Patent ID: 7289744
Filing Date: 2007-10-30
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image bearing member which bears a toner image; transfer means which is in contact with said image bearing member to form a transfer nip portion, which sandwiches and conveys recording material with said image bearing member in said transfer nip portion, and which transfers said toner image to said recording material; fixing means in which said recording material is sandwiched in a fixing nip portion where a first fixing member and a second fixing member are in contact with each other, the fixing means which fixes said toner image to said recording material; and an electrode member which is provided between said transfer means and said fixing means, wherein said recording material is sandwiched and conveyed by said fixing means while sandwiched and conveyed by said transfer means, a length d (mm) of a shortest straight line connecting a center of said transfer nip portion and a center of said fixing nip portion in a direction in which said recording material is conveyed satisfies 0 (mm)<d<=80 (mm), and wherein assuming that an angle formed by said shortest straight line and a tangent being in contact with said transfer means in the center of said transfer nip portion is φ (rad), a distance between the center of said transfer nip portion and a position nearest to said recording material of said electrode member is j (mm) in the direction parallel to said tangent being in contact with said transfer means, a maximum length of said recording material is P (mm) in the direction in which the recording material is conveyed, a speed at which said recording material is conveyed by said transfer means is V (mm/sec), and a maximum speed difference generated between said speed V (mm/sec) and a speed at which said recording material is conveyed by said fixing means is ΔV (mm/sec), said angle φ satisfies 0<j×ABS(φ−ACOS(d/(d/COS φ+(P−d/COS φ)×ΔV/V)))<=1 (mm), where ABS is a function which determines an absolute value and ACOS is an inverse function of COS.