JP2009245744A - Heating apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating apparatus for shortening a rising time, obtaining high heating efficiency and attaining miniaturization and power saving, and an image forming apparatus for shortening a rising time and attaining miniaturization and power saving. <P>SOLUTION: The heating apparatus includes a heating part whose temperature rises when a heating member generates heat; a main power source formed of a commercial power source for supplying electric power to the heating member in the heating part; and an auxiliary power source formed of a power storage device charged by the supply of electric power from the commercial power source constituting the main power source. The power storage device is composed of an electrochemical capacitor with energy density per single cell being 10 Wh/kg or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

    The present invention relates to a heating device and an image forming apparatus, and more particularly, a heating device used as a heating source of a fixing device in an image forming apparatus such as a copying machine, a printer, and a facsimile, and a fixing device having the heating device as a heating source. The present invention relates to an image forming apparatus including

Image forming apparatuses such as copiers, printers, facsimiles, and the like perform a process of forming and recording an image on a recording medium such as plain paper or an overhead projector (hereinafter also referred to as “OHP”) film. A visible image is formed on a medium.
Some of these image forming apparatuses employ various image forming and recording methods. Among these image forming and recording methods, electrophotographic methods are widely used from the viewpoint of high speed, image quality, cost, and the like. It is used.

  In an image forming apparatus adopting an electrophotographic method, an unfixed image such as an unfixed toner image is formed on a recording medium, and the unfixed image is fixed by heat and pressure. As a result, a visible image is formed. In a fixing device used in such a fixing process, a heat roller method is currently most frequently used as a fixing method from the viewpoint of high speed and safety.

The heat roller method is referred to as a nip portion by press-contacting a heating roller formed of a heating device having a heating unit including a heating member such as a halogen heater and a pressure roller disposed to face the heating roller. An unfixed image formed on the recording medium is formed by forming a mutual pressure contact portion and passing the sheet-shaped recording medium on which the unfixed image is formed through the nip formed on both rollers and heating the sheet-shaped recording medium. This is a fixing method.
In such a heat roller type fixing device, a metal roller made of iron or aluminum is mainly used as a heating roller. Since this metal roller has a large heat capacity, it reaches a usable temperature of around 180 ° C. In order to raise the temperature, there is a disadvantage that a long start-up time of several minutes to several tens of minutes is required.

  Thus, in an image forming apparatus including a heat roller type fixing device, an image is formed with the main power switch turned on so that the user does not wait for the temperature of the heating roller to rise. Even in the standby state, the temperature is always kept slightly lower than the usable temperature (operating temperature) so that the heating roller of the fixing device can be immediately raised to the usable temperature. That is, in the heating device constituting the heating roller, power is supplied to the heat generating member even when the image forming apparatus is in a standby state. Therefore, in the image forming apparatus having such a configuration, extra energy that does not directly contribute to image formation is consumed even in a standby state in which the apparatus itself is not used for image formation. The energy consumption may occupy about 70 to 80% of the total energy consumption of the entire apparatus.

In recent years, laws and regulations for power saving and energy saving have been enacted in each country due to increasing awareness of environmental protection. In order to save power in the image forming apparatus as described above corresponding to these regulations and programs, it is necessary to reduce the energy consumption in the standby state where the ratio of the energy consumption of the entire image forming apparatus is large. It is effective, and it is desirable that the power supply for heating the heating roller, that is, the power supply to the heating device, is made zero except during image formation.
However, in a conventional heat roller type fixing device, when the power supply to the heating device (hereinafter also referred to as “power supplied to the heating roller”) is zero when the image forming apparatus is in a standby state. When the image is formed again, it takes a long time to raise the temperature of the heating roller to the usable temperature, so that the waiting time becomes long and the usability of the user deteriorates. There is. For this reason, a configuration for quickly increasing the temperature of the heating roller is required for realizing an energy-saving image forming apparatus.

Therefore, in order to shorten the heating time of the heating roller, it is only necessary to increase the input energy per unit time, that is, the rated power. In fact, the power supply voltage is 200 V for a high-speed machine with a high printing speed. Some are doing it.
However, in general offices in Japan, the power supply is generally 100V / 15A and 1500W is the upper limit, and in order to support 200V, it is necessary to perform special work related to the power supply at the place where the equipment is installed. It's not a general solution. For this reason, since the temperature of the heating roller is raised in a short time, the actual situation is that the upper limit of the input energy cannot be increased.

Thus, various proposals have been made to save power in an image forming apparatus provided with a heat roller type fixing device (see, for example, Patent Documents 1 to 4).
Specifically, for example, in a heating device that is a heating source of a fixing device, a rechargeable secondary battery is used as an auxiliary power source together with a main power source (see, for example, Patent Document 3). Here, as a secondary battery, a lead storage battery and a CADNICA battery are typical.

In Patent Document 1, as a power supply means for heating the heating roller, a heating device having a configuration in which an auxiliary power source including a storage battery for heating the entire device is provided together with a main power source. That is, this heating device is not configured to increase the amount of power supplied to the heating roller by the auxiliary power source.
Patent Document 2 proposes a heating device having a configuration in which a main power source and an auxiliary power source are provided as power supply means for heating the heating roller of the fixing device. Simply indicates that two levels of power are supplied from a single power supply, and is intended to increase the maximum amount of power supplied to the heating roller by using both the main power supply and the auxiliary power supply. is not.
In Patent Document 3, an image forming apparatus is proposed in which an auxiliary power source is provided together with a main power source in a fixing device, and various functions can be exhibited by using the auxiliary power source. The auxiliary power source in this image forming apparatus is composed of a power storage device such as a secondary battery or a primary battery.

