Printers: CompTIA A+ 220-1001

Part-1 of Laser Imaging Printer Process

Part 1: PROCESSING So step 1 is processing. And during this phase, the image itself is converted to a raster image, again, by the raster image processor. And it's stored in the printer's memory.

Part-2 of Laser Imaging Printer Process

Part 2: CHARGING The charging phase, then, is where we see that negative voltage applied to the drum itself, using the primary charge roller, or what's known as the corona wire. And typically, again, this is between -500 and -1,000 volts, most commonly around -600 volts. But again, this charges the entire drum as it rotates around.

Part-3 of Laser Imaging Printer Process

Part 3: EXPOSING The exposing phase, then, is where the laser actually shines on the drum, and because it's a photosensitive drum, as mentioned previously, this drains off the charge wherever the laser strikes it.

Part-4 of Laser Imaging Printer Process

Part 4: DEVELOPING Then developing is the process of the toner being applied to the drum. Again, the toner has the same negative charge, so negative charges repel each other. But since the laser has drained off that charge in specific areas, the toner is attracted to those areas.

Part-5 of Laser Imaging Printer Process

Part 5: TRANSFERRING Then, during transfer, we see the toner being transferred from the imaging drum onto the paper itself.

Part-6 of Laser Imaging Printer Process

Part 6: FUSING And then fusing is where we see the fusing roller applying heat and pressure to quite literally melt the toner onto the paper.

Part-7 of Laser Imaging Printer Process

Part 7: CLEANING And then finally, the cleaning process is where an actual blade, very much like a wiper blade on a windshield, scrapes off any residual toner. And you may also see in some models a recharge, whereby there's a lamp that shines on the drum to reset the entire charge to neutral so that it's ready to go for the next job.

So the toner is attracted to the areas where there is no charge, and essentially this is how the image is produced.

But the idea is the fact that, because there is an electric charge on that drum, toner is attracted to it. But it is only applied to the drum where the laser strikes it. (here we see the imaging drum and corona wire, and the laser) So, again, what happens is that the entire drum is charged by the corona wire. Since it's photosensitive, wherever the laser strikes it, it drains off the charge. Now the toner on this toner-coated roller also has a negative charge. So negative charges will repel each other. The toner will not come off the roller to areas of the drum that still have a charge. But where the laser strikes it, the charge is drained off. So the toner is attracted to the areas where there is no charge, and essentially this is how the image is produced.

Laser Printer: (Fuser Assembly and Pick-Up Rollers)

So then the fuser assembly and the pick-up rollers are involved with, of course, moving the paper through and ensuring that the toner is quite literally melted onto the paper. The fuser assembly gets very hot and it quite literally melts the toner onto the paper. And the pick-up rollers are responsible for, quite literally, picking the paper up and feeding it through the printer.

Laser Priner (Transfer Belt & Transfer Roller)

So then the transfer belt and transfer roller are responsible for the toner being transferred to the paper. They apply an opposite charge, so it attracts the toner to the paper itself. Now a transfer roller is typically what you're going to find in a black and white laser printer. A transfer belt is typically what you would find in a color laser printer because it applies different colors to different areas of the belt. But that's not necessary with just black and white, so it only needs a roller.

Laser Printer (Imaging Drum & Corona Wire)

imaging drum: With the laser printer itself, the imaging drum really is at the heart of the process. This is a rotating round cylinder that is photosensitive, so images are written onto the drum by shining that focused laser light onto it. Corona Wire: And the primary charge roller, or what's known as the corona wire, is responsible for applying a negative voltage to that drum. And it's typically between negative -500 and 1,000 volts, but most commonly around negative 600. But the idea is the fact that, because there is an electric charge on that drum, toner is attracted to it. But it is only applied to the drum where the laser strikes it.