Decoding thermal printer head data (interleaved 4-phase structure?)

[carrot6614]

Hi all,

I'm analyzing a thermal printer head using a logic analyzer and trying to understand how the pixel data is encoded.

Observations:
- Data is sent in 4 chunks of 8 bits per column (total 32 vertical dots)
- The data corresponds to left-to-right scanning
- When I split the data into even/odd bits and reorganize it, I get 4 separate bitmaps
- When these 4 layers are interleaved, they form a coherent character (example: Japanese "い")

This suggests that the printhead might use some kind of interleaved multi-phase driving scheme.

Questions:
- Is this a typical structure for thermal printheads?
- Is this related to current limiting or strobe multiplexing?
- Are there known architectures that explain this kind of data layout?

I've attached:
- Logic analyzer captures
- Extracted bitmaps showing the 4 layers

Any insights would be greatly appreciated.

[carrot6614]

I’m really sorry—it was a misunderstanding on my part. I may have assumed that comparing digital data to printed materials was the correct approach. In reality, printing may not have been possible, and I may have simply been looking at something I had printed in the past. That might be why I was so troubled by the discrepancy. Anyway, now that I have a plan for driving the thermal head, I’ll move on to the next step. Thank you.