JP2010256741A - Drum unit and image forming apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drum unit capable of achieving reduction of manufacture cost and space saving; and to provide an image forming apparatus mounted with the drum unit. <P>SOLUTION: The drum unit includes a photoreceptor drum (18) which is driven to form a toner image on an image forming surface (76), a cleaning member (52) which scrapes residual toner from the image forming surface, and a toner collection part (80) which collects the scraped residual toner from a casing (81) to a collecting container (84). The toner collection part includes a screw (86) conveying the residual toner in the casing to the collecting container, a bush (90) installed in the casing and supporting one end side (87) of the screw so as to be freely rotatable, and a collecting shutter (92) configured to open/close a toner conveyance path (82) between the casing and the collecting container and having a bearing part (96) supporting the other end side (88) of the screw so as to be freely rotatable. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drum unit that outputs a toner image to a medium and an image forming apparatus equipped with the drum unit.

  In this type of image forming apparatus, an electrophotographic system is used. When the charger precharges the photosensitive drum and the exposure device irradiates the image forming surface of the drum with light, an electrostatic latent image is formed on the image forming surface. An image is formed. The developing device carries toner, and the toner adheres to the electrostatic latent image to form a toner image. The toner image is transferred and fixed on the paper.

Here, in order to transfer the next toner image to the sheet by the image forming apparatus, it is necessary to clean the image forming surface after the previous transfer and to remove the remaining toner from the image forming surface.
Specifically, a cleaning blade is provided on the downstream side of the transfer position with the medium as viewed in the rotation direction of the photosensitive drum, and when the blade comes into contact with the image forming surface, residual toner is formed in the image. It can be removed from the surface. The removed toner is collected in a collection container (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-303311

  However, the above-described conventional technique has a problem that it is difficult to reduce the manufacturing cost. In the above technique, the screw conveys the residual toner, but both ends of the screw are rotatably supported by the bearing portion of the casing, and a bearing portion is separately required in addition to the recovery shutter. This is because the score increases.

Moreover, since the edge part of the screw of the said technique protrudes from the casing, there also exists a concern that an apparatus will become large sized.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a drum unit that can solve the above-described problems and can achieve a reduction in manufacturing cost and space saving, and an image forming apparatus equipped with the drum unit.

  According to a first aspect of the invention for achieving the above object, there is provided a photosensitive drum that forms a toner image on an image forming surface by driving, a cleaning member that scrapes off residual toner from the image forming surface, and a scraped residual toner. A toner collecting section for collecting the toner from the casing into the collecting container, the toner collecting section being installed in the casing and transporting residual toner in the casing toward the collecting container, and freely rotating one end of the screw. And a recovery shutter having a bearing portion that rotatably supports the other end side of the screw. The bush is supported by the bush, and the toner conveyance path between the casing and the recovery container is openable and closable.

According to the first invention, the drum unit includes a photosensitive drum, a cleaning member, and a toner recovery unit. The cleaning member scrapes off residual toner from the image forming surface of the photosensitive drum, and the toner recovery unit includes: The residual toner thus scraped off is collected from the casing into a collection container.
Here, the toner collecting unit conveys residual toner using a screw, and one end side of the screw is rotatably supported by a bush.

On the other hand, the other end side of the screw is rotatably supported by a bearing portion of the recovery shutter, and both ends of the screw are rotatably supported. Therefore, the outer diameter portion of the screw does not contact the inner wall of the casing, and the rotation of the screw is stabilized.
In addition, the collection shutter also serves as a screw bearing function in addition to the toner conveyance path opening and closing function. Cost reduction can be achieved.

The second invention is the configuration of the first invention,
The recovery shutter has an inner wall surface that closes the end surface of the casing, and a bearing portion is formed to protrude only from the inner wall surface toward the inside of the casing.
According to the second invention, in addition to the action of the first invention, the bearing portion protrudes from the inner wall surface of the recovery shutter toward the inside of the casing. No protrusions are formed. Therefore, the space saving of the unit is surely achieved.

The third invention is an image forming apparatus equipped with the drum unit of the first or second invention.
According to the third invention, in addition to the effects of the first and second inventions, if the above-described drum unit is mounted, the manufacturing cost can be reduced and the space can be saved. Contributes to cost reduction and miniaturization.

  According to the present invention, since the recovery shutter also serves as a screw bearing function, it is possible to provide a drum unit that can achieve a reduction in manufacturing cost and space saving, and an image forming apparatus equipped with the drum unit.

