JP7292787B2 - SHEET FEEDING DEVICE, CONTROL METHOD FOR SHEET FEEDING DEVICE, AND PROGRAM - Google Patents

Description

The present invention can be applied to a sheet feeder capable of feeding sheets, such as thin paper, slips, old papers (history books), already wrinkled documents, already folded documents, torn documents, etc. relating to feeding technology.

FIG. 25 is a diagram illustrating the configuration of a sheet feeding device that feeds a predetermined amount of paper.
In a conventional sheet feeding device, when feeding a plurality of sheets continuously, each time a sheet is fed, the pickup roller 4 is moved to the sheet take-in position, brought into contact with the sheet, and rotated. After that, the operation of moving to the retracted position was repeated. However, when the sheet is thin paper or the like with low stiffness, a jam may occur between the pair of separation rollers 6 and 7 and the pickup roller 4 .

Japanese Patent Laid-Open No. 2002-100003 proposes a countermeasure against jamming of sheets such as thin paper.
In Patent Document 1, after the pre-registration sensor 32 detects the trailing edge of the previously fed sheet, if the pre-registration sensor 32 does not detect the leading edge of the next sheet even after a specific time elapses, the pick-up A technique has been proposed in which the use of the pickup roller 4 is minimized and the sheet is fed by rotating the roller 4 in contact with the sheet.

JP-A-6-9110

The technique disclosed in Japanese Patent Application Laid-Open No. 2002-200000 has a certain effect in preventing jams caused by thin sheets or other sheets having weak stiffness. However, if the pickup roller 4 is rotated at the same time as the pickup roller 4 is brought into contact with the sheet, a jam may occur.

FIG. 26 is a graph illustrating changes in contact pressure on the sheet after the pick-up roller 4 is brought into contact with the sheet.
As shown in FIG. 26, the contact pressure of the pickup roller 4 to the sheet changes until the time TC elapses after the pickup roller 4 starts contacting the sheet. When the contact pressure is strong, the frictional force between the sheets also increases, so if the pickup roller 4 starts rotating before the time TC elapses, the sheets may be brought in and a jam may occur. rice field.

In addition, the pick-up roller 4 and the like wear out due to use, not limited to the case of conveying documents that are particularly vulnerable to load. As the wear of the roller progresses, it may become impossible to feed sheets normally, so it is desirable to avoid wasteful use as much as possible.

The present invention has been made to solve the above problems. SUMMARY OF THE INVENTION It is an object of the present invention to provide a mechanism that makes it difficult for paper jams to occur during paper feeding, even if the sheets to be fed are thin paper or the like with low stiffness.

According to the present invention, a fetching means for fetching a sheet by rotating while being in contact with the sheet stacked on the sheet stacking table, a feeding means for feeding the fetched sheet in the feeding direction, and a feeding means for feeding the sheet. a detecting means for detecting a sheet that is already fed in a predetermined first mode, and when a plurality of sheets are continuously fed in a predetermined first mode, after the detecting means detects the trailing edge of the previously fed sheet, the first If the leading edge of the next sheet is not detected even after the lapse of the specific time, the fetching means is brought into contact with the sheet stacked on the sheet stacking table, and after the lapse of the second specific time, the fetching means a control means for controlling the retrieving means to rotate in a retrieving direction, and to separate the retrieving means from the sheet after the detection means has detected the leading edge of the sheet; By bringing the loading means into contact with the sheets stacked on the sheet stacking table, the preset contact pressure on the sheets changes longer than a preset contact pressure change time, and the control means controls the When the detecting means detects the leading edge of the sheet before the second specific time elapses, the fetching means is separated from the sheet without rotating the fetching means in contact with the sheet. characterized by

According to the present invention, even if the sheet to be fed is thin paper or the like with low stiffness, it is possible to prevent jams from occurring during feeding.

FIG. 2 is a partial cross-sectional view of a sheet conveying device including the sheet feeding device according to the first embodiment; FIG. 2 is a schematic diagram schematically showing the configuration of the main parts of the sheet conveying device; 4 is a flowchart for explaining control operations in a thin paper mode according to the first embodiment; 4 is a timing chart showing an example of operations of a pre-registration sensor and a pickup roller according to the first embodiment; FIG. 10 is a partial cross-sectional view of a sheet conveying device provided with a sheet feeding device according to a second embodiment; 10 is a flowchart for explaining control operations in a thin paper mode according to the third embodiment; FIG. 11 is a timing chart showing an example of operations of a pre-registration sensor, a pickup roller, and a pair of registration rollers according to the fourth embodiment; FIG. FIG. 11 is a timing chart showing an example of operations of a pre-registration sensor, a pickup roller, and a feeding roller according to the fifth embodiment; FIG. FIG. 11 is a partial cross-sectional view schematically showing a part of the configuration of a sheet conveying device to which the sheet feeding device according to the sixth embodiment can be applied; 14 is a timing chart showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the pair of registration rollers and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 12 is a schematic diagram showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment; FIG. 5 is a view for explaining the relationship between the positions of a feeding roller, a pre-registration sensor, and registration rollers, and the feeding speed of the feeding roller and the conveying speed of the registration roller; 14 is a flowchart for explaining an example of a control operation in a thin paper mode according to the seventh embodiment; 14 is a flowchart for explaining an example of a control operation in a thin paper mode according to the seventh embodiment; FIG. 11 is a partial cross-sectional view schematically showing a part of the structure of a sheet conveying device including a sheet feeding device according to an eighth embodiment; 14 is a flowchart for explaining an example of a control operation in a thin paper mode performed by a control unit according to an eighth embodiment; A timing chart showing an example of operations of a pre-registration sensor, an optical sensor, and a pickup roller in the eighth embodiment. The schematic diagram which shows roughly the structure of optical sensor vicinity which concerns on 9th Embodiment. FIG. 2 is a schematic diagram schematically showing the configuration of the main parts of the sheet conveying device; 5 is a graph illustrating changes in contact pressure with respect to a sheet after the pickup roller is brought into contact with the sheet;

[First embodiment]
First, a sheet conveying device including a sheet feeding device according to the first embodiment of the present invention will be described.
FIG. 1 is a partial cross-sectional view schematically showing the configuration of a sheet conveying device (image reading device) including a sheet feeding device according to the first embodiment of the present invention.
FIG. 2 is a schematic diagram schematically showing the configuration of the main part of the sheet conveying device of FIG.

As shown in FIGS. 1 and 2, the sheet conveying device 200 of this embodiment includes a sheet take-in device (sheet feeding device) 101. As shown in FIG.
A plurality of sheets are stacked on a sheet stacking table (sheet stacking table) 1, and the sheet stacking table 1 is configured to be vertically movable. A sheet stacking table drive motor 2 moves the sheet stacking table 1 up and down. A sheet detection sensor 3 detects that a sheet stacked on the sheet stacking table 1 is at the sheet take-in position. A sheet stacking detection sensor 12 detects that sheets are stacked on the sheet stacking surface 1a of the sheet stacking table 1. FIG.

A pickup roller 4 (take-in means), which is an example of a sheet pickup unit, feeds a sheet on the sheet stacking table 1 from the sheet stacking table 1 . The pickup roller drive motor 5 rotates the pickup roller 4 in the sheet pickup direction (pickup direction). The state shown in FIG. 2 is a state in which the upper surface of the sheet is at the sheet take-in position, and when the pickup roller 4 is rotated, the take-in of the sheet starts. The pickup roller 4 can be driven by a drive unit (not shown) to the sheet take-in position in FIG. 2 and a retracted position (not shown) above the sheet take-in position. The pickup roller 4 is moved to the sheet fetching position when fetching the sheet, and is moved to the retracted position after the fetching is finished. A control unit 900 issues an instruction to rotate the pickup roller 4 and an instruction to move between the sheet take-in position and the retracted position. The control unit 900 has a CPU, ROM, RAM, etc. (not shown), and implements various controls by the CPU executing a program stored in the ROM. In addition, the pickup roller 4 plays an auxiliary role for reliably performing separation and feeding by a separation roller pair 42, which will be described later. If the sheet on the sheet stacking table 1 is sent to the nip portion of the separation roller pair 42 by the pickup roller 4, separation and feeding by the separation roller pair 42 can be reliably performed.

The feeding roller 6 is driven by a feeding motor 8 so as to rotate in a direction (feeding direction) for feeding the sheet downstream in the conveying direction. The separation roller 7 constantly receives a rotational force for pushing back the sheet toward the upstream side in the conveying direction from the separation motor 9 via a torque limiter (slip clutch) (not shown).

When there is one sheet between the feed roller 6 and the separation roller 7, the separation roller 7, which is transmitted by the above-described torque limiter, pushes back the sheet to the upstream side due to the upper limit value of the rotational force. The frictional force between the sheet fed downstream by 6 and the separation roller 7 overcomes the rotational force in the direction in which the sheet is fed downstream. Therefore, the separation roller 7 rotates following the feed roller 6 (co-rotates).

