Draw11 - Printing Accuracy

[jduer]

When printing my drawings [on a HP LaserJet 5M or Lexmark Z11], the distance between vertical lines consistently print smaller than they should. The horizontal distances are fairly accurate measured by sight and a steel ruler.

Vertical measurements are a different story. With the line width is set to "Hairline", my eye estimates these distances to be anywhere from 1 to 3 line widths off depending up the size of the drawing.

The output of the Z11 displays a larger vertical error. This is something that I would expect from that type of printer, but I am puzzled by the 5M output. With 600 dpi printing accuracy, the 5M should be able to print at tolerances that should not be able to be seen easily by the eye.

There is a copy of some blocks that I created and saved to test with. If you are interested in pursuing this problem, you can download it from

http://www.judysquiltinginstructions.com/catalog/pub/testblock.doc.

Print this Word document on any or all printers at your disposal and check the results. I would be interested to know what discrepancies that you find and, of course, identify your printer.

Here’s what I get on my HP5M.

Block Size Measurements [Horizontal, Vertical]
1 5.5 x 10.0 h0, v 3 line widths short
2 2.0 x 8.0 h0, v 2 line widths short
3 2.0 x 2.0 h0, v 0 line widths short
4 1.0 x 5.0 h0, v 1 line widths short
5 2.0 x 5.0 h0, v 1 line widths short

There is some consistency is the measurements. The horizontal accuracy is difficult to measure by the eye and whatever its true value it is will within an acceptable range.

The vertical discrepancy is easily identified and appears to get larger as the vertical size increases.

The puzzling part of this question is “Whose problem is it?” and is it solvable? Since I get two different results from two different printers, obviously the printers bear some fault, but is it totally a printer problem?
I ran another test using Draw11 to create and 10” x 10” block. I then printed it on both the HP and Z11 printers as the block was created and then rotating the block 90 degrees counterclockwise. The printer size results were the same in [short by about 1/64”] either case. Of course I could not print the full block horizontally. This leads me to believe that 100% of the problems lie with the printers.

Any comments, similar experiences or guesses of things to try will be appreciated.

Joe Duerstock

 

[Brushman]

I use a HP 5000 A3 printer for printing onto laser film for positve litho plates and regularly to 2 and 3 colour jobs with tight registration with no problem what I have found is that the printer can take a page to 'warm up' so 1st page is a dummy then I print the job. My printer is also 1200 as opposed to 600 and also the media you print on will have a bearing. The film is much more stable than paper.
Regars
Alan

 

[jduer]

Brushman:

Your ending comment about the stability of the film provided the hint that I needed to get my head looking toward where the problem really is – the heat of the LaserJet combined with the moisture content of paper causes the paper to shrink.

I never could reconcile that a printer with a dpi of 600 and the feed mechanism of the LaserJet could produce output whose size was so incorrect. On the other hand, I don’t see how an inkjet printer could ever come close to the printing accuracy of a LaserJet.

So here’s “a” solution, however inelegant. I “preshrunk” the paper by using Word to print the same blank page 3 times. Then I waited until the sheet had cooled before I printed the drawing. Although the result was not 100% accurate, it was well within my expected tolerances.

It seems that all paper comes with a certain percentage of moisture in it and I reckon for most applications some moisture is needed for proper operation.

I ran further tests and determined that running the paper through the printer once gives the same accuracy as running it 3 times.

Thanks again.

Joe Duerstock

 

[Brushman]

I glad you can get round your problem, at the end of the day we must remember that we are using relatively cheap equipment and media for the job a very expensive image setter does. I'm pleased I could help anyway.
Alan