Image reading device, image reading method, and image forming apparatus including the image reading device

An image reading method for an image reading device,

• the device comprising a first carriage and a second carriage, each carriage containing optical elements for reading an image of a document;
• a carriage driving unit comprising a pulse motor to move the first and second carriages;
• a home position sensor to detect a home position of the first carriage;
• a reference whiteboard to generate shading data and adjust a reference level to be read by the optical elements;
• a control unit to control the first and second carriages, the carriage driving unit, the home position sensor, and the reference whiteboard to read the image of the document placed on a contact glass through the optical elements;
• and
• a counter to count a pulse of a pulse signal driving the pulse motor,
• the method comprising:
• switching directions of movement of the first carriage based on a result output from the home position sensor when the image reading device is returned to an active mode from an energy-saving mode;
• and
• detecting a distance of movement of the first carriage based on the pulse counted by the counter.

An image reading device, comprising:

• a first carriage comprising optical elements for reading an image of a document;
• a second carriage comprising optical elements for reading the image of the document;
• carriage driving means for moving the first and second carriages;
• home position sensing means for detecting a home position of the first carriage;
• a reference whiteboard for generating shading data and adjusting a reference level to be read by the optical elements;
• control means for controlling the first and second carriages, the carriage driving means, the home position sensing means, and the reference whiteboard to read the image of the document placed on a contact glass through the optical elements;
• and
• counting means for counting a pulse of a pulse signal,
• wherein the control means switches directions of movement of the first carriage based on a result output from the home position sensing means when the image reading device is returned to an active mode from an energy-saving mode, and detects a distance of movement of the first carriage based on the pulse counted by the counting means.