JP2014236275A - Image reader and document sheet transport program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress useless transport operation of a transport section, e.g., a transport roller, even if there is no sheet sensor for detecting a document sheet existing in a transport route, and to suppress useless transport operation of a transport section, e.g., a transport roller, more reliably in a configuration having a sheet sensor.SOLUTION: A scanner 1 has a configuration for performing light reception determination processing for making a first light-emitting part emit light upon start-up, acquiring the light-reception results outputted from a second light-emitting part, and determining whether or not the light-reception results satisfy the sheet existence conditions, and sheet existence time transport processing for making a transport section perform transport operation, by a distance shorter than the overall length of the transport route, and equal to or longer than the distance from the light-receiving position where the second light-emitting part receives light from the first light-emitting part to a discharge position.

Description

  The present invention relates to a technique for discharging a document sheet out of a conveyance path when the power is turned on.

  2. Description of the Related Art Conventionally, there is a facsimile apparatus that discharges a document sheet remaining in a conveyance path when the power is turned on. The facsimile apparatus includes a conveyance roller that conveys a document sheet along a conveyance path, and an edge sensor that detects a document sheet existing in the conveyance path. When the edge sensor detects the document sheet, the facsimile apparatus rotates the transport roller to transport the document sheet to the outside of the transport path.

JP 2004-228611 A

  By the way, some image reading apparatuses such as the above-described facsimile apparatuses do not have a sheet sensor for detecting a document sheet existing in a conveyance path such as an edge sensor. In such an image reading apparatus, it cannot be determined whether or not a document sheet exists in the conveyance path. For this reason, in order to discharge the original sheet in the transport path, it is necessary to rotate the transport roller by the distance over the entire length of the transport path whenever the power is turned on, which imposes a wasteful transport operation. . Further, even in an image reading apparatus having a sheet sensor, for example, the sheet sensor may be erroneously determined to exist, for example, even if there is no document sheet in the conveyance path due to a malfunction or malfunction of the sheet sensor. is there.

  In the present specification, even if there is no sheet sensor for detecting a document sheet existing in the conveyance path, it is possible to prevent a conveyance unit such as a conveyance roller from performing a useless conveyance operation and to have a sheet sensor. Disclosed is a technique that can more reliably suppress the useless transfer operation of a transfer unit such as a transfer roller.

  An image reading apparatus disclosed in this specification includes a conveyance roller provided on a conveyance path extending from an original sheet entry position to an original sheet discharge position, and performs a conveyance operation of rotating the conveyance roller. A first light-emitting unit that emits light to the transport path; a first reading unit that receives light from the transport path and outputs a light reception result; and the first reading unit A second light-emitting unit that is disposed across the transport path and that emits light to the transport path; and a second light-receiving unit that receives light from the transport path and outputs the light reception result 2 reading unit, and a control unit, the control unit, when the image reading device is activated, causes the first light emitting unit to emit light, acquires the light reception result output from the second light receiving unit, The light reception result satisfies the sheet condition. If the light reception determination process for determining whether or not the light reception result satisfies the sheet presence condition, the light is shorter than the total length of the transport path, and the second light receiving unit emits light from the first light emitting unit. And a conveyance process with a sheet that causes the conveyance unit to perform a conveyance operation by a distance that is equal to or greater than the distance from the light receiving position that receives light to the discharge position.

  According to this image reading apparatus, it is possible to detect a document sheet existing in the conveyance path by using the first light emitting unit of the first reading unit and the second light receiving unit of the second reading unit. Accordingly, even if there is no sheet sensor for detecting a document sheet existing in the conveyance path, it is possible to prevent the conveyance unit such as the conveyance roller from performing a wasteful conveyance operation, and in the configuration including the sheet sensor, It is possible to more reliably suppress the useless transfer operation of the transfer unit such as a roller.

  In the image reading apparatus, the control unit causes the first light emitting unit to emit light after the start of the transport operation of the transport unit, acquires the light reception result output by the second light receiving unit, and the light reception result is It has a configuration for executing a post-conveyance determination process that determines whether or not the sheet presence condition is no longer satisfied, and in the conveyance process when the sheet is present, when it is determined that the sheet presence condition is no longer satisfied in the post-conveyance determination process, Furthermore, the structure which makes the said conveyance part perform the said conveyance operation | movement by the distance from the said light reception position to the said discharge position may be sufficient.

  According to this image reading apparatus, it is possible to cause the transport unit to execute a transport operation by an appropriate distance according to the position of the document sheet in the transport path.

The image reading apparatus includes an entry position sensor that detects a document sheet existing at the entry position, and the control unit detects the entry position based on a detection result of the entry position sensor when the image reading apparatus is activated. A first entry determination process for determining whether or not a document sheet exists; a conveyance start process for causing the conveyance unit to start a conveyance operation when it is determined in the entry determination process that a document sheet is present at the entry position;
A second entry determination process for determining whether or not a document sheet no longer exists at the entry position from the detection result of the entry position sensor after the start of the conveying operation;
When it is determined that the original sheet is no longer present at the entry position, a conveyance process at the time of entry in which the conveyance unit performs a conveyance operation by the distance from the entry position to the discharge position is provided. May be.

