JPS59187882A - Printer - Google Patents

Abstract

PURPOSE:To enhance high-speed driving characteristics at the time of returning a carriage, by a method wherein an exciting voltage higher than that for scanning in a forward direction is impressed on a stepping motor for driving a carriage, for a predetermined period of time when returning the carriage. CONSTITUTION:The stepping motor 38 for driving the carriage 31 is provided with means 61-64 for supplying a driving pulse, the first exciting voltage supplying means 65 for impressing an exciting voltage for scan printing, and the second exciting voltage supplying means 67 for impressing an exciting voltage higher than said exciting voltage when returning the carriage. Further, change- over means 68, 69 are provided for supplying the exciting voltage from the second exciting voltage supplying means 67 to the stepping motor 38 for a predetermined period of time from the moment a driving pulse is inputted into the motor 38, in accordance with the discrimination result from a means for discriminating whether or not the operation is to return the carriage.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a printer, and more particularly to a printer whose carriage is driven by a stepping motor.

Particularly in printers that print characters, such as thermal printers, Infusiera 1 printers, and Dra 1 impact printers, the carriage equipped with the print head is moved at a constant speed during printing to obtain high print quality. In addition, when the carriage returns, it must be driven at high speed for high-speed printing.

By the way, among such printers, there is one in which the carriage is driven by a stepping motor.

However, when the stepping motor is used to drive the carriage in this manner, there is a problem in that torque is insufficient in the high speed range, making it impossible to return the carriage at high speed, making it impossible to increase the printing speed.

Therefore, in order to solve the shortage of I/back in the high speed range, it is conceivable to apply a high voltage, for example, a voltage several times the rated voltage, to each excitation coil of the stepping motor when the carriage returns.

FIG. 1 is a circuit diagram showing an example of such a stepping motor drive control circuit.

This drive control circuit first sequentially excites each of the excitation coils A, A, B, and B of the stepping motor 1 with drive pulses D P and P4 through transistors 2 to 5, and then the stepping motor 1 to drive.

one motor J, each excitation coil A of the stepping motor 1,
Δ, B, +3 are supplied with a power supply voltage V (for example, +24 pol I~) that is several times the rated value, and connected to the power supply voltage V (for example, +24 pol I~), and the diode D1. D2, and 1-Randistaph and dropper resistors R1 and R2 for stepping down the voltage to the rated voltage.
control pulses SP1. through inverters 8 and 9. SP2
I am trying to control it on and off.

Therefore, during printing, the control pulse S I" is
By setting the control pulse SIN, ;, to I-1'', the 1-rangistaro is turned off and the 1-rangestaff is turned on. A stepped down rated voltage is applied.

On the other hand, when the carriage returns, the control pulse S
By setting P1 to ``H'' and control pulse SP2 to I,'', the 1 to run dial is turned on.

The h-range staff is turned off, and a power supply voltage (2) several times the rated voltage is applied to the stepping motor 1 at the tie reflex 1-.

Incidentally, when a voltage several times the rated voltage is applied to the stepping motor, the frequency -1~ruther characteristic is as shown in FIG. 2, for example. In the figure, curve I shows pull-in 1-back, and curve 2 shows pull-out torque. Furthermore, the area indicated by diagonal lines is the used area.

However, if an excitation voltage several times the rated value is constantly applied to the stepping motor during carriage return, the temperature of the motor and dropper resistor will rise significantly.
Power consumption increases.

Furthermore, when an excitation voltage several times the rated voltage is applied to the stepping motor, a large torque is generated in the low speed range, as shown in FIG.

Purpose - The present invention has been made in view of the above points, and an object of the present invention is to improve high-speed drive characteristics during carriage return in a duplex type printer.

And - precepts Hereinafter, the configuration of the present invention will be explained based on one embodiment.

FIGS. 3 and 4 are a perspective view showing the external appearance of the printer 1 and 1 embodying the present invention, and an exploded perspective view of the outer casing thereof.

In both figures, the outer casing of this printer includes a main body case 11 that houses a printing mechanism section and a printing control section, and a cover 12.
and a bottom plate 13.

