JP2002280146A - Heating device, fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device using a large capacity capacitor as an auxiliary power source capable of appropriately selecting charge or discharge of the capacitor, and a fixing device and an image-forming device using the same. SOLUTION: This heating device includes a heating part 1 for heating a matter to be heated, heat generating bodies 1a, 1b raising temperature of the heating body 1, and a power supply means for supplying power to the heat generating bodies. The power supply means includes a main power source 2 from a commercial power source and the auxiliary power source 3 from the capacitor. A selecting means 5 selecting a charging mode connecting the capacitor to a charging circuit or a discharging mode connecting the capacitor to a discharging circuit connected to the heat generating body 1a is provided. Detecting means 9a, 9b detecting a state of the device is provided and the charging mode of the capacitor or the discharging mode of the capacitor is selected according to a value detected by the detecting means 9a, 9b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, and the like, a fixing device used in the image forming apparatus, and a heating device for a recording medium such as paper and film suitable for the fixing device. Things.

[0002]

2. Description of the Related Art Copiers, printers, facsimile machines and the like have a process of forming and recording an image on a recording medium such as plain paper or a film for an overhead projector (hereinafter referred to as "OHP"). Various image forming and recording methods have been realized, and among them, the electrophotographic method is widely used in image forming apparatuses because of its high speed, image quality, cost, and the like. 2. Description of the Related Art In an electrophotographic image forming apparatus, there is a fixing step in which an unfixed toner image is formed on a recording medium such as paper or film and fixed by heat and pressure. As a fixing method, a heat roller method is currently most frequently employed in terms of high speed, safety, and the like.

In the heat roller system, a heating roller heated by a heat-generating member such as a halogen heater and a pressure roller disposed opposite to the heating roller are pressed against each other to form a mutual pressing portion called a nip portion. In this method, a sheet-shaped recording medium on which an unfixed toner image has been formed is passed through the nip portion and heated. The heating roller mainly uses a metal roller such as iron or aluminum and has a large heat capacity. For this reason, there is a disadvantage that a long startup time of several minutes to several tens of minutes is required to raise the temperature to about 180 ° C., which is the usable temperature.

Therefore, in an image forming apparatus such as a copying machine,
Even during a standby time when the user does not perform printing, power is supplied to the heating roller to maintain the temperature at a preheating temperature slightly lower than the usable temperature, so that the temperature immediately rises to the usable temperature. This is to prevent the user from waiting for the temperature of the fixing roller to rise, and extra energy that does not contribute to image formation is consumed even during standby without using the device. In addition, there is a research result that this standby energy consumption is about 70 to 80% of the energy consumption of the device.

[0005] In recent years, laws and regulations for power saving and energy saving have been enacted in various countries due to increasing awareness of environmental protection. In order to save power in the image forming apparatus, it is effective to reduce the standby energy consumption, which is a large percentage, so that it is desirable to reduce the power supply to zero when not in use.

However, if the standby power is reduced to zero in the configuration of the conventional image forming apparatus, it takes time to raise the temperature of the fixing roller to a predetermined temperature at the time of reuse, so that the waiting time becomes longer. The usability of the device will deteriorate. For this reason, a configuration for rapidly increasing the temperature of the heating roller is required.

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, some high-speed machines with a high printing speed are compatible with a power supply voltage of 200V. However, in a typical office in Japan, the power supply is generally 100V15A and the upper limit is 1500W.
In order to support 00V, it is necessary to perform special work on the power supply related to the installation location of the device, and this is not a general solution. For this reason, even if it is going to raise the temperature of the heating roller in a short time, the upper limit of the input energy cannot be increased.

In order to improve this, it has been proposed to solve the above-mentioned problem by using an auxiliary power supply. In this proposal, a secondary battery is used as a chargeable auxiliary power source. Typical secondary batteries are lead storage batteries and CADNICA batteries. For example, Japanese Patent Laying-Open No. 05-232839 proposes to have an auxiliary power supply in addition to a main power supply. The power of the main power supply for heating the fixing roller is not further increased by the auxiliary power supply, but the power is supplied from the auxiliary power supply to the heating element of another system.

