Driving switching mechanism and image printing equipment

Abstract

Provided are a drive switching mechanism and an image printing apparatus that can miniaturize an apparatus. To this end, a configuration is applied in which the revolution movement of the planetary gear is not restricted in a region other than a region from a first position to a second position during a drive switching operation.

Description

Technical Field

[0001] The invention relates to a drive switching mechanism and an image printing device. Background Art

[0002] A drive switching mechanism is known that selectively distributes and transmits the driving force of a single driving source to a plurality of mechanisms. Japanese Patent Publication No. 2009-274304 discloses a drive switching mechanism, in which a power transmission unit including an arm member along the axial direction of a driving shaft moves between a first position and a second position, in the first position, a rotational torque is transmitted, and in the second position, a driven unit to which the rotational torque is transmitted is selected. Japanese Patent Publication No. 2009-274304 describes a drive switching mechanism including an intermediate position between the first position and the second position, in which the rotational torque is neither transmitted to the driven unit nor to the arm member. Japanese Patent Publication No. 2009-274304 describes a drive switching mechanism that can return from an intermediate position to a first position by moving the power transmission unit from the intermediate position to the second position.

[0003] However, in the device described in Japanese Patent Application Laid-Open No. 2009-274304, the revolution of the planetary arm is constrained at the second position in the path of the power transmission unit returning from the intermediate position to the first position. In addition, in the case of switching the driven unit to which the drive is transmitted, it is necessary to further move the power transmission unit in the axial direction of the drive shaft to release the constrained revolution of the planetary arm at the second position. As a result, the drive switching mechanism has always been large in the power axis direction, making it difficult to achieve miniaturization. Summary of the invention

[0004] Therefore, the present invention provides a drive switching mechanism and an image printing apparatus that can miniaturize the apparatus.

[0005] Therefore, the drive switching mechanism of the present invention is a drive switching mechanism as follows, which includes: a drive shaft, which is rotated by a drive source; a driven unit, which includes a fixed shaft, and the driven unit is transmitted with the driving force of the drive shaft; a drive switching unit, which switches the transmission of the driving force of the drive shaft to the driven unit by moving in the thrust direction of the drive shaft; and a planetary gear, which is provided to the drive switching unit, can orbit around the drive shaft when not engaged with the fixed shaft, and can transmit the driving force of the drive shaft to the driven unit when engaged with the fixed shaft, wherein the drive switching unit can move to: a first position in which the driving force of the drive shaft is transmitted to the driven unit when engaged with the fixed shaft, a second position in which the driving force of the drive shaft is not transmitted to the driven unit when engaged with the fixed shaft, and a third position in which the planetary gear can orbit when not engaged with the fixed shaft, and when moving from the second position to the first position, the drive switching unit passes through the third position without allowing the planetary gear to orbit.

[0006] According to the present invention, it is possible to provide a drive switching mechanism and an image printing apparatus that can downsize the apparatus.

[0007] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a perspective view illustrating the internal structure of an image printing apparatus including a drive transmission mechanism;

[0009] Figure 2 is a block diagram of an image printing device;

[0010] Figure 3 is a side view illustrating the interior of the image printing apparatus;

[0011] Figure 4A and Figure 4B is a perspective view illustrating a driving unit of an image printing apparatus;

[0012] Figure 5A and Figure 5B is a perspective view illustrating a drive switching mechanism;

[0013] FIG. 6A to FIG. 6C is a diagram illustrating a drive switching position in a drive switching unit;

[0014] FIG. 7A to FIG. 7D is a diagram illustrating a drive switching operation of returning from a second position to a first position;

[0015] FIG. 8A to FIG. 8Dis a diagram illustrating a drive switching unit;

[0016] 9A to 9C is a diagram illustrating a drive switching unit through which a fixed shaft is inserted;

[0017] FIG. 10A to FIG. 10C is a perspective view illustrating a portion causing the swing; and

[0018] Fig.11 is a table illustrating a list of swing components. DETAILED DESCRIPTION

[0019] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0020] Figure 1 : is a stereoscopic diagram illustrating the internal structure of the image printing device M including the drive transmission mechanism in the present embodiment. The image printing device M is a multifunctional peripheral device, which includes a printing unit and a scanning unit (not shown) configured on the printing unit, and various types of processing related to image printing operations and reading operations can be performed by the printing unit and the scanning unit alone or in cooperation with each other. The scanning unit includes an automatic document feeder (ADF) and a flatbed scanner (FBS), and can read an original document automatically fed by the ADF, and read (scan) an original document placed on the original document plate of the FBS by a user. Note that although the present embodiment describes a multifunctional peripheral device having both a printing unit and a scanning unit as an example, a mode that does not include a scanning unit can also be applied.

