JP2024042260A - Sheet transport device, image reading device, image forming device - Google Patents

Abstract

[Problem] To provide a sheet transport device capable of reducing false detection of abnormal transport of a document, and an image reading device and an image forming device equipped with the same. [Solution] The image reading device 100 includes a document tray 105 on which documents are loaded, a pickup roller 107 that transports the documents from the document tray, a document separation section 150 that separates and transports the documents transported by the pickup roller one by one, a tracking sensor 111 that detects the speed of the transported documents, and a CPU 202 that controls the driving of the document separation section 150. The CPU 202 continues feeding of the document if the speed in the width direction of the document becomes equal to or lower than a second speed during the time period from when the speed in the width direction of the document becomes equal to or higher than a first speed until a predetermined time has elapsed. [Selected Figure] Figure 12

Description

The present invention relates to a sheet conveying device that conveys sheets, an image reading device, and an image forming device equipped with the same.

2. Description of the Related Art Conventionally, image forming apparatuses such as copying machines are known that are equipped with an image reading device that reads an image of a document. Some image reading devices are capable of reading images while conveying a document using an automatic document feeder (hereinafter referred to as ADF). An ADF that separates original documents one by one cannot transport originals bound with staples or the like, and if such an abnormal original is set on the original tray, it is desirable to stop the transport. Patent Document 1 discloses an image reading device that detects an abnormal document using a tracking sensor that detects the amount of movement (velocity) of the document per predetermined time.

JP 2019-26393 Publication

By the way, when a user sets a document on a document tray, the center of the document in the width direction may be offset from the center of the document tray. When the ADF starts transporting the original in such a state, the original may rotate with respect to the transport direction when the original starts moving from a stopped state. As a result, the tracking sensor may erroneously detect that a stapled document has been transported.

The present invention aims to provide a sheet transport device that can reduce false detection of abnormal document transport, as well as an image reading device and an image forming device that are equipped with the same.

One aspect of the present invention provides a stacking means on which sheets are stacked, a separation feeding means for separating and feeding the sheets stacked on the stacking means one by one, and a separation feeding means for separating and feeding the sheets one by one, which are fed by the separation feeding means. A speed detection means for detecting the speed of the sheet, and a control means for controlling the separation and feeding means, and the control means has a width perpendicular to the sheet feeding direction detected by the speed detection means. If the speed in the width direction of the sheet does not become equal to or less than the second speed smaller than the first speed until a predetermined time elapses after the speed in the direction becomes equal to or higher than the first speed, the separation is performed. During the period from when the sheet feeding means stops feeding the sheet and the speed of the sheet in the width direction detected by the speed detecting means becomes equal to or higher than the first speed, until the predetermined time elapses, The sheet conveying device is characterized in that when the speed in the width direction of the sheet becomes equal to or lower than the second speed, the separation and feeding means continues to feed the sheet.

According to the present invention, it is possible to provide a sheet conveyance device that can reduce false detection of abnormal conveyance of a document, and an image reading device and an image forming device equipped with the same.

FIG. A block diagram of a control unit. FIG. 3 is a cross-sectional view of a tracking sensor that detects the amount of movement of a document. FIG. 3 is a plan view showing the operation of conveying a document by a pickup roller and a document separation unit. FIG. 3 is a diagram illustrating image data indicating a document position acquired by a tracking sensor. 6 is a diagram showing a transition of an output value of a tracking sensor during normal document transport. FIG. 3 is a diagram showing a stapled document bundle. 4 is a plan view showing the transport operation of a document stack by a pickup roller and a document separating section; FIG. 11A and 11B are diagrams showing transition of an output value of a tracking sensor during transport of a stapled document stack. FIG. 3 is a plan view showing the operation of conveying a document by a pickup roller and a document separation unit. FIG. 6 is a diagram showing changes in the output value of a tracking sensor during transportation of a rough set document bundle. 5 is a flowchart showing a stop control operation for stopping abnormal conveyance.

