JP2009049860A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of starting execution of image reading operation within a short time even when causing an image processing device in a power saving mode to perform the image reading operation. <P>SOLUTION: An image reading apparatus 1 includes: a motor 15 which gives a driving force for reciprocating a carriage 6 with an image sensor 11 mounted thereon; load measuring means 28 for measuring a driving load in driving the motor 15; motor drive control means 29 which controls and drives the motor 15 with reflection of the driving load measured by the load measuring means 29; and power saving mode setting means 30 for setting from a standby mode to a power saving mode, wherein the load measuring means 28 measures the driving load when the image reading apparatus 1 is shifted from the standby mode to the power saving mode by the power saving mode setting means 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus.

  A so-called image reading apparatus having an image reading function such as a copying apparatus or a scanner apparatus for reading an image on a document surface scans the document surface with an image sensor and reads the image with the image sensor. The image sensor is attached to the carriage, and is configured such that the image sensor can scan the document surface by moving the carriage by a carriage moving mechanism having a motor as a drive source.

  Incidentally, the driving load of the carriage moving mechanism may change due to environmental factors such as temperature and wear of components of the carriage moving mechanism. On the other hand, in order to read an image with a predetermined resolution, the image reading apparatus needs to set the scanning speed of the image sensor to a predetermined speed corresponding to the predetermined resolution. However, since the driving load of the carriage moving mechanism varies depending on environmental factors and the like, it is necessary to drive the carriage moving mechanism with a driving force in consideration of the driving load in order to scan at a predetermined speed. Therefore, in the image reading apparatus, for example, as disclosed in Patent Document 1, the driving load of the carriage driving mechanism is measured, and the carriage is moved by driving the motor with the driving force in consideration of the measured driving load. Thus, the image sensor can be moved at a predetermined speed regardless of the driving load.

  By the way, the image reading apparatus needs to hold data in order to suppress power consumption when the user's operation is not performed for a predetermined time and a standby mode in which an operation corresponding to the operation content can be started immediately according to the user's operation. Some have a so-called power saving mode in which power supply is continued only to the minimum necessary electric elements such as a memory and the power supply to the display panel and other electric circuits or electric elements is cut off. In an image reading apparatus having such a power saving mode, the drive load of the carriage moving mechanism is measured when shifting from the power saving mode to the standby mode. Some are configured to migrate.

JP 2003-23783 A

  However, since it takes several seconds to measure the driving load, if the driving load is measured when shifting from the power saving mode to the standby mode, the image processing apparatus in the power saving mode reads an image. When trying to perform the operation, there is a problem that it is necessary to wait for the measurement of the driving load to end. Accordingly, the present invention provides an image reading apparatus capable of starting an image reading operation in a short time even when an image processing apparatus in a power saving mode is to perform an image reading operation. The purpose is to provide.

  In order to solve the above-described problems, an image reading apparatus includes a motor that provides a driving force for reciprocating a carriage on which an image sensor is mounted, a load measuring unit that measures a driving load when driving the motor, and a load measurement. Load measuring means in an image reading apparatus, comprising: motor drive control means for controlling and driving the motor by reflecting the drive load measured by the means; and power saving mode setting means for setting the standby mode to the power saving mode. The power saving mode setting means measures the driving load when the image reading apparatus shifts from the standby mode to the power saving mode.

  By configuring the image reading apparatus in this way, there is a request for the image reading operation because the load measurement is performed at the time of setting the power saving mode before the image reading operation is requested from the user to the image reading apparatus. Sometimes, it is possible to shorten the time until the image reading operation is started.

  According to another invention, in addition to the above-described invention, the load measuring means reciprocates a carriage positioned at an initial position, and performs load measurement during the reciprocating movement.

  By configuring the image reading apparatus in this way, the load measurement is performed by reciprocating the carriage, so that the carriage returns to the initial position after the load measurement is completed. Therefore, it is possible to shorten the time until the image reading operation is started when the image reading operation is requested.

  In another invention, in addition to the above-described invention, the load measurement during the reciprocating movement is performed by measuring the driving load at the different moving speeds by changing the moving speed of the carriage in the forward path and the returning path.

  By configuring the image reading apparatus in this way, it is possible to measure the driving load for different moving speeds of the carriage.

  According to another invention, in addition to the above-described invention, the image reading apparatus performs alignment with the initial position of the carriage after receiving an instruction for an image reading operation.

