	US 7,469,117 B2
	Image forming apparatus, developing unit, and computer system
Toshiya Takahata, Nagano-ken (Japan); Ken Yoshizuka, Nagano-ken (Japan); and Yoichiro Irie, Nagano-ken (Japan)
Assigned to Seiko Epson Corporation, Tokyo (Japan)
Appl. No. 10/514,790 PCT Filed May 16, 2003, PCT No. PCT/JP03/06152 § 371(c)(1), (2), (4) Date Jul. 29, 2005, PCT Pub. No. WO03/098355, PCT Pub. Date Nov. 27, 2003.
Claims priority of application No. 2002-146889 (JP), filed on May 21, 2002; and application No. 2002-146890 (JP), filed on May 21, 2002.
Prior Publication US 2006/0051128 A1, Mar. 09, 2006
Int. Cl. G03G 15/01 (2006.01); G03G 15/10 (2006.01)

U.S. Cl. 399—227 [399/58]

3 Claims

1. An image forming apparatus comprising:

a rotating member provided with a plurality of attach/detach sections, to and from each of which a developing unit having an element that is capable of performing communication can be attached and detached, where the element has an IC chip and a developing-unit-side antenna; and

an antenna for wirelessly communicating, at a plurality of rotation angles of said rotating member, with the elements of the developing units attached respectively to said attach/detach sections;

wherein, when R is an outermost diameter of a path traced by said developing units and r is an outermost diameter of a path traced by said elements when said rotating member is rotated with said developing units attached to said attach/detach sections, then a relationship R>r is satisfied,

wherein each of said elements is provided on a lateral surface of said developing unit, said lateral surface intersecting with an axial direction of rotation of said rotating member when said developing unit is attached to said attach/detach section,

wherein, when said developing unit is attached to said attach/detach section, said antenna is positioned more outward than said element in the axial direction of rotation of said rotating member,

wherein, when L is a distance from a center of said rotating member to a position of the outermost side of said antenna in a radial direction of rotation of said rotating member, then a relationship R/2>L is satisfied.