FIG. 5 is a plan view showing the printing mechanism section of this printer.

In the figure, a platen 21 for winding and feeding paper to be printed is rotatably attached to a frame 2o.

This platen 21 is driven via a gear train 23 by a paper feed motor (line feed motor) 22 consisting of a stepping motor fixed to the frame 2o.
Automatically feeds paper.

Further, the platen 21 has knobs 24 and 25 fixed to both ends thereof, and can be manually rotated by turning the knobs 24 and 25 when loading or removing paper.

Note that rotatable rollers 2G and 27 are brought into pressure contact with this platen 21 in order to push the paper onto the surface.

The carriage 61 is mounted on the rond 28 and the stay 2B fixed to the frame 20 so as to be movable parallel to the platen 21 in its axial direction.

The carriage 31 includes a print head 33 on a carrier frame 32, a solenoid 34 for driving the print head 33, ribbon masks 65 and 36, and the like.

This carriage 61 is driven by a space motor B consisting of a 4-phase steppin motor mounted on the frame 20, and a timing roller 3 fixed to its rotating shaft 38a and a reel rotation of the ribbon case 40 mounted on the frame 20. It is driven via a timing bell 1-43 fixed to the lower part of the carriage 31.

The ink ribbon 44 wound around the reels 40a and 40b of the ribbon case 40 is passed between the ribbon mask filters 5 and 36 of the carriage 31 between four hooks 45 to 48 attached to the frame 20, and mounted on the platen 21. and the print head 33, and the running direction U (not shown) is
'! The 'I mechanism allows the carriage 'z31 to travel when the space motor 68 moves forward and backward.

FIG. 6 is a block diagram showing an example of a control section of this printer.

In the figure, it is a block diagram of the printer controller 1 to the roll circuit 51.

In the same figure, a printer control circuit 51 is a circuit that also serves as a determination means and controls the entire printer, and includes a CPU (central processing unit), a programmer 11 memory (
It is composed of a microcomputer consisting of a data memory (RAM), an input/output device (]'10), etc.

This printer controller 1-roll circuit 51 receives print data and space data from the host system 11 side of a computer, word processor, etc. via a printer interface circuit 52 consisting of a blockrammable communication interface or the like.

Various data such as line feed data and carriage return data are transferred.

Based on the processing results of various input data, this printer controller 1-roll circuit 51 first generates a tarok pulse CLK for generating drive pulses to specify the print position, and a rotation pulse CLK for specifying the rotation direction. Direction designation pulse L) JR, l-Phase excitation designation pulse P T for designating either 2-phase excitation control or 2-phase excitation control
-I C, outputs a high voltage application command pulse HPS to the drive control circuit 53 to command the application of high voltage at the time of carriage return, etc. to drive and control the space motor 38;
Positioning the carriage 31 at a predetermined position.

Incidentally, the ROM of this printer controller 1-roll circuit 51 stores a speed table corresponding to a speed pattern for generating the clock pulse CLK for (2)-2 phase excitation control.

Further, for printing, the printer control circuit 51 outputs a drive pulse DH to the driver circuit 54 to drive and control the solenoid 34, and selectively drives each print button of the print head 66. Since the details are well known, their explanation will be omitted.

Further, the printer control circuit 51 outputs a drive pulse DL to the driver circuit 55 to drive and control the line feed data 22 to rotate the platen 21 for line feed.

Incidentally, the rotation of the space motor 38 and detection pulses from a sensor for detecting the home position, as well as detection pulses from a cover oven switch and a paper detection switch (not shown) are also input to the roll circuit 51 to the printer controller 1.

Next, the I! of this control section! The outline of the 1i2WJJ control circuit 56 will first be explained with reference to FIG.

In the same figure, the 1-2 phase excitation control circuit 61 inputs the 1-2 phase excitation control clock pulse CLK and the rotation direction designation pulse DIR from the printer controller 1-roll circuit 51 to control the space motor 68 in the 1-2 phase. Drive pulses DPA, ~DP to rotate in the specified rotation direction by phase excitation
At the same time as outputting A4, its drive pulse DPA, ~
I) I) Timing pulse at each output of A4
' I) Output A.

