JPH0142111Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a cleaning device for removing residual toner on the surface of a toner image carrier in an electrostatic recording device such as an electrophotographic copying machine. In particular, the present invention relates to an improvement in a trail-type blade cleaning device that includes a blade that intersects the surface of a toner image carrier at an acute angle and is in pressure contact with the surface of the toner image carrier.

2. Description of the Related Art As a cleaning device for an electrostatic recording device such as an electrophotographic copying machine, a trail-type blade cleaning device in which a blade is provided so as to intersect at an acute angle and come into pressure contact with the surface of a toner image carrier is widely used.

Trail-type blade cleaning devices tend to: ○ tend to form a toner film called a toner film on the surface of the toner image carrier; ○ fine, needle-like toner stickiness called black spots occur on the surface of the rotary image carrier under high temperature and high humidity. ○Fine mist-like black spots called black haze, which look like scattered toner, are likely to occur on the surface of the toner image carrier at low temperatures and low humidity. ○Contact with the edge of the blade when the nitoner image carrier is stationary. Horizontal line-shaped toner agglomeration areas that occur in areas tend to pass through the contact area with the edge of the blade, resulting in toner aggregation areas called horizontal streaks, etc., which tend to cause cleaning failures that adversely affect the quality of recorded images. There is a drawback.

Conventionally, in order to eliminate each of the above-mentioned cleaning defects, the contact angle or pressure contact force of the blade with respect to the surface of the toner image carrier has been adjusted.
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For example, the phenomenon of ○A can be achieved by increasing the pressure of the blade against the surface of the toner image carrier.
Its occurrence can be prevented. However, the blade is greatly deformed, and the frictional force generated at the contact portion of the blade increases. As a result, fine vibrations occur at the tip of the blade, and depending on environmental conditions such as temperature and humidity, black spots, black mist, etc. are likely to occur. That is, by preventing the occurrence of the phenomenon ○B, the occurrence of the phenomena ○B and ○C will be promoted. In addition, the phenomenon described in ○2 is caused by the blade being dragged when the toner image carrier starts up and the contact angle becoming smaller, and the pressing force of the blade becoming weaker as a result. This occurs when toner that has aggregated in a horizontal line passes through the contact area with the edge of the blade, but it can be prevented by increasing the contact angle or releasing the pressure contact force. Occurrence can be prevented.
However, it is necessary to maintain the angle of the blade stably and to increase the accuracy of the blade.

Furthermore, although the present applicant has already filed an application as Utility Model Application No. 58-60158, in a trail-type blade cleaning device, a part of the tip of the blade on the side opposite to the side that contacts the toner image carrier is removed. A trail that suppresses vibration of the blade by pressing with a pressing member made of an elastic material, eliminates various harmful effects caused by vibration, and provides stable and good cleaning performance. A type of blade cleaning device has been developed.

That is, in FIG. 9, 1 is a toner image carrier rotating in the direction of the arrow. 3 is a blade member,
A blade 31 provided so as to intersect at an acute angle φ with the tangential plane XX on the edge A that contacts the toner image carrier 1, an elastic pressing member 32 that presses the tip of the blade 31, a base of the blade 31, and an elastic The blade holder 33 holds the substrate portion of the pressing member 32. The elastic pressing member 32 is made of an elastic body, and has a tip 32a made of an aluminum block and a rear end attached to the blade holder 33 with a mounting member 34 such as a screw. is provided so that it can be pressed and supported on the side opposite to the elastic pressing member 32 so as not to curve into a convex shape. Reference numeral 4 denotes a support member, which includes a pivot 42 provided on both side plates (not shown) of the frame of the cleaning device, a crank-shaped support plate 41 supported by the pivot 42, and a support member 4 that rotates the support plate 41 clockwise. The blade member 3 is provided so that both ends of the blade member 3 are supported by support plates 41.

The blade cleaning device shown in FIG. 9 is constructed as described above, and when the toner image carrier 1 starts rotating in the direction of the arrow, the frictional force generated between the edge A of the blade 31 and the toner image carrier 1 As a result, the edge A of the blade 31 is dragged in the rotational direction of the toner image carrier 1, and the blade 31 is moved toward the blade holder 3.
3 and the support plate 41, but the rotation is restricted by the action of the tension spring 43. That is, the tip of the blade 31 is pressed against the toner image carrier 1 and tends to curve convexly in the direction of the upstream side 1a of the toner image carrier 1. However, since the tip of the blade 31 is pressed and supported by the tip 32a of the elastic pressing member 32, a reaction force by the elastic pressing member 32 acts against the force acting to curve the blade 31. Therefore, the shape before pressure welding can be almost maintained.

