| 摘要 |
PROBLEM TO BE SOLVED: To prevent faulty transfer by preventing the surface charge density of transfer material from getting uneven due to charge supplied from a transfer electrifying means at a transfer part even when speed variation is caused by the fluctuation of the thickness in the peripheral direction of a recording material carrying belt. SOLUTION: In a transfer electrifier, the transfer current ITr of a power source is constant-current controlled, and the variationΔVL of carrying belt speed (recording material carrying speed) V is changed as shown byΔVL=ΔhL.ω(ΔhL: the fluctuation amount of the thickness andω: the angular velocity of a driving roll), and the surface charge densityΔσof the recording material is changed as shown byΔσ=ITr/(V+ΔVL).G-ITr/V.G (G: the thrust length of the electrifier), and the faulty transfer due to too much or too little surface charge density is caused. Then, the thickness of the carrying belt is measured all over the periphery so as to obtain the profile of the thickness distribution all over the periphery. At the time of forming an image, the transfer current ITr is controlled by a control means corresponding toΔVL (according to the profile of the thickness distribution) so as to restrain the change width ofΔσto the minimum.
|
