JP2010046883A - Medium feeding device, recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transferring device having a conveying course which is formed to have a U-shaped side view and capable of stabilizing the conveyance amount. <P>SOLUTION: A medium feeding device (60) includes a pickup roller 16 which feeds a medium (P) to be fed to the downstream side in the feeding direction, a pair of carrying rollers 5 which convey the medium (P) thus fed, medium guide courses (61, 62) which are formed to have a U-shaped side view between the pickup roller 16 and the pair of carrying rollers 5 and guide the medium (P) to be fed up to the pair of carrying rollers 5, a medium detector (63) which detects the rear end of the medium (P) to be fed in the medium guide courses (61, 62), and a control means (65) which is configured to detect the rear end position of the medium (P) to be fed by means of the medium detector (63) and to correct the drive quantity of the pair of carrying rollers 5 from a correction value which is set according to the rear end position of the medium (P) to be fed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a pickup roller that picks up a placed medium to be fed and sends it to the downstream side in the feed direction, a pair of carry rollers that carries the sent medium to the downstream side in the feed direction, and from the pickup roller to the carry roller The present invention relates to a medium feeding device that includes a medium guide path section that forms a U-shaped portion between the pair of media and a guided medium to be fed to the pair of conveying rollers, and a recording device that includes the medium feeding 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 recording apparatus includes a conveyance device that conveys a sheet as an example of a medium to be fed. And it was comprised so that a paper could be conveyed by the conveyance roller pair to the recording part downstream in the conveyance direction. At this time, a so-called back tension, which is a conveyance load, is generated by the friction between the paper guide path and the paper. Therefore, the driving amount of the conveying motor that is the driving source of the conveying roller pair is corrected and controlled by the position of the trailing edge of the sheet.
JP 2007-63016 A

  However, the paper is transported from the rear to the front of the transport device, and is a so-called straight paper feed in which the transport path is substantially straight. The transport path is formed in a U-shape, and the paper is sent once from the front to the rear to be U-shaped It was not assumed to be a so-called front sheet feeding that is reversed and conveyed forward.

  The present invention has been made in view of such a situation, and a problem thereof is a transport apparatus capable of stabilizing a transport amount in a transport apparatus in which a transport path is formed in a U-shape when viewed from the side, and the transport apparatus. It is providing the recording apparatus provided with.

  In order to achieve the above object, a medium feeding device according to a first aspect of the present invention includes a pickup roller that picks up a placed medium to be fed and sends the medium to the downstream side in the feeding direction, and the sent medium to the downstream in the feeding direction. A conveying roller pair that conveys the sheet to the side, a medium guide path portion that forms a U-shape between the pickup roller and the conveying roller pair in a side view, and guides the medium to be fed to the conveying roller pair; In the path formed by the medium guide path section, a medium detector for detecting the trailing edge of the medium to be fed, and the position of the trailing edge of the medium to be fed are grasped by the medium detector, and the position of the trailing edge of the medium to be fed is determined. And a control unit configured to correct the driving amount of the conveying roller pair based on a correction value set accordingly.

  According to the first aspect of the present invention, the control means of the medium feeding device grasps the position of the trailing edge of the medium to be fed by the medium detector and sets it according to the position of the trailing edge of the medium to be fed. The driving amount of the conveying roller pair is corrected based on the corrected value. Here, the so-called back tension level, which is a load when feeding the medium to be fed, changes according to the position of the trailing edge of the medium to be fed. At this time, a correction value can be set according to the change in the level. As a result, the feeding accuracy of the medium to be fed can be stabilized with high accuracy.

Further, during the conveyance of the recording medium, the rear end of the medium to be fed which is bent along the shape of the U-shaped medium guiding path part comes into contact with the U-shaped outer part of the medium guiding path part. At this time, when the stiffness of the recording medium is relatively strong, the force to return the original shape of the recording medium acts as a so-called feeding force that is a force for moving the recording medium downstream in the transport direction. It is possible to deal with such cases and is effective.
Here, “the stiffness of the recording medium” refers to the elasticity of the recording medium. Of course, the correction value is changed depending on the strength of the recording medium.

