JP3760974B2 - Roller support device, recording medium feeding device, and recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a roller support device for preventing a drive roller of a printer or the like from bending, a recording medium feeding device including the roller support device, and a recording device.
[0002]
[Prior art]
FIG. 6 shows a paper feed mechanism in a conventional printer. A recording medium paper feeding device 100 for feeding a sheet 113 such as paper mainly includes a long cylindrical driving roller 101 rotated by driving means (not shown) and a driven roller 105 driven by the rotation of the driving roller 101. As a component. A platen 107 is provided on the downstream side of the driving roller 101, and a print head 109 is provided above the platen 107. Furthermore, a discharge roller 111 for discharging the printed sheet 113 is provided on the downstream side of the print head 109. The sheet 113 is fed forward (leftward in the figure) by the rotational driving of the driving roller 101, printed by the print head 109 on the platen 107, and then discharged to the outside of the printer by the discharge roller 111.
[0003]
In such a mechanism, with recent printers demanding high-quality printing similar to photographs, the recording medium feeding apparatus 100 has been required to have high paper feeding accuracy. In order to satisfy this requirement, a structure in which the driven roller 105 is pressed against the driving roller 101 with a strong load so that the driving roller 101 is firmly attached to the sheet 113 has been adopted. As indicated by a broken line in the figure, a new problem arises that the central portion of the long drive roller 101 is slightly bent downward.
[0004]
In other words, the sheet 113 should originally follow a path parallel to the upper surface of the platen 107 as indicated by a solid line, but the sheet 113 is placed under the platen 107 as indicated by a broken line when the driving roller 101 is bent. It will progress so as to float upwards. Therefore, the sheet 113 that has just been printed by the print head 109 touches and rubs against the head surface 115 of the print head 109, and the print surface becomes dirty.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a roller support device that prevents the drive roller from being bent even when the driven roller is pressed against the drive roller with a strong load, and a paper feeding medium feeding device and a recording device including the roller support device. is there.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present application is a roller support device that supports a driving roller that receives a pressing load by a driven roller at a position opposite to the driven roller. A rotation roller that is rotatably contacted with the surface and is rotatably supported so as to maintain a rotation axis parallel to the rotation axis of the drive roller, and is parallel to the rotation axis of the drive roller inside the frame. The frame has two support shafts, and each of the support shafts is provided with the rotating roller, and is between the two support shafts and corresponds to the longitudinal center of the rotating roller. And a rotation roller support member that is rotatably supported by a rotation support portion that is biased toward the drive roller by a force that opposes the pressing load of the driven roller. To do It is.
[0007]
According to the present invention, since the rotating roller supports the pressing load of the driven roller exerted on the driving roller from the opposite side of the driving roller with the force opposed to the pressing load, the driving roller bends due to the pressing load of the driven roller. Disappears. As a result, the sheet passing between the driving roller and the driven roller travels through a predetermined path. In addition, since the rotating roller is rotatably in contact with the peripheral surface of the driving roller, when the driving roller rotates, no friction occurs between the peripheral surface of the driving roller and the rotating roller, and the surface of the driving roller is damaged. In addition, no extra burden is placed on the drive source that drives the drive roller.
[0008]
The invention according to claim 1 includes a rotating roller support member, and the rotating roller support member has two support shafts parallel to the rotation axis of the drive roller inside the frame, The rotation roller is provided on a support shaft, and the rotation roller support member is located between the two support shafts and at the position of the frame corresponding to the longitudinal center of the rotation roller. It is characterized in that it is rotatably supported by a rotation support portion that is biased toward the drive roller by a force that opposes a pressing load by a driven roller.
[0009]
According to the present invention, the rotating rollers provided on the two support shafts come into contact with the peripheral surface of the driving roller at two parallel linear portions and stably support the driving roller. Even when the drive roller is tilted, the rotation roller support member rotates around the rotation support portion according to the tilt, so that the axis of the drive roller and the axis of the rotation roller always maintain a parallel relationship. be able to. Therefore, the load applied to the driving roller can always be supported on average by the entire length of the rotating roller.
[0010]
The invention according to claim 2 of the present application is the roller support device according to claim 1, wherein the two support shafts are supported by the frame body at both ends and the center of the support shaft, and the rotation One roller is provided in each of the support shafts in regions separated by both ends of the support shaft and a central support portion.
