JP3718333B2 - Pulse motor drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulse motor drive device, and in particular, but not intended to be limited to this, a pulse motor drive that drives a pulse motor at a constant speed after increasing the speed at a high acceleration and decreases the speed at a high deceleration. Relates to the device. This pulse motor driving device is used, for example, in a scanner that reads an original image and generates an image signal.
[0002]
[Prior art]
For example, in a digital copying machine, when a copy start key is pressed while a document is set on a contact glass, a carriage (movable part) integrated with a mirror and a light source of the scanner is moved to a timing belt and a pusher. -The image plane of the document on the contact glass is optically scanned by being driven in the horizontal direction by an electric motor through a power transmission mechanism such as a mirror, and the reflected light image from the image plane is each mirror and lens including the mirror. Then, an image is formed on the light receiving surface of the CCD image sensor, and an analog image signal generated by the image sensor is converted into digital data (image data). The image data is converted into image data for printing by an image processing circuit and given to a laser printer, which forms an image on transfer paper.
[0003]
Incidentally, a pulse motor is generally used as a scanning drive motor of a scanner. As is well known, in this pulse motor, a phase excitation signal (pulse) is supplied to the motor driver so that the motor driver applies a drive pulse to the pulse motor, and the pulse motor is urged to rotate. In order to rotate the motor at the self-starting frequency or higher, slow-up (rise from stop to constant speed) control or slow-down (fall from constant speed to stop) control is required.
[0004]
[Problems to be solved by the invention]
For example, in the case of scanning drive of a scanner of a copying machine, performing all of the slow-up control and slow-down control with a microprocessor that performs overall control of the entire copying machine increases the burden on the microprocessor, especially for other processing (copiers). When the control processing other than the pulse motor control is performed in parallel, the frequency of the driving pulse of the pulse motor cannot be increased so much that the copying machine as described above cannot increase the processing speed.
[0005]
Therefore, as seen in, for example, Japanese Patent Application Laid-Open No. 63-202580, the pulse motor is controlled by a microprocessor during slow-up and slow-down of the pulse motor, and the motor control provided with the microprocessor at constant speed. There has been proposed a motor controller for a printer that is controlled by a circuit.
[0006]
However, in such a conventional motor control device, the load on the microprocessor when the pulse motor is driven at a constant speed is reduced, but the micro-load when the pulse motor is slowed up or down (particularly in the vicinity of the constant speed region). The load on the processor is not reduced, and it is not possible to expect a sufficiently high speed rotation of the pulse motor, in particular, a reduction in the slow-up and down periods.
[0007]
The present invention has been made in view of the above points, and has as its first object to reduce the burden on the pulse motor drive control of the microprocessor. In addition, the pulse motor can be driven at high speed and with high accuracy. This is the second purpose.
[0008]
[Means for Solving the Problems]
(1) Composed of a combination of a bit (MSB) indicating uncoded data and data defining the cycle for representing the cycle of a series of pulses (φA, φB,...) Applied to the pulse motor. Storage means for storing an unencoded data frame and an encoded data frame formed by a combination of a bit (MSB) indicating encoded data and a plurality (5) sets of encoded data (CODE 0 to 4) ( 42) ;
Means for reading out sequential data frames from said storage means (41);
Reading out data frame, the pulse of the period the data in the data frame is defined when no data frame coding, each set of encoded within the data frame when the data frame is a coded data Pulse generating means (45) for sequentially decoding data and sequentially generating pulses having a period defined by the decoded data ; and
Pulse motor driving means said pulse generating means for driving the Lipa Rusumota (51) by the pulse generated (46);
A pulse motor driving device. In addition, in order to make an understanding easy, the code | symbol of the corresponding element of the Example shown in drawing and mentioned later is added to the parenthesis for reference.
[0009]
According to this, since the data is encoded, the amount of data is drastically reduced, the capacity of the storage means (42) can be reduced, and the cost can be reduced.
