JP2009028917A - Recording apparatus and liquid ejecting apparatus - Google Patents

Abstract

The present invention prevents the quality of a recorded image from being deteriorated by an air flow generated by a suction platen.
A transport unit 210 that transports a recording sheet 150 in a transport direction, a recording head 232 that ejects ink toward the recording sheet 150 transported by the transport unit 210, and a transport unit that forms negative pressure on the surface. The ink jet recording apparatus 100 includes a suction platen 250 having a function of sucking the recording paper 150 fed from 210 and positioning the recording paper 150 at a position facing the recording head 232. Includes a plurality of suction areas 280 and 290 that are arranged in the transport direction and individually generate a suction force with respect to the recording paper 150. Among the plurality of suction areas 280 and 290, the suction areas 280 and 290 where the recording paper 150 exists. In FIG. 2, the recording paper 150 is sucked and the recording paper 150 is placed in the suction areas 280 and 290 where the recording paper 150 does not exist. It limits the suction.
[Selection] Figure 7

Description

  The present invention relates to a recording apparatus and a liquid ejecting apparatus. More specifically, the present invention relates to a recording apparatus and a liquid ejecting apparatus including a suction platen that positions by recording a recording medium.

  There is an ink jet recording apparatus in which a liquid such as ink is ejected from a recording head provided with fine nozzles to adhere to a recording medium. This type of apparatus includes a recording head that reciprocates in a predetermined main scanning direction, and a conveyance unit that moves a recording medium in a conveyance direction that intersects the main scanning direction. By combining main scanning and conveyance, An image is formed by adhering liquid to an arbitrary area on the recording medium.

  In the ink jet recording apparatus as described above, the reciprocating range in the main scanning direction is determined by the specifications of the apparatus, and there are some that can record a large image such as a poster having a main scanning width exceeding 1 m. On the other hand, the length of the recording medium is not limited in the transport direction. Therefore, there is a recording apparatus that loads a roll on which a long recording medium is wound to form a long image on a banner, a hanging curtain, or the like.

  On the other hand, in an ink jet recording apparatus, a platen gap that is a distance between a nozzle and a recording medium strongly affects the quality of a recorded image. Accordingly, a platen for positioning the recording medium by supporting the recording medium from the back surface at a position facing the recording head is provided in the ink jet recording apparatus.

  Further, the flatness of the recording medium when ink is attached also changes the platen gap. Therefore, particularly in a recording apparatus that uses roll paper as the recording medium, there are cases in which the wrinkle remains on the recording medium pulled out from the roll, and as measures against the high bending rigidity of the recording medium itself, Some models have a suction platen. Many suction platens have a plurality of suction holes communicating with the surface thereof, and the recording medium is adsorbed on a flat surface by communicating the suction holes with some kind of reduced pressure source.

  Patent Document 1 below describes a plotter including a platen that sucks a worksheet as a recording medium with a suction fan. In this plotter, the number of rotations of the suction fan changes according to the width of the worksheet, and the worksheet is reliably sucked.

  Patent Document 2 below describes a paper guide mechanism including a highly airtight fan box that houses a fan, and a guide plate that has air intake holes arranged on one surface of the fan box. With such a structure, the drawing medium can be efficiently adsorbed using a small capacity fan.

  Furthermore, Patent Document 3 below describes a platen including a suction fan that can select an operation according to the physical properties of the drawing medium. Thereby, it can convey, without roughening surface properties, such as a back print film.

  Furthermore, Patent Document 4 below describes forming a recess on the surface of a platen having a suction fan. Thereby, wrinkles of the recording material are less likely to occur.

As described above, in the recording apparatus provided with the suction platen, the recording medium is reliably positioned and an appropriate platen gap is maintained. Even when a curl or the like is attached, the recording medium becomes flat on the suction platen, and a uniform platen gap is maintained. Therefore, the high recording quality of the ink jet recording apparatus can be effectively utilized.
Japanese Patent Laid-Open No. 06-015902 JP 2001-089979 A JP 2002-127515 A JP 2006-231705 A

  In an ink jet recording apparatus, ink ejected from a recording head flies between the recording head and a recording medium due to inertia of kinetic energy given when ejected. On the other hand, in a period in which the front end side of the recording medium starts to approach the suction platen in the transport direction and a period in which the rear end side of the recording medium comes out of the suction platen in the transport direction, a part of the suction holes of the suction platen The recording head is exposed to the recording medium without being blocked by the recording medium. Even when the recording medium is narrower than the platen, part of the suction holes are exposed to the recording head.

  If the suction platen performs a suction operation in this state, the flying ink may be sucked into the suction holes. The ink whose orbit has been changed due to the suction is attached to a region different from the originally intended region on the surface of the recording medium. For this reason, in a recording apparatus having a suction platen, the quality of a recorded image may deteriorate in the vicinity of the edge of the recording medium.

  In order to solve the above problems, as a first embodiment of the present invention, a transport unit that transports a recording medium in the transport direction, and a recording head that ejects ink toward the recording medium transported by the transport unit, A recording apparatus having a function of sucking a recording medium fed from a conveyance unit by forming a negative pressure on the surface, and a suction platen for positioning the recording medium at a position facing the recording head. The suction platen has a plurality of regions that individually generate suction force to the recording medium in the transport direction, and sucks the recording medium in the region where the recording medium exists as the recording medium is transported. In addition, a recording apparatus is provided that restricts suction in an area where no recording medium exists. As a result, when a part of the suction hole of the suction platen is exposed to the recording head, the suction by the suction platen is restricted, and the trajectory of the ink ejected from the recording head and flying is generated by the suction. Is prevented from changing. Therefore, a high-quality image can be recorded even at the edge of the recording medium.

  In the recording apparatus, each of the plurality of regions may have a suction fan that individually operates or stops to generate or stop a suction force. Thereby, the suction in each region can be started or stopped by electrical control.