(Image forming device)
First, an image forming apparatus 1 that forms an image on a recording medium (hereinafter referred to as a sheet) will be described with reference to FIG. FIG. 1 is a cross-sectional view of the image forming apparatus 1. As shown in FIG. The image forming apparatus 1 includes an image forming apparatus main body 10 and an image reading device 100 provided on the upper part of the image forming apparatus main body 10. The image forming apparatus main body 10 includes a cassette 11 that stores sheets, an image forming section 12 that forms an image on the sheet conveyed from the cassette 11, and a discharge tray 13 that discharges the sheet on which the image has been formed. The image forming section 12 as an image forming means is configured as an electrophotographic print engine, and includes a laser writing section, an electrophotographic processing section, a fixing section, etc. (not shown). The image forming apparatus main body 10 includes a built-in feeding roller (not shown) that separates and feeds the sheets placed in the cassette 11 one by one, and supplies the sheets to the image forming section 12. Note that the image forming unit 12 in this embodiment is configured as a print engine using an electrophotographic method, but may be formed using another method such as an inkjet method.

The image reading device 100 includes a reader 101 that reads an image of a document, and an ADF 103 as a sheet transport device that transports sheets that are documents. The ADF 103 is provided with an opening/closing cover 102. If a jam occurs during document transport, the user can open the opening/closing cover 102 to remove the document 104. The document 104 is loaded on a document tray 105 that serves as a loading means. The ADF 103 includes a pickup roller 107 that feeds the document, and a document separation section 150 (sheet separation section) that is composed of a feed roller 109 and a separation roller 110. The pickup roller 107 and the document separation section 150 are an example of a separation and feeding means.

The original 104 placed on the original tray 105 is fed to the original separating section 150 by the pickup roller 107. As shown in FIG. 1, a separation pad 134 is arranged in the ADF 103 so as to face the pickup roller 107. Separation pad 134 prevents documents 104 from being bundled and fed to document separation section 150 . A pre-separation sensor 108 serving as a sheet detection unit detects that the original 104 has reached the original separation unit 150 . This is because, since the original 104 is transported at a predetermined transport speed, it is possible to predict that the leading edge of the original 104 will reach the original separation unit 150 after a predetermined time has elapsed after reaching the pre-separation sensor 108. In the document separating section 150, a feeding roller 109 and a separating roller 110 are arranged facing each other downstream of the pickup roller 107, forming a nip. The document separation unit 150 separates and conveys the document 104 one by one so as to prevent double feeding of the document 104 fed by the pickup roller 107 .

The pickup roller 107 feeds the top sheet of the stack of documents placed on the document tray 105 . A tracking sensor 111 serving as speed detection means is arranged between the pickup roller 107 and the document separating section 150. The original 104 fed by the pickup roller 107 is detected by a tracking sensor 111 that detects the amount of movement of the original in the feeding direction and the amount of movement of the original 104 in a direction perpendicular to the feeding direction. The tracking sensor 111 detects the moving amount (moving speed) of the document at predetermined time intervals at a detection position between the pickup roller 107 and the feeding roller 109 in the feeding direction. The tracking sensor 111 is a tracking sensor that detects the amount of movement of the surface of the document 104 by sampling, at a predetermined sampling period, an image obtained by having an image sensor receive reflected light when the surface of the document 104 is irradiated with laser light. It is a type of optical sensor. Note that the tracking sensor 111 outputs the amount of movement of the original 104 per predetermined time, but in this embodiment, outputting the amount of movement of the original 104 per predetermined time means detecting the speed. .

The pre-separation sensor 108 is provided on the conveyance path between the pickup roller 107 and the document separation section 150, and is disposed upstream of the tracking sensor 111 in the document feeding direction CD.

After the original 104 is transported by a first transport roller 112 and a second transport roller 113, the skew of the original 104 is corrected by a first registration roller 114 and a third transport roller 115. Thereafter, the document 104 is transported by the second registration roller 116 , the fourth transport roller 117 , the fifth transport roller 118 , and the sixth transport roller 119 . The transported original 104 is irradiated with light by light sources 125 and 126, and the reflected light is guided to an imaging lens 130 via a first mirror 127, a second mirror 128, and a third mirror 129. The guided light is converged by an imaging lens 130, and an image is formed on a line sensor 131 in which an imaging device such as a CCD is arranged on a line. The imaged optical signal is converted into an electric signal by the line sensor 131, and converted into a digital signal by the signal processing board 132, thereby obtaining image data. Thereafter, the document 104 is conveyed to the seventh conveyance roller 120 and the eighth conveyance roller 121, and is discharged onto the discharge tray 124 by the document discharge roller 122 and the ninth conveyance roller 123. Note that the reader 101 functions as a reading means in this embodiment, and the image forming unit 12 of the image forming apparatus main body 10 can form an image on a sheet based on the image of the document 104 read by the reader 101. be.

