Image reading apparatus and method
AssigneeCanon Kabushiki Kaisha
InventorYoshito Haba
Life of this patent
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Abstract
An image reading apparatus prevents degradation of image quality and a delay in the image reading time which are caused by interruption of reading of image data. A speed at which a host computer reads image data from an image reading apparatus and temporarily stores it therein is examined. If the resulting speed is lower than a reference value which has been set so that an operation to avoid an overflow of a buffer RAM in the image reading apparatus may not be caused, the sub-scanning speed of the image reading apparatus is set lower, and the image is read at the lower speed.
Claims13
An image reading system comprising:
- (A) an image reading apparatus comprising:
- (i) an image reading unit having a photoelectric conversion component for reading light from an image and converting the read image to an image signal;
- (ii) a driving motor for moving said image reading unit and the image relative to each other;
- (iii) a motor control unit for controlling said driving motor;
- (iv) a conversion circuit for performing analog-to-digital conversion on the image signal into image data;
- and
- (v) an image memory for storing the image data;
- and
- (B) an information processing apparatus comprising:
- (i) a temporary storage memory for reading and temporarily storing the image data stored in said image memory;
- (ii) a first timer for measuring the speed of the data stored in said temporary storage memory;
- and
- (iii) a control signal generating unit for outputting a motor control signal to said motor control unit based on the measurement of said first timer,
- wherein said motor control unit controls said driving motor according to the motor control signal output by said control signal generating unit,
- wherein, based on the measurement of said first timer, said control signal generating unit outputs the motor control signal which controls said driving motor so as to satisfy the relationship V1≦V2, where V1 represents a data speed at which the image is read to generate the image data, and V2 represents a data speed at which the image data is stored in said temporary storage memory, and
- wherein said motor control unit controls said driving motor according to the motor control signal.
A controlling method for controlling an image reading system, comprising the steps of:
- reading image data at a predetermined read speed to generate image data;
- storing the image data in storage means;
- reading out the image data stored in the storage means via an interface;
- temporarily storing the image data, which is read out in the reading out step, in a temporary storage memory;
- and
- detecting a speed at which the temporary storage memory temporarily stores the image data,
- wherein the read speed in the reading step is controlled according to the speed detected in the detecting step,
- said controlling method further comprising the step of controlling the read speed of the image data to be lower if the speed detected in the detecting step is lower than a predetermined value.
Dependencies are inferred from the claim text.