JPH08186690A - Picture reader - Google Patents

Abstract

PURPOSE: To lighten the burden of software processing to be imposed at the time of slow-up/slow-down. CONSTITUTION: The tables of the slow-up/slow-down to be used at the time of driving and stopping a reading sensor are stored in a ROM 19 in which a program related to an MPU 14 to control collectively the whole device. That tables use all of driving frequency except stationary driving maximum frequency and the driving frequency for starting stationary driving minimum frequency. They are stored in such form that they are arranged in order from the low frequency in the case of the slow-up, and in such the form that they are arranged in order from the high frequency in the case of the slow-down. Then, slow-up operation is executed by reading the part of the slow-up/slow-down tables out of the ROM 19 by the MPU 14, and transferring it to a machanism control part 16, and driving a motor by the mechanism control part 16 on the basis of the data of the table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus to which a book scanner type image reading section is applied.

[0002]

2. Description of the Related Art In general, most of current facsimile machines have a mechanical system in a reading section and a recording section, and the structure of the reading section of this type of facsimile machine is either a sheet-through type or a book scanner type. Many tend to adopt. In addition, a book scanner type is often used for a multifunction machine having a facsimile function, a copying function, and the like because it is considered to be applied to copy / transmission of a document such as a book that cannot be read by a sheet-through type.

Further, when the multi-functional peripheral is regarded as a facsimile machine, it is premised that intermittent driving is performed.
It is necessary to use a synchronous motor, and there are many examples in which a stepping motor is used because of its ease of handling, cost merit, and the like.

When some kind of driving unit is moved by using a stepping motor, slow-up / slow-down is often used in order to prevent step-out, noise, etc., and many inventions related to this have been made conventionally (for example, There are many examples in which slow-up / slow-down are actually performed in the motor drive sequence in the product).

When the multi-function peripheral is regarded as a copying machine, there are many examples having a variable-magnification copying function as one of its functions. When changing the magnification, in the main scanning direction, the size is reduced / set by setting the conditions of the reading reduction optical system or software image processing.
There are many cases in which enlargement processing is performed. For scaling in the sub-scanning direction, scaling can be performed by fixing the sensor reading interval per line and changing the drive speed of the reading sensor or the mirror in the preceding stage. Many (move the sensor quickly when you want to reduce it, move slowly when you want to enlarge it). Therefore, the stepping motor, which is the drive source, is driven at various speeds.

In this case, the slow-up / slow-down setting is performed by storing a large number of tables for each frequency in a storage device such as a ROM and reading the tables at the time of starting / stopping each frequency. A method is used in which a pulse to be performed is created by software, and the created pulse is sent to a motor for driving.

[0007]

However, when such driving is performed, since the driving is performed while replacing the reference table for each frequency, the load of software processing becomes large, and the ROM area for the table becomes large. Problems such as large size are possible.

Further, in the case of a book scanner type facsimile apparatus, drive is often transmitted from a motor to a moving body (sensor, mirror, etc.) by a belt or a wire. In this case, the friction tends to be smaller with respect to the inertia, and the elastic term in the drive transmission system is large. When abrupt acceleration is performed, the potential is accumulated in the drive transmission system at the initial stage of startup, and after a certain time, There is a high possibility that the potential is discharged all at once and a damping vibration term is added to the t-ω characteristic of the moving body.

Further, if the intermittent driving is performed in such a state, it is considered that the image reading becomes defective at each intermittent timing and the read image quality is deteriorated. In this case, it is conceivable to use additional inertia or the like, but there are many cases in which the opposite effect is obtained.

It is an object of the present invention to provide an image reading apparatus which solves such a problem, and realizes the minimization of a table storage area while maintaining the merit of performing slow-up / slow-down.

[0011]

In order to achieve the above object, the present invention provides a reading unit for reading an image while moving with respect to a fixed document, a stepping motor as a driving source for the reading unit, and the stepping motor. In an image reading apparatus provided with a storage unit for storing a plurality of motor drive frequencies for performing various speed changes and driving the motor in stages,
The storage means is provided with a slow-up table in which a plurality of the motor drive frequencies are arranged as elements in order to perform a slow-up at the time of startup, and when starting the stepping motor, a motor having a frequency equal to or lower than a target frequency on the slow-up table is provided. It is characterized by further comprising control means for switching from slow-up control to control for applying a steady drive pulse when the target frequency is reached, using the drive frequency.

