JP2004129443A - Drive control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive control device that accommodates all speeds without increasing the load of a CPU and the capacity of a storage device. <P>SOLUTION: A start address of an acceleration pattern (a) is written to an address register Ar0 of the acceleration pattern (a), and a termination address 500 is written to an address register Ar1. An address 1320 of as acceleration pattern (b) that has a high speed nearest to the speed of the drive clock number of the address 500 is written to an address register Ar2 of the acceleration pattern (a), and a termination address 1480 is written to an address register Ar3. Then, a part of the acceleration pattern (a) is substituted with a part of the acceleration pattern (b), and the acceleration pattern (a) indicated by a dotted line is obtained. By shifting the speed to a constant-speed state further quickly than the previous acceleration pattern (a) and elongating the feeding time until an image read time, a speed variation can be suppressed before the time of starting the reading. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a drive control device that is mounted on an image reading device such as a scanner device and drives a traveling body that optically scans a document using a stepping motor, and particularly when the stepping motor is accelerated. The present invention relates to a drive control device using a pattern indicating a change in a pulse frequency input to a stepping motor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image reading apparatus such as a scanner apparatus, a facsimile apparatus, and a copying apparatus, a stepping motor is used as a driving device of a traveling body that optically scans a document.
This stepping motor can control the rotation angle by the number of input pulses to the drive circuit, and can control the rotation speed by the frequency of this input pulse.
Therefore, the drive control device of the stepping motor stores a drive table indicating a drive pattern, which is change information of the frequency of the input pulse, in the storage device, and stores the drive table in the storage device according to a drive state such as acceleration or deceleration. The drive table is read and drive control of the stepping motor is performed.
In recent years, among these drive tables, various techniques for improving an acceleration table indicating an acceleration pattern used for controlling acceleration drive of a stepping motor have been disclosed, including the following patent documents.
[Patent Document 1]
JP 2000-196823 A [Patent Document 2]
JP-A-10-257244 [0003]
Patent Literature 1 discloses an acceleration table storage device that stores an acceleration pattern, which is a change in an input pulse frequency of a stepping motor corresponding to a plurality of reading magnifications, and stores the acceleration table in the acceleration table based on a designated reading magnification. There is disclosed a technique for reducing the load on a CPU (Central Processing Unit) in a control device by selecting.
Patent Document 2 discloses a technique in which an acceleration table used for controlling acceleration driving of a stepping motor is created by a CPU in a control device every time the reading magnification of a document is changed.
[0004]
[Problems to be solved by the invention]
However, in the image reading apparatus described in Patent Literature 1, although the load on the CPU is reduced, it is necessary to increase the storage capacity in order to secure an area for storing the corresponding drive table.
Further, in the image reading apparatus described in Patent Literature 2, the storage capacity required for the acceleration table is reduced, but the load on the CPU increases because the CPU creates the acceleration table according to the control speed.
Therefore, according to the present invention, when there are a plurality of types of control speeds, an acceleration table indicating a minimum acceleration pattern is stored, and an acceleration pattern corresponding to the load-side speed is created by combining some of these acceleration patterns. Accordingly, it is an object of the present invention to provide a drive control device capable of coping with any speed without increasing the load on the CPU and the capacity of the storage device.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a driving device for driving a load, a storage device for storing an acceleration table for instructing acceleration driving of the load in the driving device, and a constant speed table for instructing constant speed driving, Creating means for creating a drive table for instructing acceleration drive, deceleration drive, or constant speed drive by combining the acceleration table and the constant speed table stored in the storage device; The means achieves the object by controlling the driving of the load based on the drive table created by the creating means.
According to a second aspect of the present invention, in the first aspect of the present invention, the creation means changes the combination of the acceleration table and the constant speed table in accordance with the driving speed of the load to achieve the object. To achieve.
[0006]
According to a third aspect of the present invention, in the first or second aspect of the invention, the storage device stores a self-starting frequency for accelerating at a stretch at an automatic frequency, and the driving unit controls the stepping motor. When used, the stepping motor achieves the object by driving based on the self-starting frequency.
According to a fourth aspect of the present invention, in the first, second, or third aspect, the load is a scanning optical system of the image reading device that scans and reads a document of the image reading device. Achieves the above object.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of an image reading apparatus equipped with a drive control device of the present invention will be described in detail with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of a drive system of the image reading apparatus according to the present embodiment.
