JP5309044B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an inkjet recording apparatus that performs recording by ejecting ink onto a paper sheet or the like.

  Inkjet recording apparatuses are applied to image forming apparatuses such as facsimiles, copying machines, and printers. For example, in a line head type ink jet recording apparatus, ink is discharged toward the sheet from each color ink discharge nozzle of the line head having a recording area that is equal to or larger than the sheet width while the sheet is conveyed at high speed by a conveying means such as a conveying belt. By doing so, an image is formed. The line head type ink jet recording apparatus having such a configuration enables high-speed printing as compared with a serial type ink jet recording apparatus in which the recording head reciprocates in the sheet width direction.

  In an ink jet recording apparatus for the purpose of high-speed printing processing, it becomes a problem how to dry a sheet after ink is ejected. When the ink is left to dry naturally on the sheet, the sheet needs to be stocked in the recording apparatus only during the natural drying time. In this case, there is a problem that the apparatus size is increased in order to secure a stock space for a large number of sheets.

  Japanese Patent Laid-Open No. 2004-133867 describes a conveyance unit that sends back a sheet on which an image is recorded by an inkjet recording unit to the upstream side in the conveyance direction, and a non-recording surface of the sheet that is provided on the downstream side in the conveyance direction and is fed back by the conveyance unit. An ink jet recording apparatus including a plurality of holding units that suck and hold and reversely feed a sheet to a recording unit is disclosed. In this recording apparatus, the sheet is held by a plurality of holding units to maintain the high speed of printing while ensuring the drying time.

JP 2006-213480 A

  However, in the method of Patent Document 1, since the drying time is secured by the reversing means, there is a possibility that the drying time cannot be secured sufficiently during single-sided printing. For this reason, there is a possibility that the problem that the discharge roller is contaminated with ink due to insufficient drying even during single-sided printing, which is now occurring at higher printer speeds, may not be sufficiently dealt with.

  Therefore, it is conceivable to take a means for accelerating the drying of the ink by blowing an air flow, particularly hot air, onto the printed sheet on which the ink has been ejected. In this case, a storage unit for storing sheets is provided on the downstream side of the recording unit, and a method in which hot air is blown from the side of the sheet bundle while sequentially stacking the printed sheets into a sheet bundle in this storage unit is adopted. can do. Thereby, warm air circulates between the sheets, and the ink on the sheets can be dried quickly.

  In the case of providing such a warm air blowing type drying apparatus, as a new problem, the difficulty of stably and sequentially stacking the printed sheets in the sheet storage unit is raised. That is, since warm air (air flow) is blown against the sheet bundle stocked in the accommodating portion, there is a concern that the stable stacking of sheets is hindered by the air flow.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet recording apparatus that can promote drying of a sheet after printing and can stably convey the sheet.

An inkjet recording apparatus according to an aspect of the present invention includes a recording unit that ejects ink on a sheet, and a sheet after the ink is ejected, sequentially stacked in an upward direction, and stocked in a sheet bundle shape. A drying apparatus that performs a drying process on the sheet, and a conveying unit that conveys the sheet to the drying apparatus via the recording unit, and the drying apparatus stocks the sheet to be loaded into a sheet bundle. And a first air blowing unit that blows an air flow from a side surface direction of the stocked sheet bundle, and at least a sheet is blown from the upper surface direction of the sheet bundle when the sheet is carried into the drying device. viewed including a second blower, wherein the conveying means includes a guide for guiding the sheet to the receiving portion at an upper surface, the first blower is disposed above the guide, the Along the carrying direction to the receiving portion of the over bets, characterized in that it comprises a blower means for blowing air from the carrying-direction upstream side in the side surface direction of the stocked the sheet bundle into said receiving portion (claim 1) .

  According to this configuration, the drying apparatus includes not only the first air blowing unit that blows the air flow from the side surface direction of the sheet bundle, but also the second air blowing unit that blows the air flow from the upper surface direction of the sheet bundle. The second air blowing unit is arranged from the upper surface direction of the sheet bundle when the sheets are carried into the drying device, that is, when the sheets are stacked on the sheet bundle on which the air flow is blown from the side surface direction by the first air blowing unit. Spray an air stream. Thereby, since the sheet which is likely to be swollen or blown off from the side surface direction by the air flow from the upper surface direction can be regulated, the sheet can be stably guided to a predetermined stock position.

  The said structure WHEREIN: It is desirable that the airflow which the said 1st ventilation part and the said 2nd ventilation part blow is warm air (Claim 2). According to this configuration, drying of the sheet is further promoted.

  In the above configuration, the apparatus further includes a sensor that detects that the sheet that has passed through the recording unit has been carried into the drying device, and a control unit that controls a blowing operation of the air flow by the second air blowing unit, Preferably, the control unit starts the air flow spraying operation by the second air blowing unit after the sensor detects the loading of the sheet, continues the spraying for a predetermined time, and then stops the spraying operation. (Claim 3).

  According to this configuration, by providing the sensor, for example, the blowing of the air flow from the second air blowing unit is started at the timing when the stacking of one sheet on the sheet bundle is started, and the stacking is completed at the timing. It can be controlled so that the blowing of airflow is stopped. Thereby, at the time of carrying in to the drying apparatus of a sheet | seat, it can be made to perform the blowing of the airflow from a 2nd ventilation part in the period which is most susceptible to the airflow from the side surface direction.

In the above configuration, the first blower blows an air flow from the upstream side in the carry-in direction toward the side surface of the sheet bundle below the guide in order to pass the air flow between the sheets of the sheet bundle. It is desirable to include a separating air blowing section (claim 4). According to this configuration, the air flow can be favorably distributed between the sheets of the sheet bundle, and the drying effect of the sheet after printing can be improved.

In this case, the conveying means comprises a conveyor belt endless conveying the sheet toward the downstream side from the upstream side of the recording portion, and the guide for guiding the sheet to the receiving portion from the downstream end of the conveying belt , loading position of the seat by the guide than the bottom surface of the accommodating portion is set to a position higher by a predetermined height, the second blower unit, the air in the vicinity of the inlet of the receiving portion the sheet is carried by the guide It is desirable to spray a flow (Claim 5).

