JP5585114B2 - Image reading device - Google Patents

Description

  The present invention relates to a control technique for an image reading apparatus that constitutes a scanner processing unit of a copier or an MFP (Multi Function Peripheral), or a single scanner apparatus.

  In this type of image reading apparatus, the original surface is read by sequentially scanning the original surface in a line in a direction perpendicular to the moving direction while moving the optical system of the reading sensor relative to the fixed original surface. Either a document fixing method for performing the document reading or a document moving method for reading the document surface by moving the document surface with respect to the fixed optical system is employed. The document fixing method is also called an FB (Flat Bed) method, and the document moving method is also called an ADF (Auto Document Feeder) method.

  Also, in this type of image reading apparatus, when reading an image of a document, the image data once read by the image reading unit is written into the memory, and the upper processing unit or an external device (such as a personal computer) is written into the memory. A method of reading the image data is common. Here, the reason for passing through the memory is that the image data reading speed of the image reading unit and the image data reading speed of the host processing unit or an external device do not always match.

  When there is a sufficient memory size for the image data to be read, the image data is continuously written in a predetermined area of the memory, and the upper processing unit or an external device reads the image data from that area of the memory. In this case, the reading operation can be performed without interrupting image reading from the document.

  However, use of a large-capacity memory increases the cost of the apparatus, and therefore, when designing with a minimum cost in mind, it is necessary to limit the memory size to be used. In that case, the memory writes image data in order from the top address of the memory, like a ring buffer, and after writing up to the trailing end address, it returns to the top address again, and the upper processing unit or external device The image data is written in the portion that has become free after the data reading by. In addition, when the data reading operation from the memory by the upper processing unit or an external device is delayed, data cannot be written to the memory area that has not yet been read. Therefore, an image reading operation is performed to prevent memory overflow. Must be performed intermittently.

  In Patent Document 1, when it is determined that the subsequent image data cannot be processed due to the memory full during the image reading operation (the memory has insufficient space), the image reading operation is temporarily stopped. An intermittent image reading technique is disclosed in which an image reading operation is resumed when a free area is generated in the area.

  As described above, in the intermittent image reading operation, the optical system or the document is repeatedly moved and stopped, and the motor that supplies power for movement is repeatedly driven and stopped.

  On the other hand, stepping motors used as motors of this type of image reading apparatus include several phase excitation modes such as a two-phase excitation mode, a 1-2 phase excitation mode, and a W1-2 phase excitation mode even in the case of a two-phase motor. There is. In this type of image reading apparatus, the rotation angle by one pulse of the clock is small, the 1-2 phase excitation mode and the W1-2 phase excitation mode suitable for fine control, and the microstep drive with a smaller rotation angle. In many cases, a micro step motor or the like is used.

  FIG. 1 is a diagram showing an example of an excitation sequence of a stepping motor. In a stepping motor that controls rotation in two phases of A phase and B phase, the reset position is set to “0”, and each clock is counted up. Alternatively, the rotational position of the motor is indicated by a count value that counts down. FIG. 1A shows the positions that the magnetic poles can take in the 1-2 phase excitation mode, FIG. 1B shows the positions that the magnetic poles can take in the W1-2 phase excitation mode, and FIG. The example of the correspondence of a magnetic pole position is shown.

  In the case of the 1-2 phase excitation mode, every time a clock pulse is applied in FIG. 1A, the magnetic pole position is “0” → “1” → “2” → “3” in the case of normal rotation. → “4” → “5” → “6” → “7” → “0”. In case of reverse rotation, “0” → “7” → “6” → “5” → “4” → “3” → Proceed with “2” → “1” → “0”. However, the driving torque at each magnetic pole position is not uniform, and “0”, “2”, “4”, and “6”, which are the two-phase excitation positions, have a larger driving torque than the other magnetic pole positions. Such a stable point having a large driving torque is referred to as a “special stable point”.

  Similarly, in the case of the W1-2 phase excitation mode, every time a clock pulse is given in FIG. 1B, the magnetic pole position is “0” → “1” → “2” → “3” → “4” → “5” → “6” → “7” → “8” → “9” → “10” → “11” → “12” → “13” → “14” → “15 ”→” 0 ”, and in the case of reverse rotation,“ 0 ”→“ 15 ”→“ 14 ”→“ 13 ”→“ 12 ”→“ 11 ”→“ 10 ”→“ 9 ”→“ 8 ”→“ 7 ”→“ 6 ”→“ 5 ”→“ 4 ”→“ 3 ”→“ 2 ”→“ 1 ”→“ 0 ”. Also in this case, the drive torque at each magnetic pole position is not uniform, and the drive torques of “0”, “4”, “8”, and “12” that are the two-phase excitation positions are larger than those of the other magnetic pole positions, and these are special stable points. It becomes.

  FIG. 2 is a diagram illustrating an example of the relationship between the motor rotation speed, the moving distance, and the motor rotation position in intermittent image reading. FIG. 2 shows an example of driving in the 1-2 phase excitation mode, and FIG. In the case of the method, FIG. 2B shows the case of the document moving method. The vertical axis represents the rotational speed of the motor, and the upward direction from the center point is forward (forward), and the downward direction is reverse (backward). The horizontal axis indicates the total distance traveled, and is the total distance traveled regardless of forward or backward travel.

  2A, in the case of the document fixing method, the motor is accelerated in the forward direction from the initial position, and the image reading is performed after shifting to a constant speed. If there is a possibility that the memory becomes full during the image reading process, the vehicle is decelerated and stopped (stop position # 1). Image reading is not performed during deceleration. Subsequently, the switchback is performed in the reverse direction (after the temporary stop, the backward operation for adjusting the reading resume position) to stop (stop position # 2). The stop position # 2 is a position before the position where the deceleration before the stop position # 1 is started (reading stop position) by a distance required for acceleration at the time of restart. Thereafter, when there is no possibility that the memory becomes full, the motor is accelerated again in the forward direction, and the image reading is performed immediately after the previous reading stop position in the state of shifting to the constant speed.

