DE2341754A1 - DRIVE FOR THE PRINT HEAD OF A PRINTING MACHINE - Google Patents

Description

Drive for the print head
a printing press

The invention relates to typewriters or printing machines in which, during operation, a writing or printing head is moved back and forth with respect to the material printed by the printing head. Under the term print head
Heads are to be understood which print by means of members movable by the stop, for example hammers and magnetically driven needles, heads which press with heat, light
and other forms of electromagnetic radiation, heads that print with the deposition or attraction of charged toner particles, and any other head that deals with
Have marks made on a material. Furthermore, a print head should also be understood to mean a head which is provided with a combination of the types of marking mentioned above
is working. Examples of such printing machines are typewriters which work with a ball head (gold ball print head), and those digital printers, e.g. B. Line printers, in which the print head is relative to the material to be printed
bev / egt.

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It is already known to bring about the relative movement by means of a drive which comprises an electric motor to which an endless belt is connected via a gear, to which the print head is attached. The drive motor

by
is controlled / mechanically operated control circuits which determine the amount of movement in one direction and the reversal of movement after movement of a certain amount. The known drive has the disadvantage of being very complex and expensive, and also the disadvantage of a limited speed due to the inertial forces in the drive. It has also already been proposed to generate the relative movement by means of a rod made of highly permeable magnetic material, which is controlled by a solenoid passes through to which the print head is attached. This proposal has the disadvantage that the weight of the print head must be low because of the value of the flux density of the magnetic field. The flux density cannot be increased to such an extent that an acceleration of a normal print head together with the solenoid is possible, at which the inertia and the static frictional forces are exceeded to such an extent that a speed comparable to the known drives is achieved. In addition, the rod made of magnetic material is heavy and, in terms of the effort required to produce the usual step width, expensive.

The invention is based on the object of a simply constructed and inexpensive drive for the print head of a Specify printing press. This task is according to the invention solved by the means specified in the main claim. Advantageous refinements of the solution according to the invention are set out in the subclaims marked.

In the following the invention with its advantageous details is based on schematically illustrated embodiments explained in more detail. In the drawings show:

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Fig. 1 is an isometric view of a first embodiment of a drive according to the invention;

FIG. 2 shows a section along the line A-A through the drive according to FIG. 1 together with a circuit diagram for the control the operation of the drive serving circuits;

3 shows a section along the line B-B through the drive according to FIG. 1;

Fig. 4 is an isometric view of a second embodiment of a drive according to the invention;

5 shows a section along the line AA through the drive according to FIG. 4 together with a circuit diagram for controlling the operation of the drive and the print head
serving circuits;

6 shows a section along the line B-B through the drive to B'ig. 4, with the side cover of a position sensor removed;

Figure 7 is an isometric view of a third embodiment a drive according to the invention;

8 shows a section along the line A-A through the drive according to FIG. 7 together with a circuit diagram for the control the operation of the drive serving circuits;

9 shows a section along the line B-B through the drive according to FIG. 7;

Figure 10 is an isometric view of a fourth embodiment a drive according to the invention;

11 shows a section along the line A-A through the drive Fig. 10 together with a circuit diagram of those used to control the operation of the drive and print head Circuits;

Fig.12 shows a section along the line B-B through the drive 10 with the side cover of a position sensor removed.

The drive 10 shown in Fig. 1 comprises a frame 12, which has a first elongate member in the form of a rod of rectangular cross-section and made of magnetic material, e.g. B, soft steel, as well as two other elongated parts in the form

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of rods 16, of rectangular cross-section and made of magnetic material, e.g. B. soft steel, and includes two end plates 18, which connect the rod 14 to the rods 16. At each end of the frame 12, a bobbin 20 is not made on the rod 14 attached magnetic material, on each of which a wire spool 22 is wound, on the basis of which the carriage or Frame acts as an electromagnet.

2 shows that the coils 22 are connected to a rectifier bridge 26 via a smoothing circuit 24 which in turn receives a mains voltage of 220 V via a switch 28.

A bobbin 30 is also slidably mounted on the rod 14, the side cheeks of which are covered with a shock-absorbing material 34 are occupied. On the bobbin 30 is an electrical Conductor wound in the form of a solenoid coil 32. A A conventional 7 by 5 matrix printhead 36 is attached to the spool so that it overlies the top edges of the rods 16. The solenoid coil 32 is connected to the output of a control circuit 40, which has a control input 41 to a non Position control circuit shown and is connected with further inputs to the output of a rectifier bridge 42. The input of the rectifier bridge 42 is connected to the output of a voltage-reducing transformer 44, the Input via a switch 46 receives the mains voltage of 220 V.

