KR20210116744A - Structure for compensating driving force of roller under load torque - Google Patents

Abstract

The present invention relates to a structure for compensating a driving force of a roller under load torque, which maintains constant speed property of a sheet transfer device. According to the present invention, a sheet transfer device comprises: first and second transfer rollers; a first driving source generating a first driving force for rotationally driving the first transfer roller; a second driving source generating a second driving force for rotationally driving the second transfer roller; a first power transmission structure configured to transmit the first driving force to the first transfer roller; a second power transmission structure configured to transmit the second driving force to the second transfer roller; and a selective power transmission structure configured to selectively connect the first power transmission structure and the second power transmission structure on the basis of the rotational speed of the first transfer roller and selectively transmit the second driving force to the first transfer roller.

Description

Structure for compensating driving force of roller under load torque

The paper transport device is a device that transports paper, and may be built in an image forming apparatus, a scanner device, or the like.

The paper conveying apparatus may include a pair of conveying rollers disposed to face each other and rotating. As the pair of conveying rollers rotate at a predetermined rotation speed, the paper inserted therebetween is conveyed at the predetermined speed.

However, the state of the paper used in the paper transport device may vary depending on various causes, such as a user's selection or a change in environmental factors. Examples of the change in the state of the paper may include a change in the thickness of the paper, a change in the material of the paper, or a change in the surface friction force of the paper.

As such, when the state of the paper is changed, an unintentional load torque may act on one of the pair of transfer rollers. This load torque may be transmitted to a driving source that rotates the corresponding conveying roller, thereby reducing the rotational speed of the corresponding conveying roller. This can change the paper conveying speed of the paper conveying device. That is, the constant property of the paper conveying device may be deteriorated.

1 is a schematic perspective view of a paper transport device according to an embodiment;
Figure 2 is a schematic plan view of an embodiment of the paper transport device shown in Figure 1,
3 is a view for explaining the operation of the first transfer roller and the second transfer roller.
4 is a view for explaining a state when a load torque is concentrated on some conveying rollers.
5 is an enlarged perspective view of a part of the paper transport device of FIG. 1;
6 is a side view of a part of the paper transport device of FIG. 1 as viewed from the side.
7 is a cross-sectional view taken along line VII-VII of FIG. 5 .
FIG. 8 is a view for explaining the operation of the one-way bearing in the paper transport device of FIG. 5 .
9 is a view for explaining a selective power transmission structure according to another embodiment.
10 is a diagram for explaining a scanner device employing a paper transport device.
11 is a schematic configuration diagram of an image forming apparatus employing a paper transfer apparatus according to an embodiment.
12 is a schematic diagram of an embodiment of a multifunction peripheral.

Hereinafter, embodiments of the post-processing apparatus will be described with reference to the drawings. In the drawings, the same reference numerals refer to the same components, and the size or thickness of each component may be exaggerated for clarity of description.

1 is a schematic perspective view of a paper conveying apparatus 1 according to an embodiment, FIG. 2 is a schematic plan view of an embodiment of the paper conveying apparatus 1 shown in FIG. 1, and FIG. 3 is a first conveying roller ( 11) and a diagram for explaining the operation of the second transfer roller 12 .

The paper conveying device 1 is a device for conveying the paper P, and includes a first conveying roller 11 and a second conveying roller 12 . The paper transport apparatus 1 may further include a pickup member 13 (pickup roller).

The paper conveying device 1 according to an exemplary embodiment will be mainly described as a paper feeding device for feeding the paper P disposed on the loading table 10 . However, the paper transport device 1 is not limited thereto, and as long as it is a device for transporting the paper P in addition to the paper feeding device, it may be applied to various parts or devices.

The pickup member 13 is brought into contact with the paper P positioned at the top among the papers P loaded on the mounting table 10 , for example. The pickup member 13 may have a roller shape, but is not limited thereto, and may have various shapes such as a belt shape.

When the pickup member 13 is rotated, the paper P is taken out from the mounting table 10 . The paper picked up by the pickup member 13 may be conveyed by the first conveying roller 11 and the second conveying roller 12 .

When the pickup member 13 rotates, depending on the case, the paper P and one or more sheets of paper P positioned thereunder may be withdrawn together, which is referred to as multi-feeding.

The paper conveying device 1 may function as a separating device. For example, when medium feeding occurs, the paper conveying device 1 may separate only one sheet of paper, for example, the paper P1 and transfer it along the take-out direction.

