JP2006315822A - Automatic paper feeding device, recording device, and control method for automatic paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably make paper bite a carrying roller in simple constitution. <P>SOLUTION: This automatic paper feeding device comprises a sun gear 38, a first and a second planetary gears 39 and 45 to be engaged with the sun gear, a first planetary arm 40 connected to the sun gear and the first planetary gear, a second planetary arm 44 connected to the sun gear and the second planetary gear, a control gear 24 to be engaged with the first planetary gear as the first planetary arm rotates to transmit torque only in the rotation direction corresponding to the first rotation direction, a paper feed gear 19 to be engaged with the control gear, and also be engaged with the second planetary gear as the second planetary arm rotates, a regulation member 43 regulating the rotation of the first and second planetary arms, a feed roller driven by the feed gear, and the carrying roller 30 provided downstream of the feed roller in the paper feeding direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an automatic paper feeder that feeds paper from a paper stacking unit to a printing unit, a recording apparatus including the same, and a control method for the automatic paper feeder.

  Conventionally, an automatic paper feeding device including a planetary arm and a planetary gear, which uses the same drive source as the conveying roller as a driving source for driving the automatic paper feeding device, and switches the driving transmission method of the feeding roller, and the same are provided. There is a recording device. According to this automatic paper feeder, when the leading edge of the fed paper reaches the printing section, it is bitten by one end into the nip formed by the transport roller and the pinch roller facing it. Thereafter, the transport roller is reversed to discharge the paper once, thereby adjusting the traveling direction of the paper and performing a skew correction operation. FIG. 14 shows a schematic diagram of a skew correction operation in a conventional automatic paper feeder.

  As shown in FIG. 14A, the drive gear 135 connected to a drive source (not shown) directly drives the transport roller gear 136, and the driving force is two idle gears 138a and 138b, a sun gear 140, and It is transmitted to the paper feed gear 119 via the planetary gear 139. The paper feed gear 119 is attached to the feed roller 111, and the drive gear 135 is attached to the transport roller gear 136. The feed roller 111 and the paper feed gear 119, and the transport roller 130 and the transport roller gear 136 are shown in the same circle for easy understanding of the drawing. Is provided. The sun gear 140 and the planetary gear 139 are arm-supported by a planetary arm 141, and resistance is given to the planetary gear 139. A separation roller 112 is urged to the feeding roller 111.

  When the paper feeding operation is started, the drive source rotates in the P direction as shown in FIG. Then, the idle gears 138a and 138b and the sun gear 140 each rotate in the direction of the arrow in the figure. Since a rotational moment is generated in the planetary arm 141 in the Q direction, the planetary gear 139 is connected to the paper feed gear 119 and the feed roller 111 rotates in the R direction. As described above, the transport roller 130 rotates in the direction of transporting the paper in the forward direction, and the feed roller 111 connected to the paper feed gear 119 also rotates in the direction of transporting the paper to the printing unit. When the conveyance of the paper is continued, the leading edge of the paper reaches the nip portion formed by the conveyance roller 130 and the pinch roller 129 and is bitten.

  Here, as shown in FIG. 14C, when the conveying roller 130 is rotated in the reverse direction, the sheet is discharged from the nip portion in the upstream direction. At this time, the paper feed gear 119 is separated from the planetary gear 139 and the gear transmission is cut off. Since a one-turn clutch (not shown) is incorporated in the paper feed gear 119, the paper does not move at the nip portion between the separation roller 112 and the feed roller 111 even if the paper is reversed. A bend (loop) is formed on the sheet, and the leading edge of the sheet is pressed against the nip formed by the conveying roller 130 and the pinch roller 129 by the reaction force, and the end of the sheet is pressed between the conveying roller 130 and the pinch roller 129. It is possible to follow the nip part. With the above operation, even if the sheet has been transported obliquely, the traveling direction of the sheet can be corrected and the skew of the sheet can be prevented.

  As shown in FIG. 14D, the paper whose traveling direction is adjusted is sandwiched between the transport roller 130 and the pinch roller 129 and transported to the printing unit. At this time, since the drive gear 135 rotates in the P direction, a moment in the Q direction is generated in the planetary arm 141, and the planetary gear 139 is reconnected to the paper feed gear 119.

As described above, the automatic paper feeder of the prior art has the advantage that the switching of the driving force for the skew correction operation is realized by a simple mechanism and the automatic paper feeder can be easily controlled.
JP 2004-10266 A

  In the automatic paper feeder of the prior art, the nip abutting force when the paper is caught in the transport roller is generated only by the separation roller pressure. For this reason, when thick paper or slippery paper is fed, there is a problem that the urging force against the nip becomes insufficient, and it is not possible to stably secure the biting of the paper into the transport roller. In order to solve this problem, it is conceivable to increase the urging force of the separation roller 112 to the feeding roller 111. However, when the urging force is increased, when two or more sheets enter at the same time, the frictional force between the sheets also increases, so that the separation performance may be deteriorated. Therefore, there is a limit to increasing the paper holding force at the nip portion between the feeding roller 111 and the separation roller 112.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an automatic paper feeding device and a recording device that have a simple configuration and can stably feed paper into a transport roller. Another object of the present invention is to provide a method for controlling such an automatic paper feeder.

  The automatic paper feeder of the present invention is connected to the sun gear, the first and second planetary gears engaged with the sun gear, the sun gear and the first planetary gear, and the sun gear is in the first rotation direction. The first planetary gear is connected to the first planetary arm that rotates the first planetary gear around the sun gear in the first rotation direction, and to the sun gear and the second planetary gear. A second planetary arm that rotates the second planetary gear around the sun gear in the second rotational direction when rotated in the second rotational direction; and A control gear that engages with the planetary gear and transmits torque only in the rotation direction corresponding to the first rotation direction, and engages with the control gear and rotates the second planetary arm to thereby generate the second planetary gear. A paper feed gear that engages with each other, and a regulating member that regulates rotation of the first and second planetary arms, A feeding roller which is driven in the paper feed gear, in conjunction with the sun gear, and a conveyance roller than the feeding roller provided on the downstream side in the sheet conveyance direction.

  The control method of the automatic paper feeder of the present invention selectively executes the following first skew correction operation and second skew correction operation. In the first skew correction operation, the first planetary gear engaged with the sun gear rotates the sun gear in the first direction, and the first planetary gear connected to the sun gear and the first planetary gear. Rotating the arm in the first direction to rotate around the sun gear and engaging the first planetary gear with the control gear; and further rotating the sun gear in the first direction Rotating the paper feed gear engaged with the control gear and rotating the feed roller connected to the paper feed gear in the paper transport direction, and the fed paper being rotated The sheet is conveyed by a feeding roller, and is sandwiched between conveyance rollers located downstream of the feeding roller in the sheet conveying direction, and the rotation of the control gear is prevented by a one-way clutch means incorporated in the control gear. Is held by the feed roller, By rotating the feed roller in the paper conveyed backward direction, and a step causing backhaul was pinched by the conveying roller paper. The second skew correction operation includes the above-described engagement step, a feeding roller rotating step, a step of conveying the fed paper to the front of the conveying roller by the rotating feeding roller, After being transported to the front of the transport roller, the second planetary gear engaged with the sun gear rotates the sun gear in the second direction, and the second planetary gear connected to the sun gear and the second planetary gear. Rotating the planetary arm in the second direction to rotate around the sun gear and engaging the second planetary gear with the paper feed gear; and rotating the transport roller in the direction in which the paper is fed back And further rotating the sun gear in the second direction, rotating the feeding roller in the paper transport direction, and transporting the paper until it hits the transport roller.

  According to the present invention, since a plurality of conveyance modes can be realized, the sheet can be stably caught in the conveyance roller, and the recording quality can be improved. In addition, since the above effect can be obtained with a simple configuration without providing a complicated driving force switching mechanism, the cost can be reduced. Furthermore, since it can be configured with a small space, the automatic paper feeding device and the recording device can be reduced in size.

