _H of the fixing roller 36 is sharply decreased, and if the temperature T _H is equal to or less than the fixing temperature threshold value T _lim, the temperature T _H is gradually reduced to a fixing temperature threshold value of the fixing roller 36 In some cases, the temperature of the fixing roller 36 is less than T _lim unless the fixing roller 36 is heated by applying a larger amount of heat to the fixing roller 36 than in the latter case. The temperature may be lower than the temperature suitable for fixing an image.

In view of this, in the image forming apparatus of this example, a plurality of auxiliary power sources that can be switched between serial connection and parallel connection are provided, and the inclination of the change in temperature of the fixing roller 36 detected by the temperature detection means 38 ( Calculation means for calculating (change amount of fixing roller temperature T _H per unit time) dT _H / dt = K _T is provided. Slope is predetermined _| Then, the slope K _T of the change in the fixing roller temperature T _H detected by the temperature detecting means 38 is calculated in increments of a predetermined time, in S11 of FIG. 4, the absolute value of the slope | K T It is determined whether or not the threshold value | K _Tlim | is _{equal to} or greater than the threshold value | K _Tlim |, and when the absolute value | K _T | of the slope is smaller than the slope threshold value | K _Tlim | The power is supplied to the auxiliary heating member 39B from the plurality of auxiliary power supplies (S12 in FIG. 4), and the power from the main power supply is supplied to the main heating member 39A, so that the main heating member 39A and the auxiliary heating member are supplied. The fixing operation of the toner image is continued while heating the fixing roller 36 with both 39B (S14 in FIG. 4). On the other hand, when the absolute value of inclination | K _T | is _{equal to} or _larger than the inclination threshold value | K _Tlim |, the auxiliary power control means connects a plurality of auxiliary power supplies in series, and the plurality of auxiliary power supplies to the auxiliary heating member 39B. In addition to supplying power (S13 in FIG. 4), power from the main power source is supplied to the main heating member 39A, and the fixing roller 36 is heated by both the main heating member 39A and the auxiliary heating member 39B. The fixing operation is continued (S14 in FIG. 4). When a plurality of auxiliary power supplies are connected in series, a larger amount of power can be supplied to the auxiliary heating member 39B than when the plurality of auxiliary power supplies are connected in parallel. giving a large amount of heat to the roller 36, the temperature T _H of the fixing roller 36 can be prevented to become lower than the temperature suitable for the fixing of the toner image.

As described above, in the image forming apparatus of this example, the heating unit 39 of the fixing device 29 has a plurality of auxiliary units that can be switched between the main heating member 39A to which power is supplied from the main power source and the series connection and the parallel connection. The auxiliary heating member 39B is supplied with power from a power source, and the fixing roller 36 and the pressure roller 37 are heated while the fixing roller 36 is heated only by the main heating member 39A supplied with power from the main power source. when passed through the elongated recording medium is performed fixing the toner image therebetween, it determines that the temperature T _H of the fixing roller 36 detected by the temperature detecting means 38 can not be maintained the temperature necessary for fixing the toner image when it becomes equal to or lower than a predetermined fixing temperature threshold value T _lim is, the absolute value of the slope of the temperature change of the fixing roller 36 | K T _| is a predetermined gradient threshold value | K _{Tlim |} when at least a plurality of auxiliary Connect a source in series to supply electric power to the auxiliary heating member 39B from the plurality of auxiliary power supply, the absolute value of the slope of the temperature change of the fixing roller 36 | smaller than _| K T _| inclination threshold | K _Tlim In some cases, there is provided auxiliary power output control means for connecting a plurality of power supplies in parallel and supplying power from the plurality of auxiliary power supplies to the auxiliary heating member 39B. The specific configuration of the auxiliary power output control means will be described later.

According to the above-described configuration, especially without using a fixing roller 36 having a large heat capacity, during the fixing operation of the toner image on the elongate recording medium, the temperature of the temperature T _H of the fixing roller 36 is suitable for fixing a toner image Can be prevented.

  As the auxiliary power source described above, it is desirable to use a chargeable / dischargeable electric double layer capacitor or a fuel cell that can be used repeatedly by replacing the fuel.

  Next, a more specific example of the printing operation described above will be clarified with reference to FIGS.

