Ribbon wrinkle The ribbon wrinkles and cause blank streaks on the finished label. This can happen at any time, during a run or at the start after the printer has sat for a while. Is this related to the downward pressure on the printhead or the ribbon tension?

1. The printhead in your printer might be scratched (evidenced by thin white streaks through your print). This is common, and the most likely cause. Printhead must be replaced.
2. Material might be stuck on your printhead (usually evidenced by wide white streak vertically through print). Printing surface of printhead can be cleaned with rubbing alcohol and cotton ball.
3. The ribbon might be wrinkling due to uneven tension, producing intermittent diagonal streaks in your print. This is somewhat common, but doesn't fit your description as well as 1 & 2 above. Mechanical adjustment and/or proper media loading solves ribbon wrinkles.
4. Poor pressure and/or printhead alignment. Evidenced by grainy, light or no print on one side or the other of the media. This is somewhat common, but doesn't fit your description as well as 1 & 2 above. Mechanical adjustment solves printhead pressure and alignment issues.

Its probably not static. 1. Wipe the print head and platen roller with alcohol dampened qtip or lint free cloth. Print about 30 labels while gently pressing on the ribbon supply, causing it to drag a little and observe if the wrinkles stop. If so tighten the nut on the end of the ribbon supply a little at a time until wrinkles disappear. Check the head pressure toggles on top of the print head and make sure they are adjusted about the same. If you have been printing a lot of the same size labels, check the platen roller (white) at the point where the right edge of the label rides on it for a slight offset where the roller is worn down. If it is worn, the only fix is to replace the platen roller.

If streaks are perfectly vertical and always present, probably your printhead is scratched and needs to be replaced. Unless the streaks are diagonal and intermittent - then you need adjustment for ribbon wrinkle.
Printheads

Definitely. possible solution match the width of your label and ribbon. if your ribbon is wider for .5 inch it should be good.
1. check your spindle alignment, printhead alignment and rotate the green knob on the printhead while printing so that you'll see the difference.

Could be down to tension on the ribbon roller/spool. Check to see if you have pulled out the end part of the spool (black bit) that should ensure there is back tension on the ribbon.

The thermal print head is damaged. You can try to clean it with a thermal printer head cleaner. That will only help if it is just clogged up with thermal print ink.

Remove the ribbon and try to remove the crease. Check the printhead for obstructions. You may have to open up both halves of the ribbon cartridge to look for jams or obstructions.

I changed the print head, and the issue was solved.

Printer ribbon has a wrinkle and it transfers to the label in the form of a blank line accross the ribbon.

This is usually caused by temperature of the thermal print head. This is found in the printing preferences of the printer.