Printing methods and apparatus
AssigneeInternational Computers Limited
InventorBasil Sidney Munday
Life of this patent
Estimating the term…
Abstract
In printing apparatus in which a line of characters is printed on a record medium, by means of differentially timed operation of a line of print hammers, as the characters pass predetermined columnar positions of the record medium, the character font size can be changed. On each change of front size, a control circuit adjusts the timing of the actuation of the hammers so that the number of printing cycles necessary to print a line of characters is varied according to the font size used.
Claims5
Apparatus for printing on a record a line of characters from one of a plurality of interchangeable fonts of type, each font consisting of characters of the same size, different fonts having characters of different sizes respectively, the required pitch spacing of characters in a line being dependent upon the particular font from which the characters are selected, the apparatus including means for supporting the record;
- a plurality of print hammers arranged adjacent the record in a line parallel to the line in which the characters are required to be printed and being spaced apart at constant pitch, driving means engageable with a type carrier having a member carrying the characters of a single font to drive that member to move the characters in sequence past each of the hammers during a printing cycle;
- selectively operable shifting means for producing a lateral displacement between the record and the hammers in the direction of the printing line;
- switch means settable in accordance with the size of the characters of the engaged type carrier and control means effective to select the hammers to be operated at those time instants when characters are respectively in their required positions in the line during the cycle, the control means being further arranged in response to the setting of the switch means to operate the hammers to print all the characters of a line in a single cycle if the characters are of a first size requiring the spacing of the characters in the line to correspond to the pitch spacing of the hammers, to operate the hammers to print the line of characters in at least two cycles if the characters are of a second size requiring the spacing of characters in the line to be less than the pitch spacing of the hammers and to operate the shifting means to produce a lateral displacement equal to the required pitch spacing of characters in the line between successive ones of those printing cycles required to complete the printing of the line.
A method of printing lines of characters on a record includes the steps of providing a printing apparatus with interchangeable type fonts having characters of different sizes respectively;
- with a line of hammers of predetermined constant pitch arranged parallel to the record and aligned with a line to be printed and with means for recognizing the size of characters in a font in use;
- moving all the characters of the font in use respectively past the hammers during each of a succession of print cycles and actuating the hammers selectively to cause characters to be printed in the line, the method further including, if the character size of the font in use is recognized as requiring the characters to be printed at a spacing corresponding to the hammer pitch, printing all the characters of the line in a single print cycle and if the character size of font in use is recognized as requiring the characters to be printed at a spacing which is a fractional part of the hammer pitch, printing the characters of the line in more than one successive print cycles and producing relative movement in a direction parallel to the line between the record and the hammers between the successive print cycles, the extent of the relative movement corresponding to that fraction of the hammer pitch required for the character spacing.
Dependencies are inferred from the claim text.