JP2009287660A - Drive transmission, sheet feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive transmission, a sheet feeder, and an image forming device, preventing a shaft coupling from being damaged even when a force in a direction to rotate a drive shaft is applied to a driven shaft. <P>SOLUTION: A drive shaft side shaft coupling part 71A provided to the drive shaft 71 is engaged with a driven shaft side shaft coupling part 73A provided to the driven shaft 73 by an urging member for urging at least one of the drive shaft 71 and the driven shaft 73. The drive shaft side shaft coupling part 71A and the driven shaft side shaft coupling part 73 are shaped so that when a force for rotating in one direction is applied to the driven shaft 73 and the driven shaft 73 is relatively rotated with respect to the drive shaft 71, the driven shaft 73 moves in the direction to release the engagement with the drive shaft 71 while resisting the urging force of the urging member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive transmission device, a sheet feeding device, and an image forming apparatus, and more particularly to a configuration of a drive transmission unit that transmits driving of a driving unit to a sheet feeding roller that feeds a sheet.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a printer or a facsimile, a sheet feeding cassette is mounted on the apparatus body, and when an image is formed, a sheet stored in the sheet feeding cassette is fed to an image forming unit by a sheet feeding roller. Some include a sheet feeding device for feeding (see Patent Document 1).

  For example, FIG. 8 shows an example of such a conventional sheet feeding device. In this sheet feeding device, the sheet feeding roller 3 has a substantially half-moon shape having an arc portion and a straight portion. Is used. The sheet feeding roller 3 having a substantially half-moon shape is controlled to rotate once counterclockwise during sheet feeding, and feeds the sheet S by frictional force.

  In this sheet feeding device, the paper feed tray 1 is detachably disposed on the main body (not shown), and when the sheet S is supplied to the paper feed tray 1, the direction of the paper feed tray 1 is indicated by an arrow A. The sheet S is replenished while being pulled out.

  The sheet feeding tray 1 is provided with an intermediate plate 50 that is pivotable in the vertical direction and is urged toward the sheet feeding roller 3 by a spring 51 with a predetermined pressure. When replenishing, the sheet S is stacked on the intermediate plate 50.

  In FIG. 8, 2 is a separation pad having a higher coefficient of friction than the sheet. The separation pad 2 is rotatably supported at the downstream end of the sheet feeding tray 1 in the sheet feeding direction, and is urged toward the sheet feeding roller 3 by a spring 20 with a predetermined pressing force. Is pasted. At the time of standby, the sheet feeding roller 3 is held at a position not in contact with the separation pad 2 as shown in FIG. 8A, but when the sheet feeding roller 3 rotates, As shown in FIG. 8B, a sandwiching portion (hereinafter referred to as a nip portion) is formed.

  In the sheet feeding apparatus having such a configuration, when feeding a sheet, the sheet feeding roller 3 rotates once in the arrow B direction from the state shown in FIG. As a result, a plurality of sheets S stacked on the sheet feeding tray 1 and urged by the intermediate plate 50 toward the sheet feeding roller 3 with a predetermined pressure applied to the leading end thereof are rubbed against the sheet feeding roller 3. The sheet is fed toward the nip portion between the separation pad 2 and the sheet feeding roller 3 by force.

  At this time, a plurality of sheets S may be sent toward the nip portion between the separation pad 2 and the sheet feeding roller 3 due to the frictional force between the sheets. In this case, the second and subsequent sheets are the sheets. It is stopped at the nip portion between the feed roller 3 and the separation pad 2. As a result, only the uppermost sheet S 1 which is in contact with the sheet feeding roller 3 having a higher friction coefficient than the separation pad 2 and is given a strong conveying force is fed to the conveying roller 4. Note that after one rotation and feeding of the sheet to the conveying roller 4, the sheet feeding roller 3 stops at the standby position shown in FIG. 8A, and the sheet S1 is conveyed into the apparatus by the conveying roller 4. Go.