Further, a reading unit for reading an image while moving with respect to a fixed document, a stepping motor serving as a driving source for the reading unit, and a plurality of stepping motors for performing various speed changes to drive the stepping motor in stages. In the image reading apparatus having a storage means for storing the motor drive frequency, the storage means is provided with a slowdown table in which a plurality of the motor drive frequencies are arranged as elements in order to perform a slowdown at the time of stop. When stopping, the motor drive frequency corresponding to the frequency below the target frequency on the slowdown table is used to start the slowdown operation, and stop driving the stepping motor when the end of the slowdown table is reached. It is characterized in that a control means for controlling is provided.

Further, a reading unit for reading an image while moving with respect to a fixed document, a stepping motor serving as a driving source of the reading unit, and a plurality of stepping motors for performing various speed changes and driving them stepwise. In the image reading apparatus having a storage unit for storing the motor driving frequency, a stepping motor is used as a driving source of the reading unit, and the acceleration operation is performed more slowly than the slow-up operation required to start the stepping motor. It is characterized in that the motor drive system used for control is provided with control means for performing control for driving at a lower current value than in the case of performing steady drive operation in the initial stage of slow-up.

Further, the table is characterized in that the table in which the motor drive frequencies used during gear shifting are arranged in order from the lower one to the higher one is a slow-up table.

Further, it is characterized in that a table in which the motor drive frequencies used during gear shifting are arranged in order from the highest to the lowest is a slowdown table.

[0016]

According to the above construction, all the motor drive frequencies used during gear shifting are continuously arranged, whereas a plurality of tables are conventionally soft-selected to perform slow-up / slow-down operations. Since the table is used for slow-up / slow-down operation, the number of tables to be read is reduced and the load of software processing is reduced.

Further, in the initial stage of the slow-up, by controlling to drive with a lower current value than that in the case of performing the steady drive state, stepping out, noise, and vibration due to the excessive output torque of the motor with respect to the initial load of starting the stepping motor. Can be avoided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a facsimile apparatus according to an embodiment of the present invention, in which 1 is a reading unit and 2 is a recording unit. The reading unit 1 is composed of a reading scanning unit 3, a reading processing unit 4, a line memory 5 and a line memory control unit 6, and a recording unit 2 is a recording scanning unit 7, a recording processing unit 8, a line memory 5 and a line memory control unit. It is composed of a part 6. Note that FIG. 1 shows an example of a full-duplex configuration.

The image information read by the reading scanning unit 3 is
It is temporarily stored in the line memory 5 via the reading processing unit 4.
Next, according to the mode of the information compression / decompression unit 9, the redundancy is removed while reading the image information from the line memory 5, and the redundancy is stored in the RAM 10 through the data bus. This R
The communication control unit 11 is used again by using the AM10 as a transmission buffer.
To the modem 12 via. The signal modulated by the modem 12 is sent out to the line through the network control unit 13.

On the contrary, the image information received from the line passes through the network control unit 13, is demodulated by the modem, is output to the data bus via the communication control unit 11, and is stored in the RAM 10. This R
The AM 10 is used as a reception buffer and is sequentially input to the information compression / decompression unit 9 via the data bus. further,
The image information restored under the control of the line memory controller 6 is sent to the line memory 5. Then, it is called from the line memory 5 again, passes through the recording processing unit 8 and then the recording scanning unit 7
Is reproduced as image information.

The image information simply passes through the network control unit 13 and the communication control unit 11, but the communication control information is read and understood in the communication control unit 11 to execute transmission control, error control, etc. Processing is performed, and when journal information is required, it is stored in the RAM 10 having a non-volatile function.

A call signal for controlling the network is controlled by the network controller 13. Further, the image information that does not require information compression and decompression can be directly taken out from the reading processing unit 8 and the line memory 5 to the outside such as the RAM 10 via the data bus for image processing or image communication. Further, it is also possible to directly input the image-processed information or the image-synthesized information to the line memory 5, or to superimpose the image information and then store it in the line memory 5 for storage and reproduction.