1 is a schematic configuration diagram of a printer according to an embodiment. It is an external appearance perspective view of the drum unit of FIG. It is arrow sectional drawing seen from the III-III line of FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. It is an external appearance perspective view of the screw of FIG. It is an external appearance perspective view of the collection | recovery shutter of FIG. FIG. 2 is an explanatory diagram of a waste toner flow by the drum unit of FIG. 1.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
FIG. 1 schematically shows the structure of a printer 1 capable of color printing, which is an example of an image forming apparatus. The cross section shown in the figure is seen from the left side of the printer 1. For this reason, the front surface of the printer 1 is positioned on the right side and the rear surface of the printer 1 is positioned on the left side.

As shown in the figure, a paper discharge tray 36 is provided above the apparatus main body 2 of the printer 1, and a plurality of operation keys used for various operations of the user and various types are provided near the tray 36. A front cover 5 on which a screen for displaying information is arranged is provided.
Further, a sheet feeding cassette 4 is disposed below the apparatus main body 2, and sheets of sheets are stored in the storage unit 40 in a stacked state. A roller 46 is provided on the upper right side of the accommodating portion 40 as viewed in FIG.

Then, the paper is sent toward the upper right of the cassette 4 in the figure, and the sent paper is conveyed upward along the front surface of the printer 1 inside the apparatus main body 2.
Further, the cassette 4 is configured so that it can be pulled out to the front side of the printer 1, that is, in the right direction in FIG. 1. Can be replaced with another type of paper.

Inside the apparatus main body 2, a conveyance roller 10, a registration roller 14, an image forming unit 16, and a transfer unit 30 are sequentially arranged on the downstream side when viewed in the sheet conveyance direction from the cassette 4.
Four drum units 17 are arranged side by side in the image forming unit 16, and each unit 17 is provided with a photosensitive drum 18 (FIG. 2). The drum 18 is rotatably installed and is driven clockwise in FIG. 1 by a drive motor (not shown). The drum 18 of the present embodiment is an a-Si drum having an amorphous silicon-based layer on the surface thereof.

  Further, an exposure device 15 is provided between the drum 18 and the cassette 4, and laser light is irradiated from the exposure device 15 toward each drum 18 (FIG. 1). 1 and 3, a charger 20, a developing device 24, an intermediate transfer roller 13, and a cleaning unit 50 are provided at appropriate positions around each drum 18, respectively. In FIG. 3, the intermediate transfer belt 12, the developing device 24, and the like are not shown.

The charger 20 has a charging roller 21 in contact with the drum 18 and a rubbing roller 22 for rubbing and rubbing the surface of the roller 21, and is located under the housing 47 of the unit 17 shown in FIG. The 18 image forming surfaces 76 are uniformly charged.
1 and 3, the developing device 24 is disposed on the left side of the unit 17 and has a developing roller facing the drum 18. The developing roller is driven counterclockwise in the figure by a drive motor (not shown).

  Returning again to FIG. 1, the intermediate transfer belt 12 is disposed above each drum 18, and four toner containers 23 are disposed between the transfer belt 12 and the tray 36. These containers 23 are arranged in the order of yellow, magenta, cyan, and black from the back side to the front side of the printer 1, and the capacity of the black container is the largest. Yes.

The transfer unit 30 includes a transfer roller 31, and the roller 31 is configured to be able to press against the intermediate transfer belt 12 from obliquely below.
The belt 12 and the roller 31 use toner supplied from each of the four toner containers 23 to form a nip portion for transferring a toner image onto a sheet.

Further, a fixing unit 32, a discharge branching unit 34, and a tray 36 are sequentially arranged on the downstream side of the transfer unit 30 when viewed in the paper transport direction.
In this embodiment, a duplex printing unit 38 is formed between the transfer unit 30 and the manual feed tray 3. The unit 38 branches from the discharge branching portion 34 on the front side of the apparatus main body 2 and extends downward, and is connected to the upstream side of the registration roller 14.

Here, as shown in FIG. 3, the cleaning unit 50 of the present embodiment, as viewed in the rotation direction of the drum 18, is downstream of the transfer position with the intermediate transfer roller 13. ) 52, a rubbing roller 56, a cleaning blade 58 for both ends, and a toner collecting unit 80.
The rubbing roller 56 is driven counterclockwise in the figure by a drive motor (not shown), and rubs and polishes the image forming surface 76 after the toner image is transferred in the trail direction.

As a result, the rubbing roller 56 removes residual toner and the like adhering to the amorphous silicon-based layer of the image forming surface 76.
The image area cleaning blade 52 includes a galvanized steel body fixed to the housing 47 and a polyurethane rubber blade portion thermally welded to the body 47. The blade portion is arranged along the rotation axis of the drum 18 (FIG. 3), and the blade portion contacts in the counter direction to scrape residual toner and the like adhering to the image forming surface 76.

  As shown in FIG. 2, the image forming surface 76 corresponds to the center portion of the drum 18, and the non-image forming surfaces 78 and 78 exist on the entire outer periphery of the drum 18. . In this embodiment, the gap between the developing roller and the drum 18 described above is set by contact between a gap regulating roller that rotates around the drum 18 and the non-image forming surface 78.