  The reason why the image reading is not performed during acceleration / deceleration is to improve the quality of the read image. For this reason, a switchback operation is necessary after the temporary stop. Therefore, if the image quality is not a problem, it is possible to read an image during acceleration / deceleration (switchback operation is not required). It is not unique to the fixed method.

  In FIG. 2B, in the case of the document moving method, the motor is accelerated in the forward direction from the initial position, and the image reading is performed after shifting to the constant speed only for the first time. If there is a possibility that the memory becomes full during the image reading process, the vehicle is decelerated and stopped (stop position # 1). In this case, image reading is performed even during deceleration. When there is no possibility that the memory becomes full, the motor is accelerated again in the forward direction. In this case, image reading is performed during acceleration, and image reading is continued even after shifting to a constant speed.

  The reason why image reading is performed during acceleration / deceleration except for the first acceleration is that, in the case of the document moving method, paper misalignment occurs during document feeding, and reverse (reverse) control is difficult. However, if the problem of paper misalignment is not taken into account, even in the document moving method, image reading may be performed only at a constant speed, and a switchback operation may be performed at the time of restart. Therefore, whether image reading during acceleration / deceleration is possible and the necessity / requirement of the switchback operation are not unique to the document moving method.

  Here, the motor rotation position at the stop position # 1 in FIG. 2A is “5”, the motor rotation position at the stop position # 2 is “6”, and the stop position # 1 in FIG. The motor rotation positions are “5”, but these motor rotation positions are values determined by chance depending on the timing of the intermittent stop process. In this example, the stop position # 1 “5” in FIG. 2A and the stop position # 1 “5” in FIG. 2B are the special stable points “0” “2” “ Does not correspond to 4 or 6 The stop position # 2 “6” in FIG. 2A coincides with one of the special stable points “0”, “2”, “4”, and “6” in FIG.

  Therefore, in the case of the stop position # 1 “5” in FIG. 2A and the stop position # 1 “5” in FIG. 2B, a stop state in which the next operation must be started from a position that is not the special stable point. Since the driving torque is small and the torque margin is low, there is a risk of causing step-out.

  Stop position # 2 “6” in FIG. 2A accidentally becomes a special stable point, and there is no risk of step-out. However, in the 1-2 phase excitation mode, there is a 1/2 probability other than the special stable point. When the motor is repeatedly driven and stopped under intermittent image reading control, there is always a risk of causing a step-out. Also, in the W1-2 phase excitation mode, there is a 3/4 probability of stopping at a point other than the special stable point, and in a finely controlled microstep motor, there is a higher probability of stopping at a point other than the special stable point, and there is a risk of causing a step-out. Increase.

  In this way, when intermittent image reading control is performed using a motor having a special stable point such as a two-phase excitation position and other stable points, there is a risk of stepping out at each stop and restart. There has been a problem in that the reading position is deviated and the read image is deteriorated.

  The present invention has been proposed in view of the above-described conventional problems, and its object is to perform intermittent image reading control using a motor having a special stable point such as a two-phase excitation position and other stable points. Therefore, an object of the present invention is to provide an image reading apparatus capable of reducing the risk of step-out due to a decrease in torque margin and preventing deterioration of a read image.

In order to solve the above problems, in the present invention, a reading optical system or a reading document is moved using a motor having a special stable point that is an excitation position with a large driving torque and other stable points, An image reading apparatus that performs intermittent image reading control, and when the stop position is not a special stable point during the temporary reading stop deceleration operation of the intermittent image reading operation, a means for performing a correction movement to the special stable point and then stopping, and intermittent Special means during the pause operation as a means to perform the switchback for restarting the reading after pausing the reading and the process of correcting the movement distance corrected to the special stable point during the pausing operation with respect to the moving distance after restarting the intermittent pausing A means for adding the amount of correction movement to the stable point to the switchback distance, and if the stop position is not the special stable point when switching back and stopping, the correction shift is made to the special stable point. The means for stopping after that, the means for comparing the correction value for the special stable point during the pause operation and the correction value for the special stable point during the switchback, and the correction value for the special stable point during the switchback Is equal to or larger than the correction value for the special stable point during the pause operation, the means for performing correction to the special stable point during switchback and the correction value for the special stable point during switchback are temporarily And a means for setting the correction to the special stable point at the time of switchback to a value that becomes the next special stable point when the value is smaller than the correction value to the special stable point during the stop operation .

  In the image reading apparatus of the present invention, even when intermittent image reading control is performed using a motor having a special stable point such as a two-phase excitation position and other stable points, the reading operation is temporarily stopped. Since the excitation position where the acceleration operation of the motor starts is always a special stable point, the risk of step-out due to a decrease in torque margin can be reduced, and deterioration of the read image can be prevented.

It is a figure which shows the example of the excitation sequence of a stepping motor. It is a figure which shows the example of the relationship between the motor rotational speed in a intermittent image reading, a moving distance, and a motor rotational position. 1 is a diagram illustrating a configuration example of an image reading apparatus according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a schematic operation in a configuration example of a reading unit and a document fixing method. FIG. 4 is a diagram illustrating a configuration example of a reading unit and a schematic operation in a document moving method. It is a figure which shows the structural example and basic operation example of a motor control part. 6 is a flowchart illustrating an example of an overall reading operation by an original fixing method. 6 is a flowchart illustrating an example of an entire reading operation by a document movement method. It is a figure which shows the example which matches the stop position at the time of deceleration with a 2-phase excitation position. It is a time chart which shows the example of a motor drive signal production | generation by a motor control part. It is a figure which shows the example which matches the stop position at the time of the switchback in a document fixing system with a 2-phase excitation position. It is a figure which shows the example of control of a reverse rotation stop position. It is a figure which shows the example of position shift correction after the operation | movement start after switchback. It is a figure which shows the example of position shift correction in a document moving system. It is a figure which shows the other example which solves the problem of stopping other than a two-phase excitation position. It is a figure which shows the example of the correspondence of a motor phase excitation position and a deceleration table. It is a figure which shows the structural example of a motor control part. It is a flowchart which shows the process example of an address selection part. It is a figure which shows the other example of a deceleration table. It is a flowchart which shows the process example from a reading temporary interruption instruction | indication to the deceleration start.

