Velocity correction device and velocity correction method in image forming apparatus

A velocity correction method in an image forming apparatus including a rotor, a motor for driving the rotor, a motor control unit for controlling an operation of the motor, and a velocity command memory for storing velocity command data and supplying the motor control unit with a command signal based on the velocity command data, wherein the image forming apparatus does not include a velocity measuring unit for correcting a rotational velocity of the rotor, the velocity correction method comprising the steps of:

• preparing a velocity correction device including a velocity measuring unit for measuring a rotational velocity or a peripheral velocity of the rotor of the image forming apparatus, an arithmetic unit, and an interface unit for supplying the velocity command data to the velocity command memory of the image forming apparatus;
• attaching the velocity correction device to the image forming apparatus in a manufacturing process of the image forming apparatus or in a replacement process of a unit in which the rotor is mounted so that the rotational velocity or peripheral velocity of the rotor is measurable by the velocity measuring unit of the velocity correction device;
• connecting the interface unit of the velocity correction device to the velocity command memory of the image forming apparatus;
• rotating the motor of the image forming apparatus at a reference rotational velocity which is a fixed velocity, making the velocity measuring unit measure the rotational velocity or the peripheral velocity of the rotor when the motor is rotating at the reference rotational velocity, and supplying the measured velocity to the arithmetic unit;
• making the arithmetic unit compare the measured velocity with a no-velocity-fluctuation velocity of the rotor calculated by the reference rotational velocity of the motor, extract a velocity fluctuation component of the rotor, and generate the velocity command data to cancel the extracted velocity fluctuation component;
• transmitting the generated velocity command data to the velocity command memory of the image forming apparatus through the interface unit, and storing the velocity command data in the velocity command memory;
• removing the velocity correction unit from the image forming apparatus after storing the velocity command data;
• and
• when the image forming apparatus which is delivered without the velocity correction device is operated by a user, reading the stored velocity command data from the velocity command memory, and supplying the velocity command data to the motor control unit so that the motor can perform the operation.