JP2024033755A - recording device - Google Patents

Abstract

To provide a technology that can prevent reverse rotation of a conveyance roller with a simple configuration without increasing a drive load when the conveyance roller rotates in a normal rotation direction.SOLUTION: A recording device includes: a first roller 28 that rotates in a normal rotation direction and conveys a sheet in a conveyance direction; a first gear that transmits drive to the first roller 28; a second gear that engages with the first gear; an idling part in which the second gear can idly rotate; and a locking part that locks the second gear so as to restrict rotation of the second gear when the first gear receives a force that rotates the first roller in a second direction opposite to a first direction in which the first roller rotates in the normal rotation direction.SELECTED DRAWING: Figure 8

Description

The present invention relates to an image recording apparatus, and more particularly to an image recording apparatus including a mechanism for restricting a conveyance roller from rotating in a direction opposite to a sheet conveyance direction.

2. Description of the Related Art Conventionally, there has been known a paper image recording apparatus that corrects skew feeding by bending the sheet between two rollers or by abutting the end of the sheet against one roller when conveying the sheet. At this time, the roller upstream in the conveyance direction receives a reaction force from the sheet, and a return force is generated that attempts to rotate the roller in the opposite direction to the conveyance direction. If the roller rotates in the opposite direction to the conveyance direction due to the return force, the deflection of the sheet may be resolved, or the sheet end may be released from the abutting state, which may result in insufficient sheet skew correction. There is. Therefore, as shown in Patent Document 1 and Patent Document 2, there are known devices that are provided with a mechanism for suppressing reverse rotation of the rollers.

JP2013-035688A Japanese Patent Application Publication No. 06-016261

However, Patent Documents 1 and 2 use biasing members such as springs and resistance members such as viscous grease. Therefore, when the transport roller rotates to transport the paper, it rotates while receiving the force of the biasing member and the resistance member, which increases the driving load when the transport roller rotates, resulting in an increase in the size of the drive motor and a reduction in the number of parts. There were issues such as increased power consumption and increased power consumption. Furthermore, since space is required to arrange springs and the like, there is a problem of increasing the size of the device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that can prevent a conveyance roller from rotating in reverse using a simple configuration without increasing the driving load during normal rotation of the conveyance roller.

In order to achieve the above object, the recording device of the present invention includes:
a first gear that transmits drive to the first roller;
a second gear meshing with the first gear;
an idling portion in which the second gear can idly rotate;
The first gear is configured to restrict rotation of the second gear when the first gear receives a force that causes the first roller to rotate in a second direction opposite to the first direction that causes the first roller to rotate in the normal rotation direction. a locking portion that locks the second gear;
It is characterized by having the following.

According to the present invention, with a simple configuration, reverse rotation of the conveyance roller can be prevented without increasing the driving load during forward rotation of the conveyance roller.

A perspective view showing an image recording device in this embodiment Block diagram of an image recording device in this embodiment A perspective view showing a conveyance section of an image recording apparatus in this embodiment A diagram showing the configuration of a one-way clutch in this embodiment A diagram showing the configuration of a one-way clutch in this embodiment Diagram showing the direction and route of drive transmission in this embodiment Diagram showing the direction and route of drive transmission in this embodiment A diagram showing the drive configuration of the transport unit in this embodiment Diagram showing the driving direction and the state of the second gear in this embodiment Diagram showing the driving direction and the state of the second gear in this embodiment Diagram showing the driving direction and the state of the second gear in this embodiment A diagram showing the arrangement of the second gear in this embodiment A sectional view showing the second gear receiving part in this embodiment A diagram showing the first registration operation of the image recording apparatus in this embodiment A diagram showing the second registration operation of the image recording apparatus in this embodiment

EMBODIMENT OF THE INVENTION Below, with reference to drawings, the form for implementing this invention is illustratively described in detail based on an Example. Note that the dimensions, materials, shapes, and relative arrangement of the components described in this embodiment should be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. Furthermore, not all combinations of features described in this embodiment are essential to the solution of the present invention. The components described in the embodiments are merely examples, and the scope of the present invention is not intended to be limited thereto.

(First embodiment)
FIG. 1 is a perspective view showing the internal configuration of a recording apparatus M according to a first embodiment of the present invention. The recording device M is a multifunction device that includes a print section and a scanner section (not shown) placed above the print section, and various processes related to image recording and reading operations are performed separately in the print section and the scanner section. Or they can be executed in conjunction.