  According to this image reading apparatus, the document sheet existing at the entry position can be reliably discharged to the discharge position.

  In the image reading apparatus, when the control unit determines that there is no original sheet at the entry position in the entry determination process and determines that the sheet presence condition is not satisfied in the light reception determination process, the light reception It may have a configuration in which a sheet-less conveyance process is executed to cause the conveyance unit to perform a conveyance operation by a distance from a position to the discharge position.

  According to this image reading apparatus, it is possible to discharge a document sheet existing between the light receiving position and the discharge position to the discharge position.

  In the image reading apparatus, the control unit causes the reading unit to store the image before the document sheet reaches the reading position of at least one of the first reading unit and the second reading unit. It is determined whether or not it is determined that the value indicated by the read data has changed between the image acquisition process of starting reading and sequentially acquiring the read data, and the read data, and the value indicated by the read data is A configuration may be provided in which sheet end detection processing is performed in which the position on the read image determined to have changed is the position of the end of the original sheet in the transport direction of the transport unit.

  The present invention can be realized in various modes such as an image reading apparatus, a sheet conveying method, a computer program for realizing the functions of these methods or apparatuses, and a recording medium on which the computer program is recorded.

  According to the invention disclosed in this specification, even if there is no sheet sensor for detecting a document sheet existing in the conveyance path, it is possible to suppress a conveyance unit such as a conveyance roller from performing a useless conveyance operation; Further, in the configuration having the sheet sensor, it is possible to more reliably suppress the useless conveyance operation of the conveyance unit such as the conveyance roller.

1 is a schematic configuration diagram of a scanner according to an embodiment. Enlarged view showing simplified reading unit and counter member Block diagram showing the electrical configuration of the scanner Flowchart showing document discharge processing Flow chart showing reading control processing

  <One Embodiment>

  A scanner 1 according to an embodiment will be described with reference to FIGS. The scanner 1 is an example of an image reading device. In the following description, the left side of FIG. 1 is the front side (F) of the scanner 1, the front side of the paper is the right side (R) of the scanner 1, and the upper side of the paper is the upper side (U) of the scanner 1.

(Mechanical structure of the scanner)
As shown in FIG. 1, the scanner 1 includes a case 2, a document tray 3, a discharge tray 4, an automatic document feeder (hereinafter referred to as “ADF”) 5, a first reading unit 6, a second reading unit 7, and a first reading unit. A counter member 8, a second counter member 9, a front sensor 10, and the like are provided.

  The case 2 has a box shape as a whole, and an entrance 2A is formed on one side thereof, that is, the rear side in FIG. The document tray 3 is provided at the entrance 2A, and one or a plurality of document sheets M can be arranged in a stacked manner on the document tray 3. The original sheet M is not limited to paper, but may be made of plastic. A front sensor 10 is provided on the front end side of the document tray 3. The front sensor 10 is a document presence / absence sensor that detects the presence / absence of the document sheet M on the document tray 3 at a detection position set on the front end side of the document tray 3, and transmits the detection result to the control unit 100. The front sensor 10 is an example of an entry position sensor. Hereinafter, the detection position of the front sensor 10 is referred to as an entry position XS of the document sheet M.

  A discharge port 2 </ b> B is formed on the other surface different from the one surface of the case 2, that is, the upper surface in FIG. 1. The discharge tray 4 is provided behind the discharge port 2B, and one or a plurality of document sheets M discharged from the case 2 can be arranged in a stack on the discharge tray 4. Hereinafter, the position of the discharge port 2B, in other words, the position of the front end of the discharge tray 4 is referred to as a discharge position XE of the document sheet M. Further, a path extending from the entry position XS to the discharge position XE, that is, a path indicated by a dotted arrow in FIG.

  The ADF 5 is an example of a transport unit, separates a plurality of document sheets M on the document tray 3 one by one, transports them along the transport path R, and sequentially discharges them to the discharge tray 4. Specifically, the ADF 5 includes a separation roller 51, a separation pad 52, a plurality of conveyance rollers 53, a plurality of driven rollers 54 that are driven in pressure contact with the respective conveyance rollers 53, and a guide unit (not shown) for guiding the document sheet M. Etc., and a conveying operation is performed in which these conveying rollers 53 and the like rotate in a direction (indicated by a dotted arrow in FIG. 1) in which the original sheet M is conveyed from the entry position XS toward the discharge position XE.

  The separation roller 51 and the conveyance roller 53 are rotationally driven by a stepping motor 55 described later. As a result, the separation roller 51 and the separation pad 52 separate a plurality of document sheets M on the document tray 3 one by one and send them out into the conveyance path R. The conveyance roller 53 conveys the separated document sheet M in a U-shape along the conveyance path R, and discharges it onto the discharge tray 4. The ADF 5 has a so-called one-way clutch mechanism, and continuously executes a continuous transfer operation after receiving a transfer start command from the control unit 100 until receiving a transfer stop command. In this continuous conveyance operation, a plurality of document sheets M on the document tray 3 are separated one by one, and are continuously conveyed along the conveyance path R with an interval between the document sheets M, and are discharged to the discharge tray 4. This is a transport operation that sequentially discharges.

