HP LaserJet Enterprise 500 Maintenance Manual - Page 218

Printing Mechanism

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Chapter 7 Printing Mechanism Printing Mechanism While the principles of line matrix printing are easy to state, the act of printing dots accurately from a rapidly oscillating shuttle onto a vertically moving piece of paper requires complex timing and coordination between printer logic and the printing mechanism. The printing mechanism consists of the shuttle frame assembly, the ribbon transport system, and the paper transport system. Shuttle Frame Assembly The central element of the printing mechanism is the shuttle frame assembly, which houses the hammer bank assembly and the shuttle drive motor. (See Figure 45.) Shuttle Frame Assembly Hammer Bank Assembly Counterweight Assembly Connecting Rod Shuttle Motor Guide Shaft Figure 45. Shuttle Frame Assembly Hammer Bank Assembly The hammer springs are grouped in comb-like assemblies mounted on a solid hammer bank. The number of hammer springs per hammer spring assembly and the number of hammer spring assemblies on the hammer bank vary according to printer model: • LineJet 500Q and LineJet 500P: seven 4-hammer assemblies, for a total of 28 hammer springs • LineJet 1000Q: six 10-hammer assemblies, for a total of 60 hammer springs • LineJet 1500Q: six 17-hammer assemblies, for a total of 102 hammer springs Shuttle Drive Motor The shuttle drive motor is built into the shuttle assembly casting and drives two connecting rods on a crankshaft. The small end of one connecting rod 218

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218
Chapter
7
Printing Mechanism
Printing Mechanism
While the principles of line matrix printing are easy to state, the act of printing
dots accurately from a rapidly oscillating shuttle onto a vertically moving piece
of paper requires complex timing and coordination between printer logic and
the printing mechanism. The printing mechanism consists of the shuttle frame
assembly, the ribbon transport system, and the paper transport system.
Shuttle Frame Assembly
The central element of the printing mechanism is the shuttle frame assembly,
which houses the hammer bank assembly and the shuttle drive motor. (See
Figure 45.)
Figure 45. Shuttle Frame Assembly
Hammer Bank Assembly
The hammer springs are grouped in comb-like assemblies mounted on a solid
hammer bank. The number of hammer springs per hammer spring assembly
and the number of hammer spring assemblies on the hammer bank vary
according to printer model:
LineJet 500Q and LineJet 500P: seven 4-hammer assemblies, for a total
of 28 hammer springs
LineJet 1000Q: six 10-hammer assemblies, for a total of 60 hammer
springs
LineJet 1500Q: six 17-hammer assemblies, for a total of 102 hammer
springs
Shuttle Drive Motor
The shuttle drive motor is built into the shuttle assembly casting and drives
two connecting rods on a crankshaft. The small end of one connecting rod
Shuttle Frame
Assembly
Hammer Bank Assembly
Counterweight Assembly
Connecting Rod
Guide Shaft
Shuttle
Motor