JPH03212676A - Cleaning device - Google Patents

Abstract

PURPOSE:To separate toner adhering to the back surface of a blade, to remove it by next copying and to eliminate offset by providing a magnet on the surface of a photosensitive body and in the vicinity of the edge of the blade and changing magnetic field when an image is not formed. CONSTITUTION:When copying is started, the blade 17 comes in contact with the surface 10 of the photosensitive body 1 and the photosensitive body 1 rotates in a direction A. Next, magnetic rollers 22 and 23 rotate in a direction E by a motor 29 so as to change the magnetic field for the toner adhering to the back surface of the blade 17 and act to separate the toner from the blade with Lorentz's force and attract it to the surface 10. Even when the motor 29 is stopped, the toner rotates in a state where it adheres to the surface 10 with image-force or van der Waals force, etc., and reaches the blade 17. Then, it is peeled and removed by an edge 18 and drops in a housing 11. Thereafter, the photosensitive body 1 performs a copying action and the blade is separated from the surface 10 to prepare for next copying simultaneously with finishing and stopping the copying action.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device installed in an electrostatographic copying machine or the like.

[Conventional technology]

For example, in an electrostatographic copying machine, an exposure device exposes the surface of a rotating drum-shaped photoreceptor to form an electrostatic latent image, and this electrostatic latent image is turned into a specific polarity by frictional charging. After developing with charged non-magnetic toner and transferring the toner image formed on the surface of the photoreceptor to copy paper using a transfer device, the toner remaining on the surface of the photoreceptor is removed using a cleaning device. I try to do that.

FIG. 10 shows an example of a conventional cleaning device of this type. In the same figure, 51 is a photoreceptor that rotates in the direction of arrow a around a rotation axis (not shown), and 52 is a surface 5 of the photoreceptor 51.
3, a cleaning device 54 is provided over almost the entire width of the photoconductor l in the axial direction; 54 is a cleaning device 5;
This is the second housing.

A rotation shaft 5 is provided inside the housing 54 in parallel with the rotation shaft.
5, and the second rotating shaft 55 is configured to be able to rotate in the directions of arrows b-c by means of a solenoid (not shown). Reference numeral 56 denotes a blade attachment member fixed to the rotating shaft 55, and this blade attachment member 56 is provided with a peeling blade 57 made of a suitable elastic material such as urethane rubber. When the solenoid is on, the blade edge on the free end side of this blade 57 comes into contact with the photoreceptor surface 53 to peel off and remove the toner T remaining on the photoreceptor surface 53, and when the solenoid is off, is configured to be spaced apart from the photoreceptor surface 53 by a predetermined distance.

A blade 59 is provided upstream of the blade 57 in the rotational direction A of the photoreceptor 51, and is made of a sheet having appropriate elasticity, such as a thermoplastic sheet, and its free end 60 is a blade. The receiver stops the toner T peeled off by the blade 57 so as not to scatter it outside the housing 54, and the receiver stops the stopped toner T. It slides down in the direction of the toner transport body 61.

Reference numeral 61 denotes a toner transporting body having a helical rotating shaft provided at the bottom of the housing 54 in parallel with the rotating shaft 55. The toner transporting body 61 rotates, for example, in the direction of arrow d, and transfers the toner T collected from the photoreceptor surface 53 to toner (not shown). It is transferred to the collection container side.

According to the cleaning device 52 configured in this way, during the copying operation, the toner T remaining on the photoreceptor surface 53 after transfer is peeled off by the blade edge 58 that is in contact with the photoreceptor surface 53. The receiver passes through the blade 59 and reaches the toner transport body 61, and is further sent toward a toner collection container (not shown) by the toner transport body 61 and collected.

Note that the blade edge 58 of the blade 57 is brought into contact with the photoreceptor surface 53 only during a copying operation, and the blade edge 58 is separated from the photoreceptor surface 53 during a non-copying operation. This is because if the blade edge 58 is always kept in contact with the photoreceptor surface 53, the photoreceptor surface 53 will become distorted, and as a result, a clear image will not be obtained, or the blade 57 will deform. This is because the toner T on the photoreceptor surface 53 cannot be peeled off and removed.

