JP2011056846A - Medium feeder and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medium feeder giving consideration to stabilize a posture of a medium to be fed in a feeding direction. <P>SOLUTION: The medium feeder (3) includes: a movable guiding part 6 disposed outside a curved section R of medium guiding paths (11, 12), and configured to switch the posture thereof between a first state to narrow the thickness direction Z of the medium (P) to be fed in the space of the paths and a second state to enlarge the thickness direction larger than that in the first state; a first switching means 5 for switching between the first state and the second state of the movable guiding part. The first state of the movable guiding part 6 is maintained until the leading end of the medium (P) to be fed passes through the movable guiding part 6, and prior to perform an operation of making the posture of the leading end of the medium (P) to be fed match with a line direction formed by circumscribing portions of a pair of conveying rollers 71, the first state of the movable guiding part 6 is switched to the second state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a feeding unit that feeds a medium to be fed to the downstream side in the feeding direction, and a conveyance roller that is arranged on the downstream side in the feeding direction from the feeding unit and that conveys the medium to be fed sent by the feeding unit to the downstream side in the feeding direction. A medium feeding device having a pair and a medium guide path portion that has a section curved in side view and guides a medium to be fed from the feeding means to the pair of conveying rollers, and recording provided with the medium feeding device Relates to the device.
In the present application, the recording apparatus includes types such as an ink jet printer, a wire dot printer, a laser printer, a line printer, a copying machine, and a facsimile.

  Conventionally, as shown in Patent Document 1, a printer that is an example of a recording apparatus has a feeding device that feeds a sheet that is an example of a medium to be fed. The feeding device has feeding means, a pair of conveying rollers, and a guide portion as a medium guide path portion. Among these, the feeding means is provided so that the paper can be fed to the downstream side in the feeding direction. Further, the transport roller pair is provided on the downstream side in the feed direction with respect to the feed means, and is provided so that the paper can be further transported downstream in the feed direction.

Still further, the guide portion is formed so as to be able to guide the paper from the feeding means to the pair of transport rollers. In addition, the guide portion has a section that is curved in a side view, and has a flap portion that can swing outside the curved section. The flap portion was biased from the outside to the inside of the curved section by the spring force.
Then, when the feeding means feeds the paper to the pair of transport rollers, a so-called skew removing operation is performed to correct the posture of the paper with respect to the paper feeding direction.

Specifically, between the transport roller pair and the feeding means, the paper is bent and the leading edge of the paper is pressed against the circumscribed portion of the transport roller pair. As a result, the posture of the leading edge of the paper is made to follow the nip line of the pair of conveying rollers.
Here, the “nip line” refers to a line formed by a circumscribed portion of the roller pair. That is, it is a line formed by a pinching portion in the roller pair.
When the sheet is bent, the sheet is bent while the flap portion is pushed outward against the spring force.

JP-A-8-157107

  However, after the skew removal operation, the flap portion is biased so as to press the portion where the paper is bent by the spring force, so that the posture of the paper with respect to the feeding direction may be inclined. Specifically, if the leading edge of the paper is tilted with respect to the nip line in the previous stage of the skew removal operation, the amount of deflection on one end side in the width direction of the paper and the other end side after the skew removal operation There is a difference in the amount of bending.

  Here, the bending of the sheet acts so as to push the sheet to the downstream side in the feeding direction in the pair of transport rollers. In the prior art, the flap portion urges only one of the large deflection amounts in the left and right sides of the sheet in the width direction to the side that reduces the deflection of the sheet, which may adversely affect the conveyance accuracy of the pair of conveyance rollers. . Specifically, since only one of the left and right sides in the width direction is urged, there is a possibility that the conveyance amount of the one becomes larger than the conveyance amount of the other and the posture of the sheet is inclined.

  Further, even when the amount of bending of the sheet in the left and right sides in the width direction is substantially the same, there is a possibility that the conveyance accuracy in the pair of conveying rollers may become unstable due to the flap portion biasing the portion where the sheet is bent. is there. Specifically, since the urging force changes depending on the amount of expansion and contraction of the spring, the action and influence of the flap portion on the bent position of the paper also change, and the conveyance accuracy may become unstable.

Furthermore, since the flap portion is urged by a spring force, there is a possibility that a space sufficient for deflecting the sheet cannot be secured if the spring force is relatively strong. In such a case, there is a possibility that sufficient skew removal cannot be executed.
Further, in the previous stage of the skew removal operation, the flap portion is pushed up to the outside of the curved section against the spring force by the leading edge of the sheet being fed, and enters the path of the leading edge of the sheet in the lateral direction. There may be a difference. In such a case, the posture of the leading edge of the sheet is a factor that tilts with respect to the nip line. That is, it causes a skew.

  The present invention has been made in view of such a situation, and its problem is to provide a medium feeding device that takes into account the stabilization of the posture of the medium to be fed in the feeding direction, and a recording apparatus including the medium feeding device. Is to provide.

  In order to achieve the above object, a medium feeding device according to a first aspect of the present invention includes a feeding unit that feeds a medium to be sent to a downstream side in a feeding direction, and a downstream side in the feeding direction from the feeding unit. A transport roller pair for transporting the transported medium to the downstream side in the transport direction, and a medium guide path section having a section that is curved in side view and guiding the transported medium from the transport means to the transport roller pair. The medium guide path portion is provided outside the curved section, and can be switched between a first state in which the thickness direction of the medium to be fed is narrowed in the path space and a second state in which the thickness direction is wider than the first state. A movable guide portion; and a first switching means for switching between the first state and the second state of the movable guide portion, and when the medium to be fed is sent downstream in the feed direction by the feed means, Medium A medium feeding device configured to perform an operation of copying the posture of the tip that is the downstream end in the feeding direction in a line direction formed by a circumscribed portion of the pair of conveying rollers, the medium feeding device comprising: Until the leading edge passes through the movable guide part, the first state of the movable guiding part is maintained, and the operation of causing the posture of the tip of the medium to be fed to follow the linear direction of the transport roller pair is executed. The movable guide unit is configured to switch to the second state.

Here, “a line formed by a portion where the conveying roller pair circumscribes” is a so-called nip line of the conveying roller pair.
In addition, the “operation for copying the posture of the tip of the medium to be fed in the direction of the line formed by the circumscribed portion of the conveying roller pair” refers to an operation for correcting the posture of the tip of the medium to be fed. This is a so-called skew removal operation. The skew removing operation may be a so-called “breaking-out discharge method” or “butting method”.

  Here, in the “biting discharge method”, the transport roller pair once clamps the leading end of the medium to be transported, and the transport roller pair is reversed to reversely feed the front end side of the transported medium upstream in the feed direction. Then, between the feeding means and the pair of transport rollers, a method of deflecting the medium to be fed and pressing the tip of the medium to be fed against the nip line of the pair of transport rollers to follow the posture of the tip to the nip line. . In other words, once the leading edge of the medium to be fed is bitten by the pair of transport rollers, the leading medium side is deflected by discharging the leading edge of the medium to be fed upstream in the feeding direction so that the posture of the leading edge follows the nip line. This method is used.

  On the other hand, the “abutment method” means that the medium to be fed is sent to the downstream side in the feeding direction by the feeding means, and the leading edge of the medium to be fed is brought into contact with the nip line of the conveying roller pair in a stopped state or a reverse driving state. This is a method of making the tip posture follow the nip line by pressing. That is, it refers to a system in which the tip of the medium to be fed is brought into contact with a pair of conveying rollers so that the posture of the tip follows the nip line. Of course, the medium to be fed is bent between the feeding means and the pair of conveying rollers so that the posture of the leading end follows the nip line.

According to the first aspect of the present invention, since the first state is maintained when guiding the leading end of the medium to be fed, the difference in the path of the leading end of the medium to be fed between the left and right in the width direction of the medium to be fed is minimized Can be small. Accordingly, it is possible to reduce a so-called skew in which the posture of the medium to be fed is inclined with respect to the feeding direction. Specifically, the inclination of the tip of the medium to be fed with respect to the nip line can be reduced.
Further, the state of the movable guide portion is switched by the first switching means, and the first state can be maintained, so that the movable guide portion is greatly increased by the tip of the medium to be fed as in the configuration of the prior art. There is no risk of being pushed up.

Furthermore, when performing the skew removal operation thereafter, a space for bending the medium to be fed can be ensured between the feeding means and the pair of transport rollers. That is, as compared with the configuration of the prior art, the biasing force to the medium to be fed by the spring or the like does not act, so that a space for bending the medium to be fed can be ensured. Accordingly, the leading end of the medium to be fed can be reliably pressed against the nip line of the pair of conveying rollers by the bending of the medium to be fed. As a result, the attitude of the leading end of the medium to be fed can be made to closely follow the nip line.
Further, since the urging force against the medium to be fed by the spring or the like does not act, there is no possibility that the urging force adversely affects the conveyance accuracy.

