The picture above is a real-world example of a bar code label which has been allowed to enter the supply chain and has caused retailers & distributors problems at point of sale. This has been caused by a faulty print head.
Thermal printers render a much more accurate and faithful bar code image if you set them up to print in ‘picket fence’ orientation - this means that if you are standing in front of your printer, the bar code is presented in an upright position. The only problem with this is that if your print head deteriorates and a pixel or two fail, it may not be all that easy to spot with the naked eye without employing one of the following tactics:-
1. Print a solid line above the bar code.
Print a line all the way across your label. This can have a pleasing effect since it separates any text such as your product name or your company address from the bar code field. The purpose of the line is to alert you to any fault in the print head - as soon as a pixel fails, you will see a white line cutting through the black one. If it is offset from the bar code, you may choose to carry on using that print head, but as soon as any white line appears above the bar code, it’s time to change your print head!
2. Print a box around your code
This is also an effective indicator for print head fault alerts and can also look quite pleasing. Be careful not to make the code too ‘tight’ in the box since this can make the light margin too small - make the gap both sides of the code at least 7mm,
The print head on your thermal printer is a delicate component and recent studies have shown that only about 20% of owners undertake regular maintenance of their printers. Paper fibres and dust can be very abrasive and regular cleaning of the print head (to manufacturers instructions) can increase it’s life by a significant amount.