Overview
ISO 2784:1974 specifies the sizes of continuous forms used for information processing and the diameter and location of sprocket feed holes. It applies to paper supplied in continuous lengths for automatic data processing (ADP) print‑out of administrative, commercial and technical documents. The standard aligns continuous‑form depths with ISO/R 216 A‑series paper sizes and defines tolerances and layout rules that ensure reliable feeding in pin‑feed and tractor‑style printers.
Key topics and requirements
- Scope: continuous forms for ADP, including dimensions and sprocket hole geometry.
- Depth (vertical) sizes: maps common continuous‑form depths to A‑series equivalents. Examples:
- 76.2 mm (3 in) → near A8/A7
- 152.4 mm (6 in) → A6/A5
- 203.2 mm (8 in) → A5/A4
- 297 mm is A4 (upright); 304.8 mm (12 in) accepted where forms are not to be separated (can be trimmed to A4).
- Width (gross) sizes: recommended gross widths (including sprocket margins) such as 180, 250, 340, 375, 400, 450 mm; trimmed widths correspond to ISO/R 216 where applicable.
- Sprocket feed holes:
- Centre line distance from edge A = 6.0 ± 0.7 mm.
- Hole diameter D = 4.0 ± 0.1 mm (serrated holes: min 4.0 mm, max 4.5 mm). Occasional larger holes up to 6.35 mm permitted with minimum vertical separation of 200 mm.
- Pitch S = 12.7 ± 0.05 mm (0.5 in).
- Tolerances: cumulative centre‑to‑centre tolerance over 254 mm ≤ +0.3 mm; lateral hole deviation C ≤ 0.1 mm; left/right hole alignment E ≤ 0.15 mm; centre lines parallel within 0.15 mm.
- Environmental conditioning: dimensional checks after conditioning per ISO/R 187.
- Printer spacing conventions noted: typical line spacing 4.233 mm (1/6 in), width spacing 2.54 mm (0.1 in), sprocket spacing 12.7 mm (0.5 in).
Applications and users
ISO 2784 is practical for:
- Manufacturers of continuous stationery, multipart forms and preprinted conveyor paper.
- Paper mills and converters producing fan‑fold and roll stock for ADP.
- Line‑printer and dot‑matrix printer OEMs and service engineers ensuring tractor feed compatibility.
- Print shops, data centers and procurement teams specifying reliable feed performance for high‑speed printers.
- Quality control and standards engineers applying tolerances for sprocket hole placement and paper trimming.
Keywords: ISO 2784:1974, continuous forms, sprocket feed holes, paper sizes, ADP forms, A‑series, pin‑feed tractors, fan‑fold stationery.
Related standards
- ISO/R 216 (trimmed sizes of writing paper - A‑series)
- ISO/R 187 (conditioning of paper and board test samples)