[Problem to be solved by the invention]

By the way, in the cleaning device 52 using the blade 57, as the number of copies increases, the toner T removed from the photoreceptor surface 53 is deposited on the blade edge 58 as indicated by the symbol e, as shown in FIG. The toner T is moved toward the side end portion, and the toner T is eventually dragged along the photoreceptor surface 53 to the side end portion e and the housing 5.
The particles pass through the gap f between the blade 57 and the back surface of both ends e of the blade 57, and are deposited as shown in FIG.

The toner T deposited on the back side of the blade 57 in this way causes the following situation. That is, the toner T is deposited near the blade edge 58 due to impact when the blade 57 moves away from the photoreceptor surface 53 after continuous copying, or when it comes into contact with the photoreceptor surface 53 during a copying operation. Move to. Then, when the blade 57 comes into contact with the photoreceptor surface 53 during the first copy performed next after a certain continuous copy is completed, the photoreceptor 51 is charged by the main charger. The electrostatic latent image at that time is reproduced by the toner T adhering to the blade edge 58, and this appears as a so-called offset during the next first copy, resulting in double copying.

In other words, if the toner T is deposited on the back side of the blade 57, an offset may occur and a clear image may not be obtained.

The present invention has been made with the above-mentioned considerations in mind, and its purpose is to reliably remove toner that wraps around the back surface of the blade before the next copy, thereby causing offset. Our goal is to provide a cleaning device that never fails.

[Means to solve the problem]

In order to achieve the above object, the cleaning device according to the present invention provides a magnet near the surface of the photoreceptor and near the edge of the blade, and applies a magnetic field from the magnet to the back surface of the blade when not forming an image. By applying a Lorentz force to the toner, the toner is released from the blade, and
The present invention is characterized in that the blade is brought into contact with the surface of the photoreceptor and the photoreceptor is rotated in this state so that the toner adhering to the surface of the photoreceptor is peeled off and removed by the blade.

[Effect]

In the cleaning device according to the present invention having the above-mentioned characteristic configuration, for example, just before starting copying, when the magnet is rotated and its magnetic field is changed with respect to the toner adhered to the back surface of the blade, the Lorentz A force is applied, and this Lorentz force causes the toner to be released from the blade and adhere to the surface of the photoreceptor. The toner adhering to the surface of the photoreceptor is then peeled off and removed by the blade by rotating the photoreceptor while the blade is in contact with the surface of the photoreceptor.

〔Example〕

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

1 to 5 show an embodiment of the present invention.

First, FIG. 3 shows the main parts of an electrostatographic copying machine incorporating a cleaning device according to the present invention. Charger 2. Developing device 3, transfer device 4. Paper separation device5. A cleaning device 6 (details of its configuration will be described later), a static eliminator 7, and the like are provided. Reference numeral 8 denotes a paper conveyance path for conveying copy paper fed from a paper feeder (not shown) toward the photoreceptor 1, and 9 conveys light from an exposure device (not shown) to the surface of the photoreceptor 10.
It is a mirror that reflects the light.

The configuration of the cleaning device 6 will be explained with reference to FIGS. 1 and 2. 11 is a housing;
A rotation shaft 13 is provided inside the photoreceptor l in parallel with the rotation shaft 12 of the photoreceptor l.
is the provision. An output portion 15 of a solenoid 14 is connected to one end of the rotation shaft 13, so that the output portion 15 of a solenoid 14 can be turned in the direction of arrow B-C by turning the solenoid 14 on or off. Reference numeral 16 denotes a blade attachment member fixed to the rotating shaft 13, and the blade attachment member 16 is provided with a peeling blade 17 made of a suitable elastic material such as urethane rubber. When the solenoid 14 is on, the blade edge 18 on the free end side of this blade 17 comes into contact with the photoreceptor surface 10 to peel off and remove the toner T remaining on the photoreceptor surface 10, and when the solenoid 14 is off, is configured to be spaced apart from the photoreceptor surface 10 by a predetermined distance.

