JP4506653B2 - Droplet discharge device - Google Patents

Description

  The present invention relates to a liquid droplet ejection apparatus that records an image by ejecting liquid droplets from a liquid droplet ejection head onto a recording medium conveyed by a conveyance unit.

  In an ink jet printer as a droplet discharge device, ink droplets are discharged from a recording head onto a sheet to record an image, and then a transfer mechanism (for example, refer to Patent Document 1) composed of a roll and a spur or a pair of transfer rolls. (For example, see Patent Documents 2 to 4) and the like. At this time, there is a problem of ink offset caused by contact of a spur or a roll with ink before drying, and various countermeasures have been devised so far.

  In Patent Document 1, the paper after image recording is transported while being sandwiched between a spur that contacts the recording surface and a roll that contacts the back surface, thereby reducing the contact area between the recording surface of the paper and the transport mechanism. The offset is suppressed. However, the nip force is weak compared to the conveyance of the paper by the conveyance roll pair, and high-speed conveyance is difficult. Further, since the conveyance accuracy is low, it is not suitable for conveying a sheet for a long distance, such as when performing double-sided printing.

  In Patent Documents 2 and 3, ink offset is suppressed by lowering the hardness of the roll contacting the recording surface of the paper. However, since the nip force is weaker than that of paper transport by a normal pair of transport rolls, it is not suitable for high-speed transport or long-distance transport as in Patent Document 1.

Further, in Patent Document 4, a roll that comes into contact with a recording surface of a sheet is covered with ceramic particles having a low ink adsorptivity to suppress ink offset. However, since a large nip force is applied to the recording surface of the paper, ink oozes out from the recording surface and the image is disturbed.
Japanese Patent Laid-Open No. 2002-175853 JP 2004-83216 A JP 2003-170634 A JP 7-137384 A

  The present invention has been made in consideration of the above facts, and suppresses the offset of the liquid from the recording medium to the roll, which occurs when the recording medium after image recording is conveyed by the conveying roll pair, and the recording by the conveying roll pair. The object is to improve the transport performance of the medium.

The droplet discharge device according to claim 1 includes a droplet discharge head that discharges droplets, a transport unit that transports a recording medium to face the droplet discharge head, and a downstream side of the transport unit in the transport direction. A droplet discharge device comprising: a pair of conveyance rolls that convey a recording medium; a first region of the pair of conveyance rolls that nips a non-recording region at both ends in the width direction of the recording medium; and the non-recording of a recording medium A second area of the conveying roll pair that nips the recording area on the inner side in the width direction of the area, and the conveying roll pair includes a driving roll that is rotationally driven, and a driven roll that is driven in pressure contact with the driving roll. The driven roll portion of the driven roll in the first region is fixed to the rotating shaft of the driven roll, and the driven roll portion of the driven roll in the second region is rotatably attached to the rotating shaft. , before Characterized in that the nip force in the second region of the transport rolls were lower than the nip force in the first region of the transport rolls.

  In the liquid droplet ejection apparatus according to the first aspect, the recording medium is conveyed by the conveying means so as to face the liquid droplet ejection head, and the liquid droplets are ejected from the liquid droplet ejection head to the recording medium to record an image. The recording medium after the image recording is transported by a pair of transport rolls on the downstream side of the transport unit in the transport direction.

  Here, the non-recording area at both ends in the width direction of the recording medium is nipped by the first area of the transport roll pair, and the recording area inside the width direction of the non-recording area of the recording medium is nipped by the second area of the transport roll pair. However, the nip force in the second region of the transport roll pair is lower than the nip force in the first region of the transport roll pair.

  As a result, the force applied to the recording area of the recording medium from the pair of conveyance rolls can be suppressed, and the conveyance force of the recording medium by the pair of conveyance rolls can be increased. The conveyance performance of the recording medium by the conveyance roll pair can be improved.

  The droplet discharge device according to claim 2 is the droplet discharge device according to claim 1, wherein hardness in the second region of at least one roll of the transport roll pair is set to the first region of the roll. It is characterized by being lower than the hardness in.

  The at least one roll of the pair of transport rolls of the droplet discharge device according to claim 2 has a second area that sandwiches the recording area of the recording medium rather than a first area that nips the non-recording area of the recording medium. However, the hardness is low. As a result, the nip force in the second region of the transport roll pair is lower than the nip force in the first region of the transport roll pair, so that the force applied to the recording area of the recording medium from the transport roll pair is suppressed and the transport roll The conveyance force of the recording medium by the pair can be increased. Therefore, the offset of the liquid from the recording medium to the roll can be suppressed, and the conveyance performance of the recording medium by the conveyance roll pair can be improved.

  The droplet discharge device according to claim 3 is the droplet discharge device according to claim 2, wherein the material of the second region of the roll is rubber and the material of the first region of the roll is the roll. The second region is made of rubber or metal having a hardness higher than that of the second region.

  In the droplet discharge device according to claim 3, the material of the second region of at least one roll of the pair of transport rolls is rubber, and the material of the first region of the roll is higher in hardness than the material of the second region of the roll. By using this rubber or metal, the hardness in the second region of the roll is lower than the hardness in the first region of the roll.

  The droplet discharge device according to claim 4 is the droplet discharge device according to claim 2 or 3, wherein the position of the first region of the roll can be changed according to the size of the recording medium. It is characterized by that.

  In the droplet discharge device according to the fourth aspect, the position of the first region having higher hardness than the second region is changed in accordance with the width of the recording medium in at least one roll of the transport roll pair. As a result, recording media of various sizes can be transported satisfactorily while suppressing liquid offset.

  The droplet discharge device according to claim 5 is the droplet discharge device according to claim 4, wherein the roll is provided for each size of the recording medium, and is switched according to the size of the recording medium. To do.

  In the droplet discharge device according to the fifth aspect, at least one roll of the pair of transport rolls is provided for each size of the recording medium, and is exchanged according to the width of the recording medium. As a result, the position of the first region of the roll having a high hardness is changed according to the width of the recording medium, so that recording media of various sizes can be transported satisfactorily while suppressing liquid offset.

