JP2008179012A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dry the ink on a sheet after printed, surely in a short time without impairing adverse influence to an inkjet head. <P>SOLUTION: A rotary drum 13 formed of a metal with many mobile suction holes is rotated outside a fixed drum 38 with many immobile suction holes. The sheet P after printed is sucked to the peripheral surface of the rotary drum 13 by discharging air outside of the fixed drum 38 by a suction fan. The sheet P is made to sequentially pass the vicinity of a plurality of heaters 15, whereby the ink on the sheet P is dried. A sheet drying part 12 with the rotary drum 13, the fixed drum 38 and the plurality of heaters 15 etc. is set independently of a sheet conveying part 10 and a printing part 11. Hence effects given by heat of the heaters 15 to the inkjet heads 30-33 can be reduced, so that printing and drying can be carried out by suitable conditions, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs printing by spraying ink onto a sheet from a number of nozzles aligned in a direction crossing a sheet conveyance direction.

  In an ink jet recording apparatus, a serial printer performs printing by spraying ink on a sheet while moving an ink jet head in a paper width direction (a direction orthogonal to the sheet conveying direction) with respect to a sheet passing through a printing unit. On the other hand, the line printer performs printing for each line by an inkjet head having a large number of nozzles in the sheet passing width direction, and therefore has a higher printing speed than a serial printer. In other words, the printing time for one sheet is short, and the sheet conveyance speed during printing is fast.

  When printing a plurality of sheets continuously with a serial printer or line printer, in the former serial printer, the preceding sheet is discharged onto the discharge tray until the subsequent sheet is discharged and stacked. Therefore, it is possible to secure a sufficient time for the ink of the preceding sheet to dry. For this reason, the so-called back stain, in which the ink on the preceding sheet stains the back surface of the succeeding sheet, hardly occurs.

  On the other hand, in the latter line printer, the sheet conveyance speed is fast, and the time until the succeeding sheet is superimposed on the preceding sheet on the discharge tray is short. For this reason, the ink on the preceding sheet does not dry, and there is a risk that backside stains will occur. In particular, a line printer may print an image with a very high printing rate compared to a character image, such as a color photograph or a color illustration. In this case, since the amount of ink used for printing is large, the tendency of back stain is further increased.

  For example, Patent Documents 1 and 2 disclose techniques for preventing such a problem.

  Of these, Patent Document 1 performs printing with an inkjet head on a sheet (printing medium) conveyed along a cylindrical roll. The sheet is heated via a heat source from the inside, and the sheet passes through the roll. Is heated to raise the temperature to shorten the ink drying time.

On the other hand, in Patent Document 2, after printing by a nozzle unit on a sheet (printing medium) carried on the outer peripheral surface of a rotatable drum, the sheet carried on the drum is dried by sending hot air from a drying means. To promote.
Japanese Patent Laid-Open No. 5-16341 Japanese Patent Laid-Open No. 10-138525

  However, the above-described Patent Documents 1 and 2 have a problem that heating of the sheet also affects the printing unit, which limits the heating temperature and makes it difficult to dry the ink in a short time. It was.

  That is, in Patent Document 1, the platen is heated to 40 to 60 degrees. This is because if the temperature is too high, the ink solvent evaporates, the ink viscosity increases, and nozzle clogging may occur. For this reason, the temperature cannot be further increased to speed up the drying of the ink.

  On the other hand, in Patent Document 2, since printing and ink drying are performed on the outer peripheral surface of the same drum, the heated portion of the drum reaches the printing unit. As in Patent Document 1, it is necessary to suppress the temperature of the drying means to such an extent that printing is not adversely affected.

  Therefore, an object of the present invention is to provide an ink jet recording apparatus that can dry ink on a sheet in a short time without affecting printing on the sheet.

  The invention according to claim 1 is a sheet transport unit having a sheet transport member that carries and transports a sheet on the surface, and a plurality of nozzles aligned in a direction intersecting a transport direction of the sheet transported by the sheet transport member The present invention relates to an ink jet recording apparatus that includes an ink jet head that prints by ejecting ink onto a print surface of a sheet. An ink jet recording apparatus according to the present invention includes a rotating body that supports a sheet separated from the sheet conveying member after printing on an outer peripheral surface so that a printing surface faces outward, and rotates the rotating body to adsorb the sheet. It is characterized by comprising: an adsorbing means; and a heating element that is disposed so as to face the outer peripheral surface of the rotating body and dries the ink of the sheet adsorbed on the rotating body.

  According to a second aspect of the present invention, there is provided a sheet conveying unit having a sheet conveying member that carries and conveys a sheet on the surface, and a plurality of nozzles aligned in a direction intersecting a conveying direction of the sheet conveyed by the sheet conveying member The present invention relates to an ink jet recording apparatus that includes an ink jet head that prints by ejecting ink onto a print surface of a sheet. The ink jet recording apparatus according to the present invention has a plurality of movable suction holes for adsorbing a sheet separated from the sheet conveying member after printing on the outer peripheral surface using negative air pressure so that the printing surface faces outward. A rotating member, a duct member having a stationary suction hole that is fixedly disposed inside the rotating member, and a sheet ink that is disposed so as to face the outer peripheral surface of the rotating member and is adsorbed by the rotating member And a heating element that dries.

  According to a third aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the rotating body has a plurality of movable suction holes formed in a hollow shape and penetrating in a front-back direction, and the suction unit includes: It is a suction device that sucks air from the back surface side of the rotating body through the movable suction hole to adsorb the sheet to the outer peripheral surface of the rotating body.

  According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect, the suction device is fixedly arranged inside the rotating body and has a plurality of stationary suction holes in a portion corresponding to the movable suction hole. A duct member, and a suction fan that sucks air from the inside of the duct member to adsorb a sheet to the outer peripheral surface of the rotating body through the stationary suction hole and the movable suction hole. It is a feature.

