JP2009265136A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device for preventing deformation of a fixing member or pressure member by using an inexpensive electricity-accumulating member having small capacity even when the temperature decrease gradient of the fixing member or pressure member changes according to a use condition after a main power source is turned off or during power failure. <P>SOLUTION: The fixing device includes: a temperature detecting sensor 34 which detects temperature of a fixing device 9; a drive source 42 which drives the fixing device 9 or a pressure member 33; a capacitor 44 which operates the drive source 42 by supplying accumulated auxiliary power when supply of power from the main power source is stopped; and a control circuit 40 which controls output of a heating source 31 based on a temperature detected by the temperature detecting sensor 34, which controls drive of the drive source 42 based on a temperature detected by the temperature detecting sensor 34 when supply of power from the main power source is stopped, and which, after the supply of power from the main power source is stopped, receives auxiliary power supplied from the capacitor 44, and intermittently controls drive of the drive source 42 in terms of intervals and frequency of the driving operation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing device for heating and pressure-fixing an image formed on the surface of a transfer paper used in a copying machine, a printer, a facsimile machine, or a multifunction machine equipped with these functionally, and an image provided with the fixing device. The present invention relates to a forming apparatus.

  Conventionally, as a fixing device used in a copying machine, a printer, or the like, a fixing member that is provided with a heat source and is rotationally driven or rotationally moved, and a pressure member that is driven by the rotational driving or rotational movement of the fixing member. And fixing the toner image by passing the transfer paper through a nip formed between these members and heating and pressurizing the toner image transferred onto the surface of the transfer paper.

  In this case, a fixing roller that is directly heated by a heat source such as a heater as the fixing member described above and a pressure roller as a pressure member that contacts the fixing roller are provided (hereinafter referred to as “roller / roller system”). In consideration of recent energy savings and shortening of the stabilization time, it is known that a silicone sponge having a heat capacity smaller than that of silicone rubber and higher in thermal insulation is provided as an elastic layer on the core on the pressure roller side. ing.

  In addition, in order to secure a longer nip distance along the transfer paper conveyance direction after reducing the heat capacity than the roller / roller system described above, a heating roller heated by a heat source such as a heater and an elastic layer are provided. The fixing roller and an endless fixing belt that is spanned between the heating roller and the fixing roller and is rotated by the rotational drive of one of the rollers constitute a fixing member, and the fixing roller is in contact with the fixing roller. There is also known a device in which a pressure roller is arranged as a pressure member so as to come into contact (hereinafter referred to as “belt / roller system”).

  Further, contrary to the belt / roller system described above, a fixing roller heated by a heat source such as a heater is used as a fixing member, and an elastic layer is provided to ensure a long nip distance along the transfer paper conveyance direction. A pressure roller, a tension roller that is spaced from the pressure roller, an endless pressure belt that is spanned between the pressure roller and the tension roller and is rotated by the rotation of one of the rollers. Also, there is known a structure in which a pressure member is configured and the pressure roller is disposed so as to contact the fixing roller with the pressure belt interposed therebetween (hereinafter referred to as “roller / belt system”).

  At this time, for the fixing roller and the pressure roller in the belt / roller system, and the pressure roller in the roller / belt system, a silicone sponge or the like is often used as an elastic layer, and the base material of each belt is cost and heat insulation. In view of the above, heat-resistant resins such as polyimide (PI) are often used.

  However, in the case of a roller using a silicone sponge or the like as the elastic layer, if a large pressure is applied to secure the fixing nip, the roller surface side is distorted (depressed) by the elastic force. When left in a high temperature environment for a long time, the surface distortion (dents) is likely to remain more than in the case of a roller using silicone rubber, which causes deformation of the fixing nip portion. There was a problem.

  Such a residual phenomenon of distortion (dent) may also occur in a roller using silicone rubber. However, in the point that the foamed cell collapses to plastic deformation, the case where a silicone sponge is used is used. It was easy to remain. The same deformation can occur for a belt using a heat-resistant resin such as polyimide (PI) as a base material.

  Therefore, in general, a technique for preventing the deformation by shifting the position of the fixing nip portion by driving a roller or a belt at regular time intervals during printing standby is known. Yes.

  In addition, after a certain period of time, a technique for preventing deformation by releasing a pressure contact state between a fixing member such as a fixing roller or a fixing belt and a pressure member such as a pressure roller or a pressure belt and separating them. Is also common.

