JP2823733B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device having a first to a third fixing roller, a pressing portion of a first and a second fixing roller, and a pressing portion of a second and a third fixing roller. And an electrophotographic apparatus in which a fixing unit is formed.

[0002]

2. Description of the Related Art A copying machine as an electrophotographic apparatus generally includes a fixing device having a pair of heat rollers, an electrostatic latent image corresponding to a document is formed on a photosensitive member, and a toner image is formed by a developer. After being visualized as, the toner image is transferred onto the sheet, and the sheet is heated and melted and fixed by passing the sheet between the two heat rollers in the fixing device. .

Further, as disclosed in, for example, JP-A-51-98036, a fixing device is provided with three upper, middle, and lower heat rollers, and presses the upper heat roller and the middle heat roller. A first fixing portion is formed by the first fixing portion, and a second fixing portion is formed by a pressing portion between the middle heat roller and the lower heat roller, and the sheet for conveying the sheet to the first and second fixing portions is formed. A device that moves a transport device according to a fixing unit to be used has been proposed.

According to such a configuration, by appropriately selecting the material of the upper, middle, and lower heat rollers, compared to a case where only a pair of heat rollers are provided in the fixing device, paper, paper, It can handle sheets made of various materials such as labels, mylar, and polycarbonate. Then, in the above-mentioned sheet conveying apparatus, the first
The movement to the upper position where the sheet can be conveyed to the fixing unit and the lower position where the sheet can be conveyed to the second fixing unit is performed by rotating the sheet conveying device with its solenoid around the paper input side end. It has become.

However, the solenoid for driving the sheet conveying device between the upper position and the lower position as described above is inevitably large and expensive, which leads to an increase in size and cost of the device. have.

Accordingly, the present inventors have previously provided a fixing device having three heat rollers, and a sheet conveying device for conveying a sheet to the fixing device, using a sheet conveying driving source as a driving source. And Japanese Patent Application No. 4-55325 (hereinafter referred to as Japanese Patent Application No. 4-55325) has proposed a moving part position moving means for moving a sheet conveying moving part of a sheet conveying apparatus to an upper position and a lower position.
No.). As shown in FIG. 5, the suction unit 500 as a sheet conveying device transfers a sheet on which a toner image has been transferred from a photoconductor 408 via a transfer belt 417 to a sheet.
The sheet is conveyed to the fixing device 600. Fixing device 600
Include upper, middle, and lower heat rollers 601 to 603
Are arranged in parallel in the up-down direction, and the suction unit 5 is provided depending on the upper fixing unit or the lower fixing unit to be used.
The sheet conveyance moving unit 521 is moved to an upper position indicated by a two-dot chain line in the drawing or a lower position indicated by a solid line in the drawing.

As shown in FIG. 6, the suction unit 500 includes two transport belts 501 each of which has a drive shaft 5 on the paper input side.
02 and a driven shaft 503 on the paper output side, and is circulated in the direction A, which is the sheet conveyance direction, by the power transmitted from the sheet conveyance drive source (not shown) to the drive shaft 502. . The driven shaft 503 is rotatably attached to a paper output side end of the suction plate 506, and a suction case 507 having a suction fan (not shown) is provided on a lower surface thereof. In addition, the sheet conveyance moving unit 521 is configured by a vertically moving part such as the conveyance belt 501 and the suction plate 506.

The rotation of the drive shaft 502 by the power of the sheet conveyance drive source is controlled by the sprocket 513, the timing belt 514, the sprocket 512, and the idle shaft 51.
1, a gear 515, a spring clutch 516, etc., to be transmitted to the camshaft 509. The rotation of the cam shaft 509 causes the eccentric cams 510, 510, which are in contact with the lower surface of the suction case 507, to rotate, and the sheet transporting section 521 to move up and down.

When the operating portion 517a of the solenoid 517 is engaged with the locking projection 516a of the spring clutch 516, transmission of power to the camshaft 509 is interrupted, and the sheet transporting portion 521 is moved upward. Alternatively, it is held at a lower position. Further, in order to detect the position of the sheet conveyance moving unit 521, as shown in FIG.
23 is provided, and the vertical movement of the sheet conveyance moving unit 521 is controlled in accordance with the detection signals from the upper position sensor 522 and the lower position sensor 523.

