JP7143143B2 - 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.

In a conventional sheet feeding device, when feeding a plurality of sheets continuously, a pickup roller (for example, 4 in FIG. 1, which will be described later) is moved to a sheet loading position each time a sheet is fed. The operation of contacting the sheet, rotating it, and then moving it 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 (eg, 6 and 7 in FIG. 1) and the pickup roller.

Japanese Patent Laid-Open No. 2002-100003 proposes a countermeasure against jamming of sheets such as thin paper.
In Patent Document 1, after a pre-registration sensor (for example, 32 in FIG. 1 to be described later) detects the trailing edge of the previously fed sheet, the pre-registration sensor detects the leading edge of the next sheet even after a specific time has passed. is not detected, the pickup roller is brought into contact with the sheet and rotated. Accordingly, techniques have been proposed for feeding sheets while minimizing the use of the pickup roller.

JP-A-6-9110

The technique disclosed in Japanese Patent Application Laid-Open No. 2002-200301 has a certain effect in countermeasures against jamming of sheets having low stiffness (hereinafter referred to as "elasticity" or "stiffness") such as thin paper. On the other hand, there have been cases where the sheet is caught in the feed rollers that form the pair of separation rollers, resulting in a jam.
As described above, in the conventional technology, there is a problem that a jam may occur in the paper feed roller when the sheet to be fed is thin paper or the like with low stiffness.

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 that is weak in stiffness.

In view of the above, the present invention forms a nip between a feeding roller that feeds a sheet along a conveying path and the feeding roller, and controls the sheet fed by the feeding roller and other sheets. a first sheet detection sensor arranged downstream of the feeding roller in the feeding path to detect arrival of a sheet; and a first conveying roller positioned downstream of the conveying path and further upstream of the conveying path than the first sheet detection sensor for conveying the sheet; and downstream of the first sheet detection sensor in the conveying path to convey the sheet; and a third sheet detecting sensor located upstream of the second conveying roller in the conveying path and detecting arrival of the sheet, and a control section controlling rotation of the feeding roller. wherein the controller controls the feed roller when the feed roller starts feeding the succeeding sheet after the arrival of the trailing edge of the preceding sheet is detected by the first sheet detection sensor. When it is determined that the leading edge of the succeeding sheet has passed the nip between the feeding roller and the separating roller, the feeding roller is set to a speed higher than the first feeding speed. is controlled to the second feeding speed, and the rotation of the feeding roller is stopped when the arrival of the leading edge of the sheet is detected by the third sheet detecting sensor .

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; 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; FIG. 4 is a schematic diagram showing an example of the positional relationship between the leading edge of the document to be fed and the pair of feeding rollers according to the first embodiment; 6 is a flowchart for explaining the control operation of the feed roller in the thin paper mode of the first embodiment; FIG. 5 is a diagram for explaining the relationship among the sheet on the sheet stacking table, the feeding roller, the position of the leading edge of the document, and the feeding speed of the pickup roller according to the first embodiment; FIG. 8 is a diagram for explaining the positional relationship between a feed roller and an optical sensor for thin paper mode according to another aspect of the first embodiment; 8 is a flowchart for explaining the control operation of the feed roller in the thin paper mode according to another aspect of the first embodiment; FIG. 11 is a partial cross-sectional view schematically showing a part of the structure of a sheet conveying device to which the sheet feeding device according to the second embodiment can be applied; 8 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 second embodiment. FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second embodiment; FIG. 11 is a schematic diagram 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 second 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;

[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.
Here, as an example, a case where the sheet conveying apparatus of the present invention is applied to an image reading apparatus will be described. The present invention can be applied to various sheet conveying apparatuses such as an apparatus having a document conveying system such as.

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. The document flip-up detection sensor 35 includes a plurality of sensors arranged in a direction orthogonal to the sheet stacking surface 1a, and detects the flip-up of the sheet stacked on the sheet stacking table 1. FIG. For example, the document flip-up detection sensor 35 can detect document flip-up that occurs when stapled documents are stacked on the sheet stacking table 1 and fed. As a result, it is possible to perform control such as stopping the feeding of stapled documents.

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. In the example of FIG. 1, the pickup roller 4 rotates around a rotation center 64 of the pickup roller provided downstream of the pickup roller 4 in the transport direction. Therefore, when the pickup roller 4 comes into contact with the sheet, the sheet is easily pushed out in the conveying direction.

A control unit 45 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 45 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, the separation and feeding by the separation roller pair 42 can be reliably performed.

In the separation roller pair 42, the feeding roller 6 is driven by the feeding motor 8 so as to rotate in the direction (feeding direction) for feeding the sheet to the downstream side 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 feeding roller 6 and the separation roller 7, the separation roller 7, which is transmitted by the above-mentioned torque limiter, pushes back the sheet upstream from 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. , the uppermost sheet is fed to the downstream side, and the other sheets You will not be transported. 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 section). 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 the plurality of sheets may be prevented from being conveyed to the downstream side by coming into contact with the sheet. 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 pickup unit including the pickup roller 4, the feeding roller 6, the separation roller 7, and the like configured as described above. It is captured.