On the other hand, when there are a plurality of sheets between the feed roller 6 and the separation roller 7, the separation roller 7 receives the rotation of the roller shaft in the direction of pushing back the sheets to the upstream side, and the sheets other than the uppermost sheet are pushed downstream. to avoid being transported to

In this way, the feeding roller 6 feeds the sheet downstream and the separation roller 7 prevents the sheet from being conveyed downstream. Only the uppermost sheet is fed to the downstream side, and the other sheets are not conveyed to the downstream side. As a result, the overlapping sheets are separated and fed.

The feed roller 6 and the separation roller 7 constitute a pair of separation rollers 42 (sheet separation portion). In this embodiment, the separation roller pair 42 is used, but instead of the separation roller pair 42, a separation belt roller pair in which either the separation roller or the feeding roller is a belt may be used. . Further, the separation roller may be replaced with a separation pad, and by contacting the sheet, multiple sheets may be prevented from being conveyed to the downstream side. Alternatively, the separation roller 7 may be used so as to contact the sheet like a separation pad without being rotated.

Sheets stacked on the sheet stacking table 1 are separated one by one by the sheet pick-up section including the pickup roller 4, the feeding roller 6, the separation roller 7, and the like configured as described above, and the sheets are transferred to the inside of the sheet conveying device 200. It is captured.

Further, by providing the multi-feed detection sensor 30 at the position through which the separated sheets pass, it is possible to detect whether the sheets are separated one by one by the sheet separating section. In this embodiment, a detection device using an ultrasonic transmission/reception unit is used as the double-feeding detection sensor 30, and double-feeding can be detected based on the attenuation of ultrasonic waves between the transmission/reception units across the transport path. .

The conveying motor 10 conveys the separated sheet to the image reading position where the image of the sheet is read by the image reading sensors 14 and 15, and further conveys it to the discharging position. drive. Further, the conveying motor 10 drives each roller so that the sheet conveying speed can be changed according to settings such as the optimum speed for reading the sheet and the resolution of the sheet.

The nip gap adjustment motor 11 adjusts the gap between the feed roller 6 and the separation roller 7 or the pressing force with which the feed roller 6 presses against the separation roller 7 via the sheet. As a result, the gap or pressure contact force suitable for the thickness of the sheet is adjusted, and the sheet can be separated.

The registration clutch 19 transmits or interrupts the transmission of the rotational driving force of the transport motor 10 to the registration rollers 18 (sheet transport unit). By stopping the rotation of the registration roller pair composed of registration rollers 17 and 18, the leading edge of the sheet to be fed is brought into contact with the nip portion of the registration roller pair, thereby correcting the skew of the sheet.

A transport roller pair composed of transport rollers 20 and 21; a transport roller pair composed of transport rollers 22 and 23; The paper roller pair conveys the sheet to the discharge stacking section 44 . A paper discharge sensor 16 detects passage of the conveyed sheet. After the discharge sensor 16 detects the trailing edge of the sheet, a discharge brake is applied to slow down the rotation speed of the discharge roller pair 26, 27, thereby preventing the discharged sheet from jumping out and improving the discharge alignment. can be improved. Two guide plates, an upper guide plate 40 and a lower guide plate 41, guide sheets conveyed by the pair of separation rollers, the pair of registration rollers, the pairs of conveying rollers, and the pair of discharge rollers.

The pre-registration sensor 32 (feed detection means) is arranged upstream of the registration rollers 17 and 18 and detects the sheet being fed. The post-registration sensor 33 is arranged downstream of the registration roller pair composed of the registration rollers 17 and 18 and detects the conveyed sheet.

When the sheet is detected by the post-registration sensor 33, the controller 900 issues an image reading instruction to the image reading sensors 14 and 15, and the image of the conveyed sheet is read. Sheet images read by the image reading sensors 14 and 15 are transmitted to an external device such as an information processing device via an interface unit (not shown).

An example of the control operation of the pickup roller 4 in the thin paper mode (predetermined specific mode) performed by the control unit 900 of the first embodiment will be described below with reference to FIG.
FIG. 3 is a flowchart illustrating an example of control operations in the thin paper mode performed by the control unit 900 of the first embodiment. That is, the processing shown in this flowchart is realized by the CPU (not shown) of the control unit 900 executing a program stored in the ROM. Note that the thin paper mode can be set from an operation unit (not shown) or an information processing device (personal computer, etc.) communicably connected to the sheet conveying device 200 .

When starting the feeding operation in the thin paper mode, the control section 900 drives the feeding roller 6 and starts measuring time (measurement time (TIME)=0) (S101).
Next, in S102, the control unit 900 checks the pre-registration sensor 32 to determine whether the pre-registration sensor 32 has detected the leading edge of the sheet.

If it is determined that the pre-registration sensor 32 has not detected the leading edge of the sheet (No in S102), the control unit 900 advances the process to S103.
In S103, the control unit 900 determines whether or not the measurement time (TIME) has exceeded the specific time (TS). When determining that the measurement time (TIME) has not exceeded the specific time (TS) (No in S103), the control unit 900 returns the process to S102.

On the other hand, if it is determined that the measurement time (TIME) has exceeded the specific time (TS) (Yes in S103), that is, even if the measurement time (TIME) reaches the specific time (TS), the pre-registration sensor 32 detects the leading edge of the sheet. is not detected, the control unit 900 advances the process to S104

In S104, the control unit 900 moves the pickup roller 4 to the sheet take-in position and brings it into contact with the sheet.
Furthermore, in S105, the control unit 900 rotates the pickup roller 4 after a specific time (TD), which will be described later, has elapsed. This causes the pick-up roller 4 to feed the sheet to the feeding roller 6 .

Next, in S106, the control unit 900 starts measuring time again (measurement time (TIME)=0).
In S107, the control unit 900 checks the pre-registration sensor 32 to determine whether or not the pre-registration sensor 32 has detected the leading edge of the sheet.

If it is determined that the pre-registration sensor 32 has not detected the leading edge of the sheet (No in S107), the control unit 900 advances the process to S110.
In S110, the control unit 900 determines whether or not the measurement time (TIME) has exceeded the error time (TOUT). When determining that the measurement time (TIME) does not exceed the error time (TOUT) (No in S110), the control unit 900 returns the process to S107.

On the other hand, if it is determined that the measurement time (TIME) has exceeded the error time (TOUT) (Yes in S110), that is, even if the measurement time (TIME) reaches the error time (TOUT), the pre-registration sensor 32 detects the leading edge of the sheet. is not detected, the control unit 900 advances the process to S111. That is, even though the pickup roller 4 is moved to the take-in position and rotated, the leading edge of the sheet is not detected even when the error time is reached. are doing.
The control unit 900 moves the pickup roller 4 to the retracted position (S111), stops the rotation of the pickup roller 4 (S112), and ends the processing of this flowchart with an error.

On the other hand, if it is determined in S107 that the pre-registration sensor 32 has detected the leading edge of the sheet (Yes in S107), the control unit 900 advances the process to S108.
The control unit 900 moves the pickup roller 4 to the retracted position (S108), stops the rotation of the pickup roller 4 (S109), and proceeds to S113.

If it is determined in S102 that the pre-registration sensor 32 has detected the leading edge of the sheet (Yes in S102), the controller 900 proceeds to S113. In this case, the pickup roller 4 remains at the retracted position without moving to the contact position. That is, even if the pickup roller 4 is not driven, the leading edge of the sheet reaches the pre-registration sensor 32, and the sheet is pushed by the feeding roller 6 due to friction and static electricity generated between it and the previously fed sheet. After reaching the sensor 32, the previously fed sheet passes through the feeding roller 6, is transported by the feeding roller 6, and reaches at least the pre-registration sensor 32. FIG. At this time, the pickup roller 4 does not need to feed the sheet, and the pickup roller 4 is kept at the retracted position in order to prevent damage due to the contact of the pickup roller 4 with the sheet.

If it is determined in S102 or S107 that the pre-registration sensor 32 has detected the leading edge of the sheet, the control unit 900 issues an image reading instruction to the image reading sensors 14 and 15 in S113. A sheet reading operation is performed. During this time, the control unit 900 checks whether the pre-registration sensor 32 has detected the trailing edge of the sheet (S114). If it is determined that the pre-registration sensor 32 has not detected the trailing edge of the sheet (No in S114), the control section 900 returns the process to S113.

On the other hand, if it is determined that the pre-registration sensor 32 has detected the trailing edge of the sheet (Yes in S114), the control unit 900 advances the process to S115.
At S115, the control unit 900 checks whether or not there is a sheet on the sheet stacking tray. If it is determined that there is a sheet on the sheet stacking tray (Yes in S115), that is, if there is a next sheet, the control section 900 returns the process to S101.
On the other hand, if it is determined that there is no sheet on the sheet stacking tray (No in S115), that is, if there is no next sheet, the control section 900 terminates the processing of this flowchart. It should be noted that if the sheet is detected by the pre-registration sensor 32 even after waiting for a specific time (TS) or longer before the end, the process may proceed to S113, and if the sheet is not detected, the process may end. preferable.

