JPS6356998B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor cleaning device for a copying machine.

If the copying machine is a transfer type, the toner image developed on the photoreceptor is not entirely transferred to the transfer paper, but generally a small portion of the toner layer on the photoreceptor side is left behind. It will be done. Such residual toner must be removed from the photoreceptor surface in preparation for the next copying. A photoreceptor cleaning device is used for this purpose.

There are various types of conventionally known photoreceptor cleaning devices, such as a fur brush type, a blade type, a web type, and a magnetic brush type. The fur brush type originally uses a soft bristle brush such as rabbit hair, but in recent years resin bristles have also been used, which has the advantage of not damaging the photosensitive surface. On the other hand, there are disadvantages in that the removed toner scatters and the brush bristles come off and get mixed into the developer or adhere to the photosensitive surface. The blade type uses a rubber blade to rub against the photoreceptor surface, and while it is highly effective in removing it, it tends to damage the photoreceptor surface and requires some effort to make the contact surface uniform with the photoreceptor. The web type uses a soft cloth belt to rub the photosensitive surface, and has an effect between the fur brush type and the blade type, but requires a large device to drive the cloth belt. The magnetic brush type attracts magnetic powder to the surface of a non-magnetic sleeve containing a magnet inside to form a magnetic brush, which rubs the photosensitive surface. Although it does not have the above disadvantages, it is usually Since the position where the removed toner falls is a fixed position, if the toner has no fluidity, the fallen toner will gradually accumulate and become like a stone tray, and depending on how the cleaning device is arranged, the tip of the toner may become exposed to light. This has the disadvantage that the toner collection container is generally inefficiently used.

According to the present invention, a stationary non-magnetic sleeve disposed in contact with or close to the surface of a photoreceptor; and a rotatable magnet element having a plurality of magnetic poles housed inside the non-magnetic sleeve in a longitudinal direction. and a toner collection container for removing magnetic toner adsorbed onto the surface of the non-magnetic sleeve. According to the photoreceptor cleaning device according to the present invention, the magnetic toner removed from the surface of the non-magnetic sleeve flows down along the non-magnetic wall surface of the toner collection container while being attracted by the magnet rotating within the sleeve, so that the toner can be collected. Since the toner is transported to the innermost part of the container and is sequentially deposited from there, the entire toner collection container can be effectively used to store the toner, and there is no need to form a stone trap as in the conventional case.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photoconductor cleaning device that can effectively recover toner removed from a photoconductor surface in a copying machine that uses magnetic toner.

Hereinafter, the present invention will be described with reference to the attached drawings. FIG. 1 is an external perspective view showing an example of an electrophotographic copying machine equipped with a cleaning device according to the roller invention, and FIG. 2 is a longitudinal cross-sectional view thereof, and reference numeral 1 designates the entire copying machine. On the top surface of the copying machine 1, there are a contact glass 2 (shown only in FIG. 2) on which an original is placed, and a pressure plate 3 that presses down the original placed on the contact glass 2 (shown only in FIG. 2).
(shown only in FIG. 1) are provided respectively.
The upper portion 1A of the copying machine 1 can be rotated upward, as shown by the chain line in FIG.
In Fig. 1, reference numeral 4 designates the operating section, 5 a pull-out sheet cassette, 6 a copy receiver for receiving copies ejected from the paper output port 7, and 8 a cold air inlet hole. It shows.

In FIG. 2, a charging/exposure unit 9 serving as an exposure device is arranged below the contact glass 2, and a photoreceptor belt device 10 made of an OPC photoreceptor or the like is further arranged below it.

The charging/exposure unit 9 includes an illumination lamp 1 that illuminates the document on the contact glass 2 in a slit shape.
1. An imaging optical system 12 consisting of a convergent light transmission array that transmits the illuminated original image to the photoreceptor belt 13 of the photoreceptor belt device; prior to exposure by the imaging optical system, the photoreceptor belt 13 is It consists of a charger 14 that charges to a specific polarity, a high voltage generator 15 for supplying high voltage power to the charger, and a support 16 that supports each of these devices substantially integrally.

The charging/exposure unit 9 moves the imaging optical system 12 forward by a length L from the starting position St to the ending position E, and then returns to the starting position St, along a guide rail to be described later. It's getting old.