The scanner unit is equipped with an ADF (Auto Document Feeder) and an FBS (Flatbed Scanner), and can read documents automatically fed by the ADF and scan documents placed on the document table of the FBS by the user. It can be performed. Note that although the recording apparatus according to this embodiment is a multifunction device that has both a print section and a scanner section, it may be of a form that does not include a scanner section.

The print section is generally composed of a first paper feed section 1, a second paper feed section 2, a conveyance section 3, a recording section 4, and a paper discharge section 8. A user loads sheets as recording media into the first paper feed section 1 and the second paper feed section 2. The transport unit 3 transports sheets fed from the first paper feed unit 1 or the second paper feed unit 2 along a predetermined sheet transport path with high precision. The recording unit 4 records an image on the sheet being conveyed by the conveyance unit 3. The recording unit 4 is, for example, a liquid ejection type recording unit that ejects ink as a recording liquid onto a sheet to record an image on the sheet. The sheet discharge unit 8 is loaded with sheets discharged after images have been recorded thereon. The paper ejecting section 8 includes a sheet stacking section 81 and an extension tray 82 that can be pulled out from the recording apparatus M in order to expand the stacking area when a large sheet is ejected. Furthermore, the maintenance section 5 performs maintenance on the recording section 4, and the maintenance section The drive unit 6 switches the drive to one of the drive units 5 and transmits the drive. All of these units are fastened to the base 7 to constitute a printing section.

Next, a series of steps for recording an image on a sheet of the recording apparatus M in this embodiment will be described. The sheet is fed to a conveyance section 3 by a paper feed section 2 (not shown). The sheet fed from the paper feed section 2 is moved by a pair of conveyance rollers, which are a conveyance roller 32 and a pinch roller 33 driven by the conveyance roller 32, to adjust the positions of the left and right leading ends in the width direction of the sheet with respect to the conveyance direction. It can be arranged.

The recording unit 4 includes a carriage 41 on which a recording head 42 is mounted, and a chassis 44 that supports the carriage 41. The carriage 41 can reciprocate in a scanning direction perpendicular to the conveying direction of the fed sheet. When the sheet conveyed by the pair of conveyance rollers passes over a platen that urges the sheet, which is provided at a position facing the recording unit 4, an image is recorded on the sheet by the recording head 42 while the carriage 41 is scanning. Ru.

Thereafter, an operation is performed to record an image on one side of the sheet, and the sheet with the image recorded thereon is discharged to the paper discharge section 8 through a pair of paper discharge rollers including a paper discharge roller 34 and a spur 35.

FIG. 2 is a block diagram of the recording apparatus M in this embodiment. Reference numeral 901 denotes an MPU that controls operations of various parts, data processing, and the like. 902 is a ROM that stores programs and data executed by the MPU 901. A RAM 903 temporarily stores processing data executed by the MPU 901 and data received from the host computer 906. The print head 42 is controlled by a print head driver 942. The carriage 41 is driven by a carriage motor 43. Carriage motor 43 is controlled by carriage motor driver 943. The conveyance roller 32 and the paper ejection roller 34 are driven by the conveyance motor 31. The transport motor 31 is controlled by a transport motor driver 931. The host computer 906 includes a printer driver 9061 for processing recording information such as a recorded image and image quality and communicating with the recording apparatus M when a user instructs execution of a recording operation. The MPU 901 exchanges recorded images and the like with a host computer 906 via an I/F unit 905.

FIG. 3 is a perspective view showing the conveyance section of the recording apparatus in this embodiment. The conveyance motor 31 as a single drive source is connected (drivingly connected) to the conveyance roller 32 by a drive train 26 . The conveyance roller 32 is capable of rotating in the direction of rotation in which the sheet P is conveyed in the conveyance direction (hereinafter referred to as normal rotation or normal rotation direction) and in the opposite direction (hereinafter referred to as reverse rotation or reverse rotation direction) depending on the rotation direction of the conveyance motor 31. It is. The intermediate roller 28 is connected (drivingly connected) to the conveyance roller 32 via a drive train 27 . A one-way rotation mechanism, which will be described later, is arranged in the middle of the drive train 27 and is configured by a combination of a one-way clutch 72 and a one-way clutch 73. The rotation input from the intermediate input gear 61 is transmitted through the one-way rotation mechanism to the intermediate roller input gear 66 only in the rotation direction shown in FIG. 3, regardless of the rotation direction of the intermediate input gear 61. is possible. The intermediate roller 28 rotates in the rotation direction shown in FIG. 3 (hereinafter referred to as normal rotation) in which the sheet P is conveyed in the conveying direction when the intermediate roller input gear 66 receives an input in the direction shown in the figure.