However, in the case where a secondary battery is used as an auxiliary power source, there are the following problems, which are difficult to realize in practice.
A secondary battery has the property that it deteriorates as it is repeatedly charged and discharged many times, its capacity gradually decreases, and its life is shortened as it is discharged at a large current. Even for a CADNICA battery that is generally considered to have a long life with a large current, the number of times that charge and discharge can be repeated is about 500 to 1000 times. For example, when charging and discharging 20 times a day is repeated. The battery life will be exhausted in about one month. Therefore, it takes time to replace the battery, and the running cost such as the battery cost becomes very high. Furthermore, since it takes a long time to charge, it is necessary to charge at night or take it out of the apparatus and charge it. Moreover, the discharge is little by little, and it is difficult to take out a large amount of power in a short time. If the battery is continuously charged when there is no need for discharge, gas is generated, causing failure, which is not safe. In particular, a lead storage battery is not preferable for office equipment, such as using liquid sulfuric acid.

As another specific example, there is a recent proposal using an electric double layer capacitor as an auxiliary power source (for example, Patent Document 4).
Patent Document 4 discloses that an electric double layer capacitor used as an auxiliary power source has almost unlimited number of charge / discharge cycles, there is almost no deterioration in charge characteristics, and no periodic maintenance is required. It can be as short as several seconds to several tens of seconds, and a large current of several tens to several hundreds of amperes can flow, so various types of power can be supplied in a short time It is described that it has the following characteristics.

  However, since the electric double layer capacitor usually has a small energy density of 5 Wh / kg or less per unit cell, there is a limit to the power supply time, that is, the discharge capacity, and the voltage per unit cell is about 2.5 V. Since it is low, it is necessary to connect a large number of cells in series in order to obtain the high voltage energy capacity required as an auxiliary power supply, and a large space is required to arrange such a large capacity electric double layer capacitor. As a result, there is a problem in that an image forming apparatus provided with such an electric double layer capacitor cannot be obtained with good space efficiency and becomes large.

Japanese Patent Laid-Open No. 05-232839 JP-A-10-010913 Japanese Patent Laid-Open No. 10-282821 JP 2002-280146 A

The present invention has been made based on the circumstances as described above, and its purpose is to shorten the rise time and to obtain high heating efficiency, and to achieve miniaturization and power saving. It is providing the heating apparatus which can be performed.
Another object of the present invention is to provide an image forming apparatus capable of reducing the rise time and reducing the size and power consumption.

The heating device according to the present invention includes a main power source including a heating unit in which the temperature rises when the heating member generates heat, a commercial power source for supplying power to the heating member in the heating unit, and the main power source. An auxiliary power source comprising a power storage device charged by power supply from a commercial power source,
The power storage device is constituted by an electrochemical capacitor having an energy density per unit cell of 10 Wh / kg or more.

  In the heating device of the present invention, the electrochemical capacitor constituting the power storage device is preferably a lithium ion capacitor.

  In the heating device of the present invention, the upper limit value of the voltage per unit cell of the electrochemical capacitor constituting the power storage device is in the range of 3.6 to 4.0 V, and the lower limit value is in the range of 1.8 to 2.5 V. It is preferable to provide a control mechanism for controlling the inside.

  In the heating device of the present invention, it is preferable that the electrochemical capacitor constituting the power storage device has a configuration in which a plurality of single cells are connected in series.

An image forming apparatus according to the present invention includes an unfixed image forming apparatus that forms an unfixed image on a recording medium, and a fixing apparatus that heats and fixes the unfixed image formed on the recording medium by the unfixed image forming apparatus. An image forming apparatus comprising:
The fixing device includes the heating device described above, and heats an unfixed image formed on a recording medium by the heating device.

  In the image forming apparatus of the present invention, when the main power switch that converts the power supply state by turning on and off is turned off, after the electrochemical capacitor constituting the power storage device in the heating device is in a fully charged state, It is preferable to enter a power-off state in which power supply is stopped.

  According to the heating device of the present invention, an auxiliary power source is provided together with the main power source as power supply means for supplying power to the heating unit, and the auxiliary power source has an energy density of 10 Wh / kg per unit cell. Since it is comprised by the above electrochemical capacitor, the big electric power exceeding the power supply capability which a commercial power supply has can be supplied to a heating part in a very short time of several seconds to several tens of seconds. Therefore, the temperature of the heating section can be raised from room temperature to a high operating temperature in a short time without preheating, and therefore power saving can be achieved and the rise time can be shortened. Can do. In addition, since the number of cells required for the electrochemical capacitor is reduced in order to obtain a large voltage for the auxiliary power supply, high heating efficiency can be obtained and downsizing can be achieved.

  In the heating device of the present invention, since the auxiliary power source of the heating device is constituted by an electrochemical capacitor, the number of times that the electrochemical capacitor itself can be repeatedly charged and discharged is almost unlimited, and the charging characteristics are deteriorated. Since there is almost no charge and no periodic maintenance is required, excellent durability and good maintainability can be obtained, and even if charging continues within the rated range, gas is generated. There is no safety.

