JPH0132055Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blade-type cleaning device for a photosensitive drum of an electrophotographic apparatus, particularly for a photosensitive drum having a seam portion extending in the axial direction.

2. Description of the Related Art As a photosensitive drum for an electrophotographic apparatus, a configuration in which a photosensitive plate with ends is mounted on the circumferential surface of a rotating drum is known. In such a structure, for example, both ends of the photosensitive plate are fixed in long grooves formed on the circumferential surface of the rotating drum, and these grooves are then closed by a holding member. may be installed in a state where it protrudes or is recessed from the surface position of the photoreceptor plate, and a step may be formed between it and the peripheral surface of the photoreceptor. On the other hand, the tip of a conventional cleaning blade extends along the axial direction of the drum and is always pressed against the circumferential surface of the drum, so when the drum rotates, the tip of the blade is exposed to the stepped portion. This collision would give an unexpected impact to the main body of the device, and could even cause the tip of the blade to be turned over or damaged.

The present invention was developed in view of this point, and even when a step is formed on the photosensitive drum,
It is an object of the present invention to provide a simple and convenient cleaning device that does not cause accidents such as impact to the device or damage to the blade.

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

In FIG. 1, reference numeral 1 denotes a rotary drum that rotates in the direction indicated by arrow A during operation, and a groove portion 2 extending in the axial direction is formed on the circumferential surface of the drum.
Both ends of a photosensitive plate 3, which is mounted in close contact with the circumferential surface of the drum 1, are fixed in predetermined positions within the groove portion 2, and a presser member 4 is then mounted so as to close the groove portion. Normally, the outer surface of the member 4 is fixed at a height that coincides with the outer circumferential surface of the photosensitive plate, but in the example shown in FIG. , indicates a case where a step occurs. In this specification, the term "joint part" refers to the attachment part of the end of the photosensitive plate, or in the case of a structure in which the photosensitive plate is glued onto a rotating drum, it refers to the overlapping part of the ends or the groove between the ends. .

The photosensitive plate has a known construction, and is sequentially subjected to the actions of an electrostatic latent image forming device, a developing device, and a transfer device as the drum rotates, and then cleaned by a cleaning device.

The cleaning device is generally indicated by the reference numeral 5 in the figure, and includes a blade device 10 for scraping off residual colored developer (hereinafter referred to as toner) on the photosensitive plate, and a blade device 10 located in front of the blade device with respect to the rotational direction of the drum. A recovery device 20 is provided to recover the scraped toner.

Blade apparatus 10 has a pair of spaced apart mounting hardware 11 each secured to a side plate of the xerographic apparatus. As shown in FIG. 2, the mounting bracket 11 has a dogleg shape, and has a screw hole 11a and a notch 11b formed at its upper end for fixing to the side plate of the electrophotographic device. , and has protruding portions 11c extending in directions facing each other at the other ends. The fittings 11 are connected to each other by a shaft 13 fixed to a bent portion thereof. On the other hand, the base body 12 is pivotally attached to the shaft 13. The base body 12 has a flat lower surface, and has a pair of side plates 12a and a rear plate 12c of the same shape projecting upward on the upper surface.
A notch portion 12d is formed in each of the side plates 12a, and the projecting portion 11c of the attachment fitting 11 is positioned in the notch portion, thereby limiting the range in which the base body 12 can pivot.

A blade reinforcing plate 14, a pressing member 15, and a support plate 16 are sequentially stacked and screwed to the lower surface of the base 12, and the blade 17 is
is disposed between the reinforcing plate 14 and the supporting plate 16 in a state where it is held between them. Reinforcement plate 14
has elasticity and is made of a thin plate of phosphor bronze in this example, and its tip portion is formed in a convex arc shape and is attached so as to protrude considerably from the tips of the base body 12 and the support body 16. The tip portion (pressing portion) of the pressing member 15 forms an arc concentric with the tip portion of the reinforcing plate 14, but is located inward therefrom as shown in FIG. On the other hand, the blade 17 is made of a rectangular parallelepiped thin plate made of an elastic material such as urethane rubber and is longer than the entire length of the photosensitive drum. It is curved and attached so that its tip forms an arc in the direction of the generatrix of the drum. The upper surface of the blade 17 is bonded to the lower surface of the reinforcing plate 14 with a suitable adhesive in order to maintain the above-mentioned curved state.
Further, the blade 17 has a size and shape such that its tip arc portion slightly protrudes from the tip of the reinforcing plate 14 when attached, and is attached so as to be in contact with at least the entire length of the photosensitive plate. . The blade device 10 having such a configuration has a base 1
Due to the action of a tension spring 18 provided between the rear plate 12c of 2 and a fixed part of the electrophotographic device, pressure is biased clockwise as viewed in FIG. It is pressed onto the circumferential surface of the drum and scrapes off any remaining toner on the circumferential surface of the drum.