The width regulating plate 133 is movable in the width direction of the original 104, and the end of the original 104 is brought into contact with the width regulating plate 133 by the user so that the original 104 does not travel skewed when transport starts. It is set as follows.

FIG. 2 is a block diagram of the control unit 160. The control unit 160 includes a CPU 202 as a control means for controlling the image reading device 100. The CPU 202 is electrically connected to the operation unit 201, the document set detection sensor 106, the transport motor 203, the pre-separation sensor 108, the tracking sensor 111, the ROM 141, and the RAM 142. The document set detection sensor 106 is provided on the document tray 105 and detects whether a document is placed (set) on the document tray 105 or not. When the user presses a copy button provided on the operation unit 201, a reading start instruction (scan job start instruction) is output from the operation unit 201 to the CPU 202. The CPU 202 functions as a reception unit that receives a reading start instruction. The operation unit 201 has a display (not shown) and functions as a notification means for notifying the user of information.

When the CPU 202 receives the reading start instruction, the CPU 202 detects whether the original 104 is placed on the original tray 105 using the original set detection sensor 106 . When the original 104 is placed on the original tray 105, the CPU 202 causes the transport motor 203 to drive the pickup roller 107 to start transporting the original 104. When the document reaches the pre-separation sensor 108, the tracking sensor 111 starts sampling continuously at a predetermined period to detect the amount of movement of the document 104. Since the original 104 is transported at a predetermined transport speed, it is possible to predict that the leading edge of the original 104 will pass the tracking sensor 111 after a predetermined period of time has elapsed since the leading edge of the original 104 reached the pre-separation sensor 108. be. Therefore, after the pre-separation sensor 108 is turned on, the CPU 202 controls the sampling value of the tracking sensor 111 after a predetermined period of time is valid, and stops the sampling of the tracking sensor 111 after the predetermined period of time has elapsed.

Next, the relationship between paper conveyance control and the output signal of the tracking sensor 111 when a stack of unstapled originals is conveyed will be explained using FIG. FIG. 3 is a cross-sectional view of the tracking sensor 111 that detects the amount of movement of the document 104.

FIG. 3A is a diagram showing the positional relationship between the tracking sensor 111, the original 104, and the original 308 at time t1 before the original 104 reaches the original separation unit 150. The first document 104 and the second document 308 from the document bundle are conveyed from the pickup roller 107 and the separation pad 134 to the document separation section 150 in the feeding direction CD.

FIG. 3B is a diagram showing the positional relationship between the tracking sensor 111, the original 104, and the original 308 after the original 104 reaches the original separation unit 150 (time t2). The original 104 reaches the original separating unit 150 at time t2 (t1<t2). In FIG. 3B, an arrow 306 indicates the rotation direction of the feed roller 109, and an arrow 307 indicates the rotation direction of the separation roller 110. The feeding roller 109 rotates to convey the uppermost document 104 in the feeding direction CD. The separation roller 110 rotates so as to convey the document 308 below the uppermost document 104 in a direction that pushes it back upstream (a direction opposite to the feeding direction CD). As a result, the uppermost original 104 is separated from the second original 308, and only the uppermost original 104 is transported in the feeding direction CD.

The tracking sensor 111 has a laser emission unit 301, a collimator lens 302, an imaging lens 303, and a light receiving sensor 304. Coherent light 305 emitted from the laser emission unit 301 is irradiated onto the original 104 via the collimator lens 302. The light reflected by the original 104 is incident on the light receiving sensor 304 via the imaging lens 303. The light receiving sensor 304 has a plurality of pixels arranged two-dimensionally. The light receiving sensor 304 converts the amount of light incident on each pixel into an electrical signal (photoelectric conversion) and outputs image data.