  According to a fifth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to fourth aspects, the first discharge path serving as a discharge path for the sheet separated from the sheet conveying member after printing, and the rotation An adsorbing unit that adsorbs the sheet to the body and a separating unit that separates the sheet from the rotating body, and the adsorbing unit and the separating unit are provided in the first discharge path. It is characterized by.

  According to a sixth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to fourth aspects, the first discharge path serving as a discharge path for the sheet separated from the sheet conveying member after printing, and the rotation An adsorbing unit that adsorbs the sheet to the body, and a separating unit that separates the sheet from the rotating body, wherein the adsorbing unit is provided in the first discharge path, and the separating unit includes the first The second discharge path is different from the first discharge path.

  The invention according to claim 7 is the ink jet recording apparatus according to any one of claims 2, 4 to 6, wherein the duct member is a non-adsorption portion having no stationary suction hole at a portion corresponding to the separation portion. And the separation part has a separation member for separating the sheet adsorbed on the outer peripheral surface of the rotating body.

  According to an eighth aspect of the present invention, in the inkjet recording apparatus according to any one of the first to seventh aspects, the heat of the heating element is transmitted to the inkjet head surrounding the rotating body. It is characterized by providing a cover member to prevent.

  The invention according to claim 9 is the ink jet recording apparatus according to any one of claims 1 to 8, wherein the rotating body is rotated a plurality of times and dried on one sheet adsorbed on the rotating body. It is characterized by that.

  A tenth aspect of the present invention is the ink jet recording apparatus according to any one of the first to ninth aspects, wherein the rotating body is a metal cylindrical member.

  According to an eleventh aspect of the present invention, in the ink jet recording apparatus according to any one of the first to ninth aspects, the rotating body is a belt-shaped member.

  According to the first aspect of the present invention, the rotating body for drying the ink of the printed sheet is provided independently of the sheet conveying member that carries and conveys the sheet when performing printing, and the adsorbing means The heating element is disposed in association with the rotating body. That is, since the rotating body, the suction means, and the heating element for drying the ink on the sheet are all provided separately from the sheet conveying member and the inkjet head, the drying of the ink is less than the printing by the inkjet head. Does not affect. Since the printing condition and the drying condition can be individually set without being influenced by the other, it is possible to set each of them appropriately.

  According to the invention of claim 2, the rotating body for drying the ink of the sheet after printing is provided independently of the sheet conveying member that carries and conveys the sheet when performing printing, and the duct member The heating element is disposed in association with the rotating body. That is, the rotating body, duct member, and heating element for drying the ink on the sheet are all provided separately from the sheet conveying member and the inkjet head. Does not affect. Since the printing condition and the drying condition can be individually set without being influenced by the other, it is possible to set each of them appropriately.

  According to the invention of claim 3, the suction device can adsorb the sheet to the outer peripheral surface of the rotating body by sucking air from the back surface side of the rotating body through the movable suction hole. Further, the moisture of the ink evaporated at the time of drying escapes not only from the front surface side of the sheet but also from the back surface side through the movable suction hole, so that drying can be performed efficiently.

  According to the invention of claim 4, the suction fan sucks air from the inside of the duct member and adsorbs the sheet to the outer peripheral surface of the rotating body through the fixed suction hole of the duct member and the movable suction hole of the rotating body. be able to.

  According to the invention of claim 5, the suction part and the separation part are provided in the first discharge path for discharging the sheet after printing, and the sheet after drying the ink is passed through the first discharge path. Therefore, it is not necessary to provide a separate discharge path for discharging the sheet after ink drying.

  According to the invention of claim 6, with respect to the rotating body, the suction portion to which the sheet is sucked is provided in the first discharge path, and the separation portion from which the sheet is separated is provided in the second discharge path, Since the adsorption and separation of the sheet with respect to the rotating body can be performed independently at different places, the continuous printing speed of the sheet resulting from the drying (discharged after the second sheet in the case of continuous printing) There is almost no decrease in the number of printed sheets per unit time.

  According to the seventh aspect of the present invention, the leading edge of the sheet adsorbed on the outer peripheral surface of the rotating body stops being sucked when it reaches the portion corresponding to the non-adsorbing portion of the duct member. This sheet is separated from the outer peripheral surface of the rotating body by the separating member.

  According to the invention of claim 8, by covering the periphery of the rotating body and the heating element with the cover member, it is possible to prevent the heat for drying the ink from being transmitted to the inkjet head.

  According to the invention of claim 9, for example, when the ink on the sheet adsorbed on the outer peripheral surface of the rotating body is not sufficiently dried by one rotation of the rotating body, by rotating the rotating body a plurality of times, It can be dried sufficiently.

  According to the invention of claim 10, since the rotating body is a metal cylindrical member, the temperature of the rotating body is easily raised by the heating element, and therefore drying of the ink can be promoted from the back side of the sheet. .

  According to the eleventh aspect of the present invention, since the rotating body is a belt-like member, it is possible to increase the degree of freedom in design for securing the arrangement space.

  Hereinafter, the best embodiment of the present invention will be described in detail with reference to the drawings. In addition, in each drawing, the member etc. which attached | subjected the same code | symbol are the same structures, The duplication description about these shall be abbreviate | omitted suitably. Moreover, in each drawing, members and the like that are not necessary for the description are omitted as appropriate.

<Embodiment 1>
An ink jet recording apparatus 1 according to the present invention will be described with reference to FIGS. Among these, FIG. 1 is a diagram schematically showing the ink jet recording apparatus 1 viewed from the front side (front side). FIG. 2 is a view showing a cross section of the rotary drum 13 taken along a plane including its axis. FIG. 3 is a view showing a cross section of the fixed drum 38 taken along a plane including its axis. In the following description, “upstream side” and “downstream side” refer to an upstream side and a downstream side along the conveyance direction (movement direction) of the sheet P. Here, the sheet P refers to a recording medium such as plain paper, coated paper, or art paper on which printing is performed with ink.