  The droplet discharge device according to claim 6 is the droplet discharge device according to any one of claims 1 to 3, wherein an outer diameter of the at least one roll of the pair of transport rolls in the second region. Is made smaller than the outer diameter in the first region of the roll.

  In at least one roll of the transport roll pair of the droplet discharge device according to claim 6, the second area that nips the recording area of the recording medium is more than the first area that nips the non-recording area of the recording medium. The outer diameter is small. As a result, the nip force in the second region of the transport roll pair is lower than the nip force in the first region of the transport roll pair, so that the force applied to the recording area of the recording medium from the transport roll pair is suppressed and the transport roll The conveyance force of the recording medium by the pair can be increased. Therefore, the offset of the liquid from the recording medium to the roll can be suppressed, and the conveyance performance of the recording medium by the conveyance roll pair can be improved.

  The droplet discharge device according to claim 7 is the droplet discharge device according to claim 6, wherein the position of the first region of the roll can be changed according to the size of the recording medium. Features.

  In the droplet discharge device according to the seventh aspect, the position of the first region having a diameter larger than that of the second region is changed according to the width of the recording medium in at least one roll of the pair of transport rolls. As a result, recording media of various sizes can be transported satisfactorily while suppressing liquid offset.

  The droplet discharge device according to claim 8 is the droplet discharge device according to claim 7, wherein the roll is provided for each size of the recording medium and is switched according to the size of the recording medium. To do.

  In the droplet discharge device according to the eighth aspect, at least one roll of the pair of transport rolls is provided for each size of the recording medium, and is switched according to the width of the recording medium. As a result, the position of the large-diameter first region of the roll is changed in accordance with the width of the recording medium, so that recording media of various sizes can be transported satisfactorily while suppressing liquid offset.

  The droplet discharge device according to claim 9 is the droplet discharge device according to claim 7, wherein the first region is provided in one roll for each size of the recording medium, and the rolls on both sides of the roll are provided. The outer diameter of the first area between the first areas can be reduced to be equal to or smaller than the outer diameter of the second area of the roll, and the outer diameter of the first area of the roll facing the recording surface of the recording medium is The roll is reduced to be equal to or smaller than the outer diameter of the second region of the roll.

  In the droplet discharge device according to the ninth aspect, the first area is provided for each size of the recording medium on one roll constituting the pair of transport rolls. Here, the outer diameter of the first area between the first areas on both sides of the roll can be reduced to be equal to or smaller than the outer diameter of the second area of the roll, and the outer diameter of the recording medium faces the non-recording area. The outer diameter of the first region of the roll is reduced to be equal to or smaller than the outer diameter of the second region of the roll.

  As a result, the position of the large-diameter first region of the roll is changed in accordance with the width of the recording medium, so that recording media of various sizes can be transported satisfactorily while suppressing liquid offset.

  The droplet discharge device according to claim 10 is the droplet discharge device according to any one of claims 6 to 9, wherein the first region and the second region of the roll are individually rotated. It is possible to do this.

  In at least one roll of the transport roll pair of the droplet discharge device according to claim 10, the outer diameter of the second region is smaller than that of the first region.

  Here, since the 1st area | region and 2nd area | region of the said roll can be rotated separately, a speed difference does not arise in the circumferential speed of the 1st area | region of the said roll, and the circumferential speed of a 2nd area | region. Accordingly, since slip does not occur in the second region of the pair of transport rolls, it is possible to suppress liquid seepage from the recording region of the recording medium, and it is possible to suppress transport failure.

The droplet discharge device according to claim 11 is the droplet discharge device according to any one of claims 1 to 10, wherein an axial direction of the second region of at least one roll of the transport roll pair The cross-sectional shape of is made uneven.

In the droplet discharge device according to the eleventh aspect, the cross-sectional shape in the axial direction of the second region of at least one roll of the transport roll pair is uneven. Here, when water-based ink is used or the like, after image recording, the recording medium such as paper causes swelling (partial unevenness) due to swelling. Wrinkles approach. However, in the present invention, since the recording medium is not nipped in the concave portion and the cockle is released into the concave portion, the generation of wrinkles can be suppressed.

  A droplet discharge device according to a twelfth aspect of the present invention is the droplet discharge device according to any one of the first to eleventh aspects, wherein the first of the rolls contacting the recording surface of the recording medium of the pair of transport rolls. Two regions are coated with a water repellent material.

  In the roll contacting the recording surface of the recording medium of the pair of conveying rolls of the droplet discharge device according to claim 12, the second region contacting the recording surface is coated with a water repellent material. Thereby, the offset of the liquid from the recording medium to the roll can be suppressed.

  A droplet discharge device according to a thirteenth aspect of the present invention is the droplet discharge device according to any one of the first to twelfth aspects, wherein the roll contacting the recording surface of the recording medium of the pair of transport rolls is cleaned. A cleaning member is provided.

  In the droplet discharge device according to the thirteenth aspect, paper dust or the like adhering to the roll contacting the recording surface of the recording medium of the pair of transport rolls is cleaned by the cleaning member. Accordingly, it is possible to suppress the liquid offset from the recording medium to the roll due to the foreign matter adhering to the roll.

  Since the present invention has the above-described configuration, it is possible to suppress the offset of the liquid from the recording medium to the roll that occurs when the recording medium after image recording is conveyed by the conveying roll pair, and to improve the conveying performance of the recording medium by the conveying roll pair. it can.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an ink jet recording apparatus 12 of the present embodiment. A paper feed tray 16 is provided in the lower part of the casing 14 of the ink jet recording apparatus 12, and the sheets P stacked in the paper feed tray 16 can be taken out one by one by a pickup roll 18. The taken paper P is transported by a plurality of transport roller pairs 20 constituting a predetermined transport path 22.

  An endless transport belt 28 is stretched around the drive roll 24 and the driven roll 26 above the paper feed tray 16. A recording head array 30 is disposed above the conveyor belt 28 and faces the flat portion 28F of the conveyor belt 28. This opposed area is an ejection area SE where ink droplets are ejected from the recording head array 30. The sheet P transported along the transport path 22 is held by the transport belt 28 and reaches the discharge area SE, and ink droplets corresponding to image information are attached from the recording head array 30 in a state of facing the recording head array 30. The

  In this embodiment, the recording head array 30 has a long shape in which the effective recording area is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), and is yellow (Y) and magenta (M). , Four ink jet recording heads (hereinafter referred to as recording heads) 32 corresponding to the four colors of Sian (C) and Black (K) are arranged along the transport direction, and a full color image can be recorded. ing.