  Hereinafter, embodiments of an automatic sheet feeder, a recording apparatus, and an automatic sheet feeder control method according to the present invention will be specifically described with reference to the drawings. FIG. 1 is a schematic perspective view of a recording apparatus according to an embodiment of the present invention. FIG. 2 is a schematic top view of the recording apparatus shown in FIG. FIG. 3 is a schematic cross-sectional view taken along line AA in FIG. FIG. 4 is a schematic perspective view showing a drive transmission unit of an automatic paper feeder according to an embodiment of the present invention (FIGS. 4A and 4B are perspective views seen from different directions). . FIG. 5 is an exploded perspective view of a unit including a sun gear, a planetary gear meshing with the sun gear, and a planetary arm.

  The automatic paper feeder includes a paper stacking unit, a paper feeding / separating unit, a multifeed prevention unit, and a drive transmission unit that drives these units. In order to drive the automatic paper feeder, a separate drive source is required, but it is assumed that the automatic paper feeder is integrated with another device such as a recording device. The drive source is provided in a recording apparatus (hereinafter abbreviated as main body). However, the automatic paper feeder itself may be configured to include a drive source.

  First, the drive source will be described. As shown in FIG. 4, the drive source is composed of a conveying roller pulley 36, a drive pulley 35, and a belt 34 that connects them, and is provided in a portion of the recording apparatus opposite to the automatic paper feeder. . When the driving pulley 35 is driven, the driving force is transmitted to the conveying roller pulley 36 via the belt 34, and the driving force is transmitted to the conveying roller 30 connected to the conveying roller pulley 36.

  Next, the drive transmission unit will be described. 6A to 6D are explanatory diagrams illustrating the configuration and operation of the drive transmission unit. The main part of the drive transmission unit is composed of a gear train centered on the sun gear, and transmits the driving force from the drive source to the paper stacking unit, paper feed / separation unit, and multifeed prevention unit. The drive transmission unit includes a conveyance output gear 39 a provided at an end of the conveyance roller 30, an idle gear 37 engaged with the conveyance output gear 39 a, and a sun gear 38 engaged with the idle gear 37. The driving force transmitted from the drive transmission unit is transmitted from the transport output gear 39a to the sun gear 38 via the idle gear 37. A first planetary gear 39 and a second second planetary gear 45 are engaged with the sun gear 38, and the driving force is further transmitted to these gears.

  As shown in FIG. 5, the first planetary gear 39 and the first planetary arm 40 are attached to one end of the sun gear 38, and the second planetary gear 45 and the second planetary arm are attached to the other end. 44 is attached. The sun gear 38 and the first planetary gear 39 are arm-supported by the first planetary arm 40, and the first planetary gear 39 is given friction. Therefore, the first planetary arm 40 rotates according to the rotation of the sun gear 38. Using this operation, transmission of driving force from the first planetary gear 39 to the paper feed gear 19 via the control gear 24 is interrupted. Since the paper feed gear 19 is connected to the paper feed roller 11 via the paper feed shaft 10, the transmission of the driving force to the paper feed roller 11 is finally interrupted. Similarly, the sun gear 38 and the second planetary gear 45 are arm-supported by the second planetary arm 44, and the second planetary gear 45 is given friction. Therefore, the second planetary arm 44 rotates according to the rotation of the sun gear 38. Using this operation, transmission of driving force from the second planetary gear 45 to the paper feed gear 19 is interrupted.

  The trigger arm 43 is a regulating member that selectively interrupts transmission of driving force from the gears 39 and 45 to the control gear 24 and the paper feed gear 19. As shown in FIGS. 6A to 6D, the trigger arm 43 is rotatably provided and is urged clockwise or counterclockwise by a spring (not shown). Therefore, even if a rotational force is applied to the first planetary arm 40 or the second planetary arm 44 according to the rotation of the sun gear 38, the movement of these arms 40, 44 is restricted by the trigger arm 43, and the selective movement is selectively performed. The driving force is intermittent.

  Next, a specific operation of the drive transmission unit will be described with reference to FIGS. In the following description, the direction in which the sun gear 38 rotates counterclockwise, that is, the direction in which the transport roller 30 rotates in the direction in which the paper is transported in the transport direction is referred to as a first rotational direction P. Further, the direction in which the sun gear 38 rotates clockwise, that is, the direction in which the transport roller 30 rotates in the reverse direction of the paper is defined as a second rotation direction Q. Further, the operation of the drive transmission unit and the skew correction operation described below are controlled by a control unit (not shown) provided in the recording apparatus.

  (1) Standby State FIG. 6A shows the state of the drive transmission unit in the standby state where the driving force is not transmitted to the automatic paper feeder. The trigger arm 43 is in a position rotated clockwise by the spring bias, and fits into the recess of the first planetary arm 40 and the recess of the second planetary arm 44.

  In this state, first, the operation of the drive transmission unit when the transport roller 30 is rotated in the paper transport direction (first rotation direction P: counterclockwise) will be described. Since the sun gear 38 rotates counterclockwise, a force to rotate counterclockwise also acts on the first planetary arm 40 including the first planetary gear 39. However, since the movement is inhibited by the trigger arm 43, the driving force is not transmitted to the control gear 24. Since the second planetary arm 44 including the second planetary gear 45 tries to rotate counterclockwise, the second planetary gear rotates clockwise, but no driving force is transmitted to the paper feed gear 19.

  Next, the operation of the drive transmission unit when the conveyance roller 30 is rotated in the paper reverse feeding direction (second rotation direction P: clockwise) will be described. Since the sun gear 38 rotates clockwise, the first planetary arm 40 does not have a counterclockwise force. The second planetary arm 44 including the second planetary gear 45 tries to rotate clockwise, but the trigger arm 43 blocks the movement of the second planetary arm 44. Therefore, the second planetary gear 45 rotates counterclockwise, but the second planetary arm 44 cannot rotate and no driving force is transmitted to the paper feed gear 19.

  As described above, in the standby state, no driving force is transmitted to the paper feed roller 11 regardless of which direction the transport roller 30 rotates.

  (2) First Transport Mode FIG. 6B shows the state of the drive transmission unit when the automatic paper feeder is activated. In this mode, the transport roller 30 is rotated in the paper transport direction (first rotation direction P: counterclockwise). Since the trigger arm push-down cam portion 46 of the carriage unit (not shown) pushes down the left arm portion of the trigger arm 43 downward, the trigger arm 43 rotates counterclockwise against the biasing force of the spring. As a result, the rotation restricting function of the trigger arm 43 with respect to the first planetary gear 39 and the second planetary gear 45 is released. Since the sun gear 38 rotates in the first rotation direction P and the first planetary arm 40 including the first planetary gear 39 also rotates counterclockwise, the first planetary gear 39 engages with the control gear 24. Then, a driving force is transmitted from the paper feed gear 19 to the feed roller 11 via the paper feed shaft 10. The rotation direction of the feeding roller 11 at this time is clockwise rotation and coincides with the paper transport direction. Although the second planetary gear 45 rotates clockwise, the second planetary arm 44 including the second planetary gear 45 tries to rotate counterclockwise. No drive force is transmitted to 19.

  Here, the structure of the control gear 24 will be supplemented. A rail groove 47 is cut in the side surface of the control gear 24. A portion of the rail groove 47 has an enlarged groove width, and the first planetary arm 40 fits into the engaging portion 48 when the control gear 24 is in the phase shown in FIG. 6A. When the control gear 24 rotates slightly counterclockwise to the state shown in FIG. 6B, the first planetary arm 40 does not rotate even if the transport roller 30 is reversed, and the first planetary gear 39 does not rotate. Locked to. Such a configuration is adopted because when the second skew correction operation described later is performed, the conveying roller 30 (sun gear 38) is reversely rotated during feeding, and then again the conveying roller 30 (sun gear 38). This is because it is necessary to rotate in the transport direction. That is, if this mechanism is not provided and the first planetary arm 40 freely rotates, the first planetary arm 40 returns to the standby state when the sun gear 38 is reversed. Then, during the subsequent re-forward rotation, the first planetary gear 39 is not connected to the control gear 24 until the first planetary arm 40 rotates again and engages with the rail groove 47. The operation of the roller 11 is delayed. According to this configuration, since such an operation delay does not occur, the feeding roller 11 can operate in response to the rotation of the transport roller 30 (sun gear 38) immediately.

