Document conveying device and roller control method

Abstract

To prevent the document jam of a two-folded document.SOLUTION: In a scanner 1, a processor 21 is configured to: execute a first rotation mode in which a document on an outermost side on a pick roller 41 side among the plurality of documents placed on a sheet feeding tray 11 can be separated from the plurality of documents by rotating the pick roller 41 in the counterclockwise direction and simultaneously rotate a brake roller 42 in the counterclockwise direction; after the execution of the first rotation mode, execute a second rotation mode of determining whether or not the document being conveyed to a conveyance path P from the sheet feeding tray 11 is the two-folded document; upon determining that the document being conveyed is the two-folded document, stop the pick roller 41 and simultaneously rotate the brake roller 42 in the clockwise rotation; and after the execution of the second rotation mode, execute a third rotation mode of rotating a first roller in a first direction and simultaneously rotate a second roller in a second direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to Document transport The present invention relates to an apparatus and a roller control method. [Background technology]

[0002] Some image reading devices read images of multiple documents placed on a paper feed tray in sequence. Examples of image reading devices include scanners and copy machines. The multiple documents placed on the paper feed tray are taken into the image reading device in sequence, starting from the top document of the multiple documents placed on the paper feed tray (hereinafter sometimes referred to as the "top document"), or the bottom document of the multiple documents placed on the paper feed tray (hereinafter sometimes referred to as the "bottom document"). Hereinafter, an image reading device of the type that takes in multiple documents placed on the paper feed tray in sequence starting from the top document is referred to as an "upper-loading type device," and an image reading device of the type that takes in multiple documents placed on the paper feed tray in sequence starting from the bottom document is referred to as a "lower-loading type device."

[0003] The separation of the topmost or bottommost document from the multiple documents placed on the paper feed tray is sometimes performed using a pick roller and a brake roller. The pick roller and the brake roller are a pair of rollers arranged opposite each other near the start of the transport path along which the documents are transported, and separate the multiple documents placed on the paper feed tray in order, starting from the topmost or bottommost document, and transport the separated documents from the paper feed tray to the transport path. The pick roller and the brake roller rotate in the same direction, making it possible to separate the topmost or bottommost document from the multiple documents placed on the paper feed tray. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-302376 A [Patent Document 2] JP 2012-188279 A [Patent Document 3] JP 2017-210368 A Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to unfolded documents (hereinafter sometimes referred to as "unfolded documents"), documents that have been folded in half (hereinafter sometimes referred to as "folded documents") may be placed on the paper feed tray. For example, when an A3-sized document is folded in half, an A4-sized folded document is completed. In the following, in a folded document, the upper sheet may be referred to as the "upper sheet" and the lower sheet may be referred to as the "lower sheet." In other words, a folded document is a single document in which the upper sheet and the lower sheet are joined via a fold.

[0006] When the above-mentioned separation of the document by the pick roller and the brake roller is performed on a document folded in half, an angled "misalignment" (hereinafter sometimes referred to as "document misalignment") may occur between the upper and lower sheets. For example, in a top-loading type device, the upper sheet contacts the pick roller while the lower sheet contacts the brake roller, causing document misalignment of the lower sheet relative to the upper sheet. Also, for example, in a bottom-loading type device, the lower sheet contacts the pick roller while the upper sheet contacts the brake roller, causing document misalignment of the upper sheet relative to the lower sheet.

[0007] When a folded document with a large document misalignment is transported along the transport path, the possibility of a document jam occurring along the transport path increases.

[0008] Therefore, the present disclosure proposes a technique that can prevent document jams of documents folded in half. [Means for solving the problem]

[0009] The image reading device of the present disclosure includes a tray on which an original is placed, a transport path through which the original is transported, an image sensor that reads an image of the original being transported through the transport path, a pair of rollers that transport the original from the tray to the transport path, and a processor. The pair of rollers is a first roller and a second roller that are arranged opposite each other with the original sandwiched between them. The processor executes a first rotation mode in which the outermost original on the side of the first roller among a plurality of originals placed on the tray can be separated from the plurality of originals by rotating the first roller in a first direction and simultaneously rotating the second roller in the first direction. After executing the first rotation mode, the processor determines whether the original being transported, which is the original being transported from the tray to the transport path, is a folded original that is a document that has been folded in half. When the processor determines that the original being transported is the folded original, the processor executes a second rotation mode in which the first roller is stopped and the second roller is rotated in a second direction opposite to the first direction. Furthermore, after executing the second rotation mode, the processor executes a third rotation mode in which the first roller is rotated in the first direction and the second roller is rotated in the second direction at the same time. Effect of the Invention

[0010] According to the disclosed technique, document jams of documents folded in half can be prevented. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating a configuration example of a scanner according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating a configuration example of the scanner according to the first embodiment of the present disclosure. [Diagram 3] FIG. 3 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 11] FIG. 11 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 12] FIG. 12 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 14] FIG. 14 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 15] FIG. 15 is a diagram for explaining an example of the operation of the scanner according to the first embodiment of the present disclosure. [Figure 16] FIG. 16 is a flowchart illustrating an example of a processing procedure in the scanner according to the first embodiment of the present disclosure. [Figure 17] FIG. 17 is a flowchart illustrating an example of a processing procedure in the scanner according to the second embodiment of the present disclosure. [Figure 18] FIG. 18 is a diagram illustrating a configuration example of a scanner according to the third embodiment of the present disclosure. [Figure 19] FIG. 19 is a diagram illustrating a configuration example of a scanner according to the third embodiment of the present disclosure. [Figure 20] FIG. 20 is a diagram for explaining an example of the operation of the scanner according to the third embodiment of the present disclosure. [Figure 21] FIG. 21 is a diagram for explaining an example of the operation of the scanner according to the third embodiment of the present disclosure. [Figure 22]FIG. 22 is a flowchart illustrating an example of a processing procedure in the scanner according to the third embodiment of the present disclosure. [Diagram 23] FIG. 23 is a diagram illustrating a configuration example of a scanner according to a fourth embodiment of the present disclosure. [Figure 24] FIG. 24 is a diagram illustrating a configuration example of a scanner according to a fourth embodiment of the present disclosure. [Diagram 25] FIG. 25 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Figure 26] FIG. 26 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Figure 27] FIG. 27 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Figure 28] FIG. 28 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Figure 29] FIG. 29 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Diagram 30] FIG. 30 is a diagram for explaining an example of the operation of the scanner according to the fourth embodiment of the present disclosure. [Diagram 31] FIG. 31 is a flowchart illustrating an example of a processing procedure in the scanner according to the fourth embodiment of the present disclosure. [Diagram 32] FIG. 32 is a diagram illustrating a configuration example of a scanner according to a fifth embodiment of the present disclosure. [Diagram 33] FIG. 33 is a diagram illustrating a configuration example of a scanner according to a fifth embodiment of the present disclosure. [Diagram 34] FIG. 34 is a flowchart illustrating an example of a processing procedure in the scanner according to the fifth embodiment of the present disclosure. [Diagram 35] FIG. 35 is a diagram illustrating a configuration example of a scanner according to the sixth embodiment of the present disclosure. [Diagram 36] FIG. 36 is a diagram illustrating a configuration example of a scanner according to the sixth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same configurations and steps performing the same processes are denoted by the same reference numerals.

