JP3231500B2 - Print head carrier movement control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head carrier movement control device, and more particularly to a print head carrier movement control device for a serial printer having a large inertia load and capable of operating at high speed.

[0002]

2. Description of the Related Art Conventionally, the movement of a print head carrier of a printer is performed by connecting a motor and a carrier by a power transmission mechanism such as a wire or a timing belt and converting a rotational motion of the motor into a linear motion of the carrier. ing. However, a serial impact printer capable of high-speed printing has a heavy print head, and the acceleration / deceleration distance of the carrier tends to be short due to a demand for downsizing of the device. Therefore, when the carrier is accelerated or decelerated, the vibration of the power transmission mechanism propagates to the carrier, and the vibration of the carrier continues for a while even after the carrier reaches the target speed, resulting in a decrease in print quality.

Conventionally, as a first example of suppressing such vibrations and obtaining high printing quality, a method of directly detecting a carrier moving speed by a linear scale sensor (Japanese Patent Laid-Open No. 1-2342).
No. 80) or a method of indirectly detecting the amount of expansion and contraction of a power transmission mechanism by attaching a speed sensor to both a motor-side pulley and a driven-side pulley (Japanese Patent Laid-Open No. 1-238974). It is common to use a carrier movement control device constituting a system.

FIG. 16 is a block diagram showing a second example of the related art for suppressing such vibrations and obtaining high printing quality. FIG.
In this conventional carrier movement control device, an encoder 95 is configured such that a motor 94 and a carrier 92 on which a print head 91 is mounted are connected by a power transmission mechanism 98 via a power pulley 96 and a driven pulley 97. The rotational speed y of the motor 94 of the carrier moving mechanism 9 is detected. The encoder 95 is composed of, for example, a rotary encoder that generates a two-phase signal having a 90 ° phase shift. The print head 91 is connected to the platen 9 via an ink ribbon (not shown).
3 is printed on a sheet (not shown).

The control unit 110 includes a high stability reference oscillator 111
And the encoder 95 which is the rotation speed y of the motor 94
A method using phase locked loop (hereinafter, abbreviated as PLL) control for synchronizing the phase of the output pulse signal with the phase lock signal is used.
The phase comparator 112 compares the phase difference between the motor rotation speed y, which is the output signal of the encoder 95, and the output of the reference oscillator 111, and outputs an error signal 116. The error signal 116 passes through a low-pass filter 113 having an amplifying function, and the driving circuit 1
The motor 94 is driven via the motor 14. Here the motor 94
Rotates according to the voltage of the error signal 116, and the encoder 95 generates a frequency corresponding to the rotation speed, so that the motor 94 and the encoder 95 operate as a voltage-controlled oscillator.

In the case of the PLL control, the carrier speed fluctuation in the steady state depends on the stability of the oscillator used. However, a wide capture range W is required for PLL control in order to accelerate a carrier composed of an undesired load from a stopped state over a short distance. The capture range W is a width from a frequency at which the PLL control is not locked to a frequency at which the PLL control is locked. The loop gain of the PLL control is K, and the transfer function of the low-pass filter is F (jω) (where, ω: motor rotation Assuming angular velocity, j: imaginary unit, W ≒ K · | F (j
ω) | S. This is known as an approximate expression of Moschytz. If the loop gain K is increased to widen the capture range W, the closed loop becomes unstable and oscillation may occur. Third to solve this problem
As an example, there is a method of improving the gain of the low-pass filter 113 in a high frequency range by inserting a differentiating circuit 115 in a closed loop as in the example of US Pat. No. 4,457,639 shown in FIG.

[0007]

A first example of this conventional print head carrier movement control device is expensive because of a linear scale sensor and a speed sensor attached to both a pulley on the motor side and a pulley on the driven side. Therefore, mounting accuracy is required when mounting on a device.

A third example is a low-pass filter 113
Since an analog circuit is used for the differentiating circuit 115, the capture range W depends on the accuracy of the resistors and capacitors used, and is easily affected by variations between devices. Furthermore, the differentiating circuit 115, which must compensate for heavy inertial loads, is susceptible to noise. In addition, if the reference oscillator 111 is broken and oscillation stops, the phase comparator 112 generates a very large phase error signal 116, and the motor 94 driven by the signal 116 runs away. In this example, since the position of the carrier 92, that is, the motor rotation angle information is not used, when the carrier 92 is stopped, it is not determined where the carrier 92 stops. In the worst case, the carrier 92 collides with the frame of the mechanism. I will.

