Your local independent Printer Repair specialist West Sussex & Surrey

01293 537827



Printer Repair - Sales - Total_Costof Ownership - FAQ
All our staff are CRB checked and carry ID



Frequently Asked Questions

Drum unit replacement.

The drum unit contains Developer, Drum & Charge rollers. Developer is rugby ball shaped carbon granules of a predetermined size. Toner is added to the developer mix from the toner cartridge, toner being negatively charged it is attracted to the positively charged Developer granules.

Magnetic Brush / Development Roller

The developer and toner mix is agitated within the drum unit where the developer being ferrite based it is attracted to the Magnetic Development Roller, the Doctor Blade / Developer blade limits the amount of Developer on the Development Roller.

Laser printer toner developer transfer systemMonitoring the Toner / Developer mix level

During this stage of the process the machine senses whether there is enough toner in the mix and adds more if necessary. This is done by inducing a charge in a coil of wire, when a magnetic developer is rubbed against a coil it induces a electrical charge in the coil. If there was no toner in the developer mix then the developer granules would be closely packed together on the development roller and would induce a high charge. When toner particles are present in the mix the developer granules are forced apart and a lower charge is developed, this is how the machine maintains the correct toner levels. As toner is transferred to the drum to form the image the toner sensor voltage increases and the toner motor turns on to add more toner until the sensor reaches its optimal value.


Why do I need to change it?

During the life of a drum unit the constant agitation of the developer wears the granules turning them from diamond shapes to rugby ball shapes. This then creates an air gap between the mix and the toner sensor, because there is a gap a lower charged is induced in the toner sensor coil which the machine interprets as a high toner concentration therefore toner is not replenished as required, the result is wishy washy solids, this effect will intensify as wear continues. You will also find that the machine starts to soot up with spilt toner that has not been transferred to the drum properly.

OPC Drum Surface

The photo-conductor drum is a light sensitive coating on the drum surface, this surface gradually gets worn by paper passing under it, as it wears its sensitivity reduces and so it attracts less toner, this compounds the developer problem.

New drum is just like a sharp pencil, sharp lines, strong colours.

Old drum is just like a blunt pencil, fuzzy lines, weak colours.

Fuser Unit Laser printers fix the toner onto the paper using heat and pressure (Fuser Unit). The system employs two rollers the top roller (heat roller) is a hollow aluminium roller coated in Teflon (the roller is coated in Teflon to stop toner sticking to it). Through the centre of the heat roller is a tungsten halogen heater lamp (similar to a cooker) the lamp heats the surface of the heat roller to approx 200 degrees. The fuser unit monitors the temperature via a thermistor and turns on and off the heater lamp. The lower roller (Pressure Roller) is rubber and is constantly pressing against the heat roller.

A bit about paper Laser printer / copier paper has a 5% moisture content, this is why the wrapper is coated in wax to stop moisture penetrating, as soon as a ream of paper is opened it will absorb moisture until equals the atmosphere (which can be 25 30%)

Photocopying or printing on paper with a high moisture content The hot roller runs at a slightly higher temperature then the lower pressure roller, so the top side of the paper nearest the heater roller will get hotter causing it to curl due to shrinkage. Also the moisture absorption is not constant so shrinkage occurs at different rates causing a corrugated effect. This is not cause a problem on single sided copies. But if you try and print or copy double sided,  you will have several issues,  jamming, creasing and print rubbing off.

         Jamming because the paper does not enter the fuser unit straight.

         Creasing because the pressure roller will try to crush the curled corrugated paper flat.

        Print Rubbing Off Print will rub off because the high moisture content has stopped the paper reaching 179 degrees, the fusing temperature of toner.

Example I was asked to repair a copier that appeared to be reducing an image on the second side. The image had a square border 1cm from the edge of the paper, when you held the double sided image up to the light it was obvious that the second side was 3mm smaller then the first side. A lot of head scratching and checking was done. Finally I held a copied sheet up against an un copied sheet of A3 paper the copied sheet had shrunk by 3mm during the copy process. Because toner is laid onto the paper prior to fusing the first side was correct, during fusing of the image on to the first side of the paper had shrunk.

Moral of the story If you want to a reliable machine ensure your paper is dry. For the best results make sure the paper is recommended for double sided copying. If the paper has an arrow on the end the packet it usually means single sided use, it may well double side but you may have problems. When you open the paper, open the reams carefully from one end, any paper left in the packet can be protected by folding the end of the packet back over and putting the paper back in the box. This is especially true of A3 paper that may hang around for months before being used.


Toners Compatible ! why Oki machines work well with our compatible toners

Oki machines are one of the few manufacturers whose toner cartridges only contain toner. The Drum unit that is replaced every 3 toners contains the developer, cleaning blade and drum. The Oki toner supply system also suits compatibles due to it being gravity fed system. A roller in the base of the toner cartridge feeds toner into the drum unit as and when required.

We have been supplying compatible Oki toners for 4 years with no detrimental effects. See our total cost of ownership page to see how you can save 33% on your running costs.

Toner Compatible? should I use them!

People assume a toner cartridge just contains toner, this is only true in a few cases. Most toner cartridges contain three components.

  • Toner, the powder that is fused on to the paper to form the image

  • Developer, a graphite based powder that regulates the amount of toner reaching the paper (similar to the nib of a fountain pen).

  • Drum, PCU, Photoconductor, a light sensitive drum.

The reason compatible toners vary in price and quality so much is down to the cartridge?

  • Has it just been refilled with toner.

  • Has it been refilled and the Drum and cleaning blade replaced.

  • Has been remanufactured with new toner, drum, cleaning blade and Developer.

The only way to know is to use the cartridges and find out what happens!

The cartridges we sell are remanufactured cartridges, that we will warrant is being fit for purpose, NO compatible cartridge will work as well as an original.


If you would like to book a service call ring 01293 537827 or email

Local printer sales, supplier new, refurbished, reconditioned and used Crawley, Horley and Gatwick
DOS are a local printer repair specialist, our experienced mobile technicians offer an on site printer installation Printer sales, supplier new, refurbished, reconditioned and used Crawley, Horley and Gatwick, Digital Office Solutions offer printers, laser printers, wide format printers and plotters from Brother, Canon, Epson, HP Hewlett Packard, Konica Minolta, Kyocera Mita, Oki, Ricoh and Samsung in Crawley, Horley and Gatwick, West Sussex & Surrey area.

Printer sales, supplier new, refurbished, reconditioned and used Crawley, Horley and Gatwick, Digital Office Solutions offer printers, laser printers, wide format printers and plotters from Brother, Canon, Epson, HP Hewlett Packard, Konica Minolta, Kyocera Mita, Oki, Ricoh and Samsung sales, supplier new, refurbished, reconditioned and used Crawley, Horley and Gatwick in Crawley, Horley and Gatwick, West Sussex & Surrey area.



Digital Office Solutions
Unit 5 Hyders Farm
 Bonnetts Lane
RH11 0NY
01293 537827
Email Us
is offered
Monday - Friday
9.00am - 5.30pm
0870 848 4040


Introductory discount voucher!


45 + vat Callout (includes half hours labour)

33 + vat per half hour thereafter

Equivalency List

Fault Codes



UK Photocopier Repairs


Quickstream Ltd T/A Digital Office Solutions,
Unit 5 Hyders Farm,
Bonnetts Lane
RH11 0NY
Telephone 01293 537827 Registered in England Registration Number 04193475
Faxscimile 01293 619934 Registered Office 87 Church Street, Willingdon BN22 0HS
Director J M Waters  Vat Registration No 858 1773 84