Thermal printhead mechanism

• US 6,672,780 B2
• Filed: 09/21/2001
• Issued: 01/06/2004
• Est. Priority Date: 09/21/2001
• Status: Expired due to Fees

• Current Assignee: Panduit Corporation
• Original Assignee: Panduit Corporation
• Inventors: Adams, Michael Scott, Yehl, Gregory C.
• Primary Examiner(s): Hirshfeld, Andrew H.
• Assistant Examiner(s): Ghatt, Dave A.
• Application Number:
  US09/960,050
• Publication Number:
  US 20030059241A1
• Time in Patent Office: 837 Days
• Field of Search: 400/55, 400/56, 400/58, 400/354, 400/120.01
• US Class Current: 400/58
• CPC Class Codes: B41J 2/32 using thermal heads
• CPC Class Codes: B41J 25/308 with print gap adjustment mechanisms
• CPC Class Codes: B41J 25/3086 with print gap adjustment means between the print head and its carriage

Abstract

The invention is a thermal printhead mechanism having a stationary spring channel, a top bracket supported by the spring channel, and a printhead mounted to the top bracket. Additionally, the invention may include a cam, a bottom bracket, and a front mounting plate.

Claims

1. A thermal printhead mechanism comprising:

a spring channel fixed in a stationary location;

a pair of independent resilient members supported on said spring channel;

a top bracket movably supported on said pair of independent resilient members, a first point of said top bracket being supported by a first of said pair of independent resilient members and a second point of said top bracket being supported by a second of said pair of independent resilient members; and

a printhead secured to said top bracket;

wherein said printhead secured to said top bracket may translate toward and away from said fixed spring channel by uniform expansion and contraction of said pair of independent resilient members to accommodate differing media thicknesses and may also rotate such that said first and second points of said top bracket are at different distances from said fixed spring channel by differential expansion and contraction of said pair of independent resilient members to accommodate media of non-uniform thickness.

2. A thermal printhead mechanism in accordance with claim 1 wherein said top bracket is formed in a generally U-shaped configuration.

3. A thermal printhead mechanism in accordance with claim 1 wherein at least one of said independent resilient members is a compression spring.

4. A thermal printhead mechanism in accordance with claim 1 further including a bottom bracket supported by said top bracket.

5. A thermal printhead mechanism in accordance with claim 4 further including a cam mechanism disposed between said spring channel and said bottom bracket.

6. A method of maintaining a substantially uniform contact pressure between a platen roller and a printhead secured to a top bracket when a print medium of uneven thickness is inserted therebetween, said method comprising the following steps:

securing a spring channel in a fixed location;

supporting a pair of independent resilient members on said spring channel; and

supporting said top bracket on said pair of independent resilient members, a first point of said top bracket being supported by a first of said pair of independent resilient members and a second point of said top bracket being supported by a second of said pair of independent resilient members;

wherein said printhead secured to said top bracket may translate toward and away from said fixed spring channel by uniform expansion and contraction of said pair of independent resilient members to accommodate differing media thicknesses and may also rotate such that said first and second points of said top bracket are at different distances from said fixed spring channel by differential expansion and contraction of said pair of independent resilient members to accommodate media of non-uniform thickness.

7. A method in accordance with claim 6 wherein said top bracket is formed in a generally U-shaped configuration.

8. A method in accordance with claim 6 wherein at least one of said independently resilient members is a compression spring.