[0009]

A printhead carrier movement control device according to the present invention is an encoder in which a carrier having a printhead mounted thereon is connected to a motor via a power transmission mechanism, and outputs a rotation signal of the motor. A speed detection unit that generates a rotation speed value and a rotation direction of the motor from the rotation signal; an angle detection unit that generates a rotation angle value of the motor from the rotation signal; and a target indicating a target stop angle of the motor. a velocity profile generator for outputting an angle value and the rotation angle value plurality of setting <br/> constant speed value and a sequentially controlling the speed control driving voltage to approximate the rotational speed value to the set speed value A speed control unit; an angle control unit that controls an angle control drive voltage value to bring the motor closer to the target angle value based on the rotation speed value and the rotation angle value; The speed control drive voltage value or the angle control drive voltage value may be defined as a motor drive voltage value depending on the case where the speed value and the rotation angle value are within a first predetermined speed range or a second predetermined speed range and a predetermined angle range, respectively. A speed / angle comparison unit for outputting or stopping the output, a pulse width modulation unit for generating forward and reverse rotation motor drive pulses from the motor drive voltage value and the rotation direction, and a forward and reverse rotation motor drive pulse And a power amplifying unit that supplies motor drive power to the motor based on the print head carrier movement control device.
The degree control unit calculates a speed between the set speed value and the rotation speed value.
A subtracter for calculating the error, and a gain multiplied by the speed error.
A speed integration amplifier that integrates from the time point
From the dynamic voltage value and the rotation speed value, the carrier speed and the dynamic speed are calculated.
A state estimation mechanism for estimating the amount of expansion and contraction of the force transmission mechanism;
Each of the rotation speed value, the carrier speed, and the expansion / contraction amount
A gain is multiplied and added to the output of the speed integrating amplifier to obtain the speed.
And a state feedback mechanism for setting a degree control drive voltage value .

Further, in the print head carrier movement control device according to the present invention, the speed profile generation section sequentially stores a set rotation angle value of the motor and outputs the set rotation angle value as a set angle value; Receives the angle coincidence signal, an angle comparison unit that outputs an angle coincidence signal when the angle coincides with the set angle value, a speed setting register that sequentially stores the set rotational speed value of the motor and outputs it as a set speed value, and A speed profile control unit that outputs the set rotation angle value and the set rotation speed value generated from the target angle value indicating the target stop angle of the motor each time.

[0011]

Further, in the print head carrier movement control device according to the present invention, the state estimating mechanism may be configured such that the rotation speed value, the carrier speed, the expansion / contraction amount, the speed control drive voltage value, and the rotation speed value at a certain time are included. The rotation speed value, the carrier speed, and the expansion / contraction amount at the next time are estimated from the sum of the products of the coefficients.

Further, in the print head carrier movement control device according to the present invention, the angle control section includes a subtractor for calculating an angle error between the target angle value and the rotation angle value, and integrates the angle error from an initial time. A value obtained by multiplying a predetermined first coefficient, a value obtained by multiplying the rotation angle value by a predetermined second coefficient, and a value obtained by multiplying the rotation speed value by a predetermined third coefficient value are added as the angle control drive voltage value. And an adder for outputting.

Further, in the print head carrier movement control device according to the present invention, the speed / angle comparing section sets the speed control drive voltage value to the first speed speed value until the rotation speed value falls within a first predetermined speed range. A speed comparator that outputs the angle control drive voltage value as a control drive voltage value when the speed falls within a predetermined speed range, and a second predetermined speed, wherein the rotation speed value and the rotation angle value are each smaller than the first predetermined speed range. A speed angle that stops outputting the control drive voltage value as the motor drive voltage value when the speed falls within a speed range and a predetermined angle range, and outputs the control drive voltage value as the motor drive voltage value otherwise. A comparator.

Further, in the print head carrier movement control device according to the present invention, the pulse width modulation section includes a drive voltage value setting register for storing the motor drive voltage value, a high speed clock counter for counting the high speed clock, A drive voltage comparator for comparing the output of the drive voltage value setting register with the output of the high-speed clock counter and outputting a drive voltage match signal; and a high-speed clock for dividing the high-speed clock and outputting a high-speed clock divided signal A frequency divider; an RS flip-flop for outputting the motor drive pulse using the high-speed clock frequency-divided signal as a set signal and the drive voltage coincidence signal as a reset signal; and outputting the motor drive pulse based on the rotation direction. A drive pulse and a selector for selecting and outputting as the reverse rotation motor drive pulse.

Further, in the print head carrier movement control device of the present invention, the power amplifying unit includes four bridge-shaped transistors having one end connected to the power supply and the other end connected to the motor.

