JP2010097035A - Development apparatus and image forming apparatus using the same - Google Patents

Abstract

In a developing device, there is provided a developing device that prevents toner aggregation at the tip of a scraper and does not cause image unevenness over a long period of time, and an image forming apparatus using the developing device.
A developing roller that carries a developer including toner and a magnetic carrier and supplies the toner to a photosensitive drum 3 on which an electrostatic latent image is formed, and the developing roller 114 faces the photosensitive drum 3. And a scraper 118 that is disposed on the downstream side in the rotation direction of the developing roller 114 from the closest position 31 and scrapes off the developer carried on the developing roller 114. In the developing device, the axis of the developing roller 114 It is arranged to be rotatable around an axis parallel to the direction, and is driven to rotate in the same direction as the rotation direction of the developing roller 114.
[Selection] Figure 2

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus using the same, and more particularly to a developing device that handles a developer including a toner and a magnetic carrier employed in an image forming apparatus that forms an image using toner by electrophotography. And an image forming apparatus using the same.

  Conventional image forming apparatuses using electrostatic electrophotography such as copiers, printers, and facsimiles generally include charging, exposure, development, transfer, cleaning, static elimination, and fixing processes.

  In the step of forming an image, for example, the surface of the photosensitive drum that is rotationally driven by the charging device is uniformly charged, and the surface of the photosensitive member charged by the exposure device is irradiated with laser light to form an electrostatic latent image. Subsequently, the electrostatic latent image on the photosensitive drum is developed by the developing device, and a toner image is formed on the surface of the photosensitive drum.

  In the transfer and fixing process, the toner image on the photosensitive drum is transferred onto the transfer material by the transfer device, and then the toner image is heated together with the transfer material by the fixing device, whereby the toner image is fixed on the transfer material. The

  Further, the transfer residual toner remaining on the surface of the photosensitive drum is removed by a cleaning device and collected in a predetermined collection unit. Residual charges are removed from the surface of the photosensitive drum after being cleaned by a static eliminator to prepare for the next image formation.

  In the image forming apparatus configured as described above, as the developer for developing the electrostatic latent image on the photosensitive drum, a one-component developer composed only of toner or a two-component developer composed of toner and carrier is generally used. It is done.

  Since the one-component developer does not use a carrier, it does not require a stirring mechanism for uniformly mixing the toner and the carrier, and has an advantage that the developing device is simplified. However, since the one-component developer has drawbacks such as the toner charge amount being difficult to stabilize, a two-component developer is generally used for a high-speed image forming apparatus or a color image forming apparatus.

  In the two-component developer, when the toner content in the two-component developer (hereinafter referred to as “toner concentration”) changes, the image density changes. It is necessary to develop the electrostatic latent image formed on the surface. Therefore, in order to make the toner density uniform, the carrier of the two-component developer and the toner are sufficiently stirred, and then the toner is supplied to the surface of the photosensitive drum by the developing roller.

  However, when the two-component developer that has consumed the toner supplied for development is transported to the surface of the photosensitive drum again without leaving the surface of the developing roller, the development memory becomes nonuniform in image density. There was a problem that occurred.

  The development memory refers to a reversal image (an image in which the density of an image formed on the photosensitive drum is reversed) generated on the development roller in the development area, and is developed again by the rotation of the development roller while remaining on the development roller. This is a phenomenon in which a reverse image is developed on a photosensitive drum when conveyed to an area.

In order to solve this problem, as a conventional technique, for example, the two-component developer supplied to the surface of the photosensitive drum is prevented from being conveyed again to the surface of the photosensitive drum without leaving the developing roller. A developing device provided with a scraper that scrapes the two-component developer from the surface of the developing roller is disclosed (see Patent Document 1).
JP 2000-321870 A

  However, when the scraper is provided in the developing device, the two-component developer aggregates at the tip of the scraper, and there is a problem that image unevenness due to filming of the toner component on the surface of the developing roller occurs.

  The present invention has been made in view of the above-described conventional problems. In the developing device, the developing device prevents toner aggregation at the tip of the scraper and does not cause image unevenness over a long period of time, and image formation using the developing device. An object is to provide an apparatus.

  The developing device and the image forming apparatus using the same according to the present invention for solving the above-described problems are as follows.

