JP5008283B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus using the same.

Conventionally, a heating element is provided with a main heating element and an auxiliary heating element, the main heating element is supplied with power from the main power supply, and the auxiliary heating element is supplied with power from the auxiliary power supply having a capacitor. A fixing device and an image forming apparatus are known that charge an auxiliary power supply when no power is supplied from the apparatus to the main heating element, and do not charge the auxiliary power supply when power is supplied from the main power supply to the main heating element (for example, Patent Document 1). This technology increases the power saving effect with a simple configuration and reduces the volume of the auxiliary power source to reduce the installation space.
JP 2003-257590 A

  The present invention develops the above-described technology so that the power of an external power source can be effectively used to charge a power storage device such as a capacitor, and the fixing quality during image formation in a low-temperature environment is improved. For the purpose.

A fixing device according to a first aspect of the present invention includes:
In a fixing device including a heating unit and a fixing member heated by the heating unit, and fixing a toner image on a recording medium by heating the fixing member.
A main power supply connected to an external power supply to supply power to the heating unit;
A power storage device that is charged by the external power source and supplies power to the heating unit at the time of temperature rise of the fixing member and a sheet passing operation ;
Provided and the ambient temperature detecting means for detecting the environmental temperature, and
Even if there is fed instruction after top temperature elevation before Symbol fixing member, when the temperature where the environmental temperature detecting unit detects is lower than a predetermined value,
Charging the power storage device from the external power source after the temperature rise of the fixing member and before starting the sheet passing operation based on the sheet passing instruction ;
It is characterized by that.

Those according to the claim 2 is the fixing device according to claim 1, when the temperature where the environmental temperature detecting means has detected the predetermined value or more, the electric storage after the upper temperature elevation of the fixing member A sheet passing operation based on the sheet passing instruction is started without charging the apparatus.

Which according to the claim 3 is the fixing device according to claim 1 or 2, wherein the power storage device, when they are power supplied to the heating unit from the main power supply to the power supply to the heating unit and wherein and Turkey.

According to Claim 4, in the fixing device according to any one of Claims 1 to 3 , charging from the external power source to the power storage device is performed when the voltage of the power storage device becomes a predetermined voltage. It is characterized by stopping at .

According to a fifth aspect of the present invention, in the fixing device according to any one of the first to fourth aspects, the power storage device is an electric double layer capacitor .

An image forming apparatus according to claim 6 includes an image forming unit and the fixing device according to any one of claims 1 to 5.

According to claim 7,
A main power supply;
A fixing device to which power is supplied from the main power supply device ;
An auxiliary power supply device having a power storage device that is charged by the main power supply device and supplies electric power to the fixing device at least when the temperature of the fixing device rises and during a sheet passing operation;
In an image forming apparatus comprising :
Even when there is a paper passing command after the temperature rise of the fixing device, if the temperature detected by the environmental temperature detection means is lower than a predetermined value, the temperature is passed after the temperature of the fixing device is raised. Charging the power storage device from the main power supply device before the paper feeding operation by the paper command is started ;
It is characterized by that.

The present invention relates to and continuous paper feed o'clock when launching Fixing temperature, it is possible to charge the power storage device by effectively utilizing the power of the external power source, it can be effectively utilized power. Further, the fixing quality at the time of image formation in a low temperature environment can be improved.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  1 to 9 show a first embodiment of the present invention. 1 is a schematic cross-sectional view of an overall configuration of an image forming apparatus using a fixing device according to the present invention, FIG. 2 is a cross-sectional configuration diagram of a fixing device that can be an object of the present invention, and FIG. 3 is a diagram of the fixing device of FIG. It is a block diagram which shows a circuit structure typically. In the figure, reference numeral 41 denotes an example of an image carrier made of a rotating body, which shows a drum-shaped photoconductor. Around the photosensitive member 41, a developing device 44 including a charging device 42 composed of a charging roller, a mirror 43 constituting a part of the exposure means, and a developing roller 44a in the rotation direction indicated by an arrow in the drawing, A transfer device 48 that transfers the developed image onto transfer paper as the recording material P, a cleaning device 46 that includes a blade 46 a that slides on the peripheral surface of the photoreceptor 41, and the like are disposed. On the photosensitive member 41, the exposure light Lb is scanned through the mirror 43 between the charging device 42 and the developing roller 44a. The irradiation position of the exposure light Lb is referred to as an exposure unit 150.