[0011]
When one long rotating roller is provided on one support shaft, the contact portion of the rotating roller with the driving roller is unlikely to be parallel (straight) over the entire length, and the load applied to the driving roller is averaged over the entire length of the rotating roller. However, according to the present invention, since each rotary roller is short, the contact portion between each rotary roller and the drive roller tends to be linear, and the average surface surface of the rotary roller. The drive roller can be supported by
[0012]
According to a third aspect of the present invention, in the roller support device according to the first or second aspect, a substrate that is fixedly provided with respect to the position of the driving roller, and a substrate that is rotatable with respect to the substrate. And a rotation plate on which the rotation support portion is formed. The rotation plate is urged toward the driving roller by a force of the rotation support portion facing a pressing load by the driven roller. Further, the substrate is urged to rotate with respect to the substrate.
[0013]
According to the present invention, the rotation urging is performed on the opposite side of the rotation support portion around the rotation fulcrum of the rotation plate, and as a result, the rotation support portion can be urged toward the drive roller. .
[0014]
Further, in the invention according to claim 4 of the present application, in the roller support device according to any one of claims 1 to 3, the rotating roller is in contact with a central portion in the longitudinal direction of the driving roller. It is characterized by. According to the present invention, the central portion of the driving roller in the longitudinal direction is most easily bent, and by supporting this with the rotating roller, the entire bending of the driving roller can be eliminated.
[0015]
According to a fifth aspect of the present invention, in the roller support device according to any one of the first to fourth aspects, the driving roller and the driven roller are for supplying a sheet to a printing unit in a printer. It is a drive roller and a driven roller immediately before the printing unit. According to the present invention, since the driving roller is not bent due to the pressing load of the driven roller, the sheet that has passed between both rollers advances straight on the platen. Therefore, the printed sheet does not rub against the print surface by touching the head and the print surface is not stained.
[0016]
The invention according to claim 6 includes a driving roller that is rotated by driving means, and a driven roller that is driven by the driving roller, and the recording medium is sandwiched between the two rollers and sent to the other side. The recording medium feeding device includes the roller support device according to any one of claims 1 to 5. According to this invention, the effect of each invention of the said roller support apparatus is obtained similarly.
[0017]
According to a seventh aspect of the present invention, in the recording medium feeding device according to the sixth aspect, the driving roller is formed by integrally attaching a high friction layer on a surface of a high-rigidity roller base. The high-friction layer is a coating that holds the wear-resistant particles and the wear-resistant particles uniformly in a state where a part of the tip side in the radial direction of the high-rigidity roller is exposed on the surface. It is characterized by having a layer.
[0018]
The driving roller having this structure has high paper feeding accuracy due to the high friction layer on the surface thereof, and the driven roller is pressed by a strong load. Therefore, the effect of applying the roller support device to the drive roller having this structure is remarkable.
[0019]
Further, the present invention described in claim 8 is a printing unit and a recording medium feeding device for feeding the recording medium toward the downstream, a printing unit, and a discharge roller for discharging the printed recording medium to the outside. And a recording medium feeding device according to claim 6 or 7.
[0020]
According to the present invention, it is possible to reliably prevent the drive roller of the recording medium feeding apparatus from being bent, so that it is possible to improve the paper conveyance accuracy and reduce the occurrence of the problem that the paper touches the recording head surface and becomes dirty. it can.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a schematic side view showing an example of a printer to which a roller support device according to the present invention can be applied. FIG. 2 is a side view showing a state in which a driving roller is supported by the roller support device of the present invention. FIG. 4 is a front view showing a state in which the driving roller is supported by the roller support device, FIG. 4 is a sectional view of the driving roller cut along a plane parallel to the axis, and FIG. 5 is a front view of the rotating roller support member.
[0022]
Before describing the characteristic configuration of the present invention, first, the configuration of the printer 1 will be briefly described with reference to FIG. The printer 1 includes a sheet supply unit 3 that sends out the sheet S, a printing unit 4 that discharges ink onto the surface of the sent sheet S to form characters and images, and a discharge roller 5 that discharges the printed sheet S. It has.
[0023]
The sheet supply unit 3 includes a supply roller 7, a hopper 6 that urges the sheet S toward the supply roller 7, and a separation pad 9 that nips the sheet S between the supply roller 7 and separates the sheet S. It has. A plurality of sheets S are set in the hopper 6, and when the sheets are supplied, the sheets S are pressed by the hopper 6 toward the supply roller 7 that rotates once and separated by the separation pad 9, so that only one sheet S is provided. Is supplied to the printing unit 4 side.
