JP2013075448A - Inkjet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small and compact inkjet recording device, preventing contamination of a conveying means due to undried ink and generation of an offset, and capable of also preventing a color shift due to a change in conveyance speed of a recording medium.SOLUTION: A printer 100 includes a first belt conveying part 20 and a recording part 30 disposed opposite the first belt conveying part 20. A second belt conveying part 40 is disposed at a downstream side of the first belt conveying part 20 with respect to a sheet conveying direction. A sheet P on which an ink image is recorded by the recording part 30 is sent to the second belt conveying part 40, and ink ejected on the surface of the sheet P is dried while passing through the second belt conveying part 40. The second belt conveying part 40 is arranged so that an angle θ formed by a conveying surface 21a of a first conveying belt 21 and a conveying surface 41a of a second conveying belt 41 is an obtuse angle.

Description

  The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink onto a recording medium such as paper in a recording apparatus such as a facsimile, a copying machine, and a printer, and particularly includes a line head type recording head. The present invention relates to an ink jet recording apparatus.

  Recording devices such as facsimiles, copiers, and printers are configured to record images on recording media such as paper, cloth, and OHP sheets. However, depending on the recording method, inkjet, wire dot, thermal It can be classified into formulas and the like. The ink jet recording method can be further classified into a serial type in which recording is performed while the recording head scans the recording medium, and a line head type in which recording is performed by a recording head fixed to the apparatus main body.

  A line head type ink jet recording apparatus is provided with a line head type ink jet head (recording head) for each color in which discharge nozzles are arranged at predetermined intervals over the entire width of a printing area perpendicular to the conveyance direction of the recording medium. ing. The entire recording medium can be printed by discharging ink from the discharge nozzle corresponding to the printing position in accordance with the conveyance of the recording medium.

  Here, the line head type ink jet recording apparatus as described above is capable of high-speed recording as compared with a serial type ink jet recording apparatus in which the recording head scans in the width direction of the recording medium. However, the drying time of the ink ejected on the recording medium is also shortened. Therefore, when a roller or roller is used as a transport means for transporting the recording medium immediately after printing by the recording head, undried ink adheres to the roller or roller, or the adhered ink is retransferred to the recording medium and offset. There was a risk of causing.

  In order to solve the above problems, a method of conveying the recording medium after ink jet printing using a conveying belt that adsorbs and conveys the recording medium to the belt surface is conceivable. Here, if the conveyance belt in the printing area facing the recording head is extended toward the downstream side of the printing area, the circumference of the conveyance belt increases, and the belt conveyance section becomes larger, leading to an increase in cost. . In addition, since the belt retracting area for processing the jammed recording medium in the printing area becomes large, it is an obstacle to miniaturization and space saving of the ink jet recording apparatus.

  Thus, for example, Patent Documents 1 and 2 disclose an inkjet recording apparatus in which a recording medium conveyance path is configured by using a belt conveyance unit that is divided into a conveyance belt in a printing area and a conveyance belt on the downstream side of the printing area. ing. Further, Patent Document 3 discloses a recording medium conveyance mechanism in which a plurality of conveyance belt mechanisms are arranged in the conveyance direction of the recording medium, and the downstream conveyance belt is inclined upward with respect to the upstream conveyance belt. .

JP 2010-52888 A JP 2010-228845 A JP 2005-89076 A

  In the ink jet recording apparatuses described in Patent Documents 1 and 2, the recording medium is transported by two transport belts, so that it is possible to reduce the size of the apparatus while suppressing contamination and offset due to undried ink. However, when a speed difference occurs between the linear speeds of the respective conveying belts, the recording medium conveying speed changes when the recording medium is transferred between the conveying belts, and color misregistration occurs on the upstream side of the recording medium. There was a fear.

  Specifically, when two conveying belts are arranged side by side, if the downstream conveying belt has a high linear velocity, a force for pulling the recording medium is generated, and if the downstream conveying belt has a low linear velocity, the recording medium is conveyed. A force that hinders is generated. At this time, there is no problem as long as the recording medium is firmly held by the upstream conveyance belt, but since the portion held by the upstream conveyance belt is relatively reduced by the conveyance of the recording medium, the recording medium The holding power of the medium gradually decreases. As a result, the recording medium is deviated from the upstream conveying belt, and color misregistration occurs in the print area.