[0010]
Based on the encoded data (CODE 0 to CODE 4) of one encoded data frame, a plurality of (5) times of pulse generation processing is automatically performed by the pulse generation means (45) to read out the data frame (41 Compared with the case of reading an unencoded data frame that requires one data transfer per one pulse generation process, the load is one-fifth (5) work load and means (41) ) Is significantly reduced, and high-speed operation control of the motor, in particular, high acceleration acceleration control and high deceleration deceleration control becomes possible. When used in an image forming apparatus, productivity of image formation is improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
( 2 ) The encoded data represents a difference value with respect to the value represented by the decoded data of the data decoded in advance in time series. According to this, the decoding logic is simple, and the decoding means can be configured easily.
[0012]
(3) the pulse generating means, the read data frame, the means for generating a pulse based on the data defining the times the period of the pulse therein without data frame coding reading said data frame When the next data frame is requested to be read and the encoded data frame is read out, the first encoded data in it is decoded and a pulse is generated based on the decoded data. Similarly, when the last encoded data is decoded and a pulse is generated based on the decoded data, the means for reading the data frame is requested to read the next data frame.
[0013]
Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
[0014]
【Example】
FIG. 1 shows the configuration of a control unit of a digital copying machine equipped with an embodiment of the present invention. The embodiment of the present invention comprises a microprocessor (CPU) 41, a ROM 42 as storage means, a motor control 45 as pulse generation means, and a motor drive 46 as pulse motor drive means. A pulse motor 51 to be driven drives a carriage integrated with a mirror, a light source, and the like of a document image reading scanner of a digital copying machine via a power transmission mechanism such as a timing belt and a pulley. . In this carriage drive, the speed is increased from the home position (HP) to a constant speed in a short time with a high acceleration (slow up), and then the constant speed is maintained for a long distance (for example, the document length equivalent value). It is required to maintain, and decelerate at a high deceleration (slow down) to stop the carriage (the above is the forward stroke: original scanning), and then reverse to drive to the HP at a high speed (return stroke). The
[0015]
The ROM 42 stores data for generating a phase excitation pulse (φA, its inversion, φB, its inversion), that is, phase switching timing data, for driving the motor in the forward and backward strokes. CPU41 is provided to the motor control 45 sequentially issues reading a set of data from the ROM 42, the motor control 45, by the given data timing (time) at each phase excitation signal (.phi.A, its inversion, [phi] B , Its inversion) is switched from 1 (high level H) to 0 (low level L) or vice versa. Thereby, each phase excitation signal becomes a pulse, that is, a phase excitation pulse. These pulses are applied to the motor drive 46, and the motor drive 46 turns on (energized) / off (non-energized) each phase of the pulse motor 51 in response to the phase excitation pulse, that is, pulse-drives. 51 rotates. The rotation speed corresponds to the phase switching speed (phase excitation pulse cycle), and the rotation direction is determined by the energization order (excitation phase order) for each phase.
[0016]
For one round trip of the carriage, the forward acceleration section from the start of the forward movement, the forward constant speed section (document scanning section), the forward deceleration section, the reverse acceleration section from the start of the backward movement to the constant speed, It is divided into a speed zone and a deceleration zone that decelerates and stops at HP. In the forward constant speed section (document scanning section) and the reverse constant speed section, it is only necessary to perform phase switching at a constant cycle, so that it is not necessary to sequentially read out a series of data from the ROM. Therefore, the ROM 42 may be provided only with phase switching timing data necessary in the forward acceleration section, the forward deceleration section, the reverse acceleration section, and the reverse deceleration section.
[0017]
As the phase switching timing data, that is, phase excitation cycle data, 16-bit data is generally used in the case of scanner driving. Therefore, in this embodiment, it is 16 bits. Hereinafter, this 16-bit group is referred to as a data frame.
[0018]
FIG. 2 shows the data structure of the data frame. One frame has a 16-bit configuration. The most significant bit (hereinafter referred to as MSB) indicates whether the data of this frame is encoded data or actual data. When the MSB is 1, it means that the subsequent 15 bits are encoded data. In this embodiment, the encoded data represents a difference value with respect to a value represented by decoded data (corresponding to actual data) of data decoded in time series. One piece (one set) of encoded data is 3 bits, and a total of five pieces of encoded data CODE0 to CODE4 are included in one data frame.
[0019]
When the MSB is 0, the subsequent 15 bits are one piece of actual data (uncoded data).