[0013] In the following, a scanner will be described as an example of an image reading device. However, the image reading device to which the disclosed technology can be applied is not limited to a scanner. For example, the disclosed technology can be applied to image reading devices other than scanners, such as copy machines.

[0014] [Example 1] <Scanner configuration> 1 and 2 are diagrams showing a configuration example of a scanner according to a first embodiment of the present disclosure. The scanner 1 shown in Figs. 1 and 2 is a trade-in type device.

[0015] In FIG. 1, the scanner 1 includes a paper feed tray 11, a lower housing 12, an upper housing 13, a document insertion port 14, a transport path P, transport rollers 26-1 and 26-2, image sensors 17-1 and 17-2, discharge rollers 27-1 and 27-2, a document discharge port 15, a processor 21, a memory 22, and a display 28. A plurality of documents D can be placed on the paper feed tray 11. A transport path P along which the documents D are transported is formed between the upper housing 13 and the lower housing 12. Hereinafter, the image sensors 17-1 and 17-2 may be collectively referred to as "image sensor 17". An example of the image sensor 17 is a contact image sensor (CIS). An example of the processor 21 is a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), or the like. Examples of the memory 22 include a random access memory (RAM), a read only memory (ROM), a flash memory, etc. An example of the display 28 is a liquid crystal display (LCD).

[0016] 1 and 2, the scanner 1 has a pick roller 41, a brake roller 42, and an area sensor 31. The area sensor 31 has a plurality of imaging elements arranged two-dimensionally in the vertical and horizontal directions, and captures a two-dimensional image of the document D transported on the transport path P. The area sensor 31 captures an image of the entire width direction near the leading end of the document D in the transport direction CD transported from the paper feed tray 11 to the transport path P. The area sensor 31 is an example of an "imaging unit" that captures a two-dimensional image of the document D.

[0017] It is preferable to use an area sensor having a wide-angle lens capable of capturing an image of the entire width of the original D as the area sensor 31. If it is difficult to capture an image of the entire width of the original D with a single area sensor, multiple area sensors may be arranged along the width of the original D, and the processor 21 may combine multiple images captured by the multiple area sensors to obtain an image of the entire width of the original D.

[0018] The upper housing 13 houses a brake roller 42, an area sensor 31, a transport roller 26-1, an image sensor 17-1, a discharge roller 27-1, and a display 28. The lower housing 12 houses a processor 21, a memory 22, a pick roller 41, a transport roller 26-2, an image sensor 17-2, and a discharge roller 27-2. Hereinafter, the transport rollers 26-1 and 26-2 may be collectively referred to as "transport rollers 26."

[0019] The pick roller 41 and the brake roller 42 are a pair of rollers arranged opposite each other with the document D sandwiched therebetween near the start point of the transport path P along which the document D is transported (i.e., near the end point of the document insertion port 14 through which the document D is inserted). The pick roller 41 rotates in a left-handed (counterclockwise) direction, while the brake roller 42 can rotate both left-handed and right-handed (clockwise) directions. The rotation direction of the brake roller 42 is switched by the processor 21. When no document D is present between the pick roller 41 and the brake roller 42, the outer circumferential surface of the pick roller 41 and the outer circumferential surface of the brake roller 42 come into contact with each other. Hereinafter, the region where the outer circumferential surface of the pick roller 41 and the outer circumferential surface of the brake roller 42 come into contact with each other may be referred to as a "nip region." In the following, the rotation of the pick roller 41 and the brake roller 42 in the left-handed (counterclockwise) direction may be referred to as "forward rotation," and the rotation of the pick roller 41 and the brake roller 42 in the right-handed (clockwise) direction may be referred to as "reverse rotation."

[0020] The transport roller 26-1 and the discharge roller 27-1 rotate clockwise, while the transport roller 26-2 and the discharge roller 27-2 rotate counterclockwise, causing the document D to be transported along the transport path P in the transport direction CD.

[0021] Since the scanner 1 is a trade-in type device, when multiple documents D are placed on the paper feed tray 11, the pick roller 41 and the brake roller 42 rotate forward at the same time, so that each document D is separated from the multiple documents D placed on the paper feed tray 11 in order from the bottom document to the top document, and the separated documents D are transported from the paper feed tray 11 to the transport path P via the document insertion port 14. That is, the scanner 1 has a rotation mode (hereinafter sometimes referred to as a "first rotation mode") in which the outermost document (hereinafter sometimes referred to as the "outermost document") on the pick roller 41 side among the multiple documents D placed on the paper feed tray 11 can be separated from the multiple documents D by rotating the pick roller 41 in a counterclockwise direction and simultaneously rotating the brake roller 42 in a counterclockwise direction. In a trade-in type device, the bottom document corresponds to the outermost document, and in a top-up type device, the top document corresponds to the outermost document.

[0022] Each document D taken into the transport path P is transported along the transport path P toward the image sensor 17 as the transport rollers 26-1 and 26-2 rotate, and an image of each document D being transported along the transport path P is read by the image sensor 17 as the document D is transported. The top surface of the document D is read by the image sensor 17-1, and the bottom surface of the document D is read by the image sensor 17-2.

[0023] After being read by the image sensor 17, the document D is discharged from the document discharge port 15 by the rotation of the discharge rollers 27-1 and 27-2.

