JPH04368984A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To prevent generation of a 'black stripe' on an image by restraining toner, having collected on a scraping side of an edge part, from transference to a position between a cleaning blade and a latent image bearing body. CONSTITUTION:The cleaning blade 6 is installed so that the edge part 6a is in a pressurized contact with a surface of a photosensitive body 1 in an axial direction of the photosensitive body 1. A magnetic force generating member 14 is placed in a position close to the edge part 6a on the back side of the cleaning blade 6 so that the magnetic toner remaining in the part A does not enter into a space between the edge part 6a and the photosensitive body 1. Thus, the movement of magnetic toner is restrained by the magnetic force generated by the magnetic force generating member 14.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is arranged in the axial direction of a latent image carrier, is driven to move toward and away from the latent image carrier, and has an edge portion pressed against the surface of the latent image carrier. The present invention relates to a cleaning device for an image forming apparatus that includes a cleaning blade that scrapes off magnetic toner remaining on the surface after a transfer process.

0002

2. Description of the Related Art In image forming apparatuses such as copying machines, printers, and facsimiles, electrophotographic or With electrostatic recording, after the toner image is transferred, toner that did not contribute to the transfer remains on the surface of the latent image carrier, so this is removed from the latent image carrier and collected. That's what I do.

Among such cleaning devices, those using a cleaning blade made of an elastic material such as rubber are relatively widely used. In such a cleaning device, the edge portion of the cleaning blade is brought into pressure contact with the surface of the latent image carrier to scrape off residual toner on the surface. At this time, fine paper dust contained in the toner is also removed together with the toner.

[0004] While cleaning the latent image carrier as described above, toner accumulates in the wedge-shaped portion formed by the edge portion on the scraped surface side and the photoreceptor 1. Then,
This accumulated toner gets between the cleaning blade and the photoconductor, and if the toner that gets in gets stuck in that area in the form of a lump, the edge of the cleaning blade will be covered with the lump of toner. It is pushed up, and there is a gap between the edge and the latent image carrier.
This creates gaps, and toner slips through these gaps.
"Black streaks" on images are more likely to occur.

In an image forming apparatus in which the cleaning blade is intermittently separated from the latent image carrier, when the cleaning blade is separated, an extremely thin flexible plate provided on the lower surface of the cleaning blade is moved relative to the cleaning blade. By making this tip protrude from the edge portion while sliding, the adhered toner is scraped off.

Even with such a configuration, toner accumulated on the edge of the cleaning blade may enter between the edge and the latent image carrier before the edge of the cleaning blade is cleaned. If this happens, there is a risk that the toner or paper dust that has gotten into the image may cause problems such as arrow marks and "black streaks" on the image. If the cleaning of the edge portion of the cleaning blade is incomplete and the toner adhering to that portion cannot be completely removed, the occurrence of such “black streaks” becomes more noticeable.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the toner accumulated on the scraping surface side of the edge portion from moving to a position between the cleaning blade and the latent image carrier, thereby improving the image quality. The purpose is to prevent or reduce the occurrence of "black streaks" on the skin.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention is arranged in the axial direction of a latent image carrier, is driven toward and away from the latent image carrier, and has an edge portion. In the cleaning device of the image forming apparatus, which is equipped with a cleaning blade that scrapes off the magnetic toner remaining on the surface of the latent image carrier after the transfer process, the magnetic toner is scraped off and removed from the surface of the latent image carrier. In order to prevent the toner accumulated on the scraped surface side of the edge portion from entering between the edge portion and the latent image carrier, a magnetic force is applied to the toner accumulated on the scraped surface side of the edge portion. We propose a configuration in which a magnetic force generating member is provided on the back side of the cleaning blade to attract and hold the cleaning blade and to apply the magnetic force over the entire area in the direction in which the cleaning blade is disposed.

[0009] It is effective to provide a driving means for displacing and driving the magnetic force generating member from a position where it exerts magnetic force on the toner on the edge side of the cleaning blade to a position where the magnetic force does not substantially reach the toner.

[0010] Further, if a driving means is provided for displacing and driving the magnetic force generating member along the back surface of the cleaning blade from a position where it applies magnetic force to the toner on the edge side of the cleaning blade to a position separated from the edge, Effective.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a drum-shaped photoreceptor which is an example of the structure of a latent image carrier, and is adapted to be rotated clockwise in the figure. During this rotation, the surface of the photoreceptor 1 is uniformly charged by the charger 2. Next, the surface is irradiated with a light image indicated by arrow P,
As a result, a predetermined electrostatic latent image is formed on the surface of the photoreceptor.