According to a second aspect of the present invention, in the first aspect, after the movable guide portion is switched to the second state, a rear end that is an upstream end in the feed direction of the medium to be fed passes through the movable guide portion. Is configured to maintain the second state.
According to the second aspect of the present invention, in addition to the same effect as the first aspect, the second state is maintained until the rear end of the medium to be fed passes through the movable guide portion. There is no possibility of adversely affecting the medium to be fed in a state where the guide portion is bent. Specifically, there is no possibility that the biasing force to the medium to be fed by the spring or the like in the configuration of the prior art acts.

  Here, if an urging force is applied, it acts to push the fed medium in a bent state to the downstream side or the upstream side in the feed direction. And there is a possibility that it may have a bad influence on the force which conveys the medium to be fed to the downstream side in the feeding direction by the pair of carrying rollers. That is, when the urging force is applied, the conveyance by the conveyance roller pair may become unstable, and the conveyance accuracy may be reduced. When there is a difference in the amount of bending of the medium to be fed in the left and right in the width direction, it acts to strongly press the side with the larger amount of bending. Then, there is a possibility of acting so that the posture of the medium to be fed is inclined with respect to the feeding direction. In this aspect, there is no risk of such adverse effects.

  According to a third aspect of the present invention, in the first or second aspect, the feeding unit is a pair of feeding rollers having a feeding driving roller that is driven by power and a feeding driven roller that is driven to rotate, and the conveying roller. The pair includes a conveyance driving roller that is driven by power and a conveyance driven roller that is driven to rotate, and the medium feeding device relatively moves the feeding driving roller and the feeding driven roller of the pair of feeding rollers. And a second switching means for switching between a state in which the feed driving roller and the feed driven roller are close to each other and a state in which the feed driven roller is separated from each other, and the movable guide portion is switched to the second state. After the posture of the front end of the medium is made to follow the linear direction, the front end of the medium to be fed is transported by driving the transport driving roller to rotate forward. In a state of being sandwiched between roller pairs, the feed roller pair is switched to the separated state, and the feed drive roller is driven to rotate forward so that the medium to be fed follows the outside of the medium guide path portion. It is characterized by.

  According to the third aspect of the present invention, in addition to the same effects as those of the first or second aspect, the feeding roller pair is separated from the separation roller in a state where the leading end of the medium to be fed is sandwiched between the conveying roller pair. To the state. Therefore, it is possible to follow the posture of the rear end side of the medium to be fed in the same manner as the front end. At this time, there is a possibility that the amount of deflection on both sides in the width direction of the medium to be fed remains different between the pair of feed rollers and the pair of transport rollers in the feed direction. That is, there is a possibility that the left and right deflection amounts are still in a state of difference.

  Therefore, in this aspect, the driving roller to be fed is driven to rotate forward. At this time, since the feed roller pair is in the separated state, an appropriate feed force can be applied while easily generating a slip between the feed drive roller and the medium to be fed. Therefore, the medium to be fed can be bent appropriately within the area guided by the medium guide path. As a result, the amount of bending of the medium to be fed can be made substantially uniform in the width direction, and the difference in the amount of bending on both sides of the medium to be fed can be eliminated. Then, it is possible to prevent the so-called cumulative skew from occurring due to the difference between the left and right deflection amounts during the subsequent conveyance. That is, by removing the difference in the force by which the medium to be fed is pushed downstream in the feeding direction due to the difference between the left and right bending amounts, the posture of the medium to be fed can be stabilized during the conveyance.

Further, in this aspect, the feeding medium is moved away from the feeding driving roller by driving the feeding driving roller in the normal direction.
Here, if the feed drive roller is reversely driven, the fed medium behaves so as to be wound around the feed drive roller.
Therefore, in this aspect, it is possible to reduce the rotational load of the feed drive roller as compared with the case where the feed drive roller is reversely driven.

  According to a fourth aspect of the present invention, in the third aspect, the transport driving roller and the feed driving roller are driven after the transport driving roller is driven to rotate forward so that the tip of the medium to be fed is sandwiched between the transport roller pair. In which the speed of the outer periphery of the feed drive roller at this time is faster than the speed of the outer periphery of the transport drive roller. And

According to the fourth aspect of the present invention, in addition to the same effects as the third aspect, the feed drive roller is moved at a speed faster than the outer peripheral speed of the transport drive roller while driving the transport drive roller in the normal direction. Drive. Therefore, the timing at which the pair of transport rollers feeds the medium to be transported to the downstream side in the feed direction can be made faster than in the configuration in which the feed drive roller is driven to rotate forward while the transport drive roller is stopped.
Furthermore, since the feed driving roller is driven at a speed faster than the outer peripheral speed of the transport drive, the medium to be fed can be appropriately bent between the transport drive roller pair and the feed drive roller.

  Furthermore, the relative speed difference between the speed of the transport drive roller and the speed of the feed drive roller is reduced as compared to the configuration in which the transport drive roller is driven to rotate forward with the transport drive roller stopped. Is possible. Accordingly, it is possible to relatively reduce the amount of slip generated between the medium to be fed and the feed driving roller. As a result, it is possible to reduce the slip noise as compared with the configuration in which the feed drive roller is driven to rotate in the forward direction while the transport drive roller is stopped.

A recording apparatus according to a fifth aspect of the present invention includes a medium feeding unit that sends a recording medium downstream in the feeding direction, a recording unit that records the recording medium sent by the medium feeding unit by a recording head, The medium feeding means comprises the medium feeding device according to any one of the first to fourth aspects, and the recording medium is the medium to be fed. And
According to a fifth aspect of the present invention, the medium feeding means includes the medium feeding device according to any one of the first to fourth aspects. Therefore, in the recording apparatus, it is possible to obtain the same function and effect as in any one of the first to fourth aspects.

FIG. 4 is a side view illustrating an operation during pickup in the printer according to the invention. FIG. 3 is a side view showing an operation during bank separation in the printer according to the present invention. FIG. 4 is a side view showing an operation of retard separation inside the printer according to the invention. FIG. 6 is a side view showing an operation after retard separation in the printer according to the invention. FIG. 6 is a side view showing an operation after retard separation in the printer according to the invention. The side view which shows the initial biting state in the case of the skew removal which concerns on this invention. The side view which shows the discharge state in the case of the skew removal which concerns on this invention. The side view which shows the cueing state in the case of skew removal which concerns on this invention. The side view which shows the normal rotation operation | movement after the skew removal which concerns on this invention. The side view which shows a mode that the subsequent paper is picked up in this invention. The schematic side view which shows the structure of the 1st switching means of this invention. (A) (B) is a side view which shows the 1st state and 2nd state of a movable guide part. The figure which shows the timing which switches the state of the movable guide part of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an operation at the time of pickup in an ink jet printer (hereinafter referred to as “printer”) 1 as an example of a “recording apparatus” or a “liquid ejecting apparatus”.
Here, the liquid ejecting apparatus refers to an ink jet recording apparatus, a copying machine, a facsimile, or the like that performs recording on a recording material by ejecting ink from a recording head as a liquid ejecting head to a recording material such as recording paper. In addition to the recording apparatus, instead of ink, a liquid corresponding to a specific application is ejected from the liquid ejecting head corresponding to the recording head to the ejected material corresponding to the recording material, and the liquid is ejected to the ejected material. Used to include the device to be attached.

  Further, as the liquid ejecting head, in addition to the recording head described above, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material used for forming an electrode such as an organic EL display or a surface emitting display (FED). (Conductive paste) A jet head, a bio-organic matter jet head used for biochip manufacturing, a sample jet head for jetting a sample as a precision pipette, and the like.

  As shown in FIG. 1, the printer 1 includes a feeding unit 3 as a feeding device that feeds paper P, a recording unit 80, and a discharge unit (not shown). Among these, the feeding unit 3 includes a feeding unit 10 and a conveying unit 70. The feeding unit 10 includes a pickup unit 20, a preliminary separation unit 30, and a main separation unit 40. The pickup unit 20 is provided so that the paper P placed on the cassette unit 14 can be picked up and sent downstream in the feed direction.

  Specifically, it includes a pickup roller 21 that is driven by the power of a first motor 91 that is an example of a drive source, and an arm portion 22 that holds the pickup roller 21 and swings around an arm shaft 23 as a fulcrum. The pickup roller 21 is biased in a direction approaching the paper P by a biasing means (not shown). Further, the arm 22 is swung by a pickup retracting means (not shown) so that the pickup roller 21 can be moved away from the paper P on which the pickup roller 21 is placed. This is a so-called pickup release operation.

Further, the preliminary separation unit 30 includes a bank separation unit 31 that performs so-called bank separation. The operation will be described later.
Furthermore, the main separation unit 40 is provided on the downstream side in the feed direction of the preliminary separation unit 30. The separation unit 40 includes a so-called retard roller 41 that is rotated by a predetermined load. The retard roller 41 is provided so as to make a pair with the intermediate drive roller 50 driven by the power of the first motor 91. The retard roller 41 is provided to be movable toward and away from the intermediate drive roller 50 by the swing mechanism 43. Specifically, the swing mechanism 43 is configured to hold the retard roller 41 by a retard holder (not shown) and swing around a swing shaft (not shown).