With the above configuration, a dedicated driving source for driving the sheet conveying / moving unit 521 is not required, and the size and cost of the apparatus can be reduced.

[0011]

However, in the above configuration, although a driving source dedicated to the sheet transport moving unit 521 is not necessary, the power from the sheet transport driving unit is transmitted, and the sheet transport moving unit 521 is moved up and down. In order to move, the sprocket 513, the timing belt 514, the sprocket 512, the idle shaft 511, the gear 515, the spring clutch 516, the cam shaft 509, the eccentric cams 510 and 50.5.
10, a moving mechanism including a solenoid 517, and the like. Further, an upper position sensor 522, a lower position sensor 523, and the like are required to control the movement of the sheet conveyance moving unit 521. This places a heavy load on the main drive source of the copying machine that also drives the apparatus and the like.

Further, for example, a middle heat roller is provided so as to be able to be separated from and contacted with the upper and lower heat rollers, and is separated from the lower heat roller when the first fixing portion is formed at a pressure contact portion with the upper heat roller. On the other hand, when forming the second fixing portion at the pressure contact portion with the lower heat roller, if the second fixing portion is separated from the upper heat roller, the movement of the middle heat roller for forming the first or second fixing portion is performed. , The sheet transporting section of the sheet transporting device is moved to an upper position or a lower position. However, since the mechanism for driving the middle heat roller and the mechanism for driving the sheet conveyance moving unit are provided separately, a malfunction occurs for some reason, and the position of the middle heat roller and the position of the sheet conveyance moving unit are different. If the positions do not match, a paper jam may occur.

[0013]

According to the present invention, there is provided an electrophotographic apparatus comprising:
A first fixing portion is formed at a pressure contact portion between the first fixing roller and the second fixing roller, and a second fixing portion is formed at a pressure contact portion between the second fixing roller and the third fixing roller. Is formed, and a fixing device for feeding the sheet conveyed to each fixing unit in the discharge direction by rotation of the fixing roller, a first fixing unit sheet conveying position for conveying the sheet on which the toner image has been transferred to the first fixing unit, and a first fixing unit. (2) In an electrophotographic apparatus comprising: a sheet conveying device having a sheet conveying moving unit movably provided at a second fixing unit sheet conveying position for conveying to a fixing unit , wherein the first fixing roller and the third fixing roller are Predetermined
While the second fixing roller is fixed at the position, the second fixing roller is movably provided so as to be able to separate from and contact the first fixing roller and the third fixing roller. The second fixing unit is moved to a first fixing unit position where it is brought into pressure contact with the fixing roller and is separated from the third fixing roller, and a second fixing unit position where it is brought into pressure contact with the third fixing roller and is separated from the first fixing roller. The image forming apparatus further includes a moving unit that moves the sheet conveyance moving unit of the sheet conveyance device to the first fixing unit sheet conveyance position and the second fixing unit sheet conveyance position in conjunction with the movement of the roller.

[0014]

According to the above arrangement, the second fixing roller of the fixing device and the sheet transporting portion of the sheet transporting device move up and down in conjunction with each other by the same moving means. Therefore, it is not necessary to provide a dedicated moving mechanism, a sensor, and the like in order to move the sheet conveying moving unit up and down, and the apparatus can be simplified, and
The load on the main drive source of the device can be reduced.

Further, since the second fixing roller and the sheet conveying / moving section are interlocked with each other, it is possible to avoid a possibility that the positional relation between the second fixing roller and the sheet does not coincide with each other, thereby reducing a possibility of a paper jam.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. A full-color copying machine as an electrophotographic apparatus in the present embodiment (hereinafter simply referred to as a copying machine)
As shown in FIG. 3, an original mounting table 3 made of hard transparent glass is provided on the upper surface of the copying machine main body 1, and an exposure optical system unit 4 is provided below the original mounting table 3. The exposure optical system unit 4 includes a lamp unit 5 that scans a document (not shown) placed on the document table 3 while irradiating light, and a plurality of light units that guide reflected light from the document to the photoconductor 8. Reflecting mirror 6 ...
A lens unit 7 disposed in the optical path of the reflected light.