  Each recording head 32 is driven by a head drive circuit (not shown). The head drive circuit has a configuration in which, for example, the ejection timing of ink droplets and the ink ejection port (nozzle) to be used are determined according to image information and a drive signal is sent to the recording head 32.

  The recording head array 30 may be stationary in a direction orthogonal to the transport direction. However, if the recording head array 30 is configured to move as necessary, an image with higher resolution can be obtained by multi-pass image recording. Or the failure of the recording head 32 is not reflected in the recording result.

  Four maintenance units 34 corresponding to the respective recording heads 32 are arranged on both sides of the recording head array 30. As shown in FIG. 2, when performing maintenance on the recording head 32, the recording head array 30 is moved upward, and the maintenance unit 34 moves into the gap formed between the conveyance belt 28 and enters. . Then, a predetermined maintenance operation (suction, wiping, capping, etc.) is performed while facing the nozzle surface.

  As shown in FIG. 3, a charging roll 36 to which a power source 38 is connected is disposed on the upstream side of the recording head array 30. The charging roll 36 is driven while sandwiching the conveyance belt 28 and the paper P with the driven roll 26, and presses the paper P against the conveyance belt 28. At this time, since a predetermined potential difference is generated between the grounded driven roll 26, the sheet P can be charged and electrostatically attracted to the transport belt 28.

  A separation plate 40 is disposed on the downstream side of the recording head array 30 and separates the paper P from the conveyance belt 28. The peeled paper P is conveyed by a plurality of discharge roll pairs 50 that constitute a discharge path 44 on the downstream side of the peeling plate 40, and is discharged to a paper discharge tray 46 provided at the top of the housing 14.

  As shown in FIGS. 1 and 2, an ink tank 35 that stores ink of each color is disposed above the recording head array 30. Each recording head 32 is connected to each ink tank 35.

  Here, the first embodiment of the discharge roll pair 50 will be described.

  As shown in FIGS. 4 and 5, the discharge roll pair 50 includes a drive roll 52 and a driven roll 54 that rotates following the drive roll 52 by the frictional force of the drive roll 52. The driven roll 54 is disposed on the recording surface side of the paper P, and the drive roll 54 is disposed on the back surface side of the recording surface of the paper P. The recording surface referred to here is a surface on which an image is recorded from the recording head array 30 immediately before the paper P is transported to the discharge path 44. After recording the second image of the double-sided printing, the recording surface of the paper P is recorded. An image is also recorded on the back side of the recording surface.

  Here, the region A at both axial ends of the driven roll 54 is formed of the material A, and the region B between the regions A on both sides of the driven roll 54 is formed of the material B. The material A is a rubber or metal having a hardness higher than that of the material B, and the material B is an elastic body such as a rubber having a hardness lower than that of the material A.

  For this reason, the nip force in the region A of the transport roll pair 50 is higher than the nip force in the region B of the transport roll pair 50. The drive roll 52 is entirely made of material C. This material C is a metal, rubber, resin, or the like generally used for a paper transport roll.

  Further, the axial length of the area B of the driven roll 54 is L1, the axial length of the driven roll 54 is L2, and the axial lengths of the areas A on both sides are the same L3 (= (L2-L1) / 2). It has become. Here, the axial length L2 of the driven roll 54 is larger than the width of the paper P (the length in the direction orthogonal to the transport direction) W2, and the axial length L1 of the area B of the driven roll 54 is: It is larger than the width W1 of the recording area P1 of the paper P. Further, the sheet P is conveyed with the center portion in the width direction aligned with the center portion in the axial direction of the discharge roll pair 50.

  Therefore, the non-recording area P2 on the outer side in the width direction of the recording area P1 of the paper P is nipped by the high hardness area A of the driven roll 54 and the drive roll 54, and the recording area P1 of the paper P is Nipped by the low hardness region B 54 and the drive roll 52.

  As a result, the paper P can be conveyed without slipping, the ink seepage from the recording region P1 can be suppressed, and the ink offset from the paper P to the driven roll 54 can be suppressed.

  Further, the surface of the area B of the driven roll 54 is coated with a material having excellent water repellency such as a fluororesin, so that the ink offset from the paper P to the driven roll 54 is suppressed.

  In this embodiment, since the driven roll 54 is driven by the friction force on the drive roll 52, there is no speed difference between the peripheral speed of the drive roll 52 and the peripheral speed of the driven roll 54. For this reason, since slip does not occur in the nip portion of the pair of transport rolls 50, it is possible to suppress the seepage of ink from the paper P, and to suppress poor transport. However, as shown in FIG. 6, the rotation shaft 52A of the drive roll 52 and the rotation shaft 54A of the driven roll 54 are connected via gears 56 and 57, and the rotational force of the drive roll 52 is driven by the gears 56 and 57. By transmitting to 54, the driven roll 54 may be driven. This configuration is effective when the frictional force between the driving roll 52 and the driven roll 54 is small because a constant conveying force can be obtained regardless of the frictional force between the driving roll 52 and the driven roll 54.

  In the present embodiment, the hardness of the region B in the driven roll 54 is lower than the hardness of the region A. However, it is sufficient that the nip force in the region B is lower than the nip pressure in the region A in the discharge roll pair 50. In the roll 52, the hardness of the region B may be lower than the hardness of the region A, and the hardness of the region B may be lower than the hardness of the region A in both the driven roll 54 and the driving roll 52.

  Next, the discharge roll 60 (refer FIG. 7) of 2nd Example of the discharge roll pair 50 is demonstrated. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Example, and description is abbreviate | omitted.

  As shown in FIG. 7, the discharge roll pair 60 includes a drive roll 52 and a driven roll 64 that rotates following the drive roll 52 by frictional force with the drive roll 52. The driven roll 64 is disposed on the recording surface side of the paper P, and the drive roll 64 is disposed on the back surface side of the recording surface of the paper P.

