JP7151334B2 - Conveying device and image recording device - Google Patents

Description

The present invention relates to a conveying device that conveys a sheet along a conveying path, and an image recording apparatus that includes the conveying device and is capable of recording an image on the sheet.

A conveying device that conveys a sheet along a conveying path is known. 2. Description of the Related Art An image recording apparatus that records an image on a sheet is an example of an apparatus that includes a conveying device. A plurality of rollers for conveying sheets are arranged at intervals in the conveying path of the conveying device.

In view of the recent demands for downsizing and cost reduction of conveying devices, it is preferable that the number of motors mounted on the conveying device is small. Therefore, like the conveying devices disclosed in Patent Documents 1 and 2, it is preferable that the plurality of rollers be driven by a common motor.

The conveying devices disclosed in Patent Documents 1 and 2 include a first roller pair having a first roller to which drive is transmitted from a motor, and a first roller pair located downstream of the first roller pair in the sheet conveying direction. and a second roller pair having a second roller to which drive is transmitted from the roller via a belt or the like. Further, the conveying device has a one-way clutch on the drive transmission path from the first roller to the second roller. As a result, forward rotation of the motor is transmitted from the first roller to the second roller, but reverse rotation of the motor is not transmitted from the first roller to the second roller. As a result, when the preceding sheet is nipped by the second roller pair and the skew of the subsequent sheet is corrected by the first roller pair or the motor is reversed to drive other rollers, It is possible to prevent the preceding sheet from being reversed.

JP 2013-203503 A JP 2017-65892 A

However, the transport devices disclosed in Patent Documents 1 and 2 may have the following problems. In a state in which the sheet is sandwiched by both the first roller pair and the second roller pair, the sheet is conveyed in the conveying direction. A force acting momentarily in the conveying direction acts from the sheet to the second roller. As a result, the amount of rotation of the second roller momentarily becomes larger than the amount of rotation of the first roller. Then, the inner ring of the one-way clutch rotates integrally with the shaft of the second roller, and the one-way clutch is in a state in which the drive transmission from the first roller to the second roller is released. After that, the forward rotation of the motor is transmitted from the first roller to the outer ring of the one-way clutch, and the outer ring rotates, whereby the one-way clutch returns to a state in which drive can be transmitted from the first roller to the second roller.

However, during the rotation of the outer ring, the inner ring does not rotate until the one-way clutch returns to a state in which the drive can be transmitted from the first roller to the second roller. As a result, a phase difference occurs between the inner ring and the outer ring of the one-way clutch. As a result, when the sheet is conveyed thereafter, a discrepancy occurs between the sheet conveying amount ascertained from the rotation amount of the motor calculated by a rotary encoder or the like and the actual sheet conveying amount.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conveying apparatus capable of preventing deviation of the conveying amount of a sheet due to the occurrence of a phase difference in a one-way clutch.

(1) The conveying device of the present invention is positioned on a sheet conveying path with a forward and reverse motor, and conveys the sheet in the conveying direction by transmitting one of the forward and reverse rotations of the motor. a first roller pair having a first roller that rotates in the opposite direction to convey the sheet in a direction opposite to the conveying direction when the other of forward rotation or reverse rotation of the motor is transmitted; a second roller pair having a second roller positioned downstream of the first roller in the conveying direction; and a first transmission section capable of transmitting rotation of the motor from the first roller to the second roller. Prepare. the first transmission unit having a one-way clutch that transmits one of the forward rotation and reverse rotation of the motor to the second roller and does not transmit the other of the forward rotation and reverse rotation of the motor to the second roller; The second roller, which is provided between the rotating body and the second roller in the transmission path of the rotation of the motor and rotates in a direction for conveying the sheet in the conveying direction, is rotated by a predetermined amount with respect to the rotating body. and an idling part for idling. The predetermined amount is rotated by a force acting from the sheet sandwiched between the first roller pair and the second roller pair when the sheet is conveyed in the conveying direction and passes through the first roller pair. larger than the amount of rotation of the second roller.

In a state in which the sheet is nipped by both the first roller pair and the second roller pair, the sheet is conveyed, and when the upstream end of the sheet in the conveying direction leaves the first roller pair, the sheet is instantaneously An acting transport-oriented force acts from the sheet to the second roller. This force momentarily rotates the second roller. Here, the predetermined amount by which the idling portion can idly rotate the second roller with respect to the rotating body is greater than the amount of rotation of the second roller caused by the momentary rotation. Therefore, the second roller idles with respect to the rotating body. Therefore, since the inner ring of the one-way clutch does not rotate, the one-way clutch is maintained in a state in which drive transmission from the first roller to the second roller is possible. In other words, no phase difference occurs between the inner ring and the outer ring of the one-way clutch. After that, when the forward rotation of the motor is transmitted from the first roller to the outer ring of the one-way clutch and the outer ring rotates, the inner ring and the second roller of the one-way clutch also rotate.

According to the present invention, since no phase difference occurs in the one-way clutch, it is possible to prevent deviation of the conveying amount of the sheet due to the occurrence of the phase difference.

FIG. 1 is a perspective view of the multifunction device 10. FIG. FIG. 2 is a longitudinal sectional view schematically showing the internal structure of the printer section 11. As shown in FIG. FIG. 3 is a plan view of the carriage 23 and guide rails 43 and 44. FIG. 4A and 4B are schematic diagrams of the transmission section 74 and the transmission section 85, in which (A) shows a state in which the carry motor 102 is rotated forward, and (B) shows a state in which the carry motor 102 is rotated in reverse. 5 is a plan view of the drive transmission mechanism 70 and the rollers 60, 62. FIG. FIG. 6 is a block diagram of the printer section 11. As shown in FIG. FIG. 7 is a schematic cross-sectional view of the periphery of the pulley 78 with the roller 113 sandwiched between the first surface 115 and the outer peripheral surface 112A. FIG. 8 is a schematic cross-sectional view of the periphery of the pulley 78 with the roller 113 sandwiched between the second surface 116 and the outer peripheral surface 112A. FIG. 9 is a schematic cross-sectional view of the periphery of pulley 78 with protrusion 117 separated from side surface 118B. FIG. 10 is a flowchart of image recording processing. FIG. 11 is a longitudinal sectional view schematically showing the internal structure of the printer section 11 with the preceding sheet 12A at a predetermined position. FIG. 12 is a schematic cross-sectional view of a pulley 78 having three protrusions 117 and its periphery.