  According to this configuration, the air flow is blown from the lower side of the guide toward the back surface side of the sheet to be carried in and the side surface of the sheet bundle by the separating air blowing unit, so that the sheets of the sheet bundle can be further increased. It becomes easy to distribute an air flow between them. On the other hand, when such an air flow spraying mode is adopted, the carried-in sheet tends to be swept up or blown away by the air flow generated by the separating air blowing unit, and is supplied to the sheet storage unit. Conveyance is likely to be disturbed. However, since the second air blowing unit blows an air flow from the upper surface direction of the sheet bundle in the vicinity of the entrance of the storage unit into which the sheet is carried, the conveyance disturbance is effectively suppressed.

  According to the present invention, drying of a sheet after printing can be promoted by a drying device including the first air blowing unit, and the sheet is stabilized to a predetermined stock position by blowing an air flow from above with the second air blowing unit. Can be guided. Therefore, it is possible to provide an ink jet recording apparatus that can quickly dry and discharge a sheet without causing sheet conveyance disturbance.

1 is a front sectional view showing an overall schematic structure of an ink jet printer according to an embodiment of the present invention. It is a perspective view which shows the conveyance unit and drying apparatus which are used for the said inkjet printer. It is front sectional drawing which shows schematic structure of the said conveyance unit and drying apparatus. It is a perspective view of the said drying apparatus. FIG. 5 is a perspective view showing a state where the upper cover is removed in the drying apparatus shown in FIG. 4. It is a perspective view which shows the state cut | disconnected by the VI-VI line of FIG. It is sectional drawing for demonstrating the stock state and carrying-in state of the sheet | seat in the said drying apparatus. It is a perspective view which shows the ventilation fan with a shutter. It is a perspective view which shows the sheet | seat discharge part used for the drying apparatus of this embodiment. It is sectional drawing of the said sheet | seat discharge part. 1 is a block diagram illustrating a configuration of an ink jet printer. It is a time chart which shows control of hot air blowing from the upper surface side of a sheet bundle. It is a schematic diagram which shows the warm air blowing operation | movement from the upper surface side of a sheet | seat bundle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front sectional view showing a schematic structure of an ink jet printer 1 (ink jet recording apparatus) according to an embodiment of the present invention. FIG. 2 is a perspective view showing a transport unit 10 and a drying device 30 used in the printer 1. FIG. 3 is a front sectional view of the transport unit 10 and the drying device 30.

  The printer 1 includes a paper feed cassette 3, a recording unit 7, a transport unit 10 (transport unit), a drying device 30, a sheet discharge unit 50, and a discharge tray 65. The general operation of the printer 1 will be described. Sheets P are sequentially fed out from the paper feed cassette 3 and conveyed by the conveyance unit 10, and printing processing (ink ejection) is performed by the recording unit 7. Thereafter, the sheet P is carried into the drying device 30, and warm air is blown in a state where the sheet P is stocked in a sheet bundle shape, and an ink drying process is performed. Then, the sheet P positioned at the bottom surface of the sheet bundle is sequentially fed from the drying device 30 by the sheet discharge unit 50 and discharged to the discharge tray 65.

  The paper feed cassette 3 accommodates a bundle of sheets P printed by the recording unit 7. The sheet P is, for example, a plain paper sheet, a hard paper sheet, an OHP sheet, a cloth sheet, or the like. The sheet P in the paper feed cassette 3 is conveyed toward the recording unit 7 (conveyance unit 10) for printing processing. For this conveyance, a paper feed roller 4, a sheet conveyance path 5 and a registration roller 6 are arranged between the conveyance unit 10 and the paper feed cassette 3.

  The paper feed roller 4 is disposed above the downstream portion of the paper feed cassette 3 in the sheet conveyance direction, and is in contact with the uppermost sheet P of the sheet bundle. The sheet P is sent toward the upper right of the sheet cassette 3 in FIG. Thereafter, the sheet P reaches the registration roller 6 through the sheet conveyance path 5 and is temporarily stopped. The registration roller 6 corrects the oblique feeding of the sheet P and sends the sheet P toward the transport unit 10 again. A detection member (not shown) at the front end of the sheet is disposed in the sheet conveyance path 5 between the recording unit 7 and the registration roller 6. At the timing when the leading edge of the sheet P is detected by the detection member, the recording unit 7 executes the ink ejection operation. The sheet conveyance path 5 is provided with a required number of conveyance roller pairs for conveying the sheet P.

  The conveyance unit 10 includes a printing drive roller 12, a printing driven roller 13, a printing tension roller 14, and an endless printing conveyance belt 11 wound around these rollers 12, 13, and 14. The printing conveyance belt 11 rotates in the counterclockwise direction in FIG. 1 by the rotation driving of the printing driving roller 12. An auxiliary driven roller 15 is disposed above the printing driven roller 13 and forms a nip pair with the printing driven roller 13. The printing drive roller 12 is driven by a transport motor 74 (see FIG. 11).

  The sheet P sent out by the registration roller 6 is placed on the upper surface of the printing transport belt 11 and is transported from the right side to the left side in FIG. Note that a belt in which both ends thereof are overlapped and joined to each other to form an endless shape, a seamless belt (seamless), or the like is preferably used for the printing conveyance belt 11.

  A printing air suction fan (not shown) is provided inside the transport unit 10 at a location facing the recording unit 7. By the operation of the printing air suction fan, air can be sucked downward from the upper surface of the transport unit 10. The printing conveyor belt 11 is provided with a number of air suction holes (not shown). As a result, the transport unit 10 can transport the sheet P while adsorbing the sheet P to the upper surface of the print transport belt 11 and bringing it into close contact.

  The printer 1 receives image data signals such as characters, graphics, and patterns from an external computer (not shown) in a control unit 20 described later. Information on the image data is transmitted to a recording unit 7 having a recording head 8. The recording unit 7 is disposed above the transport unit 10 so as to face the transport unit 10. Specifically, a minute gap (for example, 1 mm) is provided between the printing surface on which the tip of the ink discharge nozzle (not shown) of the recording head 8 is arranged and the sheet conveyance surface that is the upper surface of the printing conveyance belt 11. The recording unit 7 is disposed on the transport unit 10.

