The World Of Laser Printers

Applying the principle of xerographic printing, laser printers offer fast printing, high quality text and graphic. They differ from analog photocopying machines where direct scanning of a laser beam on the printer’s photoreceptor produces the image.

Several advantages arise from using the laser printers, and different models of laser printers may have different speed, depending on factors like the graphic intensity for processing.

The latest models of laser printers can print more than 200 single colour pages in one minute. Although the colour laser printers are relatively slower, they can print at more than 100 pages per minute. In addition, the high-speed laser printers can be used for printing mass mailings like utility or credit card bills.

The cost of laser printing depends on the price of the toner and paper, as well as the replacing of the drum, and changing of consumable parts of the printer like the transfer and the fuser assembly. In the long run, laser printers with soft plastic drums can cost more. This becomes apparent when the printer requires drum replacement.

The duplexing model is another feature in the family of laser printers. It allows printing on both sides of a paper without the need to remove the paper. This technology can cut paper cost into half and lessen the filling volumes. In the past, the duplexing technology applied only to high-end laser printers. Now, it is present on many mid-range office laser printers, although it can reduce the printing speed when the paper path length increases.

The dot-matrix and inkjet printers accept the incoming spooled data and print that on paper. This process is slow, which can stop when the printer is waiting for more data. A laser printer cannot work this way because large amounts of data go to the printer continuously. If the printer waits for the data to arrive, gaps and misalignment on the page can occur. Using printer buffer resolves this problem.

With it, the data builds up in the printer’s large buffer, and this data bank accounts for all dots printed on a page. Still, storing dots in the memory before printing limits the laser printers’ capability. Most laser printers cannot print long banners, as no storage memory for that amount of data exists.

The printing comprises seven steps. A Raster Image Processor scans the entire page line by line and stores a bitmap of the page in the raster memory. The drum is then charged negatively and the bitmap is written on the photosensitive drum using a laser beam, whose functionality depends on the bitmap image. The charged toner particles are charged negatively. Charges will repel at locations where the laser has not discharged the drum. As such, printing will not take place. The toner contains a plastic powder that is attracted to the parts where the laser hits. Eventually, the plastic powder is fused at 200 degrees Celsius to bond the ink with the paper.