The second conveying roller 12 may be a feed roller that conveys the paper P1 in the withdrawal direction A1, and the first conveying roller 11 may be a retard roller that faces and contacts the second conveying roller 12 have. The second conveying roller 12 and the first conveying roller 11 may be rotated while being engaged with each other. The second conveying roller 12 may be configured to rotate in the first direction B1 for conveying the paper P1 in the take-out direction A1. The first conveying roller 11 may be configured to rotate in the second direction B2 for conveying the paper P2 in the reverse direction A2 of the take-out direction A1.

For rotation of the first conveying roller 11 in the second direction, the first conveying roller 11 may be connected to the first driving source 21 . For rotation of the second conveying roller 12 in the first direction, the second conveying roller 12 may be connected to the second driving source 22 .

The first driving force of the first driving source 21 may be transmitted to the first conveying roller 11 by the first power transmitting structure 31 , and the second driving force of the second driving source 22 may be transmitted to the second power transmitting structure. It can be transferred to the second conveying roller 12 by 32 .

The first driving source 21 may be a direct current (DC) motor whose speed varies according to a change in the magnitude of the load torque when a predetermined load torque is applied. For example, when a load torque applied to the first transfer roller 11 is transmitted to the first drive source 21 through the first power transmission structure 31 , the first drive source 21 responds to the magnitude of the load torque. It may be a direct current (DC) motor whose speed varies depending on the The first driving source 21 may be a DC motor capable of rotating even when a predetermined load torque is applied. For example, the first driving source 21 may be a brush DC motor or a brushless DC motor.

A first detection unit 25 for detecting a rotation speed may be installed in the first driving source 21 . The first detection unit 25 may be an encoder. However, the first detection unit 25 is not limited thereto, and may be variously modified for detecting the rotation speed.

The first detection unit 25 detects the rotation speed of the first driving source 21 , and transmits the detected rotation speed to the control unit 27 . The controller 27 may compensate for the speed change of the first drive source 21 by controlling the voltage or current supplied to the first drive source 21 in consideration of the speed change of the first drive source 21 . For example, when the speed of the first drive source 21 decreases as the load torque applied to the first drive source 21 increases, the control unit 27 increases the voltage applied to the first drive source 21, The speed of the first driving source 21 may be increased again.

The second driving source 22 may be a motor whose speed varies according to a change in the load torque when a predetermined load torque is applied to the second power transmission structure 32 . The second driving source 22 may be a DC motor capable of rotation even when a predetermined load torque is applied. For example, the second driving source 22 may be a brush DC motor or a brushless DC motor.

A second detection unit 26 for detecting a rotation speed may be installed in the second driving source 22 . The second detector 26 may be an encoder. However, the second detection unit 26 is not limited thereto, and may be variously modified to detect the rotation speed.

The second detection unit 26 detects the rotation speed of the second driving source 22 , and transmits the detected rotation speed to the control unit 27 . The controller 27 may compensate for the speed change of the second drive source 22 by controlling the voltage or current supplied to the second drive source 22 in consideration of the speed change of the second drive source 22 .

The torque limiter 111 provides a threshold torque at which the driven rotation of the first conveying roller 11 is initiated by the second conveying roller 12 . That is, the torque limiter 111 selectively permits the driven rotation of the first conveying roller 11 by the second conveying roller 12 according to the magnitude of the load torque acting on the first conveying roller 11 . When the load torque applied to the first conveying roller 11 exceeds the threshold torque provided by the torque limiter 111 , the first driving force in the second direction B2 transmitted to the first conveying roller 11 is blocked and the second The first conveying roller 11 is allowed to be driven and rotated in the third direction B3 by the second conveying roller 12 . When the load torque applied to the first transfer roller 11 is smaller than the threshold torque provided by the torque limiter 111 , the first transfer roller 11 is rotated in the second direction B2 by the first driving force.

The separation action by the first transfer roller 11 and the second transfer roller 12 will be briefly described.

When there is no paper P or only one sheet of paper P is drawn between the second conveying roller 12 and the first conveying roller 11, the load torque applied to the first conveying roller 11 is the torque limiter ( 111 ), the driving force to the first conveying roller 11 is blocked by the torque limiter 111 . Accordingly, the first conveying roller 11 is rotated in the third direction B3 for conveying the paper P in the take-out direction A1 together with the second conveying roller 12 .