[0020]
The first data frame of a series of data frames (data frame group) addressed to the forward acceleration section in the ROM 42 requires actual data as a base point at the time of forward acceleration (start of driving) of the carriage. A frame followed by a data frame is an encoded data frame having an MSB of 1. However, the place where the difference value cannot be expressed by 3 bits is an actual data frame in which the MSB is 0. The data frame group addressed to the backward acceleration section is the same as that directed to the forward acceleration section. However, since the motor driving speed is different in the forward stroke and the backward stroke, the acceleration / deceleration characteristics are also different. Therefore, the number of data frames in the data frame group is different, and the value represented by the data in the data frame is also different.
[0021]
Since the data frame group addressed to the forward / decelerated section is a deceleration from a constant speed, the MSB is an encoded data frame of 1. However, the place where the difference value cannot be expressed by 3 bits is an actual data frame in which the MSB is 0. The data frame group destined for the return deceleration section is the same as that for the forward deceleration section.
[0022]
The CPU 41 designates the above-described data frame group corresponding to which section the carriage is in, sequentially reads out the data frames in the group from the ROM 42, and gives them to the motor control 45.
[0023]
Each group includes data for designating acceleration / deceleration and data for designating the motor rotation direction (phase switching order). The CPU 41 decodes these data and gives a control signal to the motor control 45. Thus, the phase sequence (motor rotation direction) of the pulses generated by the motor control 45 is set, but the description of this phase sequence setting is omitted.
[0024]
FIG. 3 shows a functional configuration of the motor control 45. In addition, illustration of the function part relevant to a phase order (motor rotation direction) setting was abbreviate | omitted. Next, the internal functions of the motor control 45 will be described with reference to a flowchart (FIG. 5).
[0025]
FIG. 4 shows an outline of the pulse motor drive control of the CPU 41, and FIG. 5 shows an outline of the pulse generation control of the control unit CPU 451 of the motor control 45. Refer to FIG. 3, FIG. 4, and FIG. 5 below.
[0026]
When the CPU 41 activates a start signal to the motor control 45, the control unit CPU 451 of the motor control 45 activates a data request signal to the CPU 41 (step 1 in FIG. 4 and steps 11 and 12 in FIG. 5). . In the following, the word “step” is abbreviated in parentheses, and step no. Write numbers only.
[0027]
When the data request signal becomes active, the CPU 41 reads the first data frame from the data frame group previously selected by the CPU 41 in the ROM 42 and writes it into the data register 452 of the motor control 45 (2, 3 in FIG. 4).
[0028]
When the data is written, the control unit CPU 451 checks the MSB of the data register 452, and if it is 0, it is regarded as actual data (the first data frame is actual data at the start), and the actual data (all of CODE0 to CODE4). bit), and transferred to the base register 455 via the selector 454, the data written to the base register 455 via the selector 457 transfers to the pulse generator 458 (13-17 in Figure 5).
[0029]
The pulse generator 458 sets the phase excitation signal φA etc., which is output to the motor drive 46, to the start point (start) level, and switches the level of the phase excitation signal φA etc. when the time indicated by the given data has elapsed. Then, a data request signal is given to the control unit CPU 451. In response to this, the control unit CPU 451 proceeds to step 12 in FIG. 5 to request the CPU 41 for the next data frame, and the CPU 41 reads the next data frame from the ROM 42 and writes it in the register 452 (2, 3 in FIG. 4). ).
[0030]
As a result, when the MSB becomes 1, when the acceleration signal from the CPU 41 is active (acceleration is designated), the control CPU 451 first designates the first encoded data CODE0 (15 in FIG. 5). , 19, 20), which is added to the subtractor 456 via the selector 453,
1a) In adder / subtracter 456, the value represented by CODE0 (3 bits) is subtracted from the value of the base register 455 (previous output value) (21 in FIG. 5);
2a) The subtraction result value (current value) is transferred to the pulse generator 458 via the selector 457. At the same time, the data is transferred to the base register 455 via the selector 454. That is, the data in the base register 455 is updated to the current value (decoded data). When the time indicated by the current value elapses, the pulse generator 458 switches the level of the phase excitation signal φA and the like and supplies a data request signal to the control unit CPU 451 (22 in FIG. 5);
3a) In response to this data request signal, the control unit CPU 451 designates the next encoded data (23 in FIG. 5), and if there is the next encoded data, the above 1a) is performed in the same manner, except that CODE0 is Then, it replaces and executes the encoded data that has just been specified, and executes the above 2a) in the same manner, and arrives at the book 3a). Here, when there is no next encoded data (the above processing has been executed until CODE 4), the control unit CPU 451 requests the next data frame from the CPU 41 (23, 24, 25, 12 in FIG. 5);
While the start signal is active, the above process is repeated.