Japanese Patent Laid-Open Publication No. 10-010913 proposes to provide an energy-saving fixing device using an auxiliary power supply in addition to a main power supply. However, two levels of power are supplied from a single power supply, and the main purpose is not to increase the maximum supply power by using an auxiliary power supply than when only the main power supply is used. Japanese Patent Application Laid-Open No. 10-282821 proposes providing various functions using an auxiliary power supply in addition to a main power supply. However, a secondary battery, a primary battery, or the like is used as an auxiliary power supply.

In Japanese Patent Application Laid-Open No. 2000-075737, an image forming apparatus provided with a commercial power supply and a storage battery is provided with a function of reducing productivity during charging of the storage battery, a loading determination unit for the storage battery, and a monitoring of the charge capacity. It has been proposed to reduce productivity depending on the result of monitoring. Further, since a storage battery is used and the charging time is long, it is described that the battery is charged externally or charged at night.

There are the following problems in those using a secondary battery. A secondary battery has the property that when it is repeatedly charged and discharged a number of times, it deteriorates and its capacity decreases, and the longer it discharges with a large current, the shorter its life. Even in the case of CADNICA batteries, which are generally considered to have a long life at a large current, the number of charge / discharge repetitions is about 500 to 1000 times, and if the charge / discharge is repeated 20 times a day, the battery life is about one month. Will run out. Therefore, it takes time to replace the battery, and the running cost such as the battery cost is very high. Furthermore, since charging takes a long time, it is necessary to charge at night or take it out of the device and charge it. -Discharge is little by little, and it is difficult to extract large power in a short time. -If charging is continued when there is no need to discharge, gas will be generated, which may cause a failure and is not safe. -In the case of a lead storage battery, liquid sulfuric acid is used, which is not preferable for office equipment. Therefore, it is practically difficult to use a secondary battery.

Therefore, the present inventors, as shown below,
The use of a large capacity capacitor such as an electric double layer capacitor as an auxiliary power source was studied. Large capacity capacitors
The number of charge / discharge repetitions is almost unlimited, there is almost no deterioration in charging characteristics, and regular maintenance is unnecessary. In addition, the charging time of a battery as a secondary battery requires several hours, whereas the large-capacity capacitor has a characteristic that it can be reduced to several seconds to several tens of seconds. Further, since a large current of several tens to several hundreds of amps can flow in the electric double layer capacitor, power can be supplied in a short time. In addition, even if the battery is continuously charged, no gas is generated and the battery is safe.

When such a large-capacity capacitor is used as an auxiliary power supply, power exceeding the limit of the power of the commercial power supply is supplied in a short time of several seconds to several tens of seconds when the heating device, the fixing device, and the image forming device rise. Because you can
It should be possible to realize a heating device, a fixing device, and an image forming device that have a short rise time and high reliability and durability.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art, and the objects of the invention described in each claim are as follows. It is an object of the present invention to provide a heating device that uses a large-capacity capacitor as an auxiliary power supply, and that can appropriately switch charging and discharging of the capacitor. Another object of the present invention is to provide a heating device capable of appropriately performing switching timing of charging and discharging of a capacitor.

It is another object of the present invention to provide a heating device capable of appropriately controlling a discharge amount of a capacitor according to a situation. A fourth object of the present invention is to provide a heating device capable of shortening a start-up time by supplying a large amount of electric power for a short time when necessary. It is an object of the present invention to provide a heating device that can prevent an excessive rise in temperature of a heating unit by supplying the heating unit with a constant voltage depending on the situation.

According to a sixth aspect of the present invention, there is provided a fixing device in which a heating device using a large-capacity capacitor as an auxiliary power source is used as a heating device of a fixing device, wherein charging and discharging of the capacitor can be appropriately controlled. The purpose is to provide.

According to a seventh aspect of the present invention, there is provided an image forming apparatus having a fixing device using a large-capacity capacitor as an auxiliary power supply for a heating device, wherein the charge and discharge of the capacitor can be appropriately controlled. It is intended to provide a device. It is an object of the present invention to provide an image forming apparatus capable of reliably charging at the next start-up and shortening the start-up time.

[0018]

In order to achieve the above object, the present invention is configured as follows. The invention according to claim 1 includes a heating unit for heating the object to be heated, a heating unit for increasing the temperature of the heating unit, and power supply means for supplying power to the heating unit. The power supply means is a heating device having a main power supply composed of a commercial power supply and an auxiliary power supply composed of a capacitor. The power supply means includes a charging mode for connecting the capacitor to a charging circuit, and a discharge mode connected to the heating element. Switching means for switching to a discharge mode connected to a circuit is provided.

