Double signature fed from one station
High severitySymptoms
Thicker blocks; double mark in the spine staircase; stitcher jams
Probable causes
- Station separation badly set for the thickness
- air-swollen or badly folded signatures
- worn suckers/grippers
The Print Guy · 2026-10-05
Other problems in this category
Gathering/Stitching/Gluing · TPG-237
Missing, duplicated or out-of-order signature
Books with skipped or duplicated pages; client complaints
Gathering/Stitching/Gluing · TPG-239
Signature not opening at the center on the saddle
Signatures dropping closed or off-center onto the chain; stitching off the fold
Gathering/Stitching/Gluing · TPG-240
Loose, deformed or badly closed staples
Staples not holding, raised legs scratching or cutting, magazine shedding pages
Gathering/Stitching/Gluing · TPG-242
Uncompensated creep
Inner margins 'growing' toward the center signature; text or folios trimmed off
Gathering/Stitching/Gluing · TPG-245
Side glue insufficient or excessive
Insufficient: cover swinging open like a door. Excessive: visible glue staining first/last page
Gathering/Stitching/Gluing · TPG-241
Staple tearing the spine
Paper tearing at the staple; booklets loosening in use