JP3063885B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer.

[0002]

2. Description of the Related Art Conventionally, in a known image forming apparatus,
It is difficult to transfer all the toner of the toner image formed on the surface of the image carrier to the transfer material at the time of transfer, and it is inevitable that some toner remains on the image carrier. For this reason, it is necessary to sufficiently clean the toner remaining on the image carrier even after the transfer every time the transfer is performed.

For this reason, various types of cleaning means have been conventionally proposed. However, such a cleaning means as to remove the transfer residual toner by abutting the edge of a cleaning blade made of an elastic member such as rubber on an image carrier is proposed. It is well known that it is already widely used because of its simple structure, low cost, and excellent toner removal function.

FIG. 9 shows an example of a known cleaning device, which has an axis perpendicular to the plane of the drawing and has a rotating cylindrical shape around which a charger, a developing device, a transfer means and the like (not shown) are arranged. The cleaning device C is arranged close to the image carrier 1. The image carrier has a photoconductor on the outer periphery, and a photoconductor is used as the photoconductor. Examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OPC). included. The shape on which the photosensitive member is mounted includes, for example, a rotating member such as a belt shape in addition to a drum shape. Generally, a drum-shaped or belt-shaped one is used, and in the case of the drum-type photoconductor of this example, a photoconductor is deposited or coated on a drum cylinder made of aluminum alloy or the like. It is a thing.

The cleaning device C has a cleaning container 2 having an opening and the like in the direction of the image carrier 1, and one edge of a cleaning blade 3 made of urethane rubber or the like is formed in the opening. One edge of the other edge of the blade 3 is in contact with the image carrier 1, and when transfer residual toner generated at a transfer portion (not shown) reaches the edge of the cleaning blade 3, Scraped off by

The inside of the cleaning container 2 is divided by a partition plate 6 into a toner storing section 7 and a scraping section 10, and a scraping member 8 having rotating blades is disposed below the scraping section 10. is there. The toner scraped off from the image carrier 1 by the cleaning blade 3 falls into the cleaning container 2 by the rake sheet 4, and then is moved further inward than the partition plate 6 by the scraping member 8 rotating in the direction of the arrow shown in the figure. The toner is conveyed and stored in the toner storage unit 7. With such a configuration, the toner can be forcibly fed into the storage unit 7 until the toner density becomes considerably high, so that a large amount of toner can be stored in the small volume space, and the container can be downsized. Reference numeral 5 in the figure
Is a magnet for preventing the spilled toner from spreading widely and contaminating other members.

Conventionally, the charging and transferring means of this type of image forming apparatus charges or transfers contact charge (especially a charging roller) using a charging roller or a charging blade from the viewpoint that the power supply capacity can be reduced in terms of current. The number of cases to be used is increasing.

On the other hand, contact charging greatly affects the photoreceptor due to electric discharge. Therefore, the same photoreceptor is used under the same cleaning conditions, and a corona charger is used as a charging / transfer unit, and a charging roller is used. When compared with each other, a difference appears between the two in terms of the shaving amount of the photoconductor. As an example, when a copying machine having a corona charger for charging and transferring is used for 10,000 sheets under the same photosensitive member and the same cleaning conditions at a process speed of 200 mm / sec, the shaving amount of the photosensitive member is 1.5 to 2. 0 μm / 10,000 sheets. On the other hand, in a copying apparatus in which the charging transfer means is a charging roller, when 10,000 sheets are used, the shaving amount of the photoreceptor becomes 3.0 to 3.5 μm / 10,000 sheets.

[0009]

However, in the above-described apparatus, a part of the toner sent to the storage section by the scraping member returns to the scraping section again with the rotation of the scraping member. Therefore, as the use of an image forming apparatus, for example, a copying apparatus, progresses, the amount of toner accumulated in the scraping unit increases, and the toner aggregates.
The pressure of the toner on the photoreceptor on the surface increases.
As a result, for example, when the drum cylinder is eccentrically rotated, uneven shaving of the photoconductor occurs in the rotation cycle of the image carrier, and since both ends of the cleaning container have walls, the toner is pressed and is close to the wall. Since the agglomeration degree is higher in the portion than in the portion other than the end portion, there is also a problem that the shaving of the photoconductor is more at both end portions than at the center portion.