Further, by providing the multi-feed detection sensor 30 at the position where the separated sheets pass (that is, the downstream side of the separation roller pair 42), it is possible to detect whether the sheets are separated one by one by the sheet separating section. can. 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 amount of ultrasonic attenuation between the transmission/reception units across the transport path. . Note that the double-feeding detection sensor 30 can also be used as a sensor for detecting a sheet that has reached a predetermined position on the conveying path (a position corresponding to an ultrasonic transmission/reception section).

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 discharge 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 (nip pressure) 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 first pair of registration rollers 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 pair of registration rollers, thereby correcting the skew of the sheet.

A second pair of registration rollers consisting of registration rollers 20 and 21, a pair of conveying rollers consisting of conveying rollers 22 and 23, a pair of conveying rollers consisting of conveying rollers 24 and 25, and discharge rollers 26 and 27. The pair of discharge rollers conveys the sheet to the discharge stacking section 44 . A paper discharge sensor 16 detects passage of the conveyed sheet. After the paper discharge sensor 16 detects the trailing edge of the sheet, the paper discharge brake is applied to slow down the rotational speed of the paper discharge roller pair (26, 27) to prevent the discharged sheet from popping out. 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 (fourth sheet detection sensor) is arranged upstream of the registration roller pair (17, 18) and detects the sheet being fed. The post-registration sensor 34 (first sheet detection sensor) is arranged downstream of the registration roller pair (20, 21) and detects the sheet being conveyed. Further, the registering sensor 33 (third sheet detection sensor) is arranged downstream of the pair of registration rollers (17, 18) and upstream of the pair of registration rollers (20, 21) to detect the conveyed sheet. do.

When the sheet is detected by the post-registration sensor 34, the controller 45 issues an image reading instruction to the image reading sensors 14 and 15, and the image of the conveyed sheet is read. 14a and 15a are platen rollers. 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 during execution of the thin paper mode (predetermined specific mode) performed by the control unit 45 of the first embodiment will be described below with reference to FIG.
FIG. 3 is a flow chart for explaining an example of control operation in the thin paper mode (also referred to as "thin paper transport mode") performed by the controller 45 of the first embodiment. That is, the processing shown in this flow chart is realized by the CPU (not shown) of the control unit 45 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 45 drives the feeding roller 6 and starts measuring time (measurement time (TIME)=0) (S101).
Next, in S102, the control unit 45 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 S102), the control unit 45 advances the process to S103.
In S103, the control unit 45 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 45 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 45 advances the process to S104

In S104, the control unit 45 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 45 rotates the pickup roller 4 after a specific time (TD), which will be described later, has elapsed. As a result, the pickup roller 4 feeds the sheet to the feeding roller 6 .

Next, in S106, the control unit 45 starts measuring time again (measurement time (TIME)=0).
Then, in S107, the control unit 45 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 45 advances the process to S110.
In S110, the control unit 45 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 45 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 45 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. is doing.
The control unit 45 moves the pickup roller 4 to the retracted position (S111), stops the rotation of the pickup roller 4 (S112), and terminates 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 45 advances the process to S108.
The control unit 45 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 45 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 . In this situation, after the sheet reaches the feed roller 6 due to friction and static electricity generated between the previously fed sheet and the feed roller 6, the previously fed sheet leaves the feed roller 6. 6 and reaches at least the pre-registration sensor 32 . 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 45 advances the process to S113. In S113, the control unit 45 issues an image reading instruction to the image reading sensors 14 and 15 at a predetermined timing after the post-registration sensor 34 detects the leading edge of the sheet, and the image reading sensors 14 and 15 read the sheet. read operation. During this time, the control unit 45 monitors detection of the trailing edge of the sheet by the pre-registration sensor 32 (S114). If it is determined that the pre-registration sensor 32 has not detected the sheet trailing edge (No in S114), the control unit 45 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 45 advances the process to S115. Note that the control unit 45 terminates the reading operation of S113 at a predetermined timing after the post-registration sensor 34 detects the trailing edge of the sheet.

At S115, the control unit 45 checks whether or not there is a sheet on the sheet stacking table 1. FIG. If it is determined that there is a sheet on the sheet stacking table 1 (Yes in S115), that is, if there is a next sheet, the control section 45 returns the process to S101.
On the other hand, if it is determined that there is no sheet on the sheet stacking tray 1 (No in S115), that is, if there is no next sheet, the control section 45 terminates the processing of this flowchart. Before ending, it is preferable to wait for a specific time (TS) or longer, and if the sheet is detected by the pre-registration sensor 32, proceed to S113, and if the sheet is not detected, end the process. .

