JPS58171068A - Developing device - Google Patents

Abstract

PURPOSE:To simplify working stages and to improve productivity by the constitution wherein a developing sleeve and a magnet roll are supported mutually separately in the housing of a developing device. CONSTITUTION:A magnet roll 19 is supported and fixed at the shaft ends 19a, 19b thereof directly in the housing 6 of a developing device, and a sleeve 20 is supported rotatably by means of bearings 21, 22 in the housing 6 of the developing device separately from the roll 19. Since both rolls are supported separately in the housing in the above-mentioned way, accuracy can be assured with the sleeve 20 alone and since there is no stage for assembling magnets into the sleeve, the working stage is simplified and workability is improved. The cost is thus reduced and productivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an il image device in a sii* forming apparatus,
In particular, the present invention relates to an apparatus with an improved method of supporting a developing sleeve and a magnetic loaf.

Conventionally, a li4 image sleeve made of a non-magnetic hollow cylinder was provided inside the sleeve! 8 using the magnetic net cost and the relative speed difference between the two! A developing device that transports a liquid to a child position is known. Normally, such a developing sleeve has a magnetic roller pushed into the sleeve in order to improve the accuracy of the outer circumferential surface of the sleeve, and the magnetic loaf is fixed to the sleeve using 7 tensions, and the sleeve is aligned with the axis of the sleeve and the magnetic roller as a reference. The four outer surfaces were ground to ensure accuracy. In this machining process, since the sleeve contains a magnetic roller, it is impossible to bring a grinding tool made of a magnetic material close to the sleeve surface inadvertently, resulting in poor workability and high costs.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks, simplify the processing process, increase productivity, and provide a developing device having nine developing strips. This is the current* device in which the magnetic roller and magnetic roller are supported separately from each other in the casing of my device.

An embodiment of the present invention will be described below in comparison with a conventional device.

FIG. 1 shows an example of a developing device using a one-component developer, which is a cylindrical developing sleeve made of a non-magnetic material such as stainless steel, which is rotated counterclockwise as shown by the arrow in the figure. A magnet roach 2 is inserted into the hollow interior. The magnetic toner 6 is attracted onto the sleeve 1 by the mudnet fours 2. The magnetic grade 4, which is a thickness regulating member on the sleeve 1, and the nine opposing magnetic poles N provided on the magnetic roach 2 work together to adjust the thickness Km, which is thinner than the gap between them. Table't
The toner coated with jiK adheres to the electrostatic latent image on the photosensitive drum 5 at a position facing the photosensitive drum 5, and development is performed. Note that 6 in the figure is a 7Vi pot, which is a housing that also serves as a part of the hopper of the developing device.

By the way, in order to fix the toner image on the transfer paper, the toner is bound to the transfer paper using means such as heat or pressure. Because I let him do it, he naturally gets Il@. Practically,
The magnetic powder accounts for 10 to 60 parts by weight of the toner particles, but due to the difference in specific gravity between the resin and the magnetic powder, the volume occupancy of the magnetic powder in the toner particles is less than 20%.
lf, and since the volume occupancy of the magnetic powder in the toner is very small, the toner rises in the magnetic field, forming a long brush with sparse density at the aii position, unlike magnetic powder alone. It becomes K<. Therefore, if the thickness of the toner layer on the sleeve 1 is set to less than a few square centimeters, the toner layer on the sleeve 1 tends to be uneven and non-uniform.

The non-uniformity of this single layer of toner on the supporting member is likely to be directly reproduced in the developed image, and since the single layer of toner is dense, if variations in layer thickness occur, the surface of the photoconductor which is the electrostatic image holding member 5 will be affected. There is a risk of toner agglomeration or damage to the photoconductor. Therefore, in this sense, it is necessary to form a uniform thin layer of toner on the sleeve 1 in a developing method using a one-component magnetic toner.