  Hereinafter, preferred embodiments of the present invention will be described.

<Configuration and schematic operation>
FIG. 3 is a diagram illustrating a configuration example of the image reading apparatus according to the embodiment of the present invention.

  In FIG. 3, the image reading apparatus 1 includes a reading unit 2 and a controller unit 5.

  The reading unit 2 includes a document setting unit 3 for setting a document and an optical system reading unit 4 for reading the document. The document placing unit 3 and the optical system reading unit 4 are controlled by the controller unit 5, and the optical system reading unit 4 has a function of passing the read image data to the controller unit 5.

  The controller unit 5 includes a reading control unit 6 that controls the reading unit 2, a read image data processing unit 7 that receives image data from the reading unit 2, a buffer memory 8 that stores image data, and a CPU that performs overall control of these units. (Central Processing Unit) 9. The reading control unit 6 and the read image data processing unit 7 are mainly realized by a computer program.

  The reading control unit 6 includes a reading synchronization signal generation unit 61 that generates a reading synchronization signal for the optical system reading unit 4 of the reading unit 2, and a motor control unit 62 that controls the motor of the reading unit 2.

  FIG. 4 is a diagram showing a configuration example of the reading unit 2 and a schematic operation in the document fixing method.

  In FIG. 4, the reading unit 2 includes an apparatus main body 220 and an automatic document feeder 210 disposed on the upper portion of the apparatus main body 220.

  The automatic document conveying unit 210 is provided with a document conveying motor 211 and document conveying rollers 212 and 213.

  A contact glass 221 is provided on the upper surface of the apparatus main body 220, and a first carriage 222, a second carriage 225, a lens 228, a reading unit (CCD: Charge Coupled Device) 229, and a scanner motor 230 are provided therein. Yes. The first carriage 222 is provided with a reading light source 223 and a reading mirror 224. The second carriage 225 is provided with reading mirrors 226 and 227.

  As a general operation, in the case of the original fixing method, the first carriage 222 and the second carriage 225 are moved with a predetermined positional relationship by the scanner motor 230 with respect to the original D to be read placed on the contact glass 221. At this time, light reflected from the original D of the light beam irradiated from the reading light source 223 of the first carriage 222 is sent from the reading mirror 224 to the lens 228 via the reading mirrors 226 and 227 of the second carriage 225, and the reading unit 229. Then, the image for one line in the depth direction in the figure is read.

  FIG. 5 is a diagram showing an example of the configuration of the reading unit 2 and a schematic operation in the document moving method. The internal configuration is the same as that of the reading unit 2 shown in FIG.

  As a general operation, in the case of the document moving method, the first carriage 222 and the second carriage 225 are fixed to the left end side of the apparatus main body 220, and the document D to be read placed on the automatic document transport unit 210 is scanned by the document transport motor. 211 is sent onto the contact glass 221 via the document conveying rollers 212 and 213. At this time, light reflected from the original D of the light beam irradiated from the reading light source 223 of the first carriage 222 is sent from the reading mirror 224 to the lens 228 via the reading mirrors 226 and 227 of the second carriage 225, and the reading unit 229. Then, the image for one line in the depth direction in the figure is read.

  Note that an ARDF (Auto Reverse Document Feeder) with an automatic double-sided reading function can be used instead of the automatic document feeder 210 of FIG. Further, a CIS (Contact Image Sensor) may be used instead of the optical system including the first carriage 222, the second carriage 225, the lens 228, and the reading unit 229.

  FIG. 6 is a diagram illustrating a configuration example and a basic operation example of the motor control unit 62.

  6A, the motor control unit 62 includes a motor pulse generation unit 621, a motor table (memory) 622, a motor driver 623, a motor phase excitation position counter 624, and a two-phase excitation position stop correction value calculation unit 625. I have. The two-phase excitation position stop correction value calculation unit 625 includes a divider 626, an adder 627, and a comparator 628. The motor of the reading unit 2 to be controlled by the motor control unit 62 is the scanner motor 230 in FIG. 4 in the case of the document fixing method, and the document conveyance motor 211 in FIG. 5 in the case of the document movement method.

The motor table 622 stores an acceleration table and a deceleration table. Each stage of the acceleration table and the deceleration table (one block described as “(0100) ₁₆ ” etc. in the figure) corresponds to one pulse of the clock given to the motor, and the period data of the pulse generation by the hexadecimal number etc. Is retained.

  When the motors (230, 211) are accelerated according to the control of the CPU 9 (FIG. 3), the motor pulse generator 621 generates the pulse interval cycle data (interval value) from the acceleration table of the motor table 622 step by step. When reading and decelerating, the cycle data is read from the deceleration table one by one, and a clock impulse or phase pulse signal serving as a motor drive signal to the motor driver 623 is generated. The motor driver 623 receives a clock impulse or phase pulse signal from the motor pulse generator 621, performs signal conversion, and drives the motors (230, 211) of the reading unit 2.

  The motor phase excitation position counter 624 grasps the rotation position of the motor, counts up by 1 every time the motor rotates one step, and returns to 0 by one rotation of the motor. The counter value for one rotation varies depending on the number of phases of the motor, and is, for example, 0 to 7 for 1-2 phase excitation and 0 to 15 for W1-2 phase excitation.

