ZPL batch print ship label issues...memory limit? - zebra-printers

We have a web app that batches the ZPL for many shipping labels (UPS, USPS, FedEx) at a time. For some reason it will randomly mis-print where is just prints the barcodes, but nothing else. This usually only starts after about label 20 or so in the batch, and even then, it is not consistent in the labels after that. Sometimes it does it, sometimes it doesn't. It is consistent in that it does it to the USPS labels and not UPS or FedEx.
If we reprint just that label's zpl, it prints fine.
So I was wondering if there is some limit we're running into with batching. We send just one long zpl string for the entire batch, each label separated with ^XA....^XZ.
The printer is a GX420T.
Any ideas?
Example mis-print - I drew black lines on the barcodes to make them not readable for privacy

Related

I want to print an incremental count on the top right corner of my labels from my Zebra printer using ZPL

I currently know how many labels I want to print and use ^PQ# to print that amount but the trouble is getting an incrementing count printed on the corner of each label.
There are a couple problems right now. First is that Zebra doesn't have anything letting me print the odometer value on the zebra printer. It will kind of let me print the number of centimetres or inches using ~WQOD, but it comes with a lot of extra information that I don't want. I couldn't find any commands in the manual just letting me print the number of labels with the reset-able odometer.
I could create a counter outside of the printer then send a request to print each label with a new number on the top right, however, that overloads the printer and causes connection issues with the printer if I print too many labels.
Are there any ways to overcome either of those issues so I can print an incrementing counter on each label?
The command to print a sequence of numbers across labels is ^SN. It is specifically used with ^PQ.
^SN001,1,N^FS
^PQ3
To not overload the printer, send all individual labels within one connection, as a single string stream, don't open a separate connection for each.

ZPL Can I trick the printer into thinking I printed two labels?

I have a label stock that has two labels side by side, so I've written my code to print identically on both of these labels.
The issue is that a printer sees this as one label, but I need it to see them as two. How then, could I possibly trick the printer into thinking two labels have been printed?
If ZPL can print 2 separate pieces of code on one label this might be possible. If there's a command that makes a single label count as 2 then it's definitely possible.

Estimate ZPL Render And Print Times

I am working on a set of ZPL validation routines which parse arbitrary ZPL files, sanitize them, edit certain key commands (label length, print speeds, etc), and extract some useful information.
Since this printer is generating labels for a free-running shipping line I really need to know how long it's going to take from the moment I send the ZPL file to the printer until I'll be ready to apply the label. It is clear that the print time is directly linked to the label length and print speeds, but the label render time (conversion of ZPL into ready to print image in printer memory) is less obvious.
Since I'm printing label contents provided by numerous third parties, I can't simply measure the time for the labels. I've asked Zebra and gotten no guidance, so I'm wondering if anyone has an idea of how to estimate the render time? Am I stuck trying to estimate the processing time of every individual ZPL command?
My experience over the last couple of years working with differnt zebra printers (Z4M, ZM400, GK420t) is, that the label that is send to the printer is printed almost instantaneously.

Which should not be included in this ZPL Code?

I am developing a Windows Mobile App that requires printing into a Zebra printer. Problem is, I do not have the printer with me here in my country since the client did not provide any.
My approach was to design a label first in ZebraDesigner2, then print out the label into a text file. Printing the label to a text file instead of a printer sends out the ZPL Code to produce the label I was trying to print. Hence, I can generate ZPL codes faster by designing a label first then seeing the ZPL code. Kinda like having a drag and drop GUI with a background XML.
Say that I have this simple label that contains this text:
Hello World!
If I print this in ZebraDesigner2 it would be written to my text file as:
CT~~CD,~CC^~CT~
^XA~TA000~JSN^LT0^MNW^MTT^PON^PMN^LH0,0^JMA^PR5,5~SD15^JUS^LRN^CI0^XZ
^XA
^MMT
^PW609
^LL0406
^LS0
^FT1,29^A0N,28,28^FH\^FDHello World!^FS
^PQ1,0,1,Y^XZ
My main question is, which one do I include in my C# Code if im going to send this code to the printer via my Windows Mobile C# app? Do I include the part with ^XA until ^XZ? I believe that CT~~CD,~CC^~CT~ should not be included in my code If im not mistaken.
Late answer, but since this is getting viewed...
The CT line and first set of XA..XZ sequence sets up the modes, label length, printable area, etc.
If you remove those, it will take those settings from the label/printer settings, which is usually what you want. The printers can sense the length and width of the label.
Leaving them in can cause big problems, because if you define the printable area in your label, and then the next label type submitted does not, it will use the settings you have defined -- which can cause blank areas in the label, eg. cutoff USPS Label barcodes that are printed after your Zebra Designer custom labels.
Found this out the hard way - leave those out, and you should leave out of the remaining XA..XZ sequence the MMT, PW609, LL0406, and LS0 as well - your Hello World will not be affected.
If you really want to limit the area printed to, set up margins inside the printable area, etc, refer to the manual.
you have to look at the programmers guide before you remove anything of the code. The CT~ command for example changes the control prefix.
Search the internet or zebra.com site for "ZPL Programming guide".
So, leave the text file as is and then include that into your windows mobile application.
PS: zebra offers SDKs for label/receipt printers: http://www.zebra.com/gb/en/products-services/software/adapt-software.html
PS2: without a test printer you may get bad final results.

