JP2005006003A - Transport body detector and original reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise the detecting accuracy of the existence switching timing for detecting a transport body by a sensor. <P>SOLUTION: The transport body detector comprises a sensor (232) for detecting the existence of a transport body at a specified position on a transporting way of transporting mechanisms (220-223) driven by a motor (227), means (43-45/43, 63-65) for detecting a first timing (t5: g)with a switched state continuing for a set time (m periods of Lsync) after the existence detection is switched, on the basis of an existence detection signal delayed by a specified time (T: Ns) from the sensor (232), means (41, 49, 50, 51) for measuring the number (Npc) of motor pulses each generated per specified small angle of motor rotation for the specified time (T), and means (47, 52, 53, 54, 55, 78-81/47, 52, 53, 74, 75, 78-80, 82) for calculating the timing (t1) of the switching using the number of pulses (Npc) measured by the measuring means and the first timing (t5: g). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer object detection device that detects a timing at which an object transferred by a transfer mechanism reaches a predetermined position on a transfer path or a timing at which the object moves away from the predetermined position, and a document reading apparatus that uses the detection object. The transported object detection device can be used for tracking the position of a document to be transported or paper (transfer paper) in, for example, a document reading device, a printer, a copying machine, and a facsimile. It is also used when it is desired to track an object position with relatively high accuracy on the transfer path.
[0002]
[Prior art]
Japanese Patent Laid-Open No. 2000-92281 measures the number of motor pulses of a stepping motor while a carriage that scans a document moves a predetermined distance in order to accurately adjust the document reading magnification. An image reading apparatus is described in which the motor pulse period is adjusted to match the reference value.
[0003]
Japanese Patent Application Laid-Open No. 2000-165612 discloses a sheet-through type document reading system including a transport mechanism that transports a document in a direction across the field of view of an image reading optical system and a drive control unit that controls driving of the transport mechanism. An apparatus is described. The document reading device determines a malfunction prevention time for detecting the leading and trailing edges of each document for each document conveyance speed and stores it in a memory, reads the malfunction prevention time corresponding to the document conveyance speed to be executed from the memory, This is used to detect the arrival of the original (leading edge) at the sensor and the separation of the original (rejecting the trailing edge).
[0004]
[Patent Document 3] Japanese Patent Application Laid-Open No. 2001-127965 writes image data obtained by reading a document into a memory, reads out and outputs the image data in the memory, and stops driving the stepping motor when the memory is full. In the start / stop control in which the driving is resumed when a vacancy is generated, electronic image reading is performed at the stop and at the start in order to eliminate the discontinuity in the read image data at the joint between the stop and start. It has been proposed to make the time difference from the excitation timing of the stepping motor the same.
[0005]
Conventionally, even when the document sensor changes to ON (document detection) or OFF (document non-detection) during slow-up / down of the document transport motor, even when the document sensor changes to ON or OFF during constant speed driving. When the same state continues at a constant distance (or time) from the timing, it is determined to be ON or OFF for the first time. In this case, the actual document position varies when it is recognized that the document sensor is actually switched ON or OFF by software control, and as a result, the reading destination rear end position varies.
[0006]
With reference to FIG. 10, how the conventional soft control determines the ON change timing of the document sensor for positioning the leading and trailing edges of the document will be described. First, in the software control, it is checked whether the document sensor is ON or OFF at every certain interval T. This may be a periodic interrupt or a resident task. FIG. 10 describes an example in which the detection signal of the document sensor is read to check whether it is ON or OFF by a pulse interrupt to the CPU in response to a fixed-cycle pulse generated at a constant interval T called Bsync. . Then, for example, each time a Bsync pulse is generated, it is checked and it is determined that the document sensor is turned on or off at the time when the continuous ON state or OFF state continues n times. This is control for removing timing errors due to chattering of the document sensor. When n = 2, “detection check 2” detects the first ON, and “detection check 3” detects the second ON, so “detection check 3” and “detection check 2” It is determined that the document sensor is turned on at the timing.
[0007]
The timing at which the document sensor actually shifts from OFF to ON is during Bsync (between detection checks 1 and 2) (n × Bsync (T)) before the time when ON is confirmed (“detection check 3”). You can know that. If it is assumed that at the time of “detection check 3”, the document sensor is turned on at the exact middle timing between detection checks 1 and 2, an error will actually occur by time D. In the worst case, a time error of (1/2) · T occurs. Of course, D may be ignored if T is sufficiently short relative to the transfer rate. However, if T is shortened, the overall software performance deteriorates. Therefore, with the recent increase in reading speed, the determination shown in FIG. 11 has been introduced.
[0008]
In FIG. 11, the ON / OFF state of the original sensor is checked and stored in the memory at a time interval (Lsync) obtained by dividing the period T checked by the software into 16 equal parts, for example, and the result is read into the CPU at the period T. Thus, the ON timing is determined from the ON / OFF distribution. According to this, it is not necessary to shorten the period T in which the software intervenes, and the accurate position of the document can be known. In short, the history of the detection signal of the original sensor during the T period in the T cycle (transition and transition of Lsync step) is checked. This history is, for example, a register of 1 word (2 bytes), bit 16 (most significant bit: leftmost in FIG. 11) is the oldest detection signal, and bit0 (lowest bit: rightmost) is Assuming that the detection signal is the newest, in the example of FIG. 11, the document sensor actually shifts from OFF to ON during the period T of the software control 1, and the software checks and recognizes it in the software control 2. is doing. This indicates that the detection signal from bit 4 to bit 0 is ON (original is present), and that from bit 15 to bit 5 is OFF (original is not present). Therefore, at the time of software control 2, it is possible to know that the detection of the document sensor has shifted from OFF to ON when 11 Lsync of software control 1 before that time has elapsed. Of course, in this case as well, it is necessary to remove chattering, but if ON continues for a time longer than the cycle of m × Lsync, it may be determined that it is ON. m is the minimum number of consecutive ONs (number of pulses of Lsync) that is considered to be stable to ON.