  FIG. 9 shows a configuration of a conventional drive transmission device that transmits a driving force from a driving source (not shown) to the sheet feeding roller 3 to drive the sheet feeding roller 3. In FIG. 9, reference numeral 40 denotes an input gear that is rotated by driving from a drive source (not shown), 41 denotes a drive shaft to which the input gear 40 is fixed, and 31 denotes a drive shaft 41 that can be engaged via a shaft coupling 42. The driven shaft to which the sheet feeding roller 3 is fixed.

  When the sheet S is fed and the input gear 40 is rotated by the driving force from the driving source, the rotation of the input gear 40 is transmitted to the driven shaft 31 via the driving shaft 41, the shaft coupling 42 and the driving shaft 41. As a result, the sheet feeding roller 3 rotates.

JP 2007-31034 A

  By the way, in the sheet feeding apparatus provided with the conventional drive transmission device having such a configuration, before the rear end of the sheet S1 is separated from the nip portion formed by the sheet feeding roller 3 and the separation pad 2, the paper is fed. Troubles such as clogging may occur. In this case, the operator performs a process of pulling out the sheet S1 in the sheet conveyance direction.

  At this time, since a considerable sheet feeding pressure is applied between the sheet S1 and the sheet feeding roller 3, the sheet feeding roller 3 is moved by the frictional force between the sheet S1 and the sheet feeding roller 3. Try to rotate in the sheet feeding direction. That is, a force is applied to the driven shaft 31 in the direction in which the drive shaft 41 is rotated.

  At this time, the drive source that transmits the rotational force to the driven shaft 31 and the sheet feeding roller 3 via the drive shaft 41 is in a stopped state. For this reason, when a force is applied to the driven shaft 31 in the direction in which the drive shaft 41 is rotated, a large load acts on the shaft coupling 42 and the shaft coupling 42 may be damaged.

  Therefore, the present invention has been made in view of such a current situation, and even when a force is applied to the driven shaft in the direction of rotating the drive shaft, the drive transmission device capable of preventing the shaft joint from being damaged and An object of the present invention is to provide a sheet feeding apparatus.

  The present invention provides a drive transmission device in which a drive shaft and a driven shaft are engagable and transmit a rotational drive in one direction of the drive shaft to the driven shaft. A shaft coupling portion, a driven shaft side shaft coupling portion provided on the driven shaft, and urging at least one of the driving shaft and the driven shaft, the driving shaft side shaft coupling portion and the driven shaft An urging member that engages with the side shaft joint portion, and when the drive shaft rotates in one direction, the shape of the drive shaft side shaft joint portion and the driven shaft side shaft joint portion is When the driven shaft is in a predetermined rotational position, the driven shaft is engaged with the driving shaft so that rotation is transmitted, and the driven shaft is applied with a force that is rotated in the one direction. When the shaft rotates relative to the drive shaft, it resists the biasing force of the biasing member. Serial is characterized in that it has a shape in which the engagement between the drive shaft and the driven shaft is released.

  In the present invention, when the driven shaft is rotated by applying a force that rotates the driven shaft side shaft joint portion and the driven shaft side shaft joint portion in one direction to the driven shaft, the driven shaft and the driving shaft The shape is such that the engagement is released. Thereby, even when a force is applied to the driven shaft in the direction of rotating the drive shaft, the shaft coupling can be prevented from being damaged.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an example of an image forming apparatus provided with a sheet feeding apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a laser beam printer, and 1A denotes a laser beam printer main body (hereinafter referred to as a printer main body). The laser beam printer 1 fixes an image forming unit 1B, a sheet feeding device 1C that feeds the sheet S to the image forming unit 1B, and a toner image transferred onto the sheet S by the transfer unit 1D. A fixing unit 13 and the like are provided.

