Image reading device

Abstract

In an image reading device having multiple line sensors arranged in a parallel direction in the main scanning direction intersecting the document transport direction, document jamming is suppressed. [Solution] An image reading device comprising a plurality of line sensors extending in a main scanning direction perpendicular to the document transport direction and arranged in a staggered pattern along the main scanning direction, wherein the device generates an image of a document by stitching together images read by the plurality of line sensors while transporting the document in the transport direction to the plurality of line sensors, wherein the end line sensors located at the ends in the main scanning direction are positioned upstream in the transport direction from the line sensors adjacent to the end line sensors, the end line sensors have an end region outside the effective area through which the document passes, and the device has a detection means for detecting the transport state of the document based on a first image which is an image read by the end line sensor in the end region while the document is being transported by the transport means.

Description

Technical Field

[0001] The present invention relates to an image reading apparatus having a line sensor.

Background Art

[0002] In a sheet feed type image reading apparatus, jams may occur when the document is skewed due to document conveyance and contacts the end of the apparatus. In contrast, there is a technique for suppressing the occurrence of jams by providing a jam detection sensor at the end of the apparatus and detecting the document with this sensor.

[0003] Patent Document 1 describes a technique for using a side region where the document does not pass through among the reading regions of line sensors arranged in an image reading apparatus for jam detection. In this technique, the output of the side region of the line sensor in the state where there is no document is compared with the output of the side region of the line sensor when the document is being conveyed, and it is determined whether a jam has occurred. By using the side region of the line sensor, it becomes possible to detect a jam without separately providing a jam detection sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is an image reading apparatus having a plurality of line sensors arranged in a staggered manner in the main scanning direction intersecting the document conveyance direction, and generating a read image by connecting images read by the plurality of line sensors. According to an image reading apparatus having such a configuration, a large - size document can be read.

[0006] The present invention aims to provide a technique for suppressing document jams in an image reading device having a plurality of line sensors arranged in a staggered pattern in the main scanning direction intersecting the document transport direction. [Means for solving the problem]

[0007] This invention relates to a transport means for transporting a document, A plurality of line sensors extending in a main scanning direction perpendicular to the document transport direction, wherein the plurality of line sensors are arranged in a staggered pattern along the main scanning direction, An image reading device comprising, which generates an image of a document by concatenating images read by a plurality of line sensors while transporting the document to a plurality of line sensors in the transport direction, Of the plurality of line sensors, the end line sensor located at the end in the main scanning direction is positioned upstream in the transport direction from the line sensor adjacent to the end line sensor. The end line sensor has an end region outside the effective region through which the document passes. The image reading device is characterized by having a detection means that detects the transport state of a document based on a first image, which is an image read by the end line sensor in the end region while the document is being transported by the transport means. [Effects of the Invention]

[0008] According to the present invention, multiple devices are arranged in a staggered pattern in the main scanning direction intersecting the document transport direction. In an image reading device with multiple line sensors, it is possible to suppress document jamming. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the overall configuration of the image reading device in Example 1. [Figure 2] This is a block diagram showing the hardware configuration of the image reading device in Example 1. [Figure 3]This is a flowchart of the skew detection process of the image reading device in Example 1. [Figure 4] This figure shows the data acquisition process for detecting skew in Example 1. [Figure 5] This is a flowchart illustrating the data acquisition process for detecting skew in Example 1. [Figure 6] This figure shows the data acquisition process for detecting skewness in the image reading device of Example 2. [Figure 7] This is a flowchart of the data acquisition process for detecting skew in the image reading device of Example 2. [Modes for carrying out the invention]

[0010] The following describes exemplary embodiments for carrying out the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments may be appropriately changed depending on the configuration and various conditions of the apparatus to which the present invention is applied, and the scope of the present invention is not intended to be limited to the following embodiments.

[0011] (Example 1) Example 1 describes a method for detecting the skewness of a document using line sensors in a sheet-feed type image reader having multiple line sensors.