  The first reading unit 6 and the second reading unit 7 are arranged across the conveyance path R, and read images on different surfaces of the original sheet M at different reading positions on the conveyance path R, respectively. Specifically, the first reading unit 6 reads an image on one side of the original sheet M, in other words, on the upper surface of the original sheet M placed on the original tray 3 at the first reading position X1. On the other hand, the second reading unit 7 is located on the other side of the document sheet M, in other words, on the document tray 3, at the second reading position X2 downstream of the first reading position X1 on the transport path R. The image on the lower surface of the sheet M is read.

  The first reading unit 6 is a reading device having a CIS (Contact Image Sensor). The first reading unit 6 is arranged on the lower side of the conveyance path R, and sequentially reads line-shaped images along the main scanning direction at the first reading position X1 on the conveyance path R, and the pixel rows of the respective lines. Data (an example of read data, hereinafter referred to as line data) is transmitted to the control unit 100. The main scanning direction is a direction orthogonal to the conveying direction by the ADF 5, and is the left-right direction in FIG.

  The control unit 100 performs AD conversion on the transmitted line data by an AD conversion unit (not shown). The specific configurations and arrangement relationships of the first reading unit 6 and the first facing member 8 will be described later. The first reading unit 6 is not limited to the CIS, and may be configured to have, for example, a CCD (Charge Coupled Drive Image Sensor).

  The first facing member 8 is an example of a facing member, is positioned above the transport path R, and is disposed to face the first reading unit 6 via the transport path R. Of the first facing member 8, the facing surface 8A facing the first reading unit 6 is, for example, white. Note that the facing surface 8A is not necessarily white, and may be another color such as gray.

  The second reading unit 7 is a reading device having a CIS. The second reading unit 7 is located above the transport path R, and sequentially reads line-shaped images along the main scanning direction at the second read position X2 on the transport path R to control each line data. To the unit 100. The control unit 100 performs AD conversion on the transmitted line data by an AD conversion unit (not shown). The specific configurations and arrangement relationships of the second reading unit 7 and the second opposing member 9 will be described later. Further, the second reading unit 7 is not limited to the CIS, and may be configured to have a CCD, for example.

  The second facing member 9 is an example of a facing member, is positioned below the transport path R, and is disposed to face the second reading unit 7 via the transport path R. Of the second facing member 9, the facing surface 9A facing the second reading unit 7 is, for example, white. Note that the facing surface 9A is not necessarily white, and may be another color such as gray.

(Configuration of reading unit and counter member)
FIG. 2 schematically shows the configuration of the reading units 6 and 7 and the opposing members 8 and 9. In the drawing, the optical paths of the light beams LR, LG, and LB of each color are schematically illustrated so as to be distinguished, and the ranges of the reading positions X1 and X2 that are the irradiation ranges thereof are also illustrated. Further, FIG. 6 shows a state in which the light beams LR, LG, LB of each color are reflected by the facing surfaces 8A, 9A of the facing members 8, 9.

  The first reading unit 6 includes a first light emitting unit 61 and a first light receiving unit 62. Specifically, the first light emitting unit 61 includes an LED substrate 61A and a light guide 61B, and emits light toward the first reading position X1 on the transport path R. The LED substrate 61A has an R color LED (light emitting diode) 63R that emits red (R) light LR, a G color LED 63G that emits green (G) light LG, and a B that emits blue (B) light LB. The color LEDs 63B are arranged at positions shifted from each other along the front-rear direction, in other words, along the transport direction of the transport path R. The light guide 61B is an optical member that guides the light beams LR, LG, and LB from the LEDs 63R, 63G, and 63B to the first reading position X1.

  The first light receiving unit 62 includes a light receiving lens 62A and a light receiving substrate 62B, and receives reflected light from the transport path R. The light receiving lens 62A is an optical member that guides light from the first reading position X1 side to the light receiving substrate 62B. The light receiving substrate 62B has a configuration in which a plurality of light receiving elements 64 are arranged side by side along the main scanning direction. The emission directions of the light beams LR, LG, and LB of each color are inclined with respect to the facing direction (vertical direction) between the first light receiving unit 62 and the facing surface 8A of the first facing member 8.

  The second reading unit 7 includes a second light emitting unit 71 and a second light receiving unit 72. The second light emitting unit 71 includes an LED substrate 71A and a light guide 71B, and emits light toward the second reading position X2 on the transport path R. The LED substrate 71A and the light guide 71B, and the LED substrate 61A and the light guide 61B are different in arrangement relation, but the configuration is the same. On the LED substrate 71A, an R color LED 73R that emits the light LR, a G color LED 73G that emits the light LG, and a B color LED 73B that emits the light LB are arranged at positions shifted from each other along the front-rear direction.