  The transfer device 48 is provided to face the lower surface of the photoreceptor 41. A portion facing the transfer device 48 is a transfer portion 47. A pair of registration rollers 49 are provided at a position upstream of the transfer portion 47 in the rotation direction of the photosensitive member 41. A recording material P guided by a conveyance guide (not shown) and stored in a paper supply tray (not shown) is sent out from the paper supply roller 110 toward the registration roller 49. Further, the fixing device 10 is disposed at a position further downstream in the rotation direction of the photosensitive member 41 of the transfer unit 47.

  Image formation in this image forming apparatus is performed as follows. The photosensitive member 41 starts to rotate, and during this rotation, the photosensitive member 41 is uniformly charged by the charging device 42 in the dark, and the exposure unit 150 is irradiated and scanned with the exposure light Lb to form a latent image corresponding to the image to be created. Form. The latent image is moved to the developing device 44 by the rotation of the photoconductor 41, where the developing device 44 visualizes it with toner to form a toner image.

  On the other hand, the feeding of the recording material P on the paper feeding tray is started by the paper feeding roller 110, and the recording material P is temporarily stopped at the position of the pair of registration rollers 49 via the conveyance path indicated by the broken line in the drawing, and the photoconductor The delivery timing is set so that the toner image on the toner 41 coincides with the transfer portion 47. Then, the registration roller 49 rotates at a suitable timing, and the recording material P that has been stopped is sent out and conveyed toward the transfer unit 47. Then, the toner image on the photoconductor 41 and the recording material P are matched with each other by the transfer unit 47, and the toner image is transferred onto the recording material P by applying an electric field by the transfer device 48.

  The recording material P carrying the toner image in the image forming portion around the photoreceptor 41 is then sent out toward the fixing device 10. The toner image on the recording material P is fixed on the recording material P while passing through the fixing device 10, and the recording material P that has been fixed on the toner image is discharged to a paper discharge unit (not shown).

  On the other hand, residual toner that is not transferred by the transfer unit 47 and remains on the photoconductor 41 reaches the cleaning device 46 along with the rotation of the photoconductor 41 and is cleaned while passing through the cleaning device 46. The photoconductor 41 prepares for the next image formation in that state.

  As shown in FIG. 2, the fixing device 10 includes a fixing member 14, a pressure member 15, a heating unit 1 in the fixing member 14, and a fixing temperature detection unit 8 outside the fixing member 14. Further, the fixing device 10 has a control unit 60 for controlling power supplied from the auxiliary power supply device 3 to the fixing device 10 in accordance with temperature information from the fixing unit temperature detecting unit 8 as a control system.

  The fixing unit temperature detection unit 8 is configured by an appropriate unit such as a thermistor, a thermocouple, an infrared temperature detection device, and the like, and sends temperature information to the control unit 60. Based on the temperature information obtained from the fixing unit temperature detection unit 8, the control unit 60 can control starting, stopping, and increasing / decreasing the amount of power supplied to the heating unit 1 of the fixing device 10. Further, as shown in the circuit configuration of FIG. 3, the illustrated fixing device 10 includes contacts (AC 6 a and DC 6 b) that are turned on and off based on a command from the control unit 60.

  The main power supply 2 that supplies power to the image forming apparatus obtains power from a commercial power supply that is an external power supply and supplies power to various units in each part of the image forming apparatus. As with general equipment, power can be supplied to each unit or the like in the image forming apparatus by inserting a plug of a power line into a commercial power outlet.