[0012] <Configuration of the image reading device> First, the basic configuration of the image reading device will be explained using an overall diagram of the image reading device and diagrams showing the image reading configuration. In the following explanation, the direction parallel to the direction in which the line sensor 106 that reads the document extends will be referred to as the main scanning direction (X direction), and the direction perpendicular to the main scanning direction will be referred to as the transport direction (Y direction). When the image reading device is installed on a horizontal plane, the X and Y directions are parallel to the horizontal direction, and the vertical direction (Z direction) is perpendicular to the X and Y directions. Note that the relationship between the X, Y, and Z directions and the horizontal and vertical directions is an example and is not limited to this example. Also, the Y direction is the transport direction when the document is transported in a non-skewed state. When the document is transported in a skewed state, the transport direction intersects the Y direction.

[0013] Figure 1(A) is a perspective view showing the external appearance of a sheet-fed scanner 100 as an example of an image reading device in Embodiment 1. As shown in Figure 1(A), the scanner 100 has a document feed slot 101 and a document feed tray 102 on the front side of the main body. The user places the leading edge of the document on the document feed tray 102 so that the center of the document is positioned in the center of the feed slot, and inserts the document into the document feed slot 101 by sliding it along the tray. The document feed slot 101 is designed to tolerate a certain degree of misalignment and tilt during insertion relative to the width of the document in the main scanning direction that the scanner 100 can read. The configuration of the document feeding path will be described later using Figure 1(B).

[0014] The document feed tray 102 may be provided with a guide member for positioning the document in the main scanning direction. The guide member can be, for example, fixed to one end of the document feed tray 102 in the main scanning direction and have a wall portion against which one end of the document in the main scanning direction can abut. In this case, the document is positioned at one end of the main scanning direction. A configuration in which the document is transported with one end of the document in the main scanning direction aligned with one end of the document transport path in the main scanning direction is called an end-reference configuration.

[0015] As another configuration of the guide member, for example, it can be configured to have a pair of moving parts that are provided on the document feeder 102 so as to be movable in the main scanning direction and can abut against both end portions of the document in the main scanning direction. In this case, by configuring the pair of moving parts to be movable while maintaining a symmetric positional relationship with respect to the center of the document feeder 102, the center of the document in the main scanning direction can be aligned with the center of the document feeder 102 in the main scanning direction. A configuration in which the document is conveyed in a state where the center of the document in the main scanning direction is aligned with the center of the document conveyance path in the main scanning direction is called a center reference configuration.

[0016] An operation unit 103 is provided on the upper surface of the scanner 100. The operation unit 103 has physical keys, a touch panel, an LCD panel, etc. The user can set the reading conditions and input the document size by operating the operation unit 103.

[0017] An upper cover 104 is provided on the upper surface of the scanner 100. The user can access the reading unit etc. inside the scanner 100 by opening the upper cover 104 upward, and can perform maintenance etc. of the scanner 100 in that state.

[0018] FIG. 1(B) is a cross-sectional view showing the internal configuration of the scanner 100. FIG. 1(C) is a top view showing the internal configuration of the scanner 100. In FIG. 1(B), the left side is the upstream side in the conveyance direction, the right side is the downstream side in the conveyance direction, and the document is conveyed in the +Y direction. The document 110 fed by the user via the document feeder 102 is discharged from the back of the main body through a planar conveyance path.

[0019] The document detection sensor 105 is a sensor that detects the insertion of a document 110. When the document detection sensor 105 detects the insertion of a document 110, the control unit 202 of the scanner 100 (see Figure 2) rotates the first transport roller 107 to pull the document 110 into the scanner 100. The edge detection sensor 112 detects the leading edge of the document 110 that has been pulled into the scanner 100 by the rotation of the first transport roller 107. The detection result of the edge detection sensor 112 is also used to determine the starting position for reading the document 110 and to detect the position of the trailing edge of the document 110.