  The ink jet recording apparatus 1 includes a sheet conveying unit 10, a printing unit 11, and a sheet drying unit 12. The sheet drying unit 12 includes a rotating drum (rotating body) 13 and a suction device (suction unit) 14. And a heater (heating element) 15 are disposed.

  As shown in FIG. 1, the sheet P is supplied from the sheet feeding unit 16 to the sheet conveying unit 10. In the sheet feeding unit 16, a sheet feeding cassette 17, a sheet feeding roller 18, a feeding roller 20, a retard roller 21, a conveyance roller pair 22 and 23, and a registration roller pair 24 are disposed almost sequentially from the upstream side. . The sheets P stored in a stacked state in the paper feed cassette 17 are fed in order from the highest one by the paper feed roller 18. The fed sheet P is separated by the feeding roller 20 and the retard roller 21 and conveyed downstream. The conveyed sheet P is abutted against the nip of the stopped registration roller pair 24 by the conveying roller pairs 22 and 23 to correct skewing. Thereafter, the sheet P is supplied to the sheet conveying unit 10 by the registration roller pair 24 rotating in the direction of the arrow.

  The sheet conveying unit 10 is provided with a downstream driving roller 25, an upstream driven roller 26, and a conveying belt (sheet conveying member) 27 stretched over them. The conveyor belt 27 is rotated in the direction of the arrow R27 by the rotation of the driving roller 25 in the direction of the arrow. A portion of the conveying belt 27 located in the upper half, that is, a portion located downstream of the driven roller 26 and upstream of the driving roller 25 along the rotation direction carries the sheet P on the surface. It becomes the sheet carrying surface 28. The sheet P supplied from the sheet feeding unit 16 is carried on the sheet carrying surface 28 of the conveying belt 27 and passes below the printing unit 11 as the conveying belt 27 rotates in the direction of arrow R27. .

  In the printing unit 11, ink jet heads 30, 31, 32, and 33 for cyan, magenta, yellow, and black are arranged in order from the upstream side. Each of the inkjet heads 30 to 33 has an ink discharge surface 34 on the lower surface thereof, and this ink discharge surface 34 faces the sheet carrying surface 28 of the conveying belt 27 via a predetermined gap (about 1 mm). Yes. On the ink ejection surface 34, a large number of fine nozzles (not shown) are formed in a line along the belt width direction of the transport belt 27 (the direction perpendicular to the sheet transport direction and the same as the sheet passing width direction of the sheet P). Aligned. Here, the line shape includes not only the case where the lines are arranged in a strict sense but also the case where the lines are arranged in a staggered manner. When the sheet P carried on the sheet carrying surface 28 passes below the ink jet heads 30 to 33 for each color as the conveyance belt 27 rotates, the ink from the nozzles for each color is generated based on the image signal of the control means 29. Is ejected and sprayed. As a result, a full color image is formed on the sheet P by printing with four colors of ink of cyan, magenta, yellow, and black.

  In general, the ink includes oil-based ink and water-based ink. In this embodiment, water-based ink is used. Since water-based inks are water, the solvent is higher than oil-based inks, and the viscosity is low, so when high-definition printing is performed using many nozzles. Is suitable. On the other hand, since water as a solvent is less likely to penetrate into the sheet as compared with oil, it dries less than oil-based ink. For this reason, for example, in an ink jet recording apparatus that performs four-color full-color printing at high speed, a sheet drying unit described later that can dry ink in a short time is particularly effective.

  As described above, the sheet P on which the four-color full-color printing is performed with the water-based ink in the printing unit 11 is separated from the transport belt 27 and moves to the first discharge path 35.

  The first discharge path 35 is a sheet conveyance path that connects the upstream sheet conveyance unit 10 and the downstream sheet drying unit 12, and a separation member 36 is disposed on the upstream side. The separation member 36 is disposed so that the tip thereof is close to the downstream end of the sheet carrying surface 28 of the conveying belt 27 described above. The separating member 36 separates the sheet P from the conveying belt 27 by inserting the leading end between the leading end of the printed sheet P and the sheet carrying surface 28 of the conveying belt 27. The separated sheet P is supplied to the sheet drying unit 12.

  As described above, the sheet drying unit 12 is provided with the rotating drum (rotating body) 13, the suction device 14, and the heater (heating element) 15, and the cover member 37 surrounding them is provided. It is arranged. In the present embodiment, the suction device 14 is configured by a suction device having a fixed drum 38 as a duct member and a suction fan 40.

  As shown in FIG. 2, the rotating drum 13 is made of a thin cylindrical metal. The diameter of the outer peripheral surface of the rotary drum 13 is such that, for example, a longitudinal A3 size sheet P (A3 sheet P conveyed with its long side oriented along the conveying direction) can be adsorbed without overlapping. Is set. Therefore, in the case of an A4 size sheet P, two sheets can be adsorbed simultaneously in a landscape orientation. A large number of movable suction holes 41 having a small diameter, which are penetrated in the front and back direction, are formed in the entire outer peripheral surface of the rotary drum 13. The length of the rotary drum 13 in the axial direction is longer than the maximum sheet passing width of the sheet P attracted to the outer peripheral surface thereof. One end 13 a and the other end 13 b of the rotary drum 13 are rotatably supported by a bearing 44. A ring gear 42 is fitted on the outer peripheral surface of one end 13 a of the rotary drum 13. A drive gear 43 is engaged with the ring gear 42, and the rotary drum 13 is rotated in the direction of arrow R 13 through the ring gear 42 by the rotation of the drive gear 43.