  The auxiliary power supply device 3 has a power storage device such as an electric double layer capacitor (or an electric double layer capacitor), and can supply the power stored by charging from the main power supply device 2 in addition to the power supplied from the main power supply device 2. Thus, large power can be supplied to the image forming apparatus. It should be noted that not only the electric double layer capacitor but also a secondary battery such as Li ion or nickel hydride, a pseudo-capacitance capacitor using oxidation-reduction, or the like can be used for power storage in the auxiliary power supply device 3.

  The heating unit 1 in the fixing member 14 includes heating elements 1a and 1b (AC heater 1a and DC heater 1b: hereinafter referred to as a main heating member 1a and an auxiliary heating member 1b), a main power supply device 2 and an auxiliary power source. In addition to the device 3, the charger 4, the charge / discharge switching unit 5, the main power control unit 6 a that controls the power supply from the main power source, and the auxiliary power control unit 6 b that controls the power supply from the auxiliary power device 3. Yes. The main heating member 1a is supplied with electric power from the main power supply device 2 and generates heat. On the other hand, the auxiliary heat generating member 1 b generates heat by supplying power from the auxiliary power supply device 3.

  The roller base of the fixing member 14 is preferably made of a metal such as aluminum or iron from the viewpoint of durability, deformation due to pressure, or the like. In addition, it is desirable to form a release layer on the roller surface to prevent adhesion with the toner, and it is desirable that the inner surface of the roller be blackened to efficiently absorb the heat of the halogen heater. . Further, although not shown, a belt fixing configuration in which a nip portion is formed by a belt instead of a roller may be used.

  The pressure member 15 forms an nip portion between the fixing member 14 by forming an elastic layer such as rubber on the core metal, and a recording material P such as paper on which an unfixed image is formed on the nip portion. By passing the paper, the toner image is fixed on the recording material P by heat and pressure. Further, a nip portion may be formed between the pressure member 15 and the fixing member 14 with a pressure roller having a foam layer. In this case, the heat of the fixing member 14 is not easily transmitted to the pressure roller due to the heat insulating effect of the foam layer, so that the temperature of the fixing member 14 can be raised quickly.

  The auxiliary power supply 3 is a power supply for charging power from the main power supply 2 and supplying power to the auxiliary heat generating member 1b. The power supplied from the main power supply device 2 can be stored by the charger 4 that supplies the power from the main power supply device 2 to the auxiliary power supply device 3 after voltage adjustment or AC / DC conversion, and the charge / discharge switching means 5 Auxiliary power can be supplied to the heating unit 1.

  Specifically, the main power supply device 2 obtains electric power from the outlet of a commercial power supply with the plug 51, and supplies power to the units of each part of the image forming apparatus. In Japan, the current capacity is limited to about 15 A at a voltage of 100 V, and the power from the main power supply 2 is often about 1500 W. It may have functions such as voltage adjustment, AC and DC rectification, and voltage stabilization.

  The auxiliary power supply device 3 is configured by connecting a plurality of capacitor cells made of, for example, electric double layer capacitors, and the electric power stored by charging from the main power supply device 2 is larger than that at the time of start-up or continuous paper passing. By adopting a configuration that supplies power when it is desired, it is possible to supply power exceeding the power supplied to the main power supply 2 to the image forming apparatus.

  The auxiliary power supply 3 as an example of the configuration is a module of 100 V by connecting 40 capacitor cells having a diameter of 35 mm and a length of about 120 mm in series with 2.5 V and 800 F, an internal resistance of 5 mΩ or less. Is used. In order to ensure the voltage balance of each cell when connected in series, it is possible to ensure long-term stability of operation by providing a voltage balance circuit (not shown). If the internal resistance is 5 mΩ or less, the voltage drop between the terminals of the auxiliary power supply 3 can be smaller than that of a secondary battery such as a lithium battery or a nickel metal hydride battery even at a large current exceeding 20 A at the time of startup. Moreover, since it is a small value among capacitors, large power can be obtained with a smaller number of capacitor cells, which is advantageous in terms of device size and cost.

