First, there should be no cracks in the cover body after the folding test. Second, health indicators should comply with the requirements of GB4806.8. Third, the color should be normal, without odor or mildew. The surface is smooth and clean, with uniform texture, no scratches, no dirt, no wrinkles, no peeling, no defects, no holes and no dents; the edges are smooth and regular, the printed patterns and text are uniform in color, the outline is clear and complete, and the position is accurate. The indentation position is accurate and clear, with no hidden lines or fried lines, and the cardboard does not crack at the creases when folded and formed. The bonding is firm, the glue does not open, and there are no glue stains on the surface.