According to the blade device according to the present invention described above,
Even when a step is formed on the photosensitive drum, residual toner on the photosensitive plate can be smoothly scraped off without causing an unexpected impact or damage to the blade.

Experimental example Using a photosensitive drum with a width of 345 mm, the outer surface of the presser plate was
It was set to be recessed by 0.3 mm from the circumferential surface of the photosensitive plate. The blade is 2mm thick and 350mm long with rubber hardness of 68 degrees.
A plate-shaped urethane rubber material is used, and a pressing member is used to adjust the tip to a radius of 480 with the center protruding the most.
It was curved to draw an arc of cm and was attached so as to protrude about 1 mm from the tip of the reinforcing plate. The blade was inclined at about 8 degrees with respect to the tangent to the drum, and the tip of the arc was positioned at the center of the drum, and was brought into pressure contact with the photosensitive drum for cleaning. As a result, it was found that the tip of the blade moved smoothly without colliding with the stepped portion with the presser plate, and the cleaning effect was also good.

The toner scraped off by the blade 17 is collected from the tip of the blade by a collection device 20. The recovery device 20 includes a roller 21 that rotates in the direction shown by arrow B and is placed close to the tip of the blade 17 and in light contact with the circumferential surface of the photosensitive drum.
and a scraping plate 22 made of an elastic material such as urethane rubber, the tip of which is pressed against the circumferential surface of the roller 21. The cylindrical roller 21 consists of an elastic roller 23 and a synthetic resin sleeve 24 covering the circumferential surface thereof. The sleeve 24 is formed of a material that has the property of being triboelectrically charged to a polarity opposite to that of the remaining toner when it comes into frictional contact with the scraping plate 22. Polyethylene is suitable when the residual toner is of positive polarity, and polyamide is suitable when the residual toner is of negative polarity. The remaining toner scraped off by the blade 17 is attracted onto the circumferential surface of the charged sleeve 24, and is carried away from the tip of the blade as the sleeve rotates. The remaining toner on the sleeve 24 is scraped off onto the tray 25 by the scraping plate 22.
The waste is collected by the screw conveyor 26 into a discharge container (not shown).

As described above, according to the present invention, smooth cleaning without impact can be performed with an extremely simple structure.

Note that in this specification, the term "arc" is not limited to circular arcs, but generally refers to gentle curves.

Further, in the above-mentioned example, the tip of the blade is formed into a convex arc shape, but the same effect can be obtained by forming it into a concave shape.

Furthermore, it is clear that the same effect can be achieved even if the blade is formed into an arc shape in advance.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of the cleaning device according to the present invention, FIG. 2 is an exploded perspective view of a portion of the device shown in FIG. 1, and FIG. 3 is a top view of the device shown in FIG. It is a diagram. 10... Blade device, 13... Reinforcement plate, 14
...Pushing member, 16...Blade.

Claims (1)

[Claims for Utility Model Registration] (1) A cleaning device for a photosensitive drum of an electrophotographic device, which blade is provided opposite to the rotating direction of the drum and has a tip having an arc shape in the generatrix direction of the drum. A cleaning device for an electrophotographic apparatus, comprising: a support device that supports the blade; and a pressure device that presses the tip of the blade against the circumferential surface of the photosensitive drum. (2) The cleaning device for an electrophotographic device according to item (1), wherein the blade is a rectangular parallelepiped and is attached to the support device in a curved manner. (3) In the cleaning device according to the above item (2), the support device includes a pressing member having an arc-shaped pressing portion that presses the rear end surface of the blade, and a pair of pressing members that sandwich the blade and the pressing member. 1. A cleaning device for an electrophotographic apparatus, comprising: a support member.