  According to the image forming apparatus of the present invention, since the heating device of the present invention is used as a heating source of the fixing device, the rise time can be shortened and the size and power can be reduced. .

  Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing an example of a circuit configuration of the heating device of the present invention.
The heating device includes a heating unit 11 including a first heat generating member 12A and a second heat generating member 12B that generate heat when power is supplied, and power is supplied to the first heat generating member 12A. A main power source 14 composed of a commercial power source for supply and an auxiliary power source 20 composed of a power storage device for supplying power to the second heat generating member 12B are provided as power supply means.
In FIG. 1, 16 is a charger having a rectifying function and a voltage adjusting function, which is used when power is supplied from the main power supply 14 to the auxiliary power supply 20 that needs to be charged by a direct current. , 18 is a charge / discharge switching means for switching charge / discharge of the auxiliary power supply 20, and 18 is for controlling power supply from the main power supply 14 to the first heat generating member 12A in order to control the temperature of the heating unit 11. It is a control means. According to the charge / discharge switching means 17, a charging circuit in which the auxiliary power source 20 is connected to the main power source 14 via the charger 16, or a discharging circuit in which the auxiliary power source 20 is connected to the second heat generating member 12B. Is formed, and switching to one of these circuits switches charging / discharging of the auxiliary power supply 20.

As each of the first heat generating member 12A and the second heat generating member 12B constituting the heating unit 11, for example, a halogen heater can be used, and other resistance heat generating elements can be used.
Here, when the heating device is used as a heating source of the fixing device of the image forming apparatus, a high-efficiency halogen heater is usually used as the heat source as the first heating member 12A and the second heating member 12B of the heating device. Used.

  The main power supply 14 is a commercial power supply that can be taken in from an outlet or the like, but may have functions such as voltage adjustment and rectification according to the constituent members of the first heat generating member.

  The control means 18 for controlling the power supply from the main power source 14 to the first heat generating member 12A is composed of a control device such as a switch and a CPU, and the first heat generating member from the main power source 14 according to preset conditions. The structure which implement | achieves on-off operation | movement of conduction to 12A may be sufficient.

  The auxiliary power source 20 is a power storage device and is charged via the charger 16 by power supply from the main power source 14, and has an energy density of 10 Wh / kg or more per unit cell (hereinafter, “ It is also called “specific electrochemical capacitor”).

Here, in general, an “electrochemical capacitor” means an electric double layer capacitor and a redox volume (redox capacitor) or pseudocapacitance (pseudocapacitance capacitor) due to charge transfer at the electrode interface, An ionic liquid capacitor using a combination of these two types (hybrid capacitor) and an ionic solution as an electrolyte is shown.
A lithium ion capacitor is a kind of hybrid capacitor.

Unlike the secondary battery, this electrochemical capacitor has a limited chemical reaction. Specifically, the charging / discharging mechanism of the electrochemical capacitor follows the Faraday's law based on an oxidation-reduction reaction involving the movement of electrons. Unlike secondary battery charging / discharging mechanisms, it is based solely on electrostatic interactions on the surface of the material, and does not depend on Faraday's law, or a combination of actions that do not depend on Faraday's law and reactions that follow Faraday's law. Yes, it has excellent characteristics because of its relatively low utilization of chemical reactions.
The excellent characteristics of the electrochemical capacitor will be described below by comparing with a secondary battery.

(1) Charging time is short:
When a general nickel-cadmium battery as a secondary battery is used as an auxiliary power source, it takes several hours to charge even if rapid charging is performed. On the other hand, by using an electrochemical capacitor as an auxiliary power source, rapid charging of about several minutes is possible, and therefore charging and discharging can be performed frequently. Therefore, when compared within the same time, nickel- Compared with the case where a secondary battery such as a cadmium battery is used as an auxiliary power source, the number of times the auxiliary power source is used (the number of times of heating using the auxiliary power source) can be increased.

(2) Long life:
Since the nickel-cadmium battery can be repeatedly charged and discharged 500 to 1000 times, it has a short life as an auxiliary power source for the heating unit in the heating device, and there is a problem in labor and cost of replacement. On the other hand, the electrochemical capacitor has an order of magnitude of life and is less deteriorated by repeated charge and discharge. Therefore, the image forming apparatus is particularly advantageous as a power source for a heating unit of a heating device used as a heating source of a fixing device in which a non-heating operation in a standby state and a heating operation in an operation state are repeated.
Moreover, since lead exchange batteries do not require liquid replacement or replenishment, maintenance is almost unnecessary.

(3) High-power short-time discharge is possible:
Because the secondary battery cannot discharge the stored power at a stretch, when the secondary battery is used as an auxiliary power source, it cannot supply a large amount of power even when starting up the heating unit from a low temperature. I cannot hope for a high effect in shortening the start-up time. On the other hand, since an electrochemical capacitor can discharge a large amount of power in a few seconds, it is effective for shortening the startup time by using it as an auxiliary power source.

  In the specific electrochemical capacitor constituting the auxiliary power source 20, the energy density per unit cell is required to be 10 Wh / kg or more, and the higher the energy density per unit cell, the better. It is said.

When the energy density per unit cell of the electrochemical capacitor is less than 10 Wh / kg, the voltage per unit cell becomes small and sufficient discharge capacity cannot be obtained. Therefore, high heating efficiency cannot be obtained, and it is impossible to achieve downsizing and power saving.
Here, when the heating device is used as a heating source of the fixing device in the image forming apparatus, the auxiliary power source (electrochemical capacitor) needs to have an energy capacity of at least about 10 Wh in order to fulfill its role. The
Specifically, from the viewpoint of dischargeable time (discharge capacity), a 500 F, 50 V rated electrochemical capacitor (lithium ion) in which 13 single cells having a rating of 3.9 V and an energy density of 10 Wh / kg or more are connected in series. In the case of the capacitor, the operating voltage range is 28 to 50 V, and when discharging is performed under the condition of a current of 10 A, the dischargeable time is about 80 seconds. On the other hand, a 500 F, 50 V rated electrochemical capacitor (electric double layer capacitor) in which 20 single cells having a rating of 3.9 V and an energy density of less than 10 Wh / kg are connected in series has an operating voltage range of 28- When discharging is performed under the condition of 50 V and a current of 10 A, the dischargeable time is about 55 seconds.

The specific electrochemical capacitor has an upper voltage limit (hereinafter also referred to as “voltage upper limit value”) per unit cell of 3.6 to 4.0 V, and a lower limit value (hereinafter referred to as “voltage lower limit value”). It is preferable that it is 1.8-2.5V. The voltage upper limit value is particularly preferably 3.7 to 3.9V, while the voltage lower limit value is particularly preferably 2.0 to 2.2V.
In a specific electrochemical capacitor, when the voltage upper limit value and the voltage lower limit value are within a specific range, a high voltage can be obtained with high efficiency.
That is, for example, when a heating device provided with a halogen heater as the first heat generating member 12A and the second heat generating member 12B is used as a heating source of a fixing device of an image forming apparatus, a high voltage (specifically required) Specifically, 40 to 50 V) can be obtained by connecting a small number (specifically, 10 to 14) of cells in series.
When an electric double layer capacitor is used as an auxiliary power source, the electric double layer capacitor needs to have a configuration in which 16 or more cells are connected in series.

A preferred specific example of the specific electrochemical capacitor is a lithium ion capacitor.
The reason why a lithium ion capacitor is suitable as a specific electrochemical capacitor is that this lithium ion capacitor usually has an upper voltage limit of 3.6 to 4.0 V and a lower voltage limit of 1.8 to 2.5 V. Yes, in such a voltage range, when the capacitance is 500 F or more, the energy density per unit cell can be easily adjusted by adjusting the capacitance (absolute capacitance) or the basis weight of the electrode, for example. This is because it can be set to 10 Wh / kg or more.
Moreover, since the volume of the lithium ion capacitor hardly decreases due to self-discharge and the energy retention is high, the lithium ion capacitor can be restarted in a short time after the pause time is long.
In addition to this lithium ion capacitor, as a specific electrochemical capacitor, for example, a redox capacitor using an organic conductive polymer, a pseudocapacitor using hydrated ruthenium oxide, and the like can be used.

  In this heating apparatus, it is preferable that a control mechanism is provided for setting the voltage upper limit value and the voltage lower limit value per unit cell of the specific electrochemical capacitor constituting the auxiliary light source 20 within a specific range.

As a specific example of the control mechanism, for example, an upper limit voltage control circuit for preventing overcharge and a lower limit electricity prevention circuit for preventing overdischarge can be cited.
In the example of FIG. 1, as a control mechanism, an upper limit voltage control circuit is provided in the charging circuit, and a lower limit electricity prevention circuit is provided in the discharge circuit.

The heating device having such a configuration selectively forms a discharge circuit by the charge / discharge switching means 17 in a state where the auxiliary power source 20 is sufficiently charged (for example, a full charge state), and the auxiliary power source 20 is By connecting to the second heat generating member 12B, power is supplied from the main power source 14 to the first heat generating member 12A, and power is also supplied from the auxiliary power source 20 to the second heat generating member 12B. Therefore, large power exceeding the power supply capability of the commercial power supply can be supplied to the heating unit 11 by supplying power from the two power supplies.
Here, when the auxiliary power source 20 is not sufficiently charged, a charging circuit is formed by the charge / discharge switching means 17, and the auxiliary power source 20 is connected to the main power source via the charger 16. 14, it is necessary to perform charging by supplying power from the main power supply 14.

  And since the auxiliary power supply 20 consists of the specific electrochemical capacitor whose energy density per unit cell is 10 Wh / kg or more, supply of the big electric power exceeding the power supply capability which the commercial power supply has with respect to the heating part 11 is several seconds. Since it can be performed in a very short time of ˜several tens of seconds, the temperature of the heating unit 11 can be raised from room temperature to a high operating temperature in a short time without preheating. And rise time can be shortened. Further, since the number of cells required for a specific electrochemical capacitor is reduced in order to obtain a large voltage at the auxiliary power source 20, high heating efficiency can be obtained and downsizing can be achieved. Specifically, the electrochemical capacitor can increase the voltage per unit cell by 1.5 times as compared with a conventionally known electric double layer capacitor. Can be reduced to 2/3 times or less.