In other words, the intermediate roller 28 as the first roller and the conveyance roller 32 as the second roller can be respectively driven by the driving force of the conveyance motor 31 which is a common drive source. Further, with the above configuration, by switching the rotation direction of the conveyance motor 31, a state in which the intermediate roller 28 is rotated in the forward direction while the conveyance roller 32 is rotated in the normal direction, and a state in which the intermediate roller 28 is rotated in the forward direction while the conveyance roller 32 is rotated in the reverse direction. It is possible to switch.

FIGS. 4(a) to 5(b) are diagrams showing the configuration of a one-way clutch used in the one-way rotation mechanism in this embodiment. 4(a) is an exploded perspective view of the one-way clutch 72, and FIG. 4(b) is an assembled perspective view of the one-way clutch 72 when each member is assembled according to the arrows in FIG. 4(a). 5(a) is an exploded perspective view of the one-way clutch 73, and FIG. 5(b) is an assembled perspective view of the one-way clutch 73 when each member is assembled according to the arrows in FIG. 5(a). Note that in each clutch, there may be only one planetary gear, or there may be a plurality of three or more planetary gears.

As shown in FIGS. 4A and 4B, the one-way clutch 72 includes a first input gear 62, a first output gear 63, and a planetary gear 67. The first input gear 62 has a receiving portion (holding portion) 62c that receives (holds) the planetary gear 67. The receiving portion 62c includes an idling portion 62a and a locking portion 62b. The idle portion 62a is a recess provided so as to be recessed radially inward. The planetary gear 67 is held by slidingly contacting the idling portion 62a, allowing the planetary gear 67 to idly rotate. The locking portion 62b has an edge that engages with the teeth of the planetary gear 67 to suppress rotation of the planetary gear 67. Further, the first output gear 63 meshes with a first spur gear portion 63a (hereinafter referred to as the first gear portion 63a), a second spur gear portion 63b (hereinafter referred to as the second gear portion 63b), and a planetary gear 67. It has an internal gear 63c. With the above configuration, the one-way clutch 72 transmits the rotation in the solid line direction in FIG. 4(b) input to the first input gear 62 to the first output gear 63, while the rotation in the dotted line direction in FIG. 4(b) is input to the first input gear 62, the drive is not transmitted to the first output gear 63.

As shown in FIGS. 5A and 5B, the one-way clutch 73 includes a second input gear 64, a second output gear 65, and a planetary gear 68. Similar to the one-way clutch 72, the one-way clutch 73 also transmits the rotation input to the second input gear 64 in the direction shown by the solid line in FIG. 5(b) to the second output gear 65, while When the rotation in the direction is input to the second input gear 64, the drive to the second output gear 65 is not transmitted.

The one-way clutch 72 and one-way clutch 73 used in this embodiment are not limited to the above configuration, and may be any mechanism that transmits drive in only one direction, such as a spring clutch or a ratchet.

6 and 7 are diagrams illustrating the gear rotation direction and the drive transmission path in this embodiment. A one-way rotation mechanism that combines one-way clutch 72 and one-way clutch 73 will be described. The first input gear 62 of the one-way clutch 72 meshes with the intermediate input gear 61 and the second input gear 64 of the one-way clutch 73. The intermediate roller input gear 66 meshes with the first output gear 63 of the one-way clutch 72 and the second output gear 65 of the one-way clutch 73.

FIG. 6 is a diagram showing a drive transmission path when the conveyance roller 32 is rotating normally (second conveyance state). When the conveyance roller 32 is rotating normally, the intermediate input gear 61 rotates clockwise. In response to the clockwise rotation of the intermediate input gear 61, the first input gear 62 of the one-way clutch 72 rotates counterclockwise, and the second input gear 64 of the one-way clutch 73 rotates clockwise. At this time, in the one-way clutch 73, the clockwise rotation input to the second input gear 64 is transmitted to the second output gear 65. When the second output gear 65 rotates clockwise, the intermediate roller input gear 66 rotates counterclockwise, causing the intermediate roller 28 to rotate normally. Therefore, when the transport roller 32 rotates normally, the intermediate roller 28 rotates normally, and the sheet P can be transported in the transport direction. Further, at this time, the first output gear 63 rotates clockwise due to the counterclockwise rotation of the intermediate roller input gear 66, but the first input gear 62 is rotating counterclockwise, and the first input gear 62 rotates counterclockwise. Since the drive of the first output gear 63 and the first output gear 63 are cut off, the first output gear 63 can rotate in different rotational directions.

