JP4654512B2 - Stepping motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a stepping motor that controls the amount and speed of movement of a stepping motor used for moving an ink head of a printing apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a stepping motor used for moving an ink head of a printing apparatus is composed of a stator and a rotor having a plurality of phases of excitation coils. There are various methods such as phase excitation, two-phase excitation, two-three-phase excitation, three-phase excitation, and four-phase excitation.
[0003]
In general, an excitation current is supplied to each excitation coil by a predetermined constant phase excitation method. The supply of the excitation current to such an excitation coil is, for example, a control device configured as shown in FIG. Is done. That is, for example, the CPU 1 including a microcomputer controls each unit in accordance with a predetermined control program stored in the ROM 2. In the case of a printer, printing is performed based on print data from the printer driver side of a host computer (not shown). In order to perform predetermined control such as control, various signals are output from the CPU 1.
[0004]
Although not shown in FIG. 4, the excitation current is supplied according to a predetermined phase excitation method for controlling the carrier motor for moving the ink head composed of a stepping motor and the feed motor for paper feeding. As described above, a control signal including a pulse signal is output from the CPU 1 via the ASIC 3 to the carrier motor driver 4 for driving the carrier motor corresponding to the driving unit and the feed motor driver 5 for driving the feed motor. An excitation current is supplied to each excitation coil (not shown), and each motor is driven by a required number of steps corresponding to the print data described above.
[0005]
By the way, in the case of a stepping motor, for example, when stopping, even if the rotor rotates the required number of steps due to the friction and inertia of the mechanism part, it does not stop at the specified position and is constant at the start. There are specific problems that the rise time until reaching the speed varies or the rotational speed is unstable and vibrates.
[0006]
For this reason, a ramp table comprising correction data for acceleration and correction data for deceleration is usually stored to maintain the desired acceleration and deceleration characteristics at the start and stop of the rotor. A storage unit 6 comprising a RAM or the like is provided, and the CPU 1 reads acceleration correction data and deceleration correction data from the ramp table of the storage unit 6, and stores them in the register 31 built in the ASIC 3. An excitation current based on these data is supplied to each excitation coil.
[0007]
Here, as the correction data at the time of acceleration stored in the storage unit 6, normally, every fixed time during the acceleration to be output from the CPU 1 so that the time from the start of startup to the stabilization of the speed is within a predetermined time. The pulse frequency data of the control signal is stored, and the pulse frequency increases as time elapses. On the other hand, as the correction data at the time of deceleration stored in the storage unit 6, the pulse frequency data of the control signal for every fixed time during the deceleration to be output from the CPU 1 is constant so that the time from the start of deceleration to the stop is constant. The stored data is such that the pulse frequency decreases as time passes.
[0008]
Since the speed is kept constant during acceleration and deceleration, it is not particularly necessary to store the data in the storage unit 6 as correction data. Therefore, when the number of motor steps and the motor speed from the acceleration start position to the deceleration end position are the horizontal axis and the vertical axis, respectively, the ramp table including the constant speed region is shown as a relationship between the motor step number and the motor speed. It becomes a trapezoid shape.
[0009]
However, according to such a trapezoidal lamp table, especially in the case of a carrier motor for moving the print head, in order to perform stable printing, printing cannot be started until a constant speed (maximum speed) is reached. There is an inconvenience that the start of printing is delayed and the time required for printing becomes long. Therefore, in order to eliminate such inconvenience, it has been proposed to use a so-called parabolic lamp table having a semicircular or semielliptical shape instead of the trapezoidal shape described above.
[0010]
Specifically, this type of parabolic lamp table is a motor startup waveform indicating the relationship between the rotation speed of a stepping motor and the number of pulses applied to the stepping motor, as described in JP-A-10-150800. (In other words, the waveform of the ramp table here) is a quadratic function, and is a semicircle or semi-elliptical shape as described above.
[0011]
In the case of a printer, the shape (or waveform) of the parabolic lamp table is different for each line depending on, for example, the length of print data for each line, or the print mode such as the fine mode or the normal mode.
[0012]
[Problems to be solved by the invention]
However, when a plurality of patterns of parabolic lamp tables are stored in this way, the amount of data in each of the parabolic lamp tables is very large, and a large number of parabolic lamp tables having a large amount of data are stored as the storage unit 6. There is a problem that it requires a storage capacity and causes an increase in cost.
