JP2023153165A - Manuscript feeding device and image reading device - Google Patents

Abstract

To provide a manuscript feeding device and an image reading device, capable of reducing erroneous detection by a skew detection section.SOLUTION: The manuscript feeding device includes: a loading section loaded with a manuscript; a feeding section for feeding the manuscript loaded on the loading section in the feeding direction; a first sensor and a second sensor for detecting the manuscript fed by the feeding section at a detection position; a drive section for driving the feeding section; and a control section for controlling the drive section. The control section continues feeding of a subsequent manuscript following a preceding manuscript without stopping driving of the drive section regardless of the detection results of the first sensor and the second sensor before a rear end of the preceding manuscript passes through the detection position, and stops driving of the drive section and interrupts feeding of the subsequent manuscript when a time difference between a signal output by the first sensor and a signal output by the second sensor exceeds a threshold value during feeding of the subsequent manuscript after the rear end of the preceding manuscript passes through the detection position.SELECTED DRAWING: Figure 7

Description

The present invention relates to a document feeding device that feeds a document and an image reading device equipped with the same.

Generally, an image reading device is known that is placed on the top of the printer body and reads the image of the document. Auto Document Feeder). The ADF cannot separate and feed so-called "bound originals" such as stapled originals or glued originals, and the mechanism within the ADF that separates the originals may wrinkle or tear the originals. There are things to do. Furthermore, if bound documents are fed as they are without being separated in the ADF, there is a risk of jamming on the conveyance path.

Conventionally, a sheet feeding device has been proposed that has a plurality of skew detection sensors arranged in a straight line in the width direction perpendicular to the paper feeding direction (see Patent Document 1). For example, if this sheet feeding device feeds a bound document with the corners bound, the uppermost document of the bound document will be fed while being rotated. Then, the sheet feeding device detects, using a plurality of skew detection sensors, that the bound document being fed is being conveyed while being rotated, and stops feeding the document.

Japanese Patent Application Publication No. 2006-193287

However, in the sheet feeding device described in Patent Document 1, for example, when feeding a document with punched holes, when the punched hole passes over the skew detection sensor, the skew detection sensor changes from ON to OFF. Turn it on again from OFF. Then, there is a possibility that the sheet feeding device may erroneously recognize the detection result of the skew detection sensor as the detection of the leading edge of the document to be fed next. At this time, there is a possibility that it will be erroneously detected that the document is skewed, and the feeding of the document will be stopped unintentionally.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a document feeding device and an image reading device that can reduce false detections by a skew detection section.

The present invention provides a document feeding device that includes a stacking section on which documents are stacked, a feeding section that feeds the documents stacked on the stacking section in a feeding direction, and a document fed by the feeding section. a separating section that separates the documents one by one, and a feeding section that is downstream of the separating section in the feeding direction and arranged at different positions in the width direction of the document perpendicular to the feeding direction. The control unit includes a first sensor and a second sensor that detect a fed document at a detection position, a drive unit that drives the feeding unit, and a control unit that controls the drive unit. After the leading edge of the preceding document fed by the feeding section passes the detection position, but before the trailing edge of the preceding document passes the detection position, the detection results of the first sensor and the second sensor are detected. Regardless, the driving of the drive unit is not stopped, and the subsequent document that follows the preceding document continues to be fed, and after the trailing edge of the preceding document passes the detection position, the subsequent document is fed. During feeding, if the time difference between the signal output by the first sensor and the signal output by the second sensor exceeds a threshold, the drive of the drive unit is stopped to interrupt feeding of the subsequent document. , is characterized by.

According to the present invention, false detection by the skew detection section can be reduced.

(a) is an overall schematic diagram showing a printer, and (b) is a schematic diagram showing an image forming engine. FIG. 3 is a plan view showing the arrangement of skew detection sensors. FIG. 2 is a block diagram showing a control system. Flowchart showing copy operation. Flowchart showing a document length calculation process. (a) is a plan view showing the document located at the feeding start position, (b) is a plan view showing the document located at the time measurement start position, and (c) is a plan view showing the document located at the time measurement end position. Flowchart showing the skew detection process. (a) is a plan view showing the position of the document when the presence or absence of skew is determined; (b) is a plan view showing the position of the document when the punch hole reaches the skew detection sensor; (c) is a plan view showing the position of the document when the punched hole reaches the skew detection sensor. FIG. 7 is a plan view showing the position of the document at the time when the trailing edge passes the sensor after separation. (a) is a plan view showing a bound original, and (b) is a plan view showing a state in which the bound original is fed.

