JPH09190031A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate a jamming processing by arranging a frame so that the frame can be turned taking one end side of a transfer paper in a carrying direction as a fulcrum and supporting a transfer unit so that the other end side opposite to that of the frame as a fulcrum. SOLUTION: Recessed parts 381 for moving a transfer unit 350 downward are respectively formed on confronted erect parts of the frame 380, and the transfer unit 350 is arranged across the confronted erect parts with the recessed parts 381 formed, and the transfer unit 350 is rotatably supported on the other end side opposite to one end side of a transfer paper carrying direction as the rotating fulcrum of the frame 380. And, between the frame 380 and the main body frame 390, the device is provided with a moving means 391 for moving the transfer unit 350 between the position confronted with the photoreceptor drum 31 and the lower position of the photoreceptor drum 31 by turning the frame with the central axis 453 as the fulcrum, and a fixing means 392 for fixing the transfer unit 350 at a position facing the photoreceptor drum 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, and more particularly to an image forming apparatus having a photosensitive drum.

[0002]

2. Description of the Related Art Generally, an image forming apparatus such as a copying machine comprises an optical mechanism, an image forming section having a photosensitive drum, a sheet conveying section and the like. In such an image forming apparatus, an electrostatic latent image is formed by exposing a document image in the electrostatic latent image forming portion of a charged photoconductor drum, and the electrostatic latent image appears as a toner image in the developing portion. Be converted. And
The original image is transferred onto the transfer paper at the transfer unit provided with the transfer unit. The transfer sheet onto which the original image has been transferred is separated from the photosensitive drum in the separating section, and is fed to the fixing section by the conveying unit, where the fixing process is performed. The transfer unit and the transport unit are usually fixed to the same frame.

In the image forming apparatus as described above, when a jam (paper jam) occurs around the photosensitive drum,
Jam processing (processing for removing jammed transfer paper) is performed as follows. That is, the transfer unit is separated from the photosensitive drum by operating a lever attached to the side portion of the frame to which the transfer unit and the transport unit are fixed, and lowering one end side of the frame to form the transfer unit from the photosensitive drum. The transfer paper that causes the jam is pulled out from the gap.

[0004]

However, in the above-mentioned conventional image forming apparatus, since other constituent members are arranged at the lower position of the frame where the transfer unit and the transport unit are fixed, the cause of the jam occurs. However, there is a problem in that the frame cannot be lowered by a distance that forms a gap that allows the transfer sheet to be easily pulled out, and as a result, the jam processing operation becomes complicated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus which can easily perform jam processing.

[0006]

In order to achieve such an object, an image forming apparatus according to a first aspect of the present invention comprises a transfer unit for transferring an original image onto a transfer sheet in a transfer area of a photosensitive drum, and an image forming apparatus for transferring the original image. A transport unit that transports the transferred transfer paper to the fixing unit, a frame that supports the transfer unit and the transport unit, and is rotatably disposed with one end side of the transfer paper in the transport direction as a fulcrum. Moving means for moving the transfer unit between a position facing the photoconductor drum and a lower position separated from the photoconductor drum by rotating the frame about the fulcrum,
Fixing means for fixing the transfer unit to the facing position when the transfer unit is moved to the facing position of the photoconductor drum, the transfer unit supporting the other end side opposite to the one end side as a fulcrum. Is rotatably supported by the frame.

In the image forming apparatus according to the first aspect of the present invention, the frame is rotatably disposed with one end side of the transfer sheet conveyance direction as a fulcrum, and the transfer unit has the other end side opposite to the frame as a fulcrum. Since the frame is rotatably supported, when the other end side of the frame moves downward with the one end side as a fulcrum, one end side of the transfer unit moves downward with the other end side as a fulcrum. As a result, the gap between the transfer unit and the photoconductor drum is expanded as compared with the case where the transfer unit is fixed to the frame.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the transport unit is fixed to and supported by a frame, and the transfer unit is a lower portion separated from the photosensitive drum. When moved to a position, the upper surface of the transfer unit is rotatable to a position lower than the transfer sheet transfer surface of the transfer unit.

In the image forming apparatus according to the second aspect, when the transfer unit is moved to the lower position separated from the photosensitive drum, the transfer unit is rotated and the upper surface of the transfer unit is the transfer surface of the transfer unit. It will be moved to a lower position.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the moving means includes a rotating shaft, and an arm extending radially from the rotating shaft.
It is characterized in that it is constituted by a roller attached to the tip of this arm and capable of contacting the bottom surface of the frame.