[0013]
Therefore, only one type of parabolic lamp table serving as a reference is stored in the storage unit 6, and the data of the reference parabolic lamp table is appropriately expanded and contracted by calculation to derive a parabolic lamp table corresponding to the length of print data. However, since the data amount of the reference parabolic lamp table itself is very large, it takes a very long time to calculate the expansion / contraction of the reference parabolic lamp table, and there is a problem that the burden on the CPU 1 that performs the calculation increases.
[0014]
Incidentally, as methods for reducing the capacity of the lamp table of the stepping motor, there are those described in Japanese Patent Laid-Open No. 3-139198 and registered utility model publication No. 3060473, but these reduce the data amount of the lamp table. This is to reduce the memory capacity of the ROM or the like for storing this, but it is not related to the parabolic lamp table as in the present invention, and it is half by reversing the reading direction at the time of acceleration and deceleration of the motor. It is not intended to be able to cope with the amount of data.
[0015]
Therefore, an object of the present invention is to reduce the capacity of the storage unit and to simplify necessary calculations.
[0016]
In order to achieve the above-described object, the present invention includes a multi-phase excitation coil for a stator, a drive unit that supplies an excitation current to each of the excitation coils to rotate the rotor, and a required number of steps. A stepping motor moving amount and speed used for moving an ink head of a printing apparatus, and a control unit that outputs a control signal to the driving unit and a storage unit that stores a ramp table composed of the step number data. In the control device for the stepping motor that controls the motor step number, when the motor step number and the motor speed are the horizontal axis and the vertical axis, respectively, the motor speed is a reference quadratic curve representing the relationship between the motor step number and the motor speed. comprising a storage unit that stores a reference ramp table of half of the data from zero to the maximum value, the control unit, the reference La during acceleration Sequentially reading the data of the motor speed of up table to a maximum value from zero from the storage unit, and similar deformable at a magnification corresponding to the length or the printing mode of the print data from the host computer, based on the data after deformation and it generates the control signal Te is characterized by generating a pre-SL control signal toward zero from the maximum value of the motor speed based on the data after the deformation at the time of deceleration.
[0017]
According to such a configuration, at the time of acceleration, the motor speed is read out reference ramp table of data sequentially to the highest value direction from zero, similar to a magnification corresponding to the length or the printing mode of the print data from the host computer A control signal is generated based on the deformed data after deformation, and a control signal is generated based on the data after deformation from the maximum value of the motor speed to the zero direction during deceleration.
[0018]
Therefore, the data to be stored in the storage unit may be half the data of the reference quadratic curve, and the storage unit capacity can be reduced. In addition, if the data of the reference ramp table is modified similarly during acceleration, there is no need to re-transform the data during deceleration, so the data of the entire reference quadratic curve that forms the basis of the reference ramp table is modified similarly. Compared with the case of processing, the number of calculations required is half, and the calculation process can be simplified.
[0019]
In addition, the present invention controls a plurality of excitation coils for a stator, a drive unit that supplies an excitation current to each excitation coil to rotate the rotor, and the drive unit that drives the required number of steps. A stepping motor control for controlling a moving amount and a speed of a stepping motor used for moving an ink head of a printing apparatus, comprising a control unit that outputs a signal and a storage unit that stores a ramp table including the data of the number of steps. In the apparatus, when the motor step number and the motor speed are the horizontal axis and the vertical axis, respectively, among the standard quadratic curves representing the relationship between the motor step number and the motor speed, the motor speed is half from zero to the maximum value. A storage unit storing a plurality of patterns of deformed lamp tables obtained by similar deformation of a reference lamp table comprising the data of However, from the storage unit, the necessary one of the ramp tables is read from zero to the maximum value direction during acceleration, and from the maximum motor speed value to zero direction during deceleration, the control signal is generated. It is also possible to configure so as to.
[0020]
According to such a configuration, since the data amount of the reference ramp table is half the data amount of the entire reference quadratic curve, the data of each pattern obtained by deforming the entire reference quadratic curve in a similar manner. Compared to storing the lamp, the storage capacity is only half, and it is only necessary to read out the necessary one of the lamp tables. Can be
[0025]
In the invention, it is preferable that the controller controls ejection of the ink head by deriving ejection timing of the ink head based on the data after deformation. According to such a configuration, it is possible to accurately derive the ejection timing of the ink head according to the length of the print data and the print mode, and to accurately control the ejection of the ink head.
