JPH04482A - Cleaning device for image forming device - Google Patents

Abstract

PURPOSE:To effectively utilize the space of a storage part without providing a special toner moving means by forming a curved surface for guiding toner which is accumulated on an inner wall surface above a press-contact edge where a cleaning blade presscontacts with an image carrier. CONSTITUTION:On the inner side surface at a part where a supporting member 2 for the cleaning blade 3 of a casing 4 is attached to the casing, the curved surface 4a having proper curvature is formed to be recessed with respect to the inner side of the casing. Thus, the residual toner which is not transferred to a transfer material at a transfer part and remains on the surface of an image carrier 1 is scraped to be dropped by the blade 3, then it grows grdually in the vicinity of the dropped part and reaches the curved surface 4a. It is guided by the curved surface, smoothly moves to the deep side of the casing in the direction as shown by the arrow (e), breaks loose without flocculating, and is stored in the deep side. Therefore, the space is effectively utilized and the capacity of storing the toner is increased.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and particularly to a cleaning device for the same. be.

(Prior Art and Problems to be Solved) The process of superimposing a transferable toner image formed on the surface of a moving image carrier on a transfer material such as paper and electrostatically transferring the toner image to the transfer material ( In a well-known image forming apparatus that transfers residual toner that does not transfer to the transfer material during transfer,
It is necessary to sufficiently remove it from the image carrier each time.

Various methods have been proposed to remove residual toner, including one edge of a cleaning blade made of an elastic material such as urethane rubber that is pressed against the surface of the image carrier to remove residual toner. It is well known that devices that scrape and remove toner are widely used because they have a simple construction, are compact, and have an excellent toner removal function.

FIG. 4 shows an example of a typical configuration of such a leaning device, and the configuration and operation will be briefly described using this figure.

A cleaning device C is disposed close to and parallel to a cylindrical image carrier 1 that extends perpendicularly to the plane of the paper and rotates in the direction of the arrow in the figure.

The cleaning device C has an opening formed on the side facing the image carrier, and a support member 2 attached to the edge of the opening.
A cleaning blade 3 supported by is in pressure contact with the image carrier 1 .

Some of the toner that has not been transferred to the transfer material at an unspecified transfer site reaches the edge portion of the cleaning blade 3 as the image carrier 1 rotates, where it is scraped off from the image carrier by the cleaning blade 3. This toner is guided by the scooping sheet 5 and sequentially stored in the toner storage section in the casing 4.

In such a device, in order to prevent collected toner from accumulating near the scooping sheet 5, the toner storage space can be fully utilized by moving the toner to the back of the toner storage section using, for example, a rotating blade or the like. It has been previously proposed to do so.

However, in recent years, cartridges have become widely used, in which an image carrier and some components arranged around it, such as a wide charger, a developing device, and a cleaning device, are integrated into a cartridge. Since this type of image forming apparatus is intended to be small and low-cost, it is common to have a configuration in which means such as the above-mentioned rotating blades are removed.

In such a case, in order to increase the collected toner capacity, the casing 4 of the cleaning device C should be extended downward or to the left in FIG.
Since there is a conveyance path in that part for conveying the transferred transfer material to the fixing site, it can be said that this is practically impossible in a cartridge type image forming apparatus where compactness is the top priority.

Furthermore, extending the casing 4 to the left increases the depth, but if there is no means to send the collected toner deep into the casing, such as the aforementioned blade, the toner will accumulate near the blade. This results in a problem that even if the capacity of the casing is increased, it cannot be utilized.

This will be further explained with reference to FIG. 4 and subsequent figures.

As shown in FIG. 4, if the point at which the cleaning blade 3 comes into contact with the surface of the image carrier is i, then this point is at an angle greater than the horizontal line passing through the center g of the image carrier 1 when the image carrier is traveling. By configuring the blade 3 so that it is on the downstream side when viewed in the direction, the permissible setting range for the direction of the blade 3 is increased, and as a result, the vertical length of the casing and (on the image carrier side) must be reduced. It is normal to avoid this.

However, with such a configuration, the toner scraped off from the surface of the image carrier is scraped off by subsequent toner.
Since the toner is subjected to a pressing action in the tangential direction at point i, it tends to solidify in this area, and as a result, the toner gradually grows in the vicinity of the inlet of the cleaning device, as shown by the arrow in FIG. , and finally reaches the top of the casing, as shown in FIG.

In this state, the toner continues to be subjected to the force in the direction of arrow C, so some of the toner falls in the direction of arrow d, but the other part tends to further assimilate, and from then on The toner scraped off by the blade cannot enter the cleaning device (and slips through the blade, resulting in poor cleaning).

Such a situation is extremely inconvenient in a cartridge-type image forming apparatus because the life of the cartridge is unduly shortened due to a malfunction of the cleaning device.

The present invention has been made in order to cope with such a situation, and it is possible to completely utilize the collected toner storage section in a cleaning device using a cleaning blade without causing the above-mentioned inconveniences. The purpose of this invention is to provide a cleaning device, which is particularly advantageous in the case of a cartridge type that does not have a separate waste toner container for guiding and storing waste toner.

(2) Structure of the invention (technical means for solving the problem, its effect) In order to achieve the above object, the present invention provides a cleaning device equipped with a cleaning blade that presses against the surface of an image carrier. Above the edge of pressure contact with the body,
This device is characterized by forming a curved surface on the inner wall surface of the cleaning device casing to guide the toner that is collected and naturally deposited to the back side.

