SCX-6545N full system top-right-photo

Samsung SCX-6545N, SCX-6545NX & SCX-6555 Printers

SCX-6545N minimal system top-left-photo

The Samsung SCX-6545 and SCX-6555 multifunction printer / copiers are A4 monochrome machines based on a robustly built and expandable print engine. The base unit can be desk standing but it will expand into a full floor-standing system. The print engine is monochrome (black only) giving low running costs and high reliability. Samsung's unique selling proposition is that this printer / copier is unusually cheap to own and run because it is designed for ordinary office paper - it doesn't have the overheads of A3 machines.

The print engine has paper feeder units at the bottom, feeding up the right hand side of the machine to the print-engine and emerging to a collection tray at the left just under the scanner.

SCX-6545 cross section

These machines are fast mono laser printers at heart - comparable to the HP LaserJet P4015 and M602 printers and their relative the M4555 which is a direct competitor to the SCX-6545 and SCX-6555.

SCX-6555 Printer Family

The SCX-6545 and SCX-6555 machines are largely the same hardware, they differ in that the 6555 is ten pages per minute faster. Speed is just a matter of firmware in this case, the slower printer is offered at a lower price. Very much the same situation holds between the LaserJet P4014 and P4015; they have the same engine, similar features and speed set in firmware.

The SCX-6455 print-engine has quite a heritage. The layout and principles date back to the SCX-5112 in 2003. The SCX-6322 was an enhancement and then greatly speeded up in the SCX-6345. It's a well established design and there seem to be high levels of customer satisfaction with it.

Differences with the new printers are that they are much faster and more expandable, so if your old printer is too slow you might want the upgrade. But the underlying design has proved reliable and if you are used to a machine like the SCX-6345 then your natural upgrade is to either of it's descendants: the SCX-6545 and SCX-6555. The newer printers work in a similar fashion, are still easier to use thanks to an improved control panel and have still lower ownership costs.

Maintenance

The SCX-6545 and SCX-6555 machines can look quite impressive with the copier features. The printer has a design life of a million pages, which suggests the machine is robust. For instance, rather than using rollers and a separation pad the cassettes use a triple roller with feed, separation and retard rollers. Most of the main parts are regarded as "Customer Replaceable Units".

cartridge change page iconChanging Cartridges

Print quality problems have the usual suspects:

The drum has a rated life of 80,000 pages but it is could be damaged by things like adhesive labels or exposure to light. The optical photo-conductor (OPC) is the visible shiny green roller or "drum". Damage to the drum will show up as streaks on it's surface, there is more on how to spot problems below.

Maintenance Kit

The transfer roller has a rated life of 125,000 pages and faint print might suggest a replacement - it might be possible to revive print quality by cleaning it. The transfer roller is in the right-hand side door; Samsung have made it into maintenance Kit B which comes with instructions.

If a fault is not cleared by changing rollers or a drum then cleanliness of contacts is the next most likely print-quality issue.

maintenance kit page iconMaintenance Kits

The fuser has a life of 250,000 pages, good for a printer, average for a copier. The printer will warn when a replacement is likely to be necessary. The printer will also warn if the fuser doesn't come to temperature and the user should be able to tell if the fuser roller is degenerating because the printer will work but leave irregular marks on the page. Long-life devices like fusers could fail prematurely, due to a power surge or accidental damage from labels sticking to a roller for instance.

fuser sketch

Paper feed problems are likely to be mis-set paper guides, overfilling the trays or an obstruction - check the tray flaps and the duplexer door down the right hand side. One potential irritation with these machines is that if paper does jam there are lots of places to check.

Cartridge, imaging unit, transfer roller and fuser are designed to be user changeable. Printer firmware monitors component use and warns when it needs changing. Experienced IT people can override the warnings; users should not do so because when faults do occur it could be difficult to identify why.

The printer does have a diagnostic mode. Section 4 of the service manual gives some information on how to use diagnostic mode.

scanner page iconScanner Page

Scanning

Multi-Function Printers (MFPs) are a combination of laser printer and scanner. When called on to copy the CCD scanner reads the page and directs the data more or less directly to the printer - but the network scan capability available from the touchscreen can scan-to-file or scan-to-email. Workflow software can take a series of expected business documents like customer records, delivery notes or invoices and systematically scan them to file.

Digital copying is simpler than it's analog equivalent in some respects, there is no need for a complex system of illumination, mirrors and lenses. A page is scanned either to the printer or to a file - so to identify whether the scanner or the printer is to blame for streaks or other issues in copying change the destination and see if the problem goes away.

The Duplex ADF (DADF) on these machines has a capacity towards 100 pages. This means the printer can take a substantial lose-leaf report (perhaps with a binding edge guillotined away) and copy or scan it in one run. DADFs are only provided on professional equipment and whilst this one slows down on duplex jobs (some can read both sides of a page at once, this can't) its still a substantial attraction.