Embodiments of the present invention will be described below. It should be noted that the embodiment described below is merely an example of the present invention, and it goes without saying that the embodiment of the present invention can be changed as appropriate without changing the gist of the present invention. In the following description, the vertical direction 7 is defined with reference to the state in which the multifunction device 10 is installed for use (the state shown in FIG. 1), and the front-rear direction 8 is defined with the surface on which the opening 13 is provided as the front surface 104. A left-right direction 9 is defined when the MFP 10 is viewed from the front to the rear. The up-down direction 7, the front-rear direction 8, and the left-right direction 9 are orthogonal to each other. In this embodiment, the up-down direction 7 corresponds to the vertical direction, and the front-rear direction 8 and the left-right direction 9 correspond to the horizontal direction.

[Overall Configuration of MFP 10]
As shown in FIG. 1, a multi-function device 10 (an example of an image recording device) is generally shaped like a rectangular parallelepiped. The multi-function device 10 has a printer section 11 for recording an image on a sheet 12 (an example of a sheet, see FIG. 2) using an inkjet recording method. The MFP 10 has various functions such as a facsimile function and a print function. Note that the printer unit 11 may record an image on the paper 12 by, for example, an electrophotographic method other than the inkjet recording method.

As shown in FIG. 2, the printer section 11 includes a conveying device, a recording section 24, and a platen . The conveying device includes a feeding unit 15, a feeding tray 20 (an example of a tray), a discharge tray 21, a pair of conveying rollers 54 (an example of a first roller pair), and a pair of discharge rollers 55 (an example of a second roller pair). an example), a conveying motor 102 (an example of a motor, see FIG. 6), and a drive transmission mechanism 70 (see FIG. 6).

[Feed tray 20, discharge tray 21]
As shown in FIGS. 1 and 2, the feed tray 20 is inserted rearward through an opening 13 formed in the front of the printer section 11 and removed forward. The feed tray 20 supports a plurality of stacked sheets 12 . The discharge tray 21 is positioned above the feed tray 20 . The discharge tray 21 supports the paper 12 discharged by the discharge roller pair 55 through the opening 13 .

[Feeding unit 15]
As shown in FIG. 2 , the feeding section 15 includes a feeding roller 25 , a feeding arm 26 and a shaft 27 . The feed roller 25 is rotatably supported by the tip of the feed arm 26 . The feed roller 25 rotates in a direction to transport the paper 12 supported on the feed tray 20 backward by the reverse rotation of the transport motor 102 (see FIG. 6), thereby feeding the paper 12 to the transport path 65 described later. send. The paper 12 fed to the transport path 65 is transported in the transport direction 16 along the transport path 65 . The conveying direction 16 is the direction along the conveying path 65 and is indicated by the dashed-dotted arrow in FIG. The paper 12 transported in the transport direction 16 by the feed tray 20 is directed to the transport roller pair 54 positioned on the transport path 65 . The feeding arm 26 is rotatably supported by a shaft 27 supported by the frame of the printer section 11 .

[Conveyance path 65]
As shown in FIG. 2, a transport path 65 through which the paper 12 passes is formed inside the printer section 11 . The transport path 65 refers to a space formed by the guide members 18 and 19 facing each other at a predetermined interval inside the printer section 11 and a space formed by the recording section 24 and the platen 42 .

The conveying path 65 is composed of a curved conveying path and a linear conveying path that extends linearly. The curved transport path is a path that extends upward from the bottom at the rear of the printer section 11 and makes a U-turn. The linear transport path is a path from the transport roller pair 54 to the discharge tray 21 via the recording unit 24 . Further, the transport roller pair 54 and the discharge roller pair 55 according to this embodiment are positioned on the straight transport path of the transport path 65 .

It should be noted that the transport path 65 is not limited to the configuration of the curved transport path and the straight transport path as shown in FIG. For example, the transport path 65 may consist of only a straight transport path.

[Conveyance Roller Pair 54 and Discharge Roller Pair 55]
As shown in FIG. 2 , the conveying roller pair 54 is positioned on the straight conveying path of the conveying path 65 . The conveying roller pair 54 includes a conveying roller 60 (an example of a first roller) and a pinch roller 61 facing each other. The transport roller 60 is driven by a transport motor 102 (see FIG. 6). The pinch roller 61 rotates together with the rotation of the conveying roller 60 .

The discharge roller pair 55 is positioned downstream in the transport direction 16 from the transport roller pair 54 in the transport path 65 . The discharge roller pair 55 includes a discharge roller 62 (an example of a second roller) and a spur 63 facing each other. The discharge roller 62 is driven by a conveying motor 102 (see FIG. 6). The spur 63 rotates with the rotation of the discharge roller 62 .

As will be described later, the transport roller 60 and the discharge roller 62 are configured to transport the paper 12 in the transport direction 16 and in the opposite direction (in other words, transport the paper 12 in the direction opposite to the transport direction 16). ). In the following description, among the rotations of the transport roller 60 and the discharge roller 62, rotation in the direction of transporting the paper 12 in the transport direction 16 is referred to as forward rotation. Among the rotations of the conveying roller 60 and the discharge roller 62, forward rotation and reverse rotation are referred to as reverse rotation.

[Recording unit 24]
As shown in FIG. 2 , the recording section 24 is positioned on the straight transport path of the transport path 65 . In this embodiment, the recording unit 24 is positioned between the transport roller pair 54 and the discharge roller pair 55 on the linear transport path.

The recording unit 24 is provided above the platen 42 so as to face the platen 42 . The platen 42 supports the paper 12 transported by the transport roller pair 54 from below. The recording unit 24 has a carriage 23 and a recording head 39 .

As shown in FIG. 3, an ink tube 32 and a flexible flat cable 33 extend from the carriage 23 . The ink tube 32 supplies the ink of the ink cartridge to the recording head 39 . A flexible flat cable 33 electrically connects a control board on which a controller 130 (see FIG. 6) is mounted and the recording head 39 .