[0024] Here, the brake roller 42 applies a transport load in the opposite direction to the transport direction CD (hereinafter, sometimes referred to as a "reverse load") to the outermost document among the multiple documents D placed on the paper feed tray 11. The reverse load is set to a constant value that is greater than the frictional force between two documents stacked vertically (i.e., the frictional force generated between the lower surface of the upper document and the upper surface of the lower document among the two documents stacked vertically), and is smaller than the frictional force of the pick roller 41 on the document D that remains last in the paper feed tray 11. Also, the frictional force of the pick roller 41 on the document D is greater than the frictional force between the two documents stacked vertically. Therefore, while the multiple documents D remain on the paper feed tray 11, only the outermost document among the multiple documents D is separated and transported to the transport path P, while the document D that remains last on the paper feed tray 11 is transported to the transport path P by the pick roller 41. As described above, the brake roller 42 applies a reverse load to the document D placed on the paper feed tray 11 in the nip area.

[0025] <Scanner operation> 3 to 15 are diagrams for explaining operation examples of the scanner according to the first embodiment of the present disclosure. Operation example 1 and operation example 2 will be explained below.

[0026] <Example of operation 1 (Fig. 3-6)> 3 to 5 are side views showing the transition of the state of the document over time in the first operational example, and FIG. 6 is a top view corresponding to the side view of FIG.

[0027] 3 to 6 is an operation example when a plurality of documents DA, DB, DC, DD, DE, and DF are placed on the paper feed tray 11. Documents DA, DB, DC, DD, DE, and DF are all unfolded documents, and among documents DA, DB, DC, DD, DE, and DF, document DA is the outermost document.

[0028] As shown in FIG. 3, when the documents DA, DB, DC, DD, DE, and DF are placed on the paper feed tray 11 and the “scan start button” (not shown) on the scanner 1 is pressed, the pick roller 41 and the brake roller 42 start rotating forward.

[0029] Next, as shown in FIG. 4, when the documents DA and DB reach the pick roller 41 and the brake roller 42, the document DA comes into contact with the pick roller 41, and the document DB comes into contact with the brake roller 42.

[0030] Focusing on the documents DA and DB, since both the pick roller 41 and the brake roller 42 are rotating in the forward direction, the document DA is separated from the document DB, and only the document DA is transported to the transport path P, as shown in Fig. 5. Furthermore, since the documents DA and DB are two unfolded documents independent of each other, the behavior of the document DB is not affected by the behavior of the document DA. Therefore, in a state in which the document DA passes through the nip area while the document DB remains near the nip area as shown in Fig. 5, no document misalignment occurs between the documents DA and DB, as shown in Fig. 6.

[0031] <Example of operation 2 (Fig. 7-15)> Figures 7 to 9, 12, and 14 are side views showing the state of the document that changes over time in operation example 2, Fig. 10 is a top view corresponding to the side view of Fig. 9, Fig. 13 is a top view corresponding to the side view of Fig. 12, and Fig. 15 is a top view corresponding to the side view of Fig. 14. Also, Fig. 11 is an enlarged view of the top view of Fig. 10.

[0032] Operation example 2 shown in Figs. 7 to 15 is an operation example when a plurality of documents, documents D1, D2, D3, D4, and D5, are placed on the paper feed tray 11. Document D1 is a document folded in half, while documents D2, D3, D4, and D5 are unfolded documents. Furthermore, document D1 is the outermost document among documents D1, D2, D3, D4, and D5. Furthermore, document D1, which is a document folded in half, is formed of upper side paper D1A and lower side paper D1B.

[0033] As shown in FIG. 7, when documents D1, D2, D3, D4, and D5 are placed on paper feed tray 11 and a "scan start button" (not shown) on scanner 1 is pressed, pick roller 41 and brake roller 42 start rotating forward.

[0034] Next, as shown in FIG. 8, when the document D1 reaches the pick roller 41 and the brake roller 42, the lower sheet D1B comes into contact with the pick roller 41 and the upper sheet D1A comes into contact with the brake roller 42.

[0035] Here, when focusing on the upper side sheet D1A and the lower side sheet D1B forming the document D1, since both the pick roller 41 and the brake roller 42 are rotating forward, the upper side sheet D1A remains near the nip area while the lower side sheet D1B is transported to the transport path P as shown in Fig. 9. Furthermore, since the upper side sheet D1A and the lower side sheet D1B are joined via a fold and form one document D1, the behavior of the upper side sheet D1A is affected by the behavior of the lower side sheet D1B. Therefore, if the upper side sheet D1A remains near the nip area while the lower side sheet D1B is transported to the transport path P, a document misalignment having a misalignment angle θ and a misalignment amount δ occurs between the lower side sheet D1B and the upper side sheet D1A, for example, as shown in Figs. 10 and 11.

[0036] Therefore, at the time when the processor 21 predicts that the document D being transported from the paper feed tray 11 to the transport path P (hereinafter, may be referred to as the "document being transported") will be in the state shown in Figures 10 and 11, the processor 21 temporarily stops the pick roller 41 and the brake roller 42 and causes the area sensor 31 to capture an image of the vicinity of the leading edge of the document being transported in the transport direction CD. Then, based on the image captured by the area sensor 31 (hereinafter, may be referred to as the "captured image"), the processor 21 determines whether the document being transported is a document folded in half or not. The enlarged view shown in Figure 11 corresponds to the captured image from which the image of the brake roller 42 is omitted.

[0037] For example, when the deviation angle θ in the captured image is equal to or greater than the threshold value THA, the processor 21 determines that the document being transported is a folded document, and when the deviation angle θ is less than the threshold value THA, the processor 21 determines that the document being transported is an unfolded document.

[0038] Furthermore, when the processor 21 determines that the document being conveyed is a document folded in half, it calculates the amount of deviation δ according to formula (1) based on the deviation angle θ and length l (FIG. 11) acquired from the captured image. The length l corresponds to the length of the oblique side near the leading edge of the document folded in half in the captured image. The processor 21 can acquire the deviation angle θ and length l from the captured image, for example, by using image analysis on the captured image. δ = l sinθ …(1)

[0039] Furthermore, the processor 21 calculates the rotation angle θb of the reverse rotation of the brake roller 42 having a radius r according to the formula (2) based on the deviation amount δ calculated according to the formula (1). θb=(δ / r)×(90 / π) …(2)

[0040] After calculating the rotation angle θb, the processor 21 stops the pick roller 41 and simultaneously rotates the brake roller 42 in the reverse direction by the rotation angle θb, as shown in FIG. 12. That is, the scanner 1 has a rotation mode (hereinafter sometimes referred to as a "second rotation mode") in which the pick roller 41 is stopped and simultaneously the brake roller 42 is rotated in the clockwise direction. The processor 21 also determines the rotation angle θb of the brake roller 42 in the second rotation mode according to the deviation amount δ. In this way, the brake roller 42 rotates in the reverse direction by the rotation angle θb with the pick roller 41 stopped, whereby the document deviation occurring between the upper side paper D1A and the lower side paper D1B is corrected as shown in FIG. 12 and FIG. 13.