  It is also possible to use a planetary gear as a mechanism for rotating the rotary drum 13. In this case, the ring gear fitted to the outer peripheral surface of one end of the rotary drum 13 corresponds to the sun gear, and another ring gear (not shown) constituted by internal teeth is disposed outside the sun gear. The sun gear and another ring gear may be engaged with a pinion rotatably supported by a carrier (not shown). In this case, the rotating drum can be rotated via the sun gear by rotating the carrier or another ring gear.

  One end portion 13a and the other end portion 13b of the rotating drum 13 are opened, and both end portions in the axial direction of the fixed drum 38 to be described later project from these opening portions. In the present embodiment, the rotational speed (circumferential speed) of the rotary drum 13 is set to be the same as the rotational speed (moving speed) of the above-described conveyor belt 27, and the continuous printing speed of the sheet drying unit 12 is provided. I try to prevent the decline.

  The fixed drum 38 shown in FIG. 3 is disposed in a fixed state inside the rotating drum 13 described above. The fixed drum 38 is formed such that the axial length is longer than that of the rotating drum, and the outer peripheral surface has a diameter smaller than the inner peripheral surface of the rotating drum. As shown in FIG. 1, the fixed drum is disposed so that its axis coincides with the axis of the rotating drum, and an appropriate distance is provided between the outer peripheral surface of the fixed drum and the inner peripheral surface of the rotating drum. A gap G is formed. As shown in FIG. 3, a stationary suction hole 45 penetrating in the front and back direction is formed in the outer peripheral surface of the fixed drum 38. The diameter of the stationary suction hole 45 is set larger than the diameter of the movable suction hole 41 of the rotary drum 13 described above. A number of fixed suction holes 45 of the fixed drum 38 are bored over substantially the entire circumference of the fixed drum 38. However, in the circumferential region indicated by the arrow in FIG. 1, as shown in FIG. 3, a non-adsorption portion A in which a through hole is not formed over the entire length in the axial direction is provided. This is for facilitating separation of the sheet P adsorbed on the outer peripheral surface of the rotary drum 13 as will be described later. One end (the upper end in FIG. 3) of the fixed drum 38 is closed, and a suction fan 40 is attached to the other end (the lower end in FIG. 3). It has been.

  The suction fan 40 discharges the air inside the fixed drum 38 to the outside, thereby reducing the internal pressure inside. As a result, air is sucked from the many stationary suction holes 45 of the fixed drum 38. The gap G between the outer peripheral surface of the fixed drum 38 and the inner peripheral surface of the rotating drum 13 becomes negative pressure, and the air outside the rotating drum 13 is sucked inward through the movable suction hole 41. Thereby, the sheet P can be adsorbed to the outer peripheral surface of the rotary drum 13.

  The heater 15 is formed in a rod shape, and is disposed so as to be close to the outer peripheral surface of the rotary drum 13 and along the bus bar. As the heater 15, a halogen heater or a far infrared heater is used. In the example shown in FIG. 1, five heaters 15 are arranged in a substantially half circumference of the rotary drum 13. That is, the five heaters 15 are arranged on the outer peripheral surface of the rotary drum 13 on the side far from the ink jet heads 30 to 33, thereby making the ink jet heads 30 to 33 less susceptible to the heat of the plurality of heaters 15. ing. In the present embodiment, the heater 15 mainly dries the ink on the sheet P directly by its radiant heat. Note that the number of heaters 15 and the positions of the heaters 15 are not limited to those described above.

  The cover member 37 is formed in a substantially cylindrical shape. Inside the cover member 37, the rotary drum 13, the fixed drum 38, the suction fan 40, and the heater 15 are disposed. The cover member 37 covers substantially the whole of these, and a dry space R having an annular shape as viewed from the front side is formed between the inner peripheral surface of the cover member 37 and the outer peripheral surface of the rotary drum 13. Yes. The plurality of heaters 15 described above are disposed in the drying space R. A sheet carry-in port 46 for guiding the sheet P to the sheet drying unit 12 is formed at a portion where the first discharge path 35 and the cover member 37 intersect with each other. A portion of the rotary drum 13 that is located immediately downstream of the sheet carry-in port 46 is an adsorption portion 47 where the adsorption of the sheet P is started. The sheet P is adsorbed on the outer peripheral surface of the rotary drum 13 in order from the front end of the sheet P. In addition, a sheet carry-out port 48 is formed in the cover member 37 at a position separated from the sheet carry-in port 46 by about 3/4 of the rotation direction of the rotary drum 13. As shown in FIG. 1, the non-adsorption portion A of the fixed drum 38 is arranged at a position corresponding to the upstream side of the sheet discharge port. A part of the outer peripheral surface of the rotating drum 13 corresponding to the non-adsorption portion A is a separation portion 49. The cover member 37 having the above-described configuration prevents heat generated by the heater 15 from being transmitted to the inkjet heads 30 to 33.

  In the sheet drying unit 12 having the above-described configuration, as shown in FIG. 1, when the printed sheet P is supplied in a state where the rotary drum 13 and the suction fan 40 are rotated and the plurality of heaters 15 are turned on. The sheet P is adsorbed to the outer peripheral surface of the rotary drum 13 by the suction fan 40 and passes below the plurality of heaters 15 to dry the ink. The sheet P from which the ink has been dried is separated from the rotary drum 13 and supplied to the sheet discharge unit 50 through the sheet carry-out port 48.