  The present invention provides a developing roller that carries a developer including toner and a magnetic carrier and supplies toner to a photosensitive drum on which an electrostatic latent image is formed, and a position of the developing roller that faces the photosensitive drum. And a scraper that scrapes off the developer carried on the developing roller and disposed downstream of the developing roller in the rotation direction, and rotates the scraper around an axis parallel to the axial direction of the developing roller. It arrange | positions so that it is possible and it rotationally drives to the same direction as the rotation direction of the said developing roller.

  Further, according to the present invention, as the configuration of the scraper, a rotation shaft arranged in parallel with the developing roller axial direction, a radial shaft provided from the rotation shaft, and a long extension along the axial direction of the rotation shaft. And a plurality of scraping blades.

  In the present invention, it is preferable that the scraping blade is a rectangular plate-like member provided in parallel to the axial direction of the rotating shaft.

  In the present invention, it is preferable that the scraper is a columnar member provided on the surface thereof with a groove portion provided in parallel along the axial direction of the rotation shaft.

  In the present invention, it is preferable that the groove is a V-shaped groove provided in parallel along the axial direction of the rotating shaft.

  In the present invention, it is preferable to use an ultrasonic motor as a drive source for rotating the scraper.

  The present invention also provides a photosensitive drum on which an electrostatic latent image is formed, a charging device that charges the surface of the photosensitive drum, an exposure device that forms an electrostatic latent image on the surface of the photosensitive drum, and a photosensitive member. A developing device for supplying a developer to an electrostatic latent image on the drum surface to form a toner image, a transfer device for transferring the toner image on the surface of the photosensitive drum to a recording medium, and a fixing device for fixing the toner image to the recording medium And an image forming apparatus that forms an image using toner by an electrophotographic method, wherein the developing device according to any one of claims 1 to 6 is used as the developing device. Is.

  According to the present invention, a developing roller that carries a developer containing toner and a magnetic carrier and supplies toner to a photosensitive drum on which an electrostatic latent image is formed, and the developing roller facing the photosensitive drum. And a scraper that scrapes off the developer carried on the developing roller and is disposed downstream of the position where the developing roller rotates, and the scraper is rotated about an axis parallel to the axial direction of the developing roller. Since the effect of scraping off the developer from the developing roller is increased, the effect of suppressing the development memory can be improved. . Furthermore, the retention of the developer can be suppressed, and the toner component can be prevented from fusing to the scraper surface and the developer can be prevented from aggregating, so that the occurrence of image unevenness can be suppressed.

  Further, according to the present invention, the scraper is configured such that the rotation shaft disposed in parallel to the developing roller axial direction, the rotation shaft is provided radially from the rotation shaft, and extends long along the axial direction of the rotation shaft. By providing the plurality of scraping blades provided, the developer conveying ability can be improved by the rotating scraping blades, that is, the developer scraping effect can be enhanced.

  According to the invention, the scraping blade is a rectangular plate-like member provided in parallel to the axial direction of the rotating shaft, so that the rotating scraping blade is in the developer transport direction. On the other hand, the developer transport efficiency can be increased because the developer is arranged vertically.

  Further, according to the present invention, the scraper is a columnar member provided with a groove portion provided in parallel along the axial direction of the rotation shaft on the surface thereof, so that the size and rigidity can be increased.

  Further, according to the present invention, the groove portion is a V-shaped groove provided in parallel along the axial direction of the rotation shaft, whereby the effect of scraping and transporting the developer can be enhanced.

  Further, according to the present invention, the ultrasonic motor is used as a drive source for rotating the scraper, so that the scraper vibrates ultrasonically, so that it is possible to prevent the developer from being fused to the scraper.