In the image forming apparatus according to the third aspect of the present invention, when the transfer unit is moved from the lower position of the photosensitive drum to the facing position of the photosensitive drum, the rotary shaft is rotated to contact the bottom surface of the frame. The frame is lifted by moving the rollers upward along the circumference around the rotation axis. When the transfer unit is moved from the position facing the photoconductor drum to the position below the photoconductor drum, the rotation shaft is rotated in the direction opposite to the above direction so that the roller abutting on the bottom surface of the frame is moved to the above circumference. The frame is lowered by its own weight by moving it downward.

An image forming apparatus according to a fourth aspect of the present invention is the image forming apparatus according to the third aspect, wherein the fixing means is provided with the rotary shaft and the radial direction extending from the rotary shaft and the transfer means. It is characterized in that it is composed of a cam that can come into contact with the bottom surface of the unit.

In the image forming apparatus according to the fourth aspect, when the rotation shaft is rotated and the roller lifts the frame, the cam is simultaneously moved, and when the transfer unit is moved to the position facing the photosensitive drum, The peripheral surface portion farthest from the rotation axis of the cam comes into contact with the bottom surface of the transfer unit to fix the transfer unit at the position facing the photosensitive drum.

An image forming apparatus according to a fifth aspect is the image forming apparatus according to the third or fourth aspect, characterized in that the frame is provided with an elastic member at a position where the roller abuts.

In the image forming apparatus according to the fifth aspect of the present invention, since the roller is brought into contact with the bottom surface of the frame through the elastic member, the transfer unit is prevented from being pressed against the photosensitive drum by an unnecessarily large force. .

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the transfer unit is supported by the wire support portion and the frame, and the wire support is provided. It is characterized in that it is constituted by an insulating holding portion for holding the portion insulatively, and an elastic member interposed between the wire supporting portion and the insulating holding portion.

In the image forming apparatus according to the sixth aspect, when the transfer unit is pressed from the bottom surface side and fixed at the position facing the photosensitive drum, the excessive pressing force is absorbed by the elastic member, and the transfer unit is It will not be pressed against the photosensitive drum side by a force larger than necessary.

[0018]

1 is an overall perspective view showing an embodiment of a copying machine according to the present invention, and FIG. 2 is an internal configuration diagram thereof. The copying machine 1 comprises a copying machine body 1a and a document placing portion 1b arranged on the top of the copying machine body 1a.
The image forming unit 3 includes the optical mechanism 2, the photoconductor drum 31, the sheet conveying mechanism 4, the reversing mechanism 5, and the double-sided unit unit 6.

The original document placing portion 1b is an original document holding portion for opening and closing the surface of the contact glass 1c attached to the top opening of the copying machine main body 1a, and an original is set manually. As the document placing section 1b,
It is also possible to use an automatic document feeder which is an upper part of the contact glass 1c and carries the stacked originals one by one onto the contact glass 1c, sets them at the exposure position, and carries them out after reading the originals.

The optical mechanism 2 includes a contact glass 1c.
The upper manuscript is the home position H. A first optical system 21 having a light source 211 consisting of a halogen lamp that scans in the forward movement based on P and a reflecting mirror 212, and a plurality of reflections for guiding the document image irradiated by the light source 211 and reflected on the document surface to the image forming section 3. A second optical system 22 having mirrors 221, 222, a lens 23 for forming the original image on the surface of the photosensitive drum 31,
A pair of guide rails 24 that guide the first and second optical systems 21 and 22 in the reciprocating direction (indicated by arrows in FIG. 2), and the first and second optical systems 21 and 22 along the guide rails 24. Each of them is provided with driving means (not shown) for traveling at a predetermined speed. The reflecting mirror 223 guides the original image that has passed through the lens 23 to the exposure position of the photosensitive drum 31.

The light from the light source 211 is applied to the document set on the contact glass 1c and reflected on the document surface to obtain a document image. This original image is reflected by the reflecting mirrors 212, 221, 222 as shown by the one-dot chain line in the figure, passes through the lens 23, and is guided to the exposure position of the photosensitive drum 31 via the reflecting mirror 223.

The image forming section 3 is provided with a photosensitive drum 31 which is rotated at a constant speed in the clockwise direction by a drive means (not shown), and the main charging section 32 is provided around the photosensitive drum 31 from the upstream side in the rotating direction. , Developing unit 33, toner collecting roller unit 34, transfer unit 35, separating unit 36 and cleaning unit 3
7 is provided. The surface of the photosensitive drum 31 is uniformly charged by the main charging unit 32, and then the original image is exposed to form an electrostatic latent image. This electrostatic latent image is made visible by the toner attached to the developing unit 33, and then the transfer unit 3
5 is transferred to the transfer paper. The transfer paper on which the toner image has been transferred is separated from the photosensitive drum 31 by the separation unit 36,
It is guided to the fixing unit 46 described later.