[0024]
A lower guide 13 attached to the first sub-frame 11 and an upper guide 17 attached to the main frame 15 are provided on the downstream side of the supply roller 7, and the sheet S is guided by both the guides 13 and 17. Thus, the sheet conveying device 19 which is a recording medium feeding device is reached. The sheet conveying device 19 includes a driving roller 21 that is positioned below the conveying path of the sheet S and is rotated by driving means (not shown), and a driven roller 23 that is provided facing the upper side.
[0025]
As shown in FIG. 4, the drive roller 21 has a high friction layer 26 integrally attached to the surface of a highly rigid roller base (free cutting steel or the like) 24. The high friction layer 26 has an average particle diameter of 20 μm. ~ 70 μm wear-resistant particles 28 and the wear-resistant particles 28 are uniformly dispersed (distribution density with respect to the area of the surface of the high friction layer is 20% to 80%), and one end side in the roller radial direction of the particles. And an adherent layer 30 that firmly holds the portion exposed on the surface. In the present embodiment, the wear-resistant particles 28 are made of a ceramic such as alumina or silicon carbide, and the adherend layer 30 is made of an acrylic adhesive.
[0026]
On the other hand, the surface of the driven roller 23 that is in contact with the sheet S is composed of a low friction member, and the low friction member is a fluorine-containing thermoplastic elastomer made of a composition mainly composed of a thermoplastic elastomer and a fluororesin. In the present embodiment, the fluorine-containing thermoplastic elastomer is mainly composed of a thermoplastic polyurethane elastomer and a fluororesin. Specifically, the thermoplastic polyurethane elastomer component is 85 to 90% by weight, and the polytetrafluoroethylene component is 10 to 15% by weight. Here, the thermoplastic polyurethane elastomer component is a polyol-based multi-block polymer obtained by polycondensation of diisocyanate, high molecular weight polyol and low molecular weight polyol.
[0027]
The driven roller 23 is rotatably supported at the tip of the upper guide 17 in a state parallel to the axis of the drive roller 21, and the upper guide 17 is rotatably attached to the support shaft 25. Since the torsion spring 27 is provided on the support shaft 25, the distal end portion 29 of the torsion spring 27 acts on the distal end side of the upper guide 17 and constantly urges the upper guide 17 toward the drive roller 21 ( In this example, it is pressed with a force of about 4.7 kgf). As a result, the sheet S passing through the sheet conveying device 19 can be pressed toward the driving roller 21, and a driving force can be applied to the sheet S and sent out to the printing unit 4.
[0028]
The printing unit 4 includes a carriage 33 supported by the main frame 15 and the carriage guide shaft 31, and a print head 35 is attached to the lower portion of the carriage 33. An ink cartridge 37 is mounted on the carriage 33. The carriage 33 is movable in the main scanning direction, which is a direction orthogonal to the paper surface, and the printing operation is performed by printing one scan by ejecting ink from the print head 35 as the carriage 33 moves. Each time printing for one scan is performed, the sheet conveying device 19 sends the sheet S forward by a predetermined pitch. A platen 39 is provided at a position facing the print head 35. The platen 39 supports and guides the lower surface of the sheet S and functions to define the interval between the sheet S and the print head 35.
[0029]
Next, in the printer 1 as described above, a structure that prevents the driving roller 21 from being bent even if the driven roller 23 is strongly pressed against the driving roller 21 by the action of the torsion spring 27 is based on FIGS. 2 and 3. explain.
[0030]
As shown in FIG. 2, a roller support device 41 is provided below the drive roller 21. The roller support device 41 is provided with a plastic connection member 45 fixed to the substrate 43, and a rotation plate 49 is provided on a protrusion 47 formed on the connection member 45 in a rotatable state. Yes.
[0031]
Spring locking portions 51 and 53 are formed on the end portion of the substrate 43 and one end of the rotating plate 49, respectively, and both ends of the tension coil spring 55 are locked between the spring locking portions 51 and 53. Yes. Due to the action of the tension coil spring 55, the rotating plate 49 is always urged counterclockwise in FIG. A rotation restricting portion 57 is formed on the substrate 43 in order to restrict the rotation of the rotation plate 49 in a counterclockwise direction beyond a certain level.
[0032]
Further, a rotation support portion 59 is formed upward at the end of the rotation plate 49 opposite to the side where the spring locking portion 53 is formed. The tension coil spring 55 is always biased upward by the counterclockwise biasing force of the rotating plate 49. The upward biasing force of the rotation support portion 59, that is, the spring biasing force (spring constant) of the tension coil spring 55 is set to be almost the same as the pressing force with which the driven roller 23 is pressed against the driving roller 21 by the torsion spring 27. .