  One end of the urging spring (not shown) is engaged with the base portion 2, and the other end is engaged with the free end side of the retard holder (not shown). Therefore, the retard roller 41 can be urged toward the intermediate drive roller 50. The swing mechanism 43 is a cam portion 45 that is driven by the power of the second motor 92 as means for moving the retard roller 41 away from the intermediate drive roller 50 against the biasing force of a biasing spring (not shown). have. The cam portion 45 is engaged with a convex portion (not shown) of a retard holder (not shown) to form a groove cam mechanism 8, and the retard roller 41 is moved to the intermediate drive roller 50 via the retard holder (not shown). So that they can be moved apart.

Further, a first assist roller 48 that is driven to rotate is provided between the bank separation unit 31 and the retard roller 41. The first assist roller 48 is provided so that the leading edge of the paper P that has passed through the bank separation unit 31 can be smoothly guided to the nip point N between the retard roller 41 and the intermediate drive roller 50.
Furthermore, on the downstream side in the feed direction from the nip point N between the retard roller 41 and the intermediate drive roller 50, paper front end regulating ribs 60, 60 described later are provided.

Further, on the downstream side in the feed direction, a second assist roller 51 that is rotatably held by the base portion 2 and circumscribes the intermediate drive roller 50 is provided. The second assist roller 51 is configured to form a feed roller pair 96 as a feed means together with the intermediate drive roller 50.
The feed roller pair 96 is included in the configuration of the feeding unit 10.

Here, the feeding path of the paper P is formed in a U-shaped side view from the pickup unit 20 to the conveyance unit 70. Specifically, a U-shaped outer sheet guide unit 11 that guides the sheet P from the outside of the U-shape, an inner sheet guide unit 12 that guides the sheet P from the inside, a bank separation unit 31, and an entrainment prevention unit 13 that will be described later. A U-shaped feed path is configured by.
Therefore, the frictional resistance generated between the paper P and the U-shaped outer paper guide portion 11 of the base portion 2 by the first assist roller 48 and the second assist roller 51 can be reduced. Accordingly, it is possible to smoothly feed the paper P to the transport unit 70 on the downstream side in the feeding direction.

Further, a movable guide portion 6 is provided on the downstream side of the feed roller pair 96 in the feed direction. The movable guide portion 6 constitutes a part of the U-shaped outer sheet guide portion 11 and is configured to be switched between a first state and a second state by a first switching means 5 described in detail later.
Here, the first state of the movable guide portion 6 means a state where the thickness direction Z of the paper P in the feeding path can be narrowed as shown in FIG. On the other hand, the second state of the movable guide portion 6 means a state in which the thickness direction Z of the paper P in the feed path can be made wider compared to the first state, as shown in FIGS. .

  The movable guide portion 6 is provided so that the downstream side in the feed direction can swing with the support shaft portion 7 as a fulcrum. As will be described in detail later, in the first state, by narrowing the space in the thickness direction Z of the paper P in the feed path between the feed roller pair 96 and the transport roller pair 71, the leading edge of the paper P is accurately fed in the feed direction. Guide to the downstream side. In the second state, the space in the thickness direction Z can be made wider than that in the first state in the feed path between the feed roller pair 96 and the transport roller pair 71, and the paper P can be bent. A can be secured sufficiently.

A plurality of intermediate drive rollers 50 and second assist rollers 51 constituting the feed roller pair 96 are provided in the width direction X. This is because a sufficient feeding force is applied to the paper in the side-view U-shaped path, and the paper P is reliably sent downstream in the feeding direction.
The transport unit 70 includes a transport roller pair 71 that transports the paper P. The transport roller pair 71 includes a transport drive roller 72 that is driven by the power of the fourth motor 94 and a transport driven roller 73 that is driven to rotate. Among these, the conveyance driven roller 73 is rotatably held by a driven roller holder 74.
Further, the driven roller holder 74 presses the transport driven roller 73 against the transport driving roller 72 by an urging means (not shown).

  Furthermore, in the feed direction Y, a paper detector 75 that detects the presence or absence of the paper P is provided in the vicinity of the upstream side of the transport roller pair 71. Specifically, the paper detector 75 includes a swingable paper detection lever 77 and a sensor unit 76. Then, one end of the paper detection lever 77 is swung by coming into contact with the paper P, and the other end of the paper detection lever 77 is separated from a light emitting unit and a light receiving unit (not shown) of the sensor unit 76 to be turned on. It is comprised so that it may become.

Further, the transport unit 70 is provided so that the paper P can be transported to the recording unit 80 provided on the downstream side in the feed direction.
The recording unit 80 further includes a recording head 82 that performs recording by ejecting ink onto the paper P, and a medium support unit 81 that faces the recording head 82 and supports the paper P from below.
Thereafter, the recorded paper P is discharged to a discharge tray (not shown) on the front surface of the printer 1 by a discharge roller of a discharge unit (not shown).

Next, a more detailed paper feeding operation will be described.
As shown in FIG. 1, when picking up the uppermost sheet P1 with respect to the pickup roller 21 placed on the cassette unit 14, the control unit 90 swings the arm unit 22 to move the pickup roller 21 to the uppermost sheet. Contact with P1. Then, by driving the third motor 93, the pickup roller 21 is rotated clockwise in the figure.

  At this time, the pickup roller 21 is urged in a direction approaching the paper P by an urging means (not shown). Accordingly, a frictional force is generated between the pickup roller 21 and the uppermost sheet P1, and a feeding force that is a force fed downstream in the feeding direction can be generated. Then, the uppermost sheet P1 starts to move downstream in the feeding direction by the feeding force. That is, it is picked up and sent downstream.

Note that the friction coefficient μ1 between the pickup roller 21 and the uppermost sheet P1, the friction coefficient μ2 between the sheet P and the sheet P, and the pad portion 15 provided at a position facing the pickup roller 21 on the base unit side. When the friction coefficient μ3 between the paper and the paper P is set, the relationship of friction coefficient μ1> friction coefficient μ3> friction coefficient μ2 is established. Accordingly, it is possible to reduce the so-called double feed risk in which several sheets of paper P are fed in an overlapping manner.
Further, when picked up, the retard roller 41 is close to the intermediate drive roller 50.

FIG. 2 is a side view showing the operation at the time of bank separation inside the printer according to the present invention.
As shown in FIG. 2, the paper P picked up by the pickup roller 21 is sent downstream in the feed direction. Then, the fed paper P enters the bank separation unit 31 as the preliminary separation unit 30.

Here, the feeding force is also applied to the succeeding and subsequent sheets P2 by the friction coefficient μ2 between the uppermost sheet P1 and the succeeding and subsequent sheets P2 with respect to the pickup roller 21 and the urging force that urges the pickup roller 21. May occur.
In such a case, not only the uppermost sheet P1 but also the subsequent sheet P2 is fed to the downstream side in the feeding direction by the pickup roller 21.

  Therefore, in order to separate the second and subsequent sheets P2 that have been multi-fed from the uppermost sheet P1, the sheet P is caused to enter the bank separation unit 31 provided at an angle at which the posture of the leading end of the sheet P is displaced. Then, by applying the leading edge of the paper P to the bank separation unit 31, a trigger for stopping the subsequent paper P <b> 2 is created. Furthermore, a gap can be provided between the uppermost sheet P1 and the subsequent sheet P2. Therefore, the next and subsequent sheets P2 that are double-fed can be separated from the uppermost sheet P1.

FIG. 3 is a side view showing the operation of retard separation inside the printer according to the present invention.
As shown in FIG. 3, the paper P separated by the bank separation unit 31 is further fed downstream in the feeding direction by the pickup roller 21. Then, the paper P is sent to a nip point N where the retard roller 41 which is the main separation unit 40 and the intermediate drive roller 50 are circumscribed.
In the present embodiment, since the preliminary separation unit 30 is merely a preliminary separation unit, it is assumed that several sheets P may be double-fed to the main separation unit 40. Hereinafter, description will be made on the assumption that several sheets of paper P are double-fed.

When the multi-feed paper P is sent to the nip point N, only the uppermost paper P 1 is in direct contact with the intermediate drive roller 50 with respect to the intermediate drive roller 50. Further, the leading edge of the paper P2 after the next is in contact with the retard roller 41 with a predetermined load for rotation.
Here, the friction coefficient μ4 between the intermediate drive roller 50 and the uppermost sheet P1, the friction coefficient μ2 between the sheet P and the sheet P, and the friction coefficient μ5 between the retard roller 41 and the sheet P are set. , Friction coefficient μ4> friction coefficient μ2, and friction coefficient μ5> friction coefficient μ2.