The 24CI excitation control circuit 62 receives the 1-2 phase excitation control clock pulse CL' from the printer control circuit 51.
Input K and rotation direction designation pulse DIR,
It generates clock pulses for phase excitation control and outputs drive pulses DPB1 to DPB for rotationally driving the space motor 38 in a designated rotational direction with two-phase excitation, and the drive pulses ■]PB1 to DPB134. A timing pulse TPB is output at the time of output and at the start of carriage return.

Note that both of the 1-2 phase excitation control circuit 61 and the 2-phase excitation control circuit 62 are drive pulse generating means.

The switching circuit 63 inputs the phase excitation designation pulse I)IIG from the printer control circuit 51, and changes the drive pulse DpA, ~I from the 1-2 phase excitation control circuit 61 according to the designated phase excitation. ) P A Drive pulse DPB from 4 or 2-phase excitation control circuit 62, ~DPB
4 is selected and outputted to the driver circuit 64 as drive pulses DPz to DP4.

Driver times i! 864 is Dora R Bubarsu DP1~D
Each excitation coil of the space motor 68 is excited in accordance with P4.

On the other hand, the low voltage power supply 65 is a first excitation voltage applying means, and applies the first excitation voltage
1 is applied to the space motor 38.

The high voltage power supply 67 is a second excitation voltage applying means, and a switching circuit S8 connects and disconnects the power supply path according to an external command.
A second excitation voltage V 2 (V 1 < V 2 ) higher than the first excitation voltage V 1 is applied to the space motor 38 via the space motor 38 .

The switching control circuit 6S includes printer controller 1 to roll circuit 51.
Phase excitation designation pulse P HC from and high voltage application command pulse HP is input, and the switching circuit 68 is controlled according to the input result, so that while the high voltage application command pulse HP S is input, the phase excitation designation pulse P
A switching pulse CP is output for connecting the power supply path from the high voltage power supply 67 to the space motor 68 for a predetermined time from when the timing pulse T PΔ or the timing pulse l' P B is input in accordance with the HC.

Note that the switching circuit 6 and the switching control circuit 6S constitute a switching means.

Next, an example of a specific configuration of this drive control circuit 53 will be explained in the seventh section.
This will be explained with reference to the figures.

In the figure, the 1-2 phase excitation control circuit 61 includes a shift register 71. Inverter circuit 72~76° AND circuit 7
7 to 80 and OR circuits 81 and 82.

The shift register 71 has mode control l-roll terminals SO, SL, a clock terminal CK, a shift right serial input terminal SR, a shift reflex 1-serial input terminal SL, output terminals QA-QD, etc., and the terminal SO is゛'
When the terminal S1 is "H" and the terminal S1 is "L", a right shift is selected, and when the opposite is true, a left shift is selected.

A rotation direction specifying pulse DIR is directly input to the terminal SO of the shift register 71 via an inverter circuit 72, and a rotation direction specifying pulse DIR is input directly to the terminal S1, and a tarokk pulse CLK is input to the clock terminal GK via the inverter circuits 8 and 84. are doing.

Then, the QA output and QB small output of this shift register 71 are directly input to the circuit 77 and the drive pulse D
I) A is input to the AND circuit 78 via the inverter circuits 73 and 74 to generate the drive pulse DPA2, and the QC output and Q'D output are directly input to the AND circuit 7 to generate the drive pulse DPA3. , are input to an AND circuit 80 via inverter circuits 75 and 76 to generate drive pulse DPA4.

Also, the drive pulse D from the AND circuits 77 and 78
PA and DPA2 are input to the OR circuit 81 to generate the timing pulse T P A I , and drive pulses DPAa and DPA from the AND circuits 7B and 80 are input to the OR circuit 82 to generate the timing pulse TPA2.

The two-phase excitation control circuit 62 is a D-type flip-flop circuit (
(hereinafter referred to as rD-FFJ) 85-87° NAND circuit 88
and exclusive OR circuits 89-92.

