Image reading device and program

Abstract

To provide an image reading device that relatively simply achieves both a further improvement in the quality of image data and further acceleration of acquisition of the image data, and a program for causing a computer to function as respective means of an image reading device.SOLUTION: An image reading device 300 comprises: an image reading unit 310 that performs image reading; a reading system driving unit 313 for moving a target in the image reading; and signal generation means that generates signals for driving the image reading unit 310, and the image reading device performs the image reading with the image reading unit 310 based on the signals generated by the signal generation means while moving the target with the reading system driving unit 313, and thereby acquires image data. The reading system driving unit 313 moves the target so that the target changes at a speed according to a predetermined drive speed profile. The signal generation means generates the signals at a timing when the travel distance of the target becomes an equal interval based on the drive speed profile.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates primarily to an image reading device. [Background technology]

[0002] Among image reading devices such as scanners, there are some that perform image reading not only while the rotation speed of the scanner motor that moves the scanner unit is constant, but also while the rotation speed is changing, that is, while the scanner motor is accelerating or decelerating (see Patent Document 1). Such image reading can be advantageous in both improving the quality of image data and increasing the speed of acquiring the image data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-284284 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration of Patent Document 1, if the change in the rotation speed of the scanner motor is nonlinear, there is a possibility that the accuracy of image reading during the change may decrease.

[0005] The present invention was made in response to the inventor's recognition of the above-mentioned problems, and has an exemplary object to relatively easily achieve both higher quality image data and faster acquisition of the image data. [Means for solving the problem]

[0006] One aspect of the present invention relates to an image reading device, the image reading device comprising: An image reading device comprising: an image reading means for reading an image; a driving means for moving an object when reading the image; and a signal generating means for generating a signal for driving the image reading means, wherein the image reading means reads the image based on a signal generated by the signal generating means while the object is moved by the driving means, thereby acquiring image data, The driving means moves the object so that the object changes at a speed that follows a predetermined driving speed profile; The signal generating means generates signals at timings at which the moving distance of the object becomes equal intervals based on the drive speed profile. It is characterized by: Effect of the Invention

[0007] According to the present invention, it is possible to improve the quality of image data and to increase the speed of acquiring the image data. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a multifunction peripheral according to an embodiment. [Diagram 2] FIG. 1 is a block diagram showing an example of the system configuration of a multifunction peripheral according to an embodiment. [Diagram 3] FIG. 4 is a block diagram showing a configuration example of a drive unit. [Figure 4] FIG. 1 is a block diagram showing an example of the configuration of a detection system capable of reading an image. [Diagram 5] 4 is a timing chart showing an example of a waveform of a control signal of a motor control unit. [Figure 6] 4 is a timing chart showing an example of a waveform of an encoder signal of an encoder. [Figure 7] FIG. 4 is a diagram showing the logic when measuring the amount of rotation of a motor. [Figure 8] 4 is a timing chart showing the waveforms of signals during image reading. [Figure 9] 4 is a timing chart for explaining a manner in which the rotation speed of a motor changes. [Figure 10] 4 is a timing chart showing the amount of rotation of a motor. [Figure 11] 4 is a graph showing the position of a moving object versus time when the motor is in an accelerating state. [Figure 12] 4 is a graph showing the position of a moving object versus time when the motor is in a deceleration state. [Figure 13] FIG. 1 is a diagram showing the relationship between the encoder position and the reading position. [Figure 14] FIG. 13 is a diagram showing accumulation time in a CIS. [Figure 15] 4 is a timing chart showing a state of a signal SH during acceleration. [Figure 16] 4 is a timing chart showing a state of a signal SH during deceleration. [Figure 17] 6 is a timing chart of image reading when accelerated reading is not required. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] 1 is a perspective view of a multi-function peripheral (MFP) 300 according to an embodiment. The multi-function peripheral 300 includes an image reading unit 310 and a print head 316 (see FIG. 2) that records an image on a recording medium. 2 is a block diagram showing an example of the system configuration of a multifunction device 300. The multifunction device 300 has various functions such as a scanner function for reading an image from a document and a print function for recording on a recording medium such as paper. In this embodiment, the multifunction device 300 has a control board 301, an image reading unit 310, a print unit 315, an operation panel 320, and a power supply unit 340.

[0011] The scanner function includes a function of reading on a document loading platform and a function of reading using an ADF (Automatic Document Feeder), the details of which will be described later.

[0012] The control board 301 includes a control IC (integrated circuit) 302, a system bus 303, a ROM 304, and a RAM 305. The control IC 302 includes an MPU (microprocessor unit) 306, a read image processing unit 307, a recorded image processing unit 308, and an image encoding unit 309, and performs drive control of the entire system while communicating with other elements via the system bus 303. The ROM 304 stores information required to realize the functions of the multifunction device 300, such as program codes used in the calculation processing of the MPU 306, initial value data, table data, etc. The RAM 305 functions as a work memory and can be used as, for example, a calculation buffer, an image memory, etc.