Accordingly, the feeding force acting on the uppermost sheet P1 can be made larger than the feeding force acting on the subsequent sheet P2.
Here, the load of the retard roller 41 is configured to be larger than the feeding force acting on the succeeding and subsequent sheets P2.
Accordingly, by rotating the intermediate drive roller 50 in the clockwise direction in the drawing, only the uppermost sheet P1 can be sent downstream in the feed direction.

  More specifically, the leading edge of the succeeding sheet P2 is held at the nip point N by the load of the retard roller 41, and slip occurs between the uppermost sheet P1 and the next sheet P2. Can do. Accordingly, the uppermost sheet P1 can be separated from the subsequent sheet P2 and sent downstream in the feed direction. The leading end of the uppermost sheet P1 passes through the second assist roller 51 and reaches the movable guide unit 6 while being guided by the U-shaped outer sheet guide unit 11 and the inner sheet guide unit 12.

  Here, the movable guide portion 6 in the first state is held with a slight play (see FIG. 12A). Further, until the leading edge of the paper P1 arrives, the downstream side 6a in the feed direction of the movable guide 6 is lowered by its own weight within the range of play. When the leading edge of the paper P1 reaches the movable guide portion 6, the play of the paper P1 causes the leading edge of the paper P1 to resist the play guide downstream 6a on the downstream side 6a of the movable guide portion 6 against its own weight. Push up slightly in the range of. Here, the stiffness of the paper refers to the elasticity and rigidity of the paper. That is, a minimum space through which the sheet can pass is generated in the sheet thickness direction Z in the feeding path.

  Therefore, the difference in the position in the thickness direction Z of the paper P at the front end of the paper P can be made as small as possible on the left and right in the width direction of the paper P. The difference in the path drawn by the leading edge of the paper P on the left and right in the width direction of the paper P can be made as small as possible. As a result, the inclination of the leading edge of the paper P1 with respect to the so-called nip line, which is a line (line in the X-axis direction) formed by the circumscribed portion of the transport roller pair 71, can be made as small as possible. In other words, the inclination of the entire sheet with respect to the feeding direction Y of the sheet P1 can be made as small as possible before the skew removing operation described later.

  That is, the inclination of the leading edge of the sheet P1 with respect to the nip line can be reduced as compared with the case where the movable guide portion 6 is not in the first state. Further, the inclination of the leading edge of the sheet P1 with respect to the nip line can be reduced as compared with the configuration in which the flap in the conventional technique is biased downward by the spring force. This is because, in the prior art, when the leading edge of the sheet passes, the leading edge of the sheet resists the spring force and pushes the flap upwards by the stiffness of the sheet, thereby expanding the space in the thickness direction Z of the sheet.

Further, by providing the play range, it is possible to deal with paper P having a different thickness.
Of course, the first state of the movable guide 6 may be configured without providing the play range. In the present embodiment, the reason for providing the play range is that after the surface of the paper P is recorded, the paper P is reversely fed upstream in the feeding direction during recording, and the paper P is turned upside down by a front / back turning mechanism (not shown). This is because it is necessary to pass the paper P over the movable guide portion 6 in order to guide the paper P to the front / back reversing mechanism.

That is, when the paper is fed backward, the weight of the movable guide unit 6 closes the space between the downstream side 6a of the movable guide unit 6 in the feeding direction and the inner sheet guide unit 12, and the sheet P is moved from the movable guide unit 6 to the inner sheet. This is to prevent entry into the guide portion 12.
Therefore, the play range need not be provided as long as the structure is not reversed. A state in which the space between the downstream side 6a in the feeding direction of the movable guide 6 and the inner sheet guide 12 is slightly opened may be the first state of the movable guide 6.

FIG. 4 is a side view showing the operation after the retard separation in the printer according to the present invention.
As shown in FIG. 4, when the uppermost sheet P1 is further fed to the downstream side in the feeding direction with respect to the intermediate drive roller 50, the leading edge of the uppermost sheet P1 is detected by the sheet detector 75. Specifically, the leading end of the uppermost sheet P1 comes into contact with one end of the sheet detection lever 77, and the sheet detection lever 77 is swung. At this time, since the other end of the paper detection lever 77 is disengaged from between the light emitting part and the light receiving part of the sensor unit 76, the paper detector 75 is turned on.

Using this as a trigger, the control unit 90 moves the retard roller 41 away from the intermediate drive roller 50. Specifically, the cam portion 45 is rotated by the second motor 92 and the retard holder (not shown) is retracted from the intermediate drive roller 50 against the biasing force of the biasing spring (not shown). Swing in the direction.
Further, the control unit 90 drives the third motor 93 to swing the arm unit 22 around the arm shaft 23 in the direction in which the pickup roller 21 is retracted from the paper P placed on the cassette unit 14.
The timing for starting the separation movement of the retard roller 41 may be when the intermediate drive roller 50 and the pickup roller 21 reach a predetermined rotation amount.

When the retard roller 41 moves away, the uppermost sheet P1 is fed by the intermediate drive roller 50 and the second assist roller 51.
Further, when the pickup roller 21 moves away, the feeding force does not directly act on the subsequent paper P2 from the intermediate drive roller 50 and the pickup roller 21. Therefore, the next and subsequent sheets P2 whose leading ends are held by the retard roller 41 try to return to the cassette unit 14 by their own weight.

However, the trailing edge of the preceding sheet P1, which is the uppermost sheet fed by the intermediate drive roller 50, and the leading edge of the succeeding sheet P2, which is the succeeding and subsequent sheets whose leading edge is held by the retard roller 41, Touch. Accordingly, the feeding force acts indirectly on the succeeding paper P2.
Therefore, convex paper leading edge regulating ribs 60 and 60 are provided on the downstream side in the feed direction from the nip point N between the intermediate drive roller 50 and the retard roller 41 in the U-shaped outer paper guide portion 11. Further, the paper leading edge regulating ribs 60 and 60 are provided in the vicinity of both sides of the retard roller 41 in the width direction X of the paper P.

Since the feed path is bent in a U-shape, when the retard roller 41 moves away, the leading edge of the succeeding paper P2, which is the next and subsequent paper, is displaced toward the U-shaped outer paper guide.
Therefore, after the retard roller 41 moves away, the paper leading edge regulating ribs 60 and 60 come into contact with the leading edge of the succeeding paper P2, which is the next or subsequent paper, and restrict displacement to the downstream side in the feeding direction. it can.

  That is, it is possible to reliably prevent the subsequent paper P2 from being sent downstream in the feed direction. As a result, it is possible to prevent so-called accompanying paper feeding in which the succeeding paper P2 is sent along with the preceding paper P1. The accompanying paper feed is likely to occur when feeding a particularly large size paper P in which the area where the subsequent paper P2 and the preceding paper P1 come into contact with each other is increased. Specifically, it tends to occur in A3 size or larger. In other words, if the size is A4 size or less, the contact area is small, so that there is less possibility of accompanying paper feeding.

At this time, the amount of bending of the succeeding paper P2 can be reduced by moving the pickup roller 21 away. That is, the posture of the succeeding paper P2 can be made as straight as possible. Therefore, the leading edge of the succeeding paper P2 can be positively abutted against the paper leading edge regulating ribs 60, 60.
Further, the trailing edge of the preceding paper P1 acts to push the leading edge of the succeeding paper P2 toward the U-shaped outer paper guide portion that is outside the U-shaped path. Therefore, the leading edge of the succeeding paper P2 can be positively brought into contact with the paper leading edge regulating ribs 60, 60.

As a result, the accompanying paper feeding can be reliably prevented. That is, it is possible to prevent the accompanying paper feeding without providing a so-called return lever provided in the prior art.
Further, the retard roller 41 can be moved away at a timing earlier than that of the prior art. As a result, the so-called back tension due to the load of the retard roller 41 can be reduced at an early timing. For example, when the leading edge of the uppermost sheet P1 reaches the second assist roller 51, the separation roller 41 may start to move away.

FIG. 5 is a side view showing the operation after the retard separation in the printer according to the present invention.
As shown in FIG. 5, when the preceding sheet P1, which is the uppermost sheet with respect to the intermediate drive roller 50 from the state of FIG. 4, is sent downstream in the feed direction, the trailing edge of the preceding sheet P1 is moved to the intermediate drive. Pass between the roller 50 and the retard roller 41.

  Here, an entrainment prevention unit 13 is provided inside the U-shaped path. Specifically, it is provided so as to cover the intermediate drive roller 50 on the upstream side in the feed direction from the nip point N between the intermediate drive roller 50 and the retard roller 41 in the feed direction Y. Therefore, the entanglement prevention unit 13 can prevent the subsequent paper P2 from coming into contact with the intermediate drive roller 50.

As a result, there is no possibility that the intermediate driving roller 50 directly applies the feeding force to the subsequent paper P2.
The leading edge of the preceding paper P1 is nipped by the transport roller pair 71. Thereafter, the movable guide portion 6 is switched to the second state by the first switching means 5 (see FIGS. 11 and 12).