  The recording unit 7 ejects ink on the sheet P for printing, and includes three recording heads 8 corresponding to the respective colors for a total of 12 colors (not shown). Each of the recording heads 8 extends in the sheet width direction perpendicular to the sheet conveyance direction, and, as shown in FIG. 1, along the circumferential direction of the printing conveyance belt 11, from the upstream side to the downstream side in the circumferential direction. They are arranged side by side. The recording heads 8 corresponding to the four colors are a black recording head 8K, a cyan recording head 8C, a magenta recording head 8M, and a yellow recording head 8Y in this order from the upstream side.

  Corresponding to the recording heads 8 for the respective colors, four ink tanks 26 (see FIG. 11) (not shown) are provided below the transport unit 10. The ink of each color is supplied from the ink tank 26 to the recording head 8 by a supply tube (not shown). In the following description, the identification symbols “K”, “C”, “M”, and “Y” are omitted unless particularly limited.

  As the ink ejection method of the recording head 8, for example, a piezo method that pushes out ink using a piezo element (not shown), a thermal ink jet method that generates air bubbles by a heating element, and ejects ink by applying pressure. Various methods can be applied.

  Each recording head 8 of the recording unit 7 discharges ink toward the sheet P which is placed on the surface of the printing conveyance belt 11 and is being conveyed, corresponding to the image data information received from the external computer. As the printing transport belt 11 circulates, ink of each color is sequentially ejected from each recording head 8 at a predetermined timing, whereby four sheets of black, cyan, magenta, and yellow are formed on the sheet P on the surface of the printing transport belt 11. A color ink image in which color inks are superimposed is formed.

  If necessary, a heating blower or the like can be provided above the four-color recording head 8. In addition, a preheating heating device or the like can be provided on the downstream side of the paper feed cassette 3.

  On the other hand, an elevating device (not shown) for the transport unit 10 is provided below the transport unit 10. The elevating device attaches a cap (not shown) to the recording head 8 or performs a jam process that occurs on the printing conveying belt 11 in order to prevent drying or clogging of the ink discharge nozzles of each recording head 8. The transport unit 10 is moved up and down.

  The cap is moved up and down and horizontally moved by a vertical movement mechanism and a horizontal movement mechanism (not shown) using a work space formed by lowering the transport unit 10. The cap is moved up and down by the vertical movement mechanism and is attached to and detached from the recording head 8. Further, after being detached from the recording head 8, the cap is horizontally moved by a horizontal movement mechanism, and is moved between a position where it can be attached to and detached from the recording head 8 and a standby position.

  In order to prevent the recording head 8 from drying and clogging, the recording unit 7 starts recording after stopping for a long period of time. From the nozzles of the head 8, ink with increased viscosity in the nozzles is ejected. At this time, the cap is brought close to the recording head 8 with a minute distance, and the ink is ejected into the cap.

  The drying device 30 is disposed on the downstream side (left side in the drawing) of the transport unit 10 in the sheet transport direction. The sheet P that has passed through the recording unit 7 is carried into the drying device 30, and the ink discharged onto the sheet P is dried by the drying device 30. After the sheet P is dried by the drying device 30, the sheet P is fed from the drying device 30 by the sheet discharge unit 50, and discharged to the discharge tray 65 through the conveyance path 61. The discharge tray 65 is a tray on which the sheets P that have been printed and dried are stacked, and the user takes out the sheets P from the discharge tray 65.

  The drying device 30 includes an accommodating part 31, a carry-in guide part (guide part) 33, a separation air blowing part (a part of the first air blowing part) 35, a regulating air blowing part (second air blowing part) 36, and first to fifth drying. Air blower (a part of the first air blower) 371, 372, 373, 374, 375, the exhaust part 45 and the sheet discharge part 50. The drying device 30 is a device that performs a drying process on the sheets P while sequentially stacking the sheets P after the ink is discharged and stocking them in a sheet bundle shape.

  4 is a perspective view of the drying device 30, FIG. 5 is a perspective view showing the drying device 30 with the upper cover removed, and FIG. 6 is a perspective view showing a state cut along line VI-VI in FIG. FIG. 7 is a cross-sectional view for explaining the stock state and the carry-in state of the sheet P in the drying device 30. In these drawings, parts common to those in FIGS. 1 to 3 are denoted by common reference numerals and description thereof is omitted. In FIG. 5, a solid line arrow schematically shows an air flow sent into the housing portion 31, and a broken line schematically shows an air flow path discharged from the housing portion 31.

  The accommodating portion 31 is formed of a substantially rectangular parallelepiped box-shaped member, and the sheet P on which ink is ejected is carried. The accommodating portion 31 has a volume that allows the sheets P to be sequentially stacked upward from the bottom surface side of the accommodating portion 31 and stocked in a sheet bundle shape having a predetermined thickness. The accommodating part 31 is sealed except for the connection part with the carrying-in guide part 33, the isolation | separation ventilation part 35, the control ventilation part 36, and the drying ventilation parts 371-375. Further, as shown in FIGS. 5 and 6, the accommodating portion 31 is provided with a cursor 38 for restricting movement of the sheet P in the conveyance direction.

  The cursor 38 is disposed so as to be able to regulate the movement in the loading direction of the sheet P loaded according to the size of the sheet P. FIG. 5 shows a state in which the movement of the A3 vertical paper (see FIG. 2) is restricted by being fitted into a predetermined positioning hole (not shown) provided on the bottom surface of the accommodating portion 31. Alternatively, the movement of the A4 vertical paper can be restricted by fitting the cursor 38 into the positioning hole 39, for example.

  The carry-in guide unit 33 (a part of the conveyance unit) is disposed between the conveyance unit 10 and the upstream end of the storage unit 31 in the sheet conveyance direction, and the sheet P is transferred from the downstream end of the conveyance belt 11 to the storage unit 31. To guide you. The height position at the downstream end in the sheet conveyance direction of the carry-in guide unit 33, that is, the carry-in height position of the sheet P is set to a position higher than the bottom surface of the storage unit 31 by a predetermined height. Accordingly, the sheets P are sequentially stacked upward from the bottom surface of the storage unit 31, and a sheet bundle having a predetermined thickness is formed in the storage unit 31. In other words, the carry-in height position of the sheet P by the carry-in guide unit 33 is determined according to the planned thickness of the sheet bundle formed in the storage unit 31.

