JP2005275087A - Cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a cleaning device capable of restraining the defect of image quality caused by the scraped pieces of scraped toner. <P>SOLUTION: Since a scraper 44 is constituted of two circular-arc-shaped curved parts 44A and 44B where the cross sectional shape in the thickness direction (direction shown by an arrow W) of the edge parts 44S abutting on a detoning roll 42 is continued, the scraped pieces K of the toner T scraped by the scraper 44 are smaller than in the conventional manner. Therefore, even when the smaller scraped pieces K spill to the outside of the cleaning device, influence exerted on the image quality is small and the defect of the image quality is restrained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning device that applies a metal thin plate scraper to the surface of a rotating body that holds toner to scrape off the toner on the surface of the rotating body.

  In a cleaning device of an image forming apparatus, a metal scraper may be used to scrape off toner remaining on the surface of the photosensitive drum.

  In such a metal scraper, the elastic deformation of the tip portion is less than that of a scraper made of a material other than metal when contacting the photosensitive drum, so that the shape of the tip portion directly affects the cleaning performance. For this reason, for example, there is a scraper that forms a cross-sectional shape in the thickness direction of the tip portion in a concave shape as a whole to prevent toner slipping (see, for example, Patent Document 1).

However, when the cross-sectional shape is formed in a concave shape as a whole, the scraped piece of toner scraped off by the scraper becomes large. If such a scraping piece spills outside the cleaning device, it may appear as an image quality defect.
JP 2003-58006 A

  In view of the above-described facts, an object of the present invention is to provide a cleaning device that can suppress image quality defects caused by scraped pieces of scraped toner.

  The cleaning device of the present invention described in claim 1 is a cleaning device that applies a metal thin plate scraper to the surface of a rotating body holding toner and scrapes off the toner on the surface of the rotating body. Is characterized in that the cross-sectional shape in the thickness direction of the tip portion that contacts the rotating body is composed of a plurality of arcuate curved portions.

  Here, the rotator refers to a rotator that is provided in the image forming apparatus and holds toner on the surface thereof. For example, the rotator contacts the brush member that removes toner from the surface of the image carrier, intermediate transfer member, and image carrier. The collection roll etc. which are arrange | positioned are mentioned.

  According to the cleaning device of the first aspect of the present invention, the metal thin plate scraper is applied to the surface of the rotating body holding the toner to scrape off the toner on the surface of the rotating body. Here, since the scraper is composed of a plurality of arc-shaped curved portions in the thickness direction of the tip portion that contacts the rotating body, the scraped pieces of toner scraped off by the scraper become small. For this reason, even if this small scraping piece spills out of the cleaning device, the influence on the image quality is small and image quality defects can be suppressed.

  As described above, according to the cleaning device of the present invention, there is an excellent effect that image quality defects due to scraped pieces of toner scraped off can be suppressed.

  A cleaning device according to the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an image forming apparatus provided with a cleaning device. This image forming apparatus is used for an electrophotographic copying machine, a laser printer, and the like.

  As shown in FIG. 1, the image forming apparatus 10 includes a photosensitive drum 12 as an image carrier, and the photosensitive drum 12 rotates in a clockwise direction (arrow A direction) in FIG. On the circumference surrounding the photosensitive drum 12, the corotron 14, the exposure device 16, the developing device 18, the transfer belt 20, the pre-cleaning corotron 32, and the cleaning device 34 are clockwise (arrow A direction) in FIG. Are sequentially arranged.

  A corotron 14 is disposed diagonally above the photosensitive drum 12 so as to face the photosensitive drum 12. By this corotron 14, the surface 12A of the photosensitive drum 12 is negatively charged. An exposure device 16 is provided on the downstream side of the corotron 14. The exposure device 16 writes an image on the surface 12 A of the photosensitive drum 12 charged by the corotron 14, whereby a latent image is formed on the surface 12 A of the photosensitive drum 12.

