A blackboard (also known as a Chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulphate or calcium carbonate, known, when used for this purpose, as chalk. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone. Wooden Chalkboard,Wooden Blackboard,Wooden Sandwich Board,Chalkboard Sign Jinan Tri-Tiger Technology Development Co., Ltd , https://www.tigerwoodproduct.com
1. Quality failures caused by defective components of the machine's stamping. When the plate cylinder head, the platen roller head, the drive shaft, the gear, and the important parts associated with the embossing are worn and loose, during the imprinting process The plate roller or the embossing roller will thus have a jumping or sliding phenomenon. Due to the unstable pressure, the contact between the printing plate surface and the paper board is not normal, and the problem of the paste printing plate or the local image imprinting is unclear. Through careful observation and analysis, the exact location of the fault was identified, and appropriate measures were taken to deal with it. The worn and loose parts were repaired to eliminate the fault phenomenon.
2. If the position of the pressure roller is too high or too low due to improper adjustment of the pressure roller, the contact with the corrugated paperboard will be too tight or too loose. There will also be dirty prints, stencils, or local images. The pressure roller is adjusted to a suitable position so that the gap between the pressure roller and the roller is adapted to the thickness of the cardboard to ensure the position of the printing plate to avoid the occurrence of the failure phenomenon.
3, quality problems caused by poor ink roller When the ink roller head loose, ink roller roller body appears bending, deformation or surface damage, it will cause the layout dirty, paste version or local image is not clear. Should find out the reasons, take appropriate measures to deal with, so that the ink roller and the printing plate to maintain uniform and appropriate contact conditions, replace the damaged ink roller, in order to eliminate the phenomenon of failure.
4. Quality failure caused by non-uniform thickness of corrugated board If the surface of the formed corrugated board has a sabotage mark, the paper surface of the recessed area will also have unclear quality defects. , It is easy to make the quality of the text and line layout appear ambiguous. In order to prevent the layout from becoming lumpy, corrugated cardboard should be handled lightly, lightly, and lightly (to control the stacking height) during stacking and handling, and should not be transported by poor production practices such as throwing, squeezing, and pressing.
5, the quality of the plate caused by uneven quality failure When the thickness of the rubber plate is not uniform, the printing plate layout will appear height difference. If the layout is high, it will be easy to paste. Where the layout is low, it is prone to ink incomplete, resulting in unclear imprinting. To avoid this unfavorable situation, it is possible to make the plate into small pieces by means of a sporadic plate-making method. The same plate material should be used for the production, so that its thickness difference is relatively small. If the already prepared rubber plate has a poor thickness, it can be compensated by a multi-adhesive layer on the back of the partially thin plate, so that the entire plate can maintain a substantially uniform thickness, ensuring the printing pressure and the evenness of the printing surface of the plate.
6. Quality failure caused by incorrect color sequence If the layout of the layout is full, the layout of the layout is printed in the first color group. When the corrugated cardboard enters the printing process of the next color group, the printing image of the first color group of the cardboard is used to print the ink. Large amount, slow drying speed, it is very easy to make the imprint transfer cause the layout to be dirty. In order to prevent this problem from occurring, it is advisable to arrange small-size layouts in the first color group, and to arrange large-size layouts in the subsequent color group to avoid imprint migration caused by dirty printing.
A blackboard can simply be a board painted with a dark matte paint (usually black, occasionally dark green).Matte black plastic sign material (known as closed-cell PVC foamboard) is also used to create custom chalkboard art.Blackboards on an A-frame are used by restaurants and bars to advertise daily specials.
A more modern variation consists of a coiled sheet of plastic drawn across two parallel rollers, which can be scrolled to create additional writing space while saving what has been written. The highest grade blackboards are made of a rougher version porcelain enamelled steel (black, green, blue or sometimes other colours). Porcelain is very hard wearing, and blackboards made of porcelain usually last 10–20 years in intensive use.
Lecture theatres may contain a number of blackboards in a grid arrangement.The lecturer then moves boards into reach for writing and then moves them out of reach, allowing a large amount of material to be shown simultaneously.
The chalk marks can be easily wiped off with a damp cloth, a sponge or a special blackboard eraser usually consisting of a block of wood covered by a felt pad. However, chalk marks made on some types of wet blackboard can be difficult to remove. Blackboard manufacturers often advise that a new or newly resurfaced blackboard be completely covered using the side of a stick of chalk and then that chalk brushed off as normal to prepare it for use.
Carton is an outer package of some products, which has a great attraction for consumers. Therefore, the printing quality of carton can not be ignored. Common problems in carton printing mainly include the following points.