JP2006078675A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a leak of recovered toner in a developing device that develops an electrostatic latent image, formed on a latent image carrier, with developer containing toner. <P>SOLUTION: Toner scraped from a seal roll 123 as a result of flying and sticking to the surface of the seal roll 123 is guided into the developing device by elastic members 125 disposed at both plate-shaped ends of a long plate-shaped scraper 124. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device that develops an electrostatic latent image formed on a latent image carrier using a developer containing toner.

  In an image forming apparatus used for an electrophotographic copying machine, a printer, or a facsimile, a latent image carrier represented by a photosensitive drum is charged, and an electrostatic latent image is formed on the surface of the latent image carrier by image exposure. The toner image is formed by developing with a developer containing toner using a developing device provided with a developing roll arranged to be close to or in contact with the latent image carrier in a predetermined developing region. Then, the formed toner image is directly transferred or fixed, for example, via an intermediate transfer member on the recording medium to form an image on the recording medium.

  Conventionally, the developing device itself and the inside of the image forming apparatus are contaminated by floating toner (hereinafter, this floating toner is referred to as cloud toner) generated mainly in the vicinity of the development area, or the cloud toner adheres to the recording medium. There is a problem that the image quality of the formed image is deteriorated.

As a developing device having a function to cope with such a problem, a cloud toner is provided on the downstream side in the rotation direction of the latent image carrier from the developing region so as to be spaced apart from the outer peripheral surface of the latent image carrier. A seal member in the form of a roll (hereinafter, this seal member is referred to as a seal roll) and a long plate-shaped edge There has been proposed a developing device that collects the scraped toner in the housing of the developing device by providing a scraper that contacts the surface of the roll and scrapes off the cloud toner adsorbed on the surface (for example, (See Patent Document 1).
Japanese Patent Laid-Open No. 200-112237

  According to the developing device proposed in Patent Document 1 described above, the toner scraped off by the scraper is collected inside the developing device by the rising of the developer on the developing roll, and in the vicinity of the developing region where cloud toner is generated. Since the space is substantially sealed by the seal roll, the collected toner is prevented from leaking out of the developing device. However, since the seal roll is generally longer than the developing roll in order to reliably adsorb cloud toner, the toner scraped off by the scraper at both ends of the long plate shape of the seal roll Depending on the top of the developer, it is difficult to collect inside the developing device, and the toner scraped off by the scraper at both ends of the developer stays in the vicinity of the scraped-off, and the gap between the housing of the developing device and the scraper The toner may gradually leak out of the developing device. In addition, in an image forming apparatus that can draw out a marking unit having a plurality of developing devices and a plurality of latent image carriers attached thereto in the axial direction of the developing device, the marking unit is pulled out. As a result of the operation of pushing or pushing in, the toner staying as described above may leak out of the developing device from the gap between the housing of the developing device and the scraper.

  In view of the above circumstances, an object of the present invention is to provide a developing device in which leakage of collected toner is prevented.

The developing device of the present invention that achieves the above object provides:
A developer containing toner, which is disposed so as to be close to or in contact with a latent image carrier that carries an electrostatic latent image and rotates in a predetermined direction in a predetermined development area, is supported on the development area. A developer carrying member for developing the electrostatic latent image with toner by supplying the developer;
Rotating in the predetermined direction, adsorbing the floating toner, which is arranged downstream of the developing area in the rotation direction of the latent image carrier and spaced from the outer peripheral surface of the latent image carrier by a predetermined distance. An adsorption roll;
A scraper that has a long plate shape, a long edge of the plate shape abuts on the surface of the suction roll, and scrapes the floating toner adsorbed on the surface;
The scraper is provided with an elastic member provided at each of both end portions of the plate shape on the opposite side of the suction roll.

  In the developing device of the present invention, the toner scraped off from the suction roll that has adsorbed the floating toner on the surface of the scraper having a long plate shape is disposed at each of the both ends of the plate shape. Since the elastic member guides the inside of the developing device, the toner collected by scraping is prevented from leaking out of the developing device.

  Here, in the developing device of the present invention, it is preferable that the elastic member has an end facing the upstream side in the rotation direction of the suction roll inclined toward the center side of the scraper.

  According to such a preferable embodiment, the toner is reliably guided to the inside of the developing device by the inclined end of the elastic member.

  In the developing device of the present invention, the elastic member is configured such that an end of the suction roll facing the upstream side in the rotation direction is inclined toward the center side of the scraper and intersects with a short side of the scraper. More preferably it is.