  However, even if such a technique is adopted, the above-described deformation prevention cannot be coped with when the main power supply of the image forming apparatus is turned off or when the power supply is cut off due to a power failure or the like.

  It should be noted that the deformation of the roller or belt in this case remains once the roller or belt that has risen to a high temperature is cooled in a distorted shape in order to maintain the fixable temperature or return to the early fixing temperature. It can be easily imagined that this phenomenon is unavoidable in a normal configuration due to a phenomenon in which plastic deformation occurs due to stress (baking bending).

  In addition, with respect to such deformation, a belt using a heat-resistant resin such as polyimide (PI) as a base material is stricter than a roller having silicone rubber or silicone sponge as an elastic layer. This is because of plastic deformation of the rigid member.

  Therefore, in order to suppress plastic deformation that occurs after the main power supply is turned off or at the time of a power failure, when the power supply is turned off or a power failure is detected, the pressure contact state between the fixing member and the pressure member is changed by supplying power from the capacitor. There has been proposed a technique for preventing deformation of a roller or a belt by operating a separation mechanism to be released (see, for example, Patent Document 1).

In consideration of limitations such as cost and space, the separation means between the fixing member and the pressure member cannot be used in many cases. Utilizing this, a configuration is adopted in which a roller or belt is driven at regular time intervals to shift the position of the fixing nip portion to prevent deformation.
Japanese Patent Laid-Open No. 2007-041271

  However, in the fixing device and the image forming apparatus configured as described above, for example, in order to shift the position of the fixing nip portion while the roller, the belt, etc. are lowered from the high temperature state to the room temperature state. It is necessary to drive several times. However, if the temperature drops for a short period of time, such as when it is used for a short time, the effect can be achieved even if driving to shift the position of the fixing nip part after the temperature has dropped to room temperature. There was a problem of not being done.

  Conversely, if it takes a long time for the rollers, belts, etc. to drop from a high temperature state to a room temperature state, the drive operation may be terminated before the temperature drops. There arises a problem that the effect is not exhibited.

  It should be noted that even if the power supply capacity of the battery is sufficiently secured and the drive operation is executed frequently, the effect on the deformation can be obtained, but it is not realistic in consideration of the cost of the battery, the charging time, and the like.

  Even if the driving operation is controlled by detecting the temperature of the fixing member, the operation of the control circuit (CPU) is also stopped when the main power is turned off or a power failure occurs. Drive control cannot be performed. In addition, although it is possible to operate the CPU even when the main power supply is turned off or during a power failure using the above-described power storage device, the above-described problem related to the power supply capacity (power storage capacity) is unavoidable.

  Therefore, in consideration of the above circumstances, the present invention has a small storage capacity even if the temperature drop gradient of the fixing member or the pressure member after the main power supply is turned off or during a power failure changes depending on the use state. It is an object of the present invention to provide a fixing device and an image forming apparatus capable of preventing deformation of a fixing member or a pressure member using an inexpensive power storage member.

  The fixing device of the present invention includes a fixing unit that includes a heating unit for fixing an unfixed toner image on a transfer paper, and a pressure unit that is disposed opposite to the fixing unit and conveys the transfer paper through a nip. In the fixing device, a temperature detecting means for detecting the temperature of the fixing means, a heating control means for controlling the output of the heating means based on a temperature detected by the temperature detecting means, and driving the fixing means or the pressure means. From the temperature detecting means when the power supply from the main power supply means is cut off, the power storage means that operates the auxiliary power supply that stores the drive means when the power supply from the main power supply means is interrupted Drive control means for performing drive control of the drive means based on the detected temperature.

  At this time, it is preferable that the power storage unit receives a power supply from the main power supply unit and performs a power storage operation until the temperature reaches a temperature at which the fixing unit can fix.

  Further, after the power supply from the main power supply means is cut off, the drive control means receives the auxiliary power supply from the power storage means and intermittently controls the drive operation interval and the number of times of the drive means. Is preferred.

And a separation unit that releases the pressure contact state between the fixing unit and the pressure unit.
The drive control circuit preferably stops the supply of auxiliary power from the power storage unit to the drive unit when the fixing unit and the pressure unit are separated by the separation unit.

  In addition, the present invention can be an image forming apparatus employing a fixing device having any one of the above-described configurations.