According to a second aspect of the present invention, in the first aspect of the present invention, a detecting means for detecting a state of the apparatus is provided, and the capacitor is switched to a charging mode or a discharging mode according to a value detected by the detecting means. It is characterized by the following. According to a third aspect of the present invention, in the second aspect, the discharge circuit includes a circuit including a constant voltage circuit and a circuit not including the constant voltage circuit.

According to a fourth aspect of the present invention, in the third aspect of the present invention, there is provided means for detecting a temperature of the heating section, and when the temperature of the heating section is lower than a predetermined temperature, the capacitor is discharged. The discharge is performed by a circuit not including a voltage circuit. The invention described in claim 5 is the third invention.
In the invention described in the above description, a means for detecting the temperature of the heating section is provided, and when the temperature of the heating section is discharged at a predetermined temperature or higher, the capacitor is discharged by a circuit including a constant voltage circuit.

According to a sixth aspect of the present invention, there is provided a heating device according to any one of the first to fifth aspects, wherein an unfixed image on a recording material as a member to be heated is heated, and the unfixed image is recorded on the recording material. The present invention relates to a fixing device characterized in that fixing is performed thereon.

According to a seventh aspect of the present invention, there is provided an image carrier, charging means for charging the surface of the image carrier, exposure means for exposing the charged surface of the image carrier to form an electrostatic latent image, Developing means for supplying toner to the surface of the image carrier to visualize the electrostatic latent image by a toner image; transfer means for transferring the toner image onto a recording material; and recording by heating the toner image on the recording material An image forming apparatus comprising a fixing unit for fixing on a material, wherein the fixing unit includes the fixing device according to claim 6 as the fixing unit.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, when the main power of the entire device is turned off, the capacitor is set to a fully charged state and then turned off.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a heating device, a fixing device, and an image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a circuit configuration of a heating device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a heating unit, 2 denotes a main power supply, 3 denotes an auxiliary power supply, 4 denotes a charger for the auxiliary power supply, and 5 denotes a charge / discharge switching unit. In this configuration example, the heating unit 1 has heating elements 1 a and 1 b, and the main heating element 1 that generates heat by electric power supplied from the main power supply 2.
a, and an auxiliary heating element 1b that generates heat by electric power supplied from the auxiliary power supply 3. The temperature of the heating unit 1 rises to heat an object to be heated such as paper or an OHP film (not shown). .

The main power supply 2 is a commercial power supply which can be taken in from an outlet provided at a place where a device such as a copying machine is installed. The main power supply 2 adjusts voltage according to the main heating element 1a and rectifies AC and DC. It may have a function.

The auxiliary power supply 3 is a chargeable / dischargeable device. In this configuration example, an electric double layer capacitor is used as a large capacity capacitor. Unlike a secondary battery, a capacitor does not involve a chemical reaction and has the following excellent characteristics.・ Charge time is short: Nickel which is common as a secondary battery
With an auxiliary power supply using a cadmium battery, it takes several hours to perform quick charging. On the other hand, an auxiliary power supply using a capacitor can rapidly charge for about several minutes, and therefore can be charged and discharged frequently. Can be increased.

Long life: The nickel-cadmium battery has a short life as an auxiliary power supply for heating because the number of charge / discharge cycles is 500 to 1000, and replacement time and cost are problematic. On the other hand, an auxiliary power supply using a capacitor has a life of an order of magnitude and is less likely to deteriorate due to repeated charging and discharging. Therefore, it is particularly advantageous for a heating device of a fixing device in an image forming apparatus in which a non-heating operation during standby and a heating operation during operation are repeated. In addition, there is no need for liquid exchange or replenishment as in the case of a lead storage battery, so that almost no maintenance is required.

High-power short-time discharge is possible: Since the secondary battery cannot discharge stored power at a stretch, the heating unit cannot supply high power when starting up from a low temperature, and the startup time can be shortened. Can not hope for a high effect. On the other hand, an auxiliary power supply using a capacitor can discharge a large amount of power in a few seconds, and is therefore effective in shortening the startup time.

