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Which type of printer operates most like a photocopy machine
In a standard thermal inkjet printer, ink is fed from the cartridge into thousands of minute reservoirs in the print head and then quickly heated, causing the ink to form a bubble. This bubble then shoots the little droplets through a nozzle onto the paper. These dots produce the lines, letters, and subtle color gradations that we perceive in a final print.
Printers and photocopiers employ static electricity to print digitally. They were conceived at Xerox Parc in the 1970s and were initially offered for home and business markets by firms like Xerox, Canon, Hewlett – Packard, and Apple in the following years. Laser printers are now extensively used worldwide, with quality and speed improvements as the cost of the technology has lowered.
Laser printers are similar to photocopiers in that they employ the same fundamental technology.
Static electricity causes ink particles to attach to the drum, and the ink is subsequently transferred to the paper and fused to its surface using heat. A laser printer operates essentially identically to a photocopier, with one important exception: there is no original page to replicate. Therefore, the laser must recreate it using digital data and code.
By repeatedly sending a laser beam back and forth over a negatively charged 'drum' (a light-sensitive spinning cylinder) to define a positively charged print arrangement, laser machines may generate higher-quality prints. The drum will then gather and transport electrically charged toner (powdered ink) to the print medium. The toner is then fused to the paper when heated.
Use of a laser printer as a photocopier:
Copiers and laser printers have many similarities. The primary distinction is in how an image is produced on a photosensitive drum:
- A copier focuses an image of the original (a strip at a time, is scanned in most current low to medium performance copiers) onto the drum using a powerful light and lens. The reduction or magnification is varied by adjusting the lens-to-original and lens-to-drum distances.
- A laser printer scans one line at a time on the drum using a low-power, finely focused laser beam. Modern laser printers employ infrared solid-state laser diode, similar to those used in CD players and optical disc drives, but earlier models use helium-neon lasers. The digital picture, which modulates the laser beam, is created from a bit map stored in the printer's memory.
- A high-speed motor spins a multifaceted deflection mirror to obtain the X-axis, and the paper moves to get the Y-axis.
- LED printers are similar to laser printers in that they employ a wide array of LEDs as the image source.
- In its printing mechanism, plain paper fax machines employ comparable techniques.
Aside from that, copiers and laser printers are almost identical, with the exception that copiers use a positive process (dark regions in the original result in markings on the paper) while laser printers generally employ a negative process (a spot of light resulting in a dark mark on the page).
The most advanced machines are now scanner-laser printer combos with buffer memory. They allow many copies to be created without rescanning the original, more flexible sorting and collating digital scaling and rotation, and other capabilities not achievable with conventional copiers.
The laser printer or copier's heart is the photosensitive drum. It may be a separate replacement unit in larger machinery. It is a throw-away portion of the 'toner cartridge' in most laser printers and smaller copiers (or maybe recycled).
The drum is covered with a photosensitive substance. It has a very high resistance to light. When lighted, its resistance lowers to a low value.
All of the following happens in real-time as the drum rotates. It's worth noting that the actual photosensitive drum in most copiers and laser printers has a significantly smaller circle than the length of the printed page. As a result, only a portion fits at any given time, and charging, exposure, transfer to paper, cleaning, and erasing are all ongoing processes:
- A series of corona wires next to the drum charges the surface to a high positive voltage (usually 5 to 6 kV).
Copiers and laser printers have different exposure processes:
- A slice of the original is focused onto the drum for copiers. A quartz light and strip mirror travel along the original strip turning mirror as the drum spins, and a second strip turning mirror moves at half the speed. As a result, the complete original picture is 'peeled' onto the revolving disc.
- For laser printers, the negative image of the page is read out and scanned onto the drum one line (i.e., 1/300th or 1/600th of an inch) at a time from the printer's buffer memory.
- When light strikes the surface of the drum, its resistance reduces considerably, and the charge in these regions dissipates.
At this time, patches of electrostatic charge on the drum represent a swath of the image of your final copied or printed page. It is a 'latent' picture that has to be 'developed.'
The latent picture revolves past the 'developer unit,' which holds a combination of developer and toner while the drum rolls. Most of the time, the developer is not used up throughout the printing process, but some are lost and may need to be replaced from time to time.
- A developer is a substance composed of powdered iron or another powder attracted by a magnet.
- Toner is the ink. It is made up of tiny powdered thermoplastic particles. The picture is practically melted onto the paper and is fixed in the fuser.
The developer material may be separate or integrated with the toner.
A magnet in the developer unit causes the developer and imprisoned toner to stick out by following the lines of force off of its long N-S pole pieces. It creates a toner and developer brush that comes into contact with the drum as it rotates with its latent image. The developing material brush is C-shaped, and the toner particles are conveyed in the C-shape (the back of the 'C' is against the drum).
Here are the differences in the development methods of copiers and laser printers:
- Toner is pulled to the unexposed (dark areas of the original) regions of the drum in copiers, resulting in a positive picture on the paper.
- Toner is pulled to the exposed (where the laser beam was switched on) regions of the drum in laser printers, resulting in a negative picture on the paper.
The drum keeps rotating and comes into touch with the paper.
Another corona, the 'transfer corona,' is visible beneath the paper. Another high voltage is provided to the back of the page. It pulls the toner from the drum to the page.
Depending on the machine's manufacturer, you may or may not have a third corona, the separation corona. It is required to separate the paper from the drum while preserving the toner on the page (the separation corona is typically 4 or 5 kV AC). The separation corona is frequently equipped with guides to prevent the paper from 'dipping' too deep into the corona shell.
The paper is then carried to the fuser, which uses heat (to soften the toner particles) and pressure to 'fix' the toner to the page(to embed them in the paper fiber). Parts of the fuser also protect the paper from adhering to the hot rollers. The heat within the anti-stick (Teflon coated) fuser roller is provided by a thermostatically regulated quartz tube light.
Print or the copy of the page:
Finally, your printed page or copy is complete!
However, we are not finished since there is still some toner on the drum (it is not feasible to remove all of it electrically). Therefore, there is a rubber or plastic blade that scrapes on the drum. The 'drum blade' scrapes the toner off the drum, and the recovery blade' catches it to prevent it from sliding back into the machine. A 'used toner auger' transfers the used toner (which is now altered both physically and electrically and is also polluted with paper dust) since it might ultimately harm the developer unit, cleaning blades, fuser sections, and other portions of the mechanism.
Still, some residual charge from the earlier exposure procedure, even though all toner gets scraped from the drum. Because the static charge cannot be scraped off the drum, the cleaned drum is now fully exposed to a bright light to discharge the drum surface and ready for a new charge, which follows immediately after the discharge lamps.
That is the fundamental procedure. Many variants are conceivable, and some may change depending on the machine and manufacturer.
Many of these components are changed with the cartridge when a (disposable) toner cartridge is used. Components are the drum, toner itself and developer (usually mixed into a single powder), developer magnet (very neat! ), cleaning blades, and part of the corona wires.
Photocopying on Laser Printer:
Press the Lighter/Darker button, then use the arrow buttons to adjust the amount of darkness, and then press OK. Press the Number of Copies button, then input the number of copies using the keypad or arrow buttons. To begin the copy operation, press the Start Copy button.
Thus, we can see that a laser printer can be used for photocopying purposes.