In operation, the energized coils 22 generate a magnetic field between the rod 14 and the rods 16. This magnetic field The field drives the solenoid coil 32 together with the bobbin 30 and the printhead 36 in the direction of the longitudinal axis of the Rods 14 and 16 miVone speed and in one direction, which depend on the size and direction of the current flow through the solenoid coil 32 determined by the control circuit 40. The control circuit 40 controls the speed of the

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Back and forth movement of the printhead 36 between a position in which the bobbin 30 is on one of the two bobbins 20 is applied, and a position in which the bobbin 30 is applied to the other bobbin 20 by generation a repeated symmetrical waveform, the shape of which changes the speed and direction of the print head 36 certainly.

The control input 41 of the control circuit 40 is controlled by other, not shown circuits, which to printing material, not shown, and printhead 36 drive seven consecutive back and forth strokes of the print head 36 for printing a line of characters guide the material.

Instead of or together with the circuit to which the solenoid coil 32 is connected, the circuit to which the coils 22 are connected can be controlled.

The drive 10 shown in Fig. 4 has the same frame 12 with rods 14 and 16, end plates 18, bobbins 20 and Coils 22 like the drive explained above and shown in FIGS. 1, 2 and 3. From Fig. 5 it can be seen that the coils 22 via a smoothing circuit 24 to a rectifier bridge 26 are connected, which receives a mains voltage of 220 V via a switch 28.

On the uppermost of the two bars 16, a coil body 46 is slidably mounted, on which an electrical conductor in Form of a solenoid coil 48 is wound. The coil body 46 is on a U-shaped saddle 50 made of non-magnetic Material attached, which by means of four pairs of rollers 52 on the Rod 14 is slidably mounted. The print head 36 is attached to the saddle 50.

A band 53 made of stiff, non-magnetic material is one of the two at both ends on the side cheek

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Bobbin 20 attached. The band 53 extends through a band sensor 54, which has a row of seven light-emitting diodes 56 on one side of the belt 52 and a row seven photoelectric diodes 58 on the other side of the belt in parallel with the diodes 56. The band 53 is in seven lines perforated in the longitudinal direction, so that a seven-bit tape is formed in which each signal out of seven Bits is a code which represents the position of this signal in relation to a zero signal which is applied when the saddle is applied 50 is detected on the two bobbins 20 at the ends. The connections of the light emitting diodes 56 and the Photoelectric diodes 58 are connected to a control circuit 62 via a cable 60. The control circuit 62 has also a connection to the solenoid coil 48 and input connections for pressure data via which the codes are transmitted representing the characters to be printed. V / continue the control circuit 62 has connections to which the inputs of the print head 36 are connected. Finally is the control circuit 62 is connected with two inputs to the output of a rectifier bridge 42, which in turn is connected to the Output of a transformer 44 is connected, the input of which receives the mains voltage of 220 V via a switch 46.

The second drive works in a similar way to the drive explained above. The print data transmitted to the control circuit 62 include control signals such as B. "start of print", "end of print", "space", "tabulation" and "carriage return", which with the Seven control inputs from the tape sensor 54 are compared to determine the amplitude and polarity of the output to the solenoid coil 48 DC voltage and the operation of the print head 36 to control.

The type of fastening of the print head 36 used in the second embodiment of the drive has the advantage greater mechanical stability.

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The print data transmitted to the control circuit 62 can be written in any standard code, e.g. B. the ASCII code.

Those transmitted from the control circuit 62 to the solenoid coil 48 Voltages can vary in polarity and amplitude, direction or speed of the printhead 36 to control, and can set a pulsed duty cycle and a pulsed amplitude according to the "tabulation" or Have "carriage return" signals.

Instead of or together with the circuit to which the solenoid coil 32 is connected, the solenoid coils 22 connected circuits can be controlled.

