JP2004170848A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus which make it possible to securely remove recording paper when the jamming of recording paper occurs and prevent unfixed toner from sticking to the surface of a fixing member, etc. <P>SOLUTION: To remove jammed paper, the knob 71 of the one-way clutch gear 70a of the fixing device is rotated in the direction of the arrow (a) in the case where the recording paper with an unfixed toner held on it has not passed through the nip between a fixing roller 64 and a pressure roll 62. Thus, the paper is moved upstream in the direction of the transport of the recording paper P as a paper ejection gear 69 rotates. By holding the leading end of the recording paper P subjected to fixing, the paper can be removed without soiling a hand. The unfixed toner which has not passed through the nip can also be removed without soiling the surface of the fixing belt 61. In addition, the operation can be performed while checking the condition of the recording paper P is checked. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is used in an image forming apparatus such as a copying machine, a printer, and a facsimile, and relates to a fixing device that fixes an image by heat and pressure while conveying a recording material such as paper, and more particularly, to a fixing device of a belt fixing system, The present invention relates to an image forming apparatus using this.
[0002]
Problems to be solved by the prior art and the invention
2. Description of the Related Art Conventional image forming apparatuses employing an electrophotographic method or an electrostatic recording method, such as a copying machine, a printer, and a facsimile, generally form an electrostatic latent image by exposing the surface of a photosensitive drum to an image. The electrostatic latent image formed on the surface of the body drum is developed by a developing device to form a toner image of a predetermined color, and the toner image is directly transferred and fixed on recording paper, or temporarily on an intermediate transfer member. After the transfer, the image is formed by transferring and fixing the recording paper collectively on the recording paper.
[0003]
By the way, in the image forming apparatus as described above, the recording paper on which the toner image has been transferred is subjected to a fixing process by a fixing device, and is discharged out of the apparatus. When a conveyance failure (referred to as “jam” in this specification) occurs, the image printing operation of the image forming apparatus is automatically interrupted based on a signal from the jam detection unit. At this time, the recording paper may remain in a state where the unfixed toner is held in the nip portion of the fixing device, and it may be necessary to perform a process for recovering this state normally.
[0004]
In such a case, it is necessary to manually remove the jammed paper in the paper feeding unit and the jammed paper that is jammed in the heat fixing unit. The problem at this time is the adhesion of unfixed toner to the fixing member, and many proposals have been made to improve the operability of removal.
[0005]
For example, a device that determines the heater temperature based on the detected temperature of the heating element at the time of reset after a jam and automatically discharges the recording paper (for example, see Patent Document 1), or that automatically stops recording paper conveyance after detecting a jam and discharges the paper automatically (for example, Patent Document 2), when the paper jam occurs on the downstream side of the fixing device, the paper is driven to the upstream side (for example, see Patent Document 3).
Etc. have been proposed.
[0006]
Further, as an apparatus for heating and fixing an image on a recording material of the above-described image forming apparatus, a metal roller (heating roller) which includes a heat source such as a halogen lamp and is maintained at a predetermined temperature, A heat roller method of heating while supporting and transporting a recording material by a pressure roller having a layer and pressing against the heat roller is often used. In addition, various systems such as a flash heating system, an oven heating system, a hot plate heating system, and a high frequency heating system are known.
[0007]
Among them, the heat roller method is such that an electrophotographic fixing device is provided with a heating roller (fixing roller) having a non-adhesive elastic body and a heating source inside, and a pressure roller covered with an elastic body, A heat roller fixing method is used in which the recording paper on which the toner is transferred is passed between the rollers rotating by applying an appropriate pressure to perform fixing.
[0008]
However, in such a heat roller fixing method, since the heat capacity of the heat roller is large, it takes time until the heat roller is heated to a predetermined temperature required for fixing, and a warm-up time (standby time) of the image forming apparatus is required. Causes a problem such as lengthening. Further, since a large amount of power is required to maintain the predetermined temperature, there is a problem that the power consumption of the entire apparatus is significantly increased.