The line memory 5 can be used separately from the information compressing / decompressing unit 9, and at the same time, a mode of use in which the compressed information is decompressed irrespective of reading scanning and is output via the line memory 5 is also conceivable. In addition, the overall system control,
The MPU 14 performs overall control such as information flow management, communication control, and network control.

The main processing of system control is the panel unit 15
Control related to the man-machine interface by
The control is related to the mechanical configuration of the reading unit 1 and the recording unit 2 by the mechanism control unit 16.

The number of input terminals and the control system of the panel unit 15 are greatly different depending on the type and form of panel switch and panel display. Further, the mechanism control unit 16 changes the type and quantity of the driver and the sensor depending on the method and mechanical configuration of the reading unit 1 and the recording unit 2, and affects the control complexity.

In FIG. 1, 17 is a power source unit and 18 is D
MA (Direct Memory Access) controller, 19 is MPU
14 shows a ROM in which 14 control programs are stored.

FIG. 2 is a plan view of the inside showing the schematic construction of the reading unit (book scanner type) of the facsimile apparatus of this embodiment, FIG. 3 is a side view of FIG. 2, 20 is a stepping motor, and 21 is a timing belt. , 22 is a transmission pulley, 23 is a drive wire, 24 is a facing pulley, 25 is a reading sensor, 26 is a guide rail, and 27 is a scanner base.

The transmission pulley 22 is driven by transmitting the driving force from the stepping motor 20 serving as a drive source to the transmission pulley 22 by the timing belt 21. A drive wire 23 is hung on the transmission pulley 22, and the drive wire 23 is stretched in the longitudinal direction of the guide rail 26 by the transmission pulley 22 and the opposing pulley 24. Therefore, when the transmission pulley 22 is driven, the drive wire 23 starts circulating movement, and in conjunction with this, the driving force is transmitted to the reading sensor 25 fixed to the driving wire 23, and the reading sensor 25 moves.
Both ends of the reading sensor 25 are in contact with the guide rail 26, and the weight of the reading sensor 25 is applied to the guide rail 26.
When moving, it slides on the guide rail 26. The drive control of the stepping motor 20 is performed by the mechanism control unit.
16 (see FIG. 1).

By the way, as described in the section of the prior art, when moving some driving portion using the stepping motor, slow up / slow down is often used to prevent step-out, noise and the like.

FIG. 4 is an actual measurement diagram showing an example of a conventional general slow-up condition. The horizontal axis represents time, and the vertical axis represents angular velocity of the transmission pulley. FIG. 5 is an actual measurement diagram showing a speed curve of the reading sensor when the drive shown in FIG. 4 is performed. In addition, FIG.
Is an actual measurement diagram of the speed curve of the transmission pulley when several slow-ups are first performed, and the horizontal axis represents time and the vertical axis represents the angular speed of the motor pulley. FIG. 7 is an actual measurement diagram showing a velocity curve of the reading sensor when the drive shown in FIG. 6 is performed.

The motor itself can be started with several slow-up pulses as shown in FIG. 6 if it is a system like the configuration example shown in FIGS. 2 and 3, but as shown in FIG. As described above, there is a possibility that the hunting becomes large and the read image is deteriorated. Therefore, many slow-ups are often performed as shown in FIG. 4, and by doing so, hunting is reduced as shown in FIG.

Next, the slow-up operation according to this embodiment will be described.

FIG. 8 is an explanatory diagram showing a slow-up table stored in the ROM. For the sake of explanation,
Here, the frequencies for steady drive are 500, 750, 1000,
Assume a system using 2000, 2500 PPS. This slow-up table shows the drive frequencies other than the steady drive maximum frequency (here, 2500PPS) and the steady drive minimum frequency (here, 500PPS).
Using all the drive frequencies for starting S), as shown in FIG. 8, it is one table in which the excitation pulses are connected in the order of 375, 500, 750, 1000, 2000 PPS. In addition,
The driving time at each frequency is set to be a predetermined time at the time of design.

