JPH031665B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a developer housing for an electronic reproduction apparatus.

Electronic copying devices usually perform copying by providing a charging section, an exposing section, a developing section, and a transfer section around a rotating photoconductor drum. To develop the image, many use a magnetic brush roll that supplies toner to the photoreceptor drum. However, when toner is supplied to the photoreceptor drum by this magnetic brush roll, a portion of the supplied toner collides with the photoreceptor drum, becomes a toner cloud, and flies upward. The toner that flies upward in this way adheres to the ceiling of the housing of the developing section and gradually accumulates, and at a certain point it falls in the form of a lump onto the magnetic brush roll, which is then supplied directly onto the photoreceptor drum and becomes attached. However, as a result, there was a risk that copying defects such as toner stains would occur.

In order to prevent the toner flying upwards from adhering to the ceiling of the developing unit housing, for example, the height of this ceiling can be made higher than the flying height of the toner, but even in such a case, Floating toner adheres and accumulates little by little,
As mentioned above, at a certain point it fell and caused toner stains.

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing unit structure for an electronic copying apparatus that can prevent copying defects such as toner stains caused by toner accumulated on the ceiling of a developing unit housing.

The developing section structure of the electronic copying apparatus according to the present invention is provided with a striking means for striking the ceiling of the developing section housing at a predetermined period, and the striking of the striking means prevents toner from accumulating on the ceiling of the developing section housing beyond a certain level. It is characterized by the following.

According to the structure of the developing section of the electronic copying apparatus of the present invention,
As described above, since the toner does not accumulate on the ceiling of the developing unit housing more than a predetermined amount, the toner does not fall in lumps onto the magnetic brush roll, thus preventing copying defects such as toner stains.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic copying apparatus according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the structure of a developing section of an electronic copying apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line - in FIG. 1.

In the figure, reference numeral 1 indicates a photoreceptor drum, and this photoreceptor drum 1 is supported so as to rotate in the direction of arrow A. As shown in FIG. A developing section 2 is provided adjacent to a portion of the photosensitive drum 1. The developing section 2 has a developing section housing 3, and a magnetic brush roll 4 is supported in the developing housing 3 adjacent to the photosensitive drum 1 so as to rotate in the direction of arrow B. . This magnetic brush roll 4
As is well known, there is a fixed magnet (not shown) inside the
is arranged, and the fixed magnet forms a magnetic field to attract the developer to the roll surface. A paddle 5 is provided diagonally below the magnetic brush roll 4, and this paddle 5 rotates in the direction of arrow C to remove the developer accumulated at the bottom of the developer housing 3 onto the surface of the main magnetic brush roll 4. It has the effect of lifting up to. The above-mentioned developer consists of toner and a carrier, and the toner adheres to the carrier due to frictional electrification. Toner is supplied alone to the developing section, and in order to form a developer having such a structure, a blender 6 is provided for mixing the supplied toner and carrier.

The developer with the toner attached to the carrier is attracted onto the surface of the magnetic brush roll 4 by the magnetic field, and is moved toward the photosensitive drum 1 as the roll 4 rotates. . At this time, the height of the developer is adjusted to an appropriate height by the trimmer 7. A so-called magnetic brush is formed on the surface of the magnetic brush roll 4, and the tip of this magnetic brush comes into contact with the surface of the photoreceptor drum, and the toner is applied to the latent image by the electric force of the latent image formed on the surface of the photoreceptor. It is attracted and developed.

However, due to the collision when the tip of the magnetic brush comes into contact with the surface of the photoreceptor drum, a phenomenon occurs in which the toner comes off the carrier and flies upward as shown by arrow T, forming a toner cloud. Therefore,
The position 4a where the magnetic brush on the magnetic brush roll 4 contacts the photoreceptor drum 1 and the ceiling 3 of the housing 3
The distance X between a is made longer than the flying height of the toner T flying from the position 4a. The flying height of this toner T is usually about 70 to 80 mm, so
It is desirable that the distance X be longer than this, for example about 90 to 100 mm.

However, even when the ceiling 3a of the housing 3 is made sufficiently high in this manner, the toner floating within the housing 3 adheres to the ceiling 3a and accumulates, albeit slightly.

Therefore, in the present invention, the striking device 10 is provided on the ceiling 3a of the housing 3, and this striking device 1
0, the ceiling 3a is struck at a constant cycle, thereby preventing toner from accumulating on the ceiling 3a more than a predetermined amount.

Next, details of the striking device 10 will be explained with reference to FIG. 2.

A bracket 11 is provided near one side of the ceiling 3a of the housing 3, and an L-shaped lever 12 is pivotally mounted on the bracket 11 at its longer arm 12a. A striking element 13 is attached to the tip of this longer arm 12a. On the other hand, near the tip of the shorter arm 12b of the lever 12, a plate member 14 is provided.
is fixed to the plate-like member 14, and a long groove 15 is formed in the plate-like member 14, extending from the tip thereof toward the part fixed to the plate-like member 14.

A solenoid 16 extending vertically is attached to the side wall 3b of the housing 3 near its upper edge, and an armature 16a of the solenoid 16
extends downward. A pin 16b is implanted at the tip of the armature 16a, and this pin 16b fits into the long groove 15 of the plate member 14 fixed to the lever 12. In addition, the symbol S in FIG. 2 indicates a spring, and this spring S
is for urging the lever 12 counterclockwise in the figure.

Next, the operation of the striking device 10 will be explained. When the solenoid 16 is energized for a certain period of time at a predetermined cycle so that not much toner accumulates on the ceiling 3a of the housing 3, the armature 16a expands.
The lever 12 is connected via the pin 16b and the plate member 14.
Rotate clockwise, hit the striker 13, and hit the ceiling 3.
Hit a. Note that this impact needs to be performed while development is not being performed. After this, when the energization to the solenoid 16 is stopped, the spring S
By this action, the lever 12 is rotated counterclockwise and returned to the initial position. Along with this, the armature 16a is also returned to the initial retracted position.
The above-mentioned impact of the impactor 13 prevents toner from adhering to the ceiling 3a in excess of a predetermined amount.

In addition, as shown by reference numeral 17 in FIG.
If a second striker is provided at the tip of the lever 2b to strike the mounting bolt 18 of the trimmer 7 during the return stroke of the spring S of the lever 12, more than a predetermined amount of toner will accumulate on the trimmer 7. You can also prevent it from happening.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure of a developing section of an electronic copying apparatus of the present invention, and FIG. 2 is a sectional view taken along the line - in FIG. 1. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Developing section, 3... Developing section housing, 3a... Ceiling, 10... Hitting device.

Claims (1)

[Claims] 1. A striking means is provided in the developing unit housing of the electronic copying apparatus, and the striking means has a striking element which is arranged at a distance from the ceiling of the housing and strikes the ceiling at a predetermined period. A developing unit structure of an electronic copying apparatus, characterized in that toner is prevented from accumulating on the ceiling of the housing beyond a certain level due to the impact of the above.