  The auxiliary power supply 3 is a chargeable / dischargeable power supply, and uses an electric double layer capacitor that is a large-capacity capacitor. Unlike the secondary battery, the electric double layer capacitor does not involve a chemical reaction. Has the excellent feature of being long.

  In other words, an auxiliary power source using a general nickel-cadmium battery as a secondary battery requires several tens of minutes to several hours even if quick charging is performed. This was not practical because it could be realized only a few times. On the other hand, an auxiliary power source using a capacitor can be rapidly charged for several tens of seconds to several minutes, so the charging time is short, for example, printing is not performed, and there is a margin in the power supply of the main power source. It is possible to charge the battery at a certain time and increase the number of times of heating using the auxiliary power source to a practical number.

  Further, since the nickel-cadmium battery has 500 to 1000 charge / discharge cycles, it has a short life as an auxiliary power source for heating, and there is a problem in labor and cost of replacement. On the other hand, an auxiliary power source using a capacitor has a life of 10,000 times or more, and is less deteriorated by repeated charge and discharge. Also, unlike lead-acid batteries, there is no need for liquid replacement or replenishment, so there is almost no maintenance.

  In recent years, capacitors that can store a large amount of electric energy have been developed, and their use in electric vehicles and the like is also under consideration. For example, an electric double layer capacitor developed by Nippon Chemi-Con Co., Ltd. has a capacitance of about 2000 F at 2.5 V, and has a sufficient capacity for supplying power for several seconds to several tens of seconds. In addition, NEC Corporation has realized a capacitor of about 80F called a hypercapacitor (trade name). Furthermore, JEOL Ltd. increased the withstand voltage to 3.2 to 3.5 V and increased the energy density to 50 to 75 wh / kg, a technology called nanogate capacitor (trade name) that is 5 to 10 times the conventional one. Announcing.

  As described above, the heating unit 1 includes the main heat generating member 1a and the auxiliary heat generating member 1b. For this, a halogen heater can be used, and heat is generated by passing an electric current through a filament formed in the glass tube. I am letting. However, the present invention is not limited to the halogen lamp or the halogen heater, and induction heating may be used or a ceramic heater may be used. The main heat generating member 1a generates heat by supplying power from the main power supply device 2 as described above, and uses, for example, a 100V, 1200w halogen heater. As described above, the auxiliary heat generating member 1b generates heat by supplying power from the auxiliary power supply device 3. For example, two auxiliary heaters, 100V and 1000w halogen heaters, and 100V and 700w halogen heaters are connected in parallel. Constitute.

  The power supplied to the heating unit 1 as described above is configured to be supplied from the main power supply device 2 to the main heat generating member 1a of the heating unit 1, and the power is supplied from the auxiliary power supply device 3 to the auxiliary heat generating member 1b. Can be supplied. In the auxiliary power supply device 3, electric power can be stored in advance by the charger 4, and electric power can be supplied to the auxiliary heat generating member 1b at an arbitrary timing.

  In addition to supplying the power from the auxiliary power supply 3 to the heating unit 1 in addition to the main power supply 2, a large amount of power exceeding the power supplied by the main power supply 2 can be supplied to the heating unit 1. For this reason, as shown in FIG. 4A, the temperature rise time until the temperature of the heating unit 1 changes from room temperature to a predetermined temperature is higher than that using only the main power supply 2 and the main power supply 2 and the auxiliary power supply. The temperature raising time can be shortened by using 3 at the same time.

  Further, as shown in FIG. 4B, when the amount of heat taken away by the recording material such as paper by continuous paper passing is large, even if the power from the main power supply 2 alone is below the predetermined minimum temperature, the auxiliary power source When power is supplied from the device 3, the drop can be reduced. For this reason, it is possible to increase the speed of the machine with more paper passing per unit time.