As shown in FIG. 7, when the conveyance roller 32 is reversed (first conveyance state), the intermediate input gear 61 rotates counterclockwise. In response to the counterclockwise rotation of the intermediate input gear 61, the first input gear 62 of the one-way clutch 72 rotates clockwise, and the second input gear 64 of the one-way clutch 73 rotates counterclockwise. . At this time, in the one-way clutch 72, the clockwise rotation input to the first input gear 62 is transmitted to the first output gear 63. When the first output gear 63 rotates clockwise, the intermediate roller input gear 66 rotates counterclockwise, causing the intermediate roller 28 to rotate normally. Therefore, even when the conveyance roller 32 is reversely rotated, the intermediate roller 28 rotates normally, and the sheet P can be conveyed in the conveyance direction. Further, at this time, the second output gear 65 rotates clockwise due to the counterclockwise rotation of the intermediate roller input gear 66, but the second input gear 64 is rotating counterclockwise, and the second input gear 64 rotates counterclockwise. Since the drive of the second output gear 65 is cut off, the second output gear 65 can rotate in different rotational directions.

With the above configuration, it is possible to realize a mechanism in which the intermediate roller 28 rotates in the normal direction regardless of the rotation direction of the conveyance roller 32.

FIG. 8 is a diagram showing the drive configuration of the transport section in this embodiment. The regulation gear 69 (second gear) is arranged in a receiving part (holding part) 71c provided on the base member 71. The one-way clutch 72 is fitted into a shaft portion 71e provided on the base member 71, and a first gear portion 63a (first gear portion) provided on the first output gear 63 (first gear) is connected to the regulating gear 69 ( 2nd gear). Further, the first output gear 63 is connected (drivingly connected) to the intermediate roller 28 (first conveyance roller) via an intermediate roller input gear 66.

9 to 11 are diagrams showing the driving direction and the state of the second gear in this embodiment. A state in which the rotational direction of the first output gear 63 (first gear) is restricted depending on the state of the restriction gear 69 (second gear) will be described.

When the first output gear 63 rotates in the rotation direction A (first direction) shown in FIG. 9, the intermediate roller 28 rotates in the paper conveyance direction. At this time, the tooth tips of the regulation gear 69 come into sliding contact with the idling portion 71a, so that the regulation gear 69 is held so as to rotate about the rotation center 1 and rotates in the A' direction. Further, since the locking portion 71b is provided outside the tip circle of the regulation gear 69, when the regulation gear 69 rotates at the rotation center 1, it does not interfere with the rotation.

As shown in FIG. 9, the radius r1 of the pitch circle of the first gear part 63a, the radius r2 of the pitch circle of the regulation gear 69, the radius r3 of the tip circle of the regulation gear 69, the pitch circle of the first gear part 63a, and the regulation Let CL be the clearance provided between the pitch circles of the gear 69. By providing this clearance CL, backlash can be set between the first gear portion 63a and the regulation gear 69. It is preferable that the rotation center 1 is located on a circle having a radius of r1+r2+CL from the rotation center 3, and the circular arc of the idling portion 71a is arranged to coincide with the circular arc of the radius r3 from the rotation center 1. With the above configuration, the first gear part 63a and the regulating gear 69 rotate while maintaining backlash appropriately between their axes, so that the driving load caused by the regulating gear 69 can be reduced.

Furthermore, if the center angle θ1 of the circular arc of the idling portion 71a is too large, it may catch on the tips of the teeth of the regulating gear 69 and prevent rotation in the A' direction. Furthermore, the sliding resistance of the regulating gear 69 also increases. On the other hand, if it is too small, it will fit between adjacent teeth of the regulation gear 69, making it impossible to maintain the position of the regulation gear 69. Therefore, the angle θ1 is preferably set to be equal to or greater than Z1/360 and equal to or less than 90° (Z1 is the number of teeth of the regulation gear 69).

When the intermediate roller 28 rotates in the reverse direction due to the generation of some load, the first output gear 63 rotates in the rotation direction B (second direction) shown in FIG. At this time, the rotation center (rotation axis) of the regulation gear 69 moves from rotation center 1 to rotation center 2. When the rotation center of the regulation gear 69 moves to the rotation center 2, the locking portion 71b enters within the tip circle diameter of the restriction gear 69, so the restriction gear 69 is locked with the locking portion 71b and rotates in the B' direction. is prevented. Therefore, the intermediate roller 28 is prevented from rotating in the reverse direction.