Further, such agglomeration of the toner makes it difficult for foreign matter such as paper dust removed from the surface of the photoreceptor to be removed from the vicinity of the photoreceptor, thereby causing a problem that the image carrier is damaged. Often. When the charging / transferring means is corona-charged, such a problem is less likely to occur even when using the configuration of the conventional cleaning device because the shaving amount of the photoreceptor is small. However, the difference between the scratched part and the part with the uneven shaving and the part that is not so is hard to be noticed and the degree is light.

However, when the charging / transferring means is a contact charging member such as a charging roller, the amount of shaving of the photoreceptor becomes large, so that the difference in shaving unevenness tends to be noticeable. Image deterioration due to scratches on the photoreceptor becomes significant. This phenomenon becomes more remarkable when the alternating voltage AC is applied to the charging means.

In order to solve the above-mentioned problems, Japanese Patent Publication No. Sho 61-2
The invention described in Japanese Patent No. 2315 discloses a method in which a rake sheet in contact with a photoreceptor is movable, a rake sheet is vibrated by rotation of a scraping member, and a scraping plate is provided which can abut against an antinode of one surface of the scraping member. ing.

In Japanese Patent Application Laid-Open No. Hei 2-212875, a partition plate is rotatably supported near a top plate of a cleaning container, and the partition plate is urged toward a scraping member by a spring.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus provided with a contact charging means and provided with a cleaning device having a simple configuration and having no toner backflow or scattering.

[0015]

According to a first aspect of the present invention, there is provided an image forming apparatus having a contact charging means, wherein a toner removed from an image carrier after a transfer step is scraped to a toner reservoir in a cleaning device. A scraping means provided rotatably around the moving shaft, a partition member elastically pressed against the scraping means and swinging with the rotation of the scraping means, and a root of the partition member fixed. , have a cleaning apparatus provided with a partition wall to isolate the cleaning chamber to the reservoir portion scraping except downward, said partition member is double
An image forming apparatus comprising several layers .

With this configuration, damage to the surface photosensitive layer of the image carrier can be prevented easily and at low cost.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 10 is a longitudinal sectional view of an electrophotographic image forming apparatus according to one embodiment of the present invention.

In FIG. 10, a glass platen 11 for loading a document is for placing a document to be copied.
The illumination lamp 12 scans the entire original by moving in the direction of arrow a while irradiating the original placed on the original table 11 with light. The reflected light obtained by irradiating the original with the illumination lamp 12 is a movable first mirror group 13a for keeping the optical path length constant, a zoom lens 14,
Further, the image carrier (electrophotographic photoreceptor) 1 is rotated in the direction of the arrow shown in the drawing and uniformly charged by the charging roller 16 in advance via the fixed second mirror group 13b and the third mirror 13c.
An image is formed thereon, and an electrostatic latent image is formed.

Around the image carrier 1, a primary charging roller 16, a developing device 1
7. A cleaning device C and the like are provided. The electrostatic latent image formed on the image carrier 1 is developed by a developing unit 17 and visualized.

At the bottom of the apparatus main body, a paper feed cassette 19 for stacking and storing sheets S is provided so as to be able to be pulled out in a direction perpendicular to the plane of the drawing. The sheets S stacked and stored in the sheet cassette 19 are lifted upward by the middle plate 20 and pressed against the sheet feeding roller 21. Further, a separation pad 22 provided so as to press the corner of the sheet S elastically is pressed against the paper feed roller 21.

When the sheet feeding roller 21 rotates, the sheet S is sequentially fed from the uppermost sheet of the sheet S,
The paper is separated and fed when passing between the paper and the separation pad 22. The separated and fed sheet S is guided to a registration roller pair 24 that is temporarily stopped via a conveyance guide 23. The registration roller pair 24 synchronizes with the developed image formed on the image carrier 1 and conveys the sheet S to the transfer unit. The transfer roller 25 is in pressure contact with the image carrier 1. When the sheet S conveyed by the pair of registration rollers 24 passes between the image carrier 1 and the transfer roller 25, a developed image is transferred. The sheet S to which the image has been transferred is conveyed by the conveying device 26, and heat and pressure are applied when passing through the fixing unit 27 to fix the transferred image. The sheet S on which the image has been fixed is conveyed and discharged to a discharge tray 29 by a discharge roller 28. The image carrier 1 after the transfer is further rotating, and the residual toner after the transfer remaining on the image carrier 1 is removed by the cleaning device C.

