Method, device and computer program to correct a registration error in a printing process that is due to deformation of the recording medium

A printing system device to correct a registration error in a printing process, comprising:

• a raster image processor which generates first and second raster graphics structured in rows and columns with data of a first respective image and data of a second respective image;
• a print member or two respective print members receiving control data from the respective first and second raster graphics;
• the print member printing on a recording medium a first print image in a first printing process with the control data from the first raster graphic;
• a treatment unit for subjecting the recording medium and the printed first image thereon to a deformation which deforms the medium and the printed first image by a deformation factor at least around one deformation axis;
• the at least one printing member or the other of the two printing members printing the recording medium with a second print image in a second printing process with the control data from the second raster graphic;
• and
• a processing system to avoid a registration error between the first and the second printed images and which processes the control data of the respective raster graphic of at least one of the first and second print images as a source image along an image processing axis of the respective raster graphic that corresponds to the deformation axis and wherein respective source pixels to be used for the respective raster graphic being selected stochastically from the source image in a direction transverse to the image processing axis.

A method to correct a registration error in a printing process, comprising the steps of:

• subjecting data of first and second images to be printed to a raster image process via which at least respective first and second raster graphics structured in rows and columns are generated;
• respectively forming control data for a print member or two respective print members from the respective first and second raster graphics;
• printing a recording medium with a first print image in a first printing process with the control data of the first raster graphic;
• subjecting the recording medium to a treatment via which said recording medium and the printed first print image are deformed by a deformation factor at least along one deformation axis;
• printing the recording medium with a second print image in a second printing process with the control data of the second raster graphic;
• and
• to avoid a registration error between the first and second printed images, processing the data of the raster graphic of at least one of the first or second print images as a source image along an image processing axis of the respective raster graphic that corresponds to the deformation axis, wherein a target pixel is calculated from respective adjacent source pixels of the source image according to a predetermined calculation rule wherein n is a whole number greater than one, and a proportion of process pixels along the image processing axis corresponds to the deformation factor.