  The second light receiving unit 72 includes a light receiving lens 72A and a light receiving substrate 72B, and receives reflected light from the transport path R. The light receiving lens 72A and the light receiving substrate 72B, and the light receiving lens 62A and the light receiving substrate 62B are different in arrangement relation, but the configuration is the same. The light receiving substrate 72B has a configuration in which a plurality of light receiving elements 74 are arranged side by side along the main scanning direction.

  When the original sheet M does not exist at the reading positions X1 and X2, the second light receiving unit 72 of the second reading unit 7 performs the first light emission of the first reading unit 6 as indicated by a two-dot chain line arrow in FIG. It is arranged at a position where it can receive the diffused light of the light beams LR, LG, LB emitted from the section 61. Hereinafter, this diffused light is referred to as first diffused light L1. When the original sheet M is not present at the reading positions X1 and X2, the first light receiving unit 62 of the first reading unit 6 is connected to the second light emitting unit of the second reading unit 7 as indicated by a two-dot chain line in FIG. It is arranged at a position where it can receive diffused light of light LR, LG, LB emitted by 71. Hereinafter, this diffused light is referred to as second diffused light L2. Further, a position on the transport path R through which the first diffused light L1 or the second diffused light L2 passes is referred to as a light receiving position XU.

  With the above configuration, the scanner 1 can execute a double-sided reading operation and a single-sided reading operation. The duplex reading is a reading operation in which the first reading unit 6 and the second reading unit 7 respectively read images on both sides of the document sheet M. The single-sided reading is a reading operation in which only one of the first reading unit 6 and the second reading unit 7 reads only an image on one side of the original sheet M.

  The first reading unit 6 and the second reading unit 7 can selectively execute a color reading operation and a monochrome reading operation. In the color reading operation, for example, the LEDs 63R, 63G, and 63B of the first light emitting unit 61 are caused to emit light in a time-sharing manner, and the light beams LR, LG, and LB reflected at the first reading position X1 are received by the first light receiving unit 62. The RGB color line data is sequentially read out as a set of line data. In the monochrome reading operation, for example, any one of the LEDs 63R, 63G, and 63B (for example, LED 63G) of the first light emitting unit 61 is caused to emit light, and the light of each color reflected at the first reading position X1 is received by the first light receiving unit 62. The reading operation sequentially outputs the line data of one color.

(Electrical configuration of the scanner)
As shown in FIG. 3, the scanner 1 includes a control unit 100, and the control unit 100 includes an ADF 5, a first reading unit 6, a second reading unit 7, a front sensor 10, a power switch 110, an operation unit 120, And the display part 130 is connected so that data communication is possible.

  The control unit 100 includes a central processing unit (hereinafter referred to as CPU) 101, a ROM 102, a RAM 103, and an image processing circuit 104. The ROM 102 stores a program (an example of a document sheet conveyance program) for executing document discharge processing and reading control processing described later, and a program for executing various operations of the scanner 1. The CPU 101 controls each unit of the scanner 1 according to a program read from the ROM 102. Note that the ROM 102 and the RAM 103 are examples of a storage unit. In addition to the ROM 102 and the RAM 103, the storage medium for storing the various programs may be a non-volatile memory such as a CD-ROM, a hard disk device, or a flash memory.

  The image processing circuit 104 is a hardware circuit dedicated to image processing, for example. Specifically, the image processing circuit 104 performs edge detection processing or the like on the line data of each color subjected to the AD conversion, and generates edge detection edge pixel data. Specifically, the image processing circuit 104 includes a color conversion unit 104A and an edge detection unit 104B. The color conversion unit 104A performs color conversion processing such as YCbCr conversion and YIQ conversion on the line data of each color, and generates post-color conversion data indicating a luminance value and a color difference value for each color.

  The edge detection unit 104B performs an edge detection process for detecting edge pixels from the image corresponding to the color-converted data with respect to the generated color-converted data. In this edge detection process, various known edge detection methods can be used. Hereinafter, the edge detection unit 104B uses an edge detection method using a differential filter. Specifically, the edge detection unit 104B applies the difference filter coefficient to the color-converted data to detect the edge strength of each pixel, and the edge strength is not less than a predetermined edge detection threshold value. For example, the pixel is an edge pixel.

  The ADF 5 includes a stepping motor 55 and a motor driver 56, and executes a conveying operation for rotationally driving the rollers 51 and 53 described above. For example, when a clock signal is input from the CPU 101, the motor driver 56 updates the signal for each pulse of the clock signal, and supplies a current to the coil based on the signal, thereby making the stepping motor 55 one step ( Rotate by a predetermined angle). As a result, the rollers 51 and 53 are driven to rotate in accordance with the rotation of the stepping motor 55.

  The power switch 110 can be turned on and off by the user. When the power switch 110 is turned on, power is supplied to each unit in the scanner 1 from an external power source, for example. The power switch 110 may be a hard switch or a soft switch. The operation unit 120 has a plurality of buttons, and allows the user to perform various input operations such as selection of a double-sided reading mode and a single-sided reading mode. The display unit 130 includes a liquid crystal display, a lamp, and the like, and can display various setting screens and operation states of the apparatus.

