JP2006117384A - Medium feeding device, and recording apparatus and liquid ejecting apparatus provided with the medium feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the setting property of a medium, prevent the front end of the medium from being scratched or broken, and prevent a double feed even when a small number of sheets are stored in a paper storage unit, thereby achieving good feeding. It is an object of the present invention to provide a medium feeding device that can realize the above.
A sheet feeding device according to the present invention has a feeding downstream pad surface 423a of a friction pad 423 formed in parallel with a bottom 421 (medium storage surface) of a bank separating unit 42, and a feeding upstream pad. The surface 423b is formed in a shape recessed from the bottom 421. As a result, the setability for storing the paper in the medium storage means is improved, correct paper storage is facilitated, and it is possible to prevent the front end of the paper from being scratched or broken. Further, since the feeding downstream side pad surface 423a is formed in parallel with the bottom portion 421, an increase in the biting load S2 is suppressed, and even when a small number of sheets are stored in the sheet storing section, double feeding is prevented. Is possible.
[Selection] Figure 7

Description

  The present invention relates to a medium feeding device that feeds a medium, and a recording apparatus and a liquid ejecting apparatus including the medium feeding device.

  Inkjet printers, which are one type of recording apparatus, include a type that feeds paper from the back side and discharges it to the front side, and a type that feeds and discharges paper on the front side. A printer that feeds and discharges paper on the front side has, for example, a paper feed tray disposed in the lower part of the front surface of the apparatus and a paper discharge stacker disposed in the upper part. Then, the paper stored in the paper feed tray is started to be fed by a pickup roller (medium feeding means). At this time, the double-fed paper is separated into the uppermost paper and the lower paper by the separating means, and only the uppermost paper is fed by a paper feed roller or the like. The paper fed by a paper feed roller or the like is fed to a recording unit and recorded, and then discharged onto a paper discharge stacker by a paper discharge roller or the like. As an example of the separating means described above, a pick-up roller that can separate and feed only one sheet in contact with the stacked sheets, a pressure plate in which a separation pad is embedded in a portion where the pick-up roller is pressed, For example, Japanese Patent Application Laid-Open No. H10-228473 discloses a paper separation mechanism for a printer having a printer.

JP 2000-159368 A

  In the paper separation mechanism described in the above-mentioned Patent Document 1, a pickup roller that can separate and convey only one sheet in contact with the stacked sheets, and a separation pad are embedded in a portion where the pickup roller is in pressure contact. And a pressure separating plate, wherein the length of each separation pad in the direction perpendicular to the sheet feeding direction is shorter than the length of each corresponding pickup roller. Thus, it is possible to adjust the frictional force between the pickup roller and the paper and the paper and the separation pad at the time of paper separation, and the paper separation and feeding can be performed stably.

  In the paper separating mechanism described in Patent Document 1, as shown in FIG. 1 of Patent Document 1, since the separation pad is disposed so as to protrude from the upper surface of the pressure plate, the paper setting property is poor. That is, when the paper is set in the storage unit, the front end of the paper collides with the side surface of the separation pad, which may cause an obstacle during storage of the paper and may cause scratches or breakage of the paper.

  Further, an aspect in which the separation pad is inclined (see FIG. 9) in order to improve the sheet setting property is employed in a sheet storage portion of a type that feeds paper from the back side. However, in the aspect in which the separation pad is inclined, the sheet setting property is improved, but the biting load generated by the rotation of the pickup roller is increased, and multifeed is caused particularly when a small number of sheets are stored in the sheet storage unit. There is a fear.

  The present invention has been made in view of the various problems as described above. The object of the present invention is to improve the setting property of the medium, prevent the front end of the medium from being scratched or broken, and a small number of sheets. To provide a medium feeding device capable of preventing double feeding even when stored in a paper storage unit and realizing good feeding, and a recording apparatus and a liquid ejecting apparatus including the feeding device. is there.

  To achieve the above object, the medium feeding device of the present invention includes a medium storing means for storing a medium and a medium feeding means for feeding the medium, and is sandwiched by the medium feeding means to form the medium. Is a medium feeding device in which a pad for feeding is disposed in the medium storage means, and a pad surface on the downstream side of the pad is formed in parallel with the medium storage surface of the medium storage means, The feeding upstream pad surface is formed in a shape recessed from the medium storage surface.

  Thereby, since the pad surface on the upstream side of the pad is formed in a shape retracted from the medium storage surface, the setability for storing the medium in the medium storage means is improved, and correct medium storage is facilitated. It becomes possible to prevent the front end of the medium from being scratched or broken. Further, since the pad surface on the downstream side of the feeding of the pad is formed in parallel with the medium storage surface of the medium storage means, even if a small number of sheets are stored in the sheet storage unit, an increase in biting load is suppressed. It becomes possible to prevent double feeding.

  In the medium feeding device of the present invention, the feeding upstream pad surface is a surface including a slope or a circumferential surface. As a result, the medium can be smoothly stored in the medium storing means, and the setting property of the medium can be improved.

  In the medium feeding device of the present invention, the feeding upstream side of the pad is embedded in the medium storing means. As a result, it is possible to effectively use the space.