[0033]
As shown in FIGS. 2 and 3, a rotating roller support member 61 is rotatably supported by the rotation support portion 59 with the rotation support portion 59 as a rotation fulcrum. As shown in FIG. 5, the rotation roller support member 61 has support shafts 65 arranged in parallel to the plastic frame body 63 in two rows. Each support shaft 65 has both ends 69 and 71 of the frame body 63 and the frame. It is supported at the center 73 of the body 63. Two rotating rollers 67 are rotatably provided between the support positions of the support shafts 65. That is, a total of four rotating rollers 67 are arranged in the frame 63 in vertical and horizontal alignment, and a receiving hole 75 is formed in the bottom surface of the frame 63 at the center position of the four rotating rollers 67. The receiving hole 75 is for receiving the rotation support portion 59 of the rotation plate 49 in a rotatable state.
[0034]
Next, the relationship between the rotating roller support member 61 and the driving roller 21 will be described. As shown in FIG. 2, the peripheral surfaces of the rotating roller 67 provided in parallel with the two support shafts 65 are in contact with the peripheral surface of the driving roller 21 so as to be parallel to the axis of the driving roller 21. As shown in FIG. 3, the two rotating rollers 67 provided on the respective support shafts 65 are separated from each other, but the portions in contact with the driving roller 21 are located on the same straight line. Although not clearly shown in FIG. 3, the rotary roller support member 61 is positioned at the center of the drive roller 21 in the length direction.
[0035]
Further, as shown in FIG. 3, the rotation roller support member 61 is rotatably supported by the rotation support portion 59 of the rotation plate 49. Therefore, if the drive roller 21 is inclined or bent, Accordingly, the rotation roller support member 61 rotates about the rotation support portion 59 so that the two rotation rollers 67 can always come into contact with the drive roller 21 in a parallel state.
[0036]
Further, as described above, since the rotation support portion 59 of the rotation plate 49 is always urged upward by the action of the tension coil spring 55, when the driven roller 23 presses the drive roller 21 downward, This acts as a counter force against the pressing force of the driven roller 23. Therefore, the driving roller 21 is not bent by the pressing force of the driven roller 23. Further, when the driving roller 21 is rotating, the four rotating rollers 67 are freely rotated in accordance with the rotation, so that friction is generated between the peripheral surface of the driving roller 21 and the peripheral surface of the rotating roller 67. Thus, there is no possibility that the drive roller 21 is worn away due to wear or that an excessive load is applied to a drive motor (not shown) driving the drive roller 21.
[0037]
In the rotation roller support member 61 of the present embodiment, two rotation rollers 67 are attached to one support shaft 65. This is because, when one long rotating roller 67 is provided on one support shaft 65, the contact portion between the peripheral surface of the long rotating roller and the driving roller is not easily parallel over the entire length, and the long rotating roller This is because the support shaft 65 for that purpose can be supported only at both ends of the long rotating roller, and therefore the support shaft 65 may be bent.
[0038]
Of course, if the contact portion between the rotation roller and the driving roller can be made parallel over the entire length and a sufficiently strong support shaft 65 can be used, one long rotation roller 67 is provided on one support shaft 65. May be. Further, three or more rotating rollers 67 can be provided on one support shaft 65. In this case, it is preferable that a portion for supporting the support shaft 61 is formed in the frame 63 between the rotating rollers 67.
[0039]
Further, in this embodiment, the driving roller 21 is supported by the single rotating roller support member 61 at the center of the driving roller 21, but further on both sides of the rotating roller support member 61 supported at the center of the driving roller 21. The same rotation roller support member 61 may be provided as an auxiliary, or the same rotation roller support member 61 is provided one by one at a symmetrical position across the center of the drive roller 21 instead of the center of the drive roller 21. You may do it.
[0040]
In the above-described embodiment, the driving roller support device that receives a pressing load from the driven roller in the printer 1 has been described. However, the above-described device is also used in other devices such as a fax machine and a copying machine in which the driving roller and the driven roller are used. The rotating roller support member 61 may be provided in the same manner as in the embodiment.
[0041]
【The invention's effect】
According to the present invention, since the rotating roller supports the pressing load of the driven roller exerted on the driving roller from the opposite side of the driving roller with the force opposed to the pressing load, the driving roller bends due to the pressing load of the driven roller. Disappears. As a result, the sheet passing between the driving roller and the driven roller travels through a predetermined path. Further, since the rotating roller is rotatably contacted with the peripheral surface of the driving roller, when the driving roller rotates, friction due to rubbing does not occur between the peripheral surface of the driving roller and the rotating roller, and the surface of the driving roller. No extra load is placed on the drive source that drives the drive roller.