FIG. 4 is a plan view showing the operation of conveying the original 104 by the pickup roller 107 and the original separation unit 150. FIG. 4(a) is a plan view of the document 104 in the position shown in FIG. 3(a). FIG. 4A shows the uppermost (first) document 104 and second document 308 that have been conveyed by the pickup roller 107 past the separation pad 134 and below the tracking sensor 111. Both sides of the original 104 and the original 308 are regulated by a width regulating plate 133 so as not to be skewed, and the original 104 and the original 308 are conveyed in the feeding direction CD by the pickup roller 107. FIG. 4(b) is a plan view when the document 104 is in the position shown in FIG. 3(b). When the original 104 and the original 308 are conveyed to the original separation unit 150, as shown in FIG. 4(b), the first original 104 is conveyed in the feeding direction CD by the feeding roller 109, and the second original The original 308 is left on the original tray 105 by the separation roller 110.

FIG. 5 is a diagram showing image data indicating the document position acquired by the tracking sensor 111. FIG. 5(a) is an example of image data of a speckle pattern acquired by the tracking sensor 111 when the document 104 is in the position shown in FIG. 4(a) (time t1). FIG. 5B is an example of speckle pattern image data acquired by the tracking sensor 111 when the document 104 is at the position shown in FIG. 4B (time t2, t1<t2). In this embodiment, as an example, the tracking sensor 111 acquires image data of 8 pixels x 8 pixels. The image data is obtained by converting the amount of light received by the light receiving sensor 304 in which a plurality of pixels are two-dimensionally arranged into a binary value. Black pixels indicate that the amount of received light is smaller than the binarization threshold. White pixels indicate that the amount of received light is equal to or greater than the binarization threshold.

Comparing FIG. 5(a) and FIG. 5(b), it can be seen that the black pixels shown in FIG. 5(b) are shifted in the feeding direction CD compared to FIG. 5(a). In FIGS. 5A and 5B, the original 104 is conveyed from right to left as indicated by the feeding direction CD. 5(a) and 5(b), while the original 104 moves from the position shown in FIG. 3(a) to the position shown in FIG. 3(b), 5 pixels of image data It can be seen that the position has moved in the feeding direction CD by the amount of time. The tracking sensor 111 acquires image data of a speckle pattern at predetermined time intervals. The tracking sensor 111 outputs the amount of movement of the black pixels of the image data in the feeding direction CD within a predetermined time interval as an output value (count value). Based on the output value (count value) output from the tracking sensor 111, the amount of movement (moving speed) of the document 104 in the feeding direction CD can be measured. Note that the tracking sensor 111 outputs the amount of movement of the document in a predetermined time, but in this embodiment, outputting the amount of movement of the document in a predetermined time is equivalent to detecting the speed of the document.

(Normal transport of original)
FIG. 6 is a diagram showing changes in the output value of the tracking sensor 111 during normal document transport. FIG. 6 shows the transition of the output value of the tracking sensor 111 when the document 104 is normally conveyed at a predetermined moving speed in the feeding direction CD. In FIG. 6, the horizontal axis represents time (milliseconds), and the vertical axis represents the output value (count value) of the tracking sensor 111. In this embodiment, the output value of the tracking sensor 111 represents the amount of movement of the black pixels of the image data in the feeding direction CD as a count value. FIG. 6 shows changes in the amount of movement 601 of the original 104 in the feeding direction CD and changes in the amount of movement 602 of the original 104 in the main scanning direction MS (width direction) perpendicular to the feeding direction CD. When the document 104 is normally conveyed at a predetermined moving speed, the movement amount 601 of the document 104 in the feeding direction CD remains at a constant value 2 milliseconds (ms) after the start of conveyance. In this embodiment, an example is shown in which the amount of movement of the document 104 in the feeding direction CD changes at approximately 6000 counts every 1 ms. On the other hand, since the original 104 hardly moves in the main scanning direction MS, the amount of movement 602 of the original 104 in the main scanning direction MS changes at a value close to zero.