  According to such a more preferable embodiment, the inclined end of the elastic member intersects the short side of the scraper, whereby the toner is more reliably guided to the inside of the developing device.

  Further, in the developing device of the present invention, the developer may be a two-component developer composed of a magnetic carrier and a toner.

  Generally, the toner contained in the two-component developer is finer than the toner contained in the one-component developer, so the floating toner is likely to be generated, and the toner collected by scraping is collected outside the developing device. Although it is easy to leak, if the developing device is applied with a two-component developer, it is possible to prevent the collected toner from leaking.

  According to the present invention, a developing device in which leakage of collected toner is prevented is provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  Here, an embodiment in which the present invention is applied to a developing device that develops an electrostatic latent image formed on a latent image carrier using a two-component developer composed of a magnetic carrier and toner will be described.

  FIG. 1 is a schematic configuration diagram of an image forming apparatus incorporating a developing device corresponding to an embodiment of the present invention.

  As shown in FIG. 1, an image forming apparatus 1 according to this embodiment is an image forming apparatus that employs a full-color tandem method, and includes yellow (Y), magenta (M), cyan (C), and black (B). The four toner image forming units corresponding to each of the four color toners are used to form toner images of the respective colors in synchronism with the feeding of the intermediate transfer belt, and the toner images are formed in the middle. The image is superimposed on the intermediate transfer belt as a medium (primary transfer), and the color toner image superimposed on the intermediate transfer belt is transferred (secondary transfer) to a sheet as a recording medium and fixed.

  The image forming apparatus 1 shown in FIG. 1 includes four toner image forming units 10 and four primary transfer rolls 20. In addition, the image forming apparatus 1 includes a semiconductive intermediate transfer belt 30 that is supported by four support rolls 31 and circulates counterclockwise, a batch transfer apparatus 40 that performs secondary transfer, and unfixed toner. A fixing device 50 for fixing the image on the sheet is also provided.

  The four toner image forming units 10 are arranged side by side in the circulation direction of the intermediate transfer belt 30, and each toner image forming unit 10 is provided with a photosensitive drum 11 that rotates in a clockwise direction. The surface of each photosensitive drum 11 is in contact with the intermediate transfer belt 30. The primary transfer roll 20 is disposed at a position facing the photosensitive drum 11 with the intermediate transfer belt 30 interposed therebetween, and a portion where the photosensitive drum 11 and the intermediate transfer belt 30 are in contact is a primary transfer position.

  Each toner image forming unit 10 also includes a developing device 12, a contact charging device 13, and a cleaning device 14. The developing device 12 corresponds to an example of the developing device according to the present invention, and is disposed around the photosensitive drum 11 and upstream of the primary transfer position. Each developing device 12 is provided with a toner cartridge 15 that supplies toner via a reserve tank 16. The contact charging device 13 is disposed further upstream than the developing device 12. Further, the cleaning device 14 is disposed around the photosensitive drum 11 and downstream of the primary transfer position.

  The image forming apparatus 1 also includes a marking unit 70 that can be pulled out in the axial direction of the developing device 12 with respect to the main body of the image forming apparatus 1. Each developing device 12, each contact type charging device 13, and each cleaning device 14 are mounted.

  The surface of the photosensitive drum 11 is uniformly charged by the contact charging device 13. The surface of the photosensitive drum 11 uniformly charged by the contact charging device 13 is irradiated with laser light (not shown) to form an electrostatic latent image on the surface of the photosensitive drum 11. The developing device 12 employs a two-component developing system, and the developing device 12 contains a two-component developer composed of a magnetic carrier and toner supplied from the toner cartridge 15. This two-component developer corresponds to an example of the two-component developer referred to in the present invention. Further, the developing device 12 is provided with a developing roll 121 corresponding to an example of a developer carrier according to the present invention. On the peripheral surface of the developing roll 121, a developer layer (so-called magnetic layer) in which a magnetic carrier to which toner adheres is formed is formed, and the toner is a photosensitive drum carrying an electrostatic latent image from the developer layer. 11 surface. The electrostatic latent image is developed upon receipt of toner and becomes a toner image.

  A transfer bias having a polarity opposite to the polarity of the toner is applied to the primary transfer roll 20, and the toner image formed on the surface of the photosensitive drum 11 moves from the surface of the photosensitive drum to the surface of the intermediate transfer belt 30. To do. The toner images formed by the respective toner image forming units 10 become color toner images that overlap one on the intermediate transfer belt 30.