[overall structure]
Printer 100 as an image forming apparatus according to this embodiment is an electrophotographic laser beam printer. The printer 100 includes a printer main body 70 and an image reading device 10 mounted on the top of the printer main body 70, as shown in FIG. 1(a). Note that in the following, sheets include not only plain paper but also special papers such as coated paper, recording materials with special shapes such as envelopes and index papers, and plastic films and cloth for overhead projectors. A manuscript is also an example of a sheet.

The printer main body 70 has an image forming engine 60 therein. The image forming engine 60 includes an image forming unit PU as an electrophotographic image forming section and a fixing device 7, as shown in FIG. 1(b). When a command is given to start an image forming operation, a photosensitive drum 1, which is a photosensitive member, rotates, and the surface of the drum is uniformly charged by a charging device 2. Then, the exposure device 3 modulates and outputs a laser beam based on image data transmitted from the image reading device 10 or an external computer, and scans the surface of the photosensitive drum 1 to form an electrostatic latent image. This electrostatic latent image is visualized (developed) by toner supplied from the developing device 4 and becomes a toner image.

In parallel with such an image forming operation, a feeding operation is performed in which sheets stacked in a cassette or a manual feed tray (not shown) are fed toward the image forming engine 60. The fed sheet is conveyed in accordance with the progress of the image forming operation by the image forming unit PU. The toner image carried on the photosensitive drum 1 is then transferred onto a sheet by a transfer roller 5. Toner remaining on the photosensitive drum 1 after the toner image transfer is collected by a cleaning device 6. The sheet onto which the unfixed toner image has been transferred is delivered to the fixing device 7, where it is held between a pair of rollers and heated and pressurized. The sheet on which the image is fixed by melting and fixing the toner to the sheet is discharged by a discharge portion such as a discharge roller.

[Image reading device]
Next, the image reading device 10 will be described in detail. As shown in FIG. 1(a), the image reading device 10 includes an ADF 20 serving as a document feeding device that feeds a document D loaded on a document tray 21 and discharges the document D to an ejection tray 32, and a document feeder that feeds the document D loaded on a document tray 21 and discharges the document D onto a discharge tray 32. It is equipped with a reading unit 40 for reading. The ADF 20 (Auto Document Feeder) is rotatably supported by a hinge with respect to the reading unit 40 so that the document table glass 41 can be opened. Note that the document D may be a blank paper, or may have an image formed on one or both sides.

The ADF 20 includes a pickup roller 22 as a feeding section, a separation drive roller 23 and a separation driven roller 24, a registration roller pair 25, a transport roller pair 26, 30, a platen guide roller 27, and a discharge roller pair 31. ,have. The ADF 20 also includes a document presence/absence sensor S31 that detects the document D on the document tray 21, a post-separation sensor S32 that is disposed downstream of the separation drive roller 23 in the feeding direction and detects the document D, and a post-separation sensor S32 that detects the document D when the document D is skewed. It has skew detection sensors S1 and S2 that detect skew detection sensors S1 and S2.

The reading unit 40 as an image reading section includes a platen glass 28, a jump table 29, a reference white plate 42, a document table glass 41, a first mirror table 43, a second mirror table 44, a lens 45, and a CCD. It has a line sensor 46. A lamp 47 and a mirror 48 are arranged inside the first mirror stand 43, and mirrors 49 and 50 are arranged inside the second mirror stand 44. The first mirror stand 43 and the second mirror stand 44 are configured to be movable in the sub-scanning direction, which is the left-right direction in the figure, by a wire and a drive motor (not shown).

The image reading device 10 operates in a continuous reading mode in which the original D loaded on the original tray 21 is fed by the ADF 20 while scanning the original image, and in a fixed reading mode in which the original placed on the original platen glass 41 is scanned. Image information is read from the document D. The skimming mode is selected when the document presence/absence sensor S31 detects the document D stacked on the document tray 21 serving as a stacking section, or when the user explicitly instructs it through the operation panel of the printer main body 70 or the like.

When the skimming mode is executed, the pickup roller 22 supported by an arm (not shown) descends and comes into contact with the uppermost document D on the document tray 21 . The document D is set on the document tray 21 with the position of the end portion in the width direction being restricted by the side regulating plates 21a and 21b (see FIG. 2).

