JPS6352158A - Developing device - Google Patents

Abstract

PURPOSE:To perform excellent development, by individually adjusting the clearances between two developing rollers and a photosensitive body by using the two developing rollers and two adjusting means around the supporting shaft of one of the two rollers. CONSTITUTION:Since the center of an eccentric bush 17 fitted to the side wall 15 of a developing unit 3 is slightly eccentric to the supporting shaft 14 of a developing roller 5, the supporting shaft 14 is separated from a photosensitive body 1 when the bush 17 is rotated in the direction shown by the arrow (a) and, accordingly, the clearance between the photosensitive body 1 and roller 5 becomes larger. Moreover, when an operation knob 19 is rotated in the direction shown by the arrow (a), a shaft 21 is brought upward and the unit 3 is rotated counterclockwise around the supporting shaft 14 through a stud 23 and, accordingly, the clearance between a developing roller 4 and photosensitive body 1 becomes smaller. By individually adjusting the clearances between the photosensitive body 1 and developing rollers 4 an 5, excellent development can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a developing device used, for example, in an electronic copying machine.

(Prior Art) In order to improve image density, a developing device is provided with a magnetic developing roller '781 and a second magnetic developing roller facing the photosensitive drum in its developing unit.
Some types use a magnetic developing roller to supply developer to an electrostatic latent image on a photosensitive drum to make it visible.

By the way, in this developing device, the gear knob between the photosensitive drum and the first and second magnetic developing rollers has a large effect on the image density.

(Problems to be Solved by the Invention) However, in the past, it has not been possible to adjust the gap between one of the first and second magnetic developing rollers and the photosensitive drum, or the gap between the first and second magnetic developing rollers is adjustable. The gap between the magnetic developing roller and the photosensitive drum could not be adjusted and was fixed at a set value.

Therefore, due to the influence of the precision difference A between the parts, the gap precision of the other magnetic developing roller cannot be obtained, resulting in a problem that the image quality is reduced by 4 degrees.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a developing device in which the gaps between the first and second developing rollers relative to the image carrier can be adjusted individually. It is something to do.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a system in which an electrostatic latent image formed on an image carrier is rotatably supported by a support shaft within a developing unit. a first adjusting means for moving one of the developing rollers in a direction toward and away from the image carrier; and a second adjusting means for rotating the developing unit about the support shaft of the image carrier and moving the other developing roller in a direction toward and away from the image carrier. It is.

(Function) By providing the first and second adjusting means, the gap between the first and second developing rollers with respect to the image carrier can be adjusted individually.

(Example) The present invention will be described below with reference to an example shown in the drawings. In FIG. 3, reference numeral 1 denotes a photosensitive drum as an image carrier, and a developing device 2 is provided facing the photosensitive drum 1.

This developing device 2 has first, second, upper and lower magnetic developing rollers 4 and 5 rotatably disposed within a developing unit 3. The developing rollers 4 and 5 are arranged with a gap between them and the photosensitive drum 1. A toner conveying auger 6 is provided in the developing unit 3, and upper and lower mixers 7.8 are also provided. Furthermore, upper and lower doctor blades 9.degree. 10 are disposed between the developing rollers 4 and 5. Further, 11 and 12 are upper and lower collection plates, and 13 is an auto toner sensor.

On the other hand, as shown in FIGS. 1 and 2, a support shaft 14 (only the -i side is shown) is provided protruding from both ends of the magnetic development roller 5 on the lower side in the development unit 3. is a through hole 3 formed in the side surface of the developing unit 3.
a and is supported by the side frame 15 of the copying machine. A mounting hole 16 is formed in the side frame 15, and the support shaft 14 is inserted into the mounting hole 16 via a boss portion 18 of an eccentric bushing 17 constituting the first adjusting means A. The center of the boss portion 18 of the eccentric bushing 17 and the center of the support shaft 14 are shifted by δ (0.3 mm), and the rotation of the eccentric bush 17 allows the support shaft 14 to move slightly in the horizontal direction. It has become. The eccentric bush 17 is fixed by screws 17a, 17a.

Further, a second adjustment means B is provided at the rear of the eccentric bush 17. That is, reference numeral 19 denotes an operation lens attached to the side frame 15 of the copying machine via a bracket 20, and an adjustment screw 21 is screwed onto this operation lens 19. The upper end of the adjustment screw 21 is connected to a stud 23 that is attached to the side surface of the developing unit 3 via a bracket 22. By rotating the operation camera 19, the adjustment screw 21 is moved up and down, and the stud 23 is raised and lowered.

Next, the magnetic developing rollers 4 and 5 and the photosensitive drum 1 are
The method for adjusting the gap between First, when adjusting the gap between the lower magnetic developing roller 5 and the photosensitive drum 1, loosen the screws 17a, 17a, and then turn the eccentric bushing 17 in the direction of the arrow a, as shown in FIG. When the eccentric bushing 17 is rotated in the direction indicated by the arrow, the spindle 14 of the magnetic developing roller 5 moves in the direction away from the photosensitive drum 1, increasing the gap. Conversely, when the eccentric bushing 17 is rotated in the direction indicated by the arrow, The support shaft 14 moves in a direction closer to the photosensitive drum 1, and the gap becomes smaller. Note that after completing the gap adjustment, screws 17a,
17a is retracted to fix the eccentric bushing 17.

In addition, the upper magnetic developing roller 4 and the photosensitive drum 1
To adjust the gap between 14 in the counterclockwise direction, the gap becomes smaller. Conversely, when the operation camera 19 is rotated in the direction indicated by the arrow, the shaft 21 is lowered, the developing unit 3 is rotated clockwise about the spindle 14 of the magnetic developing roller 5, and the gap becomes wider.

As mentioned above, the upper and lower magnetic developing rollers 4
.

[Effects of the Invention] As explained above, according to the present invention, the gap between the first and second developing rollers can be individually adjusted with respect to the image carrier, and development can be performed satisfactorily under optimal gap conditions. It is something that plays.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view showing the gap adjustment means, FIG. 2 is a cross-sectional view thereof, and FIG.
The figure is a schematic configuration diagram showing a developing device. DESCRIPTION OF SYMBOLS 1... Photosensitive drum (image bearing member), 3... Developing unit), 4.5... First and second developing roller, 14...
... Support shaft, A... First adjustment means, B... Second adjustment means. Applicant's agent Patent attorney Takehiko Suzue Figure 1 - 32 countries Figure 3

Claims (1)

[Claims] In a system in which developer is supplied to an electrostatic latent image formed on an image carrier by first and second developing rollers rotatably supported by a support shaft within a developing unit, one of the developing rollers is connected to the electrostatic latent image formed on the image carrier. a first adjusting means that moves the developing roller toward and away from the image carrier; and a first adjusting means that rotates the developing unit about the spindle of the one developing roller to bring the other developing roller into contact with the image carrier. A developing device comprising: a second adjusting means for moving in a direction of separation.