FIGS. 5 to 10 show an example in which an electric double layer capacitor is used as an auxiliary power source. FIGS. 5 and 6 show that the fixing roller 36 only generates heat from the main heating member supplied with power from the main power source. The operation example in the case of heating is shown. 5 and 6, at time t _0, power from the main power supply consisting of an AC power source to the main heating member 39A starts to be supplied. This fixing roller 36 generates heat is the main heating member 39A is heated by, as shown in FIG. 5 (A), the temperature T _H is above the sheet passing possible temperature T _t of the fixing roller 36 at the time of t ₁ The start-up operation of the fixing device 29 is finished. In the example shown here, the fixing roller 36 is heated without causing the auxiliary heating member 39B to generate heat during the start-up operation, but power is also supplied to the auxiliary heating member 39B from an auxiliary power source including an electric double layer capacitor. If the auxiliary heating member 39B also generates heat, the startup time of the fixing device 29 can be further shortened.

After completion of the start-up operation of the fixing device 29 as described above, such that the temperature T _H of the fixing roller 36 is maintained at a sheet-passable temperature T _t, the power supply is turned on to the main heating member 39A, It is turned off ((C) in FIG. 6). This state is a standby state of the fixing device 29. At this time, when the charging voltage of the electric double layer capacitor is detected by a voltage sensor (not shown) and there is room for charging in the electric double layer capacitor, When power is not supplied from the power source to the main heating member 39A, the electric double layer capacitor is charged ((C) and (E) in FIG. 6). As a result, the electric double layer capacitor can be efficiently charged, and a large amount of electric power can be secured when the electric double layer capacitor is used. During the start-up operation and standby, the fixing roller 36 and the pressure roller 37 do not rotate and are stopped.

The rotation of the fixing roller 36 and the pressure roller 37 at the time of t ₂ is started in FIG. 5 and FIG. 6, the feed of the elongated recording medium to the nip portion N between the fixing roller 36 and the pressure roller 37 Is started. The passing of the long recording medium to the nip portion N is started, and the fixing operation of the toner image on the long recording medium is started. As shown in FIG. 6C, the reason why the power consumption of the main heating member 39A is less after the start of the fixing operation than when the main heating member 39A is started up is that the AC power supply is increased with the start of the fixing operation. This is because the AC power of the main power source is converted to DC power and used for the rotation operation of the fixing roller 36.

When the fixing operation at the time of t ₂ is started, since the heat of the fixing roller 36 is absorbed by the elongate recording medium, as shown in FIG. 5 (A), the temperature T _H of the fixing roller 36 While gradually decreases, in the operation example shown in FIG. 5 and FIG. 6, the temperature T _H of the fixing roller 36, it becomes less fixing temperature threshold value T _lim is determined not to maintain the temperature necessary for fixing the toner image rather, to end the fixing operation at the time of t _3. That is, at this time, the trailing end of the long recording medium exits the nip portion N between the fixing roller 36 and the pressure roller 37, and the rotation of the fixing roller 36 and the pressure roller 37 is stopped.

Upon completion of the fixing operation, the main heating member 39A, power from the main power is supplied, the temperature T _H rises of the fixing roller 36, the temperature of the fixing roller 36 at the time of t ₄ T _H is fed possible temperature T _t ((A) in FIG. 5 and (C) in FIG. 6). On subsequent stand, so that the temperature T _H of the fixing roller 36 is maintained at a sheet-passable temperature T _t, the power supply to the main heating member 39A from the main power supply is turned on, it is turned off ((C in FIG. 6 )) If there is still room for charging in the electric double layer capacitor, the electric double layer capacitor is charged when power is not supplied from the main power source to the main heating member 39A ((C) and (E) in FIG. 6). )).

Further, the time from time t ₃ to t _4, and also supplied the electric power from the electric double layer capacitor to the auxiliary heating member 39B, both the heating member 39A, when configured to heat the fixing roller 36 by 39B, fixing temperature T _H of the roller 36 it is possible to shorten the time to reach the sheet-passable temperature T _t.