  Here, the diameter φ2 of the region A at both axial ends of the driven roll 64 is larger than the diameter φ1 of the region B between the regions A on both sides of the driven roll 64. For this reason, the nip force in the region A at both axial ends of the transport roll pair 60 is higher than the nip force in the region B of the transport roll pair 60. Thereby, it is possible to obtain a sufficient transport force while suppressing printing disturbance.

  For example, let us consider a case in which the regions A and B are both a rubber material having a hardness of about 40, and the driven roll pressing force is 4N. When printing on a paper having a paper thickness of about 100 μm, if the difference between φ2 and φ1 is 300 μm, the gap in the region B becomes 30 μm to 85 μm due to deformation of the region A and bending of the roll shaft caused by pressing. Thereby, it is possible to obtain a sufficient conveying force without causing printing disturbance.

  The optimum diameter difference varies depending on the material of the roll, the nip pressure, and the paper to be printed, and it is desirable to provide means for changing the diameter difference according to the type of paper or the thickness of the paper. As the diameter difference changing means, the roll diameter changing means described in the fifth embodiment or the sixth embodiment described later can be applied.

  The axial length of the area B of the driven roll 64 is L1, the axial length of the driven roll 64 is L2, and the axial lengths of the areas A on both sides of the driven roll 64 are the same as L3 (= (L1-L2 ) / 2), the axial length L2 of the driven roll 64 is larger than the width W2 of the paper P, and the axial length L1 of the area B of the driven roll 64 is the same as in the first embodiment. Is larger than the width W1 of the recording area P1 of the paper P. Further, the sheet P is transported with the center portion in the width direction aligned with the center portion in the axial direction of the discharge roll pair 60.

  Therefore, the non-recording area P2 on the outer side in the width direction of the recording area P1 of the paper P is nipped by the large-diameter area A of the driven roll 64 and the driving roll 52, and the recording area P1 of the paper P is driven by the driven roll. Nipping is performed by the small-diameter region B of 64 and the driving roll 52.

  Accordingly, the paper P can be transported without slipping, ink can be prevented from seeping out from the paper P, and ink offset from the paper P to the driven roll 54 can be suppressed.

  8A and 8B, the area A and the area B of the driven roll 64 are separate members, and the area A is directly fixed to the rotation shaft 64A of the driven roll 64, and the area B is It is rotatably attached to the rotating shaft 64A via a bearing 66. For this reason, since the area A and the area B of the driven roll 64 are individually driven by the drive roll 52, there is no speed difference between the peripheral speed of the area A and the peripheral speed of the area B. Accordingly, no slip occurs in the region B of the transport roll pair 60, so that ink can be prevented from seeping out from the paper P, and a transport failure can be suppressed. The same effect can be obtained when the area A of the driven roll 64 is attached to the rotating shaft 64A via a bearing and the area B of the driven roll 64 is directly fixed to the rotating shaft 64A.

  In this embodiment, the outer diameter of the area B in the driven roll 54 is smaller than the outer diameter of the area A. However, the nip force in the area B of the discharge roll pair 60 is more than the nip force in the area A of the transport roll pair 60. The outer diameter of the region B in the driving roll 52 may be smaller than the outer diameter of the region A of the driving roll 52, and both the driven roll 54 and the driving roll 52 are outside the region B. The diameter may be smaller than the outer diameter of region A. Further, in addition to making the outer diameter of the region B smaller than the outer diameter of the region A in at least one of the driven roll 54 and the driving roll 52, the hardness of the region B in the at least one of the driven roll 54 and the driving roll 52 is set as the region. It may be lower than the hardness of A. In this case, an even higher effect can be obtained.

  Next, the discharge roll pair 70 (see FIG. 9) of the third embodiment of the discharge roll pair 50 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st, 2nd Example, and description is abbreviate | omitted.

  As shown in FIGS. 9 and 10, the discharge roll pair 70 includes a drive roll 52 and a driven roll 74 that rotates following the drive roll 52 by frictional force with the drive roll 52. The driven roll 74 is disposed on the recording surface side of the paper P, and the driving roll 52 is disposed on the back surface side of the recording surface of the paper P.

  As in the first embodiment, the region A at both axial ends of the driven roll 74 is formed of the material A, and the region B between the regions A on both sides of the driven roll 74 is formed of the material B. The material A is a rubber or metal having a hardness higher than that of the material B, and the material B is an elastic body such as a rubber having a hardness lower than that of the material A.

  For this reason, the nip force in the region A at both axial ends of the transport roll pair 70 is higher than the nip force in the region B between the regions A of the transport roll pair 70.

Further, the area B of the driven roll 74 is divided into a plurality (for example, four as shown in the figure) of areas B0, and the areas B0 are arranged at intervals in the axial direction. That is, the cross-sectional shape in the axial direction of the region B of the driven roll 74 is uneven.

  Here, when water-based ink is used, after printing, the paper P is swollen due to swelling, and when the paper is large, the paper P is wrinkled when the paper P is nipped. However, in this embodiment, the paper P is not nipped between the areas B0, and the cockle is released at this position, so that generation of wrinkles can be suppressed.

  In the present embodiment, the material of the region A and the region B of the driven roll 74 is different as in the first embodiment, but the region A and the region B of the driven roll 74 are different from those in the second embodiment. You may vary the diameter.

  Next, a discharge roll pair 80 (see FIG. 11) which is a fourth embodiment of the discharge roll pair 50 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to the 1st thru | or 3rd Example, and description is abbreviate | omitted.

  As shown in FIGS. 11A to 11C and FIG. 12, the discharge roll pair 80 is driven and rotated by the drive roll 52 and the driven rolls 83 and 84 that are driven by the friction force between the drive roll 52 and the drive roll 52. , 85. The driven rolls 83, 84, and 85 are disposed on the recording surface side of the paper P, and the drive roll 52 is disposed on the back surface side of the recording surface of the paper P.

  The driven rolls 83, 84, and 85 are rotatably supported on the same frame 86. The frame 86 is rotatable around a rotation axis 86A substantially parallel to the axial direction of the drive roll 52, supports the driven rolls 83, 84, and 85 around the rotation axis 86A, and rotates to follow the driven roll. 83, 84, and 85 are sequentially brought into contact with the drive roll 52.