According to a second aspect of the present invention, in the first aspect, the medium guide path portion is configured such that a rear end of the medium to be fed comes into contact with a U-shaped outer portion of the medium guide path portion, and the elasticity of the medium to be fed is increased. A propulsive force generation section that generates a force that is converted and travels downstream in the feed direction is provided, and the control unit is configured to use a correction value according to the propulsion force generation section.
According to the second aspect of the present invention, in addition to the same effects as the first aspect, the medium guide path portion includes the propulsive force generation section, and the control means responds to the propulsive force generation section. The correction value is used. In such a case, in the U-shaped medium guide path portion, the elasticity, which is a force for returning to the original shape of the medium to be fed, is converted into the feeding force, which is the advancing force, and thus is particularly effective. It is.

The recording apparatus according to the third aspect of the present invention includes a feeding unit that picks up a loaded recording medium and sends it to the downstream side in the feeding direction, and recording that performs recording on the conveyed recording medium by a recording head. A recording apparatus including the medium feeding device according to the first or second aspect.
According to a third aspect of the present invention, the feeding section includes the medium feeding device according to the first or second aspect. Therefore, in the recording apparatus, the same operational effects as those of the first or second aspect can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a printer as an image forming apparatus according to the present embodiment.
As shown in FIG. 1, the printer 1 is a thin printer in the Z-axis direction, which is the height direction. Further, the printer 1 has a rectangular box-shaped main body 112, and a carriage 40 extends in the central region of the main body 112 along the left-right direction X (main scanning direction (paper width direction)) in FIG. In this way, it is guided by the carriage guide shaft 41 installed in such a manner as to be reciprocally movable in the main scanning direction.

  As shown in FIG. 1, in the central region of the main body 112, a long plate-shaped paper guide front 39 is disposed at a lower position facing the carriage 40, with its longitudinal direction parallel to the main scanning direction X. ing. At the bottom of the front surface of the printer 1 (the front surface in FIG. 1), a paper cassette 11 for paper feeding can be inserted into and removed from a concave mounting portion 112A formed on the main body 112 so that the front surface is open. Attached (inserted). A plurality of ink cartridges 117 are loaded inside the cover 112 </ b> B that covers the front surface of the right end of the main body 112.

  The ink of each ink cartridge 117 is supplied to the carriage 40 through a plurality of ink supply tubes (not shown) attached to the flexible wiring board 118, and from a recording head 42 (shown in FIG. 2) provided at the lower portion of the carriage 40. Ink droplets are ejected (discharged). The recording head 42 includes a pressure element (piezoelectric element, electrostatic element, heating element, or the like) that applies pressure to the ink for ejecting the ink for each nozzle, and a predetermined voltage is applied to the pressure element. By being applied, ink droplets are ejected (discharged) from corresponding nozzles.

  At the time of printing, ink droplets are ejected from the recording head 42 in the process of moving in the main scanning direction together with the carriage 40 on the paper P that is fed from the paper cassette 11 and located on the paper guide front 39. One line is printed. In this way, printing on the paper P is advanced by alternately repeating the printing operation by one scanning of the carriage 40 and the paper transporting operation up to the next line. Also, various operation switches 120 including a power switch are provided at the lower left front surface of the main body 112.

  The overall configuration of the printer 1 will be outlined below with reference to FIG. The printer 1 includes a feeding device 2 at the bottom of the device, feeds recording sheets P one by one from the feeding device 2, performs ink jet recording in the recording means 4, and is on the front side of the device (left side in FIG. 2). A configuration is provided for discharging toward a paper discharge stacker (not shown).

  The feeding device 2 includes a paper cassette 11, a pickup roller 16, a guide roller 20, and a separating unit 21. The sheet cassette 11 that can store a plurality of sheets P in a stacked state is configured to be attachable to and detachable from the front side of the apparatus main body of the feeding apparatus 2, and is rotationally driven by a conveyance motor 64. The pickup roller 16 is provided on a swing member 17 that swings about a swing shaft 18, and rotates in contact with the paper stored in the paper cassette 11, thereby removing the uppermost paper P from the paper cassette 11. Send it out.

  A separating member 12 is provided at a position facing the leading edge of the paper stored in the paper cassette 11, and the leading edge of the uppermost paper P to be fed advances downstream while sliding on the separating member 12. First-stage separation from the next and subsequent sheets P is performed. A free-rotating guide roller 20 is provided on the downstream side of the separating member 12, and further, on the downstream side thereof, the separation roller 22 and the driving roller 23 are provided. Separation means 21 is provided.

