Given a scenario, troubleshoot printers with appropriate tools: CompTIA A+ Exam 220-901 sub-objective 4.6
Detailed (and official) description of CompTIA A+ sub-objective 4.6:
4.6 Given a scenario, troubleshoot printers with appropriate tools.
Toner not fused to the paper
Paper not feeding
Garbled characters on paper
Vertical lines on page
Backed up print queue
Low memory errors
Printer will not print
Color prints in wrong print color
Unable to install printer
Printing blank pages
No image on printer display
Overview of printer types and how they function
Troubleshooting printer problems is infinitely easer if you know how they are supposed to function under normal conditions. So we’ll start out by looking at the most common printer found in SOHOs: The inkjet.
A fast efficient printer, the inkjet or bubble jet, can produce picture quality images or plaintext and everything in-between. These printers are capable of duplexing (printing on both sides of the paper) and are capable of creating images from the smallest wallet sized photo to full size legal documents. Interestingly these printers are constantly getting features added. You can find an all-in one printer with full printing capabilities, Fax, Scanner, Bluetooth, Wi-Fi or Gigabit Inc. for under 100 dollars! Slight drawback… Ink costs $99.00. Do your homework before buying! Compare the prices of the consumables versus the cost of the unit.
Alright so how does it work? We’ll examine the device in its configuration as a network printer, shared with everyone without restriction.
You will start by installing the printer on your workstation. Make sure you have the exact make and model number. This is imperative. You may not find the drivers in Windows’ driver list, so if it’s not there go to the manufacturer’s website and get the right one. A generic device driver will give you generic results. Possibly missing features and in the worst case no connection.
A networked printer can stand alone with no other support or it can be shared by a workstation on the network. Realize for either of these first two options to work the printer must be turned on and shared. The sharing element requires the most attention. You must give permission to each user and further which of the printer’s capabilities you want the user to be able to utilize. This is where Groups come in really handy. You could go down user to user and assign the correct capabilities, each option to each user. Or you can assign one set of permissions and capabilities to the PrintOps group and add the users in the PERFORMANCE group to it.
One shot applies 20 solutions! You need to be cognizant of group capabilities and more importantly the effect any changes made to a particular group’s impact on other groups. This could be significant because the PrintOps group is a global Security group.
Alright so we’ll get this A+ sub-objective 4.6 out of the way by addressing specific cases. The objectives are fundamentally just a list of knowledge points that you are responsible for knowing and they don’t have to follow any particular logical order. This will make them seem jumpy because they are! We’ll smooth them out as much as possible while still trying to deliver relevant content.
The Laser Printing Process
The Laser printing process is a continuous 7 step cyclical process in which each step involved is functioning simultaneously. It is a fascinating and efficient process. First, a piece of paper is drawn into the printer while the drum is charged: This is called the Conditioning phase.
The charge is a uniform -600 volt charge being applied to the image drum. The drum is constantly rotating. Next the image to be printed is written onto the drum in what is called exposing or writing. This takes place by discharging the drum by using a focused laser beam turning off and on rapidly while scanning across the drum, discharging some areas and not others. This creates the image on the drum. At this point the image is present but still invisible. Next in the rotation is the toner hopper, where the toner (ink) to be used is drawn onto the drum on the areas that were discharged by the laser beam earlier. The areas we are talking about are very narrow strips and would not look like anything until a few dozen of them were exposed, but that never happens. What does happen is that after the toner is attracted to the drum it is immediately pulled onto the paper by the transfer corona. The transfer corona is positioned so that the paper that will ultimately get the image travels between the drum (now coated with toner) and the corona wire. Pure electrical energy acts as the physical force moving the toner from the imagining drum to the paper. Once the toner is on the paper it needs to be “fixed’ or melted onto the paper. This requires that the paper is heated to a temperature of around 400 degrees. The heat required is determined by the printer, toner and paper manufacturers. It should never be exceeded but must be hot enough to melt the toner. Signs of under heated toner or problems with the fuser (fusing corona) would be streaky, dusty toner. After this the cleaning phase takes place and any residual toner is removed.
When a laser printing cycle begins a single piece of paper is drawn into the printer. A separator pad is used here to ensure that only one sheet of paper is picked up. A failure here could cause paper jams. Other negative outcome are also possible like creased or torn paper.
A Laser printer consists of two main components, the printer and the cartridge. The cartridge contains all of the high wear items. These are the toner, The Photosensitive drum, charging corona, excess toner hopper
Here is a list of the seven steps of laser printing.
- Processing – The digitized image is prepared to be transferred to the photosensitive drum.
- Charging – The imaging drum is charged by the charging corona wire to a uniform voltage of greater than -600 VDC. This voltage repulses all toner on drum.