  Similarly to the first embodiment, the regions A at both axial ends of the driven rolls 83, 84, and 85 are made of the material A, and the regions B between the regions A on both sides of the driven rolls 83, 84, and 85 are made of the material. B is formed. The material A is a rubber or metal having a hardness higher than that of the material B, and the material B is an elastic body such as a rubber having a hardness lower than that of the material A.

Here, the axial length L _A 1 of the area B of the driven roll 83, the axial length L _B 1 of the area B of the driven roll 84, and the axial length L _C 1 of the area B of the driven roll 84. The relationship is L _A 1 <L _B 1 <L _C 1. Further, the axial length L _A 2 of the driven roll 83, the axial length L _B 2 of the driven roller 84, relationship between the length L _C 2 in the axial direction of the driven roll 85, L _A 2 <L _B 2 <L _C 2 is satisfied.

Further, the axial length L _A 2 of the driven roll 83 is wider than the width W _A 2 of the small size (for example, postcard size) paper P, and the axial length L _A of the area B of the driven roll 83 is larger. 1 is wider than the width W _A 1 of the recording area P _A 1 of the small-sized paper P and narrower than the width W _A 2 of the small-sized paper P. Further, the small-size paper P is conveyed with the center portion in the width direction aligned with the center portion in the axial direction of the driven roll 83.

For this reason, the non-recording area P _A 2 on the outer side in the width direction of the recording area P _A 1 of the small size paper P is nipped by the high hardness area A of the driven roll 83 and the driving roll 52, and the small size of the recording area P _A 1 The recording area P _A 1 of the paper P is nipped by the low hardness area B of the driven roll 83 and the driving roll 52.

The axial length L _B 2 of the driven roll 84 is wider than the width W _B 2 of the medium-sized (for example, A4 landscape) paper P, and the axial length L _B of the area B of the driven roll 84 is. 1 is wider than the width W _B 1 of the recording area P _B 1 of the medium-size paper P and narrower than the width W _B 2 of the medium-size paper P. Further, the medium-sized paper P is transported with the central portion in the width direction aligned with the central portion in the axial direction of the driven roll 84.

Therefore, the non-recording area P _B 2 on the outer side in the width direction of the recording area P _B 1 of the medium-sized paper P is nipped by the high-hardness area A of the driven roll 84 and the driving roll 52, The recording area P _B 1 of the paper P is nipped by the low-hardness area B of the driven roll 84 and the drive roll 52.

Furthermore, the axial length L _{C2 of} the driven roll 85 is wider than the width W _C2 of the large-size (for example, A4 vertical, A3 horizontal) paper P, and the axial length of the area B of the driven roll 85 is long. The length L _C 1 is wider than the width W _C 1 of the recording area P _C 1 of the large size paper P and narrower than the width W _C 2 of the large size paper P. Further, the large-size paper P is conveyed with its widthwise center portion aligned with the axial center portion of the driven roll 85.

Therefore, the non-recording area P _C 2 on the outer side in the width direction of the recording area P _C 1 of the large size paper P is nipped by the high hardness area A of the driven roll 85 and the driving roll 52, and the large size paper P The recording area P _C 1 of the sheet P is nipped by the low hardness area B of the driven roll 85 and the drive roll 52.

  That is, in the present embodiment, the same effects as those of the first embodiment can be exerted on the paper P having a plurality of types of sizes assumed in advance. In addition, by replacing the driven rolls 83, 84, 85 with the same configuration as the driven rolls 64, 74 of the second and third embodiments, the second, The same effect as in the third embodiment can be exhibited.

  Next, the discharge roll pair 90 (see FIG. 13) of the fifth embodiment of the discharge roll pair 50 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st thru | or 4th embodiment, and description is abbreviate | omitted.

  As shown in FIG. 13, the discharge roll pair 90 includes a drive roll 52 and a driven roll 94 that rotates following the drive roll 52 by the frictional force with the drive roll 52. The driven roll 94 is disposed on the recording surface side of the paper P, and the drive roll 52 is disposed on the back surface side of the recording surface of the paper P.

  The area B of the driven roll 94 is divided into four areas B1, B2, B3, and B4, and the areas B1, B2, B3, and B4 are arranged at intervals in the axial direction. In addition, four regions A1, A2, A3, and A4 are arranged at intervals in the axial direction.

Paper P of various sizes, which are conveyed aligned with the widthwise end side, the driven roller 94, the region B1 is provided facing the recording area P _A 1 of the paper P of small size, the small-sized paper P non-recording area P _a 2 regions A1, A2 facing is provided in the region B1 facing the recording area P _B 1 of medium-sized sheets P, A2, B2 are provided, the medium-size sheet P non-recording area P _B 2 regions A1, A3 facing is provided, also, the region B1, A2, B2, A3, B3, B4 facing the recording area P _C 1 of the paper P of a large size provided the Thus, areas A1 and A4 are provided facing the non-recording area P _C2 of the large size paper P.

  The diameters of the regions B1, B2, B3, and B4 are φ1, and the diameters of the regions A1 and A4 are φ2 that is larger than φ1.

  Here, as shown in FIG. 14, the roll portions 96 in the regions A <b> 2 and A <b> 3 are attached to the rotation shaft 94 </ b> A of the driven roll 94 via the wheel 98 and the bearing 102. The bearing 102 is attached to the rotating shaft 94 </ b> A, and the wheel 98 is fitted between the bearing 102 and the roll portion 96.

  The wheel 98 includes a cylindrical inner wheel 98A fixed to the outer periphery of the bearing 102, a cylindrical outer wheel 98B fixed to the rotating shaft 94A and fitted to the inner periphery of the roll portion 96, and an inner wheel 98A. A plurality of spacers 98C provided between the outer wheel 98B and the outer wheel 98B. The outer wheel 98B is formed with slits S at a predetermined pitch in the circumferential direction, and one end of the spacer 98C is inserted into the slit S, and the other end is fixed to the outer periphery of the inner wheel 98A.

  As shown in FIG. 15, the rotating shaft 94 </ b> A has a cylindrical shape, and the shaft 104 is rotatably fitted in the rotating shaft 94. Further, a key groove (not shown) is formed near the area A3 of the inner wheel 98A in the area A2, a hole H is formed in the rotating shaft 94A so as to face the key groove, and a hole H is formed in the shaft 104. A key 106 that protrudes from the key groove and can be fitted into the key groove is provided.