  Further, the configuration of Patent Document 3 stabilizes the behavior of the recording medium even when the leading edge of the recording medium is lifted by making the downstream conveyor belt ascending, so that air enters the lower surface of the recording medium and the leading edge of the recording medium is lifted. The object is to prevent skewing, jamming, image defects, and the like of the recording medium. For this reason, the above-described problem and solution means for suppressing the change in the conveyance speed of the recording medium when the recording medium is transferred between the conveyance belts are not described, and there is no such suggestion. Further, in the configuration of Patent Document 3, a recording head (printing unit) is also opposed to the downstream conveyance belt. That is, Patent Document 3 aims to stabilize the conveyance state of the recording medium during the printing operation in the upstream and downstream recording units, and the conveyance speed of the recording medium transferred to the downstream conveyance belt. The purpose is not to suppress the change and prevent the occurrence of color misregistration in the upstream recording portion.

  SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a compact and compact ink jet recording apparatus capable of preventing contamination of transport means due to undried ink and occurrence of offset, and preventing color misregistration due to changes in the transport speed of a recording medium. The purpose is to provide.

  In order to achieve the above object, the present invention provides an endless first transport belt for sucking and holding a recording medium, a first drive roller for rotationally driving the first transport belt, and the first drive roller. A first belt conveyance unit having a first driven roller that rotatably supports the first conveyance belt, and a recording medium that is disposed to face the first belt conveyance unit and is conveyed by the first conveyance belt And a recording unit having a line head type recording head for discharging ink to the recording medium, and disposed adjacent to the downstream side of the first belt conveyance unit with respect to the conveyance direction of the recording medium. A second endless conveyor belt, a second drive roller that rotationally drives the second conveyor belt, and a second driven roller that rotatably supports the second conveyor belt together with the second drive roller. 2 Comprising a preparative conveying section, and a conveying surface of the first conveyor belt, the angle between the conveying surface of the second conveyor belt is an ink jet recording apparatus is an obtuse angle.

  According to the present invention, in the ink jet recording apparatus configured as described above, a surface obtained by extending the transport surface of the first transport belt in the transport direction of the recording medium intersects the transport surface of the second transport belt.

  According to the present invention, in the ink jet recording apparatus configured as described above, the first drive roller and the second drive roller are connected to the same drive input gear.

  In the ink jet recording apparatus having the above-described configuration, the angle formed by the conveyance surface of the first conveyance belt and the conveyance surface of the second conveyance belt is 140 ° or more and 170 ° or less.

  In the inkjet recording apparatus having the above-described configuration, the present invention satisfies S1 ≧ S2 when the recording medium conveyance speed by the first conveyance belt is S1 and the recording medium conveyance speed by the second conveyance belt is S2. It is characterized by.

  According to the present invention, in the ink jet recording apparatus configured as described above, the suction force per unit area of the recording medium with respect to the first transport belt is F1, and the suction force per unit area of the recording medium with respect to the second transport belt is F2. In this case, F1 ≧ F2 is satisfied.

  According to the present invention, in the ink jet recording apparatus configured as described above, a width direction dimension of the first transport belt is wider than a maximum print width of the recording unit.

  According to the present invention, in the ink jet recording apparatus having the above-described configuration, the ink jet recording apparatus includes a drying device that dries the ink on the recording medium that is suction-held on the transport surface of the second transport belt.

  According to the first configuration of the present invention, by disposing the second belt conveyance unit on the downstream side of the first belt conveyance unit disposed to face the recording unit, the ink is dried during conveyance by the second belt conveyance unit. Time can be secured, and adhesion of undried ink to a conveyance path, a conveyance roller pair, and the like on the downstream side of the second belt conveyance unit can be prevented. At this time, by setting the angle formed by the conveyance surface of the first conveyance belt and the conveyance surface of the second conveyance belt to be an obtuse angle, the conveyance speed of the recording medium transferred from the first belt conveyance unit to the second belt conveyance unit can be reduced. It is possible to effectively prevent the color misregistration in the recording portion by absorbing the fluctuation.

  According to the second configuration of the present invention, in the ink jet recording apparatus having the first configuration, a surface obtained by extending the transport surface of the first transport belt in the transport direction of the recording medium is the transport surface of the second transport belt. Since the leading end of the recording medium is reliably sucked and held on the conveying surface of the second conveying belt, the recording medium is smoothly transferred from the first conveying belt to the second conveying belt. be able to. In addition, since the space is formed below the conveyance surface of the first conveyance belt, it is possible to easily form the deflection that absorbs the variation in the conveyance speed in the recording medium.

