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:
Jun. 06, 2000
Filed:
Aug. 26, 1997
Masahisa Ochiai, Fukaya, JP;
Masumi Asanae, Kumagaya, JP;
Toshihiko Noshiro, Kumagaya, JP;
Koji Noguchi, Saitama, JP;
Hitachi Metals, Ltd., Tokyo, JP;
Abstract
An image forming method for operating a moving image-bearing member bearing an electrostatic latent image and a plurality of developing units disposed near the image-bearing member and being selectively operable is described. The color image forming method develops the electrostatic latent image by using a magnetic developer brush formed on the surface of a developer support and conveyance means, and includes the steps of: providing a rotating cylinder for supporting and conveying the magnetic developer, the cylinder including a permanent magnet with a plurality of magnetic poles on the cylinder surface; supplying a magnetic developer containing non-magnetic color toner for color image formation; attracting and conveying a layer of magnetic developer having a smaller thickness than the gap between the image-bearing member and the developer support and conveyance cylinder on the cylinder surface; and applying in the developing region an alternate electric field with an AC bias superimposed on a DC bias between the image-bearing member and the magnetic developer for the developing of an electrostatic latent image on the image-bearing member. The method also includes a surface magnetic flux density ranging from 50 to 1200 G, and a value of h, defined as .pi.D.multidot.V.sub.p /(M.multidot.V.sub.m), of 2 or less wherein V.sub.p (mm/s) is the moving speed of the image-bearer, and D (mm), M, and V.sub.m (mm/s) are the outer diameter, the number of magnetic poles, and the peripheral speed of the permanent magnet, respectively.