[0041] After correcting the document misalignment by executing the second rotation mode using the rotation angle θb, the processor 21 rotates the pick roller 41 forward and rotates the brake roller 42 backward, as shown in Fig. 14 and Fig. 15. That is, the scanner 1 has a rotation mode (hereinafter sometimes referred to as "third rotation mode") in which the pick roller 41 rotates counterclockwise and the brake roller 42 rotates clockwise. In this way, the brake roller 42 rotates backward while the pick roller 41 rotates forward, so that the lower paper D1B is transported in the transport direction CD and the upper paper D1A is also transported in the transport direction CD at the same time. Therefore, the document D1 after the document misalignment is corrected does not experience a recurrence of the document misalignment due to the forward rotation of the brake roller 42, and the document D1 is transported in the transport direction CD.

[0042] <Processing procedure in the scanner> Fig. 16 is a flowchart showing an example of a processing procedure in the scanner according to the first embodiment of the present disclosure. The flowchart in Fig. 16 is started when a "scan start button" (not shown) of the scanner 1 is pressed with the document D placed on the paper feed tray 11.

[0043] In FIG. 16, in step S100, the processor 21 starts the execution of the first rotation mode, and causes both the pick roller 41 and the brake roller 42 to start rotating in the forward direction.

[0044] Next, in step S105, the processor 21 determines whether the amount of rotation of the pick roller 41 in the forward direction from the time when the scan start button is pressed (hereinafter, sometimes referred to as the "pick roller rotation amount") has reached a threshold value THP1. A motor (hereinafter, sometimes referred to as the "pick roller motor") (not shown) that rotates the pick roller 41 rotates by continuously giving motor pulses from the processor 21. In addition, since the amount of rotation of the pick roller motor per one motor pulse is constant, the amount of rotation of the pick roller 41 that rotates with the rotation of the pick roller motor per one motor pulse is also constant. Therefore, the processor 21 can calculate the amount of rotation of the pick roller by counting the number of motor pulses given to the pick roller motor from the time when the scan start button is pressed. If the amount of rotation of the pick roller has reached the threshold value THP1 (step S105: Yes), the process proceeds to step S110, and if the amount of rotation of the pick roller is less than the threshold value THP1 (step S105: No), the process returns to step S100. That is, while the amount of rotation of the pick roller after the scan start button is pressed is less than the threshold value THP1 (step S105: No), the processor 21 continues the execution of the first rotation mode and continues the forward rotation of both the pick roller 41 and the brake roller 42 (step S100). Note that the amount of rotation of the pick roller required for the leading edge of the document D transported from the paper feed tray 11 to the transport path P to be present within a range in which the area sensor 31 can capture an image of the leading edge of the document D in the transport direction CD is stored in advance in the memory 22 as the threshold value THP1.

[0045] In step S110, the processor 21 stops the pick roller 41 and the brake roller 42 once.

[0046] Next, in step S115, the processor 21 causes the area sensor 31 to capture an image of the vicinity of the leading edge of the document being conveyed in the conveying direction CD.

[0047] Next, in step S120, the processor 21 determines whether the document being transported is a document folded in half based on the captured image. For example, when the deviation angle θ in the captured image is equal to or greater than the threshold value THA, the processor 21 determines that the document being transported is a document folded in half, and when the deviation angle θ is less than the threshold value THA, the processor 21 determines that the document being transported is a document not folded in half. The threshold value THA is stored in advance in the memory 22, and is, for example, THA=5°. When the document being transported is determined to be a document folded in half (step S120: Yes), the process proceeds to step S125, and when the document being transported is determined to be a document not folded (step S120: No), the process proceeds to step S140.

[0048] In step S125, the processor 21 calculates the rotation angle θb of the reverse rotation of the brake roller 42 based on the deviation angle θ.

[0049] Next, in step S130, the processor 21 rotates the brake roller 42 in the reverse direction by the rotation angle θb while keeping the pick roller 41 stopped. That is, in step S130, the processor 21 executes the second rotation mode by using the rotation angle θb calculated based on the deviation angle θ.

[0050] Next, in step S135, the processor 21 rotates the pick roller 41 forward and rotates the brake roller 42 backward. That is, in step S135, the processor 21 executes the third rotation mode.

[0051] On the other hand, in step S140, processor 21 starts the forward rotation of both pick roller 41 and brake roller 42. That is, in step S140, processor 21 executes the first rotation mode. That is, when processor 21 determines that the document being transported is an unfolded document, processor 21 executes the first rotation mode without executing the second rotation mode.

[0052] The first embodiment has been described above.

[0053] [Example 2] In the second embodiment, the processor 21 does not calculate the rotation angle θb used in the second rotation mode, and in the second rotation mode, rotates the brake roller 42 in the reverse direction by a predetermined rotation angle θd.

[0054] <Processing procedure in the scanner> Fig. 17 is a flowchart showing an example of a processing procedure in the scanner according to the second embodiment of the present disclosure. Hereinafter, the flowchart in Fig. 17 will be described with respect to points different from the processing procedure in the first embodiment.

[0055] If it is determined that the document being conveyed is a folded document (step S120: Yes), the process proceeds to step S200. If it is determined that the document being conveyed is an unfolded document (step S120: No), the process proceeds to step S140.

[0056] In step S200, the processor 21 rotates the brake roller 42 in the reverse direction by a predetermined rotation angle θd while keeping the pick roller 41 stopped. That is, in step S200, the processor 21 executes the second rotation mode by using the predetermined rotation angle θd. The predetermined rotation angle θd is stored in the memory 22 in advance.