When two or more sheets of paper, for example, the paper P1 and the paper P2 are inserted between the second conveying roller 12 and the first conveying roller 11, the paper P1 and the paper P2 are respectively It is in contact with the second conveying roller 12 and the first conveying roller 11 . At this time, the frictional force between the paper P1 and the paper P2 is smaller than the frictional force between the paper P2 and the first conveying roller 11 . Accordingly, slip occurs between the paper P1 and the paper P2 , and the load torque applied to the first conveying roller 11 is smaller than the threshold torque provided by the torque limiter 111 . The first conveying roller 11 is rotated in the second direction B2 , and the paper P2 is conveyed by the first conveying roller 11 in the reverse direction A2 of the take-out direction A1 . Accordingly, only the paper P1 passes between the second conveying roller 12 and the first conveying roller 11 and is conveyed in the take-out direction A1.

When two or more sheets of paper are inserted between the second conveying roller 12 and the first conveying roller 11, the second conveying roller 12 is rotated in the first direction by the second driving source 22, 1 The conveying roller 11 is rotated in the second direction by the first driving source 21 .

Referring back to FIGS. 1 and 2 , the second conveying roller 12 is connected to the second driving source 22 by a second power transmitting structure 32 , and the first conveying roller 11 transmits the first power It is connected to the first driving source 21 by the structure 31 .

The first power transmission structure 31 may include at least one first rotation member 310 (refer to FIG. 6 ). The second power transmission structure 32 may include at least one second rotation member 320 (refer to FIG. 5 ).

The first power transmission structure 31 and the second power transmission structure 32 may have a structure in which at least some regions are connected by a belt transmission method.

For example, the first power transmission structure 31 includes a plurality of pulleys 311 , 311A, 311B, 311C, and 311D that rotate in association with the rotation of the first driving source 21 , and a plurality of pulleys 311 . It may include a belt 312 (312A, 312B) wound around at least a portion. The first rotation member 310 may be any one of the pulleys 311A, 311B, 311C, and 311D and the belts 312A and 312B. For example, the first rotation member 310 may be a pulley 311C.

For stable driving force transmission, a plurality of projections are disposed on the outer peripheral surface of the pulley 311 of the first power transmission structure 31 , and the plurality of projections are inserted on the inner surface of the belt 312 of the first power transmission structure 31 . A plurality of possible grooves can be arranged.

For example, the second power transmission structure 32 includes a plurality of pulleys 321 rotating in association with the rotation of the second driving source 22 , and a belt 322 wound around at least a portion of the plurality of pulleys 321 . and a rotation shaft 323 that rotatably supports at least one of the plurality of pulleys 321 and extends in a direction perpendicular to the paper withdrawal direction. The second rotation member 320 may be any one of a pulley 332 , a belt 322 , and a rotation shaft 323 . For example, the second rotation member 320 may be a rotation shaft 323 .

For stable driving force transmission, a plurality of projections are disposed on the outer peripheral surface of the pulley 321 of the second power transmission structure 32 , and the plurality of projections are inserted on the inner surface of the belt 322 of the second power transmission structure 32 . A plurality of possible grooves can be arranged.

However, the configuration of the first and second power transmission structures 31 and 32 is not limited thereto, and when another power transmission method, for example, a chain transmission method, a friction transmission method, or a gear transmission method is applied, different It may be changed to a configuration or may further include it.

The second power transmission structure 32 may transmit a portion of the second driving force to the other conveying rollers 15 . For example, the second power transmitting structure 32 may transmit the second driving force to the other conveying roller 15 through the additional pulley 325 and the belt 326 .

With the above configuration, the first driving source 21 rotates the first conveying roller 11 in the second direction B2, and the second driving source 22 includes the second conveying roller 12 and other conveying rollers. (15) can be rotated in the first direction (B1). Accordingly, some sheets of paper P1 are conveyed along the take-out direction A1 by the second conveying roller 12 and the other conveying rollers 15 , and some sheets of paper P2 are conveyed by the first conveying roller 11 . It is transported along a direction A2 opposite to the withdrawal direction A1.

However, while the paper P is conveyed in the drawing direction A1 or the direction A2 opposite to the drawing direction A1 by the conveying rollers, load torque may be unintentionally concentrated on some conveying rollers.

4 is a view for explaining a state when a load torque is concentrated on some conveying rollers.

4, when the state of the paper P2 such as the thickness, material, or surface friction of the paper P1 and P2 is different from the previous paper P1, the first conveying roller 11 in contact with the paper P2 ) may unintentionally apply a large load torque. Thereby, the rotational speed of the first conveying roller 11 can be lowered at least temporarily. In other words, even if the rotational speed of the first conveying roller 11 is managed by the control unit 27, due to the unintended load torque, the first conveying roller 11 may temporarily out of the reference speed range and become small. can At this time, the load torque applied to the second transfer roller 12 may be smaller than the load torque applied to the first transfer roller 11 .