  FIG. 5 is a diagram for explaining an example in which a high-speed machine capable of high-temperature temperature rise without the temperature drop of the fixing member 14 even when a thin roller is used. First, in an initial state, power is supplied from an external power source such as a commercial power source, and the auxiliary power supply device 3 having a large-capacity capacitor capable of rapid charging such as an electric double layer capacitor is charged. At the time of start-up, when the temperature of the fixing member 14 such as a fixing roller is raised from room temperature in a short time, in addition to the main power supply device 2, the power of the auxiliary power supply device 3 is supplied to the heating unit 1. The total power supplied to 1 can be supplied more than when only the main power supply device 2 is used, and thus the temperature of the heating member 1 can be raised in a short time. For example, an aluminum thin roller having a diameter of 40 mm and a thickness t of 0.7 mm is used as a fixing member, and 1200 W power from the main power source is applied to the main heat generating member 1 a with 1700 w heater power from the auxiliary power source. By supplying about 2900w of power, the rise time of 30 seconds with only the main power supply can be reduced to about 10 seconds.

  Note that since the auxiliary power source is a capacitor, the supply power gradually decreases from 1700 w due to a voltage drop during power feeding. Due to this feature, it is possible to adopt a configuration in which, when a predetermined time elapses, the power supply becomes very small, and when the temperature is raised to a temperature of 500 ° C. at which paper is ignited, the rate of temperature rise is reduced. Thereby, the structure which implement | achieves temperature rising safely for a short time can be provided.

  In order to ensure safety, it is desirable to install a safety device that shuts off the power supply circuit directly by a safety circuit such as a temperature fuse or a thermostat in the event that the system runs out of control.

  In addition, as a method of simply increasing the power, it is possible to increase the power by using two commercial power sources, or to use a secondary battery or a fuel cell, but these methods supply a large amount of power almost continuously. Therefore, when the temperature rise time is shortened, the reaction time of these safety circuits is slow and the temperature rise rate cannot be caught up. For this reason, when the safety circuit is activated, the temperature of the heating part becomes too high, and in the worst case, it may ignite. On the other hand, in a configuration using capacitors, the system runs out of control and control is not possible, and even if power supply continues, if the specified power is used up, the heat generation of the heat generating member ends, and the temperature rise stops naturally. Therefore, by using the capacitor as a heat source, it is possible to safely shorten the heating time.

  As for the sheet passing, since it is a thin roller, the roller temperature tends to decrease when the number of sheets passed per unit time is large, but it is possible to prevent the temperature drop by supplying auxiliary power in addition to the main power during sheet passing. Therefore, it is possible to provide an easy-to-use image forming apparatus that uses a thin roller even in a high-speed layer and has a short temperature rise time.

  For example, when only the 700 w heater, which is one of the two auxiliary heat generating members 1 b, is used during the passage of paper, for example, about 500 w is supplied from the main power supply to the main power supply after the rising discharge. It is possible. For this reason, even a thin roller, which normally has a limit of about 60 cpm, can prevent a temperature drop immediately after the sheet is passed, so that high-speed image formation at 75 cpm is possible.

  In addition, two auxiliary heating elements 1b may be used during the passage of paper, or one auxiliary heating element 1b may be used. However, since the large electric power can be supplied and the temperature controllability can be improved, As described above, a two-heater configuration and an operation in which one heater is used when paper is passed are desirable.

  Regarding charging, power is supplied from the main power supply device 2 to the auxiliary power supply device 3 in a standby state in which power supply from the main power supply device 2 has a margin. When a capacitor is used as an auxiliary power source, the charging time can be shortened to about several minutes. And if it is within several minutes during this charge, since a heating member does not cool, it does not need to use an auxiliary power supply, or it is in time for the charging power to the middle. For this reason, it is not necessary for the next user to wait for charging, and a comfortable function can be provided.