[0021] The printing unit includes a first feeding unit 1, a second feeding unit 2, a conveying unit 3, a printing unit 4, a maintenance unit 5, a driving unit 6, and a discharging unit 8. Before performing printing on a printing medium, a user stacks the printing medium on the first feeding unit 1 and the second feeding unit 2. The conveying unit 3 accurately conveys the printing medium fed from each feeding unit to a printable position. The printing unit 4 prints an image on the printing medium conveyed by the conveying unit 3. The maintenance unit 5 performs maintenance on the printing unit 4. The driving unit 6 switches and transmits the drive of any one of the first feeding unit 1, the second feeding unit 2, and the maintenance unit 5 using the drive of the conveying motor 31 included in the conveying unit 3. The discharging unit 8 includes a printing medium stacking unit 81 and an extension tray 82, which can be drawn out from the image printing apparatus M so as to support the printing medium even when the size of the printing medium is large. All of these units are fastened to the base 7 and form a printing unit.

[0022] Figure 2901 is a block diagram of the image printing apparatus M in the present embodiment. The MPU 901 controls the operation of each unit, the processing of data, etc. The ROM 902 stores programs and data executed by the MPU 901. The RAM 903 temporarily stores the processing data executed by the MPU 901 and the data received from the host 906. The print head 42 is controlled by the print head driver 942.

[0023] The carriage 41 is driven by a carriage motor 43. The carriage motor 43 is controlled by a carriage motor driver 943. The conveying roller 32 and the discharge roller 34 are driven by the conveying motor 31. The conveying motor 31 is controlled by a conveying motor driver 931. The host 906 includes a printer driver 9061, and in the case where the user instructs to perform a printing operation, the printer driver 9061 communicates with the image printing apparatus M by processing printing information such as a print image and image quality. The MPU 901 transmits and receives a print image and the like to and from the host 906 via the I / F unit 905.

[0024] Figure 3 FIG. 2 is a side view illustrating the interior of the image printing apparatus M in the present embodiment. Figure 3 A series of processes for printing an image on a printing medium by the image printing apparatus M is described. In the case where a user sets a printing medium on which an image is to be printed, there are two methods described below. In the first method, the printing medium P1 is set on the first feeding unit 1 by stacking the printing medium P1 on the platen 11. In the second method, the printing medium P2 is set on the second feeding unit 2 by stacking the printing medium P2 on a sheet cassette 21 that is attachable to and detachable from the image printing apparatus M and mounting the sheet cassette 21 on the image printing apparatus M.

[0025] Once the user inputs the printing information and gives the image printing apparatus M an instruction to execute printing, the conveying motor 31 (see FIG. Figure 1 ) starts to rotate forward. In the case where the printing medium P1 is fed from the first feeding unit 1, the driving unit 6 and the first feeding unit 1 are drivingly connected to each other. Feeding starts in the case where the pressing plate 11 contacts the first feeding roller 12 that rotates by receiving the drive of the conveying motor 31. At a position facing the first feeding roller 12, a separation roller 13 that provides resistance in the feeding direction of the printing medium P1 is arranged, and only the uppermost paper of the printing medium P1 stacked on the pressing plate 11 is fed to the conveying unit 3 by the separation roller 13 as shown by the arrow F1.

[0026] Furthermore, in the case where the print medium P2 is fed from the second feeding unit 2, the driving unit 6 and the second feeding unit 2 are drivingly connected to each other. The drive of the conveying motor 31 is transmitted to the second feeding shaft gear 23 via the driving unit 6. The second feeding roller 25 rotates via the second feeding shaft gear 23 to the plurality of second feeding idle gears 24, and feeds only the uppermost sheet of the print medium P2 stacked on the sheet cassette 21. A separation unit 26 that provides resistance to the fed print medium P2 in the feeding direction is provided, whereby, even in the case where a plurality of print media P2 are fed, the uppermost sheet in contact with the second feeding roller 25 is fed by the separation unit 26. Next, the drive is transmitted to the intermediate gear 27 and the intermediate roller 28 via the gear transmission system, not shown, of the driving unit 6. The driven roller 29 is arranged at a position facing the intermediate roller 28 and feeds the print medium P2 fed from the second feeding roller 25 to the conveying unit 3 as indicated by the arrow F2.

