Conveyance device and recording device

Abstract

To provide a conveyance device conveying recording media, and suppressed in movement of a conveying roller in a rotation axial direction when driving the conveying roller.SOLUTION: A conveyance device comprises: a conveying roller 51 conveying recording media; a first helical gear 372 rotating integrally with the conveying roller 51; a gear unit meshed with the first helical gear 372 and generating a thrust force to the conveyance roller 51; regulation means 378 regulating movement of the conveyance roller 51 in a rotation axial direction; and pressing means 376 pressing the conveyance roller 51 to the regulation means 378 in a pressing direction. The movement of the conveyance roller 51 by a resultant force in the rotation axial direction including a pressing force pressing the conveyance roller 51 by the pressing means 376 and the thrust force, is regulated by the regulation means 378, irrespective of a rotation direction of the conveyance roller 51.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a conveying device that is provided in a recording apparatus that performs a recording operation by nipping and conveying a recording medium with a conveying means. [Background technology]

[0002] In a recording device such as an inkjet printer, a recording medium is generally transported by a transport device having a transport roller and multiple gears. In such a transport device, a configuration using a helical gear is known to reduce operating noise caused by the striking sound of the gears.

[0003] Patent Document 1 discloses a configuration for a conveying device provided in a recording device, in which a conveying roller for conveying a recording medium is driven by a plurality of helical gears. In the above configuration, the thrust force generated by the helical gear in the direction of the rotation axis of the conveying roller is utilized to prevent rattling of the conveying roller in the direction of the rotation axis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-278495 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned configuration, when the rotation direction of the conveying roller is switched, the direction of the thrust force by the helical gear is reversed, and the conveying roller may move in the direction of the rotation axis. The movement of the conveying roller in the direction of the rotation axis moves the paper being conveyed by the conveying roller in the direction of the rotation axis, resulting in a decrease in print quality.

[0006] SUMMARY OF THE PRESENT DISCLOSURE The present invention relates to a transport device that transports a recording medium, and has an object to suppress movement of the transport roller in the direction of the rotation axis when the transport roller is driven. [Means for solving the problem]

[0007] In order to achieve the above object, the conveying device of the present invention comprises: A conveying roller for conveying the recording medium; A first helical gear that rotates integrally with the conveying roller; a gear unit that meshes with the first helical gear and generates a thrust force on the conveying roller; a restricting means for restricting movement of the conveying roller in the direction of the rotation axis; a pressing means for pressing the conveying roller in a pressing direction against the regulating means; Equipped with The movement of the conveying roller caused by a resultant force in the direction of the rotation axis, including the thrust force and the pressing force applied by the pressing means against the conveying roller, is regulated by the regulating means regardless of the rotation direction of the conveying roller. Effect of the Invention

[0008] According to the present invention, in a transport device that transports a recording medium, an object of the present invention is to suppress movement of a transport roller in the direction of a rotation axis when the transport roller is driven. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a perspective view showing the internal configuration of a recording apparatus in the first embodiment. [Diagram 2] FIG. 2 is a perspective view of a conveying section according to the first embodiment. [Diagram 3] FIG. 4 is a top view showing a gear train of the conveying section according to the first embodiment. [Figure 4] FIG. 3 is a cross-sectional view showing a movement restriction mechanism for a conveyor roller according to the first embodiment. [Diagram 5] FIG. 4 is a top view showing a state of the conveying roller according to the first embodiment during forward rotation. [Figure 6] FIG. 4 is a top view showing a state in which the conveying roller according to the first embodiment rotates in reverse. [Figure 7]FIG. 11 is a top view showing a helical output gear according to a second embodiment. [Figure 8] FIG. 11 is a top view showing a state of the conveying roller according to the second embodiment during forward rotation. [Figure 9] FIG. 11 is a top view showing a state in which the conveying roller according to the second embodiment rotates in reverse. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, with reference to the drawings, the embodiment for carrying out the present invention will be described in detail by way of example. The dimensions, materials, shapes, and relative arrangements of the components described in the embodiment should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not limited to the following embodiment. In addition, although multiple features are described in each of the following embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numbers are given to the same or similar configurations, and duplicated explanations may be omitted.

[0011] In the following explanation, "recording" (sometimes called "printing") broadly refers to the formation of images, patterns, etc. on a recording medium, or the processing of the medium. In other words, "recording" does not only refer to the formation of meaningful information such as characters and figures, but also refers to any information, whether meaningful or insignificant, and whether it is visible to humans or not. In addition, "recording medium (paper)" refers not only to recording paper used in general image forming devices, but also broadly to transportable media such as cloth, plastic film (OHP), metal plates, glass, ceramics, wood, and leather.

[0012] <First Example> (Recording device 1) First, an outline of an inkjet recording device according to a first embodiment of the present invention will be described. Fig. 1 is a perspective view showing the main internal configuration of a recording device 1 according to the first embodiment. The recording device 1 is an inkjet recording device that performs a recording operation on a recording medium while scanning a recording head in a direction substantially perpendicular to the transport direction of the recording medium. In each drawing, the scanning direction of the recording head is shown as the X direction, the transport direction of the recording medium facing the recording head is shown as the Y direction, and the vertical direction is shown as the Z direction, as necessary. In this embodiment, the X direction, Y direction, and Z direction are substantially perpendicular to each other.