That is, the receiving part (holding part) 71c holds the regulating gear 69 (second gear) so that the rotational direction of the regulating gear 69 (second gear) can be regulated so as to allow rotation in only one direction. The regulation gear 69 is held in the receiving part 71c so as to be displaceable around the rotational axis of the first output gear 63 (first gear). The rotation can be regulated and held by the portion 71b. That is, the regulation gear 69 is a gear that is not supported in the present device, and whose rotational axis does not lie on one line.

A straight line (imaginary line segment) connecting the rotation center 3, which is the rotation center of the first output gear 63, and the rotation center 2 of the regulation gear 69, and a straight line (imaginary line) extending from the rotation center 2 and passing through the locking part 71b. Let the angle θ4 consist of . By setting the angle θ4 to 90° or more, the reaction force generated in the regulating gear 69 when the regulating gear 69 is locked is generated toward the rotation center 3, so that the regulating gear 69 can be locked with a stronger force.

As shown in FIG. 11, the locking portion 71b includes an edge portion 71b1, a first flat portion 71b2 continuous with the edge portion 71b1, and a second flat portion 71b2 continuous with the edge portion 71b1 on the opposite side of the first flat portion 71b2. It has a portion 71b3. The locking portion 71b is arranged such that the first flat portion 71b2 and the second flat portion 71b3 are continuous to form an angle θ2 via the edge portion 71b1 when viewed in the direction of the rotational axis of the first output gear 63. It becomes. The relationship between the angle θ2 of the locking portion 71b and the angle θ3 formed by tangents passing through the contact points of the tips of adjacent teeth of the regulating gear 69 with the locking portion 71b is preferably θ2≦θ3. With the above configuration, when preventing the intermediate roller 28 from rotating backward, the regulation gear 69 can easily be locked to the locking portion 71b.

FIG. 12 is a diagram showing the arrangement of the second gear in this embodiment. As shown in FIG. 12, when viewed in the direction of the rotational axis of the first output gear 63, an intermediate roller input gear 66 (third gear) that meshes with the first output gear 63 downstream of the first output gear 63 in the drive train. is arranged so that its height in the Z direction (position in the vertical direction) is higher than that of the first output gear 63 . Further, the regulation gear 69 is a gear smaller than the first output gear 63, and is substantially opposite to the intermediate roller input gear 66 when viewed in the rotational axis direction, and its height in the Z direction is approximately the same as that of the intermediate roller input gear 66. It is arranged at a position lower than the rotation center of the first output gear 63.

When the regulating gear 69 is locked to the locking portion 71b, the rotational moment of the first gear portion 63a tends to move the first gear portion 63a in the direction of arrow C with the locking portion 71b as the center of rotation. It is converted into the power to do. The regulating gear 69 is located on the negative side in the Y direction (upstream in the reverse direction) from the straight line 2, which is an imaginary line passing through the center of the first gear portion 63a (first output gear 63) and the center of the intermediate roller input gear 66. It is recommended to place According to the above configuration, the force that the first gear portion 63a receives is generated in a direction that does not change the distance between the shafts and the intermediate roller input gear 66, or in a direction that reduces the distance between the shafts. Thereby, it is possible to prevent an increase in backlash caused by widening the distance between the axes of the first output gear 63 and the intermediate roller input gear 66, and it is possible to reduce the amount of reverse rotation of the conveyance roller 32 until the regulation gear 69 is locked.

In addition, the regulation gear 69 is positioned above straight line 1, which is a tangent at the lower end (lowest end) in the Z direction of the tip circle of the first gear portion 63a, thereby increasing the device size in the Z direction. The regulation gear 69 can be arranged without any trouble.

Furthermore, it is better to arrange the locking portion 71b below the rotation center of the regulation gear 69 in the Z direction. When the regulating gear 69 moves from the rotation center 1 when idling to the rotation center 2 when locked, the regulating gear 69 moves easily due to its own weight, so the regulating gear 69 is locked when stopped. The amount of reversal of the transport roller can be reduced.

FIG. 13 is a sectional view of the space in which the regulation gear 69 is received. FIG. 13 is a diagram of the cross section indicated by the solid line in FIG. 12, viewed from the upstream side in the Y direction. The regulation gear 69 has a sliding surface 69a that slides on the first input gear 62 and a sliding surface 69b that slides on the base member 71. The regulation gear 69 is received between the base member 71 and the first input gear 62, and is freely movable in the X direction. When the regulation gear 69 is tilted (the state of the regulation gear 69' shown in FIG. 13), the sliding surface 69a touches the first input gear 62 before the tooth tip of the regulation gear 69 hits the tooth bottom 63e of the first gear. It is designed to correspond to Thereby, it is possible to prevent an increase in the driving load of the regulation gear 69 due to the regulation gear 69 being tilted and being pinched between the idling portion 71a and the tooth bottom portion 63e of the first output gear 63.