Then, the document D is fed by a pickup roller 22 and separated into sheets one by one at a separation nip N serving as a separation section formed by a separation drive roller 23 and a separation driven roller 24. The separation drive roller 23 is made of a rubber material or the like that has slightly less friction than the separation driven roller 24. A torque limiter is disposed on the drive transmission path to the separation driven roller 24, and when the number of fed documents is one, the separation driven roller 24 follows the separation drive roller 23 to prevent the fed document from being fed. It does not rotate when there are two or more pieces. Therefore, the documents can be separated one by one. Note that driving in the direction opposite to the feeding direction may be input to the separation driven roller 24.

The leading edge and trailing edge of the document that has passed through the separation nip N are detected by the post-separation sensor S32, and the timing of the rise and fall of the pickup roller 22, the drive start and drive stop timings, and the drive start and drive stop timing of the registration roller pair 25 are determined. Become a standard.

The leading edge of the transported document D hits the registration roller pair 25 in a stopped state, and the skew of the document D is corrected. The original D whose skew has been corrected is transported by a pair of registration rollers 25 and then transported toward a platen glass 28 by a pair of transport rollers 26 . The platen guide roller 27 is arranged to face the platen glass 28 and guides the document D passing through the platen glass 28 so that it does not float off the platen glass 28.

Then, the image on the front surface of the document D is read by the reading unit 40 via the platen glass 28. Specifically, the light from the lamp 47 is irradiated onto the document D being conveyed, and the reflected light from the document D is guided to the lens 45 via mirrors 48, 49, and 50. The light passing through the lens 45 forms an image on the light receiving section of the CCD line sensor 46, undergoes photoelectric conversion, and transmits image information to the CPU 81. Note that the reference white board 42 serves as a reference for the reading brightness of the document D. The document D that has passed through the platen glass 28 is guided to a pair of transport rollers 30 by a jump table 29, and is discharged onto a discharge tray 32 by a pair of discharge rollers 31.

On the other hand, the fixed reading mode is selected when the apparatus detects the original D placed on the original table glass 41 or when the user explicitly instructs it through the operation panel of the printer main body 70 or the like. In this case, the document D on the document table glass 41 does not move, and the first mirror table 43 and the second mirror table 44 move along the document table glass 41. Then, the original D is scanned by the light emitted from the lamp 47. Image information photoelectrically converted by the light receiving element of the CCD line sensor 46 is transferred to the CPU 81.

[Oblique detection sensor]
As shown in FIG. 2, the skew detection sensors S1 and S2 include a skew detection section 90 that detects the skew of the document D at a detection position DP located downstream of the pickup roller 22 and the separation nip N in the feeding direction FD. It consists of The skew detection sensors S1 and S2 have the same configuration, and are, for example, photo interrupters having a light emitting section that irradiates light onto the document D, and a light receiving section that receives light emitted from the light emitting section and reflected on the document D. It consists of The skew detection sensors S1 and S2 as a plurality of sensors are arranged at different positions in the width direction W perpendicular to the feeding direction FD, and output signals based on the presence or absence of a document at each position in the width direction W. Output.

More specifically, the skew detection sensor S1 as the first sensor is arranged on one side in the width direction W with respect to a center line CL that is the center in the width direction W of the conveyance path CP through which the document passes. . The skew detection sensor S2 as the second sensor is arranged on the other side in the width direction W with respect to the center line CL. Note that in this embodiment, two skew detection sensors S1 and S2 are provided, but any number of skew detection sensors S1 and S2 may be provided as long as it is two or more. The post-separation sensor S32 is disposed downstream of the pickup roller 22 and upstream of the detection position DP in the feeding direction FD.

[Control block]
FIG. 3 is a control block diagram of the CPU 81 as a control section. As shown in FIG. 3, the input side of the CPU 81 is connected to skew detection sensors S1 and S2, a document presence/absence sensor S31, and a post-separation sensor S32. A pickup motor 84 and a separation drive motor 85 are connected to the output side of the CPU 81 via a motor control section 83 . A pickup motor 84 serving as a drive unit drives the pickup roller 22 , and a separation drive motor 85 drives the separation drive roller 23 .

