JPH0444068A - Developing unit of electrophotographic recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic recording device that records characters and patterns on paper based on the principles of electrophotography. Particularly regarding improvement of the developing unit - [Prior Art] Fig. 6 shows a side view of a conventional developing unit.

As shown in the figure, the developing sleeve for supplying the developer, ie, toner, accommodated in the toner accommodating portion 104 to the image bearing member, ie, the photosensitive drum 106, includes a magnetic member 102 having a rotatable magnetic pole; It was formed by a rotatable metal sleeve 101.

By rotating the metal sleeve 101 and rotating the magnetic member 102 at a speed three to five times the rotation, the toner is charged and transported, and a certain gap d is maintained between the metal sleeve and the photosensitive drum. I have been developing toner.

[Problems to be Solved by the Invention] The conventional developing unit as described above has a
Even in a relatively low-speed machine of 20 m, the metal sleeve is
0 r pm to 300 rpm, the magnetic member 102
It is necessary to rotate at a relatively high speed of about 00 to 200 rpm, and the drive system becomes complicated and large due to the increase in torque.
Furthermore, printing quality deteriorates due to scattering and fogging of the 1-ner due to high-speed rotation, and density fluctuations occur due to instability in the amount of charge of the 1-ner.

In such a developing unit 1-, the magnetic member 10
It is necessary to polish the outer diameter of the metal sleeve 10 and to arrange the 5R member 102 accurately with a small gap between the metal sleeve 7101 and the metal sleeve 7101, which increases the number of man-hours and costs. It became. In addition, magnetic members】02
Since there are many components of the developer unit 1-, such as the metal sleeve 101, the metal sleeve 101, and reservoir parts that support each component, it has been impossible to miniaturize the developer unit.

In addition, there have also been proposals to eliminate the developer transporting member and transport the developer using a magnetic material or rollers, such as Japanese Patent Application Laid-open No. 63-223675 and US Pat.
851.874, image deterioration due to oxidative corrosion (so-called rust) of the 6tN material, and when developing in contact with the photoreceptor belt or photoreceptor drum, for example, if the photoreceptor material is OPC. In the case of organic photoreceptors such as those used in organic photoreceptors, the magnetic material has a relatively higher hardness than the photoreceptor material, so there is a problem in that it scratches the photoreceptor material and causes fatal defects in the image. are doing.

As described above, there are problems in that it is impossible to miniaturize the developing device, and that image quality deteriorates and defects occur. An object of the present invention is to solve these problems and provide a small-sized developing device with stable print quality.

[Means for Solving the Problems] In order to achieve the above object, the developing unit of the present invention has a developing sleeve in which an elastic member is disposed on the outer peripheral surface of a magnetic member.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a section showing the structure of a developing sleeve according to the present invention. A 1ift member 2 with magnetic poles arranged on the outer periphery of the 8 rod 3 is disposed, and an elastic member 1 is disposed on the outer periphery of the Ii1'l-j main member 2.

FIG. 2 shows a state in which the developing sleeve is disposed within the 1-chi storage section 4. As shown in FIG. Developing was performed with the doctor blade 5 fixed so as to be in contact with the outer peripheral surface of the developing sleeve. A latent image was formed on the photoreceptor drum 6 by a light generating unit, and when a bias voltage was applied to the eight rods 3, one henna image was formed on the photoreceptor drum 6. Since the developing sleeve and the photosensitive drum 6 rotated at a constant speed, a good image without 1-ner scattering could be obtained. In addition, the photosensitive drum 6
Since the developing sleeve is in contact with the developing sleeve, the nip width at the developing position can be increased, so that the development opportunity can be increased, resulting in improved development density and uniformity. Furthermore, due to friction caused by contact between the photoreceptor drum 6 and the developing sleeve,
It was also confirmed that the developing sleeve rotates in accordance with the rotation of the photosensitive drum 6, and that it is also possible to eliminate the gear train of the developing sleeve. The experiment was conducted under the same conditions as the embodiment shown in FIG. 2 above, except that the rotational speed of the developing sleeve was increased and the peripheral speed was made faster than the peripheral speed of the photosensitive drum 6. As a result, an image with high -layer development density could be obtained. Further, even if the rotational speed was increased by a certain amount, no scratches were observed on the photosensitive drum 6 due to the effect of arranging the elastic body on the outer circumferential surface of the developing sleeve.

FIG. 3 shows a state in which the developing sleeve is separated from the photosensitive drum 6 by a gap d. In this state, when the developing sleeve was rotated at the same speed as the photosensitive drum 6 to perform development, it was found that although the developed density was lower than that shown in FIG. A high-quality image was obtained. In other words, the toner is uniformly charged due to the contact between the elastic member 1 and the doctor blade 5, and the toner is formed into a thin layer on the developing sleeve, indicating that the charging and toner conditions are stable. If the developed density is low, there are measures to increase the developed density by using a highly chargeable toner, increasing the number of revolutions of the developing sleeve, etc. This time, I tried increasing the rotation speed of the developing sleeve, and was able to increase the developed density. In this experiment, 1. An Oppm machine was used. The photosensitive drum has a diameter of 30 mm and a rotation speed of about 37 rpm, and in the embodiment shown in FIG. 2, the developing sleeve has a diameter of 20 mm, so the rotation speed of the developing sleeve is about 56 rpm. In the embodiment shown in FIG. 3, there is a good range for the current T-sleeve between 70 and 801 pm, and the speed is lower than in the conventional example.Of course, the optimum range varies depending on the toner and printing speed. Both Fig. 2 and Fig. 3] For henna, use an insulating magnetic l-component toner, and perform the henna with a gap d of 02 to 0.5 mm.The 8 rods 3 of the developing sleeve are φ6 mm, and the fin member 2 is φ6 mm, φ18.
3f of m+n, φ1.9mm! l! using elastic member 1
There were three types of thickness: 2 mm, ], mm, and 0.5 mm, and the developing sleeve diameter was 20 mm.

