JPH01165456A - Method of monitoring operation of matrix printer - Google Patents

Abstract

PURPOSE: To obtain an operation monitoring method for matrix printer in which the operational function is ensured with high reliability by monitoring the operation of at least one printing needle or pin during at least a part of the operation cycle thereof and detecting fluctuation of flux caused by the operation of the printing needle. CONSTITUTION: A magnetomotive force proportional directly to the time derivative of flux in a magnetic circuit is induced by a variation of flux in a winding 16 caused by movement of an armature. The magnetomotive force is suitably employed for determining the transition time point t1 from work stroke to return of a needle 11 and an armature 12 and the time point t2 when the armature returns back to the starting position at the end of work cycle. Two time points are determined using a detector comprising a transistor 29 and two resistors 30, 31 and connected with the winding 16. A voltage Ud appears at the output 32 of the detector and both time points t1 , t2 can be read out. Based on the information concerning to the time points t1 , t2 , a controller built in a printer can control or regulate the operating method of the printer automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for monitoring the operating method of a matrix printer.

More particularly, but not exclusively, the present invention provides printing anvils disposed in front of the printing anvils and reciprocally movable in a direction substantially parallel to the anvils, each of which can be individually operated by a respective electromagnetic operating device. Regarding a method for monitoring the operation of a matrix printer including a print head having a plurality of printing needles,
When the device is activated, the printing stylus, carried by a spring-loaded moving armature, moves in a direction toward the anvil to print dots or other graphic symbols on a record carrier placed in front of the anvil. Then, an operation cycle including a return stroke in which the printing needle returns to the retracted stop position can be performed.

Such printers already operate at very high speeds;
It would be easy to operate at even higher speeds if it could be guaranteed that increasing the operating speed would not increase the risk of failure. For this reason, efforts have been made to be able to reliably monitor the operating method of this type of matrix printer while the printer is in operation. However, no monitoring method for practical use has been proposed so far.

It is therefore an object of the invention to provide a method for monitoring the operation of a matrix printer of the type described above, which uses simple and inexpensive means and which ensures extremely reliable monitoring of the operating functions.

The method proposed according to the invention to achieve this objective consists of monitoring the movement of at least one printing needle or bottle during at least a partial cycle of the printing needle movement cycle and monitoring the associated movement caused by the printing needle movement. Its main feature is to detect changes in magnetic flux within the magnetic circuit of the operating device.

The present invention overcomes the drawbacks caused by the functional impact of printing on the transducers or methods previously proposed for monitoring the operational functions of matrix printers and detecting the movement of printing needles using optical sensors. It is.

With this method, it is possible to establish with high precision the transition time at which the printing stylus changes from the working stroke to the return stroke during the operating cycle, i.e. the point at which the printing stylus collides with the record carrier, which is dependent on the operating method of the armature that carries the printing stylus. This is because the sign of the time derivative of the magnetic flux in the magnetic circuit, which is caused by the reversal of , changes at this point.

Furthermore, with this method it is possible to easily establish the point in time at which the printing needle reaches its rest position at the end of the working cycle, either because the time derivative of the magnetic flux at this point assumes a value of zero or because the armature is repelled. This is because the sign changes and passes through the zero value.

Using the monitoring method, the method of operation of the printer can be automatically controlled according to its results. Additionally, if the printer is not performing satisfactorily, the method can be used to shut down the printer or indicate a malfunction.

Examples of different operating parameters that can be controlled or adjusted according to said monitoring of the operation of the printing stylus are the point at which a particular printing stylus operation cycle is initiated, the impact force of the printing stylus on the record carrier and the distance between the print head and the anvil surface. is included.

It should be appreciated that the present invention is not restricted to the monitoring of a single printhead, but that the proposed printing stylus monitoring can be applied to all printing styli in the printer.

The invention also relates to an apparatus for monitoring the operating method of a matrix printer of the kind described above. This device detects the magnetic flux changes in the magnetic circuit of the associated operating device caused by the movement of the printing stylus, thereby producing at least one print! The main feature is that the operation of at least one printing stylus is monitored during the operating cycle.

The apparatus comprises any suitable type of sensor for detecting said magnetic flux changes. For example, the sensor may have a Hall effect element exposed to said magnetic flux. Preferably, however, the sensor is in the form of a winding located in the stationary part of the magnetic circuit.

The advantage of using such a winding as the required sensor is that the electrical signal resulting from the sensor is proportional to the time derivative of the magnetic flux.

According to one embodiment of the invention, the sensor winding includes a winding that generates magnetic flux in a magnetic circuit. In this case, sensor functionality is obtained without providing separate sensors in the control and monitoring device.