[0013] The recording device 1 includes a feeding unit 2 that separates and feeds recording media one by one, a transport unit 5 that serves as a transport device that transports the recording media fed by the feeding unit 2, and a recording unit 7 that performs a recording operation on the recording media transported by the transport unit 5. Furthermore, the recording device 1 includes a drive motor 6 (see FIG. 2) that serves as a drive source that drives a transport roller 51 and the like provided in the transport unit 5, and a paper discharge unit 8 that discharges and stacks the recording media on which an image has been recorded by the recording unit 7.

[0014] The feeding unit 2 includes a stacking unit 21 for stacking recording media, and a feeding roller 22 for feeding the recording media stacked on the stacking unit 21. The recording media stacked on the stacking unit 21 are transported to the transport unit 5 by the feeding roller 22.

[0015] The conveying section 5 includes a conveying roller 51, a pinch roller 52 facing the conveying roller 51, a discharge roller 53, and a spur 54 facing the discharge roller 53. The roller 53 is long in the direction of the rotation axis, which is approximately parallel to the scanning direction of the recording head. In the conveying direction of the recording medium, the conveying roller 51 and the pinch roller 52 are provided on the upstream side of the recording unit 7, and the discharge roller 53 and the spur 54 are provided on the downstream side of the recording unit 7.

[0016] The paper discharge unit 8 includes a paper discharge tray 81 for stacking the recording medium discharged by the discharge rollers 53. An operator can collect the recording medium on which the image is recorded from the paper discharge tray 81.

[0017] Next, the transport path of the recording medium from the feeding unit 2 to the discharge unit 8 will be described in more detail. The recording medium fed from the feeding unit 2 to the transport unit 5 by the feeding roller 22 is nipped between the pinch roller 52 and the transport roller 51, and transported to the recording unit 7. The pinch roller 52 is urged against the transport roller 51 by a pinch roller holder 55.

[0018] Ink is ejected by a recording head (not shown) and nozzles (not shown) onto the recording medium transported to the recording unit 7, and an image is recorded on the recording medium. In the recording unit 7, the recording head moves in the scanning direction (X direction) to perform a recording operation at any position in the width direction of the recording medium. The recording medium on which an image has been recorded in the recording unit 7 is discharged to a paper discharge tray 81 by discharge rollers 53 and spurs 54. That is, with respect to the transport path of the recording medium from the feeding unit 2 to the paper discharge unit 8, the feeding unit 2 is located upstream of the transport unit 5 in the transport direction, and the paper discharge unit 8 is located downstream of the transport unit 5 in the transport direction.

[0019] The drive motor 6 is a drive source for rotating the transport roller 51, the discharge roller 53, and the feed roller 22. The driving force of the drive motor 6 is transmitted to the transport roller 51, etc., by a drive transmission mechanism constituted by a plurality of helical gears, etc. The drive motor 6 can be regarded as, for example, a drive source provided in the transport unit 5 serving as a transport device.

[0020] The recording medium fed from the feeding unit 2 is guided to the conveying roller 51 of the conveying unit 5 by a conveying path formed by a pinch roller holder 55 and a guide unit 56 (see FIG. 2). In addition, a platen 58 is disposed between the conveying roller 51 and the discharge roller 53 in the conveying direction of the recording medium. The platen 58 guides the recording medium so that the distance between the recording medium conveyed to the recording unit 7 and the nozzles of the recording head is kept constant.

[0021] (Transportation section 5) Next, the configuration of the transport unit 5 will be described in more detail. FIG. 2 is a perspective view of the transport unit 5 including the gear train 37. The transport unit 5 includes the gear train 37 that connects the transport roller 51 and the discharge roller 53 to the drive motor 6. When the drive motor 6 drives the transport roller 51 in the first rotation direction R1 in FIG. 2, the transport roller 51 and the discharge roller 53 rotate in a direction to transport the recording medium downstream in the transport direction. On the other hand, when the drive motor 6 drives the transport roller 51 in the second rotation direction R2 in FIG. 2, the transport roller 51 and the discharge roller 53 rotate in a direction to transport the recording medium upstream in the transport direction. In the following description, the rotation direction of the transport roller 51 and the discharge roller 53 when the recording medium is transported downstream in the transport direction is referred to as forward rotation, and the rotation direction of the transport roller 51 and the discharge roller 53 when the recording medium is transported upstream in the transport direction is referred to as reverse rotation.

[0022] The recording medium fed from the feeding section 2 is guided by the pinch roller holder 55 and the guide section 56, and fed to the transport roller 51. An end detection lever 57 is provided on the pinch roller holder 55. When the recording medium passes above the pinch roller holder 55, the end detection lever 57 is rotated, whereby the leading end position and the trailing end position of the recording medium are detected by the end detection lever 57.

[0023] The drive amount of the drive motor 6 is detected by an encoder (not shown). Various controls such as PID control are performed to control the speed and drive amount of the drive motor 6. An end detection lever 57 detects the leading end position of the recording medium during a feeding operation, and determines whether a recording operation or an ejection operation is performed. When the trailing end position of the recording medium is detected at this time, the actual length of the recording medium in the transport direction can be measured based on the amount of drive of the drive motor 6 required until the leading end position and the trailing end position are detected.