Further, an operation unit 506, a storage unit 507, and a document length calculation unit 508 are connected to the CPU 81. The operation unit 506 includes, for example, an operation panel, and can start a copy job and perform various settings. The storage unit 507 stores a threshold value Tth [ms] for detecting the skew of the document D by the skew detection sensors S1 and S2. The document length calculation unit 508 calculates the length of the document D in the sub-scanning direction (feeding direction FD) from the detection result of the post-separation sensor S32 as a length detection unit, and sends the calculated length of the document D to the CPU 81. Enter.

[Copy operation]
Next, the copying operation by the image reading device 10 will be explained along the flowchart shown in FIG. In this embodiment, a "bound document" refers to a document bundle in which a plurality of documents are connected in the thickness direction of the document by stapling, gluing, or the like, or a single document in the document bundle. Further, the "bound original" is not limited to a staple-stitched or glued original, but may also be a stapleless-stitched or book-bound original.

First, as shown in FIG. 4, the CPU 81 determines whether a document is stacked on the document tray 21 using the document presence/absence sensor S31 (step S101). If no originals are stacked on the original tray 21 (step S101: NO), the CPU 81 does not proceed to the next process and waits until the originals are stacked on the original tray 21.

If it is determined that a document is stacked on the document tray 21 (step S101: YES), the CPU 81 determines whether or not the start of a copy job has been instructed (step S102). If the start of the copy job is not instructed from the operation unit 506 (step S102: NO), the CPU 81 does not proceed to the next process and waits until the start of the copy job is instructed.

If it is determined that the start of the copy job has been instructed (step S102: YES), the CPU 81 causes the pickup roller 22 to feed the document D (step S103). When the original D is fed, the CPU 81 determines whether the fed original is the first sheet of the job (step S104). If the fed document is the first sheet of the job (step S104: YES), the CPU 81 performs a document length calculation process (step S105) and a skew detection process (step S106), which will be described later, in parallel. If the fed document is the second or subsequent sheet of the job (step S104: NO), the CPU 81 performs only the skew detection process (step S106) without performing the document length calculation process (step S105).

Next, the CPU 81 determines whether skew feeding of the document D is detected in the skew detection process (step S106) (step S107). In this embodiment, if it is determined in step S107 that skew feeding has been detected, it is determined that, for example, a bound document has been fed. When the bound original is fed, the bound original rotates around the binding portion of the bound original. As a result, the leading edge of the fed bound document is skewed. Therefore, when the skew of the document D is detected (step S107: YES), the CPU 81 stops the feeding of the document D by stopping the pickup motor 84 and the separation drive motor 85 (step S108), and starts the process. finish.

If the skew of the document D is not detected (step S107: NO), the CPU 81 determines whether the fed document D is the last document loaded in the copy job or the document tray 21 (step S109). ). If it is determined that it is the final manuscript (step S109: YES), the process advances to step S108. If it is determined that it is not the final document (step S109: NO), the process returns to step S103 and the next document is fed.

Note that steps S106, S107, and S108 in this embodiment constitute a stop process for stopping the document feeding by the pickup roller 22 based on the detection result by the skew detection section 90.

[Manuscript length calculation process]
Next, the document length calculation process (step S105 in FIG. 4) will be explained along the flowchart shown in FIG. As shown in FIG. 5, when the document length calculation process is started, the CPU 81 determines whether the post-separation sensor S32 is turned on (step S201). Note that the post-separation sensor S32 is composed of a photointerrupter, for example, similar to the skew detection sensors S1 and S2, and is turned on when the document D exists at the detection position of the post-separation sensor S32, and turns on when the document D does not exist. It becomes OFF.

Note that in the following, the first document of the job is referred to as document D1, the second document of the job is referred to as document D2, the third document of the job is referred to as document D3, and the fourth document of the job is referred to as document D4. explain.

When the post-separation sensor S32 is OFF (step S201: NO), the CPU 81 does not proceed to the next process and waits until the post-separation sensor S32 is turned on. When the post-separation sensor S32 is turned on (step S201: YES), the CPU 81 starts measuring time using a timer (not shown) (step S202). At this time, the document D1 has progressed from the feeding start position shown in FIG. 6(a) to the timing start position shown in FIG. 6(b), and the leading edge has just reached the detection position of the post-separation sensor S32. Note that the timer may be built into the CPU 81 or may be provided outside the CPU 81.

Next, the CPU 81 determines whether the post-separation sensor S32 is turned off (step S203). If the post-separation sensor S32 remains ON (step S203: NO), the CPU 81 does not proceed to the next process and waits until the post-separation sensor S32 is turned off. When the post-separation sensor S32 is turned off (step S203: YES), the CPU 81 ends the time measurement by the timer (step S204). At this time, the document D1 has advanced to the timing end position shown in FIG. 6(c), and the trailing edge has just passed the detection position of the post-separation sensor S32.