[0057] Next, in step S205, the processor 21 determines whether the deviation angle θ has reached a value less than the threshold value THG. The threshold value THG is a value less than the threshold value THA, for example, THG=5°. The threshold value THG is stored in advance in the memory 22. When the deviation angle θ is less than the threshold value THG (step S205: Yes), the process proceeds to step S135, and when the deviation angle θ is not less than the threshold value THG (step S205: No), the process returns to step S200. That is, while the deviation angle θ is equal to or greater than the threshold value THG (step S205: No), the processor 21 continues the execution of the second rotation mode using a predetermined rotation angle θd, and ends the execution of the second rotation mode when the deviation angle θ becomes less than the threshold value THG (step S205: Yes).

[0058] In this manner, when the processor 21 determines that the document being conveyed is a document folded in half, it continues to execute the second rotation mode until the deviation angle θ becomes less than the threshold value THG.

[0059] The second embodiment has been described above.

[0060] [Example 3] <Scanner configuration> 18 and 19 are diagrams showing a configuration example of a scanner according to a third embodiment of the present disclosure. The scanner 2 shown in Figs. 18 and 19 is a trade-in type device.

[0061] 18 and 19, the scanner 2 has a first ultrasonic sensor 24A and a second ultrasonic sensor 24B in addition to the configuration of the scanner 1 (FIG. 1). The first ultrasonic sensor 24A has a transmitter 24TA and a receiver 24RA, and the second ultrasonic sensor 24B has a transmitter 24TB and a receiver 24RB. The transmitter 24TA and the receiver 24RA are arranged opposite each other, and the transmitter 24TB and the receiver 24RB are arranged opposite each other. Hereinafter, the first ultrasonic sensor 24A and the second ultrasonic sensor 24B may be collectively referred to as "ultrasonic sensor 24", the transmitters 24TA and 24TB may be collectively referred to as "transmitter 24T", and the receivers 24RA and 24RB may be collectively referred to as "receiver 24R".

[0062] In the ultrasonic sensor 24, the ultrasonic waves transmitted from the transmitter 24T are received by the receiver 24R. When the reception level of the ultrasonic waves received by the receiver 24R (hereinafter sometimes referred to as the "ultrasonic reception level") is equal to or higher than a threshold TH1, the ultrasonic sensor 24 is turned on, whereas when the ultrasonic reception level is less than the threshold TH1, the ultrasonic sensor 24 is turned off.

[0063] When no document is present between the transmitter 24T and the receiver 24R, the ultrasonic reception level becomes equal to or greater than the threshold TH1, and the ultrasonic sensor 24 turns on. Even if a document is present between the transmitter 24T and the receiver 24R, when the thickness of the document (hereinafter sometimes referred to as the "target document") present between the transmitter 24T and the receiver 24R is equal to the thickness of one document D, the ultrasonic reception level becomes equal to or greater than the threshold TH1, and the ultrasonic sensor 24 turns on. When the document D is present between the transmitter 24T and the receiver 24R and the thickness of the target document is equal to or greater than two documents D, the ultrasonic reception level becomes less than the threshold TH1, and the ultrasonic sensor 24 turns off. In other words, the ultrasonic sensor 24 reacts when the thickness of the document being conveyed as the target document is less than the thickness of two documents D, but does not react when the thickness of the document being conveyed as the target document is equal to or greater than two documents D.

[0064] Note that a transmission-type optical sensor having a light projector and a light receiver may be used instead of the ultrasonic sensor 24. In the transmission-type optical sensor, light transmitted (projected) from the light projector is received (received) by the light receiver. When the reception level of the light received by the light receiver (hereinafter sometimes referred to as the "light reception level") is equal to or higher than the threshold value TH2, the transmission-type optical sensor is turned on, whereas when the light reception level is less than the threshold value TH2, the transmission-type optical sensor is turned off. Therefore, even if a transmission-type optical sensor is used instead of the ultrasonic sensor 24, it is possible to detect whether or not the transmission-type optical sensor reacts depending on the thickness of the document present between the light projector and the light receiver, similar to the ultrasonic sensor 24.

[0065] 19, the first ultrasonic sensor 24A and the second ultrasonic sensor 24B are arranged at an interval from each other in a direction perpendicular to the transport direction CD of the document being transported and along the width direction of the document being transported. For example, the first ultrasonic sensor 24A and the second ultrasonic sensor 24B are arranged near both ends of the document being transported in the width direction of the document being transported. The first ultrasonic sensor 24A and the second ultrasonic sensor 24B detect the thickness of the document being transported at different positions near the leading edge in the transport direction CD.

[0066] <Scanner operation> 20 and 21 are diagrams for explaining an operation example of the scanner according to the third embodiment of the present disclosure. Fig. 21 is a top view corresponding to the side view of Fig. 20.

[0067] Focusing on the upper side sheet D1A and the lower side sheet D1B forming the document D1, which is a document folded in half, document misalignment occurs between the lower side sheet D1B and the upper side sheet D1A, as in the first embodiment, as shown in Fig. 20 and 21. Therefore, as shown in Fig. 21, since both the upper side sheet D1A and the lower side sheet D1B are present between the wave transmitter 24TA and the wave receiver 24RA, the thickness of the document present between the wave transmitter 24TA and the wave receiver 24RA is the thickness of two sheets of document D. On the other hand, since only the lower side sheet D1B is present between the wave transmitter 24TB and the wave receiver 24RB, the thickness of the document present between the wave transmitter 24TB and the wave receiver 24RB is the thickness of one sheet of document D. Therefore, when the document D1 being transported is in the state shown in FIG. 21, the second ultrasonic sensor 24B reacts while the first ultrasonic sensor 24A does not react, so the number of reactions of the ultrasonic sensor 24 (hereinafter sometimes referred to as the "sensor reaction number") is "1".

[0068] <Processing procedure in the scanner> Fig. 22 is a flowchart illustrating an example of a processing procedure in a scanner according to the third embodiment of the present disclosure. Hereinafter, the flowchart in Fig. 22 will be described with respect to differences from the processing procedure in the first embodiment.

[0069] In FIG. 22, in step S100, the processor 21 starts the execution of the first rotation mode, and causes both the pick roller 41 and the brake roller 42 to start rotating in the forward direction.

[0070] Next, in step S300, the processor 21 determines whether the ultrasonic sensor 24 is on or off, and obtains the number of sensor responses.

