lprq error messages

waiting for printer to become ready (offline ?)
The daemon couldn't open the printer device. This can happen for several reasons (e.g., the printer is offline or out of paper, or the paper is jammed). The actual reason depends on the meaning of error codes returned by the system device driver; some printers can't supply enough information to distinguish when a printer is offline or having trouble, especially if connected through a serial line.

Another possible cause of this message is that some other process, such as an output filter, has an exclusive open on the device: all you can do in this case is kill off the offending program(s) and restart the printer with lprc.

printer is ready and printing
The lprq program checks to see if a daemon process exists for the printer and prints the file status located in the spooling directory. If the daemon isn't responding, the root user can use lprc to abort the current daemon and start a new one.
waiting for host to come up
This implies that there's a daemon trying to connect to the remote machine named host to send the files in the local queue. If the remote machine is up, lpd on the remote machine is probably dead or hung and should be restarted.
sending to host
The files should be in the process of being transferred to the remote host. If not, root should use lprc to abort and restart the local daemon.
Warning: printer is down
The printer has been marked as being unavailable with lprc.
Warning: no daemon present
The lpd process overseeing the spooling queue, as specified in the lock file in that directory, doesn't exist. This normally occurs only when the daemon has unexpectedly died. Check the error log file for the printer and the syslogd log to diagnose the problem. To restart an lpd, type:
lprc restart printer
no space on remote; waiting for queue to drain
This implies that there isn't enough disk space on the remote machine. If the file is large enough, there will never be enough space on the remote (even after the queue on the remote is empty). The solution here is to move the spooling queue or make more free space on the remote machine.