[0009]
Therefore, in recent years, in order to shorten the rise time of the heat roller, a configuration in which the roller is thin has been proposed. However, for example, in a high-speed machine having a high copying speed, it is necessary to increase the nip width in order to obtain the heating time required for fixing, and for that purpose, it is necessary to increase the roller diameter. In some cases, the pressure is increased to increase the amount of collapse of the elastic body of the pressure roller. However, these have limitations, and it is difficult to reduce the diameter and thickness of the roller in order to reduce the heat capacity.
[0010]
Therefore, in recent years, in order to solve these problems, a belt fixing device based on a belt heat fixing method for heating and fixing toner on recording paper on a belt surface has been proposed. In the case of the belt heating fixing method, a heating element having a relatively small heat capacity and a high temperature rise and a thin film belt are used, so that heat energy required for fixing can be obtained only by heating to a predetermined temperature, The standby time can be shortened, and the power consumption can be reduced.
[0011]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-325463 [Patent Document 2]
JP 2001-154527 A [Patent Document 3]
JP-A-2002-189398
[0012]
[Problems to be solved by the invention]
However, the conventional belt heat fixing method has the following problems. In other words, a fixing device having a short standby time has a small heat capacity, and thus heats up rapidly, but has a characteristic that the temperature drops rapidly. Therefore, when the recording paper is in a state where the unfixed toner is held in the nip portion of the fixing device and the recording paper is conveyed in the discharge direction, the unfixed toner is not heated to the fixing temperature, It will adhere to the fixing member. Therefore, a cleaning member for removing unfixed toner is required. This causes the cleaning member to warm up, and is disadvantageous for a fixing device that requires a further reduction in the standby time because heat from a heating source is effectively used only for the fixing member.
[0013]
Further, when a paper jam occurs (paper jam detection), not only the recording paper stays in a normal state, but also, for example, the recording paper is stuck to a member of a fixing device. In some cases, recording paper enters between the separating member and the fixing member without being separated. In this case, as described in the above-mentioned patent document, the operation of automatically discharging and reversing the paper further enters the separation member, deforms due to the rigidity of the recording paper, the separation of the recording material, and the like. May be damaged.
[0014]
In particular, in a fixing device using a belt, the separation of recording paper is a problem. This will be described below. For example, a color heat roller fixing method often employs a self-stripping method. In the self-stripping method, as shown in FIG. 4, the recording paper P is fixed to the fixing roller 55 by using the elasticity of the fixing roller 55 and the stiffness of the recording paper P without using a forced peeling unit such as a peeling claw. This is a peeling method in which the film is naturally peeled from the substrate. In the heat roller fixing method, the behavior due to the elasticity of the fixing roller 55 at the exit of the nip causes a slight deviation between the surface of the fixing roller 55 and the image surface, thereby improving the separability. Therefore, in the heat roller fixing method, since the leading end of the recording paper P coming out of the nip is largely separated from the fixing roller 55, it is easy to separate the recording paper from the fixing roller 55 using the separation claw 87. . In the figure, T is the toner on the recording paper P.
[0015]
However, in the belt fixing method as shown in FIG. 5, since the fixing belt 61 is provided between the fixing roller 64 and the image surface, the self-stripping force of the fixing roller 64 causes the floating of the fixing belt 61 from the fixing roller 64 and the occurrence of floating. The light is absorbed at the exit of the nip due to slippage between the fixing roller 64 and the fixing belt 61, and is hardly transmitted to the image surface. Therefore, the belt fixing method has a smaller separation effect by self-stripping than the heat belt fixing method. In particular, when an image formed with a large amount of toner T is output on the leading end of the recording paper P, the degree of adhesion between the fused toner and the fixing belt 61 increases, and separation becomes difficult.