As shown in FIG. 1, the drive system of the image reading apparatus includes a first carriage 1, a second carriage 2, a wire 3, a drive shaft 4, a wire pulley 5, idle pulleys 6a to 6d, a timing belt 7, a stepping motor 8, Timing belt pulleys 9 and 10, a detection unit 11 and a home position sensor 12 are provided.
The first carriage 1 and the second carriage 2 are moving bodies that scan and read an original, and are referred to as a scanning optical system.
[0008]
FIG. 2 is a diagram illustrating a configuration of the image reading apparatus according to the present embodiment.
Contact glass (original table) 13, exposure lamp 14, first mirror 15, second mirror 16, third mirror 17, imaging lens 18, CCD (charge coupled device) 19, scanner control board 20, and microstep drive control board 21.
The scanner control board 20 controls the image processing and the micro-step drive control board 21 of the stepping motor 8. The micro step drive control plate 21 includes a motor drive power supply (DC (direct current) 24 V) for the stepping motor 8 and a drive circuit for controlling the driving of the stepping motor 8.
[0009]
Next, an operation of the image reading apparatus thus configured will be described.
The first carriage 1 integrally has an exposure lamp 14 and a first mirror 15, and scans an original. The second carriage 2 integrates the second mirror 16 and the third mirror 17 and guides light from the first carriage 1 to the imaging lens 18.
Power is transmitted to the first carriage 1 and the second carriage 2 via wires 3 stretched over two objects. The wire 3 is driven by a wire pulley 5 wound and integrated with a drive shaft 4. The wire pulley 5 is driven by a timing belt pulley 10 integrated with a shaft of a stepping motor 8 via a timing belt pulley 9 and a timing belt 7 which are coaxial.
[0010]
When the power switch is turned on, the stepping motor 8 starts driving for homing, and the first carriage 1 and the second carriage 2 move in the forward direction in FIG. When the first carriage 1 and the second carriage 2 have moved a certain distance, they start moving in the return direction in FIG. Then, when the home position sensor 12 detects the detection unit 11 below the first carriage 1, the first carriage 1 and the second carriage 2 move by a predetermined pulse and stop. At this position (hereinafter, the home position is HP), the first carriage 1 and the second carriage 2 are on standby, and start a reading operation when a reading command is issued.
[0011]
FIG. 3 is a diagram showing a schematic configuration of a drive control system of the image reading apparatus according to the present embodiment.
When a document is placed on the contact glass 13 and a start key (not shown) is pressed, a stepping motor drive clock is output from the scanner control board 20 to the micro step drive control board 21 at a predetermined timing. At the same time when the stepping motor 8 starts driving, the first carriage 1 and the second carriage 2 start moving from the HP in the forward direction of FIG.
The stepping motor 8 is driven by a micro-step drive control board 21. The micro-step drive control board 21 receives a stepping motor drive clock, a forward / reverse rotation signal, a clock signal from a scanner control board 20 equipped with an upper CPU (central processing unit). A division number switching signal and a driving current switching signal for microstep driving are input.
The micro step drive control plate 21 controls the drive current flowing through each phase of the stepping motor 8 based on these signals.
[0012]
The speed of the stepping motor 8 is determined by the drive clock frequency. The micro-step drive control plate 21 controls the switching timing of each phase of the stepping motor 8 according to the drive clock frequency. Thus, the speed of the stepping motor 8 is high when the frequency is high, and is low when the frequency is low, so that various kinds of slow-up control can be performed by controlling the drive clock frequency.
The microstep drive control plate 21 switches the drive current depending on the state of slow-up, slow-down, reading operation, return, standby, or the like, or switches the number of one-step divisions of the stepping motor 8 to change the stepping motor. 8 is controlled.
Thus, the drive control is performed based on the speed pattern of the stepping motor 8.
[0013]
FIG. 4 is a diagram showing a basic driving pattern of the carriage.
FIG. 5 is a diagram showing a change in a motor drive pulse during image reading magnification change.
The scanner control board 20 controls the stepping motor drive clock to be given to the micro-step drive control board 21 by dividing the pattern into acceleration, constant speed, and deceleration patterns in the forward direction and acceleration, constant speed, and deceleration patterns in the return direction.
In the constant speed portion, the speed of document reading can be varied in 1% increments up to 400% in the enlargement direction and up to 25% in the reduction direction, centering on the speed of the same size (100%).
In the acceleration pattern, acceleration control is performed such that fluctuations in the speed of the carriage are suppressed before the document reading starts for these speeds.
