Printing is faint.
If the printing is faint, check the following.
1. Check printing surface of TPH. (When the overall printing is faint or only one side is faint)
1-1. Foreign substance on TPH could make the printing faint.
1-2. Check and clean the printing surface with Cleaning Pen.
1-3. If the printing quality does not change after cleaning, check the following.

2. Check the paper (When the overall printing is faint)
2-1. Printing quality very much depends on the quality of the paper.
2-2. Check the printing quality using highly sensitive paper.

3. Adjusting printing density
3-1. All types of thermal printers have functions to adjust the printing density.
3-2. You can check the printing density settings by checking the settings of Dip S/W with User Manual, and adjust the density accordingly.
3-3. If you make the printing density too high, it could reduce the lifespan of TPH.

4. When one side is faint or white lines are produced
4-1. Clean the printing surface as described in step 1 above.
4-2. If one side is severely faint or white lines are produced, contact the service center as the problem could be mechanical deformation or troubles in TPH or main board.