  According to the third configuration of the present invention, in the ink jet recording apparatus having the first or second configuration, by connecting the first drive roller and the second drive roller to the same drive input gear, The transport speed of the first transport belt and the transport speed of the second transport belt can be easily set to substantially constant speed, and the substantially constant speed state can be easily maintained. Further, by adjusting the diameter ratio of the first driving roller and the second driving roller, or the gear ratio of the gear fixed to the first driving roller and the second driving roller, the first conveying belt and the second conveying belt are conveyed. The speed can be set to a desired speed, and the set speed can be easily maintained. Furthermore, since the first driving roller and the second driving roller can be driven using one motor, it is advantageous in terms of cost.

  According to the fourth configuration of the invention, in the ink jet recording apparatus having any one of the first to third configurations, an angle formed by the transport surface of the first transport belt and the transport surface of the second transport belt. 140 ° or more and 170 ° or less, the impact transmitted to the recording medium when the recording medium is transferred from the first conveying belt to the second conveying belt is reduced, and the boundary portion between the first conveying belt and the second conveying belt is reduced. In this case, the recording medium can be sufficiently bent.

  According to the fifth aspect of the invention, in the ink jet recording apparatus having any one of the first to fourth aspects, the recording medium conveying speed S1 by the first conveying belt and the recording medium by the second conveying belt are used. When the transport speed S2 of the second roller satisfies S1 ≧ S2, the pulling force by the second belt transport unit does not act on the recording medium when the recording medium is transferred from the first transport belt to the second transport belt. It is possible to prevent the displacement of the recording medium in the transport unit more reliably. Further, the initial deflection can be reliably formed in the bent portion of the recording medium.

  According to the sixth configuration of the present invention, in the ink jet recording apparatus having any one of the first to fifth configurations, the suction force F1 per unit area of the recording medium with respect to the first transport belt and the second transport Even if a large conveyance speed difference that cannot be absorbed due to the deflection of the recording medium occurs due to the fact that the adsorption force F2 per unit area of the recording medium with respect to the belt satisfies F1 ≧ F2, the deviation of the recording medium is a result of the adsorption force. It occurs in the weak second belt conveyance unit. Accordingly, it is possible to more reliably prevent the recording medium from being shifted in the first belt conveyance unit.

  According to the seventh configuration of the invention, in the ink jet recording apparatus having any one of the first to sixth configurations, the width direction dimension of the first transport belt is made wider than the maximum print width of the recording unit. Thus, the recording medium adsorbed on the conveyance surfaces of the first conveyance belt and the second conveyance belt can be maintained in a flat state, and stable printing can be performed in the recording unit.

  According to the eighth configuration of the invention, in the ink jet recording apparatus having any one of the first to seventh configurations, the ink on the recording medium sucked and held on the transport surface of the second transport belt is dried. By providing the drying device, the ink on the recording medium can be dried in a shorter time, and the downstream of the second belt conveyance unit without lowering the conveyance speed of the first conveyance belt and the second conveyance belt more than necessary. It is possible to reliably prevent the undried ink from adhering to the side conveyance path and the conveyance roller pair.

1 is a side cross-sectional view showing an internal configuration of a printer 100, which is an example of an ink jet recording apparatus according to a first embodiment of the present invention. Partial enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 in the printer 100 of the first embodiment. 2 is a partially enlarged view near the boundary between the first belt conveyance unit 20 and the second belt conveyance unit 40 in FIG. Partial enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 in the printer 100 according to the second embodiment of the present invention. Partial enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 in the printer 100 according to the third embodiment of the present invention.

  Hereinafter, an ink jet recording apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing an internal configuration of an ink jet printer 100 which is an example of an ink jet recording apparatus according to the first embodiment of the present invention.

  As shown in FIG. 1, in the printer 100, a paper feed cassette 3 that is a paper storage unit is disposed below the inside of the printer main body 2. Inside the paper feed cassette 3, a predetermined number of sheets (for example, about 500 sheets) such as cut paper before printing, which is an example of a recording medium, is stacked and accommodated. A paper feeding device 4 is arranged on the downstream side of the paper feeding cassette 3 in the paper conveyance direction, that is, above the right side of the paper feeding cassette 3 in FIG. The sheet feeding device 4 separates and feeds the sheets P one by one toward the upper right of the sheet feeding cassette 3 in FIG. The paper feed cassette 3 can be pulled out horizontally from the front side of the main body 2 to replenish paper P.