[0027] Once the print medium fed from each feeding unit passes the detection lever 14, a conveying roller pair consisting of a conveying roller 32 and a nip roller 33 driven by the conveying roller 32 aligns the positions of the left and right end portions of the print medium in the width direction relative to the conveying direction.

[0028] The printing unit 4 includes a carriage 41 on which a print head 42 is mounted, a frame 44 supporting the carriage 41, and a frame guide rail 45. The carriage 41 reciprocates along a scanning direction perpendicular to the conveying direction of the fed print medium. On the print medium conveyed by the conveying roller pair, when the print medium passes over a platen 36 disposed at a position facing the printing unit 4 and exerting force on the print medium, an image is printed by ink ejected from the print head 42 during scanning by the carriage 41. In the case of printing an image on only one side of the print medium, the print medium is discharged to the discharge unit 8 by the discharge roller pair composed of the discharge roller 34 and the ratchet 35 as indicated by the arrow F3, and printing is finished.

[0029] In the case of printing an image on both sides of the print medium, after the image printing on one side of the print medium is completed, the conveying motor 31 is rotated in the reverse direction from the state where the rear end of the print medium is clamped. Therefore, the discharge roller pair and the conveying roller pair rotate in the reverse direction from the conveying direction of the printed image, and the print medium can be conveyed along the reverse conveying path as shown by arrow F4. Once the rear end of the print medium in the conveying direction passes the conveying roller pair, the conveying motor 31 is switched to forward rotation, and the positions of the left and right end portions in the width direction of the print medium are aligned again by the conveying roller pair. Thereafter, the operation of printing the image is performed on the other side of the print medium, and the print medium on which the image is printed is discharged to the discharge unit 8 through the discharge roller pair composed of the discharge roller 34 and the ratchet 35 as shown by arrow F3.

[0030] Figure 4A and Figure 4B FIG. 4 is a perspective view illustrating a driving unit 6 of the image printing apparatus M in the present embodiment. Figure 5A and Figure 5B 1 is a perspective view illustrating a drive switching unit in the drive unit 6 . Figure 5A The diagram shows the drive switching mechanism after assembly. Figure 5B The diagram shows the drive switching unit before assembly.

[0031] Conveyor motor 31 (see Figure 1 ) is transmitted to the drive unit 6 via the conveying roller output gear 37 that rotates integrally with the conveying roller 32. The drive unit 6 includes a drive input gear 614 that meshes with the conveying roller output gear 37, a drive base 611 that holds a plurality of gears that transmit drive to a plurality of driven units that are provided, a drive cover 612, and a positioning unit 663 that performs positioning of the drive switching unit. The drive is transmitted from the drive input gear 614 to the sun gear 631 via a plurality of gears.

[0032] The sun gear 631 and the sun gear 632 are assembled to the drive shaft 635 in a D-cut shape and rotate as a whole. The planetary gear 633 can transmit the driving force, meshes (engages) with the sun gear 632, and acts as a planetary gear mechanism. The planetary arm 634 holding the planetary gear 633 has a structure that can rotate around the same axis as the drive shaft 635 and can move in the thrust direction. In addition, the trigger holder 641, the trigger holder spring 642 and the drive shaft gear 643 are arranged on the same axis as the drive shaft 635. The drive shaft gear 643 is assembled to the drive shaft 635 in a D-cut shape and rotates as a whole. The trigger holder 641 can be displaced in the thrust direction of the drive shaft 635, and the planetary arm 634 also synchronizes the movement in the thrust direction. In addition, the planetary arm 634 and the drive shaft 635 are connected to each other by a connecting member 637, whereby the planetary arm 634 can revolve around the drive shaft 635.

[0033] The driving shaft 635 is rotatably supported by the driving base 611 and the driving cover 612, and is arranged parallel to the scanning direction of the carriage 41. The driving switching unit includes a sun gear 632, a planetary gear 633, a planetary arm 634, an introduction member 636, and a trigger holder 641. The driving switching unit is constantly urged in the -x direction by a trigger holder spring 642.

[0034] The driving base 611 includes a first fixed shaft 6111, a second fixed shaft 6112, and a third fixed shaft 6113. These fixed shafts are arranged on the orbital trajectory of the planetary gear 633 relative to the planetary arm 634. An axis hole into which the fixed shaft can be inserted is formed in each of the planetary arm 634 and the introduction member 636, and once the fixed shaft is inserted into the axis hole, the orbital movement of the planetary arm 634 is restricted. After the fixed shaft is inserted into the planetary arm 634, a plurality of drive input gears are respectively arranged around the fixed shaft so as to transmit the drive to each drive unit.