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. Note that in FIG. 4B, the output of the pre-registration sensor 32 is turned off before counting the measurement time (TIME). This indicates that the pre-registration sensor 32 itself is not driven and the output is OFF before the start of counting the measurement time (TIME). 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. The pre-registration sensor 32 is arranged on the other side (upper guide plate 40, for example) of the transport path, facing the irradiation light from the light source arranged on one side (lower guide plate 41, for example) of the transport path. The sheet is detected by receiving the light returned to one side again by the optical member with the light receiving section. Therefore, when there is a sheet at the sensor position, the irradiation light is blocked, so the light reception level at the light receiving section becomes L level. In this embodiment, the output is turned ON when the received light level is L level. On the other hand, when there is no sheet at the sensor position, the irradiated light is returned without being blocked, so the light receiving level at the light receiving section becomes H level. In this embodiment, the output is turned off when the received light level is H level. This is the same for other sensors in this embodiment.

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. However, the specific time period (TS) is not limited to 1 second.

FIG. 5 is a graph illustrating changes in contact pressure with respect to the sheet after the pickup roller 4 is brought into contact with the sheet.
As shown in FIG. 5, 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 rotation of the pickup roller 4 is started before the time TC elapses, the sheets are likely to be brought in, and the paper feed jam is likely to occur.
On the other hand, in the present embodiment, the specific time (TD) from when the pickup roller comes into contact with the sheet to when it rotates is set longer than the contact pressure change time (TC) shown in FIG. It has started and its time is set to say 0.2 seconds. However, the specific time (TD) is not limited to 0.2 seconds.

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 leading edge of the next sheet is not detected even after the waiting time (TS) has passed. Then, the pickup roller is moved to the position where it contacts the sheet stacked on the sheet stacking table, and after TD has passed, the pickup roller is rotated, and after the pre-registration sensor detects the leading edge of the sheet, the pickup roller is moved to the sheet. It is characterized by retracting to a position where it does not come into contact with and stopping the 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 movement and rotation of the pickup roller 4 may be controlled using the during-registration sensor 33 instead of the pre-registration sensor 32 . That is, when the registering sensor 33 detects the trailing edge of the previously separated and fed sheet and does not detect the leading edge of the next sheet even after the standby time (TS) has passed, the pickup roller 4 is moved to the sheet stacking position. After moving to the position where the sheet stacked on the table is brought into contact with the sheet, rotating the pickup roller 4 after TD has passed, and after the sensor 33 during registration detects the leading edge of the sheet, the pickup roller 4 is not brought into contact with the sheet. You may make it retract to a position and stop rotation.

Note that the sheet conveying apparatus 200 of the present embodiment has a plain paper mode (also referred to as a "normal conveying mode") different from the thin paper mode described above, and these modes can be combined with an operation panel (not shown) or the sheet conveying apparatus 200. It can be selected and set from the connected information processing device (for example, personal computer). In a state in which the plain paper mode different from the thin paper mode is set, the control unit 45 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.

<Countermeasures against getting caught in the feed roller>
Here, when the sheet feeding apparatus 101 described in the present embodiment starts conveying thin paper, the sheet is caught in the feeding roller 6, causing a sheet jam in the feeding roller 6. There was something I ended up doing. Especially when the thin paper mode is applied, thin paper with weak stiffness is likely to be caught in the feed roller 6, and effective control for preventing this will be described below.

FIG. 6 is a schematic diagram showing an example of the positional relationship between the leading edge of the document to be fed and the pair of feeding rollers according to the first embodiment.
FIG. 6A shows a state in which the leading edge of the document has reached the nip formed between the feeding roller 6 and the separating roller 7. FIG.
FIG. 6B shows a state in which the leading edge of the document has passed through the nip portion formed between the feeding roller 6 and the separation roller 7. FIG.

FIG. 7 is a flow chart for explaining an example of the feeding control operation in the thin paper mode performed by the controller 45 of the first embodiment. This control is to prevent the leading edge of the sheet from being caught in the feeding roller 6 when thin paper with low stiffness reaches the feeding roller 6 . Further, the processing shown in this flowchart is realized by the CPU (not shown) of the control unit 45 executing a program stored in the ROM. The control shown in FIG. 7 and the control shown in FIG. 3 are performed together in one feeding operation.

The control unit 45 drives the conveying roller when the feeding operation in the thin paper mode is started. After that, the conveying roller is controlled so as to continue to be driven.
Next, the control unit 45 starts measuring time (measurement time (TIME)=0) (S201).
Further, the control unit 45 drives the feeding roller 6 at the first feeding speed V3 (low speed) at which the sheet is not caught in the feeding roller 6 (S202). The control unit 45 controls the time interval from when the leading edge of the sheet is fed from the sheet stacking table 1 to when it passes through the nip formed between the feeding roller 6 and the separation roller 7 (TIME<T3). , continue to drive the feeding roller 6 at the first feeding speed V3.

