JPH0131632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cleaning device using an elastic blade for removing toner remaining on the surface of a toner image carrier.

In transfer-type electrophotographic copying machines and electrostatic printing (hereinafter referred to as electrostatic recording devices), it is necessary to clean toner remaining on the surface of a photoreceptor or dielectric, that is, a toner image carrier.

In an electrostatic recording device using a photoreceptor with a smooth surface such as selenium, an organic photoconductor, or cadmium sulfide, or a dielectric material such as polycarbonate, an effective cleaning method is to use an elastic blade. Conventional blade cleaning devices include the two shown in Fig. 1 and Fig. 2.
There are two types. A plate-shaped elastic blade 2 supported by a holder 3 is in contact with a drum-shaped toner image carrier 1 that rotates in a clockwise direction using A as a contact point. Tangent line X-X at point A and holder 3
Among the angles formed with the axis YY, if the angle on the uncleaned portion 1a side is φ, it can be divided into two types: φ>π/2 and φ<π/2.

(1) φ>π/2 (Fig. 1) In this type, the blade is moved by the frictional force that acts between the toner image carrier and the blade as the toner image carrier moves. The blade is deflected and compressed toward the cleaning side, and the reaction force causes the edge portion of the blade to press against the surface of the toner image carrier with a large force. Therefore, the residual toner cleaning power is great, but the disadvantage is that excessive force is applied to the surface of the toner image carrier, which may damage the surface. Further, the frictional force acts as a force that compresses the blade in its longitudinal direction, and slight fluctuations in the frictional force appear as flapping of the blade.

(2) φ<π/2 (Fig. 2) Due to the frictional force between the blade and the surface of the toner image carrier, there is no strong reaction force from the blade, which causes problems like those in method (1). There are no points, but
On the other hand, the cleaning power is weak and cleaning defects tend to occur easily.

Furthermore, in this method, as φ is increased to approach π/2, the cleaning performance generally improves, and the phenomenon of toner filming, in which toner components adhere to the surface of the toner image carrier and form a film, also occurs. However, a bending moment acts on the blade and vibrations are likely to occur, making it difficult to uniformly contact the blade with the surface of the toner image carrier.

Further, in order to suppress the occurrence of the above-mentioned vibration, it is possible to reduce φ, but if it is made smaller, the cleaning force becomes weaker and toner filming is more likely to occur. Furthermore, foreign objects such as carriers are likely to be caught between the toner image carrier and the blade, causing scratches on the surface of the toner image carrier.

After studying the advantages and disadvantages of the above two types, the inventors of the present invention succeeded in eliminating defects and obtaining a stable cleaning device by providing a new blade shape.

That is, the present inventors previously filed Japanese Patent Application No. 56-11332.
In the specification of the above patent, a cleaning device as shown in FIG. 3 was proposed. The proposal is to use a plate-shaped elastic blade having a chevron-shaped protrusion near its tip in a cleaning device that removes toner remaining on the surface of a toner image carrier, and to align the ridgeline of the protrusion of the blade with the toner image carrier. It has a structure that presses against the surface, and the intersection angle φ between the blade holder and the surface of the toner image carrier is 0< on the uncleaned side.
The cleaning device is characterized in that φ<π/2.

The above-mentioned proposal for an improved blade improves many of the drawbacks of cleaning devices using conventional blades, but it has the drawback that the shape of the blade is somewhat complicated.

The present invention has been made with the aim of further developing the above-mentioned improved blade by fixing the blade member near the tip of the elastic plate, and further improving the function and simplifying the structure. In a cleaning device for removing toner remaining on the surface of a toner image carrier, an elastic blade member having at least one ridgeline is fixed near the tip of an elastic plate, and a holder for the elastic plate is fixed to the ridgeline portion of the blade member. The ridgeline portion on the side closer to is pressed against the image carrier, and the intersection angle φ between the tip of the elastic plate and the tangential plane of the image carrier at the pressure tangent line of the ridgeline portion is on the uncleaned side. This is achieved by a cleaning device characterized in that 30°≧φ≧−20°.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 4 shows a first embodiment of the present invention.

