| 摘要 |
PROBLEM TO BE SOLVED: To provide an overlap image deviation detecting method capable of easily detecting the positional deviation due to an inclination in a main scanning direction, ad a multiimage forming device concerning the aforesaid method. SOLUTION: It is assumed that the positional deviation in the main scanning direction and the positional deviation in a sub scanning direction of the printing start end are already mechanically corrected, or already corrected under an output timing control, but a skew correction is not finished yet. A test pattern constituted of plural line groups which are parallel in the main scanning direction is previously prepared in a memory, and overlap images as the test pattern by a reference color (e.g. magenta M) and another color (e.g. yellow Y) are printed. When the positional deviation due to the inclination in the main scanning direction is generated, Moir fringes are generated. In the case of three-line positional deviation, both end parts and an intersection part k3 are viewed green, non-intersection part k4 other than the aforesaid parts is viewed as mixed colors, red and yellow. Provided that (n) denotes the number of intersection fringes (k1, or k3) of Moir fringes and (d) denotes the number of pixels which are deviated in terms of position, d=n+1 is established. Besides, provided that (m) denotes the number of non-intersection fringes (k2, or k4), d=m is established. |
