JP2007183420A - Toner scattering preventing device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a film seal from being deformed or turned up. <P>SOLUTION: A toner scattering preventing device 36 attached to the housing of a developing unit 14 or the like is provided with: a flexible film seal 41 arranged so that its surface near to a leading edge part comes in contact with the surface of a photoreceptor drum 11; and a holding member 43 supporting the trailing edge part of the film seal and turnably supported by a shaft pin 44 on the housing 31 at a position separate from the supporting position of the film seal. The holding member 43 is turned to an operating position PD on a near side by frictional force with the film seal 41 when the photoreceptor drum 11 normally rotates, and turned to a retreat position PT on a far side by the frictional force when the photoreceptor drum 11 reversely rotates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a toner scattering prevention device in an electrophotographic image forming apparatus, and a developing device and a cleaning device provided with the toner scattering prevention device.

  Conventionally, in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, a multi-function machine or a multi-function machine called MFP (Multi Function Peripherals), it is formed on a photosensitive drum as an image carrier. The electrostatic latent image is developed to form a toner image, the toner image is transferred onto an intermediate transfer member or a recording medium, and the transferred toner image is fixed to form an image.

  In such an image forming apparatus, a developing device for forming a toner image on the photosensitive drum and a cleaning device for removing the toner remaining on the photosensitive drum are provided.

  In such a developing device and a cleaning device, since the toner is directly handled, it is necessary to have a structure in which the toner does not scatter or leak around and does not solidify and stay.

  Conventionally, a film seal that seals the gap between the developing device and the surface of the photosensitive drum has been used as a toner scattering prevention device for the developing device (Patent Document 1). One end of the film seal is fixed to the housing of the developing device, and the other end contacts the surface of the photosensitive drum to seal the opening. Further, in order to shake off the toner adhering to the back surface of the film seal, the photosensitive drum is rotated reversely for each image forming job, thereby curving the film seal.

However, the reverse rotation of the photoconductor drum may cause the film seal to bend, which may cause the film seal to be lifted or turned over. Immediately after the reverse rotation of the photoconductor drum, the film seal may return to its original state. It has also been proposed to rotate forward.
JP 10-10864 A

  However, as in the prior art described above, there is a case where the film seal that has been lifted or turned up cannot be returned to its original state by simply rotating it forward immediately after reverse rotation of the photosensitive drum.

  That is, in order to stabilize the amount of film seal biting into the surface of the photosensitive drum and to prevent scratching of the photosensitive drum, the contact force of the film seal to the photosensitive drum may be lowered. At that time, if the angle of the film seal with the surface of the photosensitive drum is set to an acute angle, or if the material of the film seal is a hard material that easily undergoes plastic deformation or the film seal is thick, the photosensitive drum It can be considered that the film seal is broken or creep-deformed in the process of returning to the original state by forward rotation after deformation or turning by reverse rotation. In such a case, the original sealing function of the film seal cannot be performed.

  Also, even if it does not break or creep, once it is turned over, it will be difficult to return, the sealing function will be impaired, and the contact force to the surface of the photosensitive drum will increase, and image memory will be generated. It is also possible.

  The present invention has been made in view of the above problems, and even when the moving direction of an image carrier such as a photosensitive drum is switched between forward and reverse in order to shake off toner adhering to a film seal, An object of the present invention is to prevent the occurrence of seal deformation and curling and prevent stable toner scattering.

  A toner scattering prevention device according to the present invention is a toner scattering prevention device attached to a housing of a device provided opposite to an image carrier on which a toner image is formed, and a surface close to a tip is the image carrier. A flexible film seal disposed so as to be in contact with the surface of the body, and a rear end portion of the film seal are supported, and a shaft pin is rotated with respect to the housing at a position away from a support position of the film seal. A holding member that is movably supported, and the holding member is attached to the image carrier by a frictional force between the image carrier and the film seal when the image carrier is moved in a positive direction. It is configured to rotate to the operating position on the near side and to move to the retracted position on the far side from the image carrier by the friction force when the image carrier moves in the reverse direction. It is composed of.