  The separation blower 35 is a blower that is disposed in a space below the carry-in guide 33 and can blow air over the entire width direction sheet passing region of the storage unit 31. As shown in FIG. 7, the separating air blowing unit 35 directs the warm air (air flow) from the upstream side in the carrying direction of the sheet P to the drying device 30 toward the side surface of the sheet bundle PA accommodated in the accommodating unit 31. Spray. Thereby, separation and drying efficiency of sheet P can be improved.

  As schematically shown in FIG. 5, a blower fan 41 and a heater device 43 are provided in order to blow out warm air from the separation blower 35. The blower fan 41 has a fan that is rotationally driven, and generates an air flow. The heater device 43 includes a ventilation duct and a sheathed heater arranged in the ventilation duct, and heats the air passing through the ventilation duct to generate hot air of about 100 ° C., for example. The first duct 42 is connected between the blower fan 41 and the air inlet 351 of the separation blower 35. The blower fan 41 and the heater device 43 are connected by a second duct 44. Further, the heater device 43 and the exhaust part 45 are connected by a third duct 46. These ducts 42, 44, 46 form an air flow circulation path with the upstream side and the downstream side of the accommodating portion 31 as starting points and ending points, respectively.

  Due to the operation of the blower fan 41 and the heater device 43, the warm air is supplied to the inlet portion 351 of the separation blower portion 35. Thereafter, the warm air is blown out from the separating fan 35 toward the housing 31. As shown in FIG. 6, the connecting portion of the separating air blowing portion 35 to the accommodating portion 31 is formed of a plate-like member 352 provided with a large number of small holes, and the air flow is dispersed to the inside of the accommodating portion 31. To be sent to.

  The airflow blown out from the separation blower 35 is an airflow in a direction substantially parallel (substantially horizontal) to the bottom surface of the housing 31 (see FIG. 7). When the sheets P are sequentially loaded into the storage unit 31, the air flow passes between the sheet bundles PA stocked in the storage unit 31, and the sheet bundle PA resists the gravity acting on the sheets P. The air volume is set so that a gap is formed between the sheets P.

  Thereby, a gap is formed between the sheets P of the sheet bundle PA due to the passage of the air flow. As a result, the sheets P are brought into close contact with each other before the ink is dried, and the ink of one sheet P can be prevented from adhering to the other sheet P, thereby preventing the occurrence of problems such as deterioration in image quality. it can. In particular, the height position of the downstream end 33E in the sheet conveyance direction of the carry-in guide portion 33 is set near the upper portion in the vertical direction of the storage portion 31, and the air flow is sent out from the back side of the carry-in guide portion 33. An air flow is effectively supplied between the uppermost sheet P of the bundle PA and the next sheet P that is carried onto the sheet P, thereby preventing contact between the sheets P that have not passed much time since printing. can do. Furthermore, since warm air passes between the sheets P of the sheet bundle PA, drying of the ink discharged onto the sheets P is promoted.

  As described above, the air flow between the sheets P is improved by blowing the air flow toward the side surface of the sheet bundle PA by the separating air blowing unit 35. On the other hand, when such an air flow spraying mode is adopted, the sheet P to be carried in tends to be swollen or blown away by the air flow generated by the separating air blowing unit 35, and the sheet P accommodating portion Conveyance to 31 is likely to be disturbed. In the present embodiment, in order to prevent such a problem, a regulation blower 36 that blows an air flow from the upper surface direction of the sheet bundle PA toward the sheet bundle PA is provided.

  The regulated air blower 36 is attached to the upper cover 311 of the drying device 30 located on the top surface of the housing 31. The arrangement position is an upper part near the entrance of the storage unit 31 into which the sheet P is carried by the carry-in guide unit 33. With such an arrangement, when the sheet P is carried into the drying device 30, that is, the regulated air blowing unit 36, that is, the sheet P is placed on the sheet bundle PA on which the air flow is blown from the side by the separating air blowing unit 35. When the sheets are stacked, it is possible to blow an air flow from the upper surface direction of the sheet bundle PA. As a result, the sheet P that tends to be blown up or blown away by the air flow from the separating blower 35 can be regulated by the air flow from the upper direction to the lower direction, so that the sheet P can be controlled at a predetermined stock position ( It is possible to stably lead to the uppermost surface of the sheet bundle PA.

  As shown in FIG. 1, a blower fan 81 is provided corresponding to the regulated blower 36. A heater 81H is disposed at the air supply port of the blower fan 81, and the airflow blown out from the blower fan 81 is heated. Therefore, warm air is supplied to the regulated air blower 36, and the regulated air blower 36 blows this warm air toward the upper surface of the sheet bundle PA. For this reason, the air flow blown out from the restriction blower 36 contributes not only to the restriction of the sheet P described above but also to the drying of the sheet P.

  A shutter 82 is provided at the entrance of the restricted air blower 36 to block the supply of airflow from the blower fan 81 to the restricted air blower 36. FIG. 8 is a perspective view showing details of the shutter 82. The shutter 82 has an opening 821, and when the opening 821 and the air supply port 811 of the blower fan 81 coincide with each other, warm air is supplied to the regulated blower 36. The shutter 82 is fixed to a frame plate 822 that can reciprocate in the direction of an arrow 823 in the drawing. The reciprocating movement of the frame plate 822 is performed by the driving unit 83 shown in FIG. The drive unit 83 includes, for example, a cam device and a motor. The drive unit 83 includes an open position for opening the air supply port 811 of the blower fan 81 and a closed position for closing the air supply port 811 via the frame plate 822. Move between. The opening / closing operation of the shutter 82 by the driving unit 83 is controlled by a shutter control unit 84 (control means).

  As shown in FIG. 7, a conveyance detection sensor (sensor) 331 is disposed at the upstream end of the carry-in guide unit 33 in the sheet conveyance direction. The conveyance detection sensor 331 is a reflection-type optical sensor, and is arranged to detect that the sheet P that has passed through the recording unit 7 has been carried into the drying device 30. As will be described in detail later with reference to FIGS. 12 and 13, the shutter control unit 84 performs opening / closing control of the shutter 82 based on the sheet detection timing by the conveyance detection sensor 331.

  The first to fifth drying blowers 371 to 375 are connected to a pipe (not shown) branched from the first duct 42 (FIG. 5) disposed between the blower fan 41 and the separation blower 35. . Similarly to the separation blower 35, the air flow (warm air) generated by the blower fan 41 and heated by the heater device 43 is supplied to each of the first to fifth drying blowers 371 to 375. (Supply status is indicated by solid arrows in the figure). The first to fifth drying air blowing units 371 to 375 are arranged to blow warm air from the side surface direction of the housing unit 31 toward the side surface of the sheet bundle PA. These warm airs also circulate between the sheets P of the sheet bundle PA.