A blade member 6a having at least one edge 61a is fixed near the tip of an elastic plate 5a supported by the holder 4a, and the edge 61a on the side closer to the holder 4a is brought into pressure contact with the image carrier 1.

Edge 61a of blade member 6a and image carrier 1
and the direction ZZ of the tip of the elastic plate 5a
The intersecting angle φ with the uncleaned side is
It is set so that 30°≧φ≧−20°. This angular range was obtained through many experiments and was determined as a common condition for obtaining good results for each item such as cleaning effect, toner filming, and damage to the surface of the image carrier. It is something that

Here, the holder 4a is rotatable, and the edge 6
Pressure force at 1a is 10gr・wt/cm ~ 60gr・wt/cm
It has a mechanism to

The elastic plate 5a has an appropriate elastic modulus for uniformly pressing the blade member 6a against the image carrier 1, and is made of a metal plate such as phosphor bronze with a thickness of 0.1 mm to 0.5 mm, or a metal plate of 0.1 mm to 2 mm thick. Polyester sheets etc. are suitable. Other plastic materials such as polyester glass fiber reinforced plastic and polyamide,
Alternatively, elastic rubber materials such as polyurethane and nitrile rubber can also be used.

The material of the blade member 6a is synthetic rubber such as urethane, silicone, nitrile, neoprene, perferon, or natural rubber, and an elastic material is suitable.

In addition, in the embodiment shown in the fourth figure, the blade member 6
A has a symmetrical shape with edge parts on both sides, so that if the edge part on one side is damaged due to wear or dirt, it can be replaced to use the edge part on the opposite side. It is.

The fifth figure shows another embodiment of the present invention, in which the blade member 6b has a simple shape and is particularly easy to manufacture.

The present invention, which has been explained above using examples, has the following effects.

(1) Compared to the conventional method shown in FIG. 2, the toner filming phenomenon caused by toner being forced into the vicinity of the blade contact portion and rubbing against the image carrier is less likely to occur. In addition, the carrier etc. are less likely to be pinched, and the surface of the image carrier is not damaged thereby. Furthermore, the drag force from the blade when the residual toner tries to pass through the blade is generated partly by the deformation stress of the blade and the bending stress of the elastic plate, but mostly by the tensile stress of the elastic plate. This drag force is considerably larger than that of the method shown in the second figure, and therefore, the cleaning device of the present invention is extremely unlikely to leave any toner left unswept.

(2) In the method shown in the first diagram, there is a risk of damaging the surface of the image carrier due to excessive pressure applied as described above, but according to the cleaning device of the present invention, the elastic plate may be bent or the holder may be damaged. Since excessive contact force is not applied due to rotation, damage to the image carrier is unlikely to occur.

(3) In the cleaning device of the present invention, the blade member and the elastic plate do not need to be made of the same material, and the optimal material for each function can be selected, so that good effects can be obtained. You have a wider range of choices.

(4) In the cleaning device of the present invention, since the blade material has a relatively simple shape, the edge portion of the blade material that comes into pressure contact with the image carrier can be easily manufactured with high precision.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 show a conventional cleaning device, and FIG. 3 shows a cleaning device for which the present inventors previously applied for an invention. FIG. 4 and FIG. 5 each show an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Image carrier, 4... Holder, 5... Elastic plate, 6... Blade member, 61... Ridge line part (edge).

Claims (1)

[Claims] 1. In a cleaning device for removing toner remaining on the surface of a toner image carrier, an elastic blade member having at least one ridge line is fixed near the tip of an elastic plate, and the ridge line portion of the elastic plate is The ridgeline portion on the side closer to the holder is pressed against the image carrier, and the intersection angle φ between the tip of the elastic plate and the tangential plane of the image carrier at the pressure tangent line of the ridgeline portion is on the uncleaned side. A cleaning device characterized in that 30°≧φ≧−20°.