[0013] The image reading unit 310 includes CIS (contact image sensor) 30 and CIS 31, a read image correction unit 312, and a reading system drive unit 313. A known image sensor may be used for the CIS 30 and 31, and a CCD / CMOS image sensor in which a plurality of pixels are arranged may be used. The CIS 30 is capable of selectively reading the document on the document loading platform and reading the document front side by the ADF, and may be expressed as the front side CIS 30. The CIS 31 is capable of reading the document rear side by the ADF, and may be expressed as the back side CIS 31. When reading images from both sides of a document, both the CIS 30 and 31 are subject to drive control.

[0014] When reading from the document loading platform, the CIS 30 scans the document, and when reading from the ADF, the document is transported to the CIS 30 (and 31). In either case, the CIS 30 (and 31) moves relative to the document to read the image.

[0015] The reading system drive unit 313 includes an electric motor that generates power, and the positions of the CISs 30 and 31 are moved based on the power, and the CISs 30 and 31 sequentially read images from the document and convert them into image signals to generate image data. The read image correction unit 312 can perform correction processing such as shading correction on the image data obtained in this manner, and the read image processing unit 307 can perform predetermined image processing.

[0016] Incidentally, the concept of an image that can be read from a document includes tangible objects such as letters, symbols, figures, photographs, etc., as well as the spaces that may form between them; in the following explanation, these are collectively referred to as image information, and the acquisition of image information can be referred to as image reading or image acquisition.

[0017] The reading system drive unit 313 may include other power sources necessary for realizing image reading, in addition to the motors for moving the positions of the CISs 30 and 31. Examples of such power sources include a motor for transporting the document, and a motor for driving rollers that separate and pick up the documents when there are two or more documents. Furthermore, the reading system drive unit 313 may also include other elements necessary for realizing image reading, such as a driver that controls the driving of the CISs 30 and 31.

[0018] The main elements for realizing the functions of the image reading unit 310 are typically arranged in the upper part of the multifunction device 300, and below that a print unit 315 for recording on a recording medium can be arranged. In this embodiment, the print unit 315 includes a print head 316, a recording signal output unit 317, and a recording system drive unit 318, and performs recording by an inkjet recording method.

[0019] The print head 316 is provided with a plurality of nozzles, and ink can be ejected individually from each of the plurality of nozzles. A recording system drive unit 318 moves the print head 316 to a desired position, while a recording signal output unit 317 outputs a recording signal to the print head 316 based on image data obtained by image processing by the recording image processing unit 308. Based on this recording signal, the print head 316 executes recording on the recording medium by ejecting ink from the corresponding nozzles.

[0020] Operation panel 320 includes display unit 321, operation unit 322, and operation panel IF (interface) unit 323. Display unit 321 and operation unit 322 are connected to system bus 303 via operation panel IF unit 323, and such a configuration makes it possible, for example, to output an image to be displayed to display unit 321, to accept operation input to operation unit 322, and the like.

[0021] Additionally, the control board 301 further includes an audio output unit 325, a communication connection unit 327, an external IF (interface) unit 331, a non-volatile storage device 333, and a wireless LAN module 334. The audio output unit 325 can convert, for example, audio data into a signal and output a voice message via a speaker 326, which is an external sound source. The communication connection unit 327 is connected, for example, to a communication network 328 or a telephone 329, and can input and output audio data and encoded data. The encoded data can be converted to and from image data by an image encoding unit 309.

[0022] The external IF unit 331 is configured as an external connection means conforming to a predetermined standard such as the USB standard, and allows an external device 332 such as a personal computer to be connected to the multifunction device 300. A flash memory or the like is typically used for the non-volatile storage device 333, and work data, image data, and the like can be stored even when the multifunction device 300 is in an inactive state. The wireless LAN module 334 can input and output image data from an external access point. The power supply unit 340 supplies power necessary for each element of the multifunction device 300, such as the control board 301, the image reading unit 310, the print unit 315, and the operation panel 320, to realize their functions.

[0023] Some of the functions of such a multifunction device 300 are exemplified below.

[0024] - Scan operation First, image processing such as shading correction is performed by a read image correction unit 312 on the image information read by the CIS 30 and 31 of the image reading unit 310. The image information is expanded in the RAM 305 as image data by a read image processing unit 307, and then compressed and encoded, for example, in JPEG format by an image encoding unit 309. The encoded data is output to an external device 332 via an external IF unit 331. In the scan operation, the image data of the image information read by the CIS 30 and 31 can be acquired in this manner.