This electrostatic latent image is visualized as a toner image by the developing device 3. This toner image is transferred onto transfer paper 5 by the action of transfer charger 4 . After this transfer, the transfer paper 5 is separated from the photoreceptor 1 by a separation claw 10, and is discharged from the image forming apparatus through a fixing device (not shown).

[0013] In this image forming apparatus, a magnetic toner is used to visualize an electrostatic latent image by a developing device. The present invention is applied to an image forming apparatus using such magnetic toner. After the transfer process, the magnetic toner that did not contribute to the transfer remains on the surface of the photoreceptor 1, but this is scraped off from the surface of the photoreceptor by the cleaning blade 6 of the cleaning device 100. .

The cleaning blade 6 is made of an elastic material such as urethane rubber, and is disposed in the axial direction of the photoreceptor 1. The toner is scraped off by the edge portion 6a of the cleaning blade 6 coming into pressure contact with the photoreceptor 1, and at this time, foreign matter such as paper dust is also removed along with the toner. In the illustrated embodiment, the cleaning blade 6 is arranged in a trailing direction with respect to the rotation direction of the photoreceptor 1, but this blade 6 may be arranged in a counter direction with respect to the rotation direction of the photoreceptor 1. .

The cleaning blade 6 is attached to a blade attachment member 7 via a blade holder 8. The blade attachment member 7 is swingably attached to the shaft 9 at its base end. Due to the action of a spring 11 attached to the shaft 9, the blade attachment member 7 is given a dextrorotary behavior. The edge portion 6a of the cleaning blade 6 is pressed against the surface of the photoreceptor 1 by the force of the spring 11.

If the cleaning blade 6 remains in pressure contact with the photoreceptor 1, the edge portion 6a may be deformed, resulting in poor durability. Therefore, in this example, the cleaning blade 6 is separated from the photoreceptor 1 during non-cleaning, for example, every time the photoreceptor 1 is stopped. That is, by energizing the solenoid indicated by 12,
The blade attachment member 7 is rotated until it stops on the stopper pin 13, and the cleaning blade 6 is separated from the photoreceptor 1 as shown in FIG. Further, in the configuration in which the edge portion itself is cleaned as described above, the solenoid 12 is energized every time image formation is completed a plurality of times, and the cleaning blade is intermittently separated from the photoreceptor. In any case, the cleaning blade 6 is driven to move toward and away from the photoreceptor 1.

In FIG. 1, as the cleaning continues, a mark A formed between the edge portion 6a and the photoreceptor 1
Toner will accumulate in the wedge-shaped area shown in . When this happens, as mentioned above, the toner T containing paper powder etc. gets into between the edge portion 6a and the photoreceptor 1, creating a "gap" between the edge portion and the photoreceptor. Toner may slip through these gaps, causing black streaks and the like to appear on the image.

Edge portion 6a of cleaning blade 6
On the back side, which is the opposite side, a magnetic force is applied to the toner T accumulated in the section A so that the toner T does not enter between the edge section 6a and the photoreceptor 1.
A magnetic force generating member 14 is provided for attracting and holding this on the scraped surface side of the edge portion.

In this example, the magnetic force generating member 14 is made of a rod-shaped permanent magnet, is disposed in the axial direction of the photoreceptor 1, and exerts magnetic force over the entire area in the direction in which the cleaning blade 6 is disposed. It becomes. In addition, in 1987,
- As shown in Publication No. 176464, a technique has been proposed in which a block-shaped magnet is provided only on the side edge of the cleaning blade, but with this, the side sealing function is achieved by the magnetic force of the magnet. It is now possible to do so.

The toner T accumulated in the area A due to the magnetic force of the magnetic force generating member 14 is itself a magnetic toner, so it is mixed with paper powder etc. that are attached to the toner particles due to physical force. As a result, it is brought to the scraped surface side portion of the edge portion 6a and held there by suction. That is, Figure 4
As shown in FIG. 2, the toner T is attracted and held on the toner scraping surface side part with a force F due to the magnetic force of the magnetic force generating member 14. This makes it difficult to move.