[0009]
[Problems to be solved by the invention]
In this case, the time point 5 pulses before the Lsync pulse from the start point (Bsync) of the soft control 2 is determined as the document start end arrival timing. However, when the document transfer speed is not the set constant speed, the document start end based on the document start end arrival timing is determined. In the transfer position tracking, a positional deviation occurs. For example, after the detection of the document sensor is switched from OFF to ON, the first timing when the m sync pulse is generated is, for example, the count of the Lsync pulse or the motor pulse is started at the time of starting the document transfer, and the first timing In this case, it can be determined by saving the count data, or by starting counting up the Lsync pulse or the motor pulse by the tracking counter. Then, timing data actually switched to ON is obtained by subtracting m from the saved value. Alternatively, by adding m (or the number of motor pulses generated while the Lsync pulse is generated by m pulses) to the count value of the tracking counter, the elapsed time (Lsync count value) or the moving distance after actually switching to ON (Motor pulse count value) is obtained.
[0010]
However, if the original speed while the m sync pulse is generated by m pulses deviates from the set constant speed, the amount of movement of the original while the m sync pulse is generated is different from the amount of movement at the preset constant speed, The difference is a positional deviation for detecting the leading edge of the document. For example, if the motor that drives the transfer mechanism detects the document start edge during slow-up or slow-down, there is a possibility that the position of the document leading edge will be misaligned. For the same reason, the motor that drives the transfer mechanism slows down. Alternatively, if the document tail end is detected during the slow-up, there is a possibility that the document tail end position detection is displaced.
[0011]
An object of the present invention is to increase the detection accuracy of the presence / absence switching timing in detecting a moving object by a sensor.
[0012]
[Means for Solving the Problems]
(1) A sensor (232) for detecting the presence or absence of a transfer object at a predetermined position in a transfer path of a transfer mechanism (220 to 223) driven by a motor (227);
Based on the presence / absence detection signal delayed by a predetermined time (T: Ns) of the sensor (232), the first timing (t5) when the presence / absence detection is switched and the state after the set time (Lsync m cycles) is switched continues. : Means for detecting g) (43-45 / 43, 63-65);
Means (41, 49, 50, 51) for measuring the number (Npc) of generation of one motor pulse per predetermined small angle of rotation of the motor during the predetermined time (T);
Means (47, 52, 53, 54, 55, 78 to 81) for calculating the switching timing (t1) using the number of occurrences (Npc) measured by the measuring means and the first timing (t5: g). / 47, 52, 53, 74, 75, 78-80, 82);
A moving object detection device (Fig. 5).
[0013]
In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the corresponding matter of the Example shown in drawing and mentioned later in parentheses was added as reference for reference. The same applies to the following.
[0014]
According to this, the said detection means (43-45 / 43, 63-65) 1st timing (t5) when the state which the presence / absence detection of the sensor switched and the post-set time (m cycle of Lsync) switched was continued. : G), the measuring means (41, 49, 50, 51) measures the number of motor pulses generated (Npc) during a predetermined time (T: Ns) when the switching is performed. Yes. When the number of generated pulses (Npc) is compared with the number of motor pulses (Np) generated during the predetermined time (T) when the motor (227) is driven at a set constant speed, during the predetermined time (T) It can be seen whether the motor speed is equal to or different from the set constant speed, and the ratio (Npc / Np) of both represents the motor speed ratio during the predetermined time (T) with respect to the set constant speed. A predetermined time (T) of a time (M = m + g) from the first time (t5: g) to the end point (t6) of the predetermined time (T: Ns) before the set time (m cycle of Lsync) (t4). ) (M / (Npc / Ns)) multiplied by the number (Npc) of motor pulses generated during a predetermined time (T: Ns) by a ratio (M / T = (m + g) / Ns = M / Ns). The motor pulse during the time (M = m + g) from the set time (m cycle of Lsync) minutes (t4) to the end point (t6) of the predetermined time (T: Ns) before the first timing (t5: g) The number of occurrences is estimated, and the second timing (t1) before the end point (t3) of the predetermined time (T: Ns) ahead is determined as the actual switching timing. Here, counting up of the motor pulse is started at the end point (t3) of the preceding predetermined time (T: Ns), and the product (M · (Npc / Ns)) is added to the count value (Lptn / Lpbn). , The sum (LPT / LPB) represents the transfer distance (tip / rear end position) after the front end / rear end of the transfer object is actually detected by the sensor. Even when switching occurs when the motor speed is different from the set constant speed, the switching timing is detected more than when the timing before the first msync pulse of Lsync is set to the actual switching timing. Becomes accurate.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(1a) The calculation means (47, 52, 53, 54, 55, 78 to 81/47, 52, 53, 74, 75, 78 to 80, 82) Ratio (M / Ns) of time (M = m + g) from the preset time (m period of Lsync) minutes (t4) to the end point (t6) of the predetermined time (T: Ns) from one timing (t5: g) And the second timing (t1) before the start point (t3) of the predetermined time (T: Ns) by the product (M · Npc / Ns) of the number of occurrences (Npc) measured by the measuring means. The moving object detection apparatus according to (1), which calculates the switching timing (FIG. 5).
[0016]
(2) A sensor (232) for detecting the presence or absence of a transfer object at a predetermined position in a transfer path of a transfer mechanism (220 to 223) driven by a motor (227);
Based on the presence / absence detection signal delayed by a predetermined time (T) of the sensor (232), the first timing (t5: g) when the presence / absence detection is switched and the set time (Lsync m cycles) is switched. ) Detecting means (43-45 / 43, 63-65);
Means (50) for counting the number of occurrences of one motor pulse per rotation of the motor at a predetermined small angle during each period of the fixed period pulse (Lsync);
Means (76, 77) for holding a count value during each period; and
Means (78 to 84, 54, 55/78 to 84, 74, 74) for calculating the switching timing (t1) using each count value of the holding means (76, 77) and the first timing (t5). 75);
A moving object detection device (FIG. 8).
[0017]
According to this, the said detection means (43-45 / 43, 63-65) 1st timing (t5) when the state which the presence / absence detection of the sensor switched and the post-set time (m cycle of Lsync) switched was continued. : G) is detected, the holding means (76, 77) holds each count value during the predetermined time (T: Ns). The sum of the count values during the predetermined time (T: Ns) is the number of motor pulses generated during the predetermined time (T: Ns). Each occurrence occurred during a period (M = m + g) from the set time (m cycle of Lsync) minutes (t4) to the end point (t6) of the predetermined time (T: Ns) from the first timing (t5: g) The sum (partial sum) of the count values is the number of motor pulses (NpM) generated during the period (M). Accordingly, the second timing (t1) before the start point (t3) of the predetermined time (T: Ns) is determined as the actual switching timing. Here, the count-up of the motor pulse is started at the start point (t3) of the predetermined time (T: Ns), and the sum (partial sum NpM) is added to the count value (Lptn / LPbn). LPB) represents the transfer distance (front end / rear end position) after the front end / rear end of the transfer object actually reaches the sensor (232). Even when switching occurs when the motor speed is different from the set constant speed, the switching timing is detected more than when the timing before the first msync pulse of Lsync is set to the actual switching timing. Becomes accurate.