  On the downstream side of the separating means 21, a driving roller 26 that is rotationally driven by a conveying motor 64 and an assist roller 27 that is driven to rotate while nipping the paper P between the driving roller 26 are configured. A first intermediate feeding unit 25 is provided, and the first intermediate feeding unit 25 feeds the paper P further downstream. Reference numeral 29 denotes a driven roller that reduces a paper passing load when the paper P passes through a U-shaped curved reversal path (particularly when the rear edge of the paper passes).

  On the downstream side of the driven roller 29, there is provided a drive roller 32 that is rotationally driven by a conveying motor 64, and an assist roller 33 that is driven to rotate while the paper P is nipped between the drive roller 32 and the drive roller 32. 2 intermediate feeding section 31 is provided, and the second intermediate feeding section 31 feeds the paper P further downstream.

  The recording unit 4 is disposed on the downstream side of the second intermediate feeding unit 31. The recording unit 4 includes a conveying unit 5, a recording head 42, a paper guide front 39, and a discharging unit 6. The transport means 5 includes a transport drive roller 35 that is rotationally driven by a transport motor 64, and a transport driven roller 36 that is pivotally supported on the paper guide 37 so as to be driven and rotated in pressure contact with the transport drive roller 35. The paper P is precisely fed toward the position facing the recording head 42 by the conveying means 5.

  The recording head 42 is provided at the bottom of the carriage 40. The carriage 40 is mainly guided by a CR (carriage) motor (not shown) while being guided by a carriage guide shaft 41 extending in the main scanning direction (front and back direction in FIG. 2). Driven to reciprocate in the scanning direction. A pre-paper guidance 39 is provided at a position facing the recording head 42, and the distance between the paper P and the recording head 42 is defined by the pre-paper guidance 39.

The discharge means 6 provided on the downstream side of the paper guide front 39 includes a discharge drive roller 44 that is rotationally driven by a conveyance motor 64 and a discharge driven roller 45 that is driven to rotate in contact with the discharge drive roller 44. The paper P configured and recorded by the recording means 4 is discharged by the discharge means 6 to a stacker (not shown) provided on the front side of the apparatus.
The feeding device 60 for feeding the paper P to the recording means 4 is composed of a feeding device 2 and a conveying means 5.

  Further, as described above, the paper P is picked up and then sent to the conveying means 5 through a U-shaped curved reversal path. Here, the curved reversal path having a U-shape when viewed from the side is constituted by a U-shaped outer guide section 61 outside the U-shape as a sheet guide path section and a U-shaped inner guide section 62 inside the U-shape.

Furthermore, an area on the upstream side in the conveyance direction from the first intermediate feeding unit 25 that is a roller pair of the driving roller 26 and the assist roller 27 in the conveyance path of the paper P is defined as an area A.
Further, when the strong paper P is bent due to the U-shaped curve on the downstream side in the transport direction from the area A, a force is generated to stretch the paper P, and the force to be stretched is transported. A region that is converted into a feed force that is a force pushed to the downstream side in the direction is a region B. Specifically, the region B is a region between the first intermediate feeding unit 25 and a position where the U-shaped curve ends.

  Furthermore, the sheet P is sent by the discharge means 6, the conveying means 5, and the second intermediate feeding portion 31, which is downstream in the conveying direction from the region B and the rear end of the paper P does not touch the U-shaped outer guide portion 61. Let the region be region C. Specifically, the region C is a region from the position where the U-shaped curve ends to the second intermediate feed unit 31. That is, this is an area where the second intermediate feeding section 31 affects the conveyance.

Further, an area in which the posture of the paper P is stabilized downstream of the area C and downstream of the second intermediate feeding unit 31 is defined as an area D.
Furthermore, it is downstream of the area D in the transport direction, the transport load due to the friction between the paper P and the transport path is reduced, the amount of winding of the paper P around the transport drive roller 35 is increased, and the transport amount of the paper P is increased. A region to be processed is a region E. Specifically, the area E is an area upstream of the transport unit 5 and the paper P on the upstream side of the transport unit 5 hardly comes into contact with a member of the transport path (reference numeral 37 or the like).