  As described above, by using a capacitor as an auxiliary power source for heating the heating unit 1 of the fixing device 10, an effect that cannot be obtained with a secondary battery can be obtained. Control and operation.

  An embodiment of the present invention in which the temperature of the fixing member 14 (hereinafter referred to as the fixing member temperature) T is raised to a predetermined target temperature T0 that can be fixed, and the operation at the time of raising the temperature is different depending on the fixing member temperature T. This will be described with reference to FIG.

  FIG. 6 shows a start condition and an end condition based on the temperature of the fixing member 14. First, as shown in a graph a (main + sub) in FIG. 6, when the temperature of the fixing member 14 is raised, the temperature T detected by the fixing member temperature detecting means 8 is a normal indoor environment temperature (such as an office). For example, when the power supply from the auxiliary power supply 3 is added to the power supplied from the main power supply device 2, a predetermined normal target time t0 (for example, about 10 seconds) can be achieved.

  By the way, immediately after the start-up, the remaining power of the auxiliary power supply 3 is reduced and the voltage is lowered, so that the supplied power is reduced even if a halogen heater having the same rated power is used. Since the power supply to the fixing member 14 is not performed, the auxiliary power supply 3 is charged during the interval between t1 and t2 between the start-up and the paper passing where the power supplied from the external power source becomes small. Can be increased.

  Further, for example, in a low-temperature environment such as a winter morning, when the amount of heat taken away from the fixing member 14 by the recording material to be passed is large, the temperature of the fixing member can be prevented by controlling as follows. Is possible.

  For example, if a heater rated at 100V and 700w is used up to 85V at the time of start-up, the power supply is about 500w at the time of passing the paper, but the auxiliary power supply 3 is charged immediately before the paper passing and the output voltage is set to 100V. , 700w can be output as a whole, and the influence of a temperature drop can be reduced. Of course, the auxiliary power supply 3 may be kept at an intermediate voltage (for example, about 95 V) without being charged up to 100 V, and can be appropriately set according to the environment.

  FIG. 7 is an AC power supply flow chart at the time of start-up. The start condition based on the fixing member temperature at the start-up, the end condition based on the fixing member temperature at the start-up, and the start condition based on the fixing member temperature at the time of paper feeding The termination condition based on the fixing member temperature at the time of paper feeding is shown. That is, the start-up is started after the fixing member temperature T is detected before the start-up (step 1), and it is determined whether or not the relationship between the fixing-member temperature T and the predetermined target temperature T0 is T ≦ T0. (Step 2) If T ≦ T0, the process proceeds to Step 6 to be described later. If T ≦ T0, the power supply to the heating unit 1 of the main power supply device 2 is turned ON (Step 3), and the fixing member temperature at the time of start-up T is detected (step 4), and it is determined whether or not the relationship between the fixing member temperature T and the predetermined target temperature T0 is T ≧ T0 (step 5). If not T ≧ T0, the process returns to step 3. If T ≧ T0, power supply to the heating unit 1 of the main power supply device 2 is turned off (step 6).