[0025] - Copy action First, image processing such as shading correction is performed by a read image correction unit 312 on the image information read by the CIS 30 and 31 of the image reading unit 310. The image information is expanded as image data in the RAM 305 by the read image processing unit 307, and then compressed and coded in, for example, JPEG format by the image coding unit 309 and temporarily stored in, for example, the RAM 305. The image data is sequentially sent to a recording image processing unit 308 and converted into print data. The print data is output to a print head 316 via a recording signal output unit 317, whereby recording is performed on a recording medium. In the copy operation, the image information read by the CIS 30 and 31 is thus recorded on a recording medium and can be duplicated.

[0026] - Fax sending operation First, image processing such as shading correction is performed by the read image correction unit 312 on the image information read by the CIS 30 and 31 of the image reading unit 310. The image information is expanded as image data in the RAM 305 by the read image processing unit 307, and then compressed and encoded in, for example, MR (modified read) format by the image encoding unit 309, and temporarily stored in, for example, the RAM 305. The communication connection unit 327 transmits and receives a signal to start facsimile communication, and then starts transmitting the image data. The transmission of the image data is continued until completion, while the image reading by the CIS 30 and 31, and the associated encoding and temporary storage of the image data are performed. In this way, in the facsimile transmission operation, the desired image data can be transmitted to the communication target by facsimile.

[0027] - Fax reception operation For example, in response to reception from the communication network 328, the communication connection unit 327 transmits and receives a signal to start facsimile communication, and then starts receiving image data. The image data is demodulated by the image encoding unit 309 and then expanded in the RAM 305. The image data is sequentially sent to the recording image processing unit 308 and converted into print data. The print data is output to the print head 316 via the recording signal output unit 317, whereby the data is recorded on the recording medium. In this way, in the facsimile receiving operation, any image data can be received from the communication target by facsimile.

[0028] - Print operation A print job sent from an external device 332 and received via an external IF unit 331 is processed by an MPU 306, and is written as image data in a RAM 305 by an image encoding unit 309 based on instruction commands, parameters, etc. included in the job. The image data is sent in sequence to a recording image processing unit 308 and converted into print data. The print data is output to a print head 316 via a recording signal output unit 317, whereby recording is performed on a recording medium. In the printing operation, any image information can be recorded on a recording medium in this manner, and generated as a printed matter.

[0029] 3 is a block diagram showing an example of the configuration of a drive unit DR for executing image reading and document transport. That is, the concept of the drive unit DR includes the reading system drive unit 313 and the recording system drive unit 318 described above.

[0030] The driving unit DR includes a driving control unit 400, motor drivers 410 and 440, motors 420 and 450, and encoders 430 and 460. The motor driver 410, the motor 420, and the encoder 430 are provided corresponding to the image reading function, and may be respectively indicated as an image reading unit motor driver 410, an image reading unit motor 420, and an image reading unit encoder 430. The motor driver 440, the motor 450, and the encoder 460 are provided corresponding to the document transport function, and may be respectively indicated as a document transport system motor driver 440, a document transport system motor 450, and a document transport system encoder 460.

[0031] The drive control unit 400 includes, as elements corresponding to the image reading function, a motor control unit 401, an encoder input unit 402, a servo control unit 406, and a position and speed detection unit 407. These may also be referred to as the image reading unit motor control unit 401, the image reading unit encoder input unit 402, the image reading unit servo control unit 406, and the image reading unit position and speed detection unit 407, respectively.

[0032] Moreover, the drive control unit 400 further includes, as elements corresponding to the document transport function, a motor control unit 404, an encoder input unit 405, a servo control unit 408, and a position and speed detection unit 409. These may also be indicated as document transport system motor control unit 404, document transport system encoder input unit 405, document transport system servo control unit 408, and document transport system position and speed detection unit 409, respectively.

[0033] With this configuration, the drive control unit 400 generates a PWM (pulse width modulation) signal to control the rotation speed of each motor. For example, in image reading, the motor driver 410 generates power (rotation) by providing a current based on the PWM signal to the motor 420. A DC motor is typically used for the motor 420, and the power is transmitted to a downstream element via a power transmission mechanism such as gears and a belt. The encoder 430 is a rotary encoder arranged coaxially with the motor 420, and detects the direction and amount of rotation of the motor 420.

[0034] As in the above-mentioned image reading, the motor driver 440, the motor 450 and the encoder 460 each realize a corresponding function in transporting the document.

[0035] In image reading (as well as in document transport), servo control is performed when controlling the drive of motor 420. That is, encoder input unit 402 generates a signal based on an encoder signal, which is a detection signal from encoder 430, and position and speed detection unit 407 thereby detects the rotation direction, rotation amount, and rotation speed of motor 420. The rotation amount of motor 420 corresponds to the position of the moving object (here, CIS 30 or 31).

[0036] The servo control unit 406 compares the result of the detection by the position and speed detection unit 407 with a target value, and generates a correction signal based on the result of the comparison so that the motor 420 is controlled in a desired manner (typically, feedback control is performed using PID control). The motor control unit 401 generates a PWM signal based on the signal from the servo control unit 406.

