JP2016221720A - Printer and platen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer capable of reliably performing a margin-less print, and suppressing stain on a rear surface of a sheet with an ink mist generated when the ink is discharged in the outside of a sheet end.SOLUTION: A platen includes a support part 14 for supporting the sheet, a suction part 17 having a first suction hole 18 for sucking the sheet to bring the same into contact with the support part, ink receiving parts 31A and 31B arranged adjacently to the support part in the sheet conveyance direction, and a second suction hole 180 for sucking air from a space between the sheet supported by the support part 14 and the ink receiving parts.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an inkjet printing apparatus including a platen that supports a sheet.

  Patent Document 1 discloses an ink jet printing apparatus capable of performing so-called “marginless printing” in which an image is formed without providing a margin at an end of a sheet. This apparatus uses a suction platen that adsorbs a sheet by negative pressure.

JP 2006-021475 A

  In Patent Document 1, when performing borderless printing on the trailing edge of the sheet, the sheet is adsorbed to the adsorption portion of the platen. However, when performing borderless printing on the leading edge of the sheet, the leading edge of the sheet has not yet reached the suction portion and is not sucked. For this reason, when the sheet is introduced, the lifting of the leading edge of the sheet cannot be suppressed, and the ink is landed while the sheet is lifted. As a result, there is a possibility that the image quality at the raised portion is deteriorated, or the sheet comes into contact with the print head and the sheet becomes dirty. Furthermore, ink that is discarded outside the edge of the sheet during borderless printing may float as a mist-like ink mist and adhere to the back surface of the sheet.

  The present invention provides a printing apparatus and a platen capable of reliably performing borderless printing and suppressing the back surface of the sheet from being stained with ink mist generated when ink is ejected to the outside of the sheet edge. For the purpose of provision.

  An embodiment of the present invention that solves the above-described problem is a printing apparatus that includes a print head that ejects ink and a platen that supports the sheet so as to face the print head, and the platen supports the sheet. A support part, a first suction hole provided in the support part, for sucking the sheet so as to adsorb the sheet on the support part, and provided adjacent to the support part and supported by the support part An ink receiving portion that receives ink ejected from the print head on the outside of the sheet, and a second suction hole that sucks air from a space between the sheet supported by the support portion and the ink receiving portion. It is characterized by that.

  According to the present invention, it is possible to reliably perform borderless printing, and it is possible to suppress contamination of the back surface of the sheet with ink mist generated when ink is ejected outside the sheet edge.

FIG. 2 is a perspective view illustrating an appearance of the printing apparatus. 1 is a perspective view illustrating an overall configuration of a printing apparatus main body. It is a vertical side view of a printing apparatus. It is a perspective view which shows a platen and its peripheral structure. It is the perspective view which looked at the platen and its peripheral structure from the bottom side. It is the perspective view which showed a platen and a part of sheet | seat. It is a perspective view which shows the flow of the air in a platen. It is sectional drawing which follows the VII-VII 'line | wire in FIG. It is a top view of a platen. It is a perspective view which shows 2nd Embodiment. It is a perspective view which shows the modification of 2nd Embodiment. It is a top view of FIG. It is a perspective view which shows another modification of 2nd Embodiment. It is a top view / sectional view showing another modification of a 2nd embodiment. It is sectional drawing which shows the modification of 1st / 2nd embodiment. It is sectional drawing which shows another modification. It is sectional drawing which shows the modification of 1st Embodiment. It is sectional drawing which shows the modification of 2nd Embodiment.

  An embodiment of a printing apparatus according to the present invention will be described. Hereinafter, an example of a serial type inkjet printing apparatus that performs printing by reciprocating a print head capable of ejecting ink in a direction intersecting the sheet conveyance direction with respect to a sheet intermittently conveyed in a certain direction will be described. To do. The present invention is not limited to a serial type printing apparatus, but can be applied to a line printing apparatus that performs continuous printing using a long print head. The printing apparatus is not limited to a single-function printing apparatus, but can be applied to a multifunction printer having both a copy function and a facsimile function.

  FIG. 1 is a perspective view illustrating an appearance of a printing apparatus according to an embodiment. A front side of the printing apparatus 1 is provided with a discharge tray 12 that supports printed sheets, and an operation unit 1a and a display unit 1b for performing various setting operations. Further, an upper surface cover 1c covering an internal structure such as a carriage described later is provided on the upper surface portion of the printing apparatus 1 so as to be openable and closable. A feeding tray 40a is provided to be openable and closable. Although FIG. 1 shows a state in which the discharge tray 12 and the feeding tray 40a are closed, it is possible to open both trays 12 and 40a as shown in FIG.

  Here, the configuration of the printing apparatus main body 1A will be described with reference to FIGS. FIG. 2 is a perspective view showing an overall configuration of a printing apparatus main body 1A obtained by removing an exterior portion from the printing apparatus 1, and FIG. 3 is a longitudinal side view of the printing apparatus 1A shown in FIG.

  A feeding device 40 is provided on the back side of the printing apparatus main body 1A. The feeding device 40 separates the sheets one by one from the bundle of cut sheets (hereinafter simply referred to as “sheets”) stacked on the feeding tray 5 by the rotation of the feeding roller 6, and transport means such as the transport roller 7. To feed. The printing apparatus main body 1A is provided with a carriage 4 on which a print head 3 capable of ejecting ink is mounted. The carriage 4 is supported so as to be capable of reciprocating along a carriage guide shaft 41 and a carriage rail 42 provided along a direction (X direction) intersecting (orthogonal in the embodiment) with respect to the sheet conveyance direction (Y direction). Has been. The movement of the carriage 4 and the print head 3 along the X direction is also referred to as scanning in the following description. The X direction is the carriage movement direction and also the sheet width direction of the conveyed sheet. The Y direction is the sheet conveying direction.