High safety even if charging is continued: Since the secondary battery uses a chemical reaction, if it does not need to be discharged after charging to the maximum capacity, if the battery is kept connected to the charging circuit, The container may expand and rupture due to a gas due to the reaction. On the other hand, since the auxiliary power supply using the capacitor uses a physical phenomenon instead of a chemical reaction, there is no generation of gas, and it is safe to continue charging. Therefore, there is no need to provide a mode in the float state.

In recent years, capacitors capable of storing a large amount of electric energy have been developed, and their use in electric vehicles and the like is being studied. For example, an electric double layer capacitor or the like developed by Nippon Chemi-Con Corporation has a capacitance of about 2000F, and has a sufficient capacity for power supply for several seconds to several tens of seconds. Also, a capacitor of about 80F has been realized by NEC Corporation under the trade name "Hypercapacitor".

According to the embodiment shown in FIG. 1, the power supplied to the heating unit 1 can be supplied from the main power supply 2 to the main heating element 1a, and the auxiliary power supply 3 can be supplied to the auxiliary heating element 1b.
It can be supplied from As described above, by using the power from both the main power supply 2 and the auxiliary power supply 3, a large amount of power exceeding the maximum supply power from the main power supply 2 can be supplied to the heating unit 1 only for a predetermined time.

When the auxiliary power supply 3 composed of a capacitor or the like is not sufficiently charged, the auxiliary power supply 3 is charged via the charger 4 by supplying power from the main power supply 2 in a standby state where relatively little power is consumed. Keep it. Accordingly, when a large amount of electric power is required, for example, at the time of startup when the temperature of the fixing roller as a heating unit is to be rapidly increased from room temperature to the operating temperature, the electric power of the auxiliary power supply 3 together with the main power supply 2 is used for heating. By supplying a large amount of energy to the fixing unit, the temperature of the fixing roller can be raised in a short time, and by using a capacitor as the auxiliary power supply 3 of the heating device, it is possible to obtain effects that cannot be obtained with a secondary battery. it can. In order to control the temperature of the heating unit 1, the main power source 2
It may have a control means 6 for controlling the power to a. The control means 6 includes a switch and a control device such as a CPU.
Turns on / off the conduction from the main power supply 2 to the main heating element under the set conditions.
A configuration for realizing the off operation may be used.

As described above, the auxiliary power supply 3 using a capacitor does not generate gas or the like, and is safe to continue charging. Therefore, it is not necessary to provide a float mode. Therefore, the charging / discharging switching means 5 only needs to be able to switch between a charging circuit in which the capacitor as the auxiliary power supply 3 is connected to the charger 4 and a discharging circuit connected to the main heating element 1b.

FIG. 2 is a circuit diagram showing another embodiment of the heating device according to the present invention. This circuit configuration differs from the circuit configuration shown in FIG. 1 in that it has two detecting means 9a and 9b for detecting the state of the device. The detecting means 9a is a temperature sensor for detecting the temperature of the heating unit 1, and is composed of a thermistor, a thermocouple, or the like. The detecting means 9b is a voltmeter for detecting the amount of charge of the auxiliary power supply 3 composed of a capacitor. Unlike a battery, a capacitor has a characteristic that the voltage between terminals decreases as the capacitor is discharged. Therefore, the remaining power can be detected by measuring the voltage between terminals of the capacitor. Instead of the voltmeter, a timer for measuring the discharge time or time of the auxiliary power supply 3, a unit for notifying the start of heating such as a heating start button or a human sensor, a unit for detecting a heating operation state, or the like may be used. Good. These may be used alone, but the charge and discharge control of the auxiliary power supply 3 can be more appropriately performed by combining a plurality of them.

The operation of switching between the values detected by the detection means 9a and 9b and the charging and discharging of the auxiliary power supply 3 will be described below. In a device such as a copying machine, when the main power switch is turned on, or when a human sensor detects that a person is approaching the device body, power is supplied from the main power source 2 to the main heating element 1a. The auxiliary power supply 3 is connected to the auxiliary heating element 1b by the switching means 5 so that power can be supplied from the auxiliary power supply 3 to the auxiliary heating element 1b at the same time as the power is supplied. To form

Further, even when the temperature of the heating section 1 falls below a predetermined temperature during the heating operation, the switching means 5 causes the auxiliary power supply 3 to generate the auxiliary heat so that power can be supplied from the auxiliary power supply 3 to the auxiliary heating element 1b. The discharge circuit is formed by connecting to the body 1b. Alternatively, the switching means 5 switches the auxiliary power supply 3 to the charger 4 so that the auxiliary power supply 3 is charged at a preset time.
To form a charging circuit.