  Further, in the recording apparatus, the suction platen may include a negative pressure source common to the plurality of regions, and an opening / closing valve that individually connects or blocks each of the plurality of regions to the negative pressure source. . Thus, while the decompression source such as a suction fan is operated in a steady manner, the start or stop of suction in each region can be quickly switched by opening and closing the valve.

  Furthermore, in the recording apparatus, a detection unit that detects a region where the recording medium exists on the surface of the suction platen based on an amount of the recording medium that has been transported after the transportation unit has started to transport the recording medium. You may prepare. Thereby, the start or stop of suction can be controlled without providing a detection mechanism such as an additional sensor.

  Furthermore, the recording apparatus may further include a detection unit including a switch that is interrupted by a recording medium present on the surface of the suction platen. Accordingly, it is possible to reliably detect the presence of the recording medium on the surface of the suction platen and increase the accuracy of control by the control unit.

  Furthermore, in the recording apparatus, the plurality of areas are arranged in a direction intersecting the transport direction, and the recording medium is sucked in an area where the recording medium exists among the plurality of areas. Suction may be limited in an area where no recording medium exists. As a result, the above effect can be enjoyed even when an image is recorded on a recording medium having a narrow width orthogonal to the transport direction.

  As a second aspect of the present invention, a transport unit that transports the recording medium in the transport direction, a recording head that ejects ink toward the recording medium transported by the transport unit, and a negative pressure on the surface are formed. And a suction platen for sucking and positioning the recording medium fed from the transport unit at a position facing the recording head, the suction platen being arranged in the transport direction, When the front end of the recording medium passes over the surface of the suction platen with respect to the transport direction and includes a plurality of areas for individually sucking the medium, the area where the recording medium exists is upstream of the transport direction in the plurality of areas. When the recording medium is sequentially sucked from the side, and the trailing end of the recording medium passes over the surface of the suction platen in the transport direction, the area where the recording medium exists is out of the plurality of areas. Recording device for limiting the suction for sequentially the recording medium from the upstream side is provided for. Thereby, the area | region to which it attracts | sucks and the area | region which restrict | sucked the suction are finely arranged, and a high suction force can be maintained.

  Further, as a third aspect of the present invention, a transport unit that transports the ejected medium in the transport direction, a liquid ejecting head that ejects liquid toward the ejected medium transported by the transport unit, and a negative pressure on the surface A liquid ejecting apparatus that includes a suction unit that sucks and positions a recording medium that is formed and fed from the transport unit at a position facing the liquid ejecting head. When the front end of the ejection medium passes over the surface of the suction unit in the transport direction, the area where the ejection medium exists is the transport direction in the plurality of areas. When the target medium is sequentially sucked from the upstream side and the rear end of the target medium passes over the surface of the suction platen with respect to the transport direction, the region where the target medium is present in the plurality of regions is the transport direction. About upstream The liquid ejecting apparatus is provided which limits the suction against et successively the ejection target medium. Thereby, the above-described effect can be enjoyed also in the liquid ejecting apparatus.

  Furthermore, as a fourth aspect of the present invention, a transport unit that transports the recording medium in the transport direction, a liquid ejecting head that ejects liquid toward the recording medium transported by the transport unit, and a negative pressure on the surface And a suction platen that sucks and positions the recording medium fed from the transport unit at a position facing the liquid ejecting head, the suction platen being arranged in the transport direction, When the front end of the recording medium passes over the surface of the suction platen in the conveyance direction, the area where the recording medium exists is included in the conveyance direction. When the recording medium is sequentially sucked from the upstream side and the rear end of the recording medium passes over the surface of the suction platen in the transport direction, the area where the recording medium exists is a plurality of areas, The liquid ejecting apparatus is provided for limiting the suction for sequentially the recording medium from an upstream side for feeding direction. Thereby, the above-described effect can be enjoyed also in the liquid ejecting apparatus.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. Further, a sub-combination of these feature groups can be an invention.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a perspective view showing an appearance of an ink jet recording apparatus 100 according to one embodiment. The ink jet recording apparatus 100 can perform recording on large sheets such as JIS standard A0 size and B0 size, or roll paper having a paper width comparable to these.

  As shown in the figure, the ink jet recording apparatus 100 includes a casing 110 including an upper casing 112 and a lower casing 114 that are stacked on each other, and a small casing 116 that is suspended below the lower casing 114. Furthermore, it has the leg part 120 which supports the housing | casing 110 from the downward direction. Thereby, a space for discharging the recording paper 150 can be formed below the housing 110.

  The upper housing 112 accommodates a recording head 232 and the like which will be described later. On the other hand, the lower housing 114 accommodates a suction platen 250, which will be described later. Further, the small casing 116 accommodates the waste liquid absorber 260. The waste liquid absorber 260 accumulates ink that has not been adhered to the recording paper 150 while being discharged from the recording head 232.

  The upper casing 112 is provided with an operation panel 130 that is used when the ink jet recording apparatus 100 is operated in a stand-alone manner. The operation panel 130 may be provided with a display panel, a lamp, and the like that indicate the operation state of the ink jet recording apparatus 100. On the other hand, the lower housing 114 is provided with a cartridge holder 140 into which an ink cartridge 240 containing ink to be supplied to the recording head 232 is loaded.

  In the ink jet recording apparatus 100 as described above, the recording sheet 150 on which an image is recorded is sent forward from between the upper casing 112 and the lower casing 114. The fed recording sheet 150 hangs downward due to its own weight. Therefore, a guide surface 252 that smoothly guides the recording paper 150 is formed at the front end of the suction platen 250 that can be seen in the gap between the upper housing 112 and the lower housing 114.

  FIG. 2 is a perspective view showing the ink jet recording apparatus 100 as seen from the back. As shown in the figure, on the rear surface of the ink jet recording apparatus 100, a spindle 160 that is horizontally stretched and a roll 152 that is horizontally supported by being inserted through the spindle 160 are disposed at the rear of the lower housing 114. Installed. The recording paper 150 shown in FIG. 1 is drawn from the roll 152, passed through the inside of the housing 110, and drawn to the front.

