JPH07199647A - Developing device - Google Patents

Abstract

PURPOSE:To prevent an adverse effect due to a reverse polarity charge even using one component toner and to form an excellent image by making the rotary direction of the first toner transporting means and the rotary direction of the second toner transporting means in the forward direction. CONSTITUTION:The second roller shape toner transporting means 3 is held in contact with the first roller shape toner transporting means 2. Then, the toner quantity (thickness of toner layer) is regulated by the developing blade 1, and the toner is triboelectrified by the developing blade 1 and the first toner transporting means 2. The toriboelectrified toner is shift-stuck to the second toner transporting means 3 from the first toner transporting means 2 by the force of the electric field. At this time, the first toner transporting means 2 and the second toner transporting means 3 are rotated in the forward direction for supplying the toner. Thus, the toner is shift-stuck only by the force of the electric field, therefore the the toner other than normally triboelectrified toner is hardly supplied to the second toner transporting means 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device applicable to a recording device such as a facsimile, a copying machine, a printer and the like.

[0002]

2. Description of the Related Art Generally, in this type of recording apparatus, if a one-component toner can be used as the toner, the developing apparatus can be downsized, and maintenance is basically unnecessary. Are known. On the other hand, there are problems that the reliability is low, it is difficult to uniformly charge the toner, and there is a reversely charged toner that has a polarity opposite to the desired polarity. If the reversely charged toner is present, the reversely charged toner adheres to the background portion and causes the background stain.

Although it is necessary to form a toner layer on the developer carrying member with uniformly charged toner, the amount of toner on the developer carrying member cannot be increased so much for uniform charging. Further, if the linear velocity ratio between the developer carrying member and the image carrying member is increased, the scavenging force becomes too large, and problems such as frictional charging between the image carrying member and the toner easily occur.

Whether the toner is triboelectrically charged by the toner amount regulating member and the first toner carrying means or the charging is performed by the charge injection, the amount of toner which can be uniformly charged (per unit area on the first toner carrying means) There is a limit to the amount of toner. Beyond the limit, the proportion of toner charged to the opposite polarity increases. Therefore, in order to uniformly charge the toner, the amount of toner on the first toner conveying unit cannot always be made equal to the amount of toner required on the image carrier.

[0005]

Therefore, under the present circumstances, it is necessary to design by balancing "the amount of toner on the developer carrier" and "the linear velocity ratio between the developer carrier and the image carrier". No, it did not always result in good images.

It is an object of the present invention to provide a developing device which is capable of forming a good image without using the one-component toner while eliminating the adverse effects of the oppositely charged toner.

[0007]

In order to achieve the above-mentioned object, the developing device of the present invention is a developing device using a one-component toner, wherein the first toner carrying means and the toner on the first toner carrying means are provided. The toner amount regulating means for regulating the amount and the first toner conveying means rotate in the forward direction, and the regulated toner is transferred and adhered at the contact point with the first toner conveying means to allow the toner to remain on the image carrier. And a second toner conveying unit for developing the electrostatic latent image.

[0008]

According to the above means, the toner amount is regulated on the first toner conveying means by the toner amount regulating means, and then the second toner is regulated.
In order to transfer and attach the toner to the toner conveying means and to develop the toner on the image carrier by the second toner conveying means,
The background charge does not cause background stain. And the first
Since the rotation direction of the toner transporting means and the rotation direction of the second toner transporting means are set to the forward direction, the toner that is transferred and attached only by the force of the electric field and is not normally charged is not supplied to the second toner transporting means. Few. Further, the toner is not squeezed in the nip portion, and the stress that the toner receives is smaller than that in the counter. Further, since toner is not squeezed in the nip portion, it is difficult for toner to accumulate near the nip portion. Therefore, toner spillage and toner scattering are less likely to occur. Further, the rotation load can be reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a developing device according to the present invention. In a developing device 10 containing a one-component toner, a developing blade 1 as a toner amount regulating means and a roller-shaped first The toner carrying means 2 is provided, and the first toner carrying means 2 is in contact with the roller-shaped second toner carrying means 3. Then, the toner amount (thickness of the toner layer) is regulated by the developing blade 1, and the toner is triboelectrically charged by the developing blade 1 and the first toner conveying means 2. The frictionally charged toner is transferred and adhered from the first toner carrying means 2 to the second toner carrying means 3 by the force of the electric field. Further, the second toner conveying means 3 causes toner to adhere to the photosensitive drum 4 which is an image carrier to develop the electrostatic latent image.