[0035] When the first fixed shaft 6111 is inserted into the shaft hole of the planetary arm 634 and the shaft hole of the introduction member 636, the maintenance input gear 651 and the planetary gear 633 are meshed with each other. When the second fixed shaft 6112 is inserted, the second feed input gear 621 and the planetary gear 633 are meshed with each other. When the third fixed shaft 6113 is inserted, the first feed input gear 15 and the planetary gear 633 are meshed with each other. When the input gear of each drive unit is meshed with the planetary gear 633, drive can be transmitted to each drive unit.

[0036] FIG. 6A to FIG. 6C FIG. 2 is a diagram illustrating the drive switching position in the drive switching unit of the present embodiment. FIG. 6A to FIG. 6C In the side view of FIG. 66, components other than the moving gear are illustrated in a manner that aligns the positions in the X direction so that the positions of the gears during drive switching can be compared. In addition, a stereoscopic view of the clutch 6632 portion corresponding to the state of each side view is also illustrated.

[0037] The locking unit 6412 is set to the trigger holder 641 so that the drive switching unit can be locked at multiple positions in the thrust direction of the drive shaft 635, and the positioning unit 663 is set to the drive unit 6 to be engaged with the locking unit 6412. The positioning unit 663 includes a clutch 6632, which holds the position of the drive shaft 635 in the axial direction by engaging with the locking unit 6412 and a clutch spring 6633, and the clutch spring 6633 generates a bias to prevent separation between the locking unit 6412 and the clutch 6632. In addition, the positioning unit 663 includes a clutch holder 6631, which holds the clutch 6632 and the clutch spring 6633. Note that although the first fixed shaft 6111 is Figure 6C It is shown as a fixed shaft in the subsequent figures, but the same applies to the second fixed shaft 6112 and the third fixed shaft 6113.

[0038] Fig. 6AThe diagram shows a state where the drive switching unit is positioned at the first position. At a position where the locking unit 6412 is engaged with the first locking unit 6632a provided to the clutch 6632, any one of the first to third fixed shafts is inserted into the shaft hole of the planetary arm 634 and the shaft hole of the introduction member 636, and the revolution of the planetary arm 634 is restricted. Then, the drive switching unit connects the first feeding unit 1, the second feeding unit 2, or the maintenance unit 5 to the drive shaft according to the inserted fixed shaft.

[0039] Figure 6B The diagram shows a state in which the drive switching unit is positioned at the second position in the moving path starting from the first position. The drive switching unit is displaced by a predetermined amount in the thrust direction of the drive shaft 635 by the carriage 41, thereby locking the drive switching unit in a position where the locking unit 6412 is engaged with the second locking unit 6632b provided to the clutch 6632. As in the first position, the revolution of the planetary arm 634 is constrained by any fixed axis. In addition, unlike the first position, each input gear of the first feeding unit 1, the second feeding unit 2 or the maintenance unit 5 is in a non-connected state with the planetary gear 633 of the drive switching unit.

[0040] The state in which the drive switching unit is positioned at the second position is used, for example, in the case where the feeding of the last print medium from the first feeding unit 1 and the second feeding unit 2 is stopped by a print instruction. In the present embodiment, a configuration is applied in which the drive connection state is obtained when the drive switching unit is positioned at the first position and the non-connection state is obtained when the drive switching unit is positioned at the second position; however, a configuration may be applied in which the non-connection state of the drive switching unit is obtained at the first position and the connection state is obtained at the second position.

[0041] Figure 6C The diagram illustrates a state in which the first fixed axis is removed from the axis hole of the planetary arm 634 and the axis hole of the introduction member 636 and the planetary arm 634 is positioned in a revolution position (hereinafter, also referred to as the third position) that allows revolution. This is a state in which the slide 41 further pushes (moves) the drive switching unit a predetermined amount from the second position in the thrust direction of the drive shaft 635. With the locking unit 6412 positioned in the +X direction starting from the inclined surface 6632c set to the clutch 6632, the clutch 6632 pivots counterclockwise as indicated by the arrow through the inclined surface 6632d and the clutch spring 6633. The portion from the inclined surface 6632d to the first locking unit 6632a through which the arrow passes is formed by a plurality of curved surfaces. The locking unit 6412 moves as indicated by the arrow, is then positioned in the first locking unit 6632a and returns Fig. 6A That is, the drive switching unit starts from the second position and returns to the first position via the third position (revolution position).

