Patent ID: 8449061
Filing Date: 2013-05-28
Classification: B41J,G01P,G03G

Abstract:
1. A speed calculation device for a printing apparatus including inkjet recording heads each having a plurality of image forming elements, the device comprising: a rotary encoder that generates a plurality of pulse signals with different phases in accordance with rotation of an image forming drum of the printing apparatus; a programmable detection component that detects rises and falls of respective pulses of the plurality of pulse signals generated by the rotary encoder; the programmable detection component including a duration calculation component that, each time a rise or fall is detected by the detection component, calculates a total duration of a pre-specified number of durations representing detection intervals of rises or falls detected by the detection component prior to the current rise or fall detected by the detection component; and the programmable detection component including a speed calculation component that calculates a speed relating to rotation of the image forming drum on the basis of the total duration and a rotation angle of the image forming drum that corresponds to one pulse of the pulse signals, to output a clock signal whereby the image forming elements form dots that respectively constitute an image at a predetermined surface synchronously with the clock signal to suppress deformation of the image due to variations in speed relating to rotation of the image forming drum.