  The fixing device according to the present invention provides an inexpensive power storage member having a small power storage capacity even when the temperature drop gradient of the fixing member or the pressure member changes in accordance with the usage environment, that is, after the main power is turned off or during a power failure. By utilizing this, deformation of the fixing member or the pressure member can be prevented.

  Next, a fixing device and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram of an example of an image forming apparatus provided with a fixing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a main part of the fixing device according to an embodiment of the present invention, and FIG. FIG. 4 is an explanatory diagram of a control example 2 according to an embodiment of the present invention, and FIG. 5 is an explanatory diagram of a control example 3 according to an embodiment of the present invention. .

  As shown in FIG. 1, a printer 1 as an image forming apparatus according to an embodiment of the present invention is connected to a computer or the like (not shown), and generates a full-color image based on image information sent from the computer or the like. Transfer and fix on transfer paper. The right side of the printer 1 is the front side operated by the operator.

(Overall configuration of printer 1)
The printer 1 includes a photoreceptor 2 on which an electrostatic latent image is formed, a rotary developing device main body 3 as a developing unit, a laser unit 4 as an exposure device, and a toner container 5 containing replenishing toner. And a toner replenishing member 6 for supplying replenishing toner contained in the toner container 5 to the rotary developing device main body 3, an intermediate transfer unit 7, a secondary transfer roller 8, and a fixing device 9 as fixing means. Yes.

  On the other hand, a paper feed cassette 10 for storing transfer paper (not shown) is provided at the bottom of the printer 1.

  The transfer paper stored in the paper feed cassette 10 is taken out from the paper feed unit 11 and transported to the transport path 13 leading to the discharge port 12, and the image transfer / fixing process described above is performed in the transport process. The paper feed cassette 10 can be pulled out from the front side of the printer 1 for replacement or replenishment of transfer paper.

  In addition, a manual feed tray 14 that can be tilted is provided on the front surface of the printer 1, and transfer paper can be mounted on the manual feed tray 14. The transfer paper loaded on the manual feed tray 14 is taken out from the manual paper feed unit 15 and joined to the transport path 13, and the image transfer / fixing process described above is performed in the transport process.

  Further, on the upstream side of the secondary transfer roller 8 in the transport path 13, there is a downstream end (front end) of the transfer paper taken out from the paper supply unit 11 or the manual paper supply unit 15 and an intermediate transfer belt 25 described later. A registration roller pair 16 for timing adjustment is provided. Further, on the downstream side of the fixing device 9 in the conveyance path 13, there is a reversing path 17 for reversing and conveying the transfer sheet, which has been fixed on one side for duplex printing, to the upstream side of the conveying path 13 relative to the pair of registration rollers 16. Is provided.

  At this time, the single-side fixed transfer paper for reversal is once transported to the vicinity of the discharge port 12, and then the rear end of the transfer paper is transported to the downstream side of the transport path 13 from the upstream port of the reverse path 17. Then, it is sent to the reverse path 17 by the reverse of the switchback roller 18.

(Configuration of photoconductor 2)
The photosensitive member 2 is rotatably provided in the center of the inside of the printer 1 and its rotation shaft is provided so as to extend in the width direction from the front side of the printer 1, that is, to extend in the depth direction in FIG. Yes. A charging roller 19 for uniformly charging the surface of the photoconductor 2 is provided on the photoconductor 2. Further, a drum cleaning device 20 is provided on the side of the photoconductor 2 to clean the deposits such as toner remaining on the surface of the photoconductor 2.

(Configuration of the rotary developing device body 3)
The rotary developing device main body 3 develops the electrostatic latent image formed on the photoconductor 2 with toner of each color, and is adjacent to the photoconductor 2 and its rotation center is substantially the same as the rotation center of the photoconductor 2. It is arranged to be high. The rotary developing device main body 3 has a cylindrical shape that is rotatable about an axis parallel to the rotation center axis of the photoreceptor 2 and is rotated by a drive system including a motor and gears (not shown). Further, in the present embodiment, the rotary developing device main body 3 is divided into four equal parts and corresponds to toners of four colors (for example, yellow (Y), magenta (M), cyan (C), and black (K)). Two developing devices 21 can be installed.