[0037] 4 is a block diagram showing an example of the configuration of a detection system SY capable of reading an image. The detection system SY includes an image reading sensor 510 as the CIS 30 or 31, a CIS control unit 500 that controls the driving of the image reading sensor 510, and an AFE (analog front end) 520. The CIS control unit 500 includes an accumulation start signal generation unit 501, a CIS / AFE drive signal generation unit 502, and an image data input unit 503.

[0038] An accumulation start signal generating unit 501 generates an accumulation start signal (hereinafter, "signal SH"; details will be described later) for starting charge accumulation in the sensor 510. The sensor 510 accumulates charges generated by photoelectric conversion based on this signal SH, and obtains a group of pixel signals based on the amount of accumulated charge as an image signal. The image signal, which is an analog signal obtained by image reading by the sensor 510, is converted into a digital signal by AD (analog-to-digital) conversion by the AFE 520. An image data input unit 503 performs a predetermined correction process on the digital signal to generate image data, and a drive signal generating unit 502 generates drive signals for driving and controlling the sensor 510 and the AFE 520.

[0039] Fig. 5 is a timing chart for explaining an example of the waveform of a control signal of a motor control unit (here, motor control unit 401, but the same applies to motor control unit 404). Fig. 6 is a timing chart for explaining an example of the waveform of an encoder signal of an encoder (here, encoder 430, but the same applies to encoder 460).

[0040] 5, the signals supplied from the motor control unit 401 to the motor driver 410 are the signal ENABLE and the signal PHASE. The signal ENABLE is a signal for exciting the motor 420, and is set to excite the motor 420 when at an H (high) level and to suppress the excitation when at an L (low) level.

[0041] The signal PHASE is a PWM signal for setting the rotation direction and current value of the motor 420. Its period PERIOD is generally fixed and can be set to, for example, 25 kHz (kilohertz). Duty (or duty ratio) indicates the ratio of the period of the H level of the signal PHASE to the period PERIOD. For example, Duty=50% indicates that the motor 420 is stopped. Duty>50% indicates that the motor 420 is rotated in the forward direction (the scanning direction of the document (from the home side to the away side)), and the closer the duty is to 100%, the faster the rotation speed becomes. Moreover, Duty<50% indicates that the motor 420 is rotated in the reverse direction (the return direction of the document (from the away side to the home side)), and the closer the duty is to 0%, the faster the rotation speed becomes.

[0042] 6, the encoder 430 outputs two-phase signals, signals ENC_A and ENC_B. To allow the rotation direction to be known, when the phase of the signal ENC_A leads the phase of the signal ENC_B, the direction is forward (scan direction), and when the phase of the signal ENC_A lags the phase of the signal ENC_B, the direction is reverse (return direction).

[0043] That is, the encoder input unit 402 generates a signal based on the encoder signal, which is a detection signal from the encoder 430, and the position and speed detection unit 407 thereby detects the rotation direction, rotation amount (position of the moving object), and rotation speed of the motor 420. The encoder signal is passed through a noise filter in the encoder input unit 402 to remove, for example, signals with a relatively short pulse width, and then input to the position and speed detection unit 407 as signals ENC_A and ENC_B. The rotation amount is detected by measuring the edges (rising edges or falling edges) of the signals ENC_A and ENC_B, and the rotation speed is detected by measuring the time difference between those edges.

[0044] 7 shows the logic for measuring the amount of rotation based on the above-mentioned encoder signals. In this embodiment, at the rising edge and falling edge of one of the signals ENC_A and ENC_B, a measurement counter is incremented (+1) or decremented (-1) based on the signal value of the other of the signals ENC_A and ENC_B.

[0045] For example, if the signal ENC_B is at L level at the rising edge of the signal ENC_A, it is incremented (+1).The same applies to the cases where the signal ENC_B is at H level at the falling edge of the signal ENC_A, where the signal ENC_A is at H level at the rising edge of the signal ENC_B, and where the signal ENC_A is at L level at the falling edge of the signal ENC_B.

[0046] On the other hand, if the signal ENC_B is at H level at the rising edge of the signal ENC_A, it is decremented by -1. The same applies to the cases where the signal ENC_B is at L level at the falling edge of the signal ENC_A, where the signal ENC_A is at L level at the rising edge of the signal ENC_B, and where the signal ENC_A is at H level at the falling edge of the signal ENC_B.

[0047] The rotation speed can be detected by calculating the inverse of the time difference between the edges. For example, the falling edge of the signal ENC_B and the rising edge of the signal ENC_A correspond to one rotation of the slit of the encoder 430. Therefore, when these times are T0 and T1, respectively (see FIG. 6), the rotation speed can be expressed as 1 / (T1-T0) [Slit / sec].

