JPS58186773A - Cleaning device - Google Patents

Abstract

PURPOSE:To execute cleaning without scattering an unsaturated toner even in case when the surface of an image carrier moves at a high speed, and also to collect and reutilize this cleaned toner, in a cleaning device which is used for an electrophotographic light emitting diode (LED) printer being freely contactable and separable to and from the surface of the image carrier. CONSTITUTION:In a process in which a photosensitive drum 1 rotates at a low speed, a covering layer 6a2 of silicon rubber of a rotating sleeve 6a contacts onto a recording body 1a, moves, and slide-rubs and cleans its surface. At the same time, an untransferred toner 7 charged positive is attracted electrostatically to the surface of the covering layer 6a2 by impressing negative bias voltage to a metallic cylinder supporting body 6a1. Subsequently, it is scraped forcibly by a blade 6c and is accumulated, but since the blade 6c is also prepared by a selected material which is charged negative by friction with silicon, electrostatic attracting force is generated, and its electrostatic attracting force is multiplied, and the toner is not scattered. Subsequently, when the process is shifted to an optical write process and the photosensitive drum 1 starts a rotation at a high speed, the rotating sleeve 6a moves by the mechanical mechanism, and the surface of its covering layer 6a2 is separated from the recording body 1a, by which such inconvenience as the untransferred toner is scattered and contaminates the inside of a printing machine is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a leaning device that can freely approach and separate from the surface of an image carrier, and particularly relates to an electrophotographic light emitting diode (LE).
D) It relates to a cleaning device used in a printer.

Generally, an electrophotographic plain paper (PPC) printer that performs optical writing using a light emitting diode (hereinafter referred to as LED) is constructed as shown in FIG. In FIG. 1, reference numeral 1 denotes a photoreceptor drum, and near the circumferential surface of the photoreceptor drum 1 there are sequentially arranged charging devices 2 and 2 along the direction of rotation of the photoreceptor drum. LED! Writing device 3゜Developing device 4. Transfer device5. A cleaning device 6 is provided. Here, LED optical writing device 3
When the LED array 3& is a small LED array composed of about 50 LEDs, the LED array 3& shifts one frame in the axial direction every time the photoreceptor 1 rotates once, as shown in FIG. Writing of all images is completed. Therefore, in a printer with such a configuration, the -order charging is first performed by rotating the photosensitive drum l at low speed, and then the -order charging is performed by rotating the photoreceptor drum l at a low speed.
The photoreceptor drum 1 is rotated at a high speed about 30 times as high as the next charging, and optical writing is performed using the LED array 3m.Finally, the photoreceptor drum 1 is rotated 4 times at a low speed again to perform the remaining development, transfer, and cleaning. As implemented, the desired printing function was achieved through a three-step process. During the optical writing process in which the photoreceptor drum 1 is rotated at high speed, it is necessary to separate devices that are in contact with the photoreceptor drum 1, such as the developing device 4 and the cleaning device 6, from the photoreceptor drum 1 so that they are in a non-contact state. was there. On the other hand, the developing device 4 can deal with this problem by mechanical methods such as increasing the developing gap, but in the cleaning device 6, the sliding portion of the cleaning device 6 is simply mechanically removed from the surface of the photoreceptor drum l. Even if the toner is removed from the printer, the toner accumulated at the time of contact remains on the surface of the photoreceptor drum 1, and due to the high-speed rotation during optical writing, this residual toner scatters all over the printer, contaminating the charging corner wires, LEDs, etc., and causing malfunction. It was the cause.

Particularly in the case of a blade-type cleaning device, the
As shown, the untransferred toner 7 scraped off by the blade 6C does not fall into the tray 6d, but tends to remain on the surface of the photoreceptor 1 at the base where the tip of the blade 6C contacts.

This large amount of residual untransferred toner 7 seriously contaminates the inside of the machine, making it impossible to use a blade-type cleaning device with low equipment costs in an LED printer, and contributing to an increase in the manufacturing cost of the printer. . Another possible countermeasure is to use the developing device as a cleaning device, but in this case, even if the contamination that occurs with blade-type cleaning devices can be avoided, it would be necessary to use an additional photoreceptor drum for the cleaning process. The need for rotation creates a new drawback in that the printing speed becomes slower.

