JP4585758B2 - Heating device - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device such as a fixing device that fixes a toner image of an image forming apparatus such as a copying machine, a printer device, or a facsimile device using an electrophotographic method onto a recording sheet, and more particularly to efficiency improvement of power saving. is there.

  An image forming apparatus such as a copying machine or a printer forms an image on a recording medium such as plain paper or OHP. This image forming apparatus employs an electrophotographic system in view of high speed image formation, image quality, cost, and the like. The electrophotographic method is a method in which a toner image is formed on a recording medium, and the formed toner image is fixed on the recording medium with heat and pressure. The heat roller method is currently the most widely used fixing method from the standpoint of safety. Has been. In the heat roller system, a heat roller heated by a heat generating member such as a halogen heater and a pressure roller disposed opposite to the heat roller are pressed to form a mutual pressure contact portion called a nip portion, and a toner image is formed in the nip portion. This is a method of heating through a recording medium to which is transferred.

  In recent years, environmental problems have become important and image forming apparatuses such as copiers and printers have been saving energy. In considering the energy saving of this image forming apparatus, what cannot be ignored is the power saving of the fixing device for fixing the toner to the recording medium. In order to reduce the power consumption of the fixing device during standby of the image forming apparatus, the temperature of the heating roller is maintained at a constant temperature slightly lower than the fixing temperature during standby, so that the temperature can be immediately raised to a usable temperature during use. The temperature of the fixing roller is not waited for. In this case, extra energy is consumed by supplying a certain amount of power even when the fixing device is not used.

  It is desired to reduce power consumption during standby and to further reduce power consumption, and there is a demand for zero power supply when not in use. However, if energy consumption is reduced to zero during standby, the heating roller mainly uses a metal roller such as iron or aluminum and has a large heat capacity. Therefore, it takes several minutes to 10 minutes to raise the temperature to a usable temperature of about 180 ° C. A long heating time such as several minutes is required, and the convenience for the user is deteriorated. In order to shorten the heating time of the heating roller, it is preferable to increase the input energy per unit time, that is, the rated power. In fact, many high-speed machines with high printing speeds are compatible with a power supply voltage of 200V. However, in a general office in Japan, the commercial power supply is 100V15A, and in order to make it compatible with 200V, it is necessary to carry out a special work related to the power supply at the installation location, so it cannot be said that it is a general solution. Therefore, even if the temperature of the heating roller is increased in a short time, the maximum input energy is determined by the power source.

In order to improve this, as disclosed in Patent Document 1, for example, when the fixing device is in a standby state, a voltage lower by a certain level is supplied to the heating roller to delay the temperature of the fixing device from decreasing. As shown in Patent Document 2, a secondary battery as an auxiliary power supply is charged during standby of the fixing device, and when the fixing device is started up, power is supplied from the main power supply device and the secondary battery or the primary battery. I try to save time.
Japanese Patent Laid-Open No. 10-10913 Japanese Patent Laid-Open No. 10-282821

  However, since the fixing device disclosed in Patent Document 1 supplies a voltage that is lower by a certain level to the fixing device even during standby, it cannot be said to be sufficient power saving. Moreover, the maximum supply power at the time of start-up is not mainly intended to be higher than the power supplied from the main power supply device. The fixing device disclosed in Patent Document 2 supplies power from a main power supply device and a secondary battery or a primary battery at the time of start-up. As a secondary power supply, a CADNICA battery or a lead storage battery is generally used. The secondary battery has the property that the capacity deteriorates and decreases as the battery is repeatedly charged and discharged, and the life is shorter as the battery is discharged at a higher current. In general, a CADNICA battery, which has a long current with a large current, has a charge / discharge cycle of about 500 times. If the battery is charged / discharged 20 times a day, the battery life will be reached in about one month. In other words, it takes a lot of time to replace the battery, and the running cost such as the replacement battery cost is very high. Furthermore, lead acid batteries are not preferred for office equipment, such as using liquid sulfuric acid.

  In addition, due to the structure of the halogen heater used for the heating roller, a large inrush current flows at the moment of lighting, and a current close to 7 to 10 times the rated current may flow depending on the impedance of the power source. As can be seen from the fact that there is data that the lifetime decreases as much as 80% when the current increases by 10%, it is not preferable that an excessive current flows through the heater even at the moment. Similarly, inrush current flows in the peripheral circuits as well, and there are concerns about adverse effects, and special measures may need to be taken.