That is, the non-image forming surfaces 78 and 78 are portions that are in contact with the restriction roller, and it is necessary to devise a technique for preventing toner from adhering to the portions.
Therefore, in this embodiment, the cleaning blades 58 for both ends are provided on the housing 47, and the toner adhering to the non-image forming surfaces 78 and 78 is disposed so as to be scraped off in the counter direction.

On the other hand, the residual toner scraped off from the image forming surface 76 by the image area cleaning blade 52 and the rubbing roller 56 is collected from the toner collecting section 80 into the collecting container 84 of FIG.
More specifically, the toner collecting unit 80 has a casing 81 positioned on the right side of the drum 18 as viewed in FIG. 3, and in addition to the image area cleaning blade 52 and the rubbing roller 56, a screw is provided inside the casing 81. 86 is arranged.

The screw 86 is disposed on the right side of the image area cleaning blade 52 and below the rubbing roller 56 as viewed in the same figure, and extends along the rotational axis direction of the drum 18.
Specifically, the screw 86 has a spiral blade portion 89 on the peripheral wall of the shaft extending along the rotation axis direction of the drum 18 (FIGS. 4 and 5).

  4 and 5, a drive end (one end side) 87 is provided at the left end of the shaft, and the tip is connected to a drive motor (not shown). Further, the drive end portion 87 is rotatably supported by a cylindrical bush 90 installed on the left inner side of the casing 81 as viewed in FIG. 2, in other words, on the left side of the casing 81 as viewed in FIG. .

On the other hand, on the opposite side of the drive end portion 87, that is, on the right end of the shaft viewed in FIG. 5, a driven end portion (other end side) 88 having a smaller diameter than the shaft protrudes in the rotation axis direction of the screw 86. In addition to the left end of the shaft, the right end of the shaft is also rotatably supported.
Specifically, a cup-shaped collection shutter 92 is disposed on the right side of the casing 81 as viewed in FIG.

The shutter 92 is arranged so that the circular opening faces the inside of the casing 81, and as shown in FIG. 6A, the periphery of the opening is continuous with the peripheral wall 93, and the peripheral edge of the peripheral wall 93 is circular. The outer wall surface 95 is connected to the outer wall surface 95, and the outer wall surface 95 forms a bottomed portion of the shutter 92.
In addition, a connecting piece 97 protrudes in a radial direction at an appropriate position of the peripheral wall 93. In the peripheral wall 93, a toner opening 98 is formed through the peripheral wall 93 on the opposite side of the connecting piece 97 (FIG. 5B), and the residual toner in the casing 81 is sent downward ( FIG. 4).

Further, a groove 99 that engages with the protrusion of the casing 81 is formed in the vicinity of the toner opening 98 (FIG. 6B) to prevent the shutter 92 from falling off the casing 81.
The shutter 92 is configured to be rotatable around the rotation axis of the screw 86 in accordance with the urging force of the spring 100 in FIGS. 2 and 4, and when the drum unit 17 is lifted upward from the apparatus main body 2. The connecting piece 97 is rotated by the biasing force of the spring 100. As a result, the toner opening 98 also rotates and deviates from the lower position, so that the inside of the casing 81 is sealed.

On the other hand, when the drum unit 17 is lowered and attached to the apparatus main body 2, the connecting piece 97 comes into contact with the joint portion of the casing 81 and faces the opposite side against the biasing force of the spring 100. Rotate. Therefore, the toner opening 98 returns to the lower position, and the inside of the casing 81 is opened.
The recovery shutter 92 of this embodiment also has a function of supporting the screw 86 in a rotatable manner.

More specifically, as shown in FIG. 6, an inner wall surface 94 that closes the inside of the casing 81 is provided on the back side of the flush outer wall surface 95, and a bearing portion 96 is formed on the inner wall surface 94. ing. That is, the bearing portion 96 protrudes only from the inner wall surface 94 toward the inside of the casing 81, and supports the driven end portion 88 rotatably.
When the drive motor is driven in a state where the unit 17 is mounted on the apparatus main body 2, both ends of the screw 86 are rotatably supported, the blade portion 89 rotates, and toner around the blade portion 89 has toner opening 98. Gathered towards.

  Subsequently, the toner traveling from the toner opening 98 toward the toner conveyance path 82 proceeds as indicated by a downward arrow in FIG. Next, another screw (not shown) extending in a direction substantially orthogonal to the rotation axis of the screw 86 is provided below the toner conveyance path 82, and the toner in the toner conveyance path 82 The screw 1 is conveyed toward the direction connecting the front side and the back side of the printer 1 and collected in the collection container 84.

