Updated: Nov 20, 2018
Critical Definitions ( Longer list Below)
Controller- The electronic assembly that sends commands to and receives commands from other devices.
Control Panel- The display and switch panel on a printer that indicates the status of the control subsystem and may be used to reconfigure the machine settings.
DC power supply- (direct current) This supply converts AC power into direct current at the appropriate voltage level to power electronic devices. These currents are commonly +5V, -5V, +24V.
Dpi- (dots per inch) A measure of resolution of print imagery. An image on a page is made of tiny dots where along a given vertical or horizontal line there are 1200 dots per inch.
Engine- The engine provides all the mechanical and electromagnetic functions to allow a signal sent from the logic board to the engine, which are transferred to independent dots on the paper.
Exit roller- (delivery roller) The exit roller is part of the fuser or delivery assembly of the printer which helps to drive paper to the output tray.
Functional subsystems- Groups of modules that handle the main functions of a laser printer. Laser printer problems can be attributed to a subsystem failure. The four primary subsystems of laser printers are as follows:
Paper handling- The mechanisms of the printer dedicated to moving paper into the machine, through the printing process without skewing, wrinkling or jamming, and out the exit. This subsystem includes the input cassette, pickup assembly, registration assembly, fuser, and –in some machines- delivery assembly.
Image formation- The modules that transfer and convert the data from the host computer into a toner image on the page. This subsystem includes the logic board, DC controller, laser, scanner, cartridge, transfer corona wire or transfer roller, and fuser.
Power- The modules of the printer that provide electrical power to the other subsystems. These include the AC-, DC-, and high voltage power supplies.
Control- The control subsystem ensures that each of the other subsystems receives the appropriate input needed, at the precise moment required. If an input fails to arrive within the precise time, the control system issues an error message, waits for the input, and/or stops the machine. The control system includes the DC controller, solenoids, photo interrupters (paper sensors) thermistor, fiber-optic cable or sensor, error display, and other control devices.
Fuser- The most common failed assembly in most laser engines or copiers is the fuser. The fuser melts toner onto the paper. In early printers it includes upper and lower rollers, a heating element, temperature sensing circuitry, a paper sensor, and an exit assembly. In later machines, instead of using a halogen lamp, heat is provided by a fixing film assembly using a heating element to fuser the image onto the page.
High Voltage Power Supply-Generates three levels of very high voltages for use by the image formation subsystem. Early printers with coronas generate –6,000 V for the primary corona wire inside the toner cartridge, +6,000 V for the transfer corona wire, and –600 V for the developer cylinder bias, also inside the cartridge. Later printers need only produce about –1,000 V, +1,000 V, and –600 V since they use more efficient charge roller technology.
Interface Board (PCA)-The electronic circuit board translates computer code from the host into a form that can be printed by the engine.
Motherboard- It is also called an I/O board, interface PCB, formatter board, or logic board. It contains computer memory, at least one microprocessor chip, the printer language interpreter, and all of the logic needed to specially instruct the DC controller in the nature of the image to be printed. Interprets simple ASCII coded instructions from the host computer and forms a dot-by-dot image of the page to be printed.
PCB-(printer controller board)-A circuit board made from the insulating laminate coated with conductive traces and pads making up the electronic circuit into or on which components or integrated circuit elements are mounted.
PCL-(printer control language)-HP’s proprietary programming language offered with Hewlett-Packard LaserJet Printers. In the early HP’s, while the graphics capabilities of PCL are somewhat limited, it requires much less data processing for the printer interface to format text for printing. Consequently, PCL-outfitted printers typically print faster and are less expensive than PostScript printers. Recent versions of PCL, PCL5, and 6, offer most of the same graphics and text features of PostScript for the PC world.
Pickup Assembly-The device which lifts one page of paper from the cassette or tray and moves it to registration in the early stage of paper handling. The assembly includes at least one pickup roller and might also include a method of separating the top page from the rest of the stock.
Pickup Roller-The rubber roller or rollers are designed to pick up a sheet of paper. When rollers become sufficiently coated with foreign matter or polished by wear, customers will likely complain about frequent paper jams.
Power Supply-The module which outputs power required for printer operations. Printers contain three power modules (or those functions within one or more circuits): AC, DC, and high voltages power supplies.
Registration Assembly- The device responsible for ensuring that the paper enters the image formation process at the proper time. Registration is accurate when the top margin of the image is correct.
Scanner-The scanner module sweeps a stream of lasers on and off onto the OPC drum, one line at a time. Each stream or “raster” results from one facet of a spinning, multisided mirror mounted on a high precision motor, passed through several other mirrors and lenses.
Other Helpful Resources
Full List Printer Definitions
10/100- Used to describe the speed of the network or interface speed capable of sending or receiving data at either 10 megabits or 100 megabits
10bt Pronounced "10 base T". The RJ-45 connector used on an Ethernet network: capable of transmitting data at megabits per second
A4 (European paper sizes A,B)European (Japanese, etc.) use letter designations (in millimeters) for specific paper sizes. These are different than the US designations (Letter, Legal, Ledger).
ADF Automatic Document Feeder
ADF assembly Automatic document feeder assembly used on MFP or AIO printers to feed documents into the printer to be scanned or copied on the flatbed scanner portion of the printer.
ADF Unit Automatic Document feeder.Part of MFP or AIO printers which feeds the paper into the scanner or flatbed for copying or scanning documents.
Aftermarket The sale of service and supplies to customers on an ongoing basis.