The paper transport mechanism 4 is detachably provided at a lower position of the main body 1a of the copying machine, and is provided with a plurality of paper feed cassettes C for accommodating transfer papers of a predetermined size in a stacked state. Paper feed rollers 411 and 412 for feeding the transfer paper one by one from the paper, separation roller pairs 421 and 422 for preventing the double feed of the fed paper, conveying roller pairs 431 to 434, and registration rollers for secondary paper feed It comprises a pair 44. Further, in the downstream direction of the photoconductor drum 31, a conveying belt 45 stretched between a pair of rotating rollers 451 and 452, a fixing unit 46, a discharge roller pair 47, and a discharge tray 48 are provided. Transport guide section 40
Is for transporting the sheet fed from the separating roller pair 42 to the discharging roller pair 47, and is composed of plate-shaped members having a required width and arranged to face each other. Bypass tray 4
Reference numeral 9 denotes a sheet on which a transfer sheet of a required size can be manually set. The sheet 9 has a sheet feeding roller 413 and a separating roller pair 423, and joins the conveyance guide section 40 on the downstream side. The fixing unit 46 includes an upper heat roller 461 and a lower pressure roller 462. The heat roller 461 is provided with a heater inside, and the pressure roller 462 is pressed against the heat roller 461 side with a required pressure.

Paper feed cassette C or manual feed tray 4
The transfer paper fed from the paper feeding rollers 411 to 413 from the sheet 9 is fed to the registration roller pair 44 via the respective conveying roller pairs 431 to 434. The transfer sheet conveyed to the registration roller pair 44 is secondarily fed in synchronization with the exposure scanning start timing of the optical mechanism 2, and is transferred to the transfer unit 3.
At 5, the toner image is transferred. The transfer sheet onto which the toner image has been transferred is conveyed to the fixing unit 46 via the conveying belt 45, where the toner image is fixed on the transfer sheet, and then the discharging roller pair 4
After that, the sheet is discharged to the sheet discharge tray 48.

The reversing mechanism 5 is located in the middle of the conveyance guide section 40 between the fixing section 46 and the discharge roller pair 47, and the transfer sheet is discharged around the horizontal shaft 511 by an electromagnetic solenoid (not shown). Has a direction switching plate 51 that can be switched between a rotation position for guiding in the direction and a rotation position for guiding in the direction of the double-sided unit section 6 which will be described later. The reverse sheet guide 52, the transport roller pair 53 in the middle of the reverse sheet guide 52, and the carry-out roller pair 54 provided at the downstream end of the reverse sheet guide 52. The transfer sheet whose direction has been switched to the duplex unit 6 side is conveyed downward along the reverse sheet guide 52, and the fixing portion is formed in the curved portion formed in the portion of the reverse sheet guide 52 where the pair of conveying rollers 53 is provided. The curl formed by 46 is corrected, and the carry-out roller pair 54 is returned with the curl formed as straight as possible.
It is led to.

The double-sided unit section 6 is for copying on both sides of a transfer sheet, and is composed of an intermediate tray section 7 having a unit section body 60 and a re-feeding mechanism 8. The intermediate tray section 7 is provided with an intermediate tray 71 on which the inverted transfer paper is placed, and above the paper tray 7
2, a nip roller 73, a paper guide 74, and a rotating plate 75 that falls by its own weight on the paper surface and rotates together with the paper as it is transported. The paper guide 74 is the rotary plate 7.
No. 5, which is provided only on the front side of the mounting position, is pivotally supported at the upper part, and is tilted rearward by its own weight or slightly biased downward to abut on the intermediate tray 71. The transfer paper carried out from the intermediate tray 71
Smoothly guide it to the surface of the rotating plate 7
It prevents stock mistakes caused by collision with 5.

