The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 10, 1994
Filed:
Oct. 08, 1991
Tamotsu Shimizu, Settsu, JP;
Hiroshi Murasaki, Ibaragi, JP;
Masahiko Matsuura, Amagasaki, JP;
Susumu Mikawa, Itami, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
In an image forming apparatus accommodating a developing device, a developing roller 1 includes a magnet member 3 non-rotatably fixed and a sleeve 2 rotatably moved around the outer surface of the magnet member 3, powdery developers D held on the outer periphery of the sleeve 2 are brought into contact with a photosensitive member 10 to visualize an electrostatic latent image, and the magnet member 3 is provided with a magnetic pole portion N.sub.0 having first and second magnetic poles N.sub.1 and N.sub.2. The first and second magnetic poles N.sub.1 and N.sub.2 have the same polarities and are adjacent to each other and confront the photosensitive member 10. The powdery developers D include three developer parts, an upper developer D.sub.1, a middle developer D.sub.12 and a lower developer D.sub.2, which are successively retained on the outer surface of the sleeve 2 by the first and second magnetic poles N.sub.1 and N.sub.2. The upper developer D.sub.1 retained by the first magnetic pole N.sub.1 and the middle developer D.sub.12 retained by the middle portion between the first and second magnetic poles N.sub.1 and N.sub.2 are brought into contact with the photosensitive member, while the lower developer D.sub.2 retained by the second magnetic pole N.sub.2 is held out of contact with the photosensitive member.