  By configuring the image reading apparatus in this way, the position of the carriage is adjusted to the initial position after the instruction of the image reading operation is performed. The image reading operation can be started with high alignment accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Appearance structure of the scanner combined device)
FIG. 1 is a perspective view showing an external appearance of a scanner complex apparatus 1 as an image reading apparatus according to an embodiment of the present invention. The scanner multifunction device 1 includes a scanner configuration unit 2 and a printer configuration unit 3, and is configured as a so-called multifunction device including a copy function and a printer function in addition to a scanner function. In other words, the scanner composite apparatus 1 is connected to a personal computer (hereinafter simply referred to as a personal computer) PC, so that the image data read by the scanner configuration unit 2 is output to the personal computer PC, or the scanner composite device is connected to the personal computer PC. By sending image (printing) data to the apparatus 1, printing (printing) is performed in the printer configuration unit 3 based on the image (printing) data. Further, the image data read by the scanner construction unit 2 is sent to the printer construction unit 3 directly or via a personal computer PC to perform printing, thereby functioning as a copier.

  The scanner component 2 includes a document platen 4 made of a transparent plate such as a glass plate and a document cover 5 that covers the document placed on the document platen 4, a carriage 6, and the like. Various internal mechanisms to be described later are provided. The printer configuration unit 3 has a printing unit (not shown) inside, and prints (prints) the printing paper supplied from the paper feed mechanism 7 provided behind the scanner configuration unit 2 by the printing unit. The printing paper is discharged from a discharge unit 8 provided in front of the scanner component 2. The scanner multifunction device 1 is provided with operation buttons 9, and the operation buttons 9 are used to select various functions of the scanner multifunction device 1 and to perform operation instructions for the scanner multifunction device 1.

(Internal configuration of the scanner device)
FIG. 2 is a diagram showing a schematic structure of the scanner configuration unit 2 in the scanner complex apparatus 1 of the present embodiment. As shown in FIG. 2, the scanner complex device 1 includes a control circuit 10, a carriage 6 to which the image sensor 11 and the LED array 12 are attached, a carriage moving mechanism 13 for moving the carriage 6, and a movement amount of the carriage 6. The encoder 14 etc. for measuring are provided. The control circuit 10 also serves as a control unit for a printer function and a copy function in addition to the control of the scanner configuration unit 2.

  The carriage moving mechanism 13 includes a stepping motor (hereinafter referred to as “ST motor”) 15 that is a drive source, a worm gear 16 joined to the ST motor 15, a spur gear 17 that meshes with the worm gear 16 and rotates at a predetermined reduction ratio, A pulley 18A joined to the spur gear 17, a pulley 18B disposed with the document table 4 interposed between the pulley 18A, a timing belt 19 stretched between the pulley 18A and the pulley 18B, and a timing belt 19 The guide shaft 20 is disposed along the extending direction. In the following description, the direction from the pulley 18A toward the pulley 18B is defined as the front (front side), and the opposite direction is defined as the rear (rear side). The ST motor 15 is not limited to a stepping motor, and may be a DC motor.

  The timing belt 19 is rotated by receiving the driving force of the ST motor 15 via the worm gear 16, the spur gear 17, and the pulley 18A. A part of the timing belt 19 is fixed to the carriage 6. The carriage 6 is slidably connected to the guide shaft 20. Therefore, the carriage 6 moves along the guide shaft 20 by driving the ST motor 15 and rotating the timing belt 19.

  The encoder 14 is a so-called rotary encoder that is joined to the output shaft of the ST motor 15 and has a disk-like encoder board 21 and an encoder sensor 22 that rotate integrally with the rotation of the ST motor 15. Based on the pulse, the rotation direction and rotation amount of the ST motor 15 can be detected. Then, based on the rotation direction and rotation amount of the ST motor 15, the movement direction and movement amount of the carriage 6 can be known.

  As described above, the image sensor 11 and the LED array 12 are attached to the carriage 6. Illumination light is emitted from the LED array 12 to the document surface of the document placed on the document table 4, and the illumination light reflected by the document surface is received by the image sensor 11. In the image sensor 11, charges corresponding to the image on the original surface are accumulated, and an electric signal corresponding to the amount of charges is output from the image sensor 11.

(Electrical configuration of the scanner device)
FIG. 3 is a circuit block diagram showing an electrical configuration of the scanner complex apparatus 1 of the present embodiment. As shown in FIG. 3, the control circuit 10 is supplied with a CPU (Central Processing Unit) 23, a memory 24, and an external interface unit 25 having a USB interface for connecting the scanner multifunction device 1 to a personal computer PC. A rectifier circuit 26 that converts an alternating current into a direct current, an ASIC 27, and the like are provided.