[0031]
On the other hand, when the acceleration signal from the CPU 41 is inactive, the control unit CPU 451 first designates the first encoded data CODE0 (26 in FIG. 5),
1b) Add the value represented by CODE0 (3 bits) to the value of the base register 455 (previous output value) (27 in FIG. 5);
2b) The value of the result of addition (current value) is transferred to the pulse generator 458. At the same time, the data is transferred to the base register 455. That is, the data in the base register 455 is updated to the current value. When the time indicated by the current value elapses, the pulse generator 458 switches the level of the phase excitation signal φA and the like and supplies a data request signal to the control unit CPU 451 (28 in FIG. 5);
3b) In response to this data request signal, the control unit CPU 451 designates the next encoded data, and if there is the next encoded data, the above 1b) is the same, except that CODE0 is designated this time. This is replaced with the encoded data and executed, and the above 2b) is executed in the same manner to arrive at the book 3b). Here, when there is no next encoded data (the above processing has been executed until CODE 4), the control unit CPU 451 requests the CPU 41 for the next data frame (29, 30, 31, 12 in FIG. 5);
While the start signal is active, the above process is repeated.
[0032]
As described above, when the data frame is an encoded data frame, the CPU 41 only needs to read the data frame from the ROM 42 and give it to the motor control 45 once every five excitation phase changes. This is reduced to 1/5 of the actual data frame. Of course, the amount of data in the ROM 42 can be reduced, and the pulse motor 51 can be accelerated and decelerated at a higher speed (shorter time) as much as the CPU 41 can afford.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an outline of a control system for a copying machine equipped with an embodiment of the present invention.
2 is a plan view showing a data configuration of a data frame for pulse motor drive control stored in a ROM 42 shown in FIG. 1; FIG.
3 is a block diagram showing a functional configuration of a motor control 45 shown in FIG. 1. FIG.
4 is a flowchart showing an outline of a control operation for a motor control 45 by a CPU 41 shown in FIG.
FIG. 5 is a flowchart showing an overview of a phase excitation pulse generation process of a control unit CPU 451 shown in FIG. 3;
[Explanation of symbols]
452: Data register 453: Data selector 454: Data selector 455: Base register 456: Adder / subtractor 457: Data selector

Claims (3)

A non-encoded data frame composed of a combination of a bit indicating non-encoded data and data defining the cycle for representing a cycle of a series of pulses applied to the pulse motor, and encoded data. Storage means for storing a bit to be indicated and an encoded data frame comprising a combination of a plurality of sets of encoded data ;
Means for reading out sequential data frames from said storage means;
Reading out data frame, the pulse of the period the data in the data frame is defined when no data frame coding, each set of encoded within the data frame when the data frame is a coded data Pulse generating means for sequentially decoding data and sequentially generating pulses having a period defined by the decoded data ; and
Pulse motor driving means for said pulse generating means to drive by lipase Rusumota the pulses generated;
A pulse motor driving device. The pulse motor driving device according to claim 1, wherein the encoded data represents a difference value with respect to a value expressed by decoded data of data decoded in time series in advance. It said pulse generating means, the read data frame, the next data sometimes the means for reading the data frame and generating a pulse based on the data defining the pulse period of the therein encoded no data frames When a frame is requested to be read and the encoded data frame is read , the first encoded data in it is decoded and a pulse is generated based on the decoded data, and this is repeated in the same manner until the last encoded data. 3. The pulse motor driving device according to claim 1 , wherein when the last encoded data is decoded and a pulse is generated based on the decoded data, the means for reading the data frame is requested to read the next data frame ; .

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