JP2006251323A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of quickly and surely warming an image carrier or the like and canceling a disfigured image. <P>SOLUTION: The image forming apparatus is provided with the image carrier 41 for carrying a document image, a heating element 31 for heating the image carrier 41, a fixing device 10, and a heating element 1 for the fixing device 10. At least one of the heaters 31 controls power supply to the heating element 1 of the fixing device 10 to which power is supplied from a battery device 3 charged by an external power source 2 and power supply to the heater 31 of the image carrier 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer using an electrophotographic system.

In order to increase the life of photoconductors that use electrophotographic systems such as copying machines and printers, a hard protective layer is provided on the organic photosensitive layer to increase durability. Yes.

  Conventionally, it has been known that discharge products and transfer paper components adhere to the surface of the photoconductor, and these adhere to the photoconductor and reduce its resistance when it absorbs moisture. It is known.

  Conventional organic photoconductors and the like do not generate abnormal images such as image flow because the adhering material is removed as the photoconductor wears due to friction with the cleaning blade and developer during operation.

  A highly durable photoconductor with a reduced amount of wear is less likely to cause deposits such as discharge products to be scraped off, and abnormal images such as image flow are likely to occur. The above image flow is eliminated by dehumidifying the moisture absorbed by warming the photoreceptor.

  In the conventional example, a method of mounting a planar heater inside the photosensitive element tube is widely used, and a method of using a fixing device as a heat source (see, for example, Patent Document 1 and Patent Document 2), A method of applying warm air (see, for example, Patent Document 3 and Patent Document 4) has been proposed.

Japanese Patent Laid-Open No. 6-130771 JP-A-10-254330 JP-A-5-257359 JP-A-6-19246

  However, in order to eliminate the image flow, the photosensitive member must be sufficiently warmed up, and time or electric power is required. However, since power is also required for starting up the fixing device at the start-up of the copying machine, etc. Electricity tends to be insufficient to warm up the body sufficiently in a short time. In particular, when the discharge product adheres and absorbs moisture, the image flow cannot be resolved unless it is heated considerably.

  The present invention has been made paying attention to the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of reliably heating an image carrier or the like in a short time and eliminating an image flow. It is in.

  In order to solve the above-described problem, an image forming apparatus according to claim 1 includes an image carrier that carries a document image and a heating element that heats the image carrier, and at least of the heating element. One is characterized in that power is supplied from a power storage device charged by an external power source.

  According to a second aspect of the present invention, there is provided a fixing device for fixing the toner image transferred onto the recording member by the image carrier to the recording member according to the first aspect of the invention. The apparatus further includes a heating element that heats the apparatus and at least one of which is supplied with power from the power storage device, and a control unit that controls power supply to the heating element of the fixing device and the heating element of the image carrier. It is characterized by that.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the control unit supplies power to the heating element of the image carrier when the image forming apparatus is activated. When the temperature of the fixing device is lowered during operation of the image forming apparatus, the power supply is selectively switched so as to supply power to the heating element of the fixing device.

  According to the image forming apparatus of the present invention, it is possible to reliably warm the image carrier or the like in a short time and eliminate the image flow.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a cross section of the image forming apparatus. Reference numeral 41 is an example of an image carrier made of a rotating body, and shows a drum-shaped photoconductor. The photoconductor 41 is OPC having a protective layer harder than the charge transport layer (CTL) on the outermost surface and having a diameter of 100 mm, a length of 360 mm, and a tube thickness of 1 mm. Around the photoreceptor 41, as a recording device P, a charging device 42 made of scorotron, a mirror 43 constituting a part of the exposure means, a developing means 44 having a developing roller 44a, in the order of rotation indicated by arrows. A transfer device 48 for transferring the developed image onto the transfer paper, a cleaning means 46 provided with a blade 46 a slidably contacting the peripheral surface of the photoconductor 41, and the like are disposed. The exposure light Lb is scanned on the photosensitive member 41 via the mirror 43 between the charging device 42 and the developing roller 44a. The irradiation position of the exposure light Lb is called an exposure unit 150. The transfer device 48 faces the lower surface of the photoconductor 41. The facing portion is a transfer portion 47, and a transfer device 48 is provided in the transfer portion 47.

  A pair of registration rollers 49 is provided at a position further upstream of the transfer unit 47. A recording member 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. The fixing device 10 is disposed further downstream from the transfer unit 47.

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

  On the other hand, feeding of the recording member P on the paper feed tray is started by the paper feed roller 110, temporarily stops at the position of the pair of registration rollers 49 through the transport path indicated by the broken line, and the toner image on the photoconductor 41 and the transfer are transferred. The timing of delivery is waited so as to match at the unit 47. When such a suitable timing arrives, the recording member P stopped on the registration roller 49 is sent out from the registration roller 49 and conveyed toward the transfer unit 47.