  Each developing device 21 has substantially the same configuration, and is provided with a developing roller 22 and the like that can be disposed opposite to the photoreceptor 2. Further, each developing device 21 is disposed away from the toner container 5, so that the space for storing toner in the rotary developing device main body 3 is small, and the developing device 21 is downsized. Furthermore, the developing device 21 can be attached to and detached from the rotary developing device main body 3 respectively, and maintenance and replacement of the developing device 21 can be easily performed.

  Each developer 21 has a tip of the toner replenishment member 6 on the outer peripheral surface of the toner case 23 that forms the outer shape of the developer 21 in order to replenish the toner for replenishment from the toner container 5 to the inside of the developer 21. A toner replenishing portion (not shown) made of an elastic material such as rubber having a slit or the like (not shown) is provided.

(Configuration of laser unit 4)
The laser unit 4 scans and exposes the photoconductor 2 based on image information sent from an external computer or the like, and is disposed above the photoconductor 2. The laser unit 4 is provided with known configurations such as a laser light source, a polygon mirror, and a polygon mirror driving motor (not shown). Further, a reflection mirror 24 is provided in front of the laser beam path of the laser unit 4, and the laser light emitted from the laser unit 4 is reflected by the reflection mirror 24 and irradiated onto the surface of the photosensitive member 2. It is like that.

(Configuration of toner container 5)
The toner container 5 stores replenishment toner corresponding to each developing device 21 of the rotary developing device main body 3, and is detachably installed in the printer 1 so as to be replaceable. In addition, the toner container 5 extends from one side surface of the printer 1 to the other side surface (in the depth direction of the paper surface of FIG. 1), respectively, yellow (Y), magenta (M), cyan (C), and black. The four toner containers 5 containing the replenishment toners of the respective colors (K) are independently arranged in parallel.

(Configuration of Toner Supply Member 6)
The toner replenishing member 6 is for supplying the toner of each color stored in the toner container 5 to the corresponding developing device 21, and between the laser unit 4 and the toner container 5 above the photoreceptor 2. Has been placed. Further, the same number of toner replenishing members 6 as the toner containers 5 are arranged so as to be movable in the vertical direction, and each toner replenishing toner is supplied to each developing unit 21 at a position shifted in the depth direction of the paper surface of FIG. The developer 21 can be replenished.

(Configuration of intermediate transfer unit 7)
The intermediate transfer unit 7 sequentially transfers toner images of each color formed on the photoreceptor 2 to an endless intermediate transfer belt 25, and is disposed below the photoreceptor 2 and the toner container 5. The intermediate transfer belt 25 is stretched between a driving roller 26 and driven rollers 27 and 28 that are spaced apart from each other. Further, the portion of the intermediate transfer belt 25 that faces the photoconductor 2 is configured to contact the photoconductor 2 by a temporary transfer roller 29. In the present embodiment, the driven roller 27 has a function of a tension roller for maintaining the tension state of the intermediate transfer belt 25. Further, residual toner after transfer remaining on the surface of the intermediate transfer belt 25 is removed by a belt cleaning device 30 disposed below the rotary developing device main body 3.

  The drive roller 26 is disposed almost directly below the contact portion between the photosensitive member 2 and the rotary developing device main body 3, and the center thereof is located further below the lowermost end of the rotary developing device main body 3. And it drives by the drive system containing the motor and gear which are not shown in figure.

  The driven roller 27 is disposed close to the bottom of the toner container 5 on the front side of the printer 1, and the height thereof is approximately the same as that of the photoreceptor 2.

  The temporary transfer roller 29 is provided below the photoreceptor 2, and a predetermined range of the intermediate transfer belt 25 is in contact with the photoreceptor 2.

(Configuration of secondary transfer roller 8)
The secondary transfer roller 8 is for transferring the toner image transferred to the intermediate transfer belt 25 onto the transfer paper that has been conveyed, and is disposed below the drive roller 26 so as to face the transfer image. The secondary transfer roller 8 is applied with a transfer bias for image transfer to the transfer paper.

(Configuration of Fixing Device 9)
The fixing device 9 heats and presses the toner image transferred on the transfer paper from the front and back of the transfer paper in order to melt and fix the toner image. . The fixing device 9 includes a fixing member 32 that is heated by heat generated by a heating source 31 such as a halogen heater as a heating unit, a pressure member 33 as a pressure unit that comes into pressure contact with the fixing member 32, and a fixing member 32. And a temperature detection sensor 34 as temperature detection means for detecting temperature.