  By adopting such a fixing mechanism for the first planetary arm 40, the carriage may be located anywhere after the first planetary arm 40 is locked after the first trigger is applied. There is also an advantage that can be performed. When the spring pressure of the pressure plate 16 is applied to the feeding roller 11 by the rise of the pressure plate 16, the control gear 24 receives a force in a direction away from the first planetary gear 39, and the control gear 24 and the first planetary gear 39 As a result, the amount of rotation becomes unstable. However, according to this fixing mechanism, such a problem is easily solved.

  A one-way clutch is incorporated in the control gear 24 so that it cannot rotate in the clockwise direction in FIGS. Such a configuration is adopted because the conveyance roller 30 (sun gear 38) is reversed during feeding during the first skew correction operation described later, and at that time, the feeding roller 11 is not reversed. This is necessary. Since the one-way clutch is configured to prevent clockwise rotation, the control gear 24 and the feeding roller 11 can be operated even when the sun gear 38 is reversed and a clockwise force is applied to the control gear 24. Is prevented from rotating.

  In this case, if the control gear 24 directly receives a driving force in the clockwise direction from the first planetary gear 39, an excessive force is applied to the control gear 24, which may be damaged. Therefore, as a preventive measure, the first planetary gear 39 is composed of two coaxial gears (not shown) and a clutch mechanism embedded therebetween. The clutch mechanism is configured to transmit a driving force when the sun gear 38 rotates in the first rotation direction P, and does not transmit a driving force when the sun gear 38 rotates in the reverse direction. The control gear 24 can be protected in the case of reverse rotation. The above is the description of the drive transmission unit when the apparatus is activated.

  (3) Second Transport Mode FIG. 6C shows the state of the drive transmission unit when the drive pulley is rotated in the direction in which the transport roller reversely transports the paper (clockwise in the figure) with the trigger arm removed. Is shown. In this mode, the transport roller 30 (sun gear 38) is rotated in the paper reverse feed direction (second rotation direction Q: clockwise). When the sun gear 38 rotates clockwise, the trigger arm 43 is removed, so that the second planetary arm 44 including the second planetary gear 45 rotates clockwise and engages with the paper feed gear 19. Thus, the driving force is transmitted. The rotation direction of the feeding roller 11 at this time is clockwise rotation and coincides with the paper transport direction. The first planetary arm 40 is in a locked state, but the first planetary arm 40 including the first planetary gear 39 is idled by a clutch mechanism embedded in the first planetary gear 39. . The method of using this conveyance mode will be described in detail when the second skew correction operation described later is described.

  (4) Third Transport Mode FIG. 6D shows the state of the drive transmission unit when the carriage is moved and the trigger arm is lowered after the first transport mode.

  First, the operation of the drive transmission unit when the transport roller 30 is rotated in the paper transport direction (first rotation direction P: counterclockwise) will be described. When the sun gear 38 rotates counterclockwise, the second planetary arm 44 including the second planetary gear 45 tries to rotate counterclockwise, so that no driving force is transmitted to the paper feed gear 19. On the other hand, since the first planetary arm 40 including the first planetary gear 39 rotates counterclockwise, the first planetary gear 39 engages with the control gear 24, and the feed shaft 19 to the feed shaft 10. The driving force is transmitted to the feeding roller 11 via the. The rotation direction of the feeding roller 11 at this time is clockwise rotation and coincides with the paper transport direction.

  Next, the operation of the drive transmission unit when the conveyance roller 30 is rotated in the paper reverse feeding direction (second rotation direction P: clockwise) will be described. When the sun gear 38 rotates clockwise, the second planetary arm 44 including the second planetary gear 45 tries to rotate clockwise. However, since the trigger arm 43 inhibits the movement of the second planetary arm 44, the second planetary arm 44 cannot rotate and the driving force is not transmitted to the paper feed gear 19. On the other hand, the first planetary arm 40 is in a locked state, but the first planetary arm 40 including the first planetary gear 39 is idled by a clutch mechanism embedded in the first planetary gear 39. . That is, in this case, the driving force is not transmitted to the paper feed gear 19, and the paper feed gear 19 is fixed.

  Next, the configuration of the paper stacking unit of the automatic paper feeder will be described with reference to FIGS. The sheet stacking unit uses a sheet conveyance reference portion 16a provided so as to protrude from a part of the pressure plate 16 as a reference on the side of the sheet, and controls the side plate opposite to the pressure plate 16 and the sheet conveyance reference portion 16a. It consists of 18. In a so-called standby state in which the automatic paper feeder is not conveying paper, the pressure plate 16 is fixed at a predetermined position in a direction away from the feed roller 11. In this state, a sufficient gap is secured between the feeding roller 11 and the pressure plate 16 for stacking a plurality of sheets.

  The automatic paper feeder is adapted to an arbitrary paper width within a predetermined width range. The plurality of sheets are placed in the gaps along the sheet conveyance reference portion 16a, and then the side guide 18 is moved in the direction of arrow C (FIG. 1) to match the sheet width. For this reason, movement of the set bundle of sheets in a direction orthogonal to the sheet conveyance direction Y is restricted, and stable conveyance is possible. The side guide 18 is slidably attached to the pressure plate 16 but is engaged with and fixed to a latch groove (not shown) formed in the pressure plate 16 so as not to move carelessly. Therefore, when the side guide 18 is moved, the lever portion (not shown) provided on the side guide 18 is operated to release the latch and move it.

  Since the sheet to be set is inclined and stacked with respect to the horizontal plane of the recording apparatus, the sheet is urged downward by gravity, but the leading end of the sheet abuts against a sheet leading end reference portion 15 a fixedly provided on the base 15. In the present embodiment, the paper leading edge reference portion 15a has a rib shape in order to reduce the load during paper feeding.

  The pressure plate 16 has a center of rotation at the upper end and can be rotated. A paper feed tray 41 is provided on a substantially extended line of the pressure plate 16 and supports the rear end portion of the set paper. One end of the paper feed tray 41 is rotatably attached to the exterior portion of the recording apparatus. When the recording apparatus is not used, the paper feed tray 41 can be rotated and folded. The sheet feed tray 41 is provided with buckling prevention ribs 42. When a thin paper such as plain paper is set for a long period of time, a curl in a direction in which the leading edge is lifted is attached to the paper. It is preventing. The operation of the pressure plate 16 is regulated by a pressure plate spring 17 and a cam (not shown) provided in the control gear 24. That is, the pressure plate 16 is urged to rotate in the direction of the feeding roller 11 by the pressure plate spring 17. Further, the pressure plate 16 is separated from the feeding roller 11 by forcibly rotating the pressure plate 16 when a cam (not shown) provided in the control gear 24 presses the pressure plate 16. The above urging / separating operation is performed at a predetermined timing, which will be described later, and a paper feeding operation is performed.

  Next, the configuration of the sheet feeding / separating unit will be described. The set paper 20 is pressed against the feeding roller 11 by the operation of the pressure plate 16 at a predetermined timing. At the same time, the feeding roller 11 is driven to rotate, and the uppermost sheet of stacked sheets in contact with the feeding roller 11 is conveyed by the frictional force of the feeding roller 11. As described above, the feeding roller 11 conveys the sheet by a frictional force. Therefore, the feeding roller 11 is preferably made of rubber having a high friction coefficient, such as EPDM (Ethilene propylene terpolymer), or urethane foam. is there.

  Usually, since the frictional force between the feeding roller 11 and the uppermost sheet is larger than the frictional force between the uppermost sheet and the sheet immediately below, only the uppermost sheet is conveyed. However, for example, when there is an effect of burrs at the edge of the paper that can occur during paper cutting, when there is sticking between papers due to static electricity, or when using paper with a very large surface friction coefficient, A plurality of sheets may be pulled out by the roller 11 at a time. The automatic paper feeder of this embodiment includes a separation roller 12 for separating only the uppermost paper. Hereinafter, the configuration and operation of the separation roller 12 will be described.