FIG. 4 is a timing chart showing an example of operations of the pre-registration sensor 32 and the pickup roller 4 in the first embodiment.
FIG. 4A corresponds to an example in which the pre-registration sensor 32 does not detect the leading edge of the sheet even if the measurement time (TIME) exceeds the specific time (TS) (TIME>TS). In this case, the pickup roller 4 moves to the contact position and rotates after a specific time (TD) to feed the sheet to the feeding roller 6 . This prevents jamming caused by the contact pressure of the pickup roller 4 .

FIG. 4B corresponds to an example in which the pre-registration sensor 32 detects the leading edge of the sheet when the measurement time (TIME) is within the specific time (TS) (TIME<TS). In this case, the pickup roller 4 does not move to the contact position and remains at the retracted position. Therefore, the jam caused by the contact pressure of the pickup roller 4 does not occur. In FIG. 4B, the output of the pre-registration sensor 32 is turned off before counting the measurement time (TIME). is not driving and the output is OFF. On the other hand, when the pre-registration sensor 32 is constantly driven, the next sheet may reach the pre-registration sensor 32 before counting the measurement time (TIME). It is also assumed that ON is output. In that case, it may be confirmed at the start of counting the measurement time (TIME), and may be determined to be Yes in S102 of FIG.

In this embodiment, the specific period (TS) is set to 1 second, for example, in consideration of the reduction of the paper feeding time in the case of FIG. 4(a) and the certainty of sheet detection in the case of FIG. 4(b). have set.
Also, the specific time (TD) from when the pick-up roller contacts the sheet to when it rotates needs to be set longer than the contact pressure change time (TC) shown in FIG. have set.

In S108 and S109, S111 and S112 of FIG. 3 and FIG. 4, the pickup roller 4 is controlled to stop rotating after being moved to the retracted position, but the retracting operation and rotation stop may be performed at the same time. Alternatively, the order may be changed, and the retraction operation may be performed after the rotation is stopped. However, from the time the rotation is stopped until the sheet is retracted, the frictional force between the sheets increases due to the pressing pressure of the pickup roller 4, which makes it easier for the sheets to be entrained. The jam prevention effect is higher when both are performed at the same time.

As described above, in the first embodiment, after the pre-registration sensor detects the trailing edge of the previously separated and fed sheet, the pick-up roller to the position where it contacts the sheets stacked on the sheet stacking table, rotate the pickup roller after TD has elapsed, and prevent the pickup roller from contacting the sheet after the pre-registration sensor detects the leading edge of the sheet. It is characterized by retracting to a position and stopping rotation. With such a configuration, the sheet contact and the rotation start timing of the pickup roller are controlled as a countermeasure against jams when feeding thin paper or the like. Also, it is possible to prevent jams from occurring during paper feeding.

Note that the sheet conveying apparatus 200 of the present embodiment has a plain paper mode different from the above-described thin paper mode. computer) can be selected and set. Then, in a state where the plain paper mode different from the thin paper mode is set, the control unit 900 causes the pickup roller 4 to move the sheets stacked on the sheet stacking table 1 when continuously feeding a plurality of sheets. , the pickup roller 4 is rotated and stopped to continuously feed a plurality of sheets.

[Second embodiment]
Next, a sheet feeding device according to a second embodiment of the invention will be described.
In the sheet feeding apparatus 101 shown in FIGS. 1 and 2 described in the first embodiment, the sheet stacking table 1 moves up and down. Do not place it in contact with Therefore, it is necessary to always operate the pickup roller 4 in order to feed the first sheet.
In the second embodiment, a sheet feeding apparatus configured to feed the first sheet without operating the pickup roller 4 when the thin paper mode is applied will be described.

FIG. 5 is a partial cross-sectional view schematically showing the configuration of a sheet conveying device (image reading device) including a sheet feeding device according to the second embodiment of the present invention. Parts having the same functions as those of the sheet conveying apparatus shown in FIGS. 1 and 2 are given the same numbers, and explanations of individual parts are omitted.
The sheet conveying apparatus 300 shown in FIG. 5 differs greatly from the sheet conveying apparatus 200 shown in FIGS. 1 and 2 in that the sheet stacking table 1 does not move up and down, and the sheets stacked on the sheet stacking table 1 are fed in order from the bottom. and a point where the pick-up roller 4 contacts the sheet from below.

FIG. 5A shows a state in which the pickup roller 4 is lowered and is in a retracted position where it does not come into contact with the sheet.
FIG. 5(b) shows a state in which the pickup roller 4 is raised and is at the sheet take-in position where it contacts the sheet.
The sheet presser 50 is arranged at a position facing the pickup roller 4 and prevents the sheet from being pushed by the pickup roller 4 and lifted.

As shown in FIG. 5, when a sheet is placed on the sheet stacking table 1, the sheet falls toward the feed roller 6 due to its own weight, and the leading edge of the sheet often comes into contact with the feed roller 6. As shown in FIG. When feeding is started in the thin paper mode shown in FIGS. 3 and 4, the feeding roller 6 is rotated by the control of S101 to S103 in FIG. , can pass the feeding roller 6 and reach the pre-registration sensor 32 . If the sheet sticks to the sheet stacking table 1 due to static electricity or the like, the sheet may not fall off due to its own weight even if it is placed on the sheet stacking table 1 .

As described above, according to the second embodiment, the operation of the pickup roller 4 is started from the time of feeding the first sheet in the thin paper mode even for a device that feeds from below, such as the sheet conveying device of FIG. It is possible to reduce the amount of paper to a necessary minimum, and even if the sheet to be fed is thin paper or the like that is weak in stiffness, it is possible to suppress the occurrence of jams during feeding.

[Third Embodiment]
Next, a sheet feeding device according to a third embodiment of the invention will be described.
The hardware configuration of the sheet conveying apparatus including the sheet feeding apparatus according to the third embodiment of the present invention is the same as that of the sheet conveying apparatus 200 of the first embodiment shown in FIGS.

An example of the control operation of the pickup roller 4 in the thin paper mode performed by the control unit 900 of the third embodiment will be described below with reference to FIG.
FIG. 6 is a flowchart illustrating an example of control operations in the thin paper mode performed by the control unit 900 of the third embodiment. That is, the processing shown in this flowchart is realized by the CPU (not shown) of the control unit 900 executing a program stored in the ROM.

When the thin paper mode feeding operation is started, the control unit 900 of the third embodiment moves the pick-up roller 4 to the sheet take-in position and contacts the sheet (S204), and rotates the pick-up roller 4 (S205).
This point is different from the control example (FIG. 3) of the sheet feeding apparatus of the first and second embodiments.
In the first embodiment, even when feeding the first sheet, the pick roller 4 waits for a specific time (TS) without contact. In the third embodiment, the pickup roller 4 is operated to feed the first sheet without waiting for a specific time (TS).

An example in which such control is effective is when a sheet is placed at a position where the sheet stacking table is lowered in the sheet feeding apparatus shown in FIGS. In the sheet feeding apparatus shown in FIGS. 1 and 2, since the leading edge of the sheet is not placed in contact with the feeding roller 6, the pick-up roller 4 is operated to feed the first sheet. Become. Therefore, by operating the pickup roller 4 immediately when feeding the first sheet, the waiting time until the start of feeding the first sheet can be reduced.

[Fourth Embodiment]
Next, a sheet feeding device according to a fourth embodiment of the invention will be described.
The hardware configuration of the sheet conveying apparatus including the sheet feeding apparatus according to the fourth embodiment of the present invention is the same as that of the sheet conveying apparatus 200 of the first embodiment shown in FIGS.
FIG. 7 is a timing chart showing an example of operations of the pickup roller 4, the pre-registration sensor 32, and the pair of registration rollers 17 and 18 in the fourth embodiment.

FIG. 7A corresponds to an example in which the pre-registration sensor 32 does not detect the leading edge of the sheet even if the measurement time (TIME) exceeds the specific time (TS) (TIME>TS). In this case, the pickup roller 4 is moved to the contact position and rotated after a specific time (TD) has elapsed to feed the sheet to the feeding roller 6 . When the leading edge of the sheet reaches the pre-registration sensor 32, the pickup roller 4 is moved to the retracted position and stops rotating. Then, when the trailing edge of the sheet passes the pre-registration sensor 32, the pair of registration rollers 17 and 18 are stopped for a specific time (TF). As a result, it is possible to increase the interval between the sheet and the next sheet to be fed. After the registration rollers 17 and 18 are rotated after the specific time (TF) has passed, the pre-registration sensor 32 does not detect the leading edge of the sheet even after the specific time (TS) has passed (TIME > TS). 4 is brought into contact with the sheet and rotated to send the sheet to the feeding roller 6.