[0018]
(2a) The calculation means (78 to 84, 54, 55/78 to 84, 74, 75) is predetermined (t4) before the set time (m cycle of Lsync) from the first timing (t5: g). The sum (NpM) of each count value generated during the period (M = m + g) until the end point (t6) of time (T: Ns) is before the start point (t3) of the predetermined time (T: Ns). The moving object detection device according to (2), wherein the second timing (t1) is calculated as the switching timing (FIG. 8).
[0019]
(3) The first timing detection means (43 to 45/43, 63 to 65) is a memory for reading and holding the presence / absence detection signal of the sensor (232) in synchronization with a fixed period pulse (Lsync). The same between the means (43) and the presence / absence switching of the presence / absence detection signal of each section of the memory means (43) after the delay (T) of the number of periods of the fixed period pulse corresponding to the predetermined time (T) Any one of the above (1) to (2a), including continuous detection means (44, 45/63 to 65) for detecting a continuous (m) of the signal corresponding to the set time (m cycle of Lsync) The transferred object detection apparatus described (FIG. 5 / FIG. 8). According to this, the first timing can be detected in the manner shown in FIG. 11 and described above.
[0020]
(4) The moving object detection device includes tracking count means (42/62) that starts measuring the number of generated motor pulses (Lptn / Lpbn) at the start point (t3) of the predetermined time (T: Ns), and , Calculated for the period (M = m + g) from the set time (m cycle of Lsync) minutes (t4) to the end point (t6) of the predetermined time (T: Ns) from the first timing (t5: g) (3) including means (55/75) for adding the motor pulse generation number (M · Npc / Ns, NpM) to the measured value (Lptn / Lpbn) of the tracking count means (42/62). The transferred object detection apparatus described (FIG. 5 / FIG. 8).
[0021]
According to this, after the first timing, position data representing the amount of transfer (transfer distance) after the tracking count means (42/62) has detected the front end / rear end of the transferred object by the sensor (232), that is, tracking. Data is obtained.
[0022]
(5) The detection means (43 to 45/43, 63 to 65) detects an ON change from presence to absence of a transfer object (43 to 45) and detects an OFF change from presence to absence (43, 63 to 65); the calculation means also includes one that calculates the timing of ON change and one that calculates the timing of OFF change; any one of (1) to (4) above The moving object detection apparatus as described. According to this, both the front end position tracking and the rear end position tracking of the transfer object can be executed.
[0023]
(6) In a sheet-through type document reading apparatus comprising an image reading optical system, a transfer mechanism for transferring a document in a direction crossing its visual field, and a drive control means (40) for controlling the drive of the transfer mechanism.
The transport object detection apparatus according to any one of (1) to (5) is provided, the transport object is a document to be scanned, and the transport mechanism (220 to 223) is a reading field of the image scanning optical system. Is a document transport mechanism (220 to 223) that feeds a document in a direction across the document, a motor that drives the mechanism is a step motor (227), and the sensor is in the document transport direction by the transport mechanism (220 to 223). A document sensor (232) for detecting whether or not there is a document at a predetermined position upstream of the reading visual field, and the drive control means (40) refers to the second timing calculated by the transported object detection device. An original reading apparatus characterized by controlling driving of a mechanism (220 to 223).
[0024]
According to this, in the detection of the leading edge of the document and the detection of the trailing edge of the document in the document reading device, the effect described in any one of the above (1) to (5) is obtained, and the document transport control is further performed. Can be done accurately.
[0025]
(7) In a sheet-through type original reading apparatus including an image reading optical system, a transfer mechanism for transferring an original in a direction crossing the field of view, and a timing control means for controlling image reading of the image reading optical system.
The transport object detection apparatus according to any one of (1) to (5) is provided, the transport object is a document to be scanned, and the transport mechanism (220 to 223) is a reading field of the image scanning optical system. Is a document transport mechanism (220 to 223) that feeds a document in a direction across the document, a motor that drives the mechanism is a step motor (227), and the sensor is in the document transport direction by the transport mechanism (220 to 223). A document sensor (232) for detecting whether or not there is a document at a predetermined position upstream of the reading field, and the timing control unit controls image reading with reference to a second timing calculated by the moving object detection device. A document reading apparatus characterized by:
[0026]
According to this, the function and effect described in any one of the above (1) to (5) can be obtained in the document leading edge detection and / or document trailing edge detection in the document reading apparatus, and the document image reading control can be performed. It can be done more accurately.
[0027]
(8) Image forming means (100) for forming an image represented by the image data on a sheet;
The document reading device (10) according to (6) or (7); and
An image forming apparatus comprising: image data processing means (IPP) for converting image data generated by the original reading apparatus by original reading into image data for image formation by the image forming means.
[0028]
(9) In a sheet-through type document reading apparatus, a document transporting step motor driving mechanism and a document sensor, and an apparatus using a control method for determining a reading destination rear end position based on ON / OFF of the sensor, A document reading apparatus capable of reducing a deviation in a reading destination rear end position even if a sensor is switched ON / OFF during a slow-up / down of a transfer step motor. Even when the slow-up / down speed curve is long in time, it is possible to reduce the reading end edge position shift.
[0029]
(10) The apparatus according to any one of (6) to (9), wherein the reading destination rear end position can be detected for each reading line density. Even when the motor slow-up / down speed curves are different, it is possible to reduce the reading end position deviation.
[0030]
Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
[0031]
【Example】
-1st Example-
FIG. 1 shows the appearance of a multi-function full-color digital copying machine according to an embodiment of the present invention. This full-color copying machine is roughly constituted by units of an automatic document feeder (ADF) 30, an operation board 20, a color scanner 10, a color printer 100, and a paper feed bank 35. A finisher 34 with a tray capable of stacking a stapler and imaged paper, a double-sided drive unit 33, and a large-capacity paper feed tray 36 are mounted on the printer 100.
