The work of the matrix (needle) printer, like any mechanical device, is always accompanied by noise, to reduce the level of which various technical solutions are applied. Some printers have a so-called silent mode (Quiet Mode), but it reduces the printing speed twice.
In inkjet printers, only the engine that controls the head of the printer emits a slight buzz. The noise level is about 40 dB, which is 15 dB less than for matrix printers.
Laser printers have about the same noise level.
The indicator for evaluating the print quality of the printer is the resolution or resolution, estimated by the number of dots printed on one inch (dots per inch - dpi).
The resolution of a matrix printer is determined by a number of factors:
• the diameter of the needles, their number and location in the matrix, the size of the matrix and the quality of the ribbon;
• The print speed, which is limited by the maximum frequency of the needles. As the speed increases, smearing points;
• The amount of shift of the print head (possibly paper) to the left-right, up-down, which increases the number of passes along the printing line.
Therefore, dot-matrix printers are capable of working in modes with different resolutions - from small resolution for quick drafting to high (NLQ - Near Line Quality, quality close to smooth typewriters), which is 360x. 360 dpi.
The resolution inkjet printer (like the matrix) is determined by the diameter of the nozzles, their quantity and location in the recording head. Due to the possibility of using a large number of nozzles in inkjet printers, a resolution close to the resolution of laser printers is achieved. Significant importance is the quality and thickness of paper. To quickly dry ink, use paper heating. The resolution of inkjet printers when printing graphics is from 300 x 300 to 720 × 720 dpi.
For laser printers, the horizontal resolution is determined by the number of dots in one line and limited precision aiming of a laser beam by a deflection mirror, and vertical resolution corresponds to a drum step, so many models of printers have a resolution unbalanced. For example, with a laser beam precision of 1/1200 in. And a 1/600 inch drum step, the resolution is 1200 × 600 dpi. Laser printers have the highest resolution.
For matrix or inkjet printers, the final thickness of the needles or nozzles causes the uneven placement of individual points. As a result, when printing inclined lines, there is a so-called stair effect, which manifests itself when reproducing graphic images and large text. The problem for laser printers was solved for the first time by Hewlett-Packard company, using RET-technology (Resolution Enhancement Technology - technology of resolution increase), which improves the quality of text output, bar and halftone images. The essence of RET-technology is that with the help of a special chip the intensity of the laser beam is controlled, due to which different levels of charge are created on the surface of the drum. The charge of each point of the raster is varied by five gradations, which ensure the elimination of the staircase effect.