The carriage 23 is supported by guide rails 43 and 44 . The guide rails 43 and 44 are spaced apart along the front-rear direction 8 . The guide rails 43 and 44 extend in the left-right direction 9 . Carriage 23 is connected to a known belt mechanism provided on guide rails 44 . The belt mechanism is rotated by being driven by a carriage motor 103 (see FIG. 6). The carriage 23 moves along the left-right direction 9 by the belt mechanism rotating.

As shown in FIG. 2, the recording head 39 is mounted on the carriage 23. As shown in FIG. A plurality of nozzles 40 are formed on the lower surface of the recording head 39 . The recording head 39 ejects ink from nozzles 40 as minute ink droplets. While the carriage 23 is moving, the recording head 39 ejects ink droplets onto the paper 12 supported by the platen 42 . An image is thus recorded on the paper 12 .

[Sensor 120]
As shown in FIG. 2 , the sensor 120 is positioned upstream in the transport direction 16 from the transport roller pair 54 in the transport path 65 . The sensor 120 is a sensor for detecting the existence of the paper 12 at the arrangement position of the sensor 120 . The paper 12 conveyed by the feeding unit 15 passes through the arrangement position of the sensor 120 and reaches the conveying roller pair 54 . The sensor 120 outputs either a high-level signal or a low-level signal (a low-level signal in this embodiment) to the controller 130 (see FIG. 6) when the paper 12 is present at the placement position. On the other hand, the sensor 120 outputs the other of the high level signal and the low level signal (the high level signal in this embodiment) to the controller 130 in response to the fact that the paper 12 is not present at the arrangement position.

[Rotary encoder 121]
As shown in FIG. 2, the printer section 11 includes a known rotary encoder 121 that generates pulse signals according to the rotation of the conveying roller 60. As shown in FIG. The rotary encoder 121 has an encoder disk 123 and an optical sensor 124 . The encoder disk 123 rotates together with the rotation of the transport roller 60 . The optical sensor 124 reads the rotating encoder disk 123 to generate a pulse signal and outputs the generated pulse signal to the controller 130 . Note that the rotary encoder 121 may generate a pulse signal according to the rotation of the transport motor 102 . In this case, the encoder disk 123 is attached to the shaft of the transport motor 102 .

[Drive transmission mechanism 70]
As shown in FIG. 6, the drive transmission mechanism 70 transmits the rotation of the single transport motor 102 to the feed roller 25, transport roller 60, and discharge roller 62. As shown in FIG. The drive transmission mechanism 70 is configured by combining all or part of gears, pulleys, endless annular belts, planetary gear mechanisms, and the like.

As shown in FIGS. 4 and 5, the drive transmission mechanism 70 includes a pulley 71 that rotates integrally with the shaft of the conveying motor 102, a pulley 72 that rotates integrally with the shaft 60A of the conveying roller 60, and a pulley wound around the pulleys 71 and 72. and an endless annular belt 73 suspended thereon. As a result, the forward rotation of the transport motor 102 is transmitted to the transport roller 60 to rotate forward, and the reverse rotation of the transport motor 102 is transmitted to the transport roller 60 to rotate in the reverse direction. The transport roller 60 transports the paper 12 nipped between itself and the pinch roller 61 in the transport direction 16 by rotating forward.

As shown in FIG. 5, the drive transmission mechanism 70 includes transmission units 74 and 85 that transmit the rotation of the transport motor 102 to the feed roller 25 and the discharge roller 62 via the shaft 60A of the transport roller 60. As shown in FIG. However, the specific configuration for transmitting the rotation of the transport motor 102 to the feed roller 25, the transport roller 60, and the discharge roller 62 is not limited to the following example. The transmission portion 74 is an example of a first transmission portion. The transmission section 85 is an example of a second transmission section.

[Transmission unit 74]
The transmission unit 74 shown in FIGS. 4 and 5 transmits forward rotation of the transport motor 102 from the transport roller 60 to the discharge roller 62 . As shown in FIG. 5 , the transmission section 74 is provided to the left of the transport path 65 . That is, the transmission portion 74 transmits the rotation from the left portion of the ejection roller 62 to the ejection roller 62 . Note that the position of the transmission portion 74 is not limited to the position shown in FIG. For example, the transmission section 74 may be provided on the right side of the transport path 65 .

As shown in FIGS. 4 and 5 , the transmission section 74 is composed of gears 75 and 76 that mesh with each other, pulleys 77 and 78 , and an endless annular belt 81 .

The gear 75 meshes with the gear 76 and rotates integrally with the shaft 60A of the conveying roller 60 . The gear 76 and the pulley 77 are coaxial and rotate together.

A pulley 78 (an example of a rotating body) is attached to the outside of the shaft 62A of the discharge roller 62 . Pulley 78 is rotatable around axis 62A. As the pulley 78 rotates, the discharge roller 62 can rotate in conjunction with it. The pulley 78 has a one-way clutch 83 . The one-way clutch 83 rotates the discharge roller 62 integrally with the pulley 78 when forward rotation of the transport motor 102 is transmitted. In other words, the one-way clutch 83 transmits forward rotation of the transport motor 102 transmitted to the pulley 78 to the shaft 62A of the discharge roller 62 . On the other hand, the one-way clutch 83 idles the pulley 78 with respect to the discharge roller 62 when the reverse rotation of the transport motor 102 is transmitted. In other words, the one-way clutch 83 does not transmit the reverse rotation of the transport motor 102 transmitted to the pulley 78 to the shaft 62A of the discharge roller 62 . A detailed configuration of the pulley 78 will be described later.

The belt 81 is wound around pulleys 77 and 78 .

As shown in FIG. 4A, the transmission unit 74 transmits the forward rotation of the transport motor 102 from the transport roller 60 to the discharge roller 62 to rotate the discharge roller 62 forward. The forward rotation of the discharge roller 62 is indicated by an arrow drawn on the outside of the discharge roller 62 . On the other hand, as shown in FIG. 4B, the transmission section 74 does not transmit the reverse rotation of the transport motor 102 from the transport roller 60 to the discharge roller 62 .