  In the medium feeding device according to the present invention, the medium feeding means is in contact with the feeding downstream pad surface. As a result, the medium is sandwiched between the medium feeding means and the pad surface on the downstream side of feeding, so that the medium can be reliably fed / separated and the feeding performance of the medium can be improved. Is possible.

  In order to achieve the above object, the recording apparatus of the present invention is a recording apparatus for recording on a medium, and is provided with each of the medium feeding apparatuses. In order to achieve the above object, the liquid ejecting apparatus of the present invention is a liquid ejecting apparatus that ejects a liquid onto a medium to be ejected, and includes the above-described medium feeding devices. Thereby, a recording apparatus or a liquid ejecting apparatus that exhibits the above-described effects can be provided.

  Hereinafter, as an embodiment of a medium feeding apparatus according to the present invention, a medium feeding apparatus used in an ink jet printer that is one of recording apparatuses will be described with reference to FIGS. 1 to 11. The embodiments described below do not limit the invention according to the claims, and all the combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent.

  FIG. 1 is a perspective view showing the entire external configuration of an ink jet type multifunction peripheral 100 that is one of recording apparatuses according to an embodiment of the present invention, FIG. 2 is a perspective view showing the internal structure thereof, and FIG. 3 is a schematic view thereof. It is a side view. The ink jet type multifunction peripheral 100 has a printer function capable of recording on, for example, a JIS standard L size, A6 size to A4 size cut sheet or postcard, a JIS standard size A4 size original, A scanner function that can read originals up to US standard letter size and a copy function that can copy on JIS standard L size, 2L size, B5 size, A4 size, six-cut, postcard size paper I have.

  As shown in FIG. 1, the inkjet multifunction peripheral 100 is entirely covered with a substantially rectangular parallelepiped housing 101, a printer 110 is disposed in the lower stage, and a scanner 120 is disposed in the upper stage. ing. A sheet feeding / discharging unit 140 including a sheet feeding device 142 (see FIG. 3) as a medium feeding device according to the present invention is disposed on the front side, and a sheet feeding unit 130 is disposed on the back side. . Since the user can select one or both of the paper feeding unit 130 on the rear side and the paper feeding / discharging unit 140 on the front side as the setting direction of the paper before recording, the degree of freedom of the installation position of the inkjet multifunction peripheral 100 Can be increased. Furthermore, since the paper after recording is always discharged from the paper supply / discharge unit 140 on the front side, the user can easily take out the paper.

  A rectangular flat plate-shaped scanner cover 102 shown in FIG. 1 is disposed on the upper surface of the housing 101. The scanner cover 102 has a handle 103 formed at the front, and is attached so as to be rotatable in the direction of the arrow A in the figure around a rear rotation shaft. When using the scanner 120, the user can open and close the scanner cover 102 by inserting a finger into the handle 103, so that the user can easily put in and out the document.

  On both sides of the front surface of the housing 101, cartridge housing portions 104, 104 are formed in which a plurality of ink cartridges 109 shown in FIG. Each ink cartridge 109 stores ink of each color for recording. Each cartridge storage section 104 is covered with a transparent or translucent cartridge cover 105 shown in FIG. The cartridge cover 105 is attached so as to be rotatable in the direction of the arrow B shown in the figure with a rotation shaft at the lower part thereof as a center. Even if the user does not lift the entire heavy scanner 120 and open the inside of the printer 110 as in the prior art, the ink cartridge can be released by simply pressing the cartridge cover 105 to release the locking portion and opening the cartridge storage portion 104. 109 replacement work or the like can be performed, so that work efficiency can be improved.

  As shown in FIG. 1, an operation unit 106 for instructing each operation of the printer 110, the scanner 120, and the copy is disposed in front of the scanner cover 102 on the upper surface of the housing 101. The operation unit 106 includes a power system for turning on / off the power, an operation system for operating the cueing of paper, operating an ink flushing, a processing system for performing image processing, etc. A liquid crystal panel 107 and the like for displaying are provided. The user can operate buttons and the like while looking at the liquid crystal panel 107 for confirmation.

  In the housing 101, as shown in FIGS. 2 and 3, a paper supply / discharge unit 140, a paper supply unit 130, a recording unit 150, and the like including a paper feeding device 142 according to the present invention are disposed. As shown in FIG. 1, the paper feed unit 130 is formed with a rear paper feed port 31 that is open upward in a rectangular shape, and frames 32 are formed along both edges and the rear edge of the rear paper feed port 31. It is arranged. As shown in FIGS. 1 to 3, the frame 32 automatically has a paper support 33 that supports one or more sheets to be fed and a sheet supported by the paper support 33 one by one. A rear sheet feeding mechanism (hereinafter referred to as “rear ASF”) 34 and the like for feeding to the sheet are disposed.

  FIG. 4 is a side view showing details of the paper support 33 and the rear ASF 34. The sheet feeding unit 130 will be described with reference to FIGS. The paper support 33 is substantially constituted by a first support 33a and a second support 33b that support the back surface of the paper, and is connected to a pair of edge guides (a movable edge guide 35a and a fixed edge guide 35b) that regulate the width of the paper from both sides. It is installed.