[0017]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.
Referring to FIG. 1, in the print head carrier movement control device of this embodiment, an encoder 95 includes a print head 91.
And a motor 94 connected to the carrier 92 by a power transmission mechanism 98 to output rotation signals SN1, SN2 of the motor 94 of the carrier moving mechanism 9. The speed detector 2 generates a rotation speed value SN4 and a rotation direction SN5 of the motor 94 from the rotation signals SN1 and SN2. The angle detector 3 outputs the rotation signal SN
A rotation angle value SN6 of the motor 94 is generated from 1 and 2.
The speed profile generator 1 outputs a set speed value SN12 from the target angle value SN13 indicating the target stop angle of the motor 94 and the rotation angle value SN6. The speed control unit 4 controls the speed control drive voltage value SN7 to bring the rotation speed value SN4 closer to the set speed value SN12. The angle control unit 5 uses the rotation speed value SN4 and the rotation angle value SN6 to control the motor 94 to approach the target angle value SN13.
Control N8. The speed angle comparison unit 8 has a rotation speed value SN4
And when the rotation angle value SN6 falls within the predetermined speed range εs or εv and the predetermined angle range εx, respectively, depending on the case, the speed control drive voltage value SN7 or the angle control drive voltage value SN
8 is output as the motor drive voltage value SN9 or the output is stopped. The pulse width modulation unit 6 has a motor drive voltage value S
Forward rotation and reverse rotation motor drive pulses SN10 and SN11 are generated from N9 and the rotation direction SN5. The power amplifier 7 supplies motor drive power to the motor 94 based on the forward and reverse motor drive pulses SN10 and SN11.

FIG. 2 is an operation time chart of the speed detector 2 and the angle detector 3 of this embodiment. Referring to FIG. 1 and FIG. 2, two-phase rotation signals SN1 and SN2 with a 90 ° phase shift output from encoder 95 are input to speed detection unit 2 and angle detection unit 3, respectively. The speed detector 2 detects the pulse width of the rotation signal SN1 by using the clock generator 10
And outputs it as a rotation speed value SN4 by the high-speed clock SN3 transmitted from. Assuming that the pulse width of the rotation signal SN1 is Ti and the pulse width of the high-speed clock SN3 is τ, Wi = Ti / τ (i = 1, 2, 3, 3)
..) Are calculated by the speed detection unit 2. Further, the speed detector 2 outputs the rotation direction SN5 as the rotation direction of the motor 94, that is, the clockwise rotation as CW, and the counterclockwise rotation as CCW based on the phase difference between the two-phase rotation signals SN1 and SN2. The angle detection unit 3 is an up / down counter that counts up and down according to the phase difference between the two-phase rotation signals SN1 and SN2, and outputs a rotation angle value SN6.

FIG. 3 is a block diagram showing an embodiment of the speed profile generator 1, and FIG. 4 is a diagram for explaining the operation of the speed profile generator 1. Referring to FIGS. 1 and 3, in the speed profile generation unit 1, the angle setting register 12 stores a set rotation angle value SN of the motor 94.
14 are sequentially stored and output as a set angle value SN17. The angle comparison unit 13 determines that the rotation angle value SN6 is equal to the set angle value S.
When it matches with N17, it outputs an angle matching signal SN15. The speed setting register 14 sequentially stores the set rotation speed value SN16 of the motor 94 and outputs it as the set speed value SN12. The speed profile control unit 11 outputs the angle coincidence signal S
Each time N15 is received, a set rotation angle value SN1 generated from a target angle value SN13 indicating a target stop angle of the motor 94.
4 and the set rotation speed value SN16 are output.
Referring to FIG. 1, FIG. 2, FIG. 3, and FIG. 4, the target angle value SN1 of the motor 94 transmitted from the host device (not shown)
3, the speed profile control unit 11 sets Rn (n = 0, 1, 2,...) As the set rotation speed value SN16 and Pn (n = 0, 1, 2,...) As the set rotation angle value SN14.
…) Is generated. When setting the speed profile as shown in FIG. 4, first, the speed profile control unit 11 sets the motor rotation speed value change point P0 as the set rotation angle value SN14 in the angle setting register 12, and sets the motor rotation speed at this change point P0. The value R0 is set in the speed setting register 14 as the set rotation speed value SN16. When the motor 94 starts rotating and the angle of the motor 94 reaches P0, the rotation angle SN
When output from the angle detection unit 3 as 6, the angle comparison unit 13
Outputs an angle coincidence signal SN15. The speed profile control unit 11 sets the motor rotation speed value change point P1 in the angle setting register 12 as the set rotation angle value SN14 based on the angle coincidence signal SN15, and sets the motor rotation speed value R1 at this change point P1 to the set rotation speed value. It is set in the speed setting register 14 as SN16. Similarly, the speed profile control unit 11 generates the speed profile of FIG. 4 by changing the motor rotation speed values to R1 and R2 each time the angle of the motor 94 reaches P1 and P2.