  Further, according to the present invention, a photosensitive drum on which an electrostatic latent image is formed, a charging device that charges the surface of the photosensitive drum, an exposure device that forms an electrostatic latent image on the surface of the photosensitive drum, A developing device for supplying a developer to the electrostatic latent image on the surface of the photosensitive drum to form a toner image, a transfer device for transferring the toner image on the surface of the photosensitive drum to a recording medium, and fixing the toner image to the recording medium An image forming apparatus comprising a fixing device and forming an image using toner by an electrophotographic method, wherein the developing device according to any one of claims 1 to 6 is used as the developing device. The effect of scraping off the developer from the developing roller by the characteristic scraper provided in the developing device can be enhanced, and at the same time, the occurrence of the development memory is suppressed, and at the same time, the fusion of the toner component to the scraper surface and the developer It is possible to suppress the current, it is possible to suppress the occurrence of image unevenness. As a result, it is possible to realize an image forming apparatus that suppresses development memory and prevents image unevenness over a long period of time.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is an example of an embodiment for carrying out the invention, and is an explanatory view showing the overall configuration of an image forming apparatus using a developing device according to an embodiment of the present invention.

  In the present embodiment, as shown in FIG. 1, a photosensitive drum 3 on which an electrostatic latent image is formed, a charger (charging device) 5 for charging the surface of the photosensitive drum 3, and the surface of the photosensitive drum 3 An exposure unit (exposure device) 1 that forms an electrostatic latent image on the surface, a developing device 2 that forms a toner image by supplying toner to the electrostatic latent image on the surface of the photosensitive drum 3, and a toner supply to the developing device 2 Toner hopper (toner supply device) 101, an intermediate transfer belt unit (transfer device) 8 for transferring the toner image on the surface of the photosensitive drum 3 to a recording medium, and a fixing unit (fixing device) for fixing the toner image on the recording medium. In the image forming apparatus 100 that forms an image using toner by an electrophotographic method, the developing device 2 according to the present invention is employed as the developing device 2.

  The image forming apparatus 100 forms a multicolor or single color image on a predetermined sheet (recording paper, recording medium) according to image data transmitted from the outside. A scanner or the like may be provided above the image forming apparatus 100.

First, the overall configuration of the image forming apparatus 100 will be described.
As shown in FIG. 1, the image forming apparatus 100 handles image data for each color component of black (K), cyan (C), magenta (M), and yellow (Y). An image and a yellow image are formed, and a color image is formed by superimposing the images of the respective color components.

  Accordingly, in the image forming apparatus 100, as shown in FIG. 1, the developing device 2 (2a, 2b, 2c, 2d) and the photosensitive drum 3 (3a, 3b, 3c) are formed so that images of the respective color components are formed. , 3d), four chargers 5 (5a, 5b, 5c, 5d) and four cleaner units 4 (4a, 4b, 4c, 4d). In other words, four image forming stations (image forming units) each including the developing device 2, the photosensitive drum 3, the charger 5, and the cleaner unit 4 are provided.

  The symbols a to d indicate that a is a member for forming a black image, b is a member for forming a cyan image, c is a member for forming a magenta image, and d is a member for forming a yellow image. It is a thing. Further, the image forming apparatus 100 includes an exposure unit 1, a fixing unit 12, a sheet conveyance path S, a paper feed tray 10, and a paper discharge tray 15.

The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential.
As the charger 5, a contact brush type charger or a non-contact charger type charger may be used in addition to the contact roller type charger shown in FIG.

  As shown in FIG. 1, the exposure unit 1 is a laser scanning unit (LSU) including a laser irradiation unit and a reflection mirror. However, in addition to the laser scanning unit, the exposure unit 1 may be an EL (electroluminescence) in which light emitting elements are arranged in an array or an LED writing head. The exposure unit 1 exposes the charged photosensitive drum 3 according to the input image data, thereby forming an electrostatic latent image corresponding to the image data on the surface of the photosensitive drum 3.

  The developing device 2 visualizes (develops) the electrostatic latent image formed on the photosensitive drum 3 with one of K, C, M, and Y toners. The developing device 2 (2a, 2b, 2c, 2d) includes a toner hopper 101 (101a, 101b, 101c, 101d), a toner transfer mechanism 102 (102a, 102b, 102c, 102d), and a developing tank (developer container) 111. (111a, 111b, 111c, 111d).

  The toner hopper 101 is arranged on the H direction side of the developing tank 111 and stores unused toner (powder toner). The toner is supplied from the toner hopper 101 to the developing tank 111 via the toner transfer mechanism 102.

  The cleaner unit 4 removes and collects the toner remaining on the surface of the photosensitive drum 3 after the development and image transfer processes.