  The separation roller 12 is provided opposite to the feed roller 11 so that the paper passes between the feed roller 11 at a position downstream of the first contact point between the feed roller 11 and the paper in the transport direction. ing. 7 and 8 are an exploded perspective view and a sectional view showing the configuration of the separation roller 12 and related parts. The separation roller 12 is fixedly attached to the clutch cylinder 12a, and a clutch shaft 12b is rotatably accommodated in the clutch cylinder 12a. A clutch spring 12c is wound around the clutch shaft 12b, and one of the winding ends of the clutch spring 12c is engaged with the clutch cylinder 12a. The surface of the separation roller 12 is made of rubber, urethane foam, or the like so as to have a friction coefficient comparable to that of the feeding roller 11. The clutch shaft 12b is formed of a molded part, and a gear is integrally formed at one end of the shaft. The clutch spring 12c is composed of a metal coil spring.

  When the separation roller 12 and the clutch cylinder 12a are rotated in the direction of the arrow in FIG. 8A with the clutch shaft 12b fixed, the clutch spring 12c wound around the clutch shaft 12b slides out of the clutch shaft 12b. When the separation roller 12 and the clutch cylinder 12a rotate by a predetermined angle, the clutch shaft 12b and the clutch spring 12c slide relatively and stably and maintain a predetermined torque. That is, the separation roller 12 functions as a torque limiter.

  The separation roller 12 is rotatably supported by the separation roller holder 21 via the clutch cylinder 12a and the clutch shaft 12b. When the separation roller spring 26 presses the separation roller holder 21, the separation roller 12 is moved to the feeding roller 11. Pressed. When there is no paper between the feeding roller 11 and the separation roller 12, the separation roller 12 is rotated in accordance with the rotation of the feeding roller 11. When a sheet of paper enters between the feeding roller 11 and the separation roller 12, the frictional force between the feeding roller 11 and the sheet is the frictional force between the separation roller 12 driven by a predetermined torque and the sheet. Therefore, the sheet is conveyed while the separation roller 12 is driven. When two sheets enter between the feeding roller 11 and the separation roller 12, the frictional force between the feeding roller 11 and the sheet in contact with the feeding roller 11 is larger than the frictional force between the sheets, Since the frictional force between the separation roller 12 and the sheet in contact with the separation roller 12 is larger than the frictional force between the sheets, slip occurs between the sheets. As a result, only the sheet in contact with the feeding roller 11 is conveyed, and the sheet on the separation roller 12 side is stopped and conveyed together with the non-rotating separation roller 12. The above is the outline of the separation unit using the separation roller 12.

  Next, the configuration of the double feed prevention unit will be described. As described above, when about two sheets of paper enter the nip between the feeding roller 11 and the separation roller 12, the separation roller 12 can separate them. However, if more sheets are entered, or only two sheets are fed and only the sheet in contact with the feed roller 11 is transported, the next sheet is fed continuously with the sheet remaining near the nip. If an attempt is made, a plurality of sheets may be conveyed simultaneously. In order to prevent this so-called double feed, a double feed prevention unit is provided.

  The double feed prevention unit is composed of a return lever 13. The return lever 13 is intruded into the paper passage path when setting paper or waiting for printing, and prevents the leading edge of the paper from inadvertently entering the back of the paper feeding device. When the paper feeding operation is started, the return lever 13 is opened and retracts from the paper transport path. Therefore, the return lever 13 does not hinder the progress of the paper during paper feeding. When the separation operation is completed, the return lever 13 enters an operation of returning the next and subsequent sheets in the nip portion between the feeding roller 11 and the separation roller 12. The return lever 13 that has finished returning the paper is rotated to a position where it is retracted from the paper conveyance path. When it is confirmed that the rear end of the paper is ejected from the automatic paper feeder, the return lever 13 is again in the standby position. Return to. The above is the outline of the double feed prevention unit using the return lever 13.

  Next, the operation sequence of the automatic paper feeder will be described. FIG. 9 is a timing chart showing an operation sequence of the automatic paper feeder. The figure shows the position of the pressure plate 16, the position of the return lever 13, the position of the separation roller 12, and the state of the torque limiter of the separation roller 12. The horizontal axis is the angle phase of the control gear 24. 10A to 10D are cross-sectional views illustrating states in each stage of the operation sequence of the automatic sheet feeder.

  In FIG. 9, an angle of 0 ° of the control gear 24 indicates the standby state of FIG. 10A, and a series of operations starts from this standby state. In the standby state, the drive transmission unit is controlled to be in the state of FIG. 6A. The pressure plate 16 is held at a position separated from the feeding roller 11, and the return lever 13 enters the paper passage path to prevent the leading edge of the set paper 20 from falling into the separation portion.

As shown in FIG. 10A, the distal end 23a of the lock lever 23 bites into a gear portion provided at the end of the clutch shaft 12b, so that the torque of the separation roller 12 can be generated. The separation roller 12 and the lock lever 23 are both attached to the separation roller holder 21. The separation roller holder 21 is attached to the base 15 so as to rotate about the rotation center 21a. The separation roller holder 21 is urged in the direction of the feeding roller 11 by a separation roller spring 26, and the separation roller 12 is in pressure contact with the feeding roller 11. The rotation center 21 a of the separation roller holder 21 is set to be downstream in the conveyance direction and below the tangent line at the contact point of the feeding roller 11 with the pressure plate 16. Therefore, when separating and feeding thick paper or the like, even if the paper enters between the separation roller 12 and the feed roller 11 and the separation roller 12 tries to be separated from the feed roller 11, the pressure contact of the separation roller 12 is reversed. The force increases and the separation performance of the nip portion is maintained. Also, with this arrangement, the rotation center 21a of the separation roller holder 21 is set below the tangent line at the contact point between the feeding roller 11 and the separation roller 12 and is also downstream in the transport direction, and thus occurs in the separation unit. The pressure contact force of the separation unit is also increased by the conveyance force from the conveyance roller 11. (Pressure contact force by biting)
The merit of using the pressure contact force by this biting will be described. In the separation unit, the frictional force between the papers needs to be smaller than the paper holding force of the separation roller 12 due to the torque generated by the torque limiter (separation roller 12). On the other hand, the pressure contact force between the feed roller 11 and the separation roller 12 tends to decrease due to the pressure contact between the pressure plate 16 and the feed roller 11. If the pressure contact force is generated only by the pressure contact force of the spring, it is necessary to increase the spring force in order to compensate for the decrease in the pressure contact force. However, when the spring force is increased, only the frictional force between the papers increases, and so-called double feeding is likely to occur. In order to prevent this, it is necessary to increase the torque of the torque limiter and to increase the driving force. Also, a large force is required when the separation roller 12 is separated. On the other hand, if the biting force is used, the frictional force between the sheets does not increase, so that even when two sheets of paper are sandwiched between the separation nips, they can be easily separated with an appropriate pressure contact force. In this way, sufficient separation performance can be realized with a small spring force by balancing the pressure contact force caused by the biting force and the pressure contact force caused by the spring.

  The base 15 is further provided with a front-stage regulating holder 22 that rotates about the same rotation center 21a. The front-stage regulation holder 22 is biased by a front-stage regulation holder spring 33 (see FIG. 4) so that a part of the front-stage regulation holder 22 abuts against the base 15 and the position thereof is determined. The front stage regulation holder 22 rotates when the front stage regulation holder action surface 28 a of the release cam 28 contacts the front stage regulation holder 22. The front end of the paper 20 is supported by the paper front reference portion 15a, and the back surface of the paper bundle is supported by the pressure plate 16 and is on standby. The above is the description of the standby state.

  Next, the process from the start of paper feeding until the paper is delivered to the printing unit will be described according to the angle of the control gear 24. The paper feeding operation of the automatic paper feeder can be divided into two operations, a separating operation and a conveying operation. First, the separation operation will be described.