[0024] The recording medium fed to the transport rollers 51 undergoes skew correction and other operations before being transported to the recording unit 7. A recording head installed in the recording unit 7 performs a recording operation on the recording medium transported to the recording unit 7. The recording medium transported from the transport rollers 51 is guided by a platen 58 and a spur base 59, and reaches the discharge rollers 53. During the recording operation on the recording medium, the recording medium is transported by the transport rollers 51, or the discharge rollers 53, or both. Then, the recording medium on which the image has been recorded is discharged to the paper output tray 81 by the discharge rollers 53.

[0025] (Gear train 37) Next, the configuration of the gear train 37 located at the end of the conveying section 5 in the rotation axis direction of the conveying roller 51 will be described in more detail. FIG. 3 is a top view showing the configuration of the gear train 37 and peripheral members. The gear train 37 includes a drive motor gear 371 press-fitted into the drive motor 6, a conveying roller gear 372 press-fitted into the conveying roller 51, and a discharge roller gear 373 press-fitted into the discharge roller 53 and rotates integrally with the discharge roller 53. The gear train 37 further includes a conveying idler gear 374 meshing with the drive motor gear 371 and the conveying roller gear 372, and a discharge idler gear 375 meshing with the discharge roller gear 373 and the conveying roller gear 372. The drive motor gear 371, the conveying roller gear 372, the discharge roller gear 373, the conveying idler gear 374, and the discharge idler gear 375 are all helical gears, and the tooth trace direction is inclined with respect to the rotation axis direction. By using helical gears for the gears used in the gear train 37, the impact noise when the gears collide with each other can be reduced compared to when spur gears are used.

[0026] The conveying roller gear (first helical gear) 372 has a two-stage gear configuration. By configuring the conveying roller gear 372 in two stages, the strength of the gear train 37 can be improved compared to a configuration in which a plurality of gears are provided instead of the conveying roller gear 372. A first gear portion 372a of the conveying roller gear 372 meshes with a conveying idler gear (second helical gear) 374, and is drivingly connected to a drive motor gear 371 via the conveying idler gear 374. A second gear portion 372b of the conveying roller gear 372 meshes with a discharge idler gear (third helical gear) 375, and is drivingly connected to a discharge roller gear (fourth helical gear) 373 via the discharge idler gear 375. The conveying roller gear 372, the drive motor gear 371, and the discharge roller gear 373 are configured to rotate in the same direction, and the conveying roller 51 and the discharge roller 53 always rotate in the same direction.

[0027] The driving force of the drive motor 6 is transmitted from the drive motor gear 371 to the conveying idler gear 374, from the conveying idler gear 374 to the conveying roller gear 372, from the conveying roller gear 372 to the discharge idler gear 375, and from the discharge idler gear 375 to the discharge roller gear 373. The tooth trace direction of the first gear portion 372a of the conveying roller gear 372 and the tooth trace direction of the second gear portion 372b are oriented in the same direction. Therefore, the thrust force that the conveying roller gear 372 receives from the conveying idler gear 374 and the thrust force that the conveying roller gear 372 receives from the discharge idler gear 375 are always oriented in the opposite direction. In this way, the fact that the conveying roller gear 372 is configured so that the thrust force that it receives from the conveying idler gear 374 and the thrust force that it receives from the discharge idler gear 375 are oriented in the opposite direction is a characteristic of the present invention.

[0028] The conveying section 5 further includes a conveying roller spring (first pressing means) 376 as a pressing means for pressing the conveying roller (first conveying roller) 51, and a discharge roller spring (second pressing means) 377 as a pressing means for pressing the discharge roller (second conveying roller) 53. The conveying roller spring 376 and the discharge roller spring 377 are both biasing members disposed so that their elastic force acts in the direction of the rotation axis of the conveying roller 51. In this embodiment, the conveying roller spring 376 is a biasing member for biasing the conveying roller 51. The direction in which the conveying roller 51 is biased is the same as the direction in which the discharge roller spring 377 biases the discharge roller 53. In the following description, the pressing direction in which the conveying roller spring 376 presses the conveying roller 51 in the rotation axis direction of the conveying roller 51 is referred to as a first direction D1, and the second direction D2 is opposite to the first direction D1. In this embodiment, the gear train 37 is provided at the end of the conveying section 5 in the first direction D1.

[0029] The conveying section 5 further includes a regulating member (first regulating means) 378 as a regulating means for regulating the movement of the conveying roller 51 in the first direction D1, and a regulating member (second regulating means) 379 as a regulating means for regulating the movement of the discharge roller 53 in the first direction D1. That is, the conveying roller 51 and the discharge roller 53 are regulated in the first direction D1 by the regulating means while being pressed in the first direction D1 by the pressing means. In other words, the conveying roller spring 376 presses the conveying roller 51 against the regulating member 378, and the discharge roller spring 377 presses the discharge roller 53 against the regulating member 379. Note that the conveying roller 51 and the discharge roller 53 may be configured to be movable by the clearance between the components when a force exceeding the pressing force of the pressing means acts in the second direction D2 opposite to the first direction D1.