  A manual paper feed tray 5 is provided outside the right side surface of the main body 2. In the manual feed tray 5, a recording medium having a size different from that of the paper P in the paper feed cassette 3, a recording medium that is difficult to pass through a curved conveyance path such as a thick paper, an OHP sheet, an envelope, a postcard, and a feed, Recording media that you want to feed by hand are placed one by one. A sheet feeding device 6 is disposed on the downstream side of the manual sheet feeding tray 5 in the sheet conveyance direction, that is, on the left side of the manual sheet feeding tray 5 in FIG. By the paper feeding device 6, the paper on the manual paper feeding tray 5 is separated and sent one by one toward the left in FIG.

  Further, the printer 100 includes a first paper transport path 7 therein. The first paper transport path 7 is located at the upper right in the paper feeding direction in terms of the paper feed cassette 3, and is located in the left of the manual paper feed tray 5. The paper P delivered from the paper feed cassette 3 is conveyed vertically upward along the side surface of the main body 2 by the first paper conveyance path 7, and the paper delivered from the manual paper feed tray 5 is conveyed substantially horizontally to the left. .

  A registration roller pair 8 is provided at the downstream end of the first paper transport path 7 with respect to the paper transport direction. Further, a first belt conveyance unit 20 and a recording unit 30 are disposed in the immediate vicinity of the registration roller pair 8 on the downstream side. The paper P sent out from the paper feed cassette 3 (or the manual paper feed tray 5) reaches the registration roller pair 8 through the first paper transport path 7. The registration roller pair 8 feeds the paper P toward the first belt conveyance unit 20 by correcting the oblique feeding of the paper P and timings the ink ejection operation performed by the recording unit 30. The first paper transport path 7 is provided with transport roller pairs for transporting the paper P at appropriate positions.

  A second belt conveyance unit 40 is disposed on the downstream side (left side in FIG. 1) of the first belt conveyance unit 20 with respect to the paper conveyance direction. The paper P on which the ink image is recorded by the recording unit 30 is sent to the second belt conveyance unit 40, and the ink ejected on the surface of the paper P is dried while passing through the second belt conveyance unit 40. The detailed configurations of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 will be described later.

  A decurler unit 9 is provided on the downstream side of the second belt conveyance unit 40 in the paper conveyance direction and in the vicinity of the left side surface of the printer main body 2. The paper P from which the ink has been dried by the second belt conveyance unit 40 is sent to the decurler unit 9, and the curl is corrected using a plurality of rollers arranged in the paper width direction.

  A second paper transport path 10 is provided on the downstream side (upper side in FIG. 1) of the decurler unit 9 with respect to the paper transport direction. When the double-sided recording is not performed, the paper P that has passed through the decurler unit 9 is discharged from the second paper transport path 10 to a paper discharge tray 11 provided outside the left side surface of the printer 100.

  A reverse conveyance path 12 for performing double-sided recording is provided above the printer main body 2 and above the recording unit 30 and the second belt conveyance unit 40. When performing double-sided recording, the recording on the first surface is completed, and the sheet P that has passed through the second belt conveying unit 40 and the decurler unit 9 is sent to the reverse conveying path 12 through the second sheet conveying path 10. . The paper P sent to the reverse conveyance path 12 is subsequently switched in the conveyance direction for recording on the second side, passes through the upper part of the printer main body 2 and is sent to the right side, and the first paper conveyance path 7 , And through the registration roller pair 8, the sheet is fed again to the first belt conveyance unit 20 with the second surface facing upward. Note that the second paper transport path 10 and the reverse transport path 12 are provided with transport roller pairs for transporting the paper P at appropriate positions, similarly to the first paper transport path 7.

  FIG. 2 is a partially enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 in FIG. Detailed configurations of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 will be described with reference to FIG. 2 in addition to FIG.

  The first belt conveyance unit 20 includes an endless first conveyance belt 21 that is wound around a first drive roller 22 and a first driven roller 23. The first conveying belt 21 is rotated counterclockwise in FIG. 2 by the first driving roller 22. The paper P sent out by the registration roller pair 8 (see FIG. 1) is held on the transport surface 21a (upper surface in FIG. 2) of the first transport belt 21 and moves in the direction of arrow X (from right to left) in FIG. Be transported.

  Here, since the first driving roller 22 is arranged on the downstream side in the paper conveying direction X, the conveying surface 21a of the first conveying belt 21 is pulled by the first driving roller 22, and therefore the tension of the conveying surface 21a. The sheet P can be stably conveyed. In addition to the first driving roller 22 and the first driven roller 23, one or more tension rollers that are inscribed in the first conveying belt 21 may be provided as necessary.