[0048] 8 is a timing chart showing, as an example, the waveforms of the signals when the CIS 30 reads an image. In the figure, as signals for controlling the driving of the CIS 30, a signal SH for starting charge accumulation, a CLK signal for transferring a signal according to the amount of accumulated charge, and a pixel signal VOUT based on the amount of accumulated charge are shown. Also shown are a signal MCLK, which is a clock signal for driving the AFE 520, and a signal TSMP for sampling a signal according to the amount of accumulated charge.

[0049] Here, the CIS 30 is composed of a plurality of pixels arranged in a matrix, and the signal SH is given to each row so that it becomes an H level pulse, and image reading is started at the timing when the H level pulse of the signal SH corresponding to the first row is given. One signal CLK is given to each pixel of the corresponding row, and the signal sampled by the pixel up to that point is output as the signal VOUT. The signal MCLK can be other numbers depending on the configuration of the AFE 520, but here it is given so that the number of clocks per single pixel is 4. Also, the signal TSMP is given to a single pixel with an H level pulse, which determines the timing of the sampling. In the AFE 520, sampling is performed when the signal TSMP is at H level, and the sampled signal is fixed (held) when it becomes L level, that is, at the timing shown by the arrow.

[0050] In another embodiment, the CIS 30 may be configured to be able to switch the resolution, in which case a signal for switching the resolution may be added.

[0051] FIG. 9 is a timing chart for explaining the manner in which the rotation speed of motor 420 changes when reading an image, and FIG. 10 is a timing chart showing the amount of rotation of motor 420 (position of the moving object) at that time.

[0052] In general, the rotation speed of the motor 420 may undergo a period of acceleration or deceleration due to its inertia force while it is moving from a stopped state to a state of constant speed rotation, or while it is moving from a constant speed state to a stopped state. Therefore, in the example of Fig. 10, the motor 420 may include an acceleration state, a constant speed state, and a deceleration state. In the acceleration state, the motor 420 is controlled so that the rotation speed gradually increases to a target speed, in the constant speed state, the rotation speed is controlled to maintain the target speed, and in the deceleration state, the rotation speed is controlled so that the rotation speed gradually decreases to the target speed.

[0053] In the following description, the above-mentioned acceleration state, constant velocity state, and deceleration state may be simply expressed as acceleration, constant velocity, and deceleration, respectively.

[0054] The target speed is set in advance by the servo control unit 406 (servo control unit 408 in the case of the motor 450) described with reference to Fig. 3, and may be set as a constant value in a constant speed state, but may be set to follow a predetermined acceleration / deceleration characteristic in an accelerating and decelerating state. This acceleration / deceleration characteristic may be a function of time, or may be set by a table value. The acceleration / deceleration characteristic may be expressed as an acceleration / deceleration profile, or simply as a profile.

[0055] Here, the rotation amount of the motor 420 can be calculated by integrating the rotation speed. Therefore, the characteristics in the accelerating and decelerating states can be calculated by integrating the above-mentioned function or table value. Alternatively, the calculation result by the integration may be stored in advance in a predetermined memory.

[0056] FIG. 11 shows the time from T1 to T2 in a certain row when the motor 420 is in an accelerating state during image reading. N (Hereinafter, when no distinction is made, the time will be referred to as T1, etc.) and the positions Y1 to Y N (Hereinafter, when no distinction is made, the positions will be referred to as positions Y1, etc.) Similarly, Fig. 12 shows a graph when motor 420 is in a deceleration state.

[0057] In Fig. 11 (acceleration state), positions Y1, etc. are shown at equal intervals at a distance less than the acceleration distance, and times T1, etc. corresponding to these positions Y1, etc. are shown. Note that positions Y1, etc. may be set in advance to known values. Similarly, in Fig. 12 (deceleration state), positions Y1, etc. are shown at equal intervals at a distance less than the deceleration distance, and times T1, etc. corresponding to these positions Y1, etc. are shown. In each figure, the time and position at the start of acceleration / deceleration are set as origin 0, and times T1, etc. are included in the acceleration period in Fig. 11, or are included in the deceleration period in Fig. 12.

[0058] Details will be described later, but the positions Y1, etc. and the times T1, etc. are represented by preset acceleration or deceleration characteristics, and pixel signals are obtained by the signal SH at multiple positions Y1, etc. that are equally spaced on the original document, and image reading is performed.

[0059] The acceleration characteristic (Figure 11) is expressed by an n-th degree polynomial using a function of time. In this example, y=a n t n +a n―1 t n―1 +a n―2 t n-2 +···+a1t It can be expressed as (Equation 1). Here, a1 to a n is a coefficient, and since it passes through the origin (0,0), a0=0.

[0060] Incidentally, the above n is an integer of 2 or more, but for the purpose of achieving high precision in drive control, it is preferable that the n is an integer of 3 or more, and the value may be changed as necessary.