  The batch transfer device 40 includes a secondary transfer roll 41 disposed in pressure contact with the toner image carrying surface side of the intermediate transfer belt 30 and a backup roll 42 disposed on the back side of the intermediate transfer belt 30. The intermediate transfer belt 30 is sandwiched between two rolls 41 and 42. Between these two rolls 41 and 42 is a secondary transfer position.

  Further, the image forming apparatus 1 shown in FIG. 1 is provided with a paper tray 60, and the paper stored in the paper tray 60 is sent to the secondary transfer position at a predetermined timing. At the secondary transfer position, the overlapping color toner images on the intermediate transfer belt 30 are transferred onto the fed paper. The fixing device 50 includes a fixing roll 51 having a heating mechanism 511 and a pressure roll 52 provided so as to face the fixing roll 51. A sheet that has passed the secondary transfer position is conveyed between the fixing roll 51 and the pressure roll 52 facing each other. The toner constituting the color toner image on the paper is melted and fixed on the paper by the heating mechanism 511 of the fixing roll 51.

  Here, since the developing device 12 incorporated in the image forming apparatus 1 shown in FIG. 1 corresponds to an embodiment of the present invention as described above, the developing device 12 will be described in detail below. .

  FIG. 2 is a cross-sectional view of a part of the toner image forming unit shown in FIG.

  FIG. 2 shows a photosensitive drum 11, a developing device 12, a contact charging device 13, and a cleaning device 14 that rotate in the clockwise arrow A direction as shown in FIG.

  The developing device 12 includes the developing roller 121 described above that rotates in the counterclockwise arrow B direction, and a developer stirring member 122 that stirs the two-component developer contained in the developing device 12. A seal roll 123 that rotates in the clockwise arrow C direction, a scraper 124 having a long plate shape, and an elastic member 125 are also provided.

  The developing roller 121 provided in the developing device 12 is disposed so as to contact the photosensitive drum 11 in the developing region D. In the developing device 12, the developer agitating member 122 agitates a two-component developer composed of a magnetic carrier and a toner (not shown) so that the toner adheres to the carrier, and the toner adhering to the carrier adheres to the carrier. The developer roll 121 is supplied as it is, and developer spikes are formed on the surface of the developer roll 121. The developer spikes thus formed are fed into the development region D by the rotation of the developing roll 121, and the toner adhering to the carrier is supplied to the surface of the photosensitive drum 11 carrying the electrostatic latent image. Is done. The electrostatic latent image is developed upon receipt of toner and becomes a toner image. In addition, the developed carrier is rotated in the direction of arrow B while forming a spike on the surface of the developing roll 121 and returned to the inside of the developing device 12.

  Here, floating toner is generated in the vicinity of the developing region (hereinafter, this floating toner is referred to as cloud toner). If the cloud toner is not collected, the developing device itself or the inside of the image forming apparatus is contaminated by the cloud toner, or the cloud toner However, in the developing device 12 of the present embodiment, such a problem is caused by the cloud toner collecting means described below. Has been avoided.

  The seal roll 123 is disposed downstream of the developing region D in the rotation direction of the photosensitive drum 11 so as to be spaced apart from the outer peripheral surface of the photosensitive drum 11 by a predetermined distance, and the cloud roller is supplied while rotating in the arrow C direction. Adsorb to the surface. The seal roll 123 corresponds to an example of an adsorption roll according to the present invention. Further, an upper film seal 128 is also provided on the upstream side of the developing region D in the rotational direction of the photosensitive drum 11, and cloud toner is prevented from scattering outside the developing device 12 on the upstream side in the rotational direction. ing.

  The scraper 124 is provided with a long edge in contact with the surface of the seal roll 123, and the toner adsorbed on the surface of the seal roll 123 is scraped off by the scraper 124 and returned to the inside of the developing device 12. It is.

  In addition, elastic members 125 are disposed on the opposite sides of the seal roll 123 at both end portions of the scraper 124 in the plate shape. The elastic member 125 corresponds to an example of the elastic member referred to in the present invention.

  Next, the shape and arrangement of the elastic member 125 will be described with reference to FIG.

  3 is a view of the seal roll, the scraper, and the elastic member shown in FIG. 2 as viewed from the left side of FIG.