  An intermediate transfer belt unit 8 is disposed above the photosensitive drum 3. The intermediate transfer belt unit 8 includes an intermediate transfer roller 6 (6a, 6b, 6c, 6d), an intermediate transfer belt 7, an intermediate transfer belt driving roller 71, an intermediate transfer belt driven roller 72, an intermediate transfer belt tension mechanism 73, and an intermediate transfer. A belt cleaning unit 9 is provided.

  The intermediate transfer belt 6, the intermediate transfer belt drive roller 71, the intermediate transfer belt driven roller 72, and the intermediate transfer belt tension mechanism 73 stretch the intermediate transfer belt 7 and rotationally drive the intermediate transfer belt 7 in the direction of arrow B in FIG. It is something to be made.

  The intermediate transfer roller 6 is rotatably supported by an intermediate transfer roller mounting portion in the intermediate transfer belt tension mechanism 73 of the intermediate transfer belt unit 8. A transfer bias for transferring the toner image on the photosensitive drum 3 onto the intermediate transfer belt 7 is applied to the intermediate transfer roller 6.

  The intermediate transfer belt 7 is provided so as to be in contact with each photosensitive drum 3. A color toner image (multicolor toner image) is formed on the intermediate transfer belt 7 by sequentially superimposing and transferring the toner images of the respective color components formed on the photosensitive drum 3. The intermediate transfer belt 7 is formed in an endless shape using a film having a thickness of, for example, about 100 μm to 150 μm.

  Transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 7 is performed by the intermediate transfer roller 6 in contact with the back side of the intermediate transfer belt 7. A high voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 6 in order to transfer the toner image.

  The intermediate transfer roller 6 is formed based on a metal (for example, stainless steel) shaft having a diameter of, for example, 8 to 10 mm, and the surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, the intermediate transfer roller 6 can uniformly apply a high voltage to the intermediate transfer belt 7. In this embodiment, a roller-shaped transfer electrode (intermediate transfer roller 6) is used as the transfer electrode, but a brush or the like can also be used.

  As described above, the electrostatic latent images on the respective photosensitive drums 3 are visualized with toners corresponding to the respective color components to become toner images, and these toner images are superimposed and laminated on the intermediate transfer belt 7. As described above, the stacked toner images are moved to a contact position (transfer portion) between the conveyed paper and the intermediate transfer belt 7 by the rotation of the intermediate transfer belt 7, and the transfer roller disposed at this position is moved. 11 is transferred onto the paper. In this case, the intermediate transfer belt 7 and the transfer roller 11 are pressed against each other at a predetermined nip, and a voltage for transferring the toner image onto the sheet is applied to the transfer roller 11. This voltage is a high voltage having a polarity (+) opposite to the charging polarity (−) of the toner.

  In order to obtain the nip constantly, either the transfer roller 11 or the intermediate transfer belt drive roller 71 is made of a hard material such as metal, and the other is a soft material such as an elastic roller (elastic rubber roller or foamable resin roller). Etc.).

  The toner adhering to the intermediate transfer belt 7 due to the contact between the intermediate transfer belt 7 and the photosensitive drum 3 and the toner image remaining on the intermediate transfer belt 7 without being transferred when the toner image is transferred from the intermediate transfer belt 7 to the sheet. The toner is removed and collected by the intermediate transfer belt cleaning unit 9 because it causes toner color mixing in the next step.

  The intermediate transfer belt cleaning unit 9 is provided with a cleaning blade (cleaning member) that contacts the intermediate transfer belt 7. The portion of the intermediate transfer belt 7 that is in contact with the cleaning blade is supported by the intermediate transfer belt driven roller 72 from the back side.

  The paper feed tray 10 is for storing sheets (for example, recording paper) used for image formation, and is provided below the image forming unit and the exposure unit 1. On the other hand, a paper discharge tray 15 provided in the upper part of the image forming apparatus 100 is for placing printed sheets face down.

  Further, the image forming apparatus 100 is provided with a sheet conveyance path S for guiding the sheet of the paper feed tray 10 and the sheet of the manual feed tray 20 to the paper discharge tray 15 via the transfer unit and the fixing unit 12. . The transfer unit is located between the intermediate transfer belt driving roller 71 and the transfer roller 11.