[0032]
The in-flight system controller 630 (FIG. 3) is connected to a LAN (Local Area Network) connected to a personal computer PC, and the facsimile control unit FCU (FIG. 3) is connected to a telephone line PN (facsimile communication line). The exchange PBX is connected. The printed paper of the color printer 100 is discharged onto the paper discharge tray 108 or the finisher 34.
[0033]
FIG. 2 shows an outline of the document reading mechanism of the document scanner 10. Reference numeral 220 denotes a first drive roller that conveys a document inserted from the document insertion slot to a reading unit. Reference numeral 228 denotes an imaging device that reads an image of the document conveyed by the first drive roller 220. Reference numeral 229 denotes a document. It is a guide.
[0034]
Reference numeral 221 denotes a second drive roller that guides and conveys the document that has been read in the direction opposite to the insertion slot. A first driven roller 222 is in pressure contact with the outer periphery of the first drive roller 220 to apply a conveying force to the document.
[0035]
A step motor 227 drives the first drive roller 220 and the second drive roller 221, and a second driven roller 223 presses the second drive roller 221 and conveys the document.
[0036]
A paper sensor 233 for detecting the inserted document is provided inside the document insertion opening, and a document sensor 232 is provided between the first conveyance roller 220 and the imaging device 228. When the paper sensor 233 detects a document, the scanner control circuit 206 (FIG. 4) starts driving the motor 227. When the original is bitten by the rollers 220 and 222 and conveyed by them, the original sensor 232 detects the original. The scanner control circuit 206 and the timing control circuit 211 start control for outputting the image reading signal of the imaging device 228 in response to the detection of the document start edge of the document sensor 232.
[0037]
Reference numeral 207 denotes a reading document support table that can be rotated in a horizontal position, and 208 is a discharge document support table that can be rotated in a horizontal position. An ADF 30 is attached to the document scanner 10. When a document is loaded in the ADF 30, the scanner control circuit 206 drives the motor 227 in response to a start key operation on the operation board 20 or in response to a start instruction from the personal computer PC. The paper feed roller 242 and the transport rollers 243 and 244 are driven by the step motor 227 similarly to the drive rollers 220 and 221, and the transport speed of the transport roller 244 is the same as the transport speed of the drive rollers 220 and 221. The conveyance speed of 242 and the conveyance roller 243 is slightly low.
[0038]
In this state, when the trailing edge of the first page of the document on the document tray 241 passes the transport roller 243, the next document is also sent by the paper feed roller 242. A gap is generated between the (preceding paper) and the second sheet (following paper). In recent years when high-speed reading is required, the gap between pages is designed to be as short as possible to improve the speed at the time of multi-page reading.
[0039]
Next, document transfer control will be described.
[0040]
(1) When a document is inserted from the manual feed table 208, when the paper sensor 233 detects this, the step motor 227 is driven to pull the manual document by the roller 220, and when the leading edge is detected by the document sensor 232, The leading edge tracking is started, and the conveyance is stopped at a temporary stop position determined between the detection position of the document sensor 232 and the reading field of view (reading line) of the imaging device 228. Then, the transfer speed is determined according to the reading conditions, and the step motor 227 is driven at the speed.
[0041]
Then, the image reading by the image pickup apparatus is started from the timing when the predetermined distance is transferred. When the document sensor 232 detects the passage of the tail end of the document, tracking of the tail end is started, and image reading is stopped at the timing when the tail end passes through the reading field of the imaging device 228, and the tail end is downstream of the driving roller 221. The driving of the motor 227 is stopped at the timing when the operation is lost.
[0042]
(2) Next, document transfer control during image reading by document feeding from the ADF 30 will be described.
[0043]
(2-1) ADF pre-feed operation
In the operation mode in which the document set on the ADF document table 241 is transferred to the temporary stop position, the conveyance of the document on the ADF document table 241 is started, and when the document sensor 232 detects the leading edge of the document, the document start edge tracking is started. Then, the document is stopped at the timing when the document starting edge reaches the temporary stop position. The ADF pre-feed operation is executed not only for the first page but for each page. However, if the document has already been detected by the document sensor 232 when the ADF prefeed operation is started, the ADF prefeed operation is not executed.
[0044]
(2-2) Reading operation
The document transferred in the ADF pre-feed operation is started to be re-transferred from the temporary stop position at a transfer speed corresponding to the linear density (DPI or reading magnification) specified by the user, and an image is captured by the imaging device 228. read. As software control, image reading is started at a timing when a predetermined length has been transferred from the pause position and read for a predetermined length, or when the document sensor 232 is switched to non-detection (OFF) of the document. After the tail end position tracking is started and read for a preset length, it is transported for a preset length and then stopped. This stop position is a stamp stamp standby position. Therefore, the operation of transferring to the stamping position is also included in this reading operation control.
[0045]
(2-3) Paper discharge operation
In the paper discharge operation, the motor is rotated in the forward rotation direction by a preset pulse, and the final page of the original is discharged. This operation is not executed in the middle of multi-page reading, but is operated when only the last page is discharged. Therefore, pages other than the last page are naturally discharged by the ADF prefeed operation and the reading operation of the next page.
[0046]
FIG. 3 shows a system configuration of image reading, image processing, image storage and image formation of the copying machine shown in FIG. A reading unit 11 that optically reads a document of the color document scanner 10 scans the document with a lamp 232 and forms a document image on a CCD 207 of an SBU (sensor board unit). An original image, that is, reflected light irradiated on the original is photoelectrically converted by the CCD 207 to generate R, G, B image signals, converted to RGB image data on the SBU, shading corrected, and output I / F (interface) 12 The image data is sent to an image data processor IPP (Image Processing Processor; hereinafter simply referred to as IPP) via the image data bus.
[0047]
The IPP performs separation generation (determination of whether an image is a character area or a photographic area: image area separation), background removal, scanner gamma conversion, filter, color correction, scaling, image processing, printer gamma conversion, and gradation processing. IPP is a programmable arithmetic processing means for performing image processing. Image data transferred from the scanner 10 to the IPP is corrected for signal deterioration (scanner signal deterioration) accompanying quantization into an optical system and a digital signal by the IPP, and is written in the frame memory 601.
[0048]
The system controller 630 has functions of a plurality of applications such as a scanner application, a facsimile application, a printer application, and a copy application, and controls the entire system. The operation panel control device 631 is a device that decodes the input of the operation board 20 and displays the settings of this system and the contents of the status. The image data bus / control command bus is a bus through which image data and control commands are transferred in a time division manner.