A charging charger 9 for charging the surface of the photoconductor 8 to a predetermined potential is provided on the outer periphery of the photoconductor 8, and the charging charger 9 further moves from the charging charger 9 in the rotation direction of the photoconductor 8 (the direction of arrow B in the figure). Toward, an inter-image eraser (not shown), a black developing tank 10, a yellow developing tank 11, a magenta developing tank 12, a cyan developing tank 13, and an intermediate transfer device 1
4, a cleaning device 15, and a static elimination device 16 are arranged in this order.

The above-mentioned intermediate transfer device 14 is used to transfer the transfer belt 1
7, rollers 18 and 19 for supporting the transfer belt 17
20, the transfer belt 17 is brought into pressure contact with the photoconductor 8,
A first transfer roller 21 for transferring the toner image formed on the surface to the transfer belt 17, and a second transfer for pressing the toner image on the surface of the transfer belt 17 onto the sheet when the toner image is transferred to the sheet by pressing the roller 20. A roller 22 and a cleaning device 23 for removing residual toner on the surface of the transfer belt 17 are provided.

On the paper supply side of the intermediate transfer device 14, a registration roller 24, a paper supply cassette 25, and a paper supply tray 26 for supplying paper to the intermediate transfer device 14 at a predetermined timing are provided. Near the paper feed tray 25 and the paper feed tray 26, a paper feed roller 27, a transport roller 28, and the like are provided.

In the paper output direction from the intermediate transfer device 14, a suction unit 100 as a sheet transport device for transporting the paper, a fixing device 200 for heating and melting the toner and fixing it on the sheet, a paper discharge roller 30, and a paper discharge roller Paper tray 3
1 is provided.

The above suction unit 100 is shown in FIG.
As shown in FIG. 2, a transport belt 101 is supported by a drive shaft 102 on the paper input side and a driven shaft 103 on the paper output side. Then, the drive shaft 102 is rotated by power transmitted from a belt drive motor 104 described later, so that the transport belt 101 moves around in the direction D in the drawing. Also, the transport belt 101
Alternatively, a sheet transport moving unit 121 is configured by a suction panel (not shown) provided on substantially the same plane as the upper surface of the transport belt 101 and supporting the driven shaft 103. The sheet conveying / moving unit 121 is configured to move up and down around the drive shaft 102 by a moving mechanism (moving means) 300. The moving mechanism 300 will be described later in detail.

In the fixing device 200, an upper heat roller 201 as a first fixing roller, a middle heat roller 202 as a second fixing roller, and a lower heat roller 203 as a third fixing roller are vertically parallel. It is provided in. In the present embodiment, fixing at the time of full-color copying is performed by an upper fixing unit as a first fixing unit formed at a pressure contact portion between the upper heat roller 201 and the middle heat roller 202, while the middle heat roller 202 is The fixing at the time of black and white copying is performed by a lower fixing portion as a second fixing portion formed at a pressure contact portion with the heat roller 203.

Therefore, the surface layer is formed by the upper heat roller 2
01 is formed of silicon rubber, the middle heat roller 202 is formed of Teflon rubber, and the lower heat roller 203 is formed of Teflon rubber or other suitable rubber. Note that the surface of the upper heat roller 201 is a very smooth surface in order to obtain high releasability from a three-layer toner image for obtaining a full-color image.

Each of the heat rollers 201 to 203 has a hollow shape, and a heater lamp 204 for heating is provided in the hollow portion. Around the heat rollers 201 to 203, a thermistor 205 for detecting the surface temperature of the heat rollers, a thermostat (not shown) incorporated in a circuit of the heater lamp 204, toner attached to the surfaces of the heat rollers 201 to 203, and the like are provided. A cleaning roller 206 to be removed is provided. Also, the middle and lower heat rollers 202
A separation claw 207 that separates the paper from the roller surface is provided around the upper heat roller 201.
Is provided with an oil application roller 208 impregnated with silicon oil.

The oil application roller 208 applies silicone oil to the surface of the upper heat roller 201 to prevent color toner from adhering to the surface of the heat roller, that is, to prevent offset, thereby ensuring the releasability of the color toner image. , For imparting gloss to a full-color copy image. When the upper fixing unit is used, the oil applying roller 208 is pressed against the upper heat roller 201 by an oil applying roller driving mechanism 211 described later.