FIG. 1 is a side sectional view of a cleaning apparatus C according to an embodiment of the present invention, in which parts corresponding to those shown in FIG. 9 are denoted by the same reference numerals. The explanation of is incorporated.

The rotating shaft 30 to which the scraping member 8 is fixed is
The cleaning container 2 is rotatably supported by the cleaning container 2, and is driven to rotate clockwise as indicated by the arrow in FIG. The tip of the scraping member 8 is provided so as to approach or contact a support plate 31 for fixing the rake sheet 4 to the cleaning container 2.

The root of an elastic partition member 9 is fixed to a partition plate 6 fixed or integrally formed on the top plate and both side plates of the cleaning container 2. The leading end of the partition member 9 approaches or contacts the support plate 31 of the rake sheet 4 at a position retreated from the leading end of the scraping feed member 8. Partition member 9
Is pressed against the rotating shaft 30 with elasticity, the partition member 9 is always in contact with the scraping member 8, and the amount of deformation varies depending on the rotational position of the scraping member 8. In the above description, the length of the partition member 9 and the scraping member 8 perpendicular to the plane of FIG. 1 is substantially equal to the length of the image carrier 1.

As the transfer residual toner that is generated at the transfer portion where the transfer roller 25 is pressed against the image carrier 1 and adheres to the surface of the image carrier 1, as the peripheral surface of the image carrier 1 moves in the direction indicated by the arrow in FIG. The waste toner scraped off by the cleaning blade 3 and received in the cleaning container 2 by the rake sheet 4 is then transported and stored by the scraping member 8 in the storage portion 7 on the back side of the cleaning container 2. It is the same as the known one shown in FIG.
However, since the partition member 9 is constantly pressed against the scraping member 8, the flow of the waste toner into the scraping portion 10 is
Greatly reduced.

That is, as shown in FIGS. 1 to 4, the tip of the scraping member 8 removes the waste toner on the support plate 31 from the right in FIG. Send left. At this time, even if the storage section 7 is full of waste toner, the waste toner is not returned to the scraping section 10 because it is hindered by the partition plate 6 and the partition member 9.

The bottom surface of the cleaning container 2 is horizontal or inclined such that the waste toner does not move due to the inclination.

In such an apparatus, since the charging and transferring means is contact charging, the shaving amount of the photoreceptor is larger than that of corona charging. However, since the partition member 9 is constantly pressed against the scraping member 8, the recirculation of the waste toner to the scraping portion 10 is suppressed by the sealing effect. Accordingly, the residual toner in the scraping section 10 is kept small, so that aggregation of the toner in the scraping section 10 is suppressed, and foreign matter such as paper dust is easily discharged from the periphery of the photoreceptor. It has the effect of preventing scratches and extending the life of the photoreceptor.

FIG. 5 is a characteristic portion of the cleaning device
It is a longitudinal section showing details of a certain partition member. In the present embodiment, the partition member 9 has a two-layer structure including, for example, a tough polyester film 9-2 and a urethane film 9-1 serving as a damper. The purpose of this purpose is to make the sound generated when the partition member 9 oscillates along with the rotation of the scraping member 8 when the partition member 9 rubs against the scraping member 8 while maintaining the strength of the partition member 9 (partitioning). (Because the member 9 is configured to be pressed against the scraping member 8) and to reduce the impact.

The pressure at which the partition member 9 is pressed against the scraping member 8 is determined by the thickness of a tough member such as the polyester film 9-2.
Is made of only the tough polyester film 9-2, for example, 15
When a film having a thickness of about 0 μm is used, the scraping member 8
When swinging with the rotation of, the pressure with the scraping member 8 is reduced (FIG. 7), and the sound and vibration generated when the pressure with the scraping member 8 increases again (FIG. 6) are large. There are disadvantages. Conversely, when the thickness of the film is reduced to suppress sound and vibration, the sealing ability of the partition member 9 is weakened. In particular, when the amount of waste toner accumulated in the storage section 7 increases, the Since the pressing force against the scraping feed member 8 is weak, the swinging is weakened, and the waste toner is
Reflux to 0. Therefore, the effect of suppressing the damage of the photoconductor described above may be reduced.