  FIG. 3 is a perspective view showing the internal mechanism 200 of the ink jet recording apparatus 100. The internal mechanism 200 appears when the casing 110 is removed from the ink jet recording apparatus 100.

  As shown in the figure, the ink jet recording apparatus 100 includes a guide rail 220 extending in the horizontal direction over the entire width and a carriage 230 that reciprocates horizontally along the guide rail 220 in the upper housing 112. Prepare. As will be described later, a recording head 232 that ejects ink is mounted on the carriage 230. Further, below the guide rail 220, a transport unit 210 that moves the recording paper 150 from the rear to the front is disposed.

  On the other hand, a suction platen 250 having a horizontal surface is disposed below the guide rail 220 inside the lower housing 114. The lower housing 114 also houses the ink cartridge 240. Furthermore, the waste liquid absorber 260 accommodated in the small casing 116 is exposed to the right side of the leg portion 120 in the drawing.

  FIG. 4 is an enlarged perspective view of a part of the internal mechanism 200 shown in FIG. As shown in the figure, a conveyance unit 210 including a conveyance driving roller 212 and a conveyance driven roller 214 is formed behind the suction platen 250.

  The transport driving roller 212 is rotationally driven by a transport motor (not shown). On the other hand, the transport driven roller 214 is urged downward through the roller holder 216 and is rotated in contact with the transport drive roller 212.

  When the recording paper 150 is sandwiched between the transport driving roller 212 and the transport driven roller 214 as described above, the recording paper 150 is pressed against the transport driving roller 212 by the transport driven roller 214. As a result, the sheet is sent to the upper surface of the suction platen 250 according to the rotation of the transport driving roller 212.

  FIG. 5 is a cross-sectional view schematically showing the structure and function of the suction platen 250. As shown in the figure, the suction platen 250 has a number of suction holes 259 on its upper surface. The lower ends of the suction holes 259 communicate with the decompression chambers 283 and 293 formed inside the suction platen 250, respectively. Here, the suction platen 250 has two decompression chambers 283 and 293 that are independent of each other.

  The decompression chambers 283 and 293 communicate with suction fans 284 and 294 through ducts 285 and 295, respectively. When the suction fans 284 and 294 are operated, the decompression chambers 283 and 293 are negatively discharged by discharging the air therein. As a result, the suction holes 259 communicating with the decompression chambers 283 and 293 generate a suction force, and the recording paper 150 is attracted to the upper surface of the suction platen 250.

  Further, as already described, the suction platen 250 has two independent decompression chambers 283 and 293, and is provided with suction fans 284 and 294, respectively. Therefore, when the suction fan 284 is operated, the suction hole 259 communicating with the decompression chamber 283 exhibits the suction force, and when the suction fan 294 is operated, the suction hole 259 communicated with the decompression chamber 293 exhibits the suction force.

  Each of the suction fans 284, 294 is coupled to a power source 256 via switches 253, 255 and is individually stopped or activated. Therefore, a suction force can be generated in a specific region on the surface of the suction platen 250 by electrical control via the switches 253 and 255, and can be stopped. The switches 253 and 255 are controlled to be opened and closed by the control unit 258. The control unit 258 opens and closes the switches 253 and 255 based on information obtained from the plurality of sensors 236, 237, and 238 disposed above the suction platen 250.

  Here, one sensor 236 detects whether or not the recording sheet 150 exists on the suction platen 250 immediately before the suction hole 259 on the most upstream side in the conveyance direction M of the recording sheet 150. The other sensor 237 detects whether or not the recording sheet 150 exists on the suction platen 250 at the boundary between the two decompression chambers 283 and 293. Further, another sensor 238 detects whether or not the recording sheet 150 exists on the suction platen 250 immediately after the most downstream suction hole 259 in the conveyance direction M of the recording sheet 150.

  The control unit 258 notified of the presence or absence of the recording paper 150 from each of the sensors 236, 237, and 238, as described later with reference to FIGS. 7 and 8, switches 253, The opening and closing of 255 is controlled. The sensors 236, 237, and 238 as described above can be formed by, for example, mounting an optical sensor that detects a change in reflectance on the surface of the suction platen 250 on the carriage 230.

  FIG. 6 is a plan view showing the layout of the suction areas 280 and 290 on the suction platen 250 in the conveyance path 300 of the recording paper 150. As shown in the figure, the recording paper 150 drawn from the roll 152 loaded behind the ink jet recording apparatus 100 is transported in the transport direction M by the transport unit 210 and sent onto the front suction platen 250. .

  The suction platen 250 has a number of suction holes 259 opened on the surface thereof, and when the decompression chambers 283 and 293 immediately below are decompressed, a negative pressure is generated on the surface of the suction platen 250 to attract the recording paper 150. To do. As a result, even when the recording paper 150 is curled or the like, it is attracted to the flat surface of the suction platen 250 and becomes flat. Therefore, on the suction platen 250, the interval between the recording paper 150 and the recording head 232 is accurately maintained, and the quality of the recorded image is kept high.

  As described above, the suction platen 250 includes the two decompression chambers 283 and 293 that generate or stop the suction force independently of each other. Therefore, two suction areas 280 and 290 that are divided into two in the transport direction M of the recording paper 150 are formed on the surface of the suction platen 250.

  On the other hand, the carriage 230 reciprocates along the guide rail 220 above the suction platen 250. A recording head 232 having a large number of nozzles 234 is mounted on the carriage 230. Therefore, by combining the driving of the conveyance of the recording paper 150 and the reciprocating movement of the recording head 232, ink can be ejected and adhered to an arbitrary area of the recording paper 150. In addition, since the recording head 232 includes a large number of nozzles 234, a large number of pixels can be formed by a single scan by the carriage 230, so that the recording speed can be improved.

  Further, the carriage 230 includes sensors 236, 237, and 238 along with the recording head 232. The operation of the suction platen 250 using the sensors 236, 237, and 238 will be described later.