The third drive 10 shown in Figures 7 to 9 comprises a rod 12 made of magnetic material, e.g. B. soft Steel, a tube 14 of magnetic material, e.g. B. soft steel, with an axial slot 16, see Fig. 7, in ' the tube 14 and two circular end plates 18, which are also made of magnetic material, e.g. B. soft steel exist and connect the tube 14 to the rod 12 coaxially. On the Rod 12 next to the end plates 18 sit circular bobbins 20, each of which has a wire coil 22, which is shown in FIG in the manner explained above via a smoothing circuit 24, a rectifier bridge 26 and a switch 28 is fed from the 'network, so that the rod 12 is an electromagnet forms.

A coil body 30 provided on its side cheeks with a shock-absorbing material 34 is displaceable on the rod 12 stored and carries an electrical conductor in the form of a wound on the bobbin 30 solenoid coil A conventional seven vertical matrix print head 36 is by means of two L-shaped brackets 33 made of non-magnetic material attached to the bobbin 30 so that it is above the upper

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edges of the axial slot 16 in the tube 14 is located. Two not magnetic ball bearings 34, see FIG. 9, are mounted between the printhead 36 and the tube 14. The solenoid coil 32 is connected to the output of a control circuit 37, which has inputs 38 to a position detection circuit, not shown is connected, which is the position of the bobbin 30 in relation to a fixed point or a fixed position to control the supply of current to the solenoid coil 32. The control circuit 37 has outputs 29 which are connected to the print head 36, and inputs 40 which are connected to a Source for print data are connected. The other inputs 41 of the control circuit 37 are connected to the output of a rectifier bridge 42 connected. The input of the rectifier bridge is connected to the output of a voltage-reducing transformer 44 connected, the input of which receives the mains voltage of 220 V via a switch 45.

In operation, the magnetized rod 12 generates a magnetic field between the rod 12 and the tube 14. This magnetic field Field drives the solenoid coil 32 together with the bobbin 30 and the printhead 36 in the direction of the coaxial Longitudinal axis of the rod 12 and the tube 14 at a speed and in a direction which is different from that of the not shown Position Detection IBD Hold and Control Circuit 37 determined size and direction of the current flow through the solenoid coil 32 depend. The control circuit 37 controls the speed of reciprocation of the print head 36 between a position in which the bobbin 30 rests against one of the two bobbins 20, and a position in which the bobbin 30 rests against the other of the two bobbins 20, by generating a repeated, symmetrical Waveform, the shape of which determines the speed and direction of the printhead. The control circuit 37 controls the power supply to the solenoid coil 32 automatically so that the print head 36 is automatically returned to an initial position, which is one of the two extreme positions at the end of the movement of the print head along the magnetized rod 12. From-

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initial positions into which the print head 36 is automatically returned may lie at predetermined locations along the axis of the rod 12. The control circuit 37 is controlled by others Controlled circuits, not shown, which drive the material to be printed, not shown, and the print head 36 control so that the printhead prints a five-column character and one at seven consecutive character positions Leaves blank space of two character positions on the material. The control circuit 37 can supply power to the solenoid coil 32 so that the print head 36 after at least one character position equivalent movement automatically to one character position is moved to make it easier to read what has already been printed. The control circuit 37 can control the print head 36 also control so that the printhead moves automatically by one character position, then automatically reversing the movement is moved back at least two character positions to facilitate reading of what has already been printed, and then is automatically moved forward by at least three character positions in the original direction with a renewed movement reversal.

A fourth drive shown in FIG. 10 includes one Frame 12 comprising a first elongated part in the form of a rod 14 of rectangular cross-section and made of magnetic Material, e.g. B. soft steel, two more elongated parts in the form of a rod 16 of rectangular cross-section and each made of magnetic material, e.g. B. soft steel, and two end plates 18, which connect the rod 14 to the rods 16. At each end of the frame 12, a bobbin 20 made of non-magnetic material is mounted on the rod 14 a wire coil 22 is wound, through which the frame 12 acts as an electromagnet.

As shown in Fig. 11, the coils 22 are over a Smoothing circuit 24 connected to a rectifier bridge 26, which receives the mains voltage of 220 V via a switch 28.