An area where the sheet P is sent only by the discharge unit 6 and downstream of the area E in the transport direction is an area F. Specifically, the region F is a region between the transport unit 5 and the discharge unit 6.
Furthermore, a non-contact type paper sensor 63 is provided between the separating unit 21 and the first intermediate feeding unit 25 in the transport direction. The paper sensor 63 is provided so that the presence or absence of the paper P can be detected.

  Here, when the paper sensor 63 detects the paper P and is in the ON state, it can be determined that the trailing edge of the paper P is located in the region A. Further, the driving amount of the driving roller 26 (first predetermined number of steps) required from the time when the rear end of the paper P passes through to the OFF state until the rear end of the paper P passes through the first intermediate feeding unit 25. ) Is set in advance. Accordingly, it can be determined that the trailing edge of the paper P has passed through the first intermediate feeding unit 25. That is, it is determined that the trailing edge of the paper P is located in the region A until the paper sensor 63 is switched between the ON state and the OFF state until the conveyance motor 64 is driven by the first predetermined number of steps. be able to.

  Further, a driving amount (second predetermined number of steps) of the driving roller 32 required from when it is determined that the trailing edge of the paper P has passed through the area A to when the trailing edge of the paper P has passed through the area B is set. Keep it. Accordingly, it can be determined that the trailing edge of the paper P is located in the region B. That is, after the paper sensor 63 is switched to the OFF state and the conveying motor 64 is driven for the first predetermined number of steps, the trailing edge of the paper P is a region from when the conveying motor 64 is driven for the second predetermined number of steps. It can be determined that it is located within B.

  Similarly, the driving amount (third predetermined number of steps) of the driving roller 32 required from when it is determined that the trailing edge of the paper P has passed the area B until the trailing edge of the paper P passes the area C is set. Keep it. Thereby, it can be determined that the trailing edge of the paper P is located in the area C. That is, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 is driven for the first predetermined number of steps and the second predetermined number of steps, until the conveyance motor 64 is driven for the third predetermined number of steps. It can be determined that the rear end of P is located in the region C.

  Further, the drive amount (fourth predetermined number of steps) of the transport driving roller 35 necessary from when it is determined that the trailing edge of the paper P has passed the area C until the trailing edge of the paper P passes the area D is set. Keep it. Accordingly, it can be determined that the trailing edge of the paper P is located in the region D. That is, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 drives the total amount of the first predetermined number of steps to the third predetermined number of steps, the conveyance motor 64 is driven for the fourth number of steps. Meanwhile, it can be determined that the trailing edge of the paper P is located in the region D.

  Furthermore, the driving amount (fifth predetermined number of steps) of the transport driving roller 35 required from when it is determined that the trailing edge of the paper P has passed through the region D to when the trailing edge of the paper P passes through the region E is set. Set it. As a result, it can be determined that the trailing edge of the paper P is located in the region E. That is, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 drives the total amount of the first predetermined number of steps to the fourth number of steps until the conveyance motor 64 is driven for the fifth number of steps. It can be determined that the trailing edge of the paper P is located in the region E.

  Further, a driving amount (sixth predetermined number of steps) of the discharge driving roller 44 required from when it is determined that the trailing edge of the paper P has passed through the region E to when the trailing edge of the paper P passes through the region F is set. Keep it. Thereby, it can be determined that the trailing edge of the paper P is located in the region F. That is, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 drives the total amount of the first predetermined number of steps to the fifth step, the conveyance motor 64 is driven for the sixth number of steps. It can be determined that the trailing edge of the paper P is located in the area F.

  Note that it is possible to determine which region the trailing edge of the paper P is in by setting the drive amount of one paper sensor 63 and the conveyance motor 64. However, the paper sensor 63 is located at the boundary of each region. May be provided. In such a case, the cost increases, but it is possible to more accurately determine which region the trailing edge of the paper P is in.

  FIG. 3 is a diagram showing the feed amount of each region when correction is not performed. The vertical axis represents the difference between the theoretical value of the “feed amount” of the paper P and the actual feed amount. 0 represents no difference from the theoretical value. The positive side represents sending more than the theoretical value. That is, the feed amount is excessive. On the other hand, the minus side represents sending less than the theoretical value. That is, the feed amount is insufficient. The horizontal axis represents the number of times of feeding (pass number) from the leading edge of the paper.