The present invention has been made in view of the above point I, and an object of the present invention is to provide a cleaning device that can freely come into contact with and separate from the surface of an image carrier, which can clean and collect untransferred toner without scattering it by a simple method. With the goal. The non-explosion surface is characterized by the fact that in a cleaning device that is provided so as to be able to come into contact with and separate from the surface of the image carrier and scrub the surface of the image carrier, a non-explosion surface is formed on the outer circumferential surface of a cylindrical support supported by a rotatable number. The present invention has a rotary sleeve on which a coating layer is attached for rubbing and cleaning untransferred toner remaining on the surface of the image carrier, and a holding means for holding the untransferred toner so that it can be adsorbed and removed.

Next, five specific embodiments of the present invention will be described based on the accompanying drawings. FIG. 4 is an explanatory diagram of a cleaning device according to the present invention used in an LED printer, and the other configuration is the same as that of the conventional electrophotographic plain paper copier (PPe) printer of the conventional LED embedding method shown in FIG. . In FIG. 1, reference numeral 1 denotes a photosensitive drum (5) having A112S as a recording medium 1a on its circumferential surface, and is supported for five rotations and rotates in the direction of the arrow. Along the rotation of the photoreceptor drum 1, the vicinity of the surface ξ is the primary charging device 2, as described above. L
ED optical writing device 3° developing device 4. Transfer device5. The cleaning devices 6 are arranged in this order. LED
In the original writing device 3, a small LED array 3& made up of 48 LEDs is connected to an image signal device 3b. The LED blinks, and the light is irradiated onto the recording medium la on the surface of the photoreceptor drum l.

The cleaning device 6 according to the present invention is constructed as shown in FIG. 4 and cleans the surface of the recording medium 1m of the photosensitive drum 1 by rubbing. FIG. 4 - In this figure, a rotating sleeve 6a, which is constructed by forming a coating layer 6ag of silicone rubber on the outer circumferential surface of a metal cylindrical support 611 that is rotatably supported five times, is attached to a photoreceptor drum l. It rotates in the opposite direction to the rotational direction and rubs the 1 m surface (6) of the recording medium of the photosensitive drum 1. Therefore, the surface of the rotating sleeve 6a and the surface of the recording medium 1a of the photosensitive drum 1 rub against each other while moving in the same direction, and the linear velocity of the surface of the rotating sleeve 6a is 1.1 of the linear velocity of the surface of the recording medium 1a. It is set to ~1.3 times. The silicone rubber used in the covering layer 611L2 has a specific resistance value of less than 1O7Ω·6 and is electrically conductive.

A bias application device @6b for applying an appropriate bias voltage is connected to the metal cylindrical support body 6a1 of the rotating sleeve 6&, and one end of this bias application device 6b is grounded. A blade 6C made of a selected material is disposed at a suitable position on the surface of the rotating sleeve 6a, and one end of the blade 6C is in pressure contact with the surface of the coating layer 6m2 of the rotating sleeve 6a. The blade 6c is made of a friction band 1* that is charged to a polarity opposite to that of the toner in order to adsorb the toner.
It is necessary to select materials that have properties.

Next, the operation of the LED printer equipped with the above-mentioned cleaning device according to the present invention will be explained. In FIG. 1, first, a photosensitive drum 1 is charged by a primary charging device 2.
is rotated once to give its surface a positive primary charge. Next, L
The ED optical writing device 3 irradiates light from the LED play 3m in accordance with the image signal sent from the image signal device 3b, and the surface of the recording medium 1a on the circumference of the photoconductor drum l is uniformly charged. So-called optical writing is performed thereon. That is, when the positively charged surface of the recording medium 11 is irradiated with a beam having a wavelength of about 66 On+a by an LED, the electric charge of the portion receiving the source is neutralized and the potential of that portion is lowered.

