DragonFly BSD

handbook-printing-troubleshooting

11.7 Troubleshooting

After performing the simple test with lptest(1), you might have gotten one of the following results instead of the correct printout:

It worked, after awhile; or, it did not eject a full sheet.:: The printer printed the above, but it sat for awhile and did nothing. In fact, you might have needed to press a PRINT REMAINING or FORM FEED button on the printer to get any results to appear. If this is the case, the printer was probably waiting to see if there was any more data for your job before it printed anything. To fix this problem, you can have the text filter send a FORM FEED character (or whatever is necessary) to the printer. This is usually sufficient to have the printer immediately print any text remaining in its internal buffer. It is also useful to make sure each print job ends on a full sheet, so the next job does not start somewhere on the middle of the last page of the previous job. The following replacement for the shell script /usr/local/libexec/if-simple prints a form feed after it sends the job to the printer:

#!/bin/sh
#
# if-simple - Simple text input filter for lpd
# Installed in /usr/local/libexec/if-simple
#
# Simply copies stdin to stdout.  Ignores all filter arguments.
# Writes a form feed character (\f) after printing job.
/bin/cat && printf "\f" && exit 0
exit 2

It produced the staircase effect.:: You got the following on paper:

!"#$%&'()*+,-./01234
                "#$%&'()*+,-./012345
                                 #$%&'()*+,-./0123456

You have become another victim of the staircase effect, caused by conflicting interpretations of what characters should indicate a new line. UNIX® style operating systems use a single character: ASCII code 10, the line feed (LF). MS-DOS®, OS/2®, and others uses a pair of characters, ASCII code 10 and ASCII code 13 (the carriage return or CR). Many printers use the MS-DOS convention for representing new-lines. When you print with DragonFly, your text used just the line feed character. The printer, upon seeing a line feed character, advanced the paper one line, but maintained the same horizontal position on the page for the next character to print. That is what the carriage return is for: to move the location of the next character to print to the left edge of the paper. Here is what DragonFly wants your printer to do:

Printer received CR Printer prints CR
Printer received LF Printer prints CR + LF

Here are some ways to achieve this:

Printer receives Printer prints
CR CR
LF CR + LF The printer lost characters.:: While printing, the printer did not print a few characters in each line. The problem might have gotten worse as the printer ran, losing more and more characters.

The problem is that the printer cannot keep up with the speed at which the computer sends data over a serial line (this problem should not occur with printers on parallel ports). There are two ways to overcome the problem:

Then, try printing again. Check the log file (in our example, /var/log/rattan.log) to see any error messages that might appear. Based on the messages you see, try to correct the problem. If you do not specify a lf capability, LPD uses /dev/console as a default.

CategoryHandbook CategoryHandbook-printing

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