JP2007065450A - Cleaning device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device that prevents a cleaning blade from turning upward, using a simple and inexpensive constitution. <P>SOLUTION: The cleaning device, having the cleaning blade pressed against an image carrier for removing untransferred toner remaining on the image carrier, is provided with a turn-over preventing member which is formed as a rigid body, positioned downstream from the cleaning blade in the rotating direction of the image carrier, arranged 1 to 2 mm apart from the cleaning blade, and is formed shorter than the edge of the cleaning blade. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions, and is a transfer residue remaining on the image carrier after being pressed against the image carrier. The present invention relates to a cleaning device that removes toner, and more particularly, to a technique for preventing a cleaning blade from turning over.

  A technique for removing residual transfer toner remaining on an image carrier of a photosensitive drum or an intermediate transfer belt with a cleaning blade has been conventionally known.

  While the cleaning blade is in pressure contact with the image carrier, the discharge product adheres to the surface of the image carrier due to the discharge phenomenon or the surface of the image carrier is damaged. The frictional force between the blade and the image carrier increases. Since the cleaning blade is formed of an elastic body such as urethane rubber, when the frictional force is increased, the edge of the cleaning blade is deformed and pulled to the downstream side in the rotation direction of the image carrier. This is called turning over.

  FIG. 4 is an enlarged view showing a state in which turning has occurred. 4 shows a state in which the cleaning blade 81 is in pressure contact with the image carrier 1, and the image carrier 1 rotates in the direction of the arrow. The cleaning blade 81 indicated by a two-dot chain line is in a normal state, and the cleaning blade 81 indicated by a solid line is in a state in which turning has occurred.

  Then, when the cleaning blade is deformed to some extent by turning, an operation to return to the original state is performed. When such a reciprocating operation is repeated, the edge of the cleaning blade is chipped, reversed, etc. As the service life is shortened, a cleaning defect occurs and an image defect occurs. Further, residual toner may be scattered in the apparatus or the image carrier may be wrinkled.

  In order to cope with such a problem, there is a cleaning blade having a two-layer structure including an edge layer in contact with an image carrier and a base layer bonded to a support member (see Patent Documents 1 and 2).

There is also a cleaning blade in which an elastic member is closely attached (see Patent Document 3).
JP 2002-214989 A JP 2002-214990 A Japanese Patent Laid-Open No. 2002-196641

  In the above-mentioned Patent Documents 1 and 2, since the edge layer and the base layer are those whose hardness and rebound resilience are regulated to predetermined values, and both must be bonded, it is compared with a conventional cleaning blade. Therefore, there is a problem that the manufacturing is troublesome and the cost becomes high.

  Further, in Patent Document 3, the vibration of the cleaning blade is absorbed by an elastic member for stabilization and does not prevent turning.

  The present invention has been made in view of such problems, and an object of the present invention is to propose a cleaning device that prevents the cleaning blade from being turned over with a simple and inexpensive configuration, and an image forming apparatus including the cleaning device.

  The above object is achieved by the following means.

  In a cleaning device having a cleaning blade that presses against an image carrier and removes transfer residual toner remaining on the image carrier, the cleaning device is formed on a rigid body, and is positioned on the downstream side in the rotation direction of the image carrier with respect to the cleaning blade, A cleaning device, wherein the cleaning blade is disposed at an interval of 1 mm or more and 2 mm or less with respect to the cleaning blade and is formed shorter than an edge of the cleaning blade.

  According to the present invention, even if the cleaning blade is pulled to the downstream side in the rotation direction of the image carrier due to the frictional force between the cleaning blade and the image carrier, it is prevented from being turned downstream with respect to the cleaning blade. Since the cleaning blade comes into contact with the member, no turning is generated. In this way, turning over can be prevented with a simple and inexpensive configuration. As a result, the life of the cleaning blade is prolonged, and good image formation can be maintained.

  Embodiments relating to the cleaning device of the present invention will be described.

  First, an image forming apparatus using a cleaning device according to the present invention will be described with reference to the basic configuration diagram of FIG.