When the photoreceptor drum l rotates once while being irradiated with light by the LED array 3a, the LED array 3a shifts by one frame in the axial direction of the photoreceptor drum 1, and optical writing is performed on a new portion of the recording medium l&. These operations are repeated to complete the original writing process for the set image size.At this time, the photosensitive drum l is rotated at a rotation speed of 30r, p, m, which is the rotation speed during uniform charging in the previous step. considerably faster than 1
It is rotated at a high speed of about 000r, p, m, and is kept so as not to reduce the overall printing speed. or,
In this case, the electrostatic latent image formed on the recording medium la on the surface of the photoreceptor drum l is a so-called reversal latent image in which the LED corresponding to one image area is turned on by a signal and irradiates light, and the potential of that area decreases. It is a statue. The inverted latent image thus formed on the recording medium 1a is then transferred to the developing device 4! This allows reversal development. At this time, the rotational speed of the photo drum L was set to 30 r, p, m when uniformly charged.

Return to low speed. The developing method uses a normal two-component developing method, and since the toner is developed by reversal, it is positively charged. The developed toner image formed on the recording medium la is then sent to a transfer device &51, where it is transferred onto a transfer paper using a negatively charged corona method, and this transfer paper is sent to a fixing device (not shown) where it is fixed. printing of the image signal is completed. At this time, the untransferred toner remaining on the recording medium 1 is cleaned and removed from the top of the recording medium 1 by a cleaning device 6 disposed on the downstream side, and is prepared for the next new printing cycle. As described above, the print cycle according to this embodiment includes a uniform charging process in which the photoreceptor drum 1 is rotated once at a low speed (9 degrees), and an LED light writing process in which it is rotated a predetermined number of times at a high speed of about 30 to 40 times. The process consists of three steps: 1 rotation at the same low speed as when uniformly charging, development, transfer, and IJ-ning. Therefore, when the optical writing process Il & source drum 1 rotates at high speed, the developing device 4 is in contact with the surface of the photosensitive drum l, that is, the recording medium 1a.
and the cleaning device 6 selectively remove the recording material 1a only at this time.
It becomes necessary to separate from the

In this embodiment, a rotating sleeve type cleaning device according to the present invention shown in FIG. 4 is used. In this cleaning device, during the process in which the photoreceptor drum 1 rotates at the above-mentioned low speed, the silicone rubber coating layer 6a2 of the rotating sleeve 6a moves in the same direction while contacting the recording medium, thereby rubbing the surface of the recording medium. Cleaning. At the same time, a negative bias voltage is applied to the metal cylindrical support 6ai by the bias application device 6b, and the positively charged untransferred toner (lO) 7 is electrostatically attracted to the surface of the coating layer 6az.

The untransferred toner 7 transferred to the surface of the rotating sleeve 6a is forcibly scraped off by the blade 6ci whose one end is in pressure contact with the surface of the coating layer 6a2, and the surface of the blade 6a is forcibly scraped off.
However, since the blade 6c is also made of a selected material that is negatively charged due to friction with the silicone rubber, it generates an electrostatic attraction force, and the electrostatic attraction force is multiplied, so that the coating layer M1 is not dispersed from the 6a2 surface. Then, in the optical writing process, when the photoreceptor drum 1 starts rotating at high speed, the rotating sleeve 6a is moved by a mechanical mechanism, and its coating layer 6a is moved by a mechanical mechanism.
The a2 surface is separated from the recording body la. Therefore, even when the photoreceptor drum 1 rotates at high speed, almost no untransferred toner remains on the surface G of the photoreceptor drum 1, so that the inconvenience of scattering and contaminating the inside of the C printer as in the prior art is eliminated. In addition, rotating sleeve 6&
The untransferred toner 7 transferred to the surface of the silicone rubber coating 6tJt16a2 having an elasticity of Even if the toner is scraped off at the same time, a single layer of toner with a thickness of about 20 to 30 μm is formed because the surface has elasticity. Further, the negative bias voltage to be applied is preferably -50 to -300V.

After repeating the above process and printing the specified number of sheets, switch the bias voltage from negative to positive by one,
Release the blade 6c from the rotating sleeve 6a. Then, the untransferred toner 7 adhering to the rotating sleeve 6a is transferred backwards to the recording medium 1 and upwardly. The transferred untransferred toner 7 is then carried to the area where the developing device 4 is disposed according to the rotation speed of the photosensitive drum 1, and the operating conditions of the developing device 4 such as the developing bias voltage are adjusted here. is returned into the developing device 4.

Next, another embodiment of the cleaning device according to the present invention will be described. The LED printer in the above embodiment is as follows:
Resin and carbon as toner.

The main component is dye and a mixture of these is used.