The upper and lower heat rollers 201 to 2
03, the middle heat roller 202 is driven, and the upper and lower heat rollers 201 and 203 are driven. The middle heat roller 202 is driven by a heat roller drive motor 212 described later, and is used for a fixing unit to be used. It is designed to reverse according to the direction.

In this embodiment, the upper heat roller 20
1 and the lower heat roller 203 are fixedly attached to a frame 209 of the fixing device 200. The middle heat roller 202 is provided at the upper fixing unit position forming the upper fixing unit and the lower fixing unit position forming the lower fixing unit so as to be vertically movable by the moving mechanism 300. When the lower fixing portion is formed, the upper heat roller 201 is separated from the upper heat roller 201 while being pressed against the upper heat roller 201 and separated from the lower heat roller 203.

The moving mechanism 300 includes the upper and lower arms 30.
1, an arm fulcrum 302, a link pin 303, a tension spring 304, a lift cam 305, an upper position sensor 306, a lower position sensor 307, and the like. One end of the upper and lower arms 301 is rotatably attached to the frame 209 by an arm fulcrum 302. At the other end of the upper and lower arms 301, a sheet conveying / moving unit 121 of the suction unit 100 is held by a link pin 303, and at a substantially central portion, a middle heat roller 202 is held via a bearing 210. The link pin 303 has a tension spring 30 for urging the upper and lower arms 301 downward.
The extension spring 304 allows the link cam 305 to contact the lower surface of the upper and lower arms 301.

The link cam 305 receives a driving force from a link cam drive mechanism 308, which will be described later, and rotates to move the upper and lower arms 301 up and down. Accordingly, the middle heat roller 202 moves to the upper fixing unit position and the lower fixing unit position, and the upper position (first fixing unit conveying position) and the lower fixing unit where the sheet conveying moving unit 121 conveys the sheet to the upper fixing unit. Is moved to a lower position (second fixing unit transport position) for transporting the sheet to the second position. Further, near the upper and lower arm fulcrum 302, an upper position sensor 306 for detecting the arrival of the upper and lower arms 301 at the upper position and a lower position sensor 307 for detecting the arrival at the lower position of the upper and lower arms 301 are provided.

Further, as shown in FIG.
A control device 41 is provided as control means for controlling the suction unit 100 and the fixing device 200. The control device 41, based on inputs from the upper position sensor 306, the lower position sensor 307, the thermistor 205, and other various input keys, as described later, controls the heat roller drive motor 212, the belt drive motor 104, the heater lamp The operation of the 204, the oil application roller drive mechanism 211, the link cam drive mechanism 308, and the like is controlled.

In the above configuration, when the copy start button is turned on after the full color copy selection key is turned on, the link cam 305 is controlled by the control device 41.
Are driven by the link cam drive mechanism 308, as shown in FIG. 1, the upper and lower arms 301 move to the upper position, the middle heat roller 202 moves to the upper fixing unit position, and the pressure contact portion with the upper heat roller 201 moves. To form an upper fixing section for full-color copying, and the sheet conveying / moving section 121 is held at an upper position.

Further, the middle heat roller 202 is driven by the heat roller driving motor 212 to rotate in the counterclockwise direction, and accordingly, the upper heat roller 201 rotates in the clockwise direction. The oil application roller 208 is pressed against the upper heat roller 201 by the oil application roller drive mechanism 215 described above. The upper heat roller 201
The operation of pressing the oil application roller 208 against the sheet may be performed at an appropriate time before the sheet is conveyed to the upper fixing unit. In addition, lighting or extinguishing of the heater lamp 204 in each heat roller 201/202 is controlled in accordance with the surface temperature of the upper and middle heat rollers 201/202 detected by the thermistor 205. The temperature is adjusted to a predetermined temperature.

The full-color copy mode has a copy cycle in which yellow, magenta, and cyan are developed and transferred to the transfer belt 17 shown in FIG. 3, respectively. When the operation is completed, first, a yellow copy cycle is executed.