  The first support 33a is formed in a flat plate shape and is disposed inside the rear wall of the frame 32 so as to be retractable and retractable. The second support 33b is formed in a flat plate shape and can be stored and pulled out in the first support 33a. It is arranged. Since the first support 33a and the second support 33b are formed to be extendable in the paper feeding direction, they can be stored compactly when not in use, and various sizes of paper can be stored when in use. Can support reliably.

  The fixed edge guide 35b is formed in a shape along the right side wall as viewed from the apparatus front side of the frame 32, and the movable edge guide 35a is formed in a shape along the left side wall as viewed from the apparatus front side of the frame 32. It is attached so that it can move between the left side wall and the right side wall substantially parallel to the rear wall of the frame 32 (see FIG. 2). Since the movable edge guide 35a and the fixed edge guide 35b can reliably guide both side edges of the paper even if the paper sizes are different, the paper can be reliably fed.

  Next, the rear ASF 34 shown in FIG. 4 includes a hopper 36 for lifting the paper supported by the paper support 33, a paper feed roller 37 for taking out the paper lifted by the hopper 36, and the paper feed roller 37. A rear retard roller 38 that separates the sheets fed in double by the rear retard roller 38, a rear paper return unit 39 (see FIG. 4) for returning the remaining sheets separated by the rear retard roller 38 to the hopper 36, and the like. .

  The hopper 36 is formed in a flat plate shape on which a sheet can be placed, and is disposed substantially parallel to the rear wall of the frame 32, the lower end is positioned near the paper feed roller 37, and the upper end is the rear wall of the frame 32. It arrange | positions so that it may be located close to the top part (refer FIG. 2, FIG. 4). The hopper 36 has the other end of a compression spring (not shown) having one end attached to the rear wall of the frame 32 on the back surface on the lower end side, and the lower end side pivots about the upper end side by expansion and contraction of the compression spring. It is arranged like this.

  The paper feed roller 37 is formed in a D-shape with a part cut away, and is disposed in the vicinity of the lower end of the hopper 36. The paper feed roller 37 rotates intermittently and frictionally feeds the paper lifted by the hopper 36. (See FIG. 4). The rear retard roller 38 is disposed so as to be in contact with the paper feed roller 37, and when the paper is fed by the paper feed roller 37, only the uppermost paper is frictionally separated from the lower paper. ing. The rear paper return unit 39 is formed in the shape of a claw and is disposed in the vicinity of the paper feed roller 37. The lower paper separated by the rear retard roller 38 is hooked on the claw and returned to the hopper 36. (See FIG. 4).

  Next, with reference to FIG. 2 and FIG. 3, the paper feed / discharge unit 140 including the paper feeding device 142 according to the present invention will be described. As shown in FIGS. 2 and 3, the paper supply / discharge unit 140 is formed with a front paper supply / discharge port 141 that opens in a rectangular shape toward the front, and the present invention is located on the back side of the front paper supply / discharge port 141. The paper feeding device 142 according to the above is disposed. As shown in FIG. 3, the sheet feeding device 142 automatically feeds the sheets stored in the sheet feeding tray 40 one by one, the sheet feeding tray 40 mainly constituting a medium storing unit for storing a medium (paper). A front paper feed mechanism (hereinafter referred to as “front ASF”) 144 that feeds the paper to a paper feed tray, and a front paper discharge mechanism (hereinafter referred to as “front ASF”) that automatically discharges paper to a paper discharge tray 143 disposed above the paper feed tray 40. 145) (referred to as “front EJ”).

  As shown in FIGS. 2 and 3, the sheet feed tray 40 is formed in a flat plate shape, and the sheets to be fed before recording are stacked and stored substantially horizontally on the upper surface. As shown in FIGS. 2 and 3, the paper discharge tray 143 includes a first tray 143a, a second tray 143b, and a third tray 143c. The first tray 143a is formed in a flat plate shape, and the rear part is rotatably disposed on the main body frame 108 of the paper feed / discharge unit 140, and the second tray 143b is formed in a flat plate shape and the first tray 143a. The third tray 143c is formed in a flat plate shape so as to be retractable and retractable on the second tray 143b.

  The sheet discharge tray 143 shown in FIG. 3 is configured such that sheets to be discharged after recording are stacked on the upper surface in a state where the second tray 143b and the third tray 143c are pulled out. Since the second tray 143b and the third tray 143c are formed to be extendable in the paper discharge direction, they can be stored compactly when not in use, and various sizes of paper can be discharged when in use. The stacked sheets can be surely stacked and placed. The paper supply / discharge unit 140 is also configured to be able to manually feed and discharge a medium such as thick paper or an optical disk that cannot be bent during paper supply / discharge.