(Transporting a stack of stapled originals)
Next, the relationship between the conveyance operation when the stapled document bundle 200 is conveyed and the output value of the tracking sensor 111 will be explained. FIG. 7 is a diagram showing a stapled document bundle 200. In this embodiment, as an example, as shown in FIG. 7, a document bundle 200 in which a document 104 and a document 308 are stapled at the upper left corner with a staple 701 is conveyed.

FIG. 8 is a plan view showing the operation of conveying the document bundle 200 by the pickup roller 107 and the document separating section 150. FIG. 8(a) shows a document bundle in which a first document 104 and a second document 308 are stapled together with staples 701, and the pickup roller 107 passes the separation pad 134 and is conveyed below the tracking sensor 111. 200. FIG. At this point, the first document 104 and the second document 308 bound with staples 701 are not sufficiently separated and are transported almost straight along the feeding direction CD.

FIG. 8B is a diagram showing the document bundle 200 conveyed to the document separation section 150. The first document 104 is conveyed in the feeding direction CD by the feeding roller 109, while the second document 308 is conveyed by the separating roller 110 in the opposite direction to the feeding direction CD. In this way, the document separation unit 150 attempts to separate the first document 104 and the second document 308. However, since the first original 104 and the second original 308 are stapled together by the staple 701, the first original 104 cannot move straight in the feeding direction CD but rotates. When the document stack 200 is further conveyed, the document stack 200 jams and the image reading device 100 is stopped.

FIG. 9 is a diagram showing changes in the output value of the tracking sensor 111 when the stapled document bundle 200 is conveyed. FIG. 9 shows a change in the output value of the tracking sensor 111 when the tracking sensor 111 detects the surface of the first document 104 of the stapled document bundle 200. In FIG. 9, the horizontal axis represents time (milliseconds), and the vertical axis represents the output value (count value) of the tracking sensor 111. FIG. 9 shows changes in the amount of movement 901 of the first original 104 in the feeding direction CD and changes in the amount of movement 902 of the first original 104 in the main scanning direction MS perpendicular to the feeding direction CD. There is.

As shown in FIG. 8A, when the document bundle 200 is conveyed by the pickup roller 107, passes the separation pad 134, and reaches the tracking sensor 111, the first document 104 is fed without turning. Go straight along direction CD. Therefore, immediately after the start of conveyance, the amount of movement 901 in the feeding direction CD increases, and the amount of movement 902 in the main scanning direction MS is small. Thereafter, as shown in FIG. 8B, when the first document 104 reaches the document separating section 150, the first document 104 is conveyed while gradually turning. As a result, the first document 104 also begins to move in the main scanning direction MS. Therefore, after a while from the start of conveyance, the amount of movement 901 in the feeding direction CD gradually decreases, and the amount of movement 902 in the main scanning direction MS gradually increases.

As shown in FIG. 9, the amount of movement 901 in the feeding direction CD gradually increases immediately after the start of conveyance, and then gradually decreases. On the other hand, the movement amount 902 in the main scanning direction MS remains close to zero immediately after the start of conveyance, and then gradually increases. Since the document bundle 200 is regulated in the width direction by the width regulating plate 133, the rotation of the first document 104 is suppressed after that, and the amount of movement 901 in the feeding direction CD and the amount of movement in the main scanning direction MS are reduced. 902, both gradually decrease.

(Transportation of rough set originals)
Next, the relationship between the conveyance operation when the roughly set document 104 is conveyed and the output value of the tracking sensor 111 will be described. Rough setting in this embodiment refers to a case where the user sets the original 104 on the original tray 105 without regulating the width in the width direction using the width regulating plate 133.

FIG. 10 is a plan view showing the operation of transporting the roughly set original 104 by the pickup roller 107 and the original separating unit 150. FIG. 10A is a diagram showing the document 104 that has been conveyed by the pickup roller 107 past the separation pad 134 and below the tracking sensor 111. As shown in FIG. 10A, if the width regulating plate 133 does not restrict the width of the original 104, it becomes difficult to set the original 104 in alignment with the center of the original tray 105. As a result, depending on how the user places the document 104, the document 104 may shift from the center of the document tray 105 in the main scanning direction MS. Since the pickup roller 107 is arranged at the center of the main scanning direction MS with respect to the document tray 105, the pickup roller 107 is transported while being in contact with the document 104 at a position offset from the main scanning center. becomes diagonal.