[0020] Inside the scanner 100, the document 110 passes between the glass plate 109 and the document holder 111. The document holder 111 presses the document 110 against the glass plate 109 with a predetermined pressure. The document holder 111 is located on the opposite side of the document transport path from the line sensor (hereinafter referred to as CIS) 106. The CIS 106 consists of multiple chips arranged in the main scanning direction (X direction in the figure), and each chip is provided with a light-receiving element. The CIS 106 extends in the main scanning direction perpendicular to the transport direction of the document 110. The reading surface of the CIS 106 faces the glass plate 109, and it is designed so that the reading focus is located at the contact surface between the document 110 and the glass plate 109.

[0021] The second transport roller 108 is located downstream of the first transport roller 107 in the transport direction and rotates in accordance with the rotation of the first transport roller 107 by a belt (not shown). After the document 110 has passed the area where it is pressed against the glass plate 109 by the document holder 111, it is discharged downstream in the transport direction by the second transport roller 108.

[0022] The control unit 202 has a circuit board that controls the document detection sensor 105, the edge detection sensor 112, a motor (not shown) for rotating the first transport roller 107, the CIS 106, the operation unit 103, and the like.

[0023] As shown in Figure 1(C), the scanner 100 has multiple CIS106s (five in Example 1) arranged in a staggered pattern in the main scanning direction. To distinguish the five CIS106s, they are designated as CIS106a, CIS106b, CIS106c, CIS106d, and CIS106e, starting from the leftmost one in Figure 1(C), and the whole set of these is called CIS106. The CIS106s adjacent to each other in the main scanning direction are positioned with a staggered position in the transport direction, and are also positioned so that a portion of their main scanning direction overlaps.

[0024] In the example shown in Figure 1(C), CIS106e, which is adjacent to CIS106d, is positioned upstream of CIS106d in the transport direction. Furthermore, CIS106d and CIS106e are positioned to overlap within a predetermined range including the connecting position 113 in the main scanning direction.

[0025] The positions of CIS106a, CIS106c, and CIS106e in the transport direction are the same, and the positions of CIS106b and CIS106d in the transport direction are also the same. In other words, the multiple CIS106a to 106e consist of a group of CIS (CIS106a, CIS106c, CIS106e) positioned upstream in the transport direction and a group of CIS (CIS106b, CIS106d) positioned downstream. The CIS106 included in the upstream CIS group and the CIS106 included in the downstream CIS group are arranged alternately in the main scanning direction, so that the multiple CIS106 are arranged in a staggered pattern in the main scanning direction. The original document 110 inserted into the scanner 100 first passes through the CIS106 of the upstream CIS group, and then passes through the CIS106 of the downstream CIS group.

[0026] CIS106, located at the end in the main scanning direction, is included in the upstream CIS group. In the example in Figure 1(C), CIS106a and CIS106e, which are end line sensors located at the end in the main scanning direction, are included in the upstream CIS group. In other words, the end line sensors CIS106a and CIS106e are located upstream in the transport direction from the adjacent CIS (CIS106b, CIS106d). In Embodiment 1, the number of line sensors is odd, and the end line sensors include CIS106a, located at one end in the main scanning direction, and CIS106e, located at the other end.

[0027] Figure 1(C) shows how a document 110 with the maximum width in the main scanning direction that can be read by the scanner 100 is being transported in an unskewed state. The transport direction M1 (referred to as the reference transport direction) in the unskewed state is the direction perpendicular to the main scanning direction (Y direction). Among the multiple CIS106s, the end line sensors CIS106a and CIS106e, which are located at the ends of the main scanning direction, have end regions 106L and 106R outside the effective area through which the document 110 passes when reading the document 110 with the maximum width. The end region 106L of CIS106a is at the left end (-X direction) of CIS106a, and the end region 106R of CIS106e is at the right end (+X direction) of CIS106e.