Therefore, at the time of startup, the contact angle between the blade 31 and the toner image carrier 1 does not become small, and the tip thereof does not rise, so that toner filming phenomenon or horizontal streaks hardly occur. do not have.

However, there are problems in that black haze occurs and the surface of the toner image carrier, especially when a resin is used as the photoconductive photoreceptor, becomes more abraded. The reason for this is thought to be that the tip of the blade 31 is pressed by the pressing member 32 having a tip 32a made of an aluminum block or the like. For example, when a variable load is applied to the blade 31 due to eccentricity of the toner image carrier 1, etc., it is difficult for the tip of the blade 31 to quickly absorb the load applied from the toner image carrier 1 or the temporal change in the load. This is considered to be because the edge A of the blade 31 is crushed or the tip of the blade 31 vibrates. Note that these phenomena can be observed using a stereomicroscope.

Purpose of the invention In view of the above-mentioned problems of the conventional ones, the present invention
By preventing excessive force from acting on the edge of the blade, it suppresses the occurrence of thin vibrations, prevents the occurrence of black spots, black haze, etc., and greatly stabilizes the contact angle of the blade. By suppressing the transient deviation of the blade edge at startup, it prevents the generation of horizontal streaks, and improves the effectiveness of the blade edge, thereby preventing the occurrence of toner filming and reducing environmental conditions. Alternatively, there is provided a trail-type blade cleaning device that can prevent deterioration in cleaning performance due to changes in the elastic modulus of the blade due to factors over time, and can reduce the degree of damage to a toner image carrier that is scraped off by the blade. The purpose is to

Structure of the Invention In order to achieve the above object, the present invention provides a trail-type blade cleaning device in which the tip of the blade is elastically pressed so that the blade curves concavely toward the surface that contacts the toner image bearing surface. In particular, it is possible to quickly absorb the frictional force received from the toner image carrier and fluctuations in the frictional force, and to set a large and stable contact angle with the toner image carrier. This is a trail-type blade cleaning device.

That is, the configuration of the present invention is such that in a trail-type blade cleaning device that includes a blade that is pressed into contact with the toner image carrier so as to intersect with the upstream surface of the toner image carrier at an acute angle, the tip of the blade is attached to the toner image carrier. This is a trail type blade cleaning device characterized by comprising an elastic pressing member that presses the blade upstream and curves the blade so as to be concave upstream of the toner image carrier.

(Example) The present invention will be explained in detail by way of examples.

FIG. 1 is a cross-sectional view schematically showing a trail type blade cleaning device according to an embodiment. FIG. 2 is a side view of the blade portion in FIG. 1. FIG. 3 is an explanatory diagram of the relative arrangement of the blade portion in FIG. 1 with respect to the toner image carrier. 4 to 6 are side views of modified examples of the blade portion. FIG. 7 is a side view of the blade portion in the experimental example. Figure 8 shows the 7th
It is a perspective view of the press member in a figure.

In FIG. 1, reference numeral 1 denotes a photosensitive drum which is a toner image bearing member and is rotated in the direction of the arrow. 2 is the frame of the blade cleaning device;
It is provided so as to be swingable by a pivot portion 21.
Further, the photosensitive drum 1 is pressed by a pressing means (not shown).
It is pressed in the direction and is stopped and positioned by the stopper 23. 3 is the blade part, blade 3
1, an elastic pressing member 32, and a blade holder 33 for holding them, and is attached to the frame 2 by a fixing member 22.

As shown in FIG. 2, the pressing member 32 is made of a flexible plate material such as a phosphor bronze plate material, and consists of a flat plate-shaped base portion 32b and an L-shaped tip portion 32a. The elastic pressing member 32 is attached to the blade holder 33 with its base plate 32b overlapping the base of the blade 31 so that its tip 32a presses the tip of the blade 31. Therefore, the cross-sectional center line of the blade 31 is set in a curved shape as shown by the dotted line. Further, as shown in FIG. 3, the blade 31 is configured such that the contact angle φ between the upstream surface of the photoreceptor drum 1 and the surface including the edge A of the blade 31 that contacts the photoreceptor drum 1 is an acute angle. It is located in

Since this embodiment is configured as described above, its functions and effects are as follows.

