Ink Rolls can snap when they come into contact with a dirty thermal head.  The hot head causes the built up dirt to "melt" on the ink roll and this can cause it to snap, and stick to the paper roll. 

Gently remove the ink cassette, pulling any ink roll stuck to the paper away at the same time.  Cut the ink roll edges with scissors to make straight edges. Overlap the edges and join with sticky tape.  Roll the ink roll forward on the cassette to the used side.

Here's a link to a video: how to repair a torn ink roll

Dye sublimation printers work by using a precision thermal head. If dirt gets on the head it can cause the head to not make contact. The results are lines on the pictures. 

To resolve this issue, all you need is some Isopropyl alcohol from Bunnings (use it with a soft silky cloth) or Medi-Swabs from the chemist to clean your head.

Simply, open the printer and whip the head with it. Here is a video on how. 

The white lines on the edges of printers are caused by the paper not being moved through the machine in a consistent rate. The main cause of this dust on the rollers that feed the paper though the printer. The dust stops the roller from grabbing the paper correctly. 

To fix this you need you will need buy or make an exit roller cleaning sheet. These are thick plastic sheets with an adhesive side on them. Feed the sheets thought the exit roller section of the printer. Be sure to make sure you bend the plastic sheets back or they will get stuck. Here is a video with detailed instructions on how to do it.  

No. Its not recommend that you ship your printer with media in it. Most damage happens during transit and media can be huge cause it. These printers are precision devices with very very very tolerances. Having heavy media inside while in transit can cause warping and change tension on the springs.  

Here is quick video about it

Yes. The scrapes have line dust and parts on them. These can move during transit. Plus the scrapes can get lodged in the belts and rollers as well. 

Mitsubishi recommend emptying before opening the door the printer too. 

Actually, yes. The paper is key the whole printing process. Believe it or not heat, humility and water can damage the pager. 

Most people don't know this but it's not actually paper, It's plastic. so heat can affect way more than normal paper.