[0016]
FIG. 5A shows a state 50 in which the fixing belt 61 floats from the fixing roller 64 at the nip exit, and FIG. 5B shows a portion 53 where slippage occurs between the fixing roller 64 and the fixing belt 61.
[0017]
As a result, in the belt fixing device, as shown in FIG. 6, in the case of the recording paper P having a large amount of toner T coming out of the nip at the front end, the recording paper P is hardly separated from the fixing belt 61 and is in close contact therewith. The separation claw 87 does not separate from the fixing belt 61 and may pass through a slight gap of the separation claw 87. As a result, a paper jam may occur due to poor separation. At this time, there is a possibility that the tip of the separation claw 87 falls down to the surface of the fixing belt 61 together with the recording paper P.
[0018]
For this reason, in a fixing device using a belt, there is a problem that the separability of the recording paper is low, and when a jam occurs due to poor separation of the fixing device, the belt is thin and easily broken. If a broken recording paper remains when a paper jam is removed, a paper jam may occur again at the next recording. Further, during continuous recording, the recording material may have already been conveyed to a conveyance path other than the nip portion of the fixing device. Further, when the recording paper is automatically driven to the upstream side in the transport direction as described in Patent Document 3 described above, the recording paper is fed back to the transfer unit, and a recent miniaturized image forming apparatus is required. Since the transport section is short, further paper jams may occur there.
[0019]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In the event that a recording paper jam occurs, the recording paper is reliably removed, and unfixed toner is removed from the surface of the fixing member when the recording paper is removed. It is an object of the present invention to provide a low-cost fixing device that prevents the toner from adhering to the image forming apparatus and has a quick start-up and an image forming apparatus using the fixing device.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, a fixing device according to claim 1 of the present invention has a fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt looped between the fixing roller and the heating roller. The fixing roller is disposed opposite the fixing roller via the fixing belt, and an unfixed image on a recording material is nipped between the fixing belt and the pressing roller, conveyed, and fixed. The fixing device is provided with a manual discharge unit that can manually discharge the recording material only to the upstream side in the transport direction.
[0021]
According to a second aspect of the present invention, in order to achieve the above object, in the fixing device according to the first aspect, the manual discharge unit is connected to a rotation driving unit, and a rotating member rotatable only in the manual discharge direction. It is characterized by having.
[0022]
According to a third aspect of the present invention, there is provided a fixing device according to the first or second aspect, in order to achieve the above object.
[0023]
According to a fourth aspect of the present invention, in order to achieve the above object, a fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt wound around the fixing roller and the heating roller are provided. Then, the pressure roller is disposed opposite to the fixing roller via the fixing belt, and an unfixed image on a recording material is nipped and conveyed between the fixing belt and the pressure roller to fix the image. The image forming apparatus further includes a manual discharge unit that has a fixing device that is detachably attached to the forming apparatus main body, and that can discharge the recording material only to the upstream side in the conveyance direction in conjunction with a processing operation during a jam.
[0024]
According to a fifth aspect of the present invention, in order to achieve the above object, there is provided a fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt looped between the fixing roller and the heating roller. Then, the pressure roller is disposed opposite to the fixing roller via the fixing belt, and an unfixed image on a recording material is nipped and conveyed between the fixing belt and the pressure roller to fix the image. A fixing device detachable from the main body of the image forming apparatus; and a manual discharging means for discharging the recording material only upstream in the conveying direction when the fixing device is detached from the main body of the image forming apparatus. And
[0025]
According to a sixth aspect of the present invention, in order to achieve the above object, the image forming apparatus according to any one of the third to fifth aspects uses an oil-containing toner.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, description will be made by assigning common reference numerals to parts common to the conventional example.