First, by the D-FF circuit 85 and the NAND circuit 88,
Clock pulses are generated by dividing the clock pulses C and LK inputted through the inverter circuits 83 and 84 into 1/2.

Then, from this clock pulse, a drive pulse DPB and DPB2 are generated by a D-FF circuit 86 and an exclusive OR circuit 8 which inputs a pulse obtained by inverting the rotation direction designation pulse DIR by an inverter circuit 72. The D-'FFuFF circuit 86 generates drive pulses DPB3 and DPB4 by an exclusive OR circuit SO to which a pulse obtained by inverting the rotation direction designation pulse DIR by the inverter circuit 72 is input.

Further, the drive pulse D P B s which is the Q output of this D-FF circuit 86 and the drive pulse D P B 4 which is the Q output of the D-FF circuit 87 are inputted to the exclusive OR circuit 91, and this Shibuor circuit 9
A pulse obtained by inverting the output of No. 1 and the rotation direction designation pulse DIR by an inverter circuit 72 is input to the exclusive OR circuit S2 to generate a timing pulse TAB.

Here, 1-2 phase excitation of the 4-phase stepping motor
Table 2 Table 1 shows the magnetic force equation, and Table 2 shows the binary dynamic magnetic force equation. In addition, A, A, B in the picture table.

The stones represent excitation coils, ○ means energized state, and × means non-excited state.

■-The two-phase excitation control circuit 61 and the two-phase excitation control circuit 62 use the drive pulse D according to these Tables 1 and 2.
P A 1-D)) A, and D P I31-DPB
Outputs 4.

Note that the drive pulses DPA1 and DPB+ are for exciting coil A, and the drive pulses I)PA2. DPB2 is for exciting coil A, drive pulse DPA3゜DPB3 is for exciting coil B, drive pulse DPA4, D P B4
is for excitation coil) 1.

The switching circuit 63 is a known data selector, and selects drive pulses DPA1 to DI'A4 or input terminal B1 which are input to the input terminals Δ1 to A4 according to the phase excitation designating pulse PHC which is input to the selenium 1 terminal SE. - Drive pulse DPB input to B4.

~DPB4 are output as drive pulses DPI~DP4 from output terminals ¥1~Y4.

Note that this switching circuit 63 selects the input terminals A1 to Δ4 when the select terminal SE is L'', and selects the input terminal B when the select terminal SE is II''.
Select l~B4.

The driver circuit 64 includes excitation control transistors 96 to 9.
drive pulse 1. ) P, ~1 each excitation coil A, A, B, B of the space motor 8 according to P4
control the excitation of

The correction circuit 66 includes a resistor 103 for torque balance adjustment inserted in series in a power supply path from the low voltage power supply 65 to each excitation coil A, A, B, B of the space knee 138. Rise characteristics of excitation current] Consists of three circuits of resistors 104 and 105 and diodes 106 and 107.

The switching circuit 68 connects the high voltage power supply 67 to the space motor 3.
A transistor 110 inserted in the power supply path to the excitation coils A and A of No. 8. It consists of a transistor 111, inverter circuits 112, 113, etc. inserted in the power supply path from the high constant voltage electric @67 to the excitation coils I3, 13 of the space motor 38, and the power supply path is connected when the external pulse is I-1''.

The switching control circuit 6 consists of a data selector 115°, a dual switch 1, a helicopter pulley, a one-shot 1 to a multi 116, and an inverter circuit 117.

The data selector 115 selects the selector 1 from the input terminal A in response to the phase excitation designation pulse PHC input to the terminal SE.
1, timing pulse TPA input to A2, , 'TPA2 or input terminal B1. , B2 directly or via the inverter circuit 117 is input to the output terminal Yl.

Output from ¥2.

Note that this data selector 115 has a select terminal SE.
When is L'', input terminals A], A2 are selected as I-('', input terminals Bl and B2 are selected.

One shock 1 to multi 116 are high voltage application specified pulse H
Output terminals Yl, 'Y2 of PS and data selector 115
When both are at H'', switching pulses CPI and CP2 having a predetermined pulse width, for example, 0-8 m5ec, are output to the switching circuit 68.

