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Label printing problems

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by sootie607

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I hope someone can help me!
We use Zebra printers (i work in the manufacturing industry) to print labels with barcodes. The Zebra printer will print different amounts of labels (from 1 - 11) then stop for 1 - 5 minutes and then continue. This is a massive problem if when we are printing hundreds of labels a day.
I'm using the following hardware and software;

Windows 2000 server SP4
Zebra Z6M + printer with Seagull Scientific drivers connected to LAN with Axis 5550 print server.
100 Mbps LAN
Streamserve EDI software

I've tried the following;
Changing the print server
Changing the print drivers
Attaching the printer locally to the server
Changing spool settings eg print directly to printer etc
Changing cables and ports on the LAN
Changing the spool folder location
Many other things!!

I think it must be something to do with the Windows print spooler. Anyone any suggestions? Sort this out and I'll buy you a beer!

Cheers

10 replies

by stress junkie

I've seen printer problems occur when the networked printer dropped its connection to the print server in the middle of a print job. I don't have a networked printer in front of me right now but I'll wing it.

Problems can occur when the following happens. The print server has a large print job for a given printer. The print server sends part of the job to the printer but the printer's memory fills up before it can load the entire print job. The printer starts printing the job in its local buffer. The amount of the print job in the printer's local memory takes a long time to print because the printer has a lot of local RAM. During the time that the printer is processing the information in its RAM the printer server network connection times out and is dropped. When the printer finishes printing the data in its local memory it asks the printer server to send more. This requires the printer server to restart the job and skip ahead to the unprocessed part of the print job.

This kind of network time out between a networked printer and the print spooler can cause several kinds of problems. The one that you mention, where the printer pauses for a long time, is typical of this type of configuration. Another problem that can arise from networked printers dropping their connection to the printer server is that the printer may reset its print job settings back to their defaults. This could lead to the first part of a print job being printed in one font and the remaining parts printed in another font.

This problem is caused by two concurrent conditions on the printer. First, the printer has a lot of local RAM. Second, the printer drops its connection to the printer server before it prints everything in its local buffer.

The preferred resolution to this problem is to increase the network connection keepalive time on the printer. The printer should have a setting for this. It would either be labelled "keepalive" or "timeout". The network connection keepalive time has to be longer than it takes the printer to print a full buffer.

Another solution is to reduce memory in the printer. The end result is the same. The printer will keep the network connection alive longer than it takes to print a full buffer.

Lastly, you could restrict the size of your print jobs to less than the size of the buffer on the printer.

by sootie607

This problem also occurs with small print jobs. 16 labels @ 30k each =480k, (i think my maths is right!). The printer has 4Meg RAM so the entire job should fit in the print buffer easily.
I do recall something about only 11 TCP ports being allowed to be opened and not reused for 4 mins, i think it was something to do with RFC compliance. But I think this only applied to NT not 2000?
Also i can't find anything to do with keepalive/timeout settings on the printer. Could the keepalive settings be on the print server?

Thanks

by walter.cox

Got any pc's clogged w/spyware flooding the network w/packet traffic? Also, how about your network cable run between the printer and the switch? Move the printer to another location and see what you've got. Another idea would be to buy an inexpensive print server and us it in place of your current one to see if that resolves the issue...

Just a few more ideas, good luck!

by sootie607

There are no network problems (spyware, viruses etc) and I've tried the printer in different locations. The original print server was a DLink DP301+ and I replaced that with a more expensive Axis 5550 (more onboard RAM to eliminate possible buffer problems).
Keep the ideas coming!

by tony hopkinson

But I bypassed the windows printing completely and accessed the printers serially through com ports. This was way back when on NT4, but I had a lot of problems with windows printing and 'non standard' label/stamping boxes. Stuff like it form feeding after each single label. Eventually I got so dischuffed with the zebra stuff I just got the maunal out and sent the escape strings straight down the wire, worked like a charm and it did what I needed not what ms wanted.
You should be able to do the same thing over TCP/IP. Zebra used to provide some label design software with the facility to save the escape sequences in a file.

by sootie607

Can you explain about the escape strings/sequences and what you did. The label design software is part of the 'Streamserve' package, are you familiar with this and could i save the escape sequences in there?

by tony hopkinson

what I had was the manual for the zebra printer. Then I wrote a program in delphi to wrap the content of a database query in the command strings and then force it down the serial port. Might even have the program somewhere but this was 1997.

A bit later on we upgraded the printers and we got a 'free' piece of label design software. I then used this to visually design labels, output them as raw text and the pasted the escape strings into my code.

Long time ago but the strings did things like set font face and size position a 'cursor' out put text in a font or as a bar code etc.

Laborious but easy, if you've got the manual for your model. Zebra will have it somewhere.
The label design software took what you've dropped onto the gui and then converts it into a series escape strings, sort of like HPs PCL. You could view it as an unreadable strange form of xml.

by esq

If your Zebra supports the EPL or ZPL programming language, you can send concatenated escape strings directly to the printer using Zebra Setup Utility.

Is upgrading to Win 7 an alternative for you? I tested the Zebra GX430t (check out the reviews at http://printing.it-enquirer.com) within XP and 7 and it worked like a charm, using Zebra's own drivers.

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