  The CPU 23 configures a load measuring unit 28 as a load measuring unit having functions to be described later, a motor drive control unit 29 as a motor drive control unit, and a power saving mode setting unit 30 as a power saving mode setting unit. These means are functionally realized by the CPU 23 reading a control program stored in the memory 24. In addition to the CPU 23 and the memory 24, the motor control unit 31 cooperates with the motor drive control unit 29. In addition, in order to implement | achieve each of these means, you may employ | adopt the structure which comprises a dedicated circuit.

  The ASIC 27 includes an image sensor control unit 32, an LED array control unit 33, an encoder control unit 34, a motor control unit 31 and the like. The image sensor control unit 32 has a function of outputting a signal for instructing the image sensor 11 to read a document or inputting a read result signal from the image sensor 11 to convert it into a gradation value (image data). . The LED array control unit 33 outputs a signal that causes the LED array 12 to irradiate illumination light that illuminates the document surface. The encoder control unit 34 receives an encoder pulse output from the encoder 14 and detects the rotation amount, rotation speed, and rotation direction of the ST motor 15. The motor control unit 31 controls the rotational speed of the ST motor 15 by supplying the direct current output from the rectifier circuit 26 to the ST motor 15 and controlling the drive current applied to the ST motor 15. The motor controller 31 receives the encoder pulse and the image sensor drive pulse from the encoder controller 34 and the image sensor controller 32, respectively. Note that the control circuit 10 may be configured to use a personal computer PC.

(Scanner operation)
Next, the operation of the scanner complex apparatus 1 having the above-described configuration will be described. First, an initial operation executed when a power switch (not shown) provided in the operation button 9 is turned on will be described. In this initial operation, alignment of the carriage 6 to the initial position 35 and measurement of the driving load of the carriage moving mechanism 13 are performed.

When a power switch (not shown) provided in the operation button 9 is turned on, the motor drive control unit 29 performs alignment processing of the carriage 6 to the initial position 35. Next, the load measuring unit 28 measures the driving load of the carriage moving mechanism 13. After this initial operation is performed, when an image reading start button (not shown) provided on the operation button 9 is turned on, the carriage 6 is moved forward by the carriage moving mechanism 13 and the image sensor 11 is moved. An image reading operation for reading an image by scanning the document surface is performed.

  The alignment process of the carriage 6 to the initial position 35 is performed as follows. A stopper 36 that functions as a position reference in the scanner complex device 1 is provided at the rear end of the movement range of the carriage 6. When aligning the carriage 6 to the initial position 35, first, the carriage 6 is moved backward, and the carriage 6 is brought into contact with the stopper 36. Thereby, the carriage 6 is positioned with respect to the stopper 36 which is the position reference of the scanner complex apparatus 1. Thereafter, the carriage 6 is moved forward by a predetermined distance to the initial position, thereby positioning the carriage 6 at the initial position. Thus, after positioning the carriage 6 with respect to the position reference (stopper 36), the position moved a predetermined distance from this position is set as the initial position 35, so that the initial position 35 is set with respect to the position reference (stopper 36). The determined accuracy can be high.

  Further, the measurement of the driving load of the carriage moving mechanism 13 by the load measuring unit 28 is performed as follows. In the scanner complex apparatus 1 according to the present embodiment, the driving load is measured when the carriage 6 is moved at the moving speed when reading and scanning the document surface. The scanning speed of the carriage 6 in the scanner complex apparatus 1 is low when the high resolution reading can be performed (hereinafter, this speed is simply referred to as low speed), and the image reading speed is high at a low resolution. Two types of speeds are set, which are high speeds that can be performed (hereinafter, this speed is simply referred to as high speed). The moving speed of the carriage 6 at low speed is the speed when the ST motor 15 is driven at, for example, 5000 Hz, and the moving speed of the carriage 6 at high speed is the speed when the ST motor 15 is driven at, for example, 15840 Hz. Therefore, when measuring the driving load, the carriage 6 is moved forward at a predetermined distance at a low speed, and subsequently moved at a high speed for a predetermined distance. Then, while moving at each speed, the driving load of the carriage moving mechanism 13 is measured for each speed. The carriage 6 moved forward for measuring the driving load is moved backward at a low speed and returned to the initial position 35.