This is to ensure a sufficient space A in which the paper P1 can be bent between the feed roller pair 96 and the transport roller pair 71 in the feed path during the skew removal operation to be performed later. Further, since the leading edge of the paper P1 has already been sandwiched between the transport roller pair 71, there is no reason to leave the space in the thickness direction Z of the paper P in the feed path narrowed.
Thereafter, skew removal is performed, and the preceding sheet P1 is recorded by the recording unit 80 while being conveyed downstream in the feeding direction by the conveying roller pair 71. Then, the paper is discharged to a discharge tray (not shown) in front of the printer 1 by a discharge unit (not shown).

Next, the skew removal operation will be described.
FIG. 6 is a side view showing an initial biting state during skew removal according to the present invention.
As shown in FIG. 6, the control unit 90 first switches the movable guide unit 6 from the first state to the second state by the first switching unit 5. Then, the first motor 91 is driven to rotate forward, and the intermediate drive roller 50 is rotated in the clockwise direction in the drawing. Further, the fourth motor 94 is driven in the normal direction to rotate the transport driving roller 72 in the clockwise direction in the drawing.

Accordingly, as described above, the leading edge of the preceding paper P1 is nipped by the conveyance roller pair 71. Then, the preceding paper P1 is fed until the leading end of the paper P1 is positioned downstream of the conveying roller pair 71 by a predetermined amount.
Here, the posture of the leading edge of the paper P <b> 1 may be inclined with respect to the nip line of the transport roller pair 71. This is so-called skew. The nip line is in the X-axis direction.
Therefore, the following operation is performed to remove the inclination of the sheet P1 with respect to the nip line, so-called skew removal.

FIG. 7 is a side view showing a discharge state during skew removal according to the present invention.
As shown in FIG. 7, the controller 90 stops the first motor 91 and stops the intermediate drive roller 50 from the state of FIG. 6. Further, the fourth motor 94 is switched to the reverse drive, and the transport driving roller 72 is rotated counterclockwise in the drawing. Accordingly, the leading edge of the preceding paper P <b> 1 is fed back to the upstream side of the transport roller pair 71 by the transport roller pair 71. This is a so-called discharge operation.

At this time, the intermediate drive roller 50 is stopped. Accordingly, the preceding paper P1 can be bent between the feed roller pair 96 including the intermediate drive roller 50 and the second assist roller 51 in the feed direction Y and the transport roller pair 71. At this time, since the movable guide portion 6 is in the second state, the bending space A for bending the paper P1 can be sufficiently widened. That is, it is possible to secure the amount of deflection of the paper P1 necessary for the skew removal operation between the feed roller pair 96 and the transport roller pair 71.
The leading edge of the preceding paper P1 can be made to follow the nip line of the transport roller pair 71.

Here, when the sheet P1 is inclined with respect to the nip line in the state shown in FIG. 6, one end side in the width direction X of the sheet P1 is greatly bent as shown by a solid line in FIG. The other end side in the direction X is slightly bent. Further, the magnitude of the difference between the one end side and the other end side in the width direction X of the paper P1 is proportional to the magnitude of the inclination of the leading edge of the paper in the state shown in FIG. That is, the magnitude of the difference between the amount of deflection on one end side in the width direction of the paper P1 and the amount of deflection on the other end side is the position on the one end side in the width direction X at the leading end of the paper P1 and the position on the other end side. Is proportional to the magnitude of the difference.
If the sheet P1 is not inclined with respect to the nip line in the state shown in FIG. 6, the one end side and the other end side in the sheet width direction X in FIG. That is, there is no difference between the amount of bending on one end side in the width direction of the paper P1 and the amount of bending on the other end side.

  Further, as described above, the movable guide portion 6 is set to the first state before the skew removal operation is performed. Therefore, the inclination of the leading edge of the sheet P1 with respect to the nip line of the conveying roller pair 71 in the previous stage of executing the skew removal operation can be made smaller than when the movable guide portion is not in the first state. . Accordingly, as compared with the case where the movable guide portion is in the second state when the leading edge of the paper passes through the movable guide portion, the amount of deflection on one end side on the left and right sides in the width direction of the paper P1 and the other end side are compared. The difference from the amount of deflection can be reduced. As a result, it is possible to reduce the bending space A as compared with the case where the movable guide portion is not in the first state in the previous stage of executing the skew removal operation.

FIG. 8 is a side view showing a cueing state at the time of skew removal according to the present invention.
As shown in FIG. 8, from the state of FIG. 7, the control unit 90 rotates the first motor 91 in the normal direction to rotate the intermediate drive roller 50 in the clockwise direction in the drawing. Further, the fourth motor 94 is driven in the normal direction to rotate the transport driving roller 72 in the clockwise direction in the drawing. Therefore, the leading end of the sheet P1 that is not inclined with respect to the nip line can be nipped by the conveying roller pair 71. Then, the leading edge of the preceding paper P1 is sent to the recording start position, and the first motor 91 and the fourth motor 94 are stopped. This is a so-called cueing operation.
Here, the recording start position refers to a position facing a nozzle row (not shown) of the recording head 82.

At this time, the difference between the one end side and the other end side in the width direction X of the paper P between the feed roller pair 96 and the transport roller pair 71 in the feed direction Y has not yet disappeared.
Here, the bending of the paper P between the feed roller pair 96 and the transport roller pair 71 acts so that the paper P is pushed downstream in the transport direction by the transport roller pair 71. Therefore, there is a possibility that a difference occurs between the transport amount on one end side in the width direction X and the transport amount on the other end side in the width direction X due to the difference in the amount of bending. As a result, there is a possibility that a so-called cumulative skew in which the paper P is newly inclined with respect to the feeding direction Y during conveyance after the skew removal is generated.
Therefore, in order to eliminate the difference between the deflection amount on the one end side and the deflection amount on the other end side, the following operation is executed.

FIG. 9 is a side view showing a normal rotation operation after skew removal according to the present invention.
As shown in FIG. 9, the control unit 90 first moves the second assist roller 51 in the direction away from the intermediate drive roller 50 by the second switching means 4 from the state of FIG. 8.
Here, the 2nd switching means 4 is comprised so that the 2nd assist roller 51 can switch between the 1st state which approached with respect to the intermediate drive roller 50, and the separated 2nd state. For example, it is possible to switch between the approaching first state and the separated second state by providing a cam as in the above-described swing mechanism 43.

  It should be noted that, of course, the intermediate drive roller 50 may be configured to move in a direction away from the second assist roller 51. This is also because in this case, the same effects as those described below can be obtained. In the present embodiment, the reason why the second assist roller 51 is configured to move is that the intermediate driving roller 50 is driven. That is, it is easier to move the second assist roller 51, which is the driven rotating side, than to move the intermediate driving roller 50, which is the driving side.

Next, the first motor 91 is driven in the normal direction to rotate the intermediate drive roller 50 in the clockwise direction in the drawing. During this time, the fourth motor 94 remains stopped.
At this time, the second assist roller 51 is separated from the intermediate drive roller 50. Therefore, the intermediate drive roller 50 can apply an appropriate feed force to the downstream side in the feed direction with respect to the paper P1 while sliding between the paper P1 and the outer periphery of the intermediate drive roller 50.

  Here, the “appropriate feeding force” is the degree to which the sheet P1 can be bent so as to be pressed outside the U-shaped feeding path between the feeding roller pair 96 and the conveying roller pair 71 in the feeding direction Y. Refers to the feed force. When the sheet P1 cannot be deflected further outward, a slip always occurs between the sheet P1 and the outer periphery of the intermediate drive roller 50, and so-called sheet jam occurs in which the sheet P1 is jammed in the feed path. There is no fear.

  As a result, it is possible to increase the amount of deflection of the paper P1 that has occurred between the feed roller pair 96 and the transport roller pair 71 in the feed direction Y. Here, between the feed roller pair 96 and the transport roller pair 71 in the feed path, a section R curved at least partially in side view is formed. Then, the sheet P1 can be pressed against the outside of the U-shaped feed path, that is, the curved outside of the section, so that the sheet P1 cannot be bent any more. That is, the sheet P1 can be made to have a predetermined amount of deflection by following the shapes of the U-shaped outer sheet guide unit 11 and the movable guide unit 6 in the second state.

Further, it is possible to eliminate the difference between the bending amount on the one end side of the paper P1 and the bending amount on the other end side. As a result, there is no possibility of a difference between the transport amount on the one end side and the transport amount on the other end side of the transport roller pair 71 at the time of subsequent recording.
Further, when the intermediate drive roller 50 is driven to rotate forward, the pickup roller 21 is in a state of moving away from the paper P as described above (see FIG. 5). Therefore, there is no possibility of preventing the difference between the deflection amount on the one end side of the paper P1 and the deflection amount on the other end side from being eliminated.

Furthermore, if the intermediate drive roller 50 is driven in reverse, the amount of bending of the paper P1 that has occurred between the feed roller pair 96 and the transport roller pair 71 in the feed direction Y can be reduced.
Then, similarly to the case where the intermediate drive roller 50 is driven to rotate forward, the difference between the deflection amount on the one end side of the paper P1 and the deflection amount on the other end side can be eliminated.