  Further, a pickup roller 16 (16a, 16b), a registration roller 14, a transfer unit, a fixing unit 12, a conveyance roller 25 (25a to 25h), and the like are arranged in the sheet conveyance path S.

  The conveyance rollers 25 are small rollers for promoting and assisting conveyance of the sheet, and a plurality of conveyance rollers 25 are provided along the sheet conveyance path S. The pickup roller 16 a is a pull-in roller that is provided at the end of the paper feed tray 10 and supplies sheets one by one from the paper feed tray 10 to the sheet conveyance path S. The pickup roller 16 b is a drawing roller that is provided near the manual feed tray 20 and supplies sheets from the manual feed tray 20 to the sheet conveyance path S one by one. The registration roller 14 temporarily holds the sheet conveyed in the sheet conveyance path S, and conveys the sheet to the transfer unit at a timing when the leading edge of the toner image on the intermediate transfer belt 7 and the leading edge of the sheet are aligned.

  The fixing unit 12 includes a heat roller 81, a pressure roller 82, and the like. The heat roller 81 and the pressure roller 82 rotate with the sheet interposed therebetween. The heat roller 81 is controlled by a control unit (not shown) so as to have a predetermined fixing temperature. This control unit controls the temperature of the heat roller 81 based on a detection signal from a temperature detector (not shown).

  The heat roller 81 heat-presses the sheet together with the pressure roller 82 to melt, mix, and press the color toner images transferred to the sheet, and heat-fix the sheet. The sheet on which the multicolor toner image (each color toner image) is fixed is conveyed to the reverse sheet discharge path of the sheet conveyance path S by the plurality of conveyance rollers 25 and is reversed (the multicolor toner image is on the lower side). Are discharged onto the paper discharge tray 15.

Next, the sheet conveying operation by the sheet conveying path S will be described.
As shown in FIG. 1, the image forming apparatus 100 is provided with a paper feed tray 10 that stores sheets in advance and a manual feed tray 20 that is used when printing a small number of sheets as described above. Pickup rollers 16 (16a, 16b) are disposed on both trays, and the pickup rollers 16 supply sheets one by one to the sheet conveyance path S.

  In the case of single-sided printing, the sheet conveyed from the sheet feeding tray 10 is conveyed to the registration roller 14 by the conveyance roller 25a in the sheet conveyance path S, and is stacked on the leading edge of the sheet and the intermediate transfer belt 7 by the registration roller 14. Then, the toner image is conveyed to a transfer portion (contact position between the transfer roller 11 and the intermediate transfer belt 7) at a timing when the leading edge of the toner image is aligned. In the transfer portion, a toner image is transferred onto the sheet, and this toner image is fixed on the sheet by the fixing unit 12. Thereafter, the sheet is discharged onto the discharge tray 15 from the discharge roller 25c via the conveyance roller 25b.

  Further, the sheet conveyed from the manual feed tray 20 is conveyed to the registration roller 14 by a plurality of conveying rollers 25 (25f, 25e, 25d). Subsequent sheet conveyance operations are discharged to the sheet discharge tray 15 through a process similar to that for the sheets supplied from the sheet feed tray 10 described above.

  On the other hand, in the case of double-sided printing, the trailing edge of the sheet that has completed single-sided printing and passed through the fixing unit 12 as described above is chucked by the paper discharge roller 25c. Next, the sheet is guided to the conveying rollers 25g and 25h by the reverse rotation of the paper discharge roller 25c, and after the printing on the back surface is again performed through the registration roller 14, it is discharged to the paper discharge tray 15.

Next, the characteristic developing device 2 of the present embodiment will be described with reference to the drawings.
2 is a cross-sectional view showing a configuration of a developing device constituting the image forming apparatus according to the present embodiment, and FIG. 3 is a cross-sectional view taken along the line AA in FIG.

  As shown in FIG. 2, the developing device 2 has a developing roller (developer carrying member) 114 disposed in the developing tank 111 so as to face the photosensitive drum 3. 3 is a device for supplying (developing) an electrostatic latent image formed on the surface of the photosensitive drum 3 by supplying toner to the surface of the photosensitive drum 3.

  2 and 3, in addition to the developing roller 114, the developing device 2 includes a developing tank 111, a developing tank cover 115, a toner supply port 115a, a doctor blade 116, a first conveying member 112, and a second conveying member. 113, a partition plate (partition wall) 117, and a characteristic scraper 118.