  Preferably, a flexible cover member is provided between the holding member and the housing. The film seal is supported by the holding member via a seal holding member. The holding member is urged toward the operating position by an elastic member.

  The film seal is formed to have a thickness of 5 to 200 μm using, for example, any one of polyacetal, polyethylene, urethane, or polyester.

  According to the present invention, even when the moving direction of an image carrier such as a photosensitive drum is switched between forward and reverse in order to shake off toner adhering to the film seal, the film seal is prevented from being deformed or turned over. In addition, stable toner scattering can be prevented.

  1 is a front sectional view of the developing unit 14 according to the present invention, FIG. 2 is a front sectional view when the toner scattering prevention device 36 is in the operating position PD, and FIG. 3 is a diagram when the toner scattering prevention device 36 is in the retracted position PT. FIG.

  FIG. 1 shows a part of an electrophotographic image forming apparatus 1. That is, the image forming apparatus 1 is provided with a charging device, a transfer device, a cleaning device, and the like in addition to the photosensitive drum 11 and the developing unit 14 shown in the drawing. However, since the image forming apparatus 1 and the various devices constituting the image forming apparatus 1 are known except for portions related to the toner scattering prevention device described below, here, the developing unit 14, particularly the toner scattering thereof, is known. Only the prevention device 36 will be described.

  In FIG. 1, a developing unit 14 which is a developing device is provided to face the surface of the photoconductive drum 11, develops an electrostatic latent image formed on the photoconductive drum 11 with toner, and the surface of the photoconductive drum 11. A toner image is formed on the surface.

  The developing unit 14 includes a housing 31, screws 32 and 33, a roller 34, a developing sleeve 35, a toner scattering prevention device 36, a flexible cover 37, and the like.

  The housing 31 is a casing for constituting the developing unit 14 as one device, and is also a container for storing therein a two-component developer composed of a predetermined color toner TN and a magnetic carrier. The two-component developer may be described as “toner TN”. The housing 31 is provided with an opening KB at a portion facing the photoconductor drum 11, the developing sleeve 35 is disposed in the opening KB, and the toner scattering prevention device 36 covers the opening KB. Be placed.

  The screws 32 and 33 and the roller 34 agitate the toner TN by the rotation thereof, and send the toner TN toward the developing sleeve 35. The developing sleeve 35 is driven to rotate by a motor (not shown), and the toner TN attached to the surface thereof is sent to the photosensitive drum 11 to be attached to the surface of the photosensitive drum 11.

  The toner scattering prevention device 36 includes a film seal 41, a seal holding member 42, a holding member 43, a shaft pin 44, and the like.

  The film seal 41 is made of a synthetic resin such as polyacetal, polyethylene, urethane, or polyester so as to have a rectangular shape with a thickness of about 5 to 200 μm and has flexibility. The film seal 41 is disposed so that the surface (upper surface) near the tip thereof is in contact with the surface of the photosensitive drum 11.

  The seal holding member 42 is made of a synthetic resin, a metal material, or the like, and has a shape of an angle member having a length substantially the same as the width of the opening KB of the housing 31, that is, the axial length of the photosensitive drum 11. That is, the seal holding member 42 is L-shaped in a side view, and the rear end portion of the film seal 41 is attached to the attachment surface 42a which is one surface thereof. As a method of attaching the film seal 41 to the attachment surface 42a, for example, there are a method of attaching using an adhesive, a method of fixing by thermal welding, a method of pressing with another band material and screwing.

  In a state where the film seal 41 is attached to the attachment surface 42a of the seal holding member 42, the surface of the film seal 41 has a shape along the surface of the photosensitive drum 11, and the surface of the photosensitive drum 11 and the attachment surface 42a. The angle formed is an acute angle.