Note that the 1-2 phase excitation control circuit 61 and 2-phase excitation control circuit 62 of the drive control circuit 53 (FIG. 6) may be constituted by a microcomputer together with the printer controller 1-roll circuit 51.

Next, we will discuss the effects of the embodiment configured as described above.
The explanation will be given with reference to the following figures.

FIG. 8 is a flow diagram showing an overview of printer control executed by the roll circuit 51 to the printer controller 1. As shown in FIG.

In the figure, after the power is turned on, the printer control circuit 51 executes operations 1 to 1, such as positioning the carriage 31 at the Baum position.

Then, the data transferred from the host system side is read from the buffer memory, and if the data is character data, the print needle drive solenoid 64 of the print head 3B is controlled to print the character.

Also, if the data is space data, the carriage 31 is moved by one character (space), if it is line feed data, the platen 21 is rotated by one digit (line feed), and if the data is carriage return data, the carriage 61 is moved to the home position. Return to position (carriage return). (9) Carriage return operation may also be performed using line feed data.

FIG. 9 is a flow diagram showing an example of the control operation of the drive control circuit 56 executed by the printer control circuit 51.

In the same figure, printer con! - The roll circuit 51 performs a printing operation (print data and space data) when the data from the host system is data that involves movement of the carriage 31, such as print data, space data, and carriage return data. processing operation).

If the result of this determination is a printing operation, the drive control circuit 56 sends a phase excitation designation pulse P tlC for selecting 1-2 phase excitation.
Output to.

As a result, the switching circuit 63 of the drive control circuit 53 switches from 1 to
Drive pulse D output from the two-phase excitation control circuit 61
PAI~D 11 A,, drive pulse DP,~
The switching circuit 68 becomes connected (on state) at the input timing of the timing pulse T PΔ from the two-phase excitation control circuit 61. A state is entered in which a switching pulse CP is output.

The roll circuit 51 to the printer controller 1 outputs a tarok pulse Or-r<- and a rotation direction designation pulse DIR.

High voltage application command pulses T (PS) are output in a predetermined order to drive and control the space motor 38 under 1-2 phase excitation control.

On the other hand, if the determination result is not a printing operation, it is determined whether or not it is a carriage return operation, and if it is a carriage return operation, the phase excitation pulse P selects two-phase excitation control.
Outputs HC to drive control circuit 5.

Thereby, the switching circuit 63 of the drive control circuit 53 switches between drive pulses DPB output from the two-phase excitation control circuit 62.
, ~DPB4 are output to the driver circuit 64 as drive pulses DP, ~DP, and the switching control circuit 6
Timing pulse 'I' from the two-phase excitation control circuit 62
” At the input timing of PB, a switching pulse CP is output that puts the switching circuit 68 in a connected state (on state).

The printer controller 1-roll circuit 51 receives a tarok pulse CLK and a rotation direction designation pulse 1DIR.

High voltage application command pulses 1-JPS are outputted in a predetermined order to drive and control the space motor filter 8 under two-phase excitation control.

In this manner, the space motor is driven using 1-2 phase excitation control during printing operations that require constant speed 11g movement, and is driven using dual sum excitation control during carriage return that requires high-speed drive.

As a result, there is less vibration during 1-2 phase excitation compared to 2-phase excitation, which improves the uniformity of printing operation, and when the tarok pulse or drive pulse is generated by a microcomputer, When using 2-phase excitation, the pulse interval is twice as long as when using 1-2 phase excitation, so the limit value of the pulse generation interval due to the processing time constraints of the microcomputer becomes higher, and the high speed during high-speed driving is reduced. improves.

FIG. 10 is a flow diagram showing a subroutine of the 1-2 sum excitation control in FIG. 9.

In the figure, the printer controller 1-roll circuit 51 first moves the space motor 38 in the direction in which the carriage 31 moves forward.
A rotation direction designation pulse D of 1 length for dazzling is outputted to the drive control circuit 53 to set the rotation direction.

Then, after starting the drive of the space motor rotor 8, when the acceleration is finished, check whether F1=O is F1=0 or not, and FI=
If it is O, it outputs the high voltage application command pulse 11PS, and if it is not F1, it outputs the L1 pulse CLK.