  FIG. 5 is a side view showing details of the front ASF 144. The front ASF 144 will be described with reference to FIGS. 3 and 5. The front ASF 144 has a pickup roller unit 41 (medium feeding means) that pushes out the paper stored in the paper feed tray 40 and a paper that has been multi-fed by bringing the leading edge of the paper pushed out by the pickup roller unit 41 into contact with each other. And a bank separation part 42 (first separation means) for separating the two. Further, the front ASF 144 according to the present embodiment reverses the fed paper into a U-shape, a retard separation unit 43 as a second separation unit that separates the multi-layer paper that could not be separated by the bank separation unit 42. An intermediate roller 45 and an assist roller 46 are provided. Here, the bank separation part 42 including the characteristic part of the present invention will be described with reference to FIG.

  FIG. 6 is a perspective view showing a bank separating section 42 as a first separating means. As shown in FIG. 6, the bank separation unit 42 includes a bottom part 421 that is connected to the paper feed tray 40, and a bank slope part 420 that is formed so as to incline toward the rear at the back end of the bottom part 421. , In general. The bottom portion 421 is integrated with the paper feed tray 40 and stacks the paper stored above it. In the present embodiment, the paper feed tray 40 and the bank separation unit 42 are integrated to function as medium (paper) storage means. On the bottom 421, a friction pad 423 forming a characteristic portion of the present invention is disposed near the center in the width direction (direction perpendicular to the feeding direction X). The friction pad 423 can contact the pickup roller unit 41, and the sheet sandwiched between the pickup roller unit 41 and the friction pad 423 is fed in the feeding direction X. The friction pad 423 is formed of a member having a high friction coefficient. For example, a cork material is used in the present embodiment. A plurality of ribs 422 are formed on the bank inclined portion 420, and the top surfaces of the ribs 422 are stacked and stored on the paper feed tray 40 and the bottom portion 421 (hereinafter referred to as “paper feed tray 40”). Abut. The inclination angle of the bank inclined portion 420, the surface state of the rib top surface, and the like have a great influence on the separation of the paper, and are set to a suitable state in consideration of the paper (medium) to be fed.

  Next, it returns to description about the front ASF 144 (see FIG. 3 and FIG. 5). The pickup roller unit 41 as a medium feeding unit is disposed above the bottom 421 of the bank separation unit 42 provided continuously to the rear portion of the paper feed tray 40, and is disposed so as to be pivotable up and down with respect to the paper feed tray 40 and the like. The sheet is lowered and frictionally fed to the sheet stored in the sheet feed tray 40 or the like.

  The retard separation unit 43 is substantially constituted by a retard roller unit 43a and a front paper return unit 43b that pushes back the lower layer paper separated by the retard roller unit 43a. The retard roller unit 43 a is disposed so as to be able to contact the intermediate roller 45, and the multi-layer paper that cannot be separated by the bank separation unit 42 is frictionally separated by the retard roller unit 43 a and the intermediate roller 45. The front paper return unit 43b is formed in a claw shape and is disposed in the vicinity of the retard roller unit 43a. The lower paper separated by the retard roller unit 43a is hung on the claw and pushed back to the bank separation unit 42 side. It has become.

  The assist roller 46 is disposed so as to be always in contact with the intermediate roller 45 at a position slightly above and to the left of the intermediate roller 45, and sandwiches the uppermost sheet separated by the retard roller unit 43a with the intermediate roller 45. Then, the paper is reversed into a U shape, and the paper is fed to the platen 55. As shown in FIG. 5, the paper feed path through which the paper is conveyed includes a reversing portion formed along the outer peripheral surface (left half) of the intermediate roller 45, and the assist roller 46 is disposed in the latter half of the reversing portion. Has been. On the other hand, the retard roller unit 43a described above is disposed in the first half of the reversing portion of the paper feed path. That is, the retard roller unit 43a is disposed in the first halfway of the reversing part of the paper feed path so as to be able to contact the intermediate roller 45, and the assist roller 46 that is always in contact with the intermediate roller 45 is disposed in the second half of the reversing part. Yes. Thus, the paper that is reversed and fed along the outer peripheral surface of the intermediate roller 45 is nipped by the intermediate roller 45 and the retard roller unit 43a in the first half of the reversing unit, and is nipped by the intermediate roller 45 and the assist roller 46 in the second half of the reversing unit. Therefore, it is possible to stably feed the paper through the substantially U-shaped paper feed path.

  As shown in FIG. 3, the front EJ 145 includes a first paper discharge roller 48a, a first jagged roller 49a, a second paper discharge roller 48b, a second jagged roller 49b, and the like. The first paper discharge roller 48a is disposed on the downstream side of the transport of the platen 55, and the paper passing through the platen 55 is sandwiched and discharged together with the first knurled roller 49a. Further, the second paper discharge roller 48b is The paper is disposed downstream of the first paper discharge roller 48a, and the paper is nipped together with the second jagged roller 49b to be discharged onto the paper discharge tray 143.

  Next, the recording unit 150 will be described with reference to FIGS. As shown in FIG. 3, the recording unit 150 includes a paper feed roller 51 that feeds paper in the sub-scanning direction in synchronization with the recording operation, a driven roller 52, and a carriage 53 that moves in the main scanning direction in synchronization with the recording operation. A recording head 54 that ejects ink in synchronization with the recording operation, a platen 55 that holds the paper during recording flat, and the like are provided.