Further, the re-feeding mechanism 8 has a re-feeding guide portion 81 which is formed below the intermediate tray 71 and which is a plate-like member and is opposed to the intermediate tray 71 at a predetermined interval. The re-feeding roller 82, which is located slightly on the front side in the re-feeding direction and whose upper peripheral surface is partially exposed, the reversing roller 83 in front of it, and the pair of rotating rollers 841 and 842.
The separation belt 84 which is stretched in between and rotates in a direction opposite to the re-feeding direction while being in contact with the peripheral surface of the reversing roller 83, and the re-feeding guide portion 81 are arranged at appropriate positions with a required interval. The re-feeding roller pairs 851 to 853 are formed. Further, at the sheet nip position where the rotating roller 841 of the separating belt 84 and the reversing roller 83 face each other, a flexible sheet body 86 hangs downward from the unit main body 60, and its lower end abuts on the reversing roller 83. It is attached in contact.

It should be noted that the duplex unit 6 is the main body of the copying machine 1.
It is configured so that it can be pulled out to the front side from a, and a paper feed cassette C is slid from the front side instead of the double-sided unit at this mounting position, and a three-stage structure of the paper feed cassette can also be formed. It is possible. In this case, a portion corresponding to the sheet feeding roller 411 and the separating roller pair 421 may be configured as a feeding unit, and the feeding unit may be loaded prior to the insertion of the sheet feeding cassette C.

When the transfer paper is sent from the carry-out roller pair 54 onto the intermediate tray 71, the paper knocking section 72 rotates and presses the rear end side (the front end side when re-feeding) of the transfer paper from above. The remaining curl is forcibly regulated straight, and in this state, the nip roller 73 rotates in the sheet re-feeding direction to transfer the transfer sheet to the sheet nip position between the reversing roller 83 and the sheet body 86 to secure the nip state. And align the front edge. The transfer state of the transfer sheet is monitored by a rotary encoder (not shown) or the like provided on the rotary shaft of the rotary plate 75. In this state, when there is an instruction to start the re-feeding, that is, the back side copying operation, the re-feeding roller 82, the reversing roller 83 and the separating belt 84 start to rotate, and the sheet beating unit 72 presses the sheet from above. The lowest transfer paper is sequentially fed one by one, and is fed to a position where it merges with the conveyance guide unit 40 through the re-feed guide unit 81, and after the merge, the conveyance roller pair 4
It is guided to the photosensitive drum 31 by the pair 33 and the registration roller pair 44. The transfer paper on which the toner image is transferred on the back surface is discharged to the paper discharge tray 48 via the discharge roller pair 47.

FIG. 3 is a diagram for explaining in detail the structures of a part of the image forming section 3 and the conveyance guide section 40.

That is, the photosensitive drum 31 constituting the image forming section 3 is disposed in the frame 300, and its central axis 31a is rotatably supported by the upright portions of the frame 300 facing each other. In the frame 300, a developing section 33 around the photosensitive drum 31, a toner collecting roller section 34, and a cleaning section 37 are arranged together.

The transfer portion 35 and the separation portion 36, which are arranged so as to face the transfer area of the photosensitive drum 31, are provided on another frame 380 which is arranged below the frame 300 as the transfer unit 350. It is supported. In the frame 380, a pair of rotating rollers 451 and 452 rotatably supported by the opposing upright portions and a conveyor belt 45 stretched around the pair of rotating rollers 451 and 452 are arranged. ing. That is, the pair of rotating rollers 451 and 452 and the conveyor belt 45 are connected to the conveyor unit 4
The transport unit 450 constitutes the frame 38 at the downstream side of the transfer unit 350 in the transport direction of the transfer paper.
It is supported in a fixed state of 0.

Further, on the frame 380, a lower registration roller 44b of a registration roller pair 44 composed of an upper registration roller 44a and a lower registration roller 44b is rotatably axially supported on the upstream side in the transfer unit 350 in the transfer sheet conveying direction. Has been done. That is, the lower registration roller 4
The center axis 44c of the reference numeral 4b is inserted into and supported by the through holes 382 formed in the upright portions of the frame 380 that face each other, and the spring 383 is disposed below the central axis 44c in the through hole 382. So as to elastically contact the upper registration roller 44a.

The frame 300 on which the photosensitive drum 31 and the like are arranged is fixed in the main body 1a of the copying machine, while the frame 380 on which the transfer unit 350 and the transport unit 450 are arranged is made of a transfer paper. The other end side is configured to move up and down by rotating with one end side, which is the downstream side in the transport direction, as a fulcrum.
By moving the other end side of 80 up and down, the transfer unit 350 moves between the position facing the photoconductor drum 31 and the lower position separated from the photoconductor drum 31. In this embodiment, the transport unit 45
The center axis 453 of the rotating roller 452 of 0 is the frame 380.
It becomes the fulcrum of the rotation of.