When the partition member 9 is formed of a single layer, it is difficult to achieve both sound and vibration and sealing ability. However, if the partition member 9 is formed of a plurality of layers (for example, a tough polyester film 9-2 and a urethane film 9-1 serving as a damper), one of the polyester films 9-2 is thickened and pressed. Since the urethane film 9-1 has a role as a damper even when the force is increased, the sound and vibration generated by being pressed against the scraping member 8 with the rotation of the scraping member 8 can be suppressed. However, there is an advantage that the sealing ability can be maintained at the same time.

From the above, the partition member is composed of a plurality of layers.
This has the advantage that the damage to the photoreceptor is suppressed, and the noise and vibration when the partition member hits the scraping member can be reduced while maintaining the sealing performance of the partition member.

The bottom surface of the cleaning device is horizontal or inclined so that the waste toner does not move, and FIG. 8 is equivalent to the sectional view shown in FIG. By doing so, the cleaning device itself becomes compact and a small-diameter drum (for example, a
This cleaning device can also be used when a drum having a diameter of about 0 mm) is used. Also the bottom is not horizontal,
Since it is close to that, a small amount of waste toner that is not sent to the storage unit 7 by the scraping member 8 remains on the rake sheet 4 around the photosensitive member (for example, a dead space hatched portion shown in FIG. 8). Even if a large number of similar documents (documents with characters in the same portion) are copied in this state, a small amount of waste toner remains in advance over the entire width of the cleaning device.
There is no shaving unevenness of the photoreceptor between a portion having a character (a portion where the waste toner comes out) and a portion having no character (a portion where the waste toner does not come out).

From the above, the bottom surface of the cleaning device
If it is horizontal or inclined so that the waste toner does not move, there is an advantage that damage to the photoconductor is suppressed, and even if a large number of similar documents are copied, uneven shaving of the photoconductor hardly occurs.

If the tip of the scraping member 8 is close to or in contact with the bottom surface of the cleaning device C, and the tip of the partition member 9 is located closer to the position retreated than the tip of the scraping member 8, the waste toner can be stored. Since the ability to send the waste toner to the unit 7 and the sealing performance for keeping the waste toner in the storage unit 7 are improved, a compact cleaning device can be obtained.

[0037]

As described above, according to the first aspect of the present invention, in an image forming apparatus having a contact charging means, it is possible to suppress the occurrence of uneven scraping and flaws of an image carrier with a low cost and simple structure. Chi also an effect that it is possible to extend the life, and, or holding the sealing capability of the partition member
Further, generation of sound and vibration can be suppressed.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing the operation of FIG.

FIG. 3 is a side sectional view showing the operation of FIG. 1;

FIG. 4 is a side sectional view showing the operation of FIG.

FIG. 5 is a side sectional view of a main part of the embodiment of the present invention.

FIG. 6 is a side sectional view showing the operation of FIG. 5;

FIG. 7 is a side sectional view showing the operation of FIG. 5;

FIG. 8 is a side sectional view of an embodiment of the present invention.

FIG. 9 is a side sectional view of a conventional cleaning device.

FIG. 10 is a longitudinal sectional view of an embodiment of an image forming apparatus to which the present invention is applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image carrier 2 cleaning container 3 cleaning blade 4 rake sheet 6 partition plate 7 storage section 8 scraping member 9 partition member 10 scraping section

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-313542 (JP, A) JP-A-6-342237 (JP, A) JP-A-6-301272 (JP, A) 36454 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 21/10-21/12 G03G 15/02

Claims (1)

(57) [Claims] An image forming apparatus having a contact charging means is provided so as to be rotatable around a rotation axis for scraping toner removed from an image carrier after a transfer step to a toner storage section in a cleaning device. A scraping means, a partition member elastically pressed against the scraping means, and swinging with the rotation of the scraping means, and fixing the root of the partition member,
Have a cleaning apparatus provided with a partition wall to isolate the cleaning container to have part and storage part scraping except downwards, before
An image forming apparatus, wherein the partition member has a plurality of layers .