  The two-phase excitation position stop correction value calculation unit 625 inserts how many motor drive pulses to stop at the two-phase excitation position based on the number of stages in the deceleration table and the current value of the motor phase excitation position counter 624. Calculate what.

  FIG. 6B shows a time chart when generating a motor drive signal during deceleration. That is, the motor pulse generation unit 621 uses the interval value preloaded for each pulse from the deceleration table of the motor table 622 as the interval value with a delay of one cycle, and the value of the interval counter based on the clock signal given as the operation clock of the circuit When the signal reaches the interval value, the motor drive signal is switched between H (High level) / L (Low level) to generate a pulse signal having a predetermined period. Since the interval value read from the deceleration table of the motor table 622 gradually increases from the value at the constant speed, the pulse period of the generated motor drive signal becomes longer and the motor speed decreases. When accelerating, the interval value read from the acceleration table of the motor table 622 gradually decreases from the value at the time of stoppage, so the pulse period of the motor drive signal to be generated becomes shorter and the motor speed increases. Go. When the motor is rotated at a constant speed, a constant period motor drive signal is generated by setting the same interval value.

<Detailed operation>
FIG. 7 is a flowchart showing an example of the entire reading operation by the document fixing method.

  In FIG. 7, when image reading is started (step S101), the controller unit 5 accelerates the scanner motor 230 of the reading unit 2 until it reaches a constant speed (steps S102 and S103), and when it reaches a constant speed (step S103). In step S104, the acceleration is stopped and the constant speed operation is started.

  Next, the controller unit 5 starts an image reading process (step S105), and determines whether or not the reading is finished depending on whether or not the end of the reading range has been reached (step S106).

  If the reading is not finished (No in Step S106), the controller unit 5 determines whether or not to enter the reading temporary interruption process due to the memory full (Step S107), and if not entering the reading temporary interruption process (No in Step S107). The process returns to the constant speed operation (step S104).

  When the reading temporary interruption process is started (Yes in step S107), the controller unit 5 temporarily stops the reading process (step S108), and sets the scanner motor 230 of the reading unit 2 to the speed “0” (the lowest speed of the deceleration table). The speed is reduced until the speed reaches (steps S109 and S110), and when the speed reaches "0" (Yes in step S110), the scanner motor 230 is stopped (step S111).

  Next, the controller unit 5 performs a switchback operation (step S112), waits for resumption of reading due to the elimination of the memory full (step S113), and when reading is resumed (Yes in step S113), the scanner motor 230 is accelerated. Return to (Step S102).

  On the other hand, when the reading is completed (Yes in step S106), the controller unit 5 stops the reading process (step S114), and decelerates the scanner motor 230 of the reading unit 2 until the speed reaches “0” (steps S115 and S116). When the speed reaches “0” (Yes in step S116), the scanner motor 230 is stopped (step S117), and the image reading is terminated (step S118).

  FIG. 8 is a flowchart showing an example of the entire reading operation by the document moving method.

  In FIG. 8, when image reading is started (step S201), the controller unit 5 accelerates the document transport motor 211 of the reading unit 2 until it reaches a constant speed (steps S202 and S203). In S203 (Yes), the acceleration is stopped and the constant speed operation is started (step S204).

  Next, the controller unit 5 starts an image reading process (step S205), and determines whether or not the reading is finished depending on whether or not the end of the reading range has been reached (step S206).

  If the reading is not finished (No in Step S206), the controller unit 5 determines whether or not to enter the reading temporary interruption process due to the memory full (Step S207), and if not entering the reading temporary interruption process (No in Step S207). The process returns to the constant speed operation (step S204).

  When the reading temporary interruption process is started (Yes in step S207), the controller unit 5 decelerates the document conveyance motor 211 of the reading unit 2 until the speed reaches "0" (the lowest speed of the deceleration table) (steps S208 and S209). When the speed reaches “0” (Yes in step S209), the document transport motor 211 is stopped (step S210).

  Next, the controller unit 5 waits for resumption of reading due to elimination of memory full (step S211), and when reading is resumed (Yes in step S211), the process returns to the acceleration of the document conveying motor 211 (step S202).

  On the other hand, when the reading is completed (Yes in step S206), the controller unit 5 stops the reading process (step S212), and decelerates the document transport motor 211 of the reading unit 2 until the speed reaches “0” (step S213, In step S214, when the speed reaches "0" (Yes in step S214), the document conveyance motor 211 is stopped (step S215), and the image reading is ended (step S216).

  FIG. 9 is a diagram showing an example in which the stop position at the time of deceleration is matched with the two-phase excitation position, and is control in steps S109 to S111 in FIG. 7 and steps S208 to S210 in FIG. Note that the stop in steps S115 to S117 in FIG. 7 and steps S213 to S215 in FIG. 8 is accompanied by the end of the reading process, and the acceleration is not resumed thereafter, so the stop position is set to the two-phase excitation position. There is no need to match.

  FIG. 9 (a) shows a case of stopping at the two-phase excitation position “6” by rotating one extra pulse at the minimum rotation speed of the motor as shown by r before stopping in the 1-2 phase motor. Show. A broken line indicates a speed change and a stop position when such correction is not performed. In the 1-2 phase motor, since the two-phase excitation position is set every other pulse, when a stop is expected other than the two-phase excitation position, it can be stopped at the two-phase excitation position by adding one pulse.

  FIG. 9B shows a two-phase excitation position “6” in the 1-2 phase motor by rotating an extra one pulse as indicated by r before starting deceleration and then shifting to a deceleration operation. Shows the case of stopping. A broken line indicates a speed change and a stop position when such correction is not performed.

  FIG. 9 (c) shows that the 1-2 phase motor is stopped at the two-phase excitation position “6” by shifting to the decelerating operation after rotating an extra one pulse as indicated by r during deceleration. Shows when to do. A broken line indicates a speed change and a stop position when such correction is not performed.

