Thermal printhead having asymmetric recording elements

Patent metadata

Field	Value
Publication number	US-10787000-B2
Application number	US-201715856433-A
Country	US
Kind code	B2
Filing date	Dec 28, 2017
Priority date	Dec 28, 2017
Publication date	Sep 29, 2020
Grant date	Sep 29, 2020

Abstract

An asymmetric thermal print head includes a print head body and a plurality of print elements supported on the print head body. The print elements are aligned along a first axis. Each print element includes a heater portion having a burn width measured along the first axis corresponding to a first print resolution, and a burn length measured along a second axis, which is perpendicular to the first axis, corresponding to a second print resolution. The second print resolution is higher than the first print resolution. One or more control circuits are configured to individually activate the print elements.

First claim

What is claimed is:

1. An asymmetric thermal print head for printing images to a substrate by heating and transferring portions of a print ribbon to the substrate, the thermal print head comprising:
a print head body;
a plurality of print elements supported on the print head body and aligned along a first axis, each print element including a pair of electrodes that are spaced apart from one another and a discrete heater portion between and coupled to the pair of electrodes, the discrete heater portion having a burn width measured along the first axis and a burn length measured along a second axis that is perpendicular to the first axis, the burn length defined by a spacing between the pair of electrodes, wherein the burn length is shorter than the burn width, such that the print elements are configured to produce a first print resolution corresponding to the first axis that is lower than a second print resolution corresponding to the second axis; and
one or more control circuits configured to individually activate the print elements and to produce the first print resolution along an axis of the substrate parallel to the first axis and the second print resolution along an axis of the substrate parallel to the second axis.

2. The thermal print head according to claim 1 , wherein the second print resolution is approximately double the first print resolution.

3. The thermal print head according to claim 2 , wherein the first print resolution is approximately 300 dpi, and the second print resolution is approximately 600 dpi.

4. The thermal print head according to claim 3 , wherein the burn width of each heater portion is approximately 3.33 mil and the burn length of each heater portion is approximately 1.67 mil.

5. The thermal print head according to claim 1 , wherein the print elements are divided into separate groups, the one or more control circuits includes a plurality of control circuits, and each control circuit is configured to control activation of individual print elements within one of the groups.

6. A method of printing an image on a substrate comprising:
printing an image line on a surf ace of the substrate comprising printing a plurality of pixels using an asymmetric thermal print head, each pixel having a pixel width measured along a first axis aligned with the image line, and a pixel length measured along a second axis that is perpendicular to the first axis;
shifting the print head relative to the substrate along the second axis a distance corresponding to the pixel length; and
repeating the printing an image line and shifting the print head a limited number of times to complete the printing of the image on the substrate;
wherein the asymmetric thermal print head comprises:
a print head body;
a plurality of print elements supported on the print head body and aligned along a first print head body axis, each print element including a pair of electrodes that are spaced apart from one another and a discrete heater portion between and coupled to the pair of electrodes, the discrete heater portion having a burn width measured along the first print head body axis and corresponding to the pixel width and a burn length measured along the second axis and corresponding to the pixel length, the burn length defined by a spacing between the pair of electrodes, wherein the burn length and corresponding pixel length are shorter than the burn width and corresponding pixel width, respectively, such that the print elements are configured to produce a pixel arrangement along the first axis having a first print resolution that is lower than a second print resolution of a pixel arrangement along the second axis; and
one or more control circuits configured to individually activate the print elements and to produce a lower print resolution along the first axis than the second axis.

7. The method according to claim 6 , wherein printing the image line comprises printing pixels having a pixel width that is approximately double the pixel length, and the second print resolution is approximately double the first print resolution.

8. The method according to claim 7 , wherein:
the pixel width is approximately 3.33 mil, and the pixel length is approximately 1.67 mil;
the first print resolution is approximately 300 dpi; and
the second print resolution is approximately 600 dpi.

9. The method according to claim 8 , wherein the burn width of each heater portion is approximately 3.33 mil and the burn length of each heater portion is approximately 1.67 mil.

10. The method according to claim 8 , wherein
printing the image line comprises selectively activating the resistive heating elements of the print elements to print the plurality of pixels.

11. The method according to claim 10 , wherein:
the print elements are divided into separate groups;
the one or more control circuits includes a plurality of control circuits, and each control circuit is configured to control activation of individual print elements within one of the groups; and
activating the resistive heating elements of the print elements comprises activating the individual print elements within each of the groups using one of the control circuits.

12. A credential production device comprising:
a print ribbon; and
an asymmetric thermal print head configured to print an image to a surface of a substrate using the print ribbon, the print head comprising:
a print head body;
a plurality of print elements supported on the print head body and aligned along a first axis, each print element including a pair of electrodes that are spaced apart from one another and a discrete heater portion between and coupled to the pair of electrodes, the discrete heater portion having a burn width measured along the first axis and a burn length measured along a second axis that is perpendicular to the first axis, the burn length defined by a spacing between the pair of electrodes, wherein the burn length is shorter than the burn width, such that the print elements are configured to produce a first print resolution corresponding to the first axis that is lower than a second print resolution corresponding to the second axis; and
one or more control circuits configured to individually activate the print elements and to produce the first print resolution along an axis of the substrate parallel to the first axis and the second print resolution along an axis of the substrate parallel to the second axis.

13. The device according to claim 12 , wherein the second print resolution is approximately double the first print resolution.

14. The device according to claim 13 , wherein the first print resolution is approximately 300 dpi, and the second print resolution is approximately 600 dpi.

15. The device according to claim 14 , wherein the burn width of each heater portion is approximately 3.33 mil and the burn length of each heater portion is approximately 1.67 mil.

16. The device according to claim 15 , further comprising a substrate processing device selected from the group consisting of a substrate rotator, a data encoder, a laminating unit, and a magnetic stripe reader and writer.

17. The device according to claim 12 , wherein the substrate is a credential substrate and wherein the device further comprises:
a credential substrate supply containing a plurality of credential substrates; and
a transport mechanism configured to feed credential substrates from the supply along a processing path.

18. The device according to claim 12 , wherein:
the substrate is an intermediate transfer layer; and
the device further comprises a laminati

Assignees

• Assa Abloy Ab

Inventors

• Lien Brent

Classifications

• B41J2/36

  Print density control · CPC title

• B41J2/33545

  characterised by dimensions · CPC title

• B41J2/3354

  characterised by geometry · CPC title

• B41J2/3357 Primary

  Surface type resistors · CPC title

• B41J2/3351

  Electrode layers · CPC title