  As shown in FIG. 2, the fixing member 32 includes a cylindrical cored bar 35 made of metal (for example, aluminum, iron, stainless steel, etc.) having a heating source 31 inside, and silicone provided on the surface of the cored bar 35. An elastic layer 36 made of rubber and a release layer 37 made of a PFA tube (or coating) provided on the surface of the elastic layer 36 are provided, and as a whole have a cylindrical roller shape.

  The pressing member 33 includes a cylindrical cored bar 38 and an elastic layer 39 provided on the surface of the cored bar 38, and has a cylindrical roller shape as a whole. The elastic layer 39 may be formed of a plurality of laminated bodies, for example, a low hardness (soft) inner layer and a high hardness (hard) outer layer. Further, the pressing member 33 is separated from the fixing member 32 and the use state in which the pressing member 33 is pressed against the fixing member 32 by a separating means (not shown) such as a lifting mechanism using a solenoid or a rotating mechanism using a link arm. It is also possible to displace to the standby state.

  On the other hand, the temperature detected by the temperature detection sensor 34 is output and monitored by the control circuit 40. The control circuit 40 controls the drive system and the like based on various control programs related to the overall image forming process stored in the ROM 41. The ROM 41 stores a control program related to the fixing device 9 according to the present invention in addition to the various control programs related to the overall image forming process described above. Thus, the control circuit unit 39 and the ROM 41 constitute a microcomputer that executes control of the fixing device 9 according to the present invention.

  Specifically, the control circuit 40 has a control function as a heating control circuit (heating control means) that controls the output of the heating source 31 based on the temperature detected by the temperature detection sensor 34 with respect to the fixing device 9 of the present invention. A control function as a drive control circuit (drive control means) for operating a drive source 42 such as a drive motor for driving the pressure member 33 (or the fixing member 32) at regular time intervals, and a main power source When the power supply from 43 is interrupted, the drive source 42 is driven and controlled using the auxiliary power stored in the battery 44 as the power storage means.

  At this time, as shown in FIGS. 3 to 5, the control circuit 40 receives the auxiliary power supply from the capacitor 44 after the power supply from the main power supply 43 is cut off, and the drive operation interval of the drive source 42. The drive count may be intermittently controlled.

  Note that the control circuit 40 stops the auxiliary power supply from the capacitor 44 to the drive source 42 in a state where the fixing member 32 and the pressure member 33 are separated by the above-described separation means. In addition, the power storage unit 44 receives a power supply from the main power source 43 and performs a power storage operation until the fixing member 32 reaches a temperature at which the fixing member 32 can be fixed.

  Hereinafter, a control example of the control circuit 40 according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 to 5.

  FIG. 3 is a conceptual diagram showing the control operation of the fixing device 9 according to an embodiment of the present invention.

  Here, when the main power source 43 is turned on from the room temperature state and the fixing member 32 is in the READY state (standby state) by the heating of the heating source 31, the main print 43 is executed after two jobs are continuously printed at intervals. The power source 43 is forcibly turned off.

  This state is referred to as (A) state. In the figure, the bold practice indicates the surface temperature of the fixing member 32 (= the temperature detected by the temperature detection sensor 34), and the thick dotted line indicates the surface temperature of the pressure member 33 (detected by another temperature detection sensor not shown).

  From the time when the main power supply 43 is turned on, the electric storage device 44 starts electric storage (charging) and completes the electric storage until the fixing member 32 reaches the READY temperature (standby temperature). Also, the accumulated power supply time when the main power supply 43 is turned on after the main power supply 43 is turned on and the accumulated drive time when the fixing device 9 is driven by the drive source 42 are stored in the RAM 45 or the like at regular intervals. deep.

  The control circuit 40 then turns off the main power supply 43 based on the detected temperature of the temperature detection sensor 34 when the main power supply 43 is turned off, the accumulated power supply time of the main power supply 43, and the accumulated drive time of the drive source 42. Setting of driving at fixed time intervals by supplying power from the capacitor 44, for example, driving operation intervals: t1, t2, t3 and the number of driving operations (for example, three times indicated by a solid circle) are determined.

  At this time, this parameter is set so that the position of the fixing nip portion N is efficiently shifted so that the fixing member 32 has a substantially equal time and temperature interval until the fixing member 32 is lowered from the READY temperature to the room temperature. Set.