Further, a blade 19 is provided in the housing 11 on the upstream side of the blade 17 in the rotational direction A of the photoreceptor 1 . In this receiver, the blade 19 is made of a sheet having appropriate elasticity, such as a thermoplastic sheet, and is arranged so that its free end 20 abuts against the photoreceptor surface 10 with a predetermined contact pressure. Blade 17
The receiver is stopped so as not to scatter the toner T peeled off outside the housing ll, and this receiver is used to prevent the toner T that has been peeled off from
The toner transport body 21 is configured to slide down toward the toner transport body 21.

Further, at the bottom of the housing 11, a toner transporting body 21 is provided parallel to the rotation shaft 13 and has a helical rotation shaft.
For example, by rotating in the direction of the arrow, the toner T collected from the photoreceptor surface 10 is transferred to a toner collection container (not shown).

The configuration up to this point is no different from conventional cleaning devices of this type.

Now, according to the present invention, 22 and 23 are roller-shaped magnets (hereinafter referred to as magnet rollers) made of permanent magnets, which are provided on the photoconductor surface IO and near both left and right ends in the vicinity of the blade edge 18. It is held so that it can rotate inside. That is, photoreceptor 1
A bracket 25 is attached to the rotary shaft cover 24 which has a square cross-sectional shape.
26 is installed upright, and magnetic rollers 2 are attached to both left and right ends of the shaft 27 which is inserted through the through hole opened at 25 and 26.
2.23 is the attachment, and the shaft 27 is connected to the transmission mechanism 2.
8 and is connected to a motor 29 which rotates reversibly. The N and S poles of each magnet roller 22, 23 are set so that the direction of the magnetic field is in the direction indicated by the arrow in FIG.

The operation of the cleaning device 6 having the above configuration will now be described with reference to FIGS. 4 and 5.

First, when a copy start button (not shown) is turned on (step Sl), the blade 17 comes into contact with the photoreceptor surface lO (step 32), and the photoreceptor 1 begins to rotate in the direction indicated by arrow A in FIG. (Step S3).

Next, the motor 29 is turned on and rotates in a predetermined direction, causing the shaft 27 to rotate, thereby causing the magnet rollers 22, 23 to begin rotating in the direction shown by arrow E in FIG. 1 (step S4). Since the toner T adhering to the back surface of the magnet roller 22 can be regarded as charged particles (for example, negatively charged particles),
．． By the rotation of 23, the magnetic field for the toner T changes,
Furthermore, in this case, the Lorentz force acts to release the toner T from the blade 17 and draw it toward the photoreceptor surface 10, so that the toner T released from the blade 17 adheres to the photoreceptor surface 10 (fifth (see figure),
Note that in FIG. 5, T indicates toner attached to the surface 10 of the photoreceptor.

Then, the motor 29 is turned off, and the magnet roller 22
23 stops rotating (step S5), the Lorentz force disappears, but the toner T attached to the photoreceptor surface IO
Since mirror image force, van der Waals force, etc. act on IO, it is not released from the photoreceptor surface IO. The toner T adhering to the photoreceptor surface 10 rotates with the photoreceptor 1 rotating in the direction of arrow A, reaches the blade 17, and is peeled off and removed by the blade edge 18 in contact with the photoreceptor surface 10 (step S6. (see Figure 5), housing 1
Fall within 1. Note that in FIG. 5, T indicates the toner that has rotated about one time while being attached to the photoreceptor surface IO.

Thereafter, the photoreceptor 1 rotates in the direction of the arrow A with the blade 17 in contact with the photoreceptor surface 10, a copying operation is started (step S7), and after a predetermined copy is performed,
When the copying operation is completed (step S8), it stops.
At this time, the blade 17 is also spaced apart from the photoreceptor surface 10 (step S9) and stands by in preparation for the next copy.

As can be understood from the above explanation, the toner T attached to the photoreceptor surface 10 by Lorentz force is held on the photoreceptor surface 10 by mirror image force and van der Waals force, but as shown in FIG. After turning on the copy start button, the photoreceptor L is charged (step 510) until the magnet rollers 22 and 23 are rotated, so that the toner T released from the blade 17 is transferred to the photoreceptor surface 1.
The value may be held more reliably by setting the value to 0.

The present invention is not limited to the embodiments described above, but can be implemented in various ways.