  FIG. 9 (d) shows a two-phase excitation position “12” in the W1-2 phase motor by rotating to the decelerating operation after rotating an extra two pulses as indicated by r1 and r2 during deceleration. Shows the case of stopping. A broken line indicates a speed change and a stop position when such correction is not performed. In the W1-2 phase motor, the two-phase excitation position is set every three pulses, so if a stop is expected other than the two-phase excitation position, it can be stopped at the two-phase excitation position by adding pulses 1 to 3. it can. In addition, you may combine with the method of Fig.9 (a) and FIG.9 (b).

  By stopping at the two-phase excitation position in this way, it is possible to always start from the two-phase excitation position when the motor starts to move again, so that step-out due to a decrease in torque margin can be prevented, and thus the read image is deteriorated. Can be prevented.

  FIG. 10 is a time chart showing an example of generation of a motor drive signal by the motor control unit 62 (FIG. 6). FIG. 10A shows a case where correction is made to make the stop position the two-phase excitation position immediately before stopping, and FIG. 10B shows a case where correction is made to make the stop position the two-phase excitation position before starting deceleration. It is an example.

In FIG. 10A, when the preloader reads the termination value “(FFFF) ₁₆ ” of the deceleration table immediately before the deceleration stop, the motor pulse generation unit 621 looks at the motor phase excitation position counter 624 to determine the next counter value. If is not a two-phase excitation position, control is performed so that the interval value is not updated until the next value reaches the two-phase excitation position. Thereby, it is possible to control so that the stop position is always the two-phase excitation position. In the figure, in the case of the W1-2 phase excitation motor, the counter value of the motor phase excitation position counter 624 when the preloader reads “(FFFF) ₁₆ ” is “5”. The interval value is not updated until the counter value becomes “7” so that it can be stopped at “8”.

In FIG. 10B, the motor pulse generator 621 receives a motor deceleration start instruction from the CPU 9.
(Remainder of ([Motor deceleration table step number] / [Phase excitation counter value for one motor rotation]))
+ [Current value of motor phase excitation position counter]
Is calculated using the divider 626 and the adder 627 of the two-phase excitation position stop correction value calculation unit 625, and the difference with respect to the next two-phase excitation position is calculated by the comparator 628. For example, if the motor deceleration table stage number is “34”, the phase excitation counter value for one rotation of the W1-2 phase excitation motor is “16”, and the current value of the motor phase excitation position counter is “2”,
35/16 = 2... 3 ⇒ 3 (remainder) +2 (current counter value) = 5
Is calculated. And since the next two-phase excitation position is “8”, the difference up to that 8−5 = 3
Is calculated without changing the interval value for 3 pulses before starting deceleration, and then the operation proceeds to deceleration operation, so that the stop position becomes the two-phase excitation position.

  FIG. 11 is a diagram showing an example in which the stop position at the time of switchback in the document fixing method is matched with the two-phase excitation position. FIG. 11A shows the case where the stop position is not corrected for comparison, FIG. b) is an example when the stop position is corrected. In the case of the document moving method, the backward operation by the switchback is generally not performed, so the description here is unnecessary. However, even in the document moving method, when the backward control is performed after the temporary stop, the control described here can be used.

  In FIG. 11A, in the case of the document fixing method, the reading carriages (222, 225) move as indicated by arrows with respect to the fixed document D. When paused by intermittent image reading, the carriage is moved backward from the paused position P1 by [distance required for deceleration] + [distance required for acceleration] so that reading can be resumed from the position where deceleration was started. Stops at the position P2, and acceleration is restarted by restarting reading.

  In FIG. 11B, when the correction is performed, if the stop position P1 before the correction is not the two-phase excitation position of the motor, the motor moves forward by the two-phase excitation position correction and stops at the position P1 ′. At this point, the stop position P2 when the reverse travel distance of the carriage is [distance required for deceleration] + [distance required for acceleration] is insufficient to restart reading from the position where deceleration is started. Therefore, it is necessary to add the amount of movement moved by the two-phase excitation position correction from the position P1 to the position P1 ′ at the time of reverse travel, and the stop position is P2 ′.

  Further, when the stop position P2 ′ is not the two-phase excitation position, the actuator moves backward by an amount corresponding to the two-phase excitation position correction and stops at the position P2 ″.

  In the above operation, if the two-phase excitation position correction value from the position P1 to the position P1 ′ is X and the distance from the position P2 to the closest reverse-side two-phase excitation position is Y, if X ≦ Y, reverse Sometimes two-phase excitation position correction similar to that described above may be performed. This state is shown in FIG.

  In addition, when X> Y, in the two-phase excitation position correction at the time of reverse travel, the two-phase excitation position that is one step ahead of the foremost two-phase excitation position (the position used as the normal two-phase excitation position correction) The correction movement may be performed. This state is shown in FIG. That is, correction corresponding to YY is performed.

  Thus, at the time of the reading restart operation after the switchback, the motor is driven from the two-phase excitation position, and [the distance required for acceleration] + [2] with respect to [the position where deceleration is started (position where reading is restarted)] Since the phase excitation position correction] is ensured, reading can be resumed in a constant speed state after the acceleration is completed.

  With the above operation, the stop position of the motor can be set to the two-phase excitation position, and the resumption of the motor operation when the reading is resumed always starts from the two-phase excitation position. However, since this is a temporary stop during the image reading operation, the read image is displaced by the amount of movement of the motor that has rotated excessively to stop at the two-phase excitation position between the deceleration and the stop. That is, the reading restart position is set from the distance required for acceleration by starting the operation from the pause position of the reading operation, and the reading operation is started from there. However, since there is a deviation from the position of the image to be read by Z by the two-phase excitation position correction, the read image and the image data to be actually read become image data shifted by Z. Therefore, it is necessary to correct the reading position deviation caused by the two-phase excitation position correction during deceleration during the reading restart operation.