When the heating operation is not being performed, a switching circuit 5 connects the auxiliary power supply 3 to the charger 4 to form a charging circuit.
The auxiliary power supply 3 is charged from the main power supply 2 via the charger 4.
As a result of the detection by the detecting means 9a, when the charged amount of the auxiliary power supply 3 is equal to or less than a predetermined value, the switching means 5 connects the auxiliary power supply 3 to the charger 4 to form a charging circuit. When the discharge time of the auxiliary power supply 3 is equal to or more than a predetermined value and the operation is in the non-heating operation,
The auxiliary power supply 3 is connected to the charger 4 by the switching means 5 to form a charging circuit. The above is an example and is not limited to these.

FIG. 3 is a circuit diagram showing still another embodiment of the heating device according to the present invention. This circuit configuration is different from the circuit shown in FIG. 2 in that the discharge circuit of the auxiliary power supply 3 can be switched in two ways based on the detection information by the temperature detection means 9a for detecting the temperature of the heating unit 1. One of these two discharge circuits is provided with a constant voltage circuit, and the other of the discharge circuits is not provided with a constant voltage circuit, and is discharged directly from the auxiliary power supply 3 to the heating unit 1b.

The power supply from the auxiliary power supply 3 is required when a large amount of power is required in a short time such as when the apparatus is started, or when the main power supply is performed during a continuous heating operation. There is a case where it is inappropriate to supply a large amount of power suddenly, such as when the power of 2 is slightly insufficient. Therefore, as in the example shown in FIG. 3, the discharge circuit from the auxiliary power supply 3 to the auxiliary heating element 1b includes a discharge circuit that does not include a constant voltage circuit and can supply large power in a short time and a constant voltage circuit. At least two discharge circuits capable of supplying constant power
It is preferable to provide a type of discharge circuit.

When the heating unit starts up from a low temperature of about room temperature to the operating temperature, such as when the power of the apparatus is turned on or when the operation is started after a standby state, the heating unit is discharged at once and the temperature is raised for a short time. When the temperature of the heating unit 1 is not so low as in the temperature drop during continuous paper feeding of the fixing device but the power supply from the main power supply 2 is slightly insufficient, a constant voltage circuit is provided in the discharge circuit. Thus, the amount of discharge from the auxiliary power supply 3 including a capacitor is controlled, and the temperature of the heating unit 1 is easily controlled.

FIG. 4 shows an example in which the above-described heating device is applied to a fixing device of an image forming apparatus. As shown in FIG. 4, the fixing device has a fixing roller as a heating unit 1 and a pressure roller 1c as a pressure contact member. The fixing roller has a main heating element 1a and an auxiliary heating element 1b. Heating element 1a,
Although a halogen heater is generally used as 1b, it is not particularly limited to the halogen heater, but may be a resistance heating element or the like. The heating elements 1a and 1b generate heat by being supplied with electric power from the main power supply unit 2 or the auxiliary power supply unit 3 shown in FIGS. 1 to 3, and increase the temperature of the heating unit 1 to increase the temperature of the heating unit 1 such as paper and OHP film. An unfixed image such as a toner formed on the heating body is heated and melted to fix the toner on the sheet.

The heating device according to the present invention is not only a fixing device according to the embodiment shown in FIG. 4, but also, for example, heats a transfer paper carrying an image to improve the surface properties (such as gloss). It can be widely used as a heating device such as a device, a device for temporarily attaching, and a device for feeding and drying or laminating a sheet.