[0030] Next, the mechanism that restricts the movement of the transport roller 51 in the first direction D1 will be described in detail. Fig. 4 is a cross-sectional view showing the movement restriction mechanism of the transport roller 51. The movement restriction mechanism of the transport roller 51 in this embodiment includes a bottom 386 that is fixed to the main body of the recording apparatus, and a restriction member 378 that is positioned with respect to the bottom 386. The restriction member 378 in this embodiment is a bushing into which the transport roller 51 is inserted.

[0031] Further, grooves for attaching a first slit ring 382 and a second slit ring 384 are formed on the outer circumferential surface of the conveying roller 51. The first slit ring 382 is located on the first direction D1 side with respect to the conveying roller spring 376, and the second slit ring 384 is located on the second direction D2 side with respect to the conveying roller spring 376.

[0032] In the rotation axis direction of the conveying roller 51, the conveying roller spring 376 is located between the first slit ring 382 and the regulating member 378. The conveying roller spring 376 is disposed so as to extend in a direction parallel to the rotation axis direction of the conveying roller 51. Therefore, the conveying roller spring 376 urges the conveying roller 51 in the first direction D1 via the first slit ring 382, ​​and urges the regulating member 378 in the second direction D2.

[0033] In the rotation axis direction of the conveying roller 51, the surface of the second slit ring 384 facing the first direction D1 faces the surface of the regulating member 378 facing the second direction D2. The conveying roller 51 is biased in the first direction D1 by the conveying roller spring 376, so that the second slit ring 384 abuts against the regulating member 378. The conveying roller 51 is restricted in its movement in the first direction D1 by the regulating member 378. The movement regulating mechanism including the regulating member 379 that regulates the movement of the discharge roller 53 in the first direction D1 has the same configuration as the movement regulating mechanism of the conveying roller 51, so a description thereof will be omitted. Note that the conveying device according to the present invention is not limited to the mechanism that regulates the movement of the conveying roller 51 and the discharge roller 53 in the first direction D1, and other known movement regulating mechanisms can be applied.

[0034] (Force acting on the conveying roller 51) Next, a force acting on the conveying roller 51 in the rotation axis direction when the gear train 37 is driven will be described. A gear unit that meshes with the conveying roller gear 372 and generates a thrust force on the conveying roller 51 includes a conveying idler gear 374 and a discharge idler gear 375. In addition, the conveying roller 51 is pressed in the first direction D1 by a conveying roller spring 376.

[0035] First, when the conveying roller 51 rotates in the first rotation direction R1, that is, when the conveying roller 51 rotates in the forward direction, Next, the forces acting on the transport roller 51 will be described. Fig. 5 is a top view showing a state when the transport roller 51 rotates forward and the recording medium is transported downstream in the transport direction. Fig. 5 shows the thrust force that the transport roller gear 372 receives from the transport idler gear 374 as force F1, the thrust force that the transport roller gear 372 receives from the discharge idler gear 375 as force F2, and the pressing force that the transport roller 51 receives from the transport roller spring 376 as force F3.

[0036] The gear teeth are oriented such that, when the drive motor 6 is driven in a direction to rotate the conveying roller 51 forward, the force F1 acts in the first direction D1 and the force F2 acts in the second direction D2. The conveying roller spring 376 biases the conveying roller 51 in the first direction D1. Therefore, assuming that the resultant force FC1 acting on the conveying roller 51 acts in the first direction D1, the resultant force FC1 can be expressed as FC1=F1-F2+F3.

[0037] The forces F1 and F2 vary depending on the transport conditions, such as the transport speed and the type of recording medium. Meanwhile, the force F3 depends on the elastic force of the transport roller spring 376. In this embodiment, the force F3 is set to satisfy the relationship F3>-F1+F2 within the assumed transport conditions. The resultant force FC1 acts in the first direction D1, and the transport roller 51 is biased in the first direction D1.

[0038] Next, a force acting on the transport roller 51 when the transport roller 51 rotates in the second rotation direction R2, i.e., rotates in the reverse direction, will be described. Fig. 6 is a top view showing the state when the transport roller 51 rotates in the reverse direction and the recording medium is transported to the upstream side in the transport direction.

[0039] When the drive motor 6 drives in a direction to rotate the conveying roller 51 in the reverse direction, the force F1 acts in the second direction D2, and the force F2 acts in the first direction D1. The conveying roller spring 376 also biases the conveying roller 51 in the first direction D1. Therefore, the resultant force FC1 acting on the conveying roller 51 in the first direction D1 is expressed as FC1=-F1+F2+F3. In this embodiment, the force F3 is set so as to satisfy the relationship F3>F1-F2 within the assumed conveying conditions. That is, the resultant force FC1 in the rotation axis direction of the conveying roller 51 acts in the first direction D1, and the conveying roller 51 is biased in the first direction D1.

[0040] As described above, the resultant force FC1 of the force F3 which is the pressing force of the conveying roller spring 376 and the forces F1 and F2 which are the thrust forces received by the conveying roller gear 372 acts in the first direction D1 regardless of the rotation direction of the conveying roller 51. For example, when the conveying roller 51 rotates in the reverse direction and the force F1 is greater than the force F2, the thrust force acts in the second direction D2, but since the force F3 satisfies the relationship F3>F1-F2, the resultant force FC1 acts in the first direction D1. In other words, in this embodiment, when the thrust force received by the conveying roller gear 372 acts in the second direction D2, the pressing force of the conveying roller spring 376 is set to be greater than the thrust force.