FIG. 7B corresponds to an example in which the pre-registration sensor 32 detects the leading edge of the sheet when the measurement time (TIME) is within the specific time (TS) (TIME<TS). In this case, the pickup roller 4 remains at the retracted position without being moved to the contact position. After the sheet passes the pre-registration sensor 32, the pair of registration rollers 17 and 18 are stopped for a specific time (TF). As a result, it is possible to increase the interval between the sheet and the next sheet to be fed. After the registration rollers 17 and 18 are rotated after the specific time (TF) has passed, the pre-registration sensor 32 detects the leading edge of the sheet when the measurement time (TIME) is within the specific time (TS) (TIME<TS). ing. Therefore, the jam caused by the contact pressure of the pickup roller 4 does not occur.

In both cases of FIGS. 7A and 7B, after the sheet passes the pre-registration sensor 32, the pair of registration rollers 17 and 18 are stopped for a specific time (TF) to feed the sheet. A conveyance interval can be provided between the sheet and the next sheet to be fed. As a result, even if the discharge speed slows down by applying the discharge brake using the discharge sensor 16 and the pair of discharge rollers 26 and 27 for the previously fed sheet, the next sheet can be fed. It is possible to open a sheet interval that is sufficient to prevent rear-end collision with the seat. Here, the specific time (TF) is set to 0.1 seconds, for example.

[Fifth Embodiment]
Next, a sheet feeding device according to a fifth embodiment of the invention will be described.
The hardware configuration of the sheet conveying apparatus including the sheet feeding apparatus according to the fifth embodiment of the present invention is the same as that of the sheet conveying apparatus 200 of the first embodiment shown in FIGS.
FIG. 8 is a timing chart showing an example of operations of the pickup roller 4, the pre-registration sensor 32, and the feeding roller 6 in the fifth embodiment.

FIG. 8A corresponds to an example in which the pre-registration sensor 32 does not detect the leading edge of the sheet even if the measurement time (TIME) exceeds the specific time (TS) (TIME>TS). In this case, the pickup roller 4 is moved to the contact position and rotated after a specific time (TD) has elapsed to feed the sheet to the feeding roller 6 . When the leading edge of the sheet reaches the pre-registration sensor 32, the pickup roller 4 is moved to the retracted position and stops rotating. Then, when the trailing edge of the sheet passes the pre-registration sensor 32, the feeding roller 6 (separation roller 7) is stopped for a specific time (TF). As a result, it is possible to increase the interval between the sheet and the next sheet to be fed. After the feeding roller 6 (separation roller 7) is rotated after the specified time (TF) has passed, the pre-registration sensor 32 does not detect the leading edge of the sheet even after the specified time (TS) has passed (TIME > TS). Therefore, the pickup roller 4 is brought into contact with the sheet and rotated to feed the sheet to the feeding roller 6 .

FIG. 8B corresponds to an example in which the pre-registration sensor 32 detects the leading edge of the sheet when the measurement time (TIME) is within the specific time (TS) (TIME<TS). In this case, the pickup roller 4 remains at the retracted position without being moved to the contact position. After the sheet passes the pre-registration sensor 32, the feed roller 6 (separation roller 7) is stopped for a specific time (TF). As a result, it is possible to increase the interval between the sheet and the next sheet to be fed. When the measurement time (TIME) is within the specific time (TS) after the feeding roller 6 (separation roller 7) is rotated after the specific time (TF) has passed (TIME < TS), the pre-registration sensor 32 Detecting the tip. Therefore, the jam caused by the contact pressure of the pickup roller 4 does not occur.

In both cases of FIGS. 8A and 8B, after the sheet passes the pre-registration sensor 32, the feeding roller 6 (separating roller 7) is stopped for a specific time (TF). A conveyance interval can be provided between the sheet to be fed and the sheet to be fed next. As a result, even if the discharge speed slows down by applying the discharge brake using the discharge sensor 16 and the pair of discharge rollers 26 and 27 for the previously fed sheet, the next sheet can be fed. It is possible to open a sheet interval that is sufficient to prevent rear-end collision with the seat. Here, the specific time (TF) is set to 0.1 seconds, for example.
The pair of registration rollers 17 and 18 may also be stopped/rotated at the timing of stopping/rotating the feeding roller 6 (separation roller 7).

Although the sheet conveying device of the present invention has been described in detail above, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the gist of the present invention.

As described above, according to each embodiment, documents that are weak and vulnerable to load, such as thin paper, slips, waste paper (history books), already wrinkled documents, already folded documents, torn documents, etc. Frictional force between sheets increases due to the contact pressure of the pick-up roller when feeding the sheets, and the sheets are dragged into the separation section, thereby reducing jamming. In other words, even if the sheet to be fed is thin paper or the like that is weak in stiffness, it is possible to prevent jams from occurring during feeding (prevent the occurrence of jams).
Note that the various rollers described above may be other rotating bodies such as belts.

[Sixth embodiment]
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, another embodiment in which driving of the feed roller 6 (separation roller 7) is turned ON/OFF will be described. The driving of the pair of registration rollers 17 and 18 may be turned on/off at the timing of turning on/off the driving of the feed roller 6 (separation roller 7), as shown in the above-described fourth embodiment. In the following description, even when the driving of the feeding roller 6 and the separation roller 7 is turned on/off, the driving of the feeding roller 6 is simply described as ON/OFF.
FIG. 9 is a partial cross-sectional view schematically showing a part of the structure of a sheet conveying device (image reading device) to which the sheet feeding device according to the sixth embodiment of the invention can be applied. The same symbols are attached to the same parts as those in FIG. 1 and the like.

In FIG. 9, the second pair of registration rollers composed of registration rollers 62 and 63 is arranged downstream of the first registration roller composed of registration rollers 17 and 18 . The in-registration sensor 61 is arranged downstream of the first pair of registration rollers (17, 18) and upstream of the second pair of registration rollers (62, 63) to detect the sheet being conveyed. The post-registration sensor 33 is arranged on the downstream side of the second pair of registration rollers (62, 63) and detects the conveyed sheet.

FIG. 10 is a timing chart showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the registration roller pair, and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment.
11 to 15 are schematic diagrams showing an example of the relationship between the operations of the pickup roller, the feeding roller, and the pair of registration rollers and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment. The same reference numerals are assigned to the same states as (0) to (11) in FIG. A series of flows will be described below.

First, the feed roller 6 and registration rollers (17, 18, 62, 63) are driven (Fig. 11(0)), the pickup roller 4 is moved to the contact position (Fig. 11(1)), and a specific time ( TD), rotates after the passage of time ((2) in FIG. 11), and feeds the sheet to the feeding roller 6 . When the leading edge of the sheet reaches the pre-registration sensor 32 (FIG. 11(3)), the pickup roller 4 is moved to the retracted position (FIG. 12(4)) and stops rotating (FIG. 12(4)'). When the leading edge of the sheet reaches the in-registration sensor 61 ((5) in FIG. 12), the feeding roller 6 is stopped ((6) in FIG. 12). Then, the trailing edge of the sheet passes the pre-registration sensor 32 (FIG. 13(7)) (this time is defined as "t0"), and after t1 elapses (FIG. 13(8)), the feeding roller 6 is rotated. Thereafter, the trailing edge of the sheet passes through the in-registration sensor 61 (FIG. 13(8)'). Also, after t2 (preferably t2>t1+L/V1) has elapsed from time t0 (preferably t2>t1+L/V1) (FIG. 13(9)), the pickup roller 4 is moved to the contact position (FIG. 13(10)), and a specific time (TD) After the passage of time, it rotates ((11) in FIG. 14) and feeds the next sheet to the feeding roller 6 . As shown in FIG. 18, which will be described later, if the sheet conveying speed by the feeding roller 6 is V1, and the distance from the feeding roller 6 to the pre-registration sensor 32 is L1, t2 is preferably "t2>t1 +L/V1”.

Note that when the leading edge of the next sheet is detected by the pre-registration sensor 32 during the period from the time t1 to the time t2 (from (8) to (9)), the pickup roller 4 is moved to the contact position. Instead, it waits until the leading edge of the sheet reaches the in-registration sensor 61 as shown in FIG. 12(5). This example will be described in detail below with reference to FIGS. 15 to 17. FIG.
15 to 17 are schematic diagrams showing an example of the relationship between the operations of the pickup roller, the feed roller, and the pair of registration rollers and the detection states of the pre-registration sensor and the during-registration sensor in the sixth embodiment. This corresponds to the case where the leading edge of the next sheet is detected by the pre-registration sensor 32 during this period.