[0026]
Further, according to the present invention, the storage unit stores a plurality of modified lamp tables obtained by deforming the reference lamp table in a similar manner, and the control unit stores a necessary one of the lamp tables from the storage unit. It is also possible to read the motor speed from zero toward the maximum value during acceleration and to read the motor speed from the maximum motor speed toward zero during deceleration to generate the control signal .
[0027]
According to such a configuration, since the data amount of the reference ramp table is half the data amount of the entire reference quadratic curve, the data of each pattern obtained by deforming the entire reference quadratic curve in a similar manner. Compared to storing the lamp, the capacity of the storage section is only half, and it is only necessary to read out the required lamp table of the storage section. Processing can be simplified.
[0028]
Further, the present invention may be configured such that the control unit derives the ejection timing of the ink head based on the data of the ramp table read from the storage unit and controls the ejection of the ink head. .
[0029]
According to such a configuration, it is possible to accurately derive the ejection timing of the ink head according to the length of the print data and the print mode, and to accurately control the ejection of the ink head.
[0030]
Specifically described with reference to FIGS. 1 to 3 with the application the case of the present invention to an inkjet printer is a printing device. However, FIGS. 1 and 2 are operation explanatory diagrams, and FIG. 3 is a flowchart for explaining the operations. The basic configuration of the control device of the printer is the same as the conventional case described above, in the following with reference also to FIG. 4, the description will center on the differences from the primarily conventional.
[0031]
In this specific example , the storage unit 6 has a semi-circular or semi-elliptical reference secondary representing the relationship between the motor step number and the motor speed when the motor step number and the motor speed are the horizontal axis and the vertical axis, respectively. Among the curves, for example, as shown by a solid line in FIG. 1, a reference ramp table Rs consisting of half of the motor speed from zero to the maximum value is stored, and the reference ramp table Rs is similarly modified. In addition to the deformed lamp table Rd having a pattern as indicated by a one-dot chain line in FIG. .
[0032]
As shown in FIG. 2, the CPU 1 reads the necessary one of the modified ramp tables from the storage unit 6 in the direction of the maximum value Vm from “0” during acceleration, and the maximum value of the motor speed during deceleration. A control signal to be read from Vm in the “0” direction and to be given to each motor driver 4, 5 as a drive unit via the ASIC 3 is generated.
[0033]
Further, the CPU 1 derives the ejection timing of the ink head based on the data of the lamp table read from the storage unit 6 and controls the ejection of the ink head. Such control signal generation processing by the CPU 1 and ink head ejection control processing correspond to the control unit.
[0034]
Next, the lamp table processing operation in the CPU 1 will be described with reference to the flowchart of FIG.
[0035]
As shown in FIG. 3, a lamp table corresponding to the length of print data from the host computer and the print mode is selected from the reference lamp table Rs and each modified lamp table Rd stored in the storage unit 6. Data is read from the read address of the lamp table from the storage unit 6 (S1), and the read data of the lamp table is written and stored in the register 31 of the ASIC 3 (S2).
[0036]
Then, it is determined whether or not the read address at that time is an address storing data corresponding to the motor speed maximum value Vm (see FIG. 2) (S3). Is the stored data of the address corresponding to the motor speed “0”, and the read address is added to form data at the time of acceleration (S4), and then the process returns to the above-described step S1 to repeat the processes after step S1. As a result, control data for the excitation current during acceleration is formed.
[0037]
On the other hand, if the determination result in step S3 is YES, the read address is subtracted to form data during deceleration (S5), and the read address data after subtraction is read (S6) and read. The stored data is written and stored in the register 31 of the ASIC 3 (S7), and it is determined whether or not the read address at that time is an address storing data corresponding to the motor speed “0” (S8).
[0038]
If this determination result is NO, the process returns to step S5 described above and the processing from step S5 is repeated to form excitation current control data during deceleration, and if the determination result is YES, the operation ends. .
[0039]
In this way, the CPU 1 sequentially reads out the reference ramp table data from the storage unit 6 in the direction of the motor speed from zero to the maximum value during acceleration, and the reference ramp table data from the maximum value of the motor speed in the zero direction during deceleration. Are sequentially read from the storage unit 6, and control data of the excitation current is generated based on the read data.