The photoreceptor belt device 10 includes a drive roller 1
7. A driven roller 18, a tension roller 19, and a photoreceptor belt 13 wrapped around each of these rollers.
and a guide plate 20 for keeping the belt flat. When the charging/exposure unit 9 moves forward, the photoreceptor belt 13 is stopped, and the photoreceptor is charged by the charger 14, and by the illumination lamp 11 and the imaging optical system 12. The image is then exposed and scanned to form an electrostatic latent image corresponding to the original image. When the charging/exposure unit 9 reaches the terminal position E, the photoreceptor belt 13 rotates in the direction of the arrow, and the electrostatic latent image is visualized by a developing device to be described later.

The photoreceptor belt 13 is made up of two segments: a first image forming area 13A extending from point a to point b, and a second image forming area 13B extending from point c to point d. Thereafter, the rotating photoreceptor belt 13 is temporarily stopped when point a is located at point c and point b is located at point d. That is, the photoreceptor belt 13 has the distance between a and b and cd
The circumferential length l is determined so that the distances between the image forming areas are equal to each other, and the distances between a and b and between b and c are also equal between the image forming areas. Therefore, when the belt rotates after one exposure operation, the belt 13 moves by 1/2.

When the photoreceptor belt 13 rotates by 1/2, the electrostatic latent image formed in the first image forming area 13A at this time is visualized by the dry developing type developing device 21. This first visible image is parked at the underpass portion of the belt.

On the other hand, when the photoreceptor belt 13 rotates by 1/2 and once stops, the charging/exposure unit 9 starts the second forward movement and moves to the second image forming area 1.
An electrostatic latent image is formed on 3B. When the unit 9 reaches the terminal position E, the photoreceptor belt 13 starts rotating again and moves by 1/2, and during this time the developing device 2
1 forms a second visible image.

When the photoreceptor belt 13 rotates again, the copy sheet sent out from the sheet cassette 5 is brought into contact with the first visible image that has been waiting until now, and transferred to the first visible image by the transfer charger 22. Visual images can be transferred. After this, a second visible image is parked at the underpass portion of the belt. The copy sheet onto which the first visible image has been transferred is transferred to a fixing device 23
After the visible image is fixed thereon, the sheet is discharged onto the copy tray 6 by a pair of discharge rollers 24.

Copy sheets (not shown) are stacked and stored in the sheet cassette 5, and the copy sheets are
Only the topmost sheet is sent out by the paper feed roller 25 and separation claw 26, and the registration roller pair 27 controls the movement (rotation of the belt) of the visible image waiting at the underpass portion of the belt. The photoreceptor belt 13 is synchronously conveyed while being in contact with the photoreceptor belt 13, and a visible image is transferred thereto.

After the transfer of the visible image, the surface of the photoreceptor belt 13 is cleaned by the cleaning device 28 according to the present invention, which is disposed downstream of the transfer charger in these rotating directions.
Prepare for the next charging and exposure process.

As described above, while the photoreceptor belt 13 is stopped, the charging/exposure unit 9 is moved forward to form an electrostatic latent image, and then, while the belt is rotated by 1/2, the latent image is formed. By repeating the process of making a visible image, waiting for a while, and transferring this visible image to the copy sheet the next time the belt rotates,
For example, multiple copies can be made from one original.

By the way, as mentioned above, the upper part 1A of the copying machine shown in FIG. 2 can be opened and closed.
The upper part 1A of the copying machine is able to swing open and close relative to the lower mechanism about a pivot shaft 29, and can be moved to any opening angle position by a friction braking mechanism 30 including a sector gear and gears meshing therewith. It can be stopped with.

The above-mentioned charging/exposure unit 9, photosensitive belt device 10, and cleaning device 28 are installed in the upper part 1A of the copying machine. Furthermore, one ends of light-shielding curtains 33 and 34 wound around winding drums 31 and 32, the details of which will be described later, are fixed to the front and rear ends of the charging/exposure unit 9, so that the light transmitted through the contact glass 2 is exposed to light. This prevents the photosensitive surface of the belt 13 from being inadvertently exposed.

Further, a cooling fan 35 for preventing the illumination lamp 11 from overheating is provided at one end of the upper portion 1A of the copying machine.

At the bottom of the copying machine, there is the sheet cassette 5 mentioned above.
a paper feeding mechanism including a paper feeding roller 25 and a registration roller pair 27; the developing device 21; and the fixing device 2.
3 and a drive motor 3 as a drive source of the copying machine.
6 are each equipped. The upper mechanism and the drive motor 36 are connected by a drive force transmission mechanism (not shown).