  Here, the image forming unit 1B includes a process cartridge 6 including a photosensitive drum 6a, a charging roller 6b, a developing sleeve 6c, a cleaning blade 6e, and a toner container 6d in a detachable manner. Also provided is a laser exposure device 7 that exposes the surface of the photosensitive drum 6a to form an electrostatic latent image on the photosensitive drum.

  The charging roller 6b is a charging unit that uniformly charges the surface of the photosensitive drum 6a, and the developing roller 6c is a toner image that attaches toner to the electrostatic latent image formed by the laser exposure device 7. Developing means for forming an image. The cleaning blade 6e removes the toner remaining on the surface of the photosensitive drum 6a after the toner image is transferred, and stores it in a waste toner container 6f.

  The sheet feeding device 1C is provided below the printer main body 1A, and the sheet feeding cassette 60 that is detachably attached to the printer main body 1A that also serves as the sheet feeding device main body, and the sheet S on the paper feeding cassette one by one. A half-moon shaped sheet feeding roller 9 for feeding is provided.

  Note that the sheet feeding roller 9 as the sheet feeding member is controlled to rotate counterclockwise only during feeding, and feeds the contacted sheet S by frictional force. Further, the sheet feeding cassette 60 that is a sheet storage unit is provided so as to be pivoted in the vertical direction. I have.

  The transfer unit 1D forms a transfer nip by pressing against the photosensitive drum 6a and the photosensitive drum 6a, and transfers the toner image on the photosensitive drum to the sheet S when the sheet S passes through the transfer nip. The transfer roller 8 is used.

  Next, an image forming operation in the laser beam printer 1 configured as described above will be described.

  When the image forming operation is started, first, the photosensitive drum 6a rotates in the direction of arrow A, and is uniformly charged to a predetermined polarity and a predetermined potential by a charging roller 6b fed from a high voltage power source (not shown). The photosensitive drum 6a whose surface has been charged is irradiated with laser light L emitted from the laser exposure device 7 based on the image information and reflected by the reflecting mirror 7a. An electrostatic latent image is formed.

  Next, the electrostatic latent image is filled in the toner container 6d as the developing roller 6c rotates, and the toner that has been appropriately charged is supplied onto the photosensitive drum 6a and adheres to the electrostatic latent image. By doing so, it is developed and visualized as a toner image.

  On the other hand, in parallel with such a toner image forming operation, the sheets S stacked and stored in the sheet feeding cassette 60 are fed from the sheet feeding roller 9 at a predetermined timing. Note that the sheet feeding roller 9 holds a position where it does not come into contact with the separation pad 61 as a separation member as shown in FIG.

  When the image forming operation is started, the sheet feeding roller 9 rotates once in the arrow direction shown in FIG. At this time, the sheets S stacked on the sheet feeding tray 60 are urged by the intermediate plate 64 toward the sheet feeding roller 9 with a predetermined pressure. Further, the separation pad 61 is biased by a spring 68 toward the sheet feeding roller 9.

  Thereafter, the sheet S fed along with the rotation of the sheet feeding roller 9 is conveyed between the separation pad 61 and the sheet feeding roller 9. Here, the friction coefficient, contact angle, and shape of the surface of the separation pad 61 that is the sheet separation means are set so as to send out only the uppermost sheet S1 for each sheet feeding operation.

  Thereby, when the sheets S are overlapped and fed, the conveyance of the sheet S on the separation pad side is suppressed by the separation pad 61, and only the sheet S1 on the sheet feeding roller side is conveyed. As a result, the sheets S stacked and stored in the sheet feeding cassette 60 are conveyed one by one through the conveying roller pair 11a and 12a to the registration roller pair 11b and 12b without being overlapped and conveyed. Note that the sheets other than the uppermost sheet S1 are not fed into the image forming apparatus main body by the separation pad 61. Further, after the sheet S1 is sent to the pair of conveying rollers 11a and 12a, the sheet feeding roller 9 stops at the standby position shown in FIG.