  It is an object of the present invention to provide a heating apparatus that can improve such disadvantages, enhance the power saving effect, and shorten the rise time.

Heating apparatus according to the present invention includes a main power supply for heating by supplying electric power to the fixing device of the image forming apparatus an auxiliary power supply, the main power supply is connected to an outlet supplying a commercial power, the auxiliary power supply can be charged in a few minutes, and having a capacitor having a capacitance for supplying power of a few tens of seconds, the time of heating operation of the fixing device, the main power supply and the auxiliary power unit the power subjected fed from both the fixing device, when not supplying power to the fixing device, characterized by charging the capacitor of the auxiliary power unit in front Symbol main power supply. It is desirable to use an electric double layer capacitor as the capacitor constituting the auxiliary power supply device.

The fixing device has a halogen heater, when supplying power to the fixing device, and connect the main power supply to the fixing device at a predetermined timing after supplying electric power to the fixing device from the main power supply auxiliary power supply connect the apparatus to a fixing device and supplies power to the fixing device from the auxiliary power supply, and connect the auxiliary power supply to the fixing device at a predetermined timing after supplying electric power to the fixing device from the auxiliary power unit it is desirable to supply power to the fixing device from the main power supply and connect the main power supply to the fixing device.

For example, when power is not supplied to the fixing device from the main power supply device in a standby state, the capacitor of the auxiliary power supply device is charged by the main power supply device , and power is supplied from the main power supply device to the fixing device during the heating operation of the fixing device. supplies to supply power to be fixing device from the capacitor of the auxiliary power unit, a large amount of electric power to the fixing device can be supplied, it can be started up to a predetermined temperature in a short time of the fixing device.

In addition, by using an electric double layer capacitor as an auxiliary power supply device, for example, when power is not supplied from the main power supply device in the standby state to the fixing device, it can be charged in a short time, and reliable during the heating operation of the fixing device. In addition, power can be supplied from the auxiliary power supply device, and it has a long life and little deterioration due to repeated charge and discharge, and can be used stably for a long period of time without maintenance.

Further, when supplying power to the fixing device, by shifting the timing of power application from the power-up and auxiliary power supply from the main power supply, the heater life is shortened a making current to the heater of the fixing device by reducing such Can be prevented and can be used stably for a long time.

  FIG. 1 is a block diagram showing the configuration of the present invention. As shown in the figure, the heating device 1 includes a heating unit 2, a main power supply device 3, an auxiliary power supply device 4, and a switching device 5. For example, as shown in FIG. 2, the heating unit 2 includes a heating roller 6 and a pressure roller 7, and heats a toner image transferred to a recording medium by an image forming apparatus such as an electrophotographic copying machine or a printer. , And a fixing device for pressurizing and fixing the recording medium. The heating roller 6 of the heating unit 2 incorporates a heater such as a halogen heater, and generates heat by power supplied from the main power supply device 3 and the auxiliary power supply device 4. The main power supply 3 is connected to an outlet provided at a setting place of the image forming apparatus, and has functions such as voltage adjustment according to the heating unit 2 and AC and DC rectification. The auxiliary power supply 4 has a chargeable / dischargeable capacitor. The capacitor of the auxiliary power supply 4 has a capacitance of about 2000 F, such as an electric double layer capacitor developed by Nippon Chemi-Con Co., Ltd., and has a capacity sufficient for power supply for several seconds to several tens of seconds. It has. The switching device 5 supplies or cuts off power from the main power supply device 3 and the auxiliary power supply device 4 to the heating unit 2 and supplies power from the main power supply device 3 to the auxiliary power supply device 4 to charge the capacitor of the auxiliary power supply device 4. .

  The operation when the heating device 1 configured as described above heats the heating unit 2 such as the fixing device will be described with reference to the waveform diagram showing the power supply amount of FIG.

  When the operation of the heating device 1 is started, the switching device 5 connects the main power supply device 3 to the heating unit 2, supplies predetermined power from the main power supply device 3 to the heating unit 2, and sets the heating roller 6 of the heating unit 2. Heat to a predetermined temperature. The toner image is fixed by the heating unit 2 heated to the predetermined temperature, and when in a standby state, the switching device 5 cuts off the connection between the main power supply 3 and the heating unit 2, and the main power supply 3 is connected to the auxiliary power supply 4. To charge the capacitor of the auxiliary power supply 4. When starting up the heating unit 2 from this standby state, the switching device 5 connects the main power supply device 3 and the heating unit 2 to supply electric power from the main power supply device 3 to the heating unit 2 and to turn the auxiliary power supply device 4 into the heating unit. 2 to supply power to the heating unit 2 also from the auxiliary power supply device 4. As described above, since the power is supplied from both the main power supply device 3 and the auxiliary power supply device 4 when starting up the heating unit 2 from the standby state, a large amount of power can be supplied to the heating unit 2. The temperature can be raised to a predetermined temperature in a short time.

