JPS6173180A - Cleaning device of copying machine - Google Patents

Abstract

PURPOSE:To improve a contact state to the surface of a photosensitive body of a cleaning blade by providing a supporting shaft which becomes a supporting point for supporting pivotally a blade assembly and welding by pressure the cleaning blade to the photosensitive body, on an area of the photosensitive body side with respect to a tangent of the photosensitive body in a contact of the cleaning blade and the photosensitive body. CONSTITUTION:A titled cleaning device is constituted so that the tip of a cleaning blade 8 is prevented from being damaged due to a flow of a photosensitive body surface 9a, etc. by utilizing a member fixed to a carriage 4, which is not shown in the figure, and bringing the carriage 4 to a reciprocating motion by a prescribed stroke in the axial direction of a photosensitive body 9. In this case, it is necessary that a supporting shaft 3 is placed at the downstream side in the advance direction of the photosensitive body 9 with respect to the cleaning blade 8. In this way, the force for welding by pressure the cleaning blade 8 and the photosensitive body 9 is stabilized, and even if the photosensitive body 9 becomes eccentric, the carriage rotates centering around the supporting shaft 3, the cleaning blade 8 follows it, and the photosensitive body 9 is welded by pressure stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device installed in a copying machine, and more particularly to a counterweight type blade cleaning device.

[Conventional technology]

BACKGROUND ART Conventionally, blade cleaning type cleaning devices have been widely used as cleaning devices for copying machines. The device is
It has been widely adopted because of its advantages such as small size, good cleaning efficiency, no noise, less dirt inside and outside the machine due to toner, and easy reuse of collected toner. There are a spring method, a counterweight method, and a method in which a cleaner body is attached as a pressure contact method for the cleaning blade, and among these methods, the counterweight method is common.

This counterweight cleaning device eliminates the need to adjust the blade pressure contact force because there is little variation in the blade pressure contact force (and there is no need for an adjustment mechanism. It has features such as being able to absorb vibrations and applying a constant pressing force even if the blade changes over time due to heat, ozone, etc.

[Problem that the invention seeks to solve]

However, in the above conventional structure, the position and angle of the cleaning blade relative to the photoconductor depend on the friction between the cleaning blade and the photoconductor, and for example, the amount of residual toner on the photoconductor surface becomes extremely large. When the amount decreases, or when the temperature is high and humidity is high, the frictional force increases and the contact angle of the blade increases. As a result, there has been a problem in that blade holdover and partial damage to the tip of the blade tend to occur.

The present invention improves the cleaning effect by improving the contact state of the cleaning blade with the photoconductor surface, and also prevents holdover of the cleaning blade due to changes in the amount of residual toner and the coefficient of friction on the photoconductor surface, etc. The object of the present invention is to provide a cleaning device for a copying machine that does not cause damage.

[Means and effects for solving the problem] The present invention provides a support shaft that pivots the blade assembly and serves as a fulcrum for pressing the cleaning blade against the photoreceptor, and the support shaft is connected to the tangent of the photoreceptor at the contact point between the cleaning plate and the photoreceptor. In contrast, it is provided in the area of the photoreceptor 1i11, thereby improving the contact state of the cleaning plate with the photoreceptor surface, improving the cleaning blade effect, and preventing holdover of the cleaning blade and damage to the tip of the blade. This is what I did.

(Example〕 Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

In Fig. 1, (A) is a cleaning device, in which a plaid Arasef (1) is disposed at the top, and a general feeding device (2) for conveying the collected residual toner is disposed at the bottom. There is.

(3) is a support shaft that allows the entire blade assembly (11) to rotate freely, and is provided in the copying machine body in an idling state.One end of the carriage (4) is attached to this support shaft (3). A counterweight (5) is installed vertically at the other end of the carriage (4).A blade holding member (6) is also installed in the middle of the carriage (4). A curved blade insertion groove (7) with an open bottom is formed in the blade holding member (6).
7), a thin plate-shaped cleaning blade (8) made of an elastic material is inserted. The tip of the cleaning blade (8), the beating blade edge (8a), is connected to the above-mentioned support shaft (3).
The photoconductor (9) rotates clockwise around a support shaft (0) parallel to the photoreceptor (9) at a predetermined angle.