  The first drying blower 371 is provided near the upstream end of the carry-in guide unit 33 in the sheet conveyance direction, and sends an air flow along the carry-in guide unit 33 from the upstream side in the conveyance direction to the side surface direction of the sheet bundle PA. (See FIG. 7). The hot air outlet of the first drying air blower 371 has a slit shape having substantially the same length as the width of the housing 31, and the hot air blown out from the air blower not only dries the sheet P but also the sheet P It plays the role of assisting the conveyance to the drying device 30.

  The second and third drying air blowing sections 372 and 373 are attached to one side wall in the width direction of the housing section 31. The fourth and fifth drying air blowing sections 374 and 375 are attached to the other side wall in the width direction of the housing section 31 so as to face the second and third drying air blowing sections 372 and 373. With these second to fifth drying air blowing units 372 to 375, hot air can be blown from the outside in the width direction to the sheet bundle PA stocked in the storage unit 31.

  A plate-like member provided with a large number of small holes is arranged on the surface of the second to fifth drying air blowing units 372 to 375 facing the housing unit 31, and hot air is dispersed from these small holes. It is sent into the accommodating part 31. Thereby, the drying efficiency of the sheet | seat P can be improved. In addition, separation between the sheets P of the sheet bundle PA is also promoted by the air flow from the second to fifth drying air blowing units 372 to 375. In other embodiments, the second to fifth drying air blowing units 372 to 375 are configured to be movable in the width direction of the storage unit 31, and the width of the sheet P depends on the size of the sheet P to be carried in. It can also be used as a cursor for restricting the movement of directions.

  As shown in FIG. 5, the exhaust part 45 is arranged at the downstream end of the accommodating part 31 in the carry-in direction. By the exhaust part 45, the air sent into the accommodating part 31 from the ventilation part 35 for separation and the ventilation parts 371-375 for the 1st-5th drying can be discharged | emitted (broken line arrow). Thereby, since the air inside the accommodating part 31 is always replaced | exchanged, the drying efficiency of the sheet | seat P improves.

  Further, the outlet portion 451 of the exhaust portion 45 is connected to one end of the third duct 44. That is, the outlet part 451 of the exhaust part 45 is connected to the separation air blowing part 35 and the first to fifth drying air blowing parts 371 to 375 via the first to third ducts 42 to 44. Thereby, the airflow discharged | emitted from the exhaust part 45 can be circulated to the ventilation part 35 for separation, and the ventilation parts 371-375 for 1st-5th drying, and can be reused. Therefore, energy efficiency can be improved by effectively using an air flow having residual heat, and drying efficiency can be increased.

  As shown in FIG. 5, the accommodating portion 31 is provided with a temperature / humidity sensor 71 for measuring the environmental temperature and humidity. The detection result of the temperature / humidity sensor 71 is transmitted to the control unit 20 described later. Based on the temperature and humidity detection results by the temperature and humidity sensor 71, the drying time of the sheet bundle PA is set.

  As shown in FIGS. 5 and 6, the sheet discharge unit 50 is disposed below the separating air blowing unit 35, and is one of the lowermost sheets of the sheet bundle PA stocked in the storage unit 31. Only the sheet P is discharged from the storage unit 31. FIG. 9A is a perspective view showing only the sheet discharge portion 50 according to the present embodiment, and FIG. 9B is a perspective view showing a state where the discharge conveyance belt 51 is removed in FIG. 9A. FIG. 10 is a front sectional view of the sheet discharge unit 50.

  The sheet discharge unit 50 includes a discharge drive roller 52, a discharge conveyance roller 53, a discharge driven roller 54, a discharge tension roller 55, and a discharge conveyance belt 51 spanned between these rollers. A drive gear 59 is connected to the rotation shaft 52a of the discharge drive roller 52, and the drive gear 59 is connected to a motor (not shown). When a driving force is applied from the motor to the driving gear 59, the discharging conveyor belt 51 rotates clockwise.

  Between the discharge driving roller 52 and the discharge driven roller 54 with the discharge conveyance roller 53 interposed therebetween, a suction box 57 that forms a substantially sealed space with the discharge conveyance belt 51 is provided. The suction box 57 is connected to a discharge air suction fan (not shown), and the air in the suction box 57 is sucked by the operation of the discharge air suction fan.

  As shown in FIG. 9A, the discharge transport belt 51 has a number of holes 51a for air suction. When the discharge air suction fan is operated, the sheet P is attracted to the suction area S (the broken line portion in FIG. 10) on the upper surface of the discharge transport belt 51, and the sheet P can be discharged while closely contacting. Further, the discharge conveying roller 53 is provided with a plurality of annular grooves 53 a in the circumferential direction, and the sheet P can be sufficiently adsorbed on the upper surface of the discharge conveying belt 51 even at the stretched portion by the discharging conveyance roller 53. Can do. As a result, only the lowermost sheet P of the sheet bundle PA can be reliably and sequentially sent out at a predetermined interval. The sheet P sent out by the sheet discharge unit 50 is discharged toward the discharge tray 65 by the discharge roller 63 provided in the conveyance path 61.

  Next, the drying operation of the drying device 30 will be described mainly based on FIG. When the sheet P is carried into the drying device 30 from the transport unit 10, the sheet P is sequentially stacked on the storage unit 31 from below through the carry-in guide unit 33. At this time, the rising of the sheet P is regulated by the air flow from the upper surface direction blown from the regulated air blowing unit 36, so that the sheet P can be stably stacked on the storage unit 31. Here, the blowing of the air flow from the regulated air blowing unit 36 may be performed constantly during the printing operation, or may be performed intermittently in synchronization with the timing when the sheet P is carried into the drying device 30. Alternatively, at least when the sheet P is carried into the drying device 30, it is sufficient that the air flow is blown. In the present embodiment, the regulated air blower 36 performs an intermittent air flow blowing operation. This point will be described later.