As described above, the forward rotation of the transport motor 102 is transmitted to the discharge roller 62 via the transmission unit 74 , so that the discharge roller 62 rotates in the transport direction 16 to transport the paper 12 nipped between it and the spur 63 . As a result, the paper 12 is ejected to the ejection tray 21 .

[Transmission part 85]
The transmission unit 85 shown in FIG. 4 transmits the rotation of the transport motor 102 transmitted via the shaft 60A of the transport roller 60 to the feed roller 25 . As shown in FIG. 4, the transmission section 85 is composed of gears 84, 86 to 91, pulleys 93 to 95, endless annular belts 96, 97, a sun gear 98, a planetary gear 99, and an arm 100. It is configured.

The gear 84 rotates integrally with the shaft 60A. Gear 86 meshes with gear 84 . Gear 87 meshes with gear 86 . The gear 87 and the pulley 92 are coaxial and rotate together. The gear 88 and the pulley 93 coaxially rotate together. Gear 89 meshes with gear 88 . The sun gear 98 coaxially rotates with the gear 89 . Planetary gear 99 meshes with sun gear 98 and moves into and out of gear 90 . The arm 100 has one end rotatably supported by the sun gear 98 and the other end supporting the planetary gear 99 rotatably and revolvingly around the sun gear 98 . As a result, the planetary gear 99 revolves around the sun gear 98 while rotating on its own axis as the sun gear 98 rotates. Gear 90 meshes with gear 91 . The gear 91 and the pulley 94 are coaxial and rotate together. The pulley 95 is coaxial with the feeding roller 25 and rotates integrally. A belt 96 is wound around pulleys 92 and 93 . A belt 97 is wound around pulleys 94 and 95 .

As shown in FIG. 4A , the planetary gear 99 is separated from the gear 90 by transmitting forward rotation of the transport motor 102 to the sun gear 98 . As a result, the transmission unit 85 does not transmit forward rotation of the transport motor 102 to the feed roller 25 . On the other hand, as shown in FIG. 4B, the planetary gear 99 meshes with the gear 90 by transmitting the reverse rotation of the conveying motor 102 to the sun gear 98 . As a result, the transmission unit 85 transmits the reverse rotation of the conveying motor 102 to the feeding roller 25 . As a result, the feeding roller 25 rotates.

[Pulley 78]
As shown in FIG. 7, pulley 78 is provided with one-way clutch 83 . The one-way clutch 83 has an outer ring 111 , an inner ring 112 and rollers 113 .

The outer ring 111 is tubular. A belt 81 is wound around the outer peripheral surface 111A of the outer ring 111 . The inner ring 112 is arranged inside the outer ring 111 . Outer ring 111 and inner ring 112 are rotatable around axis 62A, that is, rotatable in circumferential direction 107 . A gap 110 is formed between the inner ring 112 and the outer ring 111 . A roller 113 is arranged in the gap 110 .

The inner peripheral surface of the outer ring 111 is composed of a plurality of protrusions 114, a first surface 115, and a second surface .

A plurality of protrusions 114 are spaced apart along the circumferential direction 107 of the pulley 78 . In this embodiment, six protrusions 114 are provided, but the number of protrusions 114 is not limited to six. Also, the interval between two adjacent projections 114 may be equal or may be different. The protrusion 114 protrudes radially inward of the pulley 78 , that is, toward the inner ring 112 located on the rotation center side of the pulley 78 .

The first surface 115 and the second surface 116 are located between two protrusions 114 adjacent in the circumferential direction 107 .

The first surface 115 extends from the protrusion 114 in one direction of the circumferential direction 107 (clockwise in FIG. 7). The first surface 115 is inclined with respect to the circumferential direction 107 so that the distance from the outer peripheral surface 112A of the inner ring 112 in the radial direction of the pulley 78 increases in the clockwise direction in FIG. One end of the first surface 115 is continuous with the protrusion 114 . The other end of first surface 115 is continuous with second surface 116 .

Second surface 116 extends generally along circumferential direction 107 . One end of the second surface 116 is continuous with the other end of the first surface 115 . The other end of the second surface 116 is continuous with the protrusion 114 .

The roller 113 is arranged between two adjacent protrusions 114 . That is, in this embodiment, the one-way clutch 83 has six rollers 113 . Note that the number of rollers 113 is not limited to six, and is determined according to the number of protrusions 114 .

The distance between the second surface 116 and the outer peripheral surface 112A of the inner ring 112 in the radial direction of the pulley 78 is larger than the diameter of the rollers 113 . The distance between the other end of the first surface 115 and the outer peripheral surface 112</b>A in the radial direction of the pulley 78 is larger than the diameter of the roller 113 . The distance between one end of the first surface 115 and the outer peripheral surface 112</b>A in the radial direction of the pulley 78 is smaller than the diameter of the roller 113 . As a result, when the roller 113 is positioned between the first surface 115 and the outer peripheral surface 112A in the radial direction of the pulley 78, the roller 113 is fixed in a state of being sandwiched between the first surface 115 and the outer peripheral surface 112A, and cannot move. becomes possible. On the other hand, the roller 113 is movable in the circumferential direction 107 when positioned between the second surface 116 and the outer peripheral surface 112A of the pulley 78 in the radial direction.

The inner ring 112 is tubular. Inside the inner ring 112, the shaft 62A of the discharge roller 62 is positioned. A gap 109 is formed between the inner ring 112 and the shaft 62A. A projection 117 (an example of a contact portion) is formed on the inner peripheral surface 112B of the inner ring 112 . The protrusion 117 protrudes radially inward of the pulley 78 , that is, toward the shaft 62</b>A located on the rotation center side of the pulley 78 . The protrusion 117 moves in the circumferential direction 107 in synchronization with the rotation of the inner ring 112 . The projection 117 enters the recess 118 of the shaft 62A through the gap 109. As shown in FIG.