FIGS. 14(a) to 14(d) are diagrams showing the first registration operation of the image recording apparatus in this embodiment. As shown in FIG. 14(a), the sheet P fed by the paper feed roller 25 provided in the paper feed section 2 is transferred to the intermediate roller 28 and the driven roller 29 which comes into contact with the intermediate roller 28 under an urging force. It is conveyed in the conveying direction by the rotation of a roller pair consisting of and. At this time, the drive transmission path is as shown in FIG. 7, with the conveyance roller 32 (second roller) rotating in the reverse direction and the intermediate roller 28 (first roller) rotating in the normal direction. When the conveyance of the sheet P progresses and the leading edge of the sheet P reaches the conveying roller 32, since the conveying roller 32 is reversely rotated, the leading edge of the sheet P cannot advance further downstream in the conveying direction than the conveying roller 32, and the leading edge of the sheet P reaches the conveying roller 32. 32 and pinch roller 33 are stopped. On the other hand, since the intermediate roller 28 tries to convey the sheet P in the conveying direction, the sheet P forms a loop as shown in FIG. 14(b). Thereby, even if the timing of the left and right leading ends of the sheet P reaching the conveyance roller 32 is different, the positions of the left and right leading ends can be aligned.

After forming a loop and aligning the positions of the left and right leading ends of the sheet P, the rotation direction of the conveying roller 32 is changed as shown in FIG. 14(c). Since the drive transmission path changes from FIG. 7 to FIG. 6, the drive to the intermediate roller 28 is once disconnected, and the drive is reconnected after consuming backlash of the drive train, transmission delay of the one-way clutch, etc. .

However, when a loop is formed, a force that tries to eliminate the loop acts on the sheet P, so that the intermediate roller 28 receives a force from the sheet P in a direction that causes it to be reversed. At this time, if the intermediate roller 28 reverses, the loop will be eliminated, causing a problem that the left and right ends, which have been aligned once, will be shifted again. Therefore, during conveyance after aligning the left and right leading ends of the sheet P, it is important to prevent the intermediate roller 28 from reversing and to maintain the loop until conveyance by the conveyance roller 32 is started.

In this embodiment, when the intermediate roller 28 is about to reverse, the regulation gear 69 engages with the locking portion 71b to prevent the intermediate roller 28 from reversing, as shown in FIG. Thereby, even when the drive to the intermediate roller 28 is cut off, the loop of the sheet P can be maintained.

As shown in FIG. 14(d), when the conveyance roller 32 starts conveying the sheet P and the drive to the intermediate roller 28 is connected again, the regulation gear 69 slides against the idling portion 71a as shown in FIG. The rotation of the intermediate roller 28 is no longer inhibited. Furthermore, by making the roller circumferential speed of the conveying roller 32 faster than the roller circumferential speed of the intermediate roller 28, the deflection of the sheet is naturally resolved as the sheet is conveyed, and the reaction force caused by the deflection becomes an obstacle to sheet conveyance. This can be suppressed.

With the above configuration, it is possible to prevent the intermediate roller 28 from reversing due to the reaction force generated when registering the sheet P without using a biasing means such as a spring.

FIGS. 15(a) to 15(d) are diagrams showing the second registration operation of the printing apparatus in this embodiment. Note that this registering operation is a conveyance operation in which the conveyance roller 32 is instantaneously (temporarily) reversed by utilizing the period in which the drive to the intermediate roller 28 is cut off when the rotation direction of the conveyance roller 32 is switched. be. That is, after the rotation direction of the conveyance roller 32 is switched from normal rotation to reverse rotation, the intermediate roller 28, which has been in the drive disconnected state, consumes the backlash of the drive train, the transmission delay of the one-way clutch, etc., and the drive is reconnected. Before this, the rotation direction of the conveyance roller 32 is switched from reverse rotation to normal rotation.

