A system for manufacturing large quantities of seamed belts for printing systems with controlled imageable seams, which belts require a defined circumference and width, from suitable belt material in a large roll thereof, by feeding a continuous web of that belt material from the roll in (or cut to) a width that is at least as wide as the defined circumference of the finished seamed belt into a seam cutting station, where the opposing side edges of the continuous web of belt material are cut as they move through the seam cutting station into opposing seam-forming mating edge patterns, preferably mating puzzle-cut patterns cut by small movement laser beams on each side of the moving web. The moving web is then wrapped over a mandrel surface so that the opposing side edges of the web are brought together while said continuous web of belt material is moving, mating the opposing edge patterns together to form a belt seam in a moving tube of the web material, the belt seam is adhesively sealed, and then increments of this moving tube are intermittently transversely cut off to the selected width of the finished seamed belt.