  The holding member 43 is made of a synthetic resin or a metal material, and is formed in a dogleg shape in a side view. A seal holding member 42 is attached to the upper end portion of the holding member 43 with screws or the like, thereby indirectly supporting the film seal 41. The holding member 43 is rotatably supported by the shaft pin 44 with respect to the housing 31 at a position away from the position where the film seal 41 is supported. Therefore, the entire holding member 43, the seal holding member 42, and the film seal 41 are attached to the housing 31 so as to be rotatable about the shaft pin 44.

  As the shaft pin 44, it is possible to apply a long rod shape, a short pin shape, a cylindrical protrusion from the housing 31 or the holding member 43, and other various shapes or structures. is there.

  The holding member 43 is in an operating position on the side close to the photosensitive drum 11 by the frictional force between the photosensitive drum 11 and the film seal 41 when the photosensitive drum 11 rotates in the positive direction (arrow M1 direction) (FIG. 1). 2 and the position shown in FIG. 2) When the photosensitive drum 11 is rotated in the reverse direction (arrow M2 direction), the retracted position (see FIG. 3) on the far side from the photosensitive drum 11 is also caused by the frictional force. The position shown) is adapted to rotate to PT.

  In addition, stoppers 45 and 46 that abut at each position and restrict further movement are provided so that the holding member 43 can rotate only between the retracted position PT and the operating position PD.

  A flexible cover 37 is attached between a surface different from the attachment surface 42a of the seal holding member 42 and the end surface of the housing 31, and a gap between them is covered. The flexible cover 37 is a film-like sheet made of synthetic resin or the like, and is flexible. Therefore, even if the holding member 43 rotates, the flexible cover 37 bends accordingly, and the holding member 43 There is no effect on the rotation.

  Now, depending on the rotation direction of the photoconductive drum 11, the direction of the frictional force between the photoconductive drum 11 and the film seal 41 is reversed, and the shape of the film seal 41 is deformed differently.

  That is, as shown in FIG. 2, when the photosensitive drum 11 is rotated forward for a normal image forming operation at the operation position PD of the holding member 43, that is, the toner scattering prevention device 36, the film seal 41 is tangentially moved. The frictional force F1 acts on the film, and the tangential component force F2 of the elastic force due to the deflection of the film seal 41 acts in the opposite direction. Usually, in the film seal 41, the frictional force F1 is sufficiently larger than the force F2, so that the film seal 41 is drawn in the traveling direction of the surface of the photosensitive drum 11.

  The frictional force F1 is determined by the coefficient of friction between the surface of the film seal 41 and the surface of the photosensitive drum 11, and the contact force F3 of the film seal 41 on the photosensitive drum 11. The coefficient of friction is determined by the material of the film seal 41, durability deterioration due to printing (image formation), dirt, and the like. The contact force F3 is determined by the material and size of the film seal 41, the amount of biting of the film seal 41 with respect to the photosensitive drum 11, and the contact angle of the film seal 41. The contact force F <b> 3 is a normal component of the elastic force due to the bending of the film seal 41 with respect to the photosensitive drum 11.

  When the photosensitive drum 11 rotates in the reverse direction, as shown in FIG. 3, the toner scattering prevention device 36 is in the retracted position PT.

  That is, in FIG. 3, due to the reverse rotation of the photosensitive drum 11, a frictional force F4 along the reverse rotation direction of the photosensitive drum 11 acts on the film seal 41, and the tangential component of the elastic force due to the deflection of the film seal 41 is exerted. Force F5 works. The friction force F4 and the force F5 both work in the direction of turning the film seal 41. However, since the film seal 41 is supported so as to be rotatable about the shaft pin 44, the film seal 41 is in contact with the photosensitive drum. 11 is rotated in a direction to follow the reverse rotation of 11 and moves to the retracted position PT, whereby the amount of biting of the film seal 41 into the photosensitive drum 11 is reduced. For this reason, the contact force F6 of the film seal 41 to the photosensitive drum 11 is reduced, thereby reducing the frictional force F4 and preventing the film seal 41 from being deformed or turned up.