Due to this unintended load torque, when the rotational speed of the first conveying roller 11 is reduced, the paper conveying apparatus 1 according to the embodiment has a second conveying roller 12 with a relatively small decrease in speed. By using the driving force to drive the first transfer roller 11 may have a structure that minimizes a decrease in the rotational speed.

The paper conveying apparatus 1 according to the embodiment may further include an optional power transmission structure 100 for connecting the first conveying roller 11 to the second driving source 22 when a predetermined condition is satisfied. .

In the selective power transmission structure 100 , when the rotational speed of the first conveying roller 11 is about to fall below a predetermined reference speed, the rotational speed of the first conveying roller 11 is lowered by a simple mechanical structure. can be configured to prevent

FIG. 5 is an enlarged perspective view of a part of the paper transport device 1 of FIG. 1 , and FIG. 6 is a side view of a part of the paper transport device 1 of FIG. 1 as viewed from the side.

5 and 6 , the selective power transmission structure 100 moves between the first power transmission structure 31 and the second power transmission structure 32 based on the rotational speed of the first transfer roller 11 . Optionally, the second driving force may be selectively transmitted to the first conveying roller 11 .

The optional power transmission structure 100 includes a connection rotation member 110 that rotates in association with the first power transmission structure 31 , and a one-way arrangement between the connection rotation member 110 and the second power transmission structure 32 . A one-way bearing 130 may be included.

The connecting rotation member 110 may rotate in association with the first rotation member 310 . The one-way bearing 130 may be disposed between the connecting rotation member 110 and the second rotation member 320 .

The one-way bearing 130 allows the rotation of the connection rotation member 110 with respect to the second rotation member 320 when the rotation speed of the connection rotation member 110 is greater than the speed of the second rotation member 320 . .

The one-way bearing 130 blocks rotation of the connection rotation member 110 with respect to the second rotation member 320 when the rotation speed of the connection rotation member 110 is less than the speed of the second rotation member 320 . As the rotation of the connection rotation member 110 with respect to the second rotation member 320 is blocked, the rotation member 110 is rotated by the second rotation member 320 , and a portion of the second driving force is the first power. It is transferred to the transfer structure 31 .

The connection rotation member 110 includes a first connection rotation member 111 interlocking with the pulleys 311B and 311C of the first power transmission structure 31 and a first connection rotation member 111 by the connection member 113 . It may include a second connection rotation member 112 connected to.

The second connecting rotation member 112 may be installed on the rotation shaft 323 of the second power transmission structure 32 by the one-way bearing 130 .

The first connecting rotary member 111 and the second connecting rotary member 112 may have a pulley shape, and the connecting member 113 may have a belt shape. As an example, the first connecting rotating member 111 and the second connecting rotating member 112 may be pulleys having a plurality of protrusions formed on an outer circumferential surface, and the connecting member may be a belt having a plurality of grooves formed on an inner surface thereof.

The first connection rotation member 111 may be disposed to be fixed coaxially with at least one of the pulleys of the first power transmission structure 31 . The first connecting rotation member 111 and the pulleys 311B and 311C of the first power transmission structure 31 may be rotated together.

The second connecting rotation member 112 may be disposed coaxially with at least one pulley 321B among the pulleys 321 of the second power transmission structure 32 . For example, the second connecting rotation member 112 may be disposed coaxially to the pulley 321B of the second power transmission structure 32 through the rotation shaft 323 of the second power transmission structure 32 .

In order to prevent slipping between the rotation shaft 323 of the second power transmission structure 32 and the pulley 321B of the second power transmission structure 32 , the rotation shaft 323 and this rotation shaft 323 are inserted The cross-sectional shape of the insertion hole of the pulley 321B may not be circular. For example, as shown in FIG. 7 , the cross-sectional shape of the insertion hole of the rotation shaft 323 and the pulley 321B may be a D-shape.

The one-way bearing 130 may prevent the rotation speed of the second connection rotation member 112 from being lower than the rotation speed of the rotation shaft 323 . The second driving force may be selectively transmitted to the first power transmission structure 31 according to a relationship between the rotation speed of the second connection rotation member 112 and the rotation speed of the rotation shaft 323 . In a normal state, that is, when an unintentional load torque does not act on the first driving source 21 , the rotation speed of the second connecting rotation member 112 rotating in conjunction with the first driving source 21 is determined by the rotation shaft 323 . ) can be set to be greater than the rotation speed of

FIG. 8 is a view for explaining the operation of the one-way bearing 130 in the paper transport device 1 of FIG. 5 .