[0028] The control unit 202 transports the original document 110 in the transport direction to multiple CIS 106a to 106e and performs a process of stitching together the image data read by the multiple CIS 106a to 106e based on the stitching position 113. In this way, the control unit 202 generates an overall image of the original document 110.

[0029] Figure 2 is a block diagram showing the hardware configuration of the scanner 100 in Embodiment 1. The control unit 202 controls image reading and other functions. The control unit 202 includes a CPU 204, a memory 208, a motor driver 207, an interface (IF) unit 203, an A / D conversion unit 206, and a power supply unit 205. The operation unit 103 has a touch panel with an LCD (Liquid Crystal Display). The LCD of the operation unit 103 displays information regarding the document 110 to be read and the settings of the scanner 100, etc., according to instructions from the CPU 204. The user can also change inputs to the scanner 100, such as various settings, by operating the touch panel on the operation unit 103 while checking the information displayed on the LCD of the operation unit 103.

[0030] The motor driver 207 rotates the first transport roller 107 and the second transport roller 108. The CPU 204 controls the drive of the transport motor 201. The CPU 204 controls the motor driver 207. The first transport roller 107, the second transport roller 108, the transport motor 201, the motor driver 207, and the CPU 204 are transport means for transporting the document. The outputs of the document detection sensor 105 and the edge detection sensor 112 are input to the CPU 204. Based on the changes in the output signals of these sensors and the state of the transport motor 201, the CPU 204 performs control such as determining the drive timing of multiple CIS 106 (CIS 106a to 106e).

[0031] Multiple CIS106 units output the read images as analog signals to the control unit 202. The analog signals output from the multiple CIS106 units are converted into digital signals by each A / D conversion unit 206 and input to the CPU 204. The CPU 204 processes the data converted into digital signals by each A / D conversion unit 206 and transmits it as image data to an external device connected via USB or LAN, etc., through the IF unit 203. The power supply unit 205 generates the necessary voltage for each unit and supplies power. The memory 208 can store image data for multiple lines.

[0032] <Manuscript reading process> The following describes the process of reading the document 110 using CIS106 and detecting the skewness of the document 110, using Figure 3 as an example.

[0033] In step S301, the CPU 204 receives input from the user pressing the start scan button on the control panel 103. In this step, the scanner 100 enters a state where it is waiting for a document to be inserted.

[0034] In step S302, the CPU 204 determines whether it has detected the insertion of the document 110 set by the user. If the result of this step is true, the CPU 204 executes step S303. On the other hand, if the result of this step is false, the CPU 204 repeats the determination in this step.

[0035] In step S303, the CPU 204 controls the transport motor 201 to transport the document 110 to the reading start position.

[0036] In step S304, the CPU 204 starts the image reading operation and saves the data acquired through reading (read data) to the memory 208.

[0037] In step S305, the CPU 204 obtains data for diagonal detection from the data acquired in step S304. The processing in this step will be described later.

[0038] In step S306, the CPU 204 determines whether skew has been detected based on the skew detection data acquired in step S305. If the result of this step is true (skew has been detected), the CPU 204 executes step S307. On the other hand, if the result of this step is false (skew has not been detected), the CPU 204 executes step S308.

[0039] In step S307, the CPU 204 stops the transport and terminates the reading, and also issues an error notification that includes information indicating that skew has been detected. For example, the CPU 204 issues the error notification by displaying an error message on the LCD of the operation unit 103, generating a beep sound, or illuminating a warning lamp. The CPU 204 that executes step S307 is a control means that controls the transport means to stop transporting the document when it is detected that the document is skewed, and is a notification means that informs the user that the document is skewed.