  A developing device 18 is provided on the downstream side of the exposure device 16. The developing device 18 attaches yellow, magenta, cyan, and black toners to the surface 12A of the photosensitive drum 12 to form toner images of the respective colors, so that a Y image forming unit 18Y and an M image forming unit 18M are formed. The C image forming unit 18C and the BK image forming unit 18B are arranged circumferentially along the counterclockwise direction in FIG. The developing device 18 attaches toner to the latent image formed by the exposure device 16, so that a toner image is formed on the surface 12 </ b> A of the photosensitive drum 12.

  On the downstream side of the developing device 18, an endless belt-shaped transfer belt 20 that is in contact with the photosensitive drum 12 is provided. The transfer belt 20 is held in a tensioned state from the inside by the conveying rollers 19A, 19B, 19C, and 19D, and can be driven in the counterclockwise direction (arrow B direction) in FIG. At the position inside the transfer belt 20 and facing the photosensitive drum 12, the transfer belt 20 is positively charged and the toner on the surface 12 </ b> A of the photosensitive drum 12 is attracted to the outer surface of the transfer belt 20. A transfer roller 22 is provided. A positive voltage is applied to the primary transfer roller 22. Since the primary transfer roller 22 rotates while applying pressure to the transfer belt 20, the toner image formed on the surface 12 </ b> A of the photosensitive drum 12 is transferred to the transfer belt 20. Below the transfer belt 20 is a secondary transfer roller 24 that transfers the toner image formed on the transfer belt 20 onto the recording paper P by positively transferring the recording paper P and pressing it against the transfer belt 20. It is arranged.

  Below the transfer belt 20, a recording paper supply device 26 that supplies the recording paper P to the secondary transfer roller 24 is provided. The recording paper supply device 26 includes a pair of transport rollers 26A and 26A, and a guide slope 26B that guides the recording paper P transported by the transport rollers 26A and 26A toward the secondary transfer roller 24. On the discharge side of the recording paper P by the secondary transfer roller 24, a fixing device 28 for fixing the toner image on the recording paper P is provided. The fixing device 28 includes a pair of fixing rollers 28A and 28A for fixing the toner image by heating and pressing the recording paper P on which the toner image is transferred by the secondary transfer roller 24. A transport conveyor 28B that transports the recording paper P toward 28A is provided. Note that the recording paper P is conveyed in the direction indicated by the arrow C in FIG. 1 by the recording paper supply device 26 and the fixing device 28.

  In the vicinity of the transfer belt 20 and at an intermediate position from the secondary transfer roller 24 to the primary transfer roller 22, the toner remaining on the transfer belt 20 after the toner image is transferred to the recording paper P by the secondary transfer roller 24. A toner removing device 30 for removing the toner is provided.

  A pre-cleaning corotron facing the photosensitive drum 12 is positioned slightly advanced in the rotational direction of the photosensitive drum 12 (arrow A direction) from the position where the primary transfer roller 22 and the photosensitive drum 12 sandwich the transfer belt 20. 32 is disposed. The pre-cleaning corotron 32 facilitates the removal of the transfer residual toner remaining on the photosensitive drum surface 12A. Above the pre-cleaning corotron 32, a cleaning device 34 for cleaning the surface 12A of the photosensitive drum 12 and removing the transfer residual toner is disposed.

  Details of the configuration of the cleaning device 34 are shown in FIG.

  As shown in FIG. 2, a seal member 36 is provided at the lower portion of the cleaning device 34 and substantially closes the gap between the photosensitive drum 12 and the cleaning device 34. As a result, the toner T in the cleaning device 34 is less likely to leak out of the cleaning device 34. The cleaning device 34 includes a brush roll 38 as a brush member in order to clean the toner T that is conveyed while remaining on the surface 12 </ b> A of the photosensitive drum 12.