Then, the CPU 81 calculates the document length Lv [mm] based on the time measured by the timer from step S202 to step S204 and the conveyance speed of the document D (step S205). For example, if the time measured by the timer is 142 [ms] and the transport speed of the document D1 is 260 [mm/s], the document length Lv is calculated to be 260 x 1.142 = 296.92 [mm]. Ru. The calculated document length Lv is stored in the storage unit 507 (see FIG. 3).

[Oblique detection process]
Next, the skew detection process (step S106 in FIG. 4) will be explained along the flowchart shown in FIG. In the following description, it is assumed that the document length calculation process for the first document D1 of the job has already been completed, and the document length Lv [mm] has already been stored in the storage unit 507. The skew detection process when the originals D2 and D3 are fed will be described below. The document D3 is, for example, the highest document among the bound documents.

As shown in FIG. 7, when the skew detection process is started, the CPU 81 determines whether the skew detection sensor S1 is turned on (step S301). If it is determined that the skew detection sensor S1 is turned on (step S301: YES), the CPU 81 determines whether the skew detection sensor S2 is turned on (step S302). If it is determined that the skew detection sensor S2 is turned on (step S302: YES), the CPU 81 determines that the skew of the document D2 is not detected (step S303).

Here, the behavior of the uppermost document of the bound documents when the bound documents are fed will be explained using FIGS. 9(a) and 9(b). As shown in FIG. 9A, the originals D3 and D4 form part of a bound original bound with staples ST, and the original D3 is the uppermost original of the bound originals. Document D4 is a document adjacent to document D3.

When the pickup roller 22 comes into contact with the upper surface of the document D3 and the pickup roller 22 starts feeding the document D3, the document D3 is fed while rotating around the staple ST, as shown in FIG. 9(b). be done. This is because the document D3 and the document D4 are separated by the separation drive roller 23 and the separation driven roller 24, and only the document D3 is transported by the pickup roller 22 and the separation drive roller 23.

When the document D3 is fed in this manner, the staple ST side of the document D3 is not conveyed in the width direction W, and only the side of the document D3 opposite to the staple ST advances downstream in the feeding direction. Therefore, although the skew detection sensor S1 remains OFF, only the skew detection sensor S2 is turned ON, and it is detected that the document D3 is skewed.

Returning to the explanation of the flowchart in FIG. 7, if it is determined in step S301 that the skew detection sensor S1 is not turned on (step S301: NO), the CPU 81 determines whether the skew detection sensor S2 is turned on. is determined (step S304). If it is determined that the skew detection sensor S2 is not turned on (step S304: NO), the process returns to step S301.

If it is determined that the skew detection sensor S2 is turned on (step S304: YES), the CPU 81 determines again whether the skew detection sensor S1 is turned on (step S305). If it is determined that the skew detection sensor S1 is turned on (step S305: YES), the process advances to step S303.

If it is determined that the skew detection sensor S1 is not turned on (step S305: NO), the CPU 81 determines whether the threshold value Tth [ms] has elapsed after the skew detection sensor S2 was turned on. A judgment is made (step S306). If it is determined that the threshold Tth [ms] has not elapsed (step S306: NO), the process returns to step S305. If it is determined that the threshold value Tth [ms] has elapsed (step S306: YES), the CPU 81 determines that skew feeding of the document D2 has been detected (step S308).

Similarly, if it is determined in step S302 that the skew detection sensor S2 is not turned on (step S302: NO), the CPU 81 sets the threshold value Tth [ms] after the skew detection sensor S1 is turned on. It is determined whether or not the period has elapsed (step S307). If it is determined that the threshold value Tth [ms] has elapsed (step S307: YES), the CPU 81 determines that skew feeding of the document D2 has been detected (step S308).

The threshold value Tth [ms] is a value stored in the storage unit 507, and is determined by the conveyance speed of the document. In this embodiment, the threshold value Tth [ms] is set to 30 [ms], for example. Note that the threshold values in step S306 and step S307 do not have to be set to the same value, and different threshold values may be set for each. In any case, in steps S306 and S307, it is determined whether the time difference between the signal output by the skew detection sensor S1 and the signal output by the skew detection sensor S1 exceeds a predetermined threshold. Then, when this time difference exceeds a predetermined threshold value, skew feeding of the document is detected.