FIG. 5 shows an example of an image forming apparatus using the heating device of the present invention as a fixing device. In FIG. 5, reference numeral 41 denotes an example of an image carrier formed of a rotating body, which indicates a drum-shaped photoconductor. Around the photoreceptor 41, in the order of rotation of the photoreceptor 41 indicated by an arrow, a charging unit 42 formed of a charging roller, a mirror 43 constituting a part of the exposure unit, a developing unit 44 having a developing roller 44a, Transfer means 4 for transferring the developed image to transfer paper as member P
8, a cleaning means 46 having a blade 46a which is in sliding contact with the peripheral surface of the photoreceptor 41 is disposed. Exposure light Lb is scanned over the photoreceptor 41 via a mirror 43 between the charging means 42 and the developing roller 44a. The irradiation position of the exposure light Lb is referred to as an exposure unit 150.

The transfer means 48 faces the lower surface of the photosensitive member 41. The facing part is the transfer part 47. The recording member P is conveyed to the transfer unit 47 from right to left in FIG. A pair of registration rollers 49 is provided at a position upstream of the recording member P in the transport direction as viewed from the transfer unit 47. The recording member P stored in a paper feed tray (not shown) guided by a transport guide (not shown) is fed out from the paper feed roller 110 toward the registration roller 49. Transfer unit 4
7, the fixing device 10 described above is disposed downstream of the recording member P in the transport direction.

In this image forming apparatus, image formation is performed as follows. The photoreceptor 41 starts rotating, and during this rotation, when the surface of the photoreceptor 41 is dark,
The charged surface is irradiated with the exposure light Lb from the exposure unit 150 and scanned to form a latent image corresponding to an image to be created. This latent image is moved to the position of the developing unit 44 by the rotation of the photoconductor 41, where it is visualized by toner to form a toner image.

On the other hand, the feeding of the recording member P on the sheet feeding tray by the sheet feeding roller 110 is started, and the recording member P is temporarily stopped at the position of the pair of registration rollers 49 via the conveyance path shown by the broken line, and The transfer timing is awaited so that the toner image on the toner image 41 and the transfer unit 47 coincide with each other. When a suitable timing arrives, the recording member P stopped at the registration roller 49 is sent out from the registration roller 49 and is conveyed to the transfer unit 47. The toner image on the photoconductor 41 and the recording member P coincide with each other at the transfer section 47, and the toner image is transferred onto the recording member P by an electric field generated by the transfer unit 48.
Thus, the recording member P carrying the toner image in the image forming section around the photoconductor 41 is sent out to the fixing device 10. The toner image on the recording member P is fixed to the recording member P while passing through the fixing device 10, and is discharged to a discharge unit (not shown). That is, the recording member P is a heated member when viewed from the heating device in the fixing device 10.

On the other hand, the photosensitive member 4
The residual toner remaining on the photosensitive drum 41 reaches the cleaning device 46 as the photosensitive member 41 rotates, and the cleaning device 46
The cleaning is performed while the sheet passes through to prepare for the next image formation.

If the main power supply 2 of the entire apparatus is cut off in a state where the charge amount of the capacitor which is the auxiliary power supply 3 of the heating device is insufficient, and the charge amount of the capacitor is small at the next start-up,
There is a possibility that sufficient auxiliary power is not supplied at startup. Therefore, when the main power supply 2 of the entire apparatus is turned off,
After the capacitor is fully charged, it is desirable to turn off the power and prepare for the next startup.

Next, specific embodiments will be described. Example 1 Electric power was supplied to the heater of the fixing device shown in FIG. 4 and charging and discharging of the capacitor were performed by the circuit shown in FIG. The fixing roller serving as a heating unit is formed of an iron hollow cylindrical metal core having an outer diameter of 40 mm and a thickness of 1 mm, and a thickness of 30 μm in order to enhance the surface releasability.
m PTFE layer was provided. The pressure roller has an outer diameter of 40 mm and a thickness of 3 mm around the aluminum core.
mm silicone rubber elastic layer was provided. A load was applied to the pressure roller using a spring in the rotation axis direction of the fixing roller, and the nip width of the pressure contact portion was about 8 mm. Further, a thermocouple for detecting the temperature of the fixing roller and a program for determining whether or not the heating operation is being performed are provided as a device state detecting means (not shown).

When the heating operation was started, the capacitor was switched to a discharge circuit for connecting the capacitor to the heater. When the heating operation was changed to a non-heating operation, the capacitor was switched to a charging circuit for connecting the capacitor to the charger. The startup time from the start of the heating operation until the fixing roller temperature reaches the feasible fixing temperature depends on the power supply from the commercial power supply as the main power supply and the power supply from the capacitor as the auxiliary power supply. Compared to the case where the supply was performed, the time could be shortened. Further, the heating operation and the non-heating operation were repeated, and each time the charging and discharging of the capacitor were repeated 10,000 times, but the capacitor was hardly deteriorated, and no practical problem occurred.

Comparative Example 1 The procedure of Example 1 was repeated, except that a secondary battery was used as an auxiliary power supply. When the secondary battery was charged and discharged 2,000 times, the battery was deteriorated. Time savings are no longer observed. In addition, when the battery container was continuously connected to the charging circuit for a long time, the battery container expanded and deformed due to generation of gas.

Example 2 In Example 1, power was supplied and the capacitor was charged and discharged using the circuit shown in FIG. 3 instead of the circuit shown in FIG. The apparatus further includes a thermocouple for detecting the temperature of the fixing roller, a voltmeter for detecting the charge amount of the capacitor, and a program for determining whether or not the heating operation is being performed. When the heating operation is started at a fixing roller temperature equal to or lower than a predetermined temperature (100 ° C. in this example), the capacitor is switched to a discharging circuit that does not include a constant voltage circuit. If the temperature is lower than the lower limit temperature of the feasible temperature range (160 ° C. to 190 ° C. in this example), or if the heating operation is started when the fixing roller temperature is equal to or higher than the predetermined value, the capacitor is not included in the constant voltage circuit. When the operation was switched to the discharge circuit, and the operation was changed from the heating operation to the non-heating operation, the capacitor was switched to a charging circuit having a charger.

When the temperature of the fixing roller is raised from a low temperature to a fixing temperature (for example, 180 ° C.), a large amount of power can be supplied in a short time, and it can be started in a short time. In addition, when the temperature of the fixing roller is increased from a relatively high temperature to a fixable temperature, the supply power is controlled by a constant voltage circuit, so that the fixing roller temperature does not excessively increase.
Moderate temperature rise was possible.

Embodiment 3 As the fixing device of the image forming apparatus shown in FIG. 5, the fixing device according to the present invention was used. When the power of the entire apparatus is on, the same control as in the second embodiment is performed. When the signal of the power of the entire apparatus is off, the capacitor is connected to the charging circuit, and the charge amount of the capacitor is set to the maximum value. After charging until the power was turned off, the power was turned off. When the power was turned on after 24 hours, the charged amount of the capacitor was sufficient, and the startup time of the device was 10 seconds or less.

[0056]

According to the first aspect of the present invention, the heating element for increasing the temperature of the heating section for heating the object to be heated, and the power supply means for supplying electric power to the heating element, In a fixing device having a main power supply for supplying electric power using a commercial power supply and an auxiliary power supply including a capacitor, a charging mode for connecting the capacitor to a charging circuit and a discharging mode for connecting to a discharging circuit connected to the heating element Since the switching means is provided for switching between the charging and discharging of the capacitor, it is possible to provide a heating device capable of appropriately controlling the charging and discharging of the capacitor by switching the charging and discharging of the capacitor.

According to a second aspect of the present invention, in the heating device according to the first aspect, a detecting means for detecting a state of the apparatus is provided, and two modes of charging and discharging are performed in accordance with a value detected by the detecting means. Since the switching is performed, the switching timing of charging and discharging of the capacitor can be appropriately performed.

According to the third aspect of the present invention, in the heating device according to the second aspect, the discharge circuit includes a circuit including a constant voltage circuit and a circuit not including the constant voltage circuit, so that a discharge amount of the capacitor is provided. Can be controlled.

According to a fourth aspect of the present invention, in the heating device of the third aspect, means for detecting a temperature of the heating section is provided, and the capacitor is discharged when the temperature of the heating section is equal to or lower than a predetermined temperature. In this case, since the discharge is performed by a circuit that does not include the constant voltage circuit, the start-up time can be reduced by supplying a large amount of power in a short time.

According to a fifth aspect of the present invention, in the heating device of the third aspect, there is provided means for detecting a temperature of the heating section, and the capacitor is discharged when the temperature of the heating section is equal to or higher than a predetermined temperature. In this case, since the discharge is performed by the circuit including the constant voltage circuit, an excessive rise in the temperature of the heating unit can be prevented by supplying the constant voltage.

According to the sixth aspect of the present invention, a fixing device for fixing an unfixed image on a recording material is constituted by the heating device according to any one of the first to fifth aspects. In a fixing device using a large-capacity capacitor, it is possible to provide a fixing device capable of appropriately controlling charging and discharging of the capacitor.

According to a seventh aspect of the present invention, an image forming apparatus including the fixing device according to the sixth aspect is configured. Therefore, in an image forming apparatus using a large-capacity capacitor as an auxiliary power source, a capacitor as an auxiliary power source is provided. It is possible to provide an image forming apparatus capable of appropriately controlling the charge and discharge of the image.

According to the eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, when the main power supply of the entire apparatus is turned off, the capacitor as the auxiliary power supply is fully charged, and then the power supply is turned off. Therefore, the capacitor can be fully charged at the next start-up, and the start-up time can be shortened.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a heating device according to the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the heating device according to the present invention.

FIG. 3 is a circuit diagram showing still another embodiment of the heating device according to the present invention.

FIG. 4 is a front view schematically showing an embodiment of a fixing device having a heating device according to the present invention.

FIG. 5 is a front view showing an embodiment of an image forming apparatus having a fixing device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating part 1a Main heating element 1b Auxiliary heating element 2 Main power supply 3 Auxiliary power supply 4 Charger 5 Switching means 6 Control means 9a Detecting means 9b Detecting means 41 Image carrier 42 Charging means 44 Developing means 48 Transfer means

[Procedure amendment]

[Submission date] January 8, 2002 (2002.1.8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 8

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

The invention according to claim 8 is the invention according to claim 7, wherein when the main power switch of the device is turned off , the capacitor is brought into a fully charged state and then turned off. .

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, a main power switch of the apparatus is provided.
When the power supply is turned off , the capacitor as the auxiliary power supply is set to the fully charged state and then to the power off state, so that the capacitor is fully charged at the next start-up to shorten the start-up time. Can be.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/00 398 G03G 21/00 398 F term (Reference) 2H027 DA12 EA12 EC20 ED25 EE07 EF09 EF17 ZA01 2H033 AA32 BA30 BB01 CA07 CA27 CA48 3K058 AA02 AA87 BA18 CA03 CA12 CA22 CA23 CA31 CB01 CB12 CC03 CD04 DA11 GA06

Claims (8)

[Claims] 1. A heating unit for heating an object to be heated, a heating unit for increasing the temperature of the heating unit, and power supply means for supplying power to the heating unit. The power supply means is a heating device having a main power supply consisting of a commercial power supply and an auxiliary power supply consisting of a capacitor, wherein the capacitor is connected to a charging mode for connecting the capacitor to a charging circuit and to a discharging circuit connected to the heating element. A switching device for switching to a discharge mode for performing heating. 2. A device for detecting a state of the apparatus, comprising:
2. The heating device according to claim 1, wherein the capacitor is switched to a charge mode or a discharge mode in accordance with a value detected by the detection unit. 3. The discharging circuit includes a circuit including a constant voltage circuit,
The heating device according to claim 2, further comprising a circuit that does not include a constant voltage circuit. 4. A device for detecting a temperature of a heating unit, wherein when the temperature of the heating unit is discharged below a predetermined temperature, the capacitor is discharged by a circuit that does not include a constant voltage circuit. The heating device according to claim 3. 5. A device for detecting a temperature of a heating unit, wherein when the temperature of the heating unit is discharged at a predetermined temperature or more, the capacitor is discharged by a circuit including a constant voltage circuit. Item 4. The heating device according to Item 3. 6. A heating device according to claim 1, wherein an unfixed image on a recording material, which is a member to be heated, is heated, and the unfixed image is fixed on the recording material. Characteristic fixing device. 7. An image carrier, charging means for charging the surface of the image carrier, exposure means for exposing the charged surface of the image carrier to form an electrostatic latent image, Developing means for supplying toner to visualize the electrostatic latent image with the toner image; transfer means for transferring the toner image onto a recording material; and fixing for heating the toner image on the recording material to fix it on the recording material 7. An image forming apparatus comprising: a fixing device according to claim 6; 8. The image forming apparatus according to claim 7, wherein when the main power of the entire apparatus is turned off, the capacitor is set to a fully charged state and then turned off.