  Since the air flow (warm air) is sent from the upstream side in the conveying direction to the accommodating portion 31 from the upstream side in the conveyance direction, and the air flow passes between the sheets P in the sheet bundle PA, the sheets P are in contact with each other. You can avoid it. While maintaining this non-contact state, on the sheet P stocked in the accommodating portion 31 by contacting with the air flow sent from the separation blower 35 and the first to fifth drying blowers 371 to 375 for a predetermined time. The ink is dried. Warm air blown from the regulated air blower 36 also contributes to this drying. After drying, the sheets P are sequentially discharged one by one from the bottom by the sheet discharge unit 50.

  More details are as follows. The printing operation is performed at a predetermined printing speed (printing interval) Ts (sec / sheet) set by the recording unit 7 and the transport unit 10. Further, a predetermined time required for drying the sheet P is defined as a necessary drying time Ta (sec). At this time, after the first sheet P1 is carried into the accommodating portion 31, the second and subsequent sheets P are sequentially carried in at the printing interval Ts.

  For this reason, it is necessary to carry Ta / Ts sheets P into the storage unit 31 from when the sheet P1 is transferred into the storage unit 31 until the sheet P1 is dried. That is, it is necessary to stock the sheets P <b> 1 until a total of {(Ta / Ts) +1} sheets P are carried into the storage unit 31. The number of sheets P necessary for such drying is defined as a dry stock number N (N is an integer).

  First, consider a case where the total number of printed sheets J (J is an integer) set by the user or the like is equal to or larger than the dry stock number N (J ≧ N). In this case, when the first to Nth sheets P <b> 1 to PN are carried into the storage unit 31, since the stock time of the sheet P <b> 1 has elapsed after the necessary drying time Ta, the sheet discharge unit 50 causes the sheet to dry. P1 is discharged from the storage unit 31. Thereafter, if the sheets P2, P3,... Are sequentially discharged every time the printing interval Ts elapses from the discharge of the sheet P1, the stock time of each sheet P has passed the drying required time Ta at the time of discharge. .

  On the other hand, if the printing operation continues after the (N + 1) th sheet, the (N + 1) th sheet PN + 1 is loaded into the storage unit 31 at the printing interval Ts from the loading of the sheet PN. Note that the sheet PN + 1 is carried in after the sheet P1 is discharged and before the sheet P2 is discharged. Further, the N + 2 and N + 3 sheets PN + 2 and PN + 3 to be subsequently printed are carried in, replacing the discharge of the sheets P2 and P3, respectively.

  Thereafter, up to the (N + m) th sheet (m is an integer), the above discharge and carry-in operations are repeated in a state where N sheet bundles PA are always present in the storage unit 31. After the number of sheets P carried into the storage unit 31 reaches the total number of printed sheets J (that is, N + m = J), the N sheets P remaining in the storage unit 31 are sequentially printed at the printing interval Ts. Discharged.

  When the total number of printed sheets J is equal to N (J = N), after the sheet P1 is conveyed from the sheet P1 to the sheet PN, the sheets are sequentially discharged from the sheet P1 at the printing interval Ts. However, since the (N + 1) th and subsequent sheets P are not printed, the sheet P is not carried into the storage unit 31 any more and only the sheets P1 to PN are discharged.

  On the other hand, when the total number of printed sheets J is less than the dry stock number N, even if all the printed sheets P are loaded into the storage unit 31, the time during which the first loaded sheet P1 is stored in the storage unit 31 is dry. The required time Ta is not reached. Therefore, the storage unit 31 waits until the necessary drying time Ta elapses after the sheet P1 is carried in, and after the necessary drying time Ta elapses, the sheet P1 is discharged. Then, following the discharge of the sheet P1, all the sheets P are discharged at the printing interval Ts. At this time, as described above, the stock time of each of the second and subsequent sheets P passes the necessary drying time Ta at the time of discharge.

  The required drying time Ta may be affected by the type of ink, the type of sheet P, and the like. Further, the required drying time Ta is shorter as it becomes easier to dry (high temperature and low humidity) and becomes longer as it becomes difficult to dry (low temperature and high humidity). Moreover, it is influenced by the heating capacity of the heater device 43, the blowing capacity of the blower fan 41, the size of the apparatus, and the like. Furthermore, if the required drying time Ta is increased, the number of dry stocks N is increased, which may increase the size of the apparatus. Therefore, for example, it is desirable to appropriately set the relationship between the environmental conditions and the necessary drying time Ta in consideration of these viewpoints by a preliminary experiment or the like.

  Further, since the printing interval Ts is influenced by the printing capability of the recording unit 7 and the conveyance capability of the conveyance unit 10, for example, the printing interval Ts can be set in consideration of these, and the dry stock number N can be set. . The printing interval Ts is represented by 60 / X when, for example, a predetermined number X (X is an integer) is printed for 60 seconds. The calculation result is used by rounding up the decimal point, for example. it can. Further, the number N of dry stocks set in this way can be set to 20, for example.

FIG. 11 is a block diagram illustrating an electrical configuration of the printer 1. Portions common to FIGS. 1 to 10 are denoted by the same reference numerals, and description thereof is omitted here. The printer 1 includes a control unit 20. An RIP (printer controller) 22, an FPGA (Field Programmable Gate Array) 23, and the like are connected to the control unit 20, and the RIP 22 is an FPG.
It is also connected to A23.

  An ink tank 26, an encoder 28, and recording heads 8K to 8Y are connected to the FPGA 23. An AD converter 72 and a motor control IC 73 are connected to the control unit 20, a temperature / humidity sensor 71 is connected to the AD converter 72, and a conveyance motor 74 is connected to the motor control IC 73. The control unit 20 and the FPGA 23 are connected to the main power supply 69.

  The control unit 20 is composed of, for example, a CPU, and outputs control signals to various control circuits to control the recording operation of the recording unit 7, the transport operation of the transport unit 10, the drying operation of the drying device 30, and the like. Further, the control unit 20 has a function of converting an image signal received via the RIP 22 into image data and transmitting the image signal to the FPGA 23 to execute image processing and processing, and a function of controlling the conveyance speed of the sheet P. ing.

  The control unit 20 can access a RAM (not shown), and the RAM stores parameters relating the environmental conditions and the required drying time Ta, parameters related to the printing interval Ts, and the like. Further, the control unit 20 receives the detection result of the temperature / humidity sensor 71 provided in the drying device 30 via the AD converter 72, and calculates the required drying time Ta based on the parameters stored in the RAM or the like. In addition, it has a function of calculating the dry stock number N from the required drying time Ta and the printing interval Ts.