First, the surface of the photoconductor 8 rotating in the B direction is uniformly charged by the charging charger 9, and the first scanning of the original on the original table 3 is performed by the exposure optical system 4. Light reflected from the original is exposed to the surface of the photoconductor 8 between the charging charger 9 and the inter-image eraser (not shown) via a blue color separation filter (not shown) and a slit (not shown). The point is irradiated to expose the photoreceptor 8 to form an electrostatic latent image. Next, the potential of the non-image area on the photoreceptor 8 is removed by an inter-image eraser.
1 to form a yellow toner image.
Next, the yellow toner image on the surface of the photoreceptor 8 is transferred to the transfer belt 17 moving in the C direction by the first transfer roller 21 to which a negative high voltage is applied. The residual toner on the surface of the photoconductor 8 is removed by the cleaning device 15, and the residual potential on the surface of the photoconductor 8 is removed by the charge removing device 16.

When the above-described series of operations is completed, the photosensitive member 8 is charged again by the charging charger 9, and the original is scanned by the exposure optical system 4 for the second time. In this case, a green color separation filter is used, and the electrostatic latent image formed on the photoconductor 8 is developed with magenta toner in the magenta developing tank 12. The magenta toner image formed on the surface of the photoconductor 8 is transferred by the first transfer roller 21 so as to be superimposed on the previous yellow toner image on the transfer belt 17. Thereafter, similarly, the third scanning by the exposure optical system unit 4 using the red color separation filter is performed, and the cyan toner image is developed on the photoconductor 8 by the development with the cyan toner in the cyan developing tank 13. It is formed. This cyan toner image is transferred onto the magenta toner image on the transfer belt 17.

Next, the second transfer roller 22, which has been separated from the transfer belt 17 in the operation so far, is
7, and a negative voltage higher than the surface potential of the transfer belt 17 is applied to the second transfer roller 22, so that the second transfer roller 22 is conveyed from the sheet cassette 25 or the sheet tray 26 via the registration roller 24. The three-layer toner image on the transfer belt 17 is transferred to the paper.

The sheet on which the toner image has been transferred is conveyed by the conveyor belt 101 of the suction unit 100 to an upper fixing section formed at a press contact portion between the upper heat roller 201 and the middle heat roller 202. In the upper fixing section, the three-layer color toner image on the paper is heated and melted by the upper and middle heat rollers 201 and 202, and is fixed on the paper. At this time, since silicon oil is supplied from the oil application roller 208 to the upper heat roller 201, offset of the toner image to the upper heat roller 201 is prevented, and gloss is given to the full-color toner image on the paper. You.

Next, the sheet discharged from the fixing device 200 is discharged onto a discharge tray 31 by a discharge roller 30.

Next, the black-and-white copying operation of the copying machine will be described. When the copy start button is turned on after the black-and-white copy selection key (not shown) is turned on from the state where the full-color copy is possible, the link cam 305 is driven by the link cam drive mechanism 308 under the control of the control device 41.
The upper and lower arms 301 are moved to the lower position as shown in FIG.
2 moves to the lower fixing unit position to form a lower fixing unit for black-and-white copying at a pressure contact portion with the lower heat roller 203, and
The sheet conveying / moving unit 121 moves to the lower position and is held.

Then, the middle heat roller 202 is rotated clockwise by the heat roller drive motor 212,
The lower heat roller 203 rotates counterclockwise. The oil application roller 208 is separated from the upper heat roller 201. In addition, according to the surface temperatures of the middle and lower heat rollers 202 and 203 detected by the thermistor 205, the lighting of the heater lamp 204 in each of the heat rollers 202 and 203 is controlled, and both heat rollers 202 and 203 are set to a predetermined setting. Adjust to temperature.

Thereafter, the surface of the photosensitive member 8 is uniformly charged by the charging charger 9 and the exposure optical system 4 scans the original on the original placing table 3. The reflected light from the original is guided to the exposure optical system unit 4 without passing through the color separation filter and the slit, and is irradiated on the photoconductor 8.
An electrostatic latent image is formed on the image. Thereafter, the above-described electrostatic latent image is developed by the black developing tank 10, and the black toner image thus formed is transferred to the transfer belt 17 and further transferred to paper.

The sheet on which the toner image has been transferred is conveyed by a conveying belt 101 of the suction unit 100 to a lower fixing section formed at a press contact portion between the middle heat roller 202 and the lower heat roller 203, and the toner image is transferred to the sheet. Settled on top. Thereafter, the sheet discharged from the fixing device 200 is discharged onto a discharge tray 31 by a discharge roller 30.

