JPH0623919B2 - Cleaning device for electrophotographic copying machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cleaning device for an electrophotographic copying machine, and more particularly,
The present invention relates to a cleaning device that can prevent toner from falling off from the end of a cleaning blade.

(Prior Art) Around the photosensitive drum for an electrophotographic copying machine, for example, a charging charger, an exposing unit, a developing unit, a transfer charger, a cleaning unit, and the like are sequentially arranged along the rotation direction. . The photoconductor is charged by, for example, a charging charger and then exposed by an exposing unit to form an electrostatic latent image. Then, toner is applied to the photoconductor by, for example, a developing unit having a magnetic brush or the like formed on a sleeve to form a toner image corresponding to the electrostatic latent image. The toner image is then electrostatically transferred to the copy paper by the transfer charger. The copy paper on which the toner image has been transferred is then fixed by the fixing means. In the toner recycling method, the untransferred toner remaining on the surface of the photoconductor after transfer is temporarily accumulated and held on the surface of the photoconductor by a cleaning means such as a blade.
The residual accumulated toner is then conveyed to the vicinity of the developing sleeve of the developing means together with the photosensitive member by separating the blade from the surface of the photosensitive member. Here, the residual accumulated toner is removed from the surface of the photoconductor by controlling the bias voltage applied between the developing sleeve and the photoconductor drum.

In the cleaning process, the blade width is set smaller than the developing width in order to collect the toner by the developing sleeve. Therefore, the residual toner gradually deposited on both ends of the blade goes out of the width of the blade and further out of the width of the developing sleeve. As a result, the residual accumulated toner cannot be collected depending on the developing sleeve. This causes the transfer paper to become dirty. In order to prevent such leakage of the residual toner, sealing felt is applied to both ends of the blade. However, when the felt is placed in close contact with the blade, the felt fibers are caught between the blade and the photoconductor each time the blade moves up and down, and the felt is damaged and cannot be used at the same time. Due to the floating, cleaning failure occurs or the surface of the photoconductor is damaged, which adversely affects electrostatic latent image formation and toner image transfer in the next cycle. Therefore, the sealing felt must be placed with a certain clearance from the blade. As a result, there is a problem that the residual toner removed from the surface of the photoconductor by the blade falls through the gap between the blade and the felt.

On the other hand, since the sealing felt is usually made of natural animal hair, its fibers have a grain direction. Therefore, depending on the direction, there are cases where the effect of preventing toner drop cannot be achieved.

Due to such toner loss, the toner recovery rate is significantly reduced and the toner consumption amount is increased. Further, the dropped toner is scattered in the copying machine and adheres to the surface of the photoconductor to stain the toner image, and also adheres to electric parts and precision parts in the copying machine to hinder the smooth operation of the copying machine. There is.

(Object of the Invention) An object of the present invention is to provide a cleaning device for an electrophotographic copying machine, which can surely prevent toner from falling off from the end of the cleaning blade. Another object of the present invention is to
It is an object of the present invention to provide a cleaning device for an electrophotographic copying machine, which keeps the surface of the photoconductor clean without referring to it, thereby forming a good image. Still another object of the present invention is to provide a cleaning device for an electrophotographic copying machine, which keeps the inside of the copying machine clean and allows the copying machine to operate smoothly for a long period of time. Still another object of the present invention is to provide a cleaning device for an electrophotographic copying machine having a simple structure.

(Constitution of the Invention) The cleaning device of the present invention is used, for example, in a toner recycling type electrophotographic copying machine. In the toner recycling method, the toner remaining on the surface of the photoconductor after the toner transfer is first accumulated and held on the surface of the photoconductor by the cleaning blade. Next, by separating the blade from the surface of the photoconductor, the residual toner accumulated on the surface of the photoconductor is conveyed to the vicinity of the developing sleeve in the developing device according to the rotation of the photoconductor drum. Then, by controlling the bias voltage applied between the developing sleeve and the photoconductor, the residual accumulated toner on the surface of the photoconductor is transferred onto the developing sleeve by electrostatic attraction and collected. therefore,
A cleaning device for an electrophotographic copying machine according to the present invention comprises a cleaning blade arranged in the vicinity of and above a photosensitive drum so as to be movable toward and away from the surface of the photosensitive drum, and both end portions in the longitudinal direction of the cleaning blade. A toner guiding protrusion protruding inward from both ends of the cleaning blade, which is disposed at a predetermined gap and is located upstream of the cleaning blade in the rotation direction of the photosensitive drum. The cleaning guide is provided with a sealing felt, and the toner guided by the toner guiding protrusion toward the center of the surface of the photosensitive drum is once accumulated and held by the cleaning blade and then conveyed to the downstream side. The above object is achieved by the above.