That is, the magnet rollers 22 and 23 may be provided outside the photoreceptor 1, as shown in FIG.
In this case as well, the photoconductor surface 10 and the blade edge 1
Needless to say, it is preferable to provide the magnetic roller 22.8 near both left and right ends of the magnetic roller 22.8.
In No. 23, either the direction of the magnetic field or the direction of rotation must be reversed from that of the above embodiment.

In each of the above embodiments, the magnetic rollers 22, 23
N so that the direction of the magnetic field is in the longitudinal direction of the blade 17.
However, as shown in FIGS. 7 and 8, the N and S poles are arranged and attached to the back of the blade 17 by rotating them respectively. The toner T may be released from the blade 17 and vibrated in the longitudinal direction.

Furthermore, in each of the above embodiments, the magnet roller 2
2.23 is provided on the downstream side of the blade 17 in the rotational direction of the photoreceptor l, but it may be provided on the upstream side.
It is sufficient that the Lorentz force is applied to the toner T adhering to the back surface of the blade 17 at both left and right ends thereof.

Furthermore, the toner T may be removed immediately after a predetermined copying operation is completed, and the flow of the operation in that case is as shown in FIG. 9. Description of this flowchart will be omitted.

Furthermore, the shapes of the magnets 22 and 23 can be set arbitrarily. Alternatively, it may be constructed from an electromagnet.

〔Effect of the invention〕

As explained above, in the present invention, the Lorentz force is applied to the toner attached to the back surface of the blade by rotating the magnet and changing the magnetic field immediately before the start of a predetermined copy or immediately after the end of the copy. At the same time, the toner is released from the blade, and the photoconductor is rotated with the blade in contact with the photoconductor surface, and the toner adhering to the photoconductor surface is peeled off and removed by the blade. Even if toner gets around to the back surface of the blade during operation and adheres to the back surface of the blade, it can be released from the blade and fall into the housing. Therefore, offset caused by residual toner, which has been a problem in the past, can be eliminated, and it can greatly contribute to the formation of clear, high-quality images.

Furthermore, since toner adhesion or accumulation on the back surface of the blade can be eliminated, toner does not stain the main charger and static elimination lamp, and the paper is not soiled due to toner falling into the paper conveyance path.

[Brief explanation of drawings]

1 to 5 show one embodiment of the present invention, FIG. 1 is a perspective view showing the main parts of the cleaning device according to the present invention, and FIG.
The figure is a cross-sectional view thereof, FIG. 3 is a longitudinal cross-sectional view showing the main parts of an electrostatographic copying machine incorporating the cleaning device, FIG. 4 is a flow chart for explaining the operation, and FIG. 5 is for explaining the operation. FIG. FIGS. 6 to 8 are partially enlarged views showing other embodiments. FIG. 9 is a flowchart according to another embodiment. 10 to 12 show the prior art, FIG. 10 is a sectional view showing a conventional cleaning device, FIG. 11 is a developed sectional view showing the main parts thereof, and FIG. 12 is a perspective view. 1... Photoreceptor, 6... Cleaning device, 10...
・Photoreceptor surface, 17...Blade, 18...Blade edge, 2223...Magnet, T, T,,T,
...Toner applicant: Sanda Kogyo Co., Ltd. Agent: Patent attorney Hideo Fujimoto Fig. 5, 12 2... Toner: Fig. 6, Fig. 7, Fig. 8, Fig. 10, Fig. 11, Fig. 12

Claims (1)

[Claims] A cleaning device in which a plate for peeling off and removing residual toner on the surface of a photoreceptor can be freely switched between a state in which it comes into contact with the surface of the photoreceptor during image formation and a state in which it is separated from the surface of the photoreceptor during non-image formation. In this method, a magnet is provided near the surface of the photoreceptor and near the edge of the plate, and when an image is not formed, a Lorentz force is applied to the toner attached to the back surface of the blade by changing the magnetic field generated by the magnet. The plate is brought into contact with the surface of the photoreceptor, and the photoreceptor is rotated in this state so that the toner adhering to the surface of the photoreceptor is peeled off and removed by the plate. A cleaning device characterized by: