JPH0616218B2 - Blade cleaning device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade cleaning device for removing toner remaining on the surface of a photoconductor of an electronic copying machine.

As a means for removing toner remaining on the surface of a photoconductor of an electronic copying machine, a blade cleaning device for pressing a cleaning blade formed of a flexible member onto the surface of the photoconductor and scraping off the toner remaining on the surface. Is widely known.

For example, in Japanese Unexamined Patent Publication No. 47-45933, as shown in FIG. 2, a blade (1a) is swingably provided around a shaft (2a), and a photosensitive drum (3) of the blade (1a) is provided.
The angle (θ) of a) to the cleaned surface is 0 ° <
Blade with spring (4a) so that θ <90 °
A blade cleaning device of the type in which (1a) is pressed against the photosensitive drum (3a) with an appropriate pressing force is disclosed.

Problems to be Solved by the Invention In the blade cleaning device of the above method, the tangent line at the contact point where the blade (1a) contacts the photosensitive drum (3a) 2, the performance of the apparatus itself and its behavior greatly change depending on whether the shaft (2a) is on the side of the photoconductor drum (3a) or on the side opposite to the photoconductor drum (3a). Hereinafter, each case will be described with reference to FIGS. 3 and 4.

In Fig. 3, the axis (2a) is tangent It is shown above. That is, the axis (2a)
Is tangent It is located on the opposite side of the photoconductor drum (3a).
In the figure, if the center of the shaft (2a) is A and the contact point where the blade (1a) is in contact with the photosensitive drum (3a) is B, the blade (1a) is moved by the spring (4a).
When pressed against (3a), the line segment at contact point B
A pressure contact force F acting at right angles to ▼ and toward the photosensitive drum (3a) acts.

Under this pressure contact force F, the photosensitive drum (3a) moves in the direction of the arrow (C
Tangential line when rotated to W) A frictional force f acts in the direction.

This frictional force f is represented by the resultant force of the component fa in the direction of the line segment and the component fb in the direction perpendicular to the line segment.

Eventually, the force G acting on the contact point B in the direction perpendicular to the line segment direction is G = F + fb. This force G causes the blade (1a) to move the shaft (2a)
A rotational force is applied to the photosensitive drum (3a) in a direction of being pressed against the photosensitive drum (3a).

Therefore, the blade (1a) constantly acts on the photosensitive drum (3a) by the force G, so that the blade (1a) has good cleaning performance.

However, in the above structure, when the toner is left for a long time in a state where the toner is present between the photoconductor drum (3a) and the blade (1a), the toner is fixed to the photoconductor drum (3a), which causes frictional force. f may increase. In such a case, the component fb naturally increases, and the force G acting on the contact B becomes abnormally large, and the blade (1
It may lead to significant wear, biting, and even self-destruction in a).

On the other hand, in FIG. 4, the axis (2a) is tangential. Below, i.e. tangent On the other hand, the case where it is on the same side as the photoconductor drum (3a) is shown. In this case, the line segment ▼ that connects the center A of the shaft (2a) and the contact point B is the tangent line. Will be below.

Even in this state, the tangent line The component force of the frictional force f ′ acting in the direction is represented by the resultant force of the component f′a in the direction of the line segment ∘ and the component f′b in the direction perpendicular to the direction of the line segment ∘. However, in this case, the acting direction of the component f′b and the acting direction of the pressure contact force F are
Since the directions are opposite to each other by 180 °, the force G ′ acting on the contact point B in the direction perpendicular to the line segment direction is G ′ = F−f′b. This force G causes the blade (1a) to move the shaft (2a)
A rotational force is applied to the photosensitive drum (3a) in a direction of being pressed against the photosensitive drum (3a).

Therefore, when the frictional force f'of the blade (1a) is increased due to the above-mentioned cause, the component f'b acts to reduce the pressure contact force G ', so that the blade (1a) is significantly worn, dented, It does not cause destruction.

On the other hand, since the component f'b of the frictional force f'acts so as to constantly reduce the pressure contact force G ', the cleaning performance is inferior to that shown in FIG.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a blade cleaning device that has both good cleaning performance and safety in the event of an abnormality, and that has a very simple configuration.

