Continuous stationery

Continuous stationery (UK) or continuous form paper (US) is paper which is designed for use with dot-matrix and line printers with appropriate paper-feed mechanisms. Other names include fan-fold paper, sprocket-feed paper, burst paper, lineflow (New Zealand), tractor-feed paper, and pin-feed paper. It can be single-ply (usually woodfree uncoated paper) or multi-ply (either with carbon paper between the paper layers, or multiple layers of carbonless copy paper), often described as multipart stationery or forms. Continuous stationery is often used when the final print medium is less critical in terms of the appearance at the edges, and when continuously connected individual sheets are not inconvenient for the application. Individual sheets can be separated at the perforation (leaving a slight serration), and sheets also have edges with punched holes, which also can be removed at the perforation (one typical format).

Most continuous form paper is punched longitudinally along both edges with regularly spaced engagement holes that engage with sprocket wheels or toothed belts on the "tractor" which move the paper through the printer. It is usually perforated transversely with a line of closely spaced holes or slits which form a tear edge that allows it to be torn neatly into separate pages after printing; when fed through the printer the paper is simply a continuous sheet.

After printing the separated sheets can be held in binders by using the sprocket holes when simply required as a record. Alternatively some types of continuous form paper also have longitudinal perforations along each edge inside the engagement holes, allowing the strips with sprocket holes to be torn off the printed page.

The tear perforations may be short slits, which leave noticeable serrations when torn apart, acceptable for many business documents such as invoices or basic data (such as computer code). Where better appearance is necessary the perforations can be much finer, leaving an almost perfectly smooth edge (microperforations, microperf for short).

Continuous form paper of all types remains in production, although largely supplanted with the introduction of fast laser printers with single-sheet feed. Continuous stationery printed on a suitable printer is typically cheaper than laser printing although the output is of lower quality. If an impact printer is used multiple simultaneous copies can be printed on multipart forms. Many laser printers can print on both sides of the paper (duplex printing), which is not possible with continuous stationery.

Standard perforations are 5/32 inch in diameter (3.96875 mm, sometimes called 4 mm) and are spaced at 1⁄2 inch (13 mm) center-to-center. Tear-off horizontal perforations at page top/bottom are exactly in-between standard perforations, at whatever regular interval is used for that particular paper.

When the perforated edges of the paper are manufactured so that they tear off the pages in strips, those strips are known as "perfory."

The highest grade of continuous form paper uses a heavy bond weight similar to typing paper. Perforations are very small and close together, referred to as microperforations or microperf, to allow the sheets to be separated and the sprocket hole strip ("perfory," see "Shape and Form" section) torn off leaving a very smooth edge almost as if guillotine-cut.