[0071] Next, in step S305, the processor 21 determines whether the sensor response number acquired in step S300 is "2". When both the first ultrasonic sensor 24A and the second ultrasonic sensor 24B are turned on, the sensor response number becomes "2". Therefore, when the sensor response number becomes "2", the thickness of the target document at the first ultrasonic sensor 24A is the thickness of one document D, and the thickness of the target document at the second ultrasonic sensor 24B is the thickness of one document D. In other words, when the sensor response number becomes "2", one unfolded document is being conveyed. Therefore, when the sensor response number is "2" (step S305: Yes), the processing procedure ends while the first rotation mode is continued. On the other hand, when the sensor response number is "1" or less (step S305: No), the processing proceeds to step S310.

[0072] In step S310, the processor 21 continues the execution of the first rotation mode, and continues to rotate both the pick roller 41 and the brake roller 42 in the forward direction.

[0073] Next, in step S105, the processor 21 determines whether the rotation amount of the pick roller reaches the threshold THP1. If the rotation amount of the pick roller reaches the threshold THP1 (step S105: Yes), the process proceeds to step S110, and if the rotation amount of the pick roller is less than the threshold THP1 (step S105: No), the process returns to step S300.

[0074] In step S110, the processor 21 stops the pick roller 41 and the brake roller 42 once.

[0075] Next, in step S315, the processor 21 determines whether the number of sensor responses acquired in step S300 is "1".

[0076] Since the sensor response number becomes "1" when only either the first ultrasonic sensor 24A or the second ultrasonic sensor 24B is turned on, the sensor response number becomes "1" when the thickness of the target document at one of the ultrasonic sensors 24, the first ultrasonic sensor 24A or the second ultrasonic sensor 24B, is the thickness of one document D, and the thickness of the target document at the other ultrasonic sensor 24 is the thickness of two or more documents D. In other words, when the sensor response number becomes "1", a folded document in which a document misalignment has occurred is the document being transported.

[0077] On the other hand, since the sensor response number becomes "0" when both the first ultrasonic sensor 24A and the second ultrasonic sensor 24B are off, the sensor response number becomes "0" when the thickness of the target document at the first ultrasonic sensor 24A is equal to or greater than the thickness of two sheets of document D, and the thickness of the target document at the second ultrasonic sensor 24B is equal to or greater than the thickness of two sheets of document D. In other words, when the sensor response number becomes "0", two or more unfolded documents are being transported overlapping each other (i.e., double feeding is occurring).

[0078] That is, in step S315, processor 21 determines whether the document being transported is a document folded in half based on the number of sensor responses. If the number of sensor responses is "1" and it is determined that the document being transported is a document folded in half (step S315: Yes), the process proceeds to step S115, and if the number of sensor responses is "0" and it is determined that the document being transported is an unfolded document (step S315: No), the process proceeds to step S320. If the number of sensor responses is "0", processor 21 determines that a double feed of an unfolded document has occurred.

[0079] In step S115, the processor 21 causes the area sensor 31 to capture an image of the leading edge of the document in the conveying direction CD.

[0080] Next, in step S125, the processor 21 calculates the rotation angle θb of the reverse rotation of the brake roller 42 based on the deviation angle θ.

[0081] Next, in step S130, the processor 21 rotates the brake roller 42 in the reverse direction by the rotation angle θb while keeping the pick roller 41 stopped. That is, in step S130, the processor 21 executes the second rotation mode by using the rotation angle θb calculated based on the deviation angle θ.

[0082] Next, in step S135, the processor 21 rotates the pick roller 41 forward and rotates the brake roller 42 backward. That is, in step S135, the processor 21 executes the third rotation mode.

[0083] On the other hand, in step S320, the processor 21 causes the display 28 to display an error message to inform the user that a multi-feed has occurred in the unfolded document. For example, the processor 21 causes the display 28 to display an error message saying "A multi-feed has occurred in the document."

[0084] The third embodiment has been described above.

[0085] [Example 4] <Scanner configuration> 23 and 24 are diagrams showing a configuration example of a scanner according to a fourth embodiment of the present disclosure. The scanner 3 shown in Figs. 23 and 24 is a trade-in type device.

[0086] 23 and 24, the scanner 3 further includes a flap 51 in addition to the configuration of the scanner 1 (FIG. 1). The flap 51 is disposed in the transport path P between the pick roller 41 and the transport roller 26. The width of the flap 51 is approximately equal to the width of the transport path P, and is preferably longer than the width of the document being transported. The fulcrum of the flap 51 (hereinafter sometimes referred to as the "flap fulcrum") is located at the rear end of the flap 51 and is formed in the upper housing 13. The flap 51 has a mechanism for locking the flap 51, and is rotatable around the flap fulcrum when unlocked. The flap 51 is switched between locked and unlocked by the processor 21. The flap 51 is locked with the tip of the flap 51 lowered toward the lower housing 12, and the position of the flap 51 when the transport path P is blocked by the flap 51 is the initial position of the flap 51.

[0087] <Scanner operation> 25 to 30 are diagrams for explaining an operation example of the scanner according to the fourth embodiment of the present disclosure. Figs. 25, 27, and 29 are side views showing the state of a document that changes over time, Fig. 26 is a top view corresponding to the side view of Fig. 25, Fig. 28 is a top view corresponding to the side view of Fig. 27, and Fig. 30 is a top view corresponding to the side view of Fig. 29. As shown in Figs. 25, 27, and 29, a flap 51 has a flap fulcrum 52.

[0088] Focusing on the upper sheet D1A and the lower sheet D1B that form the document D1, which is a document folded in half, document misalignment occurs between the lower sheet D1B and the upper sheet D1A as shown in Figures 25 and 26, similar to the first embodiment. When the document D1 is in the state shown in Figures 25 and 26, the flap 51 is locked.

[0089] 27, the flap 51 is also locked when the processor 21 stops the pick roller 41 and simultaneously rotates the brake roller 42 in the reverse direction by the rotation angle θb. Therefore, during execution of the second rotation mode, the flap 51 collides with the leading edge of the document D1, which is a document folded in half, in the conveying direction CD, thereby suppressing the conveyance of the document D1 in the conveying direction CD. As a result, the conveyance of the upper side sheet D1A in the conveying direction CD and the conveyance of the lower side sheet D1B in the conveying direction CD are suppressed until the document misalignment that occurs between the upper side sheet D1A and the lower side sheet D1B is corrected as shown in FIGS. 27 and 28. The flap 51 is an example of a "suppression unit" that suppresses the conveyance of the document folded in half in the conveying direction CD by colliding with the leading edge of the document folded in half in the conveying direction CD.