Axle 62A includes recess 118 . The recess 118 is recessed from the outer peripheral surface 62B of the shaft 62A toward the radial center of the pulley 78 . The recess 118 is formed with a bottom surface 118A and two side surfaces 118B and 118C. The side surfaces 118B and 118C are surfaces that connect the bottom surface 118A and the outer peripheral surface 62B. The side surfaces 118B and 118C are spaced apart in the circumferential direction 107 and face each other. Protrusion 117 entering recess 118 is positioned between side surfaces 118B and 118C. The protrusion 117, the side surface 118B, and the side surface 118C are provided between the pulley 78 and the shaft 62A in the rotation transmission path of the carry motor 102. As shown in FIG. The side surface 118B is an example of a second surface. 118 C of side surfaces are an example of a 1st surface. The protrusion 117 and the recess 118 are examples of the idling portion.

The distance in the circumferential direction 107 between the side surfaces 118B and 118C is longer than the length in the circumferential direction 107 of the portion of the protrusion 117 that enters the recess 118 by a distance L1. That is, the protrusion 117 can move within the recess 118 by a maximum distance L1.

In the state shown in FIG. 7, when the shaft 62A of the ejection roller 62 rotates clockwise with the pulley 78 stopped (in other words, the ejection roller 62 rotates in the direction to transport the paper 12 in the transportation direction 16). When the amount of rotation of the shaft 62A reaches or exceeds a predetermined amount (the amount of rotation by which the side surface 118C moves the distance L1), the side surface 118C pushes the projection 117, causing the inner ring 112 of the pulley 78 to rotate. In other words, the idling part causes the discharge roller 62 rotating in the direction of transporting the paper 12 in the transporting direction 16 to idle with respect to the pulley 78 by the amount of rotation for moving the side face 118C by the distance L1.

When forward rotation of the conveying motor 102 is transmitted to the outer ring 111 via the belt 81, the outer ring 111 rotates clockwise as shown in FIG. As a result, the protrusion 114, the first surface 115, and the second surface 116 rotate clockwise as shown in FIG. As a result, the roller 113 is sandwiched between the first surface 115 and the outer peripheral surface 112A of the inner ring 112 . As a result, the inner ring 112 rotates integrally with the outer ring 111 via the rollers 113 . That is, the inner ring 112 rotates clockwise as shown in FIG. As a result, the projection 117 comes into contact with the side surface 118B of the recess 118 of the shaft 62A of the discharge roller 62 and pushes it. The shaft 62A rotates integrally with the outer ring 111 and the inner ring 112 in synchronization with the movement of the side surface 118B pushed by the projection 117. As shown in FIG. As described above, the one-way clutch 83 transmits the forward rotation of the conveying motor 102 transmitted to the pulley 78 to the shaft 62A of the discharge roller 62 to rotate the discharge roller 62 in conjunction with the rotation of the pulley 78. .

The distance in the circumferential direction 107 between the protrusion 117 and the side surface 118C when the protrusion 117 is in contact with the side surface 118B (the state shown in FIG. 7) is the distance L1 described above.

On the other hand, when the reverse rotation of the conveying motor 102 is transmitted to the outer ring 111 via the belt 81, the outer ring 111 rotates counterclockwise as shown in FIG. As a result, the protrusion 114 , the first surface 115 , and the second surface 116 rotate counterclockwise as shown in FIG. 7, and the protrusion 114 moves away from the roller 113 . As a result, as shown in FIG. 8, the roller 113 is positioned between the second surface 116 and the outer peripheral surface 112A of the inner ring 112, and becomes movable within the gap 110. As shown in FIG. As a result, the rotation of the outer ring 111 is no longer transmitted to the inner ring 112 and the shaft 62A of the discharge roller 62 . That is, even if the outer ring 111 rotates, the ejection roller 62 does not rotate. As described above, the one-way clutch 83 idles the pulley 78 with respect to the discharge roller 62 and does not rotate the discharge roller 62 when the reverse rotation of the transport motor 102 is transmitted.

When the paper 12 sandwiched between the transport roller pair 54 and the discharge roller pair 55 is transported in the transport direction 16 by forward rotation of the transport motor 102, the trailing edge of the paper 12 (the upstream end in the transport direction 16) is transported. It exits from the roller pair 54 . In other words, the state in which the paper 12 is pinched by the transport roller pair 54 is changed to the state in which it is not pinched. At this time, the force in the conveying direction 16 that momentarily acts on the paper 12 acts from the paper 12 to the discharge roller 62 . This force causes the ejection roller 62 and its shaft 62A to rotate clockwise as shown in FIG. 9, the recess 118 of the shaft 62A moves a distance L2 clockwise as shown in FIG.

In this embodiment, when setting the distance L1, the length of the protrusion 117 in the circumferential direction 107 and the distance of the side surfaces 118B and 118C in the circumferential direction 107 are set so that the distance L1 is longer than the distance L2. That is, the amount of rotation of the shaft 62A that moves the side surface 118C clockwise by a distance L1 shown in FIG. The amount of rotation of the shaft 62A that rotates clockwise shown in FIG. Note that the distance L2 is obtained by conveying the paper 12 sandwiched between the conveying roller pair 54 and the discharging roller pair 55 in the conveying direction 16 so that the rear end of the paper 12 (the upstream end in the conveying direction 16) is moved to the conveying roller pair 54. You can find out by doing an experiment to get it out of.

Because the distance L1 is greater than the distance L2, the rotation of the shaft 62A in the clockwise direction shown in FIG. That is, the force does not act on the pulley 78 (the inner ring 112 and the outer ring 111). Therefore, even if the discharge roller 62 rotates due to the force, the pulley 78 does not rotate. That is, the discharge roller 62 idles with respect to the pulley 78 . Therefore, the inner ring 112 maintains a rotatable state integrally with the outer ring 111 via the rollers 113 . That is, the one-way clutch 83 is maintained in a state in which drive transmission from the conveying roller 60 to the discharge roller 62 is possible. That is, since only one of the inner ring 112 and the outer ring 111 does not rotate, no phase difference occurs between the inner ring 112 and the outer ring 111 .

After that, when the forward rotation of the conveying motor 102 is transmitted from the conveying roller 60 to the outer ring 111 via the belt 81 and the outer ring 111 rotates, the inner ring 112 also rotates via the rollers 113 . When the protrusion 117 moves a distance L2 due to the rotation of the inner ring 112, the protrusion 117 pushes the side surface 118B. As a result, the discharge roller 62 also rotates.