[0040] In step S308, the CPU 204 determines whether the reading of a predetermined length has been completed. If the determination result in this step is true, the CPU 204 executes step S309. On the other hand, if the determination result in this step is false (i.e., the reading of a predetermined length has not been completed), the CPU 204 returns to step S305 and continues the reading operation until the reading of a predetermined length is completed. Whether or not the reading of a predetermined length has been completed can be determined, for example, by whether or not a transport amount corresponding to the distance between the end detection sensor 112 and the CIS 106 of the downstream CIS group has been transported since the passage of the trailing end of the document 110 was detected by the end detection sensor 112.

[0041] In step S309, the CPU 204 terminates the image reading operation and transports the document 110 to the paper output position.

[0042] <Data acquisition process for detecting skew> The process of acquiring data for skew detection based on the reading data from CIS106 (step S305 in Figure 3) will be explained below with reference to Figures 4 and 5. Figures 4(A) to 4(C) show the process of acquiring data for skew detection.

[0043] Figure 4(A) shows how the document 110 is transported at an angle during document scanning. The arrow R indicates the transport direction of the document when it is at an angle. The document 110 may be transported at an angle during document scanning due to factors such as the engagement of the rollers when opening and closing the cover, the slippage of the document 110, and the tilt when the document is set. The transport direction M2 when the document is at an angle is tilted with respect to the reference transport direction M1. When the document 110 is at an angle, it can reach the end of the transport path in the main scanning direction and interfere, causing a jam. If the document 110 jams in the scanner 100, it can lead to damage to the document 110, so it is necessary to suppress the occurrence of jams. By detecting the skew of the document 110 as early as possible, the occurrence of jams can be suppressed.

[0044] Figures 4(B) and 4(C) show a method for detecting skew from the reading results of CIS106. In Example 1, the end regions 106L and 106R of CIS106a and CIS106e at both ends in the main scanning direction, which the document 110 does not pass through when the document 110 is not skewed, are used as the skew detection area. The reflectance of the opposing region 111L of the document holder 111 that faces the end region 106L of CIS106a, and the opposing region 111R that faces the end region 106R of CIS106e, is made lower than the reflectance of the other regions. For example, the opposing regions 111L and 111R of the document holder 111 are colored with a low-gradation color such as black. Note that the method for lowering the reflectance is not limited to this. For example, the opposing regions 111L and 111R may be formed from a light-transmitting material. The length of the edge regions 106L and 106R of the CIS106, which are used as the skew detection section, in the main scanning direction is set based on the length obtained by subtracting the maximum main scanning direction width (maximum reading width) that the scanner 100 can read from the width of the entire CIS106 in the main scanning direction. However, to take into account variations in the position where the user sets the document, the length of the edge regions 106L and 106R in the main scanning direction may also be set based on the length obtained by subtracting "maximum reading width + margin" from the width of the entire CIS106 in the main scanning direction.

[0045] Figure 4(B) shows the scanning process when the document 110 is not skewed. When the document 110 is not skewed, as shown in Figure 1(C), the document 110 does not pass through the edge regions 106L and 106R of the CIS 106. Therefore, as shown in Figure 4(B), the edge regions 106L and 106R of the CIS 106 detect reflected light from the opposing regions 111L and 111R of the document holder 111. Consequently, the scanning result has low grayscale.

[0046] Figure 4(C) shows the scanning process when the original document 110 is skewed. Original document 1 In the case of skewness 10, for example, when skewed to the left as shown in Figure 4(A), the left edge of the document 110 passes through the left edge region 106L of the CIS 106. Therefore, as shown in Figure 4(C), the left edge region 106L of the CIS 106 detects reflected light from the document 110. Consequently, the edge region 106L of the CIS 106 results in a reading with higher gradation compared to Figure 4(B).

[0047] Figure 5 is a flowchart showing the data acquisition process for detecting skew.

[0048] In step S501, the CPU 204 acquires the data read from the edge regions 106L and 106R of the CIS 106, respectively.

