My Printer Is Only Printing Half My Print?!

3rd June 2020 Printing

The Problem

Partial prints are a common issue with printers and there are several main reasons it can occur:

  • Problem with the print spooler (on Windows PCs)
  • Overload of the GPU on later model Macs
  • Dodgy USB cord
  • Dodgy USB port
  • Dodgy wireless connection
  • Skew detection or some other sort of automatic checking kicking in
  • Not using a fully blank piece of paper

We discuss each one and offer solutions & recommendations below.

Issues & Solutions

Sometimes there can be some left over data in your 'print spooler' - the temporary area data is stored in as it is handed off to the printer.  This can cause all sorts of issues with prints, including prints that only partially complete.

To fix a print spooler issue is relatively easy and this usually solves the problem.

  1. Click "start" and go to "Run"
  2. Type "services.msc" at the prompt which will open the Services window
  3. Scroll down the alphabetical list in the right window pane until you come to the entry with the name "Print Spooler
  4. Right-click this entry, then select "stop". This will stop the computer running the process that holds your print queues
  5. Leaving that window open for now, click again on "Start", and then click "My Computer" to open a Windows Explorer window
  6. We've stopped the queue service, now we just have to clear the jam that is already there. To do this we navigate to the print spool folder which is hiding within the Windows folders. Usually Windows is installed on C: drive, but you should be easily able to tell when the Explorer window opens which drive it is on.
    The usual path to the spool folder is C:\WINDOWS\system32\spool\PRINTERS, but yours may be slightly different. Your windows drive may have another name for instance, but this would be uncommon. So click on your Windows drive (usually C), then double-click on the Windows folder, and then find the System32 folder and double-click on that. Windows may warn you that you are about to view system files, but click "View files anyway" message and search out the "spool folder". Within the Spool folder is your Printers folder, and you should open that
  7. Delete every file within this folder to empty the jammed print queue (pressing the "ctrl" and "a" keys will select all files and then you can just hit "delete").
  8. Close the explorer window now that we have emptied the cleared spool files, and return to your Services window. we must re-start the Print spool service, and do so by right-clicking the Print Spool entry and selecting "Start" from the list. Close the services window and try printing again.

Overload of GPU on Macs

Recent MacOS versions (certainly from 10.15 on, but it might be the same for earlier versions too) - use the GPU (Graphics Processing Unit - i.e. video card) - for a lot more general processing, including spooling files to printers. 

If the GPU is overloaded, it can cause image processing during spooling to fail.  Unfortunately you don't get any particular warning or message about this....just another sheet of wasted paper!

In particular this often seems to occur in multi-monitor set ups with under-powered video cards. 

So try detaching any extra monitors as a first step.  And/or try closing any GPU intensive applications during printing (includes things like graphics / raw processing applications, but remember that modern browsers arealso  GPU intensive!).  

Dodgy USB Cord or Port

If you have tried to fix the GPU and/or print spooler issues as detailed above, and you are still having issues, it may be the case that your USB cord or port is not working correctly. Try a different USB cord or port and this will often solve the problem.

For Macs

If you've checked your USB connections, then you can sometimes solve persistent issues like this by resetting the entire print system, but please note: this loses all your printers & print settings and profiles - so it's quite a drastic solution.

Apple have a support note with the process here.

Dodgy Wireless

Wireless is great, but it's also a risky thing for devices requiring really continuous streams of data, like printers.

Many worry that wireless will slow their printer down - it won't.  Wireless is easily fast enough to keep up with the speed of the printer's head doing the printing, which is what limits your printer's speed in the general sense.  However, wireless IS perilous, because of consistency issues.

Printers, and particularly smaller printers, only have a relatively small internal buffer for print data.  They thus need a constant stream of new data to continue printing your print.  If this data files to arrive because a temporary wireless issue - the sort of wireless issue you might not even notice at all when e.g. browsing the net on your phone - then the printer will experience a buffer under-run error.   This means the printer is starved of the data it needs to keep printing.

Some printers will pause and keep trying, for a little while, but many will just give up at this point and spit out your half printed page.

So - the moral of the story is really to always use a wired connection if at all possible.  Even if not normally possible/easy, try a wired connection for a little while to see if it solves your problem - if it does, and you really do need to use wireless, then it is time to upgrade your wireless network to something more modern/better/consistent to solve these issues.

In general, the best hook-ups for printers are:

  1. Ethernet to a port on your network, with a fixed IP address assigned to the printer in your router.
  2. USB
  3. (...and a very distant 3.rd..) - Wireless

Skew Detection & Automatic Checks

Modern printers have various fancy features designed to 'help' you with your printing.

One of the most frequently frustrating is 'skew detection'.  Basically, the printer tries to detect if the page is not feeding perfectly squarely through the printer.  If it detects (often, it seems, incorrectly) - that the page is ever so slightly skew-iff, some printers will simply spit out the half done image at that point - and of course without even providing any sort of informative message.

Great design, huh?

Our advice is to turn off all of those sort of automatic checks - they usually do more harm than good.  We habitually turn off skew detection, automatic nozzle checking, and anything else it claims to automatically check.  Of course we do then run regular manual checks.  But in the case of, e.g. skew detection - I'd rather my print come out in full and be a mm or two not square on the page than waste a whole sheet of paper and ink when the printer decides three quarters of the way through that thing are screwy!

Always Use Blank Sheets of Paper!

A perfectly understandable inclination is doing a test print on a piece of paper, rotating it 180 degrees, and reloading that sheet for another test print at the other end of the sheet.

However, modern printers are absolutely full of sensors and this can stop your printer mid-print as the previosuly printed on part of the paper enters the printer and causes a sensor mis-read.

A much better approach is to e.g. split your A4 sheet (with a good rotary guillotine) - and then print on two blank A5 sheets instead. 

Some printers will even let you load something as small as A6, although you definitely do experience more paper loading problems with really small sheets, so we suggest sticking to the two A5s from one A4 approach which is a good compromise between not wasting paper and ink and not introducing too many challenges to your sanity in your workflow!

Rotatrim Rotary Trimmers
Rotatrim Trimmers - the industry standard rotary trimmers (guillotines) for various print sizes up to 1374mm (54"!) wide.
N.B. Please visit the full listing for important info on some variants.
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