  FIG. 13 is a diagram showing an example of positional deviation correction after the start of operation after switchback in the document fixing method.

FIG. 13A shows a case where no positional deviation correction is performed for comparison, and the reading restart position is shifted forward by Z with respect to the original position of the read image. The positional deviation amount Z includes the distance from the advance start position P2 in FIG. 11 (a) to [position where reading is to be resumed] and the advance start position P2 ″ in FIG. 11 (b) [position where reading is desired to resume]. More specifically, in the case of FIG.
Z = Y-X
In the case of FIG.
Z = YY-X
It becomes.

  FIG. 13B shows a case where positional deviation correction is performed at the start of acceleration. The positional shift amount Z can be obtained in advance from the above formula, and after moving the correction amount at the slowest speed (first speed of the acceleration table) that is not “0” at the start of motor operation, acceleration is performed. By starting, it is possible to perform positional deviation correction. The position of the original read image coincides with the reading restart position by this positional deviation correction.

  FIG. 13C shows a case where the acceleration from the start of the operation is normally performed without correction, and the positional deviation correction is performed after shifting to the constant speed operation.

  FIG. 13D shows a case where positional deviation correction is performed in two stages during acceleration. In this case, the first correction amount Z1 and the second correction amount Z2 have a relationship of Z = Z1 + Z2.

  Moreover, you may combine the position shift correction | amendment of FIG.13 (b) (c) (d).

  FIG. 14 is a diagram showing an example of positional deviation correction in the document movement method. In the case of the document moving method, since there is no backward movement and all the movements during acceleration / deceleration are counted as movements for image reading, the movement r for the two-phase excitation position correction that occurs during the temporary stop is fixed in the operation after resuming reading. It can be corrected by subtracting from the fast moving part. A broken line indicates a speed change when the two-phase excitation position correction is not performed.

  With the above control, when temporary reading is stopped in the intermittent image reading operation, the motor operation is always restarted from the two-phase excitation position, and deviation of the read image position due to the correction can be suppressed.

  FIG. 15 is a diagram showing another example for solving the problem of stopping other than the two-phase excitation position. In other words, it is a method different from the one described above, and when stopping, it stops without considering the two-phase excitation position, and when the operation resumes, it moves to the two-phase excitation position at the lowest speed and then starts the acceleration operation. is there. If the motor is temporarily stopped at a position other than the two-phase excitation position, a step-out due to a decrease in torque margin becomes a problem. However, in this control, the motor has already started operating before reaching the two-phase excitation position where acceleration should be started. Even if the acceleration is not necessarily from the two-phase excitation position, which is a stable point, acceleration can be performed without causing problems such as step-out, and an effect close to that of the above-described method can be obtained. In this case, in general, there is an advantage that the circuit scale required for the control can be reduced as compared with the above-described control. An operation that operates from a place other than the two-phase excitation position and starts moving at a low speed and then shifts to an acceleration operation is referred to as an acceleration operation by running.

  When the acceleration is started from the two-phase excitation position and when the torque margin is small as a method for separating the acceleration operation by the run-up, the two-phase excitation position is set in a relatively small step like the 1-2 phase motor or the W1-2 phase motor. When using a coming motor, control is performed to start acceleration from the two-phase excitation position, and when using a micro-step motor, the distance from the two-phase excitation position to the next two-phase excitation position is, for example, 6 In the case of the above, the amount of movement required for correction can be reduced by controlling by the acceleration operation by the running. In the acceleration operation by running, the control circuit can be further simplified by determining the moving amount by running to a fixed amount.

  Next, a method of correcting the stop position to the two-phase excitation position in the same manner as described above with the configuration without the two-phase excitation position stop correction value calculation unit 625 in FIG. 6 will be described.

  In FIG. 1A, considering the relationship from each rotational position to the nearest two-phase excitation position, the two-phase excitation positions “0”, “2”, “4”, “6”, and two-phase movement by one step movement There are two types, “1”, “3”, “5”, and “7”, which are excitation positions. In the case of FIG. 1B, similarly, the two-phase excitation positions “0”, “4”, “8”, and “12” and the forward rotation 1 step (reverse rotation 3 steps) move to the two-phase excitation position. “3”, “7”, “11”, “15”, and “2”, “6”, “10”, “14” that become the two-phase excitation position by two-step movement, and three forward rotation (one reverse rotation) movement There are four types of "1", "5", "9", and "13" that are two-phase excitation positions.

  Considering the intermittent stop operation with respect to FIG. 1A, the motor table 622 of FIG. 6 has rotational positions “0”, “2”, “4”, and “6” for two-phase excitation as shown in FIG. ”And when the stop operation is started from the rotational positions“ 1 ”,“ 3 ”,“ 5 ”, and“ 7 ”, the position where each stops is the two-phase excitation position. Prepare two kinds of deceleration tables. Similarly, in the case of FIG. 1B, four kinds of deceleration tables as shown in FIG. 16B are prepared. The configuration of the deceleration table is performed in accordance with the deceleration pattern for performing position correction shown in FIG. It does not ask which pattern of Fig.9 (a)-(d).

  FIG. 17 is a diagram illustrating a configuration example of the motor control unit 62. The motor pulse generation unit 621 or a register from which the motor pulse generation unit 621 can read the start address of the deceleration table corresponding to each phase excitation position in the motor table 622. The address selection unit 629 outputs an address signal and reads data from the motor table 622. When entering the reading temporary interruption process of FIG. 7 and FIG. 8 (Yes in step S107 in FIG. 7 and Yes in step S207 in FIG. 8), the deceleration table is selected based on the rotational position information at the time of starting deceleration. .

