Relief printing plate manufacturing method, relief printing plate creating apparatus, and recording medium

A relief printing plate creating apparatus creating a relief printing plate by laser engraving, the apparatus comprising:

• a binary image data generating device configured to generate binary image data based on multivalued image data representing a printing image;
• an engraving target shape data generating device configured to generate, from the binary image data, target stereoscopic shape data as an engraving target;
• an exposure amount data generating device configured to calculate, based on the target stereoscopic shape data, exposure amount data, based on which an output of laser light by a laser engraving machine is controlled;
• an edge exposure amount setting device configured to provide a predetermined exposure amount to an outside image adjacent pixel in a range of predetermined pixels adjacent to an ON pixel corresponding to an image part of the binary image data;
• and
• a laser engraving device configured to apply laser light to an area of OFF pixels corresponding to a no-image part of the binary image data on the plate based on the exposure amount data to engrave a portion surrounding an area to be left on the plate as the image part, and to apply laser light to the outside image adjacent pixel on the plate based on the predetermined exposure amount set by the edge exposure amount setting device to form a relief having a projecting shape with a corner part of a flange part of a top face of the relief corresponding to the image part at least partially chamfered.

A non-transitory computer-readable recording medium including instructions stored thereon, such that when the instructions are read and executed by a processor, the processor is configured to perform the steps of:

• a binary image data generating step of generating binary image data based on multivalued image data representing a printing image;
• an engraving target shape data generating step of generating, from the binary image data, target stereoscopic shape data as an engraving target;
• an exposure amount data generating step of calculating, based on the target stereoscopic shape data, exposure amount data, based on which an output of laser light by a laser engraving machine is controlled;
• and
• an edge exposure amount setting step of providing a predetermined exposure amount to an outside image adjacent pixel in a range of predetermined pixels adjacent to an ON pixel corresponding to an image part of the binary image data.