  FIG. 7 is a diagram schematically showing the transition of the operation state of the suction platen 250 accompanying the conveyance of the recording paper 150. As shown in the drawing, on the upper surface of the suction platen 250, the recording paper 150 is transported by the transport unit 210 and proceeds along the transport direction M while sequentially covering the upper surface of the suction platen 250. Each of the sensors 236, 237, and 238 notifies the control unit 258 that it has been detected when the recording paper 150 is present immediately below it.

  On the other hand, when the recording sheet 150 reaches the suction platen 250, the control unit 258 stops the suction fans 284 and 294 with both the switches 253 and 255 opened. Accordingly, the suction platen 250 does not attract the recording paper 150. However, as shown in the drawing, the conveyance unit 210 is arranged so that the conveyance driven roller 214 is deformed downstream with respect to the vertical line passing through the central axis of the conveyance drive roller 212, so that the recording paper 150 Therefore, the leading edge of the recording paper 150 moves along the upper surface of the suction platen 250 due to the rigidity of the recording paper 150 itself.

  Next, as shown by the solid line in the drawing, the front end of the advanced recording paper 150 reaches a position directly below the central sensor 237, that is, the suction area 280 is entirely covered with the recording paper 150. When receiving the notification from the sensor 237, the control unit 258 turns on the switch 253 to operate the suction fan 284. As a result, as shown by an arrow S in the drawing, suction in the suction region 280 of the suction platen 250 is started via the duct 285. At this time, suction in the suction region 290 has not yet started.

  Subsequently, as indicated by a dotted line in the drawing, the recording paper 150 is further conveyed and reaches the left end of the suction platen 250 in the drawing and is detected by the sensor 238. The control unit 258 notified of the detection of the recording paper 150 from the sensor 238 turns on the switch 255 and operates the suction fan 294. As a result, the suction in the suction region 290 is started as indicated by the dotted arrow in the drawing.

  Through the series of controls described above, the suction platen 250 sucks the suction holes 259 covered with the recording paper 150, but does not suck the suction holes 259 exposed to the recording head 232. Therefore, the exposed suction hole 259 does not suck the surrounding air and generate an air current, and the trajectory of the ink ejected from the recording head 232 is not disturbed.

  FIG. 8 is a diagram showing the structure and operation of a suction platen 250 according to another embodiment in contrast to FIG. As shown in the figure, the suction platen 250 includes three decompression chambers 283, 287, and 293 that are independent of each other. The decompression chambers 283, 287, 293 communicate with the suction hole 259 immediately above the decompression chambers 283, 287, 293, respectively.

  The decompression chambers 283, 287, and 293 also communicate with suction fans (not shown) that are individually connected via individual ducts 285, 289, and 295. Accordingly, the three suction regions 280, 281, and 290 formed above the decompression chambers 283, 287, and 293 can individually start or stop suction.

  Further, the carriage 230 is mounted with four sensors 236, 237, 238 and 239 in response to the suction areas 280, 281 and 290. Sensors 236, 237, 238, and 239 are the positions of the most upstream suction holes 259 in the conveyance direction M of the recording paper 150, the positions of the boundaries between the decompression chambers 283, 287, and 293, and the most downstream suction holes. 259. Each of the sensors 236, 237, 238, and 239 detects the presence or absence of the recording paper 150 at each position, and notifies the control unit 258 of the detection result.

  The suction platen 250 having the above-described structure initially stops the suction as in the case of the suction platen 250 shown in FIG. Eventually, when the recording sheet 150 conveyed by the conveyance unit 210 reaches the end of the suction area 280, that is, the boundary between the suction areas 280 and 281, the second sensor 237 detects the conveyance direction M. The control unit 258 notified of the detection of the recording sheet 150 from the sensor 237 starts the suction of the suction region 280 via the duct 285 as indicated by an arrow S in the drawing.

  FIG. 9 is a view for explaining the subsequent operation of the suction platen 250 shown in FIG. As indicated by a solid line in the drawing, the leading edge of the recording paper 150 conveyed by the conveying unit 210 advances to the position of the boundary between the suction areas 281 and 290 and is detected by the sensor 238. When the sensor 238 notifies the control unit 258 that the recording paper 150 has been detected, the control unit 258 starts suction in the suction region 281 through the duct 289 as indicated by an arrow S in the drawing.

  Further, as indicated by a dotted line in the figure, when the leading end of the recording paper 150 conveyed by the conveying unit 210 reaches the end of the suction platen 250, it is detected by the sensor 239. When the control unit 258 is notified from the sensor 239 that the recording paper 150 has been detected, the control unit 258 starts the suction by the suction region 290 as indicated by a dotted arrow in the drawing.

  Thus, the suction of the recording paper 150 is started on the entire surface of the suction platen 250. As described above, in the suction platen 250, the suction operation is not started in the suction regions 280, 281, and 290 where the suction holes 259 are exposed to the recording head 232. Therefore, the airflow flowing into the opened suction hole 259 does not disturb the trajectory of the ink droplets ejected from the recording head 232.

  Further, the surface of the suction platen 250 is divided into three suction areas 280, 281, and 290, and each of the suction platens 250 starts or stops sucking individually, so that the suction area 280 follows the movement of the leading edge of the recording paper 150. , 281 and 290 can be finely controlled. Therefore, suction by the exposed suction hole 259 is stopped, while a high suction force can be exerted on the recording paper 150.

  FIG. 10 is a view showing the structure and operation of a suction platen 250 according to another embodiment. As shown in the figure, the suction platen 250 includes a suction platen 250 having the same structure as that of the embodiment shown in FIG.

  On the other hand, in the ink jet recording apparatus 100, two recording heads 231 and 233 arranged along the conveyance direction M of the recording paper 150 are mounted on the carriage 230. With such a structure, the number of pixels that can be formed by one scan of the carriage 230 can be increased, and the effective operation speed of the ink jet recording apparatus 100 can be improved. Further, the boundary between the suction areas 280 and 290 is formed at a position facing the boundary between the recording heads 231 and 233.

