| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which does not cause color shift even when using cardboard by regulating space between an intermediate transfer belt and a secondary transfer roller in accordance with the thickness of a recording medium. <P>SOLUTION: The rotation in a direction shown by an arrow (a) of a drive shaft 60 by a motor 58 makes a shaft 18a rotate in a direction shown by an arrow (b) through gears 57 and 56. The recording medium P held in a transfer nip part N between the intermediate transfer belt 17 and the secondary transfer roller 18 regulated by pitch rings 51a and 51b is conveyed in an upward direction from the downside of a paper surface by rotation in the direction shown by the arrow (b) of the secondary transfer roller 18. When preventing the color shift caused when using the cardboard, the interval of the transfer nip part N is changed. By rotating the pitch rings 51a and 51b whose outer shape is elliptical through the drive shaft 60 and gears 55 and 54, and setting the rotational angle positions of the pitch rings 51a and 51b detected by a photosensor 61 to the rotational angle positions fit for the thickness of the recording medium, the transfer nip part N fit for the thickness of the recording medium is formed. <P>COPYRIGHT: (C)2009,JPO&INPIT |
