Supply cartridge for a printing apparatus

A method of operating a set of printing machines, each printing machine using a removable cartridge, comprising the steps of:

• for a first subset of printing machines, providing a first population of cartridges, each of the first population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle, and wherein each of the cartridges comprises means defining an opening, the opening disposed substantially at a center of the circle;
• for a second subset of printing machines, providing a second population of cartridges, each of the second population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle;
• for each of the first and second population of cartridges, the plurality of engagement structures together occupying no more than half a circumference of the circle;
• wherein the engagement structures of the first population of cartridges are physically distinguishable from the engagement structures of the second population of cartridges.

A method of operating a set of printing machines, each printing machine using a removable cartridge, comprising the steps of:

• for a first subset of printing machines, providing a first population of cartridges, each of the first population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle;
• for a second subset of printing machines, providing a second population of cartridges, each of the second population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle;
• for each of the first and second population of cartridges, the plurality of engagement structures together occupying no more than half a circumference of the circle;
• wherein, for the first and second population of cartridges, each of at least a subset of the engagement structures define at least two contact structures, and wherein the two contact structures are separated by a separation angle around the circle;
• and
• wherein the separation angle associated with the first population is different from the separation angle associated with the second population.

A method of operating a set of printing machines, each printing machine using a removable cartridge, comprising the steps of:

• for a first subset of printing machines, providing a first population of cartridges, each of the first population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle;
• for a second subset of printing machines, providing a second population of cartridges, each of the second population of cartridges including means defining a plurality of engagement structures, the engagement structures arranged around a circle;
• for each of the first and second population of cartridges, the plurality of engagement structures together occupying no more than half a circumference of the circle;
• wherein the cartridges of the first population include engagement structures which are arranged radially symmetrically around a circle and the cartridges of the second population include engagement structures which are not arranged radially symmetrically around a circle.