  As shown in FIG. 3, the paper feed roller 51 is arranged on the upstream side of the platen 55, and is fed reversely from the paper feed tray 40 via the paper fed by the paper feed roller 37 or the intermediate roller 45. The paper to be fed is nipped together with the driven roller 52 by the paper feeding mechanism 56 shown in FIG. The carriage 53 is inserted into the carriage guide shaft 57 shown in FIG. 3 above the platen 55 and connected to the carriage belt 58 (see FIG. 2). When the carriage belt 58 is operated by the carriage motor 59 shown in FIG. The carriage belt 58 is entrained by the movement of the carriage belt 58 and guided back and forth by the carriage guide shaft 57.

  As shown in FIG. 3, the recording head 54 is mounted on the carriage 53 so as to be spaced from the platen 55 by a predetermined distance. For example, a black ink recording head for discharging black ink, yellow, cyan, light cyan, And a plurality of color ink recording heads for ejecting magenta and light magenta inks, respectively. The recording head 54 is provided with a pressure generating chamber and a nozzle opening connected to the pressure generating chamber. The size of the recording head 54 is controlled from the nozzle opening toward the sheet by storing ink in the pressure generating chamber and pressurizing the ink with a predetermined pressure. Ink droplets are discharged.

  In such a configuration, an operation in the case of recording on a sheet by the inkjet multifunction peripheral 100 will be described. The user stores a plurality of sheets of paper before recording in the paper feed tray 40 or the like and activates the inkjet type multifunction peripheral 100. The paper stacked and stored in the paper feed tray 40 and the like is pushed out by the pickup roller unit 41, and the leading edge of the pushed-out paper abuts against the bank inclined portion 420 to perform frictional separation. The sheet is fed to the provided intermediate roller 45 side. At this time, the multi-layer paper that could not be separated by the bank separation unit 42 is separated again by the retard roller unit 43 a driven by the paper return shaft 72 and the intermediate roller 45, and the uppermost paper is fed by the intermediate roller 45. Then, the separated lower layer paper is pushed back to the paper feed tray 40 side by a paper return 71 driven by a paper return shaft 72. The fed paper is skewed and cueed, and is nipped by the paper feed roller 51 driven by the paper feed mechanism 56 and its driven roller 52 and fed to the platen 55.

  The sheet fed to the platen 55 is recorded by a recording head 54 mounted on a carriage 53 scanned by a carriage motor 59 and a carriage belt 58. At this time, the control unit of the inkjet multifunction peripheral 100 supplies each color ink to the recording head 54 from a total of seven ink cartridges, for example, yellow, magenta, light magenta, cyan, light cyan, and black. By controlling the driving of the carriage 53 and the paper feed roller 51, highly accurate ink dot control, halftone processing, and the like are executed. The paper on which recording has been completed is sandwiched between the first paper discharge roller 48a and the first jagged roller 49a, the second paper discharge roller 48b and the second jagged roller 49b driven by the paper feed mechanism 56, and the paper supply / discharge unit 140. And is stacked and placed on a paper discharge tray 143.

  Next, the separation of the double-fed paper in the bank separation unit 42 will be described. As shown in FIG. 3, the sheets correctly placed on the sheet feeding tray 40 and the like are stacked and stored with the leading end thereof in contact with the bank inclined portion 420 (each top surface of the rib 422). The pickup roller unit 41 pushes and feeds the uppermost sheet in the left direction in FIG. 3 while pressing the uppermost sheet from above. At this time, on the uppermost sheet, the static load and biting load in the vertical direction received from the pickup roller unit 41, the propulsive force in the horizontal direction (left direction in FIG. 3), and the bank reaction force (from the bank inclined portion 422) Contact load), frictional resistance with the lower layer paper, and the like are applied. Further, the lowermost sheet receives a vertically downward load received from the pickup roller unit 41, and a large frictional resistance force is generated between the lower surface of the sheet and the upper surface (pad surface) of the friction pad 423. The load of the pickup roller unit 41, the inclination angle of the bank inclined portion 420, etc. so that only the uppermost sheet is fed up the bank inclined portion 420 while considering the action of various forces acting on these uppermost sheets. Is set in a suitable state. As a result, when the pickup roller unit 41 is driven and sheet feeding is started, only the uppermost sheet is shifted upward by the bank inclined portion 420 and fed to the retard separation unit 43.

  Next, the characteristic part of this invention is demonstrated in detail with reference to FIGS.

  FIG. 7 is an enlarged side sectional view showing the bank separation part 42 and the pickup roller unit 41. FIG. 8 is an enlarged side sectional view showing the bank separation part 525 (comparative example) and the pickup roller unit 41. The pickup roller unit 41 shown in FIG. 7 and FIG. 8 is in a lowered state for paper feeding, and when the paper is set (stored), the paper is set with the pickup roller unit 41 raised.