Around the photosensitive drum 4, there are arranged known electrophotographic image forming components such as a charger 5, a laser writing system 6, a transfer unit 7, a cleaning unit 8 and a charge eliminating system 9. ing.

When transferring the triboelectrically charged toner from the first toner conveying means 2 to the second toner conveying means 3,
The first toner conveying means 2 and the second toner conveying means 3 are rotated in the forward direction to supply the toner. Therefore, (1) since the toner is transferred and adhered only by the force of the electric field, the toner that is not normally charged is rarely supplied to the second toner conveying unit 3.

(2) The toner is not squeezed in the nip portion, and the stress that the toner receives is smaller than that of the counter.

(3) Since toner is not squeezed in the nip portion, it is difficult for toner to accumulate in the vicinity of the nip portion.
Therefore, toner spillage and toner scattering are less likely to occur.

(4) Rotational load can be reduced.

The above situation can be seen from the model diagrams showing the movement of the toner T in FIGS. 2 and 3.

[0017]

As described above, according to the present invention,
To regulate the amount of toner by the toner amount regulating unit on the first toner conveying unit, transfer the toner to the second toner conveying unit, and develop the toner on the image carrier by the second toner conveying unit. Also, there is an effect of preventing the background stain due to the oppositely charged toner.

Further, since the rotation direction of the first toner transporting means and the rotation direction of the second toner transporting means are set to the forward direction, the toner that is transferred and attached only by the force of the electric field and is not normally charged is transported to the second toner transporting means. It is rarely supplied to the means. Further, the toner is not squeezed in the nip portion, and the stress that the toner receives is smaller than that in the counter. Further, since toner is not squeezed in the nip portion, it is difficult for toner to accumulate near the nip portion. Therefore, toner spillage and toner scattering are less likely to occur. further,
There is also an effect that the rotational load can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a developing device according to the present invention.

FIG. 2 is a model diagram showing movement of toner.

FIG. 3 is a model diagram showing the movement of toner.

[Explanation of symbols]

1 ... Developing blade (toner amount regulating means), 2 ... First toner conveying means, 3 ... Second toner conveying means, 4 ... Photosensitive drum (image carrier).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Iwamatsu Matsumae 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh Co., Ltd. (72) Yoshiro Tanaka 1-3-3 Nakamagome, Ota-ku, Tokyo Stocks Inside Ricoh Company (72) Inventor Hiroshi Hosokawa 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh (72) Inventor Manjiro Uno 1-3-6 Nakamagome, Tokyo Stockholder Ricoh Company (72) Inventor Hiroshi Saito 1-3-6 Nakamagome, Ota-ku, Tokyo, within Ricoh Company (72) Inventor Eiji Takenaka 1-3-6 Nakamagome, Ota-ku, Tokyo In-house, Ricoh (72) Invention Tetsuo Yamanaka 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Eisaku Murakami 1-3-3 Nakamagome, Ota-ku, Tokyo Stock company In Ricoh (72) Inventor Satoru Komatsubara 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (1)

[Claims] 1. A developing device using a one-component toner, a first toner conveying means, a toner amount regulating means for regulating a toner amount on the first toner conveying means, and the first toner conveying means.
And a second toner conveying means for developing the electrostatic latent image on the image carrier by transferring and adhering the regulated toner to the toner conveying means at the contact point with the first toner conveying means in the forward direction. A developing device characterized in that