  A key groove (not shown) is formed near the area A2 of the inner wheel 98A in the area A3. A hole H is formed in the rotary shaft 94A so as to face the key groove, and a hole H is formed in the shaft 104. A key 106 that protrudes from the key groove and can be fitted into the key groove is provided.

  Further, a drive unit (not shown) such as a stepping motor for rotating the shaft 104 and a drive unit (not shown) such as a stepping motor for moving the shaft 104 in the axial direction are provided.

  As shown in FIG. 15A, when the shaft 104 is moved to the region A2 side as much as possible, the key 106 on the region A2 side and the key groove of the inner wheel 98A on the region A2 are fitted, and the key on the region A3 side is fitted. 106 is disengaged from the keyway of the inner wheel 98A in the region A3. In this state, as shown in FIG. 14B, when the shaft 104 is rotated in the counterclockwise direction in the drawing, the inner wheel 98A is rotated in the counterclockwise direction in the drawing in the region A2, and the spacer 98C is moved outside. It is inserted between the wheel 98B and the roll part 96. As a result, in the region A2, the diameter of the roll portion 96 is increased by the thickness of the spacer 98C to become φ2. Further, when the shaft 104 is rotated in the clockwise direction in the drawing from this state, the inner wheel 98A is rotated in the clockwise direction in the drawing in the region A2, and the spacer 98C is interposed between the outer wheel 98B and the roll portion 96. Come off. As a result, as shown in FIG. 14A, in the region A2, the diameter of the roll portion 96 is reduced by the thickness of the spacer 98C to become φ1.

  On the other hand, in the region A3, since the inner wheel 98A is not rotated, the diameter of the roll portion 96 does not change.

  Further, as shown in FIG. 15B, when the shaft 104 is moved to the center of the movable range in the axial direction, the key 106 on the area A2 side and the key groove of the inner wheel 98A on the area A2 are disengaged. The key 106 on the region A3 side and the key groove of the inner wheel 98A on the region A3 are disengaged. In this state, even if the shaft 104 is rotated, the inner wheel 98A is not rotated in the regions A2 and A3, and the diameter of the roll portion 96 does not change.

  As shown in FIG. 15C, when the shaft 104 is moved to the area A3 side as much as possible, the key 106 on the area A3 side and the key groove of the inner wheel 98A on the area A3 are fitted, and the area A2 side The key 106 and the key groove of the inner wheel 98A in the region A2 are disengaged. In this state, as shown in FIG. 14B, when the shaft 104 is rotated in the counterclockwise direction in the drawing, the inner wheel 98A is rotated in the counterclockwise direction in the drawing in the region A3, and the spacer 98C is It is inserted between the wheel 98B and the roll part 96. Thereby, in the region A3, the diameter of the roll portion 96 is increased by the thickness of the spacer 98C to become φ2. Further, when the shaft 104 is rotated in the clockwise direction in the drawing from this state, the inner wheel 98A is rotated in the clockwise direction in the drawing in the region A3, and the spacer 98C is interposed between the outer wheel 98B and the roll portion 96. Come off. As a result, as shown in FIG. 14A, in the region A2, the diameter of the roll portion 96 is reduced by the thickness of the spacer 98C to become φ1.

  On the other hand, in the region A2, since the inner wheel 98A is not rotated, the diameter of the roll portion 96 does not change.

  That is, the diameters of the areas A2 and A3 are variable between a diameter φ2 equivalent to the diameters of the areas A1 and A4 and a diameter φ1 equivalent to the diameters of the areas B1, B2, B3, and B4, and are conveyed. It changes according to the size of the paper P.

Specifically, when a small-size sheet P is conveyed, the diameter of the area A2 is φ2, and the diameter of the area A3 is φ1. As a result, the non-recording area P _A 2 on the outer side in the width direction of the recording area P _A 1 of the small-sized paper P is nipped by the large-diameter areas _A 1 and _A 2 of the driven roll 94 and the driving roll 52, The recording area P _A 1 of the size paper P is nipped by the small diameter area B 1 of the driven roll 94 and the drive roll 52.

Further, when the medium-sized paper P is conveyed, the diameter of the area A3 is φ2, and the diameter of the area A2 is φ1. As a result, the non-recording area P _B 2 on the outer side in the width direction of the recording area P _B 1 of the medium-sized paper P is nipped by the large-diameter areas A 1 and A 3 of the driven roll 94 and the drive roll 52, The recording area P _B 1 of the size paper P is nipped by the small diameter areas B 1, A 2, B 2 of the driven roll 94 and the drive roll 52.

Further, when the large-size paper P is conveyed, the diameter of the area A2 is φ1, and the diameter of the area A3 is φ1. As a result, the non-recording area P _C 2 on the outer side in the width direction of the recording area P _C 1 of the large size paper P is nipped by the large diameter areas A 1 and A 4 of the driven roll 94 and the driving roll 52, The recording area P _C 1 of the size paper P is nipped by the small diameter areas B 1, A 2, B 2, A 3, B 3, B 4 of the driven roll 94 and the drive roll 52.

  As a result, in the present embodiment, the same effects as in the second embodiment can be exerted on paper P having a plurality of types of sizes assumed in advance.

  Next, the discharge roll pair 110 (see FIG. 16) of the sixth embodiment of the discharge roll pair 50 will be described. In addition, the same code | symbol is attached | subjected to the structure similar to 1st thru | or 5th embodiment, and description is abbreviate | omitted.

  As shown in FIG. 16, the discharge roll pair 110 includes a drive roll 52 and a driven roll 114 that rotates following the drive roll 52 by the frictional force of the drive roll 52. The driven roll 114 is disposed on the recording surface side of the paper P, and the driving roll 52 is disposed on the back surface side of the recording surface of the paper P.