[0042] like Figure 6CAs shown, at the revolution position of the planetary arm 634 pressed by the carriage 41, the planetary gear revolves by the forward and reverse rotation operation of the driving source, and the planetary gear can be arranged on the same axis as each fixed shaft. By retracting the carriage 41 in this state, the predetermined fixed shaft 6111 is inserted through the shaft hole of the planetary gear 633 and the shaft hole of the planetary arm 634.

[0043] FIG. 7A to FIG. 7D 1 is a diagram for explaining a state in which a moving drive switching unit is used for drive switching by comparing a conventional configuration with the configuration of the present embodiment. Fig. 7A and Figure 7B 1 and 2 are diagrams respectively illustrating a state in which the drive switching unit in the conventional configuration and the present embodiment returns from the second position to the first position without switching the drive. Figure 7B In the illustrated embodiment, the drive switching unit is in the third position, ie, the position where the planetary gear 633 of the drive switching unit can revolve.

[0044] on the other hand, Figure 7C and Fig.7D 1 and 2 are diagrams respectively illustrating the state in which the drive switching unit in the conventional configuration and the present embodiment is in the orbital position and can switch the drive. Note that in the present embodiment, Figure 7B The diagram shows the situation of returning from the second position to the first position. Fig.7D The diagram shows that the orbital positions are the same.

[0045] In other words, in the conventional configuration, there is a position for driving the switching unit to return from the second position to the first position and a revolution position for performing the revolution operation. Fig. 7A The position of the conventional structure shown is the middle position. The middle position is a position for the drive switching unit to return from the second position to the first position, and is a position where the drive switching unit moves within the same fixed axis when the drive switching unit returns from the second position to the first position. In this position, it is possible to return from the second position to the first position without switching the drive.

[0046] In the traditional structure, Fig. 7A The first fixed shaft 702 is inserted into the shaft hole of the planetary arm 700 and the shaft hole of the planetary gear 701 to restrict the orbital movement of the planetary arm 700. Note that in the middle position of the conventional structure, no power is transmitted to allow the planetary arm 700 to orbit. In the conventional structure, the movement from the middle position to the orbital position (see FIG. Figure 7C ) movement allows the first fixed shaft 702 to be removed from the shaft hole of the planetary arm 700 and the shaft hole of the planetary gear 701, and the planetary arm 700 can revolve. In the revolving position of the conventional structure, the power that allows the planetary arm 700 to revolve is transmitted.

[0047] On the other hand, in the present embodiment, at positions other than the first position and the second position (except for the area from the first position to the second position), the first fixed shaft 6111 is removed from the shaft hole of the planetary arm 634 and the shaft hole of the planetary gear 633, and the revolution of the planetary arm 634 is not restricted. That is, in the present embodiment, in the path where the planetary gear returns from the second position to the first position without revolving, there is a third position (revolution position) where the first fixed shaft is removed from the shaft hole of the planetary arm 634 and the shaft hole of the introduction member 636. Therefore, in the path returning from the second position to the first position, it is not necessary to move the planetary gear 633 in the +X direction from the third position to move the shaft hole of the planetary arm 634 and the shaft hole of the planetary gear 633 away from the first fixed shaft 6111 as in the conventional structure. Therefore, according to the structure of the present embodiment, the device can be miniaturized by Fig.7D The arrows shown in indicate the amount.

[0048] In the conventional configuration, between the intermediate position and the revolving position, an operation of removing the fixed shaft 702 from the shaft hole of the planetary arm 700 and the shaft hole of the planetary gear 701 and an operation of meshing the gears to transmit the power for the revolving of the planetary arm 700 are performed. The operation sequence is: after the gears are meshed with each other, the fixed shaft 702 is removed from the shaft hole. In this process, since the planetary arm 700 can revolve after the gears are meshed with each other, it is possible that the planetary arm 700 revolves by the amount of one tooth of the gear at the moment of the gear meshing. In the case where the position of the planetary arm 700 is displaced due to the revolving, it is possible that the fixed shaft 702 cannot be inserted into the shaft hole of the planetary arm 700 and the shaft hole of the planetary gear 701 when returning to the first position. Therefore, before the gears are meshed with each other, the shaft hole of the planetary arm 700 and the shaft hole of the planetary gear 701 are fixed by the fixed shaft 702 to prevent the planetary arm 700 from unintentionally revolving when the gears are meshed with each other.