  The sheet discharge unit 50 includes a second discharge path 51 that extends downstream from the sheet carry-out port 48. In the second discharge path 51, a separation claw (separation member) 52, a conveyance roller pair 53, a switching flapper 54, a conveyance roller pair 55, 56, a discharge roller pair 57, and a discharge tray 58 are arranged in this order from the upstream side. It is installed. In the above-described sheet drying unit 12, the sheet P on which ink has been dried by being adsorbed to the outer peripheral surface of the rotary drum 13 does not receive a suction action at the non-adsorption unit A when the leading end reaches the non-adsorption unit A. The tip is lifted from the outer peripheral surface of the rotary drum 13. The above-mentioned control means 29 arrange | positions the separation nail | claw 52 in the separation position shown as a continuous line according to this timing. The separation claw 52 disposed at the separation position is inserted between the outer peripheral surface of the rotary drum 13 and the front end of the sheet P at the front end. As a result, the sheet P is separated from the outer peripheral surface of the rotary drum 13 at the separation portion 49. The separated sheet P is guided to the separation claw 52 and guided to the second discharge path 51 from the sheet carry-out port 48. At this time, the switching flapper 54 is disposed at a discharge position indicated by a solid line. The sheet P guided to the second discharge path 51 is conveyed downstream by the conveyance roller pairs 53, 55, and 56, and is discharged onto the discharge tray 58 by the discharge roller pair 57.

  Here, when printing is performed also on the back surface of the sheet P on which printing has been completed on the front surface, the sheet re-conveying unit 60 disposed on the downstream side of the switching flapper 54 is used. In the vicinity of the switching flapper 54, the sheet re-conveying unit 60 branches from the second paper discharge path 51 and reaches the above-described sheet feeding unit 16, and a re-conveying roller disposed in the middle of the re-conveying path 61. A pair 62. When printing is also performed on the back surface of the sheet P, the sheet P separated from the rotary drum 13 is first transported along the second discharge path 51 by the transport roller pairs 53, 55, and 56. When the trailing edge of the sheet P passes through the switching flapper 54, the conveying roller pair 53, 55, 56 is stopped, and the switching flapper 54 is switched to the re-conveying position indicated by the dotted line. In this state, the transport roller pairs 55 and 56 are rotated in reverse. As a result, the sheet P is guided to the re-conveying path 61 in a state where the front and back sides are reversed, and is again supplied to the sheet conveying unit 16 by the re-conveying roller pair 62. After that, the sheet P is carried and printed on the conveying belt 27 in the same manner as on the front surface, and after the ink is dried by the sheet drying unit 12, the sheet P is passed through the second discharge path 51 on the discharge tray 58. To be discharged.

  The entire inkjet recording apparatus 1 having the above-described configuration operates as follows. The operation and timing of each member (each component) constituting the inkjet recording apparatus 1, for example, the conveyance timing of the sheet P by each roller pair, the conveyance belt 28, the switching timing of the separation claw 52 and the switching flapper 54, The timing of rotation of the rotary drum 13 and the suction fan 40, the timing of ink discharge from the nozzles of the inkjet heads 30 to 33, and the like are appropriately controlled by the control unit 29.

  When a printing start signal is input to the control means 29, in the sheet drying unit 12, the rotary drum 13 rotates, the suction fan 40 starts, the heater 15 is turned on, and the rotary drum 13 is heated. On the other hand, the sheet P is supplied from the sheet feeding unit 16 to the sheet conveying unit 10, is carried on the conveying belt 27, and is conveyed in the direction of the arrow R <b> 27. On the sheet P, ink is ejected from the ink jet heads 30 to 33 of the respective colors based on image information, and four-color full color printing is performed. The printed sheet P is separated from the conveyance belt 27 and supplied to the sheet drying unit 12 through the first discharge path 35. The supplied sheet P is adsorbed on the outer peripheral surface of the rotating drum 13 in order from the leading end side in the adsorbing portion 47. As the rotary drum 13 rotates, the sheet P is directly heated by these heaters 15 when passing through the vicinity of the five heaters 15, and the ink is dried. When the drying is finished, the separation claw 52 is disposed at the separation position indicated by the solid line, and further, when the leading end of the sheet P attracted to the outer peripheral surface of the rotary drum 13 hits the non-sucking portion A, the leading end of the sheet P rises The tip of the separation claw is inserted here. As a result, the sheet P is separated from the outer peripheral surface of the rotary drum 13 at the separation unit 49. The separated sheet P is discharged onto the discharge tray 58 through the second discharge path 51.

  According to the present embodiment, the sheet P that has been printed with ink is attracted to the outer peripheral surface of the rotary drum 13 that has already been heated in the sheet drying unit 12, the surface side is directly heated by the heater 15, and suction is further performed. Since the air flow by the fan is generated so as to penetrate from the front surface to the back surface side of the sheet P, the ink on the sheet P can be efficiently dried in a short time. In addition, the first paper discharge path 35 through which the sheet P carried into the sheet drying unit 12 passes and the second paper discharge path 51 through which the sheet P carried out from the sheet drying unit 12 pass individually without crossing each other. Therefore, by rotating the conveyor belt 27 and the rotary drum 13 in synchronization, it is possible to prevent a decrease in continuous printing speed due to drying of the sheet P by the sheet drying unit 12, Further, no special control is required when the sheet P is transferred from the transport belt 27 to the rotary drum 13.

  For example, when four-color full-color printing is performed using a large amount of ink, the sheet P once adsorbed to the rotary drum 13 and dried is not separated by the separation claw 52. If the separation claw 52 is disposed at the retracted position indicated by the dotted line, the sheet P is not separated from the outer peripheral surface of the rotary drum 13 and continues to rotate in the attracted state. Can be dried. In this case, the rotating drum is rotated twice. However, the rotation of the rotating drum is not limited to two and may be rotated three or more times to further ensure the drying of the ink. If the rotating drum is rotated twice or more with respect to the same sheet P, it is necessary to temporarily stop printing in the printing unit 11, and in this case, the continuous printing speed is reduced. become.

