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US 5,177,626 AGranted
Image reading apparatus for reading a document at a speed corresponding to the document reading density
AssigneeKabushiki Kaisha Toshiba
InventorsTakefumi Nosaki, Kazuo Sasama
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Abstract
A document reading apparatus including a document reading unit for optically reading an image of a document, a document transfer unit for transferring the reading unit at a speed corresponding to the document reading density, and a pulse motor for driving the document transfer unit. The waveform of an exciting current supplied to the pulse motor is changed in accordance with the document reading density, and the pulse motor is rotated at a speed corresponding to the waveform of the exciting current.
Claims14
An image reading apparatus comprising:
- reading means for reading an image of a document at a predetermined reading density;
- transfer means, for moving at least one of the reading means and the document at a speed corresponding to the reading density, said transfer means having a pulse motor;
- and
- motor driving means for outputting an exciting current having a plurality of current waveforms each corresponding to one step of rotation of said pulse motor, each of said current waveforms being a stepped waveform including a plurality of steps, and said motor driving means including means for changing the number of the steps of each of the current waveforms of the exciting current in accordance with the reading density.
1 more element
An image reading apparatus comprising:
- reading means for reading an image of a document at a predetermined reading density;
- transfer means, for moving at least one of the reading means and the document at a speed corresponding to the reading density, said transfer means having a pulse motor;
- reference excitation signal generating means for generating a reference excitation signal having a plurality of waveforms each corresponding to one step of rotation and each being a stepped waveform having a plurality of steps, said reference excitation signal generating means including means for changing the number of the steps of the stepped waveform of the reference excitation signal in accordance with the reading density;
- excitation signal generating means for converting the reference excitation signal into an excitation signal having a stepped waveform corresponding to the stepped waveform of the reference excitation signal;
- and
- means for driving the pulse motor in accordance with the excitation signal from the excitation signal generating means.
3 more elements
Dependencies are inferred from the claim text.