However, the LED printer of this example uses a so-called magnetic toner made by adding magnetic particles as components in addition to resin, carbon, and dye as a toner, and uses two-component development in which this is mixed with a carrier for development. This is the method to do it. In this example, a magnetic cleaning device according to the present invention is used in which an appropriate number of magnets 8 are arranged as shown in FIG.

In FIG. 5, the rotating sleeve 6& is constructed by adhering a coating layer 5B of silicone rubber on the circumferential surface of a metal cylindrical support 61, as in the previous embodiment, and this cylindrical support Inside 6al, four magnets are arranged in approximately equal numbers near the inner circumferential surface thereof. A four-way bias applying device 6b is connected to the metal cylindrical support body 6ai i inside the rotating sleeve 6a, as in the previous embodiment, and applies a bias voltage to the rotating sleeve 6&. The other configurations and mechanisms are substantially the same as those of the previous embodiment.

In this example, the untransferred magnetic toner (13) remaining on the surface of the photosensitive drum l, which is the recording medium of the printer, is disposed inside when it is rubbed and cleaned by the one-turn sleeve 6&. The magnet 8 is attracted by the magnetic force j of the magnet 8, so it is easily transferred onto the coating layer 6a2 of the rotating sleeve 6a.The combination of this magnetic force and the sliding function of the rotating sleeve 6& is enough to clean the recording medium 1a. Therefore, in this example, it is not necessary to apply a bias voltage during cleaning.After printing a predetermined number of sheets, as in the previous example, a bias voltage of the same polarity as the toner charging polarity is applied. is applied to the rotating sleeve 6a by the bias applying device 6bi. Through this operation, the untransferred toner 7' that has adhered and accumulated on the coating layer 6a2 of the rotating sleeve 6a is transferred onto the recording medium 1a and roughly transported to the developing section. The magnet 8 is returned to the developing device and reused as developing toner.
Even if the magnetic force of
It can be reduced to &.

As described in detail above, according to the present invention, even when the surface of the image carrier moves at high speed, the untransferred toner (14) can be cleaned without scattering the toner, and the cleaned toner can be collected. It is possible to obtain a system cleaning device that can be reused and can come into contact with and separate from the surface of the image carrier.Therefore, it is possible to prevent the inside of the equipment in which this cleaning device is installed from being contaminated by toner. It improves the durability of the equipment. Also, economical efficiency is improved because the toner is reused with a simple mechanism. In addition, the image carrier can be moved at high speed, increasing the operating speed of the equipment. However, the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing the concept of an LED photo printer, Fig. 2 is an explanatory diagram showing the operational relationship between the photoreceptor drum and the LED array, Fig. 3 is an explanatory diagram of a conventional blade cleaning device, and Fig. The figure is a schematic explanatory diagram showing one embodiment of the cleaning device according to the present invention when used in an LED printer, and FIG.
FIG. 6 is an explanatory diagram showing another embodiment when used in an ED printer. (Explanation of symbols) l: Photosensitive drum 3: LED optical writing device 6a: Rotating sleeve 6b: Bias device 6c Ni blade 8: Magnet patent applicant Ricoh Co., Ltd. - Fig. 1 ■ Fig. 2 ↓ Fig. 3 Dan Figure 4

Claims (1)

[Scope of Claims] (2) In a cleaning device that is provided so as to be able to come into contact with and separate from the surface of an image carrier and to rub and clean the surface of the image carrier, the above-mentioned cleaning device is provided on the outer circumferential surface of a cylindrical support that is rotatably supported. 1. A cleaning device comprising: a rotating sleeve having a coating layer attached thereon for rubbing and cleaning untransferred toner remaining on the surface of an image bearing member; and a holding means for holding the untransferred toner so as to be able to be adsorbed and removed. 2. The cleaning device according to item 1 above, wherein the coating layer is made of silicone rubber. 3. In the above item 1, the holding means applies a bias voltage to the rotating sleeve and a blade formed of a selected material having triboelectric charging characteristics that are charged to a polarity opposite to that of the untransferred toner. A 4v9 cleaning device comprising a biasing means. 4. The cleaning device according to item 1 above, wherein the holding means is comprised of an appropriate number of magnets disposed inside the rotating sleeve and bias means for applying a bias voltage to the rotating sleeve. Device.