  In addition, the auxiliary power supply 20 has the characteristics that the electrochemical capacitor itself has an unlimited number of charge / discharge cycles, has almost no deterioration in charge characteristics, and does not require regular maintenance. Therefore, excellent durability and good maintainability can be obtained, and even if charging is continued within the rated range, there is no generation of gas and it is safe.

  As will be described later, such a heating device can be suitably used as a heating source in a fixing device of an image forming apparatus. However, the heating device is not only used as a heating source of a fixing device but also, for example, heats a recording medium carrying an image. It can also be used as a heating source for a device for modifying the surface properties (such as glazing), a device for performing assumed attachment, a device for drying a sheet-like body, and a laminating device.

  An image forming apparatus of the present invention includes an unfixed image forming apparatus that forms an unfixed image on a recording medium, and a fixing apparatus that heats and fixes the unfixed image formed on the recording medium by the fixed image forming apparatus. The heating device of the present invention is provided as a heating source of the fixing device.

In the fixing device of this image forming apparatus, an unfixed image formed on a recording medium is heated by a heating device that is a heating source. The heat source, that is, the first heat generating member and the first heating member that constitute the heating device. As the heat generating member 2, a halogen heater having high thermal efficiency is usually used. When a halogen heater is used as a heat source in this way, the current capacity is at most about 10 to 12 A in order to extend the life of the halogen heater. Therefore, the halogen heater is preferably heated at a high voltage. Usually, a voltage of 40 V or more is required.
In addition, when an electric double layer capacitor is used as an auxiliary power source, the electric double layer capacitor has a voltage per unit cell of about 2.5 V. Therefore, in order to obtain a voltage of 40 V or more, the configuration is used. It is necessary that 16 or more cells are connected in series.

4 is an explanatory diagram showing an example of the configuration of the image forming apparatus of the present invention, and FIG. 5 is an explanatory diagram showing the configuration of the fixing device in the image forming apparatus of FIG.
The image forming apparatus includes: an unfixed image forming apparatus that forms an unfixed image on a recording medium; and a fixing device that heats and fixes the unfixed image formed on the recording medium by the unfixed image forming apparatus. The heating device according to FIG. 1 is provided as a heating source of the fixing device 30.

  Specifically, the unfixed image forming apparatus includes an image carrier 41 made of a rotating body such as a drum-shaped photoconductor, and a charging unit 42 made of a charging roller is provided around the image carrier 41. A developing unit 44 having a developing roller 44A, a transfer unit 48 for transferring an unfixed image onto a transfer sheet as a recording medium P, and a periphery of the image carrier 41. The cleaning means 46 provided with the blade 46A slidably contacting the surface is arranged in this order along the rotation direction of the image carrier 41 (the arrow direction in FIG. 4). The unfixed image forming apparatus is configured such that the exposure light Lb is scanned via the mirror 43 between the charging unit 42 on the image carrier 41 and the developing roller 44A. An exposure part 51 is formed at the irradiation position.

  In the unfixed image forming apparatus, a transfer portion 47 is formed in a portion (the lower surface in FIG. 4) where the transfer means 48 faces the image carrier 41, and the recording medium P in FIG. Are transported in the transport direction from right to left. The recording medium P is housed in a sheet feeding tray (not shown), is fed from the sheet feeding roller 56, and is a pair of registration rollers 49 provided at a position upstream of the transfer unit 47 in the conveying direction of the recording member P. Then, it is guided by a transport guide (not shown) and transported to the transfer section 47.

The fixing device 30 is disposed on the downstream side in the transport direction of the recording member P with respect to the transfer unit 47 constituting the unfixed image forming apparatus.
The fixing device 30 is of the heat roller type, is constituted by the heating unit 11 of the heating device, and includes a first heat generating member 12A and a second heat generating member made of a halogen heater inside a hollow cylindrical metal roller 32. 12B is provided, and a pressure roller 35 having a configuration in which an elastic layer 37 is provided on the outer peripheral surface of the metal roller 36, for example, disposed opposite to the heating roller. A nip portion N composed of a mutual pressure contact portion is formed by pressing the roller 35 against the roller 35.
In the example of FIG. 4, the heating roller has a configuration in which a surface release layer 33 made of, for example, PTFE is provided on the outer peripheral surface of the metal roller 32 in order to improve the surface release property.

In the image forming apparatus having such a configuration, a visible image is formed as follows. When the image forming apparatus is in the image forming operation state, in the unfixed image forming apparatus, the image carrier 41 starts to rotate, and the surface of the image carrier 41 is uniformed by the charging unit 42 in the dark during this rotation. The charged surface is irradiated with the exposure light Lb from the exposure unit 51 and scanned to form a latent image corresponding to the image pattern to be formed. This latent image is moved to the position of the developing means 44 by the rotation of the image carrier 41, where it is visualized with toner to form a toner image.
On the other hand, feeding of the recording medium P on the paper feeding tray is started by the paper feeding roller 56, whereby the recording medium P is transported along a transport path indicated by a broken line, but a pair of registration rollers 49, the toner image on the image carrier 41 is temporarily stopped for timing so as to match the toner image on the image carrier 41, sent out when a suitable timing arrives, and conveyed toward the transfer unit 47. Then, the toner image on the image carrier 41 and the recording medium P coincide with each other at the transfer portion 47, and the toner image is transferred onto the recording medium P by the electric field by the transfer means 48, whereby an unfixed image (on the recording medium P) Toner image) is formed.