  The brush roll 38 has a columnar shape as a whole, and is disposed close to the photosensitive drum 12 and in parallel with the photosensitive drum 12. A cylindrical brush shaft 38A is provided as an axis of the brush roll 38, and a large number of conductive fibers are radially planted on the peripheral surface of the brush shaft 38A via a conductive adhesive layer. The brush 38B is formed. A positive (eg, +260 V) DC voltage having the same polarity as the voltage applied in the toner image transfer process is applied to the brush 38B. Thereby, an electric field is formed between the surface 12A of the photosensitive drum 12 and the brush 38B, and the negatively charged toner T remaining on the surface 12A of the photosensitive drum 12 is electrostatically attracted to the brush 38B. For example, nylon or the like is used for the conductive fiber of the brush 38B. In the present embodiment, the negatively charged toner T is a polar toner with a large residual amount on the surface 12A of the photosensitive drum 12.

  The brush roll 38 is rotated in a clockwise direction (arrow 38C direction) in FIG. 2 by a motor (not shown), and scrapes the negatively charged toner T remaining on the photosensitive drum surface 12A by rubbing the photosensitive drum surface 12A. Can do. A detoning roll 42 as a collection roll is disposed at a position in contact with the brush roll 38. The detoning roll 42 is covered with a phenol resin, and is rotated counterclockwise in FIG. 2 (the direction of the arrow 42A) by a motor (not shown). A DC voltage larger than the voltage applied to the brush 38B (for example, + 660V) is applied to the detoning roll 42.

  A scraper 44 fixed to the lower edge 34A of the cleaning device 34 is disposed in the vicinity of the detoning roll 42, and the tip of the scraper 44 is in contact with the surface of the detoning roll 42 and is on the surface of the detoning roll 42. The negatively charged toner T is scraped off and removed. The scraper 44 is formed in a thin plate shape and is made of a metal such as stainless steel or steel.

  FIG. 3A shows a cross-sectional shape in the thickness direction (arrow W direction) of the tip end portion 44S of the scraper 44. The thickness D of the scraper 44 shown in FIG. 3A is 0.1 mm, and two continuous arcuate curved portions 44A and 44B are formed. Between the curved portions 44A and 44B is a mountain portion 44C, and edge portions 44D and 44E are formed on both sides of the scraper 44 in the thickness direction (arrow W direction). As shown in FIG. 3B, one of the edge portions 44D and 44E (44E in this embodiment) abuts against the surface of the detoning roll 42 and is used for scraping off the toner T.

  As shown in FIG. 2, a cleaning blade 46 is provided in the cleaning device 34. The cleaning blade 46 is in contact with the surface 12A of the photosensitive drum 12A on the downstream side of the brush roll 38 in the rotation direction (arrow A direction) of the photosensitive drum 12. It has been. The cleaning blade 46 is made of a plate-like rubber member such as urethane rubber, and a base end portion 46B is fixed to a substantially L-shaped support member 48. The support member 48 is fixed to an upper portion 34U of the cleaning device 34. Has been. The tip 46A of the cleaning blade 46 comes into contact with the surface 12A of the photosensitive drum, so that the toner T remaining on the surface 12A of the photosensitive drum is scraped off.

  A spiral auger 50 is provided below the cleaning device 34, and once the toner T scraped and removed by the scraper 44 and the cleaning blade 46 is received, the toner T is discharged from the cleaning device 34.

Next, a method for processing the tip portion 44S of the scraper 44 shown in FIG. 3A will be briefly described. The tip shape of the scraper 44 is formed by an etching process. First, as shown in FIG. 4, a photoresist pattern 54 is uniformly coated on both front and back surfaces of a thin metal plate 52 constituting the scraper 44 (see FIG. 3), and a mask pattern 56 having a mask portion 56A is formed. Laminate. Next, from the surface of the mask pattern 56 (in the direction of arrow R), exposure is performed on portions other than the mask portion 56A, and the photoresist layer 54 other than the mask portion 56A is cured. Then, after removing the uncured photoresist layer 54 located in the mask portion 56A, an etching process is performed from the surface side of the photoresist layer 54, so that the metal thin plate located in the mask portion 56A of the photoresist layer 54 is obtained. 52 is removed. FIG. 5A shows a state change when the metal thin plate 52 is subjected to the etching process. (The direction of etching is indicated by arrow E1.)
Here, when the etching process is performed even after the metal thin plate 52 is cut, as shown in FIG. 5B, an intermediate portion in the thickness direction (arrow W direction) and the thickness direction (arrow W direction). The erosion due to etching is slow on both sides, and the erosion progresses fast in the middle part between them. Here, the advancing direction of etching is indicated by an arrow E2. By performing such etching, the metal thin plate 52 is formed in the shape of the scraper tip 44S (see FIG. 3A) as indicated by the solid line.

