Abstract: In a multicolor printing apparatus in which a laser beam is scanned by a rotary polygon mirror to form an electrostatic latent image on a photosensitive medium, multicolor printing is effected by forming images of individual plural colors. When plane mirrors of the rotary polygon mirror which are used for scanning to form the head lines of images of different colors differ from each other, the difference in plane inclination between plane mirrors causes color shift or misregistration and image deformation. In order to prevent this disadvantage, the same mirror plane of the rotary polygon mirror is managed to be used for scanning to form the head lines of images of different colors.

Abstract: A printing device according to the present invention can be connected to various computers or the like. A large number of data items for setting various functions are already stored in a storing device of the printing device, and these data items are classified into a multi-step hierarchy to enable the selection of data items of different hierarchies, whereby the functions of the printing device can be set. The printing device is characterized in that, when data of a certain hierarchy is determined, at least one data item of the next hierarchy is arranged to be displayed by a display device, so that the number of key operations is reduced to facilitate data selection.