In the cleaning device of the present invention, as the sealing felt, the fibers of the fibers are oriented in a direction perpendicular to the axial direction of the drum, the same direction as the rotating direction of the drum or the opposite direction, or the axial direction of the drum. The direction is parallel to the center of the drum, or oblique to the axial direction of the drum, and the direction is the same as the direction of rotation of the drum. By doing so, the above object is achieved.

(Examples) The present invention will be described below with reference to Examples.

As shown in FIGS. 1, 2, and 3, the cleaning device of the present invention includes a cleaning blade 2 arranged near and above the photosensitive drum 1 and seals arranged at both ends of the cleaning blade 2. With felt 3 for. The photoconductor drum 1 has a photoconductor 10 made of a photoconductive substance such as selenium on the outer peripheral surface thereof.

The cleaning blade is provided so that the toner 601 remaining on the surface of the photoconductor 10 after the transfer of the toner image is temporarily accumulated on the surface of the photoconductor 10 and then driven upward.
The material of the cleaning blade 2 is a substance that does not damage the surface of the photoconductor 10, for example, a synthetic resin type elastic material such as rubber type or polyurethane elastomer. The width of the blade 2 is not particularly limited, but is usually set smaller than the developing width and larger than the transfer paper width. For example, two blades 2 are arranged in parallel at a predetermined interval.

One end of each of the above-mentioned sealing felts 3 is supported and fixed to the fixing portion, and the other end is in contact with the surface of the drum photosensitive member 10. The pair of sealing felts 3 have, on their opposite side surfaces (side surfaces on the blade side), protruding portions 31 in the shape of a hook and a fin that cover the ends of the blade 2. The protrusion 31 has a function of guiding the residual toner 601 on the surface of the photoconductor 10 toward the center of the surface. As a result, it is possible to reliably prevent the toner from dropping from the end portion on the blade 2 side. This felt 3 also has a protrusion
31 is provided with a predetermined gap 30 from the end of the blade 2.
The gap 30 is, for example, in the range of about 1 mm to 2 mm.
Therefore, the fibers of the felt 3 are, for example, wool or other animal hair as the sealing felt 3 which is not likely to be caught between the blade 2 and the surface of the photoconductor 10 even if the blade 2 moves up and down. Is immersed in a warm soap solution or a warm sulfuric acid solution, then compressed into a cloth shape and molded, and after the molding, the fiber direction of the fibers is given in a predetermined direction. The fibers are provided in the eye direction by, for example, placing a weight on the felt and applying a load to the fibers of the felt to make the fibers in the predetermined direction. According to such a curling method, the eye direction of the fiber can be set to a fixed direction by selecting the load application method. The specific fiber direction will be described later. Felt made of synthetic fibers may also be used. The fiber length of the felt 3 is about 4 mm or less, preferably 2 mm to 3 mm.
It goes without saying that the higher the flocking density is, the better the prevention of toner loss. An elastic body such as a rubber plate may be appropriately provided on the back surface of the felt 3.

In order to further enhance the effect of preventing the toner from falling off, the sealing felt 3 has, for example, as shown in FIGS. 3 (a) to 3 (d), the fiber grain direction 32 is the axial direction of the drum 1. Direction parallel to the direction toward the center of drum 1, drum 1
The direction perpendicular to the axial direction of the drum 1 and the direction opposite to the drum rotating direction 11 and the direction perpendicular to the axial direction of the drum 1 in the same direction as the drum rotating direction 11 or oblique to the axial direction of the drum 1. Therefore, it is squeezed so as to be in one of the directions that are the same as the drum rotation direction 11. In other words, the fiber grain direction 32 is parallel to the axial direction of the drum 1 and is bent in a direction other than the direction toward the end of the drum (hereinafter referred to as the drum side end direction).