As shown in FIG. 15A, the sheet P is conveyed in the conveyance direction by the rotation of a pair of rollers including an intermediate roller 28 and a driven roller 29 provided with an urging force. After the leading edge of the sheet P moves a certain amount downstream of the conveyance roller 32 in the conveyance direction, the rotation direction of the conveyance roller 32 is changed to reverse, and conveyance of the sheet P to the upstream side in the conveyance direction is started. At this time, the intermediate roller 28 is prevented from being reversed by being locked by the regulating gear 69 and the locking portion 71b. The portion of the sheet P that is sandwiched between the intermediate roller 28 and the driven roller 29 is held without being reversed, and the leading end portion is conveyed upstream in the conveyance direction by the reverse rotation of the conveyance roller 32. Therefore, the sheet P forms a loop between the conveyance roller 32 and the intermediate roller 28, as shown in FIG. 15(b). Thereby, the positions of the left and right leading ends of the sheet P can be aligned. Further, after the leading edge of the sheet P is transported a certain amount downstream in the transport direction from the transport roller 32, the transport roller 32 is reversed to form a loop, thereby reducing damage to the leading edge of the paper and adjusting the loop amount. There are advantages such as

After aligning the positions of the left and right leading ends of the sheet P by the loop, the conveyance direction of the conveyance roller 32 is changed to normal rotation again, as shown in FIG. 15(c), and conveyance of the sheet P is resumed. At this time, although the drive to the intermediate roller 28 remains cut off, the regulation gear 69 is in a state of being locked with the locking portion 71b, so that the loop can be maintained. As shown in FIG. 15(d), when the conveyance roller 32 starts conveying the sheet P and the drive to the intermediate roller 28 is connected again, the regulation gear 69 comes into sliding contact with the idling portion 71a, and the intermediate roller 28 rotates. It no longer inhibits

With the above configuration, even if the driving direction of the conveyance roller 32 is switched a plurality of times during loop formation, it is possible to continuously maintain a state in which the intermediate roller 28 is prevented from reversing.

The disclosure of the embodiment of the present invention includes the following configurations.
(Configuration 1)
a first roller that rotates in the normal rotation direction and transports the sheet in the transport direction;
a first gear that transmits drive to the first roller;
a second gear meshing with the first gear;
an idling portion in which the second gear can idly rotate;
The first gear is configured to restrict rotation of the second gear when the first gear receives a force that causes the first roller to rotate in a second direction opposite to the first direction that causes the first roller to rotate in the normal rotation direction. a locking portion that locks the second gear;
A recording device comprising:
(Configuration 2)
The recording device according to configuration 1, wherein the locking portion is provided downstream in the second direction with respect to the idling portion.
(Configuration 3)
Configuration 1 or 2, wherein the second gear is locked to the locking portion by a force received from the first gear when the first gear rotates in the second direction. The recording device described in .
(Configuration 4)
The configuration according to any one of configurations 1 to 3, wherein the second gear rotates in the idling portion by a force received from the first gear when the first gear rotates in the first direction. The recording device described in .
(Configuration 5)
The record according to any one of configurations 1 to 4, wherein the second gear is held by the holding portion so that its rotation center can be displaced around the rotation axis of the first gear. Device. (Configuration 6)
a third gear that meshes with the first gear on the downstream side of the first gear in a drive train that transmits drive to the first roller;
When viewed in the direction of the rotational axis of the first gear, the second gear has a rotational axis in the second direction with respect to an imaginary line passing through the rotational center of the third gear and the rotational center of the first gear. 6. The recording device according to any one of configurations 1 to 5, characterized in that the recording device is disposed on the upstream side.
(Configuration 7)
The second gear is arranged such that its position in the vertical direction is below the rotation axis of the first gear and above the lowest end of a gear portion of the first gear with which the second gear meshes. 7. The recording device according to any one of configurations 1 to 6, characterized in that:
(Configuration 8)
8. The recording device according to any one of configurations 1 to 7, wherein the locking portion is arranged such that the position in the vertical direction is below the rotation center of the second gear. .
(Configuration 9)
9. The recording apparatus according to any one of configurations 1 to 8, wherein the second gear is smaller than the first gear.
(Configuration 10)
10. The recording device according to any one of configurations 1 to 9, wherein the second gear is a gear that is not supported.
(Configuration 11)
a second roller provided downstream of the first roller in the sheet conveyance path;
Any one of configurations 1 to 10, wherein the circumferential speed of the second roller when rotating in the forward rotation direction is faster than the circumferential speed when the first roller rotates in the normal rotation direction. The recording device described in the configuration of.
(Configuration 12)
a recording section that records images on a sheet;
a conveyance unit that conveys the sheet;
A recording device comprising:
The transport section is
the first roller and the second roller, which are arranged upstream of the recording section in the sheet conveyance path;
A driving source,
a drive train that includes the first gear and transmits the driving force of the drive source to each of the first roller and the second roller;
Equipped with
a first conveyance state in which the first roller is rotated in the normal rotation direction and the second roller is rotated in a reverse rotation direction opposite to the normal rotation direction;
a second conveyance state in which the first roller and the second roller are rotated in the normal rotation direction;
12. The recording device according to configuration 11, wherein the recording device is configured to take the following configuration.
(Configuration 13)
The first gear is
a first gear portion with which the second gear meshes;
a second gear portion in which gears included in the drive train mesh;
13. The recording device according to configuration 12, comprising:
(Configuration 14)
14. The recording apparatus according to configuration 12 or 13, wherein the drive source is a single motor.
(Configuration 15)
After switching the rotation direction of the first roller from the normal rotation direction to the reverse rotation direction, and before the second roller starts rotating in the normal rotation direction from the drive disconnected state, the rotation direction of the first roller is changed. The recording device according to any one of configurations 12 to 14, characterized in that the reverse rotation direction is switched to the forward rotation direction.