  Since the recording heads 231 and 233 have a precise structure, the production yield decreases when the number of nozzles of the single recording heads 231 and 233 is increased. Therefore, the number of nozzles can be increased at a low manufacturing cost by combining a plurality of recording heads 231 and 233 created with the number of nozzles within a range in which a high yield can be maintained.

  Further, the two recording heads 231 and 233 can be operated individually. Therefore, as indicated by the solid line in the figure, when the leading edge of the recording paper 150 is conveyed to the boundary between the recording heads 231 and 233, ink is ejected from one recording head 231 and is brought close to the leading edge of the recording paper 150. Start image recording. At this time, the other recording head 233 is at rest.

  In accordance with the operation state of the recording heads 231 and 233 as described above, the control unit 258 starts suction of the recording paper 150 in the suction area 280 as indicated by an arrow S in the drawing. On the other hand, the suction of the recording paper 150 by the suction area 290 is not started and is kept at rest. Thereby, the trajectory of the ink ejected from the recording head 231 is prevented from being disturbed by the air flow generated by the suction of the suction platen 250.

  Subsequently, when the recording of the image by the recording head 231 near the leading end of the recording paper 150 is completed, the transport unit 210 transports the recording paper 150 and advances it. As a result, when the leading edge of the recording paper 150 advances to below the other recording head 233, the control unit 258 also starts to suck the recording paper 150 by the suction area 290. Thereby, a high-speed recording operation using the two recording heads 231 and 233 is started. The suction platen 250 sucks the recording paper 150 over the entire surface.

  In the above embodiment, the suction fans 284 and 294 are operated or stopped for the purpose of simplifying the description. However, the ink droplets ejected from the recording heads 231, 232, and 233 are not disturbed. If so, the suction platen 250 may be operating. Therefore, when either of the sensors 236 and 238 does not detect the recording sheet 150, the rotation speed of the suction fans 284 and 294 can be reduced. As a result, the suction fans 284 and 294 can continue to maintain a weak suction force, and the startup time for sucking the recording paper 150 again can be shortened.

  In the above embodiment, the control unit 258 controls the suction platen 250 based on the detection of the recording paper 150 by the sensors 236, 237, and 238, and the operation states of the plurality of recording heads 231 and 233. The case of controlling the suction platen 250 has been described. However, the control method by the control unit 258 is not limited to these.

  For example, in the ink jet recording apparatus 100, the conveyance amount of the recording paper 150 by the conveyance unit 210 is precisely controlled. Therefore, once the control unit 258 detects, for example, the leading end position of the conveyed recording paper 150, the control unit 258 can detect and control the leading end position of the recording paper 150 from the transport amount by the transport unit 210.

  FIG. 11 is a perspective view showing an appearance of an ink jet recording apparatus 400 according to another embodiment. As shown in the drawing, an ink jet recording apparatus 400 includes a recording unit casing 414, a rear casing 412 protruding rearward thereof, and a paper cartridge 416 mounted on the recording unit casing 414 from the entire surface. 410.

  The rear casing 412 can be loaded with roll paper (not shown). The roll paper drawn from the loaded roll paper passes through the inside of the recording unit housing 414 and is discharged to a discharge tray 470 formed on the upper surface of the paper cartridge 416. The ink jet recording apparatus 400 can also record an image on a single sheet of recording paper 154 loaded in the paper cartridge 416. Also in this case, the recording sheet 154 on which the image is recorded is folded back in the recording unit housing 414 and discharged to the discharge tray 470.

  FIG. 12 is a perspective view showing the internal mechanism 500 of the ink jet recording apparatus 400. As shown in the figure, inside the recording unit casing 414, a conveying unit 510, a suction platen 550, and a discharge driven roller 518 that are parallel to each other are sequentially arranged. The suction platen 550 disposed in front of the transport unit 510 has a horizontal surface having a number of suction holes 559.

  The conveyance unit 510 includes a conveyance driving roller 512 and a conveyance driven roller 514, as in the case of the ink jet recording apparatus 100. The transport driving roller 512 is rotationally driven by a transport motor (not shown). On the other hand, the transport driven roller 514 is urged downward through a roller holder 516 that rolls about the shaft 517, and is rotated in contact with the transport drive roller 512. Therefore, when the recording paper 150 is sandwiched between the transport driving roller 512 and the transport driven roller 514, the recording paper 150 is pressed against the transport driving roller 512 by the transport driven roller 514, and the suction platen 550 is rotated according to the rotation of the transport driving roller 512. It is sent out to the top surface.

  Further, the ink jet recording apparatus 400 includes a discharge driven roller 518. Since the discharge driven roller 518 contacts the recording paper 154 having the recorded image, a gear-shaped or spur-shaped roller is used for the purpose of reducing the contact area. As a result, the recording sheet 154 can be moved to the rear end of the single sheet recording sheet 154 under a certain control. In other words, the recording head 232 may eject ink even during a period in which the trailing edge of the recording paper 154 passes over the suction platen 550.

  FIG. 13 is a diagram illustrating a conveyance path of the recording paper 154 in the internal mechanism 500 of the ink jet recording apparatus 400. Further, a roll 552 inserted through a spindle 560 is loaded behind the ink jet recording apparatus 400. In this embodiment, the vicinity of the rear end of the single sheet recording paper 154 supplied from the paper cartridge 416 is sucked. A case of passing over the platen 550 will be described.

  As shown in the figure, the suction platen 550 has a number of suction holes 559 on its surface. Since the structure of the suction platen 550 itself is substantially the same as that of the suction platen 250 shown in FIG. 6, the illustration is omitted. However, similar to the suction platen 250, two suction regions 580 and 590 adjacent in the conveyance direction of the recording paper 150 are formed. Have.

  On the other hand, a guide rail 520 extending in the longitudinal direction of the suction platen 550 and a carriage 530 that reciprocates along the guide rail 520 are disposed above the suction platen 550. A recording head 532 that ejects ink is mounted on the carriage 530. The recording head 532 includes a large number of nozzles 534, and a large number of pixels can be formed by a single pass of the carriage 530.

