Several reasons for the rupture of the book spine incision？

The Reasons and Solutions for the Outbreak of Books and Magazines on the Backbone

There are various reasons that can cause the spine of books and magazines to become violent, usually including the following six situations.

1. Reasons for the direction of the silk threads on the cover paper

In theory, if the direction of the paper thread is perpendicular to the spine of the book, it seems more conducive to solving the problem of "sharp edges" in cutting the spine of books and periodicals. However, it can also cause the problem of book back wrinkles. To weigh the pros and cons, printing companies usually choose the direction of the cover and book core thread to be consistent with the direction of the book back.

But for some thick covers with poor texture, there will be layer cracking and tearing phenomena in both horizontal and straight thread directions. In this case, only cover film can be used to solve it, which increases the production cost.

2. The adhesive on this side of the installation is too thick

This is an issue with the captain‘s operation. If the adhesive on both sides of the book is too thick, it will cause the spine to be too high, resulting in a "bulge" at the back of the book. In this case, it is necessary to adjust the thickness of the adhesive on both sides correctly.

3. The groove cutter is worn or improperly adjusted

When the grooving knife is not sharp after wear, the grooving shear block is worn too much, and the gap between the grooving knife and the grooving shear block is too large, it will form groove deformation and the surrounding area will be rough and not smooth, causing the back of the book to be wide and the spine of the book and journal to be "exposed". At this point, the groove cutter and groove cutting block should be replaced in a timely manner, and the gap between the groove cutter and groove cutting block should be adjusted.

4. Improper grinding angle of the cutting blade

The cutting blade has a small grinding angle, which has the advantages of being sharp and not easy to "cut", but the disadvantage is that it is not durable to cut. On the contrary, the cutting blade with a large grinding angle has the advantage of being durable, but the disadvantage is that it is prone to "bursting". The most suitable grinding angle for general cutting knives is between 19 ° and 25 °. At the same time, it should be noted that a small angle should be used for initial grinding and a slightly larger angle should be used for chamfering. But for blades of different materials, there should be differences in blade grinding. We suggest that the initial grinding angle of high-speed tool steel knives is 19 °, and the precision grinding chamfer is 21 °; The initial grinding angle of the hard alloy steel blade is 21 °, and the precision grinding chamfer is 25 °, which takes into account both sharpness and cutting resistance factors.

5. Environmental temperature and humidity reasons

The humidity of the post press production environment also affects the bursting of the cover after indentation, causing the phenomenon of "head popping". Especially in winter, the environment is extremely dry, the moisture content of the cover is low, and it is very easy to burst after indentation. Figure 3 shows the burst line phenomenon that occurs on the cover during winter indentation. Therefore, when the humidity in the post press work environment is too low, it is necessary to turn on the humidifier and balance the humidity in the production work environment in a timely manner. The ideal moisture content of paper is usually around 6%, the ambient temperature should be controlled at around 20 ℃, and the relative humidity should be controlled at around 60%. In addition, when using indentation steel wire, using light pressing can also improve the phenomenon of bursting and bursting of the indentation wire.

6. Reasons for the looseness and noise of book posts

This situation is the most common drawback, mainly due to the lack of creases on the back of the book or the lack of compression and compaction of the book, resulting in the book core not being completely emptied, forming a loose pool of book core. The accumulated thickness at the folding point of the book post is superimposed on the back of the book, forming a high thickness difference at the back of the book, which is the main reason for "head popping". At this point, it is necessary to install a spine knife to solve the problem, which is also an effective method in this article to install a spine knife to solve the problem of "head popping" in the back incision.

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