  Next, the skew of the sheet S1 conveyed to the registration roller pairs 11b and 12b is corrected in the registration roller pairs 11b and 12b. Thereafter, the pair of registration rollers 11b and 12b are conveyed to the transfer unit 1D at a timing so that the leading edge of the sheet S1 coincides with the leading edge of the toner image formed on the surface of the photosensitive drum 6a. Then, the toner image on the surface of the photosensitive drum 6a is transferred by the transfer roller 8 to the sheet S1 thus conveyed to the transfer unit 1D.

  The untransferred toner remaining on the photosensitive drum 6a without being transferred is stored in the waste toner container 6f by the cleaning blade 6e. The photosensitive drum 6a whose surface has been cleaned repeatedly enters the next image forming process.

  Next, the sheet S1 to which the toner image is transferred is conveyed to the fixing unit 13, and the toner image is fixed to the sheet S1 in the fixing unit 13. Thereafter, the sheet S1 on which the toner image is fixed is conveyed to the discharge roller pair 14c, 15c by the conveyance roller pair 14a, 15a and the conveyance roller pair 14b, 15b disposed in the sheet conveyance downstream portion of the fixing unit 13. The Thereafter, the paper is discharged onto a paper discharge tray 16 provided on the upper portion of the printer main body 1A by a pair of paper discharge rollers 14c and 15c.

  FIG. 3 shows a drive transmission device 70 </ b> A provided in the sheet feeding apparatus according to the present embodiment, which transmits a driving force from a driving source (not shown) to the sheet feeding roller 3 to drive the sheet feeding roller 3. It is a figure which shows schematic structure. In FIG. 3A, 71 is a drive shaft, 70 is an input gear that receives a rotational force from a drive source (not shown), and the drive shaft 71 is engaged with the input gear 70 so as to rotate in phase. .

  Reference numeral 73 denotes a driven shaft engaged with the sheet feeding roller 9 so as to rotate in the same phase, and this driven shaft 73 is a compression provided inside the sheet feeding roller as shown in FIG. The spring 74 is engaged with the drive shaft 71 by receiving a pressing force in the direction of engagement with the drive shaft 71. The compression spring 74 as an urging member for engaging the driven shaft 73 and the driving shaft 71 in this way may be provided on at least one of the driven shaft side and the driving shaft side.

  Here, the drive shaft 71 and the driven shaft 73 urged by the compression spring 74 are provided on the drive shaft-side shaft coupling portion 71A provided on the drive shaft 71 and the driven shaft 73 as shown in FIG. The driven shaft side shaft coupling portion 73 </ b> A is provided so as to be engageable via a shaft coupling 72.

  The drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A have flat surfaces 75 and 76 that are parallel to the axial direction, respectively. When a driving force (rotational drive) in one direction is transmitted from a drive source (not shown) to the input gear 70 and the drive shaft 71 rotates, the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A Flat surfaces 75 and 76 parallel to the axial direction abut. Accordingly, the driving force in one direction from the driving source is transmitted to the driven shaft 73 at a predetermined rotational position without changing the direction, and the sheet feeding roller 9 rotates in phase with the driven shaft 73.

  By the rotation of the sheet feeding roller 9, the sheet S 1 in contact with the surface of the sheet feeding roller 9 is fed out as described above, and is at the nip portion formed by the sheet feeding roller 9 and the separation pad 61. After being separated into one sheet, it is sent to the transport rollers 11a and 12a.

  On the other hand, for example, when the sheet is jammed in a state where the rear end of the sheet is sandwiched between the nip portion formed by the sheet feeding roller 9 and the separation pad 61, the sheet is pulled out in the sheet feeding direction.