(Original discharge processing)
For example, when the user turns off the power switch 110 to turn it on again, or the power switch 110 is turned on and the user performs an operation for restarting the scanner 1 with the operation unit 120, the control unit 100 The document discharge process shown in FIG. 4 is executed. For example, the control unit 100 determines that the scanner 1 has been activated when the energization of the CPU 101 is started.

  The document discharge process is a process for automatically discharging the document sheet M mainly remaining in the transport path R to the discharge tray 4 on condition that the scanner 1 is activated. Further, in the document discharge process, the first reading unit 6 and the second reading unit 7 are used instead of the sheet sensor to determine whether or not the document sheet M exists in the conveyance path R, and the document sheet M Is shorter than the entire length of the transport path R, and is a distance that is equal to or greater than the distance from the light receiving position XU where the document sheet M is detected by the first reading unit 6 and the second reading unit 7 to the discharge position XE. This is a process for causing the ADF 5 to perform the transport operation by the amount. By executing the document discharge process, it is possible to prevent the reading control process described later from being started while the document sheet M exists in the transport path R.

  Specifically, the CPU 101 determines whether a document sheet M exists on the document tray 3 from the detection result of the front sensor 10 (S1). The process of S1 is an example of a first entry determination process.

(1) When Document Sheet Does Not Exist on Document Tray When CPU 101 determines that document sheet M does not exist on document tray 3 (S1: NO), CPU 101 causes first light emitting unit 61 to emit light and second light receiving unit 72. The line data output from the second light receiving unit 72 is sequentially acquired (S2). Then, the CPU 101 determines from the line data whether the light reception result of the second light receiving unit 72 satisfies the sheet presence condition (S3). The processing of S2 and S3 is an example of light reception determination processing. At this time, it is preferable that the CPU 101 does not emit the second light emitting unit 71 and does not acquire the line data output by the first light receiving unit 62.

  As shown in FIG. 2, if there is no original sheet at the light receiving position XU, the second light receiving unit 72 receives the first diffused light L1 emitted from the first light emitting unit 61. On the other hand, if the original sheet M exists at the light receiving position XU, the second light receiving unit 72 hardly receives the first diffused light L1. Therefore, it can be determined from the light reception result of the second light receiving unit 72 whether or not the document sheet M exists at the light receiving position XU, in other words, in the transport path R.

  Examples of the sheet presence condition include that the amount of light received by the second light receiving unit 72 is less than the sheet determination threshold, or within the sheet determination range. For example, the sheet determination threshold value is the amount of light received by the second light receiving unit 72 when the document sheet M exists at the light receiving position XU and the amount of light received by the second light receiving unit 72 when the document sheet M does not exist at the light receiving position XU. A value between is preferred. The amount of light received by the second light receiving unit 72 may be, for example, an average value, a maximum value, or an intermediate value between the maximum value and the minimum value of each pixel from line data.

  Here, a configuration is also conceivable in which it is determined whether or not the document sheet M exists in the transport path R by using only the second reading unit 7 without using the first reading unit 6. Specifically, the control unit 100 causes the second light emitting unit 71 to emit light and causes the second light receiving unit 72 to receive the reflected light from the second reading position X2. However, in this configuration, the difference in the amount of light received by the second light receiving unit 72 between when the document sheet M is present at the second reading position X2 and when the document sheet M is not present is relatively small, and thus the detection accuracy of the document sheet M is low. This is because the reflection characteristic of the facing surface 9A of the second facing member 9 is relatively close to the reflection characteristic of the document sheet M in order to suppress the influence on the reading of the second reading unit 7. For this reason, in the tip detection processing described later, the control unit 100 executes complicated processing such as edge extraction processing by the edge detection unit 104B and the like.

  On the other hand, in the configuration of the present embodiment, the difference in received light amount of the second light receiving unit 72 between the presence and absence of the original sheet M at the light receiving position XU is relatively large. This is because the first diffused light L1 from the first light emitting unit 61 is blocked by the original sheet M, and the amount of light received by the second light receiving unit 72 is greatly attenuated. Therefore, in the document discharge process, the control unit 100 can determine whether or not the document sheet M exists from the light reception result of the second light receiving unit 72, that is, the amount of received light, without executing the edge extraction process or the like. it can.

(1-1) When the light reception result satisfies the sheet presence condition In S3, when the CPU 101 determines that the light reception result of the second light receiving unit 72 satisfies the sheet presence condition (S3: YES), from the total length of the conveyance path R The ADF 5 is caused to perform a transport operation by a distance that is shorter than the distance from the light receiving position XU to the discharge position XE (S4 to S6). This process is an example of a sheet conveyance process.

  Specifically, the CPU 101 first causes the ADF 5 to start a transport operation (S4), and then causes the first light emitting unit 61 to emit light, acquires the light receiving result output by the second light receiving unit 72, and the light receiving result is It is determined whether or not the sheet presence condition is satisfied (S5). The process in S5 is an example of a post-conveyance determination process, and the sheet presence condition is the same as that in S3.

