Image reading apparatus, image forming device, and method for controlling reading so frequency of pulse signal to stepper motor reduces vibration during quiet scanning mode

摘要

A light source section of the image reading apparatus illuminates a document with light. An image sensor outputs image signals. An operating section accepts input of an enlargement factor and selection of a document scanning mode. An image processing section generates image data, from pixels (lines) in a quantity according to an enlargement factor. A stepper motor moves the document or the light source section. During a quiet mode, a signal generating section inputs to the stepper motor a pulse signal of a fixed frequency within a quiet mode frequency band. The quiet mode frequency band is a frequency band in which vibration of the stepper motor is at or below a predetermined normal vibration level.

主权项

1. An image reading apparatus, comprising:
a light source section for illuminating a document with light; an image sensor for receiving reflected light from the document, and outputting image signals in single-line units in a main scanning direction; an optical system member for directing the reflected light from the document to the image sensor; an operating section for accepting input of an enlargement factor at which to scan the document, and for accepting selection of a scanning mode for the document, including a normal mode and a quiet mode; an image processing section for generating image data of the document from pixels in a quantity according to the enlargement factor set from the operating section, doing so on the basis of the image signal outputted by the image sensor; a stepper motor for prompting movement by either the document or the light source section, or both; and a signal generating section for generating a pulse signal; inputting the generated pulse signal into the stepper motor; prompting the stepper motor to rotate at a speed in accordance with the frequency of the generated pulse signal; and, during scanning in the quiet mode, generating and inputting to the stepper motor a pulse signal of a frequency contained within a predetermined quiet mode frequency band, the quiet mode frequency band being a frequency band in which vibration based on rotation of the stepper motor is at or below a predetermined normal vibration level.