In the operation example shown in FIGS. 7 and 8, and from time t ₀ to t _2, t ₃ subsequent operations, operation and change is not shown in FIGS. Different place, at time _{T 1,} in that the temperature _{T H} of the fixing roller 36 is equal to or less than the fixing temperature threshold value _{T lim.} At this time, as can be seen from FIG. 7B, since the absolute value | K _T | of the temperature change of the fixing roller 36 is smaller than the inclination threshold value | K _Tlim |, a plurality of electric double layer capacitors are arranged in parallel. While being connected and supplying AC power from the main power source to the main heating member 39A, power is supplied from the plurality of electric double layer capacitors to the auxiliary heating member 39B to cause the auxiliary heating member 39B to generate heat, and both heating members 39A, 39B As a result, the fixing roller 36 is heated. Therefore, as can be seen from FIGS. 7C and 8D and 8E, the total consumption of the heating means 39, which is the sum of the power consumption of the main heating member 39A and the power consumption of the auxiliary heating member 39B. power is discontinuously increased at the time of T _1. Since the output of the electric double layer capacitor decreases as the discharge continues, the total power consumption of the heating means 39 gradually decreases from the time T ₁ ((C) in FIG. 7 and (E) in FIG. 8).

  Further, as can be seen from FIGS. 8E and 8F, when electric power is supplied from the electric double layer capacitor to the auxiliary heating member 39B, the electric double layer capacitor is not charged. For this reason, since all the AC power of the main power source can be supplied to the main heating member 39A, the fixing roller 36 can be effectively heated to raise its temperature.

In the operation example shown in FIGS. 9 and 10, in FIG. (A), as can be seen from (B), temperature fixing temperature threshold value T _lim next fixing roller 36 at time T _1, the fixing roller at this time The absolute value | K _T | of the temperature change gradient of 36 is equal to or greater than the gradient threshold value | K _Tlim |. For this reason, a plurality of electric double layer capacitors are connected in series, and AC power is supplied from the main power source to the main heating member 39A, while large power is supplied from the plurality of electric double layer capacitors connected in series to the auxiliary heating member 39B. Then, the auxiliary heating member 39B generates heat. Since power is supplied to the auxiliary heating member 39B from the electric double layer capacitors connected in series, as can be seen from FIG. 10E, the power consumption of the auxiliary heating member 39B is as shown in FIG. As shown in FIG. 9C, the total power consumption of the heating means 39 is larger than in the case of FIG. 7C. Accordingly, the fixing roller 36 can be heated more rapidly and its temperature can be raised than when a plurality of electric double layer capacitors are connected in parallel and the electric power is supplied to the auxiliary heating member 39B.

  Other operations in the example shown in FIGS. 9 and 10 are the same as those shown in FIGS.

11 and 12 show an operation example when a fuel cell is used as an auxiliary power source. Again, at time T _1, the temperature T _H of the fixing roller 36 becomes less fixing temperature threshold value T _lim, the absolute value of the slope of the temperature change is not shown in this case FIG fixing roller 36 | K T _| is It is _{assumed that the} inclination threshold value is smaller than | K _Tlim |. Accordingly, also in this case, a plurality of fuel cells are connected in parallel, and power is supplied from the plurality of fuel cells to the auxiliary heating member 39B while supplying AC power from the main power source to the main heating member 39A. The total power consumption of the heating means 39 at this time is the sum of the power consumption of the main heating member 39A and the power consumption of the auxiliary heating member 39B ((B) of FIG. 11 and (C), (D) of FIG. 12). .

  As can be seen from (E) of FIG. 12, since the fuel cell reduces the fuel by discharging, the remaining amount of fuel is constantly monitored, the remaining amount of fuel is displayed on the operation unit, and the remaining amount is indicated to the user. It is necessary to report. It is desirable that the fuel of the fuel cell be configured to be replaceable like a cartridge type so that it can be replaced when the user recognizes that the remaining amount of fuel is low. Thus, the fuel cell preferably includes means for detecting the remaining amount of fuel, means for displaying the remaining amount of fuel, and means for prompting the replacement of fuel when the remaining amount of fuel falls below a certain value.

  Next, specific configuration examples of the auxiliary power supply and the auxiliary power supply output control means will be described.

FIGS. 13 to 16 show auxiliary power output control means for connecting two electric double layer capacitors C1 and C2 in parallel or in series and supplying electric power from these electric double layer capacitors C1 and C2 to the auxiliary heating member 39B. It is a circuit diagram which shows an example. Each electric double layer capacitor C1, C2 is composed of a plurality of capacitor cells. Main switch _{S 5} is turned on the electric power supplied from the main power source 45 consisting of AC power to the main heating member 39A, off. The charger 46 serves to charge the two electric double layer capacitors C1 and C2 with electric power supplied from the main power supply 45. The switch _{S 2} switches and charging of the electric double layer capacitors C1, C2, power supply from the electric double layer capacitors C1, C2 to the auxiliary heating member 39B. Detection signal generated by the temperature detecting means 38 consisting of a contact with the thermistor on the surface of the fixing roller 36 is taken into CPU 47, a command from the CPU 47, the respective switches S ₁ to S ₅ are switching controlled.

