Heat Time

[mungle]

Hello!
I've installed a mini thermal printer in a 5V 2.5A power supply. Everything works but text and images (also the test page on switch-on holding the button) is very light... I need a darker output. How to set up an "Heat" propriety?

Thanks

[XAS-712]

If the printer supports, you can use a higher voltage.
Or you can open it and find its power supply circuit.

[klirichek]

You can play with fork of @belese
As I see he tried to add a kind of 'wait' commands into a flow to achieve darker print.
(however the ESC commands he uses looks unknown for me; m.b. he has kind of hacked firmware on the printer).

[belese]

for info it's not fully finish (at least not clean code), most option should work if i remember, i use a cheap printer on ebay, i don't know about the firmware it used. and i use a python driver now.
Otherwise, you can use python command to change heattime before using the cups drivers, i was doing like that before. and printer keep it's config after a reboot, at least mine, so you can do it only one time

example
https://github.com/belese/polapi/blob/master/polapi/resources/thermal.py#L65

and the wait command is like darker print is slow, and i use uart without dtr, i need to send data not too fast, or data is lost and printer print garbage.

[klirichek]

@belese, I just seen that you use some kind of printer codes like ESC '8' to achieve something.
What is it? Where it is documented? That is the only thing made me curious.
(I don't even think about to made a delay between lines of raster, since, who knows, may be next filter (backend) of cups will anyway buffer them and send 'as a batch'. But this one I found in no docs).

(btw, in kind of modern influence - you can write your filter on Go. It is compilable ).
Also, in flavour of having all the settings in the ticket (no need to parse/reparse PPD, all is in input data) it could be even simplier to work with)

[belese]

i've used that docs.
https://cdn-shop.adafruit.com/datasheets/A2-user+manual.pdf

and probably a mix of python driver with that.
it's a long time ago for me, i don't remember what i've done, and have no idea about how work cups before i've do that, so probably i don't do it in the good way.

After a quick look in code, where do you see i use ESC 8, i use ESC 18 for print density.