  In the present embodiment, for example, when printing a character image or the like with a low printing rate, the amount of ink attached to the sheet P is small, so that it is not particularly necessary to dry the ink in the sheet drying unit 12. . In such a case, if the heater 15 is turned off, the rotary drum 13 acts as a conveying unit that adsorbs and conveys the printed sheet P to the outer peripheral surface.

  In the present embodiment, the rotating drum 13 made of metal is used as the rotating body, and since the thermal conductivity is good, the rotating drum 13 is easily heated by turning on the heater 15. Therefore, when the sheet P is adsorbed on the outer peripheral surface of the rotary drum 13 and the ink is dried by the heater 15 from the front side, the ink can also be heated from the back side of the sheet P, thereby promoting the drying of the ink. can do.

<Embodiment 2>
FIG. 4 shows an inkjet recording apparatus 2 according to the second embodiment. The figure schematically shows the ink jet recording apparatus 2 as seen from the front side (front side). The ink jet recording apparatus 2 of the present embodiment is different from the ink jet recording apparatus 1 of the first embodiment described above mainly in the sheet drying unit 63, and is otherwise substantially the same. In the present embodiment, the same components and working members as those in the first embodiment described above are denoted by the same reference numerals, and repeated description thereof is omitted as appropriate, and illustration is appropriately omitted.

  For example, the members having the same configuration and operation include the sheet feeding unit 16, the sheet conveying unit 10, the printing unit 11, the separation member 36, the control unit 29, the rotating drum 13, the fixed drum 38, and the suction fan 40 shown in FIG. Etc.

  In the present embodiment, the sheet P is supplied from the sheet feeding unit 16 to the sheet conveyance unit 10 and is carried on the sheet carrying surface 28 of the conveyance belt 27, and is printed as the conveyance belt 27 rotates in the direction of arrow R 27. When passing under the ink jet heads 30 to 33 of each color of the section 11, each color ink is ejected to perform four-color full color printing. The printed sheet P is separated from the transport belt 27 by the separating member 36 and supplied to the first transport path 64. The operation until the printed sheet P is separated from the conveyance belt 27 and supplied to the first discharge path 64 is the same as that in the first embodiment shown in FIG.

  In this embodiment, since the conveyance path of the sheet P attracted to the rotary drum 13 after printing and the conveyance path of the sheet P separated from the rotary drum 13 after ink drying are employed, continuous printing is employed. The speed will drop. On the other hand, the configuration of the first discharge path 64 can be simplified. Hereinafter, these points will be described in detail.

  As shown in FIG. 4, the sheet drying unit 63 is configured so that the inner peripheral surface of the rotary drum 13 faces the outer peripheral surface of the fixed drum 38 with an appropriate gap, as in the first embodiment. Has been placed. Further, three rod-shaped heaters 15 are disposed so as to face the outer peripheral surface of the rotary drum 13. The fixed drum 38, the rotary drum 13, and the heater 15 are covered with a cylindrical cover member 65, and the gap between the outer peripheral surface of the rotary drum 13 and the cover member 65 is as shown in FIG. In the front view, a substantially annular drying space R is formed. In the present embodiment, the drying space R is such that the gap between the outer peripheral surface of the rotary drum 13 and the cover member 65 is wide in the vicinity of a separation claw 66 described later, and the separation claw is arranged along the rotation direction of the rotary drum 13. The farther away from 66, the narrower it becomes. A duct 67 is disposed slightly downstream of the separation claw 66 along the rotation direction of the rotary drum 13. The duct 67 is for discharging the heated air in the drying space R, and is configured to discharge air toward the side opposite to the side where the inkjet heads 30 to 33 are disposed. ing.

  The sheet drying unit 63 is disposed so as to be adjacent to the first discharge path 64, and the drying space R is a sheet carry-in port 68 at a position branched from the first discharge path 64. A portion that is located upstream and joins becomes the sheet carry-out port 70. A separation claw 71 is disposed in the vicinity of the sheet carry-in port 68. The separation claw 71 is switched by the control means between a discharge position indicated by a solid line in FIG. 4 and a drying position indicated by a dotted line. In the present embodiment, the non-adsorption portion A of the fixed drum 38 is disposed near the tip of the separation claw 71 disposed at the discharge position. Further, the vicinity of the tip of the separation claw 71 at the discharge position in the vicinity of the outer peripheral surface of the rotary drum 13 is a separation portion 73 from which the sheet P is separated. When the separation claw 71 is disposed at the discharge position, it closes the sheet carry-in port 68 of the drying space R, guides the sheet P to the downstream side of the first discharge path 64, and is disposed at the drying position. In this case, the downstream side of the first discharge path 64 is closed, and the sheet P is guided to the drying space R.

  The entire inkjet recording apparatus 2 configured as described above operates as follows when the ink on the sheet P is dried. It should be noted that the operation and timing of each member (component) constituting the inkjet recording apparatus 2, for example, the conveyance timing of the sheet P by each roller pair, the conveyance belt 27, the switching timing of the separation claw 71, the rotary drum 13, The rotation timing of the suction fan 40, the ejection timing of ink from the nozzles of the inkjet heads 30 to 33, and the like are appropriately controlled by the control unit 29.