  In addition, the carriage 530 is equipped with sensors 536, 537, and 538 that detect the presence or absence of the recording paper 150. The sensors 536, 537, and 538 are arranged at the boundary between the front and rear ends of the suction platen 550 and the two suction regions 580 and 590 in the suction platen 550 in the conveyance direction M of the recording paper 150.

  In this state, the carriage 530 reciprocates on the suction platen 550 along the guide rail 520. Accordingly, by combining the driving of the conveyance of the recording paper 154 and the reciprocating movement of the recording head 532, ink can be ejected and adhered to an arbitrary region of the recording paper 154.

  Further, since the suction hole 559 forms a negative pressure on the surface of the suction platen 550, the recording paper 154 is attracted to the suction platen 550. Thereby, even when the recording paper 154 is curled or the like, it becomes flat by being adsorbed on the surface of the suction platen 550. Therefore, the interval with respect to the recording head 532 is accurately maintained, and the quality of the recorded image is also kept high.

  FIG. 14 is a cross-sectional view schematically showing a state in which the recording operation for the recording paper 154 is being performed on the suction platen 550. In the state indicated by the dotted line in the drawing, the rear end of the recording paper 154 has not yet reached the suction platen 550. Accordingly, at this time, the recording paper 154 is sucked in both the two suction areas 580 and 590.

  When the recording paper 154 is further transported and advanced as shown by a solid line in the drawing, the control unit 258 is notified by the sensor 536 that the recording paper 154 no longer exists. Therefore, the control unit 258 stops the suction of the recording paper 154 in the suction area 580. This prevents the airflow flowing into the suction hole 259 from disturbing the trajectory of the ink droplets ejected from the recording head 532.

  Subsequently, as indicated by a solid line in the drawing, when the rear end of the recording sheet 154 passes the boundary between the suction areas 580 and 590, the sensor 537 indicates that the recording sheet 154 no longer exists. 258 is notified. Therefore, the control unit 258 stops the suction in the suction region 580. As a result, the suction of the recording paper 154 by the suction platen 550 is stopped, but since the length of the recording paper 154 extending backward from the discharge driven roller 518 is short, the recording paper 154 pressed by the discharge driven roller 518 is sucked. It moves along the upper surface of the platen 550.

  FIG. 15 is a diagram showing the structure and operation of a suction platen 550 according to another embodiment in contrast to FIG. As shown in the figure, the suction platen 550 includes three decompression chambers 583, 587, and 593 that are independent of each other. The decompression chambers 583, 587, and 593 communicate with the suction hole 259 immediately above the decompression chambers 583, 587, and 593, respectively.

  The decompression chambers 583, 587, and 593 also communicate with suction fans (not shown) that are individually connected via individual ducts 585, 589, and 595. Accordingly, the three suction regions 580, 581 and 590 formed above the decompression chambers 583, 587 and 593 can start or stop suction individually.

  Further, in response to the suction areas 580, 581, 590, the carriage 530 is mounted with four sensors 536, 537, 538, 539. Sensors 536, 537, 538, and 539 are the positions of the suction holes 559 on the most upstream side in the conveyance direction M of the recording paper 154, the positions of the boundaries between the decompression chambers 583, 587, and 593, and the suction holes on the most downstream side. 559 is disposed at the position. Each of the sensors 536, 537, 538, and 539 detects the presence or absence of the recording paper 154 and notifies the control unit 258 of the detection result.

  As indicated by a dotted line in the drawing, the trailing edge of the recording paper 154 conveyed by the conveying unit 510 is detected by the sensor 537 when it passes the position of the boundary between the suction areas 580 and 581. When the sensor 237 notifies the control unit 258 to that effect, the control unit 258 stops the suction by the suction region 281.

  Further, as indicated by a solid line in the figure, when the rear end of the recording paper 154 conveyed by the conveying unit 510 passes the boundaries of the suction areas 581 and 590, the fact is detected by the sensor 538. When the control unit 258 is notified from the sensor 538 that the recording paper 154 has passed, the control unit 258 stops the suction in the suction region 290. Thus, the suction of the recording paper 154 is stopped on the entire surface of the suction platen 550.

  As described above, in the suction platen 550, the suction operation is stopped in the suction regions 580, 581, and 590 where the suction holes 559 are exposed to the recording head 532. Therefore, the airflow flowing into the opened suction hole 259 does not disturb the trajectory of the ink droplets ejected from the recording head 532.

  Further, the suction platen 550 is divided into three suction areas 580, 581 and 590, and each of the suction platens 550 starts or stops the suction individually, so that the suction follows the movement of the rear end of the recording paper 154. It is possible to finely control the stoppage of suction in the areas 580, 581 and 590. Accordingly, suction by the exposed suction hole 559 is stopped, while a high suction force can be exerted on the recording paper 154.

  For the sake of brevity, the sensors 536 and 538 are disposed directly above the nozzle 534 in the above embodiment. However, in the ink jet recording apparatus 400, the conveyance amount is precisely controlled by the conveyance unit 510 of the recording paper 154. The dimensions of the recording paper 154 in the transport direction are known in advance. Therefore, once the control unit 258 detects, for example, the leading end position of the transported recording paper 154, the control unit 258 can know the leading end position of the recording paper 154 from the transport amount by the transport unit 510 thereafter.

  Further, the rear end position of the recording paper 154 can be known from the discharge amount by the discharge drive roller 519 and the discharge driven roller 518. Therefore, the number and arrangement of the sensors 536 and 538 to be mounted can be selected in a wide range.

  FIG. 16 is a view showing the structure and operation of a suction platen 550 according to another embodiment. As shown in the figure, the suction platen 550 has the same structure as that of the embodiment shown in FIG.