Then, the control unit 45 waits for the predetermined time T3 to elapse (S203).
When determining that the predetermined time T3 has passed (Yes in S203), the control unit 45 determines that the leading edge of the sheet has passed through the nip portion formed between the feeding roller 6 and the separating roller 7. , the feeding roller 6 is switched to the second feeding speed V4 (high speed) and driven (S204). The second feeding speed V4 (high speed) is higher than the first feeding speed V3 (low speed), and is equal to or close to the feeding speed for driving the registration rollers 17, 18, 20, and 21, for example. It is about the same speed.

After that, the control unit 45 monitors whether or not it is detected that the leading edge of the sheet has reached the in-registration sensor 33 (S205). If it is determined that the leading edge of the sheet has not reached the in-registration sensor 33 (No in S205), the control unit 45 continues monitoring in S205. If it is determined that the leading edge of the sheet has reached the in-registration sensor 33 (Yes in S205), the control unit 45 proceeds to S206 and subsequent steps.
The control unit 45 stops driving the feeding motor 8 (S206), resets the count TIME for driving control of the feeding roller 6 to "0", and stops measuring time (S207).

Next, the control unit 45 monitors whether or not it has detected that the leading edge of the sheet has reached the post-registration sensor 34 (S208). If the post-registration sensor 34 has not detected that the leading edge of the sheet has arrived (No in S208), the monitoring of S208 is continued.
Then, when it is detected that the leading edge of the sheet has reached the post-registration sensor 34 (Yes in S208), the control unit 45 starts the image reading operation by the image reading sensors 14 and 15 at a predetermined timing (S209). .

Thereafter, the control unit 45 monitors whether the trailing edge of the sheet has reached the post-registration sensor 34 (S210). If the post-registration sensor 34 has not detected the arrival of the trailing edge of the sheet (No in S210), the control unit 45 continues the image reading operation in S209.

Then, when the post-registration sensor 34 detects the arrival of the sheet trailing edge (Yes in S210), the control unit 45 advances the process to S211.
In S211, the control unit 45 checks whether or not there is a sheet on the sheet stacking table 1. FIG. If it is determined that there is a sheet on the sheet stacking table 1 (Yes in S211), that is, if there is a next sheet, the control section 45 returns the process to S201.
On the other hand, if it is determined that there is no sheet on the sheet stacking tray 1 (No in S211), that is, if there is no next sheet, the control section 45 ends the processing of this flowchart.

As described above, when the driving of the feed roller 6 is restarted after the post-registration sensor 34 detects the arrival of the trailing edge of the sheet, the feed roller 6 is controlled to the first feeding speed. Further, when it is determined that the leading edge of the sheet succeeding the sheet has passed the nip between the feeding roller 6 and the separating roller 7, the feeding roller 6 is set to the second feeding speed higher than the first feeding speed. Control. With such control, even if the sheet to be fed is a thin sheet with low stiffness, it is possible to prevent the occurrence of a jam such as the sheet being caught in the feeding roller during feeding.

In S210, instead of detecting the arrival of the trailing edge of the sheet by the post-registration sensor 34, if the arrival of the trailing edge of the sheet is detected by the mid-registration sensor 33 or the pre-registration sensor 32, the process proceeds to S211. can be In these cases, the sheet interval can be narrowed compared to the case where the post-registration sensor 34 detects the arrival of the trailing edge of the sheet.
Further, in the present embodiment, the configuration in which the during-registration sensor 33 and the post-registration sensor 34 are provided and used to perform the above-described control has been described, but the above-described control may be performed by one sensor. For example, the in-registration sensor 33 may be omitted, and the post-registration sensor 34 may be used to perform the above control. In this case, in S205, if the post-registration sensor 34 detects the leading edge of the sheet, the process proceeds to S206, and the process of S208 is omitted.

A method of determining the time (T3) for driving the feeding motor 8 so that the feeding roller 6 reaches the first feeding speed V3 (low speed) will be described below with reference to FIG.
FIG. 8 is a diagram for explaining the relationship between the sheet (original) on the sheet stacking table 1, the feeding roller 6, the position of the leading end of the original, and the feeding speed of the pickup roller 4. As shown in FIG.

When the document is fed by the pickup roller 4 at a feeding speed of V5, the leading edge of the document (length X from the leading edge of the document) is the nip portion formed between the feeding roller 6 and the separation roller 7. The maximum time of the predetermined time T3 corresponding to the time required to pass through is calculated as follows. Assuming that the distance from the leading edge of the document stacked on the sheet stacking table 1 to the feeding roller 6 is D as shown in FIG. 8, the predetermined time T3 can be calculated by "T3=(D+X)/V5". The length X of the leading edge of the document may be set to about 1/4 of the circumference of the feeding roller 6, for example. Here, the position of the nip portion between the feed roller 6 and the separation roller 7 is set as the center position of the shaft of the feed roller 6. As shown in FIG.