FIG. 10B is a diagram showing the original 104 conveyed to the original separating section 150. As shown in FIG. 10B, when the roughly set original 104 reaches the original separating unit 150, the original 104 is pulled and conveyed in the feeding direction CD by the feeding roller 109. As a result, the original 104 is prevented from being skewed and is transported straight in the feeding direction CD. In other words, the roughly set document 104 is conveyed while turning immediately after the pick-up roller 107 starts feeding, but after passing through the document separating section 150, the turning is suppressed by the nip of the document separating section 150, and the document 104 is conveyed while turning. conveyed along the

FIG. 11 is a diagram showing changes in the output value of the tracking sensor 111 when the rough set document 104 is transported. In FIG. 11, the horizontal axis represents time (milliseconds), and the vertical axis represents the output value (count value) of the tracking sensor 111. FIG. 11 shows changes in the amount of movement 1101 of the original 104 in the feeding direction CD and changes in the amount of movement 1102 of the original 104 in the main scanning direction MS perpendicular to the feeding direction CD.

As shown in FIG. 10A, since the document 104 is skewed (swiveled) immediately after the pickup roller 107 starts feeding, the amount of movement 1101 in the feeding direction CD and the amount of movement 1102 in the main scanning direction MS are both To increase. After that, as shown in FIG. 10(b), when the original 104 reaches the original separating unit 150, the original 104 is conveyed while being pulled in the feeding direction by the feeding roller 109, so that the original 104 is not skewed. Converge. As a result, as shown in FIG. 11, the amount of movement 1102 of the original 104 in the main scanning direction MS rapidly decreases.

As described above, when the stapled document bundle 200 is fed, since the first document 104 is held by the staple 701, the rotation of the first document 104 gradually stops. The amount of movement 902 in the main scanning direction MS gradually decreases. On the other hand, when the rough set original 104 is fed, the skew is suppressed when the original 104 reaches the original separation unit 150, so the movement amount 1102 in the main scanning direction MS tends to decrease significantly. be. Therefore, it is possible to distinguish between the stapled document bundle 200 and the roughly set document 104 based on the speed at which the movement amount decreases in the main scanning direction MS. Therefore, in the present embodiment, the CPU 202 determines whether the speed of the fed document 104 in the main scanning direction MS exceeds a predetermined speed and then becomes equal to or lower than another speed within a predetermined time. If the speed in the main scanning direction MS becomes sufficiently small within a predetermined period of time, the CPU 202 determines that the document has been roughly set. On the other hand, if the speed in the main scanning direction MS does not become sufficiently small within the predetermined time, the CPU 202 determines that the document has been stapled.

(Stop control operation)
FIG. 12 is a flowchart showing a stop control operation for stopping abnormal conveyance. The CPU 202 executes a stop control operation according to a program stored in the ROM 141 (storage unit). The CPU 202 reads and writes data necessary for the stop control operation from the RAM 142 (storage unit).

When the CPU 202 receives an instruction to start reading from the user through the operation unit 201 (S201), the CPU 202 detects whether or not there is a document in the document tray 105 based on the detection result of the document set detection sensor 106 (S202). If it is determined that there is no document in the document tray 105 (NO in S202), the CPU 202 executes the pressure plate scan job (S203). The pressure plate scan job is an operation of reading a document placed on a platen glass (not shown), and its explanation will be omitted here. If it is determined that the document is in the document tray 105 (YES in S202), the CPU 202 enables the tracking sensor 111 (S204). The CPU 202 starts driving the transport motor 203 provided in the ADF 103 to transport the original (S205).

Thereafter, CPU 202 monitors for a predetermined period of time whether or not the document has reached pre-separation sensor 108 . Specifically, it is determined whether the pre-separation sensor 108 is turned on (S206). If the pre-separation sensor 108 is not on (NO in S206), the CPU 202 determines whether the first predetermined time has elapsed (S207). If the first predetermined time has elapsed (YES in S207), the CPU 202 determines that the document has not been conveyed because the document has not reached the pre-separation sensor 108 even after the first predetermined time elapses, It is determined that the original has jammed (original paper feed jam) (S208). Then, the CPU 202 stops the transport motor 203. If the first predetermined time has not elapsed (NO in S207), the CPU 202 returns the process to S206. When the document reaches the pre-separation sensor 108 within the first predetermined time (S206: YES), the CPU 202 starts sampling the tracking sensor 111 (S209).