Printing a graphic to a Zebra LP2844 with the GW EPL command?

I need to print an image that is being returned to me through a web service (the data is returned as RAW) and I cannot for the life of me figure out how to print a graphic to a label with EPL.
The EPL manual defines the Graphic Write instruction as:
GWp1, p2, p3, p4, DATA
All of the parameters are returned to me, so I don't have to worry about calculating the height, width, etc., but my problem is that I don't know how to format the DATA.
The manual says DATA should be
Raw binary data without graphic file formatting. Data must be in bytes.
I've tried passing a binary string and a hex string, but nothing seems to work. There is no example on how to use this command in the EPL manual and after hours of searching online I have not been able to find a single example of how to use the command (i.e. example EPL commands that I can copy & paste to send to the printer).
Does anyone have an idea of how to use this command? Could you provide me with an example? (by example I don't mean a framework, code, etc., what I mean is just the plain EPL commands).
I can confirm that the data is in raw, uncompressed binary. It is also inverted-- that is, the 0 bits print as black, at least on my UPS-firmware LP-2844. I have no idea why all the examples from Zebra show the data as encoded into a hex representation.
It's worth noting that most print servers (HP Jetdirect, Lantronix LPS1-T, and almost certainly the Zebra built-in and external print servers) will form a binary connection to the printer if you spit data at them on port 9100 (using netcat for example):
nc printer_hostname_or_ip_address 9100 < test_file.txt
You get no feedback from the printer, except for the label having printed or not.
It takes my LP-2844 (UPS Firmware) printer about 5-6 seconds to print a label containing a 816 wide x 1218 tall downloaded bitmap onto a 4" wide x 6" tall label. It seems to be all imaging time: sending three labels at once is not any faster, and the network connection (through a Lantronix LPS1-T) is held open until the final label prints. That image is at the native resolution of the printer (203 dots/inch), and there is no dithering or resizing going on (I don't think EPL2 even knows how to dither or resize).
It might be possible to speed up the imaging time by optimizing the label into many smaller bitmaps (and horizontal and vertical line segments, and perhaps filled-in rectangular blocks). This wouldn't be a very hard optimization because the image is a single-bit black and white bitmap, and the code would be fairly simple. I don't know if it would really speed it up, though.
A more modern Zebra GX420 running ZPL with a built-in ethernet port ($500 online) can print the same label (with essentially the same graphic download encoding) in 1-2 seconds.
By the way, since I haven't yet actually answered the question, the raw EPL code for this is:
(a blank line)
N
q816
Q1218,20
GW10,10,102,1218,(124236 bytes of inverted bitmap data)
P
all the newlines are 0x0a (unix-style).
Maybe this will help, it has examples (and corrects an error in the manual). Also, it may be easier to use the GM command instead and just delete the image each time (see here for a stackexhange related question).
That being said, I've never gotten my Eltrons to successfully print an image (but my jobs don't require it).
Good luck!!
EDIT: Here's another link with example Perl code. They're aiming for Chinese characters but show how to print the Great Wave image (which oddly is Japanese).
I found that it is not possible to send a graphic to a Zebra printer with EPL using ASCII characters. The data must actually be sent as RAW data. So, for example, you can't send a graphic to the printer using Zebra Setup Utilities, or through any other means that cannot write RAW data from a file directly through the printer.
The only way around this I've found is to create the label as an image and send that image to the printer via a print command within your application.

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