In the above description, the configuration in which the driving speed of the feeding roller 6 is changed from V3 to V4 at the timing when the post-registration sensor 34 detects that T3 has passed since the trailing edge of the preceding sheet was detected has been described. However, as another example of the elapse of the predetermined time T3, when the driving pulses of the feeding motor 8 for conveying the sheet by the feeding roller 6 are counted by "D+X" shown in FIG. The driving speed of the feeding roller 6 may be changed from V3 to V4 assuming that the time has elapsed.

Note that the first feeding speed V3 (low speed) is such that even if the feeding motor 8 that drives the feeding roller 6 starts up and overshoots, the peripheral speed of the feeding roller 6 is kept at the second feeding speed. Set the speed to about V4 (high speed). It should be noted that this set speed is obtained in advance through experiments or the like.
Also, the first feeding speed V3 and the feeding speed V5 by the pickup roller 4 may be set to be equal.
When the plain paper mode is set, the control unit 45 controls the feeding roller 6 at the second feeding speed V4 (high speed) when the driving of the feeding roller 6 is started.

A plurality of stacked documents are fed at the same time due to friction between the documents, and by passing the pickup roller 4, the next document to be fed is already in the nip between the feed roller 6 and the separation roller 7. In some cases, it may be in a so-called entrained state where it exists in a position close to the part. In this case, as described above, if the speed is changed at the predetermined time T3, the leading edge of the document will pass through the nip portion between the feeding roller 6 and the separation roller 7 immediately. That is, in this case, even when the leading edge of the document passes through the nip portion and it is possible to switch to the speed V4, the document is continuously fed at the speed V3 until the predetermined time T3 elapses, resulting in a decrease in throughput. may be lost.

Other aspects of the present embodiment in consideration of this point will be described below.
FIG. 9 is a diagram illustrating a configuration in which a thin paper transport registration sensor 65 (second sheet detection sensor), which is an optical sensor for the thin paper mode, is arranged in a position parallel to the feed roller 6 in the document transport direction. be.
FIG. 9(a) shows a state in which the leading edge of the document has reached the nip portion formed between the feeding roller 6 and the separation roller 7. FIG.
FIG. 9(b) shows a state in which the leading edge of the document has passed through the nip formed between the feed roller 6 and the separation roller 7 and reached the registration sensor 65 for conveying thin paper.

FIG. 10 shows the feeding control operation in this mode.
FIG. 10 is a flow chart illustrating an example of the feeding control operation in the thin paper mode performed by the control section 45 in another aspect of the first embodiment. The processing shown in this flowchart is realized by the CPU (not shown) of the control unit 45 executing a program stored in the ROM. The same step numbers are given to the same steps as in FIG. The control shown in FIG. 10 and the control shown in FIG. 3 are performed together in one feeding operation.

In this aspect, the timing at which the document passes the feeding roller 6 can be accurately detected by the thin paper transport registration sensor 65 . In FIG. 10, the control unit 45 drives the feeding roller 6 at the first feeding speed V3 (low speed) (S202), and then proceeds to S212.
In S212, the control unit 45 monitors whether or not the thin paper transport registration sensor 65 has detected the leading edge of the document. If it is determined that the thin paper transport registration sensor 65 has not yet detected the leading edge of the document (No in S212), the control unit 45 continues monitoring in S212.

On the other hand, if it is determined that thin paper transport registration sensor 65 has detected the leading edge of the document (Yes in S212), control unit 45 advances the process to S204. The processing after S204 is the same as that in FIG. 7, so the description is omitted.
In this way, when the thin paper transport registration sensor 65 detects the leading edge of the document, the controller 45 changes the driving speed of the feeding roller 6 from the first feeding speed V3 to the second feeding speed V4. . With this configuration, it is possible to more effectively control the speed for conveying thin paper. Preferably, the optical sensor detects that the leading edge of the document has passed through the nip formed by the feeding roller 6 and the separating roller 7, so that the detection position of the optical sensor is between the feeding roller 6 and the separating roller 7. It is preferably downstream of the position of the nip formed by 7.

Further, the registration sensor 65 for transporting thin paper may be a detection sensor other than an optical sensor. effect can be obtained.

In S212, the drive speed of the feeding roller 6 is changed from V3 to V4 in accordance with the detection of the leading edge of the document by the pre-registration sensor 32 instead of the detection of the leading edge of the document by the thin paper transport registration sensor 65. may
Further, instead of detecting the leading edge of the document by the thin paper transport registration sensor 65, the driving speed of the feeding roller 6 may be changed from V3 to V4 according to the detection of the document by the double feeding detection sensor 30. FIG.
In the case of an apparatus having a skew sensor (for example, composed of a plurality of optical sensors arranged in two rows in the document transport direction) on both sides of the transport path downstream of the separation roller pair 42, the skew sensor detects the document. The feeding speed may be switched when the number is changed.
That is, the feeding speed may be switched when the document is detected by any of the sensors provided downstream of the separation roller pair 42, and the type of the sensor may be of any detection method.

