JPH04295871A - One component magnetic toner developing device - Google Patents

Abstract

PURPOSE:To solve an after image phenomenon and to prolong a life in a one component magnetic toner developing device. CONSTITUTION:A projecting and recessed line R2 in parallel with the circumferential direction of a sleeve 2 is formed on the surface of the sleeve 2, and a scraper 11 for scraping toner 6 is elastically provided on the toner removing side of the sleeve 2. Since the toner which is left without being used in developing and adheres to the sleeve 2 is completely scraped by the scraper 11, the electrostatically charged amount of the toner 6 is uniformized and the after image is prevented from occurring. The shaving of the sleeve 2 by the scraper 11 is a little and the one component magnetic toner developing device whose life is long is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for electrophotographic printers and copying machines, and more particularly, to a developing device using monocomponent magnetic toner.

0002

2. Description of the Related Art In recent years, with the rapid expansion of the market for non-impact printers and personal copying machines, there has been an increasing need for a one-component magnetic toner development system that is easy to maintain.

[0003] The configuration of a conventional developing device using one-component magnetic toner (hereinafter referred to as developing device) is shown in FIG.
This will be explained with reference to.

As shown in the figure, 1 is a fixed magnet roll with a plurality of magnets arranged inside, 2 is a sleeve that rotates around the fixed magnet roll 1, and 3 is a sleeve 2 containing one-component magnetic toner 6 (hereinafter referred to as , referred to as toner); 4 is a magnetic blade that regulates the layer thickness of the toner adhering to the sleeve 2; 5 is a photosensitive drum; 7 is a power source that applies an alternating voltage between the sleeve 2 and the photosensitive drum 5; It is.

In the above structure, the toner 6 stored in the developer container 3 is drawn onto the sleeve 2 by the magnetic force of the magnet roll 1. The toner on the sleeve 2 is charged to a predetermined polarity by friction caused by the rotation of the sleeve 2. Since the toner 6 contains a charge control agent, the toner is charged to a stable amount. The toner 6 is then conveyed by the rotating sleeve 2 and reaches the magnetic blade 4. During this conveyance, sandblasting is applied to the surface of the sleeve 2 in order to improve the conveyance force of the toner 6, to form a uniform and even thin toner layer, and to impart sufficient charge to the toner 6 through friction with the sleeve 2. It has been processed. A magnetic pole N1 of a magnet is arranged opposite the magnetic blade 4, and the toner 6 is regulated to a constant layer thickness by the magnetic field generated between the blade 4 and the magnetic pole N1 and the gap between the blade 4 and the sleeve 2. be done. Toner 6 with regulated layer thickness
is conveyed to the photosensitive drum 5 by rotation of the sleeve 2. The toner layer facing the photosensitive drum 5 stands up due to the magnetic force of the developing magnetic pole S1, and the electrostatic latent image on the photosensitive drum 5 and the sleeve 2
The photosensitive drum 5 is moved back and forth by the effect of a low frequency alternating electric field from a power source 7 applied between the photosensitive drum 5 and is attached only to a portion corresponding to the electrostatic latent image on the photosensitive drum 5. The toner 6 on the sleeve 2 remaining undeveloped is conveyed into the developer container 3 by the rotating sleeve 2 and the magnetic force of the conveying magnetic poles N2 and S2, and is removed from the sleeve 2.

[0006]

[Problems to be Solved by the Invention] In the developing device having such a conventional configuration, since the uneven surface formed by sandblasting on the sleeve 2 is an irregular surface, the toner 6 remaining after development is washed away from the top of the sleeve 2. The toner 6 is conveyed by the rotating sleeve 2 without being sufficiently removed, reaches the magnetic blade 4 again, and repeats the same cycle. Therefore, new toner is added to the surface of the sleeve 2 where the toner 6 that was developed on the photosensitive drum 5 in the previous cycle has disappeared. Since the adhering toner 6 differs in the amount of charge from the toner 6 on the side where development remains, there is a problem in that an afterimage from the previous cycle occurs. This tendency is particularly noticeable in halftone images, causing the images to become unclear and unsightly.

In order to solve this problem, it has been considered to provide a scraper in contact with the sleeve 2 to scrape off the undeveloped toner 6, but with this configuration, the sleeve 2
Even if a polyester film or the like is attached to the scraper to prevent damage to the sleeve 2, the sandblasted surface of the sleeve 2 will be scraped by the scraper, resulting in a problem that the life of the developing device will be significantly shortened.

The present invention solves the above problems and makes it possible to form a uniformly charged thin layer of developer on a developer support member, and also to sufficiently remove toner remaining after development, thereby eliminating afterimages. It is an object of the present invention to provide a one-component magnetic toner developing device that does not cause generation.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a sleeve that holds monocomponent magnetic toner while rotating and conveying it to supply it to a photosensitive drum; a fixed magnet; a magnetic blade disposed with a gap between the surface of the sleeve and regulating the thickness of the one-component magnetic toner; Rz=1.5~
In addition to forming an uneven surface having a diameter of 6.0 μm, a scraper for removing toner remaining after development is brought into elastic contact with the one-component magnetic toner removal side of the sleeve along the rotational direction of the sleeve.