[Controller 130]
As shown in FIG. 6, the controller 130 has a CPU 131 , ROM 132 , RAM 133 , EEPROM 134 and ASIC 135 , which are connected by an internal bus 137 . The ROM 132 stores programs and the like for the CPU 131 to control various operations. The RAM 133 is used as a storage area for temporarily recording data, signals, etc. used when the CPU 131 executes the above programs, or as a work area for data processing. The EEPROM 134 stores settings, flags, and the like that should be retained even after the power is turned off.

The conveying motor 102 and the carriage motor 103 are connected to the ASIC 135 . The ASIC 135 generates a drive signal for rotating each motor, and controls each motor based on this drive signal. Each motor rotates forward or backward according to a drive signal from the ASIC 135 . For example, the controller 130 controls driving of the conveying motor 102 to drive each roller. Further, the controller 130 controls driving of the carriage motor 103 to reciprocate the carriage 23 . The controller 130 also controls the recording head 39 to eject ink from the nozzles 40 .

A sensor 120 and a rotary encoder 121 are also connected to the ASIC 135 . The controller 130 detects the existence of the sheet 12 at the arrangement position of the sensor 120 based on the detection signal output from the sensor 120 . Also, the controller 130 detects the position of the paper 12 based on the detection signal output from the sensor 120 and the pulse signal output from the rotary encoder 121 .

[Image recording process]
Image recording processing in this embodiment will be described with reference to FIG. The image recording process is executed by the CPU 131 of the controller 130 . Note that each of the following processes may be executed by the CPU 131 reading out a program stored in the ROM 132 , or may be implemented by a hardware circuit mounted on the controller 130 .

The controller 130 executes image recording processing in response to receiving a recording instruction from the user to record an image on the paper 12 (two sheets of paper 12 in the example of FIG. 10). The acquisition destination of the recording instruction is not particularly limited. For example, the recording instruction may be acquired through the operation unit 17 (see FIG. 1) provided in the multifunction device 10, or may be acquired from an external device through a communication network. The controller 130 records an image on the paper 12 by controlling the operations of each roller, carriage 23, and recording head 39 according to the acquired recording instructions.

The controller 130 executes the feeding process of the sheet 12 (this sheet 12 is hereinafter referred to as the preceding sheet 12A (an example of the first sheet)) (S10). The feeding process of the preceding sheet 12A is a process of causing the leading edge (the downstream end in the conveying direction 16) of the preceding sheet 12A supported by the feeding tray 20 to reach the conveying roller pair 54. FIG. In step S<b>10 , the controller 130 rotates the feed roller 25 by rotating the transport motor 102 in reverse. When the conveying motor 102 reverses, the feeding roller 25 rotates in the direction to convey the preceding sheet 12A backward, and the conveying roller 60 reverses, but the discharge roller 62 does not rotate. When the leading edge of the preceding sheet 12A reaches the conveying roller pair 54 (S20: Yes), the preceding sheet 12A is skew-corrected by the conveying rollers 60 rotating in reverse.

Next, the controller 130 executes the recording process on the preceding sheet 12A (S30). The recording process on the preceding sheet 12A is a process of recording an image on the preceding sheet 12A. Specifically, in step S30, the controller 130 alternately and repeatedly executes the transport process and the ejection process. The transport process is a process of transporting the preceding sheet 12A that has reached the transport roller pair 54 by at least one of the transport roller pair 54 and the discharge roller pair 55 by a predetermined line feed width in the transport direction 16 . The ejection process is a process of ejecting ink from the recording head 39 onto the preceding paper 12A that has been conveyed by a predetermined line feed width.

In the transport process, the controller 130 rotates the transport motor 102 forward to rotate the rollers 60 and 62 forward. Note that the feed roller 25 does not rotate when the transport motor 102 rotates forward. In addition, in the ejection process, the controller 130 stops the transport motor 102 to stop the rollers 60 and 62, drives the carriage motor 103 to move the carriage 23 along the left-right direction 9, and at a predetermined timing. Ink is ejected from the recording head 39 .

When the controller 130 determines that the trailing edge of the preceding sheet 12A (upstream edge in the first conveying direction 16A) has reached the predetermined position (S40: Yes), the subsequent sheet 12B is fed (S50).

As shown in FIG. 11, the predetermined position is a state in which the preceding sheet 12A is nipped by the discharge roller pair 55 and not nipped by the transport roller pair 54, and the trailing edge P1 of the preceding sheet 12A and the transport roller It is a position where the distance along the conveying direction 16 from the sandwiching position P2 of the paper 12 by the pair 54 is the distance L3. The distance L3 will be described later.

The succeeding sheet 12B is a sheet positioned immediately below the preceding sheet 12A in the feed tray 20, and is a sheet fed to the conveying path 65 by the feed tray 20 after the preceding sheet 12A. The process of feeding the succeeding paper 12B is a process of causing the leading edge of the succeeding paper 12B supported by the feed tray 20 to reach the conveying roller pair 54 . In step S<b>50 , the controller 130 rotates the feed roller 25 by rotating the transport motor 102 in reverse. Since the discharge roller 62 does not rotate when the transport motor 102 is reversed, the preceding paper 12A is not transported and remains at a predetermined position. That is, while step S50 is being executed, the recording process on the preceding sheet 12A is interrupted.

When the succeeding sheet 12B reaches the conveying roller pair 54 and comes into contact with the conveying roller pair 54 (S60: Yes), the recording process on the preceding sheet 12A is resumed (S70).

When the feeding process (S50, S60) shifts to the conveying process (S70) in the recording process, the conveying motor 102 switches from reverse rotation to forward rotation.

Here, in this embodiment, the pulley 78 and the discharge roller 62 are provided with idling portions (the protrusion 117, the side surface 118B, and the side surface 118C). Therefore, when the transport motor 102 rotates forward, as shown in FIG. The projection 117 may become separated from the side surface 118B when the state changes from the clamped state to the non-clamped state, or when the transport motor 102 is switched from normal rotation to reverse rotation (see, for example, FIG. 9). .