Under these circumstances, in order to regulate the layer thickness of the toner on the surface of the sleeve 1, a magnetic blade 4, which is a thickness regulating member, is used.
must be in close proximity to the sleeve surface. Incidentally, in this example, with 250 houses between the two, the thickness of the toner layer is approximately 8.
0 to 100 voices. Furthermore, the toner is attached to the surface of the sleeve as a latent image on the photosensitive drum 1 (a latent image is attached and subjected to development), and the footing on the sleeve is a thin layer, and moreover, the toner is transferred from the sleeve to the drum by electric force. For rounding to effect spatial transition, it is necessary to bring the developing sleeve 1 close to the surface of the drum 5 (600μ in this example) and maintain it constant.
Preferably, an alternating bias voltage is applied between the sleeve and the drum as described in No. 656-9. In order to guarantee such $1K, the external dimensions of the sleeve 1 are required to have mechanical precision on the order of several tens of pitches. Figure 2 shows a cross-sectional view of a conventional sleeve. The magnet roach 2 shown in the figure is misaligned with the sleeve 1.

9 to the 7 flange 10.11 of the sleeve, and the sleeve 1 is connected to the 7 flange 100 of one of the 7 flange 10.
is pivotally supported by the housing 6 of the developing device via a bearing 12. The magnet roller 4 has one end 4 connected to the fixed plate 16.
The change was prevented by

It is fixed to the developing device housing 6 so that the magnetic pole position is constant.

The sleeve 1 receives a drive from a drive source via a gear 14 and rotates. 15 and 16 are spacer rollers that come into contact with the photosensitive drum surface for spacing, and 17 and 18 are bearings 9.
, 12. This is a sealing member for preventing toner from entering into the interior of .

Now, in the developing sleeve configured as shown in Fig. 2, in order to achieve precision such as coaxiality in the outer circumferential direction of the sleeve with respect to the shaft end, a magnetic roller is pushed into the sleeve, and both 7 flanges 10 and 11 are attached to the sleeve. After joining and fixing, the 7 lunge shaft end 10a and one end 4afi of the magnet roach:
Accuracy was achieved by grinding the outer circumferential surface of the sleeve as a reference. In this machining process, since the sleeve contains an internal pressure magnet, a grinding tool made of a magnetic material cannot be brought close to the sleeve, resulting in poor workability and high costs.

Therefore, in the present invention, the above-mentioned drawbacks are solved, and the machining process s'f
To provide a developing sleeve that is simplified, reduces costs, and increases productivity.

FIG. 3 shows a cross-sectional view of the developing sleeve of the present invention.
The magnet roller 19 has its shaft end 19m, 19
b is directly supported and fixed to the housing 6 of the developing device. Sleeve 20! Separately from the Dunnett roller 19, it is rotatably supported in the 8L image holding casing 6 via bearings 21 and 22. 23 and 24 are spacer rods 25 for creating a gap between the photosensitive drum and the 7-lunge, and 26 is a drive gear.

As in the above configuration, since the magnetic roller 19 and the sleeve 20 are supported separately from the housing, the sleeve 20
0 alone can guarantee accuracy. Furthermore, since there is no step of assembling a magnet inside, the processing step is simplified and workability is improved. Furthermore, sealing materials 17 and 18 in the bearings 8 and 9 shown in FIG. 2 for holding the magnet A-2 are also no longer necessary. As described above, according to the present invention, costs can be reduced in terms of processing steps and number of parts, and productivity can be improved.

As shown in FIG. 4 as a modification of the present invention, the structure of the sleeve can be made simpler by covering the outer peripheral surface of the sleeve 20 with rings 27 and 28 having a thickness corresponding to the gap between the photosensitive drum and the sleeve as spacer stiffness. It can also reduce costs. Further, the present invention can be applied to a developing device using a two-component developer as well as one using a one-component developer as shown in FIG.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of our developing device, FIG. 2 is a sectional view of a conventional developing sleeve, FIG. 6 is a sectional view of a developing sleeve according to the present invention, and FIG. 4 is a sectional view of another embodiment of the present invention. It is. In the figure, 6...Developing device housing, 19-...Magnetic roller, 20...■ Sleeve, 23, 24
...L, spacer east roller, 26...gear.

Claims (2)

[Claims] (1) In a developing device having a Madanetto inside the hollow developing sleeve, the above-mentioned M image sleeve! An M image device characterized in that Dunnett--Two can be supported separately from each other in a housing of a developing device. (2) The developing device according to claim 1, wherein the developing sleeve is movably movable, and the magnetic roller is supported by a fixed knee on the developing device housing.