  The developing tank 111 is a tank for storing a two-component developer containing toner and carrier (hereinafter simply referred to as “developer”). The developing tank 111 is provided with a developing roller 114, a first conveying member 112, a second conveying member 113, and the like. Note that the carrier of this embodiment is a magnetic carrier having magnetism.

  Further, as shown in FIG. 2, a detachable developing tank cover 115 is provided above the developing tank 111. Further, the developing tank cover 115 is formed with a toner supply port 115 a for supplying unused toner to the developing tank 111.

  As shown in FIGS. 1 and 2, the toner contained in the toner hopper 101 is supplied to the developing tank 111 via the toner transfer mechanism 102 and the toner supply port 115a.

  The developing roller 114 is a rotating magnet roller, and as shown in FIG. 2, the developer in the developing tank 111 is pumped up and carried on the surface, and toner contained in the developer carried on the surface is photoreceptor drum 3. To supply. A doctor blade (layer thickness regulating blade) 116 is disposed at a position close to the surface of the developing roller 114.

  As shown in FIGS. 2 and 3, the first transport member 112 and the second transport member 113 are formed by a screw auger including spiral transport blades 112 a and 113 a for stirring and transporting the developer in the developing tank 111. The shaft 112b, 113b is driven to rotate by driving of driving means (not shown) such as a motor that is configured and transmitted via the driving gears 112c, 113c, so that the developer is stirred and conveyed. Yes.

  The first transport member 112 and the second transport member 113 are arranged in parallel so that their peripheral surfaces face each other via the partition plate 117 and their axes are parallel to each other, and rotate in opposite directions. Is set to Then, as shown in FIG. 3, the first transport member 112 transports the developer in the arrow X direction, and the second transport member 113 transports the developer in the arrow Y direction opposite to the arrow X direction. Is set to

  In the developing tank 111, a partition plate 117 is disposed between the first transport member 112 and the second transport member 113. The partition plate 117 extends in parallel with each axial direction (each rotational axis direction) of the first transport member 112 and the second transport member 113. The interior of the developing tank 111 is partitioned by a partition plate 117 into a first transport path P in which the first transport member 112 is disposed and a second transport path Q in which the second transport member 113 is disposed.

  The partition plate 117 is disposed away from the inner wall surface of the developing tank 111 at both axial ends of the first transport member 112 and the second transport member 113. Thereby, in the developing tank 111, a communication path that connects the first transport path P and the second transport path Q is formed in the vicinity of both axial ends of the first transport member 112 and the second transport member 113. ing. In the following, as shown in FIG. 3, the communication path formed on the arrow X direction side is referred to as a first communication path a, and the communication path formed on the arrow Y direction side is referred to as a second communication path b.

  In the present embodiment, the toner replenishing port 115a is an area in the first transport path P and is formed at a position on the arrow X direction side of the second communication path b. That is, in the first transport path P, the toner is replenished downstream of the second communication path b.

  In the developing tank 111, the first transport member 112 and the second transport member 113 are rotationally driven by a driving means (not shown) such as a motor to transport the developer. Specifically, in the first transport path P, the developer is transported in the direction of arrow X while being stirred by the first transport member 112 and reaches the first communication path a. The developer that has reached the first communication path a passes through the first communication path a and is conveyed to the second conveyance path Q. On the other hand, in the second transport path Q, the developer is transported in the direction of arrow Y while being stirred by the second transport member 113 and reaches the second communication path b. Then, the developer that has reached the second communication path b passes through the second communication path b and is conveyed to the first conveyance path P. That is, the first transport member 112 and the second transport member 113 transport the developer in the opposite directions while stirring the developer.

  In this way, the developer passes through the first conveyance path P, the first communication path a, the second conveyance path Q, and the second communication path b in the developing tank 111 from the first conveyance path P to the first communication path. Circulating movement is performed in the order of a → second conveyance path Q → second communication path b. Then, while the developer is being conveyed in the second conveyance path Q, the developer is carried on the surface by the rotation of the developing roller 114 and pumped up, and the toner in the developer that has been pumped up is transferred to the photosensitive drum 3. It moves and is consumed sequentially.

