Blotchy output on one side of a dye-sub print usually points to a contact/alignment problem rather than an image issue. Based on the symptoms, the most likely causes are:

• a dirty print head
• wrinkles or creases in the ribbon/media that lift it away from the print head
• a misaligned or damaged print-head assembly, possibly from the printer being dropped

Since cleaning did not help, and physically moving the printer/assembly improved the result, misalignment is a strong possibility. Uneven pressure or spacing across the head can cause one side to print weakly or inconsistently.

Also inspect the media path and ribbon for wrinkles, creases, or anything preventing full, even contact. If the problem stays limited to one side after cleaning and checking media, the printer may need mechanical adjustment or repair.