A commercially available electrophotographic copying machine (DC-2
11: manufactured by Mita Kogyo Co., Ltd.), and an experiment was conducted to check for toner loss.

Experimental Example 1 The sealing felt 3 of the cleaning device of the present invention was arranged at the end of the blade 2 with a gap of about 1.45 mm to 1.6 mm.
As shown in FIG. 7, the original 51 used in the experiment has solid black portions 52 at a part of both ends of the paper. When an acceleration copying test was conducted on the original 51 in a simulation mode for 30 minutes (paper passing and transfer are continuously repeated), neither toner drop nor biting by the blade 2 was observed. The results are shown in Table 1 below.

Comparative Example 1 As shown in FIG. 4, the procedure is the same as that of Experimental Example 1 except that the sealing felt 300 used in the conventional cleaning device is placed in close contact with the end portion of the blade 2. Although toner drop could be prevented as in Experimental Example 1, the fibers of felt 300 were caught in the surfaces of the blade 2 and the drum photoconductor 10 and did not fulfill the sealing function. The results are shown in Table 1 below.

Comparative Example 2 As shown in FIG. 5, the felt 300 used in Comparative Example 1 was placed at the end of the blade 2 with the same gap as in Experimental Example 1 and the same test was conducted. No biting of the felt 300 by the blade 2 was observed, but toner fell from the gap between the blade 2 and the felt 300. The results are shown in Table 1 below.
Shown in.

Next, the influence of the eye direction 32 of the sealing felt 3 of the cleaning device of the present invention on the toner drop was examined in the same manner as in the above experiment.

Experimental Example 2 As shown in FIG. 3 (a), the fiber direction 32 of the felt 3 was measured.
With respect to the drum rotation direction 11, the blade 2 side direction (drum 1
The test was conducted in the same manner as in Experimental Example 1 by aligning with the direction parallel to the axial direction of (1) (the direction toward the center of the drum 1). No toner loss was observed. The results are shown in Table 2 below.

Experimental Example 3 As shown in FIG. 3 (b), a test was conducted in the same manner as in Experimental Example 1 by aligning the eye direction 32 of the felt 3 fibers in the direction opposite to the drum rotation direction 11. No toner loss was observed. The results are shown in Table 2 below.

Experimental Example 4 As shown in FIG. 3 (c), the eye direction 32 of the felt 3 fibers was aligned in the same direction as the drum rotation direction 11, and the same test as in Experimental Example 1 was conducted. Although a slight toner drop was observed, the operation of the copying machine was hardly affected. The results are shown in Table 2 below.

Experimental Example 5 As shown in FIG. 3 (d), the test was performed in the same manner as in Experimental Example 1 by aligning the eye direction 32 of the felt 3 fibers in the same direction as the drum rotation direction 11 and in the direction inclined to the blade 2 side. went. No toner loss was observed. The results are shown in Table 2 below.

Comparative Example 3 As shown in FIG. 6, a test was conducted in the same manner as in Experimental Example 1 by aligning the grain direction 32 of the felt 3 fibers with the drum 1 side end direction with respect to the drum rotation direction 11. A lot of toner felt
It was observed to cross over 301 and fall into the plane. The results are shown in Table 2 below.

(Effects of the Invention) According to the present invention, by thus forming the cleaning felt side of the sealing felt on the fin side, it is possible to reliably prevent the toner from dropping from the end portion on the side of the cleaning blade. The direction of the sealing fibers is the direction perpendicular to the axial direction of the drum, the same direction as the rotating direction of the drum or the opposite direction, the direction parallel to the axial direction of the drum, and the direction toward the center of the drum. Further, the effect is further enhanced by aligning in any one of the directions which are oblique to the axial direction of the drum and are directed in the same direction as the rotating direction of the drum. As a result, the toner recovery rate is increased and the toner consumption is reduced. In addition, there is no risk of the felt fibers being caught by the vertical movement of the blade. Therefore, the sealing felt is not damaged, and good sealing performance can be maintained for a long time. The cleaning blade does not accidentally incline due to the sticking of the sealing felt to damage the surface of the photoconductor drum, and the life is improved. it can,
In addition to the effect that the moving and moving of the cleaning blade can be smoothly performed without any trouble, the cleaning blade and the surface of the photoconductor can be kept clean and a good image can be supplied. Since electric parts and precision parts in the copying machine are not contaminated due to toner falling, the copying machine can be operated stably for a long period of time. Further, since the structure is simple, maintenance work can be performed very easily.