If the toner does not move into this gap, the edge portion 6a will not rise as described above, and the toner will be prevented from slipping through this gap. In the end, cleaning defects are eliminated and the occurrence of "black streaks" can be suppressed.

In response to the separation operation of the cleaning blade 6, the magnetic force generating member 14 is driven to be displaced from a position where it exerts magnetic force on the toner on the edge portion 6a side to a position where the magnetic force does not substantially reach the toner. , the toner adsorbed and held on the edge portion 6a side can be dropped.

In FIG. 1, a magnetic force generating member 14 is provided at the free end.
The base end of the mounting member 15 is swingably attached to the shaft 16. Due to the action of a spring 17 attached to the shaft 16, the mounting member 15 is given a right-handed rotational behavior. Due to the force of the spring, the magnetic force generating member 14 is pressed against a portion of the back surface of the cleaning blade 6 near the edge portion 6a.

A solenoid 18 is connected to the attachment member 15, and when the cleaning blade 6 separates from the photoreceptor 1, for example, the solenoid 18 is activated at the same time as the cleaning blade separates from the photoreceptor 1. is excited. Then, the attachment member 15 rotates around the shaft 16 to a position where it is stopped by the stopper pin 19, and at this position, the magnetic force generating member 14 becomes separated from the cleaning blade 6, as shown in FIG.

This distant position is a position where the magnetic force does not substantially reach the toner on the edge side. When the magnetic force generating member 14 is displaced to such a position, the toner containing paper dust and the like, which is attracted and held on the edge portion 6a side, falls. As a result, when cleaning is performed next time, even if some toner remains and adheres to the cleaning blade 6, the amount of toner adhering to the edge portion is reduced, and the ability to remove the toner quantitatively can be improved.

It should be noted that a structure may be adopted in which the spring 17 is not provided and the magnetic force generating member 14 is placed on the back surface of the cleaning blade 6 by its own force. Both solenoids 12,
When the excitation of 18 is released, both mounting members 7
, 15 are rotated to the right by the force of the springs 11 and 17, respectively, and the cleaning blade 6 and the magnetic force generating member 14 return to the positions shown in FIG. 1, respectively. When using its own weight, the attachment member 15 will be rotated back to the position by the weight of the magnetic force generating member 14 .

In the example shown in FIG.
The magnetic force generating member is movably driven along the back surface of the cleaning blade 6 from a position on the edge side that exerts magnetic force on the toner on the a side to a position separated from the edge.

A magnetic force generating member 24 is fixed to the tip of the rod 22 connected to the plunger 21 of the solenoid 20, and when the solenoid 20 is energized, it slides on the back side of the cleaning blade 6 and cleans the edge. It is displaced from the solid line position on the part 6a side to the broken line position remote from the edge part. Note that the rod 22 is inserted through a blade holder 25 to which the cleaning blade 6 is attached.

For example, the cleaning blade 6 is attached to a blade attachment member 7 (FIG. 1) together with a blade holder 25, a solenoid 20, etc., and is configured to be able to pivot around an axis 9. The solenoid 12 is energized and the blade mounting member 7 is moved from the position of FIG.
When turning to the position shown in Figure 2, at the same time, or
After a slight delay, the solenoid 20 is energized. As a result, the magnetic force generating member 24 moves to a position separated from the edge portion 6a by the broken line.

With this movement, the toner T attracted and held by the edge portion 6a moves to the left in the figure while being held on the lower surface of the cleaning blade 6 by the magnetic force of the magnetic force generating member 24. At this time, the toner that has accumulated and become clumpy,
While changing its shape, it tends to collapse, and some toner falls off. After this, the excitation of the solenoid 20 is released, and along with this, the rod 22 is pulled to the right in the figure by the biasing force of a biasing member (not shown), and the magnetic force generating member 24 is moved to the solid line position. return.

When the magnetic force generating member 24 returns, the fallen toner is not brought to the edge portion 6a side, and some toner may remain near the B portion, so that the toner is not brought to the edge portion 6a. The amount of remaining toner is reduced, and as in the previous example, the ability to quantitatively remove toner during subsequent cleaning can be increased.