[0049] Therefore, the present embodiment has a structure that suppresses the fixing shaft 6111 from failing to be inserted into the shaft hole of the planetary arm 634 and the shaft hole of the planetary gear 633 when returning from the second position to the first position. Hereinafter, in the present embodiment, a structure that suppresses the fixing shaft 6111 from failing to be inserted into the shaft hole of the planetary arm 634 and the shaft hole of the planetary gear 633 when returning from the second position to the first position is described.

[0050] Fig. 8A 2 is a perspective view showing the vicinity of the sun gear 632 and the planetary gear 633 in this embodiment. Figure 8B is its cross-sectional view. In addition, Figure 8C is a cross-sectional view of the introduction member 636, Fig.8D The axis hole 6341 of the planetary arm 634 (see Fig. 8A) is a front view of the drive switching unit in a state where the drive switching unit is not coaxial with the fixed shaft 6111. The sun gear 632, the planetary gear 633 and the introduction member 636 are assembled to the planetary arm 634. Fig. 8A As shown, the flange 6321 prevents the sun gear 632 from being removed from the planetary arm 634 in the x direction. In addition, a structure is also applied that prevents removal in the -x direction and thereby prevents the components from being separated from the planetary arm 634 by fitting between the groove 6362 provided to the introduction member 636 and the hook 6342 of the planetary arm.

[0051] The planetary gear 633 is assembled to the planetary arm 634, and transmits the drive to each drive unit by receiving the transmission of the drive from the sun gear 632. In addition, in order to insert the fixed shaft 6111, shaft holes 6341 are respectively provided in the planetary arms 634 (see Fig. 8A ), an axial hole 6361 is provided in the introduction member 636 (see Figure 8C ). The introduction member 636 is assembled to the planetary arm 634, and the shaft hole 6341 and the shaft hole 6361 are formed to be substantially coaxial.

[0052] like Figure 8C As shown, an introduction surface 6363 having an inclined shape (inclined portion) that narrows along the insertion direction of the fixed shaft 6111 is provided to the introduction member 636. Thus, even in a case where the drive switching unit is inserted into a different fixed shaft and the shaft hole 6361 of the introduction member 636 is not coaxial with the fixed shaft, the drive switching unit can be rotated by using the inclined portion of the introduction surface 6363, thereby inserting the fixed shaft into the shaft hole 6361. In addition, the diameter of the contour portion 6364 of the introduction member 636 is formed to be smaller than the diameter of the tooth bottom circle of the planetary gear 633. With this structure, when the drive switching unit moves from the orbital position (third position) to the first position, the introduction member 636 does not interfere with the meshing between the planetary gear 633 and the drive input gear. In addition, the introduction member 636 includes a notch portion 6365 (see Fig.8D The notch portion 6365 is formed to prevent interference between the drive input gear and the introduction member 636 during the process of inserting the fixed shaft into the shaft hole 6361 by using the inclined portion of the introduction surface 6363 .

[0053] 9A to 9C is a diagram illustrating a drive switching unit inserted into a fixed shaft. Figures 9A to 9C A system is described in which a predetermined fixed shaft is introduced and inserted even when the fixed shaft is displaced from the shaft hole 6361 of the introduction member 636 due to irregular pivoting of the drive switching unit. Fig. 9A 63 is a diagram illustrating a front view in a state where the fixed shaft is offset from the shaft hole 6341 of the planetary arm 634, Fig. 9B is a side cross-sectional view, Fig. 9C 63 is a partially enlarged cross-sectional view illustrating a state in which the introduction surface 6363 and the first fixed shaft 6111 are in contact with each other.

[0054] In the present embodiment, when the drive switching unit is moved to the third position by the slide 41, the drive switching unit is removed from the fixed shaft, whereby during the movement to the third position, the planetary arm 634 is likely to revolve (swing) due to the contact between the components or the meshing of the gears with each other. The swing component may include the torsion of the components due to the deadweight of the components or the transmission of the drive, the meshing between the gears, etc., and the interval change of the assembly clearance amount between the components of the drive switching unit. Then, the planetary arm 634 pivots around the drive shaft 635, and the planetary arm 634, the shaft hole 6341 and the fixed shaft become non-coaxial. As a result, the planetary arm 634 may be brought to the fixed shaft when returning to the first position, or the unintentional fixed shaft may be inserted into the shaft hole of the planetary arm 634 by the next drive operation, and the operation may fail.