As shown in FIG. 4, the transfer unit 350 includes a wire supporting portion 351 and a wire supporting portion 351.
And an insulating support portion 352 for insulating and supporting The wire supporting portion 351 is divided into a first chamber 354a and a second chamber 354b by a central partition plate 353, and is formed of a metal plate such as stainless steel whose upper surface is open. Shield case 354
And a charging wire 355 arranged in the first room 354a
And a static elimination wire 356 arranged in the second room 354b.
It is composed of

The charging wire 355 is stretched over the wire supports 355a and 355b at both ends, and the charge eliminating wire 356 is
It is stretched around the wire supports 356a and 356b at both ends. The wire support 355a side of the charging wire 355 and the wire support 356a side of the static elimination wire 356 are connected to terminal plates 357 and 358, respectively. A DC voltage is applied between the terminal plate 357 and the shield case 354, and an AC voltage is applied between the terminal plate 358 and the shield case 354.

Further, the wire supporting portion 351 is fitted with case supporting members 359 and 360 also serving as insulating covers at both ends in the longitudinal direction of the shield case 354. The case supporting member 359 has a pair of projecting portions 359a projecting laterally at lower ends of both ends thereof, and a projection 359b on an upper surface thereof. Further, the case support 360 has a pair of projecting portions 360a projecting laterally at the lower ends of both ends thereof, and a projection 360b on the upper surface thereof.

The insulating support portion 352 is made of an insulating material such as a resin, and has a long insulating case 362 having an upper surface and one side surface in the longitudinal direction opened, and both longitudinal end portions of the insulating case 362. It is composed of elastic members 363 to 366 formed of leaf springs arranged on both sides of the bottom surface.
The insulating case 362 has a plurality of projecting pieces 362a and 362b respectively on the inner surfaces facing each other in the longitudinal direction, and has an elongated guide support portion 362c on one outer surface in the longitudinal direction. The rotation support portions 367, 3 are provided on both outer surfaces of the guide support portion 362c which face each other in the longitudinal direction.
68 is formed to project. In addition, the guide support portion 362
A guide 369 made of a metal plate for guiding the transfer paper to the photosensitive drum 31 is attached to the upper surface of c. In addition, the insulating case 362 is inserted from the inside of the guide support portion 362c.
Two elastic members 370 made of leaf springs protruding inward,
371 is attached to the outer surface of the insulating case 362 while being electrically connected to the guide 369.

That is, in the transfer unit 350, the projecting portions 359a and 360a of the case supporting members 359 and 360 of the wire supporting portion 351 are slid from the open side surface of the insulating case 362 and inserted into the insulating case 362. The projecting portion 359a is elastically sandwiched between the elastic member 363 and the projecting piece 362a and between the elastic member 364 and the projecting piece 362b, and the projecting portion 360a is located between the elastic member 365 and the projecting piece 362a and the elastic member 366. The wire supporting portion 351 and the insulating supporting portion 352 are integrally configured by being elastically sandwiched between the projecting pieces 362b. When the wire support portion 351 and the insulating support portion 352 are integrated, the elastic members 370 and 371 elastically contact the side surface of the shield case 354 of the wire support portion 351, so that the shield case 354 and the guide 369 have the same potential. It has become.

Transfer unit 35 constructed as described above
As shown in FIG. 3, the rotation supporting portions 367 and 368 of the insulating case 362 are rotatably pivotally attached to the upright portions of the frame 380 facing each other on the upstream side in the transporting direction of the transfer paper. That is, recesses 381 for allowing the transfer unit 350 to move downward are formed in the upright portions of the frame 380 that face each other, and the transfer units 350 face each other in which the recesses 381 are formed. The frame 380 is arranged across the upright portion.
Is rotatably supported on the other end side opposite to the one end side in the transporting direction of the transfer paper, which is the fulcrum of the rotation of the.

Transfer unit 350 of frame 380
On the bottom surface of the position corresponding to
84 is attached. Further, a main body frame 390 is disposed at a lower position of the frame 380, and the transfer unit 350 is rotated between the frame 380 and the main body frame 390 by rotating the frame 380 about a central shaft 453 as a fulcrum. The transfer unit 391 for moving between the facing position of the photosensitive drum 31 and the lower position of the photosensitive drum 31, and the transfer unit 350 are connected to the photosensitive drum 31.
And fixing means 392 for fixing at a position facing each other.