  Further, the electric capacity of the battery 44 is not a problem as long as it is used up until it reaches a minimum necessary level, that is, a state where the electric capacity is lowered to room temperature (= the driving operation is completed at regular time intervals). This is because the power storage is completed again when the main power source 43 is turned on from the next room temperature state and the fixing member 32 reaches the READY state.

  Similarly, after the main power source 43 is turned on from the room temperature state and the fixing member 32 is in the READY state, continuous printing is executed for one job, and then the state in which the main power source 43 is turned off is set to the (B) state.

  In this case, the temperature drop gradient after the main power supply 43 is turned off is larger than that in the state (A), but this is dependent on the detected temperature, the integrated power supply time, and the integrated drive time when the main power supply 43 is turned off. Predict and judge, and determine drive operation intervals: t1, t2, t3 and the number of drive operations (for example, three times indicated by dotted circles). Note that t1, t2, and t3 are smaller than in the state (A).

  The same applies to the state (C) in which the main power source 43 is turned on from the room temperature state and the main power source 43 is turned off without performing the printing operation after the fixing member 32 is in the READY state. B) The temperature drop gradient after the main power supply 43 is turned off becomes larger than in the case of the state, but this is determined by the detected temperature, the integrated power supply time, and the integrated drive time when the main power supply 43 is turned off. , Driving operation intervals: t1, t2, t3 and the number of driving operations (for example, three times indicated by dotted circles) are determined. In this case, t1, t2, and t3 are smaller than in the state (B).

  As described above, the detection temperature at the time when the main power supply 43 is turned off, the integrated power supply time, the integrated drive time and the drive operation intervals: t1, t2, and t3 are set to have a proportional relationship, thereby improving the efficiency. The deformation prevention drive can be performed before the temperature is well lowered to room temperature.

  In addition, the state in which the main power supply 43 is turned off from the room temperature state and the main power supply 43 is turned off before the fixing member 32 enters the READY state, that is, in a state where the power storage of the battery 44 is not completed is referred to as a (D) state.

  In this case, as shown in FIG. 4, the detected temperature when the main power supply 43 is turned off is lower than that in the states (A) to (D), and the temperature drop gradient after the main power supply 43 is turned off is growing.

  This is judged based on the detected temperature at the time when the main power supply 43 is turned off, the integrated power supply time, and the integrated drive time, and the drive operation intervals: t1, t2 and the number of drive operations (for example, two times indicated by solid circles) And decide.

  Here, when the main power supply 43 is turned off, the power storage of the battery 44 is not completed, but the number of driving operations is set to two times less than three times in the states (A) to (D). There is no problem with electrical capacity.

  Further, this determination is mainly based on the detected temperature when the main power source 43 is turned off, and since the ultimate temperature itself is lower than the states (A) to (D), in terms of performance of preventing deformation. There is no particular problem.

  Also, after the main power source 43 is turned on from the room temperature state and the fixing member 32 is in the READY state, the main power source 43 is turned on at the same timing as in the state (A) without executing a print job and leaving it for a relatively long time. The state turned off is referred to as (E) state.

  In this case, as shown in FIG. 5, the temperature drop gradient after the main power supply 43 is turned off becomes larger than that in the state (A), but this is the difference in the accumulated drive time when the main power supply 43 is turned off. (A difference from the state (A)) can be determined.

  Here, as described above, the drive operation intervals: t1, t2, t3, and the number of drive operations (for example, three times indicated by dotted circles) are determined. In this case, t1, t2, and t3 are smaller than in the case of the state (A).

  Note that in the case of the fixing device 9 provided with a separation means for the fixing member 32 and the pressure member 33, the deformation of the fixing nip portion basically does not occur in the separated state, and thus the driving operation as in the present invention is not necessary. .

  Therefore, in the case where the fixing device 9 having the separating means for the fixing member 32 and the pressure member 33 adopts the configuration as in the present invention, if the separation state is detected by a switch or the like, the capacitor 44 is detected. It is desirable to suppress the power consumption of the battery 44 by not performing the driving operation at regular time intervals. Further, the power supply from the battery 44 may be physically interrupted when separated.

  As described above, according to the present invention, the pressure member 33 (or the fixing member) after turning off the main power source 43 or at the time of a power failure can be inexpensively and reliably used by using the capacitor 44 having the minimum power source capacity. 32) can be prevented.