[0041] With the above-described configuration, the resultant force FC1 acts in the first direction D1 regardless of whether the transport roller 51 rotates forward or reverse. That is, even when the rotation direction of the transport roller 51 switches, the transport roller 51 is always biased in the first direction D1. The movement of the transport roller 51 due to the resultant force FC1 is regulated by the regulating member 378 regardless of the rotation direction of the transport roller 51. That is, with the configuration of this embodiment, the movement of the transport roller 51 is always regulated when the transport roller 51 is driven, so that it is possible to prevent printing defects such as deterioration of print quality and paper jams.

[0042] Furthermore, the conveying roller 51 is pressed against the pinch roller 52 via the recording medium, thereby suppressing movement of the conveying roller 51 in the direction of the rotation axis. Therefore, the pressing force of the pinch roller 52 also contributes to preventing printing defects such as deterioration of print quality and paper jams.

[0043] Furthermore, in the above-mentioned configuration, the force F1 that the conveying roller gear 372 receives from the conveying idler gear 374 and the force F2 that the conveying roller gear 372 receives from the discharge idler gear 375 always face in opposite directions. Therefore, it is not necessary to make the force F3 excessively large in order to orient the resultant force FC1 in the first direction D1. In addition, the durability of the members that constitute the movement restriction mechanism of the conveying roller 51 can be improved. In this manner, in a configuration in which the helical gear that rotates integrally with the conveying roller meshes with multiple gears, the pressing force of the pressing means can be reduced by setting the tooth trace direction of each helical gear so that the thrust forces act in directions that cancel each other out.

[0044] (Force acting on the discharge roller 53) Next, a force acting on the discharge roller 53 in the rotation axis direction when the gear train 37 is driven will be described. In this embodiment, a gear unit that meshes with the discharge roller gear 373 and generates a thrust force on the discharge roller 53 includes a discharge idler gear 375. In addition, the discharge roller 53 is pressed in the first direction D1 by a discharge roller spring 377.

[0045] First, the forces acting on the discharge roller 53 when the discharge roller 53 rotates forward will be described. In Fig. 5, the thrust force that the discharge roller gear 373 receives from the discharge idler gear 375 is shown as force F4, and the pressing force that the discharge roller 53 receives from the discharge roller spring 377 is shown as force F5. In this embodiment, the absolute value of force F4 is the same as the absolute value of force F2.

[0046] The teeth of each gear are oriented such that when the drive motor 6 is driven in a direction to rotate the discharge roller 53 forward, the force F4 acts in the first direction D1. The discharge roller spring 377 urges the discharge roller 53 in the first direction D1. Therefore, assuming that the resultant force FC2 acting on the discharge roller 53 acts in the first direction D1, the resultant force FC2 is expressed as FC2=F4+F5. That is, the resultant force FC2 in the rotation axis direction of the discharge roller 53 acts in the first direction D1, and the discharge roller 53 is urged in the first direction D1.

[0047] Next, the force acting on the discharge roller 53 when the discharge roller 53 rotates in the reverse direction will be described. As shown in FIG. 6, when the drive motor 6 is driven in a direction to rotate the discharge roller 53 in the reverse direction, a force F4 acts in the second direction D2. Also, the discharge roller spring 377 urges the discharge roller 53 in the first direction D1. Therefore, the resultant force FC2 acting on the discharge roller 53 in the first direction D1 is expressed as FC2=-F4+F5. In this embodiment, the force F5 is set to satisfy the relationship F5>F4 within the assumed conveying conditions. That is, the resultant force FC2 acts in the first direction D1, and the discharge roller 53 is urged in the first direction D1.

[0048] As described above, the resultant force FC2 of the force F5 which is the pressing force of the discharge roller spring 377 and the force F4 which is the thrust force received by the discharge roller gear 373 acts in the first direction D1 regardless of the rotation direction of the discharge roller 53. In other words, in this embodiment, when the thrust force received by the discharge roller gear 373 acts in the second direction D2, the pressing force of the discharge roller spring 377 is set to be larger than the thrust force.

[0049] With the above-described configuration, the resultant force FC2 acts in the first direction D1 whether the discharge roller 53 rotates forward or reverse. Furthermore, even when the rotation direction of the discharge roller 53 switches, the discharge roller 53 is always biased in the first direction D1. The movement of the discharge roller 53 due to the resultant force FC2 is regulated by the regulating member 379 regardless of the rotation direction of the discharge roller 53. That is, with the configuration of this embodiment, the movement of the discharge roller 53 is always regulated when the discharge roller 53 is driven, thereby preventing printing defects such as deterioration of print quality and paper jams.

[0050] In addition, the discharge roller 53 is pressed against the spur 54 via the recording medium, so that the movement of the discharge roller 53 in the rotation axis direction is suppressed. It helps prevent printing defects such as reduced print quality and paper jams.

[0051] Furthermore, in the above-described configuration, the resultant force FC1 acting on the transport roller 51 and the resultant force FC2 acting on the discharge roller 53 act in the same direction. Therefore, when the same recording medium is nipped between the transport roller 51 and the pinch roller 52, and between the discharge roller 53 and the spur 54, the transport roller 51 and the discharge roller 53 do not move in opposite directions even if the transport direction is switched. Furthermore, according to the configuration of this embodiment, the recording medium is not twisted, and the transport accuracy of the recording medium is improved.

