JP2008292798A - Development device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development device which can reduce printing smudges due to paper powder and aggregated toner. <P>SOLUTION: A flat and smooth plate 3 is disposed at the area facing the magnet roll 6 in the upper opening of the developing unit B. This flat and smooth plate 3 is vibrated to shake off the paper powder and the aggregated toner before they grow large in order to reduce printing smudges. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides a charger for charging a photosensitive member around the photosensitive member, an optical device for exposing the charged photosensitive member to form an electrostatic latent image on the photosensitive member, and a rotatable device to which a predetermined voltage is applied. A developing device for developing an electrostatic latent image formed on the photosensitive member in a developing unit that has a developing roller, conveys the developer onto the developing roller, and the developer on the developing roller contacts the photosensitive member, The present invention relates to an electrophotographic apparatus having a transfer device for copying a developed image to a printing paper, and more particularly to a developing apparatus therefor.

  In the conventional technology, a developing device is applied by applying a charge of the same polarity as that of the developing roll to a flat and smooth member facing the developing roll in the vicinity of the developing device opening upstream of the developing portion in the developer transport direction. Prevents scattering of paper dust and toner outside the opening.

  An example of paper dust and toner accumulation in a conventional developing device is shown in FIG. In this example, a two-component developer 5 composed of toner and a carrier that is magnetic powder is used. In the toner recycling apparatus, the paper dust mixed in the recycled toner is returned to the toner supply device (not shown) and mixed into the developing device 2 from the toner supply device. These mixed paper dusts are mixed in the developer 5 in the process in which the developer 5 is sufficiently mixed and stirred by the stirring member 7 in order to impart a predetermined charge amount to the toner by frictional charging with the carrier. It is supported on the developing device 2 and is supported on a magnet roll 6 which is a developing roll having a predetermined magnetic pattern inside. The transport amount is regulated by the doctor plate 4 and then scattered on the magnet roll 6. Stays near the part.

  The staying paper powder gradually accumulates to become a paper powder and toner lump 10. When the paper dust and toner lump 10 are larger than a certain size, they fall to the surface of the developer 5 on the magnet roll 6 by the vibration of the developing device. The dropped lump 10 is transported to the developing section B without being agitated in the developer 5 and adheres onto the photoreceptor 1 at the developing section B. This lump 10 adhering to the photoreceptor 1 is transferred to printing paper and becomes print stains in a transfer device (not shown). Before this printing stain occurs, maintenance such as periodically cleaning the C portion of the cover 11 is required. In particular, when printing paper such as recycled paper, which is likely to generate paper dust, is used, cleaning and maintenance are frequently performed, causing problems that hinder the user's work.

  For example, the following patent documents can be cited regarding this type of technology.

JP-A-10-123842 Japanese Patent Laid-Open No. 03-059687

  When the size of the paper dust and toner lump 10 exceeds a certain level, the lump 10 falls to the surface of the developer 5 on the magnet roll 6 due to the vibration of the apparatus. The dropped lump 10 is transported to the developing section B without being agitated in the developer 5 and adheres onto the photoreceptor 1 at the developing section B. This lump 10 adhering to the photoreceptor 1 is transferred to printing paper and becomes print stains in a transfer device (not shown).

  An object of the present invention is to provide a developing device that eliminates the drawbacks of the prior art and does not cause printing stains due to paper dust or toner lump.

  In order to achieve the above object, the present invention is characterized in that a substantially flat and smooth member is disposed in the vicinity of the upper opening of the developing roll facing the photosensitive member, and a vibrating member for vibrating the smooth member is provided. To do.

  The present invention has the above-described configuration, and by causing the substantially flat and smooth member to vibrate, the growth of a lump of paper powder and toner in the vicinity of the developing roll is suppressed, resulting from the lump. Print stains can be reduced.

  An embodiment of the present invention will be described below with reference to FIG.

  A developing device 2 that develops an electrostatic latent image on the photosensitive member 1 while facing the photosensitive member 1 that is charged by a charger (not shown) while rotating and is exposed by an optical unit (not shown) to form an electrostatic latent image. Is arranged.

  In the developing device 2, the two-component developer 5 composed of toner and carrier is mixed and stirred by the stirring member 7, and is triboelectrically charged and has a charge. The developer 5 is rotatably supported by a developing device and is conveyed onto a magnet roll 6 having a predetermined magnetic pattern therein, thereby forming a magnetic brush on the magnet roll 6. The developer 5 transported onto the magnet roll 6 is regulated to a predetermined developer thickness by the doctor plate 4 and then transported to the developing section B and developed in accordance with the electrostatic latent image formed on the photoreceptor 1. Then, it returns to the inside of the developing device 2 again and is mixed and stirred. A flat and smooth conductive member 3 is provided at a portion facing the magnet roll 6 at the upper opening in the developing portion B (see FIG. 2) of the developing device 2, and the same conductive member 3 as the magnet roll 6 is provided on the conductive member 3. Apply voltage. Furthermore, a vibrating member 11 is attached to the upper surface of the conductive member 3, that is, the surface opposite to the magnet roll 6.

  Here, the carrier in the developer 5 is attracted to the magnet roll 6 by a magnetic force, and the toner has a charge opposite to that of the carrier due to frictional charging with the carrier, and is electrostatically coupled to the carrier. Paper dust generated from the printing paper is mixed into the developing device 2 in the same manner as in the case of the conventional developing device. A part of the mixed paper dust floats on the surface of the developer 5 in the developing device 2 as in the case of the prior art. The floated paper dust is scattered by the upper part of the magnet roll 6 after being regulated by the doctor plate 4, but is flat and smooth on the part facing the magnet roll 6 in the upper opening of the developing part, such as an aluminum plate. Since the conductive member 3 is provided and the conductive member 3 is vibrated by the vibration member 11, the paper powder and toner lump do not grow greatly and fall off, and therefore a large paper dust and toner lump causing print stains. Is no longer generated. Thereby, printing stains due to paper dust and toner can be reduced.

1 is a schematic sectional view of a developing device according to an embodiment of the present invention. It is a schematic sectional drawing of the image development apparatus which shows an example of the malfunction by a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Photoconductor, 2 Developing device, 3 Conductive member, 4 Doctor blade, 5 Developer, 6 Magnet roll, 7 Stirring member, 8 Scraper, 10 Paper dust and toner lump, 11 Vibration member, A Developing device opening, B Development section, C Paper powder retention section.

Claims (1)

  A developing device comprising: a substantially flat and smooth member disposed in the vicinity of an upper opening of a developing roll facing a photosensitive member; and a vibrating member for vibrating the smooth member.

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