Know all About Here About Printer Drum
The work of laser printers is based on the transfer of dye powder (toner) by an electron method onto the surface of a drum, which forms an image on paper. As a result, the drum unit is the main part of a photocopier (here the laser is replaced by special LED units) or a laser printer. The drum of a printer is made in the form of a 21 cm long hollow aluminum cylinder, which corresponds to the size of the A4 paper. In some cases its length can reach ten centimeters. A multilayer coating is applied to the surface of the aluminum cylinder.
This is the base layer and the transfer charge layer of the outer coating. Added to this is the cylinder body, the aluminum tube that serves as a conductive layer. The upper layer consists of a photosensitive substance based on selenium (an element that is practically not used recently), amorphous silicon or organic compounds, whose composition is a trade secret. The photocell rotates with the help of gears mounted on the ends of the cylinder.
The drum is placed in the printing device in two ways: directly in the machine or in a single unit with a toner bottle. Separate devices for photoreceptors and toner cartridges are used in various expensive models of printing devices, which enable:
- Set the duration of the printed sheets in tens of thousands of copies (in a block with a toner cartridge, the maximum number of copies is 10 thousand)
- Change a detail without replacing other parts of the printer or copier.
The drum unit includes a small track and a used dust container. The connection in a single unit of a tube with a toner and the blocking of the drum, on the one hand, reduces the cost of the node, on the other it reduces its duration. The photographic drum thus withstands up to 4 recharges, a quantity of 2-10 thousand copies, after which it must be changed.
Principle of operation
The printing process begins with the creation of a static field on the surface of the drum. The role of the electrostatic voltage of the conductor is performed in the aluminum housing. The field can be both positive and negative. The same charge should be distributed independently on the surface of the drum, so as not to be attracted to the entire surface of the shaft.
The laser highlights, in a mirror image, the text or image that must be transferred to the paper; this image is also reflected on the drum. Under the action of light, the photosensitive layer changes its charge in reverse; after this the coloring powder is attracted. The drum, rolling on the paper, transfers the toner onto it: generally it is an action that takes place in a very short time, a thousandth of a second. Under the influence of high temperatures from a special stove included in the printer, the drum interacts quickly with the pores of the paper. The result is the desired image.
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The manufacturers of some printers – such as Samsung, Xerox or Brother – use a non-magnetic dye powder. An additional magnetic shaft is used to transfer it to the surface of the photoreceptor.
The quality of the paper must meet the criteria established by the instruction manual for printing the devices: the paper with poorly cut edges leaves scratches on the surface of the drum, which leads to a decrease in print quality and, with an increase of their number, to the replacement of the drum itself. The sheets that are dense or wet with moisture quickly consume the photosensitive layer. The coated paper leaves dust on the surface of the photoreceptor, which also negatively affects printer performance. Many manufacturers advise against double-sided printing. Therefore, draft prints on used paper should be avoided.
Printing in A5 format on A4 paper shortens the life of the drum cartridge by two times. The correct solution is to print 2 sheets of A5 size on a standard sheet of paper, which is then cut or folded. Significant temperature drops and high humidity in the room where the printing equipment is installed also affect the duration of his work as a whole. So, if you want the drum to live longer, you need to pay attention to those factors that seem unimportant at first glance, like the temperature and humidity of the room.
When should I change the printer drum?
The photovoltaic coating of the upper paint is damaged by wear on the photovoltaic coating if the black dots appear at the same distance from each other, most often along the edges of the sheet. The rate of drum wear depends directly on the quality of the paper used for printing and on countless other factors, including those mentioned above.
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