As described above, the copying machine has the moving mechanism 30
0, the middle heat roller 202 in the fixing device 200
And the sheet transport moving unit 12 of the suction unit 100
1 is linked. Therefore, the number of components such as the drive system and the sensors can be reduced as compared with the case where the middle heat roller 202 and the sheet conveying / moving unit 121 are separately driven, and the main drive source of the copying machine main body can be reduced. Such a load can be reduced, and a malfunction does not occur in the positional relationship between the middle heat roller 202 and the sheet conveyance moving unit 121, and the occurrence of a paper jam or the like is reduced.

In this embodiment, the link cam 305 is brought into contact with the lower side of the upper / lower arm 301 for moving the middle heat roller 202 and the sheet conveying / moving section 121, and the tension for urging the upper / lower arm 301 downward. Spring 3
04 was provided and the vertical arm 301 was moved up and down.
For example, the present invention is also applicable to a case where a link cam is provided so as to be in contact with the upper surface of the upper and lower arms 301 and a tension spring for urging the upper and lower arms 301 upward is provided to perform vertical movement of the upper and lower arms 301. Applicable.

[0045]

As described above, in the electrophotographic apparatus of the present invention, the first fixing roller and the third fixing roller are located at predetermined positions.
While provided are fixed, the second fixing roller, disjunction relative to the first fixing roller and the third fixing roller
The first fixing roller is movably provided in such a manner that the second fixing roller is brought into pressure contact with the first fixing roller to be separated from the third fixing roller.
The sheet is conveyed by the sheet conveying device to a fixing unit position and to a second fixing unit position to be brought into pressure contact with the third fixing roller to be separated from the first fixing roller, and to interlock with the moving operation of the second fixing roller. The moving unit moves the moving unit to the first fixing unit sheet conveying position and the second fixing unit sheet conveying position.

Therefore, it is not necessary to provide a dedicated moving mechanism, a sensor, and the like for vertically moving the sheet conveying moving unit, so that the apparatus can be simplified and the load on the main drive source of the apparatus can be reduced. In addition, since the second fixing roller and the sheet conveyance moving unit are linked, it is possible to avoid a possibility that a malfunction in which these positional relations do not coincide with each other may occur, thereby reducing an effect of reducing a paper jam. Play.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a positional relationship between upper, middle, and lower heat rollers and a suction unit in a fixing device during full-color copying in a copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing a state during black-and-white copying in the configuration shown in FIG. 1;

FIG. 3 is an overall configuration diagram showing the copying machine.

FIG. 4 is a block diagram showing a main configuration of a control system provided in the copying machine.

FIG. 5 is an enlarged view of a main part showing an internal structure of a conventional copying machine.

FIG. 6 is a perspective view of a suction unit provided in a conventional copying machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 suction unit (sheet conveying device) 121 sheet conveying moving unit 200 fixing device 201 upper heat roller (first fixing roller) 202 middle heat roller (second fixing roller) 203 lower heat roller (third fixing roller) 300 moving mechanism ( transportation)

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yasunori Kawai 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-51-98036 (JP, A) JP-A-2 -126271 (JP, A) Japanese Utility Model Showa 60-159463 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 13/20 G03G 15/20

Claims (1)

(57) [Claims] A first fixing roller provided between the first fixing roller and the second fixing roller;
A fixing device in which a fixing portion is formed, and a second fixing portion is formed in a pressure contact portion between the second fixing roller and the third fixing roller, and the sheet conveyed to each fixing portion is fed in a discharge direction by rotation of the fixing roller. And a sheet transport moving unit movably provided at a first fixing unit sheet transport position for transporting the sheet onto which the toner image has been transferred to the first fixing unit and a second fixing unit sheet transport position for transporting the sheet to the second fixing unit. The first fixing roller and the third fixing roller are positioned at predetermined positions.
And the second fixing roller is movably provided so as to be able to be separated from and contacted with the first fixing roller and the third fixing roller. A second fixing unit which moves to a first fixing unit position where it is in pressure contact with the roller and is separated from the third fixing roller, and a second fixing unit position where it is in pressure contact with the third fixing roller and is separated from the first fixing roller; An electrophotographic apparatus, comprising: a moving unit that moves a sheet conveying moving unit of the sheet conveying device to a first fixing unit sheet conveying position and a second fixing unit sheet conveying position in conjunction with the moving operation of the sheet conveying device.