[0049]
The CPU 605 of the system controller 630 controls the system controller 630. In the ROM 604, a control program for the system controller 630 is written. A RAM 603 is a working memory used by the CPU 605. The NVRAM 602 is a non-volatile memory, and stores information on the entire system, such as a sub-scanning magnification adjustment value, a main scanning magnification adjustment value, and the like.
[0050]
The external device communication control 606 controls communication with an external device (for example, the same type of copying machine, image scanner, personal computer, printer, facsimile) that requests image reading, image storage, or image printing, and is connected to a network. The physical I / F is controlled. When the external device communication control 606 connected to the network receives data from the network, only the content of the communication data is sent to the system I / F 607 from an electrical signal. In the system I / F 607, the received data is logically converted in accordance with a prescribed protocol and sent to the CPU 605. The CPU 605 determines and processes the logically converted received data. When the CPU 605 transmits data to the network, the transmission data is transmitted to the system I / F 607 and the external device communication control 606 in the reverse order of reception, and is transmitted as an electric signal on the network.
[0051]
The system I / F 607 controls the transfer of document reading data, facsimile reception data, personal computer document data (printing commands), and image data for printing personal computer document data, which are processed in the system according to a command from the CPU 605. Image data) and transfer. The work memory 600 is a working memory for image development (conversion from document data to image data) used in the printer. The frame memory 601 is a working memory that temporarily stores image data of a read image and a written image that are printed immediately while power is being supplied.
[0052]
The HDDC 650 is a hard disk and its controller that can store application programs, image data of read images and write images, that is, image data, and print document data even when power supply is stopped. Image data and document data may be encoded or dot images. The FIFO buffer memory 609 performs data transfer rate conversion when writing an input image to the frame memory 601. In other words, temporary storage of data that absorbs the difference between the data sending / receiving timing of the transfer source and the transfer destination, the difference in the data amount of the transfer unit, the transfer speed difference, etc., and accepts the data at the transfer timing and speed of the transfer source, Data is sent out at the transfer timing and speed of the transfer destination. Similarly, the FIFO buffer memory 608 performs speed conversion when transferring the image data of the frame memory 601 as an output image.
[0053]
The memory controller 610 controls input / output of images between the frame memory 601 and the HDDC 650 and the bus without the control of the CPU 605. Further, the image stored in the HDDC is edited and processed using the frame memory 601 in accordance with a command received by the input device 614 of the operation board 301. The memory controller 610 reads image information from the HDD of the HDDC 650 to the work memory 600 or the frame memory 601 and changes the image printing direction on the transfer paper, image rotation, image combination editing mainly by the image data address changing operation. Various kinds of images by density conversion by addition / subtraction / division / division of image data, image trimming and synthesis by logical product operation or logical sum operation of image data, and writing of image information processed in this way to the HDD. Processing and editing can be performed. The image reading unit 624 performs image reading scaling, and the image writing unit 623 performs printing scaling.
[0054]
The CPU 617 performs input / output control of the operation board 20. That is, the input reading and display output of the operation board 20 are controlled. In the ROM 616, a control program for the operation board 20 is written. A RAM 618 is a working memory used by the CPU 617. Reference numeral 614 denotes an input device that allows the user to input system settings by operating the input keys and the input panel of the operation board 20. The display device 615 is provided on the operation board 20 and displays the setting contents and status of the system to the user, and includes an indicator lamp and a display panel. The basic magnification adjustment values for main scanning and sub-scanning are measured by a sample image in the system adjustment process, and are set by the operation panel control device 611. In addition, the magnification adjustment values for the main scanning and sub-scanning four-sided borders are confirmed by the user or maintenance personnel from the printed image to see if there are any missing images or blank spaces. 20 is set.
[0055]
FIG. 4 shows the configuration of the electrical system for image reading of the scanner 10. An electrical signal, that is, an analog image signal output from the CCD image sensor of the imaging device 228 is amplified by a signal processing circuit and converted into a digital image signal, that is, image data by A / D conversion. This image data is subjected to correction processing by the shading correction circuit and output to the IPP.
[0056]
The scanner control circuit 206 controls the lamp control circuit 205, the timing control circuit 211, and the motor control unit 260 in accordance with instructions from the system controller 630 and the process controller 131. The lamp control circuit 205 controls on / off of the exposure lamp 232 (232a, 232b) in accordance with an instruction from the scanner control circuit 206, and also adjusts the brightness (exposure) of the exposure lamp 232 to the illuminance (light quantity) instructed by the shading correction circuit. (Time series average value or smooth value). Reference numerals 232a and 232b may be collectively indicated by reference numeral 232.
[0057]
The motor control unit 260 controls the step motor 227 in accordance with an instruction from the scanner control circuit 206. The timing control circuit 211 generates various signals in accordance with instructions or control signals from the scanner control circuit 206, the system controller 630 (CPU 605) and the process controller 131. That is, when image reading is started, the CCD image sensor 207 is supplied with a transfer gate signal for transferring data for one line to the shift register and a shift clock pulse for outputting the data of the shift register bit by bit, and the system controller. For 630, a pixel synchronization clock pulse CLK, a line synchronization signal LSYNC, and a main scanning effective period signal LGATE are output. This pixel synchronization clock pulse CLK is substantially the same signal as the shift clock pulse given to the CCD image sensor 207. The line synchronization signal LSYNC is a signal corresponding to the line synchronization signal MSYNC output from the beam sensor of the image forming unit 135 of the printer 100, but output is prohibited when the image is not read. The main scanning effective period signal LGATE becomes high level H at a timing at which the image signal output from the CCD image sensor 207 can be regarded as effective.
[0058]
When the scanner control circuit 206 receives a reading start instruction from the process controller 131, the scanner control circuit 206 instructs the lamp control circuit to turn on the exposure lamp 232, instructs the motor control unit 40 to transfer the document, and starts the document generated by the motor control unit 40. The timing control circuit 211 is controlled based on the tracking data and the document tail edge tracking data, and reading of the CCD image sensor 207 is started. Further, the sub-scanning effective period signal FGATE is set to a high level H (outside the document area). This signal FGATE is switched to L indicating the inside of the document area when the document start edge tracking data indicates the timing at which the document start edge is in the reading field of view of the imaging device 228. When the document tail end tracking data indicates the timing at which the document tail exits the reading field of the image pickup device 228, the sub-scanning effective period signal FGATE is returned to H indicating the outside of the document area.