[Image forming operation]
In the above configuration, when the printer 1 is turned on (the main power supply 43 is turned on), various parameters are initialized and initial settings such as setting the temperature of the fixing device 9 are executed. When image data is input from a computer or the like connected to the printer 1 and an instruction to start printing is given, an image forming operation is executed as follows.

  During the image forming operation, the toner replenishing member 6 is moved away from the rotary developing device main body 3 to the upper retracted position.

  First, after the photosensitive member 2 is charged by the charging roller 19, scanning exposure corresponding to image data is performed on the photosensitive member 2 by the laser unit 4, and an electrostatic latent image is formed on the photosensitive member 2.

  Next, the rotary developing device main body 3 is rotated so that the corresponding color developing device 21 is opposed to the photosensitive member 2. In this state, the electrostatic latent image on the photoreceptor 2 is developed with the corresponding color toner.

  The developed toner image is transferred to the intermediate transfer belt 25, and a full color image is formed on the intermediate transfer belt 25 by sequentially repeating the above operation for each color. The toner remaining on the photoreceptor 2 is cleaned by the drum cleaning device 20 and discarded in a waste toner container (not shown).

  On the other hand, the transfer paper positioned at the uppermost position of the paper feeding cassette 10 taken out by the paper feeding unit 11 is subjected to the secondary transfer after being matched with the image forming position on the intermediate transfer belt 25 by the registration roller pair 16. It is conveyed to the roller 8.

  Since the secondary transfer roller 8 is in contact with the intermediate transfer belt 25, after the full color toner image formed on the intermediate transfer belt 25 is transferred to the transfer paper by the transfer bias applied to the secondary transfer roller 8. Then, the image is guided to the fixing device 9, and the image is fixed on the transfer paper by heating and pressing by the fixing device 9.

  The fixed transfer paper is directly discharged from the discharge port 12 via the switchback roller 18 in the case of single-sided printing. In the case of duplex printing, the switchback roller 18 switches back to the reverse path 17 and returns to the upstream side of the conveyance path 13 with respect to the registration roller pair 16, and then forms an image on the back side of the transfer paper. Is discharged from the discharge port 12.

(Example 2)
FIG. 6 is a cross-sectional view of an essential part showing Embodiment 2 of the fixing device 9 of the present invention. In the above-described embodiment, the case of the so-called roller / roller type fixing device 9 has been described. However, in the second embodiment, a belt / roller type fixing device 9 ′ is used. In FIG. 6, the same components as those in the above embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

(Configuration of fixing device 9 ')
The fixing device 9 'heats and presses the toner image transferred onto the transfer paper from the front and back of the transfer paper in order to melt and fix the toner image. Yes. Further, the fixing device 9 ′ includes a fixing member 32 ′ that is heated by the heat generated by the heating source 31 such as a halogen heater, a pressure member 33 that is pressed against the fixing member 32 ′, and a temperature that detects the temperature of the fixing member 32 ′. And a detection sensor 34.

  The fixing member 32 ′ includes a cylindrical support roller 46 made of a metal (for example, aluminum, iron, stainless steel, etc.) having a heating source 31 therein, and a core metal 47 and silicone rubber so as to form a pair with the support roller 46. A fixing roller 49 having a two-layer structure with an elastic layer 48 and the like, and a fixing belt 50 straddling the rollers 45 and 48 are provided.

  The pressing member 33 includes a cylindrical cored bar 38 and an elastic layer 39 provided on the surface of the cored bar 38, and has a cylindrical roller shape as a whole. The elastic layer 39 may be formed of a plurality of laminated bodies, for example, a low hardness (soft) inner layer and a high hardness (hard) outer layer. In addition, the pressing member 33 is used in a state in which it is pressed against the fixing member 32 ′ by a separating means (not shown) such as an elevating mechanism using a solenoid or a rotating mechanism using a link arm or the like, and the fixing member 32 ′. It is also possible to displace to a standby state separated from

  Even in the fixing device 9 ′ having such a configuration, the control circuit 40 described above can prevent the pressing member 33 (or the fixing member 32 ′) from being deformed after the main power source 43 is turned off or during a power failure. it can.