Next, the recording medium P on which the unfixed image is formed in the unfixed image forming apparatus is sent to the fixing apparatus 30, and the unfixed image on the recording medium P passes through the nip portion N in the fixing apparatus. By doing so, it is heated and melted, and thereby fixed, and then discharged to a paper discharge section (not shown) to obtain a visible image.
Here, in the fixing device 30, the heating roller generates heat from the first heat generating member 12 </ b> A and the second heat generating member 12 </ b> B by power supply from the main power supply 14 or the auxiliary power supply 20, thereby increasing its temperature. Fixing is performed by heating and melting an unfixed image on the recording medium P.

  Residual toner remaining on the image carrier 41 without being transferred by the transfer unit 47 reaches the cleaning unit 46 along with the rotation of the image carrier 41 and is cleaned while passing through the cleaning unit 46 to be next. Prepared for image formation.

In the image forming apparatus as described above, since the heating device of the present invention is used as a heating source of the fixing device 30, the electric power for heating the heating roller is not accompanied by an adverse effect except during image formation. The supply, ie the power supply to the heating device, can be made zero. That is, even when the power supply to the heating device (power supplied to the heating roller) is zero when the image forming apparatus is in a standby state, a large rise time is required when performing image formation again. Since it is possible to quickly raise the temperature of the heating roller, the time required for the heating roller to rise to the usable temperature can be reduced, and therefore the waiting time is increased. Thus, it is possible to prevent user convenience from deteriorating.
In addition, since the heating device constituting the fixing device 30 can be reduced in size, the image forming apparatus itself can be reduced in size.
Therefore, according to the image forming apparatus having the configuration in which the heating device of the present invention is used as the heating source of the fixing device 30 as described above, the rise time can be shortened and the size and power can be saved. be able to.

  Further, the image forming apparatus is configured in a case where the auxiliary power source 20 constituting the heating device in the fixing device 30 is not in a sufficiently charged state when the main power switch that converts the power supply state by turning on and off is turned on. Since the power supply from the auxiliary power supply 20 is not sufficient and may take a long time to start up, the power supply is stopped immediately after the main power switch is turned off. It is preferable to have a configuration in which the power supply is not turned off but the power supply is turned off after the auxiliary power supply 20 in the heating device is fully charged. With such a configuration, it is possible to prepare for a restart after the power is turned off.

Hereinafter, the heating device and the image forming apparatus of the present invention are not limited to the above-described heating device and image forming apparatus, and various modifications can be made.
For example, the heating device may have a circuit configuration shown in FIG.

The heating apparatus according to FIG. 2 has the same configuration as that of FIG. 1 except that two detection means 22A and 22B for detecting the apparatus state are provided.
The detection means 22A is a temperature sensor that detects the temperature of the heating unit 11, and includes, for example, a thermistor or a thermocouple.
The detection means 22B is a means for detecting the charge amount of the auxiliary power source 20 made of an electrochemical capacitor. Specifically, for example, a voltmeter, a timer for measuring the discharge time or time of the auxiliary power supply 20, a means for informing the start of heating such as a heating start button or a human sensor, a means for detecting the heating operation state, etc. are used. Can do. Although these may be used independently, it is possible to perform charge / discharge control of the auxiliary power supply 20 more appropriately by combining a plurality.
Here, unlike a battery, an electrochemical capacitor has a characteristic that the voltage between terminals decreases as it is discharged. Therefore, the remaining power can also be detected by measuring the voltage between terminals of the electrochemical capacitor. Can do.

In a heating apparatus having such a configuration, for example, when a main power switch is turned on in a device such as a copying machine, or when a human sensor detects this when a person approaches the device body. The auxiliary power source 20 is connected to the second heat generating member 17 by the charge / discharge switching means 17 so that power can be supplied from the auxiliary power source 20 to the second heat generating member 12B at the same time as the power is supplied from the main power source 14 to the first heat generating member 12A. Connected to the member 12B, a discharge circuit of the auxiliary power source 20 is formed via the second heat generating member 12B.
Further, even when the temperature of the heating unit 11 falls below a predetermined temperature during the heating operation, the auxiliary power source 20 is switched by the charge / discharge switching means 17 so that power can be supplied from the auxiliary power source 20 to the second heat generating member 12B. A discharge circuit is formed by connecting to the second heat generating member 12B. Alternatively, the auxiliary power supply 20 is connected to the charger 16 by the charge / discharge switching means 17 so that the auxiliary power supply 20 is charged at a preset time, thereby forming a charging circuit.
Then, except during the heating operation, a charging circuit is formed by connecting the auxiliary power source 20 to the charger 16 by the charge / discharge switching means 17, and the auxiliary power source 20 is charged from the main power source 14 via the charger 16. As a result of detection by the detection means 22A, when the charge amount of the auxiliary power supply 20 is equal to or less than a predetermined value, the charge / discharge switching means 17 connects the auxiliary power supply 20 to the charger 16 to form a charging circuit. When the discharge time of the auxiliary power source 20 is equal to or longer than the predetermined value and the non-heating operation is being performed, the charge / discharge switching unit 17 connects the auxiliary power source 20 to the charger 16 to form a charging circuit. The above is an example, and the present invention is not limited to these.