FIG. 1 is a front sectional view (A) showing an outline of a first embodiment of a fixing device according to the present invention, and a side sectional schematic view (B) showing an operation. The fixing device 6 according to the present embodiment is provided so as to face the fixing roller 64 and the heating roller 63, the endless fixing belt 61 wrapped around these rollers 63 and 64, and the fixing roller 64 via the fixing belt 61. And a pressure roller 62 that is pressed against the fixing roller 64 by a pressing unit (not shown). These fixing roller 64, heating roller 63, and pressure roller 62 are rotatably attached to side plates 65a and 65b.
[0027]
The heating roller 63 incorporates a heater (not shown) and is configured as a hollow thin-walled metal roller of aluminum, carbon steel, stainless steel, or the like. More specifically, the surface layer of a core metal such as aluminum, stainless steel, or carbon steel is coated with a heat-resistant release layer (fluorine resin, high release silicon rubber, or the like) so that the releasability from the fixing belt 61 is improved. It is arranged so as to form a downward nip for better performance. The release layer on the surface of the pressure roller 62 has a thickness of less than 7% of the body diameter of the pressure roller 62 and a hardness of 20 Hs or more (JISA).
[0028]
Further, the fixing roller 64 has a core metal in the inner cylindrical portion, and its outer peripheral portion is covered with a heat insulating elastic member (for example, foamed silicon rubber or the like) which is a soft heat resistant material in order to make the nip width sufficiently large. There is as a configuration. The thickness of the fixing roller 64 is set to a sufficient thickness of about 15% to 20% of the diameter of the fixing roller 64.
[0029]
The drive is transmitted to the pressure roller 62 via a gear 68 from a drive gear 66 a of a drive motor 67 constituting a drive unit. That is, the drive motor 67 rotationally drives the drive gear 66a via the shaft 66b, and accordingly, the gear 68 and the pressure roller 62 rotate. Then, the pressurized fixing belt 61 and the fixing roller 64 are driven, and the recording paper P is conveyed and discharged in the direction of arrow p. A paper discharge gear 69 is attached to one side of the pressure roller 62. A one-way clutch gear 70a connected to the paper discharge gear 69 is fixed to a shaft 70b rotatably mounted on the side plate 65b. It is fixed to the end. The one-way clutch gear 70a is rotatable only in the direction of arrow a.
[0030]
In the drawing, reference numerals 87 and 88 denote separation claws, which are attached to the conveyance guide plate to prevent the recording paper P from being wound around the fixing belt 61 and the pressure roller 62. In the figure, reference numeral 86 denotes an oil application roller which rotates in contact with the fixing belt 61 so that a release agent such as silicone oil can be applied on the outer peripheral surface of the fixing belt 61. In the drawing, reference numeral 85 denotes a hollow roller made of aluminum, carbon steel, stainless steel, or the like, which rotates while being in contact with the outer peripheral surface of the pressure roller 62. The hollow roller 85 functions as a cleaning roller for cleaning the surface of the pressure roller 62.
[0031]
When a jam occurs, the paper jam is removed after the driving by the above-described driving units is stopped. First, the cover (not shown) of the image forming apparatus main body is opened, and if the recording paper holding the unfixed toner has not yet passed through the nip between the fixing roller 64 and the pressure roller 62, the knob 71 of the one-way clutch gear 70a of the fixing apparatus is used. Is rotated in the direction of arrow a. At this time, the paper discharge gear 69 rotates in the direction of arrow b, and accordingly the recording paper P in the nip moves in the direction of arrow c to a position where no load is applied. Therefore, it is possible to hold the leading end of the fixed recording paper P, and it is possible to remove the unfixed toner that has not passed through the nip without adhering the operator to the hands and the like without adhering to the surface of the fixing belt 61. Further, since the operation can be performed while checking the state of the recording paper P, breakage of the fixing belt 61, breakage of the recording paper P, and the like can be prevented, and paper jam can be prevented from occurring again at the next recording.
[0032]
FIG. 2 is a sectional view showing an outline of an image forming apparatus according to the present invention using the above-described fixing device. This image forming apparatus has a photosensitive drum 1 as an image carrier for forming an electrostatic latent image corresponding to image information. Examples of the image carrier include an intermediate transfer member and a magnetic image carrier in addition to the photosensitive drum.