  As described above, when the carriage reaches the paper feed position, the trigger arm 43 is released. In this state, when the drive pulley 35 is rotated in the direction in which the transport roller 30 forwards the sheet, the drive transmission unit of the recording apparatus is in the first transport mode shown in FIG. 6B, and the first planetary gear 39 is controlled. Engagement with the gear 24 starts feeding by the automatic sheet feeder. Further, the first planetary arm 40 is locked. When the feeding is started and the feeding roller 11 starts to rotate in the K direction in FIG. 10B, the separation roller 12 is rotated by the rotation of the feeding roller 11, so that the clutch spring 12c in the separation roller 12 has a predetermined torque. It is charged until.

  When the control gear 24 rotates to the angle θ1 shown in FIG. 9 along with the rotation of the feeding roller 11, the return lever 13 is first opened by the action of a control cam (not shown) provided on the control gear 24. A sheet conveyance path is secured.

  When the paper feeding operation proceeds and the control gear 24 rotates to the angle θ2 shown in FIG. 9, the pressure plate 16 is released from the fixed state by the action of the control cam provided on the control gear, and the loaded paper 20 is moved to the pressure plate spring. 17 starts to be pressed in the direction of the feeding roller 11. Subsequently, as illustrated in FIG. 10B, the sheet conveyance is started, and the uppermost sheet of the sheets 20 is conveyed by the feeding roller 11.

  Depending on the frictional force between the sheets, not only the uppermost sheet but also the next and lower sheets may be fed. For this reason, the passage of the paper is first restricted to several sheets or less by the gap formed by the front stage regulation 22 a provided in the front stage regulation holder 22 and the feeding roller 11. When the sheet feeding is further continued, the sheet reaches the separation portion constituted by the nip portion between the feeding roller 11 and the separation roller 12. The separation roller 12 tries to rotate counterclockwise in the drawing as the paper advances, but as shown in FIG. 10B, the lock lever 23 bites into the clutch shaft 12b. The lock lever 23 prevents rotation. For this reason, the separation roller 12 rotates while receiving a torque necessary for separating the paper 20 from the clutch spring 12c, and the paper 20 is separated.

  When the control gear 24 rotates to the angle θ3 shown in FIG. 9, the separating operation of the pressure plate 16 is started, and at the same time, the double feed prevention operation by the return lever 13 is also started.

  When the control gear 24 rotates to the angle θ4 shown in FIG. 9, the release cam 28 rotates in the L direction as shown in FIG. 10C by the action of the control cam provided in the control gear 24. The front-stage regulating holder action surface 28a of the release cam 28 contacts the front-stage regulating holder 22 and rotates the front-stage regulating holder 22 in the P direction. As a result, the upstream regulation 22a is moved in a direction away from the feed roller 11, and the gap with the feed roller 11 is widened. Since the pre-regulation 22a restricts the paper 20 from entering the separation unit until then, a plurality of papers may enter the gap formed by the feeding roller 11 and the pre-regulation 22a. In this case, a large force may be required for the sheet returning operation by the return lever 13 performed thereafter due to the pinching force. However, by retracting the position of the front-stage regulation 22a in this way, it is possible to reduce the force required for the paper return operation by the return lever 13.

  Next, the operation of the control cam provided in the control gear 24 causes the tip of the return lever 13 to pass through the nip portion between the feeding roller 11 and the separation roller 12 and return the next and subsequent sheets in the separation nip. Begin. Immediately after that, when the control gear 24 rotates to the angle θ5 shown in FIG. 9, the release cam 28 is further rotated in the L direction by the action of the control cam provided in the control gear 24, and the upstream regulation holder 22 is further moved in the P direction. Turn to. The separation roller holder working surface 22b of the front-stage regulating holder 22 contacts the separation roller holder 21 and rotates the separation roller holder 21 including the separation roller 12 in the P direction.

  As described above, when the paper 20 is returned by the return lever 13, the restriction of the preceding restriction 22a is first released, and then the separation roller holder 21 is released when the tip of the return lever 13 passes through the separation nip. . Since all the mechanical parts that can become a resistance during the returning operation are released, the returning operation can be easily performed with a small force.

  Thereafter, the leading ends of all other sheets except the fed sheet are conveyed in the reverse direction to the sheet leading end reference portion 15a. When the control gear 24 rotates to the angle θ6 shown in FIG. 9, the pressure plate 16 finishes the separating operation from the feeding roller 11 and returns to the standby state position.

  When the control gear 24 rotates to the angle θ7 shown in FIG. 9, the paper returning operation is almost completed. The release cam 28 is rotated in the M direction by the action of the control cam provided in the control gear 24, and the front-stage regulating holder 22 and the separation roller holder 21 released by the release cam 28 are rotated in the Q direction. Each returns to the position before release.

  When the paper return operation is completed, the return lever 13 moves not to the initial standby position but to a further rotated retreat position as shown in FIG. 10D. At this time, the control gear 24 rotates to an angle θ8 shown in FIG. By moving the return lever 13 to the retracted position, it is possible to prevent the return lever 13 from coming into contact with the paper 20 being conveyed and inadvertently giving resistance, and to obtain a good printing result. The above is the description of the separation operation. At this stage, the sheet has not yet been delivered to the printing unit.

  Here, the relationship between the separation operation described above and the skew correction operation will be described. In the present invention, two operations can be selectively executed as the skew correction operation. The first skew correction operation is a method in which the sheet is sandwiched between the conveyance rollers 30 in the first conveyance mode and then reversely conveyed in the third conveyance mode while the sheet is held by the feeding roller 11. The second skew correction operation is a method in which the sheet is transported to the upstream side in the transport direction of the transport roller 30 in the first transport mode and then abutted against the transport roller 30 in the second transport mode.

  When the first skew correction operation is selected, first, the trigger arm 43 is released by the trigger arm push-down cam portion 46 of the carriage unit (FIG. 6A). Next, the drive pulley 35 is rotated in the direction in which the transport roller 30 transports the paper (counterclockwise in the figure) (FIG. 6B). Next, the trigger arm 43 is lowered, and the drive pulley 35 is further rotated in the direction in which the transport roller 30 normally transports the paper (counterclockwise in the figure) (FIG. 6D). That is, when the first skew correction operation is selected, the separation operation is performed while the transport roller 30 is always driven in the paper transport direction (first rotation direction).

  When the second skew correction operation is selected, first, the trigger arm 43 is released by the trigger arm push-down cam portion 46 of the carriage unit (FIG. 6A). Next, the drive pulley 35 is rotated in the direction in which the transport roller 30 transports the paper (counterclockwise in the figure) (FIG. 5B). Up to this point, the operation is the same as the first skew correction operation. When the control gear 24 rotates to the phase θ12 shown in FIG. 9, the drive pulley 35 is rotated in the direction in which the transport roller 30 reversely transports the paper (clockwise in the figure) while the trigger arm 43 is released (FIG. 9). 6D). In this state, the separation operation is performed from the phase θ12 to the end of the separation operation. That is, until θ12 shown in FIG. 9, the conveyance roller 30 conveys the sheet while being driven in the sheet conveyance direction (first rotation direction). Thereafter, the separation operation is performed while being driven in the paper reverse feeding direction (second rotation direction).

  Next, the conveying operation will be described. When the control gear 24 rotates to the angle θ8 shown in FIG. 9, the return lever 13 rotates in the N direction by the action of the control cam provided in the control gear 24, as shown in FIG. 10D. The lock lever operating surface 28c of the return lever 13 contacts the lock lever 23 and rotates the lock lever in the R direction. As a result, the distal end portion 23a of the lock lever 23 that has bitten into the gear portion of the clutch shaft 12b until then is disengaged from the gear, and the clutch shaft 12b can freely rotate. Since the clutch spring 12c does not slip even when the separation roller 12 and the clutch cylinder 12a rotate, the clutch shaft 12b loses the function of the torque limiter, and the separation roller 12 rotates without torque with respect to the feeding roller 11. Changes to a driven roller.