[0055] In the present embodiment, the introduction surface 6363 of the introduction member 636 and the ends of each fixed shaft have a slope shape, and are a structure that allows insertion even when the center of the shaft hole of the introduction member 636 and the center of the shaft hole of the planetary arm 634 are offset from the center of the fixed shaft. In the planetary gear 633, the introduction surface 6363 has an inclined portion within a range from a radius r1 to a radius r2 with the drive shaft 635 as the center. The radius r1 is a distance obtained by subtracting the radius of the fixed shaft, component tolerance, and allowance from the distance between the center of the drive shaft 635 and the center of the fixed shaft. On the other hand, the radius r2 is a distance obtained by adding the radius of the fixed shaft, component tolerance, and allowance to the distance between the center of the drive shaft 635 and the center of the fixed shaft.

[0056] Therefore, even when the shaft hole 6361 of the introduction member 636 is not coaxial with the fixed shaft, the drive switching unit rotates along the introduction surface 6363 , thereby inserting the fixed shaft 6111 into the shaft hole 6361 .

[0057] The angle (introduction angle α) at ​​which the fixed shaft 6111 can be introduced into the shaft hole 6361 of the introduction member 636 is determined by the following two elements. The first element is the angle a1 formed between the line connecting the axis center of the drive shaft 635 and the center of the shaft hole 6361 of the introduction member 636 and the line from the center axis of the drive shaft 635 to the outermost circle of the introduction surface 6363 of the introduction member 636. The second element is the angle a2 formed between the line connecting the axis center of the drive shaft 635 and the axis center of the fixed shaft and the line placed to contact the circle at the axis center of the drive shaft 635 and the end position of the fixed shaft 6111. That is, since a flat portion is formed at the end of the fixed shaft, the introduction angle α in the present embodiment is α=a1-a2.

[0058] When the change amount due to the swing of the planetary arm 634 and the assembly clearance (backlash) between the components is less than α, the fixed shaft 6111 is inserted into the drive switching unit through the introduction member 636. Fig. 9B In the case of retreat, the drive switching unit starts to move in the -x direction through the trigger holder spring 642. In this process, when the center of the shaft hole 6361 of the introduction member 636 is offset from the center of the fixed shaft 6111, as shown in FIG. Fig. 9C As shown, the tip of the fixed shaft 6111 contacts the introduction surface 6363. In this process, the load of the trigger holder spring 642 and the slope angle of the introduction surface 6363 are set so that the component Fa in the introduction surface direction of the fixed shaft 6111 inserted into the drive switching unit is greater than the friction force Fb that interferes with the insertion of the fixed shaft 6111 into the introduction surface 6363. Thus, the fixed shaft 6111 is inserted into the drive switching unit.

[0059] FIG. 10A to FIG. 10C It is a perspective view illustrating a portion causing the swing in each member. Fig. 10A The drive shaft 635 and the drive shaft gear 643 are shown. Fig. 10B The trigger holder 641 is shown. Fig. 10C A coupling member 637 is illustrated.

[0060] like Fig. 10A As shown, the comb-tooth portion 6431 is provided to the drive shaft gear 643 that rotates integrally with the drive shaft 635, and the comb-tooth portion 6372 that meshes with the comb-tooth portion 6431 and the comb-tooth portion 6371 that meshes with the comb-tooth portion 6343 of the planetary arm 634 are provided to the connecting member 637. The planetary arm 634 revolves integrally with the drive shaft 635 through the corresponding comb-tooth portions meshing with each other at the third position.

[0061] Here, the swing component generated in the interval between the comb-tooth portion 6343 of the planetary arm 634 and the comb-tooth portion 6371 of the coupling member 637 is b1, and the swing component generated in the interval between the comb-tooth portion 6372 of the coupling member 637 and the comb-tooth portion 6431 of the drive shaft gear 643 is b2. Swings may be generated in the swing component b1 and the swing component b2.

[0062] In addition, if Fig. 10B As shown, swing may be generated in the swing component b3 which is the interval between the locking unit 6412 of the trigger holder 641 and the drive cover 612 .

[0063] In addition, if Fig. 10CAs shown, the terminal corner of the comb tooth portion 6372 of the connecting member 637 and the terminal corner of the comb tooth portion 6431 of the drive shaft gear 643 have a bevel shape. When the comb tooth portions are in contact with each other, the bevel shape increases the contact area, thereby releasing stress and suppressing wear of other parts. However, when the comb tooth portions are in contact with each other at the bevel portion, the angle of the bevel may become the swing component b4 and cause the swing of the planetary arm 634.