[0059]
FIG. 5 shows the motor control unit 40 shown in FIG. 4. Based on the document detection signal of the document sensor 232, the timing at which the document start edge reaches the detection position of the document sensor 232 is detected and the document start edge tracking data LPT is obtained. An outline of a function for generating the document tail edge tracking data LPB by detecting the timing at which the document tail edge (rear edge) passes the detection position of the document sensor 232 is shown in the form of a block diagram.
[0060]
The fixed-cycle pulse Lsync given as a count pulse to the frequency division counter 41 is a line synchronization pulse having a line reading cycle of the CCD image sensor of the imaging device 228 or an integer multiple or a fraction of an integer, and counts this pulse. Thus, the number of line outputs of the CCD image sensor can be obtained. When an image is read by the CCD image sensor while the document is transferred at a constant speed, the document transfer amount during one cycle of Lsync is constant. Therefore, the count value of Lsync is equal to the document transfer amount (distance). Represents a proportional value. However, when the document transfer speed fluctuates, the count value of Lsync deviates from the value proportional to the document transfer amount (distance).
[0061]
On the other hand, the step motor applies a phase excitation pulse to the motor driver, so that the motor driver applies the drive pulse to the step motor, whereby the step motor is rotated and the amount of rotation is proportional to the number of phase excitation pulses. When the phase excitation pulse or its frequency-divided pulse is expressed as a motor pulse, the count value of the motor pulse of the step motor 227 also represents the transfer amount (distance) of the document transferred by the motor 227. Since one cycle of the motor pulse means transport of the document at a certain distance, even if the motor pulse cycle is changed for slow-up or slow-down, the count value of the motor pulse is equal to the transport amount of the document ( (Distance) is expressed accurately.
[0062]
Therefore, in this embodiment, until the sensor 232 detects the starting edge of the document, the frequency dividing counter 41 clears the starting edge tracking counter 42 to zero value data in response to a carry pulse generated at a fixed period (predetermined time T). Then, the clear & start operation to start counting up the motor pulses is repeated. However, when the document start edge is detected by the document start edge arrival check that is delayed by a predetermined time T from the document detection signal of the sensor 232, the clear & start is suspended. Then, the count-up of the motor pulse by the start end tracking counter 42 is continued. At the count value Lptn, the time M from the set time (m cycle of Lsync) t4 to the end point t6 of the predetermined time T from the first timing t5 (FIGS. 6 and 7) when the document start edge is detected by the document start edge arrival check. The product M · (Npc / Ns) obtained by multiplying the number Mpc of motor pulses generated during the predetermined time T by the ratio M / T = (m + g) / Ns = M / Ns with respect to the predetermined time (T) is added. The tip tracking data LPT is generated.
[0063]
When the transfer of the manual feed document or the ADF 30 document is started, a start signal (H pulse) arrives and is applied to the clear input terminals of the frequency dividing counter 41 and the counter 50. The counter 50 was used to count the number Npc of motor pulses generated during a predetermined time T (16 periods of Lsync). In response to the start pulse, the counters 41 and 50 initialize the count data to zero value data, and start counting up the Lsync pulse and the motor pulse that arrive at the count input terminal CK from the time when the start pulse disappears.
[0064]
The frequency division counter 41 counts the line synchronization pulse Lsync, generates a carry pulse when the count value reaches 16, initializes its own count data to 0 value data, counts up the line synchronization pulse Lsync again, Repeat. The motor pulse counter 50 is cleared by a carry pulse generated by the frequency dividing counter 41, initializes the count data to zero value data, and counts up the motor pulse again. The motor pulse count value Npc in the T period (predetermined time) immediately before the conversion is set (latched: stored) in the latch 51.
[0065]
Reference is also made to FIG. The document detection signal S232 of the document sensor 232 is supplied to the shift register 43 having a serial 16-stage configuration, and is taken in synchronization with the line synchronization pulse Lsync and sequentially shifted, and 16 pulses (T) of the line synchronization pulse Lsync. And output to the AND gate 44. A document detection signal S232 (output of 43) given from the shift register 43 to the AND gate 44 is, for example, as shown in FIG. “0” of “output of 43” shown in FIG. 6 is L level, which means that no document is detected (no document). “1” is at the H level and means document detection (document exists).
[0066]
Since the AND gate 44 is also provided with the line synchronization pulse Lsync, the line synchronization pulse Lsync is applied to the count pulse input terminal CK of the continuous detection counter 45 when the output of 43 is “1”. The continuous detection counter 45 is cleared when the output of 43 is “0” and presets the set value m of the register 46 when switching from “0” to “1”, and arrives from the AND gate 44. The countdown of the pulse Lsync from the set value m is started. Then, when the count data is switched to 0 value due to the countdown, m borrow signals tds indicating completion of counting are generated.
[0067]
The borrow signal tds indicates that the output of the shift register 43, that is, the signal obtained by delaying the original detection signal of the sensor 232 by a predetermined time T is “1” continuously over m periods of the line synchronization pulse Lsync. means. This is the detection of the first timing t5.
[0068]
By this borrow signal tds, the later time counter 78 is initialized to zero value data, and starts to count up Lsync. Then, the count data of the counter 78 representing the number of Lsync pulses generated from the first timing t5 until the carry pulse (t6) is generated is set in the latch 79 by the carry pulse generated by the frequency division counter at t6. . The adder 80 supplies data M = m + g representing the sum of the data m held by the register 46 and the data g held by the latch 79 to the multiplier 47, and the multiplier 47 calculates the product M of M and (Npc / Ns). Output data representing Npc / Ns.
[0069]
If the document detection signal group detected at the first timing t5 is in the S2T1 section of FIG. 6, the document detection signal is delayed by T in the shift register 43, so that the first timing t5 is detected. Is a section of S2T2 in FIG. In the section S2T1 before the section of S2T2, the counter 51 counts up the motor pulses, and the count data of the counter 51 indicating the number Npc of motor pulses generated in the section S2T1 defines the boundary between the sections S2T1 and S2T2. The first counter 41 is held in the first stage of the two-stage latch 51 in response to a carry pulse (second divided pulse) generated by the first counter 41. When the next carry pulse (third divided pulse) is generated, in which the adder 80 outputs data representing M = m + g to the multiplier 47, the count data Npc is shifted to the second stage of the latch 51 and divided. Is provided to a container 52. At this time, the adder 80 outputs data representing M = m + g to the multiplier 47.