After starting sampling (starting detection), the tracking sensor 111 samples an output value representing the amount of movement in the feeding direction CD and an output value representing the amount of movement in the main scanning direction MS at predetermined time intervals. The CPU 202 determines whether the output value in the feeding direction CD is greater than or equal to the first threshold (third speed) (S210). Here, the first threshold value is, for example, a speed that is 0.8 times the rotational speed (peripheral speed) of the pickup roller 107. If the output value of the tracking sensor 111 in the feeding direction CD is not equal to or greater than the first threshold (NO in S210), the CPU 202 determines whether a second predetermined time has elapsed (S211). If the second predetermined time has elapsed (YES in S211), the CPU 202 determines that the document has not been conveyed the predetermined distance even after the second predetermined time has elapsed, and determines that the document has jammed (original feed jam) (S212). Then, the CPU 202 stops the transport motor 203. If the second predetermined time has not elapsed (NO in S211), the CPU 202 returns the process to S210. If the output value of the feeding direction CD of the tracking sensor 111 becomes equal to or greater than the first threshold within the second predetermined time period (YES in S210), it is determined that the document has been transported for a predetermined distance or more after the detection starts. , the CPU 202 advances the process to S213.

The CPU 202 determines whether the output value of the tracking sensor 111 in the main scanning direction MS is equal to or greater than the second threshold (first speed) (S213). If the output value in the main scanning direction MS is not equal to or greater than the second threshold (NO in S213), the CPU 202 determines whether a third predetermined time has elapsed (S214). If the third predetermined time has elapsed (YES in S214), the CPU 202 advances the process to S215. If the third predetermined time has not elapsed (NO in S214), the CPU 202 returns the process to S213.

In S213, if the output value in the main scanning direction MS is equal to or greater than the second threshold (YES in S213), the CPU 202 causes the output value in the main scanning direction MS of the tracking sensor 111 to reach the third threshold within a fourth predetermined time. It is determined whether the speed has become lower than (second speed) (S216). Here, the third threshold value is set to a value smaller than the second threshold value described above. As described above, when the stapled document bundle 200 is fed, the movement amount 902 in the main scanning direction MS gradually decreases. Therefore, if the output value in the main scanning direction MS does not become equal to or less than the third threshold within the fourth predetermined time (NO in S216), the CPU 202 determines that the stapled document bundle 200 has been conveyed (S217). , the transport motor 203 is stopped (S218). Note that in S216, the CPU 202 determines the time period from when the output value in the main scanning direction MS becomes equal to or greater than the second threshold value in S213 until the elapse of a fourth predetermined time period. Further, in S217, the CPU 202 displays a notification on the operation unit 201 indicating that a stapled document has been detected.

On the other hand, when a roughly set document 104 is fed, the skew is suppressed when the document 104 reaches the document separation unit 150, so the movement amount 1102 in the main scanning direction MS tends to decrease significantly. be. Therefore, if the output value in the main scanning direction MS becomes equal to or less than the third threshold value within the fourth predetermined time (YES in S216), the CPU 202 determines that the unstapled (roughly set) document 104 has been conveyed. After making a determination, the process advances to S215.

In S215, the CPU 202 waits for the fifth predetermined time to elapse until the document 104 passes through the pre-separation sensor 108. Specifically, the CPU 202 determines whether the pre-separation sensor 108 is turned off (S215). If the pre-separation sensor 108 is not off (NO in S215), the CPU 202 determines whether a fifth predetermined time has elapsed (S219). If the fifth predetermined time has not elapsed (NO in S219), the CPU 202 returns the process to S215. If the fifth predetermined time has elapsed (YES in S219), the document 104 remains on the pre-separation sensor 108 even after the fifth predetermined time has elapsed, so it is determined that the document 104 has remained in the conveyance path, and the document It is determined that there is a jam (original paper feed jam) (S220). Then, the CPU 202 stops driving the transport motor 203.

