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I'm using a thermal printer tm-t20 on 12.04 x64 with cups 1.5.3-0ubuntu4 and the Epson provided drivers tmt-cups-1.3.2.

The printer just prints garbage after the first print. If I turn it off and then on, it prints ok (the first Job), but if I send another job it prints just garbage. The printer is serial and I'm using an usb to serial converter, I tried with different adapter to discard an USB to serial converter issue.

At the cups web interface the following error is shown at job list:

"/usr/lib/cups/filter/pstopdf failed"

Part of the log:

[Job 15] Error: /dictstackunderflow in --end--

 [Job 15] Operand stack:
 [Job 15]
 [Job 15] Execution stack:
 [Job 15] %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2                   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1914   1   3   %oparray_pop   1913   1     3   %oparray_pop   1897   1   3   %oparray_pop   1787   1   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --             nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--

 [Job 15] Dictionary stack:
 --dict:1174/1684(ro)(G)--   --dict:0/20(G)--   --dict:77/200(L)--
 Current allocation mode is local
 [Job 15] GPL Ghostscript 9.05: Unrecoverable error, exit code 1
 [Job 15] PPD uses qualifier 'Gray..203x203dpi'
 [Job 15] Calling FindDeviceById(tmt20)
 Failed to send: org.freedesktop.ColorManager.Failed:device id 'tmt20' does not exists
 [Job 15] Failed to get profile filename!
 [Job 15] no profiles specified in PPD
D [30/Sep/2012:00:25:21 -0300] [Job 15] Ghostscript command line: /usr/bin/gs -dQUIET -dPARANOIDSAFER -dNOPAUSE -dBATCH -dNOINTERPOLATE -    sDEVICE=cups -sstdout=%stderr -sOutputFile=%stdout -r203x203 -dDEVICEWIDTHPOINTS=204 -dDEVICEHEIGHTPOINTS=841 -dcupsBitsPerColor=1 -         dcupsColorOrder=0 -dcupsColorSpace=3 -dcupsRowCount=24 -scupsPageSizeName=RP80x297 -I/usr/share/cups/fonts -c -f -_
D [30/Sep/2012:00:25:21 -0300] [Job 15] envp[0]="CUPS_CACHEDIR=/var/cache/cups"

I tried downgrading and upgrading cups (installing manually), but I wasn't able to send nothing to the printer because cups wasn't working (errors everywhere).

Any idea?

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Finally after a lot of pain. I discover that the problem was the serial to USB cable (in order to connect the serial printer to an USB port). I tried with two different serial to USB cables, but the problem persists and finally I conclude that The printer works erratically if is not connect to a "real" serial port.

I tested the printer under identical conditions in a PC with a serial port and it works perfect, just installing the driver provided by epson and giving chmod 777 to /dev/ttyS0. At the job list sometimes I see the error: "/usr/lib/cups/filter/pstopdf failed". But the printer prints ok, like no error occurred.

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