(Example 3)
FIG. 7 is a cross-sectional view of an essential part showing Embodiment 3 of the fixing device 9 of the present invention. In the above-described embodiment, the case of the so-called roller / roller type fixing device 9 has been described. However, in this Example 3, the roller / belt type fixing device 9 ″ is used. In FIG. The same reference numerals are given to the same components as those in the embodiment, and the detailed description thereof will be omitted.

(Configuration of fixing device 9 ")
The fixing device 9 ″ heats and presses the front and back surfaces of the transfer paper in order to melt and fix the toner image transferred onto the transfer paper. The fixing device 9 ″ is disposed below the rotary developing device main body 3 and near the back of the printer 1. Further, the fixing device 9 ″ includes a fixing member 32 that is heated by heat generated by a heating source 31 such as a halogen heater, a pressure member 33 ′ that is in pressure contact with the fixing member 32, and a temperature that detects the temperature of the fixing member 32. And a detection sensor 34.

  The fixing member 32 includes a cylindrical cored bar 35 made of metal (for example, aluminum, iron, stainless steel, etc.) having a heating source 31 inside, and an elastic layer 36 made of silicone rubber provided on the surface of the cored bar 35. And a release layer 37 made of a PFA tube (or coating) provided on the surface of the elastic layer 36, and has a cylindrical roller shape as a whole.

  The pressure member 33 ′ includes a cylindrical support roller 51, a pressure roller 54 having a two-layer structure of a core metal 52 and an elastic layer 53 so as to form a pair with the support roller 51, and the rollers 50 and 53. A pressure belt 55 is provided.

  Even in the fixing device 9 ″ having such a configuration, the control circuit 40 described above can prevent the pressure member 33 ′ (or the fixing member 32) from being deformed after the main power source 43 is turned off or during a power failure. it can.

  In the above embodiment, the image forming apparatus of the present invention is applied to a rotary four-color full-color printer. However, for example, a six-color printer or a tandem full-color printer may be used. Needless to say, the present invention can be applied to all image forming apparatuses (particularly, full color) such as a copying machine, a printer, a facsimile machine, or a multi-function machine functionally equipped with these.

1 is an explanatory diagram of an example of an image forming apparatus including a fixing device according to an embodiment of the present disclosure. FIG. 3 is an explanatory diagram of a main part of a fixing device according to an embodiment of the present invention. It is explanatory drawing of the control example 1 which concerns on one Embodiment of this invention. It is explanatory drawing of the control example 2 which concerns on one Embodiment of this invention. It is explanatory drawing of the example 3 of control which concerns on one Embodiment of this invention. It is explanatory drawing of the principal part of Example 2 of the other fixing apparatus which concerns on one Embodiment of this invention. It is explanatory drawing of the principal part of Example 2 of the other fixing apparatus which concerns on one Embodiment of this invention.

Explanation of symbols

1 ... Printer (image forming apparatus)
9: Fixing device (fixing means)
31 ... Heating source (heating means)
33 ... Pressurizing member (pressurizing means)
34. Temperature detection sensor (temperature detection means)
40. Control circuit (heating control means / drive control means)
42 ... Driving source (driving means)
44 ... Accumulator (electric storage means)

Claims (5)

In a fixing device comprising: a fixing unit provided with a heating unit for fixing an unfixed toner image on a transfer paper; and a pressure unit disposed opposite to the fixing unit and nip-conveying the transfer paper.
A temperature detecting means for detecting the temperature of the fixing means; a heating control means for controlling the output of the heating means based on a temperature detected by the temperature detecting means; and a driving means for driving the fixing means or the pressure means. A power storage means for operating the power supply means when the power supply from the main power supply means is cut off, and a temperature detected by the temperature detection means when the power supply from the main power supply means is cut off. And a drive control means for performing drive control of the drive means based on the fixing device.   2. The fixing device according to claim 1, wherein the power storage unit receives a power supply from the main power source and performs a power storage operation until the fixing unit reaches a temperature at which fixing can be performed. .   The drive control means receives the auxiliary power supply from the power storage means after the power supply from the main power supply means is cut off, and intermittently controls the drive operation interval and the number of times of the drive means. The fixing device according to claim 1 or 2. A separation means for releasing the pressure contact state between the fixing means and the pressure means;
The drive control circuit stops auxiliary power supply from the power storage unit to the drive unit in a state where the fixing unit and the pressure unit are separated by the separation unit. The fixing device according to claim 1.   An image forming apparatus comprising the fixing device according to claim 1.

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