[0052] In this embodiment, the discharge roller gear 373 is configured to mesh only with the discharge idler gear 375, but in application of the present invention, the discharge roller gear 373 may be configured to mesh with a plurality of helical gears. Even with this configuration, if the pressing force of the discharge roller spring 377 is set so that the resultant force of the pressing force and the thrust force is oriented in the first direction D1, the same effect as the configuration of this embodiment can be obtained.

[0053] <Second Example> Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in that a helical output gear 380 is provided at the end of the conveying roller 51 on the second direction D2 side. In the following description of the second embodiment, the description of the same configuration as the first embodiment will be omitted, and only the characteristic configuration of the second embodiment will be described.

[0054] FIG. 7(a) is a top view showing the end of the conveying roller 51 on the second direction D2 side. FIG. 7(b) is a view showing a helical output gear 380 that rotates with the rotation of the conveying roller 51. In the conveying roller 51 according to the second embodiment, a conveying roller gear 372 is provided at the end on the first direction D1 side, and a helical output gear 380 is provided at the end on the second direction D2 side. A driven unit (not shown) driven by the rotation of the helical output gear 380 is connected to the helical output gear 380. That is, in this embodiment, the helical output gear 380 rotates with the rotation of the conveying roller 51, and the driven unit is driven. With this configuration, the conveying roller 51, the discharge roller 53, and the driven unit are driven by the drive motor 6 without providing multiple drive sources. Furthermore, according to the configuration of this embodiment, there is no need to increase the number of drive sources, so that an increase in manufacturing costs can be suppressed.

[0055] The helical output gear 380 is configured to be movable in the thrust direction of the helical output gear 380 by an amount corresponding to the clearance between the components relative to the conveying roller 51. The teeth of the helical output gear 380 are configured so that when the conveying roller 51 rotates forward, a thrust force acts on the helical output gear 380 in the second direction D2, and when the conveying roller 51 rotates reversely, a thrust force acts on the helical output gear 380 in the first direction D1.

[0056] As shown in FIG. 7B, the helical output gear 380 is provided with an abutment surface 380a extending between the inner circumferential surfaces. In addition, a notched groove 51a extending in the rotation axis direction is formed at the end of the conveying roller 51 on the second direction D2 side. When the helical output gear 380 moves in the first direction D1, the abutment surface 380a of the helical output gear 380 abuts against the end face 51b of the notched groove 51a of the conveying roller 51, and the movement of the helical output gear 380 in the first direction D1 is restricted. On the other hand, when the helical output gear 380 moves a predetermined amount in the second direction D2 from the state in which the abutment surface 380a abuts against the end face 51b, the movement of the helical output gear in the second direction D2 is restricted by a restricting member (not shown). That is, the thrust force in the first direction D1 acting on the helical output gear 380 is transmitted to the transport roller 51, but the thrust force in the second direction D2 acting on the helical output gear 380 is not transmitted to the transport roller 51.

[0057] Next, a force acting on the transport roller 51 when the gear train 37 is driven will be described. First, the forces acting on the transport roller 51 when it rotates will be described. Fig. 8 is a top view showing the state when the transport roller 51 rotates forward and transports the recording medium downstream in the transport direction. Fig. 8 shows the force F1 that the transport roller gear 372 receives from the transport idler gear 374, the force F2 that the transport roller gear 372 receives from the discharge idler gear 375, and the force F3 that the transport roller 51 receives from the transport roller spring 376. Furthermore, Fig. 8 shows the resultant force acting in the direction of the rotation axis of the transport roller 51 as a resultant force FC1.

[0058] As described above, when the drive motor 6 drives in a direction to rotate the conveying roller 51 forward, a thrust force in the second direction D2 acts on the helical output gear 380, and the helical output gear 380 moves in the second direction D2, and the movement is restricted by the restricting member. Therefore, the conveying roller 51 does not receive a force from the helical output gear 380 in the rotation axis direction of the conveying roller 51. In other words, assuming that the resultant force FC1 acting on the conveying roller 51 acts in the first direction D1, the resultant force FC1 can be expressed as FC1=F1-F2+F3, as in the first embodiment.

[0059] In this embodiment, the force F3 is set to satisfy the relationship F3>-F1+F2 within the assumed transport conditions. That is, the resultant force FC1 acts in the first direction D1, and the transport roller 51 is biased in the first direction D1.

[0060] Next, a description will be given of the force acting on the transport roller 51 when the transport roller 51 rotates in the reverse direction. Fig. 9 is a top view showing the state when the transport roller 51 rotates in the reverse direction and the recording medium is transported to the upstream side in the transport direction.

[0061] As described above, when the drive motor 6 drives in a direction to rotate the conveying roller 51 in the reverse direction, a thrust force in the first direction D1 acts on the helical output gear 380, and the helical output gear 380 moves in the first direction D1, and the movement is restricted by the conveying roller 51. With this configuration, the conveying roller 51 receives a force F6 in the first direction D1 from the helical output gear 380 in the rotation axis direction of the conveying roller 51. That is, in this embodiment, the conveying roller 51 receives a first thrust force from the conveying roller gear 372, a second thrust force from the helical output gear 380, and a pressing force from the conveying roller spring 376. Assuming that the resultant force FC1 acting on the conveying roller 51 acts in the first direction D1, the resultant force FC1 is expressed as FC1=-F1+F2+F3+F6.

