JPH0594093A - Electrophotographic recording device - Google Patents

Abstract

(57) [Abstract] [Purpose] The developer remaining on the photoconductor is recovered by the developing device to improve the utilization efficiency of the developer and prevent the deterioration of the charging property of the developer due to the paper dust. It is possible to record. A developing device includes, for example, a hopper 70 that stores toner, a developing roller 40 that is disposed in contact with the photosensitive drum 1, carries the toner that is stored in the hopper 70, and rotates to contact the photosensitive drum 1. A rotating peeling roller 73, which is disposed in contact with the developing roller 40 in a state where at least a part thereof is located inside the hopper 70, and the peeling roller 7
A power source 41 for generating a predetermined electric field between the developing roller 40 and the developing roller 40; and a cleaning blade 74 disposed inside the hopper 70 so as to abut the peeling roller 73 for scraping off the substance adhering to the peeling roller 73. It is configured to include.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording apparatus for recording an image in a process similar to the electrophotographic recording process.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic recording apparatus, a developer (toner) remaining on a photoconductor without being completely transferred onto a recording paper is cleaned by scraping it off with a blade.

By the way, the toner thus scraped off is collected and discarded. In this way, the amount of toner to be discarded reaches about 15 to 25% of the total toner consumption amount, and the utilization efficiency of toner is very poor.

Therefore, there is a cleanerless system in which toner is collected by a developing device and reused. FIG. 2 is a diagram showing the configuration of this cleanerless type electrophotographic recording apparatus. In the figure, 1 is a photosensitive drum. A charging device 2, an exposure device 3, a developing device 4, and a transfer device 5 are arranged around the photosensitive drum 1, and a well-known electrophotographic process (charging, exposure, development, transfer) is performed by these, and a recording sheet is formed. An image is recorded on P.

By the way, the toner attached to the photosensitive drum 1 by the developing device 4 is transferred to the recording paper P by the transfer device 5, but the toner remains on the photosensitive drum 1 as described above. In this way, the toner remaining on the photosensitive drum 1 is dispersed by the brush 6 as the toner mass is destroyed. After this, the charging and exposure device 3 by the charging device 2
Exposure is performed. At this time, toner adheres to the photosensitive drum 1, but since the toner is diffused and its density is low as described above, this charging and exposure can be sufficiently performed without being significantly affected by the toner. Therefore,
When the photosensitive drum 1 reaches the position facing the developing device 4, for example, the unexposed portion is −500V and the exposed portion is −50V, which is almost the same as the potential condition when the residual toner is removed by the cleaning device. Is becoming

In this state, a developing bias of, for example, -200 V is applied to the developing roller 40 of the developing device 4 in order to selectively attach toner (negatively charged) only to the exposed portion of the photosensitive drum 1. Since the power is applied from the power source 41, of the toner that remains on the photosensitive drum 1 in the previous development and remains on the non-exposed portion, the photosensitive drum 1 side is -500V, and the developing roller 40 side is -500V. Since the developing roller 40 has a lower potential of 200 V and the developing roller 40,
Is sucked into.

Thus, the toner remaining on the photosensitive drum 1 is collected by the developing device 4. Since the toner thus collected is used in the subsequent developing operation, no waste toner is generated.

However, the recording paper P is attached to the photosensitive drum 1.
Since the paper dust and the like adheres to the photosensitive drum 1 as described above.
When the toner remaining on the developing roller 40 is collected by the developing device 4, paper dust also adheres to the developing roller 40. The toner is triboelectrically charged while being carried by the developing roller 40 and being conveyed. When the paper powder adheres to the developing roller 40 in this manner, the triboelectric charging property is deteriorated and the toner charge amount is decreased. ..

[0009]

As described above, in the conventional electrophotographic recording apparatus, when the developer remaining on the photoconductor is collected by the developing device, the paper dust adhered to the photoconductor is also developed. The paper dust reduces the triboelectrification property of the toner and reduces the charge amount. When the charge amount of the toner decreases in this way, white background fogging and image blurring occur, and the image quality deteriorates.

The present invention has been made in consideration of such circumstances, and its purpose is to improve the utilization efficiency of the developer by recovering the developer remaining on the photoreceptor by a developing device. Accordingly, it is an object of the present invention to provide an electrophotographic recording apparatus capable of performing good recording by preventing the chargeability of a developer from being deteriorated by paper dust.

[0011]

SUMMARY OF THE INVENTION The present invention provides a developing device,
The developer (toner) is stored in contact with a storage container such as a hopper and a photoconductor such as a photosensitive drum, and carries the developer stored in the storage container and rotates to contact the photoconductor. An endless developer carrying means such as a developing roller, and an endless developer rotating means such as a peeling roller, which is disposed in contact with the developer carrying means at least partially inside the storage container. Peeling means, an electric field generating means such as a power source for generating a predetermined electric field between the peeling means and the developer carrying means, and abuttingly arranged on the peeling means inside the storage container, It comprises a scraping means such as a cleaning blade for scraping off the substance attached to the peeling means.