Referring to FIG. 8 , the one-way bearing 130 installed on the second connecting rotary member 112 may be installed to be rotatable in one direction (direction A) but not to rotate in the opposite direction (direction B). . By the one-way bearing 130 , the second driving force for rotating the rotating shaft 323 is selectively transmitted to the second connecting rotating member 112 .

When the rotation speed V11 of the second connection rotation member 112 is greater than the rotation speed V2 of the rotation shaft 323 , the second connection rotation member 112 is rotated in one direction A with respect to the rotation shaft 323 . direction) is the force acting on it. At this time, since the one-way bearing 130 is rotatable in one direction (direction A), the second connection rotation member 112 and the rotation shaft 323 have respective speeds V11 and V2 without a separate driving force transmission. ) will rotate according to

On the other hand, when the rotation speed V11 of the second connection rotation member 112 is lowered than the rotation speed V2 of the rotation shaft 323 , the second connection rotation member 112 is rotated with respect to the rotation shaft 323 . The force acts in the opposite direction (direction B). At this time, since the one-way bearing 130 does not allow rotation in the opposite direction (direction B), a driving force transmission occurs between the rotation shaft 323 and the second connecting rotation member 112 . When the second driving force for rotating the rotation shaft 323 is greater than the force transmitted through the second connection rotation member 112 , the second connection rotation member 112 rotates together with the rotation shaft 323 . That is, the second connecting rotation member 112 rotates in the same direction and at the same speed as the rotation shaft 323 .

The second driving force transmitted to the second connection rotating member 112 is transmitted to the first conveying roller 11 . As such, the first conveying roller 11 on which the load torque is relatively concentrated has the fastest speed among the first drive source 21 or the second drive source 22 through the selective power transmission structure 100 that is a mechanical configuration. connected to the drive source.

Accordingly, by the second driving force transmitted to the first power transmission structure 31 , an unintended load torque applied to the first conveying roller 11 can be offset to some extent, and the first conveying roller 11 . can compensate for the slowdown of That is, the paper conveying apparatus 1 according to the embodiment may prevent the rotational speed of the first conveying roller 11 from falling below the reference speed through the selective power transmission structure 100 which is a mechanical configuration. The paper conveying device 1 may implement uniform paper conveying without installing an additional motor or installing complex firmware.

On the other hand, in the above-described embodiment, the selective power transmission structure 100 is mainly connected to the first power transmission structure 31 by the first and second connecting rotation members 111 and 112 and the connecting member 113 . explained. However, the selective power transmission structure 100 may be variously modified as long as the power transmission between the first power transmission structure 31 and the second power transmission structure 32 is selectively made. For example, as shown in FIG. 9 , in the selective power transmission structure 100 , the second connection rotation member 112 installed on the rotation shaft 323 is different without the first connection rotation member 111 and the connection member 113 . It may be connected to the first power transmission structure 31 by the connecting member 114 .

In the above-described embodiment, the one-way bearing 130 has been described focusing on an example in which the second connecting rotation member 112 and the rotation shaft 323 are installed. However, the arrangement of the one-way bearing 130 is not limited thereto, and may be variously applied as necessary. Although not shown, different from the above embodiment, the one-way bearing 130 may be disposed on the first connecting rotary member 111 , and the second connecting rotary member 112 may be coaxially fixed to the rotary shaft 323 . . In this case, power transmission between the first connection rotation member 111 and the first power transmission structure 31 may be selectively performed according to the speed of the first connection rotation member 111 .

10 is a schematic configuration diagram of an embodiment of a scanner device 600 in which the paper transport device 1 is employed. Referring to FIG. 10 , the scanner device 600 includes a media processing unit that reads an image while transferring the paper P supplied from the paper feeding device to which the paper feeding device 1 is applied.

The media processing unit may include a paper transfer unit 600a and a reading unit 600b that reads an image from the paper. As the paper conveying apparatus 1, the paper conveying apparatus 1 described in Figs. 1 to 9 is employed. Since the scanner device 600 reads an image recorded on the paper P, the paper transport device 1 transports the paper P.

A reading member 650 for reading an image from the paper P is provided in the reading unit 600b. The reading member 650 irradiates light to the paper P and receives the light reflected from the paper P to read the image of the paper P. As the reading member 650 , for example, a contact type image sensor (CIS), a charge coupled device (CCD), or the like may be employed.

