JPH01277869A - Developing device - Google Patents

Abstract

PURPOSE:To stabilize the gap between a developing roller and a photosensitive body and to prevent toner from leaking by fitting guide caps onto no-image parts on both end sides of a developing roller except its contact part for an elastic material blade, and providing seal members between the guide caps and elastic material blade. CONSTITUTION:The guide caps 40 and 40 are fitted onto the no-image parts 34a on both end sides of the developing roller 34. Here, the guide caps 40 and 40 are made to abut on the no-image parts 10a of a photosensitive body 10 and thus the gaps G between the photosensitive body 10 and developing roller 34 is adjusted; and the seal members 41 and 41 are provided between the guide caps 40 and 40 and elastic material blades 35. Consequently, the invariably stable gap G can be maintained and no developer leaks from a developing device main body.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a developing device installed in an image forming apparatus such as an electronic copying device, and particularly relates to a developing device equipped with an image forming apparatus such as an electronic copying device, and particularly relates to a developing device equipped with an image forming apparatus such as an electronic copying device. The present invention relates to a developing device that maintains a stable gap between the developing device and prevents developer from leaking from the developing device main body.

(Prior Art) In general, a developing device in an image forming apparatus such as an electronic copying device includes, for example, a developing processing means for visualizing an electrostatic latent image formed on a drum-shaped photoreceptor that is an image bearing member. Those using two-component or magnetic-component developers are known.

However, in the two-component development processing means described above, it is necessary to accurately control the concentration ratio of the toner, which is the developer, and the carrier.On the other hand, in the magnetic-component development processing means, the toner contains a magnetic material. Because of this, it not only has disadvantages such as difficulty in colorization, but also requires a magnetic roller as a developing roller, which is a developer holding member, which is extremely costly in terms of cost. It is expensive.

Therefore, in order to solve the above-mentioned problems, a development processing means using a non-magnetic component 1-ner has recently been proposed.

In such a conventional developing device, as shown in FIG. 4, a toner cartridge b containing non-magnetic component toner T is loaded into the upper part of the rear unit of the developing device main body a, and the toner cartridge b is The supplied toner T is supplied to a developing roller e that is pivotally supported within the developing device main body a through an agitation roller C that is a developer conveying member and a toner supply roller d made of sponge, and the surface of this developing roller e is An elastic blade f forming a toner layer of a predetermined thickness is brought into contact with the developing roller e.
The toner T that has passed through the contact area with the toner T is coated in a thin film layer with a thickness of 30 μm and is deposited on the developing roller e, while a minute gap G is left between the developing roller e and the drum-shaped photosensitive image carrier is The electrostatic latent image on the photoreceptor g is developed by placing the body g close to the photoreceptor g in a non-contact manner.

Incidentally, in the above configuration, a negative polarity photoreceptor is used, and therefore a positively charged one is used so that the amount of charge of the toner after coating is approximately +12 μC/g. Also.

The gap G between the photoreceptor g and the developing roller e is 2, for example, 30
The photoreceptor potential is set to 0 μm, the photoreceptor potential is -500μ, the developing roller e has a frequency of 2K)lx, and an effective value of 670V.
A superimposed voltage of an AC voltage of -200 V and a DC voltage is applied.

(Problem to be Solved by the Invention) [,2 However, such a developing method basically uses a high-resistance non-magnetic component toner, and the charging of the toner T is caused by the difference between the toner T and the developer. This is done by frictional charging between the roller e and the elastic blade f, and the toner T
The conveyance of the toner is also caused by the mutual electrostatic attraction between the toner T and the developing roller 8, and the toner rotates as the developing roller e rotates, but the driving force is transmitted between the developing roller e and the photoreceptor g on one side. Since the developing roller e and the photoreceptor g are easily twisted together, the axial gap G varies, which has a negative effect on the density of the developed image. However, as shown in FIG. 5, there is a problem in that toner easily leaks from gaps in the vicinity of the non-image areas on both ends of the developing roller e, where the elastic blade f does not come into contact, as shown by the arrows, resulting in staining.

The present invention has been made in view of the above circumstances, and its purpose is to stabilize the gap between the developing roller and the photoreceptor and to reliably prevent toner leakage. An object of the present invention is to provide a developing device as described above.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention meshes an image bearing member with a quick-acting gear and a balance gear in which developing rollers are provided at both ends of each other. The developing roller is positioned and driven in a non-contact state with a predetermined gap therebetween, and guide caps are fitted into non-image areas on both ends of the developing roller excluding the contact area of the elastic blade, and the guide cap and the A sealing member is provided between the elastic blade and the elastic blade.

(Function) That is, by having the above configuration, the present invention has the following features:
Both ends of the image carrier and the developing roller are engaged with each other by gears, and
Since the guide caps are interposed in contact with each other's non-image areas, twisting between the image carrier and the developing roller during heel movement is prevented, a stable gap is always maintained, and the developing unit body No leakage of developer occurs.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings shown in FIGS. 1 to 3.

FIG. 3 shows the internal structure of an electrophotographic image forming apparatus equipped with a developing device according to the present invention, and numeral 1 in the figure is the main body of the copying machine. A paper feed cassette 2 that can automatically or manually feed paper is installed on the right side of the copying machine main body 1, and a paper output tray 3 is installed on the left side of the main body 1, and a document (not shown) is placed on the left side. On the upper surface g
is provided.