9, the projection 117 moves by a distance L2 in FIG. The pulley 78 idles with respect to the discharge roller 62 only for this amount of time. In this case, while the transport roller 60 rotates forward to transport the succeeding paper 12B in the transport direction, the preceding paper 12A is stopped because the discharge roller 62 is stopped. As a result, the leading edge of the succeeding sheet 12B may catch up with the trailing edge of the preceding sheet 12A.

However, in this embodiment, the distance L3 (see FIG. 11) is such that the conveying roller pair 54 is rotated by a predetermined amount (the amount of rotation of the pulley 78 corresponding to the movement of the protrusion 117 by the distance L1). is set longer than the distance by which the succeeding paper 12B is conveyed.

Here, the distance L1 is the difference between the distance in the circumferential direction 107 between the side surfaces 118B and 118C and the length in the circumferential direction 107 of the portion of the protrusion 117 that is inserted into the recess 118 . That is, the amount by which the projection 117 moves the distance L1 is the maximum amount of idling of the pulley 78 with respect to the discharge roller 62 . Therefore, when the feeding process (S50, S60) shifts to the transporting process (S70) in the recording process, the projection 117 is located at any position between the side surfaces 118B and 118C. The leading edge of the succeeding sheet 12B does not catch up with the trailing edge of the preceding sheet 12A due to idle rotation.

When the recording process on the preceding sheet 12A is completed, the recording process on the succeeding sheet 12B is started (S80). In the conveying process in the recording process on the succeeding sheet 12B, the succeeding sheet 12B is conveyed in the conveying direction 16 by a predetermined line feed width, and the preceding sheet 12A is also conveyed in the conveying direction 16 by a predetermined line feed width. As a result, the preceding sheet 12A is ejected to the ejection tray 21. FIG.

When the recording process on the succeeding paper 12B is completed, the controller 130 executes the discharge process on the succeeding paper 12B (S90). The ejection process is a process of causing the ejection roller pair 55 to transport the succeeding paper 12B on which an image is recorded toward the ejection tray 21 in the transport direction 16 .

When the succeeding paper 12B is discharged to the discharge tray 21, a series of image recording processing is completed. In FIG. 10, an example in which an image is recorded on two sheets of paper 12 has been described. is repeated for the number of sheets 12 on which images are to be recorded. However, in steps S40 to S80, the preceding sheet 12A becomes the succeeding sheet 12B, and the succeeding sheet 12B becomes the sheet 12 to be fed from the feed tray 20 next.

[Effect of this embodiment]
According to the present embodiment, the trailing edge of the paper 12 is removed from the transport roller pair 54 by transporting the paper 12 in a state in which the paper 12 is sandwiched between the transport roller pair 54 and the discharge roller pair 55. At this time, a force in the transport direction 16 acting momentarily on the paper 12 acts from the paper 12 to the ejection roller 62 . This force momentarily rotates the discharge roller 62 . Here, the predetermined amount by which the idling portion (the projection 117 and the recess 118) can cause the discharge roller 62 to idle with respect to the pulley 78 is larger than the amount of rotation of the discharge roller 62 caused by instantaneous rotation. Therefore, the discharge roller 62 idles with respect to the pulley 78 . Therefore, since the inner ring 112 of the one-way clutch 83 does not rotate, the one-way clutch 83 is maintained in a state in which drive transmission from the conveying roller 60 to the discharge roller 62 is possible. In other words, no phase difference occurs between the inner ring 112 and the outer ring 111 of the one-way clutch 83 . After that, when the forward rotation of the conveying motor 102 is transmitted from the conveying roller 60 to the outer ring 111 of the one-way clutch 83 and the outer ring 111 rotates, the inner ring 112 of the one-way clutch 83 and the discharge roller 62 also rotate.

Further, according to the present embodiment, the function of the idling portion can be realized with a simple configuration of the protrusion 117 and the recess 118 .

In addition, according to the present embodiment, each part of the idling portion (the projection 117 and the recess 118) is concentrated near the discharge roller 62, so that the occupied space of the idling portion can be reduced.

In addition, since the discharge roller 62 is idly rotated by the idling portion by a predetermined amount, in order to rotate the discharge roller 62, it may be necessary to rotate the conveying motor 102 by an amount corresponding to the predetermined amount. However, in this case, the conveying roller 60 also rotates excessively by an amount corresponding to the predetermined amount.

According to the present embodiment, the transport direction 16 between the trailing edge P1 of the preceding sheet 12A and the nipping position P2 of the succeeding sheet 12B by the transport roller pair 54 while the leading edge of the succeeding sheet 12B is in contact with the transport roller pair 54 is longer than the distance that the subsequent paper 12B is transported by the transport roller pair 54 while the pulley 78 rotates a predetermined amount (the amount of rotation of the pulley 78 corresponding to the movement of the protrusion 117 by the distance L1). long. Therefore, in this state, even if the transport roller 60 rotates more than the discharge roller 62 by the rotation of the pulley 78 by a predetermined amount, the succeeding paper 12B can be prevented from colliding with the preceding paper 12A.

[Modification]
In the embodiment described above, as shown in FIG. 7, only one projection 117 was provided, but as shown in FIG. good. In this case, the plurality of protrusions 117 are provided at intervals along the circumferential direction 107 on the inner peripheral surface 112B of the inner ring 112 . Also, in this case, recesses 118 are provided corresponding to each of the plurality of protrusions 117 . That is, in this case, the recesses 118 are provided in the same number as the protrusions 117 . The interval between two adjacent projections 117 may be equal as shown in FIG. 12, or may be different unlike in FIG.

According to the embodiment shown in FIG. 12, the rigidity of the members (pulley 78 and shaft 62A) provided with projections 117 and recesses 118 can be increased.

In the above-described embodiment, the rollers 60 and 62 for conveying the paper 12 in the conveying direction 16 rotate forward, and the rollers 60 and 62 for conveying the paper 12 in the opposite direction to the conveying direction 16 rotate in reverse. there were. However, contrary to the above-described embodiment, the rollers 25, 60, and 62 for conveying the paper 12 in the direction opposite to the conveying direction 16 rotate normally, and the rollers 25, 60, and 62 for conveying the paper 12 in the conveying direction 16 rotate normally. The rollers 60, 62 may be reversing.