[0061] The above formula (1) is expressed as follows, using the position Y1 etc. and the time T1 etc. Y1=a n T1 n +a n―1 T1 n-1 +a n―2 T1 n-2 +···+a1T1 Y2=a n T2 n +a n―1 T2n-1 +a n―2 T2 n-2 +···+a1T2 · · · Y N =a n T N n +a n―1 T N n-1 +a n―2 T N n-2 +···+a1T N can be expressed as follows (Equation 2):

[0062] Here, in the above (Equation 2), the coefficients a1, etc. and the position Y1, etc. are known. Therefore, the time T1, etc. can be calculated based on the calculation processing for the high-order equation. The same can be said about the deceleration characteristics (FIG. 12), and the calculation equation specified in this way can be used as the above-mentioned acceleration / deceleration profile.

[0063] A method for determining the position Y1 etc. will be described with reference to Fig. 13. Fig. 13 is a diagram showing the position detected by the encoder 430 (or 460) in association with the position where the pixel signal is acquired by the signal SH, that is, a diagram showing the relationship between the encoder position and the reading position.

[0064] Here, the target to be read by CIS 30 (or 31) in one go (the target to be read by one drive of a number of pixels arranged in a matrix, i.e., one H-level pulse of signal SH) is defined as a read line. For a read line, if the sub-scanning resolution is SubScanReso [dpi], then one line is 1 / SubScanReso [inch]. For the encoder position, if the encoder resolution is EncReso [dpi], then one slit is 1 / EncReso [slit]. Also, the distance per line is EncReso / SubScanReso [slit].

[0065] Therefore, the position Y1 of the reading line is Y1=1×EncReso / SubScanReso Y2=2×EncReso / SubScanReso · · · Y N = N x EncReso / SubScanReso It should be noted that any of the above parameters may be real numbers, and may be integers or decimals.

[0066] 14 is a diagram showing the accumulation time in the CIS 30. After the position Y1, etc. and the time T1, etc. are determined as described above, the accumulation time in the CIS 30 is calculated. The accumulation time of each line is calculated as the time difference between the lines, such as the time T1, i.e., the accumulation time of the kth row is T k -T k-1 (where k=1 to N). For example, the first row is T1-0 (note that T0=0 because it passes through the origin (0,0)), and the second row is T2-T1.

[0067] In this manner, times T1, etc. are calculated based on positions Y1, etc. that are equally spaced on the document, and a signal SH is generated to correspond to these times T1, etc., making it possible to properly read images even when the motor 420 is in an accelerating or decelerating state.

[0068] The values ​​shown in Fig. 14 may be set for each line by the accumulation start signal generation unit 501 through the above calculation, and a timer using an internal clock may typically be used for the accumulation start signal generation unit 501. Alternatively, the values ​​shown in Fig. 14 may be calculated in advance based on known acceleration / deceleration characteristics. As another example, the values ​​shown in Fig. 14 may be stored in advance in a memory such as RAM 305 and read out for each line, or this may be performed over time based on a timer.

[0069] Fig. 15 is a timing chart showing the state of the signal SH that can be used for driving control of the CIS 30 (or 31) in an accelerating state. Similarly, Fig. 16 shows a timing chart in a decelerating state.

[0070] In the accelerated state, as shown in FIG. 15, the signal SH is generated so that the interval between the H level pulses for each line becomes shorter. In the constant speed state, the signal SH is generated when the interval between the H level pulses becomes constant. In the decelerated state, as shown in FIG. 16, the signal SH is generated so that the interval between the H level pulses for each line becomes longer. That is, according to this embodiment, even in the accelerated state and the decelerated state, it is possible to obtain pixel signals with the same accuracy / quality as in the constant speed state, that is, it is possible to read images while accelerating or decelerating the CIS 30 (or 31). Such image reading in the accelerated state and the decelerated state can be expressed as accelerated reading and decelerated reading, respectively, and can be collectively expressed as accelerated and decelerated reading.

[0071] In this example, the H level pulse of the signal SH is supplied even in the stopped state, so that a so-called blank reading of the signal is performed, and the pixel signal obtained in the stopped state can be discarded. In this case, the signal SH is supplied as an H level pulse having the same period as in the constant speed state, but is not limited to this.

[0072] As described above, servo control is performed when controlling the drive of the motor 420 (or 450), but errors can generally occur when acceleration starts and deceleration ends (when the rotation speed is relatively low). For this reason, it is possible to generate the signal SH and start acquiring the pixel signal when the rotation speed becomes higher than the reference during acceleration, and to suppress generation of the signal SH and end acquiring the pixel signal before the rotation speed becomes lower than the reference during deceleration.

[0073] As described above, the CIS 30 can read images on the document loading platform and by the ADF. Therefore, when the document is to be read up to the edge, it is possible to start accelerating before the CIS 30 is positioned within the document frame and to decelerate so as to stop when the CIS 30 is positioned outside the document frame.