[Brief description of drawings]

FIGS. 1 and 2 are front sectional views and plan views of essential parts showing an embodiment of the device of the present invention, and FIGS. 3 (a) to 3 (d) are embodiments of the device of the present invention. FIG. 4 is a plan view of a main part showing an example of the prior art, and FIG. 6 is a plan view of a main part showing a comparative example of an experimental example of the device of the present invention. The drawing is a plan view showing an image paper used in an experimental example of the device of the present invention. 1 ... Photosensitive drum, 2 ... Cleaning blade,
3, 300, 301 …… Seal felt, 4, 7 …… Charger, 5 …… Optical system, 6 …… Developer, 8 …… Copy paper, 10 …… Photosensitive member, 11 …… Drum rotation direction, 30 …… Gap, 31 …… Projection, 32 …… Felt eye direction, 51 …… Original, 52 …… Solid black area, 60 …… Toner, 61 …… Developing sleeve, 62 …… Bias voltage, 601 …… Residual toner .

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Jiro Fujii 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Mita Mita Industry Co., Ltd. (72) Yasushi Kamezaki 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka No. Mita Kogyo Co., Ltd. (72) Inventor Mamoru Kato 1-2-2 28 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (72) Masahiko Maeda 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka No. Mita Kogyo Co., Ltd. (72) Inventor Toshio Nishino 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (72) Masazumi Yabada 1-228 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka No. Sanda Kogyo Co., Ltd. (72) Inventor Tetsutaka Okazaki 1-2-2 Tamatsukuri, Higashi-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (56) Reference JP-A-58-122578 (JP, A) JP-A-59-72470 (JP, A) Actually developed JP-A-58-159548 (JP, U)

Claims (6)

[Claims] 1. A cleaning blade disposed near and above the photosensitive drum so as to be movable toward and away from the surface of the photosensitive drum, and a predetermined gap is provided at both ends in the longitudinal direction of the cleaning blade. And a sealing felt having a toner guide protrusion protruding inward from both ends of the cleaning blade at a portion located upstream of the cleaning blade in the rotation direction of the photosensitive drum. A cleaning device for an electrophotographic copying machine in which the toner guided by the toner guiding protrusion toward the center of the surface of the photosensitive drum is temporarily accumulated and held by the cleaning blade and then conveyed to the downstream side. 2. The cleaning device for an electrophotographic copying machine according to claim 1, wherein the length of the fibers of the sealing felt is within the range of about 2 mm to 3 mm. 3. The cleaning device for an electrophotographic copying machine according to claim 1, wherein the back surface of the sealing felt is made of an elastic material. 4. A cleaning blade disposed near and above the photosensitive drum so as to be movable toward and away from the surface of the photosensitive drum, and a predetermined gap is provided at both ends in the longitudinal direction of the cleaning blade. And a sealing felt having a toner guide protrusion protruding inward from both ends of the cleaning blade at a portion located upstream of the cleaning blade in the rotation direction of the photosensitive drum. A cleaning device for an electrophotographic copying machine, in which the toner guided by the toner guiding protrusion toward the center of the surface of the photosensitive drum is temporarily accumulated and held by the cleaning blade, and is then conveyed to the downstream side. The fiber direction of the felt for felt is the direction perpendicular to the axial direction of the drum, and the same direction as the rotating direction of the drum or the opposite direction, In the direction parallel to the axial direction of the drum and toward the center of the drum, or oblique to the axial direction of the drum and in the same direction as the direction of rotation of the drum. A cleaning device for an electrophotographic copying machine. 5. The cleaning device for an electrophotographic copying machine according to claim 4, wherein the length of the fibers of the sealing felt is within the range of about 2 mm to 3 mm. 6. The cleaning device for an electrophotographic copying machine according to claim 4, wherein the back surface of the sealing felt is made of an elastic material.