  A first paper suction unit 25 is provided at a location inside the first transport belt 21 and facing the back side of the transport surface 21 a of the first transport belt 21. The first sheet suction unit 25 is provided with a large number of air suction holes 25a on the upper surface, and is provided with a fan 25b inside, so that air can be sucked downward from the upper surface. The first transport belt 21 is also provided with a number of air suction holes (not shown). As a result, the first belt conveyance unit 20 conveys the paper P using the first conveyance belt 21 and the first paper suction unit 25 while adsorbing and holding the sheet P on the conveyance surface 21 a of the first conveyance belt 21.

  A recording unit 30 is disposed above the first belt conveyance unit 20. The recording unit 30 is supported at a height such that a predetermined interval (for example, 1 mm) is formed with respect to the conveyance surface 21a of the first conveyance belt 21, and is applied to the paper P that is sucked and held on the conveyance surface 21a. Recording heads Y, M, C, and K, which are line-type inkjet heads for recording images, are provided.

  The recording heads Y to K extend in the paper width direction (perpendicular to the paper surface in FIG. 2) perpendicular to the paper transport direction, and these four heads rotate along the rotation direction of the first transport belt 21. They are arranged in parallel from the upstream side to the downstream side in the moving direction. These recording heads Y to K are filled with inks of four different colors (yellow, magenta, cyan and black) from an ink tank (not shown).

  Corresponding to the image data information received from an external computer or the like, each of the recording heads Y to K sequentially ejects the respective inks toward the paper P attracted to the first transport belt 21, so that the paper P A full-color image in which four colors of yellow, magenta, cyan, and black are superimposed is recorded. Note that the printer 100 can also record a monochrome image.

  Further, these recording heads Y to K have a recording area that is equal to or larger than the maximum width of the paper P to be transported, and collectively with respect to the paper P that is sucked and transported by the first transport belt 21. An image for one line can be recorded, and high-speed printing is possible as compared with a serial type ink jet head in which the recording head reciprocates in the width direction of the paper P. As the ink ejection method for the recording heads Y to K, for example, a piezo method for ejecting ink using a piezo element (not shown), or a thermal ink jet method for generating air bubbles by a heating element and ejecting ink by applying pressure. Various methods can be applied.

  A second belt conveyance unit 40 is arranged adjacent to the downstream side of the first belt conveyance unit 20 with respect to the paper conveyance direction. The second belt conveyance unit 40 includes an endless second conveyance belt 41 wound around a second drive roller 42 and a second driven roller 43. The second conveyor belt 41 is rotated counterclockwise in FIG. 2 by the second drive roller 42. The sheet P on which an image is recorded by the recording unit 30 and conveyed in the direction of arrow X by the first belt conveyance unit 20 is transferred to the second conveyance belt 41, and in the direction of arrow Z in FIG. 2 (from lower right to upper left). It is conveyed.

  Similar to the first belt conveyance unit 20, the second drive roller 42 is arranged on the downstream side in the paper conveyance direction Z, so that the conveyance surface 41 a (upper surface in FIG. 2) of the second conveyance belt 41 is the second drive roller 42. Therefore, the tension of the transport surface 41a can be increased, and the paper P can be stably transported. In addition to the second driving roller 42 and the second driven roller 43, one or more tension rollers that are inscribed in the second conveying belt 41 may be provided as necessary.

  A second paper suction unit 45 is provided at a location inside the second transport belt 41 and facing the back side of the transport surface 41 a of the second transport belt 41. The second sheet suction unit 45 is provided with a number of air suction holes 45a on the upper surface and is provided with a fan 45b inside so that air can be sucked downward from the upper surface. The second conveyor belt 41 is also provided with a number of air suction holes (not shown). As a result, the second belt conveyance unit 40 conveys the paper P using the second conveyance belt 41 and the second paper suction unit 45 while adsorbing and holding the paper P on the conveyance surface 41 a of the second conveyance belt 41.

  In the printer 100 of the present invention, printing is performed in the recording unit 30 by disposing the second belt conveyance unit 40 on the downstream side of the first belt conveyance unit 20 that is disposed opposite to the recording unit 30 in the paper conveyance direction. Then, the sheet P is continuously conveyed by the belt. Therefore, it is possible to secure the ink drying time during the conveyance of the paper P by the second belt conveyance unit 40, and to the second paper conveyance path 10, the reverse conveyance path 12, and the conveyance roller pair provided in them. Adhesion of dry ink can be prevented.

