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Showing posts with label Printer. Show all posts
Showing posts with label Printer. Show all posts

Laser Printers

06:29 | Labels:


How Laser Printers work

Laser printers, which are one of the most popular printers used today. It uses the technology implemented in photocopiers to print the pages. Laser invented way back in 1969 at Xerox.

The key component of the laser printer is the revolving drum which is also called photoreceptor. This selenium coated drum is made of the highly photoconductive material. Initially is given the total positive charge and rolled in toner. After this, the toner is transferred to the page, fused with heat and pressure and it is then that the image is printed on the page.

After printing the page is passed on to the pair of heated rollers, this is done to melt the loose toner powder on the paper and henceforth the fuser rolls the paper and the paper comes out on the tray.

The basic difference between the inkjet and the laser printer is that inkjet uses the wet ink to print the characters on a page whereas laser printer uses the dry powdered substance, so the print of inkjet printer is vulnerable to smudging but this is not the case with the print of laser printer.

More importantly the cost per page in the laser printer is quite less as compared to the inkjet printer. So if a user has loads of pages to print daily and of good quality it would be advisable for him/her to use the laser printer. Often we can get the inkjet printer at a relatively cheaper price than laser printer but the cost of re-filling the cartridge overshoots the actual cost of an inkjet printer. So, the costs of operating an inkjet printer are much high after its purchase.

Resolution or the quality of the laser printer depends on the DPI or the Dots Inch printed on the paper. Dpi in laser printer can vary from 300 dpi in low end models to 1200 in the top end models. Colored laser printers can be eight to ten times more expensive than the monochrome laser printers. 

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Inkjet Printers

06:29 | Labels:


How Inkjet Printers works

Inkjet printers are the most commonly used printers today. They operate by spraying droplets of ink on the paper which form the characters or the illustrations on the paper. Inkjet printers became popular in mid 1990’s and since then have replaced dot matrix printers due to their better print quality and faster print rate.

Most inkjet printers now have USB ( Universal Serial Bus) port to connect to the PC and laptop but many inkjet printers still use parallel ports to connect to the CPU.

Components/Architecture

The print head in the Inkjet printers consists of the nozzles or small holes through which the ink is sprayed on the paper. There are two different method/technologies, which are used by inkjet printer: thermal bubble and print piezoelectric.

There are separate cartridges used by the inkjet printers for black and color printing. Some cartridges itself contain the print heads.

While printing, the cartridge moves horizontally back and forth on the paper and the stepper motor facilitates this movement.

There is a stabilizer attached to the motor to control its movement There is also a belt in side the printer which attaches the motor and the print head together.

While printing, we keep the paper on the feeder tray and the paper is pulled in by the rollers and then dispensed out after the printing.

Types of Inkjet Printer

In inkjet printers, which employ thermal method to print, there is a heater which when receives the current is heated and then drives the ink out of the nozzle. The ink bubble formed due to this tension forces more ink out of the cartridge.

In piezoelectric based printers, piezoelectric material, crystals attached to the nozzles force the ink out which then print the pattern on the paper. This method has been patented by Epson. Piezoelectric based inkjet printers give better quality of images.

Though inkjet printers give better quality of printing but, if one needs to print many documents daily then the cost of printing may escalate due to limited number of pages which each cartridge can print. Depending upon the manufacturer, cartridge may print 300-600 pages varying on the usage and type. So, its up to a user which kind of printer does he opts for. Although ink jet printers have low initial costs, their print rate per page is high.

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Matrix Printers

06:28 | Labels:


How Dot Matrix Printers work

Dot Matrix printers also called impact printers print the characters by striking the combinations of pins on the print ribbon; the ribbon in turn strikes the paper which is placed against the drum and at the point of the impact characters gets printed on the paper.

Dot matrix printers were extensively used during 1970’s and 1980’s, though these printers created lot of noise and were slow to print but they were extremely popular on account of less cost price per print page. Gradually dot matrix printers were replaced in most places by inkjet printers which were more efficient than the former due to less noise, fast printing and more importantly better print quality. But still the dot matrix printers are brought to use at many places where the more pages are needed to print and quality is not much of a consideration e.g. like cash registers or in places like banks or offices where large amount of data logs are to printed.

Since the characters are printed when the pins strike the ribbon, the number of pins can be said to be directly proportional to the print quality. Earlier dot matrix printers used to have nine pins but the print quality wasn’t that great, then the companies started manufacturing printers with 18 or 24 print heads. 24 head printer used to print quickly and better quality and graphics. Some of these printers even had magnet print heads which were faster and with better quality. The speed of dot matrix printers can vary from 50 to 500 cps.

Though some companies like Apple Inc. introduced colored dot matrix printers but they never really gained wide spread acceptance because of poor print quality. In colored dot matrix printers there are three or more ribbons of different colors and when we type anything the combination is printed by aligning these ribbons and generating the desired pattern. But the colored ribbons sometimes used to overlap black colored ribbons and one would get distorted pictures or characters.

Dot matrix printers like any other impact printer can be used to print carbon copies. These printers are less common today and as mentioned have been more or less replaced by inkjet and laser printers. The latter kinds of printers especially give better print quality and at a much faster rate.

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