For example, when starting at 2000 PPS, the frequency below 2000 PPS on the slow-up table,
Here, the range of 375,500,750,1000PPS is read, and the drive frequency is gradually increased based on the drive information,
After rising to S, drive frequency is 2000P after a predetermined time
Raise it to PS and drive normally.

The slow-up operation described above is shown in FIG.
In the block diagram of MPU14,
This is performed by reading the portion of the slow-up table from 19 and transferring it to the mechanism control unit 16, and the mechanism control unit 16 driving the stepping motor based on the read data.

Next, the slowdown operation according to this embodiment will be described.

FIG. 9 shows a slowdown table stored in the ROM. For the sake of explanation, a system using 500, 750, 1000, 2000, 2500 PPS as the frequency for performing the steady drive is assumed for the sake of description, like the slow-up table described above. This slowdown table uses all the drive frequencies other than the steady drive maximum frequency (here, 2500 PPS) and the frequency for stopping the steady drive minimum frequency (here, 500 PPS), and as shown in FIG. ， 100
It is one table in which excitation pulses are linked in the order of 0, 750, 500, 375PPS. The driving time at each frequency is set to be a predetermined time at the time of design.

For example, when the steady drive is performed at 2000 PPS, the frequency less than 2000 PPS on the slowdown table, here, the range of 1000, 750, 500, 375 PPS is read, and the drive is gradually performed based on the drive information. After the frequency is lowered to 375PPS, the excitation pulse is stopped after a predetermined time, and the motor is stopped.

As in the slow-up operation, the slow-down operation described above is similar to the slow-up operation. In the block diagram of FIG. 1, the MPU 14 performing the starting process reads the slow-down table portion from the ROM 19 and transfers it to the mechanism controller 16. Mechanism control unit
16 is performed by driving the motor based on the read data.

By the way, FIG. 10 shows the angular velocity curve of the motor pulley when the stepping motor is driven at a predetermined chopping level current setting value, and FIG. 11 drives the stepping motor by halving the chopping level current setting value of FIG. It is an actual measurement figure which shows the angular velocity curve of a motor pulley at the time of doing.

The one in FIG. 10 is driven with the chopping level current set value twice as large as that in FIG. 11, but hunting due to excessive torque is larger than that in FIG.

FIG. 12 is a graph showing the relationship between the drive frequency of the motor and the output torque. According to FIG. 12, the torque is larger when the motor drive frequency is lower, but not limited to this motor, a stepper motor can obtain a higher output when the drive frequency is lower, and as the drive frequency becomes higher. The output tends to be low.

Therefore, when the driving current is set at a constant value when the driving is performed while changing the speed, the movement due to the torque over becomes large and the read image deteriorates.
Noise and vibration may increase.

In order to solve such a problem, the following processing is performed in this embodiment.

FIG. 13 is an explanatory diagram showing a control example of the drive current at the time of slowing up.

As shown in FIG. 13, the set current value is switched as the drive frequency becomes higher, so that the drive matching the system load is performed. Here, a current of 25% is passed until switching to 750PPS, a current of 50% is passed until switching to 2000PPS, and a current of 100% is passed thereafter.

It should be noted that the current value switching points and the like are set in advance at the time of design and written in the ROM 19 in FIG. 1 in the form of a table. When actually driving, MPU
14 reads this table from ROM 19 and the mechanism control unit
Instruct 16 to realize the function of current control.

[0049]

According to the present invention constructed as described above, the following effects can be obtained.

According to the first aspect of the invention, when the stepping motor is driven stepwise by using various frequencies and reading is performed, the slow-up is used to ensure proper start-up, and the slow-up table is provided. Since only one type is required, minimization of the software control routine and minimization of the table storage area can be expected.

According to the second aspect of the present invention, when the stepping motor is driven stepwise by using various frequencies and the motor is stopped, the slowdown is used to ensure the proper stop and the slowdown. Since only one type of table is required, minimization of the software control routine and minimization of the table storage area can be expected.

According to the third aspect of the present invention, it is possible to avoid step-out, noise and vibration due to excessive output torque of the motor with respect to the load at the initial stage of starting the stepping motor.

According to the constitutions of claims 4 and 5, it is possible to easily set the slow-up / slow-down table.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the inside showing the outline of the reading unit (book scanner type) of the facsimile apparatus of this embodiment.