Here, “feed” means one paper feed in which the transport operation is disassembled in the transport state, so-called 1 Pass, and the paper feed amount per time is set in advance.
In addition, the “difference between the theoretical value and the actual feed amount” on the vertical axis of the graph is the difference between the feed amount accumulated by 18 Pass (from 1 to 18, from 2 to 19, from 3 to 20,...) And the theoretical feed amount. It is a difference, and the value 0 on the vertical axis means the theoretical feed amount. The reason why the feed amount is accumulated is that it is very difficult to confirm the difference because the difference from the theoretical value is very small. Therefore, the difference from the theoretical value is markedly shown by accumulation.

As shown in FIG. 3, when correction is not performed, when the paper P is picked up and sent downstream in the transport direction, the rear end of the paper P moves in the order of the areas A to B to F.
First, in the area A, the paper P is wound around the driving roller 26 and the like and is in a state of being bent by 90 degrees or more. Therefore, an unreasonable force acts on the paper feed, and the paper feed amount becomes a negative level from the theoretical value.
Next, in the region B, the rear end of the paper P comes into contact with the U-shaped outer guide portion 61 while the paper P is bent. At this time, when the stiffness of the paper P is strong, an elasticity is generated, which is a force for returning the posture of the paper P from the bent posture to the original straight posture. Then, the rear end of the paper P in contact with the U-shaped outer guide portion 61 acts so as to push out the entire paper P to the downstream side in the transport direction by the elasticity. As a result, the level of the feed amount in the area B becomes higher than that in the other areas.

Thereafter, in the region C, the rear end of the paper P is not in contact with the U-shaped outer guide 61. At this time, the paper P is fed by the three roller pairs of the second intermediate feeding unit 31, the conveying unit 5 and the discharging unit 6. Therefore, although it falls below the level of area B, it can be sent relatively stably.
Thereafter, the trailing edge of the paper P passes through the second intermediate feeding portion 31 and enters the region D. At this time, the paper P is sent by the transport unit 5 and the discharge unit 6. The posture of the paper P is a stable state that is hardly curved, and the feed amount is relatively stable.

Thereafter, the trailing edge of the paper P enters the region E. At this time, since the number of contact points between the paper P and the transport path member is reduced, the frictional resistance between the paper P and the transport path member is reduced. At the same time, the amount of wrapping of the paper P around the transport driving roller 35 which is the transport means 5 increases, so that the feed amount increases.
After that, the rear end of the paper P passes through the conveying means 5 and enters the region F. At this time, the paper P is sent by the transport means 5. Since there is almost no contact between the paper P and the members of the transport path, the level of the feed amount is high compared to other areas.

As described above, when the correction is not performed, the level of the feed amount varies for each region. Therefore, different correction is performed for each region. Hereinafter, how to determine the correction value and the content of the correction value will be described.
Since the level of the feed amount varies depending on the position of the trailing edge of the paper, the same tendency as the variation shown in FIG. 3 is obtained even when the paper sizes are different.

FIG. 4 is a sequence diagram for determining a correction value for the driving amount of the conveyance motor according to the invention.
As shown in FIG. 4, in step S <b> 11, it is determined whether or not the trailing edge of the paper P is in the area A. Specifically, as described above, when the paper sensor 63 is in the ON state and when the number of steps of the transport motor 64 after switching to the OFF state is less than the first predetermined number of steps, the trailing edge of the paper P Can be determined to be within region A. When it is determined that the trailing edge of the paper P is in the area A, the control unit 65 (see FIG. 2) adds the correction value A and drives the transport motor 64.

Here, as described above, the conveyance drive roller 35 and the drive rollers 32, 23, and 26 are driven by the power of the conveyance motor 64. The “correction value A” is a correction value that sets the level of the feed amount in the region A in FIG. 3 to a level where the difference from the theoretical value is zero.
Therefore, when the trailing edge of the paper P is in the area A, a desired feed amount can be obtained.
On the other hand, if it is determined that the trailing edge of the paper P is not in the area A, the process proceeds to step S12.

  In step S12, it is determined whether or not the trailing edge of the paper P is within the area B. Specifically, as described above, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 is driven for the first predetermined number of steps, the conveyance motor 64 is driven for the second predetermined number of steps. If so, it can be determined that the trailing edge of the paper P is located in the region B. When determining that the trailing edge of the paper P is within the region B, the control unit 65 adds the correction value B and drives the transport motor 64.

