JPH02146072A - Magnetic brush developing device - Google Patents

Abstract

PURPOSE:To obtain uniform recording density in any position of a recording sheet by fitting a guide covering the top of a blade fitting screw so that a blade for regulating toner napping has a surface shape uniformly formed in the full length of a developer entering surface. CONSTITUTION:This device is provided with the blade for regulating toner napping 13 fixed on a blade fixing member 14 by a screw 17, and the guide 25 covering a screw top 17a. Thus, the blade 13 has the surface shape uniformly formed in the full length of the developer entering surface B, and accordingly an ununiform projecting part disappears, so that uniform fluidity of developer 12 is obtained in any position in the axial direction of a developing roller 11. Therefore, uniform recording density can be obtained in the whole area of a recording sheet.

Description

[Detailed Description of the Invention] [Summary] Regarding a magnetic brush developing device used in an electrophotographic recording device, an object of the present invention is to realize a magnetic brush developing device that can obtain uniform recording density over the entire area of recording paper. In a structure in which a blade for regulating the height of the developer is fixed to a blade fixing member with a screw, the blade has a guide that covers the tip of the screw so that the blade has a uniform surface shape over the entire length of the developer inlet surface. The configuration consists of:

[Industrial Field of Application] The present invention relates to a magnetic brush developer used in an electrophotographic recording device.

[Overview of electrophotographic equipment]

An electrophotographic recording apparatus uses a photoreceptor as a latent image carrier, and performs recording through the steps of -like charging, image exposure, development, transfer, fixing, cleaning, and charge removal.

FIG. 5 is a side view illustrating the outline of the electrophotographic apparatus.

A charger 2, an image exposure means 3, a developing device 4, a transfer device 6, a cleaning blade 7, and a static eliminator 8 are arranged in this order around the continuously rotating photosensitive drum 10. In this apparatus, electrophotographic recording is performed through the following steps.

■ While the photosensitive drum 10 is rotating clockwise, the photosensitive drum 10, which is a latent image carrier, is charged by the charger 2.
The surface of is charged uniformly over its entire width.

(2) Next, when the −-like charged surface arrives at the position of the image exposure means 3, a predetermined image exposure is performed by the image exposure means 3, and an electrostatic latent image is formed on the photosensitive drum IO.

(2) The electrostatic latent image on the photosensitive drum 10 is made into a visible image by applying toner in a developing device 4 filled with a developer 12.

(2) The visible image on the photoreceptor 10 is electrostatically transferred onto the recording paper 5 by a transfer device 6 using a corona discharger.

(2) The image thus transferred onto the recording paper 5 is fixed to the recording paper 5 by the fixing device 9.

■On the other hand, the developer remaining on the photosensitive drum 10 after transfer is
Charges removed from the photosensitive drum 10 by the cleaner 7 and remaining on the surface of the photosensitive drum 10 are removed by the static elimination lamp 8 and initialized.

Incidentally, the developing device 4 includes a developing roller 11 and a blade 13 that faces the developing roller with a predetermined gap (referred to as a blade gap) interposed therebetween. Developing roller 1
1 is magnetized, and a powdered developer carrier having magnetism is attracted to the outer periphery of the developing roller 11 in the form of a brush.

Since developer is attached to the carrier, the rotation of the developing roller 11 transports and supplies the developer to the latent image surface of the photosensitive drum 10, thereby performing development.

The blade 13 regulates the height of the developer to a constant height.

[Conventional technology]

FIG. 6 is a side view showing the blade attachment portion of the magnetic brush type developing device.

A developing roller 11 is provided close to the photosensitive drum 10,
The developer is transported to the development position A by the development roller 11.

FIG. 7 is a front view showing the developing roller and blade gap adjustment mechanism of the developing device. In the figure, blade 13
The gap G between the developing roller 11 and the developing roller 11 is a blade gap, and the blade gap is adjusted by adjusting the position of the blade 13 with an adjustment screw 22.

The blade fixing member 14 is fixed by a screw 16 to an arm 15 provided integrally with the bearing 23 of the developing roller 11, and a screw 17 for attaching the blade 13 is inserted into the blade fixing member 14. A long hole 18 is formed.

