JPH0362059A - developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic copying machine, an electrostatic recording device, or a laser beam printer. It is related to the device.

Taedanami I A developing device used to develop an electrostatic latent image formed on an image carrier in an image forming apparatus such as an electrophotographic copying machine, which is a developing device supplied into a developing chamber equipped with a developing roller. agent,
A developing device is known in which the thickness of a developer layer is regulated using a developing blade brought into contact with a developing roller.

The developing blade has its upper end fixed to the lower back surface of the holding member, and is attached to the mounting surfaces provided inside the upper part of the semicircular arc-shaped inner wall at both ends of the developing chamber via the holding member,
Thereafter, it is curved and brought into contact with one side of the circumferential surface of a developing roller housed and installed in the developing chamber.

As mentioned above, the attachment of the developing blade to the surface within the developing chamber is carried out without bringing the developing blade into contact with the developing roller. Therefore, by positioning the mounting surface to the upper part of the developing blade, and attaching the upper part of the developing blade to the surface via the holding member, when the developing roller is subsequently housed and installed in the developing chamber. ,
It was ensured that the developing blade was in contact with the developing roller with a predetermined contact pressure.

However, conventionally, the reference surface for positioning the developing blade is set as the back surface of the upper part of the developing blade opposite to the side of the developing blade that comes into contact with the developing roller, and the mounting surface is set as the reference surface for positioning the developing blade. The developing blade was attached to the mounting surface via a holding member with the back surface of the developing blade positioned in the same plane as the mounting surface, that is, with the upper part of the developing blade positioned on the mounting surface.

For this reason, the thickness tolerance of the developing blade is affected,
When the developing roller is installed in the developing chamber, it is difficult to obtain the specified contact pressure on the developing blade, and even if the installation of the developing blade is finely adjusted before installing the developing roller in the developing chamber, the specified contact pressure cannot be achieved. It was difficult to obtain stable pressure.

For this reason, there is a problem in that the amount of developer applied onto the developing roller varies, and density unevenness occurs in the image obtained by development.

Therefore, it is an object of the present invention to install the developing blade at both ends of the developing chamber by simply attaching the developing blade to the surface, positioning and installing the developing blade with high precision, and then storing and installing the developing blade in the developing chamber. It is an object of the present invention to provide a developing device capable of easily bringing a developing roller into contact with a developing blade at a predetermined contact pressure.

The above-mentioned object is achieved by the developing device according to the present invention. To summarize, the present invention provides: - mounting surfaces of the developing blades at both ends of a developing chamber such that the developing blades are brought into contact with a developing roller housed in the developing chamber with a predetermined contact pressure; In the developing device positioned with respect to the developing blade, the mounting is performed using a surface as a reference surface for positioning the developing blade; The mounting is provided with a surface set as a contacting side on the same side as the side that contacts the developing roller, and the contacting side of the mounting is located in the same plane as the mounting surface, and the developing roller is The developing device is characterized in that the blade is attached to a surface. According to one aspect of the present invention, a support part that supports the developing blade from the back surface is provided in the developing chamber between the mounting part and the abutting part of the developing blade.

Oihohoku Examples of the present invention will be described in detail below.

FIG. 1 is a schematic configuration diagram showing a process unit equipped with a developing device according to an embodiment of the present invention.

As shown in FIG. 1, the process unit is of a cartridge type, and a photosensitive drum 2 serving as an image carrier that rotates in the direction a is arranged on the right side of the cartridge housing 1. Light image exposure (
An electrostatic latent image is formed on the photosensitive drum 2 by irradiating the original image with the scanning light (L) of the laser beam.

A charging device 4 for the photosensitive drum 2 is provided on the left side of the photosensitive drum 2.
A cleaning device 5 for the photosensitive drum 2 including a cleaning blade 5a is located above the charging device 4.

In this example, the charging device 4 is composed of a contact charging roller or a frictional charging roller, and the portion of the partition wall 6 between the charging device 4 and the cleaning device 5 near the photosensitive drum 2 is made to protrude upward. The photosensitive drum 2 is disposed within the protrusion 6a of the photosensitive drum 2, and
The charging roller constituting the charging device 4 is in contact with the circumferential surface of the photosensitive drum 2 at a position on the upstream side in the rotational direction a. The strip device 4 may be a corona charger.

The cleaning blade 5a of the cleaning device 5 is made of rubber or the like, and contacts the circumferential surface of the photosensitive drum 2 at a position upstream of the charging device 4 in the rotational direction of the photosensitive drum 2.

Below the photosensitive drum 2, a developing roller 8, which serves as a developer carrier of the developing device 7 and rotates in the b direction, is arranged. The developing roller 8 is housed and installed in the developing chamber 9 below the photosensitive drum 2, and is in contact with the circumferential surface of the photosensitive drum 2 below the photosensitive drum 2, or faces the photosensitive drum 2 with a predetermined narrow gap. It is located.

A developer storage chamber 1 is located on the left side of the developing chamber 9 via a partition wall 10.
1 is provided, and the developer stored in the storage chamber 11 is
It is sent out by the rotary supply member 12 and supplied into the developing chamber 9 through the opening 10a at the bottom of the partition wall 10.