  Next, the operation of the cleaning device 34 according to the above embodiment will be described.

  Transfer residual toner remaining on the surface 12 </ b> A of the photosensitive drum 12 after the transfer to the transfer belt 20 shown in FIG. 1 enters the position where the cleaning device 34 is disposed by the rotation of the photosensitive drum 12. As shown in FIG. 2, the transfer residual toner T is first disturbed by the brush 38 </ b> B of the brush roll 38.

  At this time, the negatively charged toner T is electrostatically attracted to the brush 38B because a positive voltage is applied to the brush 38B of the brush roll 38. Here, since a voltage higher than that of the brush roll 38 is applied to the detoning roll 42 adjacent to the brush roll 38, most of the negatively charged toner T electrostatically attracted to the brush 38B is detoned. Move to and adhere to the roll 42.

  The negatively charged toner T adhering to the detoning roll 42 is scraped off by the scraper 44 as shown in FIG. Here, the scraper 44 is composed of two arcuate curved portions 44A and 44B in which the cross-sectional shape in the thickness direction (arrow W direction) of the tip end portion 44S contacting the detoning roll 42 is continuous. The scraped piece K of the toner T that has been scraped off becomes smaller than the conventional one. For this reason, even if this small scraping piece K spills out of the cleaning device 34 shown in FIG. 2, the influence on the image quality is small, and image quality defects can be suppressed.

  The scraping pieces K (see FIG. 3B) are normally once received by the spiral auger 50 and then discharged from the cleaning device 34.

  Further, in this embodiment, after the toner T is removed by the brush roll 38, the remaining toner T is scraped off by the cleaning blade 46. Instead of the cleaning blade 46, a scraper 44 is arranged to dispose the surface of the photosensitive drum. The toner T on 12A may be scraped off.

  Further, in this embodiment, the toner remaining on the transfer belt 20 shown in FIG. 1 is removed by the toner removing device 30. The scraper 44 is provided in the toner removing device 30 and the toner on the transfer belt 20 is removed. May be scraped off.

  In the present embodiment, the case where the number of the bending portions 44A and 44B of the scraper 44 is two has been specifically described, but the number of the bending portions may be two or more. Further, in the present embodiment, the case where the curved portions 44A and 44B of the scraper 44 are continuously formed has been described. However, the curved portions are formed on both sides in the thickness direction, and the edge portions 44D and 44E are secured. In this case, the bending portion may be formed discontinuously. For example, a flat portion may be provided between the bending portion and the bending portion.

1 is a schematic configuration diagram of an image forming apparatus including a cleaning device of the present invention. It is a schematic block diagram which shows the structure of the cleaning apparatus of this invention. FIG. 3A is a cross-sectional view in the thickness direction of the scraper. (Only the tip portion is shown.) FIG. 3B is a schematic diagram showing a state in which the scraper scrapes off the toner. It is sectional drawing which shows the constituent material before the process of the scraper front-end | tip part. It is sectional drawing which shows the progress state of an etching. FIG. 5A shows a change in state until the metal thin plate is cut. FIG. 5B shows a change in state after the metal thin plate is cut.

Explanation of symbols

34 Cleaning device 42 Detoning roll (rotating body)
44 Scraper 44A Curved portion 44B Curved portion 44S Tip portion T Toner

Claims (1)

A cleaning device that applies a metal sheet scraper to the surface of a rotating body that holds toner and scrapes off the toner on the surface of the rotating body,
The scraper includes a curved portion having a plurality of arcuate cross-sectional shapes in a thickness direction of a tip portion that contacts the rotating body.

Images