During a copying operation, the photosensitive drum 1 rotates in the direction of the arrow, and after a recorded image is transferred at a transfer section (not shown), toner of the toner image that was not used for transfer remains on the photosensitive drum 1. Once the residual toner reaches the blade portion 3 of the blade cleaning device, it is removed by the edge A of the blade 31.

When the photoreceptor drum 1 is started, a force is applied to the edge A of the blade 31 to move it downstream of the photoreceptor drum 1 due to the frictional force generated between the blade 31 and the photoreceptor drum 1, and the elastic pressing member 32 is moved. It is moved against the pressing force. As a result, the contact angle φ between the blade 31 and the photoreceptor drum 1 is reduced. However, since the blade 31 is curved by the elastic pressing member 32 so as to be concave toward the upstream side of the photoreceptor drum 1, the contact angle of the blade 31 with respect to the photoreceptor drum 1 is maintained large. Therefore,
Even if the edge A of the blade 31 moves during startup and the contact angle is reduced, a sufficiently large contact angle can still be maintained.

As described above, since the contact angle is maintained sufficiently large even when the photosensitive drum 1 is started, the horizontal linear toner that aggregates along the edge A of the blade 31 passes through the edge A of the blade 31 when the photosensitive drum 1 is stopped. It is removed without causing any horizontal streaks.

Further, since the blade 31 is curved, the contact angle φ between the blade 31 and the photosensitive drum 1 is set to be large, and the effectiveness of the edge A of the blade 31 is improved. As a result, toner filming phenomenon is less likely to occur.

On the other hand, since the contact angle is set large, the bending moment acting on the blade 1 as a component of the frictional force generated between the blade 31 and the photoreceptor drum 1 becomes large. Since the blade 31 is held in a curved shape by the member 32, the edge A of the blade 31 does not lift up and is always in contact with the surface of the photoreceptor drum 1. In other words, the edge A of the blade 31 is maintained in sliding contact with the surface of the photoreceptor drum 1 without generating minute vibrations between the blade 31 and the surface of the photoreceptor drum 1. Therefore, cleaning defects such as black stain and black haze rarely occur on the surface of the photoreceptor drum 1.

In addition, since the tip of the blade 31 is elastically pressed, it easily follows unevenness in the flatness of the photoreceptor drum 1, and no excessive force is applied, so that the force that rubs the surface of the photoreceptor drum 1 is reduced. was not excessive, and the amount of the surface scraped off by the blade 31 was significantly reduced compared to the conventional one shown in FIG.

Furthermore, since the blade 31 is attached to the blade holder 33 so as to overlap the elastic pressing member 32, even if the elastic modulus of the blade 31 changes due to environmental conditions or factors over time, the elastic pressing member 32
Due to its elasticity, it is always held in pressure contact with the photoreceptor drum 1 in a stable state.

The elastic pressing member 32 in this embodiment has a flat base plate portion 32b and an L-shaped tip portion 32a formed of a single flexible plate.
As shown in FIGS. 4 to 6, it may be formed by attaching another member to the lower surface of the tip of a single flat flexible plate. For example, FIG. 4 shows a metal plate with a rectangular cross section attached to the tip 32a, FIG. 5 shows a case with a rubber material such as polyurethane rubber or neoprene rubber attached, and The figure also shows the wires attached.

EXPERIMENTAL EXAMPLE The effects of the above embodiments will be explained by means of preferred experimental examples.

The apparatus used in this experimental example is the one shown in FIG. 1 incorporating the blade members shown in FIGS. 7 and 8.

The setting conditions for each member are as follows.

The blade 31 has a thickness of 5 mm (4 to 6 mm) and a width of 304 mm.
mm, free length 16mm (12~20mm), hardness 70 degrees (60~80
Made of polyurethane rubber. Note that the values in parentheses indicate preferred ranges.

The elastic pressing member 32 is made of a phosphor bronze plate with an integrally formed L-shaped tip as shown in FIG.
W304mm, length L40mm, tip length 3mm.

The blade holder 33 is a drawn aluminum material.

By overlapping the blade 31 and the elastic pressing plate 32 and attaching them to the blade holder 33 as shown in FIG. 8, the blade 31 was held in a curved shape with its cross-sectional center line indicated by the dotted line.

When the blade member 3 shown in FIG. 8 is assembled into FIG. 1, the contact angle φ between the blade 31 and the photoreceptor drum 1 is 70° (65 to 85°), and the contact force of edge A of the blade 31 is 4.0 g. /mm ² (3.5 to 6g/mm ² ). In addition, the value in parentheses indicates a preferable range.