[0074] Additionally, accelerated reading and / or decelerated reading may be omitted depending on the image reading method. For example, in reading on a document loading platform, since the acceleration distance of the CIS 30 may be sufficiently secured, accelerated reading may be omitted while the CIS 30 is moving while accelerating. In reading by the ADF, images of a plurality of documents are generally read in sequence, but the second and subsequent documents are substantially in a constant speed state, so the constant speed state is maintained until the image reading of the last document is completed, and decelerated reading may be omitted.

[0075] If the memory runs out of free space during image reading, the motor 420 is decelerated and stopped, the CIS 30 is returned to the standby position, and when free space is generated in the memory, the motor 420 is accelerated again to resume image reading (switchback processing). In this case, since image reading is resumed from the middle of the document, the acceleration distance / deceleration distance can be secured, and therefore acceleration / deceleration reading is not necessary.

[0076] In addition, in reading by the ADF, the distance between documents can be set short in order to speed up image reading of multiple documents. If the free memory capacity is exhausted during image reading using the ADF (including the case where the free memory capacity is less than a reference value), the motor 420 is decelerated and stopped after image reading of a certain document is completed, and the motor 420 is accelerated again after free memory capacity is generated, so-called inter-page stop can be performed. In this case, since it is difficult to secure a sufficient acceleration distance for image reading of the next document, the image reading can be made more efficient by performing accelerated reading. On the other hand, for documents for which image acquisition has been completed, the motor 420 is decelerated in response to the exhaustion of free memory capacity, so decelerated reading is not necessary.

[0077] 17 is a timing chart showing the control contents when starting image reading when accelerated reading is not required when reading on the document stacking table. In this example, the acceleration of the motor 420 is completed before starting image reading, the rotation speed of the motor 420 is in a constant speed state at a substantially constant speed (within the error range of servo control), and the CIS 30 is driven with the corresponding accumulation time setting. Therefore, in this example, image reading can be started when the position detected by the encoder 430 (or 460) becomes the start position of image reading, but it may be started earlier by, for example, 0.5 lines, taking into account detection errors, control delays, etc.

[0078] In reading by the ADF, deceleration reading is generally not necessary, so when image reading of a single document is completed, the accumulation time may be set to a value corresponding to a predetermined cycle. Since the motor 420 is not accelerated or decelerated while the free memory capacity is equal to or greater than the reference, image reading may be started based on the detection result of the encoder 430 while maintaining a constant speed, as in reading on the document stacking table. If the free memory capacity falls below the reference, the motor 420 is decelerated and stopped, and accelerated reading may be performed when accelerating again.

[0079] As described above, according to this embodiment, the motor driven in image reading is controlled based on a predetermined acceleration / deceleration profile when accelerating and decelerating. Therefore, the timing at which the motor rotation amount (movement distance of the moving object) becomes equal intervals can be calculated or specified by arithmetic processing based on the acceleration / deceleration profile. Therefore, even when the motor is in an accelerating or decelerating state, it is possible to obtain pixel signals with the same accuracy / quality as in a constant speed state, thereby realizing high quality image data and high speed acquisition of the image data.

[0080] In this specification, the present embodiment has been described mainly focusing on the motor 420, but the contents thereof can also be applied to the control of other motors (for example, the motor 450). That is, the contents of the present embodiment can be applied to any element that is to be moved during image reading, and any element that is to be driven in association therewith.

[0081] Furthermore, although this specification has described this embodiment with a focus on acceleration and deceleration of the motor 420, the contents are also applicable to the case where the rotation speed of the motor 420 varies according to a predetermined profile. That is, the profile only needs to be capable of identifying the amount of change when the rotation speed of the motor 420 (movement speed of the moving object) varies, and can also be expressed as a drive speed profile, a rotation speed profile, a movement speed profile, etc., depending on the aspect.

[0082] (program) The present invention may be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in a computer of the system or device read and execute the program. For example, the present invention may be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0083] (others) In the above description, the multifunction device 300 having a recording function using an inkjet recording method is taken as an example, but the recording function is not limited to the above-mentioned embodiment, and may be for manufacturing color filters, electronic devices, optical devices, microstructures, etc., using a predetermined recording method. In addition, the multifunction device 300 may be an image reading device whose main function is a scanning function as long as it is configured to be able to perform the above-mentioned accelerated and decelerated reading. Note that an image reading device may also be expressed as a scanner if it is configured to exclusively support reading on a document mounting table. Furthermore, the multifunction device 300 may be another electrical device whose secondary function is a scanning function.

[0084] The term "recording" in this specification should be interpreted broadly. Therefore, the form of "recording" does not matter whether the object formed on the recording medium is significant information such as characters or figures, and also whether it is visible to humans or not.

[0085] As with the above-mentioned "recording," the term "recording medium" should be interpreted broadly. Therefore, the concept of "recording medium" includes not only commonly used paper, but also any material capable of receiving ink, such as cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc.