[0062] In this embodiment, the force F3 is set to satisfy the relationship F3>F1-F2-F6 within the assumed conveying conditions. That is, the resultant force FC1 acts in the first direction D1, and the conveying roller 51 is biased in the first direction D1. In other words, in this embodiment, when the first thrust force received by the conveying roller gear 372 acts in the second direction D2, the resultant force of the pressing force of the conveying roller spring 376 and the second thrust force received by the helical output gear 380 is set to be larger than the first thrust force. According to this embodiment, since the force F6 acts in the first direction D1, the force F3 by the conveying roller spring 376 can be set smaller than that of the first embodiment. As a result, the durability of the members constituting the movement restriction mechanism of the conveying roller 51 can be improved.

[0063] According to the configuration of this embodiment, the conveying roller 51 can be prevented from moving in the rotation axis direction when the conveying roller 51 rotates and when the rotation direction is switched, so that printing defects can be prevented. When the force F1 acts strongly, the force F3 does not need to be set excessively large due to the action of the force F6, so the configuration of this embodiment is particularly effective. In the above configuration, the helical output gear 380 is provided at the end of the conveying roller 51 on the second direction D2 side, but in applying the present invention, the helical output gear 380 may be provided at another location on the conveying roller 51.

[0064] <Modification> The application of the present invention is not limited to the above-mentioned configuration, and can be applied to other configurations as long as the identity of the invention is not lost. For example, in the above-mentioned embodiment, the conveying roller 51 is biased in the first direction D1 while the movement of the conveying roller 51 in the first direction D1 is restricted, but the biasing direction and the restricted movement direction may be the second direction D2. Also, in the second embodiment, the helical output gear 380 is provided at the end of the conveying roller 51, but a similar output gear may be provided at the end of the discharge roller 53.

[0065] In the above embodiment, the conveying roller gear 372, which rotates integrally with the conveying roller 51, is configured to mesh with two helical gears, but the application of the present invention is not limited to this configuration. For example, the present invention can be applied to a configuration in which the conveying roller gear 372 meshes with a single helical gear or with three or more helical gears. That is, the gear unit that meshes with the conveying roller gear 372 only needs to have one or more helical gears. In either configuration, the pressing force and the tooth trace direction of the helical gear should be set so that the resultant force in the rotation axis direction of the conveying roller 51, including the pressing force of the pressing means and the thrust force received by the conveying roller 51, faces the first direction D1 regardless of the rotation direction of the conveying roller gear 372.

[0066] The disclosure of this embodiment includes the following configuration. (Configuration 1) A conveying roller for conveying the recording medium; A first helical gear that rotates integrally with the conveying roller; a gear unit that meshes with the first helical gear and generates a thrust force on the conveying roller; a restricting means for restricting movement of the conveying roller in the direction of the rotation axis; a pressing means for pressing the conveying roller in a pressing direction against the regulating means; Equipped with A conveying device characterized in that the movement of the conveying roller caused by a resultant force in the direction of the rotation axis, including the pressing force of the pressing means pressing the conveying roller and the thrust force, is regulated by the regulating means regardless of the rotation direction of the conveying roller. (Configuration 2) 2. The conveying device according to configuration 1, wherein the pressing force is greater than the thrust force when the thrust force acts in a direction opposite to the pressing direction. (Configuration 3) The gear unit includes a second helical gear and a third helical gear, 3. The conveying device according to claim 1 or 2, wherein the thrust force that the conveying roller receives from the second helical gear acts in an opposite direction to the thrust force that the conveying roller receives from the third helical gear. (Configuration 4) A drive source for driving the conveying roller is further provided, The conveying device according to configuration 3, wherein the second helical gear transmits a driving force of the driving source to the first helical gear. (Configuration 5) the first helical gear is a two-stage gear having a first gear portion meshing with the second helical gear and a second gear portion meshing with the third helical gear, 5. The conveying device according to configuration 4, wherein the first gear portion and the second gear portion have the same tooth trace direction. (Configuration 6) a second conveying roller that rotates in the same direction as the first conveying roller to convey the recording medium, when the conveying roller is a first conveying roller; a fourth helical gear that rotates integrally with the second conveying roller; Further comprising: the fourth helical gear meshes with the third helical gear, The conveying device according to configuration 4 or 5, wherein the third helical gear generates a thrust force on the second conveying roller. (Configuration 7) When the restricting means is a first restricting means and the pressing means is a first pressing means, a second regulating means for regulating movement of the second conveying roller in the direction of the rotation axis; a second pressing means for pressing the second conveying roller against the second regulating means in the pressing direction; Further comprising: The conveying device described in configuration 6, characterized in that movement of the second conveying roller caused by a resultant force in the rotational axis direction of the second conveying roller, including a pressing force applied by the second pressing means to the second conveying roller and a thrust force received by the third helical gear by the second conveying roller, is regulated by the regulating means regardless of a rotational direction of the second conveying roller. (Configuration 8) a helical output gear that rotates in association with the rotation of the conveying roller; a driven unit driven by the helical output gear; Further comprising: The conveying device described in any one of configurations 1 to 7, characterized in that the helical output gear presses the conveying roller in the pressing direction when the conveying roller rotates in a first rotation direction, and does not press the conveying roller when the conveying roller rotates in a second rotation direction opposite to the first rotation direction. (Configuration 9) The conveying device according to configuration 8, wherein the helical output gear is configured to be movable in the direction of the rotation axis of the conveying roller and has an abutment surface that abuts against the conveying roller when the helical output gear moves in the pressing direction. (Configuration 10) When the thrust force that the conveying roller receives from the gear unit is defined as a first thrust force, the resultant force acting on the conveying roller further includes a second thrust force by which the helical output gear presses the conveying roller in the pressing direction, 10. The conveying device according to claim 8 or 9, wherein a resultant force of the pressing force and the second thrust force is greater than the first thrust force when the first thrust force acts in a direction opposite to the pressing direction. (Configuration 11) 11. The conveying device according to any one of configurations 1 to 10, wherein the pressing means is a biasing member disposed so as to exert an elastic force in the direction of the rotation axis of the conveying roller. (Configuration 12) 12. The conveying device according to any one of configurations 1 to 11, wherein the regulating means is a bushing through which the conveying roller passes. (Configuration 13) a recording unit that performs a recording operation on a recording medium; A conveying device according to any one of the configurations 1 to 12 for conveying a recording medium; A recording device comprising: [Explanation of symbols]