  Further, by dividing the belt conveyance unit into the first belt conveyance unit 20 and the second belt conveyance unit 40, the cost can be reduced as compared with a configuration using a large-diameter conveyance belt. Further, when the paper P is jammed in the recording unit 30, the jam processing can be performed by retracting only the first belt conveyance unit 20. As a result, the belt retracting area can be reduced, and the printer 100 can be reduced in size and space.

  Note that when the first conveying belt 21 is configured by arranging a plurality of narrow endless belts in the paper width direction, a wavy phenomenon in which the paper P is recessed between the belts occurs. Therefore, by making the width direction dimension of the first conveyance belt 21 wider than the maximum printing width of the recording unit 30, the sheet P attracted to the conveyance surface 21a can be maintained in a flat state, and recording can be performed. Stable printing can be performed in the section 30.

  Further, the second belt conveyance unit 40 is arranged such that an angle θ formed by the conveyance surface 21a of the first conveyance belt 21 and the conveyance surface 41a of the second conveyance belt 41 is an obtuse angle. By arranging the first belt conveyance unit 20 and the second belt conveyance unit 40 in this manner, it is possible to effectively change the conveyance speed of the paper P transferred from the first belt conveyance unit 20 to the second belt conveyance unit 40. Can be absorbed into.

  FIG. 3 is a partially enlarged view of the vicinity of the boundary between the first belt conveyance unit 20 and the second belt conveyance unit 40 in FIG. A mechanism for absorbing fluctuations in the conveyance speed of the paper P delivered from the first belt conveyance unit 20 to the second belt conveyance unit 40 will be described with reference to FIG. Assuming that the transport speed of the paper P by the first transport belt 21 is S1 and the transport speed of the paper P by the second transport belt 41 is S2, normally, S1 and S2 are set to be equal, and the speed difference is 0. is there. At this time, the paper P held in a bridging manner by the first transport belt 21 and the second transport belt 41 is bent at the boundary between the first transport belt 21 and the second transport belt 41, and the paper P is bent in a loop shape. Will occur.

  Now, assuming that S2 has become a predetermined amount faster than S1 for some reason, the sheet P is pulled in the direction of the arrow Z when the leading edge of the sheet P is attracted to the second transport belt 41. Although the amount of bending of the paper P is reduced by this pulling force (broken line L1 in FIG. 3), a predetermined amount of initial bending has occurred in the paper P in advance. Therefore, no tension is applied to the portion of the paper P that is attracted to the first conveying belt 21 until the initial deflection is eliminated.

  On the other hand, assuming that S2 is a predetermined amount later than S1, when the leading edge of the paper P is adsorbed by the second transport belt 41, stress acts on the paper P in the right direction in the figure. Due to this stress, the amount of deflection of the paper P increases from the initial deflection (the one-dot chain line L2 in FIG. 2), but the boundary portion between the first belt conveyance unit 20 and the second belt conveyance unit 40 can be further formed with deflection. is there. Therefore, if the amount of deflection is less than the allowable amount, no stress is transmitted to the portion of the paper P that is attracted to the first transport belt 21.

  Therefore, if the speed difference between S1 and S2 is within a predetermined amount, the deflection is not completely eliminated until the trailing edge of the paper P has passed through the first belt conveyance unit 20, and even if the deflection is additionally formed. By setting the amount to be equal to or less than the allowable amount, it is possible to prevent the sheet P adsorbed on the first conveyance belt 21 from being displaced, and to suppress the occurrence of color displacement.

  Moreover, in the said embodiment, the 1st conveyance belt 21 is arrange | positioned by arrange | positioning the 2nd driven roller 43 around which the 2nd conveyance belt 41 is wound below the 1st drive roller 22 around which the 1st conveyance belt 21 is wound. A surface Q (see FIG. 2) obtained by extending the transport surface 21 a in the sheet transport direction intersects the transport surface 41 a of the second transport belt 41.

  With this configuration, the leading edge of the sheet P is reliably attracted and held on the conveyance surface 41 a, so that the sheet P can be smoothly transferred from the first conveyance belt 21 to the second conveyance belt 41. Further, since the space R (see FIG. 2) is formed below the surface Q, the sheet P can be easily bent.