The elongated portion 18 is elongated in the vertical direction of the blade, allowing the blade to move up and down.

When attaching the blade 13, the blade 13 is temporarily fixed with the screw 17, and the left and right adjustment screws 22 are rotated to adjust the blade gap.

In this case, when the adjusting screw 22 rotates, the adjusting screw 22
moves up and down, and the blade 13, which is connected to the head 19 of the adjustment screw 22 through the locking slit 20, moves up and down to adjust the blade gap.

Finally, the screws 17 are tightened to complete the attachment of the blade 13.

[Problems to be Solved by the Invention] FIG. 8 is a side view illustrating how the blade is attached.

The blade 13 is a non-magnetic thin plate-like member, which has a threaded burring hole into which a screw 17 is inserted, and is fixed to the blade fixing member 14 with the screw 17. Therefore, the screw tip L7a protrudes to the developer surface B.

FIG. 9 is a diagram explaining the screw tip 17a of the blade fixing screw 17, (a) is a perspective view, and (b) is a screw tip 1.
7a is a sectional view taken along line AA.

(a) As shown in the figure, the screw tip 17a protrudes from the surface of the blade 13, which becomes the developer entrance surface.

The screw tip 17a protrudes by a height d together with the bur ring 24, as shown in FIG. d is about 2 theories.

If such a protrusion exists on the developer inlet surface, it will interfere with the fluidity of the developer, and the developer density will decrease in that area.
This results in uneven development.

FIG. 10 is a diagram illustrating the development results with the conventional blade configuration.

The recording paper 5 was advanced in the direction of arrow S relative to the blade 13 for recording. As a result, a portion of low recording density appears in a portion of the width P of the recording paper 5 corresponding to the screw tip 17a.

A technical object of the present invention is to provide a magnetic brush developer which can solve these problems in the conventional magnetic brush developer and provide a uniform recording density over the entire area of recording paper.

[Means to solve the problem]

FIG. 1 is a diagram illustrating the principle of a blade according to the present invention. (a) is a side view, and (b) is a perspective view.

The blade 13 for regulating the height of the developer, which faces the developing roller 11 via a predetermined gear and extends in the axial direction of the developing roller 11, has a thickness equal to that of the screw that fixes the blade 13 to the blade fixing member 14. The tip of 17 is the developer entrance surface B
The thickness of the cover is such that it does not protrude further, and the entrance surface B has a uniform surface shape over its entire length. That is, in the figure, the tip of the screw 17 is thick enough not to protrude from the blade surface.

FIG. 2 is a diagram illustrating the principle of the guide according to the present invention. (a) is a side view, and (b) is a perspective view.

In a structure in which the blade 13 for regulating the developer spike height is fixed to the blade fixing member 14 with a screw 17, the blade 13 is fixed with the screw so that the blade 13 has a uniform surface shape over the entire length of the developer inlet surface B. This configuration includes a guide 25 that covers the tip 17a.

[Effect]

According to the present invention, (1) the thickness of the blade 13 for regulating developer spike height is made so as to cover the tip of the screw 17 for fixing the blade 13 to the blade fixing member 14 so as not to protrude from the surface of the blade 13; Thus, the surface shape of the developer inlet surface B is uniform over the entire length thereof.

(2) Alternatively, in a structure in which the blade 13 for regulating the height of the developer is fixed to the blade fixing member 14 with a screw 17, the blade 13 has a uniform surface shape over the entire length of the developer inlet surface B. , a configuration comprising a guide 25 that covers the screw tip 17a.

In any of the above cases, since there are no uneven protrusions on the developer inlet surface B, the developer can have uniform fluidity at any position in the axial direction of the developing roller.

〔Example〕

FIG. 3 is a diagram illustrating an embodiment of the guide according to the present invention.

Non-magnetic members are used for all guides shown in (a), (b), and (c).

For the guide 25a shown in FIG. 9(a), the thickness l of the guide is the same as the protrusion height d of the screw tip 17a shown in FIG. 9(b).
A U-shaped notch 27 is provided at a position to engage with the screw tip 17a.

