Machine for printing images on articles by means of a thermal transfer roller

A printing machine—for printing images on articles, comprising:

• a supporting structure, stationary in operation,
• a thermal transfer assembly movable in a predetermined horizontal direction and comprising a rotatable motorized transfer roller and heating means associated to the rotatable motorized transfer roller wherein rotatable motorized transfer roller has at least one outer layer of synthetic material with a peripheral surface facing a path of the articles and wherein rotatable motorized transfer roller and the associated heating means are movable vertically in said thermal transfer assembly towards and away from said path of the articles, and
• supply means arranged to advance, along a predetermined path extending in part between the active surface of rotatable motorized transfer roller and the path of the articles, a flexible printing ribbon which on a side facing the articles carries at predetermined intervals images formed of a thermally transferable ink,
• wherein the thermal transfer assembly further comprises first and second deviation rollers, whose axes of rotation are horizontal and substantially parallel with one another and with a axis of rotation (x) of rotatable motorized transfer roller and are also orthogonal to said predetermined horizontal direction, said first and second deviation rollers being placed one upstream and the other one downstream of rotatable motorized transfer roller on the path of said printing ribbon and being vertically movable in the thermal transfer assembly towards and away from said path of the articles,
• characterized in that said printing machine further comprises first and second motor means associated with said first and second deviation rollers, respectively, said first and second motor means being controllable independently of one another such that each of said first and second deviation rollers is selectively movable vertically independently of the other one, further comprising an electric motor coupled with rotatable motorized transfer roller via a unidirectional joint to cause the rotation of rotatable motorized transfer roller in a predetermined direction, whereby while the thermal transfer assembly is moved relative to the supporting structure along said predetermined horizontal direction corresponding to a direction of rotation of rotatable motorized transfer roller, the unidirectional joint allows rotatable motorized transfer roller to rotate to a highest speed among a speed imparted to rotatable motorized transfer roller by the electric motor and a speed imparted to rotatable motorized transfer roller as a result of the translational movement of the thermal transfer assembly.