FIG. 5 is a block diagram showing an embodiment of the speed controller 4. Referring to FIG. 1 and FIG. 5, the speed control unit 4 includes a set speed value SN12 and a rotation speed value SN4.
, And outputs the speed control drive voltage value SN7. The speed control unit 4 realizes a function designed based on the control theory by firmware. In the speed control unit 4, the subtractor 41 calculates a speed error e1 between the set speed value SN12 and the rotation speed value SN4. The speed integrating amplifier 42 has a function of accumulating the speed error e1 from the initial time and then multiplying the gain Ki. The state estimation mechanism 43 determines the speed control drive voltage value SN7 at time t, ie, u (t) and the rotation speed value SN.
4, that is, the state quantity of the carrier moving mechanism 9 is estimated from y (t), and S1, S2 and S3 are output. The outputs S1, S2, and S3 are linearly converted amounts of the motor rotation speed, the carrier speed, and the amount of expansion and contraction of the power transmission mechanism, respectively. The state feedback mechanism 46 is a state estimation mechanism 43
Are multiplied by the gains Kf ₁ , Kf ₂ and Kf ₃ respectively, and the output of the speed integrating amplifier 42 is added to calculate the speed control drive voltage value SN7, ie, u (t).

Next, the gains Ki, Kf ₁ , Kf ₂ and Kf of the speed integrating amplifier 42 and the state feedback mechanism 46, respectively.
_As an example of the determination method _3, a method based on the optimal regulator rule will be described. Since the carrier moving mechanism 9 in FIG. 1 is a composite system of mechanical and electric, its state equation is described in the equation of motion and the equation of voltage, and is expressed by equation (1).

[0022]

Here, u (t): a speed control drive voltage value x (t): a variable indicating a state inside the carrier moving mechanism y (t): a rotation speed value In the system represented by the formula (1), Consider a control system that causes the speed value SN4, ie, y (t), to follow the set speed value SN12, ie, r. In the process of detecting the rotational speed value y (t) at every constant time interval T of the control system, the expression (1)
Is converted to a difference equation shown in equation (2). Equation (2) is called a discrete system model.

[0024]

Here,

[0026]

The discrete system model of equation (2) is subjected to variable conversion according to equation (3) to obtain equation (4). Equation (4) is called a diffusion model.

[0028]

[0029]

The following replacement is again performed on equation (4).

[0031]

For equations (4) and (5), a suitable positive value symmetric matrix (scalar quantity x'P
(Matrix where x is x'Px> 0, P = P ')) Q and R are selected, the valence function J is defined by equation (6), and K that minimizes J is obtained.

[0033]

Ricat shown in equation (7) of the solution of equation (6)
It is known to be given by the solution of the ti equation.

[0035]

If equation (1) is a third-order differential equation, K
Is a 4 × 1 matrix shown in equation (8).

[0037]

From the equation (8), the gains Ki, Kf ₁ , Kf ₂ and Kf _{3 of the} speed integrating amplifier 42 and the state feedback mechanism 46 are obtained.

When the numerical values of Q and R given by equation (6) are changed, each element Ki, Kf ₁ , Kf ₂ of K in equation (8)
And Kf ₃ change, and the starting characteristics of the motor and the carrier speed can be adjusted.

FIG. 6 is a block diagram showing an embodiment of the state estimation mechanism 43. Referring to FIG. 6, this state estimating mechanism 43 includes three delay units 4319, 4320 and 43
Estimated amount Si at time n of the motor rotation speed, the carrier speed, and the amount of expansion and contraction of the power transmission mechanism stored in the memory 21 respectively.
(N) (i = 1, 2, 3) and the speed control drive voltage value u
(N) and the rotation speed value y (n), the time n + 1 of the motor rotation speed, the carrier speed, and the amount of expansion and contraction of the power transmission mechanism.
Is calculated (i = 1, 2, 3). The state estimating mechanism 43 includes multipliers 4301 to
4305, 4306 to 4310 and 4311 to 431
Adders 4316 and 4317 for adding the outputs of 5 respectively
And 4318, and adders 4316, 4317 and 4
318, which temporarily store the output of
4320 and 4321. Multiplier 43
01, 4306 and 4311 output the products of the output of the delay unit 4319 and the coefficients a ₁₁ , a ₂₁ and a ₃₁ , respectively. Similarly, multipliers 4302, 4307 and 4312
Is the product of the output of the delay unit 4320 and the coefficients a ₁₂ , a ₂₂ and a _32, and the multipliers 4303, 4308 and 4313 are the products of the output of the delay unit 4321 and the coefficients a ₁₃ , a ₂₃ and a ₃₃ , respectively. I do. In addition, multipliers 4304 and 4309
And 4314 a product of the speed control driving voltage u (n) and the coefficients h _1, h ₂ and h ₃ respectively outputs, multipliers 4305,4310, and 4315 rotation speed value y
The product of (n) and the coefficients g ₁ , g ₂ and g ₃ is output.