With this configuration, the space of the toner storage section of the cleaning device can be effectively used without providing a special toner moving means, etc., and the toner storage capacity of the cleaning device can be increased. .

(Description of Embodiments) FIG. 1 is a side sectional view of a process cartridge showing an embodiment in which the present invention is applied to a cartridge-type image forming apparatus. An image carrier 1 having an axis in the vertical direction and rotating in the direction of arrow a, a charging device 7, a developing device 6, and a cleaning device C are arranged, and these can be attached to and removed from the main body of the image forming apparatus as a whole. It can be worn freely.

Among the above, cleaning device C will be explained as follows.
One edge of the free end of the cleaning blade 3, which is integrally formed with the support member 2 attached to the cleaning device, is in pressure contact with the surface of the image carrier.

The contact point i of the cleaning blade 3 on the image carrier is at an angle h, 3° in the illustrated case, above the horizontal line passing through the center g of the image carrier.

The support member 2 is approximately L-shaped and has a cleaning blade 3 attached to one leg and a cleaning blade 3 attached to the other leg to the casing of the cleaning device.

When residual toner that is not transferred to the transfer material at a transfer site (not shown) and remains on the surface of the image carrier 1 reaches the position of the cleaning blade 3, it will be scraped off by the blade 3 and will not be accumulated in the casing 4. This is the same as in the case of the device shown in the fourth section.

In such a configuration, in the illustrated device the casing 4
The inner surface of the portion where the blade support member 2 is attached to the casing is formed into a curved surface having an appropriate curvature so as to be concave toward the inside of the casing, as indicated by reference numeral 4a.

With such a configuration, when the toner that has been scraped off by the cleaning blade 3 and gradually grows in the vicinity thereof reaches the curved surface 4a, the toner is scraped off by the cleaning blade 3.
Rather than being pushed toward the top of the casing, it is guided by the curved surface 4a and smoothly moves toward the back of the casing along arrow e, collapses without agglomeration, and accumulates at the back.

According to the results of experiments, the radius of curvature of the curved surface 4a is 10 mm or more, regardless of the distance from the contact point of the cleaning blade to the image carrier to the top of the casing, and the angle f formed between the support member 2 and the top surface of the casing. It is necessary.

Further, if the angle j between the tangent line drawn to the image carrier 1 and the direction of the support member 2 at the point i is 28°, the direction of the image carrier 1 is smaller than the direction of gravity until the angle is approximately 45°. The toner is stored one by one due to the pressure applied to the toner by the rotation.

FIG. 2 shows another embodiment of the present invention. In the illustrated apparatus, a cleaning blade 3 is bonded to a supporting member 21, and bent portions 9 formed at both ends of the supporting member 21 (see FIG. (only one of which is shown) is with the casing in place.

As shown in the drawing, the support member 2 is formed concavely toward the inside of the casing, and the collected toner is guided to the back side along this curved surface.

The radius of curvature of the curved surface formed on the top side of the support member 2 is the same as in the previous embodiment. In this case, in order to prevent the contact angle of the cleaning blade to the image carrier from becoming inaccurate due to the curved support member 2, the end edge a on the side to which the cleaning blade 3 is bonded is made flat. It is preferable to form it into a shape.

FIG. 3 shows still another embodiment of the present invention, in which a cleaning blade 3 is used. It is configured such that it is sandwiched between a pair of support members 12 and 12 and attached to the casing 4.

In such a configuration, as shown in the figure, SuS,
A guide plate 10 made of a suitable material such as polyethylene terephthalate or polypropylene is provided with a radius of curvature of 10φ or more.

The plate has a thickness of about 11ff1 and a surface roughness of R.
It is better to set it to 154im or less.

By adopting such a configuration, it is possible to correspond to the cleaning device that has been commonly used by simply making a slight design change.

(3) As described in detail, according to the present invention, in a cleaning device using a cleaning blade, the toner collected in the device is fully utilized sequentially to the back of the toner storage portion. It is possible to store as much toner as possible, and particularly when applied to a cartridge-type image forming apparatus, a remarkable effect can be obtained.

[Brief Description of the Drawings] Fig. 1 is a side sectional view of a cleaning device showing an embodiment of the present invention, Figs. 2 and 3 are side sectional views showing other embodiments of the invention, and Fig. 4. , FIG. 5, and FIG. 6 are side sectional views illustrating the operation of a known cleaning device. DESCRIPTION OF SYMBOLS 1... Image carrier, 2... Supporting member, 3... Cleaning blade, 4... Casing, 5... Screen sheet, 10... Guide plate.

Claims (4)

[Claims] (1) In a cleaning device equipped with a cleaning blade that presses against the image carrier surface, the toner that naturally accumulates is collected on the inner wall surface of the cleaning device casing above the edge of the cleaning blade that presses against the image carrier, and guides the toner that naturally accumulates to the back side. A cleaning device formed by forming a curved surface. (2) The cleaning device according to claim 1, wherein the means for forming the curved surface is an inner wall surface of the casing. (3) The cleaning device according to claim 1, wherein the means for forming the curved surface is a support member that supports the cleaning blade. (4) The cleaning device according to claim 1, wherein the means for forming the curved surface is a separate plate formed in a curved shape and disposed above the cleaning blade.