  On the other hand, in the ink jet recording apparatus 100, two recording heads 531 and 533 arranged along the conveyance direction M of the recording paper 154 are mounted on the carriage 530. With such a structure, the number of pixels that can be formed by one scan of the carriage 530 can be increased, and the effective operation speed of the ink jet recording apparatus 100 can be improved. Further, the boundaries of the suction areas 580 and 590 are formed at positions facing the boundaries of the recording heads 531 and 533.

  Since the recording heads 531 and 533 have a precise structure, the production yield decreases when the number of nozzles of the single recording heads 531 and 533 is increased. Therefore, the number of nozzles can be increased at a low manufacturing cost by combining a plurality of recording heads 531 and 533 created with the number of nozzles within a range in which a high yield can be maintained.

  Further, the two recording heads 531 and 533 can be operated individually. Therefore, as shown by the dotted line in the figure, when the rear end of the recording paper 154 is conveyed to the boundary between the recording heads 531 and 533, ink is ejected from one recording head 533, and the rear end of the recording paper 154 is obtained. Record an image in the vicinity. At this time, the other recording head 531 is at rest.

  The control unit 258 stops the suction of the recording paper 154 in the suction area 580 according to the operation state of the recording heads 531 and 533 as described above. On the other hand, the suction of the recording paper 154 by the suction area 590 continues without stopping. This prevents the trajectory of the ink ejected from the recording head 531 from being disturbed by the airflow generated by the suction of the suction platen 550.

  Subsequently, when the recording of the image by the recording head 533 in the vicinity of the rear end of the recording paper 154 is completed, the discharge unit including the discharge driven roller 518 conveys the recording paper 154 and advances it. As a result, when the leading edge of the recording paper 154 advances below the other recording head 233, the control unit 258 also stops the suction of the recording paper 154 by the suction region 290. Thus, the recording operation using the two recording heads 531 and 533 is completed. The suction platen 550 stops sucking the recording paper 154 over the entire surface.

  In the above-described embodiment, for the purpose of simplifying the description, the suction is described as start or stop. However, the suction platen 550 is stopped as long as it does not disturb the trajectory of the ink droplets ejected from the recording head 532. It does not matter if it works without it. Therefore, when any of the sensors 536, 537, and 538 has not detected the recording paper 154, a structure in which the rotation speed of the suction fan 254 is reduced can be employed. As a result, the suction fan 254 can continue to maintain a weak suction force, and the activation time when the recording paper 150 is sucked again can be shortened.

  In the above-described embodiment, the control unit 258 controls the suction platen 550 based on the detection of the recording paper 154 by the sensors 536, 537, and 538, and the operation states of the plurality of recording heads 231 and 233. The case of controlling the suction platen 250 has been described. However, the control method by the control unit 258 is not limited to these.

  For example, in the ink jet recording apparatus 100, the conveyance amount of the recording paper 150 by the conveyance unit 210 is precisely controlled. Therefore, once the control unit 258 detects, for example, the leading end position of the conveyed recording paper 150, the control unit 258 can detect and control the leading end position of the recording paper 150 from the transport amount by the transport unit 210.

  FIG. 17 is a cross-sectional view schematically showing the structure and function of another suction platen 350 that can be used in place of the suction platen 250 shown in FIG. As shown in the figure, the suction platen 350 has a number of suction holes 259 on its upper surface. The lower ends of the suction holes 259 communicate with a plurality of decompression chambers 283 and 293 formed inside the suction platen 350, respectively.

  The decompression chambers 283 and 293 are coupled to a common suction fan 254 via ducts 285 and 295, respectively. The ducts 285 and 295 are provided with flaps 353 and 354 that are opened and closed by actuators 351 and 352, respectively. The suction fan 254 and the suction platen 350 are continuously operated throughout the operation period.

  In the suction platen 350 having the above structure, the suction fans 254 can be individually coupled to the decompression chambers 283 and 293 by opening and closing the flaps 353 and 354 by operating the actuators 351 and 352. That is, as shown in the figure, when the flap 353 communicates the duct 285 and the flap 354 closes the duct 295, the inside of one decompression chamber 283 is decompressed and the interior of the other decompression chamber 293 is not decompressed. Accordingly, in this state, the suction region 280 generates a suction force, while the suction region 290 does not generate a suction force.

  Thus, by forming the opening / closing valve by the flaps 353 and 354 and the actuators 351 and 352, the start and stop of suction in each of the suction regions 280 and 290 of the suction platen 350 can be speeded up. Therefore, suction can be started or stopped immediately in response to the arrival or withdrawal of the recording paper 150, 154. In addition, the suction fan 254 can continue to operate in a steady state, and wear and tear are reduced because it is avoided to repeatedly start and stop exhausted. Furthermore, since the suction fan 254 is operated steadily, the noise generated by the suction fan 254 is also reduced psychologically.

  FIG. 18 is a diagram schematically showing the structure of a suction platen 501 according to another embodiment. As shown in the drawing, the suction platen 501 has two suction regions 280 and 290 arranged along the conveyance direction M of the recording paper 154, similarly to the suction platen 250 shown in FIG. Further, the suction areas 280 and 290 have other suction areas 288 and 298 arranged in the width direction of the recording paper 154 orthogonal to the transport direction M, respectively.

  With such a structure, when the width of the recording paper 154 is narrower than the width of the suction platen 501, the suction of the suction areas 288 and 298 exposed to the side of the recording paper 154 can be stopped. Thus, when the width of the recording paper 154 is narrow, the airflow flowing into the suction holes 259 is prevented from disturbing the trajectory of the ink droplets ejected from the recording head 532 even in the vicinity of the side edge of the recording paper 154.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. Furthermore, it is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