A semicircular inner wall portion 13 is formed at both ends of the developer chamber 9, and a developing blade 14 is attached to a surface 15 inside the upper portion of the inner wall portion 13.
will be provided. A developer scattering prevention member 16 made of a flexible material is attached to the semicircular arc-shaped inner wall portion 13.
are in contact with the peripheral surfaces of both ends of the developing roller 8 in the developing chamber 9 to seal the developer in the developing chamber 9 and prevent the developer from leaking outward from both ends of the developing roller 8 .

The developing blade 14 is made of an elastic body such as a rubber plate such as urethane rubber or silicone rubber, or a metal leaf spring made of stainless steel or phosphor bronze. Developing blade 14
As described above, the upper inner side of the semicircular arc-shaped inner wall portion 13 is attached to the surface 15 via the holding member 17,
It curves into contact with one side of the circumferential surface of the developing roller 8 housed and installed in the developing chamber 9 .

The attachment of the developing blade 14 will be further explained.

That is, as shown in FIG. 2, the upper end of the developing blade 14 is attached and fixed to the lower part of the back surface of the holding member 17 using double-sided tape, adhesive, or the like. The upper inner side of the semi-circular arc-shaped inner wall portion 13 is attached using a screw 18b that is screwed into a screw hole 18a hidden in the surface 15, and the holding member 17 is attached from the upper surface by a fixing method such as being fixed to the surface 15.
As shown in FIG.
A developing blade 14 is attached to 5. Note that the upper end of the developer scattering prevention member 16 is also held down by both ends of the holding member 17.

At this time, according to the present invention, the reference surface for positioning the developing blade 14 using the surface 15 is set as the abutting side surface of the upper part of the developing blade 14 on the same side as the side of the developing blade 14 that contacts the developing roller. 15 is set and provided,
As shown in FIG. 4, the developing blade 14 is attached to the mounting surface via the holding member 17 with its upper abutting side surface located in the same plane as the mounting surface. Therefore, even if there is a thickness tolerance in the developing blade 14, it will not be affected, and the developing blade 14 can be positioned and attached with high precision. Therefore, the developing roller 8 can be installed in the developing chamber 9. At this time, it is possible to easily and stably obtain a predetermined contact pressure on the developing blade 14.

Therefore, there is no variation in the amount of developer applied onto the developing roller 8, and density unevenness does not occur in the image obtained by development.

Furthermore, according to the present invention, as shown in FIG. 4, the support part 19 that supports the developing blade 14 from the back side opposite to the contact side is provided between the upper part of the developing blade 14 and the contact part. It is provided in the partition wall 10 of 9. According to this, the developing blade 14 is supported from the back side, so that the developing roller 8
The contact pressure with the developing blade 14 becomes even more stable, and separation of the developing blade 14 from the holding member 17 is prevented.

In the above embodiments, a holding member 17 separate from the developing chamber 9 was used to attach the developing blade 14 to the surface 15 for attaching the developing chamber 9. However, the present invention is not limited to this, and as shown in FIG. As in the other embodiment shown, the developing blade 14 may be attached to the surface 15 in the same way as the holding member 17 using the holding member 20 extending from the upper part of the partition wall 10 of the developing chamber 9. Further, the attachment can be done by bonding the developing blade 14 to the side surface of the surface 15 with an adhesive or by providing the developing blade 14 by insert molding or the like.

As explained above, in the developing device of the present invention, the developing chamber is installed by setting the reference surface for positioning the developing blade by the surface to the same side as the side of the developing blade that comes into contact with the developing roller. As for the side surfaces, the mounting surface is set and the developing blade is mounted so that the contact side surface of the part is located in the same plane as the mounting surface. Even if there are tolerances, the developing blade can be positioned with high precision and attached to the surface without being affected by the tolerances. Therefore, the developing roller is housed in the developing chamber,
When installed, the developing blade can be easily brought into contact with the developing roller with a predetermined contact pressure, and as a result, the amount of developer applied onto the photosensitive drum can be kept constant, and the image obtained by development can be Density unevenness will no longer occur.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a process unit equipped with a developing device according to an embodiment of the present invention. 2 and 3 are explanatory diagrams showing how the developing blade is attached to the developing device of FIG. 1. FIG. FIG. 4 is a sectional view showing the developing chamber of the developing device shown in FIG. FIG. 5 is a sectional view showing a developing chamber of another embodiment of the developing device of the present invention. 8: 9: 13: 14 = 15: 17, 20 16: 19: Developing blade Developing chamber semi-circular inner wall part Developing blade mounting surface: Holding member scattering prevention member support part Fig. 4 Fig. 4 16 3 4

Claims (1)

[Scope of Claims] 1) The mounting surfaces on which the developing blades are attached at both ends of the developing chamber are arranged so that the developing blade contacts the developing roller housed in the developing chamber with a predetermined contact pressure. In a developing device positioned with respect to the developing blade, a reference plane for positioning the developing blade by the mounting surface is set such that the reference surface for positioning the developing blade on the mounting surface is in contact with the developing roller of the developing blade at the attachment portion of the developing blade to the mounting surface. The mounting surface is set and provided as an abutting side surface on the same side as the contacting side, and the abutting side surface of the attaching portion is positioned in the same plane as the attaching surface, and the developing blade is attached to the attaching surface. A developing device characterized by: 2) The developing device according to claim 1, further comprising a support portion provided in the developing chamber between the mounting portion of the developing blade and the abutting portion for supporting the developing blade from a back surface opposite to the abutting side surface.