  When the printer 1 equipped with the drum unit 17 performs printing, the paper is separated from the cassette 4 by the roller 46 and sent out one by one. The sent paper reaches the registration roller 14. The roller 14 feeds the paper to the transfer unit 30 at a predetermined paper feed timing while correcting the oblique feeding of the paper and measuring the image transfer timing with the toner image formed by the image forming unit 16.

On the other hand, for each photosensitive drum 18, first, the charger 20 charges the image forming surface 76 of the drum 18. Next, when the exposure device 15 irradiates the image forming surfaces 76 with laser beams, electrostatic latent images are formed on the image forming surfaces 76, and toner images of respective colors are formed from the electrostatic latent images.
Each toner image is transferred onto a sheet by the transfer unit 30. The toner scattered on the non-image forming surface 78 and the toner remaining on the image forming surface 76 at the time of forming a toner image are removed by the cleaning unit 50.

  Thereafter, the sheet is fed toward the fixing unit 32 with an unfixed toner image carried thereon, and is heated and pressurized by the fixing unit 32 to fix the toner image. Next, the sheet sent from the fixing unit 32 is discharged to the discharge tray 36 via the discharge roller 35 and stacked in the height direction.

  When double-sided printing is performed on this single-sided printing, the conveyance direction of the paper discharged from the fixing unit 32 is switched by the discharge branching unit 34. That is, the sheet printed on one side is pulled back into the apparatus main body 2 and conveyed to the duplex printing unit 38. Subsequently, the sheet is sent toward the upstream side of the registration roller 14 and is sent again toward the transfer unit 30. As a result, the toner image is transferred to the side of the paper that has not been printed.

  As described above, according to the present exemplary embodiment, the drum unit 17 includes the photosensitive drum 18, the image area cleaning blade 52, and the toner recovery unit 80, and the cleaning blade 52 is an image forming surface of the drum 18. The residual toner is scraped off from 76, and the toner recovery unit 80 recovers the residual toner thus scraped off from the casing 81 to the recovery container 84.

  Here, the toner collecting unit 80 conveys residual toner using a screw 86, and the driving end 87 of the screw 86 is rotatably supported by the bush 90, whereas the driven end of the screw 86 is driven. 88 is rotatably supported by the bearing portion 96 of the recovery shutter 92, and both ends of the screw 86 are rotatably supported. Therefore, the blade portion 89 does not contact the inner wall of the casing 81, and the rotation of the screw 86 is stabilized.

Further, since the collection shutter 92 also has a function of opening and closing the toner conveyance path 82 and a bearing function of the screw 86, an increase in the number of parts of the unit 17 can be suppressed as compared with the case where a bearing is provided separately from the shutter. The manufacturing cost can be reduced.
Further, since the bearing portion 96 protrudes from the inner wall surface 94 of the recovery shutter 92 toward the inside of the casing 81, no protrusion is formed on the back side of the inner wall surface 94, that is, the outer wall surface 95. Therefore, space saving of the unit 17 is achieved reliably.

Furthermore, if the drum unit 17 described above is installed, the manufacturing cost can be reduced and the space can be saved, which contributes to the reduction in the manufacturing cost and size reduction of the printer 1.
The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims.

For example, in the above embodiment, the toner image is transferred to the intermediate transfer belt at the transfer position, but this toner image may be transferred to the paper at the transfer position.
In this embodiment, an example in which the image forming apparatus is embodied in a printer is shown. However, the image forming apparatus of the present invention can naturally be applied to a multifunction machine, a copying machine, a facsimile machine, and the like.

  In any of these cases, similar to the above, the manufacturing cost can be reduced and the space can be saved.

1 Printer (image forming device)
17 Drum Unit 18 Photosensitive Drum 47 Housing 50 Cleaning Unit 52 Image Area Cleaning Blade (Cleaning Member)
76 Image forming surface 80 Toner collection unit 81 Casing 82 Toner transport path 84 Collection container 86 Screw 87 Drive end (one end side)
88 Driven end (other end side)
90 Bush 92 Recovery Shutter 94 Inner Wall 96 Bearing

Claims (3)

A photosensitive drum that forms a toner image on the image forming surface by driving;
A cleaning member that scrapes off residual toner from the image forming surface;
A toner collecting section for collecting the scraped residual toner from the casing into a collecting container;
The toner recovery unit
A screw for conveying residual toner in the casing toward the collection container;
A bush installed in the casing and rotatably supporting one end of the screw;
A drum unit configured to be capable of opening and closing a toner conveyance path between the casing and the recovery container, and including a recovery shutter having a bearing portion that rotatably supports the other end side of the screw. . The drum unit according to claim 1,
The drum unit, wherein the recovery shutter has an inner wall surface that closes an end surface of the casing, and the bearing portion projects from the inner wall surface only toward the inside of the casing.   An image forming apparatus comprising the drum unit according to claim 1.

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