  The angle θ formed by the conveyance surface 21a of the first conveyance belt 21 and the conveyance surface 41a of the second conveyance belt 41 is preferably 140 ° or more and 170 ° or less. When the angle θ is smaller than 140 °, the approach angle of the paper P with respect to the transport surface 41a of the second transport belt 41 increases, and the impact transmitted to the paper P during delivery from the transport surface 21a to the transport surface 41a increases. If the angle θ is greater than 170 °, the degree of bending of the sheet P at the boundary between the first conveying belt 21 and the second conveying belt 41 is too small to sufficiently form the sheet P, and the first conveying belt cannot be formed. The influence of the conveyance speed difference between the belt 21 and the second conveyance belt 41 is easily transmitted.

  In addition, it is preferable that the relationship between the conveyance speed S1 of the first conveyance belt 21 and the conveyance speed S2 of the second conveyance belt 41 satisfies S1 ≧ S2. By setting S1 and S2 in this way, when the paper P is transferred from the first transport belt 21 to the second transport belt 41, the pulling force by the second belt transport unit 40 does not act on the paper P, and the first P The deviation of the paper P in the belt conveying unit 20 can be prevented more reliably. Further, the initial deflection can be reliably formed in the bent portion of the paper P.

  Further, if the suction force per unit area of the paper P in the first belt transport unit 20 is F1, and the suction force per unit area of the paper P in the first belt transport unit 20 is F2, the relationship between F1 and F2 is F1 ≧ It is preferable to satisfy F2. By setting F1 and F2 in this way, even when a large conveyance speed difference that cannot be absorbed by the deflection of the paper P occurs, the deviation of the paper P occurs in the second belt conveyance unit 40 having a weak suction force. Accordingly, it is possible to more reliably prevent the sheet P from being shifted in the first belt conveyance unit 20.

  FIG. 4 is a partially enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 of the inkjet printer 100 that is an example of the inkjet recording apparatus according to the second embodiment of the present invention. . In the present embodiment, a gear (not shown) fixed to the rotation shaft of the first drive roller 22 constituting the first belt conveyance unit 20 and the rotation of the second drive roller 42 constituting the second belt conveyance unit 40. A drive input gear 47 connected to both gears (not shown) fixed to the shaft and a motor 49 that rotationally drives the drive input gear 47 are provided. Since the configuration of other parts is the same as that of FIG. 2 of the first embodiment, description thereof is omitted.

  According to this embodiment, since the first drive roller 22 and the second drive roller 42 are connected to the common drive input gear 47, the transport speed S <b> 1 of the first transport belt 21 and the transport speed of the second transport belt 41. S2 can be easily set to a substantially constant speed, and a substantially constant speed state can be easily maintained.

  Further, by adjusting the diameter ratio of the first driving roller 22 and the second driving roller 42 or the gear ratio of the gear fixed to the rotation shaft of the first driving roller 22 and the second driving roller 42, the conveyance speed S1, S2 can be set to a desired speed, and the set speed can be easily maintained. For example, when the transport speeds S <b> 1 and S <b> 2 are set so as to satisfy S <b> 1 ≧ S <b> 2 as in the first embodiment, the diameter of the second driving roller 42 is equal to or larger than the diameter of the first driving roller 22, or the second driving roller The diameter of the gear fixed to the rotation shaft 42 may be equal to or larger than the diameter of the gear fixed to the rotation shaft of the first drive roller 22.

  In addition, since the first driving roller 22 and the second driving roller 42 are driven using one motor 49, the cost is lower than the configuration in which the first driving roller 22 and the second driving roller 42 are driven by separate motors. Is also advantageous.

  FIG. 5 is a partially enlarged view of the vicinity of the first belt conveyance unit 20, the recording unit 30, and the second belt conveyance unit 40 of the inkjet printer 100 that is an example of the inkjet recording apparatus according to the third embodiment of the present invention. . In the present embodiment, a drying device 50 that blows an air flow onto the paper P sucked and held on the transport surface 41 a is provided at a position facing the transport surface 41 a of the second transport belt 41. Since the configuration of other parts is the same as that of FIG. 2 of the first embodiment, description thereof is omitted.

  According to the present embodiment, the ink on the paper P is forcibly dried by the drying device 50 while the paper P is being transported by the second belt transport unit 40. Therefore, the ink on the paper P can be dried in a shorter time, and the adhesion of the ink to the decurler unit 9 and the pair of transport rollers can be reliably prevented without lowering the transport speeds S1 and S2 more than necessary. it can.