Here, the reason why the intermediate drive roller 50 is configured to rotate forward in this embodiment is that the sheet P1 moves away from the intermediate drive roller 50 when the intermediate drive roller 50 is driven forward. .
Assuming that the intermediate drive roller is driven in reverse, the sheet P1 behaves like being wound around the intermediate drive roller.
Therefore, in the present embodiment, it is possible to reduce the rotational load of the intermediate drive roller 50 as compared with the case where the intermediate drive roller is reversely driven.

  Thereafter, the first motor 91 and the fourth motor 94 are driven to rotate forward, and the intermediate drive roller 50 and the transport drive roller 72 are rotated in the clockwise direction in the drawing. At this time, the outer peripheral speed V1 of the intermediate driving roller 50 is desirably the same as the outer peripheral speed V2 of the transport driving roller 72. This is because it is not necessary to bend the sheet P1 further. As described above, the preceding sheet P1 is recorded by the recording unit 80 while being conveyed downstream in the feed direction by the conveying roller pair 71.

Further, the movable guide unit 6 is configured to maintain the second state until the rear end of the sheet P1 passes through the movable guide unit 6. Then, after the rear end of the sheet P1 passes through the movable guide unit 6, the first switching unit 5 switches the movable guide unit 6 from the second state to the first state. Specifically, the control unit 90 can determine whether or not the rear end of the sheet P1 has passed by the sheet detector 75 provided near the downstream side in the feed direction from the movable guide unit 6.
Of course, a sensor as a dedicated detection means for detecting the trailing edge of the paper P may be provided downstream of the movable guide portion 6 in the feeding direction.

  Then, after the rear end of the paper P1 passes through the paper detector 75, the movable guide 6 is switched to the first state. Thereby, there is no possibility that the switching operation from the second state to the first state of the movable guide unit 6 adversely affects the transport accuracy with which the transport roller pair 71 transports the paper P1. If the switching operation of the movable guide portion 6 from the second state to the first state is performed before the trailing edge of the sheet passes, the switching operation acts to push the sheet downstream in the sheet feeding direction. There is a risk that the conveyance accuracy will be reduced.

By preventing this, the conveyance accuracy can be stabilized. As a result, the recording accuracy can be stabilized. For example, there is no possibility that streaks in the width direction X due to unstable conveyance accuracy occur. So-called banding can be prevented.
Then, after recording is performed, the sheet is discharged to a discharge tray (not shown) in front of the printer 1 by a discharge unit (not shown).
In addition, during conveyance, a feed force may be generated by the transport roller pair 71 and the feed roller pair 96, or a feed force may be generated only by the transport roller pair 71.

  Further, when the paper P1 is cued, the intermediate driving roller 50 may be rotated in the clockwise direction in the drawing without stopping the forward driving of the transport driving roller 72. That is, after the skew is removed, the conveyance drive roller 72 is driven to rotate forward, and immediately after the leading edge of the paper P1 is nipped by the conveyance roller pair 71, the second assist roller 51 is moved away from the intermediate drive roller 50. Then, the intermediate drive roller 50 may be driven to rotate forward while slipping between the paper P1.

At this time, the outer peripheral speed V <b> 1 of the intermediate driving roller 50 is faster than the outer peripheral speed V <b> 2 of the transport driving roller 72. This is because when the transport roller pair 71 transports the paper P1, the difference between the left and right deflection amounts in the width direction on the rear end side of the paper P1 is substantially eliminated.
In such a case, the timing from when the feeding of the paper P1 is started to when the recording is started can be made earlier as compared with the case where the forward driving of the intermediate driving roller 50 is stopped. As a result, the throughput can be shortened.
The speed V1 of the intermediate drive roller 50 is preferably about 25 to 30% higher than the speed V2 of the transport drive roller 72. This is because the paper P1 can be bent appropriately.

Furthermore, in the present embodiment, the so-called “biting and discharging method” skew removal operation has been described, but the so-called “butting method” may be used.
Here, the “abutment method” is a transport roller in a state where the leading end of the paper P1 is stopped or reversely driven by the pair of feed rollers 96 as described above. This is a system in which the posture of the tip is made to follow the nip line by pressing against the nip line of the pair 71. That is, it refers to a system in which the leading edge of the sheet P1 is brought into contact with the conveying roller pair 71 so that the attitude of the leading edge follows the nip line. Of course, the sheet P1 is bent between the feeding roller pair 96 and the conveying roller pair 71 so that the posture of the leading edge follows the nip line.

FIG. 10 is a side view showing how the subsequent sheet is picked up in the present invention.
As shown in FIG. 10, after the preceding sheet P1 is conveyed to the recording unit 80, the sheet P can be continuously fed. Specifically, the control unit 90 detects the trailing edge of the paper P <b> 1 with the paper detector 75, and then moves the retard roller 41 and the second assist roller 51 closer to the intermediate drive roller 50. More specifically, the cam portion 45 is rotated by the second motor 92, and the retard holder (not shown) approaches the intermediate drive roller 50 by the urging force of the urging spring (not shown). Rock.

Similarly, the second switching means 4 is operated to move the second assist roller 51 in a direction approaching the intermediate drive roller 50.
Further, the control unit 90 drives the third motor 93 to swing the arm unit 22 around the arm shaft 23 in the direction in which the pickup roller 21 approaches the paper P placed on the cassette unit 14.

  At this time, the succeeding paper P2 held by the paper leading edge regulating ribs 60, 60 is displaced toward the intermediate drive roller by the approaching movement of the retard roller 41. Then, nipping is performed by the intermediate drive roller 50 and the retard roller 41. Therefore, the leading edge of the succeeding paper P2 is released from the restricted state by the paper leading edge regulating ribs 60, 60. In this state, as described above, the intermediate drive roller 50 and the pickup roller 21 are rotated clockwise in the drawing.

At this time, if there is one subsequent sheet P2 held by the sheet leading edge regulating ribs 60, 60, the one sheet P2 is fed downstream in the feeding direction.
If there are a plurality of subsequent sheets P2, P3,... Held by the sheet leading edge regulating ribs 60, 60, the relationship of friction coefficient μ4> friction coefficient μ2 and friction coefficient μ5> friction coefficient μ2 holds as described above. .

  Therefore, the feed force acting on the uppermost sheet P2 with respect to the intermediate drive roller 50 can be made larger than the feed force acting on the subsequent sheet P3. That is, the retard roller 41 separates the next and subsequent sheets P3, and only the uppermost sheet P2 can be sent downstream in the feed direction. At this time, the leading edge of the uppermost sheet P2 is displaced toward the intermediate driving roller side by the approaching movement of the retard roller 41 as described above, so there is no possibility of being regulated by the sheet leading edge regulating ribs 60 and 60.

  In the present embodiment, the feed path is U-shaped as viewed from the side, but is not limited thereto. It suffices to have at least a section R that is laterally curved. This is because it can be determined to which side the sheet P bends in the thickness direction Z of the sheet P. In addition, after the skew is removed, the difference in the amount of bending between the left and right in the width direction can be removed by driving the intermediate drive roller 50 in a state in which the second assist roller 51 is spaced forward.

Next, the first switching unit 5 will be described in more detail.
FIG. 11 is a schematic side view showing the structure of the first switching means of the present invention.
As shown in FIG. 11, the first switching unit 5 is configured to be able to transmit the power of the second motor 92 to the movable guide unit 6. Further, the first switching means 5 has a groove cam mechanism 8 as an example of a mechanism that can switch and displace the movable guide portion 6 between the first state and the second state. Of course, mechanisms other than the groove cam may be used.

  Specifically, the first switching means 5 includes the second motor 92, the pinion gear 32, the first compound gear 33, the third gear 34a and the fourth gear 34b constituting the planetary mechanism 34, and the fifth to ninth gears 35. ˜39 and the groove cam mechanism 8. Among these, the pinion gear 32 is provided in the second motor 92 and meshes with the first gear 33 a of the first compound gear 33. Further, the second gear 33b of the first compound gear 33 meshes with the third gear 34a.

  Furthermore, the fourth gear 34b is rotatably held by a planetary arm portion 34c that swings about the rotation fulcrum of the third gear 34a, and meshes with the third gear 34a. The fourth gear 34b swings in the same direction as the rotation direction of the third gear 34a, and can be engaged with the fifth gear 35 or a tenth gear 52 described later. The sixth gear 36 meshes with the fifth gear 35 and is formed integrally with a cam portion 45 that moves the retard roller 41 toward and away from the intermediate drive roller 50.

  Still further, the seventh gear 37 meshes with the sixth gear 36 so that power can be transmitted to the second switching means 4 that moves the second assist roller 51 toward and away from the intermediate drive roller 50. It is configured. Further, the eighth gear 38 meshes with the seventh gear 37 and the ninth gear 39. Furthermore, the groove cam mechanism 8 has a groove cam portion 9 and a protrusion 6 b that engages with the groove cam portion 9.

