JPH0721686B2 - Cleaning blade and image forming apparatus using the cleaning blade - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Industrial field of application) The present invention relates to a cleaning blade used in an image forming apparatus utilizing an electrostatic transfer process, such as an electrostatic copying machine and a printer, and a cleaning blade for the same. The present invention relates to an image forming apparatus used.

(Problems to be Solved by Prior Art) In the known image forming apparatus as described above, it is necessary to sufficiently remove the residual toner remaining on the surface of the image carrier even after the transfer in order to obtain a high quality image. It is mandatory.

As a means for removing the residual toner, various proposals have been made in the past, but a structure in which a cleaning blade made of an elastic material such as rubber is pressed against the image bearing member to scrape off the residual toner and remove the residual toner is provided. It is well known that it is widely used because it is simple, small and compact, and has an excellent toner removing function.

However, the cleaning blade is not without its drawbacks, and will be briefly described below.

FIG. 2 is a schematic side view of a main part of an image forming apparatus in which a cleaning blade is applied to a rotating cylindrical image carrier as a cleaning unit.

A cleaning device 11 having a cleaning blade 12 in pressure contact with the image carrier is disposed near the image carrier 10 that rotates in the direction of arrow A, and a transfer charger 15 is provided on the upstream side of the cleaning device 11. Is formed to form a transfer site.

The transfer material conveyed to the transfer portion through the conveying path 14 receives the toner previously formed on the surface of the image carrier 10 at the transfer portion, and then passes through the conveying path 16 to a fixing portion (not shown). Shall be transported.

The residual toner remaining on the image carrier without contributing to the transfer at the transfer portion proceeds as it is and is cleaned by the cleaning blade.
It is scraped off to 12 and stored in the cleaning device 11,
If necessary, it is discharged to the outside of the device.

As a method of pressing the cleaning blade against the surface of the image carrier, as shown in the figure, one edge of the free end of the blade is contacted so as to face the running direction of the image carrier (counter direction). However, in this case, the blade edge must be pressed against the surface of the image carrier with a uniform contact pressure over the entire length.

However, it is not always easy to evenly bring the blade edge of the cleaning blade into contact with the image carrier. Next, this will be explained.

When the cleaning blade 12 is brought into pressure contact with the image carrier 10, the blade edge is naturally deformed, but FIG. 4 is an enlarged schematic view of the deformation mode.

In this case, a force for pressing the blade against the image carrier and a frictional force between the blade edge and the moving image carrier are applied to the blade edge, but the blade edge at this time is deformed in the axial direction of the image carrier. Considering the movement of the edge part in the central part of the edge or in the vicinity of it and the micro parts at both ends, in the central part, the adjoining micro parts of both sides adjoin each other with respect to the moving micro part. It acts to control the movement of minute parts.

However, at the minute portions on both ends, the suppressing action by one adjacent minute portion is weakened, so that the portions closer to the ends are more freely deformed, resulting in the shape shown in FIG.

With such a tendency, both ends are inevitably thin, resistance to pressing force and frictional force is reduced, and the blade is easily turned over.

Once the blade curl occurs, the blade curl is pulled by this and the blade curl rapidly extends to the central portion of the blade, and the cleaning function is lost.

By the way, FIG. 3 shows a relational arrangement between the image carrier 10 and the cleaning blade 12 which is in contact with the image carrier 10, but both side edges of the photosensitive layer 17 formed by coating on the surface of the image carrier have uneven coating. It is inevitable that the irregular edge 17 'is formed by sagging.

Therefore, the image area where the image is actually formed is the photosensitive layer.
Reference numeral L indicates that the irregular edge portion 17 'of 17 is not affected.
It is set as shown in.

On the other hand, the toner removed by the cleaning blade may stagnate at least temporarily in the blade edge portion, and in this case, the toner may move in the longitudinal direction of the edge due to a so-called lateral running phenomenon. , To make sure to remove all these toners,
Normally, the photosensitive layer 17 is formed so as to extend beyond both edges thereof as shown in the drawing.

As described above, in the tendency of thinning the blade ends, in combination with the irregular movement of the edge due to contact with the irregular photosensitive layer end of the blade ends as described above, the blade from the blade ends The possibility of curling is inevitable.

In addition, since the image carrier, which has come to be used frequently in recent years, has a structure in which a primary charging device, a developing device, a cleaning device, and the like are integrated into a cartridge and the maintenance is free. When the flare is turned up, it is difficult to repair it, which is extremely inconvenient.

The present invention has been made to cope with such a situation, and it is an object of the present invention to provide a cleaning blade capable of preventing the blade from being turned over at both ends of the cleaning blade, and an image forming apparatus to which the cleaning blade is applied. It is intended.