Next, the developing device 21 will be explained with reference to FIGS. 2 and 3. This developing device 21 is
A magnetic toner, which is a one-component developer in which magnetic powder is mixed into resin toner, is used.
It is stored in 8. A sleeve 39 made of a non-magnetic material and rotatable in the direction of the arrow, and a plurality of magnets 40 fixed inside the sleeve are disposed in the casing 37. Further, a doctor 41 is arranged close to the outer peripheral surface of the sleeve 39. A developer discharge port 38a is formed in a part of the container 38, and this discharge port is closed with a lid 38b before being attached to the casing, as shown by the solid line in FIG. The lid 38b is slidable relative to the container body, and a bent portion 38c is formed in a portion thereof.

Then, the container 38 with the lid 38b closed
As shown by the chain line in FIG. 3, the casing 37
When the lid body 38 is attached to the container holding part 37a, the bent part 38c engages with a part 37b of the holding part.
b is locked, so when the container 38 is completely pushed in, the discharge port 38a will be opened. The developer discharged and supplied into the casing 37 from the opened discharge port 38a is supplied to the photoreceptor belt 13 and consumed by the action of the magnet 40 and the rotating sleeve 39. The developer container 38 is replaced while the upper part 1A is swung up as shown by the chain line in FIG. Note that the upper portion 1A can be swung further than the position shown by the chain line in FIG. 2. When the container 38 is configured as described above, it can be attached to the casing with the discharge port 38a closed, so that when replenishing the developer, the developer can be replenished without causing the developer to scatter, thereby ensuring that there is no contamination due to developer scattering. It can be prevented.

The above explanation will be sufficient as an overall explanation of the copying machine to which the present invention is applied.

Next, the cleaning device 28, which is the subject of this invention, will be explained. Generally, as a means for forming a magnetic brush, a plurality of magnets are arranged inside a sleeve made of a non-magnetic material so that adjacent magnets have different polarities, and one or both of the sleeve and the magnets are rotated to form a sleeve. It is designed to adsorb developer on its surface. In any case, it is desirable that the magnetic field on the sleeve surface be formed equally over the entire circumference and length of the sleeve.

By the way, conventionally, for one ferromagnetic material,
They were magnetized so that adjacent polarities were opposite to each other. Therefore, the weight of the magnet increases,
In the case of a type in which this is rotated, there is a drawback that the rotational load increases. In particular, when rotating a magnet, the lines of magnetic force are required to exist densely, which inevitably increases the number of magnetized poles.
This has the disadvantage that it results in a magnet with poor orientation.

The magnet used in the cleaning device 28 eliminates the above drawbacks. In FIG. 2, the cleaning device 28 includes a fixed sleeve 42 made of a non-magnetic material such as aluminum or non-magnetic stainless steel, a magnet element 43 that rotates counterclockwise inside the sleeve 42, a casing 44, and a toner collection container. It consists of 45.

As shown in FIG. 4, the magnet element 43 includes, in this example, a yoke 46 made of a ferromagnetic material having four fins 46a extending in the axial direction, and four magnets 47 arranged between the fins. It is fixed to the rotating shaft 48. The magnet 47 and the yoke 46 may be made substantially integral with each other by an adhesive;
Alternatively, as shown in FIG. 5, the two may be combined and then inserted into a heat-shrinkable tube and heated to be integrated with each other.

The magnet 47 is magnetized, for example, as shown in FIG. 5, with the north pole facing outward and the south pole contacting the yoke 46 made of a ferromagnetic material. As a result, an S pole is generated at the tip of the fin 46a of the yoke, and a magnetic field is formed between this and the N pole of the adjacent magnet 47. In the magnet element 43 having such a configuration, since magnets of the same standard can be used, it has the advantage that it can be manufactured at low cost, has good magnetic field orientation, and can be lightweight.

As shown in FIG. 6, the toner collection container 45 is
A non-magnetic guide portion 45a that follows the circumferential surface of the sleeve 42 is provided near the sleeve 42, and a non-magnetic scraping plate 49 is fixed to the upper end of the guide portion 45a, the free end of which follows the circumferential surface of the sleeve 42. It is in contact with the surface. The collection container 45 is detachably attached to the casing 44 of the cleaning device or an appropriate member on the upper part of the copying machine main body. Scraping plate 49 as a means for removing developer from the sleeve surface
may be replaced by other brushes or sleeves of similar construction.