  Of these, the groove cam portion 9 is formed integrally with the ninth gear 39. On the other hand, the protrusion 6 b is provided on one end side with respect to a support shaft that is a swing fulcrum of the movable guide 6. Here, the other end side opposite to the one end side is the downstream side in the feeding direction of the movable guide portion 6 described above. Of course, the protrusion may be provided on the other end side. This is because it is sufficient that the movable guide portion 6 can be swung.

Moreover, the groove cam part 9 has the large diameter part 9a and the small diameter part 9b. And both sides of the small diameter portion 9b are smoothly connected to both sides of the large diameter portion 9a.
Therefore, when the pinion gear 32 rotates clockwise in FIG. 11, the fourth gear 34 b of the planetary mechanism 34 meshes with the fifth gear 35. Then, the groove cam portion 9 is rotated clockwise by the power of the second motor 92. At this time, the protrusion 6 b of the movable guide portion 6 is guided by the small diameter portion 9 b and the large diameter portion 9 a of the groove cam portion 9 and moves toward and away from the rotation fulcrum of the groove cam portion 9. Accordingly, the movable guide portion 6 can swing around the support shaft portion 7 as a fulcrum.

The support shaft portion 7 may be formed integrally with the movable guide portion 6 or may be formed integrally with the base portion 2. This is because the movable guide 6 can be swung in any case.
Moreover, in this embodiment, when the movable guide part 6 is switched between the first state and the second state, the movable guide part is swung. However, the present invention is not limited to this. The movable guide unit may be configured to move by sliding or the like. Further, the moving direction is not limited to the thickness direction Z and may be the feed direction Y. Even in such a case, it is possible to switch to the first state in which the space in the thickness direction of the paper in the feeding path is narrowed and the second state in which the space in the thickness direction is wider than the first state.

  The printer 1 includes a tenth gear 52, a second compound gear 53, a thirteenth gear 54, and a fourteenth gear 55. Among these, the 10th gear 52 is comprised so that it can mesh | engage with the 4th gear 34b which comprises the planetary mechanism 34. FIG. Further, the eleventh gear 53 a of the second compound gear 53 meshes with the tenth gear 52. Furthermore, the thirteenth gear 54 meshes with the twelfth gear 53 b of the second compound gear 53. The 14th gear 55 meshes with the 13th gear 54. Furthermore, the eccentric cam portion 56 is formed integrally with the thirteenth gear 54 and is configured to be able to transmit power to other mechanisms. For example, the recording head 82 may be moved toward and away from the medium support portion 81 to switch the interval between the recording head 82 and the paper P.

FIGS. 12A and 12B are schematic views showing the relationship between the movable guide portion and the groove cam mechanism. Among these, FIG. 12 (A) shows the said 1st state of a movable guide part. On the other hand, FIG. 12B shows the second state of the movable guide portion.
As shown in FIG. 12 (A), when the protrusion 6b of the movable guide portion 6 is located in the range of the large-diameter portion 9a of the groove cam portion 9, the downstream side 6a in the feed direction of the movable guide portion 6 is lowered. The first state is entered. At this time, as described above, the space between the downstream side 6a of the movable guide 6 in the feed direction and the inner paper guide 12 is closed.

  Here, a slight gap is provided between the projection 6b located in the range of the large diameter portion 9a and the side wall of the groove of the large diameter portion 9a. This is a so-called play gap. That is, the protrusion 6b located in the range of the large diameter portion 9a is provided so as to be slightly displaced in the radial direction with the rotation fulcrum of the groove cam portion 9 as a reference. Accordingly, the sheet P is pushed up to the leading end of the sheet P sent as described above and is slightly displaced in the clockwise direction in the drawing as indicated by a two-dot chain line.

  As a result, the downstream side 6a in the feed direction of the movable guide 6 and the inner paper guide 12 are slightly opened (see FIG. 3). The reason why the gap is slightly provided is to prevent the movable guide from being pushed up beyond a predetermined amount when the leading edge of the paper passes. Therefore, as described above, in the case of a configuration in which the front and back are not reversed and the reverse feed is not performed upstream in the feed direction during recording, it is not necessary to provide the play gap. In such a case, the state of the two-dot line shown in FIG. 12A may be the first state of the movable guide portion. Further, by forcibly maintaining the state of the two-point difference line, it is possible to minimize the path difference at the front end of the sheet in the left and right directions in the width direction.

  On the other hand, as shown in FIG. 12B, when the groove cam portion 9 is rotated in the clockwise direction in the drawing, the protrusion 6b of the movable guide portion 6 falls within the range of the small diameter portion 9b of the groove cam portion 9, It moves closer to the pivot point of the groove cam portion 9. Therefore, the movable guide portion 6 swings clockwise in the drawing with the support shaft portion 7 as a fulcrum. And the feed direction downstream side 6a of the movable guide part 6 can be switched to the second state, which is higher than the first state. At this time, as described above, the space between the downstream side 6a of the movable guide 6 in the feeding direction and the inner paper guide 12 is largely opened (see FIGS. 5 to 9). As a result, a sufficient bending space A can be ensured.

  A minimum gap is provided between the protrusion 6b located in the range of the small diameter portion 9b of the groove cam portion 9 and the side wall of the groove of the small diameter portion 9b, and the radial direction It is configured so that there is almost no play. This is to make the bending space A for bending the paper P constant. That is, it is for forcibly holding the second state of the movable guide portion 6. Also, if there is play, the weight of the movable guide portion 6 may act on the paper P being transported within the range of play, which may adversely affect the transport accuracy. That is, in the said 2nd state, conveyance accuracy can be stabilized by hold | maintaining the attitude | position of the movable guide part 6 firmly.

Further, when the groove cam portion 9 further rotates in the clockwise direction in the figure, the movable guide portion 6 can be switched from the second state to the first state.
In the present embodiment, the switching between the first state and the second state of the movable guide 6 is switched by the power of the second motor 92, but the present invention is not limited to this. Of course, other motors may be used, or a motor dedicated to the switching may be provided.

FIG. 13 shows the timing for switching the state of the movable guide portion according to the present invention.
As shown in FIG. 13, in step S <b> 1, the retard roller 41 is moved closer to the intermediate drive roller 50. Specifically, the control unit 90 drives the second motor 92 to move the retard roller 41 closer by the swing mechanism 43. Then, the process proceeds to step S2.

In step S2, feeding of the paper P is started (see FIGS. 1 to 3). Specifically, the control unit 90 drives the first motor 91 to feed the paper P to the downstream side in the feed direction by the pickup roller 21 and the feed roller pair 96. Then, the process proceeds to step S3.
In step S3, the leading edge of the paper P reaches the transport roller pair 71 (see FIG. 4). Specifically, the control unit 90 detects the leading edge of the paper P by the paper detector 75. Then, it is determined that the leading edge of the paper P has reached the transport roller pair 71 by feeding a predetermined amount from the time of detection. This is for determining the timing at which the retard roller 41 is moved away in step S4 to be described later. Then, the process proceeds to step S4.

In step S4, the retard roller 41 is moved away from the intermediate drive roller 50 (see FIG. 4). Specifically, the control unit 90 drives the second motor 92 and moves the retard roller 41 away by the swing mechanism 43. This is to reduce the back tension as described above. Then, the process proceeds to step S5.
In step S5, the movable guide 6 is switched from the first state to the second state (see FIGS. 5 and 6). Specifically, the control unit 90 drives the second motor 92 and switches the movable guide unit 6 to the second state by the first switching unit 5.

  This is to ensure a necessary and sufficient bending space A for performing skew removal when a skew removal operation is executed in step S6 described later. Here, it is desirable to maintain the first state of the movable guide unit 6 until the leading edge of the sheet P reaches the conveyance roller pair 71 and to switch the movable guide unit 6 to the second state immediately before bending the sheet P. . This is because the difference in the path of the leading edge of the paper P on the left and right in the width direction until the leading edge of the paper P reaches the conveyance roller pair 71 can be minimized. Then, the process proceeds to step S6.

In step S6, the skew removal operation is executed as described above (see FIGS. 6 to 8). Note that the skew removal method may be the above-described “biting and discharging method” or “butting method”. Then, the process proceeds to step S7.
In step S7, the second assist roller 51 is moved away from the intermediate drive roller 50 (see FIG. 9). Specifically, the control unit 90 drives the second motor 92 and moves the second assist roller 51 away by the second switching unit 4. This is to prevent accumulated skew and the like and stabilize the conveyance accuracy as described above. Then, the process proceeds to step S8.

In step S8, recording is performed on the paper P (see FIG. 9). In step S9, the paper P is discharged. Then, the process proceeds to step S10.
In step S10, the movable guide 6 is switched from the second state to the first state (see FIG. 10). Specifically, the control unit 90 drives the second motor 92 and switches the movable guide unit 6 to the first state by the first switching unit 5.