  In FIG. 1, reference numeral 1 denotes a photosensitive drum as an image carrier. The photosensitive drum 1 is rotationally driven in a direction indicated by an arrow at a predetermined peripheral speed, and its surface is negatively charged by a charger 2 at a predetermined potential VH. Are uniformly charged.

  An exposure device 3 outputs a laser beam modulated in accordance with a time-series digital pixel signal of image information input from an image reading device (not shown), a computer, or the like. The uniformly charged surface of the photosensitive drum 1 is scanned and exposed by this laser beam. As a result, the absolute value of the potential of the exposed portion of the photosensitive drum 1 decreases to become the potential VL, and an electrostatic latent image is formed on the surface of the photosensitive drum 1.

  The developing device 4 includes a developing roller 4a that is rotationally driven. The developing roller 4a is disposed opposite to the photosensitive drum 1, and a thin layer of negatively charged toner is formed on the outer peripheral surface thereof. A developing bias voltage whose absolute value is smaller than the potential VH of the photosensitive drum 1 and larger than the potential VL is applied to the developing roller 4a, whereby the toner on the developing roller 4a becomes the potential of the photosensitive drum 1. Reversal development is performed only on the VL portion, and a toner image is formed.

  On the other hand, the recording paper P, which is a transfer material fed from a paper supply unit (not shown), passes through the registration rollers 9 and is synchronized with the photosensitive drum 1 and the charged transfer pole 5 at an appropriate timing synchronized with the rotation of the photosensitive drum 1. To the transfer area formed in The toner image on the photosensitive drum 1 is transferred to the recording paper P by the charged transfer pole 5 to which a transfer bias is applied.

  Reference numeral 6 denotes a fixing guide, and the recording paper P onto which the toner image has been transferred is conveyed to the fixing device 7 where the toner image transferred onto the recording paper P is fixed. The recording paper P that has passed through the fixing device 7 and has been fixed with the toner image is discharged onto a paper discharge tray (not shown).

  On the other hand, the photosensitive drum 1 from which the recording paper P has been separated is removed by the cleaning blade 81 of the cleaning device 8 to remove residues such as transfer residual toner adhering to the surface, and the cleaned photosensitive drum 1 is repeated. It is used for the next image formation.

  Note that in an image forming apparatus including, as an image carrier, a fixing belt that secondarily transfers an image primarily transferred from a plurality of photosensitive drums onto a recording sheet, the present invention is used to remove transfer residual toner remaining on the fixing belt. Alternatively, the cleaning device 8 may be used.

  In any case, the image forming apparatus provided with the cleaning device of the present invention may be a monochrome image forming apparatus or a color image forming apparatus.

  Next, an embodiment of the cleaning apparatus according to the present invention will be described with reference to FIG. FIG. 2 is a sectional view of the cleaning device 8.

  Reference numeral 80 denotes a casing, to which each member constituting the cleaning device 8 is mounted.

  A cleaning blade 81 is formed from an elastic body such as urethane rubber, and is fixed to the blade holder 82 with an adhesive or the like. The blade holder 82 is rotatably attached to a support shaft 83 provided in the casing 80.

  Reference numeral 84 denotes a tension spring that urges the blade holder 82 to rotate counterclockwise about the support shaft 83, and causes the edge 81 a of the cleaning blade 81 to move in a direction opposite to the rotation direction of the photosensitive drum 1 (counter direction). ) In a state of being in contact with the photosensitive drum 1.

  Reference numeral 85 denotes an auxiliary roller formed of urethane rubber or the like on the surface, and the photosensitive drum 1 is positioned upstream of the contact position between the edge 81a of the cleaning blade 81 and the photosensitive drum 1 in the rotational direction of the photosensitive drum 1. 1 abuts. The auxiliary roller 85 is configured to rotate in the forward direction with the photosensitive drum 1 by a rotating means (not shown), and its peripheral speed is faster than the peripheral speed of the photosensitive drum 1.

  Reference numeral 86 denotes a flicker made of a resin plate, a stainless steel plate or the like, and one end of the flicker is in contact with the auxiliary roller 85 at a position opposite to the contact position between the auxiliary roller 85 and the photosensitive drum 1.