[0049] In step S502, the CPU 204 generates judgment data for determining skew detection from the data of the edge regions 106L and 106R acquired in step S501. As a data processing method, for example, data is generated by removing pixels with high and low gradation values ​​within a predetermined range from the data acquired in step S501, and noise data is removed by averaging in the main scanning direction. By performing such data processing on the acquired data of the edge regions 106L and 106R, judgment data for the edge regions 106L and 106R is generated. The judgment data is the first image read by the edge line sensors (CIS106a, CIS106e) in the edge regions 106L and 106R while the document is being transported.

[0050] In step S503, the CPU 204 compares the judgment data generated in step S502 with pre-set reference data. The reference data is a pre-set fixed value. Alternatively, the CPU 204 may generate the reference data. For example, the CPU 204 sets the reference data based on data acquired from the edge regions 106L and 106R at fixed timings such as when the scanner 100 is powered on or when the image reading operation starts. In this case, the CPU 204 may set the data as reference data after noise reduction and averaging processing have been performed on the acquired data, similar to step S502. When generating reference data in this way, accurate skew detection is possible because the reference data can be set each time even if there are changes over time such as a decrease in light intensity in the output of the CIS 106. In this case, the reference data is the second image read by the edge line sensors (CIS 106a, CIS 106e) in the edge regions 106L and 106R when no document is being transported.

[0051] In step S504, the CPU 204 determines, based on the comparison results from step S503, whether the gradation value of the judgment data is greater than or equal to the threshold Jt than the gradation value of the reference data. If the determination result in this step is true, the CPU 204 executes step S505. In this case, the CPU 204 determines that the first image is an image that shows that the original document 110 is present in the edge regions 106L and 106R, and detects that the original document 110 is skewed. If the determination result is false, the CPU 204 determines that no skew has been detected and terminates this flow. The threshold Jt is set to an intermediate gradation value, assuming that the gradation of the original document is a high gradation such as white. The threshold Jt may be a fixed value, or it may be varied according to the usage environment based on the data of the CIS 106 acquired when the scanner 100 is powered on.

[0052] In step S505, the CPU 204 sets the skew detection flag. By setting the skew detection flag, the CPU 204 determines that skew has been detected in step S306 in Figure 3. Here, if the determination result in step S504 is true, it means that the document has been detected as skewed. At the time when the skew of the document is detected, a jam may not have occurred yet.

[0053] The CPU 204, which executes steps S501 to S505, is based on the first image. This is a detection means for detecting the status of document transport.

[0054] As described above, when the document 110 is skewed, the gradation of the reading results in the edge regions 106L and 106R of the CIS 106 becomes higher compared to when the document 110 is not skewed. Therefore, the skew of the document 110 can be detected based on the reading results of the edge regions 106L and 106R of the CIS 106.

[0055] Furthermore, CIS106 consists of multiple CIS106a to 106e arranged in a staggered pattern in the main scanning direction, and the end regions 106L and 106R are parts of CIS106a and CIS106e included in the upstream CIS group. Therefore, compared to the case where a part of CIS106 included in the downstream CIS group is used as a skew detection unit, skew of the document 110 can be detected earlier, and as a result, jamming of the document 110 can be suppressed in advance.

[0056] Furthermore, among the multiple CIS106s, CIS106a and 106e, located at both ends in the main scanning direction, are both included in the upstream CIS group. Therefore, whether the document is positioned based on the center or the edge, document skew can be detected early.

[0057] Furthermore, the reflectivity of the opposing regions 111L and 111R of the document holder 111, which correspond to the edge regions 106L and 106R of the CIS 106 used as the skew detection unit, is reduced. As a result, even when scanning a document 110 with high reflectivity, skew can be detected accurately. Therefore, skew detection is possible regardless of the type of document 110.

[0058] (Example 2) Example 2 describes an example in which the present invention is applied to an image reading device that uses a sheet-feed method and is composed of multiple line sensors, wherein the document positioning configuration is the edge-reference configuration described above. Below, the differences from Example 1 will be mainly described, and explanations of the same content as in Example 1 will be omitted as appropriate.