[0042]
The roller support device includes a rotation roller support member. The rotation roller support member has two support shafts parallel to the rotation axis of the drive roller on the inner side of the frame, and the rotation roller is provided on each support shaft. The rotating roller support member is subjected to a pressing load by the driven roller at a position of the frame body between the two support shafts and corresponding to a central portion in the longitudinal direction of the rotating roller. If it is supported so as to be able to rotate by the rotation support portion that is biased toward the drive roller by the opposing force, the rotation rollers provided on the two support shafts are arranged in two parallel straight lines. The drive roller can be stably supported by contacting the peripheral surface of the drive roller at the portion. Even when the drive roller is tilted, the rotation roller support member rotates around the rotation support portion according to the tilt, so that the axis of the drive roller and the axis of the rotation roller always maintain a parallel relationship. be able to. Therefore, the load applied to the driving roller can always be supported on average by the entire length of the rotating roller.
[Brief description of the drawings]
FIG. 1 is a side view of a printer to which a roller support device of the present invention can be applied.
FIG. 2 is a side view showing a state where a driving roller is supported by a roller support device of the present invention.
FIG. 3 is a front view showing a state where a driving roller is supported by a roller support device of the present invention.
FIG. 4 is a cross-sectional view of the drive roller cut along a plane parallel to the axis.
FIG. 5 is a front view of a rotating roller support member.
FIG. 6 is a side view of a printer showing problems in a conventional printer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 19 Sheet conveying apparatus 21 Drive roller 23 Driven roller 24 Roller base | substrate 25 Support shaft 26 High friction layer 27 Torsion spring 28 Abrasion resistant particle 29 Tip part 30 Deposited layer 41 Roller support apparatus 43 Board | substrate 45 Connection member 47 Protrusion part 49 Rotation Plates 51, 53 Spring locking portion 55 Pull coil spring 57 Rotation restricting portion 59 Rotation support portion 61 Roller member 63 Frame body 65 Support shaft 67 Rotating rollers 69, 71 Both ends 73 of frame body Center 75 of frame body Receiving hole

Claims (8)

A roller support device for supporting a driving roller that receives a pressing load by a driven roller at a position opposite to the driven roller;
A rotating roller that rotatably supports the peripheral surface of the drive roller and is rotatably supported so as to maintain a rotation axis parallel to the rotation axis of the drive roller;
Two support shafts parallel to the rotation axis of the drive roller are provided inside the frame, and each of the support shafts is provided with the rotation roller. The position of the frame corresponding to the central portion in the longitudinal direction of the roller is rotatably supported by a rotation support portion that is biased toward the driving roller by a force that opposes the pressing load by the driven roller. A roller support device comprising a rotating roller support member.   2. The two support shafts according to claim 1, wherein the two support shafts are supported by the frame body at both ends and a center of the support shafts, and the rotating roller is separated by support portions at both ends and the center of the support shafts in each support shaft. One roller support device is provided in each region.   3. The substrate according to claim 1, further comprising: a substrate fixedly provided with respect to the position of the driving roller; and a rotating plate provided rotatably with respect to the substrate and having the rotation support portion formed thereon, The rotation plate is urged to rotate with respect to the substrate so that the rotation support portion is urged toward the driving roller by a force opposed to the pressing load by the driven roller. Roller support device.   4. The roller support device according to claim 1, wherein the rotating roller is in contact with a central portion in a longitudinal direction of the driving roller. 5.   5. The roller support device according to claim 1, wherein the driving roller and the driven roller are a driving roller and a driven roller immediately before the printing unit for supplying a sheet to the printing unit in the printer. .   6. A recording medium feeding device comprising: a driving roller that is rotated by driving means; and a driven roller that is driven by the driving roller, wherein the recording medium is fed between the rollers while being fed between the rollers. A recording medium feeding device comprising the roller support device described in any one of the above items.   7. The drive roller according to claim 6, wherein a high friction layer is integrally attached to a surface of a high rigidity roller base, and the high friction layer uniformly disperses the wear resistant particles and the wear resistant particles. And a deposition layer that holds the particles firmly in a state in which a part of the tip side in the radial direction of the high-rigidity roller is exposed on the surface.   A recording apparatus comprising: a printing unit; a recording medium feeding device for feeding the recording medium toward the downstream side; a printing unit; and a discharge roller for discharging the printed recording medium to the outside. 7. A recording apparatus comprising the recording medium feeding apparatus described in item 7.

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