Thereafter, it is checked whether the acceleration has ended or not, and when the acceleration has ended, the output of the high voltage application command pulse I-T PS is stopped and the flag F1 is set to 1 ~ 1''), until the acceleration is not completed. returns to the main routine.

By the printer controller 1-roll circuit 51 executing such control, the drive control circuit 53
The phase excitation control circuit 61 generates drive pulses DI) A, ~D at the timing when the blackout pulse CLK is input.
P A4 is output to drive and control the space motor 38 using 1-2 phase excitation control.

At the same time, the switching control circuit 69 outputs a timing pulse TPA from the 1-2 phase excitation control circuit 61 when the high voltage command pulse I-(PS) is input to the star 1 and during acceleration.
is input ■, Y, Zunai drive pulse ■ P
When A is output, a predetermined pulse width (for example, 0.8 m
A switching pulse CI] with a pulse width of 5 ec) is output.

As a result, the switching circuit 68 is activated for a predetermined time (for example, 0.8
m5ec), connect the power supply path from the high voltage power supply 67 to the space motor Otsu 8.

Therefore, as shown in FIG. 11, each excitation coil Δ, i B + 13 of the space motor 38 has a timing pulse 1 at the start of rotation (Star 1~) and during acceleration.
A high voltage 2 is applied from the high voltage power supply 67 for a predetermined period from the time of excitation A, after the predetermined time has elapsed and after the end of acceleration (at constant speed). Only the low voltage v1 from the low voltage power supply 65 is applied.

By controlling the drive in this manner, the star 1 characteristics of the carriage can be improved without impairing uniform velocity.

FIG. 12 is a flow diagram showing a subroutine of two-phase excitation control in FIG. 9.

In the figure, the printer controller 1-roll circuit 51c, the space motor 38 in the direction in which the mass carriage roller 1 moves backwards.
A rotation direction specifying pulse DIR for rotating the cylinder is output to the drive control circuit 56 to set the rotation direction to the cylinder 1.

Then, set it after a certain period of time has passed ( ” ] ”
) Check whether flag F2 is F2-o or not, and if F2=Q, start the timer by setting it to zero.
When the timer completes the time amplification, the flag F2 is set to Sera 1 and then the high voltage application command 1-1 ■l S is output and F
If 2 is not 0, immediately after outputting the high voltage application command HP S, the tarok pulses C1 and -K are output and the process returns to the main routine.

When the printer control circuit 51 executes such control, the drive control circuit 53 generates a clock pulse in which the two-phase excitation control circuit 62 divides the clock pulse CLK by 1/2, and uses this clock pulse as a clock pulse. Accordingly, drive pulses DPB1 to DPB,l are output to drive the space motor 38 under two-phase excitation control.

At the same time, the timing pulse TP is applied when the high voltage application command pulse IPS is input when the switching circuit 69 starts the carriage return and when the carriage returns thereafter.
When B is input, that is, when drive pulse DPB is output, a switching pulse CP is output to the switching circuit 68.

Thereby, the switching circuit 68 connects the power supply path from the high voltage power supply 67 to the space motor "" 38 for a predetermined time.

Therefore, as shown in FIG.
A high voltage V2 is applied from the high voltage power supply 67 to each of the excitation coils A, A, , B, and B for a predetermined period of time from the time when the carriage return is started and when the excitation coils are excited by the timing pulses DPBI to DPB4 at the time of the carriage return. , thereafter, low voltage (1) is applied from the low voltage power supply 65.

In this manner, by applying the quotient excitation voltage for a predetermined period of time at the beginning of the carriage return, the auxiliary start characteristics at the time of carriage return are improved.

In addition, by applying a high excitation voltage for a predetermined period of time when the carriage returns, high torque can be obtained in the high-speed range without increasing the temperature of the motor or increasing power consumption.
High-speed return of the carriage is possible.

Furthermore, as shown by the broken line in FIG. 13, it is effective to prevent synchronization if a high excitation voltage is applied even during a pause after the end of the printing operation until the start of carriage return.