0010

[Operation] With the above-described structure, the present invention has a surface roughness Rz of 1.5 to 6.0 μm parallel to the circumferential direction of the sleeve surface.
In addition to forming unevenness in the axial direction, a scraper for removing undeveloped toner is brought into elastic contact with the side of the sleeve from which one-component magnetic toner is removed, along the direction of rotation of the sleeve. However, since it is smooth in the circumferential direction, the toner remaining after development can be sufficiently scraped off with a scraper, and toner transportation and frictional charging can be stabilized.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

[0012] The same parts as those shown in the conventional example are given the same reference numerals and their explanations will be omitted.

As shown in FIG. 3, the surface of the sleeve 2 has a surface roughness Rz of 1.5 μm to 6.0 μm parallel to its circumferential direction.
A roughness Rz having a diameter of μm is formed.

Further, a scraper 11 is elastically contacted on the toner removal side of the sleeve 2 along the direction of rotation of the sleeve 2. A slippery and wear-resistant sliding member 12 made of polyester film or the like is attached to the contact portion of the scraper 11 with the sleeve 2.

In the above structure, the operation from the time when the toner 6 is supplied from the developer container 3 to the sleeve 2 until the toner 6 is attached from the sleeve 2 to the photosensitive drum 5 is the same as that of the conventional example, so a description thereof will be given below. Omitted.

The toner 6 remaining on the sleeve 2 after development is scraped off from the sleeve 2 by the scraper 11 and falls into the developer container 3.

In this scraping, since the unevenness Rz formed on the sleeve 2 is formed in the circumferential direction of the sleeve 2, the toner 6 is easily scraped off, and the toner remaining after development on the sleeve 2 is sufficiently removed. can do.

Furthermore, since a sliding member 12 is attached to the contact portion of the scraper 11 with the sleeve 2, the sleeve 2
can reduce wear and tear.

Here, the surface of the sleeve 12 is formed with an unevenness Rz as shown in FIG. 3, and the unevenness Rz is carved so as to repeat the unevenness sequentially in the axial direction of the sleeve.

If the surface roughness of the sleeve 2 is too smooth, the conveyance force of the toner 6 will be insufficient, and in particular, if the fluidity of the toner 6 is reduced or agglomeration occurs, the toner layer on the sleeve 2 will be damaged. There will be unevenness in the thickness, and unevenness will also occur in the microscopic image, making it impossible to obtain a good image. Furthermore, if the roughness is too rough, the toner 6 will fuse onto the sleeve 2 and appear as black streaks on the image.

From the above points, as a result of experiments, it was confirmed that the surface roughness Rz of the sleeve 2 is preferably 1.5 to 6.0 μm.

As described above, according to the one-component magnetic toner developing device of the embodiment of the present invention, the surface of the sleeve 2 is provided with unevenness having a surface roughness Rz of 1.5 to 6.0 μm parallel to the circumferential direction. At the same time, a scraper 11 for removing the toner remaining after development is brought into elastic contact with the side of the sleeve 2 from which the toner 6 is removed along the rotational direction of the sleeve 2, thereby removing the toner 6 remaining after the development from above the sleeve 2. It can be scraped off sufficiently. As a result, in the next cycle, development is performed using the toner 6 newly deposited on the sleeve 2 and having a uniform charge amount, so that there is an effect that the occurrence of an afterimage can be eliminated. Further, since the surface of the sleeve 2 has irregularities in the axial direction but is smooth in the circumferential direction, it is less likely to be scraped by the scraper 11, and the life of the developing device can be extended.

[0023]

As is clear from the above description of the embodiments, according to the present invention, the surface of the sleeve is provided with unevenness having a surface roughness Rz of 1.5 to 6.0 μm parallel to the circumferential direction. At the same time, the scraper for removing the toner remaining after development is brought into elastic contact with the side of the sleeve where the toner is removed along the rotating direction of the sleeve, making it possible to sufficiently scrape off the toner remaining after development from the top of the sleeve. can. As a result, in the next cycle, development is performed using toner that has newly adhered to the sleeve and has a uniform charge amount, so that it is possible to eliminate the occurrence of afterimages. In addition, since the sleeve surface is uneven in the axial direction but smooth in the circumferential direction, it is less likely to be scraped by the scraper and the life of the developing device can be extended.This is an excellent one-component magnetic toner developer. equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a one-component magnetic toner developing device according to an embodiment of the present invention.

[Figure 2] Enlarged side view of the main parts

[Fig. 3] (a) is a plan view of the sleeve. (b) is an enlarged front sectional view of the Rz section shown in Fig. 3(a).

[
Figure 4: Side sectional view of a conventional one-component magnetic toner developing device

[Explanation of symbols]

1 Fixed magnet roll 2 Sleeve 3 Developing container 4 Magnetic blade 5 Photosensitive drum 6 Toner 7 Power supply 11 Scraper 12 Sliding member

Claims (2)

[Claims] Claims: 1. A sleeve that holds one-component magnetic toner while rotating it and supplies it to a photosensitive drum, a plurality of fixed magnets disposed inside the sleeve, and a gap between the surface of the sleeve. and a magnetic blade disposed to regulate the thickness of the one-component magnetic toner, the sleeve having a surface roughness parallel to its circumferential direction Rz=1.5 to 6.
．． A one-component magnetic toner developing device, in which an uneven surface having a diameter of 0 μm is formed, and a scraper for removing undeveloped toner is in elastic contact with the one-component magnetic toner removing side of the sleeve along the rotational direction of the sleeve. 2. The one-component magnetic toner developing device according to claim 1, wherein an alternating electric field is applied between the sleeve and the photosensitive drum.