Here, the “correction value B” is a correction value that sets the level of the feed amount in the region B in FIG. 3 to a level where the difference from the theoretical value is zero. As described above, in the region B, a force acts to push the entire sheet P to the downstream side in the transport direction due to the bending of the sheet P at the position where the rear end of the sheet P and the U-shaped outer guide portion 61 are in contact with each other. Needless to say, when the force at this time is very strong and the feed amount becomes larger than the theoretical value, the drive amount of the transport motor 64 is corrected. That is, the correction value B is changed in accordance with the type of paper P and the strength of stiffness.
Therefore, when the trailing edge of the paper P is in the area B, a desired feed amount can be obtained.
On the other hand, if it is determined that the trailing edge of the paper P is not in the area B, the process proceeds to step S13.

  In step S13, it is determined whether or not the trailing edge of the paper P is within the area C. Specifically, as described above, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 is driven by the first predetermined step number and the second predetermined step number, the conveyance motor 64 is changed to the third predetermined step. It is possible to determine that the trailing edge of the paper P is located in the region C until the number of driving is completed. If it is determined that the trailing edge of the paper P is within the region C, the control unit 65 adds the correction value C and drives the transport motor 64.

Here, the “correction value C” is a correction value that sets the level of the feed amount in the region C in FIG. 3 to a level where the difference from the theoretical value is zero.
Accordingly, when the trailing edge of the paper P is in the area C, a desired feed amount can be obtained.
On the other hand, if it is determined that the trailing edge of the paper P is not in the area C, the process proceeds to step S14.

  In step S14, it is determined whether or not the trailing edge of the paper P is within the region D. Specifically, as described above, after the paper sensor 63 is switched to the OFF state and the conveying motor 64 drives the total amount of the first predetermined step number to the third predetermined step number, the conveying motor 64 is activated. It can be determined that the trailing edge of the paper P is located in the region D until the fourth step number drive. When determining that the trailing edge of the paper P is within the region D, the control unit 65 adds the correction value D and drives the transport motor 64.

Here, the “correction value D” is a correction value that sets the level of the feed amount in the region D in FIG. 3 to a level where the difference from the theoretical value is zero.
Accordingly, when the trailing edge of the paper P is in the area D, a desired feed amount can be obtained.
On the other hand, if it is determined that the trailing edge of the paper P is not in the area D, the process proceeds to step S15.

  In step S15, it is determined whether or not the trailing edge of the paper P is within the area E. Specifically, as described above, after the paper sensor 63 is switched to the OFF state and the conveyance motor 64 drives the total amount of the first predetermined step number to the fourth step number, the conveyance motor 64 is changed to the first one. It can be determined that the trailing edge of the paper P is located in the area E until the number of steps is driven. If it is determined that the trailing edge of the paper P is in the area E, the control unit 65 adds the correction value E and drives the transport motor 64.

Here, the “correction value E” is a correction value that sets the level of the feed amount in the region E in FIG. 3 to a level where the difference from the theoretical value is zero.
Therefore, when the trailing edge of the paper P is in the area E, a desired feed amount can be obtained.
On the other hand, when determining that the trailing edge of the paper P is not within the region E, the control unit 65 adds the correction value F and drives the transport motor 64.

Here, the “correction value F” is a correction value that sets the level of the feed amount in the region F in FIG. 3 to a level where the difference from the theoretical value is zero.
Therefore, when the trailing edge of the paper P is in the area F, a desired feed amount can be obtained.
When the trailing edge of the paper P passes through the area F, the transport motor 64 is stopped, or the transport motor 64 is driven by adding the correction value A to transport the next paper. is there.

As described above, the driving amount of the conveyance motor 64 is corrected according to each region. Therefore, a desired feed amount can be obtained in each region. As a result, the feed amount can be kept constant as a whole, and the recording accuracy can be improved.
In this embodiment, the area is divided into six areas A to F, but it is needless to say that the area may be divided more finely. In such a case, the level of the feed amount can be stabilized more accurately.
Of course, the correction values A to F can be changed according to the stiffness of the paper.
Furthermore, as described above, the level of the feed amount varies depending on the position of the trailing edge of the paper P. Also, when the paper sizes are different, there is a tendency similar to the variation shown in FIG. 3, and similarly, the desired feed amount can be obtained by driving the transport motor 64 with the correction values A to F added thereto. .