1 is a perspective view illustrating an appearance of an ink jet recording apparatus 100 as viewed from the front. 1 is a perspective view illustrating an appearance of an inkjet recording apparatus 100 as viewed from the back. 2 is a perspective view showing an internal mechanism 200 of the ink jet recording apparatus 100. FIG. FIG. 4 is an enlarged view showing a part of a conveyance path 300 formed in an internal mechanism 200. 3 is a diagram schematically showing the structure of a suction platen 250. FIG. 5 is a plan view showing a layout of suction areas 280 and 290 in a transport path 300. FIG. FIG. 6 is a diagram schematically showing the operation of a suction platen 250. It is a figure which shows typically operation | movement of the suction platen 250 which concerns on another form. It is a figure showing typically operation of suction platen 250 concerning other forms. It is a figure which shows typically operation | movement of the suction platen 250 which concerns on another form. It is a perspective view which shows the external appearance of the inkjet recording device 400 which concerns on other embodiment. 2 is a perspective view showing an internal mechanism 500 of the ink jet recording apparatus 400. FIG. 6 is a diagram illustrating a conveyance path 600 of a recording sheet 154 in the internal mechanism 500. FIG. It is a figure which shows typically operation | movement of the suction platen 550. It is a figure which shows typically operation | movement of the suction platen 550 which concerns on another form. It is a figure showing typically operation of suction platen 550 concerning other forms. It is a figure which shows typically the structure of the suction platen 350 which concerns on another form. It is a figure which shows typically the structure of the suction platen 501 which concerns on another form.

Explanation of symbols

100, 400 Inkjet recording device, 110, 410 housing, 112 upper housing, 114 lower housing, 116 small housing, 120 legs, 130, 430 operation panel, 140 cartridge holder, 150, 154 recording paper, 152 , 552 roll, 160, 560 spindle, 200, 500 internal mechanism, 210, 510 transport unit, 212, 512 transport drive roller, 214, 514 transport driven roller, 216, 516 roller holder, 517 shaft, 220, 520 guide rail, 230, 530 Carriage, 231, 232, 233, 531, 532, 533 Recording head, 234, 534 Nozzle, 236, 237, 238, 239, 536, 537, 538, 539 Sensor, 240 Ink cartridge, 250, 350, 5 01, 550 Suction platen, 251 Platen body, 252 Guide surface, 253, 255 switch, 254, 284, 294 Suction fan, 256 Power supply, 258 Control unit, 259, 559 Suction hole, 280, 281, 288, 290, 291, 298, 580, 581, 590 Suction area, 283, 287, 293, 583, 587, 593 Decompression chamber, 285, 289, 295, 585, 589, 595 Duct, 300, 600 Transport path, 351, 352 Actuator, 353, 354 flap, 412 rear case, 414 recording unit case, 416 paper cartridge, 470 discharge tray, 518 discharge driven roller, 519 discharge drive roller

Claims (9)

A transport unit for transporting the recording medium in the transport direction;
A recording head that ejects ink toward a recording medium conveyed by the conveying unit;
A recording apparatus having a suction platen for forming a negative pressure on a surface and sucking a recording medium sent from the transport unit and positioning the recording medium at a position facing the recording head There,
The suction platen has a plurality of regions that individually generate a suction force with respect to the recording medium in the transport direction, and the target plate is in a region where the recording medium exists as the recording medium is transported. A recording apparatus that sucks a recording medium and restricts suction in an area where the recording medium does not exist.   The recording apparatus according to claim 1, wherein each of the plurality of areas individually includes suction means that individually operates or stops to generate or stop suction force.   The suction platen includes: a negative pressure source that is commonly used from the plurality of regions; and an open / close valve that individually connects or blocks each of the plurality of regions to the negative pressure source. The recording device described.   And a detection unit configured to detect an area where the recording medium is present on a surface of the suction platen based on an amount of the recording medium that has been conveyed after the conveyance unit has started conveying the recording medium. The recording apparatus according to 1.   The recording apparatus according to claim 1, further comprising a detection unit including a switch that is interrupted by the recording medium present on a surface of the suction platen.   The plurality of areas are also arranged in a direction intersecting the transport direction, and the recording medium is sucked in the area where the recording medium exists among the plurality of areas, and the recording medium exists. The recording apparatus according to claim 1, wherein suction is limited in a region where no recording is performed. A transport unit for transporting the recording medium in the transport direction;
A recording head that ejects ink toward a recording medium conveyed by the conveying unit;
A recording apparatus comprising a suction platen that forms a negative pressure on a surface and sucks and positions a recording medium fed from the transport unit at a position facing the recording head,
The suction platen includes a plurality of regions arranged in the transport direction and sucking the recording medium individually;
When the front end of the recording medium passes over the surface of the suction platen in the transport direction, the area where the recording medium exists is sequentially recorded from the upstream side in the transport direction. Aspirate the medium,
When the rear end of the recording medium in the transport direction passes over the surface of the suction platen, the area where the recording medium exists is sequentially sequentially detected from the upstream side in the transport direction. A recording apparatus that restricts suction to a recording medium. A transport unit for transporting the recording medium in the transport direction;
A liquid ejecting head that ejects liquid toward the recording medium transported by the transport unit;
A liquid jet including a suction platen that forms a negative pressure on the surface and sucks the recording medium fed from the transport unit and positions the recording medium at a position facing the liquid jet head A device,
The suction platen includes a plurality of regions that are arranged in the transport direction and individually generate a suction force with respect to the recording medium, and the recording medium is in a region where the recording medium exists among the plurality of regions. A liquid ejecting apparatus that restricts suction in an area where the recording medium does not exist. A transport unit for transporting the ejection medium in the transport direction;
A liquid ejecting head that ejects liquid toward the ejection target medium transported by the transport unit;
A liquid ejecting apparatus comprising: a suction unit that forms a negative pressure on a surface and sucks and positions a recording medium fed from the transport unit at a position facing the liquid ejecting head;
The suction unit has a plurality of regions for individually sucking the ejected medium in the transport direction;
When the front end of the ejection medium passes over the surface of the suction unit in the transport direction, the area where the ejection medium exists is sequentially ejected from the upstream side in the transport direction. Aspirate the medium,
When the rear end of the ejected medium passes over the surface of the suction platen with respect to the transport direction, the region where the ejected medium exists among the plurality of regions is sequentially applied from the upstream side with respect to the transport direction. A liquid ejecting apparatus that restricts suction to an ejecting medium.

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