[0012]

By taking such a measure, the developer and the paper powder collected by the developer carrying means are sucked by the peeling means under the influence of the electric field generated by the electric field generating means, and are removed from the developer carrying means. It is peeled off. Then, the toner and the paper powder attached to the peeling means are scraped off inside the storage container by the scraping means. Therefore, the paper dust diffuses inside the storage container and does not accumulate on the developer carrying means.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a developing device of the electrophotographic recording apparatus according to this embodiment. The same parts as those in FIG. 2 are designated by the same reference numerals.

In the figure, 70 is a hopper that stores toner (not shown). The developing roller 40 is arranged in the opening of the hopper 70 with a part of the developing roller 40 located inside the hopper 70. Further, a conveyance roller 71 is arranged inside the hopper 70 in parallel with the developing roller 40.
Reference numeral 72 denotes a blade for keeping the amount of toner carried by the developing roller 40 and guided to the outside of the hopper 70 constant.

Reference numeral 73 is a peeling roller. The peeling roller 73 is disposed in contact with the developing roller 40 inside the hopper 70. The peeling roller 73 is grounded. A cleaning blade 74 is fixed to the inner wall of the hopper 70 and contacts the peeling roller 73.

The developing roller 40, the conveying roller 71, and the peeling roller 73 described above are rotationally driven in directions indicated by arrows a, b, and c in the drawing by driving systems (not shown). This electrophotographic recording device
Other than this developing device 7, it has the same structure as the conventional electrophotographic recording device shown in FIG.

Next, the operation of the electrophotographic recording apparatus configured as described above will be described. First, the recording operation of this electrophotographic recording apparatus is the same as that of the conventional electrophotographic recording apparatus shown in FIG.

By the way, in the developing device 7, the developing operation and the toner collecting operation are performed in the same manner as in the conventional case, but in the state where these operations are performed, the following operation is performed. That is, the developing roller 40 is supplied with a developing bias of, for example, −200 V from the power source 41, and the peeling roller 73 is grounded.
There is a potential difference of 200 V between the peeling roller 73 and the peeling roller 73. Therefore, the toner attached to the developing roller 40 having a high potential (toner not used in the development and toner collected from the photosensitive drum 1) is attracted to the peeling roller 73 having a low potential. At this time, the paper dust collected by the developing roller 40 from the photosensitive drum 1 together with the toner is also attracted to the peeling roller 73.

The toner and the paper powder attached to the peeling roller 73 are scraped off from the peeling roller 73 by the cleaning blade 74. The toner and paper dust thus scraped off are moved to the center side of the hopper 70 as indicated by an arrow A in the figure due to the rotation of the conveying roller 71 and the like. At this time, the paper dust diffuses into a larger amount of toner.

As described above, according to this embodiment, the paper dust attached to the developing roller 40 is removed by the peeling roller 73 and the cleaning blade 74. Therefore, the paper dust does not accumulate on the developing roller 40, and the triboelectric charging of the toner on the developing roller 40 is always performed well. As a result, it is possible to record an image without degrading the image quality.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the peeling means is in the form of a roller, but it may be a belt or the like. The rotation direction of the peeling roller may be opposite to that in the above embodiment.

In the above embodiment, the power supply 41 for applying the developing bias to the developing roller 40 by grounding the peeling roller 73 is also used as the potential difference generating means.
A voltage may be directly applied to the peeling roller 73.

In the above embodiment, the scraping means has a blade shape, but it may have another shape such as a brush shape. In addition, various modifications can be made without departing from the scope of the present invention.

[0024]

According to the present invention, the developing device is disposed in contact with a storage container such as a hopper that stores a developer (toner) and a photoconductor such as a photosensitive drum, and is stored in the storage container. An endless developer carrying means, such as a developing roller, for carrying the developer and rotating it to come into contact with the photoconductor, and to the developer carrying means in a state where at least a part of the developer carrying means is located inside the storage container. An endless peeling means such as a rotating peeling roller which is disposed in contact with the rotating means, an electric field generating means such as a power source for generating a predetermined electric field between the peeling means and the developer carrying means, and the storage Since it is configured to include a scraping unit such as a cleaning blade, which is disposed inside the container so as to abut on the peeling unit and scrapes off the substance adhering to the peeling unit, it remains on the photoreceptor. The developer in terms of enhanced efficiency of recovery to the developer in the developing device, the electrophotographic recording apparatus to prevent a reduction in charging property of the developer due to paper dust can perform good recording.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a developing device portion of an electrophotographic recording apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a conventional technique.

[Explanation of symbols]

1 ... Photosensitive drum, 7 ... Developing device, 40 ... Developing roller, 4
1 ... Power source, 70 ... Hopper, 73 ... Peeling roller, 74,
Cleaning blade.

Claims (1)

[Claims] 1. An electrophotographic recording apparatus in which a developing device collects a developer remaining on a photoconductor without being completely transferred onto a recording paper, wherein the developing device includes a storage container storing the developer, and a photoconductor. An endless developer carrying means which is disposed in abutment and carries the developer stored in the storage container and rotates to make contact with the photoconductor; and a state in which at least a part is located inside the storage container. A rotating endless stripping means disposed in contact with the developer carrying means, an electric field generating means for generating a predetermined electric field between the stripping means and the developer carrying means, and inside the storage container. Is placed in contact with the peeling means,
An electrophotographic recording apparatus comprising: a scraping unit for scraping off a substance attached to the peeling unit.