After the processing in step S303 or step S308, the CPU 81 determines whether the currently fed document is the first sheet of the job (step S309). If the currently fed document is the first sheet of the job (step S309: YES), the process ends. If the document currently being fed is not the first sheet of the job (step S309: NO), the CPU 81 waits until the trailing edge of the document currently being fed passes the skew detection sensors S1 and S2. The outputs of the row detection sensors S1 and S2 are ignored (step S310). As a result, even if the outputs of the skew detection sensors S1 and S2 are values that indicate that the document is being skewed, it is determined that the document is not being skewed.

Here, step S310 will be explained in more detail using FIGS. 8(a) to 8(c). In the following, a case where the document D2 is a document with holes will be described as an example. A plurality of punch holes Pd are formed along the width direction W at the rear end of the document D2. FIG. 8A shows the position of the document D2 at the time when the CPU 81 determines whether or not the document D2 is skewed. FIG. 8B shows the position of the document D2 at the time when the punch hole Pd of the document D2 passes the skew detection sensors S1 and S2. FIG. 8C shows the position of the document D2 at the time when the trailing edge 91 of the document D2 passes the skew detection sensors S1 and S2.

As shown in FIG. 8(b), when the punch hole Pd of the document D2 passes the skew detection sensors S1 and S2, if the signals of the skew detection sensors S1 and S2 are used to determine whether the document is skewed, If the document is being fed diagonally, it may be falsely detected and feeding of the document may be stopped unintentionally. For example, if only the skew detection sensor S1 is turned OFF/ON by the punch hole Pd, and the skew detection sensor S2 remains ON, the time difference between the signal output by the skew detection sensor S1 and the signal output by the skew detection sensor S1 is may exceed the threshold.

Therefore, in step S310, the CPU 81 ignores the signals that are the outputs of the skew detection sensors S1 and S2 from the time point in FIG. 8(a) to the time point in FIG. 8(c). Specifically, the CPU 81 detects the skew detection sensor S1, S2 from the end of the skew detection of the document D2 being fed until the trailing edge 91 of the document D2 passes the skew detection sensors S1, S2. Ignore the S2 signal.

At this time, the conveyance amount of the document D2 required for the trailing edge 91 of the document D2 to pass the skew detection sensors S1 and S2 is determined by the value calculated in the document length calculation process (step S105) and the skew detection sensor. It is predicted from the positions of S1 and S2. Here, the distance in the feeding direction FD between the post-separation sensor S32 and the skew detection sensors S1 and S2 is defined as a distance ds [mm]. Then, if the document D2 is conveyed by a distance ds+Lv [mm] from the time when the leading edge 92 of the document D2 reaches the post-separation sensor S32, it can be expected that the rear end 91 of the document D2 will pass the skew detection sensors S1 and S2. In this embodiment, for example, the distance ds [mm] is set to 20 [mm].

Therefore, the distance ds + Lv = 20 + 296.92 = 316.92 [mm], and if the original D2 is conveyed more than 316.92 [mm] from the time when the leading edge of the original D2 reaches the sensor S32 after separation, the following The ends pass through the skew detection sensors S1 and S2. This reduces the possibility of erroneously detecting skew feeding of the document D3 as a subsequent document due to the punch hole Pd of the document D2 as a preceding document, and prevents the feeding of the document from unintentionally stopping. .

In particular, in recent image forming apparatuses, productivity has been improved by shortening the distance between the preceding original and the following original (the so-called paper distance), and the skew detection sensor S1, S2 Feeding of a subsequent document may start while the document is passing through the document. In this case, it is determined that the subsequent document is skewed due to the erroneous detection by the skew detection sensors S1 and S2 due to the punched hole in the preceding document, and the feeding of the subsequent document may be stopped unintentionally. There is.

In this embodiment, since the signals from the skew detection sensors S1 and S2 are ignored until the trailing edge of the preceding document passes through the skew detection sensors S1 and S2, false detections by the skew detection sensors S1 and S2 are reduced. , it is possible to prevent unintentional document stoppage. That is, after the leading edge of the preceding document passes the detection position DP of the skew detection sensors S1 and S2, but before the trailing edge of the preceding document passes the detection position DP, the detection of the skew detection sensors S1 and S2 is Regardless of the result, stop processing is not executed for subsequent documents. In other words, feeding of the subsequent original is continued. After the trailing edge of the preceding document passes the detection position DP, the time difference between the signal output by the skew detection sensor S1 and the signal output by the skew detection sensor S2 exceeds the threshold Tth while the subsequent document is being fed. If so, the drive of the pickup motor 84 is stopped. As a result, the stop process is executed for the subsequent document, and the feeding of the subsequent document is interrupted.

