Lexmark International, Inc.

Christopher Alan Adkins

Michael Anthony Marra, Iii

Timothy Lowell Strunk

Timothy John Rademacher

Adam Jude Ahne

Barry Baxter Stout

Mark Joseph Edwards

Lucas David Barkley

Michael Clark Campbell

Stephen Porter Bush

Donald Fred Croley

Jay William Vessels

John Thomas Writt

Gregory Scott Woods

Stephen Kelly Cunnagin

Timothy P Craig

David Michael Cseledy

Michael Shayne Wilson

Douglas Keith Peterson, Jr

James Ronald Booth

Zachary Nathan Fister

Jennifer Topmiller Williams

John Dennis Zbrozek

Mark Walter Fagan

Mark Doerre

Nathan Wayne Foley

Alexander Lloyd Chapman

Graydon Randall Dodson

Jeffrey Ray Ehlert

Donald William Chapelle

Matthew David Clarke

Randall David Mayo

David Emerson Greer

Edmund Hulin James, Iii

Robert Henry Muyskens

Thomas Jon Eade

Patrick Laurence Kroger

David Allen Crutchfield

Kent Lee Ubellacker

Duane Edward Norris

Jason McReynolds

Douglas Laurence Robertson

Brian Jones

Bruce Lanier Walcott

Darell Dean Cronch

Paul Harrington, Iii

David Craig Stevenson

Nicholas Jon Post

Hugh Edwin Gilbert

George Chausanski

Eric David Langevin

Mark W Fagan

Renee Garcia, Jr

Alexander Phillip Maroudis

Dariush Aboonasry

Michelle Medina

Jonathan M Gumaroy

Israel Bautista

Thomas James Wack

Douglas Keith Perterson, Jr

Ellis Matthew King

Joshua Scott Potter

A supply item has toner for use in an imaging device. A chip has memory storing quanta indicating allowed usage of the supply item over its lifetime and a multiplier correlating the quanta to toner mass. The imaging device requires quanta to conduct imaging operations and loads the quanta and multiplier by way of a certificate stored in the memory. The imaging device retrieves quanta from the chip over time and both devices keep tally. Initialization between the supply item and imaging device includes providing encrypted and unencrypted instances of firmware versions and certificates from the supply item that the imaging device can compare for security. Alternatively, the supply item defines a fuser assembly, imaging unit, intermediate transfer member, or other component installed for use in the imaging device.

Method of setting up electrical communications between an imaging device and a supply item

Chip and supply item for imaging device, including communication

Methods for authenticating printer supply items using revocation lists are disclosed. Revocation lists are updated using DNSSEC to communicate between a printer and a DNS name server. A first domain name is created containing a request for a challenge to an authentication module and sent to the DNS name server. A second domain name is created containing a response to the challenge and sent to the DNS name server. The DNS name server indicates success or failure, which is used to authenticate the printer supply item. Other systems and methods are disclosed.

Systems and methods for authentication of printer supply items

Systems and methods for authenticating printer supply items using revocation lists are disclosed. Revocation lists are updated using DNSSEC to communicate between a printer and a DNS name server. A domain name is created containing a printer supply item serial number, a message digest, and a message authentication code. The domain name is sent to the DNS name server, and the returned IP address is used to update a revocation list. Other systems and methods are disclosed.

A method and apparatus for configuring an electronics device. The method includes receiving, by the electronics device, a request for a command to perform a predetermined operation by the electronics device and sending the command in response to receiving the request. The electronics device then receives a signature based upon the command, whereupon the electronics device verifies the signature by the electronics device and, following an affirmative verification, executes the command for performing the predetermined operation. In this way, the electronics device may be reconfigured remotely without knowledge of the particular command for performing the predetermined operation by the electronics device.

Method and apparatus for configuring an electronics device

Slave device circuitry, including processing circuitry which is configured to determine a new session identification value; determine a seed value using a secure hash algorithm on a previously determined seed value; determine a slave number from using the secure hash algorithm on the new session identification value, the determined seed value, and a serial number of the slave device associated with the slave device circuitry; receive a host number from the host imaging apparatus and calculate a session key using a hash-based algorithm computation on the host number, the slave number, the new session identification value, and a stored encryption key. The session key has a first portion for performing encryption and decryption operations on data to be transmitted and data received by the slave device, respectively, and a second portion for generating a new address value of the slave device for communicating with the host.

System and method for secured host-slave communication

The invention is directed to a tamper-evident method of encrypting data relating to one or more print cartridges installed in an imaging device that includes triggering a gathering of data relating to the one or more print cartridges installed in the imaging device; recording a number of instances the triggering is performed; retrieving a previously encrypted data relating to the one or more print cartridges installed in the imaging device, the previously encrypted data gathered at a time prior to the triggering; and encrypting the gathered data using the previously encrypted data.

Systems and methods of securing operational information associated with an imaging device

A new system and method for communicating between a host device and one or more slave devices are presented. The system provides data error checking and correcting, data encryption, and robust slave address sequencing using a portion of a session key. The data encryption uses a second portion of the session key, which changes for each power cycle.

The invention is directed to a method for performing failure analysis on an imaging device that includes retrieving an encrypted error log containing one or more error conditions that occurred on the imaging device, decrypting the retrieved encrypted error log, determining if the retrieved encrypted error log has been altered based on the decrypted error log, and upon determining that the retrieved encrypted error log has not been altered, performing failure analysis on the imaging device using the decrypted error log.

Systems and methods of verifying operational information associated with an imaging device

A master/slave data communication system in which a master device communicates with the slave devices by uniquely addressing each of the slave devices. In order to enhance the security of the data communication system, each slave device includes an address generator for generating unique addresses. Periodically, the master device requests that one or more slave device change its address. In response to the request, the addressed slave device increments its address generating algorithm to provide a new slave address. The master device also includes an algorithm that is synchronized with the slave address generating algorithm, whereby when the slave changes its address, it need not transmit the new slave address to the master device over the bus.

Dynamic address change for slave devices on a shared bus

A method of determining the state of a printhead/cartridge in a thermal inkjet printer. An inkjet printhead undergoes a jetting operation in which a jetting frequency is selected and a corresponding steady state printhead temperature is known. The printhead is heated to the steady state temperature. Then the printhead is jetted with all nozzles for a predetermined period of time. Temperature samples from the printhead are obtained and the change in the printhead temperature for a short period of time is used to determine a slope in the temperature change. From the slope of printhead temperature changes, the ink flow rate through the printhead can be determined. The flow rate of ink through the printhead can be used to determine the various states of the printhead, including out of ink, clogged, deprimed, a taped printhead, etc.

Method for measuring ink flow rate in an inkjet printhead

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Lexington, KY, United States of America

Christopher Alan Adkins