[0033]
A charging charger 22 for charging the surface of the photoconductor drum 1 is provided around the photoconductor drum 1, and light image data is applied to the photoconductor drum 1 after the charging process, so that the surface of the photoconductor drum 1 is statically charged. An exposure device (not shown) for forming an electrostatic latent image supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum 1 to visualize the electrostatic latent image to form a toner image on the photosensitive drum 1 Developing unit 20, transfer unit (transfer bias roller 5) for transferring the toner image on photoreceptor drum 1 to recording paper such as copy recording paper
[0034]
Further, the image forming apparatus according to the present embodiment is configured such that the registration rollers 2a and 2b that send out the recording paper fed from a paper feeding unit (not shown) at a predetermined timing, and the recording paper P that is sent out by the registration rollers 2a and 2b. The image forming apparatus includes the transfer belt 3 as a recording paper conveyance body that conveys the paper toward the transfer position, and the above-described fixing device 6 that fixes the toner image on the recording paper P.
[0035]
In such a configuration, the toner image on the photosensitive drum 1 is transferred to the recording paper P conveyed by the transfer belt 3 at a transfer position by charging from the transfer bias roller 5, and thereafter, the transfer paper P is transferred to the transfer belt 3. And the toner image is fixed by the fixing device 6.
[0036]
The transfer belt 3 constitutes one belt unit 80 together with the driving belt driving rollers 4 a and 4 b and the transfer bias roller 5. Further, the belt unit 80 is detachably housed and supported in the case 7, and constitutes the transfer belt unit 100 integrally with the case 7. The fixing unit 6 is supported via a support base 8 that supports these. And the fixing device 6 can be pulled out from the apparatus main body side of the image forming apparatus together with the support table 8 or can be mounted and set in the apparatus main body.
[0037]
The support 8 is provided with a pair of slide rails 15a and 15b, so that the support 8 can be pulled out of the apparatus main body via the slide rails 15a and 15b. Also, two positioning holes 18a and 18b are provided in each of the side plates 10 and 10 (only one side plate is shown in the drawing, but there is a pair parallel to the direction perpendicular to the paper surface of the drawing) of the support base 8. These positioning holes 18a and 18b are provided so that when the support base 8 is completely set in the apparatus main body, the side plate 16 of the apparatus main body (also shown in FIG. Are positioned by the positioning pins 17a and 17b which are formed to protrude.
[0038]
FIGS. 3A and 3B are plan sectional views (A) and (B) showing an outline of a second embodiment of a fixing device according to the present invention, and plan views (C) and (D) of main parts showing operations. The fixing device 6 of the present embodiment is in a state of being fixed to the support 8. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0039]
In the fixing device 6 of the present embodiment, the side plates 65a and 65b are fixed to the support 8. The paper discharge shaft 70c is rotatably supported by the side plates 65a and 65b via a one-way clutch 95. A discharge gear 92 is attached to an end of the drive gear 66a outside the side plate 65a, and a spring 93 is attached between the side plate 65b and the regulating member 91. A regulating member 90 and a knob 71 are fixed outside the side plate 65b. The drive motor 67 of the drive unit, its shaft 66b, and drive gear 66a are attached to an apparatus body (not shown).
[0040]
In a state where the support base 8 is not set on the apparatus main body, that is, in a state where the fixing device 6 does not pass through the driving unit, since the spring 93 presses the side plate 65b, an arrow e is pressed until the regulating member 90 comes into contact with the side plate 65b. Move in the direction. At this time, the paper discharge gear 92 is restricted to a position where it engages with the gear 68. Then, when set in the apparatus main body, the paper discharge gear 92 comes into contact with the regulating member 94 fixed to the apparatus main body between the paper discharge gear 92 and the drive gear 66a, and the paper discharge gear 92 and the paper discharge shaft 70C are pointed by an arrow e. , The paper discharge gear 92 is separated from the gear 68.