Means for Solving the Problems In a cleaning device according to the present invention, a cleaning blade swingably provided around a support shaft makes an acute angle with the cleaned surface of the photoconductor to press it against the photoconductor surface. In the blade cleaning apparatus, the tip of the cleaning blade is on the same side as the photoconductor with respect to the tangent line of the photoconductor at the contact point where the contact is made with the photoconductor surface, Includes guide means for guiding the movement of the support shaft to a second position on the opposite side, and biasing means for biasing the support shaft along the guide means toward the second position. It is characterized by that.

Operation In the above-mentioned configuration, in a normal operating state, the support shaft of the cleaning blade is located at the second position along the guide means by the biasing means, and has a good cleaning performance with a strong pressure contact force. Also, if the frictional force between the cleaning blade and the photoconductor becomes abnormally large for some reason,
The support shaft moves toward the first position along the guide means against the biasing force of the biasing means, and acts so as to weaken the pressure contact force of the cleaning blade.

Embodiment An embodiment of the blade cleaning device according to the present invention will be described below with reference to FIG.

In the figure, (1) is a cleaning blade made of a flexible material, which is attached to the attachment member (6) via an elastic thin plate (5). The mounting member (6) is fixed to the support shaft (2), and the mounting member (6), the elastic thin plate (5) and the cleaning blade (1)
Are integrally swingable around the support shaft (2). A first spring (4) is provided at one end of the attachment member (6) for applying a counterclockwise rotational biasing force to the support shaft (2). Due to this biasing force, the cleaning blade
(1) is pressed against the photosensitive drum (3) at a contact point (C) so as to form an acute angle with the cleaned surface of the photosensitive drum (3).

On the other hand, the support shaft (2) is fitted in guide grooves (8) formed in side plates (7) (only one is shown) provided on both sides of the photoconductor drum (3). . The guide groove (8) has a first
As shown in Fig. (A), the tangent line passing through the contact C where the cleaning blade (1) is pressed against the photosensitive drum (3). With respect to the support shaft (2), the center (A) of the support shaft (2) is located above the support shaft (2), as shown in FIG. 1 (b). It is formed so as to guide the shaft (2). Further, the center (A) of the support shaft (2) is tangential when fitted in the guide groove (8). The second spring (9) is connected so as to be displaced upward.

In the above structure, as shown in FIG. 1 (a), the spindle (2) is normally tangent to the center (A) by the second spring (9). The cleaning blade (1) is positioned above the contact point (1), and a strong pressure contact force is applied to the contact (C) to obtain good cleaning performance.

On the other hand, when the frictional force f of the cleaning blade (1) at the contact point (C) increases due to the adhesion of toner, etc.,
Due to this increased frictional force f, the support shaft (2) resists the biasing force of the second spring (9) along the guide groove (8), and its center (A) is tangential. It moves in the direction of being positioned below and becomes the state shown in FIG. 1 (b). Along with this movement, the pressure contact force of the cleaning blade (1) at the contact point (C) decreases.

EFFECTS OF THE INVENTION As is clear from the above description, according to the blade cleaning device of the present invention, in the normal operating state,
The cleaning blade can be pressed against the photosensitive drum with a strong force, and it has good cleaning properties,
In an abnormal operating state in which the frictional force between the cleaning blade and the photoconductor has increased, it acts to weaken the pressure contact force of the cleaning blade, so it is necessary to prevent the cleaning blade from being significantly worn, dented, or self-destructed. You can

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 to 4 are diagrams for explaining a conventional technique. 1 ... Cleaning blade, 2 ... Spindle, 3 ... Photoconductor drum, 4 ... First spring, 8 ... Guide groove, 9
...... Second spring.

Claims (1)

[Claims] 1. A blade cleaning device in which a cleaning blade, which is swingably provided around a support shaft, is in pressure contact with the surface of the photoconductor at an acute angle with the cleaned surface of the photoconductor, and the tip of the cleaning blade is From a first position on the same side of the photoconductor to the tangent line of the photoconductor at the contact point pressed against the photoconductor surface to a second position on the opposite side of the photoconductor to the tangent line, A blade cleaning device comprising: guide means for guiding the movement of the support shaft; and urging means for urging the support shaft in the direction of the second position along the guide means.