As shown in FIG. 5, the moving means 391 has a rotating shaft 393 rotatably supported by opposing support plates (not shown), and extends in the radial direction of the rotating shaft 393. The pair of arms 394, 395 and the pair of arms 394,
It is composed of a roller 396 attached to the tip of 395. Further, the fixing means 392 includes a rotating shaft 393,
A pair of cams 39 extending in the radial direction of the rotating shaft 393.
7, 398. This pair of cams 39
7, 398 are arranged outside the pair of arms 394, 395, extend in the same direction as the pair of arms 394, 395, and have an elongated shape longer than the pair of arms 394, 395. Is formed in. That is,
The pair of cams 397 and 398 has a shape in which a portion from the rotating shaft 393 to the tip portion has a rising slope,
It becomes arcuate as it approaches the tip, and becomes flat at the end, which is the peripheral surface portion farthest from the rotating shaft 393.

As shown in FIG. 3, the roller 396 contacts the elastic member 384 on the bottom surface of the frame 380 to fix the frame 380 at the upper position and the pair of cams 39.
7, 398, the flat portion of the tip thereof abuts the bottom surface of the transfer unit 350 to fix the transfer unit 350 to the position facing the photoconductor drum 31. When the transfer unit 350 is at a position facing the photoconductor drum 31, the protrusion 35 on the upper surface of the transfer unit 350 is prevented so that the transfer unit 350 does not directly contact the surface of the photoconductor drum 31.
9b and 360b come into contact with the lower end surfaces of the upright portions of the frame 300 supporting the photoconductor drum 31 that face each other. Further, when the transfer unit 350 is at a position facing the photoconductor drum 31, the lower registration roller 44b supported by the frame 380 elastically contacts the upper registration roller 44a.

6 to 9, the roller 396 and the cams 397 and 398 are moved by the rotation of the rotation shaft 393, and the frame 380 and the transfer unit 35 are correspondingly moved.
It is a figure for explaining the state where 0 moves.

That is, when a jam occurs around the photosensitive drum 31, the knob (not shown) attached to the end of the rotary shaft 393 is operated to rotate the rotary shaft 393 counterclockwise. FIG. 6 shows a state in which the rotating shaft 393 is started to rotate, and the roller 396 slightly moves counterclockwise along the circumference around the rotating shaft 393.
The frame 380 exists at substantially the same position. Further, the cams 397 and 398 slightly move from the flat portion to the arc portion, but the transfer unit 350 is present at substantially the same position.

Further, when the rotary shaft 393 is rotated counterclockwise, the rollers 396 move along the circumference as shown in FIG. 7, and the height from the rotary shaft 393 decreases. As a result, the frame 380 is attached to the central shaft 4 on the one end side by its own weight.
By rotating around 53 as a fulcrum, the other end side is lowered. The contact portions of the cams 397 and 398 with the transfer unit 350 move from the flat portion to the arc portion, and the rotation shaft 39
The height from 3 becomes lower. As a result, the transfer unit 3
50 is rotated by its own weight using the rotation support portions 367 and 368 on the other end side in the opposite direction to the fulcrum of the frame 380 as fulcrums, so that the one end on the same side as the fulcrum of the frame 380 descends.

Further, when the rotating shaft 393 is rotated counterclockwise, the height of the roller 396 is further lowered as shown in FIG. 8, so that the frame 380 has the other end in the opposite direction to the rotating fulcrum. The side end is lowered to a position where it abuts on the main body frame 390. Also in the transfer unit 350, the positions of the contact portions of the cams 397 and 398 with the transfer unit 350 are further lowered, so that the one end side in the direction opposite to the rotation fulcrum is further lowered.

Further, when the rotary shaft 393 is rotated counterclockwise, the height of the roller 396 is further lowered as shown in FIG. 9, but the frame 380 has the other end of the main body frame 390. Since the roller 396 is in contact with and cannot descend, the roller 396 is attached to the elastic member 384 on the bottom surface of the frame 380.
Will be separated from The transfer unit 350 is the cam 3
By further lowering the position of the contact portion of 97, 398 with the transfer unit 350, the one end side is further lowered, and both longitudinal ends thereof are substantially in contact with the bottom of the recess 381. At this time, the upper surface of the transfer unit 350 is lower than the transfer sheet transport surface of the transport unit 450.

In this way, when the other end side of the frame 380 in the direction opposite to the rotation fulcrum is lowered, the transfer unit 35
Since one end side in the direction opposite to the rotation fulcrum of 0 descends, the distance between the photoconductor drum 31 and the transfer unit 350 becomes wider than that when the transfer unit 350 is fixed to the frame 380. As a result, it becomes possible to easily pull out the transfer paper, which causes the jam, to the outside. That is, in the conventional structure, since the transfer unit 350 is fixed to the frame 380, even if the frame 380 is lowered, the upper surface of the transfer unit 350 is always located at substantially the same position as the transfer sheet transport surface of the transport unit 450. Although it is not possible to widen the distance between the photoconductor drum 31 and the photoconductor drum 31, the photoconductor drum 31 is lowered because the transfer unit 350 descends as described above in the present embodiment.
The distance between and can be widened.

