Chapter 2. Principles Of Operation; Scope; Basic Functions And Circuit Locations; Principle States Of Operation - Printronix p300 Maintenance Manual

2–1. Scope
a. General
The information in this chapter will provide you with a basic understanding of printer functions.
b. Organization of This Chapter
Printer operation is explained for each of the three principal states of operation: the buffer load state, the
print state, and the paper feed state. Also discussed under separate headings are ribbon transport, power
supply (both of which operate in more than one state of operation), and hammer driver circuits.
2–2. Basic Functions and Circuit Locations
Basic printer functions and their relationships are shown in Figure 2–1. The physical location of the cir-
cuitry in Figure 2–1 is listed in Table 2–1 .
2–3. Principal States of Operation
NOTE: The bit numbering discussed in the following paragraphs uses a
Printronix convention. Bit 1 corresponds to bit 0 in normal convention. Other
bits can be converted by subtracting 1 from the Printronix bit number.
The following states of operation are required for the printer to perform its basic function. A detailed dis-
cussion of each state is provided in subsequent paragraphs.
a. Buffer Load State
Before it can print, the printer receives and temporarily stores a line of data from the host computer.
b. Print State
Information received from the host computer is printed as a complete line by advancing the paper one dot
row at a time within the character line.
c. Paper Feed State
The paper advances to the next line, the top of form, or to a line specified by EVFU command.
P300/P600 Principles of Operation
CHAPTER 2
PRINCIPLES OF OPERATION
2–1