Such a guide 25a is connected to the blade 1 in FIG. 9(a).
It is used by pasting it on the surface of No. 3 using an adhesive member.

FIG. 4 is a diagram illustrating the development results when such a blade is used, and recording was performed by advancing the recording paper 5 in the direction of arrow S with respect to the blade 13.

In FIG. 4, when the screw tip 17a engages with the notch 27 of the blade, the protrusion of the screw tip 17a is smoothed, and the developer can obtain uniform fluidity.

Therefore, uniform recording density could be obtained at any location on the recording paper 5.

Further, the guide 25b shown in FIG. 3(b) is used by being attached to the surface of the blade 13 shown in FIG. 9(a) using an adhesive, similarly to the guide described above. As a result, guide 25
By covering the screw tip 17a, a uniform surface shape can be obtained.

The guide 25c shown in FIG. 3(c) is provided with a screw hole 26 at a position where it engages with the blade mounting screw 17, and so as not to appear on the surface of the guide 25c. That is, the screw 1 is attached to the surface of the blade 13 in FIG. 9(a).
When the blade 13 is fixed at 7, the guide 25c is fixed together to obtain a uniform surface shape.

〔Effect of the invention〕

As described above, the blade for regulating the developer spike height has a uniform surface shape over the entire length of the developer artificial surface B. For this purpose, for example, the tip 17 of the screw 17 is used for attaching the blade.
A guide 25 covering a is attached to the blade 13.

With this configuration, the developer can obtain uniform fluidity at the entrance surface, and uniform recording density can be obtained at any location on the recording paper.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the blade according to the present invention.
(a) is a side view, (b) is a perspective view, and Figure 2 is a diagram explaining the principle of the guide according to the present invention. (a) is a side view, (b) is a perspective view, and The figures are diagrams illustrating embodiments of the guide according to the present invention, (a), (b), and (c) are perspective views of the respective embodiments, and Fig. 4 is a diagram showing how the guide of the embodiment according to the present invention is attached. Figure 5 is a side view illustrating the outline of the electrophotographic apparatus; Figure 6 is a side view illustrating the blade attachment of the magnetic brush developer. Figure 7 is a front view illustrating the adjustment mechanism of the developing roller and blade gap of the developing device; Figure 8 is a side view illustrating the installation state of the blade; Figure 9 is a view of the blade fixing screw. This is a diagram explaining the tip (
Figure a) is a perspective view, figure (b) is a sectional view taken along the line A-A of the screw tip 17a, and Figure 10 is a diagram illustrating the development result with a conventional blade configuration. In the figure, 1 is a cylindrical support, 2 is a charger, 3 is an image exposure means, 4 is a developer, 5 is a recording paper, 6 is a transfer device, 7 is a cleaning blade, 8 is a static elimination lamp, 9 is a fixing device, 10 is a photosensitive drum, 11 is a developing roller, 12 is a developer, 13 is a blade, 14 is a blade fixing member, 15 is an arm, 17 is a screw, 17a is a screw tip, 18 is long, 19 is a head, and 20 is a locking member. A stop slit, 22 an adjustment screw, 23 a bearing, 24 a burring, 25 a guide, 26 a punching hole, and 27 a cutout are shown. Patent Applicant: Fujitsu Limited, Sub-Agent, Patent Attorney: Yasufumi Fukushima (Q), Rijinokuni (υ), Figure 2, Retoguchi, Sun, Moon, Meiji Sai, 3. Ink 1b; 1st appearance 4
Yutoi, No. 42 5C No. 32 Den-e-shaku-shu-o-graduation 2-day-closing, 5th-ku present-day-in-painting-view/1st-view Figure 6nl; Shibo-no'7cA Ikuhty+ A-A-view (b
) Braid blade corner screw 9 concave inkstone roller blade 5 blade knob fitting 7th section Conventional blue course 1; current 1 Hagi, Yuka line 10u

Claims (1)

[Scope of Claims] In a structure in which a blade (13) for regulating developer spike height is fixed to a blade fixing member (14) with a screw (17), the blade (13) is attached to a developer inlet surface (B). The tip of the screw (17
A magnetic brush developing device comprising: a) a guide (25) that covers the magnetic brush developing device;