JPH0345246Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a developer supply device of a wet developing device used in an electrophotographic copying machine or an electrostatic recording device, more specifically, a developer supply device in which nozzles are arranged near both ends of a developing roller. The present invention relates to a developer supply device that sprays developer toward the center of a developing roller substantially parallel to its axial direction.

(Prior Art) An example of a wet type developing device incorporated into an electrophotographic copying machine or the like will be described. Inside the machine, a photoreceptor drum serving as an electrostatic latent image carrier rotates in one direction, and a developing roller faces and approaches this photoreceptor drum so that it rotates in the same direction in the vicinity of the photoreceptor drum. One or two nozzles are arranged at approximately the center in the longitudinal direction of the developing roller with their tips oriented approximately perpendicular to the axial direction of the developing roller. Therefore, the developer flowing out from the nozzle tip hits the circumferential surface of the developing roller and spreads left and right.
Development is performed in the axial direction of the developing roller. However, in order to meet the high-speed copying process, it is necessary to restrict the amount of developer infiltrated into the developing roller as much as possible, so the range in which the developer hits the peripheral surface of the developing roller and spreads from side to side is small, and if the machine is tilted, Naturally, the developer flows only in the lower direction and does not flow in the higher direction, which causes developer leakage or uneven development, which deteriorates the image quality.

(Purpose of the invention) The present invention was made in order to eliminate the above-mentioned drawbacks of the prior art.The purpose of the invention is to provide a developer supply device that does not leak developer even when the machine is placed at an angle, and does not cause uneven development. Our goal is to provide the following.

(Structure of the invention) This object is achieved by a developer supply device equipped with a developer nozzle that injects developer from near both ends of the developing roller toward the center of the developing roller substantially parallel to the axis of the developing roller. Ru.

The illustrated embodiment will be explained in detail below.
In the figure, an electrostatic latent image carrier, in this case a photosensitive drum 1, is supported rotatably in the direction of arrow A. The outer ring of a ball bearing 2 is in contact with the non-developing area at both ends of the photoreceptor drum 1.
A roller shaft 3 is press-fitted into the inner ring. A developing roller 4 is fixed to the roller shaft 3, and the circumferential surface of the developing roller 4 and the photosensitive drum 1
A predetermined gap is maintained between the circumferential surface of the The developing roller 4 is rotated in the direction of arrow B, and is configured to move in the same direction as the photosensitive drum 1 in its adjacent area. The scraper 5 is a flexible plate made of rubber or plastic, and its free edge 5a is in pressure contact with the lower half of the developing roller 4, and its base edge 5b is a support plate made of a metal plate or a hard plastic plate. 6, and the support plate 6 is fixed to an immovable substrate by means not shown. The developer nozzles 7, 7 are arranged near both ends of the developing roller 4 in the axial direction and above the scraper 5, and their tips 7a, 7a are directed approximately parallel to the axial direction of the developing roller 4 and towards the center. There is. The developer nozzle 7 is communicated with a developer supply means through a pipe (not shown), and the developer flows out from the tip 7a of the developer nozzle 7 along the axial direction of the developing roller 4. A portion of the flowing developer directly wets the circumferential surface of the developing roller 4, but most of it falls onto the upper surface of the scraper 5 and is stored in a wedge-shaped space formed by the scraper 5 and the photoreceptor drum 1. Since the developer flows from both ends toward the center, the developer can join together and uniformly infiltrate the circumferential surface of the developing roller 4 along the axial direction of the developing roller 4. In this way, the developer is made to flow out from both ends of the developing roller toward the center, so even if the copying machine is tilted a little, the developer still flows from the higher developer nozzle, resulting in uneven development due to lack of developer. Never. In addition,
If the length of the developing roller is very long, there is a risk that the developer supply capacity from only the left and right developer nozzles will be insufficient, so at least one developer nozzle should also be directed toward the center of the developing roller. It is desirable that the

Incidentally, in the developer supply device according to the present invention, it is preferable that the developer discharge portion also be configured as described below. That is, in FIG. 2, the developer discharge section 10 has a bottom plate 10a that is inclined in one direction along the axial direction of a developing roller (not shown), and a discharge hole 5b is provided at the lowest end of the bottom plate 10a. However, it is normal. However, with this configuration, if the side of the discharge hole 5b is turned upward, the discharge efficiency will deteriorate, and if the height difference a is exceeded, there is a risk that the discharge will eventually leak into the machine. In order to eliminate such a fear, in FIG. 3, the developer discharge section 11 has a center protruding from its bottom plate 11a, and
It has a mountain-shaped slope with a height difference b. When the copying machine maintains a substantially water line position, a substantially equal amount of developer is discharged from the discharge ports 11b and 11c on both sides. However, if the machine is installed in an inclined state, the developer discharge part 11 will also remain in an inclined state. For example, if the discharge port 11b side is higher than the discharge port 11c side, more developer will flow to the discharge port 11c. If each discharge port is provided with the ability to discharge the total amount of developer solution, the developer discharge efficiency will not be reduced no matter which side it is tilted to, and developer leakage accidents will not occur. FIG. 4 shows two developing rollers 13 and 14 and a squeeze roller 1 in contact with the photosensitive drum 12.
5 is shown. A developer discharge section 16 is disposed to support these rollers, and this developer discharge section 16 has a third roller at its bottom.
As shown in the figure, a similar slope 17 is provided.
Although the developer nozzles are not shown, they are arranged above each of the developing rollers 13 and 14 and near both ends thereof, and their tips are oriented approximately along the axial direction of each developing roller. Not even.

In this embodiment, a photoreceptor drum is used as an example of the electrostatic latent image carrier, but of course it may be a recording body in an electrostatic recording apparatus.

(Effects of the invention) As is clear from the above explanation, the developer supply device of the present invention prevents developer from leaking even when the machine is placed at an angle, and can produce high-quality images without uneven development. It has the effect that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an embodiment of the present invention;
FIGS. 2 and 3 are sectional views of a developer discharge portion, respectively, and FIG. 4 is a sectional view showing another embodiment of the present invention. 1, 12...photosensitive drum, 4, 13, 14...
...Developing roller, 5... Scraper, 7... Developer nozzle, 10, 11, 16... Developer discharge section.

Claims (1)

[Scope of utility model registration request] A developing roller disposed opposite to an electrostatic latent image carrier rotating in one direction, and a developing roller disposed approximately parallel to the axial direction of the developing roller from near both ends of the developing roller in order to infiltrate the circumferential surface of the developing roller. A developer supply device including a developer nozzle that causes the developer to flow out toward the center.