In the embodiment shown in FIGS. 1 and 2,
The attachment member 15, the shaft 16 that supports it, and the solenoid 18 displace the magnetic force generating member from a position where it exerts magnetic force on the toner on the edge side of the cleaning blade to a position where the magnetic force does not substantially reach the toner. However, instead of this configuration, for example, the attachment member 15 is fixed to the shaft 16 and a motor is provided to rotate the shaft 16, so that the cleaning blade 6 is not pressurized by the solenoid 12. The mounting member 15 and the magnetic force generating member 14 may be rotated to the position shown in FIG. 2 by turning on the clutch of the motor with a delayed timing. After the toner is dropped from the cleaning blade 6, the clutch is turned off and the magnetic force generating member 14 is returned to the position shown in FIG. 1 by its own weight. Alternatively, the shaft 16 to which the mounting member 15 is fixed is supported in a free state, and a handle directly connected to the shaft 16 is manually rotated to rotate the magnetic force generating member 14 and its mounting member 15 to the position shown in FIG. It can also be configured to do so.

Similarly, in the embodiment shown in FIG. 3, the solenoid 20 and the rod 22 move the magnetic force generating member away from the edge side of the cleaning blade from the position where it applies magnetic force to the toner. Although the driving means is configured to drive the cleaning blade along the back surface thereof to the position shown in FIG.

As the device for driving the blade attachment member 7, a motor or the like may be used instead of the solenoid 12.

Furthermore, in each of the embodiments described above, the magnetic force generating members 14 and 24 are moved to the position indicated by the broken line in FIG. 2 or 3 in conjunction with the movement of the cleaning blade 6 away from the photoreceptor 1. It is also possible to configure the magnetic force generating members 14 and 24 to be operated and controlled separately from the separating operation of the cleaning blade 6.

[0036]

According to the cleaning device according to claim 1, in a structure in which the cleaning blade is driven toward and away from the latent image carrier, toner accumulated on the edge portion side of the cleaning blade can be removed from the cleaning device. It can be prevented from entering between the edge portion and the latent image carrier,
Since the edge portion is prevented from rising from the surface of the latent image carrier, it is possible to suppress the occurrence of cleaning defects. This makes it possible to prevent the occurrence of "black streaks" on images, further improving the image quality. or,
Such functions can be achieved with an extremely simple configuration.

According to the configurations described in claims 2 and 3, when the cleaning blade is returned to the cleaning position,
Since the amount of toner and paper powder adhering to the edge portion can be reduced, the subsequent cleaning ability can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cleaning device according to an embodiment of the present invention and components surrounding a photoreceptor.

[Figure 2] Figure 1 shows a state in which the cleaning blade and magnetic force generating member are separated from the photoreceptor and cleaning blade.
This is an action diagram from .

FIG. 3 is a schematic configuration diagram of another embodiment.

FIG. 4 is a diagram for explaining the attraction and holding effect of toner due to magnetic force.

[Explanation of symbols]

1 Drum-shaped photoreceptor 6 as a latent image carrier Cleaning blade 6a Edge portion 14 Magnetic force generating member 24 Magnetic force generating member 100 Cleaning device

Claims (3)

[Claims] Claim 1: The transfer process is performed in a state in which the latent image carrier is disposed in the axial direction of the latent image carrier and is driven to move toward and away from the latent image carrier, and the edge portion is in pressure contact with the surface of the latent image carrier. The magnetic toner remaining on the surface is then scraped off in a cleaning device of an image forming apparatus equipped with a cleaning blade that scrapes off the magnetic toner remaining on the surface.
To prevent the toner accumulated on the scraped surface side of the edge portion from entering between the edge portion and the latent image carrier, a magnetic force is applied to the toner and the toner is attracted to the scraped surface side. 1. A cleaning device for an image forming apparatus, characterized in that a magnetic force generating member is provided on the back side of the cleaning blade to hold the cleaning blade and to apply the magnetic force over the entire area in the direction in which the cleaning blade is disposed. 2. A driving means for displacing and driving the magnetic force generating member from a position where it exerts magnetic force on the toner on the edge side of the cleaning blade to a position where the magnetic force does not substantially reach the toner. Cleaning device for image forming apparatus. 3. A driving means for displacing and driving the magnetic force generating member along the back surface of the cleaning blade from a position where it applies magnetic force to toner on the edge side of the cleaning blade to a position separated from the edge. Item 1. A cleaning device for an image forming apparatus according to item 1.