  In order to make up for the consumed toner, unused toner is replenished to the first transport path P from the toner replenishing port 115a. The replenished toner is mixed and agitated with the developer existing in the first conveyance path P.

Next, the configuration of the characteristic scraper 118 of the present embodiment will be specifically described with reference to the drawings.
FIG. 4 is a perspective view showing the overall configuration of the scraper constituting the developing device according to the present embodiment.

  As shown in FIG. 4, the scraper 118 is disposed so as to be rotatable about an axis parallel to the axial direction of the developing roller 114, and is driven to rotate in the same direction as the rotating direction of the developing roller 114. Specifically, the scraper 118 includes a rotating shaft 118a arranged in parallel to the developing roller axial direction, and a plurality of scrapers 118 that are provided radially from the rotating shaft 118a and extend long along the axial direction of the rotating shaft 118a. Scraping blade 118b.

  The rotating shaft 118a and the scraping blade 118b are both formed using a metal material. The rotating shaft 118a is rotatably supported by the developing tank 111. One end of the rotating shaft 118 a is connected to the ultrasonic motor 119 and is rotated by the ultrasonic motor 119.

  As shown in FIG. 4, the scraping blade 118b is composed of a rectangular plate-like member provided in parallel to the axial direction of the rotating shaft 118a. As shown in FIG. 2, the developing roller 114 and the photosensitive drum 3 is disposed in the vicinity of the outer peripheral surface of the developing roller 114 on the downstream side in the rotation direction of the developing roller from the closest position 31 to the position 3, and the developer is scraped off from the surface of the developing roller 114.

Next, the action of scraping off the developer from the developing roller 114 by the scraper 118 of the developing device 2 according to the present embodiment will be described with reference to the drawings.
FIG. 5 is an explanatory diagram showing a state in which the developer is scraped off from the developing roller by the scraper in the developing device of the present embodiment.

  In the developing device 2 of the present embodiment, as shown in FIG. 5, the developer supplied from the second conveying member 113 to the developing roller 114 passes through the gap with the doctor blade 116 and is then carried on the developing roller 114. As it is, it is conveyed to the position 31 closest to the photosensitive drum 3 and used for developing an electrostatic latent image formed on the surface of the photosensitive drum 3.

  The developed developer D is conveyed into the developing tank 111 while being carried on the developing roller 114, scraped off by the scraper 118, and returned to the upper portion of the second conveying member 113.

  That is, as shown in FIG. 5, the developer D scraped off from the developing roller 114 by the scraping blade 118b and accumulated on the scraper 118 has the same direction as the developing roller 114 (clockwise direction in the drawing). , It is transported away from the developing roller 114 and falls onto the second transport member 113.

  In this way, by rotating the scraper 118, the developer D collected from the surface of the developing roller 114 can be effectively dropped from the scraping blade 118b, so that the toner component is melted onto the surface of the scraping blade 118b. Adhesion and aggregation of developer D can be suppressed. Thereby, the developer D can be efficiently scraped off from the developing roller 114 by the scraping blade 118b.

  Since it comprised as mentioned above, according to this embodiment, in the image development apparatus 2, the rotation arrange | positioned in parallel with the axial direction of the developing roller 114 as a scraper which scrapes off the developer carry | supported by the developing roller 114 A scraper 118 provided with a shaft 118a and a plurality of rectangular scraping blades 118b that are provided radially from the rotating shaft 118a and that are long in the axial direction is disposed close to the developing roller 114, and the developing roller 114 rotates. Since the developer D collected from the developing roller 114 can be transported without staying on the scraper 118 by being rotated in the same direction as the direction, the toner component can be fused to the surface of the scraping blade 118b. Aggregation of developer D can be suppressed. As a result, the developer D can be efficiently scraped off from the developing roller 114 by the scraping blade 118b, thereby preventing development memory from being generated due to the developer D remaining on the developing roller 114, and for a long period of time. Thus, an image forming apparatus that does not cause image unevenness can be realized.

  In the present embodiment, the scraping blade 118b is formed of a rectangular plate-shaped member and is provided in parallel to the axial direction of the rotating shaft 118a. Therefore, the rotating scraping blade 118b transports the developer D. Since it is arranged perpendicular to the direction, the transport efficiency of the developer D can be increased.