  At this time, since a considerable sheet feeding pressure is applied between the sheet S1 and the sheet feeding roller 9, the sheet feeding roller 9 is moved by the frictional force between the sheet S1 and the sheet feeding roller 9. Try to rotate in the feeding direction. That is, when the sheet is pulled out in the sheet feeding direction, a force is applied to the driven shaft 73 in the direction in which the driving shaft 71 is rotated in one direction for rotating the sheet feeding roller 9.

  In this case, the driven shaft 73 rotates relative to the drive shaft 71 in one direction, and the inclined surface 77 has an angle in the axial direction of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A. 78 abuts. The same applies to the case where a force T that rotates the drive shaft 71 in the direction opposite to the sheet feeding direction is applied to the driven shaft 73.

  And when the inclined surfaces 77 and 78 which have an angle contact | abut in the axial direction of the drive shaft side shaft coupling part 71A and the driven shaft side shaft coupling part 73A in this way, the axial direction of the rotational force which acts on the inclined surfaces 77 and 78 The component force B presses the driven shaft 73 in a direction away from the driving shaft 71. Here, when the axial component B of the rotational force becomes larger than the pressing force (biasing force) by the compression spring 74 shown in FIG. 3B provided in the sheet feeding roller 9, the driven shaft 73 is driven. Moves in a direction to release the engagement with the drive shaft 71.

  Along with this, the pressure contact engagement between the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A by the compression spring 74 is released, and the engagement with the drive shaft 71 is released. As described above, when the driven shaft 73 rotates when the jammed sheet is pulled out, the engagement between the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A is released. Moves in a direction away from the drive shaft 71.

  Here, in order to move the driven shaft 73 when the driven shaft 73 rotates, the central portion of the drive shaft side shaft coupling portion 71A has two different diameters as shown in FIGS. 5 (a) and 5 (b). The convex part 80 comprised by the substantially cylindrical shape 80a, 80b which consists of two (plural) concentric cylinder surfaces is provided. Further, at the center of the driven shaft side shaft coupling portion 73A, as shown in FIGS. 5C and 5D, two different diameters for engaging with the convex portion 80 of the driving shaft side shaft coupling portion 71A are provided. A concave portion 81 is provided that is constituted by substantially cylindrical grooves 81a and 81b having two (plural) concentric cylindrical surfaces.

  Here, the relationship between the diameters R1 and R2 of the substantially cylindrical shapes 80a and 80b of the drive shaft side shaft coupling portion 71A and the diameters R1 ′ and R2 ′ of the substantially cylindrical grooves 81a and 81b of the driven shaft side shaft coupling portion 73A. Are configured such that R1> R2, R1 ′> R2 ′, R1 <R1 ′, R2 <R2 ′.

  And when comprised in this way, once engagement with the drive shaft side shaft coupling part 71A and the driven shaft side shaft coupling part 73A is once released | released, until the driven shaft 73 rotates 360 degrees, the drive shaft side The shaft coupling portion 71A and the driven shaft side shaft coupling portion 73A are not engaged. When the driven shaft 73 rotates in such a disengaged state, the distal end of the outer peripheral portion of the concave portion 81 of the driven shaft side shaft coupling portion 73A is the distal end of the outer peripheral portion of the convex portion 80 of the driving shaft side shaft joint portion 71A. The driven shaft 73 is idled without being engaged with the drive shaft 71 while sliding. As a result, the driven shaft 73 maintains the disengaged state with the drive shaft 71.

  On the other hand, when the idling angle (rotational position) of the driven shaft 73 reaches 360 °, the angle phases of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A coincide with each other. The driving shaft side shaft coupling portion 71A and the driven shaft side shaft coupling portion 73A are again engaged. The above operation is repeated until the trailing edge of the sheet passes through the nip between the sheet feeding roller 9 and the separation pad 61, whereby the drive shaft side shaft joint portion 71A, the driven shaft side shaft joint portion 73A and the input gear are The jammed sheet can be removed without causing damage such as 70.