  When a print start signal is input to the control unit 29, in the sheet drying unit 63, the rotary drum 13 rotates, the suction fan 40 starts, the heater 15 is turned on, and the rotary drum 13 is heated. Further, the separation claw 71 is disposed at a drying position indicated by a dotted line. On the other hand, the sheet P is supplied from the sheet feeding unit 16 to the sheet conveying unit 10, is carried on the conveying belt 27, and is conveyed in the direction of the arrow R <b> 27. On the sheet P, ink is ejected from the ink jet heads 30 to 33 of the respective colors based on image information, and four-color full color printing is performed. The printed sheet P is separated from the conveyance belt 27 and is adsorbed to the outer peripheral surface of the rotary drum 13 in order from the leading end side at the adsorbing portion 72 in the vicinity of the sheet discharge port 70, and the rotation of the rotary drum 13 in the direction of arrow R13. Along with this, it rotates in the same direction. When the leading end of the adsorbed sheet P hits the non-adsorbing portion A, the leading end is lifted from the outer peripheral surface of the rotary drum 13, but the separation claw 71 is disposed at the dry position. Since it is adsorbed, it rotates while adsorbed on the outer peripheral surface of the rotary drum 13. Then, when passing near the heater 15, the ink is dried by the radiant heat. The sheet P from which the ink has been dried exits from the sheet carry-out port 70 by the further rotation of the rotary drum 13 and passes through the suction unit 72. The control means 29 arranges the separation claw 71 at the discharge position indicated by the solid line before the leading edge of the sheet P reaches the non-adsorption portion A. When the leading edge of the sheet P reaches the non-adsorbing portion A, it floats up from the outer peripheral surface of the rotating drum 13, and the leading end of the separation claw 71 is inserted between the leading end of the sheet P and the outer peripheral surface of the rotating drum 13. As a result, the sheet P is separated from the outer peripheral surface of the rotary drum 13 in order from the leading end side in the separation unit 73 and conveyed to the downstream side of the first discharge path 64. The sheet P conveyed downstream is discharged onto the paper discharge tray 58 by the discharge roller pair 57.

  The case where printing is performed on one sheet P and ink is dried has been described above as an example. As described above, in the present embodiment, the sheet P after printing crosses the conveyance path to reach the suction unit 72 and the conveyance path to which the sheet P reaches the separation unit after ink drying. In other words, the portion from the suction portion 72 to the separation portion 73 on the outer peripheral surface of the rotary drum 13 uses the sheet P from which ink is to be dried and the sheet P from which ink has been dried. For this reason, adsorption | suction of the sheet | seat P with respect to the outer peripheral surface of the rotating drum 13 and isolation | separation of the sheet | seat P from an outer peripheral surface cannot be performed in parallel, for example, adsorption | suction and separation are performed alternately. Therefore, the continuous printing speed is reduced when printing is continuously performed on a plurality of sheets P (during continuous printing). On the other hand, the suction part 72 and the separation part 73 can be provided in the first discharge bus 64, and the configuration of the first discharge path 64 can be simplified. Further, when it is not necessary to dry the ink after printing, unlike the case of the first embodiment, it is not necessary to operate the sheet drying unit 63. That is, by stopping the rotary drum 13 and the suction fan 40 and disposing the separation claw 71 at the discharge position indicated by the solid line, the outer peripheral surface of the rotary drum 13 is substantially between the suction portion 72 and the separation portion 73. The positioned portion acts as a guide member that guides the back side of the sheet P separated from the conveyance belt 27 after printing, so that the sheet P after printing can be discharged without causing the ink drying unit 63 to operate unnecessarily. 58 can be discharged.

  Also in the present embodiment, when the ink on the sheet P cannot be sufficiently dried by one rotation of the rotating drum 13, the rotating drum 13 is in a state where the sheet P is adsorbed to the outer peripheral surface of the rotating drum 13. The ink can be reliably dried by rotating the ink twice or more. However, in this case, the continuous printing speed is reduced.

<Embodiment 3>
FIG. 5 shows an inkjet recording apparatus 3 according to the third embodiment. The figure schematically shows the ink jet recording apparatus 3 as seen from the front side (front side). In the first and second embodiments, the case where the rotating body is the drum-shaped rotating drum 13 has been described. In the present embodiment, instead of this, a belt-like rotating belt 75 is employed as the rotating body.

  As shown in FIG. 5, the sheet drying unit 74 disposed on the downstream side of the conveyance belt 27 of the sheet conveyance unit 10 includes a rotating belt 75. The rotating belt 75 is stretched between the downstream driving roller 76 and the upstream driven roller 77, and rotates in the arrow R75 direction by the rotation of the driving roller 76 in the arrow direction. The rotating belt 75 has a large number of through holes (not shown) penetrating the belt itself in the front and back direction. A box-shaped duct 78 is disposed inside the conveyor belt 27. The duct 78 has a sliding surface 80 formed on the upper surface thereof, on which the back surface of the rotating belt 75 is rubbed, and the sliding surface 80 has a large number of through holes (not shown). A suction fan (not shown) is attached to the duct 78. The suction fan discharges the air inside the duct 78 to the outside, thereby making the inside of the duct 78 a negative pressure. Accordingly, air is sucked through the through holes of the sliding surface 80 of the duct 78 and the through holes of the rotating belt 75 so that the sheet P is adsorbed on the surface of the rotating belt 75. The rotating belt 75, the driving roller 76, the driven roller 77, the duct 78, the suction fan, and the plurality of heaters 15 are all disposed inside the cover member 81. The cover member 81 covers the above-described members to prevent the heat of the heater 15 from being transmitted to the ink jet heads 30 to 33. A plurality of rod-like heaters 15 are disposed above the rotating belt 75. Each heater 15 is disposed close to the surface of the rotating belt 75 so as to face the surface of the rotating belt 75, and the longitudinal direction thereof is disposed toward the width direction of the rotating belt 75. The plurality of heaters 15 are arranged and arranged from the upstream side to the downstream side.

  In the inkjet recording apparatus 3 of the present embodiment, the sheet P that has been printed and separated by the separation claw 36 is adsorbed to the surface of the rotating belt 75 by the suction fan in the sheet drying unit 74, and the rotating belt 75 is moved to the arrow R75. As it rotates in the direction, it rotates in the same direction and sequentially passes through the vicinity of the plurality of heaters 15. As a result, the ink on the printed sheet P is dried.