Multipliers 4301 to 43 of state estimation mechanism 43
A _ij of 05,4306～4310 and 4311-4315 each coefficient, h _i and g _i (i and j = 1,
An example of an observer algorithm called a Kalman filter will be described as an example of the determination method of 2, 3).

Equation (9) shows a model that takes into account the model internal noise w (k) and the detection noise v (k) for the discrete system model shown in equation (2).

[0043]

Here,

[0045]

Here, E [] is the time average shown in equation (11).

[0047]

Next, the quantity z, which is an estimate of the state quantity x (k),
Let (k) be Equation (12).

[0049]

Here, F = A-GC; L = B Here, the estimation condition shown in the equation (13) is given between the state quantity x (k) and the estimated quantity z (k).

[0051]

G satisfying the equations (12) and (13) is given as a solution of the Ricatti equation shown in the equation (14).

[0053]

Here,

[0055]

The multipliers 4301 to 4305 and 4306 of the state estimating mechanism 43 are obtained from the equation (15).
A of each coefficient of ４３4310 and 4311 to 4315
_ij, obtain h _i and g _i (i and j = 1, 2, 3).

FIG. 7 is a diagram showing the configuration of another embodiment of the state estimation mechanism 43. Referring to FIG. 7, this state estimator 43 has the same configuration as FIG. 6, the coefficient a _ij of each of the multiplier 4301 to 4305 in FIG. 6, h _i and g
_i (i and j = 1, 2, 3) are calculated by using an observer algorithm called a Kalman filter based on control theory to obtain multipliers 4303 and 430.
8, 4311 and 4312, coefficients a ₁₃ , a ₂₃ ,
a ₃₁ and a ₃₂ can be set to 0. That is,
The state estimation mechanism 43 in FIG.
325, 4326-4329 and 4330-4332
Adders 4333, 4334 and 4335 for adding the outputs of
Delay units 4336 and 4 for temporarily storing the outputs of
337 and 4338. Adder 432
2 and 4326 output the product of the output of the delay unit 4336 and the coefficients A ₁₁ and A ₂₁ , respectively. Similarly, multiplier 4
323 and 4327 are the output of the delay unit 4337 and the coefficient A
₁₂ and A ₂₂ , the multiplier 4330 outputs a delay 433
And it outputs the product of the output and the coefficient A ₃₃ 8. In addition, multiplier 4
324.4328 and 4331 output the product of the speed control drive voltage value u (n) and the coefficients H ₁ , H ₂ and H ₃ , respectively, and the multipliers 4325, 4329 and 4332 output the speed information y (t) and the coefficient G The product of ₁ , G ₂ and G ₃ is output. The state estimating mechanism 43 of FIG. 7 reduces the number of times of multiplication and addition as compared with the state estimating mechanism 43 of FIG.

FIG. 8 is a block diagram showing one embodiment of the angle control unit 5. As shown in FIG. Referring to FIGS. 1 and 8, in the angle control unit 5, the subtractor 51 calculates an angle error e2 between the target angle value SN13 and the rotation angle value SN6. Adder 56
Adds the value obtained by integrating the angle error e2 from the initial time point and multiplying it by a predetermined first coefficient, the value obtained by multiplying the rotation angle value SN6 by a predetermined second coefficient, and the value obtained by multiplying the rotation speed value SN4 by a predetermined third coefficient value. And outputs it as the angle control drive voltage value SN8.

FIG. 9 is a block diagram showing one embodiment of the speed angle comparing section 8. As shown in FIG. Referring to FIG. 1 and FIG. 9, in the speed / angle comparing unit 8, the speed comparator 81
Until N4 falls within the first predetermined speed range εs, when the speed control drive voltage value SN7 falls within the first predetermined speed range εs, the angle control drive voltage value SN8 is output as the control drive voltage value SN80. The speed angle comparator 82 has a rotation speed value SN4
When the rotation angle value SN6 falls within the second predetermined speed range εv and the predetermined angle range εx which are smaller than the first predetermined speed range εs, the output of the control drive voltage value SN80 as the motor drive voltage value SN9 is stopped. Otherwise, the control drive voltage value SN80 is changed to the motor drive voltage value S.
Output as N9.