[0059] Figure 6 shows the data acquisition process for skew detection in an edge-referenced image reading device.

[0060] As shown in Figure 6, the scanner 100 of Example 2 has an even number (four in Example 2) of CIS106 arranged in a staggered pattern in the main scanning direction. To distinguish the four CIS106, they are designated as CIS106a, CIS106b, CIS106c, and CIS106d, starting from the leftmost one in Figure 6. The relative positions of each CIS106 are the same as in Example 1. The CIS106 consists of an upstream CIS group (CIS106a, 106c) and a downstream CIS group (CIS106b, CIS106d).

[0061] In a center-reference configuration where the center of the document in the main scanning direction is positioned at the center of the scanner 100 in the main scanning direction, jams can occur on both sides of the main scanning direction. In an edge-reference configuration where one end of the document in the main scanning direction is positioned at one end of the scanner 100 in the main scanning direction, the reference end of the document is transported close to the reference end of the scanner, so the probability of jams occurring is high at the reference end of the document. On the other hand, the end of the document opposite to the reference side is transported farther from the opposite end of the scanner, so the probability of jams occurring is low.

[0062] As in Example 2, when the number of CIS106s is even, only the CIS106 located at one end of the main scanning direction (in Figure 6, CIS106a located at the left end) is included in the upstream CIS group. The CIS106 located at the other end of the main scanning direction (in Figure 6, CIS106d located at the right end) is included in the downstream CIS group. Therefore, in the end-referenced scanner 100, multiple CIS106s are arranged such that the CIS106 located at the reference end is included in the upstream CIS group. By detecting skew early on the reference side, where jamming is more likely to occur, jamming can be suppressed.

[0063] The scanner 100 in Example 2 has an edge-reference configuration where the left side is the reference side in Figure 6. As shown in Figure 6, since the CIS 106a located at the reference side (left side) edge is included in the upstream CIS group, the edge region 106L of CIS 106a can detect the skew of the document 110 at an early stage.

[0064] Figure 7 is a flowchart showing the data acquisition process for detecting skew.

[0065] In step S701, the CPU 204 acquires the data read from the reference end region 106L of the CIS 106.

[0066] From here on, the processing in steps S702 to S705 is the same as the processing in steps S502 to S505 in the flowchart of Figure 5, so the explanation will be omitted.

[0067] As described above, in a scanner 100 with an even number of CIS106s, by including the CIS106s at the reference end, which have a high probability of jamming, in the upstream CIS group, it becomes possible to detect the skew of the document 110 early. Therefore, if the scanner 100 has an edge-based configuration, it is possible to suppress the occurrence of jamming in advance, regardless of the number of CIS106s.