Furthermore, the aspects shown in FIGS. 6 to 8 may be combined with the other aspects shown in FIGS. 9 and 10. FIG. For example, the control unit 45 controls the feeding operation at the timing T3 after the trailing edge of the preceding sheet is detected by the post-registration sensor 34 or the timing at which the registration sensor 65 for conveying thin paper detects the succeeding sheet, whichever is earlier. The driving speed of the feed roller 6 may be changed from V3 to V4.

[Second embodiment]
Next, a second embodiment of the invention will be described. In the second embodiment, an 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, 18) may be turned ON/OFF at the timing of turning ON/OFF the driving of the feeding roller 6 (separation roller 7). 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. 11 is a partial cross-sectional view schematically showing a part of the configuration of a sheet conveying device (image reading device) to which the sheet feeding device according to the second 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. 11, the registration roller pair (20, 21) is arranged downstream of the registration roller pair (17, 18). The during-registration sensor 33 (third sheet detection sensor) is arranged downstream of the pair of registration rollers (17, 18) and upstream of the pair of registration rollers (20, 21) to detect the sheet being conveyed. . The post-registration sensor 34 is arranged downstream of the pair of registration rollers (20, 21) and upstream of the image reading sensors 14, 15, and detects the conveyed sheet.

FIG. 12 is a timing chart showing an example of the relationship between the operations of the pickup roller and the feeding roller (and the registration roller pair) and the detection states of the pre-registration sensor and the during-registration sensor in the second embodiment.
13 to 16 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 second 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, 20, 21) are driven (Fig. 13 (0)), the pickup roller 4 is moved to the contact position (Fig. 13 (1)), and a specific time ( TD), it rotates ((2) in FIG. 13) and feeds the sheet to the feeding roller 6 . When the leading edge of the sheet reaches the pre-registration sensor 32 ((3) in FIG. 13), the pickup roller 4 is moved to the retracted position ((4) in FIG. 14) and stops rotating ((4)' in FIG. 14). Then, when the leading edge of the sheet reaches the in-registration sensor 33 ((5) in FIG. 14), the feeding roller 6 is stopped ((6) in FIG. 14). Then, the trailing edge of the sheet passes the pre-registration sensor 32 ((7) in FIG. 15) (this time is defined as "t0"), and after t1 ((8) in FIG. 15), the feeding roller 6 is rotated. Thereafter, the trailing edge of the sheet passes through the in-registration sensor 33 ((8)' in FIG. 15). Also, after t2 (preferably t2>t1+L/V1) has elapsed from time t0 (preferably t2>t1+L/V1) ((9) in FIG. 15), the pickup roller 4 is moved to the contact position ((10) in FIG. 15), and a specific time (TD) After the passage of time, it rotates ((11) in FIG. 16), and feeds the next sheet to the feeding roller 6 . As shown in FIG. 20, 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 L, t2 is preferably "t2>t1 +L/V1”.

If the leading edge of the next sheet is detected by the pre-registration sensor 32 during the period from t1 to t2 ((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 33 as shown in FIG. 14(5). This example will be described in detail below with reference to FIGS. 17 to 19. FIG.
17 to 19 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 second 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.

17 to 19, the feed roller 6 and registration rollers (17, 18, 20, 21) are first driven (Fig. 17 (0 )), the pickup roller 4 is moved to the contact position ((1) in FIG. 17), rotated after a specific time (TD) has elapsed ((2) in FIG. 17), 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 ((3) in FIG. 17), the pickup roller 4 is moved to the retracted position ((4) in FIG. 18) and stops rotating ((4)' in FIG. 18). . In this example, as shown in FIG. 18, 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 33 ((5) in FIG. 18), the feeding roller 6 is stopped ((6) in FIG. 18). Further, the trailing edge of the first sheet passes the pre-registration sensor 32 ((7) in FIG. 19) (this time is defined as "t0"), and after t1 ((8) in FIG. 19), 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 33 ((8)' in FIG. 19). 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 ((8)'' in FIG. 19). 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 33 ((5) in FIG. 18). do.

As described above, as shown in FIGS. 12, 13 to 16, and 17 to 19, a predetermined time (t1) has elapsed after the trailing edge of the sheet passed the pre-registration sensor 32 after the sheet passed the mid-registration sensor 33. 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 33 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. 20 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 32. exists at a position advanced from the position of the feeding roller 6 by "V1×(L/V2)". Therefore, after waiting 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 32 at the feeding speed V1, the second sheet should reach the pre-registration sensor 32 . 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.

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. is not. In other words, the present invention includes all configurations obtained by combining each of the above-described embodiments and modifications thereof.