[0014]
Conventionally, in order to suppress the vibration generated during the acceleration control, several acceleration tables are stored in accordance with a constant speed, and the acceleration table is divided into a plurality of blocks for a speed of 25% to 400%. Was.
FIG. 7 is a diagram showing a carriage driving pattern during conventional acceleration.
In the conventional example shown in FIG. 7, (a) pattern: acceleration pattern from 25% to 50%, (b) pattern: acceleration pattern from 51% to 71%, (c) pattern: acceleration from 72% to 100% Pattern, (d) Pattern: Since four acceleration tables of 101% to 400% are used, a storage area for four tables is required.
[0015]
However, in the conventional driving pattern, as shown in FIG. 7, since the acceleration is rapid from the reduction direction of about 25% to about 50%, the speed fluctuation at the time of acceleration before the image reading starts due to the fluctuation of the load side with the passage of time. There was a risk of remaining. In order to solve this problem, a method has been performed in which another pattern is added to prepare an acceleration table of a pattern with a gentle acceleration, but in this case, a storage area for the added acceleration table is required. It was gone.
[0016]
FIG. 6 is a diagram showing a driving pattern of the carriage during acceleration.
The storage area of the scanner control board 20 stores an acceleration table indicating acceleration patterns (a) and (b) indicated by solid lines in FIG.
The storage area of the scanner control plate 20 stores the number of drive clocks corresponding to the drive speed (PPS) of the motor as one data for each address. The stepping motor 8 can be driven for one step by this one data.
In the acceleration tables of the acceleration patterns (a) and (b) stored in the storage area of the scanner control board 20, the acceleration ends at 700 steps and 800 steps, respectively.
Here, to simplify the description, the acceleration pattern (a) is represented by addresses 0 to 699, and the acceleration pattern (b) is represented by addresses 700 to 1499.
[0017]
The storage area of the scanner control plate 20 is provided with an area for storing a constant-speed drive table, and the constant-speed drive clock number is stored in this area for one data.
In the present embodiment, the number of driving clocks corresponding to the driving speed of 16488 of 100% is stored in this area, and the driving clock at the constant speed calculated with the scaling factor is written at the time of scaling.
In addition, the storage area of the scanner control board 20 is provided with an area for storing a constant speed drive clock during homing.
[0018]
Further, the storage area of the scanner control board 20 is provided with a storage area of an address register Arn (n is an arbitrary integer) indicating an area to be used. With this address register, up to 24 basic drive patterns as shown in FIG. 4 can be set.
For example, when the area of the acceleration pattern (a) is used as it is, the address 0 is written into the address register Ar0, and the address 699 is written into the address register Ar1. As a result, the drive clocks from addresses 0 to 699 are output to the micro-step drive control board, which forms one pattern.
[0019]
In the constant speed portion, since there is no change in the speed, an address indicating the number of drive clocks corresponding to the drive speed 16488 is written in the address register Ar2, and is set as pattern 2.
When the basic driving pattern is divided in this way, the total of the remaining forward deceleration, return acceleration, constant speed, and deceleration is six in total. This division is performed by setting an arbitrary address in the address register Arn.
By using the basic drive pattern division function in this manner, an appropriate acceleration pattern can be created.
[0020]
Next, when the acceleration time in the acceleration pattern (a) shown in FIG. 6 is set to be shorter, the speed is quickly shifted to the constant speed state, and the movement time until the image reading time is increased to suppress the speed fluctuation ( Example 1) will be described.
As shown in FIG. 6, the acceleration can be accelerated by writing a partial address of the acceleration pattern (b) in the address register Arn.
Specifically, the start address 0 of the acceleration pattern (a) is written to the address register Ar0 of the acceleration pattern (a), and the end address 500 is written to the address register Ar1.
Then, the address 1320 of the acceleration pattern (b) which becomes the speed closest to the speed of the driving clock number of the address 500 is written into the address register Ar2 of the acceleration pattern (a), and the end address 1480 is written into the address register Ar3. Write.
Then, a part of the acceleration pattern (a) shown in FIG. 6 is replaced with a part of the acceleration pattern (b), and the acceleration pattern (a) is indicated by a dotted line. By shifting to the constant speed state faster than the previous acceleration pattern (a) and extending the movement time up to the image reading time, it is possible to suppress the speed fluctuation by the start of reading.