FIG. 3 is a side view of FIG.

FIG. 4 is an actual measurement diagram showing an example of a conventional general slow-up condition.

5 is an actual measurement diagram showing a speed curve of a reading sensor when the drive shown in FIG. 4 is performed.

FIG. 6 is an actual measurement diagram of a speed curve of a transmission pulley in the case where several slow-ups are first performed.

7 is an actual measurement diagram showing a speed curve of a reading sensor when the drive shown in FIG. 6 is performed.

FIG. 8 is an explanatory diagram showing a slow-up table stored in a ROM.

FIG. 9 is an explanatory diagram showing a slowdown table stored in a ROM.

FIG. 10 is an actual measurement diagram showing an angular velocity curve of a motor pulley when a stepping motor is driven at a predetermined chopping level current setting value.

FIG. 11: Set the chopping level current setting value of FIG. 10 to 1 /
It is an actual measurement figure which shows the angular velocity curve of a motor pulley at the time of driving a stepping motor by doubling.

FIG. 12 is a graph showing the relationship between the drive frequency of the motor and the output torque.

FIG. 13 is an explanatory diagram showing an example of control of a drive current at the time of slow-up.

[Explanation of symbols]

1 ... Reading unit, 2 ... Recording unit, 3 ... Reading scanning unit, 4 ...
Read processing unit, 5 ... Line memory, 6 ... Line memory control unit, 7 ... Recording scanning unit, 8 ... Recording processing unit, 9 ... Information compression / decompression unit, 10 ... RAM, 11 ... Communication control unit,
12 ... Modem, 13 ... Network control unit, 14 ... MPU, 15 ... Panel unit, 16 ... Mechanism control unit, 17 ... Power supply unit, 18 ... DM
A controller, 19 ... ROM, 20 ... stepping motor, 21 ... timing belt, 22 ... transmission pulley,
23 ... Drive wire, 24 ... Opposing pulley, 25 ... Read sensor, 26 ... Guide rail, 27 ... Scanner base.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04N 1/107

Claims (5)

[Claims] 1. A reading unit for reading an image while moving with respect to a fixed document, a stepping motor serving as a driving source of the reading unit, and a plurality of stepping motors for performing various speed changes to drive them stepwise. And an image reading device including a storage unit that stores the motor drive frequency of
A motor having a frequency equal to or lower than a target frequency on the slow-up table when the stepping motor is activated is provided with a slow-up table in which a plurality of the motor drive frequencies are arranged as elements in order to perform a slow-up at startup. An image reading apparatus comprising a control means that uses a drive frequency and switches from slow-up control to control for applying a steady drive pulse when the target frequency is reached. 2. A reading unit for reading an image while moving with respect to a fixed document, a stepping motor serving as a drive source of the reading unit, and a plurality of stepping motors for performing various speed changes and driving them stepwise. And an image reading device including a storage unit that stores the motor drive frequency of
A slowdown table formed by arranging a plurality of motor drive frequencies as elements for slowing down when stopped is provided in the storage means, and when stopping the stepping motor, a frequency equal to or lower than a target frequency on the slowdown table. The image reading apparatus is provided with a control means for starting the slowdown operation using the motor drive frequency corresponding to the above and stopping the drive of the stepping motor when the end of the slowdown table is reached. 3. A reading unit for reading an image while moving with respect to a fixed document, a stepping motor serving as a drive source of the reading unit, and a plurality of stepping motors for performing various speed changes to drive them stepwise. And an image reading device including a storage unit that stores the motor drive frequency of
A stepping motor is used as a driving source of the reading unit,
For the motor drive system used for control that accelerates more slowly than the slow-up operation required to start this stepping motor, control is performed to drive at a lower current value in the initial slow-up than when performing steady drive operation. An image reading apparatus comprising a control means. 4. The image reading apparatus according to claim 1, wherein a table in which the motor drive frequencies used during gear shifting are arranged in order from low to high is a slow-up table. 5. The image reading apparatus according to claim 2, wherein a table in which the motor drive frequencies used during gear shifting are arranged in order from high to low is a slowdown table.