Patent ID: 8636339

Claim:
An image forming apparatus comprising: a print head to form an image on a recording medium; a movable carriage including the print head and configured to scan reciprocally in a main scanning direction; a linear encoder scale bearing scale marks therein on a surface thereof, extending in a direction of movement of the carriage to detect the position of the carriage; an encoder sensor disposed on a side wall of the carriage and having a groove therein with an open concave shape in cross-section, the encoder sensor reading the scale marks on the linear encoder scale as the linear encoder scale passes through the groove; and a through-hole forming member disposed on the side wall of the carriage configured to cover the encoder sensor, and forming a through-hole extending in the carriage moving direction through which the linear encoder scale is passed, wherein the through-hole forming member is detachably attachable with respect to the carriage.