  This is because, as described above, since the rear end of the sheet P has already passed through the movable guide portion 6, even if the sheet P is switched to the first state, there is no possibility that the switching operation will adversely affect the sheet P1 that has passed. It is. Further, as described above, the leading edge of the succeeding paper P2 is sent to the transport roller pair 71 with high accuracy. That is, this is to stabilize the posture of the paper P2 in the previous stage of executing the skew removal operation. Then, the process proceeds to step S11.

  In step S11, the second assist roller 51 is moved closer to the intermediate drive roller 50 (see FIG. 10). Specifically, the control unit 90 drives the second motor 92 and moves the second assist roller 51 closer by the second switching means 4. This is for the purpose of providing the succeeding paper P2 so that it can be fed to the transport roller pair 71. Then, the sequence ends.

  The feeding unit 3 as the medium feeding device of the present embodiment includes a feeding roller pair 96 of the feeding unit 10 serving as a feeding unit that feeds the paper P, which is an example of a medium to be fed, to the downstream side in the feeding direction, and a feeding roller pair 96. A conveyance roller pair 71 that is arranged on the downstream side in the feed direction and transports the paper P sent by the feed roller pair 96 to the downstream side in the feed direction, and a section R that is curved in side view. A U-shaped outer sheet guide unit 11 and an inner sheet guide unit 12 as medium guide path units for guiding from 96 to the conveying roller pair 71, and a curved section R of the U-shaped outer sheet guide unit 11 and the inner sheet guide unit 12 A movable guide portion 6 that is provided on the outer side of the sheet P and can be switched between a first state in which the thickness direction Z of the paper P in the path space is narrowed and a second state in which the thickness direction Z is expanded from the first state; First switching means 5 for switching between the first state and the second state of the movement guide portion 6, and when the paper P is sent downstream in the feed direction by the feed roller pair 96, the paper P is downstream in the feed direction. The feeding unit 3 is configured to execute an operation of copying the posture of the leading end, which is an end, in a nip line direction that is a line formed by a circumscribed portion of the conveying roller pair 71. The movable guide section 6 is maintained until the first position of the movable guide section 6 is maintained until the position of the leading end of the sheet P is made to follow the nip line of the pair of transport rollers 71 until the movable guide section 6 passes. 6 is switched to the second state.

Further, in the present embodiment, after the movable guide portion 6 is switched to the second state, the second state is maintained until the rear end that is the upstream end in the feeding direction of the paper P passes through the movable guide portion 6. It is characterized by being.
Furthermore, in this embodiment, the feeding unit 10 is a feed roller pair 96 having an intermediate drive roller 50 as a feed drive roller that is driven by power and a second assist roller 51 as a feed driven roller that is driven to rotate. The conveyance roller pair 71 includes a conveyance drive roller 72 driven by power and a conveyance driven roller 73 that is driven to rotate, and the feed unit 3 includes the intermediate drive roller 50 and the second assist roller of the feed roller pair 96. And a second switching means 4 for switching the state of the intermediate drive roller 50 and the second assist roller 51 close to each other and the state of separation of the intermediate drive roller 50 and the second assist roller 51. After switching to the second state and causing the leading edge of the paper P to follow the nip line, the transport driving roller 72 is By driving, the feed roller pair 96 is switched to the separated state with the leading end of the paper P held between the transport roller pair 71, and the intermediate drive roller 50 is driven to rotate forward to drive the paper P to the U-shaped outer paper. The configuration is such that the guide unit 11 and the movable guide unit 6 in the second state are imitated.

  In the present embodiment, the conveyance driving roller 72 is driven to rotate forward so that the leading edge of the paper P is sandwiched between the conveyance roller pair 71, and then the conveyance driving roller 72 and the intermediate driving roller 50 are driven to rotate forward. It is the structure which sends to a feed direction downstream, Comprising: The speed of the outer periphery of the intermediate drive roller 50 in this case is a structure faster than the speed of the outer periphery of the conveyance drive roller 72, It is characterized by the above-mentioned.

The printer 1, which is an example of a recording apparatus according to the present embodiment, has a feeding unit 3 serving as a medium feeding unit that feeds a sheet P, which is an example of a recording medium, to the downstream side in the feeding direction, and a sheet P sent by the feeding unit 3. On the other hand, a recording unit 80 for recording by the recording head 82 is provided.
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

1 printer, 2 base section, 3 feeding section, 4 second switching means,
5 1st switching means, 6 movable guide part, 6a downstream of feed direction of movable guide part,
6b Projection part, 7 Support shaft part, 8 groove cam mechanism, 9 groove cam part, 9a Large diameter part,
9b Small diameter part, 10 feeding part, 11 U-shaped outer paper guide part, 12 inner paper guide part,
13 entanglement prevention part, 14 cassette part, 15 pad part, 20 pickup part,
21 pickup roller, 22 arm part, 23 arm shaft, 30 preliminary separation part,
31 bank separation unit, 32 pinion gear, 33 first compound gear, 33a first gear,
33b 2nd gear, 34 planetary mechanism, 34a 3rd gear, 34b 4th gear,
34c planetary arm, 35 fifth gear, 36 sixth gear, 37 seventh gear,
38 8th gear, 39 9th gear, 40 separation parts, 41 retard roller,
43 swing mechanism, 45 cam portion, 48 first assist roller,
50 intermediate drive roller, 51 second assist roller, 52 tenth gear,
53 2nd compound gear, 53a 11th gear, 53b 12th gear, 54 13th gear,
55 14th gear, 56 Eccentric cam part, 60 Paper leading edge regulating rib, 70 Conveying part,
71 transport roller pair, 72 transport drive roller, 73 transport driven roller,
74 driven roller holder, 75 paper detector, 76 sensor unit,
77 Paper detection lever, 80 recording unit, 81 medium support unit, 82 recording head,
90 control unit, 91 first motor, 92 second motor, 93 third motor,
94 4th motor, 96 feed roller pair, A deflection space, N nip point, P paper,
P1 preceding paper, P2 following paper, R curved section, X width direction,
Y feed direction, Z (paper) thickness direction

Claims (5)

Feeding means for feeding the medium to be sent downstream in the feeding direction;
A pair of transport rollers disposed downstream of the feed means in the feed direction and transporting the medium to be fed sent by the feed means downstream in the feed direction;
A medium guide path section that has a section curved in side view and guides a medium to be fed from the feeding means to the pair of conveying rollers;
A movable portion that is provided outside the curved section of the medium guiding path portion and can switch between a first state in which the thickness direction of the medium to be fed in the path space is narrowed and a second state in which the thickness direction is expanded from the first state. A guide,
First switching means for switching between the first state and the second state of the movable guide part,
When the medium to be fed is sent to the downstream side in the feeding direction by the feeding means, an operation is performed so that the posture of the tip which is the downstream end in the feeding direction of the medium to be fed follows the line direction formed by the circumscribed portion of the pair of conveying rollers A medium feeding device configured to
The medium feeding device maintains the first state of the movable guide unit until the tip of the medium to be fed passes through the movable guide unit.
A medium feeding device configured to switch the movable guide unit to the second state before executing an operation of causing the posture of the tip of the medium to be fed to follow the linear direction of the pair of conveying rollers.   2. The medium feeding device according to claim 1, wherein after the movable guide portion is switched to the second state, the second end until the rear end that is the upstream end in the feed direction of the medium to be fed passes through the movable guide portion. A medium feeding device that is configured to maintain the state. The medium feeding device according to claim 1 or 2, wherein the feeding means is a pair of feeding rollers having a feeding driving roller driven by power and a feeding driven roller that is driven to rotate.
The pair of transport rollers includes a transport drive roller that is driven by power, and a transport driven roller that is driven to rotate.
The medium feeding device relatively moves the feed driving roller and the feed driven roller of the feed roller pair in a state where the feed driving roller and the feed driven roller are close to each other and separated from each other. And further comprising a second switching means for switching between
The movable guide unit is switched to the second state, the posture of the tip of the medium to be fed is made to follow the linear direction, and then the conveyance driving roller is driven to rotate forward so that the tip of the medium to be fed is moved to the conveyance roller. The medium feed is configured to switch the pair of feed rollers to the separated state while being sandwiched between the pairs, and to drive the feed drive roller in a normal direction so that the medium to be fed follows the outside of the medium guide path portion. apparatus.   4. The medium feeding device according to claim 3, wherein the transport driving roller is driven to rotate forward so that the leading end of the medium to be fed is sandwiched between the transport roller pair, and then the transport driving roller and the feed driving roller are driven to rotate forward. The medium feeding device is configured to feed the medium to be fed to the downstream side in the feeding direction, and the outer peripheral speed of the feed driving roller at this time is faster than the outer peripheral speed of the transport driving roller. Medium feeding means for feeding a recording medium downstream in the feeding direction;
A recording unit for recording with a recording head on a recording medium sent by the medium feeding means,
5. The recording apparatus according to claim 1, wherein the medium feeding unit includes the medium feeding device according to claim 1, and the recording medium is the feeding medium.

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