A printing machine for printing on a printing substrate web includes a plurality of inline flexographic printing units which are disposed in a plane accessible to an operator of the machine. Each one of the two flexographic printing units of a respective duplex printing station includes a respective impression cylinder and a dryer disposed between the two impression cylinders along a path of web travel of the web of printing substrate. A method of operating the printing machine is also provided.

A method of forming an array of microimage elements that vary in their material composition is provided. The method comprises: applying a first region of a layer of a first material to a surface of a first material carrier; applying a second region of a layer of a second material, different from the first material, to a surface of a second material carrier; blending together the first and second regions of the layers of first and second material such that a blended region of the layers of first and second material exhibits a gradual change in relative concentration of the first and second materials along a first direction, the step of blending together the first and second regions of the layers of first and second material comprising bringing a first blending surface into contact with the first material on the surface of the first material carrier and moving the first blending surface relative to the surface of the first material carrier along a direction corresponding to the first direction to spread the layer of first material along the direction corresponding to the first direction, and bringing a second blending surface into contact with the second material on the second material carrier and moving the second blending surface relative to the surface of the second material carrier along a direction corresponding to the first direction to spread the layer of second material along the direction corresponding to the first direction; bringing the blended layers of first and second material in the blended region into contact with a patterned material carrier, the surface of the patterned material carrier defining a pattern corresponding to the array of microimage elements, the patterned material carrier selectively removing the first and second material in at least the blended region in accordance with the pattern; and transferring the blended layers of first and second material defining the array of microimage elements on to a support layer.

A printing system comprising a flexographic printing machine comprising at least one impression cylinder, on which the material in sheet form to be printed is wound and around which at least one printing station is arranged. Each printing station comprises a plate cylinder, which is provided with a graphic element, and an anilox roller. Downstream of each printing station there is at least one drying unit for the inks which emits at least one first air flow and aspirates at least one second air flow; there are also elements for acquiring a coverage value of the graphic element present on the plate cylinder of each printing station and elements for automatically adjusting a flow rate of the first air flow and of the second air flow as a function of the coverage value of the graphic element acquired by the acquisition elements.

A printing machine for printing on a printing substrate web includes a plurality of inline flexographic printing units which are disposed in a plane accessible to an operator of the machine. Each one of the two flexographic printing units of a respective duplex printing station includes a respective impression cylinder and a dryer disposed between the two impression cylinders along a path of web travel of the web of printing substrate. A method of operating the printing machine is also provided.

A security device includes an array of microimage elements formed of at least a first material and a second material, the microimage elements of the array being integrally registered with one another. The material composition of the array of microimage elements varies across the array along a first direction such that the array of microimage elements exhibits a gradual change in relative concentration of the first and second materials along the first direction.

A security device includes an array of microimage elements formed of at least a first material and a second material, the microimage elements of the array being integrally registered with one another. The material composition of the array of microimage elements varies across the array along a first direction such that the array of microimage elements exhibits a gradual change in relative concentration of the first and second materials along the first direction.

A printing system comprising a flexographic printing machine comprising at least one impression cylinder, on which the material in sheet form to be printed is wound and around which at least one printing station is arranged. Each printing station comprises a plate cylinder, which is provided with a graphic element, and an anilox roller. Downstream of each printing station there is at least one drying unit for the inks which emits at least one first air flow and aspirates at least one second air flow; there are also elements for acquiring a coverage value of the graphic element present on the plate cylinder of each printing station and elements for automatically adjusting a flow rate of the first air flow and of the second air flow as a function of the coverage value of the graphic element acquired by the acquisition elements.