Headstrikes are produced when the head drags across the media and either smears the printed image or smears ink from the bottom of head onto the media.
The most common causes of headstrikes are:
- Too little clearance between the head and the media (head height)
- Excessive heat on the media
- Sudden humidity changes when printing on paper
- Too much ink on paper
- Incorrect loading or feeding
- Incorrect or poor quality media.
Most thin paper and vinyl materials can be used at the machine's lowest head height setting. However, depending on the characteristics of the media, some wrinkling (cockling) may always be present. If that is the case, increase the head height until you no longer see head strikes during operation.
On solvent printers, the heaters themselves can cause cockling of adhesive vinyls and banner materials. Some materials are stable up to 50C but many adhesive vinyls begin to buckle at temperatures as low as 35C.
For cockling, the most important heaters to control are the pre heater (which softens the vinyl) and the platen heater (which is located directly below the print head path).