Note that in this embodiment, an example has been described in which the signals from the skew detection sensors S1 and S2 are ignored until the trailing edge of the second document D2 of the job passes through the skew detection sensors S1 and S2. It is not limited to this. For example, while executing the document length calculation process for the first document D1 of the job, the signals from the skew detection sensors S1 and S2 are may be ignored. Furthermore, it is of course possible to ignore the signals from the skew detection sensors S1 and S2 until the trailing edge of the third and subsequent documents of the job passes.

Furthermore, although the present embodiment has been described using the document D2 having the punch holes Pd, the present invention is applicable not only to the punch holes Pd but also to documents with bent corners, partially damaged documents, and the like.

Further, in the present embodiment, control is performed to ignore the signals of the skew detection sensors S1 and S2 in step S310, but the present invention is not limited to this. For example, the signals of the skew detection sensors S1 and S2 may be controlled not to be outputted, or the power supply to the skew detection sensors S1 and S2 may be stopped.

Further, in the present embodiment, the length of the document is detected by executing the document length calculation process with the sensor S32 after separation for the first document D1 of the job, but the present invention is not limited to this. Not done. For example, the document length information may be input from the operation unit 506 provided in the printer 100, an external computer, or the like. Further, until the side regulating plates 21a and 21b are operated, the document length information in the previous job may be continued to be used, and the document length calculation process may be omitted.

Furthermore, in the present embodiment, the timing at which the trailing edge of the document passes the skew detection sensors S1 and S2 is predicted using the detection result of the post-separation sensor S32, but the present invention is not limited to this. For example, it is determined from the leading edge position of the original set on the original tray 21, the positions of the skew detection sensors S1 and S2, and the original length Lv that the trailing edge of the original passes through the skew detection sensors S1 and S2. Good too.

Further, in this embodiment, the post-separation sensor S32 and the skew detection sensors S1 and S2 are composed of photointerrupters, but other sensors such as a flag type or a pressure sensitive type may be applied. Further, although the CPU 81 provided in the printer body 70 executes the control such as the document length calculation process and the skew detection process, the control is not limited to this. For example, the CPU provided in the image reading device 10 executes the control may be executed.

Note that in any of the embodiments described above, an electrophotographic printer is used, but the present invention is not limited thereto. For example, the present invention can be applied to an inkjet image forming apparatus that forms an image on a sheet by ejecting ink liquid from a nozzle.

10: Image reading device / 20: Document feeding device (ADF) / 21: Stacking section (document tray) / 22: Feeding section (pickup roller) / 40: Image reading section (reading unit) / 81: Control section ( CPU) / 84: Drive unit (pickup motor) / 91: Trailing edge / CL: Center (center line) / CP: Conveyance path / D2: Leading original (original) / D3: Following original (original) / DP: Detection position /FD: Feeding direction /N: Separation nip /Pd: Hole (punch hole) /S1: First sensor (skew detection sensor) /S2: Second sensor (skew detection sensor) /S32: Length detection section (Sensor after separation)/Tth: Threshold/W: Width direction