FIG. 10 is a diagram showing the relationship between the rotation speed SN4 of the motor 94 and the time in the speed controller 4 and the angle controller 5, and FIG. 11 is a diagram showing the rotation speed SN4 and the rotation angle of the motor 94 in the angle controller 5. It is a figure showing relation with value SN6. The details of the angle control unit 5 and the speed / angle comparison unit 8 will be described with reference to FIGS. 1, 8, 9, 10, and 11. The speed control unit 4 controls the rotation angle value SN6 of the motor 94.
, It is difficult to accurately stop the motor 94 at the target stop angle. The angle control unit 5 and the speed angle comparison unit 8 determine that the speed of the motor 94 is at the stop threshold ε.
An angle control system for stopping the motor 94 at the target stop angle P from the point Q within s is constructed. Speed angle comparison unit 8
Is defined as a speed control drive voltage value SN7 until the rotation speed value SN4 falls within the predetermined speed range εs, and an angle control drive voltage value SN8 as the motor drive voltage value SN9 when the rotation speed value SN4 falls within the predetermined speed range εs. Output and the rotational speed value SN
4 and the rotation angle value SN6 are in the predetermined speed range εs, respectively.
When the speed falls within the narrower predetermined speed range εv and the predetermined angle range εx, the output of the motor drive voltage value SN9 is stopped. FIG.
As shown in FIG. 1, the motor 94 is controlled by the angle controller 5 described above.
Gradually becomes within the range of the threshold values εx and εv, the angle of the motor 94 converges to the target stop angle P, and the speed converges to zero.

FIG. 12 is a block diagram showing one embodiment of the pulse width modulation section 6, and FIG. 13 is a diagram showing an operation time chart of this embodiment. This embodiment will be described in detail with reference to FIGS. 1, 12, and 13. FIG. In the pulse width modulation section 6, the drive voltage value setting register 61 stores a motor drive voltage value SN9. The high-speed clock counter 63 counts the high-speed clock SN3. The drive voltage comparator 62 compares the output of the drive voltage value setting register 61 with the output of the high-speed clock counter 63, and compares the output of the drive voltage value
Is output. The high-speed clock divider 64 has a high-speed clock S
N3 is divided to output a high-speed clock divided signal SN61. The RS flip-flop 65 outputs a motor drive pulse SN62 using the high-speed clock frequency division signal SN61 as a set signal and the drive voltage coincidence signal SN63 as a reset signal. The selector 66 selectively outputs the motor drive pulse SN62 as a forward rotation motor drive pulse SN10 and a reverse rotation motor drive pulse SN11 based on the rotation direction SN5.

FIG. 14 is a block diagram showing an embodiment of the power amplifier 7. Referring to FIG. 1 and FIG. 14, in the power amplifying unit 7, four bridge-shaped transistors have one end connected to the power supply 74 and the other end connected to the motor 94. When the forward rotation motor drive pulse SN10 is input, the transistors 71 and 72 are turned on, and the motor 94
The current rotating in the direction is supplied from the power supply 74. Also,
When the reverse rotation motor drive pulse SN11 is input, the transistors 73 and 74 are turned on, and a current for rotating the motor 94 in the CCW direction is supplied from the power supply 74.

Next, an alarm generating mechanism will be described.
As shown in the above illustration, the present invention uses many delay elements or registers. Therefore, depending on the results of addition, subtraction and multiplication, overflow may occur and normal control may not be possible. Therefore, when overflow occurs and when it is determined that the drive voltage of the motor becomes an abnormal value with respect to the power supply voltage, the servo control is forcibly terminated to prevent electrical and mechanical damage. It also has a function to generate an alarm when speed and position cannot be controlled normally due to circuit damage or wiring damage in the device.