  When the CPU 101 determines that the light reception result satisfies the sheet presence condition (S5: NO), the document sheet M continues to exist at the light reception position XU, and thus the process of S5 is repeated. Then, when the trailing edge of the document sheet M being conveyed exits the light receiving position XU, the CPU 101 determines that the light receiving result no longer satisfies the sheet presence condition (S5: YES). Then, the CPU 101 further stops the conveying operation after the ADF 5 continues the conveying operation by the distance from the light receiving position XU to the discharging position XE (S6), and ends the original document discharging process.

  For example, the CPU 101 counts the time from the time when it is determined that the sheet presence condition is no longer satisfied or the number of steps to the motor driver 56, and the count value becomes a value corresponding to the distance from the light receiving position XU to the discharge position XE. When it reaches, the ADF 5 is stopped. In short, the ADF 5 performs the transport operation until the trailing edge of the document sheet M is discharged from the light receiving position XU to the discharge position XE.

  Thereby, when the document sheet M exists at the light receiving position XU, the ADF 5 can be transported by a minimum distance necessary for discharging the entire document sheet M onto the discharge tray 4.

(1-2) When the light reception result does not satisfy the sheet presence condition Here, in the scanner 1, the distance between the advance position XS and the light reception position XU is shorter than the length in the conveyance direction of the document sheet M. And Accordingly, the determination that the document sheet M does not exist at the entry position XS or the light receiving position XU means that the document sheet M does not exist at least between the entry position XS and the light receiving position XU. Conversely, there is a possibility that the original sheet M exists between the light receiving position XU and the discharge position XE. However, the scanner 1 cannot determine whether or not the original sheet M exists between them.

  Therefore, when the CPU 101 determines in S3 that the light reception result does not satisfy the sheet presence condition (S3: NO), the CPU 101 performs the transport operation to the ADF 5 by the distance from the light reception position XU to the discharge position XE as in S6. After continuing, the conveying operation is stopped (S7), and the original discharge process is terminated. The process of S7 is an example of a sheet-less conveyance process. Thereby, the document sheet M that may exist between the entry position XS and the light receiving position XU can be reliably discharged to the discharge tray 4.

(2) When there is a document sheet on the document tray When the CPU 101 determines in S1 that the document sheet M exists on the document tray 3 (S1: YES), the CPU 101 causes the ADF 5 to start a transport operation (S8). Thereafter, the CPU 101 determines from the detection result of the front sensor 10 whether or not the original sheet M no longer exists on the original tray 3 (S9). The process of S9 is an example of a second entry determination process.

  Until the trailing edge of the document sheet M on the document tray 3 leaves the entry position XS, the CPU 101 waits (S9: NO), and when the trailing edge of the document sheet M on the document tray 3 leaves the entry position XS. The CPU 101 determines that the document sheet M no longer exists on the document tray 3 (S9: YES). Then, the CPU 101 further stops the transport operation after the ADF 5 continues the transport operation for the distance from the entry position XS to the discharge position XE, in other words, the entire length of the transport path R (S10), and discharges the original document. The process ends.

  For example, the CPU 101 counts the time from when it is determined that the document sheet M no longer exists on the document tray 3 or the number of steps to the motor driver 56, and the count value is from the entry position XS to the discharge position XE. When the value corresponding to the distance is reached, the ADF 5 is stopped. The process of S10 is an example of the on-entry conveyance process. Thereby, the document sheet M present at the entry position XS can be reliably discharged from the discharge position XE.

  If the CPU 101 determines that the document sheet M is present on the document tray 3 (S1: YES), the CPU 101 prohibits the light reception determination processing of S2 and S3 without executing it, and causes the ADF 5 to start the transport operation. Thereby, it is possible to prevent the light reception determination process from being performed wastefully.

(Reading control processing)
When the user gives a reading instruction using the operation unit 120, the control unit 100 performs reading control processing shown in FIG. 5 on the condition that a document sheet is present on the document tray 3 based on the detection result of the front sensor 10. Execute. Hereinafter, a case where the one-side reading operation by the first reading unit 6 is executed will be described as an example.

  The CPU 101 causes the first reading unit 6 to perform a monochrome reading operation on the facing surface 8A of the first facing member 8 (S21). As a result, the image processing circuit 104 outputs edge pixel data of one main scanning line using line data of one color (for example, B color) output from the first reading unit 6, and the CPU 101 outputs the edge pixel data. (S22), and using the edge pixel data, the number of edge pixels for one color is calculated and stored in the RAM 103 as the reference pixel number V (S23). The facing surface 8A is assumed to have a rougher surface than the original sheet M.

  Next, the CPU 101 causes the ADF 5 to perform a conveyance operation (S24), and causes the monochrome reading operation to read an image for one main scanning line (S25). The process of S25 is an example of an image acquisition process. As a result, the image processing circuit 104 outputs edge pixel data of one main scanning line using the line data of one color output from the first reading unit 6. The CPU 101 calculates the number of edge pixels for one color using the edge pixel data, and determines whether the edge pixel is smaller than the reference pixel number V (S26).