[0090] Then, after correcting the document misalignment by executing the second rotation mode using the rotation angle θb, the processor 21 unlocks the flap 51, rotates the pick roller 41 forward, and simultaneously rotates the brake roller 42 reversely, as shown in Figures 29 and 30. In this way, by rotating the brake roller 42 reversely while the pick roller 41 is rotating forward, the lower sheet D1B is transported in the transport direction CD and the upper sheet D1A is also transported in the transport direction CD at the same time, so that the document D1 after the document misalignment has been corrected is transported in the transport direction CD. Also, by unlocking the flap 51, the flap 51 rotates rightward (clockwise) about the flap fulcrum 52 in association with the transport of the document D1 in the transport direction CD, so that the transport of the document D1 is not impeded.

[0091] <Processing procedure in the scanner> Fig. 31 is a flowchart showing an example of a processing procedure in a scanner according to the fourth embodiment of the present disclosure. Hereinafter, the flowchart in Fig. 31 will be described with respect to differences from the processing procedure in the first embodiment.

[0092] 31, in step S400, the processor 21 locks the flap 51 in a state in which the flap 51 blocks the conveying path P. After the process of step S400, the process proceeds to step S100.

[0093] If it is determined that the document being conveyed is a folded document (step S120: Yes), the process proceeds to step S125. If it is determined that the document being conveyed is an unfolded document (step S120: No), the process proceeds to step S410.

[0094] After the processes of steps S125 and S130, the process proceeds to step S405, where the processor 21 unlocks the flap 51. That is, when the processor 21 determines that the document being transported is a document folded in half, the processor 21 locks the flap 51 during execution of the second rotation mode, and unlocks the flap 51 after the execution of the second rotation mode is completed. After the process of step S405, the process proceeds to step S135, where the third rotation mode is executed. In this way, the processor 21 enables the inhibition of the transport of the document being transported by the flap 51 during execution of the second rotation mode, while canceling the inhibition of the transport of the document being transported by the flap 51 during execution of the third rotation mode.

[0095] On the other hand, in step S410, the processor 21 unlocks the flap 51. After the process of step S410, the process proceeds to step S140. That is, when the processor 21 determines that the document being conveyed is an unfolded document, the processor 21 unlocks the flap 51 without executing the second rotation mode, and then executes the first rotation mode.

[0096] The fourth embodiment has been described above.

[0097] [Example 5] <Scanner configuration> 32 and 33 are diagrams illustrating a configuration example of a scanner according to a fifth embodiment of the present disclosure. The scanner 4 illustrated in Figs. 32 and 33 is a trade-in type device.

[0098] 32 and 33, the scanner 4 further includes a first ultrasonic sensor 24A, a second ultrasonic sensor 24B, and a flap 51 in addition to the components of the scanner 1 (FIG. 1).

[0099] <Processing procedure in the scanner> Fig. 34 is a flowchart showing an example of a processing procedure in the scanner according to the fifth embodiment of the present disclosure. Hereinafter, the flowchart in Fig. 34 will be described with respect to differences from the processing procedures in the first, third, and fourth embodiments.

[0100] In FIG. 34, the processor 21 unlocks the flap 51 in step S500.

[0101] Next, in step S100, the processor 21 starts the execution of the first rotation mode, and starts the forward rotation of both the pick roller 41 and the brake roller 42. After the process of step S100, the process proceeds to step S300.

[0102] After the process of step S125, the process proceeds to step S505, where the processor 21 locks the flap 51 in a state where the flap 51 blocks the conveying path P.

[0103] Next, in step S130, the processor 21 executes the second rotation mode by using the rotation angle θb calculated based on the deviation angle θ.

[0104] Next, in step S510, the processor 21 unlocks the flap 51. That is, when the processor 21 determines that the document being transported is a document folded in half (step S315: Yes), the processor 21 locks the flap 51 during execution of the second rotation mode, and unlocks the flap 51 after execution of the second rotation mode ends. After the process of step S510, the process proceeds to step S135.

[0105] The fifth embodiment has been described above.

[0106] It is also possible to combine the second embodiment with the third and fourth embodiments.

[0107] [Example 6] <Scanner configuration> 35 and 36 are diagrams illustrating configuration examples of a scanner according to a sixth embodiment of the present disclosure. Configuration examples 1 and 2 will be described below.

[0108] <Configuration example 1 (Fig. 35)> As shown in FIG. 35, the scanners 1 to 4 may have a member 61 that narrows the vertical width of the document insertion slot .

[0109] <Configuration example 2 (Fig. 36)> As shown in FIG. 36, the scanners 1 to 4 may have a pad 62 that applies a transport load to the document during transport.

[0110] By having the scanners 1 to 4 have the member 61 or the pad 62, when the second rotation mode is executed on the folded original, the document next to the folded original can be prevented from being pulled by the upper sheet of the folded original into the conveying path P.

[0111] The sixth embodiment has been described above.

[0112] In the first to sixth embodiments, the disclosed technology is applied to a trade-in type device as an example, but the disclosed technology can be applied not only to a trade-in type device but also to a top-up type device.

[0113] As described above, the image reading device (scanners 1, 2, 3, and 4 in the embodiment) of the present disclosure includes a tray (paper feed tray 11 in the embodiment) on which a document is placed, a transport path (transport path P in the embodiment) through which the document is transported, an image sensor (image sensor 17 in the embodiment), a pair of rollers, a first roller (pick roller 41 in the embodiment) and a second roller (brake roller 42 in the embodiment), which transport the document from the tray to the transport path, and a processor (processor 21 in the embodiment). The image sensor reads an image of the document being transported on the transport path. The first roller and the second roller are disposed opposite each other with the document sandwiched between them. The processor executes a first rotation mode in which the outermost document on the first roller side among the multiple documents placed on the tray can be separated from the multiple documents by rotating the first roller in a first direction (counterclockwise direction in the embodiment) and simultaneously rotating the second roller in the first direction. In addition, after executing the first rotation mode, the processor determines whether the document being transported, which is the document being transported from the tray to the transport path, is a double-folded document, which is a document that has been folded in half. When the processor determines that the document being conveyed is a document folded in half, the processor executes a second rotation mode in which the processor stops the first roller and rotates the second roller in a second direction (clockwise direction in the embodiment) opposite to the first direction. After executing the second rotation mode, the processor executes a third rotation mode in which the processor rotates the first roller in the first direction and rotates the second roller in the second direction at the same time.