11 to 14 described above, as shown in FIGS. )), the pickup roller 4 is moved to the contact position ((1) in FIG. 15), rotated after a specific time (TD) has passed ((2) in FIG. 15), and the first sheet is sent to the feeding roller 6. . When the leading edge of the first sheet reaches the pre-registration sensor 32 (FIG. 15(3)), the pickup roller 4 is moved to the retracted position (FIG. 16(4)) and stops rotating (FIG. 16(4)'). . In this example, as shown in FIG. 16, at point (4), the second sheet is fed along with the first sheet due to friction between the sheets, static electricity, etc., and the feed roller Corresponds to the case where the nip portion of 6 is reached. However, the separation roller 7 separates the first sheet and the second sheet so that they are not double-fed. After that, when the leading edge of the first sheet reaches the in-registration sensor 61 (FIG. 16(5)), the feeding roller 6 is stopped (FIG. 16(6)). Further, the trailing edge of the first sheet passes the pre-registration sensor 32 ((7) in FIG. 17) (this time is defined as "t0"), and after t1 ((8) in FIG. 17), the feeding roller 6 to rotate. As a result, the feeding roller 6 starts feeding the second sheet. After that, the trailing edge of the first sheet passes through the in-registration sensor 61 (FIG. 17(8)'). Furthermore, in the case of this example, the leading edge of the second sheet is detected by the pre-registration sensor 32 before t2 elapses from time t0 (FIG. 17(8)''). In this case, as described above, the pickup roller 4 is not moved to the contact position, and the operation is controlled to wait until the leading edge of the second sheet reaches the in-registration sensor 61 in (FIG. 17(5)). do.

As described above, as shown in FIGS. 10, 11 to 14, and 15 to 17, a predetermined time (t1) has elapsed after the sheet passed the mid-registration sensor 61 and the trailing edge of the sheet passed the pre-registration sensor 32. By stopping the feeding roller 6 until the sheet is fed, it is possible to widen the feeding interval between the sheet to be fed first and the sheet to be fed next. As a result, even when the discharge speed of the previously fed sheet is slowed down, it is possible to provide a sheet interval sufficient to prevent rear-end collision with the next fed sheet. In this case, this example is just an example. For example, as the timing to stop the feeding roller 6, the feeding roller 6 may be stopped after waiting a predetermined time from the time when the leading edge of the sheet reaches the sensor 61 during registration. The feeding roller 6 should be stopped at the timing when the desired sheet interval is obtained.

In the case of a configuration in which the feeding roller 6 is not stopped, the time t2 from when the trailing edge of the sheet passes the pre-registration sensor 32 to when the pickup roller 4 starts moving to the contact position is t2', for example, "t2'>(L −V1×(L/V2))/V1”, which can be slightly shorter than “t2>t1+L/V1” in the case of the configuration in which the feeding roller 6 is stopped.
FIG. 18 is a diagram for explaining the relationship between the positions of the feeding roller 6, the pre-registration sensor 32 , the registration rollers 17 and 18, the feeding speed of the feeding roller 6, and the conveying speed of the registration rollers.

When the feed roller 6 is constantly rotating, the minimum waiting time until the pickup roller 4 is lowered to the subsequent sheet is as follows.
When the second sheet has reached the feeding roller 6 along with the feeding of the first sheet, the second sheet is detected when the first sheet passes the pre-registration sensor 33. exists at a position advanced by "V1×(L/V2)" from the position of the feeding roller 6. Therefore, if you wait for the time "(L-V1×(L/V2))/V1" for the second sheet to be fed from that position to the position of the pre-registration sensor 33 at the feeding speed V1, the second sheet should reach the pre-registration sensor 33 . Therefore, this time “(L−V1×(L/V2))/V1” can be the minimum waiting time until the pickup roller 4 is lowered to the subsequent sheet.

[Seventh embodiment]
In each of the above-described embodiments, a configuration has been described in which the pickup roller 4 is moved to the contact position, and after waiting for the specific time (TD), the pickup roller 4 is rotated. However, when the pickup roller 4 moves to the contact position and contacts the sheet, the sheet may be pushed out in the conveying direction and reach the feeding roller 6 . For example, in the example shown in FIG. 9, the pickup roller 4 rotates about the center of rotation 64 of the pick provided downstream of the pickup roller 4 in the conveying direction, so the pickup roller 4 contacts the sheet. The configuration is such that the sheet can be easily pushed out in the conveying direction when it is pressed. Since the sheet pushed out in the conveying direction and brought into contact with the feed roller 6 is conveyed by the feed roller 6, it is not necessary to rotate the pickup roller 4 to send the sheet. In this embodiment, in such a case, the pickup roller 4 is configured to be returned to the standby position without being rotated. This embodiment will be described in detail below.

19 and 20 are flowcharts for explaining an example of the control operation in the thin paper mode in the seventh embodiment. The processes shown in these flowcharts are realized by the CPU (not shown) of the control unit 900 executing a program stored in the ROM.

First, the flowchart of FIG. 19 will be described. In FIG. 19, the same steps as in FIG. 3 are given the same step numbers, and description thereof will be omitted.
After moving the pickup roller 4 to the sheet take-in position and bringing it into contact with the sheet in S104, the control unit 900 starts measuring time (measurement time (TIME)=0) in S116.
Next, in S117, the control unit 900 checks the pre-registration sensor 32 to determine whether the pre-registration sensor 32 has detected the leading edge of the sheet. When it is determined that the pre-registration sensor 32 has detected the leading edge of the sheet (Yes in S117), the control unit 900 determines that the sheet is pushed out by the contact of the pickup roller 4 and fed by the feeding roller 6, Move to S108.

On the other hand, if it is determined that the pre-registration sensor 32 has not detected the leading edge of the sheet (No in S117), the control unit 900 advances the process to S118.
In S118, the control unit 900 determines whether or not the measurement time (TIME) has exceeded a specific time (TD), which will be described later. When determining that the measurement time (TIME) has not exceeded the specific time (TD) (No in S118), the control section 900 returns the process to S117.

On the other hand, if it is determined that the measurement time (TIME) has exceeded the specific time (TD) (Yes in S118), that is, even if the measurement time (TIME) reaches the specific time (TD), the pre-registration sensor 32 detects the leading edge of the sheet. is not detected, the control unit 900 advances the process to S119.
At S119, the control unit 900 rotates the pickup roller 4. FIG. This causes the pick-up roller 4 to feed the sheet to the feeding roller 6 .
Since the processing is the same as that in FIG. 3, the description is omitted.

Next, the flowchart of FIG. 20 will be described. In FIG. 20, the same steps as in FIG. 6 are given the same step numbers, and description thereof will be omitted.
Further, S216 to S219 in FIG. 20 are the same as S116 to S119 in FIG. 19, so description thereof will be omitted.

In the flowchart shown in FIG. 20, when thin paper feeding is started, the pickup roller 4 is moved to the fetching position immediately after the start of thin paper feeding for the first sheet. It is also possible to detect the leading edge of the sheet by the pre-registration sensor 32 without rotating the pickup roller 4 .

With the above processing, when the pickup roller 4 moves to the contact position and contacts the sheet and the sheet is pushed out in the conveying direction and reaches the feeding roller 6, the pickup roller 4 in contact with the sheet is rotated. In addition to omitting unnecessary operations such as this, it is possible to suppress damage to sheets that are vulnerable to loads.

[Eighth Embodiment]
Next, an eighth embodiment of the invention will be described. In the eighth embodiment, an embodiment in which an optical sensor is used to detect movement of a sheet on the sheet stacking table 1 will be described. As the optical sensor, for example, a sensor capable of detecting the amount of movement of the facing surface using an area image sensor can be applied. This optical sensor can detect the movement amount including the movement direction and movement speed of the facing surface by capturing an image of the facing surface at predetermined time intervals and calculating the movement amount of the feature point in the image.
FIG. 21 is a partial cross-sectional view schematically showing a part of the configuration of a sheet conveying device (image reading device) including the sheet feeding device according to the eighth embodiment of the invention. The same symbols are attached to the same parts as those in FIG. 1 and the like.

In the sheet conveying apparatus of the eighth embodiment, as shown in FIG. 21, at a position facing the sheet stacking table 1, an optical sensor 111 capable of detecting the amount of movement of the conveyed sheet is mounted on a substrate (optical sensor 111). A substrate 100) is attached parallel to the sheet stacking table 1. As shown in FIG. That is, the imaging surface of the optical sensor 111 is attached so as to be substantially parallel to the surface (facing surface) of the sheet stacking table 1 . Here, as the optical sensor 111, an imaging device such as an area image sensor (for example, a laser light source tracking sensor) is used. In the light source unit 102, a light source unit composed of a semiconductor laser or an LED emits light, and a light receiving unit receives and photoelectrically converts the light emitted by the light source unit reflected on the surface of the sheet. A tracking sensor with a laser light source enables accurate tracking by illuminating very fine details of an imaging surface with a laser, and is used in, for example, a mouse. The imaging surface of the optical sensor 111 being parallel to the surface of the sheet stacking table 1 means that the optical sensor board 100 on which the optical sensor 111 is mounted is parallel to the surface of the sheet stacking table 1 .