  When the sheet is removed before the angle phases of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A coincide with each other, the driven shaft 73 stops at that position. However, even when stopped at such a position, the driven shaft 73 is rotated by the biasing force of the compression spring 74 so that the driven shaft side shaft joint portion 73A engages with the drive shaft side shaft joint portion 71A. Even when the driven shaft 73 does not rotate, when the sheet feeding operation is resumed thereafter, the drive shaft 71 starts to rotate. Accordingly, the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint are eventually used. The portion 73A is engaged.

  Thus, in the present embodiment, when the shape of the drive shaft side and driven shaft side shaft coupling portions 71A, 73A is rotated relative to the drive shaft 71, the driven shaft 73 is driven. Is shaped so as to move in the direction of releasing the engagement with the drive shaft 71. Further, when the rotated driven shaft 73 reaches a predetermined rotational position, the driven shaft 73 is configured to be engaged with the drive shaft 71 by the urging force of the compression spring 74.

  Thereby, even when a force is applied to the driven shaft 73 in the direction of rotating the drive shaft 71, the shaft coupling 72, the driven shaft 73, the drive shaft 71, and the like can be prevented from being damaged. Further, after the release, the drive shaft side shaft coupling portion 71A and the driven shaft side shaft coupling portion 73A can be returned to the engaged normal state without performing any special work.

  By the way, the case where the convex part comprised by two substantially cylindrical shapes from which the diameter (radius) in the direction orthogonal to an axial direction differs was provided in the center part of 71 A of drive shaft side shaft coupling parts until now was demonstrated. . Moreover, the case where the recessed part comprised from the substantially cylindrical shape from which the diameter of the direction orthogonal to an axial direction differs in the center part of the driven shaft side shaft coupling part 73A was demonstrated.

  However, the present invention is not limited to this. For example, as shown in FIGS. 6A and 6B, two (plural) half-diameters having the same center in the direction orthogonal to the axial direction are formed in the central portion of the drive shaft side shaft coupling portion 71A. You may make it form the convex part 90 comprised by substantially cylindrical shape 90a, 90b which consists of a cylindrical surface. Further, as shown in FIGS. 6C and 6D, two (plural) same diameters having different centers in the direction orthogonal to the axial direction are provided at the central portion of the driven shaft side shaft coupling portion 73A. You may make it form the recessed part 91 comprised by the substantially cylindrical groove | channels 91a and 91b which consist of this semi-cylindrical surface.

  In this case, the distances L1 and L2 from the shaft centers of the substantially cylindrical shapes 90a and 90b of the drive shaft side shaft coupling portion 71A and the shaft centers of the substantially cylindrical grooves 91a and 91b of the driven shaft side shaft coupling portion 73A. The distances L1 ′ and L2 ′ are configured such that L1> L2 and L1 ′> L2 ′. Further, L1 <L1 ′ and L2 <L2 ′ are satisfied.

  And when comprised in this way, once engagement with the drive shaft side shaft coupling part 71A and the driven shaft side shaft coupling part 73A is once released | released, until the driven shaft 73 rotates 360 degrees, the drive shaft side The shaft coupling portion 71A and the driven shaft side shaft coupling portion 73A are not engaged. When the driven shaft 73 rotates in such a disengaged state, the distal end of the outer peripheral portion of the concave portion 91 of the driven shaft side shaft coupling portion 73A is the distal end of the outer peripheral portion of the convex portion 90 of the driving shaft side shaft joint portion 71A. The driven shaft 73 is idled without being engaged with the drive shaft 71 while sliding. As a result, the driven shaft 73 maintains the disengaged state with the drive shaft 71.

  On the other hand, when the idling angle of the driven shaft 73 reaches 360 °, the angle phases of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A coincide, and the drive shaft side shaft joint portion 71A and the driven shaft again. The shaft side shaft joint portion 73A is engaged.

