The main reason for the unclear printing of bar code printers is that the print head needs maintenance. The print head of the bar code printer is the most critical maintenance and replacement part. Improper use or maintenance of the print head will affect the print quality and cause direct causes such as insufficient black, excessive black, streaks, and spots. Regular cleaning and replacement of necessary parts is the best way to ensure stable print quality and performance.
1. The bar code printer prints too brightly (not dark enough)
If the black bar code is printed too lightly, it will not be able to form sufficient contrast with the light-colored areas. This will directly affect the scanning device to read data.
The reasons and solutions for the printing are not dark enough:
a. The pressure applied by the print head to the material is uneven or insufficient. The solution is to adjust the pressure of the print head.
b. The heat of the hot label material or the melting belt in the thermal transfer is not high enough. The heating setting is adjustable and should be adjusted to produce the desired contrast.
2. The bar code printer prints too dark
When the heating setting is too high, too much black will appear and the barcode will become thicker, also known as barcode hyperplasia. This will cause the barcode to fail to meet the specifications because the required width/width ratio cannot be maintained and may become unreadable.
Solution: Lowering the thermal setting can usually correct excessive blackening.
3. Extra diagonal lines appear in the printed pattern
The appearance of redundant diagonal lines or white stripes is an error signal for ribbon installation or transportation.
Solution: The ribbon should look smooth when inspected. Ensure that the label material is correctly installed within the lead range and fed into the printer smoothly and evenly.
4. Spots or gaps appear on the printed pattern
Generally, dust, pits, or defects on the print head can cause spots and voids. Defects hinder heat transfer and cause blind spots on the label. Dust or corrosion spots can also prevent or change the direction of heat or ribbon transfer, causing gaps or spots, making the barcode unreadable.
Solution: Regular cleaning can prevent dust and corrosion spots
5. The edges of the printed patterns of the barcode printer are blurred
Bar code readers need clear edges to identify lines and spaces and appropriate decoding symbols. One of the factors that make thermal technology the best barcode printing technology is the ability to produce straight and clear edges. Reducing the printing speed can usually correct rounded or blurred edges. Low-quality label or ribbon material, or ribbon and media mismatch can also cause blurred edges. Printing barcodes in the vertical (trapezoidal) direction may also cause blurred edges, so printing should be done in the horizontal (stacked) direction as much as possible.
Solution: Many of these quality issues can be monitored, such as normal visual label inspection, or printing a test label every time a barcode printer is started, shifting changes, media or ribbon changes. These preventive measures can prevent problems and form the basis for an effective quality assurance program.
6. Solutions to unclear printing caused by other problems:
a. The print head needs to be replaced.
b. When printing, the crumpled ribbon can also cause streaks or blind spots.
c. If the strap is not tight enough, it may bend and make the strap taut.
d. If the ribbon continues to wrinkle and fold, the printing speed may need to be reduced.
e. Other possible causes of spots or voids include improper coatings or other defects on the top surface of the media. Try a new media volume and see if the problem persists.
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