Patent ID: 7086730

Claim:
An ink-jet printer comprising: a paper feed tray; a paper feed mechanism for conveying a paper sheet in a predetermined paper feeding direction; a carriage facing a predetermined position in the paper feed mechanism and being reciprocally movable in a main scanning direction perpendicular to the paper feeding direction; a carriage driving mechanism for moving the carriage reciprocally in the main scanning direction; an ink-jet head held on the carriage; and a controller for controlling the paper feed mechanism, the carriage driving mechanism and the ink-jet head for forming an image on a surface of the paper sheet using image data; wherein the paper feed mechanism further comprises a delivery roller and a plurality of star rollers facing the delivery roller and being rotated by following the rotation of the delivery roller when the paper sheet intervenes between them, the delivery roller and the plurality of star rollers being provided at a downstream position from an image forming portion facing the ink-jet head in the paper feeding direction; each star roller is constituted by a combination of two star roller units having the same shape; and each star roller unit further comprises: a star wheel made of a metal plate by press working, in which a plurality of contacting portions are provided in a radial pattern at a predetermined angular pitch; a bearing portion integrally formed with the star wheel by an outsert molding; and a convex and concave structure formed on at least an end face of the bearing portion in which a plurality of convex portions have the same pitch and phase as those of the contacting portions of the star wheel, and in which a plurality of concave portions have the same pitch as that of the contacting portions of the star wheel and a phase discrepant by half with respect to the phase of the convex portions so that the convex portions of one star roller unit are engageable with the concave portions of the other star roller unit.