This cleaning blade (8) touches the photoreceptor surface (9a).
The pressure required for cleaning is based on the moment of the counterweight 5) around the support shaft (3) in the blade assembly (1).

After the transfer, the residual toner (al) adhering to the photoconductor surface (9a) is scraped off by the blade edge (8a) that is in pressure contact with the photoconductor surface (9a), descends along the sealing member αω, and then The toner is sent downward by the toner transport body (11), and further transported to the side of the copying machine by the toner transport screw (12) for reuse.

Note that a member (not shown) fixed to the carriage (4) moves back and forth with a constant stroke, and the back light 14' is connected to the surface (9a).
The structure is such that the tip of the cleaning plate 1 (8) can be prevented from being scratched due to scratches or the like.

Note that the force with which the cleaning blade (8) presses against the photoreceptor (9) is stable, and even if the photoreceptor (9) is eccentric, the carriage (4) rotates around the spindle (3) and the cleaning blade ( 8) follows this and stably presses the photoreceptor (9). In this case, the support shaft (+3
) is placed between the photoreceptor (9) and the cleaning blade (8).
) shall be placed downstream in the direction of travel.

Next, the force relationship at the contact point (P) between the cleaning blade (8) and the photoreceptor (9) during cleaning will be described. In Figure 2, (0) is the support shaft of the photoreceptor (91), (P) is the cleaning plate (8) and the photoreceptor (9).
The contact point (Q) with the support shaft (3) is the fulcrum of the support shaft (3).

Figure 3 shows changes in the force relationship depending on the position of the fulcrum (Q).

In the figure, the fulcrums (Ql), (Q2), (Q3
) are points on the same circumference centered on the contact point (P), and the fulcrum (Ql) is the tangent to the contact point (I)). Moriyama (Q9) is the cleaning blade (8). The fulcrum (Qa), a point on the extension line of , is a point on the counterclockwise side with respect to the fulcrum (Q2).

The fulcrum of the cleaning blade (8) is (Q).

In order for the normal force (N) directed toward the center of the photoreceptor (9) acting as a cleaning force to be the same even in the cases of (Q2) and (Qa), the respective total forces (Tr), (T2), (Ta) becomes as shown in the figure. That is, in the case of the fulcrum (Ql), since the fulcrum (Ql) is on the tangent, N=TL. In the case of the fulcrums (Q2) and (Qa), in order to obtain the normal force (N) as the same component force, the total force (Tz
), (Ta) must be larger than (T).

Furthermore, the force relationship at the contact point (P) when the photoreceptor (9) rotates clockwise will be described.

When the photoreceptor (9) rotates, a frictional force (F) acts between the photoreceptor surface (9a) and the blade edge (8a).

This frictional force (F) is calculated as follows, where μ is the friction coefficient determined by the condition of the photoreceptor surface (9a) and the blade contact angle, etc.
F=μN, which changes depending on the friction state and the magnitude of the streamline force (N). Therefore, a tangential frictional force (F) acts on the photoreceptor (9), and a reaction force (1'') acts on the cleaning blade (8). Note that F' = F=
It becomes μN.

That is, when the photoreceptor (9) rotates, the cleaning blade (8) receives a total force (Ti) in the tangential direction.
The reaction force (F′) of the tangential component force (i) and the frictional force (F)
) is added. As shown in Figure 4, the reaction force (F') is similarly the force (F'a) along the cleaning blade (8).
and the force (F'b) directed toward the photoreceptor (9) perpendicular to this
).

Resultant force Fi +r2 of forces directed toward the photoreceptor (9)
b and Fi + [3b act as shown in FIG.

