To determine the comprehensive quality of a model, the following six factors should be considered: blackness, bottom ash, waste powder rate, fixity and ghost. These factors are interrelated and influence each other. The reasons for these factors are described below.
Blackness: The calculation of blackness value is that the blackness value tester first emits a certain number of intense beams to the figure to be measured, then reflects back to the blackness value tester, calculates the absorbed beams, and then calculates the value through a fixed calculation program. The blackness value of carbon powder is not the higher the printing effect is, the international standard of blackness value (original OEM) is 1.3. In order to meet the different needs of various industries, the average blackness value of ECO powders is generally about 1.4.
Bottom ash: Bottom ash is used to test the blackness value of blanks in printed samples with a blackness tester. In general, the base ash value of the original OEM carbon powder is 0.05-0.06, when it is greater than 0.06, the visual results will feel that the printed sample is a little dirty. Compared with the original OEM, the ash value of ECO carbon powder is approximately 0.05-0.06. The reason of affecting the bottom ash value is mainly related to the conductivity of carbon powder and particle size of carbon powder. The conductivity is strong, and the finer the particle is, the easier the bottom ash will be produced. Each type of printer requires different electrical properties of carbon powder. This is also a reason why we emphasize the specialty of flour. In addition, due to the damage of the photosensitive layer on the surface of the photosensitive drum, the leakage of electricity will also cause the bottom ash.
Waste Powder Ratio: Waste Powder Ratio refers to the proportion of waste powder produced by a certain amount of carbon powder in normal printing. The waste powder rate directly affects the number of sheets printed by a certain amount of carbon powder. The waste powder rate of carbon powder is in the normal range between 5% and 7%.
Resolution: Resolution refers to the point (DPI) that can be printed per inch. The size of carbon powder particles will directly affect the resolution. At present, the resolution of carbon powder mainly includes 300 DPI, 600 DPI and 1200 DPI, while the requirements for carbon powder are quite high for HP1200 and HP4100 printers with 1200 DPI resolution.
Fixation: Fixation is the ability of carbon powder attached to paper surface to penetrate into fibers after melting. Melting point is one of the main factors affecting the fixity of carbon powder. High or low melting point will affect the printing effect of sample.
Ghost: ghost is formed because the unequal charge area formed by the text and graphics on the photosensitive surface remains the charge area which can be formed into latent image after one imaging, so that its latent image can still be seen in the next imaging. The electrical properties of carbon powder directly affect whether the ghost phenomenon is obvious or not.