  A feeding device 60 as a medium feeding device of the present embodiment picks up a sheet P that is an example of a medium to be fed and picks up the sheet P that feeds the downstream side in the feeding direction, and the feeding sheet P downstream in the feeding direction. As a medium guide path section that forms a U-shape between the conveying means 5 as a pair of conveying rollers that convey to the side and the pickup roller 16 to the conveying means 5 and guides the paper P to be conveyed to the conveying means 5 Paper sensor as a medium detector for detecting the trailing edge of the paper P in the path formed by the U-shaped outer guide part 61 and the U-shaped inner guide part 62 and the U-shaped outer guide part 61 and the U-shaped inner guide part 62 63 and a control unit that grasps the position of the trailing edge of the sheet P by the sheet sensor 63 and corrects the driving amount of the conveying unit 5 based on a correction value set according to the position of the trailing edge of the sheet P. When The control unit 65 of Te, characterized in that it comprises.

Further, in this embodiment, the U-shaped outer guide portion 61 and the U-shaped inner guide portion 62 abut the U-shaped outer guide portion 61 of the U-shaped rear end of the paper P, convert the elasticity of the paper P, and change the paper P The control unit 65 is configured to use a correction value corresponding to the region B, and the control unit 65 includes a region B as a propulsive force generation section that generates a force traveling downstream in the feed direction.
The ink jet printer 1 that is a recording apparatus of the present embodiment includes a feeding device 60 as a feeding unit that picks up a sheet P that is an example of a recording medium that is placed and feeds the sheet P downstream in the feeding direction, and the conveyed sheet P On the other hand, the recording head 4 includes a recording unit 4 as a recording unit that performs recording by the recording head 42.

  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 is a perspective view showing an entire printer according to the present invention. FIG. 3 is a side cross-sectional view illustrating a paper conveyance path of the printer according to the embodiment of the invention. The figure which shows the feed amount for every area | region when not correct | amending. The sequence diagram which determines the correction value of the drive amount of the conveyance motor which concerns on this invention.

Explanation of symbols

1 ink jet printer, 2 feeding device, 4 recording means, 5 conveying means,
6 discharging means, 11 paper cassette, 12 separating member, 16 pickup roller,
17 oscillating member, 18 oscillating shaft, 20 guide roller, 21 separating means,
22 Separating roller, 23 Driving roller, 25 First intermediate feeding section, 26 Driving roller,
27 assist roller, 29 driven roller, 31 second intermediate feed section, 32 drive roller,
33 Assist roller, 35 Conveyance drive roller, 36 Conveyance driven roller,
37 on paper guide, 39 before paper guide, 40 carriage, 41 carriage guide shaft,
42 recording head, 44 discharge driving roller, 45 discharge driven roller, 60 feeding device,
61 U-shaped outer guide, 62 U-shaped inner guide, 63 Paper sensor,
64 conveying motor, 65 control unit, 112 main body, 112A mounted portion,
112B cover, 117 ink cartridge, 118 flexible wiring board,
120 Operation switch, P paper, X width direction, Y feed direction during recording, Z height direction

Claims (3)

A pickup roller for picking up the medium to be sent and feeding it downstream in the feed direction;
A pair of transport rollers for transporting the fed medium to the downstream in the feed direction;
A medium guide path that forms a U-shape between the pickup roller and the pair of transport rollers in a side view, and guides a medium to be fed to the pair of transport rollers,
A medium detector for detecting a rear end of the medium to be fed in a path formed by the medium guide path;
Control in which the position of the trailing edge of the medium to be fed is grasped by the medium detector, and the driving amount of the conveying roller pair is corrected based on a correction value set according to the position of the trailing edge of the medium to be fed. And a medium feeding device. The medium feeding device according to claim 1, wherein the medium guide path portion includes a rear end of the medium to be contacted with a U-shaped outer portion of the medium guide path portion, and converts the elasticity of the medium to be fed to be fed. Providing a propulsive force generation section that generates a force to the medium to travel downstream in the feed direction,
The medium feeding device having a configuration in which the control means uses a correction value corresponding to the propulsive force generation section. A feeding section that picks up the recording medium placed and sends it to the downstream side in the feeding direction;
A recording unit that performs recording on a conveyed recording medium by a recording head,
The recording apparatus including the medium feeding device according to claim 1 or 2, wherein the feeding unit includes the medium feeding device.

Images