Method and apparatus for storing data in a non-volatile memory circuit mounted on a printer's process cartridge
US5995774A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1998 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Sep 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2221/1663
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved electrophotographic (EP) printer is provided having a detachable process cartridge that contains a non-volatile memory device, which is an EPROM that cannot be erased after a bit is burned. A "toner wheel" mounted to the exterior of the toner reservoir of the process cartridge provides, in conjunction with an optoelectronic sensor, an electrical signal that the printer receives and uses to determine toner usage. A toner "gas-gauge" is created which uses "bucket levels" as discrete steps to indicate how much of the measured physical toner material actually remains within the toner reservoir. After a given amount of toner material has been dispensed through the developer unit, one of the bits of the EPROM memory device is irreversibly burned, thereby providing a permanent record on the process cartridge of a certain amount of toner usage. As with a normal automobile gas gauge, the toner gas-gauge reading should never increase unless the amount of toner material inside the toner reservoir has increased. Once the bucket level transitions begin to occur for the toner gas-gauge, the printer becomes aware that a majority of the toner material has been expended from inside the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.