DE3744263A1 - CHARACTER GENERATOR FOR A PRINTING DEVICE WITH A MATRIX PRINT HEAD - Google Patents

Description

The invention relates to a character generator for a Druckvor direction with a matrix print head, in particular with a Ther Print head in a typewriter or office machine of a similar design the type specified in the preamble of claim 1.

With most conventional pressure equipment, with which several different character patterns can be generated and where no mechanical fonts are used printing by converting from a processing computer-supplied character code data in the output characters speaking dot patterns that are stored in advance.

This principle is used for example in thermal printers, needle Dot printers, laser beam printers and the like applied.

With such printers, the characters in the different Fonts through the use of character pattern generators or character generators for the respective different font types are printed, alienating the character pattern (Italics, double width, narrow font) are possible.

DE-OS 35 04 937 is such a character generator read-only memory (ROM) or read / write memory (RAM) as Cassette or plug-in unit known to be removable or replaceable bar connected to a socket attached to the pressure device becomes.

The well-known imaging devices that both have a fixed built-in as well as an interchangeably arranged characters generator, all have the disadvantage that the characters preparation via a separate from the character generator  ordered control device, e.g. B. via the microprocessor, which also includes the printing unit carriage, the platen, the ribbon drives etc. controls. This threatens to overload this tax facility due to the many functions to be controlled, which in a system design must be taken into account or prevented must become. These character generators also have the Disadvantage that their maximum memory size and the storage or Optimization procedure of the stored fonts beforehand must be determined.

The invention has for its object a character generator to create with which the efficiency and the reliability speed of the known printing devices with matrix printers increased becomes. This object is characterized by the in claim 1 drew invention solved.

Since the microprocessor co-located in the character generator Preparation of the character matrix takes over the known arrangements fewer lines required. Hereby the central control unit and the pressure control direction (Print Controller) is relieved, which means that the Performance of the machine is increased. Still allows the character generator a longer line routing without the Reliability of the circuit arrangement is impaired.

Because the character generator and control device are one unit form is not a commitment to a specific maximum memory size, on a certain microprocessor and / or certain Optimization process required.

Further advantageous refinements of the subject matter of the invention can be found in the further subclaims. The invention will be described in more detail below using an exemplary embodiment wrote.  

Fig. 1 shows an input keyboard 1, the generated character code data and control commands via an unillustrated input buffer of a central control unit (CPU) 2 are fed. This control unit is operatively connected to a program memory (ROM) 14 , a read-write memory or working memory (RAM) 15 and a printing control device 3 in a known manner. This Drucksteuereinrich device 3 (z. B. a one-chip computer) contains drivers z. B. for driving a printing unit carriage 4 , for advancing a paper roll 5 and for driving an ink ribbon device 6 . In addition, in the housing 13 of the machine, sockets 9 , 17 are provided for character generators 10 , 16 designed as interchangeable fonts, which are operatively connected via a line 8 with a matrix print head 12 and the pressure control device 3 . This matrix print head is in particular a thermal print head.

The interchangeable character generators 10 , 16 each have their own microprocessor 18 , 19 , so that the preparation of the character matrix can be carried out directly in the respective character generators 10 , 16 . This has the great advantage that the matrix print head 12 is controlled directly by the respective character generator 10 , 16 . As a result, the central control unit 2 and the printing control device 3 are greatly relieved. In addition, only a few data lines are required by the so-called intelligent character generator 10 , 16 .

Due to the interchangeability of two ( 10, 16 ) or more character generators, the user can select any font in any way, which greatly expands the field of application of such a device.

In order to change the character generators 10 , 16 at z. B. prevent multiple users of the machine, it is appropriate to provide several sockets for different character generators. In the simplest case, the fonts can consist of a single-chip computer. The character information is then in its mask ROM. A font can also consist of a microprocessor with ROM and RAM. The matrix information of a character set is then accommodated in the ROM. Another character set can then be loaded from outside into the RAM memory. The individual elements of the fonts could be accommodated in a cartridge or in the form of check cards (using SMD technology).

Claims (3)

1. Character generator for a printing device with a matrix printhead, in particular with a thermal printhead in a typewriter or office machine of a similar type, with an input keyboard, with a central control unit and a pressure control device, characterized in that the character generator ( 10 , 16th ) contains its own microprocessor ( 18 , 19 ). 2. Character generator according to claim 1, characterized in that it ( 10, 16 ) is designed as an interchangeable font and in plug sockets ( 9 , 17 ) of the clothing ( 13 ) can be inserted. 3. Character generator according to one of the preceding claims, characterized in that further character generators ( 10 , 16 ) with any fonts in separately ten sockets ( 9 , 17 ) of the clothing ( 13 ) are arranged interchangeably.