In the present embodiment, the optical sensor 111 is used as an imaging element to acquire an image of the conveyed sheet, and the movement of the sheet is detected by detecting the amount of movement based on the image information. The optical sensor 111 is arranged at a predetermined distance from the imaging reference plane in the conveying path along which the sheet is conveyed. The imaging reference plane is a plane that faces the optical sensor 111, which is an imaging element, and serves as a reference for imaging by the optical sensor 111. In the present embodiment, the conveyance path (sheet stacking table 1 ) is defined as the imaging reference plane. However, when the sheet is placed on the sheet stacking table 1, the position corresponding to the surface of the conveyed sheet becomes the imaging reference plane. That is, the surface of the sheet stacking table 1 at the uppermost position in the lifting range of the sheet stacking table 1 when feeding the sheet substantially coincides with the imaging reference plane. By separating the optical sensor 111 from the imaging reference plane by a predetermined distance D (FIG. 21), images of the sheet can be acquired at appropriate intervals regardless of the type of sheet or the position where the optical sensor 111 is arranged. Therefore, as the optical sensor 111, it is preferable to use a sensor that can focus on the sheet separated by the predetermined distance D. FIG. In this embodiment, the optical sensor 111 is arranged apart from the imaging reference plane by a predetermined distance D of about 20 mm to 30 mm.

Also, the optical sensor 111 detects the height from the conveying path of the paper feed unit section 113 which is composed of the pickup roller 4 and the pickup roller drive motor 5, the feed roller 6 and the nip gap adjustment motor 11, the separation roller 7 and the separation motor 9. It is positioned lower than the height h (Fig. 21). The optical sensor 111 can be arranged without affecting the size of the housing in the height direction in the configuration of the paper feeding unit.

Further, the optical sensor 111 used in the present embodiment generally detects the image of the original when the light receiving surface of the optical sensor and the original are parallel to each other, compared to when the light receiving surface and the original are tilted. It has a characteristic that it can follow even a region where the moving speed of is faster. Therefore, as described above, the imaging surface (light receiving surface) of the optical sensor 111 and the surface of the document are arranged so as to be substantially parallel to each other. However, depending on the type and characteristics of the optical sensor 111 to be used or the limitations of the device, the imaging surface (light receiving surface) of the optical sensor 111 and the surface of the document may be arranged so as not to be substantially parallel.

In this embodiment, the optical sensor 111 acquires an image of the sheet, and the IC provided on the substrate 100 on which the optical sensor 111 is mounted images at predetermined time intervals (or based on predetermined movement amount intervals). Image) is compared to determine the movement amount of the sheet. An IC mounted on the substrate 100 operates as a movement amount detection unit. However, the image acquired by the optical sensor 111 may be transmitted to an external device, and the movement amount may be determined on the external device. In this case, it can be said that the movement amount detection unit includes the external device. In that case, the sheet conveying apparatus in this embodiment is configured including the part that determines the amount of movement in the external apparatus.

As shown in FIG. 21, the sheet stacking table 1 is provided with movable regulating members 51 at both ends in the width direction with respect to the conveying direction to regulate the width of the sheet. By moving the regulating member 51 in the width direction to match the width of the sheet to be conveyed, it is possible to prevent the sheet from skewing during conveyance. Note that the optical sensor 111 may be attached to the regulating member 51 or may be attached to the exterior of the main body.

The above-described movement amount detection unit obtains an area image with the optical sensor 111, converts it into a digital signal with an A/D conversion unit (not shown), and sequentially compares the obtained images with the object to be imaged (this embodiment). In the case of the form, the movement amount or movement direction of the "sheet") is detected. In the present embodiment, a single optical sensor can detect the conveying state of a sheet, so the apparatus can be provided without increasing the size and cost of the apparatus.

Here, assuming that the sheet stack placed on the sheet stacking table 1 is continuously fed one by one, the positions of the sheets conveyed to the sheet feeding unit section 113 will be described next.
In FIG. 21, the sheet that should have been placed at the position indicated by the one-dot chain line is placed at a higher position than the placed position due to the frictional force generated between the surfaces of the immediately preceding sheet and the next sheet when the immediately preceding sheet is conveyed. It may move to the paper feed unit section 113 side (dotted line position). In that case, if at least a part of the sheet of the minimum size that can be conveyed by this sheet conveying apparatus is imaged in the area L (FIG. 21) imaged by the optical sensor 111, the optical sensor Movement of the sheet can be detected by 111 .

In FIG. 21, the minimum size sheet at the position indicated by the dotted line, that is, the position where the leading edge comes into contact with the conveying path just before the separation roller pair 42 after entering the paper feed unit 113 due to friction with the preceding sheet. The optical sensor 111 is arranged at a position where the trailing edge of the minimum size sheet at 1 is included in the imaging area L of the optical sensor 111 . Note that the minimum size sheet varies depending on the device, but may be a business card size or the like. For example, in the case of a sheet conveying device capable of conveying a business card-sized sheet, the optical sensor 111 is arranged at a position close to the pickup roller 4, and depending on the case, is upstream of the separating roller pair (6, 7) in the conveying direction. It may be provided inside the sheet feeding unit section 113 on the side. For example, an optical sensor 111 may be provided at the location shown as 65 in FIG. That is, when the sheet bundle placed on the sheet stacking table 1 is continuously conveyed to the sheet feed port provided upstream of the conveying path, the optical sensor 111 detects that the leading edge of the sheet on the conveying path is the nip of the separation roller pair. By providing the optical sensor 111 at a position where the distance to the position where it abuts on the part is shorter than the length of the minimum size sheet, that is, at a position where the trailing edge of the sheet indicated by the dotted line in FIG. It is possible to detect the amount of movement by imaging the trailing edge of the sheet. As a specific arrangement of the optical sensor 111, it is slightly upstream of the tip of the sheet stacking table 1 where the sheets are stacked. In other words, it is a position facing the sheet stacking table 1 on the front end side of the sheet stacking table 1 . More preferably, the optical sensor 111 is arranged upstream of the pickup roller 4 as shown in FIG. By arranging the optical sensor 111 lower than the height of the paper feeding unit section 113 having the pickup roller 4 and the feeding roller 6, it is possible to suppress an increase in the size of the apparatus main body.

An example of the control operation of the pickup roller 4 performed by the control unit 900 of the eighth embodiment will be described below with reference to FIG.
FIG. 22 is a flowchart illustrating an example of control operations in the thin paper mode performed by the control unit 900 of the eighth embodiment. That is, the processing shown in this flowchart is realized by the CPU (not shown) of the control unit 900 executing a program stored in the ROM. Note that the thin paper mode can be set from an operation unit (not shown) or an information processing device (personal computer, etc.) communicably connected to the sheet conveying device 200 .

When starting the feeding operation in the thin paper mode, the control section 900 drives the feeding roller 6 and starts measuring time (measurement time (TIME)=0) (S1).
Next, in S2, the control unit 900 determines whether or not the optical sensor 111 has detected movement of the sheet.

If it is determined that sheet movement has not been detected (No in S2), the control unit 900 advances the process to S3.
In S3, the control section 900 determines whether or not the measurement time (TIME) has exceeded the specific time (TS). When determining that the measurement time (TIME) has not exceeded the specific time (TS) (No in S3), the control unit 900 returns the process to S2.

On the other hand, if it is determined that the measurement time (TIME) has exceeded the specific time (TS) (Yes in S3), that is, even if the measurement time (TIME) reaches the specific time (TS), the optical sensor 111 does not move the sheet. is not detected, the control unit 900 advances the process to S4

In S4, the control unit 900 moves the pickup roller 4 to the sheet take-in position, contacts the sheet, and rotates it. This causes the pick-up roller 4 to feed the sheet to the feeding roller 6 . In the case of the thin paper mode, the pickup roller 4 is rotated after a specific time (TD) has passed after contact with the sheet, but in the non-thin paper mode, the pickup roller 4 may be rotated before contact with the sheet. Although not shown, as described in the seventh embodiment, when the optical sensor 111 detects the sheet movement or the pre-registration sensor 32 detects the leading edge of the sheet before the specific time (TD) elapses, Alternatively, the pickup roller 4 may be returned to the retracted position without rotating.

Next, in S5, the control unit 900 starts measuring time again (measurement time (TIME)=0).
In S6, the control unit 900 determines whether the optical sensor 111 has detected movement of the sheet.

If it is determined that sheet movement has not been detected (No in S6), the control unit 900 advances the process to S7.
In S7, the control unit 900 determines whether or not the measurement time (TIME) has exceeded the error time (TE). When determining that the measurement time (TIME) does not exceed the error time (TE) (No in S7), the control section 900 returns the process to S6.

On the other hand, if it is determined that the measurement time (TIME) has exceeded the error time (TE) (Yes in S7), the control section 900 advances the process to S8. That is, even though the pickup roller 4 is moved to the take-in position and rotated, the leading edge of the sheet is not detected even when the error time is reached. do.
In S8, the control unit 900 moves the pickup roller 4 to the retracted position and stops it, and ends the processing of this flowchart with an error.