[0070]
The register 53 detects the document detected by the shift register 43 during motor driving at a document transfer speed (set constant speed) corresponding to the designated reading magnification during a predetermined time T delay of the document detection signal S232 by the shift register 43. The number of Lsync pulses Ns = 16 generated during a predetermined time T of the signal S232 is stored, and the divider 52 generates data representing Npc / Ns and supplies it to the multiplier 47. Multiplier 47 generates product data representing M × Npc / Ns, which is set in latch 54. The delay 81 captures and holds the borrow pulse tds generated at t5, and outputs it to the latch 54 as a latch instruction signal in synchronization with the next carry pulse (third frequency division pulse).
[0071]
Data M × Npc / Ns held by the latch 54 is supplied to the adder 55. The adder 55 is also given count data Lptn of the start end tracking counter 42, and the adder 55 generates and outputs start end tracking data LPT = M × Npc / Ns + Lptn. The start tracking counter 42 counts up the motor pulse by clearing the count data to 0 value data in response to the carry pulse (1/16) generated by the frequency dividing counter 41 at a fixed period (predetermined time T). However, when the borrow signal tds representing the first timing t5 is generated, the flip-flop 57 is set by this, and the AND gate 56 carries the carry pulse ( 1/16) is stopped, the start-end tracking counter 42 is not cleared even if a carry pulse (third frequency division pulse) is generated next, and the count data Lptn of the start-end tracking counter 42 is determined from the time t3. The start-end tracking data LPT becomes valid when the document detection signal is switched to a level that actually indicates the presence of a document ( Motor pulse generating number equivalent value from the second timing t1), that is, the moving distance.
[0072]
In the timing chart shown in FIG. 6, at the time t1 when the sensor 232 detects the leading edge of the document, the slow-up of the step motor 227 is completed and the set constant speed is reached, so that the predetermined time T (S2T1 period) is reached. Since the count value of the counter 50 is Npc = Np (the number of motor pulses generated during the T period at the set constant speed), the motor pulse number M · Np generated during the M generation times of the Lsync pulse calculated during the S2T2 period / Ns is equal to the number of motor pulses M · Npc / Ns generated during the M generation times of the Lsync pulse in the previous S2T1 period, so this is added to the count data Lptn of the start tracking counter 42 at the t3 base point The starting edge tracking data LPT accurately represents the movement distance of the starting edge of the document from the time t1.
[0073]
However, in the timing chart shown in FIG. 7, since the step motor 227 is slowing up at the time t1 when the sensor 232 detects the leading edge of the document, the count value Npc of the counter 50 for a predetermined time T (S2T1 period) is , Np (the number of motor pulses generated in the T period at the set constant speed). In the illustrated example, there are six. Therefore, the number M.Np/Ns of motor pulses generated during the M generation times of the Lsync pulse calculated in the S2T2 period and the motor pulses generated during the M generation times of the Lsync pulse in the previous S2T1 period. Unlike the number, it is approximately M · Npc / Ns (= 4). The start end tracking data LPT obtained by adding this to the count data Lptn of the start end tracking counter 42 at the t3 base point substantially accurately represents the actual moving distance of the document start end from the time point t1. Here, the expression “substantially accurate” means that M · Npc / Ns averages the motor pulse period during a predetermined period T during slow-up (or slow-down) and divides M (time) by the average period. It is because it becomes the value. Actually, as shown in the S2T1 period in FIG. 7, since the motor pulse period is gradually shortened, that is, the period is not constant (average value), an error corresponding to that is included in the start-end tracking data LPT. . However, the t1 determination error is significantly smaller than when the number of motor pulses generated in the M section of the S2T1 period in FIG. 7 is simply set to the number of generations M · Np / Ns during the set constant speed.
[0074]
Referring again to FIG. 5, the output of the shift register 43 is inverted by the inverter 63 and applied to the AND gate 64 and the counter 65. Accordingly, the counter 65 passes the trailing edge of the original (first timing t5) when the signal obtained by delaying the original detection signal of the sensor 232 by “T” for a predetermined time T is “0” continuously over the m cycles of the line synchronization pulse Lsync. A borrow signal bds is generated. The trailing time counter 78 is initialized to zero value data by the borrow signal bds, and M · Npc / Ns is calculated and set in the latch 74 as in the case of detecting the leading edge of the document.
[0075]
Data M × Npc / Ns held by the latch 74 is applied to the adder 75. The adder 75 is also supplied with count data Lpbn of the rear end tracking counter 62, and the adder 75 generates and outputs rear end tracking data LPB = M × Npc / Ns + Lpbn. The rear end tracking counter 62 clears the count data to 0 value data in response to the carry pulse (1/16) generated by the frequency dividing counter 41 at a fixed period (predetermined time T), and counts the motor pulse. When the borrow signal bds representing the first timing t5 is generated, the flip-flop 59 is set by this, and the AND gate 58 carries the carry pulse to the clear input terminal of the trailing edge tracking counter 62. Since the supply of (1/16) is stopped, the trailing edge tracking counter 62 is not cleared even if the next carry pulse occurs, and the count data Lpbn of the trailing edge tracking counter 62 becomes valid from the time point corresponding to t3. The trailing edge tracking data LPB is obtained when the document detection signal is actually switched to a level indicating that there is no document (second timing t Motor pulse generating number equivalent value from), that is, the moving distance.
[0076]
-Second Example-
FIG. 8 shows a functional configuration of the “original tip / rear end tracking 40d” of the second embodiment used in place of the “original front / rear end tracking 40d” of the first embodiment shown in FIG. In this embodiment, the counter 50 counts motor pulses during one cycle (T / Ns) of the Lsync pulse and outputs it to the shift register 76. The shift register 76 has the same number of stages as the shift stage of the shift register 43, but holds count data and is therefore a multi-bit parallel input / output. The output of the shift register 76 is supplied to an m-1 stage serial input / parallel output (S / P) shift register 77, an adder 83, and an accumulator (accumulator; accumulator) 84.