  FIG. 8 is a flowchart of DC charging / discharging at the time of start-up. The start condition based on the fixing member temperature at the time of start-up, the end condition based on the fixing member temperature at the time of start-up, the start of charging after the end, The start condition based on the fixing member temperature, the end of charging at the same time as the start, and the end condition based on the fixing member temperature at the time of paper feeding are shown. That is, start-up is started (step 1), the fixing member temperature T at the time of start-up is detected (step 2), and whether or not the relationship between the fixing member temperature T and a predetermined target temperature T0 is T ≧ T0. Judgment (step 3), if T ≧ T0, the power supply to the heating unit 1 of the auxiliary power supply 3 is turned on (step 10), and the power supply from the auxiliary power supply 3 is performed at the time of start-up, thereby the required time t0. Inside, the temperature of the fixing member 14 can be raised (graph a in FIG. 6), and then the process returns to step 2. If T ≧ T0 in step 3, the power supply to the heating unit 1 of the auxiliary power supply 3 is turned off (step 4). This is because the initial temperature of the fixing member 14 is high, so that the temperature can be increased in a short time without using the auxiliary power supply 3. Then, charging of the auxiliary power supply device 3 using an external power supply is started (step 5). When the voltage of the auxiliary power supply device 3 reaches an intended or required voltage, the charging is stopped (step 6), and the recording material is stopped. The fixing member temperature T is detected while passing P (step 7), and it is determined again whether T ≧ T0 (step 8). If T ≧ T0, the process proceeds to step 9, and the auxiliary power supply 3 is heated. The power supply to the unit 1 is turned off. This state is shown by a graph b in FIG. If T ≧ T0 in step 8, the power supply to the heating unit 1 of the auxiliary power supply 3 is turned on (step 11), and the process returns to step 7.

  Further, the control unit 60 supplies power to the auxiliary heating member 1b when the temperature of the fixing member rises, based on information from an operation information detection unit (not shown) of the image forming apparatus, and then assists before starting to pass the paper. Control that does not charge the power supply device 3 is performed. This is a case where the operation information of the image forming apparatus is based on, for example, information for passing a small size paper. For example, the auxiliary heating member 1b, which is a 100V, 700w rated heater, heats the entire sheet-passable area. However, in 700w, which is charged after startup and used at 100V, the non-sheet-passing area is excessively increased due to continuous passing of small size paper. While the problem of warming is likely to occur, the 500w used at 85V, which is not charged after startup, can avoid excessive temperature rise in the non-sheet passing area even during continuous sheet passing. In addition, the power is not charged when the environmental temperature is high as the operation information, and the power is not charged by detecting the number of printed sheets and not charging when the number of printed sheets is small. Consumption can be prevented.

  FIG. 9 is a timing chart showing an example of the fixing member temperature, AC power supply, DC power supply, and DC charge from the start of start-up to the end of paper passing. The control unit 60 charges the auxiliary power supply device 3 with an external power supply even after the start of continuous paper feeding. That is, as indicated by an arrow X in the figure, there is a mode in which DC discharge is not performed during continuous paper passing, but only AC charging is received. Therefore, the main power supply device 2 supplies power to the auxiliary power supply device 3 for the DC charge indicated by Y in the drawing. This makes it possible to shorten the charging time during standby by charging when there is no power required to read the original document, such as printer function operation, and there is sufficient power even during continuous paper feeding. Therefore, the situation in which charging is insufficient at startup and the temperature cannot be raised for a short time is reduced. Therefore, it is possible to provide an image forming apparatus with improved user convenience. Although not shown in the figure, when a second sheet is passed immediately after a large number of sheets are passed through the first time, there is almost no remaining power in the power storage device, but the heating member is sufficiently warmed so that AC power is used. Afford. The above-described operation may be performed when charging is performed at the time of the second continuous sheet passing.

Further, even during the charging of the auxiliary power supply device 3 during continuous paper feeding, the auxiliary power supply device 3 may be switched so as to supply power to the auxiliary heat generating member 1b. This corresponds to a case where the detected fixing member temperature has fallen below a predetermined value. Of course, the power supply from the main power supply device 2 may be used instead of the power supply from the auxiliary heat generating member 1b. FIG. 10 is a timing chart showing another example of the fixing member temperature, AC power supply, DC power supply, and DC charge from the start-up start to the end of paper passing. After the temperature rise of the fixing member 14 is started, the control unit 60 ends the power supply from the auxiliary power supply device 3 to the heating unit, and then supplies power from the auxiliary power supply device 3 to the auxiliary heat generating member 1b during continuous paper feeding ( Before starting Z) in the figure, even if power is being supplied from the main power supply 2 to the heating unit 1 (specifically, the main heating member 1a), the auxiliary power supply via the main power supply 2 by the external power supply 3 is charged (Y 'in the figure).

