| 摘要 |
PROBLEM TO BE SOLVED: To quickly detect that an external object comes into contact with a body to be carried. SOLUTION: An image forming apparatus forms an image on a sheet by carrying a carriage having a recording head installed therein, in the main scanning direction, and is equipped with a linear encoder. The linear encoder includes: an encoder fence 551 long in the main scanning direction, set perpendicular to a sheet carrying plane in the main scanning direction; and an encoder sensor having a light emitting element and a light receiving element sandwiching the encoder fence. The encoder sensor is fixed to the carriage. On the other hand, a slit 551a provided to the encoder fence is tilted at a predetermined angle to a reference line L perpendicular to the main scanning direction, on the side surface of the encoder fence. Hence, when the carriage is displaced in an upper direction, and a position of the encoder sensor to the encoder fence is changed, the pulse width of an encoder signal is changed. The image forming apparatus detects a contact of the carriage and the sheet, based on the change in the pulse width. COPYRIGHT: (C)2011,JPO&INPIT
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