FIG. 15 is a flowchart showing the operation of the print head carrier movement control device of the present invention. The operation of the print head carrier movement control device of the present invention will be described in detail with reference to FIGS. First, in the initial setting, all registers used for control are cleared and various constants are set (S1). Next, the speed and angle of the motor 94 are detected by the speed detection unit 2 and the angle detection unit 3, and each is calculated as a numerical value (S2). Motor 94 calculated in S2
If the speed is not within the predetermined speed range εs (S3), the speed control by the speed control unit 4 is performed (S4). If the overflow does not occur during the speed control (S5), the speed / angle comparator 8 generates the motor drive voltage value SN9 and outputs the motor drive voltage value SN9.
4 is driven (S6), and since the control end flag is not set, S2 is executed again. Further, the speed of the motor 94 calculated in S2 falls within the predetermined speed range εs, and is not within the predetermined speed range εv.
If the angle of No. 4 is not within the predetermined angle range εx (S8), the angle control by the angle control unit 5 is performed (S9). If no overflow occurs during the execution of the angle control (S5), the speed / angle comparison unit 8 generates the motor drive voltage value SN9 to drive the motor 94 (S6). Execute Motor 94 calculated in S2
Is within the predetermined speed range εs, further within the predetermined speed range εv, and if the angle of the motor 94 calculated in S2 is within the predetermined angle range εx (S8), the control for ending the control is performed. A flag is set (S11), and the control ends (S7). When overflow occurs during speed control and angle control (S5), an alarm process is performed (S10), a control end flag is set (S11), and the control is ended (S5).
7).

[0065]

As described above, according to the present invention,
Speed control to detect the rotation speed value, rotation angle value and rotation direction of the motor of the carrier moving mechanism where the carrier with the print head and the motor are connected by the power transmission mechanism, and to make the rotation speed value closer to the set speed value The drive voltage value is controlled, and the angle control drive voltage value is controlled to bring the motor closer to the target angle value from the rotation speed value and the rotation angle value, and the rotation speed value and the rotation angle value are respectively set in a predetermined speed range and a predetermined angle range. Depending on the case, the speed control drive voltage value or the angle control drive voltage value is output as the motor drive voltage value or the output is stopped, and forward and reverse rotation motor drive pulses are generated from the motor drive voltage value and the rotation direction. Then, by supplying motor drive power to the motor based on the forward and reverse rotation motor drive pulses, a low-cost, malfunction-free print head A movement control apparatus is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an operation time chart of a speed detection unit and an angle detection unit in the embodiment.

FIG. 3 is a block diagram showing one embodiment of a speed profile generator in the embodiment.

FIG. 4 is a diagram illustrating an operation of a speed profile generation unit.

FIG. 5 is a block diagram showing one embodiment of a speed control unit in this embodiment.

FIG. 6 is a block diagram showing one embodiment of a state estimating mechanism in a speed control unit.

FIG. 7 is a block diagram showing another embodiment of the state estimating mechanism in the speed control unit.

FIG. 8 is a block diagram showing one embodiment of an angle control unit in this embodiment.

FIG. 9 is a block diagram showing one embodiment of a speed angle comparison unit in this embodiment.

FIG. 10 is a diagram illustrating a relationship between a rotation speed of a motor and time in a speed control unit and an angle control unit according to the embodiment.

FIG. 11 is a diagram illustrating a relationship between a rotation speed value and a rotation angle value of a motor in the angle control unit of the embodiment.

FIG. 12 is a block diagram showing one embodiment of a pulse width modulation section in this embodiment.

FIG. 13 is a diagram showing an operation time chart of the pulse width modulation unit.

FIG. 14 is a block diagram showing one embodiment of a power amplifying unit in this embodiment.

FIG. 15 is a flowchart of the operation of this embodiment.

FIG. 16 is a block diagram showing a conventional example.

FIG. 17 is a block diagram showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Speed profile generation part 2 Speed detection part 3 Angle detection part 4 Speed control part 5 Angle control part 6 Pulse width modulation part 7 Power amplification part 8 Speed angle comparison part 9 Carrier moving mechanism 10 Clock generation part 91 Print head 92 Carrier 93 Platen 94 Motor 95 Encoder 96 Power pulley 97 Driven pulley 98 Power transmission mechanism SN1, SN2 Rotation signal SN3 High-speed clock SN4 Rotation speed value SN5 Rotation direction SN6 Rotation angle value SN7 Speed control drive voltage value SN8 Angle control drive voltage value SN9 Motor drive Voltage value SN10 Forward rotation motor drive pulse SN11 Reverse rotation motor drive pulse

Continuation of the front page (56) References JP-A-4-238509 (JP, A) JP-A-1-238974 (JP, A) JP-A-63-265581 (JP, A) JP-A-3-1066893 (JP) U.S. Pat. No. 4,216,415 (US, A) WO 91/4866 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 5 / 00 B41J 19/18 H02P 5/17

Claims (7)