  The control unit 20 includes a timer / counter 201 and a shutter control unit 202 (corresponding to the shutter control unit 84 in FIG. 1). The timer / counter 201 measures the stock time in the storage unit 31 of the drying device 30, the number of printed sheets, the number of sheets P conveyed and stocked in the storage unit 31, and the like. The shutter control unit 202 controls the drive unit 83 based on the detection result of the sheet P by the conveyance detection sensor 331 to perform the opening / closing operation of the shutter 82 of the restriction air blowing unit 36.

  Specifically, after the conveyance detection sensor 331 detects the conveyance of the sheet P into the drying device 30, the shutter control unit 202 sets the shutter 82 to “ The drive unit 83 is controlled to be in the “open” state. Thereafter, when a predetermined opening time has elapsed, the shutter control unit 202 controls the driving unit 83 so that the shutter 82 is in the “closed” state. That is, the shutter control unit 202 sets the shutter 82 in the “open” state in synchronization with the timing when the sheet P is carried into the drying device 30, and blows an air flow toward the upper surface of the sheet bundle PA by the restriction air blowing unit 36. Let it run.

  In addition, the control unit 20 has a function of determining whether or not the total number of printed sheets J is N or more, a function of sequentially discharging the sheets P from the storage unit 31 at a predetermined timing and interval by the sheet discharge unit 50, and the storage unit 31. Has a function of determining whether or not the number of sheets P carried into the printer has reached the total number of printed sheets J.

  For example, the RIP 22 transmits and receives data to and from a host device such as a personal computer (not shown). The control unit 20 converts the image signal received via the RIP 22 into image data by performing scaling processing or gradation processing by the FPGA 23 as necessary.

  The FPGA 23 is a circuit that includes an image processing unit 24 and a data processing unit 25, and based on a control signal from the control unit 20, the image data transmitted from the control unit 20 is subjected to scaling or gradation processing to generate ink. The data is transmitted to the tank 26, the encoder 28, and the recording heads 8K to 8Y. Further, it controls the ejection of ink from the recording heads 8K to 8Y. With this control and the sheet conveyance control by the conveyance belt 11 driven by the conveyance motor 74, the recording process on the sheet is performed.

  The ink tank 26 is a tank that stores ink ejected to the sheet P, and is equipped with a ROM 27 that stores information such as installation time and color. The ink color information stored in the ROM 27 is transmitted to the control unit 20 via the FPGA 23 and is used to determine the specifications such as ink color.

  The encoder 28 is connected to the printing drive roller 12 (see FIG. 1), and outputs a pulse train in accordance with the rotational displacement amount of the rotation shaft of the printing drive roller 12. The control unit 20 calculates the rotation amount by counting the number of pulses transmitted from the encoder 28 via the FPGA 23, and grasps the sheet feed amount (sheet position). Based on the signal from the encoder 28, the controller 20 outputs a correction signal to the motor control IC 73 so that the sheet feed amount by driving the printing drive roller 12 becomes uniform.

  The motor control IC 73 drives the carry motor 74 by an output signal from the control unit 20. The conveyance motor 74 is driven to rotate the printing drive roller 12 and rotate the printing conveyance belt 11 counterclockwise in FIG. 1 to convey the sheet P to the drying device 30.

  Next, the air flow blowing operation control by the shutter control unit 202 will be described. FIG. 12 is a time chart showing the opening / closing operation of the shutter 82 for controlling the blowing of airflow from the upper surface side of the sheet bundle, and FIGS. 13A to 13D are related to the time chart of FIG. FIG. 6 is a schematic diagram showing a hot air blowing operation from the upper surface side of the sheet bundle PA.

  When the leading end of the sheet Pn in the transport direction reaches the arrangement position of the transport detection sensor 331 (see FIG. 7) at time t01, the transport detection sensor 331 is in a “sheet present” state, that is, the sheet Pn is carried into the drying device 30. Detect that. When the conveyance of the sheet Pn advances and the trailing end of the sheet Pn in the conveyance direction passes the arrangement position of the conveyance detection sensor 331 at time t02 (FIG. 7 shows this timing), the conveyance detection sensor 331 indicates “no sheet”. Detect state.

  FIG. 13A shows the state of the drying device 30 at time t1 between the above time t01 and time t02. At this time t1, the rear end of the sheet Pn in the conveyance direction has not yet left the arrangement position of the conveyance detection sensor 331. At this time, warm air is blown from the separation blower 35 to the side surface of the sheet bundle PA. Although not shown here, warm air is also blown from the first to fifth drying air blowing units 371 to 375 on the side surface of the sheet bundle PA. Note that the blowing of warm air onto the side surface of the sheet bundle PA is continued until the printing process is performed and the last sheet P is discharged from the storage unit 31.

  On the other hand, for the regulated air blower 36, the shutter controller 202 controls the drive unit 83 so that the shutter 82 closes the air supply port 811 (see FIG. 8) of the blower fan 81. No hot air blowing is performed. That is, the shutter control unit 202 is in a state in which the shutter 82 closes the air supply port 811 of the blower fan 81 from time t01 when the conveyance detection sensor 331 detects “sheet presence” until time t3 when the predetermined delay time ta elapses. To maintain. Therefore, also at time t2 between time t02 and time t3, as shown in FIG. 13B, the shutter 82 is positioned at the closed position, and hot air is not blown out from the regulated air blower 36. At this time, the sheet Pn is slightly lifted by the air flow from the separating air blowing unit 35 and is in a state of being slightly lifted.

  At time t3, the shutter control unit 202 moves the shutter 82 to the open position and opens the air supply port 811 of the blower fan 81. As a result, as shown in FIG. 13C, the hot air blowing from the regulated air blowing unit 36 to the upper surface of the sheet bundle PA is started. By blowing the hot air from above, the floating of the sheet Pn is restricted, and it is possible to prevent the sheet Pn from being disturbed when the sheet Pn is carried onto the sheet bundle PA. The shutter control unit 84 maintains the shutter 82 in the open position from time t3 to time t4 when a predetermined open time tb elapses. This open time tb is appropriately set in consideration of the time required for the rear end in the conveyance direction of the sheet Pn to completely pass through the downstream end of the carry-in guide portion 33.