Incidentally, FIG. 14 shows an example of the frequency-torque characteristic of the motor when drive control is performed such that a high excitation voltage is applied for a predetermined period of time. In the figure, the curve (■) indicates the pull-in torque, and the curve (2) indicates the pull-out 1-lux. Furthermore, the area indicated by diagonal lines is the used area.

As is clear from Fig. 14 and Fig. 2 shown earlier, the increase in 1-rook in the low speed range is suppressed and becomes flat, and the necessary torque is obtained. The frequency range that can be detected is getting higher.

Furthermore, since a capacitor is used to process the back electromotive force (see Figure 7), the high range is further extended.

Next, regarding the action of the correction circuit 66, the 15th @ and 16th
This will be explained with reference to the figures.

First, generally speaking, the excitation coil φ of each phase of a chipping motor is
The relationship between the static torque generated by 1 to φ4 and the rotation angle is approximately sinusoidal, as shown in FIG. 15, for example.

As can be seen from the figure, the torque is different between one-phase excitation and two-phase excitation when the applied excitation voltage (or excitation current) is kept constant.

That is, when the rotation angle of the motor is 0, the exciting coil φ1
If one herter is racosO, then the exciting coil φ
The torque due to
(0+π/4). In other words, the torque generated during two-phase excitation is five times the 1-rook generated during one-phase excitation.

Therefore, the stamping motor is controlled by a constant excitation current (
or voltage) is applied and controlled by 1-2 phase excitation,
As shown by the curve I (thick line) in FIG. 16, the generated 1-lurk differs between one-phase excitation and two-phase excitation.

Therefore, when the space motor is controlled by 1-2 phase excitation during the printing operation as described above, vibrations still occur, although the vibrations are smaller than when controlled by dual sum excitation.

Therefore, in this embodiment, the current flowing through the exciting coil during 1-2 phase excitation and the current flowing through the exciting coil during 2-phase excitation are changed by the correction circuit Wi't 66, so that the generated torque is approximately the same. I'm trying to make it happen.

In other words, the I-lux generated during one-phase excitation is 1゛].

Assuming that 1~rook generated during two-phase excitation is T2, there is a relationship of T I = T 2 /H as described above, and the torque is approximately proportional to the excitation current.

Therefore, if the current flowing through the excitation coil during one-phase excitation is 1, and the current flowing through the excitation coil during two-phase excitation is 12, then 1s = 5I2, then 1-ruk generated during one-phase excitation is as shown in Figure 16. is shown by the curve ■ (imaginary line), and if ■2-■1/, Ti, the torque generated during two-phase excitation is shown by the curve ■ (dashed line) in the same figure. Approximately the same torque is generated in one-phase excitation and two-phase excitation.

As a result, torque ripple during 1-2 phase excitation is extremely reduced, and vibration is reduced.

In addition, when the correction circuit 66 is configured as shown in FIG. 7, the resistance value of the resistor 103 is R1, the resistance value - of the resistors 104 and 105 is R2, and each exciting coil A, A.

If the resistance value of the internal resistance of B and B is r, then for example R1=
By establishing the relationship (r + R2)/5, the torques generated during one-phase excitation and during two-phase excitation can be made approximately the same.

The configuration of the correction circuit 66 is not limited to that shown in FIG. 7, but may be configured as shown in FIG. 17, for example.

The correction circuit 6 shown in the same figure converts the low voltage 1 from the low voltage power supply 65 into 1 Herc balance resistor 103 and diode 1.
-120, and the excitation coils Δ, C or B, B are supplied with power via the resistor 104 or 105.

In this case, for example, transistors 1 to 110 are turned on and a high voltage v2 is applied to the excitation coil A.

When power is supplied to A, the current ■ flows through resistance 1 as shown by the dashed arrow.
The current also flows into the exciting coils B and B via 04 and 105, and the torque characteristics are affected by the current change at this time.

Next, an embodiment will be described in which the printer control circuit 51 shown in FIG. 6 generates tarock pulses for -2 phase excitation control and dual sum excitation control.