1 is a schematic cross-sectional view of an overall configuration of an image forming apparatus using a fixing device according to the present invention. 1 is a cross-sectional configuration diagram of a fixing device that can be an object of the present invention. FIG. 2 is a block diagram schematically showing the circuit configuration of the fixing device of FIG. Relationship between usage pattern of main power supply and auxiliary power supply and heating time The figure for demonstrating the example which can implement | achieve the high-speed machine which does not have the temperature fall of the fixing member using a thin roller, and can raise a high speed. The figure which shows the relationship of the heating member temperature change in one Example of this invention, the power supply to a heating part, etc. AC power supply flow chart at startup DC charge / discharge flow chart at startup Timing chart showing an example of fixing member temperature, AC power supply, DC power supply, and DC charge from start-up to the end of paper feeding Timing chart showing other examples of fixing member temperature, AC power supply, DC power supply, and DC charge from start-up to end of paper feeding

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating part 1a Main heat generating member 1b Auxiliary heat generating member 2 Main power supply device 3 Auxiliary power supply device 4 Charger 5 Charge / discharge switching means 6a Main power control means 6b Auxiliary power control means 8 Fixing temperature detection means 10 Fixing device 14 Fixing member 15 Addition Pressure member 41 Photoconductor 42 Charging device 43 Mirror 44 Developing device 46 Cleaning device 47 Transfer portion 48 Transfer device 49 Registration roller 60 Control means 110 Paper feed roller 150 Exposure portion Lb Exposure light P Recording material T Fixing member temperature T0 Predeterminable fixing temperature Target temperature

Claims (7)

In a fixing device including a heating unit and a fixing member heated by the heating unit, and fixing a toner image on a recording medium by heating the fixing member.
A main power supply connected to an external power supply to supply power to the heating unit;
A power storage device that is charged by the external power source and supplies power to the heating unit at the time of temperature rise of the fixing member and a sheet passing operation ;
Provided and the ambient temperature detecting means for detecting the environmental temperature, and
Even if there is fed instruction after top temperature elevation before Symbol fixing member, when the temperature where the environmental temperature detecting unit detects is lower than a predetermined value,
Charging the power storage device from the external power source after the temperature rise of the fixing member and before starting the sheet passing operation based on the sheet passing instruction ;
A fixing device. The fixing device according to claim 1,
When the temperature where the environmental temperature detecting means has detected the predetermined value or more, without charging the power storage device after the above temperature elevation of the fixing member, to start the paper feeding operation by the paper feed instruction A fixing device characterized by the above. The fixing device according to claim 1 or 2, wherein the power storage device, when they are power supplied to the heating unit from the main power source device, a fixing device comprising a benzalkonium be power supplied to the heating unit . The fixing device as claimed in any one of claims 1 to 3, the charging from the external power supply to the power storage device, fixing the voltage of the electrical storage device is characterized in that the stop when a predetermined voltage apparatus. The fixing device according to claim 1, any one of 4, the electric storage device fixing device, characterized in that the electric double layer capacitor. An image forming unit, an image forming apparatus comprising the fixing device according to any one of claims 1 to 5. A main power supply;
A fixing device to which power is supplied from the main power supply device ;
An auxiliary power supply device having a power storage device that is charged by the main power supply device and supplies electric power to the fixing device at least when the temperature of the fixing device rises and during a sheet passing operation;
In an image forming apparatus comprising :
Even when there is a paper passing command after the temperature rise of the fixing device, if the temperature detected by the environmental temperature detection means is lower than a predetermined value, the temperature is passed after the temperature of the fixing device is raised. Charging the power storage device from the main power supply device before the paper feeding operation by the paper command is started ;
An image forming apparatus.