- Exposing – A laser beam focused on the drum is scanned across the drum discharging all areas of exposure. This drains the charge off of the drum. All points exposed to the laser will now attract toner.
- Developing – Because of the difference in electrical potential Toner is attracted to the areas discharged by the laser and repulsed by the charged areas.
- Transferring – A transfer corona carrying a positive charge positioned permanently beneath the paper path draws the negatively charged from the drum onto the paper.
- Fusing – A fusing roller placed beneath the paper is heated to above 400 degrees which melts the toner powder into the final image.
- Cleaning – Any remaining static voltage on the paper is dissipated and the drum is exposed to an erase lamp to return it to a neutral charge.
The Inkjet process consists of one or more ink cartridges that contain focused nozzles. When not in use these cartridges are positioned in a maintenance station to keep the free from dust. They operate by scanning the print heads across the paper and spraying small focused bubbles of ink onto the paper. Inkjet printers cost less to purchase but have a higher maintenance cost.
Dot Matrix Printers
A dot matrix printer operates on the impact principle. This printer will eject and return a small cluster of individual rods onto a ribbon that is damp with ink and on to the paper, leaving a dot. The result of several passes of an ink head is a readable image made up of these dots. This is the only printer type capable of producing images on multi-sheet carbon paper. They are quite noisy. Special paper is used for these printers that has a series of holes along each side allowing it to be “tractor fed”.
This printer type uses a specially treated paper that is heat sensitive. The print heads are heated to the specified temperature and contact the paper. The chemicals on the paper react to the heated print head leaving a black mark at the point of contact.
Here are some of the common problems you will encounter in the field when supporting printers. Oh, almost forgot! This stuff could very well be on your test too! Here is a breakdown of the process that process.
This first set of problems will be most common on a laser printer.
Steaks on a laser printer will appear a vertical blank areas consistently down the length of the page. There are two causes for this. One is that he toner is not even in the cartridge. This is easily fixed (temporarily) by shaking the cartridge and evenly distributing the toner. You should prepare to replace the cartridge. The second problem could also be fixed by replacing the cartridge. Faded prints indicate a failing charging corona and cartridge replacement is indicated. Ghosting of images on the print is also repaired by replacing the cartridge. In this case it’s important to note that the circumference of the image drum is considerably less that the length of the paper. An imaging drum will rotate completely close to 10 times to print a single page. This makes the cleaning process crucial. Check the erase lamps while you are working. Printing blank pages
Moving on if you have a laser output that is not fused and is sandy or gritty to the touch this indicates a failed fuser. Order and replace.
If you get a memory error when printing, your image is too large (too much data) for the printer’s buffer. This is currently less of a problem, but it still happens. Reduce the size of the image. Reduce the pixel requirement, say from 1200dpi to 600dpi. Reduce the load on the printer until you can diagnose it.
Now if your printer is not printing or printing garbage or printing wrong colors do this:
- Make sure you are connected to the printer.
- Make sure printer is online.
- Make sure the right print drivers are installed.
- Print a test page from workstation to printer.
- Print Self-test page from printer console and compare with machine test.
- Run the printer set-up alignment software.
Here is another set. The print queue is jammed. Pinter will not print:
Do this. Clear all items from queue. This is a personal bit of observation, Person 1 can’t print. They tell person 2 who sends a second job, it doesn’t work so they both try again as news of the problem spreads down the aisle each person tries once or twice and provides “Me Too” comment. Person1 calls helpdesk and tries a print while on the phone. Person 2 sees person 1 on phone, tries print and asks to be included on trouble ticket as do other persons after trying and failing …on and on they had 50 print jobs queued before the help desk could see and clear the queue which by the way only had one document that needed to print.
Moving on. Here are some more issues with the same general solution provided the printer is online and operational: Errors like Access denied, Unable to install printer and errors on local machine can all have their root in permissions. Try accessing the machine the printer is attached to. If the printer is standalone check the Print Operators group make sure you area member with correct permissions. On the printer’s host check your accessibility to the machine. The printer will be visible. Try a test page from there and evaluate the results.
Printer maintenance is not an everyday occurrence. Beside adding ink there is very little required in terms of maintenance. Usually there will be a page counter to give you a good metric on usage and when maintenance would be required.
When you do a Preventive Maintenance on a printer be very aware of the ink, where it is and where it will end up. Be careful. For example you don’t want to ever blow out excess toner from a machine. It should be vacuumed out using a vacuum designed specifically for that purpose. Also use tools designed by the manufacturer to work inside the machine on specialty clamps or screws. Use compressed air in open spaces only. There will be a need to either blow out or vacuum debris out of a printer.
That, my friends, is the last sub-objective of 220-901! Don’t be shy go back and hit anything that didn’t hit home for you. Otherwise, see you in A+ 220-902.
If you are going after the 220-901 exam now, then good luck on the test!