  At time t4, the shutter control unit 202 moves the shutter 82 to the closed position and closes the air supply port 811 of the blower fan 81. As a result, as shown in FIG. 13D, the blowing of warm air from the restricted air blowing section 36 to the upper surface of the sheet bundle PA is stopped. At this time, the sheet Pn is in a state where the carry-in to the uppermost surface of the sheet bundle PA is completed. With the completion of loading of the sheet Pn, the lowermost sheet Pb of the sheet bundle PA is discharged from the drying device 30 by the sheet discharge unit 50. On the other hand, the next sheet Pn + 1 is carried into the drying device 30. In response to the carry-in of the sheet Pn + 1, the shutter control unit 202 executes the same control as that of the sheet Pn.

  As described above, according to the printer 1 according to the present embodiment, the plurality of sheets P are stocked in the storage unit 31 in the drying apparatus 30 until the ink is dried while avoiding ink adhesion to each other, and the ink is dried. The sheets P can be discharged sequentially. In addition, instead of replacing the discharged sheet P, the continuously printed sheet P can be carried into the accommodating portion 31. Thereby, the increase in the size of the apparatus, the increase in the number of members and the cost can be suppressed, and the ink discharged onto the sheet P can be sufficiently dried in response to the increase in the speed of the printer 1.

  Moreover, the drying apparatus 30 is not only the separation air blowing unit 35 and the first to fifth drying air blowing units 371 to 375 (first air blowing units) that blow an air flow from the side surface direction of the sheet bundle, but also the upper surface direction of the sheet bundle. The control ventilation part 36 (2nd ventilation part) which blows an airflow from is provided. When the sheet P is carried into the drying device 30, the restriction blower 36 blows an air flow from the upper surface direction of the sheet bundle PA stored in the storage unit 31. As a result, the sheet P that is likely to be swollen or blown away from the side by the air flow can be regulated by the air flow from the upper surface, so that the sheet P is moved to a predetermined stock position (the uppermost surface of the sheet bundle PA). It can be guided stably. Therefore, it is possible to provide the ink jet printer 1 that can quickly dry and discharge the sheet P without causing the conveyance of the sheet P to be disturbed.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the spirit of the present invention. For example, the number of nozzles and the nozzle interval of the recording heads 8K to 8Y can be appropriately set according to the specifications of the apparatus. In this embodiment, the printer 1 is illustrated as an example of the image forming apparatus. However, the present invention can also be applied to other image forming apparatuses such as a copying machine, a facsimile, or a complex machine thereof.

  Moreover, in the said embodiment, although the example which shares the one ventilation fan 41 with the ventilation part 35 for isolation | separation and the ventilation parts 371-375 for 1st-5th was shown, a ventilation fan is separately provided to each ventilation part. It may be provided. In this case, you may make it arrange | position the shutter 82 as shown in FIG. 8 in the air supply port of each ventilation fan. Conversely, the blower fan 81 for the regulated blower 36 may be omitted, and the air flow generated by the blower fan 41 may be guided to the regulated blower 36.

  Furthermore, in the present embodiment, the printer 1 that prints only the front surface of the sheet P is illustrated, but a printer that can print the back surface (double-sided printing) following the front surface may be used. In this case, a duplex printing conveyance path that branches off from the conveyance path 61 and communicates with the registration rollers 6 is provided on the downstream side of the sheet discharge unit 50. A transport path switching plate is provided on the downstream side of the duplex printing transport path. The conveyance path 61 and the conveyance path for double-sided printing are switched by the conveyance path switching plate between the case of single-side printing and the case of double-sided printing, corresponding to each printing.

1 Printer (inkjet recording device)
7 recording section 8 recording head 10 transport unit (part of transport means)
DESCRIPTION OF SYMBOLS 11 Conveyance belt 20 Control part 30 Drying device 31 Storage part 33 Carry-in guide part (a part of conveyance means)
331 Conveyance detection sensor (sensor)
35 Separation blower (part of the first blower)
36 Control air blower (second air blower)
371-375 1st-5th ventilation part for drying (a part of 1st ventilation part)
50 Sheet discharge unit 82 Shutter 84 (202) Shutter control unit (control means)
P sheet PA sheet bundle

Claims (5)

A recording unit for ejecting ink on the sheet;
A drying device that performs a drying process on these sheets while sequentially stacking the sheets after the ink is ejected and stocking them in a sheet bundle shape,
Conveying means for carrying the sheet into the drying device via the recording unit,
The drying device
An accommodating portion for stocking the sheet to be carried in a sheet bundle;
A first air blowing unit for blowing an air flow from a side surface direction of the stocked sheet bundle;
At least when the sheet is carried into the drying device, a second air blowing unit that blows an air flow from the upper surface direction of the sheet bundle;
Only including,
The conveying means includes a guide for guiding the sheet to the accommodating portion on an upper surface,
The first air blower is disposed above the guide and blows air in the side direction of the sheet bundle stocked in the housing from the upstream side in the carry-in direction along the carry-in direction of the sheet into the housing. An ink jet recording apparatus comprising an air blowing means .   The inkjet recording apparatus according to claim 1, wherein the air flow blown by the first blower and the second blower is warm air. A sensor that detects that the sheet that has passed through the recording unit has been carried into the drying device;
Control means for controlling the operation of blowing the air flow by the second air blowing section,
The control means starts the air flow spraying operation by the second air blowing unit after the sensor detects the loading of the sheet, continues the spraying for a predetermined time, and then stops the spraying operation. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is an ink jet recording apparatus. The first air blower blows the air flow toward the side surface of the sheet bundle from the upstream side in the loading direction on the lower side of the guide in order to pass the air flow between the sheets of the sheet bundle. The inkjet recording apparatus according to claim 1, comprising: It said conveying means comprises a conveyor belt endless conveying the sheet toward the downstream side from the upstream side of the recording portion, and the guide for guiding the sheet to the receiving portion from the downstream end of the conveying belt,
The sheet carry-in position by the guide is set at a position that is higher than the bottom surface of the storage portion by a predetermined height,
The inkjet recording apparatus according to claim 4, wherein the second air blowing unit blows an air flow in the vicinity of an entrance of the storage unit into which a sheet is carried by the guide.

Images