  FIG. 18 is a flowchart illustrating a processing example of the address selection unit 629. That is, when the address selection unit 629 starts processing (step S301), the value of the motor phase excitation position counter 624 is confirmed (step S302), and the deceleration table start address corresponding to the motor phase excitation position is selected (step S303). ). Thereby, address selection is completed, and deceleration is started according to the selected deceleration table (step S304). Since the deceleration table is selected so that it can stop at the two-phase excitation position in accordance with the phase excitation position (rotation position) of the motor to start deceleration, the stop position becomes the two-phase excitation position.

  In the case of reading by the document fixing method, the switchback operation table to be performed later is prepared in advance in the same manner as the deceleration table in accordance with the phase excitation position (rotation position) of the motor at the start of deceleration. By selecting and using according to the result, the stop position of the motor can be set to the two-phase excitation position, and the reading restart position can be performed from the reading temporary interruption position.

  In the above-described method of preparing a deceleration table for each rotational position of the motor, the deceleration table can be divided into a moving part for correcting to the two-phase excitation position and a part for decelerating. And the part which decelerates can be made common regardless of a rotation position. This corresponds to the “r” portion of the deceleration operation in FIG. 9 and the other deceleration operation portions.

  Therefore, only the portion “r” in FIG. 9 is selected according to the motor rotation position at which the intermittent stop operation is started, and the tables of the other deceleration operation portions are made common, thereby saving the memory of the motor table 622. it can. FIG. 19 shows an example of a motor table 622 including a deceleration table having such a configuration.

  On the other hand, as another correction method, a method of fixing the phase excitation position at which deceleration starts will be described.

  When performing deceleration using a certain deceleration table from a certain constant speed movement speed, in order to set the stop position to the two-phase excitation position, the phase excitation position at which deceleration is started is determined as one. However, since there are four two-phase excitation positions in the motor, there are four deceleration start positions as relative positions from the two-phase excitation position. Taking FIG. 1B as an example, when it is necessary to set the deceleration start position to “13” in order to stop at the two-phase excitation position “0”, the two-phase excitation positions “4”, “8”, “ “1”, “5”, and “9” respectively correspond to the deceleration start positions that stop at “12”.

  In this method, when the reading temporary interruption process is started, the phase excitation position is “1”, “5”, “9” under the conditions of the above example, wherever the phase excitation position of the motor is at that point. ”Continues constant speed movement until either“ 13 ”is reached, and then starts decelerating. By such an operation, the excitation position of the motor at the stop position can be corrected to the two-phase excitation position.

  As a result, waiting for the deceleration start at the time of the temporary reading interruption until any of the phase excitation positions “1”, “5”, “9”, “13” is corrected from the reading temporary interruption processing start instruction to the deceleration start. It is moving, and the correction movement should be as short as possible. For this reason, the correction movement is performed by selecting an excitation position (“1”, “5”, “9”, “13” in the above example) that can be stopped to the nearest two-phase excitation position after receiving the instruction to temporarily stop reading. Minimize.

  On the contrary, in order to facilitate the processing, it is possible to employ a configuration in which deceleration is always started from one excitation position without using four excitation positions as in the above example. As a result, the correction movement amount is wasted, but the control circuit can be simplified. For example, in the case of the above example, no matter where a temporary reading interruption instruction can be given, the deceleration start is always fixed at the excitation position “13”, thereby controlling the stop position to the two-phase excitation position “0”. Do.

  FIG. 20 is a flowchart showing an example of processing from the reading suspension instruction to the start of deceleration. That is, when there is an instruction to temporarily stop reading (step S401), it is determined whether or not it is an excitation position at which deceleration starts (step S402). If it is not the excitation position for starting deceleration (No in step S402), the motor is moved by one step (step S403), and the process returns to the determination (step S402) as to whether the excitation position is for starting deceleration. When the excitation position for starting deceleration is reached (Yes in step S402), deceleration is started (step S404).

<Summary>
As described above, according to this embodiment, even when intermittent image reading control is performed using a motor having a special stable point such as a two-phase excitation position and other stable points, the reading operation is temporarily performed. Since the excitation position where the acceleration operation of the motor starts after stopping is always a special stable point, it is possible to reduce the risk of step-out due to a decrease in torque margin and to prevent deterioration of the read image.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Reading unit 210 Automatic document conveying part 211 Document conveying motor 212 Document conveying roller 213 Document conveying roller 220 Apparatus main body part 221 Contact glass 222 First carriage 223 Reading light source 224 Reading mirror 225 Second carriage 226 Reading Mirror 227 Reading mirror 228 Lens 229 Reading unit 230 Scanner motor 3 Document placement unit 4 Optical system reading unit 5 Controller unit 6 Reading control unit 61 Reading synchronization signal generation unit 62 Motor control unit 621 Motor pulse generation unit 622 Motor table 623 Motor driver 624 Motor phase excitation position counter 625 Two-phase excitation position stop correction value calculation unit 626 Divider 627 Adder 628 Comparator 629 Address selection unit 7 Read image data processing unit 8 Buffer memory 9 CPU
D Manuscript

Japanese Patent No. 3701621

Claims (16)