After the transfer sheet causing the jam is removed, the transfer unit 350 at the lower position separated from the photoconductor drum 31 is moved to the position facing the photoconductor drum 31 by the operation reverse to the above. That is, the rotary shaft 393 in the state of FIG. 9 is rotated clockwise by operating a knob (not shown). Then, as shown in FIG. 8, the roller 396 contacts the elastic member 384 on the bottom surface of the frame 380, and
The cams 397 and 398 contact the bottom surface of the transfer unit 350 to rotate the transfer unit 350 with the rotation support portions 367 and 368 as fulcrums, so that one end side of the transfer unit 350 opposite to the rotation support portions 367 and 368 is moved. Lift slightly.

Further, when the rotating shaft 393 is rotated clockwise, the roller 396 is moved to the frame 38 as shown in FIG.
By rotating 0 about the rotation fulcrum, the other end side in the direction opposite to the rotation fulcrum is lifted upward. One ends of the transfer unit 350 are further lifted up by the cams 397 and 398, and the upper surface of the transfer unit 350 is substantially level with the carrying surface of the carrying unit 450.

Further, when the rotating shaft 393 is rotated clockwise, the roller 396 is moved to the frame 38 as shown in FIG.
0 to the highest position and the cam 39
7, 398 will lift the transfer unit 350 to the uppermost position. As a result, the transfer unit 3
50 moves to the position facing the photosensitive drum 31.

At this time, the elastic member 384 on the bottom surface of the frame 380 is slightly bent to absorb the excessive pressing force of the roller 396, and the elastic members 363 to 366 in the transfer unit 350 are bent to bend the cam 397. The transfer unit 350 does not come into contact with the frame 300 on which the photosensitive drum 31 is arranged with an excessive pressing force by absorbing an excessive pressing force of the 398.

Further, when the rotary shaft 393 is rotated clockwise, as shown in FIG. 3, the flat portion, which is the peripheral surface portion of the cams 397 and 398 farthest from the rotary shaft 393, is the bottom surface of the transfer unit 350. And the transfer unit 350 is fixed at that position so as not to move carelessly. As a result, the careless movement of the frame 380 is prevented.

In this embodiment, the frame 3
The rotation fulcrum of 80 is formed on the one end side which is the downstream side in the transfer sheet conveyance direction, and the rotation fulcrum of the transfer unit 350 is the other end side opposite to the one end side which is the transfer sheet upstream side in the conveyance direction. However, the rotation fulcrum of the frame 380 is formed on the one end side which is the upstream side in the transfer paper transport direction, and the rotation fulcrum of the transfer unit 350 is the one end which is the downstream side in the transfer paper transport direction. It may be formed on the other end side opposite to the side. In short, the rotation fulcrum of the frame 380 and the rotation fulcrum of the transfer unit 350 may be on opposite sides of the transfer unit 350.

Further, in this embodiment, the transport unit 450 is fixed to the frame 380, but when the frame 380 is lowered, the transport unit 450 is also lowered so that the transport surface of the transport unit 450 is, for example, as shown in FIG. Alternatively, the upper surface of the transfer unit 350 at the position 9 may be located at substantially the same position. In such a case, the jam clearance work can be performed more easily.

[0057]

As described above, according to the present invention, the frame is rotatably arranged with one end side in the transporting direction of the transfer paper as a fulcrum, and the transfer unit is fulcrum at the other end side opposite to the frame. As it is rotatably supported by the frame,
When the other end of the frame moves downward with one end as a fulcrum, one end of the transfer unit moves downward with the other end as a fulcrum, and the gap between the transfer unit and the photosensitive drum widens. As a result, it becomes possible to easily perform the jam processing as compared with the case where only the frame is moved.

According to the second aspect of the present invention, when the transfer unit is moved to the lower position separated from the photosensitive drum, the upper surface of the transfer unit is located at a position lower than the transfer surface of the transfer sheet of the transfer unit. Since it is moved up to, it becomes possible to easily perform jam processing.

