| US 7,585,043 B2 | ||
| Method of authenticating a consumable | ||
| Christopher A. Adkins, Lexington, Ky. (US); Michael C. Campbell, Lexington, Ky. (US); Donald F. Croley, Georgetown, Ky. (US); and Timothy L. Strunk, Lexington, Ky. (US) | ||
| Assigned to Lexmark International, Inc., Lexington, Ky. (US) | ||
| Filed on May 18, 2005, as Appl. No. 11/131,881. | ||
| Application 11/131881 is a division of application No. 10/431485, filed on May 06, 2003, granted, now 7,240,995. | ||
| Prior Publication US 2005/0206672 A1, Sep. 22, 2005 | ||
| Int. Cl. B41J 29/393 (2006.01) | ||
| U.S. Cl. 347—19 [347/5; 347/7] | 10 Claims |
| 1. A method of authenticating a consumable having a memory and used in an imaging device, comprising:
performing a first renewal of said consumable;
generating a first authentication code configured both for authentication and for signifying said first renewal; and
storing said first authentication code in said memory of said consumable;
performing a second renewal of said consumable;
generating a second authentication code configured both for authenticating and for signifying said second renewal; and
storing said second authentication code in said memory of said consumable;
wherein said first authentication code is generated using a first algorithm and said second authentication code is generated
using a second algorithm, the first and the second algorithm uses a secret key that depends upon type of ink being used in
the imaging device; and
wherein said second algorithm uses said first authentication code in generating said second authentication code.
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