  When the CPU 101 determines that the edge pixel is not smaller than the reference pixel number V (S26: NO), the CPU 101 returns to S25 because the leading edge of the document sheet M has not yet reached the first reading position X1. On the other hand, when the CPU 101 determines that the edge pixel is smaller than the reference pixel number V (S26: YES), the leading edge of the document sheet M has reached the first reading position X1. That is, the CPU 101 has detected the position of the leading edge of the document sheet M at the first reading position X1. The process of S26 is an example of a sheet edge detection process.

  When the CPU 101 detects the position of the leading edge of the document sheet M, it starts document reading for reading an image on the document sheet M (S27). Then, in parallel with the document reading, the CPU 101 causes the first reading unit 6 to read an image for one main scanning line by a color reading operation (S28). Accordingly, the image processing circuit 104 outputs edge pixel data of one main scanning line using the three color line data output from the first reading unit 6. The CPU 101 calculates the number of edge pixels for each color using the edge pixel data, and determines whether or not the edge pixel is smaller than the reference pixel number V (S29).

  If the CPU 101 determines that the edge pixel is smaller than the reference pixel number V even for one color (S29: YES), since the trailing edge of the original sheet M has not reached the first reading position X1, the process returns to S28. . On the other hand, if the CPU 101 determines that the edge pixel is not smaller than the reference pixel number V for all three colors (S29: NO), the trailing edge of the document sheet M has reached the first reading position X1. That is, the CPU 101 detects the position of the trailing edge of the document sheet M at the first reading position X1. The process of S29 is an example of a sheet edge detection process.

  After detecting the position of the trailing edge of the original sheet M, the CPU 101 ends the reading operation of the first reading unit 6, stops the original reading (S30), causes the ADF 5 to stop the conveying operation (S31), and performs the main reading. The control process ends.

(Effect of this embodiment)
According to the present embodiment, the document sheet M present in the transport path R is detected using the first light emitting unit 61 of the first reading unit 6 and the second light receiving unit 72 of the second reading unit 7. be able to. Thereby, even if there is no sheet sensor for detecting the original sheet M present in the conveyance path R, it is possible to suppress the ADF 5 from performing a wasteful conveyance operation, and in the configuration having the sheet sensor, the ADF 5 is useless. It is possible to more reliably suppress the carrying operation.

<Other embodiments>
The technology disclosed in the present specification is not limited to the embodiments described with reference to the above description and drawings, and includes, for example, the following various aspects.

  In the embodiment described above, the scanner 1 having only the scanner function is given as an example of the image reading apparatus. However, the present invention is not limited to this, and the image reading apparatus may be a multifunction machine capable of executing a plurality of functions such as a copy function, a facsimile machine, or the like in addition to the scan function. Further, the image reading apparatus may be configured such that the document tray is disposed above the discharge tray.

  The scanner 1 may be configured such that the second reading unit 7 and the second reading position X2 are located on the upstream side of the transport path R from the first reading unit 6 and the first reading position X1.

  In the above embodiment, the first light receiving unit 62 of the first reading unit 6 has the light beams LR and LG emitted from the second light emitting unit 71 of the second reading unit 7 when the document sheet M is not present at the reading positions X1 and X2. , LB may be arranged at a position where light cannot be received. In the above embodiment, the second light receiving unit 72 of the second reading unit 7 emits the light LR emitted from the first light emitting unit 61 of the first reading unit 6 when the document sheet M does not exist at the reading positions X1 and X2. , LG and LB are arranged at positions where light cannot be received.

  In the above embodiment, the control unit 100 is configured to execute the document discharge processing and the like by the CPU 101 and the hardware circuit such as the image processing circuit 104. However, the present invention is not limited to this, and the control unit 100 is configured to execute document discharge processing or the like by only one or a plurality of CPUs, or to execute document discharge processing or the like only by a hardware circuit such as ASIC (Application Specific Integrated Circuit). But you can. For example, a part or all of the processing executed by the image processing circuit 104 may be executed by a CPU and a memory.

  The control unit 100 determines whether or not it is determined that the power switch 110 is turned on and the power saving mode is shifted to the normal mode in which power that can execute the reading control process is supplied, and the mode is shifted to the normal mode. If it is determined that the document is discharged, the document discharge process may be executed. The scanner 1 may not have the power switch 110 and may be configured such that power is supplied when a power cord (not shown) is connected to a commercial power source. Even in this configuration, the control unit 100 can determine that the scanner 1 has been activated, for example, when the energization of the CPU 101 is started.

  The control unit 100 causes the second light emitting unit 71 to emit light in S2 and S3, acquires the light reception result output by the first light receiving unit 62, and determines whether the light reception result satisfies the sheet presence condition. Good.

  In S <b> 2 of FIG. 4, the control unit 100 may cause all of the R color LED 63 </ b> R, the G color LED 63 </ b> G, and the B color LED 63 </ b> B included in the first light emitting unit 61 to emit light or two of them. And only one may emit light. Further, the control unit 100 may cause the second light emitting unit 71 to emit light in addition to the first light emitting unit 61 in S2.