  As shown in FIG. 7, the friction pad 423 constituting the characteristic part of the present invention is a plate-like pad (see FIG. 6) formed in a substantially rectangular shape, and is bent halfway as shown in FIG. It has a shape. The friction pad 423 is disposed so that the feed downstream pad surface 423a that can contact the pickup roller unit 41 (pickup roller 41a) is parallel to the bottom 421. The bank 423b is embedded in the bank separation unit 42 (medium feeding means) so that the surface 423b is under the bottom 421. Further, the feeding downstream side pad surface 423 a of the friction pad 423 protrudes from the upper surface of the bottom portion 421.

  On the other hand, the friction pad 523 shown in FIG. 8 is a flat pad formed in a substantially rectangular shape and is a first comparative example of the friction pad 423. The friction pad 523 is disposed on the bank separation portion 525 so that the upper surface (pad surface 523 a) thereof is parallel to the bottom portion 521 and protrudes from the upper surface of the bottom portion 521. Note that the bank separating unit 525 shown in FIG. 8 is the same as the bank separating unit 42 according to the present embodiment except that the bank-shaped friction pad 523 (first comparative example) is included. As described above, since the friction pad 523 protrudes from the upper surface of the bottom portion 521, when the paper is entered from the left direction in FIG. 8 into the bank separation unit 525 and set, the leading edge of the paper is in contact with the side surface of the friction pad 523. collide. For this reason, it becomes difficult to set the paper in the correct state, and when the paper is not set in the correct state, for example, it becomes difficult to separate and feed the paper in the bank separation unit 525.

  On the other hand, in the friction pad 423 (see FIG. 7) according to the present embodiment, the feeding downstream pad surface 423a protrudes from the upper surface of the bottom portion 421, but the feeding upstream pad surface 423b is a slant or circle with a gentle inclination. A peripheral surface is formed and is under the bottom portion 421. Thus, when the sheets P11 and P12 (upper layer is P11 and lower layer is P12) are set to enter from the left direction in FIG. 7, the leading edge of the sheet does not collide with the side surface of the friction pad 423. Further, since the feeding downstream pad surface 423a protrudes from the upper surface of the bottom portion 421 and can contact the pickup roller 41a, the sheets P11 and P12 are surely placed on the feeding downstream pad surface 423a and the roller surface of the pickup roller 41a. The paper is nipped and fed. That is, the upper layer paper P11 is fed by the pickup roller 41a, but the lower layer paper P12 is not fed by the action of the frictional force with the feeding downstream pad surface 423a (see FIG. 7). As described above, since the sheets P11 and P12 are securely held between the feeding downstream pad surface 423a and the pickup roller 41a, the sheet feeding device 142 according to the present invention reliably feeds and separates the sheets. Is possible.

  FIG. 9 is an enlarged side sectional view showing the friction pad 623 (second comparative example) and the pickup roller unit 41. Similar to the friction pad 523, the friction pad 623 is a pad on a flat plate formed on a rectangle, and is a second comparative example of the friction pad 423. The friction pad 623 is inclined so as to be lowered from the feeding downstream side to the feeding upstream side, and the feeding downstream end portion 623 a protrudes from the bottom portion 621, but the feeding upstream end portion 623 b is below the bottom portion 621. Lurking. Thus, the friction pad inclined with respect to the feeding surface (bottom portion 621) is, for example, employed in the rear ASF 34.

  As described above, the friction pad 623 is arranged so that the feeding upstream end 623b is under the bottom 621, similarly to the friction pad 423 of the present embodiment. , 22 (the upper layer is P21 and the lower layer is P22), the tips of the sheets P21 and 22 do not collide with the side surface of the friction pad 623. For this reason, although the sheet setting property is improved, unlike the friction pad 423, the pad surface 623c of the friction pad 623 contacting the pickup roller 41a is not parallel to the bottom 621 but inclined. As a result, the biting load of the pickup roller 41a acting on the papers P21 and 22 is increased, and the balance of the action of the various forces that have been assumed is lost, resulting in double feeding of paper. In particular, when the number of stored sheets decreases, such double feeding occurs. Next, the cause of the double feeding of the paper accompanying the increase in the biting load will be described with reference to FIG.

  FIG. 10 is a conceptual diagram for explaining a calculation formula relating to the biting load acting on the paper P11 on the friction pad 423. FIG. S1 is a static load applied to the friction pad 423 by the pickup roller unit 41 via the paper P11, S2 is a biting load generated vertically downward by the rotation (moment) of the pickup roller 41a, and μ is a surface of the pickup roller 41a. The coefficient of friction with the fed paper P11, θ, is a straight line connecting the rotation center point 41b of the pickup roller unit 41 to the NIP point (contact point between the pickup roller 41a and the friction pad 423) and the downstream pad of the friction pad 423. An angle formed with the surface 423a is used.

  As shown in FIG. 10, when the paper P11 is fed, a biting load S2 generated by the counterclockwise rotation of the pickup roller 41a in contact with the paper P11 is applied to the paper P11. Although the static load S1 of the pickup roller unit 41 acts together with the biting load S2, the static load S1 is not shown because it is canceled out by the reaction force from the friction pad 423. In addition, the propulsive force F that feeds the paper P11 by the rotation of the pickup roller 41a that is in contact acts in the right horizontal direction (the direction of the bank inclined portion 420) that is the paper feeding direction. The propulsive force F at this time is a product obtained by multiplying the resultant force of the static load S1 and the biting load S2 by the friction coefficient μ (F = μ (S1 + S2)).