[0077]
See also the time chart shown in FIG. When the counter 45 generates the borrow signal tds at the first timing t5, the motor pulse count value of each m period before that is obtained from the parallel output terminal of the shift register 77 and from the serial output terminal of the shift register 77. The data is output in parallel to the adder 83, and the adder 83 generates the sum thereof, that is, data representing the number Npm of motor pulse generations in the m section in the S2T1 period shown in FIG. 9, and the accumulator 84 generates the first value ( (Basic value) Then, until the next carry pulse (1/16: second divided pulse in FIG. 9) is generated, the count data output from the shift register 76 is sequentially integrated to the first value in synchronization with the generated Lsync. To do. This integrated value NpM is set in the latch 54 in response to the carry pulse (second divided pulse). The integrated value NpM held in the latch 54 is a value obtained by adding the number of motor pulses generated in the next g section to the number Npm of motor pulses generated in the m section in the S2T1 period, that is, M = m + g section. Is the number of motor pulses generated. The number NpM of motor pulses generated in the M section is added by the adder 55 to the start end tracking data Lptn generated by the start end tracking counter 42 operating in the same manner as in the first embodiment, and the adder 55 outputs the addition data LPT. . This added data LPT is start edge tracking data LPT representing the movement distance (movement position with the sensor as a base point) of the document start edge from the time point t1 when the start edge of the document is detected by the sensor 232.
[0078]
Also in the second embodiment, the passage of the trailing edge of the original is detected by the inverter 63, the AND gate 64, and the counter 65, and the trailing edge tracking data LPB is generated by data processing similar to the generation of the leading edge tracking data.
[0079]
In the second embodiment, as shown in FIG. 9, even if the detection of the document of the sensor 232 is switched from the absence of the document to the presence of the document or vice versa during the slow-up (or slow-down) of the motor ( The number of motor pulses generated between t1) and M sections is accurately calculated, and the start-end tracking accuracy is high.
[0080]
【The invention's effect】
Even if the switching occurs when the motor speed is different from the set constant speed, the switching is performed more than when the timing before the msync pulse of Lsync from the first timing (t5) is set to the timing at which the actual switching has occurred. Timing (t1) is detected accurately.
[Brief description of the drawings]
FIG. 1 is a front view showing the appearance of a copier having a composite function to which a document scanner 10 having a front and rear end tracking function is connected according to a first embodiment of the present invention.
FIG. 2 is an enlarged vertical sectional view showing an outline of a reading mechanism of the document scanner 10 shown in FIG.
3 is a block diagram showing an outline of an image processing system of the copying machine shown in FIG. 1. FIG.
4 is a block diagram showing a configuration of an image reading electric circuit system of the document scanner 10 shown in FIG. 1. FIG.
5 is a block diagram showing a functional configuration of a leading and trailing end tracking function 40d of the motor control unit 40 shown in FIG.
6 is a time chart showing an example of input / output signal timings of the front and rear end tracking function 40d shown in FIG. 4; FIG.
7 is a time chart showing another example of input / output signal timings of the front and rear end tracking function 40d shown in FIG. 4; FIG.
FIG. 8 is a block diagram showing a functional configuration of a front and rear end tracking function 40d according to a second embodiment of the present invention.
9 is a time chart showing an example of input / output signal timings of the front and rear end tracking function 40d shown in FIG. 8;
FIG. 10 is a time chart showing the timing of detection signal check in the detection of the document leading edge according to one conventional mode.
FIG. 11 is a time chart showing the timing of start edge determination in the document start edge detection according to another aspect of the prior art.
[Explanation of symbols]
10: Color document scanner 20: Operation board
30: Automatic document feeder 34: Finisher
34hs: Loading and lowering tray 34ud: Lift platform
34st: Sort tray group
100: Color printer PC: Personal computer
PBX: Switch PN: Communication line
CDIC: Image data interface control
IMAC: Image memory access control
IPP: Image data processor
220, 221: Driving roller
222, 223: driven roller
227: Step motor 228: Imaging device
229: Document guide 231, 232: Document sensor
233: Paper sensor 242: Paper feed roller
243, 244: Conveying roller

Claims (6)

A sensor for detecting the presence or absence of a transfer object at a predetermined position in a transfer path of a transfer mechanism driven by a motor;
Means for detecting a first timing at which the presence / absence detection is switched and the set time is subsequently switched based on the presence / absence detection signal delayed by a predetermined time;
Means for measuring the number of occurrences of one motor pulse per rotation of the motor at a predetermined small angle during the predetermined time; and
Means for calculating the switching timing using the number of occurrences and the first timing measured by the measuring means;
A moving object detection apparatus comprising: A sensor for detecting the presence or absence of a transfer object at a predetermined position in a transfer path of a transfer mechanism driven by a motor;
Means for detecting a first timing at which the presence / absence detection is switched and the set time is subsequently switched based on the presence / absence detection signal delayed by a predetermined time;
Means for counting the number of occurrences of one motor pulse per rotation of the motor at a predetermined small angle during each period of the fixed-cycle pulse;
Means for holding a count value during each said period; and
Means for calculating the switching timing using each count value and the first timing of the holding means;
A moving object detection apparatus comprising: The first timing detection means includes a memory means for separately reading and holding the presence / absence detection signal of the sensor in synchronization with a fixed period pulse, and after a delay of the number of periods of the fixed period pulse corresponding to the predetermined time. 3. The moving object detection device according to claim 1, further comprising: continuous detection means for detecting a continuation corresponding to the set time of the same signal from the presence / absence switching of the presence / absence detection signal of each section of the memory means. The moving object detecting device includes tracking count means for starting measurement of the number of generations of the motor pulses at the start point of the predetermined time, and a period from the first timing to the end point of the predetermined time from the set time. The moving object detection device according to claim 3, further comprising: means for adding the number of motor pulses generated calculated in step 4 to a measurement value of the tracking count means. The detection means includes one that detects an ON change from absence to transfer object and one that detects an OFF change from existence to absence; the calculation means also calculates the ON change timing, and OFF The apparatus for detecting a moving object according to any one of claims 1 to 4, further comprising: calculating a change timing. In a sheet-through type document reading apparatus comprising an image reading optical system, a transfer mechanism for transferring a document in a direction crossing its visual field, and a drive control means for controlling the drive of the transfer mechanism,
6. A document comprising the transported object detection device according to claim 1, wherein the transported object is a document to be scanned, and the transport mechanism feeds the document in a direction crossing the scanning field of view of the image scanning optical system. A transport mechanism, and a motor that drives the transport mechanism is a step motor, and the sensor is a document sensor that detects whether or not there is a document at a predetermined position upstream of the reading field in the transport direction of the document by the transport mechanism. An original reading apparatus, wherein the drive control means controls driving of the transfer mechanism with reference to a second timing calculated by the transferred object detection device.

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