The heating device according to FIG. 3 can switch the discharge circuit of the auxiliary power source 20 in two ways based on detection information by the temperature detection means 22A that detects the temperature of the heating unit 11, and the two ways. A constant voltage device (constant voltage circuit) 19 is interposed in one of the discharge circuits, and a constant voltage device (constant voltage circuit) 19 is not interposed in the other of the discharge circuits, and the second heat generating member 12B is directly supplied from the auxiliary power source 20. It has the same configuration as the heating device according to FIG.
Here, in the heating device, when the power supply from the auxiliary power source 20 is necessary, the case where a large amount of power is required in a short time, such as when the device is started up, and the case where the heating operation is continuously performed. In some cases, it is inappropriate to supply a large amount of power suddenly, such as when the power of the main power supply 14 is slightly insufficient. Therefore, as in the heating device according to FIG. 3, the discharge circuit from the auxiliary power source 20 to the second heat generating member 12B does not include a constant voltage circuit and can supply a large amount of power in a short time, and a constant voltage It is preferable to include at least two types of discharge circuits including a circuit and capable of supplying a constant power.

  In the heating device having such a configuration, when the heating unit 11 starts up from a low temperature of about room temperature to the operating temperature, such as when the device is turned on or starts operation after standby, the battery is discharged at once. Let the temperature rise for a short time. A constant voltage circuit is provided in the discharge circuit when the heating unit 11 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 14 is slightly insufficient. Thus, the discharge amount from the auxiliary power source 20 made of a specific electrochemical capacitor is controlled, and the temperature of the heating unit 11 can be easily controlled.

  Examples of the present invention will be described below, but the present invention is not limited thereto.

[Example 1]
A fixing device having the configuration shown in FIG. 5 was prepared, comprising a heating device having the circuit configuration shown in FIG.
In this fixing device, as a heating roller, an iron hollow cylindrical metal core having an outer diameter of 40 mm and a thickness of 0.7 mm is provided with a PTFE layer having a thickness of 30 μm in order to improve the surface releasability. In addition, as the pressure roller, an aluminum core having an outer diameter of 40 mm and a silicon rubber elastic layer having a thickness of 30 mm provided on the outer periphery was used. A load is applied to the pressure roller using a spring in the rotation direction of the heating roller, and a nip portion having a nip width of about 8 mm is formed. Further, as two detection means for detecting the state of the apparatus, a thermocouple for detecting the temperature of the heating roller and a program for determining whether or not the heating operation is being performed are provided.
And as an auxiliary power source constituting the heating device, 13 lithium ion capacitors (operating voltage range: 2.2 to 3.8 V) having a capacitance of 500 F (0.67 Wh, 12.5 Wh / kg) are connected in series. A rated module (50V) was used. The total weight of the rated module was 0.7 kg.

  In addition, when the heating operation is started, the fixing device switches the auxiliary power source (electrochemical capacitor) to a discharge circuit connected to the second heat generating member (halogen heater), while the heating operation is not performed. In the case of change, the circuit state was controlled so that the auxiliary power source was switched to the charging circuit connected to the charger.

In the fixing device having the above configuration, when the start-up time from the start of the heating operation until the heating roller temperature (normal temperature) reaches the fixing possible temperature (operating temperature: 180 ° C.) is measured, the main power supply (commercial power supply) and auxiliary It was confirmed that the start-up time can be shortened by simultaneously supplying power from the power source (electrochemical capacitor) as compared to the case where power is supplied only from the main power source.
Moreover, the heating operation and the non-heating operation were repeated, and charging / discharging of the auxiliary power supply (electrochemical capacitor) was repeated 20,000 times each time, but there was almost no deterioration of the electrochemical capacitor constituting the auxiliary power supply. There was no practical problem.

[Comparative Example 1]
In Example 1, as an auxiliary power source, a total weight of 20 electric double layer capacitors (operating voltage range: 0 to 2.5 V) having a capacitance of 500 F (0.43 Wh, 4.2 Wh / kg) connected in series. A fixing device having the same configuration as that of the fixing device of Example 1 except that a 2 kg rated module (50 V) is used is prepared, the start-up time is measured by the same method as in Example 1, and the heating operation is not performed. The heating operation was repeated 20,000 times, and the state of the auxiliary power source was confirmed.
Start-up time is compared to when power is supplied only from the main power supply (commercial power supply) by simultaneously supplying power from the main power supply (commercial power supply) and auxiliary power supply (electric double layer capacitor). Although it could be shortened, the startup time was about 15% longer than in Example 1.
Moreover, the electric double layer capacitor after repeating the heating operation and the non-heating operation 20,000 times hardly deteriorated.

[Example 2]
In Example 1, instead of the heating device having the circuit configuration shown in FIG. 2, a heating device having the circuit configuration shown in FIG. 3 is used, and as one of the two detection means for detecting the state of the device. Other than using a combination of a program for determining whether or not the heating operation is being performed and a voltmeter for detecting the charge amount of the electrochemical capacitor, instead of only the program for determining whether or not the heating operation is being performed Prepared a fixing device having the same configuration as the fixing device of Example 1.
The fixing device also includes an auxiliary power source (electrochemical capacitor) as a discharge circuit that does not include a constant voltage circuit when the heating operation is started at a temperature equal to or lower than a predetermined temperature (100 ° C.) set in advance. When the heating roller temperature falls below the lower limit temperature of the fixable temperature range (temperature range of 160 ° C. to 190 ° C.) during the heating operation, or when the heating operation is started when the fixing roller temperature is equal to or higher than the predetermined temperature. The auxiliary power supply is switched to a discharge circuit that does not include a constant voltage circuit, and when the heating operation is changed to the non-heating operation, the auxiliary power supply is switched to a charging circuit having a charger. Control the state.