  Further, unlike the secondary battery, the capacitor included in the auxiliary power supply device 4 does not involve a chemical reaction, and thus has the following excellent characteristics. In other words, an auxiliary power supply device using a general nickel-cadmium battery as a secondary battery has several hours even if quick charging is performed, but the auxiliary power supply device 4 using a capacitor has a rapid charge of about several minutes. Therefore, when the standby state and the heating state are repeated within the same time, it is possible to reliably supply power from the auxiliary power supply device 4 at startup by using the auxiliary power supply device 4 using a capacitor. The heating unit 2 can be raised to a predetermined temperature in a short time.

  In addition, since the nickel-cadmium battery has 500 to 1000 charge / discharge cycles, it has a short life as an auxiliary power supply device for heating, and it takes time and labor to replace the auxiliary power supply device 4 using a capacitor. Has a long life, little deterioration due to repeated charging and discharging, and further, since there is no need for liquid replacement or replenishment unlike lead-acid batteries, it can be used stably with little maintenance.

  In the above description, when the heating unit 2 is started from the standby state, the case where power is simultaneously supplied to the heating unit 2 from the main power supply device 3 and the auxiliary power supply device 4 has been described. However, the halogen heater is applied to the heating roller 6 of the heating unit 2. 4 is used, as shown in the waveform diagram of FIG. 4, the auxiliary power supply device 4 is connected to the heating unit 2 at a certain timing T after the supply of power from the main power supply device 3 to the heating unit 2 is started. Then, electric power is supplied from the auxiliary power supply 4 to the heating unit 2. In other words, the halogen heater generates an inrush current when the power is turned on due to the characteristics, and affects the damage to the circuit and the life of the heater itself. If the power of the auxiliary power supply 4 in addition to the main power supply 3 is also supplied to the halogen heater at the same time, the inrush current of the halogen heater increases, and there is a concern that the life of the halogen heater etc. may be reduced and adversely affect the circuit. It is necessary to apply. On the other hand, the supply current of the halogen heater is reduced by supplying power from the auxiliary power supply device 4 to the heating unit 2 at a certain timing T after the supply of power from the main power supply device 3 to the heating unit 2 is started. This prevents failures such as shortening the heater life. It should be noted that the power supply from the auxiliary power supply device 4 may be made faster than the power supply from the main power supply device 3 by a fixed timing.

It is a block diagram which shows the structure of the Example of this invention. It is a block diagram of a heating part. It is a wave form diagram which shows the electric power supply amount of the said Example. It is a wave form diagram which shows the other electric power supply amount of the said Example.

Explanation of symbols

1; heating device, 2; heating unit, 3; main power supply device, 4; auxiliary power supply device,
5; switching device, 6; heating roller, 7; pressure roller.

Claims (4)

Has a main power supply and an auxiliary power supply apparatus for heating by supplying electric power to the fixing device of an image forming apparatus, the main power supply is connected to an outlet supplying a commercial power, the auxiliary power unit, the charge in minutes possible, and having a capacitor having a capacitance for supplying power of a few tens of seconds, the time of heating operation of the fixing device, power to the fixing device from both the main power supply and the auxiliary power unit test paper, and when from the main power supply does not supply power to the fixing device, a heating apparatus characterized by charging the capacitor of the auxiliary power unit in front Symbol main power supply.   The heating apparatus according to claim 1, wherein the capacitor constituting the auxiliary power supply device is an electric double layer capacitor. The fixing device has a halogen heater, the fixing device when powering the certain timing after supplying electric power to the fixing device the main power supply from the main power supply connected to said fixing device heating apparatus according to claim 1, wherein supplying power to the fixing device from the auxiliary power unit by connecting the auxiliary power unit to the fixing device at a. The fixing device has a halogen heater, the fixing device when powering the constant timing the auxiliary power supply from supplying electric power to the fixing device from the auxiliary power unit connected to said fixing device heating apparatus according to claim 1, wherein supplying power to the main power supply to the fixing unit from the main power supply connected to the fixing device at a.

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