I print A grade barcodes on my PVC cards but C grade barcodes on my PE cards. Sometimes it degrades on other PVC cards also. What is going on ?
Since the surface tension varies from product to product, the DOD ink that will fall on that surface will behave differently: contracting if the surface tension is below 36 (Dynes per cm), expanding if it is above.
That is why, one can print C grade barcodes on a product, clean or plasma treat the product, and you will print A grade barcodes on the same product. With the plasma, you convert a surface from say 30 to 35. It is a play between the substrate and the ink.
Now, if you declare for example a code 39 code to be 3 drops wide for the thin bar and thin space, and 9 drops wide for the wide bar and wide space, you will get different results on different substrates without touching the inkjet.
Above is the ideal, the print looks like the layout, the bars are as wide as the corresponding spaces.
Drop contracts print: width in thin/wide bars black and is the same; a < b. Compensate thicker !
If you print this wider bar and thinner space on a substrate on which the drop contracts, you will compensate for that and get closer the ideal dimensions ? a=b
If the bar is still thinner than the space, you can add another dot. You also raise the ink temperature by 5C to see whether the ink flows better. If you have a plasma treater, you can switch it on.
Drop expands print: width in thin/wide bars black and is the same; a > b. Compensate thinner !
If you print this thinner bar and wider space on a substrate on which the drop expands like absorbent paper, you will compensate for that and get closer the ideal dimensions ? a=b
If the bar is still wider than the space, you can subtract/add another dot.