Image reading device for scanning a document in first and second modes
AssigneeRicoh Company, Ltd.
InventorKazushige Taguchi
Life of this patent
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Abstract
An image reading device has two different modes for controlling the switchover of a motor drive pattern. Either one of the two modes is selected in accordance with various drive conditions including a drive speed. In one mode, in response to every drive pattern switching pulse, pattern data are output by software processing while a position signal is referenced. In the other mode, a macro transfer function is used to output the pattern data by DMA (Direct Memory Access) while the position signal is referenced at every repetition cycle of the drive patterns. The device is capable of reading an image at high speed by switching the drive pattern rapidly, thereby obviating irregularity in a reference position for reading an image.
Claims14
An image reading device comprising:
- a movable scanning mechanism including image reading means;
- a pulse motor for driving said movable scanning mechanism;
- position sensing means for sensing a position of said movable scanning mechanism;
- drive control means for controlling drive of said pulse motor in response to an output signal of said position sensing means;
- first monitoring means for monitoring the output signal of said position sensing means at one pulse period for switching a drive phase of said pulse motor;
- second monitoring means for monitoring the output signal of said position sensing means at a plurality of pulse periods for switching the drive phase of said pulse motor;
- and
- selection control means for selecting either said first monitoring means or said second monitoring means in accordance with an instantaneous drive condition, and controlling the drive of said pulse motor by using the selected monitoring means.
An image reading device comprising:
- a movable scanning mechanism including a scanner;
- a pulse motor driving said movable scanning mechanism;
- a position sensor sensing a position of said movable scanning mechanism;
- a drive controller controlling drive of said pulse motor in response to an output signal of said position sensor;
- a first monitoring device monitoring the output signal of said position sensor at one pulse period for switching a drive phase of said pulse motor;
- a second monitoring device monitoring the output signal of said position sensor at a plurality of pulse periods for switching the drive phase of said pulse motor;
- and
- a selection controller selecting either said first monitoring device or said second monitoring device in accordance with an instantaneous drive condition, and controlling the drive of said pulse motor by using the selected monitoring device.
Dependencies are inferred from the claim text.