[0040]
Therefore, according to the specific example described above, since the data amount of the reference ramp table Rs is half the data amount of the entire reference quadratic curve that is the basis thereof, each of the reference quadratic curve as a whole is similarly transformed. Compared with the case of storing pattern data, the capacity of the storage unit 6 can be halved, and it is only necessary to read out the necessary one of the lamp tables. The arithmetic processing in the CPU 1 can be simplified.
[0041]
In addition, the ejection timing of the ink head according to the length of the print data from the host computer and the printing mode can be accurately derived, and the ejection control of the ink head can be performed with high accuracy.
[0042]
Here, as the implementation form of the invention, the storage unit 6, for example only the reference lamps Table RS in FIG. 1 may be stored for a maximum value from the motor speed "0" of the reference ramp table Rs from the storage unit 6 Data is sequentially read out in the direction, and the data is deformed in a similar manner at a magnification according to the length of the print data from the host computer and the print mode, and the excitation current control data is generated based on the deformed data. The excitation current control data is generated based on the data deformed in the “0” direction from the highest value of the current .
[0043]
In this case, the data to be stored in the storage unit 6 may be half the data of the reference quadratic curve, and the capacity of the storage unit 6 can be reduced, as well as the data of the reference ramp table during acceleration. Therefore, when the vehicle is decelerated, it is not necessary to perform the deformation process again. Therefore, the calculation required is half that of the case where the data of the entire reference quadratic curve, which is the basis of the reference ramp table, is similarly processed. Thus, the arithmetic processing can be simplified.
[0044]
Furthermore, in the above-described embodiment, the case where the present invention is applied to a printer has been described. However, the present invention is not particularly limited to a printing apparatus such as a printer, and can be applied to all stepping motors. The same effect can be obtained.
[0045]
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.
[0046]
As described above, according to the present invention, the data to be stored in the storage unit may be half the data of the reference quadratic curve, and the capacity of the storage unit can be reduced. Furthermore, if the data of the reference ramp table is similarly modified during acceleration, there is no need to re-transform the data during deceleration. Therefore, the data of the entire reference quadratic curve that forms the basis of the reference ramp table is similarly modified. Compared with the case of processing, the number of calculations required is half, and the calculation process can be simplified.
[0050]
In addition, according to the present invention, it is possible to accurately derive the ejection timing of the ink head according to the length of the print data and the print mode, and to accurately control the ejection of the ink head.
[Brief description of the drawings]
FIG. 1 is an operation explanatory diagram of one embodiment of the present invention.
FIG. 2 is an operation explanatory diagram of one embodiment of the present invention.
FIG. 3 is a flowchart for explaining the operation of the embodiment of the present invention.
FIG. 4 is a block diagram of a control device in a general printer.
FIG. 5 is an operation explanatory diagram of the configuration of FIG. 4;
[Explanation of symbols]
1 CPU (control unit)
4 Carrier motor driver (drive unit)
5 Feed motor driver (drive unit)
6 storage

Claims (2)

A multi-phase excitation coil for a stator, a drive unit for supplying an excitation current to each excitation coil to rotate the rotor, and a control unit for outputting a control signal to the drive unit to drive the required number of steps And a stepping motor control device for controlling the moving amount and speed of the stepping motor used for moving the ink head of the printing apparatus, comprising a storage unit storing a ramp table composed of the step number data.
From the standard quadratic curve representing the relationship between the number of motor steps and the motor speed, where the motor speed is zero and the maximum value, when the motor step number and the motor speed are the horizontal axis and the vertical axis, respectively. A storage unit storing a reference lamp table,
Wherein, the acceleration at the time of successively reading data up to the maximum value from the motor speed is zero the reference ramp table from the storage unit, similar to a magnification corresponding to the length or the printing mode of the print data from the host computer deformed, generates the control signal based on the data after deformation, at the time of deceleration and generating a pre-SL control signal toward zero from the maximum value of the motor speed based on the data after the deformation Stepping motor control device. Wherein the control unit, the control device of the stepping motor according to claim 1, characterized in that the injection control of the ink head to derive the injection timing of the ink head based on the data after the deformation.

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