  In addition, since the movement of the holding member 43 is regulated by the stopper 45, the film seal 41 is prevented from being retreated excessively and floating from the surface of the photosensitive drum 11 or toner leakage.

  Even when the photosensitive drum 11 finishes reverse rotation and the toner scattering prevention device 36 is left in the retracted position PT, the deformation of the film seal 41 is small, so that the film seal 41 creeps. There is little possibility of deformation or deterioration of the sealing function.

  Further, when the photosensitive drum 11 rotates in the forward direction after the reverse rotation, the frictional force F1 acts again in the forward rotation direction, and the film seal 41 moves so as to be pulled in that direction. In this case, since the holding member 43 is regulated by the stopper 46, the film seal 41 returns correctly to the operation position PD.

  As described above, according to the toner scattering prevention device 36 of the present embodiment, even when the moving direction of the photosensitive drum 11 is switched between forward and reverse in order to shake off the toner adhering to the film seal 41, the film seal 41. It is possible to prevent the toner from being scattered and to prevent the toner from scattering.

  Next, a modified example of the toner scattering prevention device 36 will be described.

  FIG. 4 is a front sectional view of the developing unit 14B in which the toner scattering prevention device 36B according to the modification is used, and FIG. 5 is a front sectional view when the toner scattering prevention device 36B is in the retracted position.

  In the toner scattering prevention device 36B shown in FIGS. 4 and 5, a winding spring 47 is mounted around the shaft pin 44. One end of the winding spring 47 is fixed to the housing 31 and the other end is fixed to the holding member 43, thereby urging the holding member 43 in the counterclockwise direction of the drawing. That is, the holding member 43 is urged by the winding spring 47 so as to return to the operating position PD.

  In FIG. 5, when the film seal 41 is retracted to the retracted position PT during the reverse rotation of the photosensitive drum 11, the winding spring 47 is pushed, so that the spring force F7 acts in a direction to return the holding member 43 to the operating position PD. In this case, when the photosensitive drum 11 changes from reverse rotation to normal rotation, the force for returning the holding member 43 is the resultant force of the frictional force F1 and the spring force F7. Can be returned to the operating position PD.

  FIG. 6 is a front sectional view of the developing unit 14C in which the toner scattering preventing device 36C according to the modification is used.

  In the toner scattering prevention device 36 </ b> C shown in FIG. 6, the holding member 43 extends below the shaft pin 44, and a weight 48 is attached to the lower end portion thereof. The weight 48 is for balancing the rotational moment about the entire shaft pin 44 of the toner scattering prevention device 36C including the film seal 41, the seal holding member 42, and the holding member 43. The presence of the weight 48 reduces the rotational moment of the toner scattering prevention device 36C.

  In the toner scattering prevention device 36C, the rotational moment is reduced and reduced, so that the retracting operation and the returning operation of the film seal 41 during reverse rotation and forward rotation of the photosensitive drum 11 can both be performed quickly and reliably. it can.

  In the toner scattering prevention device 36C shown in FIG. 6, the winding spring 47 shown in FIG. 5 may be used in combination. That is, a configuration in which the winding spring 47 and the weight 48 are combined may be employed.

  In the embodiment described above, an example in which the toner scattering prevention devices 36, 36B, and 36C are applied to the developing units 14, 14B, and 14C has been described. However, the toner scattering preventing devices 36, 36B, and 36C may be applied to devices other than the developing units. For example, as shown in FIG. 7, the toner scattering prevention device 36 </ b> D may be applied to the cleaning device 17.

  FIG. 7 is a front sectional view of the cleaning device 17 according to the present invention.