[0068] <Other examples> The present invention can also be realized by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0069] This embodiment includes the following configuration. (Composition 1) A means of transporting the manuscript, A plurality of line sensors extending in a main scanning direction perpendicular to the document transport direction, wherein the plurality of line sensors are arranged in a staggered pattern along the main scanning direction, An image reading device comprising, which generates an image of a document by concatenating images read by a plurality of line sensors while transporting the document to a plurality of line sensors in the transport direction, Of the plurality of line sensors, the end line sensor located at the end in the main scanning direction is positioned upstream in the transport direction from the line sensor adjacent to the end line sensor. The end line sensor has an end region outside the effective region through which the document passes. An image reading device characterized by having a detection means for detecting the transport state of a document based on a first image, which is an image read by the end line sensor in the end region while the document is being transported by the transport means. (Configuration 2) The image reading device according to configuration 1, wherein the detection means detects that the document is skewed if the first image is an image indicating that the document is present in the edge region. (Composition 3) The image reading device according to configuration 1 or 2, wherein the detection means detects the document transport status by comparing a second image, which is an image read by the end line sensor in the end region when the document is not being transported by the transport means, with the first image. (Composition 4) The image reading device according to configuration 3, wherein the detection means detects that the document is skewed when the difference between the grayscale value of the first image and the grayscale value of the second image is greater than a threshold. (Composition 5) An image reading device according to any one of configurations 1 to 4, further comprising a control means for controlling the transport means to stop transporting the document when the detection means detects that the document is skewed. (Composition 6) An image reading device according to any one of configurations 1 to 5, further comprising a notification means for notifying the user when the detection means detects that the document is skewed. (Composition 7) It has a document holder located on the opposite side of the plurality of line sensors across the document transport path, The image reading device according to any one of configurations 1 to 6, wherein the reflectance of the region of the end line sensor facing the end region in the document holder is lower than the reflectance of the other regions. (Configuration 8) The transport means is configured to transport the document while aligning one end of the document in the main scanning direction with the one end of the document transport path in the main scanning direction. The image reading device according to any one of configurations 1 to 7, wherein the end line sensor is a line sensor located at one end in the main scanning direction. (Composition 9) The image reading device according to configuration 8, wherein the number of line sensors is even. (Composition 10) The number of line sensors is odd, and the end line sensors include a line sensor located at one end and a line sensor located at the other end in the main scanning direction, as described in any one of configurations 1 to 7. (Composition 11) The image reading device according to configuration 10, wherein the transport means is configured to transport the document while aligning the center of the document in the main scanning direction with the center of the document transport path in the main scanning direction. [Explanation of Symbols]

[0070] 100: Scanner, 106: Line sensor (CIS), 107: First transport roller, 108: Second transport roller, 110: Document, 201: Transport motor, 204: CPU

Claims

1. A means of transporting the manuscript, A plurality of line sensors extending in a main scanning direction perpendicular to the document transport direction, wherein the plurality of line sensors are arranged in a staggered pattern along the main scanning direction, An image reading device comprising, which generates an image of a document by concatenating images read by a plurality of line sensors while transporting the document to a plurality of line sensors in the transport direction, Of the plurality of line sensors, the end line sensor located at the end in the main scanning direction is positioned upstream in the transport direction from the line sensor adjacent to the end line sensor. The end line sensor has an end region outside the effective region through which the document passes. An image reading device characterized by having a detection means for detecting the transport state of a document based on a first image, which is an image read by the end line sensor in the end region while the document is being transported by the transport means.

2. The image reading device according to claim 1, wherein the detection means detects that the document is skewed if the first image is an image indicating that a document is present in the edge region.

3. The image reading device according to claim 1 or 2, wherein the detection means detects the document transport status by comparing a second image, which is an image read by the end line sensor in the end region when the document is not being transported by the transport means, with the first image.

4. The image reading device according to claim 3, wherein the detection means detects that the document is skewed when the difference between the grayscale value of the first image and the grayscale value of the second image is greater than a threshold.

5. The image reading device according to claim 1 or 2, further comprising a control means for controlling the transport means to stop transporting the document when the detection means detects that the document is skewed.

6. The image reading device according to claim 1 or 2, further comprising a notification means for notifying the user when the detection means detects that the document is skewed.

7. It has a document holder located on the opposite side of the plurality of line sensors across the document transport path, The image reading device according to claim 1 or 2, wherein the reflectance of the region of the end line sensor facing the end region in the document holder is lower than the reflectance of the other regions.

8. The transport means is configured to transport the document while aligning one end of the document in the main scanning direction with the one end of the document transport path in the main scanning direction. The image reading device according to claim 1 or 2, wherein the end line sensor is a line sensor located at one end in the main scanning direction.

9. The image reading device according to claim 8, wherein the number of line sensors is even.

10. The image reading device according to claim 1 or 2, wherein the number of line sensors is odd, and the end line sensors include a line sensor located at one end and a line sensor located at the other end in the main scanning direction.

11. The image reading device according to claim 10 is configured such that the transport means transports the document while aligning the center of the document in the main scanning direction with the center of the document transport path in the main scanning direction. Place.

Images