Figure 13 shows a state in which the power from the main power source 45 by closing the main switch S ₅ is supplied to the main heating member 39A, and heating the main heating member 39A. At this time, the switches S ₃ and S ₄ connect both the electric double layer capacitors C 1 and C 2 in parallel, and the switch S ₂ is switched to the switch S ₁ side, but the switch S ₁ is turned off. The electric power of the double layer capacitors C1 and C2 is not supplied to the auxiliary heating member 39B.

During charging of the electric double layer capacitors C1, C2, as shown in FIG. 14, the main switch S ₅ is turned off, are cut off the power supply to the main heating member 39A from the main power source 45. At the same time, the switch S ₂ is switched to the side of the charger 46, the charger 46 charges the electric double layer capacitor C1, C2 in the power supplied from the main power supply 45.

When performing the fixing operation of the toner image while heating the fixing roller 36 in only the main heating member 39A, the temperature T _H of the fixing roller 36 becomes less fixing temperature threshold value T _lim detected by the temperature detecting means 38, moreover CPU47 the absolute value of the slope of the temperature change of the fixing roller 36, which is calculated by _| K T | K _Tlim | | is threshold slope is smaller than the main switch S ₅ is turned on the main power supply 45 as shown in FIG. 15 with power from is supplied to the main heating member 39A, while both the electric double layer capacitors C1, C2 are connected in parallel, the switch S ₂ is switched to the side of the switch S _1, the switch S ₁ is closed. As a result, power from the main power supply is supplied to the main heating member 39A, and power from the electric double layer capacitors C1 and C2 connected in parallel is supplied to the auxiliary heating member 39B, so that both the heating members 39A and 39B Fever.

Temperature _{T H} of the fixing roller 36 becomes less fixing temperature threshold value _{T lim,} and the absolute value of the slope of the temperature change of the fixing roller 36 | _{K T} | inclination threshold _{| K Tlim} | when is not less than the switch _S 3, S ₄ is both an electric double layer capacitor C1, C2 are switched as shown in FIG. 16 are connected in series. Other states are the same as in FIG. For this reason, power from the main power supply is supplied to the main heating member 39A, and power is supplied to the auxiliary heating member 39B from both electric double layer capacitors C1 and C2 connected in series.

  FIG. 17 is a circuit diagram when two fuel cells C3 and C4 are used as auxiliary power supplies. In this case, the charger 46 shown in FIGS. 13 to 16 is not provided. In FIG. 17, the switches S1 and S5 are closed, the fuel cells C3 and C4 are connected in parallel, and the power from the fuel cells C3 and C4 and the main power supply 45 are supplied to the auxiliary heating member 39B and the main heating member 39A, respectively. It shows the state being done. When the power of the main power supply 45 is supplied to the main heating member 39B and the power from the fuel cells C3 and C4 is not supplied to the auxiliary heating member 39B, the switch S1 is opened and the fuel cells C3 and C4 are connected in series. The switches S3 and S4 are switched in the same manner as in FIG.

  The auxiliary power supply output control means including the CPU 47 shown in FIGS. 13 to 17 and the auxiliary power supply are integrally assembled, so that a plurality of auxiliary power supplies that can be switched between series connection and parallel connection, and the temperature of the fixing member are predetermined. When the absolute value of the inclination of the temperature change of the fixing member is equal to or greater than a predetermined inclination threshold when the temperature is equal to or lower than the fixing temperature threshold, a plurality of auxiliary power supplies are connected in series to fix from the plurality of auxiliary power supplies. When electric power is supplied to the auxiliary heating member for heating the member and the absolute value of the inclination of the temperature change of the fixing member is smaller than the inclination threshold value, a plurality of power sources are connected in parallel, and the fixing member is heated from the plurality of auxiliary power sources. The auxiliary power supply 48 for the fixing device can be configured to include auxiliary power supply output control means for supplying power to the auxiliary heating member.