In addition, in the present invention, the feeding motor 8 is controlled to stop when the leading edge of the sheet reaches the in-registration sensor 33, for example, as shown in S206 of FIG. do not have. The feeding roller 6 can be configured to rotate together with the document by the action of a one-way clutch or the like attached inside it. The paper feed rollers may become a resistance and easily damage the document. In this case, when the leading edge of the sheet reaches the registering sensor 33, the feed roller 6 is controlled to the same speed as the registration rollers 20 and 21 (higher than V4) to feed the long document. The load from roller 6 can be reduced. In this case, the feed motor may be stopped so that the rotation of the feed roller 6 is stopped when the trailing edge of the sheet is detected by the pre-registration sensor 32 or the registration sensor 65 for conveying thin paper.

In the sheet feeding apparatus 101 shown in FIGS. 1 and 2, the pickup roller disposed above the sheet stacking table comes into contact with the sheets stacked on the vertically movable sheet stacking table from above, thereby The configuration has been described in which sheets are supplied to the feeding roller in order from the upper side of the . However, for example, a pick-up roller arranged below the sheet stacking table comes into contact with the sheets stacked on the inclined sheet stacking table from below, and the sheets are fed to the feeding roller in order from the bottom of the sheet bundle. The present invention can also be applied to a sheet feeding apparatus configured to supply sheets.

1 sheet stacker
4 Pickup roller
6 Feed roller
7 Separation roller
17, 18, 20, 21 Registration roller (conveyance roller)
32 Pre-registration sensor (4th sheet detection sensor)
33 In-registration sensor (3rd sheet detection sensor)
34 Post-registration sensor (1st sheet detection sensor)
65 Thin paper transfer registration sensor (second sheet detection sensor)

Claims (11)