As in the fifth embodiment, the area B of the driven roll 114 is divided into four areas B1, B2, B3, and B4, and the areas B1, B2, B3, and B4 are arranged at intervals in the axial direction. Has been. In addition, four regions A1, A2, A3, and A4 are arranged at intervals in the axial direction. In addition, each of the areas A1, A2, A3, A4, B1, B2, B3, and B4 is similar to the fifth embodiment in that the small, medium, and large size recording areas P _A 1, P _B 1, P _C 1, non- It is provided corresponding to the recording areas P _A 2, P _B 2 and P _C 2.

  The diameters of the regions B1, B2, B3, and B4 are φ1, and the diameters of the regions A1 and A4 are φ2 that is larger than φ1.

  Here, as shown in FIG. 17, the areas A2 and A3 include a first roll part 116A joined to the rotating shaft 114A of the driven roll 114 and a second roll part 116B joined to the outside of the first roll part 116A. The variable length flexible alloy flexible wire (see Japanese Patent Application Laid-Open No. 2004-197572, hereinafter referred to as the flexible wire) 116C wound around the second roll portion 116B, the flexible wire 116C and the second roll portion 116B. And a third roll portion 116D joined to the outside of the first roll portion.

  As shown in FIG. 17A, the first roll portion 116A is formed of rubber, resin, or the like, and is joined to the rotating shaft 114A by adhesion, heat welding, or the like. Further, as shown in FIG. 17B, the second roll part 116B is formed of a material having a hardness lower than that of the first roll part 116A, such as rubber or foamed urethane, and is easily deformed. 1 roll part 116A is joined.

  The flexible thin wire 116C is composed of a plurality of end-like ring-shaped thin wires arranged in the axial direction. Each thin wire is a shape memory alloy that changes its length when energized. In addition, you may comprise this flexible thin wire | line 116C with one spiral thin wire | line.

  Further, one end of the flexible thin wire 116C is grounded to the rotating shaft 114A, and the other end of the flexible thin wire 116C in the regions A2 and A3 is provided with an insulating coating such as vinyl extending from one axial end portion of the rotating shaft 114A. The lead wires 118 and 119 are connected. Electrodes 120 and 121 insulated from the rotating shaft 114A are provided at one axial end portion of the rotating shaft 114A, and lead wires 118 and 119 are connected to the electrodes 120 and 121, respectively. In addition, a power source 122 is connected to the electrodes 120 and 121, and switches 124 and 125 are provided on the wiring between the electrode 120 and the power source 122 and the wiring between the electrode 121 and the power source 122, respectively.

  Further, as shown in FIG. 17C, the third roll portion 116D is formed of a material having a lower hardness and easier to deform than the first roll portion 116A, such as rubber or foamed urethane, and the third roll portion 116D is bonded or thermally welded. The two roll portions 116B and the flexible thin wires 116C are joined.

  Here, as shown in FIG. 18B, when the flexible thin wire 116C is energized, it contracts to reduce its diameter. As a result, the diameters of the second roll portion 116B and the third roll portion 116D are reduced to φ1 or less. Further, as shown in FIG. 18A, the flexible thin wire 116C is restored and expanded in diameter when energization is released. As a result, the diameters of the second roll part 116B and the third roll part 116D are enlarged to be equal to φ2.

  That is, the diameters of the areas A2 and A3 are variable between a diameter φ2 equivalent to the diameters of the areas A1 and A4 and a diameter φ1 equal to or less than the diameters of the areas B1, B2, B3, and B4. It is changed according to the size of P.

Specifically, when transporting the small-size paper P, the switch 124 is turned off, the switch 125 is turned on, the diameter of the area A2 is φ2, and the diameter of the area A3 is φ1. As a result, the non-recording area P _A 2 on the outer side in the width direction of the recording area P _A 1 of the small-sized paper P is nipped by the large-diameter areas _A 1 and _A 2 of the driven roll 94 and the driving roll 52, The recording area P _A 1 of the size paper P is nipped by the small diameter area B 1 of the driven roll 94 and the drive roll 52. By turning on the switch 125, the nip pressure between the region A3 and the driving roll 52 can be reduced and the wear between the region A3 and the driving roll 52 can be reduced. However, it is not essential to turn on the switch 125. .

Further, when the medium-sized paper P is conveyed, the switch 124 is turned on, the switch 125 is turned off, the diameter of the area A3 is φ2, and the diameter of the area A2 is φ1. As a result, the non-recording area P _B 2 on the outer side in the width direction of the recording area P _B 1 of the medium-sized paper P is nipped by the large-diameter areas A 1 and A 3 of the driven roll 94 and the drive roll 52, The recording area P _B 1 of the size paper P is nipped by the small diameter areas B 1, A 2, B 2 of the driven roll 94 and the drive roll 52.

Further, when the large-size paper P is conveyed, the switches 124 and 125 are turned on, and the diameters of the areas A2 and A3 are set to φ1. As a result, the non-recording area P _C 2 on the outer side in the width direction of the recording area P _C 1 of the large size paper P is nipped by the large diameter areas A 1 and A 4 of the driven roll 94 and the driving roll 52, The recording area P _C 1 of the size paper P is nipped by the small diameter areas B 1, A 2, B 2, A 3, B 3, B 4 of the driven roll 94 and the drive roll 52.

  As a result, in the present embodiment, the same effects as those of the second and fifth embodiments can be exerted on paper P having a plurality of types of sizes assumed in advance.

  In the present embodiment, the reason why the first roll portion 116A is provided is that there is a concern that only the low-hardness second roll portion 116B increases the shearing deformation in the circumferential direction and adversely affects the conveyance characteristics. is there. However, when the shear deformation of the second roll part 116B is sufficiently small, the second roll part 116B may be provided directly on the rotating shaft 114A without providing the first roll part 116A.

  Next, a modification of the embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  As shown in FIG. 19A, in the present embodiment, a cleaning blade 120 that contacts the driven roll 52 of the discharge roll pair 50 is provided. The cleaning blade 120 is made of resin or the like and scrapes off paper dust and ink adhering to the driven roll 52. Thereby, it is possible to suppress the ink offset from being induced by the foreign matter adhering to the driven roll 52.

  As a mechanism for cleaning the driven roll 54, as shown in FIG. 19B, a cleaning roll 122 for sucking foreign matter adhering to the driven roll 54 or a driven roll 54 as shown in FIG. 19C. Other mechanisms such as a cleaning web 124 that scrapes and sucks foreign matter adhering to the surface can also be applied.