The balance of force at this time will be considered in the radial direction from the NIP point to the rotation center point 41b and the tangential direction perpendicular thereto. The resultant radial force of the biting load S2 and the propulsive force F is offset by a reaction force (not shown) received from the mounting portion of the pickup roller unit 41, but the tangential direction is equal to the tangential component f of the propulsive force F and the biting load S2. The tangential direction component s2 is balanced (f = s2). That is, the following formula (1) is established.
μ (S1 + S2) * sin θ = S2 * cos θ (1)
When Expression (1) is transformed into an expression indicating the relationship between the static load S1 and the biting load S2, Expression (2) is obtained.
S2 = {μ * tan θ / (1-μ * tan θ)} S1 (2)
From equation (2), it can be seen that as the angle θ increases, the biting load S2 also increases. That is, in the friction pad 623 shown in FIG. 9, since the pad surface 623c is inclined with respect to the bottom portion 621, the angle formed between the straight line connecting the rotation center point 41b and the NIP point and the pad surface 623c increases. The biting load S2 increases. FIG. 9 shows a case where two sheets of paper P21 and 22 are stored, and the inclination of the pad surface becomes a problem when a small number of sheets are stored in this way.

  When a large number of sheets are stored (see, for example, FIG. 3), the uppermost sheet is hardly affected by the inclination of the pad surface, so that the uppermost sheet is substantially parallel to the bottom 421 (621). . At this time, the pickup roller 41a that contacts the uppermost sheet is at a position higher than the upper surface of the bottom 621 by the thickness of the stored sheet, so that the point where the pickup roller 41a contacts the sheet (hereinafter referred to as “sheet contact”). And the angle between the straight line connecting the rotation center point 41b and the upper surface of the sheet is small. When paper is fed, the position of the pickup roller 41a is lowered by the thickness of the fed paper, and the angle between the straight line connecting the rotation center point 41b and the paper contact and the paper upper surface slightly increases. Further, when the paper feeding progresses and a small number of sheets are stored, the position of the pickup roller 41a is lowered by the thickness of the fed sheet, and is also affected by the inclination of the pad surface described above. As a result, the angle formed by the straight line connecting the rotation center point 41b and the sheet contact point and the sheet upper surface increases. As the angle increases, the biting load S2 increases, so that the balance state in which good paper feeding has been performed is lost and double feeding of paper occurs.

  On the other hand, in the friction pad 423 (see FIG. 7) according to this embodiment, the feeding downstream pad surface 423a protrudes in parallel from the upper surface of the bottom portion 421. For this reason, the fed paper is always maintained in parallel with the bottom 421 and the feed downstream side pad surface 423a, and an increase in the angle between the straight line connecting the rotation center point 41b and the paper contact and the top surface of the paper is suppressed. be able to. Thereby, even in a state where a small number of sheets are stored, an increase in the biting load S2 is suppressed, and the occurrence of double feeding can be prevented by maintaining a balanced state in which good paper feeding / separation is performed. It becomes possible.

  FIG. 11 is an enlarged side sectional view showing the friction pad 723 (third comparative example) and the pickup roller unit 41. Similar to the friction pads 523 and 623, the friction pad 723 is a flat pad formed in a substantially rectangular shape, and is a third comparative example of the friction pad 423. Similar to the friction pad 523, the friction pad 723 is disposed so that the pad surface 723 a is parallel to the bottom portion 721 and protrudes from the bottom portion 721. Further, the bottom 721 on which the friction pad 723 is disposed is characterized in that a convex portion 721a higher than the pad surface is formed on the upstream side of the friction pad 723. Due to the shape of the bottom 721, when the sheets P31 and 32 (the upper layer is P31 and the lower layer is P32) are entered from the left direction in FIG. 11, the convex portion 721a on the bottom 721 is the leading edge of the sheets P31 and 32 and the friction pad. Since the collision with the side surface of 723 is prevented, the sheet setting property is improved. However, when the strong paper P31, 32 is fed, a gap is generated between the paper P32 and the friction pad 723 (pad surface 723a) (see FIG. 11), and the frictional force between the friction pad 723 and the paper P32 is reduced. Therefore, the sheet P32 may be fed along with the sheet P31.

  On the other hand, the friction pad 423 (see FIG. 7) according to the present embodiment has the feeding downstream side pad surface 423a formed in parallel with the upper surface of the bottom portion 421, so that even when a strong paper is fed. The frictional force between the friction pad 423 and the paper does not decrease, and it is possible to reliably prevent the double feeding of the paper as described above.

  As described above, the embodiment of the present invention has been described. According to the present invention, the feeding downstream pad surface 423a of the friction pad 423 is formed in parallel with the bottom 421 (medium storage surface) of the bank separation unit 42, and the friction pad. The feed upstream side pad surface 423b of 423 is formed in a shape recessed from the bottom 421. This improves the setability for storing paper in the paper feed tray 40 or the like (medium storage means), facilitates correct paper storage, and prevents the front end of the paper from being scratched or broken. Become. Further, since the feeding downstream pad surface 423a is formed in parallel with the bottom portion 421, an increase in the biting load S2 is suppressed, and a small number of sheets are stored in the sheet feeding tray 40 or the like (sheet storing section). However, it is possible to prevent double feeding.