[0021]
Next, a description will be given of a method of responding to a case (Example 2) in which, during drive control, a speed fluctuation occurs after shifting to the constant speed state due to excessive acceleration during drive control using the acceleration pattern (a) shown in FIG.
In such a case, control is performed so that the degree of acceleration is slightly reduced.
By writing a partial address of the acceleration pattern (a) in the address register Arn, the degree of acceleration can be reduced.
Specifically, the start address 700 of the acceleration pattern (b) is written to the address register Ar0, and the end address 1000 is written to the address register Ar1.
Then, the address 180 of the acceleration pattern (a) which becomes the speed closest to the speed of the number of drive clocks of the address 1000 of the acceleration pattern (b) is written to the address register Ar2, and the end address 250 is written to the address register Ar3.
Then, a part of the acceleration pattern (b) is replaced with a part of the acceleration pattern (a), and the acceleration pattern (b) is indicated by a dotted line. Since the acceleration becomes gentler than the previous acceleration pattern (b) and becomes constant, the speed fluctuation can be suppressed before the image is read.
[0022]
When the acceleration pattern is used as it is for the deceleration drive in the forward direction, the deceleration drive can be easily realized by writing the start address and the end address of the acceleration table in reverse.
When a drive pattern is used for deceleration driving in the forward direction, deceleration driving can be realized by changing the deceleration pattern in the same manner as during acceleration driving.
Further, when accelerating at a stretch at an automatic frequency as in the case of homing, the drive clock of the self-starting frequency of the stepping motor 8 is written in the constant speed storage area, and the address of the storage area is written in the address register Arn. Only by this, the stepping motor 8 can be started up to the homing constant speed state.
According to the present embodiment, even when the speed of each reading device varies or the inertia (inertia moment) varies, the stepping motor 8 can be stored in a small storage area without changing the control plate on the hardware side. Speed fluctuations.
[0023]
【The invention's effect】
According to the first aspect of the invention, by combining the acceleration table and the constant speed table, it is possible to create an appropriate acceleration table corresponding to the load condition.
According to the invention described in claim 2, by combining the acceleration table and the constant speed table for each part, even when the speed at the constant speed is changed, an acceleration table suitable for the speed can be created. .
According to the third aspect of the present invention, by providing the constant-speed storage area and storing the self-starting frequency therein, the acceleration drive control can be easily performed only by writing the address.
According to the fourth aspect of the invention, by using the acceleration table for driving the carriage of the image reading device, it is possible to provide a drive control device having a small storage capacity and high cost performance.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic configuration of a drive system of an image reading apparatus according to an embodiment.
FIG. 2 is a diagram illustrating a schematic configuration of an image reading apparatus according to the embodiment;
FIG. 3 is a diagram illustrating a schematic configuration of a drive control system of the image reading apparatus according to the embodiment;
FIG. 4 is a diagram showing a basic drive pattern of a carriage.
FIG. 5 is a diagram showing a change in a motor drive pulse during image reading magnification change.
FIG. 6 is a diagram illustrating a driving pattern of a carriage during acceleration.
FIG. 7 is a view showing a driving pattern of a carriage during conventional acceleration.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st carriage 2 2nd carriage 3 Wire 4 Drive shaft 5 Wire pulley 6a-6d Idle pulley 7 Timing belt 8 Stepping motor 9, 10 Timing belt pulley 11 Detecting part 12 Home position sensor 13 Contact glass 14 Exposure lamp 15 First mirror 16 Second mirror 17 Third mirror 18 Imaging lens 19 CCD
20 Scanner control board 21 Micro step drive control board

Claims (4)

Driving means for driving a load;
An accelerating table for instructing acceleration driving of the load in the driving unit, and a storage device for storing a constant speed table for instructing constant speed driving,
Combination of the acceleration table and the constant speed table stored in the storage device, acceleration drive, deceleration drive, or a creating means for creating a drive table to instruct the constant speed drive,
The drive control device, wherein the drive unit controls the drive of the load based on the drive table created by the creation unit. 2. The drive control device according to claim 1, wherein the creating unit changes a portion to be combined between the acceleration table and the constant speed table according to a drive speed of the load. 3. The storage device stores a self-starting frequency for accelerating at a stretch with an automatic frequency,
The driving means uses a stepping motor,
The drive control device according to claim 1, wherein the stepping motor is driven based on the self-starting frequency. 4. The drive control device according to claim 1, wherein the load is a scanning optical system of the image reading device that scans and reads a document of the image reading device.

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