Here’s the long & the short of the main differences & which is suitable for what.
What is continuous printing?
Continuous printing utilises rolls of paper (also known as a web). It’s a form of web printing that was specially developed to produce continuous stationery for processing through sprocket-fed printers and later evolved to include the production of elements for direct and transactional mail. It’s ideal for high-volume print runs that require further processing through high-speed printers.
What is sheet-fed printing?
As its name indicates, sheet-fed (also known as cut-sheet) involves feeding individual sheets of paper into a press. Sheet-fed printing is ideal for projects requiring larger, heavier and speciality papers. It also offers a much better range of finishing options, and is ideal for short-to-medium print runs.
The quantity / speed / cost equation:
Sheet-fed doesn’t have the same overheads or set-up, make-ready and waste costs as continuous. The tipping point is where sheet-fed becomes more expensive than continuous.
All the considerations:
Continuous presses need more make-ready and waste. They generally cost more than sheet-fed presses and take up more factory floor space, so the overhead recovery is also higher. Sheet-fed presses require less set-up and waste and take up less factory space.
Continuous presses tend to be more expeditious at handling larger quantities, bigger runs and multi-part jobs. Sheet-fed presses tend to be better at smaller, more specialised runs.
As continuous is generally limited to uncoated, porous stocks, the printing tends to lack the vibrancy of sheet-fed. Sheet-fed presses are the perfect go-to for projects that are more concerned with enhanced quality.
In continuous, the plate is wrapped around the cylinder and the ends of the plate are locked into place, creating a no-print area known as plate-gap (normally 10mm). With sheet-fed the gripper edge is the edge of the paper (the leading edge) that enters the printing unit first. The grippers hold tightly to the paper and create a print-free strip of about 3/8".
With continuous the sheet size is dependent on the width of the press and the circumference of the cylinders on that specific press. 24” (610mm) tends to be the most common size. Sheet-fed presses can run a larger sheet size, with many being able to run A1 or even A0.
Continuous handles bond and cartridge-type stocks best and paper is normally limited to lower weights. Sheet-fed can print on much thicker paperstocks, as well as on coated stock and speciality papers.
Continuous generally uses infra-red (IR) or ultra-violet (UV) ink drying which enables rewinding of the reel of paper. Sheet-fed generally uses air drying, so sheets need time to dry adequately before further processing can take place.
If further processing is required, continuous can be finished to fan-folded packs or reels, or can be sheeted and bound. Sheet-fed is suitable for a wide range of offline finishing processes (eg, foiling, varnishing, folding and binding).
Continuous (fan-fold or reel) is ideal for high-speed continuous laser printing and offers a larger sheet-size (more or less A2). Sheet-fed printing can only be laser printed through sheet-fed laser printers, which are usually limited to A3 in size.
Continuous printing is ideal for large runs on uncoated stocks – eg, business forms and documents, direct mail and transactional mail. Sheet-fed is ideal for short and medium print runs that require more paper and finishing options – eg, letterheads, business cards, brochures, leaflets and calendars.