Image reading device and image forming apparatus

An image reading device comprising:

• an image sensor to read an image on an object;
• and
• a light source to emit light to the object;
• a carriage:
• movable in a forward direction and a return direction opposite to the forward direction;
• and
• performs a first reciprocal scanning operation starting from a first position,
• the carriage mounting at least one of:
• the image sensor;
• or
• the light source;
• a position sensor to:
• detect the carriage, in the forward direction, at:
• the first position;
• and
• a second position different from the first position;
• and
• switch a ON/OFF state between ON and OFF in accordance with a detection of the carriage at the second position;
• a motor to move the carriage to perform the first reciprocal scanning operation;
• and
• circuitry configured to:
• generate a clock signal to generate a drive signal;
• output, to the motor, the drive signal in accordance with the clock signal to drive the motor to move the carriage;
• count a number of pulses of the clock signal;
• determine whether the carriage has an abnormality based on:
• the number of pulses of the clock signal;
• and
• the ON/OFF state of the position sensor;
• and
• cause the motor to, when the circuitry determines that the carriage has the abnormality:
• move the carriage back to the first position in the return direction;
• and
• move the carriage in the forward direction to change the ON/OFF state of the position sensor to perform a second reciprocal scanning operation,
• wherein the circuitry is further configured to:
• move the carriage a first moving distance in the first reciprocal scanning operation;
• and
• move the carriage a second moving distance, equal to or greater than the first moving distance, in the second reciprocal scanning operation.