In the above-described embodiment, the transport roller 60 rotates forward when the forward rotation of the transport motor 102 is transmitted, and reversely rotates when the reverse rotation of the transport motor 102 is transmitted. However, contrary to the embodiment described above, the conveying roller 60 may rotate forward when the reverse rotation of the transport motor 102 is transmitted, and may rotate reversely when the forward rotation of the transport motor 102 is transmitted.

In the embodiment described above, the protrusion 117 is provided on the inner peripheral surface 112B of the inner ring 112, and the recess 118 is provided on the outer peripheral surface 62B of the shaft 62A of the discharge roller 62. FIG. However, contrary to the embodiment described above, the protrusion 117 may be provided on the outer peripheral surface 62B of the shaft 62A of the discharge roller 62 and the recess 118 may be provided on the inner peripheral surface 112B of the inner ring 112 .

In the embodiment described above, the idling portion was provided on the pulley 78 having the one-way clutch 83 . However, the idling portion may be provided at a position other than the above embodiment as long as it is between the pulley having the one-way clutch 83 and the discharge roller 62 in the transmission path of the rotation of the motor.

For example, one-way clutch 83 may be provided on pulley 77 (see FIG. 4). In this case, the pulley 77 is an example of a rotating body. That is, the rotating body does not necessarily need to rotate around the shaft 62A of the discharge roller 62. FIG. In this case, the idling portion provided in the pulley 78 is located at a different position from the pulley 77 having the one-way clutch 83, and the pulley 77 having the one-way clutch 83 and the discharge roller 62 in the transmission path of the rotation of the motor. is set between

Also, for example, the one-way clutch 83 is provided on the pulley 77 (see FIG. 4), and the pulleys 77 and 78 are connected not through the belt 81 (see FIG. 4) but through a plurality of gears. may In this case, if a backlash is formed between two adjacent gears in the plurality of gears, the backlash allows the discharge roller 62 to idle with respect to the pulley 77 . That is, in this case, the plurality of gears in which the backlash is formed can function as the idling portion. In this case, the total backlash formed by the plurality of gears is such that the paper 12 sandwiched between the transport roller pair 54 and the discharge roller pair 55 is transported in the transport direction 16 and exits the transport roller pair 54. The backlash between two adjacent gears in the plurality of gears is set so as to be greater than the amount of rotation of the discharge roller 62 rotated by the force acting from the paper 12 when the paper 12 is pressed.

10 MFP (image recording device)
12 Paper (sheet)
16 Conveying direction 54 Conveying roller pair (first roller pair)
55 Ejection roller pair (second roller pair)
60 Conveying roller (first roller)
62 Eject roller (second roller)
65... Conveying path 74... Transmission section (first transmission section)
78 pulley (rotating body)
83 One-way clutch 102 Conveying motor (motor)
117...Protrusion (idling part)
118 ... concave portion (idling portion)

Claims (6)

a forward and reverse motor;
It is positioned in the sheet conveying path, and rotates in a direction to convey the sheet in the conveying direction when one of the forward and reverse rotation of the motor is transmitted, and the other of the forward and reverse rotation of the motor is transmitted. a first roller pair having a first roller that rotates in a direction to convey the sheet in a direction opposite to the conveying direction;
a second roller pair having a second roller located downstream of the first roller in the transport path in the transport direction;
a first transmission unit capable of transmitting rotation of the motor from the first roller to the second roller;
The first transmission unit is
a rotating body having a one-way clutch that transmits one of the forward and reverse rotation of the motor to the second roller and does not transmit the other of the forward and reverse rotation of the motor to the second roller;
The second roller, which is provided between the rotating body and the second roller in the transmission path of the rotation of the motor and rotates in a direction for conveying the sheet in the conveying direction, is rotated by a predetermined amount with respect to the rotating body. and an idling part for idling,
The predetermined amount is rotated by a force acting from the sheet sandwiched between the first roller pair and the second roller pair when the sheet is conveyed in the conveying direction and passes through the first roller pair. a conveying device larger than the amount of rotation of the second roller. The idling part is
a first surface and a second surface spaced apart along the rotation direction of the rotating body and movable in the rotation direction;
a contact portion positioned between the first surface and the second surface and movable in the rotational direction;
the contact portion or one of the first surface and the second surface moves in synchronization with the rotation of the rotating body;
The second roller rotates in synchronization with one of the contact portion and the second surface being pushed by the other and moving,
2. The distance in the rotational direction between the contact portion and the first surface when the contact portion and the second surface are in contact with each other is a length corresponding to the predetermined amount. Conveyor. The rotating body is provided rotatably around the axis of the second roller,
The contact portion or one of the first surface and the second surface is provided on the inner peripheral surface of the rotating body,
3. The conveying device according to claim 2, wherein the contact portion or the other of the first surface and the second surface is provided on the shaft of the second roller. A plurality of the contact portions are provided at intervals in the rotation direction,
4. The conveying device according to claim 2, wherein the first surface and the second surface are provided corresponding to each of the plurality of contact portions. a tray for supporting sheets;
a feeding roller for feeding the sheet supported by the tray to the conveying path;
a second transmission unit that does not transmit one of the forward rotation and the reverse rotation of the motor to the feeding roller and transmits the other of the forward rotation and the reverse rotation of the motor to the feeding roller;
a sensor positioned upstream in the conveying direction of the first roller in the conveying path and detecting a sheet;
a controller;
The above controller is
rotating the motor in one of the forward and reverse directions to cause the first roller pair to convey the first sheet positioned on the conveying path in the conveying direction;
While the first sheet is sandwiched between the second roller pair, the motor is rotated in the other direction of forward rotation or reverse rotation to cause the feed roller to rotate the second sheet supported by the tray. feed it to the transport path,
an upstream end of the first sheet in the conveying direction and a position where the sheet is nipped by the first roller pair in a state where the downstream end of the second sheet in the conveying direction is in contact with the first roller pair; in the conveying direction is longer than the distance over which the second sheet is conveyed by the first roller pair while the rotating body rotates by the predetermined amount. transport device. a conveying device according to any one of claims 1 to 5;
an image recording device located between the first roller pair and the second roller pair in the conveying path and configured to record an image on a sheet.

Images