Foreign material removing device and developing apparatus comprising the same

• US 5,335,051 A
• Filed: 09/08/1992
• Issued: 08/02/1994
• Est. Priority Date: 09/08/1991
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Tani, Tatsuo
• Primary Examiner(s): Pendegrass, Joan H.
• Application Number:
  US07/942,047
• Time in Patent Office: 693 Days
• Field of Search: 355/245, 355/298, 355/251, 355/253, 209/39, 209/40, 209/222, 209/225-228, 118/652
• US Class Current: 399/253
• CPC Class Codes: G03G 15/0887 Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
• CPC Class Codes: G03G 15/0891 for conveying or circulating developer, e.g. augers
• CPC Class Codes: G03G 21/105 Arrangements for conveying toner waste

Abstract

A foreign material removing device for removing foreign materials from a developer for use in electrophotography and a development apparatus including such a foreign material removing device removes foreign materials from the developer employed in the development apparatus by conveying developer to and from a separator, the separator having a rotating disk of magnets for conveying and separating by conveying the developer and allowing the foreign material to fall into a container.

Claims

1. In a development apparatus comprising (a) a development unit provided with (i) a developer holding portion for holding therein a developer comprising a magnetic carrier and a toner, (ii) a developer bearing member for transporting said developer from said developer holding portion into a facing gap portion between the surface of a latent image bearing member and the surface of said developer bearing member, causing said developer to pass through said facing gap portion, and recovering said developer which has passed through said facing gap portion, and (iii) electric charge application means for applying electric charges to said toner contained in said developer which is to be carried by said developer bearing member to said facing gap portion, and (b) a toner holding unit for holding therein said toner to be supplied to said developer holding portion, said developer being transported onto said charge application means, thereby electrically charging said toner in said developer, and said developer being returned to said developer holding portion after said developer is transported to said latent image bearing member and a latent image formed on said latent image bearing member is developed with said toner to a visible toner image, the improvement wherein there are provided:

first developer transport means for transporting said developer to the outside of said development unit;

second developer transport means for transporting said developer into said development unit from the outside thereof;

third developer transport means for receiving said developer from said first developer transport means and transporting said developer to said second developer transport means by use of magnetic force; and

foreign material recovering means for recovering foreign materials which cannot be transported by the magnetic force of said third developer transport means,

a developer inlet for taking in said developer of said first developer transport means being situated, in a circulation path for said developer, at a position between said charge application means and said facing gap portion, or at a position between said facing gap portion and said developer holding portion.

2. The development apparatus of claim 1, further including mixing means for mixing developer during transport by each of said first developer transport means and said second development transport means.

3. A development apparatus for developing a latent image formed on a latent image bearing member with a magnetic developer, comprising:

first developer transport means for transporting said developer to the outside of a development unit;

second developer transport means for transporting said developer into said development unit from the outside thereof;

third developer transport means comprising a developer guide wall, developer suction means for sucking said developer by magnetic force through said developer guide wall, and means for moving said developer suction means, and capable of receiving said developer from said first developer transport means and transporting said developer to said second developer transport means; and

foreign material recovering means for recovering foreign materials contained in said developer, which cannot be transported by said third developer transport means.

4. The development apparatus of claim 3, further including mixing means for mixing developer during transport by each of said first developer transport means and said second developer transport means.

5. A foreign material removing device for removing foreign materials from a developer comprising:

a developer guide member which is hollow, constitutes a substantially U-shaped developer transport path, disposed outside a development unit, and includes an opening in part of a lower guide wall thereof;

magnetic field generating means for generating a magnetic field with the poles thereof being successively rotatable along said developer transport path;

a receiving member disposed below said opening;

developer transport means for transporting said developer in said development unit to one end portion of said developer guide member; and

developer transport means for transporting said developer from the other end portion of said developer guide member to said development unit.

6. The development apparatus of claim 5, further including mixing means for mixing developer during transport by each of said developer transport means.

7. A development apparatus for developing latent images formed on a latent image bearing member with a magnetic developer, comprising:

a developer guide member including an opening at a lower portion thereof, with concave and convex portions being formed at least part of the inner peripheral surface thereof;

magnetic field generating means for generating a magnetic field with the magnetic poles thereof being movable along said concave and convex portions of said developer guide member; and

a receiving member disposed below said opening.

8. The development apparatus of claim 7, further including transport mixing means for transporting said developer to and from said developer guide member and for mixing said developer during transport.

9. A development apparatus for developing latent images formed on a latent image bearing member with a magnetic developer, comprising:

a transport arrangement for transporting developer to and from a separator;

said separator including a pipe through which said magnetic developer travels, said pipe having an opening at a lower end thereof, said separator further including movable magnetic force means located above said pipe for generating a moving magnetic force which transport said magnetic developer through said pipe while foreign material drops through said opening, whereby said pipe and said movable magnetic force means in combination transport said magnetic developer while separating foreign material from said magnetic developer and while said pipe maintains said magnetic developer separate from said movable magnetic means.

10. A development apparatus for developing latent images formed on a latent image bearing member with a magnetic developer, comprising:

a transport arrangement for transporting developer to and from a separator;

said separator including magnetic means for both transporting developer through said separator and for separating foreign material from said developer;

wherein said separator is located outside of a development unit of the development apparatus, and said transport arrangement transports developer from said development unit to said separator.

11. The development apparatus of claim 10, wherein said separator includes an opening into which foreign material enters as said magnetic means transports toner therepast.