[0041]
Therefore, when the transfer belt unit 80 and the fixing device 6 are pulled out of the apparatus main body together with the support table 8 during the jam processing, the sheet ejection gear 92 meshes with the gear 68 and the one-way clutch 95 restricts the rotation in one direction. When the 71 is rotated, the gear 68 and the pressure roller 62 rotate, and the recording paper P in the nip is sent to the transport unit side and removed. Compared with the first embodiment, the transporting unit and the fixing device are simultaneously pulled out, so that the space is widened, and since it is separated from the driving unit, it is easy to rotate and the operability is good.
[0042]
Further, in the present embodiment, the transfer unit, the transporting unit, and the fixing device are movable on a common support. However, only the fixing device may be movable, or may be movable at the same time as the other main body components such as the developing unit. good. Further, in the present embodiment, the direction of removing the recording paper is regulated in conjunction with the release of the fixing device. However, other members constituting the main body device, such as a cover of the main body operated to remove the recording paper in case of a jam. May be linked. Furthermore, in this embodiment, a separate member is provided as a paper discharge shaft in the fixing device. However, the same mechanism can be provided in another shaft member of the fixing device, so that the number of components is reduced, and the cost can be reduced. . In this embodiment, the fixing device is provided with a mechanism for regulating the direction in which the recording paper is removed. However, the present invention is not limited to this example.
[0043]
Further, in the present embodiment, the cleaning member is attached for offsetting the toner. However, the use of the toner containing the oil material improves the releasability from the surface of the fixing member, and a large amount of the toner adheres to the fixing member at the time of a jam. Since the unfixed toner is prevented, a cleaning member is not required. Therefore, the number of members that come into contact with the heated belt is reduced, that is, the capacity of the member to be heated is reduced, so that the rise time is shortened. Further, the cost is reduced because no member is required.
[0044]
【The invention's effect】
As described above, the fixing device according to the first aspect of the present invention allows the recording material in the fixing device to be manually ejected reliably only at the upstream side of the conveyance during the jam processing. It is possible to hold the leading edge of the paper, and it is possible to remove unfixed toner without adhering to the fixing member without soiling the worker. Further, since the operator checks and operates the state of the recording paper, it is possible to prevent breakage of the belt, breakage of the recording material, and the like, and prevent occurrence of a paper jam again at the next recording. Further, since the recording paper can be discharged only in the paper discharge upstream direction in conjunction with the jam processing operation, operability is improved. Further, since the capacity of the member to be heated is reduced, the rise time is shortened, and a fixing device and an image forming apparatus which are advantageous in cost because no member is required can be provided.
[0045]
In the fixing device according to the second aspect, as described above, the recording paper is manually discharged from the fixing unit in the upstream direction of conveyance, so that in addition to the above common effects, the leading end of the fixed recording paper is conveyed by the conveyance unit. Can be removed without the operator having to put his hand or the like.
[0046]
The image forming apparatus according to the third aspect has the same effect as the fixing device according to the first and second aspects.
[0047]
In the image forming apparatus according to the fourth aspect, as described above, when the paper is released from the apparatus main body by the jam processing operation, the paper can be discharged only in the paper discharge upstream direction. Since no work is performed inside the apparatus main body, operability is improved. Further, since the recording material is manually discharged from the fixing unit in the upstream direction of conveyance, unfixed toner does not adhere to the fixing member. Further, since the work can be performed while checking the state, the recording material can be surely removed without breakage of the belt or breakage of the recording material. Further, the leading end of the fixed recording paper is sent to the transport unit, so that the operator can remove the recording paper without fouling the hand.