An image reading apparatus that performs intermittent image reading control by moving a reading optical system or a reading document by using a motor having a special stable point that is an excitation position with a large driving torque and other stable points,
If the stop position is not a special stable point during the deceleration operation of the temporary reading stop of the intermittent image reading operation, a means for performing a correction movement to the special stable point and then stopping,
Means for performing a switchback for resuming the reading after pausing intermittent reading;
Means for adding the amount of correction movement to the special stable point during the pause operation as a process for correcting the movement distance after restarting the intermittent stop as a process for correcting the movement distance after the restart of the intermittent stop. ,
If the stop position is not the special stable point when switching back and stopping, means for stopping after the correction movement to the special stable point,
Means for comparing the correction value to the special stable point during the pause operation and the correction value to the special stable point at the time of switchback;
Means for performing correction to the special stable point at the time of switchback as it is when the correction value to the special stable point at the time of switchback is equal to or larger than the correction value to the special stable point at the time of the pause operation;
When the correction value to the special stable point at the time of switchback is smaller than the correction value to the special stable point at the time of the pause operation, the correction to the special stable point at the time of switchback becomes the next special stable point. An image reading apparatus comprising: means for converting into a value . The image reading apparatus according to claim 1,
When the scheduled stop position during deceleration operation is not the special stable point, the image is read by performing constant speed movement to the special stable point at the lowest speed immediately before stopping and adjusting the stop position to be the special stable point. apparatus. The image reading apparatus according to claim 1, wherein:
An image reading apparatus that adjusts the start position of deceleration so that the stop position becomes a special stable point when the planned stop position during the deceleration operation is not a special stable point. The image reading apparatus according to any one of claims 1 to 3,
An image reading apparatus characterized in that, when a planned stop position during a deceleration operation is not a special stable point, a constant speed movement is performed during deceleration and adjustment is performed so that the stop position becomes a special stable point. The image reading apparatus according to any one of claims 1 to 4,
An image reading apparatus that performs constant speed movement at a minimum speed after restarting intermittent stop and corrects the amount of correction movement to a special stable point during a pause operation. In the image reading device according to any one of claims 1 to 5,
An image reading apparatus that performs constant speed movement during constant speed operation after completion of acceleration after restarting intermittent stop and corrects the amount of correction movement to a special stable point during temporary stop operation. The image reading apparatus according to any one of claims 1 to 6,
An image reading apparatus, wherein the acceleration operation is interrupted during the acceleration operation after restarting the intermittent stop, the constant speed movement is performed, and the amount of correction movement to the special stable point during the pause operation is corrected. In the image reading device according to any one of claims 1 to 7,
A deceleration table that stops at a special stable point is provided for each excitation position where motor deceleration starts.
An image reading apparatus that performs correction movement to a special stable point during a pause operation and performs a deceleration operation by selecting a corresponding deceleration table from motor excitation position information at the time of the pause operation start. The image reading apparatus according to claim 8 .
The deceleration table is divided into a table for correction movement to a special stable point and a table for deceleration,
An image reading apparatus using a table for deceleration in common. The image reading apparatus according to any one of claims 8 and 9 ,
A table for switchback operation, which is added to the distance to switch back the amount of correction movement to the special stable point during the pause operation, is provided for each excitation position at which the motor deceleration starts,
From the excitation location information of the temporary stop operation at the start of the motor, intends row switchback operation for resuming reading after the pause of the read intermittently select a table for switchback
Image reading device comprising a call. The image reading apparatus according to claim 10 .
For correction movement to the special stable point, a table for switchback operation, which is provided for each excitation position where the motor starts to decelerate, is added to the distance for switching back the amount moved to the special stable point during the temporary stop operation. And the table for the switchback operation,
An image reading apparatus using a table for performing a switchback operation in common. The image reading apparatus according to any one of claims 9 and 11 ,
An image reading apparatus using a table for correction movement before and after a deceleration operation of a motor. In the image reading device according to any one of claims 1 to 7,
An image reading apparatus that fixes a phase excitation position of a motor that starts deceleration during a pause operation. The image reading apparatus according to claim 13 .
An image reading apparatus comprising a switchback operation table configured to correct in advance a movement amount that is the largest amount of movement to a fixed phase excitation position that starts deceleration during a pause operation. A control method of an image reading apparatus that performs intermittent image reading control by moving a reading optical system or a reading document using a motor having a special stable point that is an excitation position with a large driving torque and other stable points. ,
If the stop position is not the special stable point during the deceleration operation of the temporary reading stop of the intermittent image reading operation, a step of performing a correction movement to the special stable point and then stopping,
A step of performing a switchback for resuming reading after pausing intermittent reading;
As a process of correcting the amount corrected to the special stable point during the pause operation with respect to the movement distance after restarting the intermittent stop , a step of adding the amount corrected to the special stable point during the pause operation to the switchback distance; and ,
When the stop position is not a special stable point when switching back and stopping, a step of performing a correction movement to the special stable point and then stopping,
A step of comparing the correction value to the special stable point during the pause operation and the correction value to the special stable point during the switchback;
When the correction value to the special stable point at the time of switchback is equal to or larger than the correction value to the special stable point at the time of the pause operation, the process of correcting the special stable point at the time of switchback as it is,
When the correction value to the special stable point at the time of switchback is smaller than the correction value to the special stable point at the time of the pause operation, the correction to the special stable point at the time of switchback becomes the next special stable point. the image reading control method comprising the <br/> the step of the value. A control program for an image reading apparatus that performs intermittent image reading control by moving a reading optical system or a reading document using a motor having a special stable point that is an excitation position with a large driving torque and other stable points. ,
A computer constituting the control unit of the image reading apparatus;
Means for stopping after the correction movement to the special stable point when the stop position is not the special stable point during the deceleration operation of the temporary reading stop of the intermittent image reading operation;
Means for performing a switchback for resuming the reading after the intermittent reading is temporarily stopped;
Means for adding the amount of correction movement to the special stable point during the pause operation as a process for correcting the movement amount corrected to the special stable point during the pause operation with respect to the movement distance after restarting the intermittent stop ,
If the stop position is not a special stable point when switching back and stopping, a means to make a correction movement to the special stable point and then stop,
Means for comparing the correction value to the special stable point during the pause operation with the correction value to the special stable point during switchback;
A means for correcting the special stable point at the time of switchback as it is when the correction value to the special stable point at the time of switchback is equal to or larger than the correction value to the special stable point at the time of pause operation,
When the correction value to the special stable point at the time of switchback is smaller than the correction value to the special stable point at the time of the pause operation, the correction to the special stable point at the time of switchback becomes the next special stable point. An image reading control program that functions as a means for obtaining a value .

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