That is, when the photoreceptor (9) rotates clockwise, (Ql)
The cleaning blade (8) is pressed against the photoreceptor (9) by a counterweight (5) using the cleaning blade (8) as a rotational fulcrum.
) is subjected to a force directed toward the photoreceptor (9), which causes holdover in the counterclockwise direction due to Fi+fib. In this case, the position of the fulcrum (Q) is on the photoreceptor surface (9a)
As it moves counterclockwise from , the force (fib) increases, and eventually the holdover increases. However, this is the case when the normal force (al) is the same magnitude.

Here, the frictional force (F) is the absolute amount of residual toner (al) interposed between the photoreceptor (9) and the cleaning blade (8), and the residual toner (al) due to the charge held by the photoreceptor (
9) It changes depending on the electrostatic adhesion force between the friction coefficient (μ) and the environmental conditions, etc., but it is usually almost impossible to always control this to a certain value or less, and if the coefficient of friction (μ) becomes extremely large,
The cleaning blade (8) rotates as the photoreceptor (9) rotates.
The force Fb+fib that contributes to the holdover phenomenon over the entire surface from the blade edge (8a) side must be kept as small as possible by appropriately setting other controllable forces.

Therefore, the condition for minimizing Fb+fib is fib=O
, that is, the condition that the position of the fulcrum (Q) is the fulcrum (Ql), that is, (Ql) is the contact point of the cleaning blade (8) (
The same force relationship as above also holds true when the position is below the normal line fnl in P). In the case of the method of applying (;;i insect) to the cleaning blade (8) by applying the force (;; Remove the counterweight (5) from the blade cleaning device (A)
It would be impossible to arrange it between them.

Next, a case will be described in which the fulcrum (Q) is located in a region sandwiched between the tangent ([) at the contact point (P) and the photoreceptor (9).

In Figure 5, when the fulcrum of the support shaft (3) is (Qo) and the total force is (To), if the normal force (N) is set to the same value, the tangential component force (fo) teeth,
The force is in the opposite direction to the component forces ([2) and (f3), and as a result, the leaning blade (8) does not cause a holdover as described above. However, on the other hand, as the fulcrum (Qo) moves away from the fulcrum (Ql), it is necessary to apply a larger force to obtain the same value of normal force (N). The support shaft (3) is the fulcrum (Q2)
.

However, in the case of this fulcrum (Qo), no force that causes holdover is applied, so the cleaning blade (
The force applied to 8) will be used effectively.

Note that a spring may be provided in place of the counterweight (5).

〔Effect of the invention〕

As explained above, according to the present invention, the contact state between the cleaning blade and the photoreceptor surface is stabilized, the cleaning effect is stabilized, and the cleaning blade is protected.
This has the effect of preventing deterioration of copy quality.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the contact state between the cleaning blade and the photoreceptor, Fig. 3 is an explanatory diagram of the force relationship acting on the contact point, and Fig. 4 is an illustration of the cleaning An explanatory diagram of the force acting on the blade, Figure 5 shows the support shaft as the fulcrum (Qo
) is an explanatory diagram of the power relationship when cast. (1) Nibrate 7 no 7 no. 21: yIi feeder Cal: Support shaft (4
): Carriage nozzle (5): Counterweight (6) Ni-blade holding member (7) Ni-blade insertion slot (8): Cleaning blade (8a) Ni-blade edge (9): Photoreceptor αO1: Seal member (11)
) : l-ner transport body (12) : ) Chi propulsion screw (A) Niblade cleaning device (a): Residual toner (0) Forked shaft (p): Contact point Patent applicant Fuji Xerox Co., Ltd. Agent
Masu Tebori (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] 1. In a counterweight type blade cleaning device that removes residual toner on the surface of a photoconductor by pressing the surface of the photoconductor, the supporting shaft of the cleaning assembly is connected to the contact point between the cleaning blade and the photoconductor. A cleaning device for a copying machine, characterized in that it is disposed in an area closer to the photoreceptor than a tangent to the photoreceptor. 2. The cleaning device for a copying machine as set forth in claim 1, wherein the support shaft is provided on a tangent on the downstream side in the traveling direction of the photoreceptor with respect to the normal line at the contact point.