[0114] In this way, the document misalignment of the double-folded document is corrected, and the double-folded document can be transported without the document misalignment caused by the rotation of the second roller in the first direction reoccurring after the document misalignment has been corrected, thereby preventing the double-folded document from jamming.

[0115] For example, when the processor determines that the document being conveyed is a document folded in half, it determines the rotation angle of the second roller in the second rotation mode according to the angle of deviation.

[0116] In this way, the misalignment of the document folded in half can be accurately corrected.

[0117] Also, for example, when the processor determines that the document being conveyed is a document folded in half, it continues to execute the second rotation mode until the magnitude of the angle of deviation becomes less than the threshold value.

[0118] In this way, the misalignment of the document folded in half can be corrected without excess or deficiency.

[0119] In addition, the processor determines that the document being transported is a folded document when there is an angle deviation of a threshold value or more between the paper in contact with the first roller and the paper in contact with the second roller.

[0120] In this way, it is possible to accurately determine whether the document being conveyed is a folded document or not.

[0121] The image reading device of the present disclosure also includes an image capturing unit (area sensor 31 in the embodiment) that captures an image of the leading edge of the document in the transport direction during the first rotation mode. The processor determines whether the document is a folded document based on the image captured by the image capturing unit.

[0122] This makes it easy to determine whether the document being conveyed is a folded document or not.

[0123] The image reading device of the present disclosure also has a first sensor (one of the first ultrasonic sensor 24A and the second ultrasonic sensor 24B in the embodiment) and a second sensor (the other of the first ultrasonic sensor 24A and the second ultrasonic sensor 24B in the embodiment) that are arranged at an interval in a direction perpendicular to the transport direction of the document being transported and along the width direction of the document being transported. The first sensor and the second sensor detect the thickness of the document being transported at different positions near the leading edge in the transport direction of the document being transported while the first rotation mode is being executed. The processor determines that the document being transported is a document folded in half when the thickness detected by the first sensor is equal to or greater than the thickness of two documents and the thickness detected by the second sensor is less than the thickness of two documents.

[0124] By doing so, it is possible to determine whether the document being transported is a folded document in a shorter time than in the case where it is determined whether the document being transported is a folded document based on an image captured by the photographing section.

[0125] The image reading device of the present disclosure also has a suppression unit (flap 51 in the embodiment) that suppresses the transport of the folded document in the transport direction by colliding with the leading edge of the folded document in the transport direction. The processor enables the suppression of the transport of the folded document by the suppression unit while the second rotation mode is being executed, and releases the suppression of the transport of the folded document by the suppression unit while the third rotation mode is being executed.

[0126] This makes it possible to suppress misalignment of the folded document due to inertial force or impact generated in the folded document when the document misalignment is corrected, thereby preventing skew when reading an image of the folded document. Also, it is possible to prevent the suppression unit from interfering with the conveyance of the folded document after the document misalignment has been corrected. [Explanation of symbols]

[0127] 1,2,3,4 Scanner 11 Paper feed tray 17 Image Sensor 21 Processors 41 Pick roller 42 Brake roller 24 Ultrasonic Sensor 31 Area Sensor 51 Flap P Transport path

Claims

1. A tray on which documents are placed; a conveying path along which the document is conveyed; a pair of rollers for transporting the document from the tray to the transport path, the pair of rollers being a first roller and a second roller arranged opposite to each other with the document sandwiched therebetween; a first rotation mode in which the first roller is rotated in a first direction and the second roller is rotated in the first direction at the same time, so that an outermost document on a side of the first roller among a plurality of documents placed on the tray can be separated from the plurality of documents; a second rotation mode in which, when a document being transported from the tray to the transport path is a document that has been folded in half after the first rotation mode is executed, the first roller is stopped and the second roller is rotated in a second direction opposite to the first direction; a processor for switching between a third rotation mode in which the first roller is rotated in the first direction and the second roller is rotated in the second direction at the same time after the second rotation mode is executed; and A document transport device comprising:

2. the processor determines that the document being transported is the document folded in half when there is an angle of a threshold value or more between the sheet of the document being transported that is in contact with the first roller and the sheet of the document being transported that is in contact with the second roller. The document transport device according to claim 1 .

3. when the processor determines that the document being conveyed is the document folded in half, the processor determines a rotation angle of the second roller in the second rotation mode in accordance with the angle of the deviation. The document transport device according to claim 2 .

4. when the processor determines that the document being conveyed is the document folded in half, the processor continues to execute the second rotation mode until the magnitude of the angle of the deviation becomes less than a threshold value. The document transport device according to claim 2 .

5. a photographing unit that photographs an image of a portion of the document in a conveying direction of the document during the first rotation mode; the processor determines whether the document being transported is the document folded in half based on the image. The document transport device according to claim 1 .

6. a first sensor and a second sensor arranged at an interval in a direction perpendicular to the transport direction of the document being transported and along a width direction of the document being transported, the first sensor and the second sensor detecting thicknesses of the document being transported at different positions near a leading edge of the document in the transport direction while the first rotation mode is being executed; the processor determines that the document being conveyed is the document folded in half when the thickness detected by the first sensor is equal to or greater than the thickness of two documents and the thickness detected by the second sensor is less than the thickness of two documents. The document transport device according to claim 1 .

7. a suppression unit that suppresses conveyance of the folded document in the conveyance direction by colliding with a leading end of the folded document in the conveyance direction, The processor enables the suppression of the conveyance by the suppression unit while the second rotation mode is being executed, and releases the suppression of the conveyance by the suppression unit while the third rotation mode is being executed. The document transport device according to claim 1 .

8. A tray on which documents are placed; a conveying path along which the document is conveyed; a pair of rollers for transporting the document from the tray to the transport path, the pair of rollers being a first roller and a second roller arranged opposite to each other with the document sandwiched therebetween; A roller control method for a document transport device comprising: a first rotation mode in which the first roller is rotated in a first direction and the second roller is rotated in the first direction at the same time, so that an outermost document on a side of the first roller among a plurality of documents placed on the tray can be separated from the plurality of documents; a second rotation mode in which, when a document being transported from the tray to the transport path is a document that has been folded in half after the first rotation mode is executed, the first roller is stopped and the second roller is rotated in a second direction opposite to the first direction; After the second rotation mode is executed, switching is made to a third rotation mode in which the first roller is rotated in the first direction and the second roller is rotated in the second direction at the same time. Roller control method.

Images