[0064] Fig.11 It's a picture. FIG. 10A to FIG. 10C The table of the list of swing components b1 to b4 shown in FIG. When the swing angle of the planetary arm 634 obtained from the sum of the swing components β=b1+b2+b3+b4 is less than Fig. 9A In the case of the introduction angle α described in , the planetary arm 634 can be appropriately introduced. Therefore, in the present embodiment, each component is formed in such a way that the introduction angle α> the swing angle of the planetary arm 634 obtained from the swing component β. In addition, the above-mentioned introduction angle α and the swing component β are used for the construction of the components in the present embodiment, and are not limited to this. In the case of another construction, it is expected that calculations are performed as needed. The swing angle of the planetary arm 634 obtained from the sum of the swing components β=b1+b2+b3+b4 can also be said to be an angle obtained from the gap in the gear from the drive shaft 635 to the sun gear 632.

[0065] In the present embodiment, the image printing apparatus is described; however, the present invention can be applied to the drive switching mechanism of the present embodiment, an apparatus including the drive switching mechanism, and the like.

[0066] Thus, in the drive switching operation, except in the first position and the second position, the position of the planetary gear 633 is not fixed by the fixed shaft 6111. Therefore, a drive switching mechanism and an image printing apparatus that can miniaturize the apparatus can be provided.

[0067] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A drive switching mechanism, comprising: a drive shaft that is rotated by a drive source; A driven unit including a fixed shaft, the driven unit being transmitted with a driving force of the driving shaft; a drive switching unit that switches the transmission of the driving force of the driving shaft to the driven unit by moving in the thrust direction of the driving shaft; and a planetary gear provided to the drive switching unit, capable of orbiting around the drive shaft when not engaged with the fixed shaft, and capable of transmitting the driving force of the drive shaft to the driven unit when engaged with the fixed shaft, wherein The drive switching unit is capable of moving to: a first position where the driving force of the drive shaft is transmitted to the driven unit when engaged with the fixed shaft, a second position where the driving force of the drive shaft is not transmitted to the driven unit when engaged with the fixed shaft, and a third position where the planetary gear can orbit when not engaged with the fixed shaft, and When moving from the second position to the first position, the drive switching unit passes through the third position without allowing the planetary gear to orbit.

2. The drive switching mechanism according to claim 1, further comprising: a sun gear disposed on the same axis as the drive shaft and rotating integrally with the drive shaft; and A planet arm holds the planet gear in a manner that allows the planet gear to revolve around the sun gear.

3. The drive switching mechanism according to claim 1, comprising: A plurality of said driven units.

4. The drive switching mechanism according to claim 2, wherein: The planetary gear includes a shaft hole into which the fixed shaft can be inserted, and the shaft hole includes an inclined portion narrowed in an insertion direction of the fixed shaft.

5. The drive switching mechanism according to claim 4, wherein: The planetary gear includes an introduction member, and the inclined portion is provided to the introduction member.

6. The drive switching mechanism according to claim 4, wherein: An angle between the inclined portion and the central axis of the fixed shaft is greater than an angle at which the planetary arm swings due to a gap in a gear from the drive shaft to the sun gear.

7. The drive switching mechanism according to claim 1, wherein: The drive switching unit moves by the movement of the carriage.

8. The drive switching mechanism according to claim 7, wherein: As the carriage moves, the drive switching unit starts to move via a spring.

9. An image printing device, comprising: Driving source; a carriage that moves with the print head mounted thereon; a drive shaft that is rotated by the drive source; A driven unit including a fixed shaft, the driven unit being transmitted with a driving force of the driving shaft; a drive switching unit that switches transmission of the driving force of the driving shaft to the driven unit by moving in a thrust direction of the driving shaft as the carriage moves; and a planetary gear provided to the drive switching unit, capable of orbiting around the drive shaft when not engaged with the fixed shaft, and transmitting the driving force of the drive shaft to the driven unit when engaged with the fixed shaft, wherein The drive switching unit is capable of moving to: a first position in which the driving force of the drive shaft is transmitted to the driven unit when engaged with the fixed shaft, a second position in which the driving force of the drive shaft is not transmitted to the driven unit when engaged with the fixed shaft, and a third position in which the planetary gear can orbit when not engaged with the fixed shaft, and When moving from the second position to the first position, the drive switching unit passes through the third position without allowing the planetary gear to orbit.

10. The image printing device according to claim 9, wherein: The driving shaft is a conveying roller for conveying the printing medium, and The driven unit is a plurality of driven units including a feeding unit that feeds the printing medium to a position where the print head can perform printing and a maintenance unit that performs maintenance of the print head.

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