After the transfer of the visible image, when the photoreceptor belt 13 with developer remaining on its surface rotates to the cleaning section, the residual developer, which is magnetic toner, is removed by the magnetic element 43. It is attracted by the moving magnetic field and is transferred from the surface of the belt 13 to the surface of the sleeve 42. The developer transferred to the sleeve surface is rolled clockwise on the sleeve surface by the rotating magnet element 43 and scraped off from the sleeve surface by the scraping plate 49. After getting over the scraping plate 49, the scraped developer does not fall directly toward the bottom 45b of the collection container 45, but instead moves along the guide portion 45a to the magnet element 43.
It moves in the direction of the arrow according to the action of. Guide part 45
The developer moving along the direction a collides with the side portion 45c and is prevented from moving. That is, the developer scraped off from the surface of the sleeve 42 is collected in the collection container 4.
Since the developer is sequentially fed into the deep part of the container 5, the developer can be stored to the full capacity of the container without blocking the entrance of the container.

In the example shown in FIG. 6, the scraping plate 49 and the collection container 45 are separate bodies, but as shown in FIG. 7, this is a sleeve formed by extending one end of the guide portion 45a and 42 may be engaged with the locking portion 42a.

In addition, from the standpoint of improving cleaning performance and protecting the photosensitive surface of the photosensitive belt, some developer or
It is desirable that a certain amount of so-called magnetic brushes be present.

FIG. 8 shows an example of a cleaning device configured to form a magnetic brush on the sleeve surface. A scraping member 50 is stretched between the guide portion 45a of the recovery container 45 and the circumferential surface of the sleeve 42. The scraping member 50 is pivotally attached to the casing 44 by a support shaft 50a. The tip of an adjustment screw 51 is in contact with one side of the scraping member 50,
One end of the member 50 is pressed onto the surface of the sleeve. As best shown in FIG. 9, a protrusion 50b is provided at one end of the scraping member 50, forming a gap G between the scraping member and the sleeve surface.

During cleaning, as shown in FIG. 9, a portion _D1 of the developer D removed from the photoreceptor belt and moving on the sleeve is scraped off by the scraping member 50 and directed to the collection container 45. some of the rest
D ₂ remains on the surface of the sleeve 42 and moves while forming a magnetic brush. The developer D ₂ as a magnetic brush whose brush height has been reduced by the gap G still has sufficient capacity to adhere the developer, and when it comes into contact with the photoreceptor belt 13, the untransferred residual developer is removed. to the sleeve side.

The amount of developer remaining on the photoreceptor belt 13 after the transfer process is extremely small, and the amount of developer transferred onto the sleeve 42 of the cleaning device is commensurate with this amount. For convenience, a large amount of developer D is shown. In the examples shown in FIGS. 7 and 8, the developer that has entered the recovery container 45 from the sleeve 42 is guided deep into the container along the guide portion 45a.

Although this invention has been described above based on the specific embodiments shown in the drawings, the present invention can be implemented within the scope of the spirit of the invention as described in the claims.
It is clear that further species of embodiments are conceivable.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an example of an electrophotographic copying machine to which a cleaning device according to the present invention is applied, FIG. 2 is a longitudinal sectional view of the same, and FIG. 3 is a developing device used in the same copying machine. 4 is a perspective view showing the structure of the magnet element in the cleaning device according to the present invention, FIG. 5 is a front view showing another example of the same magnet element, and FIGS. 6 to 8 are the above FIG. 9 is a vertical sectional view showing different examples of the cleaning device, and FIG. 9 is an enlarged operational view of the main part of the example shown in FIG. 9... Charging/exposure unit, 10... Photoreceptor belt device, 11... Illumination lamp, 12... Imaging optical system, 13... Photoreceptor belt, 14... Charging charger, 15... High voltage generation Device, 21...
Developing device, 28... Cleaning device, 33, 3
4...Shading curtain, 35...Cooling fan, 65...
Flat cable, 42...Nonmagnetic sleeve, 4
3...Magnetic element, 45...Toner collection container, 49
……blade.

Claims (1)

[Claims] 1. A stationary non-magnetic sleeve disposed in contact with or close to the photoreceptor surface, a rotatable magnet element having a plurality of magnetic poles housed in the internal longitudinal direction of the non-magnetic sleeve, and the non-magnetic sleeve. Photoreceptor cleaning comprising means for removing magnetic toner adsorbed to the surface therefrom, and a toner collection container having a non-magnetic wall along the sleeve surface for guiding the removed magnetic toner to flow down. Device.