[0086] In addition, "ink" should be interpreted broadly, just like the above-mentioned "recording." Therefore, the concept of "ink" includes not only liquid that forms an image, design, pattern, etc. by being applied onto a recording medium, but also incidental liquid that can be used for processing the recording medium, treating the ink (for example, solidifying or insolubilizing the coloring material in the ink applied to the recording medium), etc.

[0087] In the embodiments, each element is named based on its main function, but the functions described in the embodiments may be sub-functions and are not strictly limited to those expressions. Furthermore, those expressions can be replaced with similar expressions. In the same spirit, the expression "unit" can be replaced with "component," "member," "structure," "assembly," "means," etc. Alternatively, they may be omitted.

[0088] (Summary of the embodiment) Some features and variations of the embodiments are as follows: [1] An image reading device comprising: an image reading means for reading an image; a driving means for moving an object when reading the image; and a signal generating means for generating a signal for driving the image reading means, wherein the image reading means reads the image based on a signal generated by the signal generating means while the object is moved by the driving means, thereby acquiring image data, The driving means moves the object so that the object changes at a speed that follows a predetermined driving speed profile; The signal generating means generates signals at timings at which the moving distance of the object becomes equal intervals based on the drive speed profile. 1. An image reading apparatus comprising: [2] The timing at which the signal generating means generates a signal is a timing at which the moving distance of the object becomes equal intervals both while the moving speed of the object is changing and while the moving speed of the object is in a constant state. The image reading device according to [1], [3] the drive speed profile includes an acceleration / deceleration profile, The driving means moves the object so that the object accelerates and decelerates according to the acceleration / deceleration profile. The image reading device according to [2], [4] The image reading means starts reading the image after the object accelerates and before the object reaches a constant speed. The image reading device according to [3], [5] The image reading means ends the image reading after the target decelerates and before the target comes to a stop. The image reading device according to [3], [6] The acceleration / deceleration profile is an n-th degree polynomial, where n is an integer equal to or greater than 2. The image reading device according to any one of [3] to [5], [7] The acceleration / deceleration profile is an n-th degree polynomial, where n is an integer equal to or greater than 3. The image reading device according to any one of [3] to [6], [8] the image reading device is a scanner, the image reading means is an image sensor, The object is the image sensor. The image reading device according to any one of [3] to [7], [9] During acceleration of the object, the image reading means inhibits the start of the image reading. The image reading device according to [8],

[10] the image reading device is an ADF, The image reading means reads the image of a document, The object is the manuscript. The image reading device according to any one of [3] to [7],

[11] the document is one of a plurality of documents; The image reading means completes the image reading for the plurality of documents while the driving means maintains the object at a constant speed. The image reading device according to

[10] ,

[12] A program for causing a computer to function as each of the means of the image reading device according to any one of [1] to

[11] .

[0089] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0090] 300: multifunction device (image reading device), 30-31: CIS, 420: motor, 450: motor.

Claims

1. An image reading device comprising: an image reading means for reading an image; a driving means for moving an object during the image reading; and a signal generating means for generating a signal for driving the image reading means, wherein the image reading means reads the image based on the signal generated by the signal generating means while the object is moved by the driving means, and image data is acquired by the image reading means. The driving means moves the object so that the object changes speed according to a predetermined driving speed profile. The signal generation means generates signals based on the drive speed profile at timings where the movement distance of the target is at equal intervals. The timing at which the signal generating means generates a signal is when the distance traveled by the object is at equal intervals, both while the object's moving speed is changing and while the object is moving at a constant speed. An image reading device characterized by the following.

2. The aforementioned drive speed profile includes an acceleration / deceleration profile, The driving means moves the object so that it accelerates or decelerates according to the acceleration / deceleration profile. The image reading device according to feature 1.

3. The image reading means starts reading the image after the target has accelerated but before it reaches a constant velocity state. The image reading device according to feature 2.

4. The image reading means terminates the image reading after the target has decelerated but before it comes to a complete stop. The image reading device according to feature 2.

5. The acceleration / deceleration profile is an n-th degree polynomial where n is an integer greater than or equal to 2. The image reading device according to feature 2.

6. The acceleration / deceleration profile is an n-th degree polynomial where n is an integer greater than or equal to 3. The image reading device according to feature 2.

7. The image reading device is a scanner, The aforementioned image reading means is an image sensor, The aforementioned object is the image sensor. The image reading device according to feature 2.

8. During the acceleration of the target, the image reading means suppresses the start of the image reading. The image reading device according to feature 7.

9. The aforementioned image reading device is an ADF, The image reading means performs the image reading on the document, The subject is the aforementioned manuscript. The image reading device according to feature 2.

10. The aforementioned manuscript is one of several manuscripts. The image reading means completes the image reading of the plurality of documents while the driving means maintains the object in a constant-speed state. The image reading device according to feature 9.

11. A program for causing a computer to function as one of the means of an image reading device according to any one of claims 1 to 10.

Images