Creasing versus Scoring
There are several methods of scoring paper or card substrates. However, we will focus on the two most common processes today – rotary scoring and creasing.
Scoring
Most standalone rotary scoring and perforation machines today are air-fed and have a rotary scoring wheel included or available as an option. Traditional rotary scoring devices use circular blades or wheels that are in constant motion as the stock passes through them. This creates a ploughing action, which scores by breaking the surface and fibres of the paper. This makes rotary scoring suitable for unprinted paper as well as some printed material in which the ink is absorbed into the sheet (offset), unlike digital toner which sits on the paper surface. With traditional offset, rotary scoring is not a problem. The ink is absorbed into the paper and has no difficulty flexing to allow the paper to bend around the scoring wheels. In almost all cases, a rotary score should be in the same grain direction as the paper to achieve the maximum quality.
The appeal of rotary scoring is its high speed as the sheet does not need to stop. Scoring wheels can be applied to folding machines before folding. Add cross-fold attachments, and the sheets can also be scored as they change direction. Varying thicknesses of scoring wheels can also be attached. Generally speaking, the thicker the card or paper, the thicker the score will have to be in order to allow the substrate to bend without cracking. Many scoring systems have adjustable lower hubs (see diagram) to allow the adjustment to be made by the operator instead.
For printers, the challenges begin when they integrate a digital print device into their production workflow and find that their existing rotary scoring will not perform with satisfactory results on the toner. In many instances, a combination of creasing and scoring is needed for outputting both offset and digital.
Rotary scoring can be a challenge to the small digital printer because the paper chosen can create problems with finishing. Extreme heat during printing can cause the sheets to curl or become brittle. And once the toner is applied, it sits on the surface of the paper and is easily removed by a rotary scoring wheel. Printing with the grain running in the wrong direction can create even further difficulties in producing professionally finished documents that need to be folded.
To eliminate these problems, a whole range of table-top and fully automated mini-creasers are available. Morgana started the trend in 1998 with the table-top, hand-operated Docucrease. Since then, digital printers have bought creasers in the thousands. Previously, the only way they achieved this quality of crease was to use a letterpress. However, with time-consuming setup and overruns required, this was not profitable, especially in the realm of on-demand printing.
Creasing on these units is done using a creasing rule and matrix action that applies pressure to the paper or card material to create a channel-style crease. This type of scoring is similar to an embossing and weakens the paper fibres.
Unlike a score made with a rotary wheel, the substrate being creased will need to be stopped each time a crease is placed on the sheet, so the process is not as fast. However, a fully automatic creasing will allow multiple creases on a single sheet of paper using just the single-crease matrix. In the world of rotary scoring, you would need to have a scoring wheel for each score. Finally, the appeal of the creaser is broad and has been integrated into other industry sectors such as packaging and greeting cards, in addition to commercial printers.
Pros
- High-speed (sheets do not have to stop to be creased)
- Scoring can be combined with the other finishing applications (folding/gluing)
- Easy adjustment of score width for varying paper thickness
Cons
- Most rotary scoring is on larger commercial equipment and requires setup by skilled operators. Often, machines cannot be set up by digital staff or temps.
- Setup results in more paper waste than creasers.
Pros and cons of creasing
Pros
- Matrix style crease is the highest quality (similar to letterpress)
- Easy setup – most creasers have simple inch inputs and new creasers are particularly easy to set up and adjust
- You can crease across the entire sheet length
Cons
- Lower operating speed
- Must change crease matrix in order to accommodate different crease widths.