Faults likely with the scanner are usually:

  • streaky scans (which usually turns out to be correcting fluid on the platen glass )
  • misfeeds in the ADF - which could be a stray blockage but will be otherwise cured by changing the pickup roller and pad.
SAM_SCX-6545_cartridges

Printing

The printer is a fairly conventional monochrome "electrophotographic" device. It uses an SCX-D6555A toner cartridge and waste bottle. The toner itself is polyester powder with carbon black as the colourant. This kind of toner can be quite complicated, with different polyesters making up the toner core to give low melt point and the shell to give the correct charge-carrying properties. These print cartridges deliver between 23,000 and 25,000 copies for under £50, at the ISO 19752 5% cover rate. The cartridge cost compares very well with most rivals and gives unusually low cost per copy. Part of the reason is that toner and drum are separate, so the toner and waste containers are simple. Samsung have also been quite modest about their pricing - they are making inroads into the copier market.

The heart of the printer is an Organic Photo-Conductor drum or "OPC".   OPCs are thin layers of plastic and dye that become conductive in the light. In this printer the SCX-R6555A imaging unit cartridge holds both drum and developer and has a design life of 80,000 pages. The printer is intended to appeal where workloads are 10 to 15 thousand pages per month so a drum will last between 6 months and perhaps a year.

SCX-6345 etc electro-photographic principle

The toner cartridge and the imaging unit both have a chip to validate Samsung as the vendor and record use. Samsung tend to call the chip a "CRUM" (Customer Replaceable Unit Memory). We are normally somewhat hostile to chipped cartridges - although we favour manufacturers original cartridges as giving less trouble. We feel it is up to users to decide whether they want manufacturer's original cartridges - not something manufacturers should enforce. The low copy costs from Samsung versions of this printer make it difficult to resent the chips.

Print Process

The OPC drum turns (anti-clockwise in the diagram). At the start of the print process it is given a strong electrical charge by a pre-charge roller. The laser scanner exposes the drum to light in areas to be printed and that charge drains away. The drum now carries a "latent image" in electrical charges.

Meanwhile the developer roller next to the OPC drum has been charged with toner. This printer uses a conventional dual-component developer. The developer is a mix of toner powder from the cartridge with iron-filing developer. The developer roller itself is a hollow aluminium roller rotating very close to the OPC and carrying the toner. Within the developer roller is another roller containing magnets which rotates somewhat faster than the outside of the developer. The developer itself contains a charge of iron filings which are attracted to the roller and move with it and the magnets inside it.

Toner powder is mixed with the developer iron filings. Toner sticks to the filings, and is carried round the developer. The OPD drum is brushed by the filings but like charges repel so if the drum and developer carry similar voltages no toner transfers. Where the charges differ toner crosses from developer to OPC and so the drum picks up an image in toner.

The drum turns to face the paper. At this point paper coming from the registration station has moved over the transfer roller which contains an attractive opposite voltage. Most of the toner powder transfers from the drum and onto the paper.

Almost immediately, the paper with it's load of charged toner moves into the fuser. The fuser holds two rollers, one of which is heated whilst the other is spring-loaded against it. The combination of heat and pressure in the fuser adheres the toner powder to the page. In principle the finished page can be ejected for the user to collect.

Document Creation

This printer comes with a duplexer and is often equipped with the optional stapler-stacker.

Rather than immediately being ejected the page may be reversed into the duplexer. It then goes back down the right hand side of the printer up and back into the registration station, this time with the unprinted side facing the drum.

If a stapler-stacker is fitted the finished page goes into a holding area until the print job is finished. The stapler can cope with up to 50 pages - which could be 100 sides of print and more than copiers are normally asked to produce.

Using a separate toner and drum cartridge.

A key difference between machines regarded as copiers and home printers is paper capacity. The copier style of machine can take a whole 500 sheet ream of paper in one go allowing it to run without user intervention for some time. Expansion trays take this further and they can be used for different types, weights and colours of paper. For instance, there can be a pre-printed coloured letterhead, ordinary paper and a dispatch label.

The printer is a fairly conventional monochrome "electrophotograpic" device.The heart of the printer is an Organic Photo-Conductor drum or "OPC". OPCs are thin layers of plastic and dye that become conductive in the light. In this printer the drum is mounted in a cartridge that also holds the developer and it has a design life of 80,000 pages. The printer is intended to appeal where workloads are 10 to 15 thousand pages per month so a drum will last between 6 months and perhaps a year.The "ink" for the machine is provided as oner powder isOPC drum is given a strong electrical charge by a pre-charge roller. The laser scanner exposes the drum to light in areas to be printed and the charge drains away.

Meanwhile the developer roller next to the OPC drum has been charged with toner. This printer uses a highly conventional two-part developer. The developer roller itself is a hollow aluminium roller rotating very close to the OPC and carrying the toner. Within the developer roller is another roller containing magnets which rotates somewhat faster than the outside of the developer. The developer itself contains a charge of iron filings which are attracted to the developer roller and move with it and the magnets inside it.

Toner powder is mixed with the developer iron filings. The toner powder sticks to the filings, and si is carried round the developer. The OPD drum is brushed by the filings but like charges repel so if the drum and developer carry similar voltages no toner sticks. Where the charges differ more toner adheres and so the drum picks up an image in toner.

The drum turns to face the paper. At this point paper comming from the registartion station has moved over the transfer roller which contains an attractive opposite voltage. Most of the toner powder transfers from the drum and onto the paper.

Almost immediately, the paper with it's load of charged toner moves into the fuser. The fuser holds two rollers, one of which is heated whilst the other is spring-loaded against it. The combination of heat and pressure in the fuser adheres the toner powder to the page. In principle the finished page can be jected for the user to collect.

sing a separate toner and rum cartridge.