The present invention provides a document feeding device that includes a stacking section on which documents are stacked, a feeding section that feeds the documents stacked on the stacking section in a feeding direction, and a document fed by the feeding section. a first sensor arranged downstream of the separating section in the feeding direction and detecting the document fed by the feeding section; a second sensor for detecting the document fed by the feeding section, the second sensor being disposed downstream of the feeding section and at a different position from the first sensor in the width direction of the document perpendicular to the feeding direction; and when the other of the first sensor and the second sensor does not detect the document within a predetermined period of time after one of the first sensor and the second sensor detects the document, the feeding section a control unit that executes a stop process for stopping the feeding of the original by the controller , and the control unit executes a stop process for stopping the feeding of the original by one of the first sensor and the second sensor until the predetermined time elapses after one of the first sensor and the second sensor detects the original. When the other of the first sensor and the second sensor detects the document, the trailing edge of the document is detected after the leading edge of the document passes through the detection positions of the first sensor and the second sensor. The stopping process based on the detection results of the first sensor and the second sensor is not executed before the vehicle passes the detection position.
Further, the present invention provides a document feeding device including a stacking section on which documents are stacked, a feeding section that feeds the documents stacked on the stacking section in a feeding direction, and a document feeding section that feeds the documents stacked on the stacking section in a feeding direction. a separating section that separates the original document into sheets one by one; a first sensor that is disposed downstream of the separating section in the feeding direction and detects the document fed by the feeding section; a second sensor configured to detect the document fed by the feeding section, the second sensor being disposed downstream of the separating section and at a different position from the first sensor in the width direction of the document orthogonal to the feeding direction; If the other of the first sensor and the second sensor does not detect the document within a predetermined period of time after one of the first sensor and the second sensor detects the document, the document is skewed. a control unit that determines that the first sensor and the second sensor When the other of the second sensors detects the document, after the leading edge of the document has passed the detection positions of the first sensor and the second sensor, the trailing edge of the document passes the detection position. The former is characterized in that skew detection is not performed based on the detection results of the first sensor and the second sensor.
Further, the present invention provides a document feeding device including a stacking section on which documents are stacked, a feeding section that feeds the documents stacked on the stacking section in a feeding direction, and a document feeding section that feeds the documents stacked on the stacking section in a feeding direction. a separating section that separates the original document into sheets one by one; a first sensor that is disposed downstream of the separating section in the feeding direction and detects the document fed by the feeding section; a second sensor configured to detect the document fed by the feeding section, the second sensor being disposed downstream of the separating section and at a different position from the first sensor in the width direction of the document orthogonal to the feeding direction; If the other of the first sensor and the second sensor does not detect the document within a predetermined period of time after one of the first sensor and the second sensor detects the document, the document is stapled. a control unit that determines whether the document is bound; When the other of the second sensors detects the document, after the leading edge of the document passes the detection positions of the first sensor and the second sensor, the trailing edge of the document passes the detection position. The former is characterized in that staple detection is not performed based on the detection results of the first sensor and the second sensor.

Claims (8)

a stacking section on which documents are stacked;
a feeding section that feeds the documents stacked on the stacking section in a feeding direction;
a separation unit that separates the original fed by the feeding unit into individual sheets;
A first detecting position, which is located downstream of the separation unit in the feeding direction and at different positions in the document width direction perpendicular to the feeding direction, detects the original fed by the feeding unit at a detection position. a first sensor and a second sensor;
a drive unit that drives the feeding unit;
A control unit that controls the drive unit,
The control unit controls the first sensor and the control unit after the leading edge of the preceding document fed by the feeding unit passes the detection position and before the trailing edge of the preceding document passes the detection position. Regardless of the detection result of the second sensor, the driving of the drive unit is not stopped, and the subsequent document that follows the preceding document continues to be fed, and the trailing edge of the preceding document passes the detection position. After that, if the time difference between the signal output by the first sensor and the signal output by the second sensor exceeds a threshold while feeding the subsequent document, the drive of the drive unit is stopped and the subsequent document is fed. interrupting the feeding of the original,
A document feeding device characterized by: The control unit ignores signals from the first sensor and the second sensor in detecting skew feeding of the subsequent document until the trailing edge of the preceding document passes the first sensor and the second sensor. do,
The document feeding device according to claim 1, characterized in that: The first sensor is disposed on one side in the width direction with respect to the center in the width direction of the conveyance path through which the document fed by the feeding unit passes,
the second sensor is arranged on the other side in the width direction with respect to the center;
The document feeding device according to claim 1 or 2, characterized in that: further comprising a length detection unit that detects the length of the document fed by the feeding unit in the feeding direction,
The control unit determines that the trailing edge of the preceding document has passed the detection position based on the detection result of the length detection unit.
The document feeding device according to any one of claims 1 to 3, characterized in that: The length detection section is arranged downstream of the feeding section and upstream of the detection position in the feeding direction.
The document feeding device according to claim 4, characterized in that: the preceding manuscript is a manuscript with holes;
The document feeding device according to any one of claims 1 to 5. The subsequent document is the highest document in a document bundle in which a plurality of documents are connected in the thickness direction of the document.
The document feeding device according to any one of claims 1 to 6, characterized in that: A document feeding device according to any one of claims 1 to 7,
an image reading unit that reads an image of a document fed by the document feeding device;
Equipped with
An image reading device characterized by:

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