JPH0555160U - Development device - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the lid has a thin wall, the space between the developing roller and the lid is secured to prevent the developer from overflowing. A scraper for scraping used developer on a developing roller, a holder for holding the scraper, a plurality of protrusions installed on the upper portion of the holder, and a plurality of protrusions for the lower surface of a lid of the developing device. And is configured to maintain a distance between the holder and the lid of the thin developing device.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention is intended for image forming apparatus, such as when the developing device that forms a toner image on the photoconductor is adjusted, especially when the carrier in the two-component developer is used up , Developing device contact and attachment / detachment processing.

[0002]

[Prior Art]

 Conventionally, when the distance between the developing roller and the lid of the developing device is narrowed, when the lid is thin, when the external force is applied to the image forming device, the lid is bent and the interval is deformed into an indefinite shape. Sometimes overflowed. If the lid is made thicker or the gap is widened as a countermeasure, a new defect that the shape of the developing device cannot be made compact arises.

[0003]

[Problems to be solved by the device]

 On the one hand, the recent technological trend is to arrange a variety of multiple developing devices for high image quality such as multicolor printing full-color glossy images, and on the other hand, downsize the image forming device body and reduce costs. Was required, and downsizing of the developing unit was inevitable.

Therefore, there is a measure to supply a compact developing device in which the distance between the developing roller and the lid of the developing device is narrow to some extent, and even when the lid is thin, the distance between the developing roller and the lid is maintained. I needed it. The present invention responds to this.

[0005]

[Means for Solving the Problems]

 To provide a compact developing device capable of preventing the developer from overflowing by ensuring the distance between the developing roller and the lid even when the distance between the developing device lid and the developing roller is narrow and the developing device lid is thin. The problem has been solved by disposing a plurality of protrusions on the lower surface of the lid of the developing device, and when the lid of the developing device is fitted to the developing device main body, the protrusions are placed in contact with the roof-like portion above the scraper.

[0006]

【Example】

 FIG. 1 is a cross-sectional view of the developing device 1. The toner supplied from a hopper, which is a toner supply means (not shown), is sufficiently agitated and mixed by the agitating screws 3 and 4. Generally, in both the one-component developer and the two-component developer, the stirring of the developer is to sufficiently frictionally charge the developer. The developer which has undergone such a process is circulated in the developing device by the screws of the stirring screws 3 and 4 which rotate in opposite directions. During this period, a toner concentration sensor (not shown), which is a toner concentration sensor, adjusts the supply of the toner corresponding to the concentration ratio, so that the toner concentration and the constant content ratio between the toner and the carrier are always maintained. The triboelectrically charged and homogenized developer is supplied to the developing roller 2 by the supply roller 5. On the way, the developer formed into a thin layer by the developer thinning roller 6 is conveyed by the rotation of the developing roller 2 in the direction of the arrow, and is opposed to the developing roller 2 with a minute gap in the developing area. The latent image on the photoreceptor shown in the figure is subjected to non-contact reversal development. During this non-contact development, a developing bias in which an alternating current component is superimposed on a direct current component is applied, and as a result, as for the developer on the developing roller 2 at the developing contact portion, only toner is selectively transferred to the latent image. Adhere to the surface of the image. The used developer after completion of the development is peeled off by the scraper 7 held by the holder 10, and is held by the projections 9 arranged at a plurality of portions on the lower surface of the lid of the developing device. And the holder 10 to pass through the gap and be transported so as to be mixed with the newly supplied developer to prepare for the next development.

FIG. 2 is a perspective view in which the lid 11 of the developing device is turned upside down. Protrusions 12, 13 and 14 are provided on the lower surface of the lid of the developing device, and hold a space between the holder and the lid of the developing device. Thus, the space between the developing roller and the lid is maintained. FIG. 3 is a sectional view of the developing device lid, 15 is the developing device lid, and 16 is the projection. In FIG. 4, 17 is a scraper, 18 is a holder for holding the scraper, and 18A is a smooth shape at the top of the holder, and the above-mentioned projections 12, 13, 14, 16 are in contact with the developing device so that the developing device The lid 8 is fitted into the main body of the developing device. The protrusions are made of plastic, for example, and can be strips with a thickness of about 1 mm as shown in FIGS. 2 and 3, so that the volume inside the developing device is almost unchanged, and the developing roller 2 and the developing device lid 8 are Can maintain a constant interval. Further, due to the recent technical demand for downsizing, the developing device lid 8 is made thin, and the space between the developing roller 2 and the developing device lid 8 is narrowed to achieve a compact size. We are responding to requests. Along with this, the external force applied to the developing device such as gripping and attaching / detaching for maintenance etc. corresponds to the conventional device collectively, but in the present invention, each of the above-mentioned protrusions divides the total pressure of the external force into a plurality of parts. Further, since each partial pressure is dealt with, it is possible to provide a device having reinforced strength, in which it is unlikely to cause shaving or distortion due to the external force. As a result, the disadvantages of the conventional apparatus, such as the thin lid being sluggish and the gap being unable to be secured, and the developer overflowing, are overcome.

[0008]

[Effect of the device]

 By using the method of the present invention, it is possible to maintain a constant gap between the developing roller and the lid, even when using a lid such as a thin wall that is insufficient in strength and sufficient to maintain a precise shape. Even if an external force is applied to the developing device, the developer can be prevented from overflowing due to the flexible deformation of the lid, and the developing device can be made compact.

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device.

FIG. 2 is a rear perspective view of the lid of the developing device.

FIG. 3 is a sectional view of a lid of the developing device.

[Fig. 4] Illustration of the present invention

[Explanation of symbols]

 1 Developing Device 2 Developing Roller 3 Stirring Screw 4 Stirring Screw 5 Supply Roller 6 Developer Thinning Roller 7 Scraper 8 Developer Lid 9 Protrusion 10 Holder 11 Developer Lid 12 Protrusion 13 Protrusion 14 Protrusion 15 Developer Lid 16 Protrusion 17 Scraper 18 Holder 18A Top of holder

Claims (1)

[Scope of utility model registration request] 1. A developing device having a developing roller and a lid of the developing device, wherein a projection for maintaining a distance between the developing roller and the lid of the developing device is arranged on a lower surface of the lid of the developing device. Developing device.