0 Laser Printers

Introduction:
             Laser printers are the most advanced form of the printers. They gave a better image and text of high quality on the plain pages. Laser printers are considered as the most important form of the printers.We the passage of the time man requires best and the better facilities for him for the ease of his life so the scientists are trying to do so. So the printers were invented for the ease of the man and now they are going to be modified every day by day. Therefor there are a lot of forms of the printers (e.g laser printers) and they are of a lot of types.
Invention Of Laser Printers:

      In 1969 a scientist Gary Starkweather  invented the first Laser printer. In 1971 the these printers were improved and then the inventor starkweather used the spinning drum(attached with a laser) of eight mirrored sides in the laser printers. 
In 1975 the first commercial implementation of the laser printers was IBM model 3800 used for the very high quality of the documents and such entities. The size of each of these printers was about the size of a single room that each was fitted alone in a room and many of those models of the laser printers are still used by some of the companies and factories etc. In 1981 the first laser printer was designed for the office but it was so worthy. The price of each printer was $17,000. So we can say that only a few business men bought the laser printers in those days. 
In 1984 the first laser printer (HP LaserJet 8ppm) was designed for the mass market. These printers are fast, hd printing and very much advanced form of the printers. You can't get such qualities in any other printer. In the 1984 HP laser Jet was sold at $3500 but in 2008 the price monochrome laser printer has fallen to the $75. 
How Does Laser Printers Process(work):
There are involved seven steps in the process of the laser printers through which they work.
1.Raster Image Processing:

•  This is the first step of laser printers process. 
• The horizontal strip means dotted lines drawn by the laser printers are known as the Raster Lines and in some other words they are also known as the scan lines.
•  So when many raster lines are aligned or arranged by the laser printers on the paper so a figure of the image which is to print is formed this process is called raster process.

Example: 
          If you ever saw the process of the cloth making through the thread then you can understand it easily that how does many layers of the threads are kept aligned and then the designed cloths are formed. We can say that on the same principle the Laser printers draw the raster lines then make a image through them and the process is called raster process(RIP).

• The RIP gets the description of the final page in the raster memory and make a bitmap of it. 
• For perfect image or graphical output use a page description language, nearly one megabyte of memory is used  to save an entire monochromatic language letter/A4 sized page of dots at 300 dpi. 
• Each of the square of the dots contain 84 sq/in × 90,000 dots

2. Charging: .

• Second step of laser printer's process.
• In the former laser printers a wire namely corona was placed parallel to the drum and in the most advanced printers a primary charge roller is attaches an electrostatic charge on to the photoreceptor a revolving photosensitive drum or belt which is able to capture the electrostatic charge on its surface while it is in dark.
• Usually in the laser printers an AC bias is given to the primary charge roller to remove the effect of the colors of the last printed image.
•  On the other hand a DC bias is also given to the laser printer's drum to to confirm a uniform negative potential.

3. Exposing:                   

•   This is a third step of the laser printers' process. 
• On the rotating polygonal cylinder  (present in the laser printers)the laser is attached in such a way that it emits the laser beams which fall on the photoreceptor after passing through the a specified system of the lenses and mirrors. 
• During this process the cylinder rotates continuously. 
• In the memory the raster data turns the laser on and off so the dots are formed on the cylinder. 
• The laser beam neutralizes a narrow beam over the large distances and also neutralizes charge on the black part of the image leaving a static electric negative image on the photoreceptor of the laser printers. 

4.Developing: 

•  This is fourth step of laser printers process.The latent image is given to the toner dry plastic powder gets mix to the carbon black or coloring agent.
• Then the charged toner particles are given the negative charge and they are automatically attracted towards the latent image of the photoreceptor and attach to the points on which the laser is touched.
• Because both of the toner and drum have the same charge so they will not touch the drum.

5.Transferring:

• Third step of laser printers' process.
•   The photoreceptors are rolled over the paper so the image of the given texture to the receptor is printed to the paper this is an important part of laser printers' process.

6:Fusing:

• This is the sixth step of the laser printers' process.
• The printed image is passed to a roller. 
• Here the heat and the pressure is provided to the image to press the image on the paper.
• There is used a fuser roller.
• The heat is given properly so the print on the paper is given properly.

• Heat is provided up to 200 Celsius.

7:Cleaning:

• Seventh step of laser printers' process.
• The toner on the receptor may be left if any kind of the problem such paper jam takes place.
• But apart from the occurring the problem the process of cleaning may restart and then the toner is removed from the photoreceptor. 

So I think it so that I have told you about some specific points on the Laser printers.I tried my best to explain laser printers topic.                              Thanks! for reading my topic.