Terminology -- Circuit Boards

The terminology in this industry is a bewildering mess of ill-conceived and sloppily applied terms. Nowhere is that more evident than with respect to the major circuit boards typically found in laser printers. I'll attempt to clarify the subject here.

First, though, we need to clear away some clutter.

The terms 'board', 'circuit board', 'logic board', 'printed circuit board (PCB)' and 'printed circuit assembly (PCA)' all mean the same thing -- a thin, flat, usually rectangular piece of insulating material with conductive traces and electronic comonents and connectors on it. I'm partial to 'PCA' (Printed Circuit Assembly), and in writing I always use that term following a circuit board's name; e.g. Formatter PCA or DC Controller PCA. With that out of the way, let's get on with engine controllers and formatters and system boards and the like -- they're the source of much confusion.

Early Days -- The LaserJet II and Lexmark 4019

In any monochrome printer, there are two distinct functions at work. One is engine (mechanism) control; the other is page composition.

In the LaserJet II, engine control was done by the DC Controller PCA; page compositon was done by the Formatter PCA.

In Lexmark's 4019, the engine control and page composition functions were combined on a single PCA -- the System PCA.

Engine Control PCAs

HP has been fairly consistent with the use of DC Controller PCA for the engine control PCA's name.

Lexmark has made models with separate engine control and page composition PCAs. For those machines, Lexmark uses the term Engine Controller PCA, not DC Controller PCA.

HP uses the term Engine Controller PCA as well, but they reserve its use for PCAs that have the engine control function and the power supplies combined on them. Many of HP's modern crop of compact machines are constructed this way.

Formatter PCAs

Formatter PCA continues to be HP's term for a page composition PCA.

Where Lexmark has made machines with separate engine control and page composition PCAs, they've used the term RIP PCA for what HP calls a Formatter PCA. 'RIP' stands for 'Raster Image Processor'. (If you're familiar with the operation of CRT displays, you'll certainly recognize the term 'raster'. Laser printers employ rasterization as well.)

Main Logic PCA

'Main Logic PCA' is liable to mean System PCA or Formatter PCA or RIP PCA. It's a term that's best avoided, really, but it does crop up.

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