JPS614092A - Cleaning device - Google Patents

Abstract

PURPOSE:To permit satisfactory cleaning of foreign matter by supplying a toner to an image carrying body according to the humidity detected near said body and rubbing the toner to the image carrying body. CONSTITUTION:The scraper member 6 of a cleaning device 2 contacts with a magnet roller 4 via a solenoid when the foreign matter on a photosensitive body 1 which is the image carrying body absorbs the moisture in air and when the humidity detected near the photosensitive body attains a prescribed value such as 70% or above. The magnetic toner is then supplied to the body 1 so that said body is rubbed by the toner. The foreign matter is thus satisfactorily cleaned.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a printer that utilizes an electrostatic photographic process, and a cleaning apparatus therefor.

The process involves forming a transferable toner image on a moving image carrier, transferring the toner image to a transfer material mainly made of paper, and removing residual toner on the surface of the image carrier that did not contribute to the transfer. As a residual toner removing means in a well-known image forming apparatus, a cleaning blade made of an elastic material such as urethane rubber has been widely used because of its excellent toner removing function.

However, the substances that adhere to the surface of the image carrier are not only toner, but also fine paper particles generated from the transfer paper, dust in the air, precipitates such as rosin and talc deposited from the transfer paper, and high pressure inside the image forming device. There are various foreign substances such as corona products caused by the presence of the parts, and although cleaning blades have an excellent function in removing toner, they are not necessarily effective against the various foreign substances mentioned above.

When such foreign matter adheres to the surface of the image carrier, it absorbs moisture in the air and lowers the resistance, which may cause image deletion.

In order to avoid such inconveniences, it has been proposed to supply an abrasive to the surface of the image carrier in order to remove the above-mentioned foreign matter from the surface of the image carrier, but the effect is unstable and unsatisfactory. Not getting the desired results.

In addition, the present applicant has proposed that in a device equipped with a magnetic roller or the like close to the image carrier to capture and transport the r-toner removed from the surface of the image carrier, a large amount of toner is accumulated in a space adjacent to both of the rollers. They have proposed a method in which the surface of the image carrier is rubbed with this toner to remove foreign matter. Although these devices have an excellent foreign matter removal function, they accumulate a large amount of toner, which may scatter outside the cleaning device and contaminate other parts, adversely affect image formation, and cause other problems such as Since the toner is rubbed onto the image bearing member, the burden of cleaning becomes heavy, and there is a risk of poor cleaning.

The present invention was made to deal with such a situation, and by detecting the humidity near the surface of the image carrier,
Only when this reaches a preset humidity, a large amount of toner is supplied to the surface of the image carrier and the surface is rubbed to remove the aforementioned foreign matter, making it possible to consistently obtain good images at all times. The purpose is to obtain a device.

(2) Structure of the Invention In order to achieve the above-mentioned object, the present invention provides a cleaning device with a scraper member that approaches and separates from a magnetic roller that captures and conveys scraped toner, etc. A sensor for detecting humidity is disposed near the body, and only when the humidity near the image carrier reaches a set value, the above-mentioned scraper member is brought close to the toner capture and conveyance means to accumulate toner in the partial space. The surface of the image carrier is sufficiently rubbed with this toner to remove foreign substances such as corona products, thereby minimizing the amount of rubbing of the image carrier by the toner.

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

FIG. 1 is a side view of essential parts showing a case where a cleaning device according to the present invention is applied to a copying machine using a rotating cylindrical photoreceptor. A cleaning device 2 is disposed at a predetermined position near the photoreceptor 1 and extends parallel to the axial direction of the photoreceptor, and magnetic toner is used as the toner.

Around the photoreceptor, a means for uniformly charging the photoconductive layer on the surface of the photoreceptor, a means for irradiating a light image onto the photoconductor to form an electrostatic latent image, a developing means for visualizing the latent image, and a means for uniformly charging the photoconductive layer on the surface of the photoreceptor; Although means for transferring the toner image onto the transfer material are provided, they are not directly related to the present invention, and therefore their explanation will be omitted.

The cleaning device 2 includes a cleaning blade 3.
is disposed, and its edge presses against the surface of the photoreceptor to scrape off the toner that has adhered to the photoreceptor without contributing to transfer in the transfer means when it reaches the blade. The scraped toner is captured by the magnetic roller 4, and as the magnetic roller rotates, it reaches a door toner storage section in the cleaning device, and is further discharged from the cleaning device by the screen conveyor 5 as necessary. do.

In such a leaning device, according to the present invention, a scraper member 6 that approaches and separates from the magnetic roller 4 is disposed inside the device.

As shown in FIG. 2, the scraper member 6 consists of a plate member 6b having an appropriate number of openings 6C formed therein and a support rod 6a attached to the plate member 6b, and is installed in the cleaning device.
It is rotatable at that position, and can selectively take a position in contact with the magnet roller, as shown by a solid line in FIG. 1, and a position away from it, as shown in a dotted line.