  In FIG. 7, a cleaning device 17 removes residual toner from the intermediate transfer belt 15. The cleaning device 17 includes a housing 51, a cleaning blade 52, a toner transport device 53, a toner scattering prevention device 36D, a flexible cover 37, and the like.

  The toner scattering prevention device 36D has the same structure as the toner scattering prevention device 36 described with reference to FIGS. The film seal 41 of the toner scattering prevention device 36D is in contact with the surface of the intermediate transfer belt 15, and sealing is performed at this portion to prevent the toner from scattering to the outside. Even when the intermediate transfer belt 15 performs forward / reverse rotation, the film seal 41 is prevented from being deformed or turned over, and toner scattering can be stably prevented.

  As described above, the toner scattering prevention device of the present invention can be applied to various image carriers such as the photosensitive drum 11 and the intermediate transfer belt 15.

  In the embodiment described above, a coil spring, a leaf spring, another spring, or another elastic member may be used instead of the winding spring 47. The structure, configuration, shape, dimensions, attachment method, material, number, etc., of the film seal 41, the seal holding member 42, or the holding member 43 can be variously changed in addition to those described above. The seal holding member 42 and the holding member 43 may be integrated. In addition, the structure, shape, dimensions, number, material, etc. of the whole or each part of the developing units 14, 14B, 14C, the cleaning device 17, or the image forming devices 1, 1B, 1C, 1D are appropriately determined in accordance with the spirit of the present invention. Can be changed.

FIG. 2 is a front sectional view of a developing unit according to the present invention. FIG. 4 is a front cross-sectional view when the toner scattering prevention device is in an operating position. FIG. 4 is a front cross-sectional view when the toner scattering prevention device is in a retracted position. FIG. 9 is a front sectional view of a developing unit in which a toner scattering prevention device according to a modification is used. FIG. 6 is a front cross-sectional view when a toner scattering prevention device of a modification is in a retracted position. FIG. 9 is a front sectional view of a developing unit in which a toner scattering prevention device according to a modification is used. It is front sectional drawing of the cleaning apparatus which concerns on this invention.

Explanation of symbols

1, 1B, 1C, 1D Image forming apparatus 11 Photosensitive drum (image carrier)
14, 14B, 14C Development unit (equipment)
17 Cleaning device (equipment)
31 Housing 36, 36B, 36C, 36D Toner scattering prevention device 37 Flexible cover (cover member)
41 Film seal 42 Seal holding member 43 Holding member 44 Shaft pin 47 Winding spring (elastic member)
51 Housing PD Operation position PT Retraction position

Claims (8)

A toner scattering prevention device attached to a housing of a device provided opposite to an image carrier on which a toner image is formed,
A flexible film seal disposed so that the surface close to the tip is in contact with the surface of the image carrier;
A holding member that supports a rear end portion of the film seal and is rotatably supported by a shaft pin with respect to the housing at a position away from a support position of the film seal,
The holding member is rotated to an operating position on the side closer to the image carrier by a frictional force between the image carrier and the film seal when the image carrier is moved in the positive direction. At the time of movement in the reverse direction of the body, the frictional force is configured to rotate to a retracted position on the side far from the image carrier.
An apparatus for preventing toner scattering in an image forming apparatus. A flexible cover member is provided between the holding member and the housing.
The toner scattering prevention device in the image forming apparatus according to claim 1. The film seal is supported by the holding member via a seal holding member.
The toner scattering prevention device in the image forming apparatus according to claim 1. The holding member is urged toward the operating position by an elastic member.
The toner scattering prevention device in the image forming apparatus according to claim 1. The film seal is made of polyacetal, polyethylene, urethane, or polyester, and has a thickness of 5 to 200 μm.
The toner scattering prevention device in the image forming apparatus according to claim 1.   A developing device provided with the scattering prevention device according to claim 1.   A cleaning device provided with the scattering prevention device according to claim 1.   An image forming apparatus provided with the scattering prevention device according to claim 1.