  The toner image on the photoconductor 41 and the recording member P coincide with each other at the transfer portion 47, and the toner image is transferred onto the recording member P by the electric field generated by the transfer member 48.

  In this way, the recording member P carrying the toner image in the image forming portion around the photoreceptor 41 is sent out toward the fixing device 10. While passing through the fixing device 10, the toner image on the recording member P is fixed to the recording member P and discharged to a paper discharge section (not shown).

  On the other hand, the residual toner remaining on the photosensitive member 41 without being transferred by the transfer unit 47 reaches the cleaning device 46 along with the rotation of the photosensitive member 41 and is cleaned while passing through the cleaning device 46 to prepare for the next image formation. It is done.

  Next, the power supply system will be described.

  The main power supply device 2 that supplies power to the image forming apparatus obtains power from a commercial power source and supplies power to the units of each part of the image forming apparatus. The auxiliary power supply device 3 has an electric double layer capacitor and the like, and is configured to be able to 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, thereby forming a large amount of power. The device can be powered. Not only the electric double layer capacitor but also a secondary battery such as Li ion or nickel metal hydride or a pseudo-capacitance capacitor using oxidation / reduction may be used.

  Next, the control system will be described.

  A sheet heater 31 is close to the inner side of the photoconductor 41, and control for controlling power supplied from the auxiliary power supply 3 to the sheet heater 31 in accordance with temperature information from the photoconductor temperature detection means 32. Means 60 are provided. The photoconductor temperature detection unit 32 includes a thermistor, a thermocouple, an infrared temperature detection device, and the like, and sends temperature information to the control unit 60. The control means 60 can perform control such as starting / stopping and increasing / decreasing the power supply to the planar heater 31 based on the obtained temperature information.

  Next, the capacitor auxiliary power supply 3 will be described in more detail.

  The auxiliary power supply device 3 is formed by connecting a plurality of capacitor cells composed of electric double layer capacitors, and it is desired that the power stored by charging from the main power supply device 2 be supplied more at the time of start-up or continuous paper feeding. In such a configuration, power exceeding the power supplied from the main power supply device 51 can be supplied to the image forming apparatus.

  The auxiliary power supply 3 as a configuration example has a module of 100 V by connecting in series 40 capacitor cells of 2.5v800F, Φ35 having an internal resistance of 5 mΩ or less and a length of about 120 mm. 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). In addition, since the internal resistance is 5 mΩ or less, the voltage across the terminals of the auxiliary power supply can be reduced less than a secondary battery such as a lithium battery or a nickel metal hydride battery even at a large current exceeding 20 A at startup. Moreover, since it is a small value among capacitors, a large amount of 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 an electric double layer capacitor that is a large-capacity capacitor is used in this configuration example. Unlike the secondary battery, the electric double layer capacitor has the following excellent characteristics because it does not involve a chemical reaction.

  In the auxiliary power source using a nickel-cadmium battery as a secondary battery, it takes several tens of minutes to several hours even if rapid charging is performed. It could only be realized once and was not practical. On the other hand, an auxiliary power supply using a capacitor can be charged quickly for several tens of seconds to several minutes, charging time is short, and charging is performed when the main power supply has a margin without printing. The number of times of heating using the auxiliary power source can be increased to a practical number.

  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, has little deterioration due to repeated charge and discharge, and has a long life. In addition, unlike lead-acid batteries, there is no need for liquid replacement or replenishment, so almost no maintenance is required.

  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 being studied. 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 sufficient capacity for power supply for several seconds to several tens of seconds. Further, NEC has realized a capacitor of about 80 F under the trade name Hypercapacitor. Furthermore, JEOL has announced a technology called a nano-gate capacitor with a withstand voltage increased to 3.2 to 3.5 V and a power density of 50 to 75 wh / kg, which is 5 to 10 times the conventional one.

Next, an embodiment in which the above configuration is further embodied will be described.
(Example 1)
The planar heater 31 inside the photosensitive drum 41 has a rating of 100V300W. When the main power is turned on at the time of starting up the image forming apparatus, almost the full power is consumed for energizing the fixing device. Electric power for heating the photosensitive drum 41 is not supplied from the main power supply but from the capacitor auxiliary power supply 3 charged before the start-up.

  FIG. 2 is a circuit configuration diagram thereof. The planar heater 31 is heated by the electric power of the capacitor auxiliary power supply 3, and the contact point 7 is on / off controlled by the control unit (control unit) 60 until the photosensitive member temperature detection unit 32 reaches 45 ° C. Since the 300 W heater can be heated, the photosensitive drum 41 can be heated to a predetermined temperature in a short time.