  Further, for example, as shown in FIGS. 7A and 7B, planes 111 and 112 parallel to the axial direction at the center of the drive shaft side shaft coupling portion 71A and a slope 113 having an angle in the axial direction. , 114 may be formed. Moreover, you may make it form the convex part 100a which has the planes 121 and 122 parallel to an axial direction in the center part of the driven shaft side axial coupling part 73A, and the slopes 123 and 124 which have an angle in an axial direction. .

  Here, the planes 111 and 112 of the drive shaft side shaft coupling portion 71A have different angles ∠C and ∠D with respect to the axial rotation direction, in other words, different angles formed with the center in the direction orthogonal to the axial direction. Are arranged as follows. Further, the planes 121 and 122 of the driven shaft side shaft coupling portion 73A are also arranged so as to have different angles C ′ and D ′ similarly to the driving shaft side. In this case, the relationship of the angles with respect to the axis rotation direction of the plane is such that ∠C> ∠D, ∠C '> ∠D', ∠C <∠C ', ∠D <∠D'. The

  Thus, in the disengaged state, the driven shaft is slid while rubbing the outer peripheral end of the convex portion 100a of the driving shaft side shaft coupling portion 71A and the outer peripheral portion tip of the concave portion 100b of the driven shaft side shaft coupling portion 73A. 73 and the drive shaft 71 run idle without being engaged, and maintain the disengaged state.

  On the other hand, when the idling angle of the driven shaft 73 reaches 360 °, the angle phases of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A coincide, and the drive shaft side shaft joint portion 71A and the driven shaft again. The shaft side shaft joint portion 73A is engaged.

  When the sheet feeding roller 9 is configured to feed a sheet by one rotation drive as in the present embodiment, the driving shaft side shaft coupling portion 71A and the driven shaft side shaft coupling portion 73A are again used. Are engaged when the driven shaft 73 is rotated 360 °. However, the present invention is not limited to this, and depending on the shape of the sheet feeding roller 9, the driving configuration, and the like, the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A are again engaged. May be at other angles.

  In the description so far, the case where the driven shaft 73 is urged by the compression spring 74 and the driven shaft 73 rotates and the driven shaft 73 moves against the compression spring 74 has been described. However, the present invention is not limited to this. For example, when the drive shaft 71 is urged by the urging member and the driven shaft 73 rotates, the drive shaft 71 can move in the direction in which the engagement with the driven shaft 73 is released while the drive shaft 71 resists the urging member. Also good. That is, at least one of the drive shaft and the driven shaft may be urged by the urging member.

  Further, in the description so far, the example in which the driving shaft side shaft coupling portion 71A is provided with a protruding portion protruding in the axial direction and the driven shaft side shaft coupling portion 73A is provided with a recess has been described. Not limited to this. For example, a convex portion protruding in the axial direction may be provided on the driven shaft side shaft coupling portion 73A, and a concave portion may be provided on the driving shaft side shaft coupling portion 71A. That is, a convex portion is provided on one of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A, and the other of the drive shaft side shaft joint portion 71A and the driven shaft side shaft joint portion 73A is a convex portion. What is necessary is just to provide the recessed part to engage.