The photosensitive drum 1 is made of OPC.

The results of repeating 20,000 copies under the above setting conditions are as follows.

Defects caused by poor cleaning such as horizontal streaks, black haze, and toner filming hardly occurred.

In addition, black spots do not occur even under high temperature and high humidity conditions.
Further, no black mist occurred even under low temperature and low humidity conditions. In other words, environmental resistance has been significantly improved.

Furthermore, regarding the wear of the OPC on the photosensitive drum by the blade, the thickness of the OPC was initially 15μ, but after 20,000 copies, it became 11μ, and after 20,000 copies, abrasion of 4μ occurred. Since the conventional one shown in FIG. 9 wears out by 5 microns after 10,000 copies, the amount of wear of the one of this experimental example was significantly reduced compared to the conventional one.

As can be seen from the results of the above experiments, by forcibly bending the blade using an elastic pressing member, it is possible to set a large contact angle of the blade, and to reduce the frictional force between the blade and the photoreceptor drum. It has become possible to quickly absorb the underlying load and fluctuations in that load. As a result, stress no longer accumulates at the tip of the blade, resulting in less vibration.

In addition, even if the contact angle is set large, the edge of the blade does not lift up and vibration does not occur at the tip of the blade, so the pressure force of the blade against the photoreceptor drum can be reduced, and the contact angle between the blade and the photoreceptor drum can be reduced. The wear of the OPC on the drum has also been reduced.

Effects of the invention In conventional trail-type blade cleaning devices, the tip of the blade is pressed and supported by an aluminum block or the like to prevent it from moving against the frictional force with the toner image carrier. Although the contact angle does not change and horizontal streaks can be prevented from occurring, on the other hand, the tip of the blade may vibrate and cause black mist, or the blade may apply a strong force to the toner image carrier and the toner image carrier may be scraped off. This caused the problem of

The present invention makes it possible to set a large contact angle of the blade by pressing the tip of the blade toward the upstream side of the toner image carrier and curving the blade in a concave shape toward the upstream side. It has become possible to quickly absorb the load based on the frictional force between the toner image carrier and the toner image carrier, and the fluctuations in the load.
As a result, even when starting up the toner image carrier,
The contact angle of the blade is kept sufficiently large, and stress does not accumulate on the tip of the blade, so there is almost no vibration, and even if the contact angle of the blade is increased, vibration does not occur at the tip of the blade. Therefore, the pressing force of the blade against the photoreceptor drum can be reduced. Therefore, cleaning defects such as horizontal streaks, black haze, black spots, and toner filming, which have been problems in the past, are less likely to occur, and the amount of wear on the toner image carrier is significantly reduced. Furthermore, by attaching the elastic pressing member to the blade holder so as to overlap the blade, a stable blade cleaning device can be obtained that is not affected by blade deterioration due to environmental conditions or factors over time. .

As described above, the present invention has been able to provide the above-mentioned trail type cleaning blade device which has a simple structure and excellent durability.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, and FIG.
The figure is a side view of the main part of Fig. 1, Fig. 3 is an explanatory diagram of the main part of Fig. 1, Figs. 4 to 6 are modifications of the main part of Fig. 1, and Figs. FIG. 8 is an explanatory diagram of main parts in an experimental example, and FIG. 9 is a schematic sectional view of a conventional example. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Frame of blade cleaning device, 3... Blade member, 31...
Blade, 32... Elastic pressing member, 33... Blade holder, A... Edge of blade, φ... Contact angle of blade 31 with respect to photoreceptor drum 1.

Claims (1)

[Claims for Utility Model Registration] (1) In a trail-type blade cleaning device that is equipped with a blade that is pressed into contact with a toner image carrier so as to intersect with the upstream surface of the toner image carrier at an acute angle, the tip of the blade is used as a toner image carrier. 1. A trail-type blade cleaning device comprising an elastic pressing member that presses upstream of a carrier and curves the blade so as to be concave toward the upstream side of the toner image carrier. (2) The trail-type blade cleaning device according to claim 1, wherein the elastic pressing member is made of a flexible plate material. (3) The trail-type blade cleaning device according to claim 2, wherein the flexible plate has a protruding member protruding from the surface of the plate at its tip end. (4) A trail-type blade cleaning device according to claim 2 or 3 of the utility model registration, characterized in that a flexible plate is attached to overlap the blade.