Embodiment In FIG. 1, the reference numeral 1o generally denotes a printing needle or bottle 11 of a matrix printer of the type disclosed in the introduction.
This figure shows an electronic device for operating a computer. The printing needle 11 rests firmly on one end of the arm 12, the other end being pivoted on a pivot 13.

In practice, however, the necessary pivoting movement of the arm 12 can be obtained by an arm consisting of an elastic, flexible element fixed at one end thereof and exhibiting a stiffener of magnetic material along the main part of its length.

arm 12 forms a movable armature on device 10;
The magnetic circuit is also made of magnetic material and has two windings EA15.16.
It includes a stationary, U-shaped part 14 in which is arranged.

Reference numeral 17 designates a thrust or pressure spring located between the rigid spring abutment 18 and the armature 12 and swinging the armature 12 away from the stationary part 14 of the magnetic circuit. However, in practice, this spring is essentially built into the elastic or spring portion of the armature and moves the armature into the stationary portion 14.
can be replaced by a spring bias that attempts to hold it at a certain distance from

During printer operation, constant current I. Continuously Volume 1v21
5. Despite the spring bias acting on said armature, it is sufficiently high to hold the armature 12 in the illustrated suction position against the stop member 19.

The illustrated printing stylus 11 and operating device 10, together with a further plurality of printing styli and associated operating devices, are included in a print head of a printer, which head is arranged along a printing anvil or similar counterforce surface 20 in a small number of locations. Both can reciprocate in a direction substantially parallel to the anvil. All printing needles can be operated individually to produce dot prints or other graphic symbol prints on the record carrier 21 arranged in front of the anvil 20. The record carrier 21 is usually made of a vapor web, and a printing needle can print a code thereon using a carbon ribbon or the like.

If the illustrated needle 11 prints a code on the carrier 21, the operating device 10 is activated by delivering a short ii current pulse 11 to the winding IQ16. Due to this current pulse, the magnetomotive force generated within the magnetic circuit formed by the armature 12 and the stationary portion 14 is significantly reduced, albeit for a short time. In response to the spring bias acting on it, it starts moving away from the stationary part 14 and toward the printing anvil 2o, while forming a gradually increasing gap between the armature and the stationary part. When the current pulse 11 stops, Ti
Due to the mechanical energy obtained during the current pulse duration, the armature continues to move in that direction towards the carrier 21 until the needle 11 carried by it impinges on said carrier. At the same time, the direction of movement of the armature changes and the current I.

The armature is restored to its starting position by the attractive force exerted on it by the stationary part 14 due to the magnetomotive force generated in the winding 15.

Said current pulse i in winding 16 can be generated using the combined drive and monitoring circuit shown in FIG. As shown, one end of the winding 16 is connected to a conductor 2 to which a positive potential is applied.
a diode 2 having a switch 23 connected to the diode 2 and a resistor 26 connected in parallel to a conductor 24 at ground potential;
5 connection points. The other end of the winding 10116 is connected to the junction of a diode 27 connected to the conductor 22 and a switch 28 connected to the conductor 24. The switches 23 and 28 are both composed of movable I switches such as MOS transistors.

Using the circuit elements described above, the current pulse 11 can be given the appearance of three mutually successive parts '11, '12 and 113 as shown in FIG. 3 in a known manner. Two switches 23, 28 are closed for the duration of pulse portion '11, and only switch 28 is open for the duration of pulse portion '12. Both switches are open for the duration of pulse section '13.

The movement performed by the hand 13 during the working cycle is illustrated using a curve showing the position of the hand as a function of time.

In addition to generating the drive pulses 11, the circuit shown in FIG. 2 also serves to monitor the movement of the needle 11 during the operating cycle, which consists of an actuating stroke and a return stroke of the needle. This monitoring step detects changes in the magnetic flux in the magnetic circuit formed by the stationary part 14 and the armature 12 during the common movement of the needle and armature, which is caused by the inevitable changes in the air gap length between the stationary part 14 and the armature 12. It is done by detecting.

In the case of the circuit shown in FIG. 2, the winding 16, which serves to generate the drive pulses 11, is utilized as sensor means for sensing said magnetic flux changes. Winding 1 due to armature movement
6, a magnetomotive force is generated which is directly proportional to the time derivative of the magnetic flux in the magnetic circuit.

The magnetomotive force generated in the winding is well suited for use in determining the transition time t1 of the needle 11 and armature 12 from the working stroke to the return stroke and the time t2 of the return of the armature to its starting position at the end of the working cycle. . The determination of the two points in time is determined by the transistors 29 and 2WA connected to the winding 16.
This is done using a detector consisting of a resistor of 30°31. At the output 32 of the detector a voltage U is obtained, which is the third
The configuration shown in the figure is provided, from which both times t and t2 can be read.