[0067] 5...conveying section (conveying device), 51...conveying roller, 372...conveying roller gear (first helical gear), 376...conveying roller spring (pressing means), 378...regulating member (regulating means)

Claims

1. a conveying roller for conveying the recording medium; a first helical gear that rotates integrally with the conveying roller; a gear unit that meshes with the first helical gear and generates a thrust force on the conveying roller; a restricting means for restricting movement of the conveying roller in the direction of the rotation axis; a pressing means for pressing the conveying roller in a pressing direction against the regulating means; Equipped with movement of the conveying roller caused by a resultant force in the rotation axis direction, including the thrust force and the pressing force of the pressing means pressing the conveying roller, is regulated by the regulating means, regardless of the rotation direction of the conveying roller; the gear unit includes a second helical gear and a third helical gear, A conveying device, wherein the thrust force that the conveying roller receives from the second helical gear acts in an opposite direction to the thrust force that the conveying roller receives from the third helical gear.

2. 2. The conveying device according to claim 1, wherein the pressing force is greater than the thrust force when the thrust force acts in a direction opposite to the pressing direction.

3. Further, a drive source for driving the conveying roller is provided, 2. The conveying device according to claim 1, wherein the second helical gear transmits the driving force of the driving source to the first helical gear.

4. the first helical gear is a two-stage gear having a first gear portion that meshes with the second helical gear and a second gear portion that meshes with the third helical gear, 4. The conveying device according to claim 3, wherein the first gear portion and the second gear portion have the same tooth trace direction.

5. When the conveying roller is a first conveying roller, a second conveying roller rotates in the same direction as the first conveying roller to convey the recording medium; a fourth helical gear that rotates integrally with the second conveying roller; Further provided with the fourth helical gear meshes with the third helical gear, 4. The conveying device according to claim 3, wherein the third helical gear generates a thrust force on the second conveying roller.

6. When the restricting means is a first restricting means and the pressing means is a first pressing means, a second restricting means for restricting movement of the second conveying roller in the direction of the rotation axis; a second pressing means for pressing the second conveying roller against the second regulating means in the pressing direction; Further provided with 6. The conveying device according to claim 5, wherein movement of the second conveying roller caused by a resultant force in the direction of the rotation axis of the second conveying roller, the resultant force including the pressing force of the second pressing means pressing the second conveying roller and the thrust force that the second conveying roller receives from the third helical gear, is regulated by the second regulating means regardless of the rotation direction of the second conveying roller.

7. a helical output gear that rotates in accordance with the rotation of the conveying roller; a driven unit driven by the helical output gear; Further provided with 2. The conveying device according to claim 1, wherein the helical output gear presses the conveying roller in the pressing direction when the conveying roller rotates in a first rotation direction, and does not press the conveying roller when the conveying roller rotates in a second rotation direction opposite to the first rotation direction.

8. The conveying device according to claim 7, wherein the helical output gear is configured to be movable in the direction of the rotation axis of the conveying roller and has an abutment surface that abuts against the conveying roller when it moves in the pressing direction.

9. When the thrust force that the conveying roller receives from the gear unit is defined as a first thrust force, the resultant force acting on the conveying roller further includes a second thrust force that presses the conveying roller in the pressing direction by the helical output gear, 8. The transport device according to claim 7, wherein a resultant force of the pressing force and the second thrust force is greater than the first thrust force when the first thrust force acts in a direction opposite to the pressing direction.

10. 2. The conveying device according to claim 1, wherein the pressing means is a biasing member disposed so as to exert an elastic force in the direction of the rotation axis of the conveying roller.

11. 2. The conveying device according to claim 1, wherein the restricting means is a bushing through which the conveying roller passes.

12. a recording unit that performs a recording operation on a recording medium; a conveying device according to any one of claims 1 to 11 that conveys a recording medium; A recording device comprising:

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