a feeding roller that feeds the sheet along the conveying path;
a separation roller for forming a nip with the feeding roller and separating the sheet fed by the feeding roller from other sheets;
a first sheet detection sensor arranged downstream of the feeding roller in the conveying path and detecting arrival of a sheet;
a first conveying roller positioned downstream of the feeding roller in the conveying path and upstream of the first sheet detection sensor in the conveying path for conveying the sheet;
a second conveying roller positioned downstream of the first conveying roller in the conveying path and upstream of the first sheet detecting sensor in the conveying path to convey the sheet;
a third sheet detection sensor located downstream of the first conveying roller in the conveying path and upstream of the second conveying roller in the conveying path and detecting arrival of the sheet; a control unit that controls the rotation of the feeding roller,
When the first sheet detection sensor detects the arrival of the trailing edge of the preceding sheet, the control unit moves the feeding roller to the first sheet when the feeding roller starts feeding the succeeding sheet. to control the feeding speed ,
controlling the feeding roller to a second feeding speed higher than the first feeding speed when it is determined that the leading edge of the succeeding sheet has passed the nip between the feeding roller and the separation roller; ,
A sheet feeding apparatus , wherein the rotation of the feeding roller is stopped when the arrival of the leading edge of the sheet is detected by the third sheet detection sensor . The control unit determines that the leading edge of the succeeding sheet has passed the nip when a predetermined time has elapsed since arrival of the trailing edge of the preceding sheet was detected by the first sheet detection sensor. The sheet feeding device according to claim 1, characterized by: a feeding roller that feeds the sheet along the conveying path;
a separation roller for forming a nip with the feeding roller and separating the sheet fed by the feeding roller from other sheets;
a first sheet detection sensor arranged downstream of the feeding roller in the conveying path and detecting arrival of a sheet;
a first conveying roller positioned downstream of the feeding roller in the conveying path and upstream of the first sheet detection sensor in the conveying path for conveying the sheet;
a second conveying roller positioned downstream of the first conveying roller in the conveying path and upstream of the first sheet detecting sensor in the conveying path to convey the sheet;
a third sheet detection sensor located downstream of the first conveying roller in the conveying path and upstream of the second conveying roller in the conveying path for detecting arrival of the sheet;
a control unit that controls the rotation of the feeding roller,
When the first sheet detection sensor detects the arrival of the trailing edge of the preceding sheet, the control unit moves the feeding roller to the first sheet when the feeding roller starts feeding the succeeding sheet. to control the feeding speed ,
When the time corresponding to the time from when the subsequent sheet stacked on the sheet stacking table is fed until the leading edge of the sheet passes the nip, the feeding roller is set to the first feeding. Control to a second feeding speed higher than the speed,
A sheet feeding apparatus , wherein the rotation of the feeding roller is stopped when the arrival of the leading edge of the sheet is detected by the third sheet detection sensor . a second sheet detection sensor positioned downstream of the nip in the conveying path and upstream of the first conveying roller in the conveying path for detecting arrival of the sheet;
4. The control unit according to claim 1, wherein the controller controls the feeding roller to the second feeding speed when the arrival of the leading edge of the sheet is detected by the second sheet detection sensor. The sheet feeding device according to the paragraph. 5. The sheet feeding apparatus according to any one of claims 1 to 4 , further comprising a pickup roller arranged above the sheets stacked on the sheet stacking table to supply the sheet to the feeding roller. . a fourth sheet detection sensor located downstream of the feeding roller in the conveying path and upstream of the first conveying roller in the conveying path to detect arrival of the sheet; have
After detecting the arrival of the trailing edge of the preceding sheet by the first sheet detection sensor and restarting the driving of the feeding roller, the controller detects the fourth sheet even if a preset waiting time elapses. When the arrival of the leading edge of the subsequent sheet is not detected by the sheet detection sensor, the sheet is supplied by the pickup roller, and the leading edge of the subsequent sheet is detected by the fourth sheet detection sensor before the waiting time elapses. 6. The sheet feeding apparatus according to claim 5 , wherein when the arrival of the pickup roller is detected, control is performed so that the sheet is not fed by the pickup roller. It has a thin paper transport mode and a normal transport mode ,
a feeding roller that feeds the sheet along the conveying path;
a separation roller for forming a nip with the feeding roller and separating the sheet fed by the feeding roller from other sheets;
a control unit that controls the rotation of the feeding roller,
When the thin paper transport mode is executed , the control unit moves the feed roller to the first position until the leading edge of the sheet passes over the nip between the feed roller and the separation roller. After the leading edge of the sheet has passed the nip, the feeding roller is controlled to a second feeding speed higher than the first feeding speed,
A sheet feeding apparatus , wherein when the normal feeding mode is executed, the sheet feeding apparatus is controlled at the second feeding speed when the feeding roller is started to be driven . A separation for forming a nip between a feeding roller that feeds a sheet along a conveying path and the feeding roller to separate the sheet fed by the feeding roller from other sheets a roller, a first sheet detection sensor disposed downstream of the feed roller in the transport path and detecting arrival of a sheet, and a downstream side of the transport path of the feed roller. and a first conveying roller positioned upstream of the first sheet detection sensor in the conveying path to convey the sheet, and downstream of the first conveying roller in the conveying path, and a second conveying roller positioned upstream of the first sheet detection sensor in the conveying path to convey the sheet; Control of a sheet feeding device provided with a third sheet detection sensor located upstream of a roller in the conveying path and detecting arrival of the sheet, and a control section controlling rotation of the feeding roller a method,
When the controller starts feeding the succeeding sheet by the feeding roller after the arrival of the trailing edge of the preceding sheet is detected by the first sheet detection sensor, the feeding roller is moved to the first position. controlling the feeding speed;
When the controller determines that the leading edge of the succeeding sheet has passed the nip between the feeding roller and the separation roller, the feeding roller is set to a second feeding speed higher than the first feeding speed. a speed controlling step;
a step in which the control unit stops rotation of the feeding roller when the arrival of the leading edge of the sheet is detected by the third sheet detection sensor ;
A control method for a sheet feeding device, comprising: A separation for forming a nip between a feeding roller that feeds a sheet along a conveying path and the feeding roller to separate the sheet fed by the feeding roller from other sheets a roller, a first sheet detection sensor disposed downstream of the feed roller in the transport path and detecting arrival of a sheet, and a downstream side of the transport path of the feed roller. and a first conveying roller positioned upstream of the first sheet detection sensor in the conveying path to convey the sheet, and downstream of the first conveying roller in the conveying path, and a second conveying roller positioned upstream of the first sheet detection sensor in the conveying path to convey the sheet; Control of a sheet feeding device provided with a third sheet detection sensor located upstream of a roller in the conveying path and detecting arrival of the sheet, and a control section controlling rotation of the feeding roller a method,
When the controller starts feeding the succeeding sheet by the feeding roller after the arrival of the trailing edge of the preceding sheet is detected by the first sheet detection sensor, the feeding roller is moved to the first position. controlling the feeding speed;
When the time corresponding to the time from when the subsequent sheet stacked on the sheet stacking table is fed to when the leading edge of the sheet passes over the nip, the control unit moves the feeding roller to the above-described second position. a step of controlling to a second feeding speed higher than the first feeding speed;
a step in which the control unit stops rotation of the feeding roller when the arrival of the leading edge of the sheet is detected by the third sheet detection sensor ;
A control method for a sheet feeding device, comprising: A feed roller that has a thin paper transport mode and a normal transport mode and feeds a sheet along a transport path, and a nip is formed between the feed roller and the sheet fed by the feed roller. A control method for a sheet feeding device comprising: a separation roller for separating a sheet from another sheet; and a control section for controlling rotation of the feeding roller,
a step in which the control unit controls the feed roller to a first feed speed until the leading edge of the sheet passes over the nip between the feed roller and the separation roller when the thin paper transport mode is executed; ,
a step in which the control unit controls the feeding roller to a second feeding speed higher than the first feeding speed after the leading edge of the sheet has passed the nip;
a step in which the control unit performs control at the second feeding speed when the feeding roller starts to be driven when the normal feeding mode is executed;
A control method for a sheet feeding device, comprising: A program for causing a computer to function as the controller according to any one of claims 1 to 7 .

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