On the other hand, if it is determined in S6 that movement of the sheet has been detected (Yes in S6), the control unit 900 advances the process to S9.
In S9, the control unit 900 checks the pre-registration sensor 32 to determine whether the pre-registration sensor 32 has detected the leading edge of the sheet. If it is determined that the pre-registration sensor 32 has not detected the leading edge of the sheet (No in S9), the control section 900 repeats the determination process of S9. At this time, if the measurement time (TIME) detects the error time (TE), the process may be configured to proceed to S8.
On the other hand, if it is determined that the pre-registration sensor 32 has detected the leading edge of the sheet (Yes in S9), the controller 900 proceeds to S10.
In S10, the control unit 900 moves the pickup roller 4 to the retracted position and stops, and proceeds to S12.

If it is determined in S2 that the movement of the sheet has been detected (Yes in S2), the control unit 900 does not move the pickup roller 4 to the sheet take-in position and leaves it at the retracted position, and proceeds to S11. proceed.
In S11, the control unit 900 checks the pre-registration sensor 32 to determine whether the pre-registration sensor 32 has detected the leading edge of the sheet. If it is determined that the pre-registration sensor 32 has not detected the leading edge of the sheet (No in S11), the control section 900 repeats the determination process of S11. At this time, if the measurement time (TIME) detects the error time (TE), the process may be configured to proceed to S8.
On the other hand, if it is determined that the pre-registration sensor 32 has detected the leading edge of the sheet (Yes in S11), the controller 900 proceeds to S12.

If it is determined in S9 or S11 that the pre-registration sensor 32 has detected the leading edge of the sheet, the control unit 900 issues an image reading instruction to the image reading sensors 14 and 15 in S12. A sheet reading operation is performed. During this time, the control unit 900 determines whether the pre-registration sensor 32 has detected the trailing edge of the sheet (S13). If it is determined that the pre-registration sensor 32 has not detected the trailing edge of the sheet (No in S13), the control section 900 returns the process to S12.

On the other hand, if it is determined that the pre-registration sensor 32 has detected the trailing edge of the sheet (Yes in S13), the control section 900 advances the process to S14.
At S14, the control unit 900 checks whether or not there are sheets on the sheet stacking table 1. FIG. If it is determined that there is a sheet on the sheet stacking table 1 (Yes in S14), that is, if there is a next sheet, the control unit 900 returns the process to S1 and waits for the next sheet to be fed. Start measurement.
On the other hand, if it is determined that there is no sheet on the sheet stacking tray 1 (No in S14), that is, if there is no next sheet, the control section 900 ends the processing of this flowchart.

FIG. 23 is a timing chart showing an example of operations of the pre-registration sensor 32, the optical sensor 111, and the pickup roller 4 in the eighth embodiment. Note that the ON state of the optical sensor 111 means that the sheet movement amount input from the optical sensor 111 to the control unit 900 exceeds the threshold value. On the other hand, turning off the optical sensor 111 means that the sheet movement amount input from the optical sensor 111 to the control unit 900 does not exceed the threshold value. In addition to exceeding the above threshold, for example, moving in the same moving direction continuously for a predetermined time (the amount of movement in one direction within a predetermined time is equal to or greater than a predetermined value), etc., can be set as ON of the optical sensor 111. good too.

FIG. 23A corresponds to an example in which the optical sensor 111 does not detect the movement of the sheet even if the measurement time (TIME) exceeds the predetermined time (TS) (TIME>TS). In this case, after the pickup roller 4 is moved (lowered) to the contact position, the pickup roller 4 is rotated to send the sheet to the nip portion of the separation roller pair. This prevents jamming caused by the contact pressure of the pickup roller 4 . In FIG. 23(a), the illustration of the rotational drive timing of the pickup roller 4 is omitted, and the display is simplified so that the optical sensor 111 is turned on when the pickup roller 4 is lowered.

FIG. 23B corresponds to an example in which the optical sensor 111 detects movement of the sheet when the measurement time (TIME) is within the predetermined time (TS) (TIME<TS). In this case, the pickup roller 4 does not move (lower) to the contact position and stays (raises) at the retracted position. Therefore, jam caused by the pickup roller 4 does not occur.

By arranging the optical sensor 111 upstream of the feed roller 6 and the separation roller 7 in the conveying path, it is possible to shorten the time until it is determined whether or not to lower the pickup roller 4 . For example, as shown in FIG. 21, an optical sensor 111 for detecting the amount of sheet movement for determining whether or not to lower the pickup roller 4 is arranged upstream of the pickup roller 4 which is the most upstream of the conveying path. By doing so, it is possible to shorten the time until it is determined whether or not to lower the pickup roller 4 . In other words, if the optical sensor 111 cannot detect the movement of the sheet even after the predetermined time has passed, the pickup roller 4 can be quickly lowered. As a result, it is possible to suppress a decrease in the number of sheets that can be conveyed within a predetermined time.

As an example, when the trailing edge of the preceding sheet passes the pre-registration sensor 32 while the minimum size sheet stacked on the sheet stacking table 1 is separated by the separation roller 7, the optical sensor 111 detects the minimum size sheet. By arranging the sheet at a position where the movement amount of the preceding sheet can be detected, it is possible to determine whether or not the movement of the sheet has been detected by the optical sensor 111 when the trailing edge of the preceding sheet passes the pre-registration sensor 32. , it is also possible to eliminate the time until it is determined whether or not the pickup roller 4 should be lowered.

Further, as described above, the optical sensor 111 can detect the rotation of the sheet by detecting the movement amount of the sheet. Therefore, the movement amount of the sheet can be detected by the optical sensor 111, and the conveyance state of the sheet, that is, the sheet conveyance failure can be detected from the detected movement amount of the sheet. The transport failure referred to here means that the sheet is skewed at the time the document is transported by the document transport unit (for example, the feeding roller 6), or the sheet is bound by the separation roller 7 by stapling or the like. This refers to a situation in which the sheet is conveyed and the separation action works, but the sheet cannot actually be separated.

In either case, the sheet will be damaged if the sheet is continued to be conveyed in the state where the conveyance failure has occurred. For this reason, as in the present embodiment, the optical sensor 111 is arranged on the upstream side of the conveying path from the feeding roller 6 and the separating roller 7, and the conveying defect is detected at an early stage and the conveying control is performed. damage can be prevented. Specifically, when a defective conveyance is detected, control such as stopping or decelerating conveyance by the sheet conveying unit is performed. In addition, the user may be notified of the detection of a transport failure.

As described above, the optical sensor 111 is arranged on the upstream side of the conveying path from the feeding roller 6 in the apparatus main body. In particular, in FIG. 21, the optical sensor 111 is arranged on the upstream side of the transport path from the pickup roller 4 in the apparatus main body. By arranging it at this position, the occurrence of the defect can be detected early by the optical sensor 111 when the transport defect occurs immediately after the start of sheet transport. In addition, since it is located near the pickup roller 4 and the feeding roller 6, it is possible to detect the movement of the original even for a small original.
In addition, since the detection of the conveying state of the sheet and the determination of the vertical movement of the pickup roller 4 are performed by one optical sensor 111, the apparatus can be provided without increasing the size and cost of the apparatus.

According to the present embodiment, wear of the pickup roller can be suppressed by minimizing the number of times the pickup roller conveys the sheet. Furthermore, by arranging the sheet movement detection section on the upstream side of the separation feeding section, it is possible to suppress a decrease in the number of sheets that can be conveyed within a predetermined time. Also, it is possible to make it difficult for jams caused by the pickup roller to occur.

[Ninth Embodiment]
The schematic configuration is similar to that of the eighth embodiment described above. Therefore, the details of the ninth embodiment will be described only for the parts that differ from the eighth embodiment.
FIG. 24 is a schematic diagram schematically showing the configuration around the optical sensor 111 according to the ninth embodiment.
In the ninth embodiment, as shown in FIG. 24, a light source section 102 is provided separately from the optical sensor 111 for the purpose of increasing the amount of light received by the optical sensor 111 . A light source unit 102 is a light source unit configured by a semiconductor laser or an LED. In this embodiment, the light source unit 102 is provided as a device separate from the optical sensor 111, but the optical sensor 111 and the light source unit 102 may be configured as one device.

In the present embodiment, apart from the optical sensor 111 in which the light-emitting portion and the light-receiving portion are incorporated as a unit, more specifically, the optical sensor 111 is arranged so that light can be emitted from a direction different from the irradiation direction from the optical sensor 111. Light emitted by the light source unit 102 is reflected on the surface of the sheet portion. When this reflected light is incident on the optical sensor 111, the optical sensor captures an image of the sheet surface. Further, the lens 103 may be arranged in front of the optical sensor 111 to converge light on the optical sensor 111 more efficiently.