  The present invention is not limited to the configuration of the scraper 118 described above. For example, as a modified example, as shown in FIGS. 6A and 6B, the developing device 2 is replaced with the scraper 118. The surface may be provided with a cylindrical member scraper 218 provided with grooves 218a provided in parallel along the axial direction of the rotating shaft. By comprising in this way, a small and highly rigid scraper is obtained.

  As another modified example, as shown in FIGS. 7A and 7B, in the developing device 2, a V-shaped groove provided on the surface in parallel along the axial direction of the rotating shaft instead of the scraper 118. A cylindrical member scraper 318 provided with 318a may be provided. With this configuration, it is possible to obtain a scraper that is highly effective in scraping and transporting the developer, and that is small and has high rigidity.

  In the above-described embodiment and modification, the example in which the developing device 2 according to the present invention is applied to the image forming apparatus 100 as shown in FIG. 1 has been described. However, the toner carried on the developing roller after development is removed by a scraper. As long as the image forming apparatus is equipped with a developing device that is scraped and collected, the image forming apparatus is not limited to the image forming apparatus and the copying machine configured as described above, and can be developed to other image forming apparatuses. is there.

  As described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope not departing from the gist of the present invention are also included in the technical scope of the present invention.

1 is an explanatory diagram illustrating an overall configuration of an image forming apparatus in which a developing device according to an embodiment of the present invention is used. FIG. 2 is a cross-sectional view illustrating a configuration of a developing device that constitutes the image forming apparatus. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2. It is a perspective view which shows the whole structure of the scraper which comprises the said developing device. FIG. 4 is an explanatory diagram illustrating a state in which the developer is scraped off from a developing roller by a scraper in the developing device. (A) is explanatory drawing which shows the structure of the modification of the scraper which concerns on embodiment of this invention, (b) is an enlarged front view which shows the structure of the said scraper. (A) is explanatory drawing which shows the structure of the other modification of the scraper which concerns on embodiment of this invention, (b) is an enlarged front view which shows the structure of the said scraper.

Explanation of symbols

2 Developing Device 3 Photosensitive Drum 31 Nearest Position 100 Image Forming Device 111 Developing Tank 112 First Conveying Member 113 Second Conveying Member 114 Developing Rollers 118, 218, 318 Scraper 118a Rotating Shaft 118b Scraping Blade 119 Ultrasonic Motor 218a Groove 318a V-shaped groove D Developer

Claims (7)

A developing roller that carries a developer including toner and a magnetic carrier and supplies the toner to a photosensitive drum on which an electrostatic latent image is formed, and the developing roller rotates from a position of the developing roller facing the photosensitive drum In a developing device comprising a scraper disposed on the downstream side in the direction and scraping off the developer carried on the developing roller,
The developing device, wherein the scraper is rotatably arranged around an axis parallel to the developing roller axial direction, and is driven to rotate in the same direction as the rotating direction of the developing roller.   The scraper includes a rotating shaft disposed in parallel to the developing roller axial direction, and a plurality of scraping blades provided radially from the rotating shaft and extending long along the axial direction of the rotating shaft; The developing device according to claim 1, further comprising:   The developing device according to claim 2, wherein the scraping blade is a rectangular plate-like member provided in parallel to the axial direction of the rotation shaft.   The developing device according to claim 1, wherein the scraper is a columnar member having a groove portion provided on a surface thereof in parallel along the axial direction of the rotation shaft.   The developing device according to claim 4, wherein the groove portion is a V-shaped groove provided in parallel along an axial direction of the rotation shaft.   The developing device according to claim 1, wherein an ultrasonic motor is used as a driving source for rotating the scraper. A photosensitive drum on which an electrostatic latent image is formed, a charging device for charging the surface of the photosensitive drum, an exposure device for forming an electrostatic latent image on the surface of the photosensitive drum, and an electrostatic latent image on the surface of the photosensitive drum An electrophotographic apparatus comprising: a developing device that supplies a developer to an image to form a toner image; a transfer device that transfers the toner image on the surface of the photosensitive drum to a recording medium; and a fixing device that fixes the toner image to the recording medium. In an image forming apparatus that forms an image using toner according to a method,
An image forming apparatus using the developing device according to claim 1 as the developing device.

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