| Troubleshooting |
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| Rails |
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| One of the problems found with the backbone of books is the formation of "rails." As the name suggests, if you look at the backbone of a book with this condition, you will see two raised lines along the backbone resembling rails found on a railroad track. These rails are due to excessive adhesive application and/or a mistimed cover station. This problem will only occur with a thin soft cover such as those found on magazines. |
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| Because of the high speed of magazine production, the hot melt on the spine is still very soft when the cover is applied. If the cover drum is set too tight, the hot melt squeezes slightly to each side of the bookblock. When the side clinchers hit the side of the book, the backbone support must be directly against the spine. If it is slightly out of sync, then the side clinchers will push the excess hot melt to the back of the book. Since the cover is very thin, it will deform and produce two lines of adhesive down the edge of the backbone. This problem is very similar to a "nail head," which is most commonly found in soft cover books with 8 or 10 point covers. Since these heavy cover materials will not distort, the hot melt moves under the side clinchers. To address the problem of rails, be sure the correct amount of hot melt is being applied to the backbone and that the cover drum is not too tight against the book. Also check to see that the book is hanging out of the clamps the correct distance. |
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