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A bobbin 46 is slidably mounted on the rod 14, on which an electrical conductor in the form of a solenoid coil 48 is wound. The bobbin 46 is with a U-shaped saddle 50 made of non-magnetic material, which is slidable on the rods 16 by means of eight pairs of rollers 52 is stored. The print head 36 is attached to the saddle 50. The fourth drive 10 includes a solenoid positioning circuit with a rigid strip 53 made of plastic, which A coil former 20 is attached at both ends to the side cheek. The stripe bears transverse lines, not shown, each of which has a width of the order of 1/10 mm and a distance corresponding to the width to the neighboring ones Has lines so that the lined and unlined portions of the strip 53 are equally wide. The strip 53 is sufficient by a housing 54 attached to the saddle 50, within which a short strip 55 of plastic is attached so that its long axis paiaLlel and at a very small distance on the order of 1/10 mm to the longitudinal axis of the strip 53. The strip 55 carries parallel lines, not shown Lines each having the same width and the same spacing as the lines on the strip 53, however are inclined by the width of a half line with respect to the normal to the longitudinal axis of the strip 55. The housing 54 also encloses a lamp 56 and two phototransistors 57 and 58, which are arranged so that the strips 53 and 55 separate the lamp 56 from the phototransistors 57 and 58. The phototransistors 57 and 58 are on opposite sides of and equidistant from the transverse axis of strips 53 and 55 arranged. The lamp 56 and the phototransistors 57 and 58 are connected to a control circuit 62 by means of a cable 60, which is the same as the control circuit 37. The control circuit 62 also has connections to the solenoid coil 48 lead, and input connections 63 for print data, via which the codes are transmitted, which are to be printed Represent characters. Furthermore, the control circuit has connections for the inputs of the print head 36. Finally, the control circuit 62 with two inputs 41 at the output

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connected to a rectifier bridge 42, which in turn is connected to the output of a transformer 44, the input of which is connected to the mains voltage of 220 V via a switch 45 receives.

The fourth drive works similarly to the third drive explained above. The relative movement between the strip 55 and the strip 53 leads to the generation of a sequence of moiré fringes, which are parallel to the longitudinal axes of the strips. 53 and 55 extend and towards the longitudinal edges of these strips travel at a speed which is different from the relative speed the strip 53 and 55 depends. The phototransistors 57 and 58 count the strips to generate a Pulse sequence in which the distance between the individual pulses equals a column distance and in which the phase the pulse train from the phototransistor 57 in relation to the pulse train from the phototransistor 58, whose pulse train serves as a basis for comparison, with the speed and direction of the movement of the solenoid 48 is related. The impulses of. Pulse train from the phototransistor 58 are not by means of a character counter circuit shown in the control circuit 62 is counted. The character counter circuit is in the counting position a start signal and causes the counting of the number of column positions between the position of the solenoid 48 and the Start signal. The pulses of the pulse train from phototransistor 58 are also divided into successive groups of seven each Pulses divided, the circuits within the control circuit 62 control so that during the first five pulses through the Print head 36 can print five columns to form a complete character while during the following two Impulse cannot be printed, leaving two / one columns of space between consecutive characters .

The speed of the solenoid 48 is controlled by means of speed control pulses kept roughly constant. The speed control pulses are generated by differentiating the pulse trains from the phototransistors 57 and 58 by means of a

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obtained circuitry not shown within the control circuit 62 which supplies current pulses to the solenoid 48. The differentiated base pulses from phototransistor 58 control the end of the solenoid current pulse and the differentiated pulses from phototransistor 57 override the normal beginning of the solenoid current pulse at approximately 700 µsec. after the end of the current pulses to affect the duration of the solenoid current pulses. The control provides feedback in that as the speed of the solenoid increases, the duration of the solenoid current pulses decreases so that the solenoid 48 receives less current, and as the speed of the solenoid 48 decreases, the duration of the current pulses increases to increase the speed of the solenoid 48 is increased again. The speed of the solenoid 48 is thus kept within two limit values in this way. The print data transmitted to the control circuit 62 include control signals, e.g. B. " ^{print start 11} ," print end "," space "," tabulation "and" carriage return ", which also control the amplitude and polarity of the DC voltage transmitted to the solenoid coil 48 and the operation of the print head 36.

The manner in which the print head 36 is mounted in the fourth drive 10 has the advantage of greater mechanical stability compared to the storage in the first and second drive.

The pressure data transmitted to the control circuit 62 can be written in any standard code, e.g. B. the ASC11 code.

The transmitted from the control circuit 62 to the solenoid coil 48 Voltages can vary in polarity and amplitude, direction or speed of the printhead 36 to control, and a pulsed duty cycle and a pulsed amplitude according to the signals "Tabulation" or have "carriage return". The control circuit 62 can bring about the automatic movement of the print head 36 as previously has been explained with reference to the control circuit 37.