If the pre-separation sensor 108 is turned off within the fifth predetermined time (YES in S215), the CPU 202 determines whether there is a next document in the document tray 105 (S221). If there is a document in the document tray 105 (YES in S221), the CPU 202 returns the process to S206. The CPU 202 continues to detect whether the next document is the stapled document bundle 200 or not. If it is determined that there are no originals on the original tray 105 (NO in S221), the CPU 202 determines that all the originals stacked on the original tray 105 have been transported, and stops driving the transport motor 203 (S218). The CPU 202 ends the stop control operation.

As described above, if the speed of the original in the main scanning direction does not become equal to or lower than the third threshold (equal to or lower than the second speed) between the time when the speed of the original in the width direction becomes equal to or higher than the second threshold (equal to or higher than the first speed) and the time when the fourth specified time has elapsed after the speed of the original in the width direction becomes equal to or higher than the second threshold (equal to or higher than the first speed), the CPU 202 continues feeding of the original. With the above control, it is possible to reduce erroneous detection by the CPU 202 that the stapled original stack 200 has been transported when the original 104 is roughly set.

Note that although the pickup roller 107 in this embodiment is arranged at the center of the document tray 105 in the width direction, the pickup roller 107 may be arranged at a position offset from the center of the document tray 105. In such a case, even if the original 104 is set in the center of the original tray 105, there is a risk that the original 104 will be skewed during feeding. However, with the control shown in FIG. 12, even if the pickup roller 107 is disposed at a position offset from the center of the document tray 105, it is possible to suppress the tracking sensor 111 from erroneously detecting an abnormal document.

100 Original reading device 105 Original tray 107 Pick-up roller 111 Tracking sensor 150 Original separating unit 202 CPU

Claims (7)

a loading means on which sheets are loaded;
Separating and feeding means for separating and feeding the sheets loaded on the loading means one by one;
speed detection means for detecting the speed of the sheet fed by the separation feeding means;
control means for controlling the separation and feeding means;
Equipped with
The control means includes:
The speed of the sheet in the width direction perpendicular to the feeding direction of the sheet detected by the speed detection means becomes equal to or higher than the first speed until a predetermined time elapses, If the speed does not become lower than a second speed smaller than the first speed, stopping the feeding of the sheet by the separation feeding means;
The speed of the sheet in the width direction increases to the second speed after the speed of the sheet in the width direction detected by the speed detection means becomes equal to or higher than the first speed until the predetermined time elapses. If the following occurs, continue feeding the sheet by the separation feeding means,
A sheet conveying device characterized by: The control means compares the speed of the sheet in the width direction with the first speed when the speed of the sheet in the feeding direction detected by the speed detection means becomes a third speed or higher. start,
The sheet conveying device according to claim 1, characterized in that: A sheet detection means is provided for detecting a sheet,
The control means starts detecting the sheet speed by the speed detection means based on the detection result of the sheet detection means.
2. The sheet transport device according to claim 1, wherein the sheet transport device is a sheet conveying device. The separating and feeding means includes a pickup roller that feeds the sheets loaded on the stacking means, and a sheet separating section that separates the sheets fed by the pickup roller at a position downstream of the pickup roller. ,
The sheet detection means detects the sheet between the pickup roller and the sheet separation section and at a position upstream of the detection position of the speed detection means.
The sheet conveying device according to claim 3, characterized in that: Equipped with a notification means to notify the user of information,
The control means is configured to control the speed of the sheet in the width direction after the speed of the sheet in the width direction detected by the speed detection means becomes equal to or higher than the first speed until the predetermined time elapses. If the speed does not become lower than the second speed, stopping the feeding of the sheet by the separating and feeding means, and notifying information indicating that the stapled sheet has been fed by the notification means;
The sheet conveying device according to claim 1, characterized in that: A sheet conveying device according to any one of claims 1 to 5,
a reading unit for reading an image of a sheet conveyed by the sheet conveying device;
An image reading device characterized by: An image reading device according to claim 6;
an image forming unit that forms an image on a recording medium based on the image of the sheet read by the reading unit;
An image forming apparatus characterized by:

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