(2) Configuration of the Invention (Technical Means for Solving the Problem and Its Action) In order to achieve the above object, the present invention provides an elastic cleaning blade having an abutting edge that abuts a moving object to be cleaned. A cleaning blade having a chamfered portion formed at the longitudinal end of the elastic cleaning blade so that the length of the edge in the longitudinal direction of the blade is smaller than the length of a portion distant from the edge, or In an image forming apparatus having an image carrier and an elastic cleaning blade having an abutting edge that abuts on the image carrier, the length of the edge in the longitudinal direction of the cleaning blade is different from that of the edge. A chamfer at the longitudinal end of the elastic cleaning blade so that it is smaller than the length. Formed is an image forming apparatus comprising.

With this configuration, it is possible to effectively prevent the blade from being turned over and obtain a good quality image constantly.

(Description of Embodiments) FIG. 1 is a plan view showing only an image carrier and a cleaning blade when the cleaning blade according to the present invention is applied to an image forming apparatus as shown in FIG.

A photosensitive layer 3 is formed on the surface of the image carrier 1, and the length of the photosensitive layer 3 as viewed in the axial direction of the image carrier is composed of an image region L and irregular portions 3 ′ such as coating unevenness on both outer sides. There is.

A cleaning blade 2 is in pressure contact with the image carrier 1. At both ends of the edge of the cleaning blade 2 that comes into pressure contact with the surface of the image bearing member, a cut portion (chamfered portion) 2 ', such that the length of the cleaning blade (as viewed in the axial direction of the image bearing member) becomes smaller as it approaches the edge. 2'is formed, and on the surface of the image carrier, the edge is formed so as to substantially match the image region L.

With this configuration, even if the cleaning blade is maintained in the operating state and both ends thereof are widened, the blade edge may contact the irregular portions 3'at both ends of the photosensitive layer and cause the blade to be turned over. It is possible to prevent the occurrence of cleaning failure and prevent the occurrence of cleaning failure.

The cut portion 2 '(chamfered portion) is not limited to the linear shape as shown in the drawing, and a rounded bet can be formed.

FIG. 1A is a perspective view of a main part of a cleaning blade showing another embodiment.

It is assumed that one edge of the cleaning blade 2 is held by the holding member 11 'attached to the cleaning device, and one edge 2E of the other edge is pressed against an image carrier (not shown).

At both ends of the edge 2E on the side that comes into pressure contact with the image carrier, there are formed triangular cut portions 2 ″ including the edges and having apexes on the three ridgelines of the blades gathering on the edges. (Only one end is shown in the figure).

It can be easily understood that even with such a configuration, the same effect as in the case of the above-described embodiment can be obtained by bringing the edge 2E into contact with the image carrier.

Further, the case where the present invention is applied to the copying machine has been described above, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to other image forming apparatuses such as a printer.

(3) Effects of the Invention As described above, according to the present invention, the chamfered portions are formed on both side surfaces in the longitudinal direction of the cleaning blade of the image forming apparatus to avoid the influence of deformation of the portion due to the contact pressure. As a result, a uniform contact pressure can be obtained over the entire length of the blade, the blade can be prevented from being turned over, and a good cleaning function can be stably maintained for a long period of time. By using this, an excellent image can be obtained in the image forming apparatus. There is a great deal of contribution to this.

[Brief description of drawings]

FIG. 1 is a plan view showing a relative arrangement of a cleaning blade and an image carrier when the present invention is applied to a cleaning device of a copying machine, and FIG. 1A is a perspective view of a main part of a cleaning blade showing another embodiment. FIG. 2 is a schematic side view of the copying machine showing the operation of the cleaning blade, and FIGS. 3 and 4 are plan views showing the relational arrangement between the cleaning blade and the image carrier of the same apparatus. 1, 10 ... Image carrier, 2, 12 ... Cleaning blade, 3, 17 ... Photosensitive layer, 11 ... Cleaning device.

Claims (2)

[Claims] 1. An elastic cleaning blade having an abutting edge that abuts a moving object to be cleaned, wherein the length of the edge in the longitudinal direction of the cleaning blade is smaller than the length of a portion distant from the edge. Thus, a cleaning blade having a chamfered portion formed at the end portion in the longitudinal direction of the elastic cleaning blade. 2. An image forming apparatus having a moving image carrier and an elastic cleaning blade having an abutting edge for abutting the image carrier, wherein the length of the edge in the longitudinal direction of the cleaning blade is: An image forming apparatus in which a chamfered portion is formed at an end portion in the longitudinal direction of the elastic cleaning blade so as to be smaller than a length of a portion away from the edge.