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Instead of or in addition to the circuit to which the solenoid coil 32 is connected, those with the Solenoid coils 22 connected to circuits can be controlled.

The circuit for detecting the solenoid position can Photo-optical devices, magnetic devices or sliding contacts for generating the pulses, which Represent characters as column positions.

The circuit to control the power supply to the electric view Conductor can stop the movement of the electrical conductor by switching off and short-circuiting the electrical conductor Brake the conductor or by suddenly reversing the polarity of the current flowing through the conductor.

The circuit for controlling the supply of current to the electromagnet can stop the movement of the electrical conductor by reversing the polarity of the current flow through the electromagnet either alone or together with a change in the current flow brake through the electrical conductor.

The circuits for controlling the power supply to the electrical conductor and to the electromagnet can either be separated or work together to the electrical conductor without mechanical impact at both ends of its trajectory to stop.

Claims

ORIGSMAL INSPECTED 69VII

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Claims (17)

PATENT CLAIMS 1.J Drive for the print head of a printing machine, g e - characterized by a magnetic circuit (12) with at least one magnet for generating a magnetic one Field in the region of at least one elongated part (14, 16) can be displaced in the longitudinal direction of the part stored electrical conductor (32, 48), which when subjected to an electrical current under the influence of Magnetic field is movable and the print head (36) carries, and through a magnetic field and / or the current to Conductor influencing control device (40, 62) for controlling the movement of the conductor » 2. Drive according to claim 1, characterized in that g e k e η η -. draws that to generate the magnetic field at least one electromagnet (22) is provided, and that the magnetic field normal to the longitudinal direction of the elongated Part (14, 16) is aligned. 3. Drive according to claim 1 or 2, characterized in that the magnetic circuit (12) except for a first elongated part (14) has at least one further elongated part (16) which is parallel to the first part is connected, wherein the magnetic field is generated between the parts. 4th Drive according to Claim 3, characterized in that the electrical conductor (32, 48) is mounted displaceably on one of the elongated parts (14, 16). / ₉ . 409809/1001 5. Drive according to one of claims 1 to 4, characterized in that the electrical conductor (32, 48) forms a solenoid with at least one spiral winding guided around an elongated part (14, 16). 6. Drive according to one of claims 1 to 5, characterized in that a feed circuit for the conductor (32, 48) is provided which comprises a circuit for controlling the changes in the output current. 7. Drive according to one of claims 2 to 6, characterized - that a feed circuit for each electromagnet (22) is provided which comprises a circuit for controlling the changes in the output current. 8. Drive according to one of claims 2 to 7, characterized in that the control device (40, 62) comprises switching means in at least one feed circuit for the conductor (32, 48) and / or each electromagnet (22). 9. Drive according to claim 8, characterized in that the at least one of the feed circuits The polarity of the current delivered is reversible. 10. Drive according to one of claims 1 to 9, characterized in that the control device (40, 62) only affects the current to the electrical conductor (32, 48) to control its movement. 11. Drive according to one of claims 1 to 10, characterized characterized in that the control device has a circuit (53 to 58) for detecting the respective position of the electrical conductor (48) with respect to a fixed point. / 3 409809 / 10Oi 234175A 12. Drive according to claim 11, characterized in that the control device (40, 62) has a Circuitry for controlling changes in the current supplied to each solenoid (22). 13. Drive according to claim 12, characterized in that the each electromagnet (22) supplied Current can be changed independently of the current supplied to the conductor (32, 48). 14. Drive according to claim 12 or 13 »characterized in that the control device (62) in accordance with the detected position of the electrical conductor (48) the power supply to the electrical conductor and to each Affected electromagnet (22) to control the movement of the conductor. 15 · Drive according to one of claims 11 to 14, characterized characterized in that the electrical conductor (32, 48) is automatic from any point of its trajectory is traceable in a starting position. 16. Drive according to one of claims 11 to 15, characterized in that the electrical conductor (32, 48) by at least one character position after a movement the extent of which equals at least one character Can be moved to facilitate reading of what has already been printed. 17. Drive according to one of claims 11 to 16, characterized characterized in that the electrical conductor (32, 48) to an extent corresponding to at least one character position equals, is movable for printing at least one character, the movement by at least the same number of Character- ^ positions to facilitate reading of the already The print is reversible, and that the movement to print at least one other character again in the original Direction is reversible. ^69VI1 409809/1001 Blank page