The information obtained regarding time points t 1 and t 2 can be used to automatically control or adjust the method of operation of the printer using a controller built into the printer. Additionally, if one or both of the instant values indicate that the operating condition of the printer is unacceptable, this information can be used for automatic shutdown and/or fault indication of the printer.

The present invention is not limited to the above embodiments.

Various alternative embodiments are possible within the scope of the invention. For example, the senna used to detect changes in magnetic flux in the magnetic circuit of the printing needle operating device does not need to be constructed of a winding, but can also be in the form of a Hall effect element.

[Brief Description of the Drawings] Figure 1 is an outline diagram showing the structure of the matrix printer by showing the printing needle included in the print head and electromagnetic button operating device, and Figure 2 is the printing needle of Figure 1. The circuit diagram of the drive/monitoring combination that can monitor the operation of the printer by monitoring the operation of the printer, FIG. 3 shows the operation of the printing needle during the printing needle operation cycle and the various electrical signals generated in the circuit of FIG. 3 is a time chart including a plurality of curves shown in FIG. (Explanation of reference symbols) 10... Matrix printer electromagnetic operating device 11...
Printing needle 12... Arm 13... Pivot 14... Stationary part 15.16... Winding 17... Pressure spring 18... Spring abutment 19... Stopping member 2o... Anvil 21...Record carrier 22.24...Conductor 25.27 River diode 23.28...Switch 26.30.31...Resistor 29...Transistor

Claims (10)

[Claims] (1) Printing having a plurality of printing needles arranged in front of a printing anvil and capable of reciprocating in a direction substantially parallel to the anvil, each of which is individually operable using a respective electromagnetic operating device. In the method for monitoring the operation of a matrix printer including a head, when the operating device is activated, the spring-biased movable armature carrying the needle moves in a direction towards the anvil so that the needle is placed on a record carrier disposed in front of the anvil. It may be arranged to carry out an operating cycle comprising a stroke of printing a dot or other graphic symbol followed by a return stroke of the needle to its retracted rest position, at least a portion of the printing needle motion cycle. A method for monitoring the operation of a matrix printer, characterized in that the operation of at least one printing stylus is monitored during a cycle, and magnetic flux changes in the magnetic circuit of an associated operating device caused by the operation of the printing stylus are detected. (2) The method according to claim 1, wherein the monitoring step establishes a transition point at which the printing needle changes from the operating stroke to the return stroke during the operating cycle of the printing needle. . (3) A method according to claim 1 or 2, characterized in that the monitoring step establishes a point in time at which the printing needle reaches its stop position at the end of an operation cycle. (4) A method as claimed in any preceding claim, characterized in that monitoring the operation of the print head is used to automatically control or adjust the manner in which the printer operates in accordance with the results of the monitoring step. How to monitor matrix printer operation. (5) A method according to any of the preceding claims, characterized in that the monitoring step is used to stop the printer and/or indicate a failure if the operation of the printer is unacceptable. Operation monitoring method. (6) Printing having a plurality of printing needles disposed in front of a printing anvil and capable of reciprocating in a direction substantially parallel to the anvil, each of which is individually operable using a respective electromagnetic operating device. A method for monitoring the operation of a matrix printer comprising a head, in which when the operating device is activated, the spring-biased movable armature carrying the needle moves in a direction towards the anvil so that the needle moves onto a record carrier located in front of the anvil. The operating method monitoring device may be adapted to carry out an operating cycle including a step of printing a dot or other graphic symbol on the needle, followed by a return step of the needle to its retracted rest position. The operation of the at least one printing needle is monitored during at least a partial cycle of the printing needle movement cycle by detecting magnetic flux changes in the magnetic circuit of the associated operating device caused by the movement of the needle. Features: A monitoring device for the operation method of a matrix printer. (7) An operating method monitoring device for a matrix printer according to claim 6, further comprising a wire-shaped sensor disposed in a stationary portion of the magnetic circuit. (8) The apparatus according to claim 7, wherein the winding functioning as the sensor is formed by a winding used to generate magnetic flux in a magnetic circuit. (9) The apparatus according to any one of claims 6 to 8, wherein the apparatus is adapted to detect a transition from an operation cycle to a return cycle that occurs during a printing needle operation cycle. Device. (10) A method for monitoring the operation of a matrix printer according to any one of claims 6 to 9, characterized in that the apparatus is adapted to detect when the printing stylus reaches its operating position upon completion of an operation cycle. Device.