Patent ID: 8128186

Claim:
A printing system for selectively depositing visible material on print media, the printing system comprising: a print mechanism configured to receive a replaceable printing component, the print mechanism including a control portion for transferring data between the print mechanism and the replaceable printing component; and a replaceable printing component including an electrical storage device responsive to printing system control signals for selectively storing information received from the print mechanism, the electrical storage device including: a storage portion containing data associated with the replaceable printing component; and first and second validation fields configured to store error detection codes relatable to the data contained in the storage portion to determine whether the data is valid; wherein the electrical storage device is configured, prior to a first transfer of data from the print mechanism to the storage portion, to receive and store in one of the first and second validation fields a first error detection code related to the data currently contained in the storage portion, and the electrical storage device is configured to receive and store in the other of the first and second validation fields a second error detection code related to the data that will be contained in the storage portion after the first data transfer; and wherein the control portion is configured to transfer, to the first validation field, the second error detection code related to the data that will be contained in the storage portion after the first data transfer and to transfer, to the second validation field, a third error detection code related to the data that will be contained in the storage portion after a second data transfer successively following the first data transfer.