[0048]
In the image forming apparatus according to the fifth aspect, as described above, when the fixing device is released from the apparatus main body, the sheet can be discharged only in the paper discharge upstream direction. Therefore, operability is improved because no work is performed. In addition, since the recording paper is manually discharged from the fixing unit in the upstream direction of conveyance, unfixed toner does not adhere to the fixing member. Further, since the work can be performed while checking the state, the recording material can be surely removed without breakage of the belt or breakage of the recording material. Further, the leading end of the fixed recording paper is sent to the transport unit, so that the operator can remove the recording paper without fouling the hand.
[0049]
Since the image forming apparatus according to the sixth aspect uses the oil-containing toner as described above, in addition to the above-described common effects, the releasability is improved, and a large amount of unfixed toner is transferred to the fixing member during a jam. Since the adhesion is prevented, a cleaning member is not required, and the capacity of the member that contacts and heats the fixing member is reduced, so that the start-up time is shortened, and the cost is reduced because no member is required.
[Brief description of the drawings]
FIG. 1A is a front sectional view schematically showing a fixing device according to a first embodiment of the present invention, and FIG.
FIG. 2 is a cross-sectional view schematically showing an image forming apparatus according to the present invention using the fixing device of the embodiment shown in FIG.
FIGS. 3A and 3B are plan sectional views (A) and (B) showing an outline of a second embodiment of a fixing device according to the present invention, and plan views (C) and (D) of main parts showing operations.
FIG. 4 is a diagram illustrating a self-stripping method of a fixing device.
FIG. 5 is a diagram illustrating a belt fixing method of a fixing device.
FIG. 6 is a diagram illustrating a problem of a belt fixing method.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 photoconductor drums 2a, 2b registration roller 3 transfer belts 4a, 4b belt drive roller 5 transfer bias roller 6 fixing device 7 case 8 support base 10 support base side plates 15a, 15b slide rail 16 device main body side plates 17a, 17b positioning pins 18a, 18b Positioning hole 20 Developing device 21 Cleaning unit 22 Charging charger 61 Fixing belt 62 Pressure roller 63 Heating roller 64 Fixing rollers 65a, 65b Side plate 66a Drive gear 66b Axis 67 Drive motor 68 Gear 69 Paper discharge gear 70a One-way clutch gear 70b Shaft 70c Discharge shaft 71 Knob 80 Belt unit 85 Hollow roller 86 Oil application rollers 87, 88 Separation claw 91 Regulator 92 Discharge gear 93 Spring 95 One-way clutch 100 Transfer belt unit P Recording paper T Toner

Claims (6)

A fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt wound around the fixing roller and the heating roller, and the pressure roller is connected to the fixing roller via the fixing belt. In a fixing device which is installed to face and fix an unfixed image on a recording material between the fixing belt and the pressure roller, and conveys and fixes the recording material, it is possible to manually discharge the recording material only upstream in the conveyance direction. A fixing device comprising: 2. The fixing device according to claim 1, wherein the manual ejection unit includes a rotating member connected to a rotation driving unit and rotatable only in the manual ejection direction. An image forming apparatus comprising the fixing device according to claim 1. A fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt wound around the fixing roller and the heating roller, and the pressure roller is connected to the fixing roller via the fixing belt. It has a fixing device that is installed to face and fixes an image by fixing and conveying an unfixed image on a recording material between the fixing belt and the pressure roller, and is detachable from the image forming apparatus main body. An image forming apparatus comprising: a manual discharge unit that discharges the recording material only upstream in the conveyance direction in conjunction with the operation. A fixing roller, a heating roller having a heat source for fixing, and an endless fixing belt wound around the fixing roller and the heating roller, and the pressure roller is connected to the fixing roller via the fixing belt. A fixing device that is fixed to the image forming apparatus main body, and is fixed to the image forming apparatus main body. An image forming apparatus, comprising: a manual discharge unit configured to discharge the recording material only upstream in a conveying direction when the recording material is removed from the image forming apparatus main body. 6. An image forming apparatus according to claim 3, wherein an oil-containing toner is used.

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