DE4221273C2 - Control device for printing needles of a matrix print head driving electromagnetic coils or for printing wire drivers - Google Patents

Description

The invention relates to a control device for Electromagnetic coils driving the printing needles of a matrix print head or for print wire drivers.

It is known in matrix printers and also on machine tools the organ transferring an operation on a sled to arrange and to drive the carriage back and forth. However, this sled speed is not possible to keep completely constant. Practice shows that Changes in speed are inevitable. For matrix printers these speed changes need to be achieved uniform print image are taken into account.

DE 39 22 616 A1 is a circuit arrangement for a matrix printer known, at least for all Print elements that match the print grid, one Delay arrangement is provided, which is the pressure signal for the print element concerned by one of the print head speed dependent time is also delayed to start up and To be able to print out the print head precisely. A preferred embodiment of the delay arrangement uses one Counter that is also used for the activation time of the magnet as well as a pause time that ensures that the maximum actuation frequency of the pressure elements is not is exceeded. With this known circuit arrangement however, the delay time can no longer be influenced, as soon as the deceleration process is started.

The invention specified in claim 1 is based on the object the control device for printing needles of a matrix print head driving electromagnetic coils or pressure needle drivers with to provide such a delay circuit with Changes in the delay time value during implementation the actual delay time are constantly taken into account can.

This object is satisfactory with the invention Way solved.

This is an advantageous embodiment of the invention given that both the delay time and the drive time can be set on separate time bases via separate clock lines are.

An embodiment of the invention is in the drawing shown and is described in more detail below. The only Figure shows a block diagram.

A clock 1 is derived from a microprocessor, not shown in any controller of a matrix printer, and data is transmitted to a data bus 1 a. Accordingly, a clock 2 and also a clock 3 are derived from another addressing of the microprocessor. Furthermore, an oscillator clock 4 is generated.

The data bus 1 a transmits data to a delay time register 5 , an activation time register 6 and a register present in a clock divider 7 .

The data coming from the delay time register 5 are transmitted to a delay generator 12 via first data lines 8 and the data coming from the activation time register 6 via second data lines 9 .

The clock divider 7 contains the time base for the delay time, the frequency of which is transmitted on a clock line 10 a and a clock line 10 b. Here, the clock line 10 a forms the basis for the delay time and the clock line 10 b forms the basis for real time.

During the circuit section described above only once is present is the circuit section described below in a number equal to the number of electromagnetic coils or driver circuits or printing needles, which in a matrix print head is present.

Accordingly, branches 11 are made from the first and second data lines 8, 9 and from the clock lines 10 a, 10 b.

The delay generator 12 comprises a delay time comparator 13 , a real time comparator 14 , a step counter 15 , an output 16 of the step counter 15 being connected both to the delay time comparator 13 and to the real time comparator 14 .

The clock lines 10 a and 10 b lead to a control logic 17 , into which the comparator outputs 18 a and 18 b of a delay time comparator 13 and the real time comparator 14 are also guided.

The overall circuits described above work as follows: The required value is written into the activation time register 6 . This time value is specific to each printhead and is not changed during the printing process. The current value is z. B. 200 microseconds.

The value for the delay time register 5 , which is calculated depending on the carriage speed of a matrix printer in the mentioned microprocessor, is always described before the activation of the delay timer 12 , and this value can also be changed after the activation of the delay timer 12 , ie the time can either extended (delay) or shortened, ie delayed negatively. After the delay time register 5 and the activation time register 6 are loaded, the printing process can begin. When a print command is present, the delay timer 12 is started with a start signal 19 of a data line 19 a. With the preset clock of the clock line 10 a, the pedometer 15 is incremented until a comparison between the output 16 (A) and the output (B) of the delay time register 5 shows that A <B = "1" and the delay time is switched off , ie is limited. The module consisting of the control logic 17 , the step counter 15 and the real time comparator 14 is also started with the same signal, whereby the step counter 15 set to zero is incremented again, the time base being based on the clock line 10 b. This is the time for energizing the electromagnetic coil. Then the incrementing process is repeated by the step counter 15 until the real time comparator 14 at the comparator output 18 b is again logic "1".

This process means that the energization time (activation time) has expired, e.g. B. the aforementioned 200 microseconds.

The signal obtained is fed in a timely manner via a connection 20 to the driver circuit or the respectively connected electromagnetic coil, which effects the pressure on the paper via an armature and a pressure needle.

Claims (2)

1. Control device for print needles of a matrix print head driving electromagnetic coils or print wire drivers with a delay circuit ( 12 ) which, when triggered by a print signal after a delay which is determined by the print head speed, starts a control signal for the direct mechanical control of the associated printing element, and in a step counter ( 15 ) and control logic ( 17 ) are connected such that a variable delay time via the step counter ( 15 ), the control logic ( 17 ), a delay time comparator ( 13 ) and a delay time register ( 5 ) can be set and a drive time for the Pushpin electromagnets or pushpin driver circuits can be determined via the pedometer ( 15 ), the control logic ( 17 ), a real time comparator ( 14 ) and an activation time register ( 6 ), the delay time value of e. Stored in the delay time register ( 5 ) in a microprocessor can be continuously updated and changes in the delay time value are taken into account during the realization of the delay time by the delay circuit ( 12 ). 2. Control device according to claim 1, characterized in that both the delay time and the drive time on separate time bases via separate clock lines ( 10 a, 10 b) can be determined.