A drum-shaped photoreceptor 10 serving as an image carrier is arranged approximately in the center of the copying machine main body 1 so that it can be rotated in the direction of the arrow in synchronization with the document table 4 by a drive mechanism (not shown). The photoreceptor 10 is uniformly charged by a charging charger 11 and transmits an original image irradiated by an exposure lamp 12 to a focusing light transmitting member (product name: SELFOC lens array) 13 constituting an optical system device. to form an electrostatic latent image on the photoreceptor 1o, and a developing device 14 (to be described later) supplies and adheres non-magnetic component toner T to this electrostatic latent image to develop the image ( below,
A toner image) is sent to the transfer charger 15 side.

The above-mentioned transfer charger 15 transfers the copy paper P made of plain paper as recording paper fed from the paper feed cassette 2 which is automatically or manually fed via the paper feed roller 16 and the pair of aligning rollers 17 and 17. After the transfer, the copy paper P is peeled off from the photoreceptor 10 by a peel charger 18 using AC corona discharge, passed through a conveyance path 19, the toner image is melted and fixed by a fixing device 2o, and then discharged. The paper is discharged onto the paper discharge tray 3 by roller pairs 21 and 21.

On the other hand, the residual toner on the photoreceptor 10 after the toner image is transferred to the copy paper P and peeled off is cleaned by the cleaning blade 23 of the cleaning device 22, and then
The electric potential on the photoreceptor 10 is brought down to a certain level or less by the static elimination lamp 24 to make the next copying operation possible.

That is, in the developing device 14 according to the present invention, as shown in FIG. The toner supplied from the toner is supplied to the developing roller 34 which is pivotally supported on the front unit side via the stirring roller 32 and the toner supplying roller 33 made of sponge.
An elastic blade 35 that forms a toner layer with a predetermined thickness is brought into contact with the surface of the toner T, and the toner T that has passed through the contact area between the elastic blade 35 and the developing roller 34 is coated into a thin film layer with a thickness of 30 μm. By attaching it to the developing roller 34 and leaving a small gap G in the developing roller 34, the photoreceptor 10 is configured to be located close to the developing roller 34 in a non-contact state.

The electrostatic latent image on the photoreceptor 10 is developed.

As shown in FIG.
The drive gear 101 provided at the rear end of the developing roller 34 and the balance gears 342 and 102 provided at the front end of the photoreceptor 10 mesh with each other. 101 is transmitted to a gear 301 provided on the developing unit main body cover 30a,
In addition, a drive gear 331 on the rear side of the toner supply roller 33
On the other hand, a gear 301 provided on the developer main body cover 30a meshes with an idler gear 36 that meshes with a drive gear 321 provided on the rear side of the stirring roller 32, so as to drive the stirring roller 32. This is what has become.

Furthermore, non-image areas 34a on both end sides of the developing roller 34
A guide cap 40.4o is fitted therein, and by bringing these guide caps 40.40 into contact with the non-image area 10a of the photoreceptor 10, the gap between the photoreceptor 1o and the developing roller 34 is reduced. G to guide cap 40.
The gap can be adjusted to maintain a gap of, for example, 300 μm depending on the thickness of the guide cap 40.40, and a sealing member 41.41 is provided between the guide cap 40.40 and the elastic blade 35. Part 41.4
1, non-image portions 34a on both ends of the developing roller 34;
This is designed to prevent toner from leaking from the gap near 34a.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the above description, according to the present invention, a drive gear and a balance gear, each having a developing roller provided at both ends of an image carrier, are meshed with each other to form a predetermined gap. Positioning is driven in a non-contact state, and guide caps are fitted to non-image areas on both ends of the developing roller excluding the contact areas of the elastic blade, and a seal is provided between the guide cap and the elastic blade. Since the structure includes a member, it is possible to prevent twisting between the image carrier and the developing roller during driving, and it is possible to maintain a stable gap at all times. Accordingly, it is possible to provide a developing device having an excellent effect that no leakage of the agent occurs.

[Brief explanation of the drawing]

FIG. 1 is a schematic exploded perspective view showing an embodiment of the developing device according to the present invention, FIG. 2 is a schematic plan view of essential parts showing the meshing state of the quick-acting portion of the image carrier and the developing roller, FIG. 3 is an explanatory diagram schematically showing the internal structure of an electrophotographic copying machine as an image forming apparatus equipped with the developing device of the present invention;
The figure is a schematic explanatory diagram of a conventional developing device, and FIG. 5 is an explanatory diagram schematically showing the state of toner leakage from the vicinity of the non-image area of the conventional developing roller. DESCRIPTION OF SYMBOLS 1... Image forming apparatus, 10... Image carrier (drum-shaped photoreceptor), 10a...
Non-image part. 101... Drive gear, 102... Balance gear. 14...Developing device. 30... Developing device body, 34... Developing roller. 34a... Non-image portion, 341... Drive gear. 342... Balance gear, 40.40... Guide cap, 41.41... Seal member. G...Gap, T...Developer (toner).

Claims (1)

[Claims] A developing roller is positioned on the image carrier in a non-contact state by meshing a driving gear and a balance gear provided at both ends of the developing roller with a predetermined gap, and the contact portion of the elastic blade of the developing roller is A developing device characterized in that guide caps are fitted into the non-image portions on both ends except for the non-image portions, and a sealing member is provided between the guide caps and the elastic blade.