Line printer

A line printer is a high speed printer that is not sequentially like a daisy wheel printer, but to take "a hit" on paper one line.

Operation

The different versions have in common is that many more or fewer types open simultaneously at different columns in a row. In between, a ribbon or a colored cloth is attached either. However, they are still in operation for bulk orders, especially if copies are required.

Common to all is the high noise level work, which is why line printers are usually placed in separate rooms or with acoustic enclosures.

History

First IBM models had a type bar or rod. All types of character sets ( uppercase letters, numbers and a few punctuation marks) were superposed according to frequency of her, each print column had its own. These rods were asked for each column position on the correct character and at the same time struck for the whole line. The wedding of the line printer was as peripheral to the mainframe ( mainframe computers ) in the 1960s to the 1980s. For smaller companies with high-volume printing, there were also matrix printer that had a needle comb over the entire line width instead of a movable print head, shuttle matrix printers. Within certain limits, they were even graphics capability, could different (variable) bring fonts to paper and dominated important font attributes.

The line printers were replaced mostly by modern laser printers that can print an entire page in one operation both with (variable ) font as well as lines and charts ( form creation ) in contrast - and are also much quieter. However - punches are with them impossible, so is aided by the with so-called "multiple originals ".

Building types of current models

Today stuck developed representative of the mechanical line printers are used. These are of the drum or roll printer and the belt or chain printer. Here Druckjoch rotate in either rollers or chain types at very high speed in front of the paper.

The pressure chain contains the complete or part of printing character set up to five times. For each column, there is a solenoid-operated hammer (usually from the back of the paper ) strikes at the right time. The hammer blows for all characters on a line so do not take place exactly at the same time. The vertical paper transport takes place sakkadisch ( jerky ) and continued only after the complete execution of the entire line.

Variable character sets or character widths ( corresponding to the print columns The default is ten characters per inch in six ( or "narrow" eight) lines per inch ) were not possible with these machines. They have been used primarily for printing on continuous paper.

• Printer