  The driving load can be measured based on the current value applied to the ST motor 15 as follows, for example. The value of the current applied to the ST motor 15 necessary to generate a driving force for moving the carriage 6 at a predetermined speed in the ST motor 15 is proportional to the driving load. Therefore, the relationship between the driving load of the carriage moving mechanism 13 and the current value applied to the ST motor 15 is checked in advance for each moving speed at the time of reading and scanning of the carriage 6, and this relationship is stored in the memory 24 in the form of a data table or the like. Remember. Then, the current value applied to the ST motor 15 when moving the carriage 6 at a predetermined speed is measured, and the driving load is obtained from the data table based on this current value.

  The driving load measured in this way is stored in a register (not shown) of the motor control unit 31. The motor drive control unit 29 controls the drive of the ST motor 15 based on the drive load stored in a register (not shown) when the carriage 6 moves to perform scanning for image reading.

  After the measurement of the driving load in the initial operation described above, the carriage 6 returns to the initial position 35 and waits at the initial position 35 until an instruction for an image reading operation is given. When an instruction for an image reading operation (for example, an on operation of an image reading start button (not shown) provided in the operation button 9) is given to the scanner multifunction device 1, the scanner multifunction device 1 performs an image reading operation. I do. In other words, the CPU 23 starts driving the image sensor 11, the LED array 12, and the ST motor 15 in response to an instruction for an image reading operation. Then, while reading the document surface illuminated by the LED array 12 with the image sensor 11, the carriage 6 is moved forward from the initial position by the ST motor 15, whereby the image sensor 11 reads the image on the document surface. Scan. The image sensor 11 outputs an electrical signal corresponding to the image on the document surface. This electric signal is sent to the personal computer PC as image data of an image on the original surface. When the image data is copied, the printer construction unit 3 performs printing based on the image data. In addition, this image data may be recorded on a recording means of a personal computer PC for image processing.

  The carriage 6 moves forward by a distance corresponding to the size of the document, scans the entire document surface, and then turns backward to stop at the initial position 35. Then, it waits at the initial position 35 until an instruction for the next image reading operation is given. Note that the amount of forward movement of the carriage 6 in the image reading operation is set by a document size selection button (not shown) provided on the operation button 9. That is, the motor drive control unit 29 obtains the movement distance of the carriage 6 from the rotation amount of the ST motor 15 detected by the encoder 14 and until this movement distance reaches a distance according to the size of the selected document P. The ST motor 15 is driven and controlled to move the carriage 6 forward. When performing the image reading operation, the reading resolution is also designated, and the motor drive control unit 29 drives the ST motor 15 so that the carriage 6 is moved at the scanning speed corresponding to the designated resolution. .

  By the way, the power saving mode setting unit 30 measures a time during which an instruction operation such as an image reading operation is not performed on the scanner multifunction device 1 by a timer (not shown), and when this time reaches a predetermined time. In order to reduce power consumption, the scanner multifunction device 1 is set to the power saving mode. In this power saving mode, power supply is continued only to the minimum necessary electrical elements such as memory that needs data retention, and power supply to the display panel and other electrical circuits or electrical elements is cut off, so that power consumption can be reduced. It has become. When an instruction operation such as an image reading operation is performed on the scanner multifunction device 1 after entering the power saving mode, the power saving mode setting unit 30 supplies power to the display panel, other electric circuits, or electric elements. The process is resumed and the scanner multifunction device 1 is set to the standby mode.

  The state of shifting to the power saving mode is a case where the scanner multifunction device 1 is not operating for a predetermined time as described above, and it can be said that there is a low possibility that the user will operate the scanner multifunction device 1 thereafter. Therefore, in the scanner multifunction device 1, when the power saving mode setting unit 30 shifts to the power saving mode, the load measuring unit 28 measures the driving load of the carriage moving mechanism 13, and the measured driving load is stored in the memory 24. In this state, the scanner multifunction device 1 is shifted to the power saving mode. After that, when the standby mode is set, the motor drive control unit 29 performs the movement control of the carriage 6 based on the drive load measured at the time of shifting to the power saving mode and stored in the memory 24. As described above, by measuring the driving load at the time of shifting to the power saving mode, the driving load is changed from the value measured in the initial operation described above due to the subsequent operation of the scanner complex apparatus 1 or the change in temperature or the like. In this case, the value of the driving load can be set to a value that is new in time. In addition, as explained in the above-mentioned section of the prior art, driving is performed when shifting from the power saving mode to the standby mode, compared to performing measurement of the driving load when shifting from the power saving mode to the standby mode. Since the load measurement can be omitted, it is possible to quickly shift from the power saving mode to the standby mode. That is, when the image processing apparatus in the power saving mode is to perform an image reading operation, the image reading operation can be started in a short time.