  The CPU 101 may acquire the image density instead of the number of edge pixels, and the position on the read image at which it is determined that the image density has changed may be the end position of the document sheet M.

  1: scanner 5: ADF 6: first reading unit 7: second reading unit 8: first counter member 9: second counter member 53: transport roller 61: first light emitting unit 61 62: first light receiving unit M: document Sheet R: transport path X1: first reading position X2: second reading position XS: entry position XE: discharge position

Claims (6)

An image reading device,
A transport unit that includes a transport roller provided in a transport path extending from an entry position of the document sheet to a discharge position of the document sheet, and that performs a transport operation that rotates the transport roller;
A first light-emitting unit that emits light to the conveyance path; and a first reading unit that has a first light-receiving unit that receives light from the conveyance path and outputs the light reception result;
A second light-emitting unit that is disposed across the conveyance path with respect to the first reading unit, emits light to the conveyance path, and a second light that receives light from the conveyance path and outputs the light reception result A second reading unit having a light receiving unit;
A control unit,
The controller is
When the image reading device is activated, the first light emitting unit emits light, the light receiving result output by the second light receiving unit is acquired, and the light receiving determination process determines whether the light receiving result satisfies a sheet presence condition. When,
When it is determined that the light reception result satisfies the sheet presence condition, the length is shorter than the entire length of the conveyance path, and the second light receiving unit receives light from the first light emitting unit to the discharge position. An image reading apparatus having a configuration for performing a sheet-in-conveyance process that causes the conveyance unit to perform a conveyance operation by a distance equal to or greater than a distance. The image reading apparatus according to claim 1,
The controller is
After the transport operation of the transport unit is started, the first light emitting unit is caused to emit light, the light reception result output by the second light receiving unit is acquired, and it is determined whether or not the light reception result does not satisfy the sheet presence condition. Having a configuration for executing post-conveyance determination processing,
In the conveyance process when there is a sheet, when it is determined in the post-conveyance determination process that the sheet presence condition is no longer satisfied, the conveyance operation is further performed on the conveyance unit by the distance from the light receiving position to the discharge position. An image reading apparatus that is configured to perform the above-described operation. The image reading apparatus according to claim 1, wherein:
An entry position sensor for detecting a document sheet present at the entry position;
The controller is
A first entry determination process for determining whether a document sheet exists at the entry position from the detection result of the entry position sensor when the image reading apparatus is activated;
When it is determined in the entry determination process that a document sheet exists at the entry position, a conveyance start process for causing the conveyance unit to start a conveyance operation;
A second entry determination process for determining whether or not a document sheet no longer exists at the entry position from the detection result of the entry position sensor after the start of the conveying operation;
When it is determined that the original sheet is no longer present at the entry position, the entry portion has a configuration for performing an entry-time conveyance process that causes the conveyance unit to perform a conveyance operation by a distance from the entry position to the discharge position. Image reading device. The image reading apparatus according to claim 3,
The controller is
If it is determined in the entry determination process that there is no document sheet at the entry position, and it is determined in the light reception determination process that the sheet presence condition is not satisfied, only the distance from the light reception position to the discharge position, An image reading apparatus having a configuration for performing a sheet-less conveyance process that causes the conveyance unit to perform a conveyance operation. The image reading apparatus according to any one of claims 1 to 4,
The controller is
Before the transport unit causes the original sheet to reach the reading position of at least one of the first reading unit and the second reading unit, the reading unit starts reading the image, and sequentially acquires the read data. Image acquisition processing to
It is determined whether or not the value indicated by the read data has changed between the read data, and the position on the read image that has been determined that the value indicated by the read data has changed is transported by the transport unit. An image reading apparatus having a configuration for executing sheet edge detection processing for setting a position of an edge of an original sheet with respect to a direction. A transport unit that includes a transport roller provided in a transport path extending from an entry position of the document sheet to a discharge position of the document sheet, and that performs a transport operation that rotates the transport roller;
A first light-emitting unit that emits light to the conveyance path; and a first reading unit that has a first light-receiving unit that receives light from the conveyance path and outputs the light reception result;
A second light-emitting unit that is disposed across the conveyance path with respect to the first reading unit, emits light to the conveyance path, and a second light that receives light from the conveyance path and outputs the light reception result An image reading apparatus including a second reading unit having a light receiving unit;
When the image reading device is activated, the first light emitting unit emits light, the light receiving result output by the second light receiving unit is acquired, and the light receiving determination process determines whether the light receiving result satisfies a sheet presence condition. When,
When it is determined that the light reception result satisfies the sheet presence condition, the length is shorter than the entire length of the conveyance path, and the second light receiving unit receives light from the first light emitting unit to the discharge position. A document sheet conveyance program for executing a sheet-in-the-sheet conveyance process that causes the conveyance unit to perform a conveyance operation by a distance that is equal to or greater than the distance.

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