28... Intermediate roller (first roller), 31... Conveyance motor, 32... Conveyance roller (second roller), 71... Drive base, 71a... Idle part, 71b... Locking part, 71c... Receiving part (holding part), 63...First output gear (first gear), 69...Regulation gear (second gear), P...Recording medium (sheet)

Claims (15)

a first roller that rotates in the normal rotation direction and transports the sheet in the transport direction;
a first gear that transmits drive to the first roller;
a second gear that meshes with the first gear;
an idle part in which the second gear can idle;
The first gear is configured to restrict rotation of the second gear when the first gear receives a force that causes the first roller to rotate in a second direction opposite to the first direction that causes the first roller to rotate in the normal rotation direction. a locking part that locks the second gear;
A recording device comprising: The recording device according to claim 1, wherein the locking portion is provided on the downstream side in the second direction with respect to the idling portion. 3. The second gear is locked to the locking portion by a force received from the first gear when the first gear rotates in the second direction. Recording device as described. 2. The recording apparatus according to claim 1, wherein the second gear rotates in the idling portion due to a force received from the first gear when the first gear rotates in the first direction. 2. The recording device according to claim 1, wherein the second gear is held so that its rotation center can be displaced around the rotation axis of the first gear. a third gear that meshes with the first gear on the downstream side of the first gear in a drive train that transmits drive to the first roller;
When viewed in the direction of the rotational axis of the first gear, the second gear has a rotational axis in the second direction with respect to an imaginary line passing through the rotational center of the third gear and the rotational center of the first gear. The recording device according to claim 1, wherein the recording device is arranged on the upstream side. The second gear is arranged such that its position in the vertical direction is below the rotation axis of the first gear and above the lowest end of a gear portion of the first gear with which the second gear meshes. The recording device according to claim 6, characterized in that: 8. The recording device according to claim 7, wherein the locking portion is arranged so that a position in the vertical direction is below a rotation center of the second gear. The recording apparatus according to claim 1, wherein the second gear is smaller than the first gear. The recording device according to claim 1, wherein the second gear is a gear that is not supported. a second roller provided downstream of the first roller in the sheet conveyance path;
The recording device according to claim 1, wherein a circumferential speed of the second roller when rotating in the forward rotation direction is faster than a circumferential speed when the first roller rotates in the normal rotation direction. . a recording section that records images on a sheet;
a conveyance unit that conveys the sheet;
A recording device comprising:
The transport section is
the first roller and the second roller, which are arranged upstream of the recording section in the sheet conveyance path;
A driving source,
a drive train that includes the first gear and transmits the driving force of the drive source to each of the first roller and the second roller;
Equipped with
a first conveying state in which the first roller is rotated in the normal rotation direction and the second roller is rotated in a reverse rotation direction opposite to the normal rotation direction;
a second conveyance state in which the first roller and the second roller are rotated in the normal rotation direction;
12. The recording device according to claim 11, wherein the recording device is configured to be able to take the following steps. The first gear is
a first gear portion with which the second gear meshes;
a second gear portion in which gears included in the drive train mesh;
13. The recording device according to claim 12, comprising: 13. The recording apparatus according to claim 12, wherein the drive source is a single motor. After switching the rotational direction of the first roller from the normal rotation direction to the reverse rotation direction and before the second roller starts rotating in the normal rotation direction from the drive disconnected state, the rotation direction of the first roller is changed. 13. The recording apparatus according to claim 12, wherein the reverse rotation direction is switched to the normal rotation direction.

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