Browse Prior Art Database

Automatic Thermal Printer Calibration

IP.com Disclosure Number: IPCOM000048227D
Original Publication Date: 1981-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Dyer, S: AUTHOR [+2]

Abstract

A calibration site is located along the print line of a thermal ribbon printer, preferably at one end, and includes a thermal sensor for detecting ribbon temperature. During calibration operation, a drive pulse having a preselected waveform is applied to the printhead and special logic adjusts the reference level for the normal drive waveform based on the resulting ribbon temperature.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 95% of the total text.

Page 1 of 2

Automatic Thermal Printer Calibration

A calibration site is located along the print line of a thermal ribbon printer, preferably at one end, and includes a thermal sensor for detecting ribbon temperature. During calibration operation, a drive pulse having a preselected waveform is applied to the printhead and special logic adjusts the reference level for the normal drive waveform based on the resulting ribbon temperature.

Referring to the figure, a printhead 10 is arranged to engage a ribbon 12, and drive signals D supplied by drivers 14 are applied by electrodes 16 to cause selective localized heating (see exploded view).

For normal printing, control signals P are supplied by a print control 18 to time the occurrences of respective drive signals D. Calibration occurs at a particular site and, for example, might occur after each line return as signaled by a printhead position control 20 that is connected to calibration logic 22.

When in the calibration mode, a preselected waveform for drive signals D is triggered by predefined signals P and a predefined reference signal REF applied to the drivers 14. The temperature is detected by a sensing device 24 that engages the ribbon 14 at the calibration site. An analog-to-digital (A/D) converter 25 converts the output of the sensing device 24 to a coded signal that provides the calibration logic 22 with a value for entering a storage 26 for a table of reference signal levels to identify a signal REF to be applied to the...