In this case, the printer controller 1-roll circuit 51 (7)
A speed table corresponding to a speed pattern for generating tarock pulses for two-phase excitation control is stored in the ROM.

Then, during two-phase excitation control, a tarlock pulse CLK2 is generated according to the speed table in the ROM.

During 1-2 phase excitation control, set the value of the ROM speed table to 1.
/2 and then adjust the tarokk pulse CLK according to the result.
Generates 1.

When configured in this way, the printer control circuit 5
FIG. 18 shows an example of the drive control operation of the space motor executed by No. 1.

Also, an example of the relationship between the clock pulse CLKI and the excitation state of each excitation coil during 1-2 phase excitation control is shown in FIG.
An example of the relationship between the clock pulse CL K 2 and the excitation state of each coil during two-phase excitation control is shown in FIG. 20, respectively.

As can be seen from both figures, when the pulse interval of the clock pulse CLK1 is tn (n=1...n), the pulse interval of the clock pulse CLK2 is 2tn (n-1...n). That is, the clock pulse CL K 1 is generated at half the pulse interval of the clock pulses CI-, K 2 .

In this way, by sharing the speed table for generating the clock pulses for 1-2 phase excitation control and the speed table for generating the clock pulses for 2-phase excitation control, it is possible to save more space in the ROM than when each is provided separately. Small capacity is fine.

Incidentally, in the second embodiment, an example of a printer having a printer 1 and an printer 1 is described, but it goes without saying that the present invention can be implemented in the same manner with other printers.

As described above, according to the present invention, the high-speed drive characteristics at the time of carriage return in a printer in which the carriage is driven by a stepping motor are improved.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an example of a conventional stepping motor drive control circuit, and Fig. 2 is a line showing an example of frequency-torque characteristics when the stepping motor is drive-controlled by the drive control circuit shown in Fig. 1. Figures 3 and 4 are an external view and an exploded perspective view of the outer casing of a Ton 1 to Invac 1 printer embodying the present invention, and Figure 5 similarly shows an example of its printing mechanism. 6 is a block diagram showing an example of the control section, FIG. 7 is a circuit diagram showing an example of a specific configuration of the drive control circuit shown in FIG. 6, and FIG. 8 is a block diagram showing an example of the drive control circuit shown in FIG. 10 is a flowchart showing an overview of the printer control operation executed by the printer controller 1-roll circuit of FIG. This figure is a flowchart showing an example of the subroutine of the 1-2 phase excitation control in FIG. A flowchart showing an example of a subroutine of phase excitation control; Fig. 1 is a timing chart for explaining Fig. 12; Fig. 14 is a frequency-torque diagram of the stepping motor when the control shown in Fig. 12 is executed. 15 and 16 are diagrams showing an example of the characteristics, and FIGS. 18 is a circuit diagram showing another example of the correction circuit of FIG. 6, and FIG. 18 is a flow diagram showing another example of the space motor drive control operation executed by the printer controller 1 to roll circuit of FIG. 6. , FIG. 19 and FIG. 20 are timing charts 1-- for explaining FIG. 18. Ro1... Carriage Ro8... Space motor 5
1 - Printer controller 1 to roll circuit 53... Drive control circuit 65... Low voltage power supply 67...
High voltage power supply 68...Switching circuit 6 days...Switching control circuit Figure 8 Figure 9 Figure 10 ω l< HIn 1st
Figure 2 (fX1'I< IQ) Figure 14 Figure 15 Figure 17

Claims (1)

[Claims] 1. In a printer in which a carriage is driven by a stepping motor, a first excitation voltage applying means applies a first excitation voltage to the stepping motor, and a second excitation voltage higher than the first excitation voltage is applied to the stepping motor. a second excitation voltage applying means for applying, a driving pulse generating means for outputting a driving pulse to the stepping motor, and a determining means for determining whether or not it is a carriage return time;
A second excitation voltage is applied to the stepping motor from the second excitation voltage application means for a predetermined time from when the drive pulse generation means outputs the drive pulse during carriage return according to the determination result of the determination means. A printer characterized in that it is provided with a switching means.