Inside a Laser Printer Facility

Presented below are some of the things that you may not have even imagined about when it comes to the making of a laser printer, as well as about the printer itself.

The Radio Frequency Lab

The printers go through a number of compliance tests before they come out in the market. One of the most important compliance parameters is based on Radio Frequency (RF). These test the RF emitted by the printer and make sure that they are under permissible levels. 

The photograph shown alongside is of the RF Labs where these tests are carried out. Constructed with a cost of about $8 million, the room is plated with ferrite on the walls and conical foams on the top to stop any radio frequencies from coming in from any source, including radio stations, GSM cell sites, or even the simple radio used by the local police. 

Also, the equipment that you see here is pre-certified by a lot of certification authorities. The company, in this case HP, can reduce the time to market the product dramatically by meeting the norms in this facility itself and not go to any certification agency like CE (European Union Certification) at the time of the launch.

Acoustics 

Now what would a printer have to do with acoustics. Actually, loads! Imagine a regular office scenario. You would want to know when the printer starts printing on the other side of the room but you may not want to hear the irritating hiss it makes while pulling paper when you are sitting next to it. This is where the acoustics comes.

A special room lined with foam cones houses the Acoustics Lab. It is a scientifically proven fact that while hearing you listen to 11% of the sound that is directly coming from the source. The rest 89% bounces off walls and other things before it reaches your ears. The foam cones in this room block that 89% of the sound from bouncing off any other object. Thus, if you were to interact with somebody in this room, you would have to really shout.

The black colored device that you see in the middle of all the microphones (in the fig above) used for capturing the sound in the lab is called the 'head'. 

The head is a device made by a company called Head Acoustics, costs half-a-million dollars and is the brain of the whole acoustics lab. It is used to record all sounds emitted by the printer, differentiate them and record them as distinct sounds. These sounds can then be played individually to remove any unwanted noises from the printer.

Psychometric tests

The labs also undertakes various psychometric tests in order to compare the quality of prints that they get from the printer being developed, vis-à-vis other printers in the same category. 

Print cartridges

Most of the technology seen in a laser printer goes inside the cartridge of the printer. And unlike a lot of other contact and non-contact printing technologies, the name of the laser printer is a bit misleading. 

The laser actually strikes the green drum shown alongside in the picture, turning the negative charge on it to the positive charge. The negatively charged toner particles are then attracted towards the positively charged print on the drum. The drum on the other hand transfers these positively charged toner particles on the negatively charged paper rolling below. At the end the toner is fused with the paper using the heated fusion rollers. 

That's why during a paper jam you can see the toner particles sitting on the paper un-fused, which can be easily scraped away by hand.

Toner

Toner is also one of the most important parts of the print process, if not the most important. Since, this is the only thing that is transferred from one container to another before finally fusing with the paper. 

The fusion rollers should be heated to the exact level to make sure that the toner is distributed properly. And this is the reason why most of the times the print quality of the printer decreases with a refilled cartridge.

In the figure you see images taken under a high power microscope. These
display the unfused and fused toner particles from original as well as refilled
color laser cartridges.

Geetaj Channana