  In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, as means for sucking and holding the paper P on the first transport belt 21 and the second transport belt 41, air suction holes are formed in the first transport belt 21 and the second transport belt 41, and the inside A vacuum suction method is used in which the paper P is sucked and held using the first paper suction unit 25 and the second paper suction unit 45 provided with the fans 25b and 45b. In place of the reduced pressure adsorption method, a charging device for charging the first transport belt 21 and the second transport belt 41 is provided, and between the transport surfaces 21 a and 41 a of the first transport belt 21 and the second transport belt 41 and the paper P. It is also possible to use an electrostatic attraction method in which a potential difference is generated in the first transport belt 21 and the second transport belt 41 so that the paper P is electrostatically attracted and held.

  In the above embodiment, the ink jet recording apparatus that transports the paper P in the horizontal direction from the paper feed cassette 3 or the manual paper feed tray 5 has been described as an example. Alternatively, the present invention can be applied to a vertical conveyance type inkjet recording apparatus that conveys the paper P from the manual paper feed tray 5 toward the paper discharge tray on the upper surface of the apparatus.

  In the above embodiment, an inkjet recording apparatus using four colors of ink of yellow, magenta, cyan, and black has been described in order to obtain a full-color image. However, an inkjet recording apparatus including colored inks of different hues has been described. It can also be used for ink jet recording apparatuses having different colors.

  INDUSTRIAL APPLICABILITY The present invention can be used in an inkjet recording apparatus that performs recording by ejecting ink onto a recording medium such as paper in a recording apparatus such as a facsimile, a copying machine, and a printer. It can be used for an ink jet recording apparatus provided with a recording head. By using the present invention, it is possible to provide an ink jet recording apparatus that can prevent both the adhesion of undried ink to a conveyance path, a pair of conveyance rollers, and the like and the occurrence of color misregistration in a recording unit with a simple configuration.

20 1st belt conveyance part 21 1st conveyance belt 21a Conveyance surface (1st conveyance belt)
22 1st driving roller 23 1st driven roller 25 1st paper suction part 30 Recording part 40 2nd belt conveyance part 41 2nd conveyance belt 41a Conveyance surface (2nd conveyance belt)
42 Second driving roller 43 Second driven roller 45 Second paper suction unit 47 Driving input gear 49 Motor 50 Drying device 100 Printer (inkjet recording device)
P paper (recording medium)
Y, M, C, K Recording head

Claims (8)

An endless first conveying belt that sucks and holds the recording medium and conveys the recording medium, a first driving roller that rotationally drives the first conveying belt, and the first driving belt that rotatably supports the first conveying belt. A first belt transport unit having a first driven roller;
A recording unit having a line head type recording head disposed opposite to the first belt conveyance unit and discharging ink onto a recording medium conveyed by the first conveyance belt;
An endless second conveying belt that is disposed adjacent to the downstream side of the first belt conveying unit with respect to the recording medium conveying direction and conveys the recording medium by sucking and holding the recording medium, and rotationally driving the second conveying belt A second belt transport unit, and a second driven roller that rotatably supports the second transport belt together with the second drive roller;
With
An ink jet recording apparatus in which an angle formed between a transport surface of the first transport belt and a transport surface of the second transport belt is an obtuse angle.   The inkjet recording apparatus according to claim 1, wherein a surface obtained by extending a conveyance surface of the first conveyance belt in a conveyance direction of the recording medium intersects with a conveyance surface of the second conveyance belt.   The inkjet recording apparatus according to claim 1, wherein the first drive roller and the second drive roller are connected to the same drive input gear.   The inkjet according to any one of claims 1 to 3, wherein an angle formed by a conveyance surface of the first conveyance belt and a conveyance surface of the second conveyance belt is 140 ° or more and 170 ° or less. Recording device.   5. The recording medium conveying speed of the first conveying belt is S1, and the recording medium conveying speed of the second conveying belt is S2, and S1 ≧ S2 is satisfied. An ink jet recording apparatus according to claim 1.   F1 ≧ F2 is satisfied, where F1 is an adsorption force per unit area of the recording medium with respect to the first conveyance belt, and F2 is an adsorption force per unit area of the recording medium with respect to the second conveyance belt. The ink jet recording apparatus according to any one of claims 1 to 5.   The inkjet recording apparatus according to any one of claims 1 to 6, wherein a dimension in the width direction of the first conveying belt is wider than a maximum printing width of the recording unit.   8. The ink jet recording apparatus according to claim 1, further comprising a drying device that dries the ink on the recording medium that is sucked and held on the transport surface of the second transport belt.

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