Of course, the above experimental conditions are not limited, and vary depending on the diameter of the developing sleeve and photosensitive drum, circumferential speed, physical properties, printing speed, etc. In addition, the methods shown in FIGS. 4 and 5 were also tried for the second part of the contact of the doctor blade 5. In FIG. 4, a stiffener 7 is arranged behind the doctor blade 5 so that the doctor blade 5 applies a uniform load to the elastic member. However, in the case of FIG. 4, there are problems such as an increase in the number of parts, so as shown in FIG. 5, a doctor blade 5 made of an elastic material is used for contact. 1- If managing the contact pressure between the lid blade 5 and the elastic member 1 takes time and effort, measures such as those shown in FIGS. 4 and 5 are appropriate. In this embodiment, the 8 rods 3 are made of iron, but they may be made of other metals or plastics that can conduct, or other conductive means such as pressing an electrode on a magnetic member. If I can get it, I don't mind the materials. The magnetic member 1 disposed on the outer peripheral surface of the 8 rod 3 is made of ferrite, alnico, manganese aluminum, or atomic number 58 to 71 (element symbol Ce).
-L u ), among them Nd, P
It is possible to use a rare earth magnet in which at least one of the 3D transition metals represented by Fe, Ni, and Co is added to at least one of the rare earth elements represented by r and Sm.

In addition, the elastic member 3 disposed on the outer circumferential surface of the &n material 1 is
Considering the contact area (so-called nip) between the photoreceptor drum 6 and the elastic member 1, the contact pressure with the doctor blade 5, and the occurrence of scratches due to contact with the photoreceptor drum 6, Hs
Rubber materials of about 10 to 90 are desirable, such as butyl rubber, acrylic rubber, urethane rubber, silicone rubber, fluororubber, polysulfide rubber, ethylene-propylene rubber, Hypalon, ethylene-vinyl acetate rubber, chlorinated polyethylene,
Alphine rubber, polyester rubber, epichlorohydrin rubber, natural rubber, inbrene rubber, styrene rubber, nitrile rubber, butadiene rubber, chloroprene rubber, etc. are suitable. Further, when considering the transportation of toner, the elastic member 1 may be provided with a thickness such that an liR flux density of 200 GAUSS or more can be obtained on the surface of the elastic member.

In the examples shown in Figures 2 and 3, 30°C, 160%RH
When images equivalent to 10,000 sheets were continuously formed under the following environment, the resulting images were high-quality, high-resolution, high-density images similar to the first printed sheet. For comparison, 6R
Because there is no elastic member on the outer periphery of elastic member 2, 1 is shown in Fig. 2.
Image formation was performed using a configuration similar to that shown in FIG. 3 (comparative experiment (■)). In the configuration shown in FIG. 2, the photoreceptor drum 6 is immediately scratched, causing a fatal defect in the image, and in the configuration shown in FIG. When the toner was removed and the top of the magnetic member 2 was observed, the occurrence of rust was confirmed, confirming the effect of providing the elastic member. In addition, an experiment (comparative experiment ■) similar to the above comparative experiment ■ was conducted except that the elastic member 1 was not used and the magnetic member 2 contained an elastic material such as rubber (comparative experiment ■). , if it comes into contact with the photoreceptor drum 6
Magnetic member 2 immediately scratches and prints 0 after 10,000 sheets.
Rust was observed on the surface. In other words, it has been found that even if an elastic material is included, a problem occurs because a magnetic material, which is a metal and has a higher hardness than a photosensitive material such as OPC, is exposed on the surface.

In addition, in the case of a developing unit in which the photosensitive drum 6 and the developing sleeve are in contact with each other to perform development, as in the embodiment shown in FIG. This caused the problem of low-temperature soil retention.

However, in this embodiment, the magnetic member 2 is arranged, and its 61'
Since the toner can return to the developing sleeve side by i-force, printing was carried out in an environment of 10° C. and 30% RH, but no low-temperature force blur occurred.

[Effects of the Invention] Since the present invention is provided with a developing sleeve in which an elastic member is arranged on the outer circumferential surface of a magnetic material in the developing unit, it is possible to reduce 1 herk by lowering the speed, simplify the mechanism, and improve density and print quality. It is possible to provide a stable, high-quality, and compact developing device.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of the present invention. FIGS. 2 to 5 are cross-sectional views of a developing sleeve disposed in a developing unit. FIG. 6 is a cross-sectional view showing a conventional developing unit. Elastic member / Magnetic member / 8 rods Toner storage section / Doctor blade Photoconductor drum splash Metal sleeve Magnetic member Toner storage section Photoconductor drum Applicant Seiko Epson Corporation Agent Patent attorney Kizobe Suzuki (1 other person) 11 7: Zen, 1 Tsubakifu 4 Nido →--1 Matamaisho 5: Doctoroff, Rude

Claims (1)

[Claims] In a developing unit of an electrophotographic recording apparatus, the developing unit includes a storage section for storing a developer and a developing sleeve that rotates and supplies the developer stored in the toner storage section to an image carrier unit, wherein the developing sleeve comprises: A developing unit for an electrophotographic recording apparatus, comprising a magnetic material and an elastic member disposed on the outer peripheral surface of the magnetic material.