The scanner device 600 is a flatbed that reads an image while the paper P is positioned at a fixed position and a reading member such as a contact type image sensor (CIS) or a charge coupled device (CCD) is moved. ) method, a document feed method in which the reading member is positioned at a fixed position and the paper P is conveyed, and a combination method thereof. The scanner device 600 of the present embodiment is a scanner device of a complex type in which a flat bed method and a paper transport method are combined.

The reading unit 600b is provided with a platen glass 660 on which the paper P is placed in order to read an image from the paper P in a flatbed manner. In addition, the reading unit 600b is provided with a reading window 670 for reading an image from the paper P by a paper transfer method. The reading window 670 may be, for example, a transparent member. As an example, the upper surface of the reading window 670 may be the same height as the upper surface of the platen glass 660 .

When the paper transfer method is applied, the reading member 650 is positioned below the reading window 670 . When the flat bed method is applied, the reading member 650 may be moved under the platen glass 660 in the sub-scan direction S, that is, in the longitudinal direction of the paper P, by a moving means not shown. . In addition, when the flatbed method is applied, it is necessary to expose the platen glass 660 to the outside in order to place the paper P on the platen glass 660 . To this end, the paper transfer unit 600a may be rotated with respect to the reading unit 600b to expose the platen glass 660 .

The paper transfer unit 600a transfers the paper P so that the reading member 650 can read the image recorded on the paper P, and discharges the paper P on which the reading is completed. To this end, the paper transfer path 610 is provided in the paper transfer unit 600a, and the reading member 650 reads an image from the paper P transferred along the paper transfer path 610 . The paper transport path 610 may include, for example, a supply path 611 , a reading path 612 , and an exhaust path 613 . A reading member 650 is disposed in the reading path 612 , and the image recorded on the paper P is read by the reading member 650 while passing through the reading path 612 . The supply path 611 is a path for supplying the paper P to the reading path 612 , and the paper P loaded on the loading table 10 is supplied to the reading path 612 through the supply path 611 . do. The discharge path 613 is a path for discharging the paper P that has passed through the reading path 612 . Accordingly, the paper P loaded on the loading table 10 is transported along the supply path 611 , the reading path 612 , and the discharge path 613 , and is discharged to the discharge tray 630 .

In the paper transport path 610 , transport rollers 621 and 622 for transporting the paper P drawn out from the loading table 10 by the paper transport device 1 may be disposed. Each of the conveying rollers 621 and 622 may have a structure in which a driving roller and a driven roller are engaged with each other and rotated.

Transport rollers 623 and 626 for transporting the paper P may be disposed on the reading path 612 . For example, conveying rollers 623 and 626 for conveying the paper P may be disposed on both sides of the reading member 650 as a reference. Each of the conveying rollers 623 and 626 may have a structure in which a driving roller and a driven roller are engaged with each other and rotated. A reading guide member 624 opposite to the reading member 650 is disposed in the reading path 612 . The reading guide member 624 is pressed against the reading window 670 by its own weight or by the elastic member 625 , and the paper P is transferred between the reading window 670 and the reading guide member 624 . Although not shown in the drawings, a reading roller may be employed instead of the reading guide member 624 , which is elastically pressed against the reading window 670 and rotates, and conveys the paper P supplied therebetween.

A discharge roller 627 for discharging the paper P on which reading has been completed is disposed in the discharge path 613 . The discharge roller 627 may have a structure in which a driving roller and a driven roller are engaged with each other and rotated.

With this configuration, the paper P supplied from the paper conveying device 1 is conveyed along the supply path 611, the reading path 612, and the discharge path 613, and the reading member 650 is the paper ( The image can be read from P).

11 is a schematic configuration diagram of an image forming apparatus 700 employing the paper transfer apparatus 1 according to an embodiment. Referring to FIG. 11 , a printing unit (media processing unit) 700a for printing an image on paper P supplied from a paper feeding device is provided. As shown by a solid line in FIG. 11 , the paper feeding device may be positioned under the printing unit 700a in the form of a cassette feeding device 1b to which the paper feeding device 1 is applied. In addition, as shown by a dotted line in FIG. 11 , the paper transport device 1 may be applied to a multi-purpose tray (MPT) 1c positioned on one side of the printing unit 700a.

The printing unit 700a of the present embodiment may print an image on the paper P by various methods such as an electrophotographic method, an inkjet method, a thermal transfer method, a thermal sublimation method, and the like. The image forming apparatus of this embodiment prints a color image on the paper P by the electrophotographic method. Referring to FIG. 14 , the printing unit 700a may include a plurality of developing units 710 , an exposure unit 720 , a transfer unit, and a fixing unit 740 .

