White spots on substrate

Hi, I'm using the HP Latex 370 printer and the media is Orafol Orajet 3164. I'm using the preset given from HP, but I still get white spots on the print, especially when printing blue. Is there a solution to this problem. We already replaced the optimizer head.

Hi @fabricate13121,

This seems to be related to an IQ defect _ Pin holing. To minimize this effect, I suggest increasing the optimizer level. I hope this helps.

Hi Daniela, Thank you for the response. But, can you please link to a guide on how to increase optimizer level ? and What is IQ defect -Pin holing ? Sorry, if these are novice questions, but the local HP technicians did not help us much.

Hi @fabricate13121,

To increase the optimizer level: go to control panel > substrate > settings. Increase by 5 from the value you have for this substrate (see image 1). Judging by the images it looks more like Pin- holing, but it can also be coalescence.

Here is the procedure for each of them:

1. Pin-Holing: Blank holes in the black, not saturated areas. This is more visible in zones with 20% to 50% of black. The effect is like coalescence but keeping some holes. Suggestion: Increase the OPtimazer level (see image 2).

2. Coalescence: Typically caused by poor spreading and drying of ink, causing small ink drops to coalesce. This is due to an excessive amount of ink, and the ink being misplaced as it is deposited on the substrate. It can also be caused by firing too much ink in a short time. Coalescence is most likely to be seen in areas of high ink density. Suggestion: decrease print zone temperature, if not fixed Increase the number of passes_if not fixed Decrease ink density (see image 3).

I hope it helps.