  The fixing device having the fixing member made of the fixing roller 36 and the pressure member made of the pressure roller 37 has been described above, but has the fixing member made of a fixing belt that is wound around a plurality of support rollers and driven to travel. The present invention can also be applied to a fixing device or a fixing device in which a pressure member is also configured as a pressure belt.

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus. FIG. 3 is an enlarged cross-sectional view of a fixing device. 6 is a flowchart illustrating an example of an operation mode of the image forming apparatus. FIG. 6 is a flowchart illustrating an example of an operation mode of the image forming apparatus. FIG. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. 6 is a timing chart illustrating a more specific operation example of the image forming apparatus. It is a circuit diagram of a main power supply, an auxiliary power supply, and a fixing device. It is a circuit diagram of a main power supply, an auxiliary power supply, and a fixing device. It is a circuit diagram of a main power supply, an auxiliary power supply, and a fixing device. It is a circuit diagram of a main power supply, an auxiliary power supply, and a fixing device. It is a circuit diagram of a main power supply, an auxiliary power supply, and a fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 29 Fixing device 38 Temperature detection means 39 Heating means 39A Main heating member 39B Auxiliary heating member 45 Main power supply 48 Auxiliary power supply device C1, C2 Electric double layer capacitor C3, C4 Fuel cell N Nip part P Long recording medium T Toner image

Claims (5)

A toner image is formed on the image carrier, the toner image is transferred to a long recording medium longer than a standard size, and the toner image transferred to the long recording medium is fixed to the long recording medium by a fixing device. In the image forming apparatus, the fixing device includes a fixing member, a pressure member pressed against the fixing member, a temperature detecting unit that detects the temperature of the fixing member, and a heating unit that heats the fixing member. Then, a long recording medium carrying a toner image is passed through the nip portion between the fixing member and the pressure member, and heat and pressure are applied to the toner of the toner image during the passage so that the toner image is transferred to the long recording medium. In the image forming apparatus fixed to
The heating means includes a main heating member supplied with power from a main power source, and an auxiliary heating member supplied with power from a plurality of auxiliary power sources that can be switched between series connection and parallel connection. An arithmetic means for calculating the inclination of the temperature change of the fixing member detected by the temperature detecting means, and the fixing member and the heating member while heating the fixing member only by the main heating member supplied with power from the main power source. When fixing the toner image by passing a long recording medium between the pressure members, it is determined that the temperature of the fixing member detected by the temperature detecting unit cannot maintain the temperature necessary for fixing the toner image. When the absolute value of the inclination of the temperature change of the fixing member is equal to or greater than a predetermined inclination threshold when the temperature is equal to or lower than the predetermined fixing temperature threshold, the plurality of auxiliary power supplies are connected in series, From auxiliary power When the electric power is supplied to the auxiliary heating member and the absolute value of the inclination of the temperature change of the fixing member is smaller than the inclination threshold, the plurality of power supplies are connected in parallel, and the auxiliary heating member is connected from the plurality of auxiliary power supplies. An image forming apparatus comprising: an auxiliary power supply output control means for supplying power to the image forming apparatus. The image formation according to claim 1, wherein the auxiliary power source is configured by a chargeable / dischargeable electric double layer capacitor, and charges the electric double layer capacitor when electric power is not supplied to the main heating member from the main power source. apparatus. The image forming apparatus according to claim 1, wherein the auxiliary power source is configured by a fuel cell that can be used repeatedly by changing fuel. 4. The image forming apparatus according to claim 3, wherein the fuel cell includes means for detecting a remaining amount of fuel, means for displaying the remaining amount of fuel, and means for prompting replacement of the fuel when the remaining amount of fuel falls below a certain value. apparatus. A plurality of auxiliary power supplies that can be switched between series connection and parallel connection, and when the temperature of the fixing member is equal to or lower than a predetermined fixing temperature threshold, the absolute value of the inclination of the temperature change of the fixing member is a predetermined inclination threshold. When the above is true, the plurality of auxiliary power supplies are connected in series to supply power from the plurality of auxiliary power supplies to the auxiliary heating member for heating the fixing member, and the absolute value of the inclination of the temperature change of the fixing member is When the inclination threshold value is smaller than the threshold value, the plurality of power supplies are connected in parallel, and the auxiliary power supply output control means for supplying power from the plurality of auxiliary power supplies to the auxiliary heating member for heating the fixing member is used for a fixing device. Auxiliary power supply.

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