As another embodiment, as shown in FIG. 3, a planar heater 31 adjacent to the photosensitive drum 41 is replaced with a 100 V 50 W planar AC heater 31 a for main power and a 100 V 250 W planar DC heater 31 b for auxiliary power. It may be provided separately. In this case, even if the capacitor auxiliary power source 3 cannot be charged, it can be heated by the main power source heater 31a.
(Example 2)
The fixing device 10 in FIG. 1 has an AC heater 1a by the main power source 2 and a DC heater 1b to which power is supplied from the auxiliary power device 3 as shown in the detailed fixing diagram in FIG. Control means 60 for controlling the power supplied from the auxiliary power supply device 3 to the fixing device 10 according to the temperature information from the fixing portion temperature detecting means 8 is provided. The fixing unit temperature detection unit 8 includes a thermistor, a thermocouple, an infrared temperature detection device, and the like, and sends temperature information to the control unit 60. The control means 60 performs the control such as starting / stopping and increasing / decreasing the power supply to the heating means 1 of the fixing device 10 based on the obtained temperature information, and at the same time, the temperature obtained from the photoconductor temperature detecting means 32. Power supply control to the planar heater 31 can also be performed based on the information.

  The auxiliary power supply device 3 in the fixing device 10 is used as auxiliary power for starting up fixing in a short time, and auxiliary power for preventing a fixing roller temperature from being lowered during paper passing and causing a fixing failure. .

FIG. 5 shows an example of a circuit that controls the temperature of the photoconductor 41 and the fixing device 10 with one auxiliary power supply device 3. Since the temperature of the photoconductor 41 and the fixing device 10 can be controlled by one auxiliary power supply device 3, there are advantages in cost and installation space.
(Example 3)
When the image forming apparatus is started up, the auxiliary power supply 3 supplies power only to the surface heater 31 of the photoconductor, and heats the photoconductor 41 in a short time. The fixing device 10 heats the fixing roller with an AC heater of a main power source. During operation of the image forming apparatus, the temperature of the fixing device and the like in the apparatus increases, and the photosensitive drum 41 can also maintain a predetermined temperature. Therefore, it is not necessary to supply power from the auxiliary power supply 3 to the photosensitive sheet heater 31. It becomes. Since the temperature of the fixing roller is likely to decrease during operation, the auxiliary power supply device 3 is controlled by the control unit 60 so as to supply power to the DC heater of the fixing device 10.

  Although the embodiments have been described with respect to the OPC drum having the protective layer, the present invention is not limited thereto, and is effective for an OPC drum having no protective layer and a belt photoreceptor. An amorphous silicone photoreceptor is also effective.

  As described above, in the image forming apparatus according to the present embodiment, by using the heater 31 supplied with power from at least the auxiliary power source 3 of the power storage device, the photosensitive member 41 is reliably warmed in a short time and the image flow is eliminated. can do.

  In the image forming apparatus of the present embodiment, power is supplied from the auxiliary power source 3 of the power storage device to the heater 31 of the photoconductor 41 and the heaters 1 a and 1 b of the fixing device 10. It can be used, resulting in cost and installation space advantages.

  In the image forming apparatus of the present embodiment, when power is supplied by switching from the auxiliary power source of the power storage device to the heater 31 of the photoconductor 41 and the heater 1 of the fixing device 10, the supply destination is divided between startup and operation. Thus, it is possible to efficiently supply power to the heaters 1 and 31.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a circuit configuration diagram of a power supply system of a main part of the image forming apparatus of FIG. 1. It is a figure which shows one Example of the circuit structure of a power supply system. FIG. 2 is a configuration diagram of a fixing device of the image forming apparatus in FIG. 1. It is a figure which shows the other Example of the circuit structure of a power supply system.

Explanation of symbols

1 Heater (heating element)
2 Main power supply (external power supply)
3 Auxiliary power supply (power storage device)
10 Fixing device 31 Planar heater (heating element)
41 photoconductor (image carrier)
60 Control means

Claims (3)

  An image carrier that carries a document image and a heat generator for heating the image carrier, and at least one of the heat generators is supplied with power from a power storage device charged by an external power source. Image forming apparatus.   A fixing device that fixes the toner image transferred onto the recording member by the image carrier to the recording member; a heating element that heats the fixing device and at least one of which is powered by the power storage device; The image forming apparatus according to claim 1, further comprising a control unit that controls power supply to a heating element of the fixing device and a heating element of the image carrier. The control means supplies power to the heating element of the image carrier when the image forming apparatus starts up, and supplies power to the heating element of the fixing device when the temperature of the fixing device decreases during operation of the image forming apparatus. The image forming apparatus according to claim 2, wherein the power supply is selectively switched as described above.

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