  As shown in FIG. 3, the elastic member 125 is a right-angled triangle member, and is disposed so that an inclined side 125 a of the right-angled triangle facing the upstream side in the rotation direction of the seal roll 123 is inclined toward the center side of the scraper 124. ing. Accordingly, the scraped toner is surely guided to the inside of the developing device 12 by the oblique side 125a of the elastic member 125, so that the toner scraped and collected leaks out of the developing device 12. Is prevented. In the present embodiment, urethane having a thickness of 2 mm is applied as the elastic member 125.

  Further, in the present embodiment, since the toner scraped off at both end portions of the plate shape of the scraper 124 is avoided from staying in the vicinity of both end portions, the operation of pulling out and pushing in the marking unit 70 described above is performed. This prevents the toner from leaking out of the developing device 12 from the gap between the housing of the developing device 12 and the scraper 124.

  Above, description of 1st Embodiment of this invention is complete | finished.

  Next, the second embodiment in which the elastic member is incorporated into the developing device at a position different from the position described in the first embodiment as the elastic member in the present invention, and the first embodiment described above will be described. A third embodiment in which an elastic member having a shape different from the above shape is incorporated will be described.

  Note that the second and third embodiments described below have substantially the same device configuration as the device configuration described in the first embodiment, and therefore pay attention to the differences from the first embodiment, and the same elements are not described. The same reference numerals are given and description thereof is omitted.

  FIG. 4 is a schematic diagram of an elastic member according to the second embodiment.

  The elastic member 126 is a right-angled triangular member as in the first embodiment described above, and an oblique side 126a of the right-angled triangle facing the upstream side in the rotation direction of the seal roll 123 is inclined toward the center side of the scraper 124. At the same time, the scraper 124 is disposed so as to intersect the short side 124a. Accordingly, the scraped toner is more reliably guided to the inside of the developing device 12.

  FIG. 5 is a schematic diagram of an elastic member according to the third embodiment.

  The elastic member 127 is a rectangular member. Even in such a shape, the toner scraped off from the seal roll 123 that adsorbs the cloud toner on the surface of both ends of the plate shape of the scraper 124 having a long plate shape is removed from the developing device 12. Since the toner is guided to the inside, the toner collected by scraping is prevented from leaking out of the developing device 12.

  In each of the above-described embodiments, the two-component developer is exemplified as an example of the developer referred to in the present invention. However, the developer referred to in the present invention is not limited to this, and may be a developer including toner. That's fine.

1 is a schematic configuration diagram of an image forming apparatus incorporating a developing device corresponding to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of the toner image forming unit shown in FIG. 1. It is the figure which looked at the seal roll, scraper, and elastic member shown in FIG. 2 from the left side of FIG. It is a schematic diagram of the elastic member of 2nd Embodiment. It is a schematic diagram of the elastic member of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Toner image forming unit 11 Photoconductor drum 12 Developing apparatus 121 Developing roll 122 Developer stirring member 123 Seal roll 124 Scraper 124a Short side 125 Elastic member 126 Elastic member 126a Side 127 Elastic member 128 Upper film seal 13 Contact type Charging device 14 Cleaning device 15 Toner cartridge 16 Reserve tank 20 Primary transfer roll 30 Intermediate transfer belt 31 Support roll 40 Batch transfer device 41 Secondary transfer roll 42 Backup roll 50 Fixing device 51 Fixing roll 511 Heating mechanism 52 Pressure roll 60 Paper tray 70 Marking unit

Claims (4)

A developer containing toner, which is arranged so as to be close to or in contact with a latent image carrier that carries an electrostatic latent image and rotates in a predetermined direction in a predetermined development area, is supported on the development area. A developer carrier for developing the electrostatic latent image with toner by supplying a developer;
Rotating in the predetermined direction, adsorbing the floating toner disposed on the surface of the latent image carrier on the downstream side in the rotation direction of the latent image carrier from the developing region so as to be spaced apart from the outer peripheral surface of the latent image carrier. An adsorption roll;
A scraper that has a long plate shape, a long edge of the plate shape is in contact with the surface of the suction roll, and scrapes off the floating toner adsorbed on the surface;
A developing device comprising: an elastic member provided at each of both end portions of the plate shape on the opposite side to the suction roll of the scraper.   The developing device according to claim 1, wherein the elastic member has an end facing the upstream side in the rotation direction of the suction roll inclined toward the center side of the scraper.   2. The elastic member is characterized in that an end of the suction roll facing the upstream side in the rotation direction is inclined toward the center side of the scraper and intersects the short side of the scraper. Development device.   The developing device according to claim 1, wherein the developer is a two-component developer including a magnetic carrier and a toner.

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