  As the transport operation continues, the leading edge of the paper 20 eventually reaches the nip portion between the pinch roller 29 and the transport roller 30. At this time, when the first skew correction operation is selected, the transport roller 30 continues to rotate counterclockwise and rotates the feed roller 11 in the paper transport direction. When the second skew correction operation is selected, the transport roller 30 rotates clockwise and continues to rotate the feed roller 11 in the paper transport direction. The recording apparatus performs a skew correction operation of the paper here, which operation will be described later.

  When the control gear 24 rotates to an angle θ10 shown in FIG. 9, the release cam rotates in the L direction in FIG. 10D by the action of the control cam provided in the control gear 24. The front-stage regulating holder 22 and the separation roller holder 21 that have been released by the release cam 28 rotate in the P direction, and are again released.

  When the control gear 24 rotates to an angle θ11 shown in FIG. 9, a missing tooth portion (not shown) provided in the gear portion of the control gear 24 comes to a position facing the paper feed gear 19. The state at this time is shown in FIG. 6E. A phase sensor (not shown) detects this phase and rotates the conveyance roller 30 in the first rotation direction. Since the first planetary arm 40 is at a position that can be separated from the control gear 24, the first planetary gear 39 and the control gear 24 are disengaged by rotating clockwise by the rotation of the transport roller 30. Is done. Further, since the carriage is moved to a portion other than the paper feed start position, the trigger arm 43 is rotated clockwise by the spring force, and the first planetary arm 40 is locked again at a position where the driving force is not transmitted. . This phase is the print position.

  The transport roller 30 rotates forward and backward for printing, but the automatic paper feeder does not operate because the first planetary arm 40 is locked at a position where the driving force is not transmitted. In addition, after the separation of the first sheet is completed and the second and subsequent sheets are returned to the sheet loading unit, the automatic paper feeder places a load on the conveyance of the first sheet as much as possible. There is no such thing. That is, since the separation roller 12 is separated from the feeding roller 11 and does not generate torque, even if paper touches the separation roller 12, it does not cause a large load. The feeding roller 11 is also rotatable because the toothless portion is located at the position facing the paper feed gear 19 and does not drag the gear train even if it touches the paper. The return lever 13 is also waiting at a position as far away from the feeding roller 11 as possible. By placing the automatic sheet feeder in such a state, it is possible to prevent the sheet conveyance amount of the conveyance roller 30 from being affected by the load from the automatic sheet feeder and adversely affecting the image.

  When printing is completed, the carriage is returned to the paper feed position and the transport roller 30 is rotated forward. In the same manner as described above, the driving force is transmitted to the control gear 24, and the control gear 24 rotates to the standby position (0 °). At this time, the return lever 13 enters the sheet passing path by the cam (not shown) and does not press the lock lever 23, so that the separation roller 12 changes to a state where torque can be generated. The separation roller 12 is brought into pressure contact with the feeding roller 11, and the upstream regulation 22 returns to the raised position where the separation operation can be performed. In this state, when the carriage is retracted from the paper feeding position and the transport roller 30 is reversed, the first planetary arm 40 operates clockwise, the transmission of the driving force is cut off, and the trigger arm 43 also rotates clockwise. It becomes locked again. All the drive transmission units return to the initial standby position, and the series of operations ends. The above is the description of the transport operation.

  Next, detailed description of the skew correction operation will be given. First, the first skew correction operation will be described. The first skew correction operation is performed when the leading edge of the paper 20 reaches the nip portion between the pinch roller 29 and the conveyance roller 30 during the conveyance operation. At this time, the phase of the automatic feeding device is in a state of θ9 in FIG. 9, the cross section of the separation portion corresponds to FIG. 10D, and the drive transmission portion corresponds to FIG. 6D. When the leading edge of the paper 20 reaches the nip portion, the transport roller 30 is rotating forward, so that the paper is caught in the nip portion. The conveyance roller 30 is stopped when the leading edge of the paper 20 comes out from the nip portion by about 3 mm, and then the conveyance roller 30 is reversed. Note that the passing amount of the leading edge of the sheet is not limited to 3 mm. At this time, the first planetary arm 40 is locked to the control gear 24, but the clutch mechanism of the first planetary gear 39 operates so as to release the driving force, and the one-way clutch of the control gear 24 works. Therefore, the feeding roller 11 does not move and is fixed. Accordingly, when the paper is fed backward by the transport roller 30, the paper 20 is bent. The leading edge of the sheet 20 is pressed against the nip portion between the pinch roller 29 and the conveying roller 30 by the force to return the deflection. Even if the paper 20 has been transported obliquely, the leading edge of the paper 20 is along the nip portion between the transport roller 30 and the pinch roller 29, the traveling direction of the paper 20 is corrected, and the skew of the paper is corrected. .

  Next, the second skew correction operation will be described. First, the reason for performing the second skew correction operation will be described. In the first skew correction operation, the nip pressure between the feeding roller 11 and the separation roller 12 acts on the paper in two stages. One is when the leading edge of the paper 20 is pressed against the nip of the transport roller 30 and enters the nip by the forward rotation of the transport roller 30. If the pressing force of the paper 20 is weak, such as when the paper 20 is thick, the paper 20 is not given sufficient conveying force to overcome the spring force and lift the pinch roller 29 and enter the nip. As described above, this conveying force is generated only by the pressure contact force of the nip between the feeding roller 11 and the separation roller 12, but at this stage, both the pressing force and the biting force of the separation roller spring 26 are included in the pressure contact force. Since it contributes, sufficient conveyance force arises.

  The second time is when the paper 20 is held in the nip of the transport roller 30 and fed backward. At this time, as described above, since the feeding roller 11 is not moving, the pressure contact force is generated only by the spring pressure of the separation roller spring 26. For this reason, when the paper 20 is thick, the reaction force of the paper 20 is large, so the paper 20 may not be held at the nip of the feed roller 11 and may be returned upstream in the transport direction. In this case, sufficient deflection is not formed on the sheet 20, and skew is not corrected. This is especially true when paper dust or the like adheres to the feed roller 11 and the frictional force decreases. However, if the separation spring pressure is increased in order to obtain a sufficient pressure contact force, double feeding occurs as described above.

  In order to solve this problem, in this automatic paper feeder, in order to increase the pressure contact force of the nip between the feed roller 11 and the separation roller 12, one end of the feed roller 11 is provided with a bearing having a long-hole bearing groove. 27 (details will be described later). However, in this automatic paper feeder, the nip pressure between the feeding roller 11 and the separation roller 12 is further increased by further performing the second skew correction operation.

  In the second skew correction operation, the conveying roller 30 rotates clockwise to perform the separation operation from the time when the phase of the control gear 24 becomes θ12 to the end of the separation operation. That is, until the phase θ12 in FIG. 9, the conveyance roller 30 is rotated counterclockwise, and thereafter, the conveyance roller 30 is rotated clockwise to convey the paper 20. Accordingly, the sheet 20 reaches the nip portion between the conveying roller 30 and the pinch roller 29 that are rotating in reverse. The second skew correction operation is performed in this state. At this time, the phase of the automatic feeding device corresponds to θ9 in FIG. 9, the separation portion corresponds to FIG. 10D, and the drive transmission unit corresponds to FIG. 6C.

  When the leading edge of the paper 20 reaches the nip portion, the conveyance roller 30 is reversed, and the paper 20 hits the nip. After the leading edge of the paper 20 reaches the nip, the feeding roller 11 further pushes the paper 20 about 3 mm and stops. This pushing amount is not limited to 3 mm. The sheet 20 struck by the feeding roller 11 against the nip of the conveying roller 30 that is reversed causes a deflection. The leading edge of the sheet is pressed against the nip portion of the conveyance roller 30 by the force for returning the deflection. Therefore, even if the paper 20 has been transported obliquely, the end of the paper 20 is along the nip portion of the transport roller 30 and the pinch roller 29, the traveling direction of the paper 20 is corrected, and the skew of the paper is corrected. .

