Image reading apparatus, multifunction printer, and image reading method

An image reading method in an image reading apparatus which reads an original image by using a photoelectric transducer, comprising:

• a first generation step of generating, from a reference signal, a first driving signal to which SSCG spread modulation is applied;
• a second generation step of generating, from the reference signal, a second driving signal to which no SSCG spread modulation is applied;
• a selection step of selecting one of the first driving signal and the second driving signal;
• a timing signal generation step of generating a timing signal for reading the original image, based on the driving signal selected in the selection step;
• a latch step of latching an image signal obtained by the photoelectric transducer, using the timing signal generated in the generation step;
• and
• a transfer step of transferring the image signal latched in the latch step for subsequent image processing,
• wherein in the selection step, in reading of a one-line original image, the second driving signal is selected till completion of a latch operation in the latch step, and after the latch operation, the first driving signal is selected for an image signal transfer operation in the transfer step.

An image reading apparatus which reads an original image by using a photoelectric transducer, comprising:

• a driving signal generation unit configured to generate, from a reference signal, a first driving signal whose frequency is spread-modulated and a second driving signal whose frequency is not spread-modulated;
• a latch unit configured to latch an image signal obtained by the photoelectric transducer, using the second driving signal;
• and
• a transfer unit configured to transfer the image signal latched by said latch unit, using the first driving signal, for subsequent image processing.

An image reading method in an image reading apparatus which reads an original image by using a photoelectric transducer, comprising:

• a first generation step of generating, from a reference signal, a first driving signal whose frequency is spread-modulated;
• a second generation step of generating, from the reference signal, a second driving signal whose frequency is not spread-modulated;
• a latch step of latching an image signal obtained by the photoelectric transducer, using the second driving signal generated in the second generation step;
• and
• a transfer step of transferring the image signal latched in the latch step, using the first driving signal generated in the first generation step, for subsequent image processing.