Patent ID: 7830403

Claim:
An image-forming device comprising: a conveying unit configured to convey a target in a conveying direction, the target having a target light reflectance; a pattern data generating unit configured to generate pattern data indicating a pattern in which a plurality of marks is arranged in the conveying direction, the plurality of marks including a first mark having a first color and a first light reflectance and a plurality of second marks having a plurality of second colors and a plurality of second light reflectance, the plurality of second colors being equal to or different from one another, the plurality of second light reflectance being equal to or different from one another, a first difference between the target light reflectance and the first light reflectance being greater than a second difference between the target light reflectance and any of the plurality of second light reflectance, a difference between the first light reflectance and any of the second light reflectance being larger than a difference between any two of the second light reflectance, at least one of first distances between the first mark and the marks adjacent to the first mark being greater than a minimum distance between the adjacent second marks; an image-forming unit configured to form the plurality of marks in the conveying direction at positions on the target based on the pattern data; and a detecting unit configured to detect the positions at which the plurality of marks is formed on the target, based on changes of light reflected from the target and the plurality of marks in the conveying direction.