For color printing, the plurality of developing units 710 are configured to develop images of, for example, cyan (C: cyan), magenta (M: magenta), yellow (Y: yellow), and black (K: black) colors. Four developing units 710 may be included. Each of the four developing units 710 may contain toners of cyan (C: cyan), magenta (M: magenta), yellow (Y: yellow), and black (K: black) colors. The printing unit 700a may further include a developing unit 710 for accommodating and developing toners of various colors such as light magenta and white in addition to the above-described colors.

The developing device 710 includes a photosensitive drum 7a. The photosensitive drum 7a is an example of a photosensitive member on which an electrostatic latent image is formed on its surface, and may include a conductive metal pipe and a photosensitive layer formed on its outer periphery. The charging roller 7c is an example of a charging machine that charges the photosensitive drum 7a to have a uniform surface potential. The cleaning blade 7d is an example of a cleaning means for removing toner and foreign substances remaining on the surface of the photosensitive drum 7a after a transfer process to be described later.

The developing unit 710 supplies the toner contained therein to the electrostatic latent image formed on the photosensitive drum 7a to develop the electrostatic latent image into a visible toner image. As the developing method, there are a one-component developing method using a toner and a two-component developing method using a toner and a carrier. The developing device 710 of this embodiment employs a one-component developing method. The developing roller 7b is for supplying toner to the photosensitive drum 7a. A developing bias voltage for supplying toner to the photosensitive drum 7a may be applied to the developing roller 7b.

The one-component developing method is a contact developing method in which the developing roller 7b and the photosensitive drum 7a are in contact with each other and rotated, and the developing roller 7b and the photosensitive drum 7a are positioned to be spaced apart by tens to hundreds of microns from each other and rotated. It can be classified as a non-contact development method. The supply roller 7e supplies the toner in the developing device 710 to the surface of the developing roller 7b. A supply bias voltage for supplying the toner in the developing unit 710 to the surface of the developing roller 7b may be applied to the supply roller 7e.

The exposure machine 720 irradiates light modulated in correspondence with the image information to the photosensitive drum 7a to form an electrostatic latent image on the photosensitive drum 7a. As the exposure machine 710 , a laser scanning unit (LSU) using a laser diode as a light source, an LED exposure machine using a light emitting diode (LED) as a light source, or the like may be employed.

The transfer machine may include an intermediate transfer belt 731 , a primary transfer roller 372 , and a secondary transfer roller 733 . The toner image developed on the photosensitive drum 7a of the four developing units 710 is temporarily transferred to the intermediate transfer belt 731 . The intermediate transfer belt 731 is supported by the support rollers 734, 735, and 736 and circulated. Four primary transfer rollers 732 are disposed at positions facing the photosensitive drums 7a of the four developing devices 710 with the intermediate transfer belt 731 interposed therebetween. A primary transfer bias voltage for primary transfer of the toner image developed on the photosensitive drum 7a to the intermediate transfer belt 731 is applied to the four primary transfer rollers 732 . The secondary transfer roller 733 is positioned to face the intermediate transfer belt 731 . A secondary transfer bias voltage is applied to the secondary transfer roller 733 to transfer the toner image primary transferred to the intermediate transfer belt 731 to the paper P.

When a print command is received from a host (not shown) or the like, a control unit (not shown) (not shown) charges the surface of the photosensitive drum 7a to a uniform electric potential using a charging roller 7c. The exposure machine 720 scans the four light beams modulated to match the image information of each color to the photosensitive drums 7a of the four developing devices 710 to form an electrostatic latent image on the photosensitive drums 7a. The developing roller 7b supplies C, M, Y, and K toners to the corresponding photosensitive drums 7a, respectively, to develop the electrostatic latent image into a visible toner image. The developed toner images are primarily transferred to an intermediate transfer belt 731 . The paper P from the paper feeding device 1b or 1c is transferred to the transfer nip formed by the secondary transfer roller 733 and the intermediate transfer belt 731 . The toner images transferred primarily on the intermediate transfer belt 731 are transferred to the paper P by the secondary transfer bias voltage applied to the secondary transfer roller 733 . When the paper P passes through the fixing unit 740 , the toner images are fixed to the paper P by heat and pressure. The fixed paper (P) is discharged to the outside by the discharge roller (750).

The scanner apparatus 600 and the image forming apparatus 700 may be used alone or in the form of a multifunction device combined with each other. 12 is a schematic diagram of an embodiment of a multifunction peripheral.

