Data carrier apparatus, communication system, and replaceable unit

A replaceable unit that is attachable to an image forming apparatus, comprising:

• a process member to be used for image formation,
• a data carrier apparatus capable of communicating with a data carrier driving apparatus provided in the image forming apparatus, when attached to the image forming apparatus,
• wherein the data carrier apparatus comprises:
• a first determination unit configured to determine a duty ratio of each pulse of a pulse signal received from the data carrier driving apparatus;
• a second determination unit configured to determine a frequency of each pulse of the received pulse signal;
• a calibration unit configured to perform calibration of a reference value to be used for determination performed by the second determination unit, during a calibration period;
• and
• a demodulation unit configured to demodulate data conveyed by the received pulse signal, the demodulation unit being configured to perform first demodulation based on a determination result of the first determination unit during the calibration period, and start second demodulation based on the determination result of the first determination unit and a determination result of the second determination unit when the calibration period ends.

A communication system comprising:

• a data carrier apparatus;
• and a data carrier driving apparatus to be connected to the data carrier apparatus by two communication lines,
• wherein the data carrier driving apparatus includes:
• a modulation unit configured to generate a pulse signal modulated based on data to be transmitted;
• and
• a transmission unit configured to transmit the pulse signal generated by the modulation unit to the data carrier apparatus based on a potential difference provided between the two communication lines,
• the data carrier apparatus comprises:
• a first determination unit configured to determine a duty ratio of each pulse of a pulse signal received from the data carrier driving apparatus;
• a second determination unit configured to determine a frequency of each pulse of the received pulse signal;
• a calibration unit configured to perform calibration of a reference value to be used for determination performed by the second determination unit, during a calibration period;
• and
• a demodulation unit configured to demodulate data conveyed by the received pulse signal, the demodulation unit being configured to perform first demodulation based on a determination result of the first determination unit during the calibration period, and start second demodulation based on the determination result of the first determination unit and a determination result of the second determination unit when the calibration period ends, and
• the modulation unit generates a pulse signal in which the duty ratio of each pulse is modulated based on data to be transmitted during the calibration period, and the modulation unit starts generation of a pulse signal in which the duty ratio and the frequency of each pulse is modulated based on data to be transmitted when the calibration period ends.