Transfer printer and method

A method for monitoring a characteristic of a printed image of a thermal transfer printer, comprising:

• providing a ribbon and a substrate at a printing location of the thermal transfer printer;
• printing an image on the substrate at the printing location by transferring ink from a region of the ribbon in a printing operation, a negative image being formed on the region of the ribbon;
• transporting the region of the ribbon, by a ribbon transport system, from the printing location towards an imaging location along a ribbon transport path;
• determining whether a characteristic of the ribbon transport meets a predetermined criterion,
• in response to determining that the characteristic meets the predetermined criterion, obtaining, by an image capture system, a ribbon image of the negative image;
• and
• processing said ribbon image to generate data indicative of a characteristic of the printed image;
• wherein said characteristic of the ribbon transport comprises an acceleration of the ribbon transport, and wherein the characteristic of the ribbon transport meets the predetermined criterion when the acceleration is below a predetermined threshold.