FIG. 3 schematically shows the means for swinging the scraper member 6 as described above, in which a spring 7 is attached to one side of the wire 8 wound around the pulley 9 attached to the end of the support rod 6a. Thus, the plate body 6b is always rotated counterclockwise in the drawing, and the other end of the wire is attached to the solenoid SQL. Therefore, by energizing the solenoid, the wire 8 can be pulled against the action of the spring 7 to rotate the pulley 9 and therefore the scraper member 6 clockwise in the drawing.

FIG. 3b shows a configuration in which the scraper can be displaced in stages, and with this configuration, the amount of toner can be further suitably adjusted.

In this device, the scraper 6 is supported by a swinging fulcrum 6a, and a cam 10 is attached to a roller 12 attached to one end of the scraper 6.
are in contact with each other. The cam 10 is rotatable about an axis lla, and a one-way clutch 11 is arranged on the same axis, and this one-way clutch is operated by a lever L.

A solenoid SQL is attached to the free end of the lever.
One-way clutch is activated by energizing and de-energizing this solenoid.
Therefore, since the cam 10 can be rotated in steps, the solenoid can be energized and deenergized several times to determine a plurality of scraper positions according to the cam surface position.

For example, MgCr2O4 and T
A ceramic humidity sensor made of a porous sintered body of iO2 is used, and this is placed at a suitable location near the surface of the photoreceptor (
(not shown), and its output is input to the CPU. The CPU processes the output of the humidity sensor and sets the set humidity, for example RH7.
If it is 0% or more, the solenoid of the scraper member 6 is turned on, the scraper member is brought close to the magnetic roller 4, and the toner that is conveyed on the surface thereof is accumulated on the relevant portion.
The surface of the photoreceptor is rubbed by the accumulated toner to remove foreign matter adhering thereto. When the humidity drops below 70 degrees, the solenoid is turned off, and the scraper member 6 separates from the roller 4 to convey the toner to a storage section in the cleaning device, and the photoreceptor is not rubbed by the toner.

FIG. 4 shows a flowchart showing the above operation.

In the above case, the solenoid is in the on state from the front rotation of the photoconductor to the rear rotation after copying. However, depending on the output value of the humidity sensor, the on time of the solenoid can be varied using a timer. I can do it. FIG. 5 is a graph showing a case where the humidity value is divided into predetermined ranges and the on-time of the solenoid is changed stepwise, and FIG. 6 is a graph showing a case where the on-time is continuously controlled.

FIG. 7 shows a case where the amount of stored toner is changed by changing the position of the scraper member depending on the humidity. For example, in a cleaning device as shown in Figure 1, the distance between the magnet roller 4 and the inner surface of the cleaning device housing in the vicinity thereof is 21+OL+1, and the distance p1 between the magnet roller and the photoreceptor is 3. Then, when the scraper member 6 is away from the roller, the height of the magnetic brush is approximately 2.5 cylinders in the spaced part, and the toner conveyed by the magnetic roller does not come into contact with the photoreceptor. . By moving the scraper member 6 closer to the magnet roller and changing the distance corresponding to the numbers in FIG. Foreign matter can be removed more strongly.

(If the humidity setting value mentioned above is below 70 degrees,
By configuring the structure so that the toner rubs against the photoconductor as in the above example, a cleaning device such as a cleaning blade can transfer a larger amount of the toner, which has a high specific charge and is easily adsorbed to the photoconductor in low humidity conditions. It is preferable to increase the cleaning load by feeding the cleaning material to the desired location to avoid situations such as poor cleaning.

(3) Effects of the Invention The present invention has the above-described structure and operation, and the toner is rubbed onto the surface of the image carrier only when the area around the image carrier is in a high humidity atmosphere. , it is possible to reliably prevent foreign matter such as precipitates from transfer paper and corona products from having a negative effect on image formation by lowering the resistance of the surface of the image carrier, and also to prevent foreign matter such as deposits from transfer paper and corona products from adversely affecting image formation. Sometimes, since a large amount of toner is not supplied, a sufficient rubbing effect can be obtained with a small amount of toner overall, which may damage the image bearing member or cause toner to scatter and stain various parts of the image forming apparatus. It is possible to avoid a situation in which a cleaning device such as a cleaning blade or the like is subjected to an excessive load, resulting in poor cleaning, and it is possible to stably obtain high-quality images over a long period of time.

[Brief explanation of drawings]

Fig. 1 is a side view of essential parts showing an embodiment of the cleaning device according to the present invention, Fig. 2 is a partial plan view showing the configuration of the scraper member, and Fig. 3a is an explanatory diagram showing an example of a mechanism for operating the scraper member. , FIG. 3b is an explanatory diagram showing another example of a mechanism for operating the scraper member, FIG. 4 is a flowchart showing the operating mode of the cleaning device according to the present invention, and FIGS. 5, 6, and 7 are diagrams showing humidity and It is a graph showing the relationship with the operation of the scraper. 1... Photoreceptor, 2... Cleaning device, 3...
Cleaning blade, 4... Magnet roller, 6
...Scraper member.

Claims (1)

[Claims] A humidity detection means for detecting the humidity near the surface of the image carrier, and a cleaning device disposed close to the surface of the image carrier are provided, and the device applies toner to the surface of the image carrier according to the detected humidity set by the humidity detection means. A cleaning device comprising a means for supplying and rubbing the same.