  Thereafter, the transport roller 30 is rotated forward. Since the second planetary arm 44 including the second planetary gear 45 tries to rotate counterclockwise, the second planetary arm 44 is separated from the paper feed gear 19 and the driving force from the second planetary gear 45 to the feeding roller 11 is cut off. The On the other hand, since the first planetary arm 40 including the first planetary gear 39 is locked by the rail groove 47 of the control gear 24, the first planetary gear 39 passes through the control gear 24 and the paper feed gear 19. Is rotated in the paper transport direction. As a result, the feeding roller 11 conveys the sheet 20 to the downstream side of the nip of the conveying roller 30.

  As described above in detail, in the first skew correction operation, first, the leading edge of the paper 20 is once taken out downstream of the nip of the conveying roller 30. Next, in a state where the rear side of the sheet 20 is held at the nip between the stopped feeding roller 11 and the separation roller 12 where the torque limiter torque is not generated, the sheet 20 is moved upstream by the conveying roller 30. return. In the case of thick paper, the skew correction operation may be performed when the separation roller 12 rotates due to the holding force of the separation roller 12 being defeated by the force that the paper 20 is returned backward by the conveyance roller 30. Suitable for

  In the second skew correction operation, the sheet 20 is abutted against the nip of the transport roller 30 rotating in reverse by the feeding roller 11 to correct skew. In other words, since the biting force of the separation roller 12 can be used, there is an advantage that deflection can be easily formed even on the thick paper 20. On the other hand, since the paper 20 is abutted against the nip of the conveying roller 30 that is reversed, when the paper 20 is a thin paper, scratches and scratches at the front end of the paper are likely to occur. Therefore, this skew correction operation is suitable for thick paper. The above is the description of the first and second skew correction operations.

  Here, the function and effect of the bearing groove 27a of the bearing will be described. FIG. 11A is a state diagram during the separation operation, and FIG. 11B is a state diagram after performing the skew correction operation of the paper. 12 is an enlarged view of the separating portion of FIG. 11A, and FIG. 13 is an enlarged view of the separating portion of FIG. 11B.

  As shown in FIG. 12, the bearing groove 27a is a slot-like groove. The center of the right arc portion in the drawing (hereinafter sometimes referred to as a normal center) coincides with the rotation center of the paper feed gear 19. The paper feed shaft 10 and the feed roller 11 are directed upstream in the paper feed direction along the slot of the long bearing groove 27a toward the center of the left arc in the drawing (hereinafter sometimes referred to as an assist position). In addition, it is supported so that it can move in the direction of biting into the separation roller 12. When the feeding roller 11 moves upstream in the paper feeding direction, the separation roller 12 is pushed and pushed down by the feeding roller 11, and the separation roller spring 26 is contracted to increase the pressure contact force.

  Next, the operation of the bearing will be described. As shown in FIG. 11A, the sheet feeding shaft 10 during the separation operation is on the downstream side (normal center) in the transport direction of the bearing groove 27a of the bearing. At the start of separation, since the sheet is not sandwiched between the nip between the feeding roller 11 and the separation roller 12, when the feeding roller 11 rotates forward, the separation roller 12 rotates forward along with the feeding roller 11. At this time, the feeding roller 11 receives a force in a direction in which the feeding roller 11 is moved upstream in the paper feeding direction by the reaction force of the separation roller 12 (torque limiter) (hereinafter referred to as a first force). The feeding roller 11 also receives a force from the pressure plate 16 along the bearing groove 27a of the bearing 27 in a direction in which the feeding roller 11 is moved in the right circular arc direction having a normal center (hereinafter referred to as a second force). Further, the feeding roller 11 is originally pressed from the separation roller 12 toward the normal center (hereinafter, third force).

  Since the direction of the long hole 27a is set in the direction in which the feeding roller 11 pushes the separation roller 12, the component of the first force in the long hole direction is very small. On the other hand, since the component force of the second and third forces in the long hole direction is large, the conveyance is started in a state where the feed roller 11 is at the normal center of the long hole 27a. When the center of the feeding roller 11 moves to the left arc portion (assist position) of the long hole 27a, the separation roller 12 may be inclined, and the sheet may be conveyed at an angle. Since it is at 11 normal centers, skew does not occur.

  When the separation operation proceeds and one sheet 20 enters the nip of the separation roller 12, the separation roller 12 (torque limiter) works in the same manner, so that the feeding roller 11 is at the normal center of the long hole 27a. When the two sheets 20 enter the nip of the separation roller 12, the torque limiter does not rotate, and the first force is generated only by the force caused by the frictional load between the sheets, so the first force decreases. Accordingly, the feeding roller 11 is still in the normal center of the feeding roller 11. As the feeding further proceeds, the pressure plate 16 is moved away, so the second force disappears, but the component force of the first force in the direction of the long hole is very small. The component in the direction of the long hole is excellent, and the center of the feeding roller 11 is at the normal center. When the separation further proceeds, separation of the nip portion between the feeding roller 11 and the separation roller 12 starts. At this time, since the third force disappears, the center of the feeding roller 11 moves in the assist position direction, but the nip portion is continuously separated. At this time, since the sheet 20 is not pressed against the feeding roller 11, even if the feeding roller 11 is inclined, the conveying force in the oblique direction hardly acts and does not cause skewing. Since the separation operation is performed even when the center is the assist position, the lock claw release of the separation roller 12 (torque limiter) is smoothly performed. The bearing portion of the paper feed shaft 10 on the side to which the paper feed gear 19 is attached is not a long hole, but is set to absorb rattle at the fitting portion. For this reason, even if the feeding roller 11 is inclined and the axis of the sheet feeding shaft 10 changes obliquely, the sheet feeding shaft 10 rotates smoothly.

  As the feeding further proceeds, the separation roller 12 comes into pressure contact with the feeding roller 11 again. Since the torque limiter is not working, the first force hardly works, the rotation center of the feeding roller 11 moves again to the normal center, and the conveyance of the paper is resumed. Accordingly, even at this stage, the sheet is not conveyed obliquely.

  When the first skew correction operation is selected, when the paper feeding further proceeds, the leading edge of the paper 20 is caught in the nip of the transport roller 30, the transport roller 30 stops normal rotation, and the feed roller 11 is turned on. While stopped, the conveyance roller 30 reverses to perform skew correction. When the paper 20 is a hard paper, a large deflection is not formed, so that the nip portion between the feeding roller 11 and the separation roller 12 receives a force from the paper 20 in the upstream direction. Since the feeding roller 11 is stopped, the biting force does not work as at the time of separation, and the separation roller 12 is separated from the feeding roller 11 because it is pressed against the feeding roller 11 only by the separation spring force. I will try. However, at this time, the component of the frictional force of the paper 20 in the long hole direction also acts on the feed roller 11, and the feed roller 11 is moved toward the assist position of the long hole 27 a to push down the separation roller 12. As a result, the spring reaction force of the separation roller spring 26 increases and the pressure contact force increases, so that the holding force of the separation roller 12 and the feeding roller 11 increases.

  On the other hand, when the second skew correction operation is selected, the feeding roller 11 is rotated in the forward direction with the transport roller 30 reversed, so that when the paper feeding further proceeds, the leading edge of the paper 20 It reaches the nip portion between the conveying roller 30 and the pinch roller 29 rotating in reverse. Then, while the feeding roller 11 and the separation roller 12 are rotated in the forward direction, the leading edge of the paper 20 is abutted against the nip portion, and the skew of the paper is corrected. Therefore, in the second skew correction operation, the biting force of the separation roller 12 is generated, so that the force for pushing the paper 20 into the transport roller 30 is larger than that in the first skew correction operation. Further, similarly to the first skew correction operation, the feeding roller 11 moves toward the assist position of the long hole 27a due to the pushing force of the feeding roller 11, and the separation spring force increases. Even in this case, the sheet 20 can be reliably held at the separation nip portion.