  In the present embodiment, the present invention has been described by taking an inkjet recording apparatus as an example. However, the present invention is not limited to an inkjet recording apparatus, and the present invention is not limited to an inkjet recording apparatus, and is a color filter for a display that is performed by discharging colored ink onto a polymer film. The present invention can be applied to a general liquid droplet ejection apparatus for various industrial uses, such as production of an EL display panel formed by discharging an organic EL solution onto a substrate.

  In addition, the “recording medium” that is a target of image recording in the droplet discharge device of the present invention includes a wide range of objects as long as the droplet discharge head discharges droplets. Accordingly, the recording medium includes recording paper, an OHP sheet, and the like, but also includes, for example, a polymer film.

  Furthermore, in the present embodiment, the present invention has been described by taking as an example a configuration in which a plurality of inkjet recording heads that are shorter than the width of the paper P are arranged in the width direction of the paper P, but the present invention is not limited thereto. For example, the present invention can be applied to a configuration in which an inkjet recording head that is shorter than the width of the paper P is moved in the width direction of the paper P.

1 is a side view illustrating an outline of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a side view illustrating an outline of an ink jet recording apparatus according to an embodiment of the present invention. It is a side view which shows the outline of the printing part of the inkjet recording device of embodiment of this invention. It is the schematic which shows the 1st Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. FIG. 4 is a perspective view illustrating a first example of a discharge roll pair provided in the ink jet recording apparatus according to the embodiment of the present invention. It is a perspective view which shows the modification of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. It is the schematic which shows the 2nd Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. (A) is 8 (A) -8 (A) sectional drawing of FIG. 8, (B) is 8 (B) -8 (B) sectional drawing of FIG. It is the schematic which shows the 3rd Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. It is a perspective view which shows the 3rd Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. (A)-(C) are schematic which shows the 4th Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. It is a perspective view which shows the 4th Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. It is the schematic which shows the 5th Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. (A), (B) is 14-14 sectional drawing of FIG. It is 15-15 sectional drawing of FIG. It is the schematic which shows the 6th Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. (A)-(C) are perspective views which show the 4th Example of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped. (A), (B) is 18-18 sectional drawing of FIG. (A)-(C) are sectional drawings which show the modification of the discharge roll pair with which the inkjet recording device of embodiment of this invention was equipped.

Explanation of symbols

12 Inkjet recording device (droplet ejection device)
28 Conveying belt (conveying means)
32 Inkjet recording head (droplet ejection head)
50 discharge roll pair (conveying roll pair)
52 Drive roll (roll)
54 Followed roll
60 discharge roll pair (conveying roll pair)
64 Followed roll (roll)
70 discharge roll pair (conveying roll pair)
74 Followed roll (roll)
80 discharge roll pair (conveying roll pair)
84 Followed roll (roll)
90 discharge roll pair (conveying roll pair)
94 Followed Roll (Roll)
110 Discharge roll pair (conveying roll pair)
114 Followed roll (roll)
120 Cleaning blade (cleaning member)
122 Cleaning roll (cleaning member)
124 Cleaning web (cleaning member)
A area (first area)
A1 to A4 area (first area)
B area (second area)
B0 to B4 region (second region)
P paper (recording medium)
P1 recording area P2 non-recording area

Claims (13)

A droplet discharge head for discharging droplets;
Conveying means for conveying a recording medium to face the droplet discharge head;
A pair of transport rolls for transporting a recording medium downstream in the transport direction of the transport means;
A droplet discharge device comprising:
A first region of the pair of conveying rolls that nips a non-recording region at both ends in the width direction of the recording medium;
A second region of the pair of transporting rolls that nips a recording region inside the width direction of the non-recording region of the recording medium,
The pair of transport rolls includes a drive roll that is rotationally driven, and a driven roll that is driven in pressure contact with the drive roll,
The driven roll portion of the driven roll in the first region is fixed to the rotating shaft of the driven roll, and the driven roll portion of the driven roll in the second region is rotatably attached to the rotating shaft,
The droplet discharge device according to claim 1, wherein a nip force in the second region of the transport roll pair is lower than a nip force in the first region of the transport roll pair.   2. The droplet discharge device according to claim 1, wherein the hardness of the at least one roll of the transport roll pair in the second region is lower than the hardness of the roll in the first region.   The material of the second region of the roll is rubber, and the material of the first region of the roll is rubber or metal having higher hardness than the material of the second region of the roll. The liquid droplet ejection apparatus described.   4. The liquid droplet ejection apparatus according to claim 2, wherein the position of the first area of the roll can be changed according to the size of the recording medium.   The liquid droplet ejection apparatus according to claim 4, wherein the roll is provided for each size of the recording medium, and is changed according to the size of the recording medium.   The outer diameter in the said 2nd area | region of the at least one roll of the said conveyance roll pair was made smaller than the outer diameter in the said 1st area | region of the said roll, The Claim 1 characterized by the above-mentioned. Droplet discharge device.   The liquid droplet ejection apparatus according to claim 6, wherein the position of the first region of the roll can be changed according to the size of the recording medium.   The liquid droplet ejection apparatus according to claim 7, wherein the roll is provided for each size of the recording medium, and is changed according to the size of the recording medium. One roll is provided with the first area for each size of the recording medium, and the outer diameter of the first area between the first areas on both sides of the roll is less than or equal to the outer diameter of the second area of the roll. Can be reduced,
The liquid droplet ejection apparatus according to claim 7, wherein the outer diameter of the first area of the roll facing the recording surface of the recording medium is reduced to be equal to or smaller than the outer diameter of the second area.   10. The droplet discharge device according to claim 6, wherein the first region and the second region of the roll are individually rotatable. 11. The droplet discharge device according to claim 1, wherein an axial cross-sectional shape of the second region of at least one roll of the transport roll pair is uneven.   12. The droplet discharge device according to claim 1, wherein the second region of the roll contacting the recording surface of the recording medium of the transport roll pair is coated with a water repellent material.   The liquid droplet ejection apparatus according to claim 1, further comprising a cleaning member that cleans a roll that contacts a recording surface of the recording medium of the pair of conveying rolls.

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