Further, according to the invention of claim 3, since the moving means is constituted by including the roller, when the transfer unit is moved from the lower position of the photosensitive drum to the facing position of the photosensitive drum, the rotation unit is rotated. The frame can be lifted by rotating the moving shaft and moving the roller, which is in contact with the bottom surface of the frame, in the upper direction along the circumference around the rotating shaft. When the transfer unit is moved from the position facing the photoconductor drum to the position below the photoconductor drum, the rotation shaft is rotated in the direction opposite to the above direction so that the roller abutting on the bottom surface of the frame is moved to the above circumference. The frame can be lowered by its own weight by moving it along the lower direction.

Further, according to the invention of claim 4, since the fixing means comprises the cam, the cam is also rotated at the same time when the rotation shaft is rotated and the roller lifts the frame. When the transfer unit is moved to the position facing the photoconductor drum, the peripheral surface of the cam contacts the bottom surface of the transfer unit to fix the transfer unit to the position facing the photoconductor drum.

Further, according to the invention of claim 5, since the elastic member is provided at the position where the roller of the frame abuts,
It is possible to prevent the transfer unit from being pressed against the photosensitive drum side with an excessively large force.

Further, according to the invention of claim 6, since the transfer unit is provided with the elastic member between the wire supporting portion and the insulating holding portion, the transfer unit is applied to the photosensitive drum side with an unnecessarily large force. It is possible not to press.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing an embodiment of a copying machine that is an image forming apparatus of the present invention.

FIG. 2 is an internal configuration diagram of the copying machine shown in FIG.

3 is a diagram showing in detail the configuration of part of an image forming unit and a conveyance guide unit of the copying machine shown in FIG.

FIG. 4 is a diagram showing a configuration of a transfer unit of the copying machine shown in FIG.

5 is a diagram showing a configuration of moving means and fixing means of the copying machine shown in FIG.

FIG. 6 is a diagram for explaining a moving state of a frame and a transfer unit of the copying machine shown in FIG.

FIG. 7 is a diagram for explaining a moving state of a frame and a transfer unit of the copying machine shown in FIG.

FIG. 8 is a diagram for explaining a moving state of a frame and a transfer unit of the copying machine shown in FIG.

FIG. 9 is a diagram for explaining a moving state of a frame and a transfer unit of the copying machine shown in FIG.

[Explanation of symbols]

 1 Copier 2 Optical Mechanism 3 Image Forming Section 4 Paper Conveying Mechanism 5 Reversing Mechanism 6 Double-sided Unit Section 31 Photosensitive Drum 350 Transfer Unit 351 Wire Supporting Section 352 Insulation Holding Section 363, 364, 365, 366 Elastic Member 380 Frame 384 Elastic Member 391 Moving means 392 Fixing means 393 Rotating shaft 394, 395 Arm 396 Roller 397, 398 Cam 450 Conveying unit

Claims (6)

[Claims] 1. A transfer unit for transferring an original image onto a transfer paper in a transfer area of a photoconductor drum, a transport unit for transporting the transfer paper on which the original image is transferred to a fixing unit, and the transfer unit and the transport unit are supported. In addition, a frame disposed so as to be rotatable around one end side of the transfer paper in the conveying direction as a fulcrum, and the transfer unit facing the photosensitive drum by rotating the frame around the fulcrum as a center. Moving means for moving between a position and a lower position separated from the photosensitive drum, and fixing means for fixing the transfer unit to the facing position when the transfer unit is moved to the facing position of the photosensitive drum. The image forming apparatus, wherein the transfer unit is rotatably supported by the frame with the other end side opposite to the one end side as a fulcrum. . 2. The transport unit is fixed to and supported by a frame, and when the transfer unit is moved to a lower position separated from the photoconductor drum, the upper surface of the transfer unit is the transport unit. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is rotatable to a position lower than a conveyance surface of the transfer sheet. 3. The moving means is attached to a rotary shaft, an arm extending in a radial direction from the rotary shaft, a tip of the arm, and abuttable to a bottom surface of the frame. The image forming apparatus according to claim 1, wherein the image forming apparatus comprises a roller. 4. The fixing means comprises the rotary shaft and a cam extending from the rotary shaft in the radial direction and capable of contacting the bottom surface of the transfer unit. The image forming apparatus according to claim 3, wherein 5. The image forming apparatus according to claim 3, wherein the frame includes an elastic member at a position where the roller abuts. 6. The transfer unit includes a wire support part,
An insulating holding part supported by the frame and insulatingly holding the wire supporting part, and an elastic member interposed between the wire supporting part and the insulating holding part. Item 6. The image forming apparatus according to any one of Items 1 to 5.