  When the first or second skew correction operation is completed, the transport roller 30 is rotated forward again. At this time, the drive transmission unit is in a state where the feeding roller 11 is also driven. However, even if the transport roller 30 that has been reversely rotated until just before is rotated forward, the feed roller 11 does not rotate immediately due to backlash, other backlash, deflection, or the like. The amount of non-rotation was about 3 mm at least in terms of the paper transport distance in the experimental machine. That is, while the sheet is conveyed by about 3 mm, the feeding roller 11 does not start normal rotation, the conveying force from the feeding roller 11 is not received, and the leading edge of the sheet is pushed into the nip portion only by the sheet abutting force. There is a need. However, due to the configuration in which the feeding roller 11 is supported by the elongated hole 27a, the sheet 20 is slightly fed by the conveying roller 30, and the rotation center of the feeding roller 11 returns to the normal center of the elongated hole 27a. Therefore, the deflection of the sheet, that is, the abutting force is preserved, and the sheet 20 can be surely pushed into the nip portion, and the holding stability is ensured. Thereafter, when the transport roller 30 further rotates forward, the backlash of the drive transmission unit is eliminated, and the feed roller 11 starts to rotate forward with a slight delay from the transport roller 30.

  In the case of the present invention, in order to reliably push the leading edge of the paper into the nip portion, the second skew correction operation is performed when passing thick paper, and the first when passing relatively thin paper. The skew correction operation is performed. However, the skew correction operation may be selected depending on not only the thickness of the paper but also the rigidity of the paper and the type of the paper. Further, the automatic paper feeder may be provided with detection means such as a sensor for detecting the temperature and humidity conditions during paper feed, and the skew correction means may be selected according to the detection result.

  As described above, the automatic paper feeder according to the embodiment of the present invention increases the paper abutting force so that the leading edge of the paper 20 is surely pushed into the nip portion between the pinch roller 29 and the conveying roller 30. Therefore, stable paper biting can be realized with a very simple configuration.

1 is a schematic perspective view showing an entire recording apparatus including an automatic paper feeder of the present invention. FIG. 2 is a schematic top view showing the entire recording apparatus of FIG. 1. FIG. 2 is a schematic cross-sectional view showing a cross section of the recording apparatus of FIG. 1. FIG. 2 is a schematic perspective view showing a drive transmission unit of the recording apparatus of FIG. 1. It is a disassembled perspective view which shows the structure of the periphery of the sun gear of the drive transmission part of the recording device of FIG. It is sectional drawing which shows the structure and operation | movement of a drive transmission part. It is sectional drawing which shows the structure and operation | movement of a drive transmission part. It is sectional drawing which shows the structure and operation | movement of a drive transmission part. It is sectional drawing which shows the structure and operation | movement of a drive transmission part. It is sectional drawing which shows the structure and operation | movement of a drive transmission part. It is a disassembled perspective view of a separation roller. It is sectional drawing of a separation roller. 3 is a timing chart showing the operation of the automatic paper feeder of the present invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. It is typical sectional drawing which shows the action | operation of the automatic paper feeder of this invention. FIG. 11B is an enlarged view of FIG. 11A. It is an enlarged view of FIG. 11B. It is typical sectional drawing which shows the action | operation of the conventional automatic paper feeder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feeder 10 Paper feed shaft 11 Feed roller 12 Separation roller 19 Paper feed gear 20 Paper 30 Carrying roller 38 Sun gear 39 First planetary gear 40 First planetary arm 43 Trigger arm 44 Second planetary arm 45 First 2 planetary gear

Claims (10)

With sun gear,
First and second planetary gears engaged with the sun gear;
The first planetary gear is coupled to the sun gear and the first planetary gear, and the first planetary gear is rotated around the sun gear when the sun gear rotates in a first rotational direction. A first planetary arm that rotates in a direction;
Coupled to the sun gear and the second planetary gear, when the sun gear rotates in a second direction of rotation, the second planetary gear is moved around the sun gear around the second rotation. A second planetary arm that rotates in a direction;
A control gear that engages with the first planetary gear by rotation of the first planetary arm and transmits torque only in a rotational direction corresponding to the first rotational direction;
A paper feed gear that engages with the control gear and that also engages with the second planetary gear by rotation of the second planetary arm;
A regulating member that regulates the rotation of the first and second planetary arms;
A feeding roller driven by the paper feeding gear;
In conjunction with the sun gear, a conveyance roller provided downstream of the feeding roller in the paper conveyance direction;
An automatic paper feeder.   2. The automatic control gear according to claim 1, wherein the control gear has an engagement portion on a side surface that holds the engagement between the first planetary gear and the control gear by the engagement of the first planetary gear. Paper feeder.   The automatic feeding device according to claim 1, wherein the control gear includes a one-way clutch as means for transmitting torque only in a rotation direction corresponding to the first rotation direction.   A recording apparatus comprising the automatic paper feeder according to any one of claims 1 to 3. The restriction member cancels the rotation restriction of the first planetary arm, and the sun gear rotates in the first direction, whereby the first planetary gear is engaged with the control gear, and the supply gear A first transport mode in which a feed roller is rotated in the paper transport direction via the control gear, and the transport roller rotates in the paper transport direction in conjunction with the sun gear;
The restriction member releases the rotation restriction of the second planetary arm, and the sun gear rotates in the second direction, whereby the second planetary gear is engaged with the paper feed gear, A second transport mode in which the feed roller is rotated in the paper transport direction, and the transport roller is rotated in the paper reverse transport direction in conjunction with the sun gear;
The restricting member restricts the rotation of the second planetary arm to prevent the feeding roller from rotating, the sun gear rotates in the second direction, and the transport roller and the sun gear A third transport mode that rotates in conjunction with the paper reverse feed direction;
The recording apparatus according to claim 4, further comprising a control unit that selectively executes. The controller is
A first skew correction operation in which a sheet is sandwiched between the conveyance rollers in the first conveyance mode and then reversely conveyed in the third conveyance mode while the sheet is held by the feeding roller;
After the sheet is transported to the upstream side in the transport direction of the transport roller in the first transport mode, a second skew correction operation that abuts against the transport roller in the second transport mode is selectively executed. The recording apparatus according to claim 5. Having at least one of detection means of rigidity, thickness, type, ambient humidity or ambient temperature of the paper;
The recording apparatus according to claim 6, wherein the control unit selects one of the first and second skew correction operations according to a detection result of the detection unit.   The recording apparatus according to claim 5, wherein the control unit switches the rotation restricting operation of the restricting member by controlling contact of a carriage member with the restricting member. A first planetary gear engaged with a sun gear rotates the sun gear in a first direction, and a first planetary arm connected to the sun gear and the first planetary gear moves the first planetary gear to the first gear. An engagement step of rotating about the sun gear by rotating in a direction to engage the first planetary gear with the control gear;
The sun gear is further rotated in the first direction, the paper feed gear engaged with the control gear is rotated, and the feed roller connected to the paper feed gear is rotated in the paper transport direction. A feed roller rotation step;
Transporting the fed paper by the rotating feed roller, and sandwiching it between transport rollers located downstream of the feed roller in the paper transport direction;
Rotation of the control gear is prevented by a one-way clutch means incorporated in the control gear, and while the paper is held by the feed roller, the transport roller is rotated in the paper reverse feed direction to A first skew correction operation comprising a step of reversely feeding the sandwiched paper;
The engaging step;
The feeding roller rotating step;
Transporting the fed paper to the front of the transport roller by the rotating feed roller;
After the paper is transported to the front of the transport roller, the second planetary gear engaged with the sun gear is rotated in the second direction so that the sun gear and the second planetary gear are rotated. Rotating the second planetary arm coupled to the second gear by rotating in the second direction to engage the second planetary gear with the paper feed gear;
The sun gear is further rotated in the second direction while the conveying roller is rotated in the direction in which the sheet is reversely fed, and the feeding roller is rotated in the sheet conveying direction to convey the sheet. A second skew correction operation having a step of conveying until it hits the roller;
Is a method for controlling the automatic paper feeder. Detecting at least one of stiffness, thickness, type, ambient humidity or ambient temperature of the paper;
Selectively executing one of the first and second skew correction operations based on the detection result in the detection step;
The method of controlling an automatic paper feeder according to claim 9.

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