  According to the present embodiment, since the rotating body is constituted by the rotating belt 75, the winding shape of the rotating belt 75 can be freely set unlike the case where the rotating body is formed by a rotating drum. For example, in the example shown in FIG. 5, a portion of the rotating belt 75 that conveys the sheet P to be used for drying ink, that is, the downstream side of the driven roller 77 and the driving roller of the rotating belt 75. The shape of the part located on the upstream side of 76 can be set to be planar. For this reason, unlike the case where the rotating body is a rotating drum, it is not necessary to bend the sheet P, so that it is possible to cope with a thick sheet P well. Moreover, the freedom degree about the shape of the sheet | seat drying part 74 can be raised.

  In the above description, the case where four colors of inkjet heads 30 to 33 having different colors are arranged in the printing unit 11 has been described as an example. However, the present invention is not limited to this, for example, Further, the present invention can be similarly applied to a single black color or one having two color ink jet heads. Further, the configurations of the sheet feeding unit 16, the sheet conveying unit 10, the printing unit 11, and the like are not limited to those illustrated in FIGS. 1, 4, and 5, and other configurations may be employed. It is.

  In the above, the present invention has been described by taking as an example the case of drying the ink on the sheet on which printing has been performed by the printing unit. However, the present invention can also be applied to the case of drying the sheet itself.

It is the schematic diagram which looked at the inkjet recording device of Embodiment 1 from the front side. It is a figure which shows the cross section cut by the plane containing the axis | shaft of the rotating drum of Embodiment 1 and Embodiment 2. FIG. It is a figure which shows the cross section cut by the plane containing the axis | shaft of the fixed drum of Embodiment 1 and Embodiment 2. FIG. It is the schematic diagram which looked at the inkjet recording device of Embodiment 2 from the front side. It is the schematic diagram which looked at the inkjet recording device of Embodiment 3 from the front side.

Explanation of symbols

  1, 2, 3... Inkjet recording apparatus, 10... Sheet conveying section, 11... Printing section, 12... Sheet drying section, 13 .. Rotating drum (rotating body), 14. , 15... Heater (heating element), 27... Transport belt (sheet transport member), 30, 31, 32, 33... Inkjet head, 35... First discharge path, 37, 81. 38 …… Fixed drum (duct member), 40 …… Suction fan, 41 …… Moving suction hole, 45 …… Fixed suction hole, 47 …… Suction part, 49 …… Separation part, 51 …… Second discharge path , 52... Separation claw (separation member), 75... Rotating belt (rotating body), 78... Duct (duct member), A.

Claims (11)

Ink is applied to the printing surface of the sheet from a sheet conveying unit having a sheet conveying member that carries and conveys the sheet on the surface, and a plurality of nozzles aligned in a direction intersecting the conveying direction of the sheet conveyed by the sheet conveying member. In an inkjet recording apparatus comprising: a printing unit having an inkjet head for spraying and printing;
A rotating body that carries and rotates a sheet separated from the sheet conveying member after printing on the outer peripheral surface so that the printing surface faces outward;
Adsorbing means for adsorbing the sheet to the rotating body;
A heating element that is disposed so as to face the outer peripheral surface of the rotating body and that dries the ink on the sheet adsorbed on the rotating body.
An ink jet recording apparatus. Ink is applied to the printing surface of the sheet from a sheet conveying unit having a sheet conveying member that carries and conveys the sheet on the surface, and a plurality of nozzles aligned in a direction intersecting the conveying direction of the sheet conveyed by the sheet conveying member. In an inkjet recording apparatus comprising: a printing unit having an inkjet head for spraying and printing;
A rotating body having a plurality of movable suction holes for adsorbing a sheet separated from the sheet conveying member after printing on the outer peripheral surface using negative pressure of air so that the printing surface faces outward;
A duct member having a stationary suction hole fixedly disposed inside the rotating body;
A heating element that is disposed so as to face the outer peripheral surface of the rotating body and that dries the ink on the sheet adsorbed on the rotating body.
An ink jet recording apparatus. The rotating body has a plurality of movable suction holes that are hollow and penetrated in the front and back direction,
The suction means is a suction device that sucks air onto the outer peripheral surface of the rotating body by sucking air from the back surface side of the rotating body through the movable suction hole.
The inkjet recording apparatus according to claim 1. The suction device is a duct member fixedly arranged inside the rotating body and having a plurality of stationary suction holes in a portion corresponding to the movable suction hole;
A suction fan that sucks air from the inside of the duct member to adsorb a sheet to the outer peripheral surface of the rotating body via the stationary suction hole and the movable suction hole;
The inkjet recording apparatus according to claim 3. A first discharge path serving as a discharge path for a sheet separated from the sheet conveying member after printing;
An adsorbing part that adsorbs a sheet to the rotating body;
A separation part from which the sheet is separated from the rotating body,
The adsorption part and the separation part are provided in the first discharge path,
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. A first discharge path serving as a discharge path for a sheet separated from the sheet conveying member after printing;
An adsorbing part that adsorbs a sheet to the rotating body;
A separation part from which the sheet is separated from the rotating body,
The suction portion is provided in the first discharge path;
The separation part is provided in a second discharge path different from the first discharge path;
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. The duct member has a non-adsorption portion without the stationary suction hole in a portion corresponding to the separation portion,
The separation unit has a separation member for separating the sheet adsorbed on the outer peripheral surface of the rotating body,
The ink jet recording apparatus according to claim 2, wherein the ink jet recording apparatus is provided. A cover member is provided that surrounds the rotating body and the heating element to prevent the heat of the heating element from being transmitted to the inkjet head.
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. For one sheet adsorbed on the rotating body, the rotating body is rotated a plurality of times and dried.
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. The rotating body is a metal cylindrical member.
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. The rotating body is a belt-shaped member;
The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus.

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