When the heating roller is heated from a low temperature to a fixable temperature (180 ° C.), the fixing device having the above configuration can supply a large amount of power in a short time and can be started up in a short time. Was confirmed.
In addition, when the temperature of the heating roller is raised from a relatively high temperature to a fixable temperature, it is possible to raise the temperature appropriately without controlling the heating roller temperature excessively by controlling the power supplied by the constant voltage circuit. It was confirmed.

Example 3
When the image forming apparatus having the configuration shown in FIG. 4 is prepared and the main power switch is on, the fixing device controls the circuit state similar to that of the fixing device according to the first embodiment, and the main power switch is off. (If a signal indicating that the power supply of the entire device is turned off is input), the auxiliary power supply (electrochemical capacitor) is connected to the charging circuit, and charging is performed until the charge amount of the auxiliary power supply reaches the maximum value. After that, when the power was turned off and the power was turned on after 24 hours and 7 days, the charge amount of the auxiliary power supply was sufficient after 24 hours and 7 days, and the image forming apparatus started up. It was confirmed that the time required was 10 seconds or less.

[Reference Example 1]
In Example 3, the power supply was turned off in the same manner as in Example 3 except that the amount of charge of the auxiliary power supply when the main power switch was turned off was ½ of the maximum value. When the power was turned on after 7 days, it was confirmed that the time required for the image forming apparatus to start up was 20 seconds or less both after 24 hours and after 7 days.

[Comparative Example 2]
In the image forming apparatus according to the third embodiment, an image forming apparatus having the same configuration as that of the image forming apparatus according to the third embodiment is prepared as the fixing device except that the fixing device according to the comparative example 1 is provided. When the power switch is on, the fixing device performs the same circuit state control as that of the fixing device according to the first embodiment, and when the main power switch is turned off (a signal indicating that the entire device is powered off). In the case of input), an auxiliary power supply (electric double layer capacitor) is connected to the charging circuit, charged until the auxiliary power supply reaches the maximum value, then turned off, and after 24 hours and 7 When the power was turned on after a day, the time required to start up after 24 hours was about 30 seconds. However, after 7 days, the charge amount of the auxiliary power supply (electric double layer capacitor) decreased. Cage, the rise may take more than 2 minutes was confirmed.

It is explanatory drawing which shows an example of the circuit structure of the heating apparatus of this invention. It is explanatory drawing which shows the other example of the circuit structure of the heating apparatus of this invention. It is explanatory drawing which shows the further another example of the circuit structure of the heating apparatus of this invention. It is explanatory drawing which shows an example of a structure of the image forming apparatus of this invention. FIG. 5 is an explanatory diagram illustrating a configuration of a fixing device in the image forming apparatus of FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Heating part 12A 1st heat generating member 12B 2nd heat generating member 14 Main power supply 16 Charger 17 Charge / discharge switching means 18 Control means 19 Constant voltage device 20 Auxiliary power supplies 22A and 22B Detection means 30 Fixing device 32 Metal roller 33 Surface separation Mold layer 35 Pressure roller 36 Metal roller 37 Elastic layer 41 Image carrier 42 Charging means 43 Mirror 44 Developing means 44A Developing roller 46 Cleaning means 46A Blade 47 Transfer section 48 Transfer means 49 Registration roller 51 Exposure section 56 Paper feed roller P Recording Medium N Nip Lb Exposure light

Claims (6)

A heating unit whose temperature rises when the heating member generates heat, a main power source including a commercial power source for supplying power to the heating member in the heating unit, and a power supply from the commercial power source constituting the main power source An auxiliary power source comprising a power storage device charged by
The heating device, wherein the power storage device is constituted by an electrochemical capacitor having an energy density per unit cell of 10 Wh / kg or more.   The heating apparatus according to claim 1, wherein the electrochemical capacitor constituting the power storage device is a lithium ion capacitor.   Control mechanism for controlling the upper limit value of voltage per unit cell of the electrochemical capacitor constituting the power storage device to be in the range of 3.6 to 4.0 V and the lower limit value in the range of 1.8 to 2.5 V The heating apparatus according to claim 1, wherein the heating apparatus is provided.   The heating device according to any one of claims 1 to 3, wherein the electrochemical capacitor constituting the power storage device has a configuration in which a plurality of single cells are connected in series. Image forming apparatus comprising: an unfixed image forming apparatus that forms an unfixed image on a recording medium; and a fixing device that heats and fixes the unfixed image formed on the recording medium by the unfixed image forming apparatus Because
The fixing device includes the heating device according to any one of claims 1 to 4, and heats an unfixed image formed on a recording medium by the heating device. apparatus.   When the main power switch that converts the power supply state by turning on and off is turned off, the power supply is turned off after the electrochemical capacitor constituting the power storage device in the heating device is fully charged. The image forming apparatus according to claim 5, wherein the image forming apparatus is in a state.

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