1 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus including a sheet feeding device according to an embodiment of the present invention. The figure explaining the sheet feeding operation | movement of the said sheet feeding apparatus. FIG. 3 is a diagram illustrating a schematic configuration of a drive transmission device that is provided in the sheet feeding device and drives a sheet feeding roller. The figure which shows the engagement state of the drive shaft and driven shaft which comprise the said drive transmission part. The figure which shows the shape of the drive shaft side shaft coupling part provided in the said drive shaft, and the driven shaft side shaft coupling part provided in the driven shaft. The figure which shows the other shape of the drive shaft side shaft coupling part provided in the said drive shaft, and the driven shaft side shaft coupling part provided in the driven shaft. The figure which shows the other shape of the drive shaft side shaft coupling part provided in the said drive shaft, and the driven shaft side shaft coupling part provided in the driven shaft. The figure explaining the conventional sheet feeding apparatus. The figure which shows the structure of the drive transmission device provided in the said conventional sheet feeding apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam printer 1B Image formation part 1C Sheet feeding apparatus 9 Sheet feeding roller 61 Separation pad 70 Input gear 70A Drive transmission apparatus 71 Drive shaft 71A Drive shaft side shaft coupling part 72 Shaft coupling 73 Driven shaft 73A Driven shaft side Shaft coupling part 74 Compression spring 80 Convex part 80a, 80b Substantially cylindrical shape 81 Concave part 81a, 81b Substantially cylindrical groove 90 Convex part 90a, 90b Substantially cylindrical part 91 Concave part 91a, 91b Substantially cylindrical groove 100a Convex part 100b Concave part 111 , 112 Convex part plane 121, 122 Concave part plane 113, 114 Convex part slope 123, 124 Concave part slope

Claims (7)

In the drive transmission device, the drive shaft and the driven shaft are provided so as to be engageable, and the rotational drive in one direction of the drive shaft is transmitted to the driven shaft.
A drive shaft side shaft joint provided on the drive shaft;
A driven shaft side shaft joint provided on the driven shaft;
A biasing member that biases at least one of the drive shaft and the driven shaft and engages the drive shaft side shaft joint portion and the driven shaft side shaft joint portion;
The shapes of the drive shaft side shaft joint portion and the driven shaft side shaft joint portion are such that when the drive shaft rotates in one direction, the driven shaft is driven in the predetermined rotational position. When the driven shaft is rotated relative to the drive shaft by applying a force that is rotated in the one direction to the driven shaft, the rotation is transmitted to the shaft by engaging with the shaft. A drive transmission device characterized in that the engagement between the driven shaft and the drive shaft is released against the biasing force of the biasing member. One of the drive shaft side shaft joint portion and the driven shaft side shaft joint portion includes a convex portion protruding in the axial direction, and the other of the drive shaft side shaft joint portion and the driven shaft side shaft joint portion is A recess that engages with the protrusion,
The convex portion includes a plane parallel to the axial direction and an inclined surface having an angle with respect to the axial direction, and the concave portion is a plane with respect to the axial direction engaged with the plane of the convex portion, and A slope having an angle with respect to the axial direction engaged with the slope of the convex part,
The slope of the convex part and the slope of the concave part move in a direction in which the driven shaft is disengaged from the driving shaft when the driven shaft is rotated in the direction of rotating the driving shaft. The drive transmission device according to claim 1, wherein the drive transmission device has an angle.   The convex portion is configured by a plurality of substantially cylindrical shapes having different radii in a direction orthogonal to the axial direction, and the concave portion is configured by a plurality of substantially cylindrical grooves having different radii in the direction orthogonal to the axial direction. The drive transmission device according to claim 2, wherein the drive transmission device is provided.   The convex portion is configured by a plurality of substantially cylindrical shapes having different distances from the center in a direction orthogonal to the axial direction, and the concave portion is formed by a plurality of substantially cylindrical grooves having different centers orthogonal to the axial direction. The drive transmission device according to claim 2, wherein the drive transmission device is configured.   The convex portion includes a plurality of the planes having different angles with a center in a direction orthogonal to the axial direction, and the concave portion has the plurality of planes having different angles with a center orthogonal to the axial direction. The drive transmission device according to claim 2, wherein the drive transmission device is provided.   A sheet feeding member that feeds the sheet, and a separation member that contacts the sheet feeding member and separates the sheet, and the sheet feeding member is attached to the driven shaft, and is separated from the driving shaft. A sheet feeding device comprising the drive transmission device according to any one of claims 1 to 5, wherein rotational drive in a direction is transmitted to the driven shaft.   An image forming apparatus comprising: an image forming unit; and a sheet feeding device according to claim 6 for feeding a sheet to the image forming unit.

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