Method of calibrating a spatial light modulator printing system

• US 5,842,088 A
• Filed: 01/06/1997
• Issued: 11/24/1998
• Est. Priority Date: 06/17/1994
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Thompson, E. Earle
• Primary Examiner(s): Braun, Fred L.
• Application Number:
  US08/781,999
• Time in Patent Office: 687 Days
• Field of Search: 399/177, 399/2, 399/48, 399/51, 399/52, 347/142, 347/237, 250/252.1
• US Class Current: 399/177
• CPC Class Codes: B41J 2/435 characterised by selective application of radiation to a printing material or impression-transfer material
• CPC Class Codes: B41J 29/393 Devices for controlling or analysing the entire machine ; Controlling or analysing mechanical parameters involving printing of test patterns
• CPC Class Codes: G03G 15/04045 for exposing image information provided otherwise than by directly projecting the original image onto the photoconductive recording material, e.g. digital copiers G03G15/041, G03G15/043 take precedence
• CPC Class Codes: G03G 15/0856 Detection or control means for the developer level
• CPC Class Codes: G03G 15/326 by application of light, e.g. using a LED array
• CPC Class Codes: G03G 15/50 Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control sequencing control G03G21/14
• CPC Class Codes: G03G 15/5033 by measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor
• CPC Class Codes: G03G 15/55 Self-diagnostics; Malfunction or lifetime display
• CPC Class Codes: G03G 15/553 Monitoring or warning means for exhaustion or lifetime end of consumables, e.g. indication of insufficient copy sheet quantity for a job
• CPC Class Codes: G03G 21/1875 provided with identifying means or means for storing process- or use parameters, e.g. lifetime of the cartridge
• CPC Class Codes: G03G 21/1878 Electronically readable memory
• CPC Class Codes: G03G 21/1882 details of the communication with memory, e.g. wireless communication, protocols
• CPC Class Codes: G03G 21/1889 for auto-setting of process parameters, lifetime, usage
• CPC Class Codes: G03G 2221/1663 having lifetime indicators
• CPC Class Codes: G03G 2221/1823 Cartridges having electronically readable memory
• CPC Class Codes: G03G 2221/1838 Autosetting of process parameters
• CPC Class Codes: G06K 15/1238 simultaneously exposing more than one point
• CPC Class Codes: H04N 1/19 using multi-element arrays
• CPC Class Codes: H04N 1/1906 Arrangements for performing substitution scanning for a defective element
• CPC Class Codes: H04N 1/233 according to characteristics of the data to be reproduced, e.g. number of lines
• CPC Class Codes: H04N 1/2338 : according to user specified instructions, e.g. user selection of reproduction mode
• CPC Class Codes: H04N 1/2346 : according to a detected condition or state of the reproducing device, e.g. temperature or ink quantity
• CPC Class Codes: H04N 1/295 : Circuits or arrangements for the control thereof, e.g. using a programmed control device, according to a measured quantity

Abstract

A method for calibrating a printing system using a spatial light modulator. The spatial light modulator is an array of individually activated elements, all of which are set in a predetermined state, such as the ON state. Light is then directed onto the array and the resultant light passed into the printing system from the modulator is monitored by a sensor. Discrepancies between the light expected and received at the sensor are used to adjust the operation of the modulator to compensate for stuck or non-responsive pixels.

Claims

1. A method for calibrating a spatial light modulator printing system, comprising:

a. activating all of the elements of a spatial light modulator to a predetermined state, where said predetermined state is the same state for all elements, each time said printing system is turned on;

b. impinging light upon said modulator;

c. monitoring light received from said modulator at a sensor, such that elements that are defective are identified by discrepancies in the light received from individual elements that is different than what was expected from those individual elements; and

d. adjusting the operation of said modulator to correct any defects in printed image caused by said defective elements, using other elements in a same column as those defective elements.