  Reference numeral 87 denotes a seal plate fixed to the casing 80 and abuts against the photosensitive drum 1 to prevent the transfer residual toner from leaking.

  A screw 88 is provided at the bottom of the casing 80 and is rotated by a driving source (not shown).

  In the cleaning device 8 configured as described above, the transfer residual toner remaining on the photosensitive drum 1 is scraped off and removed by the cleaning blade 81 to clean the photosensitive drum 1. The removed transfer residual toner adheres to the auxiliary roller 85, is further scraped off by the flicker 86, and falls to the lower part of the casing 80. The fallen transfer residual toner is conveyed in the direction perpendicular to the paper surface by the rotation of the screw 88 and discharged out of the casing 80, and is collected in a waste toner collection box (not shown) and discarded, or is conveyed to the developing device 4 and reused. Or

  Here, while the cleaning blade 81 is in pressure contact with the photosensitive drum 1, discharge products adhere to the surface of the photosensitive drum 1 due to a discharge phenomenon, or the surface of the photosensitive drum 1 is damaged. As a result, the frictional force between the cleaning blade 81 and the photosensitive drum 1 increases. When the frictional force is increased, the edge 81a of the cleaning blade 81 formed of an elastic body such as urethane rubber is deformed and turns up. Then, when the cleaning blade 81 is deformed to some extent by turning, an operation of returning to the original state is performed, and when such a reciprocating operation is repeated, the edge 81a of the cleaning blade 81 is chipped or reversed, The life of the cleaning blade 81 is shortened, a cleaning defect occurs, and an image defect occurs.

  In order to solve such a problem, a turn-up preventing member 89 is fixed to the blade holder 82 by adhesion or the like on the downstream side in the rotation direction of the photosensitive drum 1 with respect to the cleaning blade 81.

  FIG. 3 shows an enlarged view of the turn-up preventing member 89.

  The turn-up preventing member 89 is formed in a rigid body with a metal plate such as stainless steel (for example, a plate thickness of 1 mm), and has a predetermined gap C with respect to the cleaning blade 81. Further, the position of the tip end portion of the turn-up preventing member 89 is shorter than the edge 81a of the cleaning blade 81 by a predetermined length L1. As a result, when the cleaning blade 81 starts to be deformed due to friction with the photosensitive drum 1, it comes into contact with the turn-up preventing member 89 and is prevented from further deforming, so that no turn-up occurs.

  The gap C is preferably 1 mm or more and 2 mm or less, and the length L1 is preferably 3 mm or more and 5 mm or less. If the gap C is less than 1 mm or the length L1 is less than 3 mm, the elasticity of the cleaning blade 81 is impaired and the cleaning performance deteriorates, and the gap C exceeds 2 mm or the length L exceeds 5 mm. If you do, you will not be able to expect the effect of turning over.

  The thickness D of the cleaning blade 81 is 1.8 mm or more and 2.5 mm or less, and the length of the cleaning blade 81 from the blade holder 82, that is, the free length L2 is 5 mm or more and 12 mm or less.

1 is a basic configuration diagram of an image forming apparatus. It is sectional drawing of a cleaning apparatus. It is an enlarged view of a turning prevention member. It is a figure which shows the state which turned over.

Explanation of symbols

1 Photosensitive drum 81 Cleaning blade 81a Edge 82 Blade holder 89 Turning-up prevention member

Claims (3)

In a cleaning apparatus having a cleaning blade that presses against an image carrier and removes transfer residual toner remaining on the image carrier,
It is formed on a rigid body, is located downstream of the cleaning blade in the rotation direction of the image carrier, and is disposed at an interval of 1 mm or more and 2 mm or less with respect to the cleaning blade, and is formed to be shorter than the edge of the cleaning blade to prevent curling. A cleaning device comprising a member. The cleaning apparatus according to claim 1, wherein the turn-up preventing member is formed to be shorter than the edge of the cleaning blade by a length of 3 mm or more and 5 mm or less. An image forming apparatus comprising the cleaning device according to claim 1.

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