Referring to FIG. 12 , the scanner 600 is disposed on the printing unit 700a. The structures of the scanner 600 and the printing unit 700a are the same as those shown in FIGS. 10 and 11 . The paper conveying device 1 for supplying the paper P to the printing unit 700a may be implemented in various forms. For example, the embodiments of the paper transport device 1 shown in FIGS. 1 to 9 are a multi-purpose tray positioned on the side of the printing unit 700a as shown in FIG. 11 , as shown in FIG. 12 . A main cassette feeder 810 installed under the print unit 700a, a secondary cassette feeder installed under the main cassette feeder 810 ( 820, a high capacity feeder 830 installed under the main cassette feeder 810 or under a secondary cassette feeder 820, or a print unit It can be applied to the high capacity feeder (840) installed on the side (700a).

Meanwhile, in the above-described embodiments, the description has been focused on an example in which the paper feeder is applied to the paper feeder. However, the paper conveying device is not limited thereto, and may be applied in various ways as long as it is a device for conveying paper in addition to the paper feeding device.

The above-described embodiments are merely exemplary, and various modifications and equivalent other embodiments are possible by those skilled in the art. Therefore, the true technical protection scope of the present invention will have to be determined by the technical idea of the invention described in the following claims.

Claims (15)

first and second conveying rollers;
a first driving source for generating a first driving force for rotationally driving the first conveying roller;
a second driving source for generating a second driving force for rotationally driving the second conveying roller;
a first power transmitting structure configured to transmit the first driving force to the first conveying roller;
a second power transmitting structure configured to transmit the second driving force to the second conveying roller; and
Selective power configured to selectively connect between the first power transmission structure and the second power transmission structure based on the rotational speed of the first conveying roller, and the second driving force is selectively transmitted to the first conveying roller A paper conveying device, including; a conveying structure. According to claim 1,
The first power transmission structure includes at least one first rotating member,
The second power transmission structure includes at least one second rotating member,
The selective power transmission structure includes a connecting rotating member that rotates in association with the first rotating member, and a one-way bearing disposed between the connecting rotating member and the second rotating member. 3. The method of claim 2,
The one-way bearing is
When the rotation speed of the connecting rotation member is greater than the speed of the second rotation member, allowing rotation of the connection rotation member with respect to the second rotation member,
and blocking rotation of the connecting rotating member with respect to the second rotating member when the rotational speed of the connecting rotating member is smaller than the speed of the second rotating member. 4. The method of claim 3,
When the rotation speed of the connection rotation member is smaller than the speed of the second rotation member, the connection rotation member is rotated by the second rotation member, and a portion of the second driving force is transmitted to the first power transmission structure , paper feeder. 3. The method of claim 2,
The second power transmission structure,
a plurality of pulleys rotated in association with the rotation of the second driving source;
a belt wound around at least a portion of the plurality of pulleys;
A paper conveying apparatus comprising a rotation shaft rotatably supporting at least one of the plurality of pulleys and extending in a direction perpendicular to a paper withdrawal direction. 6. The method of claim 5,
The connecting rotating member is installed to be rotatable in one direction on the rotating shaft by the one-way bearing. 6. The method of claim 5,
The insertion hole of the pulley into which the rotation shaft is inserted and the cross-sectional shape of the rotation shaft have a D-shape. 6. The method of claim 5,
a plurality of projections disposed on the outer peripheral surface of the pulley;
A paper conveying apparatus disposed on the inner surface of the belt and having a plurality of grooves into which the plurality of projections can be inserted. According to claim 1,
The first driving source is a DC motor whose speed is variable according to a change in the magnitude of the applied load torque. According to claim 1,
The first driving source is a brush DC motor or a brushless DC motor. 10. The method of claim 9,
a first detection unit for detecting the rotational speed of the first driving source;
Based on the detected rotation speed, the paper conveying apparatus further comprising a control unit for controlling the voltage or current applied to the first driving source. According to claim 1,
The first conveying roller is configured to rotate in a direction opposite to the paper take-out direction,
and the second conveying roller is configured to rotate in a paper take-out direction. According to claim 1,
and a torque limiter selectively allowing driven rotation of the first conveying roller by the second conveying roller according to the magnitude of the load torque acting on the first conveying roller. The paper conveying device according to claim 1; and
A scanner device comprising a; a reading unit for reading an image from a manuscript. The paper conveying device according to claim 1; and
A printing unit for printing an image on paper; including, an image forming apparatus.

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