  In addition, according to the present invention, the feeding upstream pad surface 423b is a surface including an inclined surface or a circumferential surface, so that the paper (medium) is smoothly stored in the paper feed tray 40 or the like (medium storage means). Therefore, it is possible to improve the paper setting property.

  Further, according to the present invention, the feeding upstream side of the friction pad 423 is embedded in the bottom portion 421 (medium storage means), so that it is possible to improve the sheet setting property while effectively using the space. .

  Further, according to the present invention, since the pickup roller 41a (medium feeding means) abuts on the feeding downstream side pad surface 423a, the sheet (medium) is sandwiched between the pickup roller 41a and the feeding downstream side pad surface 423a. Thus, it is possible to reliably feed / separate the paper and improve the paper feeding performance.

  Note that the scope of the present invention is not limited to the above-described embodiments, and can be applied to various other embodiments as long as they do not contradict the description of the claims. For example, in the present embodiment, the paper feeding device 142 in the paper feeding / discharging unit 140 has been described. However, the present invention can be widely applied to any medium feeding device that feeds a medium.

  Any recording apparatus provided with a medium feeding device can be applied to, for example, a facsimile machine, a copying machine, and the like. In addition to a recording apparatus, the meaning of a liquid ejecting apparatus that ejects a liquid corresponding to its use from a liquid ejecting head onto an ejected medium instead of ink and attaches the liquid to the ejected medium is, for example, a liquid crystal display or the like Color material jet head used for manufacturing color filters, electrode material (conductive paste) jet head used for electrode formation for organic EL display and surface emitting display (FED), bio-organic jet head used for biochip manufacturing, precision pipette The present invention can also be applied to an apparatus equipped with a sample ejection head or the like.

1 is a perspective view showing an overall appearance configuration of an inkjet multifunction peripheral 100 that is one of recording apparatuses according to an embodiment of the present invention. 2 is a perspective view showing an internal structure of the inkjet type multifunction peripheral 100. FIG. 1 is a schematic side view of an inkjet type multifunction peripheral 100. FIG. It is a side view which shows the detail of the paper support 33 and rear ASF34. It is a side view which shows the detail of front ASF144. It is a perspective view which shows the bank separation part. FIG. 4 is an enlarged side sectional view showing a bank separation unit and a pickup roller unit 41. 4 is an enlarged side sectional view showing a bank separating unit 525 (comparative example) and a pickup roller unit 41. FIG. 4 is an enlarged side sectional view showing a friction pad 623 (second comparative example) and a pickup roller unit 41. FIG. FIG. 10 is a conceptual diagram for explaining a calculation formula regarding a biting load acting on a sheet P11 on a friction pad 423. FIG. 9 is an enlarged side sectional view showing a friction pad 723 (third comparative example) and a pickup roller unit 41.

Explanation of symbols

31 Rear paper feed port, 32 frame, 33 paper support, 34 rear ASF, 35a movable edge guide, 35b fixed edge guide, 36 hopper, 37 paper feed roller, 40 paper feed tray, 41 pickup roller unit, 41a pickup roller, 42 525 Bank separation unit, 43 retard separation unit, 43a retard roller unit, 43b front paper return unit, 45 intermediate roller, 46 assist roller, 51 paper feed roller, 52 driven roller, 55 platen, 100 inkjet compound machine, 110 printer , 120 scanner, 130 paper feed unit, 140 paper feed / discharge unit, 141 front paper feed / discharge port, 142 paper feeding device, 143 paper discharge tray, 144 front ASF, 145 front EJ, 150 recording unit, 420, 520, bank Inclined part, 4 21, 521, 621, 721 Bottom, 422, 522 Rib, 423, 523, 623, 723 Friction pad, 423a Feed downstream pad surface, 423b Feed upstream pad surface

Claims (6)

Medium storage means for storing the medium;
Medium feeding means for feeding the medium,
A medium feeding device in which a pad for feeding the medium sandwiched with the medium feeding means is disposed in the medium storage means,
The pad supply downstream pad surface of the pad is formed in parallel with the medium storage surface of the medium storage means, and the pad upstream supply pad surface of the pad is formed in a shape recessed from the medium storage surface. A medium feeding device. The medium feeding device according to claim 1, wherein the feeding upstream pad surface is a surface including an inclined surface or a circumferential surface. The medium feeding device according to claim 1, wherein a feeding upstream side of the pad is embedded in the medium housing unit. The medium feeding device according to claim 1, wherein the medium feeding unit abuts on the pad surface on the downstream side of feeding. A recording device for recording on a medium,
A recording apparatus comprising the medium feeding device according to claim 1. A liquid ejecting apparatus that ejects liquid onto an ejection target medium,
A liquid ejecting apparatus comprising the medium feeding device according to claim 1.

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