(57) [Claims] A motor having a printhead mounted thereon and a motor connected to each other via a power transmission mechanism, and an encoder for outputting a rotation signal of the motor; and a rotation speed value and a rotation direction of the motor based on the rotation signal. A speed detecting unit for generating, an angle detecting unit for generating a rotation angle value of the motor from the rotation signal, and a plurality of set speed values from a target angle value indicating a target stop angle of the motor and the rotation angle value.
A speed profile generation unit that sequentially outputs, a speed control unit that controls a speed control drive voltage value to bring the rotation speed value closer to the set speed value, and the motor from the rotation speed value and the rotation angle value. An angle control unit that controls an angle control drive voltage value so as to approach a target angle value, wherein the rotation speed value and the rotation angle value are within a first predetermined speed range or a second predetermined speed range and a predetermined angle range, respectively. The speed control drive voltage value or the angle control drive voltage value is output as a motor drive voltage value in some cases,
Alternatively, a speed / angle comparison unit for stopping output, a pulse width modulation unit for generating forward and reverse rotation motor drive pulses from the motor drive voltage value and the rotation direction, and a motor based on the forward and reverse rotation motor drive pulses A print head comprising: a power amplifier for supplying drive power to the motor.
In the carrier movement control device, the speed control unit includes the set speed value and the rotation speed value.
A subtractor for calculating a speed error of the signal; and a gain for the speed error.
A speed-integrating amplifier for integrating from the initial stage of multiplication, and the speed
From the control drive voltage value and the rotation speed value, the carrier speed
State estimation mechanism for estimating the amount of expansion and contraction of the power transmission mechanism
And the rotation speed value, the carrier speed, and the amount of expansion and contraction.
Multiplied by each gain and added to the output of the speed integrating amplifier
A state feedback mechanism for setting the speed control drive voltage value.
Print head carrier movement control apparatus characterized by that. 2. The method according to claim 1, wherein the speed profile generation unit sequentially stores a set rotation angle value of the motor and outputs the set rotation angle value as a set angle value, and an angle match register when the rotation angle value matches the set angle value. An angle comparing unit that outputs a signal, a speed setting register that sequentially stores a set rotation speed value of the motor and outputs the set speed value, and a target stop angle of the motor that indicates the target stop angle of the motor each time the angle coincidence signal is received. 2. The print head carrier movement control device according to claim 1, further comprising: a speed profile control unit that outputs the set rotation angle value and the set rotation speed value generated from the target angle value. 3. The state estimation mechanism according to claim 1 , wherein
Rotation speed value, the carrier speed, the expansion / contraction amount, the speed control
The product of the control voltage value and the rotation speed value with each coefficient
From the rotation speed value at the next time, the carrier
The print head carrier movement control device according to claim 1, wherein the speed and the amount of expansion and contraction are estimated . 4. An angle control unit comprising: a subtractor for calculating an angle error between the target angle value and the rotation angle value; and a value obtained by integrating the angle error from an initial time and multiplying the value by a predetermined first coefficient. An adder for adding a value obtained by multiplying a rotation angle value by a predetermined second coefficient and a value obtained by multiplying the rotation speed value by a predetermined third coefficient value, and outputting the result as the angle control drive voltage value. The print head carrier movement control device according to claim 1. 5. The speed angle comparison unit according to claim 1, wherein the speed control drive voltage value falls within the first predetermined speed range until the rotation speed value falls within a first predetermined speed range. A speed comparator that outputs a voltage value as a control drive voltage value, wherein the rotation speed value and the rotation angle value respectively fall within a second predetermined speed range and a predetermined angle range narrower than the first predetermined speed range. A speed-angle comparator that stops outputting a control drive voltage value as the motor drive voltage value, and outputs the control drive voltage value as the motor drive voltage value otherwise. Item 2. A print head carrier movement control device according to Item 1. 6. A driving voltage value setting register for storing the motor driving voltage value, a high speed clock counter for counting the high speed clock, an output of the driving voltage value setting register and the high speed clock A driving voltage comparator for comparing the output of the counter with a driving voltage matching signal to output a driving voltage coincidence signal; a high-speed clock divider for dividing the high-speed clock to output a high-speed clock dividing signal; Which outputs a motor drive pulse using the drive voltage coincidence signal as a reset signal and a set signal as a set signal.
2. The printhead carrier movement control according to claim 1, further comprising: a flip-flop; and a selector that selectively outputs the motor drive pulse as the forward rotation motor drive pulse and the reverse rotation motor drive pulse based on the rotation direction. apparatus. 7. The printhead carrier movement control device according to claim 1, wherein the power amplifying unit includes four bridge-shaped transistors having one end connected to a power supply and the other end connected to the motor.