As described above, according to the ninth embodiment, a sheet conveying apparatus can be provided without increasing the size and cost of the apparatus by detecting the sheet conveying state with one optical sensor.

Instead of providing the optical sensor 111, the pre-registration sensor 32 may be provided immediately after the nip position of the separation roller pair (7, 8).
Further, in each of the above-described embodiments, a configuration has been described in which the presence or absence of contact of the pickup roller 4 with the sheet on the document stacking table 1 is switched by moving the standby position and the contact position of the pickup roller 4 (by raising and lowering). However, instead of raising and lowering (moving) the pickup roller 4, the document stacking table 1 may be raised and lowered to switch between the presence or absence of contact between the pickup roller 4 and the sheet on the document stacking table 1. FIG.
Although the sheet conveying device of the present invention has been described in detail above, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the gist of the present invention.

As described above, according to each of the embodiments, even if the sheet to be fed is thin paper or the like with low stiffness, it is possible to prevent jams from occurring during feeding.

The configuration and content of the various data described above are not limited to this, and may be configured in various configurations and content according to the application and purpose.
Although one embodiment has been described above, the present invention can be embodied as, for example, a system, device, method, program, storage medium, or the like. Specifically, it may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of a single device.
In addition, the present invention includes all configurations obtained by combining the above embodiments.

[Other embodiments]
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.
Moreover, the present invention may be applied to a system composed of a plurality of devices or to an apparatus composed of one device.
The present invention is not limited to the above embodiments, and various modifications (including organic combinations of each embodiment) are possible based on the gist of the present invention, and they are excluded from the scope of the present invention. isn't it. In other words, the present invention includes all configurations obtained by combining each of the above-described embodiments and modifications thereof.

1 sheet stacker
4 Pickup roller
6 Feed roller
7 Separation roller
17, 18, 62, 63 Registrar
32 Pre-registration sensor
61 Resist sensor
100 Optical sensor board
111 optical sensor
113 Paper feed unit

Claims (16)

a retrieving means for retrieving the sheet by rotating while in contact with the sheet stacked on the sheet stacking table;
feeding means for feeding the taken-in sheet in the feeding direction;
a detecting means for detecting the sheet being fed;
In a predetermined first mode, when a plurality of sheets are continuously fed, the next sheet is not fed even if the first specific time elapses after the detecting means detects the trailing edge of the previously fed sheet. is not detected, the fetching means is brought into contact with the sheets stacked on the sheet stacking table, and after a second specific time has elapsed, the fetching means is rotated in the fetching direction, and the detection is made. control means for controlling the fetching means to separate from the sheet after the means has detected the leading edge of the sheet;
has
The second specific time is longer than a preset contact pressure change time during which the preset contact pressure on the sheet changes by bringing the fetching means into contact with the sheet stacked on the sheet stacking table. also long,
When the detection means detects the leading edge of the sheet before the second specific time elapses, the control means controls the movement of the fetching means without rotating the fetching means in contact with the sheet. from the sheet
A sheet feeding device characterized by: 2. A sheet feeding apparatus according to claim 1, wherein said control means drives said feeding means in the feeding direction while waiting for said first specific time in said first mode. In the case of continuously feeding a plurality of sheets in the first mode, and in the case of feeding the first sheet after starting the feeding operation, the control means controls the above-described 2. When the detection means does not detect the leading edge of the sheet even after a first specific time elapses, the fetching means is brought into contact with the sheet stacked on the sheet stacking table. 3. The sheet feeding device according to 2. When the plurality of sheets are placed at the position where the sheet stacking table is lowered and the plurality of sheets are continuously fed in the first mode, the control means places the first sheet after starting the feeding operation. In the case of feeding (1), the fetching means is brought into contact with the sheets stacked on the sheet stacking table without waiting for the passage of the first specific time after the start of the feeding operation. 3. The sheet feeding device according to claim 1 or 2, characterized by: When a plurality of sheets are continuously fed in the first mode, the control means controls the feeding means for a third specific time after the detection means detects the trailing edge of the previously fed sheet. The sheet feeding apparatus according to any one of claims 1 to 4, wherein the measurement of the first specific time is started after stopping. The sheet feeding apparatus according to any one of claims 1 to 5, wherein the first mode is a mode for feeding sheets that are vulnerable to load. When continuously feeding a plurality of sheets in a second mode different from the first mode, the control means keeps the fetching means in contact with the sheets stacked on the sheet stacking table. 7. The sheet feeding device according to claim 1, wherein a plurality of sheets are continuously fed. a retrieving means for retrieving the sheet by rotating while in contact with the sheet stacked on the sheet stacking table;
feeding means for feeding the taken-in sheet in the feeding direction;
a first detection means for detecting the sheet being fed;
a second detection means for detecting movement of the sheets stacked on the sheet stacking table;
When a plurality of sheets are continuously fed, even if the first specific time elapses after the first detection means detects the trailing edge of the previously fed sheet, the second detection means detects the next sheet. When the movement of the sheet is not detected, the fetching means is brought into contact with the sheet stacked on the sheet stacking table, and after the leading end of the sheet is detected by the first detecting means, the fetching means is moved to the sheet. a control means for controlling to move away from
has
The control unit causes the fetching unit to come into contact with the sheets stacked on the sheet stacking table so that the predetermined contact pressure on the sheet changes longer than a preset contact pressure change time. After the second specific time has elapsed, rotating the capturing means in the capturing direction ,
When the detecting means detects the leading edge of the sheet before the second specific time elapses, the fetching means is separated from the sheet without rotating the fetching means in contact with the sheet.
A sheet feeding device characterized by: 9. A sheet feeding apparatus according to claim 8 , wherein said control means controls said take-in means to separate from said sheet when said second detection means detects movement of the next sheet. . The second detection means has an imaging element for imaging a predetermined area of the sheets stacked on the sheet stacking table, and detects the movement of the sheet based on the imaging result of the sheet by the imaging element. 10. The sheet feeding device according to claim 8 or 9 . 11. The sheet according to claim 10 , wherein the imaging device is arranged such that the imaging surface of the imaging device and the surface of the sheets stacked on the sheet stacking table are substantially parallel. feeding device. The imaging device is arranged at a position where the distance between the imaging device and the feeding means in the feeding direction is shorter than the length of the smallest sheet that can be fed by the sheet feeding device in the feeding direction. 12. The sheet feeding device according to claim 10 or 11 , wherein the sheet feeding device is The imaging element has a light source and a light receiving section for receiving reflected light from the sheet surface of the light emitted by the light source, and detects movement of the sheet based on an image captured by the light received by the light receiving section. The sheet feeding device according to any one of claims 10 to 12 , characterized by: A take-in means for taking in a sheet by rotating while being in contact with the sheet stacked on the sheet stacking table, a feeding means for feeding the taken-in sheet in the feeding direction, and a feed means for feeding the sheet. A control method for a sheet feeding device, comprising:
In a predetermined first mode, when a plurality of sheets are continuously fed, the next sheet is not fed even if the first specific time elapses after the detecting means detects the trailing edge of the previously fed sheet. a step of bringing the fetching means into contact with the sheet stacked on the sheet stacking table when the leading edge of the sheet is not detected;
a rotating step of rotating the capturing means in the capturing direction after the elapse of a second specific time;
separating the fetching means from the sheet after the detecting means has detected the leading edge of the sheet;
has
The second specific time is longer than a preset contact pressure change time during which the preset contact pressure on the sheet changes by bringing the fetching means into contact with the sheet stacked on the sheet stacking table. also long ,
In the step of separating the fetching means from the sheet, if the detection means detects the leading edge of the sheet before the second specific time elapses, the fetching means that is in contact with the sheet is rotated. moving the uptake means away from the seat without
A control method for a sheet feeding device, characterized by: A take-in means for taking in a sheet by rotating while being in contact with the sheet stacked on the sheet stacking table, a feeding means for feeding the taken-in sheet in the feeding direction, and a feed means for feeding the sheet. A control method for a sheet feeding device having first detection means for detecting and second detection means for detecting movement of sheets stacked on a sheet stacking table, comprising:
When a plurality of sheets are continuously fed, even if the first specific time elapses after the first detection means detects the trailing edge of the previously fed sheet, the second detection means detects the next sheet. a step of bringing the fetching means into contact with the sheets stacked on the sheet stacking table when the movement of the sheet is not detected;
a step of separating the fetching means from the sheet after the first detecting means has detected the leading edge of the sheet;
has
By bringing the fetching means into contact with the sheets stacked on the sheet stacking table, a preset contact pressure on the sheets changes for a second specific time longer than a preset contact pressure change time. After the passage of time, rotate the fetching means in the fetching direction ,
In the step of separating the fetching means from the sheet, if the detection means detects the leading edge of the sheet before the second specific time elapses, the fetching means that is in contact with the sheet is rotated. moving the uptake means away from the seat without
A control method for a sheet feeding device, characterized by: A program for causing a computer to function as the control means according to any one of claims 1 to 13 .

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