  In the measurement of the driving load performed when shifting to the power saving mode, the carriage 6 is reciprocated forward at low speed and high speed, and the driving load at each speed is measured. That is, first, the carriage 6 is moved a predetermined distance from the initial position 35 toward the front, and the driving load when moving at this speed (low speed) is measured. Then, the moving direction is changed, the carriage 6 is moved rearward at high speed, and the driving load when moving at this speed (high speed) is measured. As described above, the carriage 6 is reciprocated while changing the speed between the forward path and the backward path, and the driving load of the carriage moving mechanism 13 at each speed is measured, whereby the driving load at different speeds can be measured.

  Here, the moving speed of the carriage 6 in the forward path and the backward path is set to a low speed and a high speed, which are speeds when the carriage 6 scans the document surface. Therefore, it is possible to measure the driving load corresponding to the moving speed of the carriage 6 during image reading and scanning. The moving speed of the carriage 6 in the forward path and the return path when measuring the driving load may be a speed other than the speed when the carriage 6 scans the document surface. Then, the speed at which the drive load is measured may be different between the forward path and the return path, and the drive load for an arbitrary moving speed may be estimated from the drive loads for different speeds.

  It is to be noted that the moving distance of the forward path and the backward path when the carriage 6 is reciprocated is the same, and the carriage 6 is positioned at the initial position 35 in a state where the carriage 6 is reciprocated to measure the driving load. In addition, when the driving load is measured for each speed, the measured value of the driving load is stored in the memory 24 as described above, and the power saving mode setting unit 30 operates in the state where the measurement result is stored in the memory 24. The composite apparatus 1 is shifted to the power saving mode.

  When shifting from the power saving mode to the standby mode, processing for aligning the carriage 6 to the initial position 35 is performed in the same manner as when the power switch (not shown) is turned on. The carriage 6 is reciprocated for the measurement of the driving load performed when shifting to the power saving mode. As described above, since the traveling distance of the forward path and the backward path is the same, the carriage 6 should be aligned with the initial position 35. However, while the scanner 6 is in the power saving mode, an impact is applied to the scanner multifunction device 1. In some cases, the carriage 6 is displaced from the initial position 35. Therefore, when shifting from the power saving mode to the standby mode, the carriage 6 is once brought into contact with the stopper 36 and positioned with respect to the stopper 36 as described above. Thereafter, the carriage 6 is positioned at the initial position by moving forward a predetermined distance to the initial position.

  As described above, in the drive load measurement performed at the time of shifting to the power saving mode, the carriage 6 is reciprocated forward from the initial position 35 and returned to the initial position 35. Therefore, when shifting from the power saving mode to the standby mode, the distance that the carriage 6 moves until it abuts against the stopper 36 can be shortened, and the alignment process of the carriage 6 to the initial position 35 can be performed in a short time. .

1 is a perspective view showing an appearance of a scanner device according to an embodiment of the present invention. It is a figure which shows the outline of the internal mechanism of the scanner apparatus shown in FIG. FIG. 2 is a circuit block diagram showing an electrical configuration of the scanner device shown in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Scanner apparatus (image reading apparatus) 6 ... Carriage 11 ... Image sensor 15 ... ST motor (motor) 28 ... Load measuring means 29 ... Motor drive control means 30 ... Power saving mode setting means 35 ・ ・ ・ Initial position

Claims (4)

A motor that provides a driving force for reciprocating the carriage on which the image sensor is mounted;
Load measuring means for measuring a driving load when driving the motor;
Motor drive control means for controlling and driving the motor by reflecting the drive load measured by the load measurement means;
A power saving mode setting means for setting the standby mode to the power saving mode;
In an image reading apparatus comprising:
The image reading apparatus, wherein the load measuring means measures the driving load when the image reading apparatus shifts from the standby mode to the power saving mode by the power saving mode setting means.   The image reading apparatus according to claim 1, wherein the load measuring unit reciprocates the carriage positioned at an initial position, and performs load measurement during the reciprocal movement.   3. The image reading apparatus according to claim 1, wherein the load measurement during the reciprocating movement is performed by measuring the driving load at the different moving speeds by changing the moving speed of the carriage in the forward path and the backward path. .   The image reading apparatus according to claim 1, wherein the image reading apparatus aligns the carriage to an initial position after receiving an instruction for an image reading operation.

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