  One sheet separated and fed by the feeding device 40 from a bundle of sheets stacked on the feeding tray 40a is printed by a first conveying roller pair (conveying means) composed of a conveying roller 7 and a pinch roller 8 by a print head. 3 is conveyed onto a platen 9 that supports a sheet at a position opposite to the platen 9. Here, the carriage 4 on which the print head 3 is mounted moves in the X direction, and ink is ejected from the print head 3 toward the sheet. A sheet detection sensor for detecting the end of the sheet is provided on one side surface of the carriage 4. Based on the detection output from the sheet detection sensor, the relative position between the sheet and the print head and the start of printing on the sheet are provided. Timing is determined.

  When printing for one scan is performed on the sheet, the sheet is conveyed by a predetermined amount in the Y direction orthogonal to the X direction by the first conveying roller pair. By repeating the scanning of the print head 3 and the conveyance of the sheet, printing on the sheet is performed in a serial manner.

  The sheet 2 on which printing has been completed is placed on the discharge tray 12 by a second conveyance roller pair (conveyance means) including a discharge roller 10 and a spur 11 that is disposed downstream of the platen 9 in the sheet conveyance direction (Y direction). Discharged.

  Next, the configuration of the platen in the first embodiment will be described. 4 is a perspective view showing the platen and its peripheral structure, and FIG. 5 is a perspective view of the platen and its peripheral structure shown in FIG. 4 as seen from the bottom side.

  The structure of the platen 9 used in the printing apparatus 1 will be described. As shown in FIGS. 3 and 4, the platen 9 is disposed between the first conveyance roller pair including the conveyance roller 7 and the pinch roller 8 and the second conveyance roller pair including the discharge roller 10 and the spur 11. Has been. The platen 9 is provided at a position facing the discharge port forming surface 3a of the print head 3 in which discharge ports for discharging ink are arranged. The platen 9 supports the surface (back surface) opposite to the print surface facing the discharge port forming surface 3a (see FIG. 2) of the sheet 2 conveyed by the first and second conveyance roller pairs.

  FIG. 4 is a perspective view of the platen shown in FIG. 1 as viewed obliquely from above. In FIG. 4, the platen 9 has a sheet support portion 14 (which can support the back surface of the sheet 2 while suppressing the floating and bending of the sheet 2 in order to keep the gap between the discharge port forming surface 3 a of the print head 3 and the sheet 2 appropriate. 1st support part) is formed. The sheet support portion 14 is configured to be divided into a plurality of regions along the longitudinal direction (X direction) of the platen 9 corresponding to a plurality of types of sheet width sizes.

  Specifically, for a plurality of standard size sheets, the sheet support portion 14 is provided so as not to be positioned within a range of about 2 mm from the sheet side edge when each sheet is conveyed. The platen 9 of this embodiment corresponds to the sheet width of sheets such as L size, KG, 2L size, six cuts, Letter, A4, four cuts, A3, A3 novi, half cut, A2, A2 nobi, 17 inches, etc. The arrangement and shape of the sheet support portion 14 are determined.

  6 and 7 are enlarged perspective views showing the detailed shape of the sheet support portion 14. The sheet support portion 14 is formed by forming a rib-like convex portion having a flat sheet support surface 13 in contact with the back surface of the sheet into a rectangular frame shape. An adsorption recess 17 (suction part) that is one step lower than the sheet support surface 13 is formed on the upper part of the sheet support part 14. The suction recess 17 is provided with a suction hole 18 (first suction hole) penetrating from the front surface to the back surface. The suction recess 17 is provided with a suction hole 18 penetrating from the front surface to the back surface. The suction hole 18 communicates with the negative pressure generating means 19 through a plurality of first negative pressure chambers 22 formed by the outer peripheral wall 20 of the platen 9 and a duct 27 (see FIG. 5) connected thereto. A negative pressure generated by the negative pressure generating means 19 is applied to the first negative pressure chamber 22 and the suction port 18.

  Further, in order to prevent the sheet from falling into the suction recess 17, the suction recess 17 is provided with an intermediate rib 14 r having the same height as the sheet support surface 13. The surface of the intermediate rib 14r is preferably continuous with the sheet support surface 13 and extends in the sheet conveyance direction (Y direction).

  An ink receiving portion that receives the ink discharged to the outside of the sheet 2 is formed around the sheet support portion 14. In order to reliably perform so-called borderless printing in which printing is performed on the entire sheet without providing margins at the periphery of the sheet, it is necessary to eject ink to the outside from the end of the sheet. In addition, in the ink jet printing apparatus, so-called preliminary ejection, in which ink is ejected to the outside of the sheet immediately before the printing operation, is performed in order to stabilize the ink ejection performance of the print head 3. The ink ejected to the outside of such a sheet is received by an ink receiving portion formed on the platen 9.

  As shown in FIGS. 6 and 7, as the ink receiving portion, the front end ink discarding groove 31A for receiving the ink discharged outside the sheet leading end 2a and the after the ink discharged outside the sheet trailing end 2b are received. An end ink discarding groove 31B is provided. The leading-edge ink discarding groove 31A is elongated in the X direction adjacent to the downstream side of the sheet support portion 14, and the trailing-edge ink discarding groove 31B is elongated adjacent to the upstream side of the sheet support portion 14. It extends in the X direction. As the ink receiving portion, left and right end ink discarding grooves 34 for receiving the ink ejected from the left and right ends (sheet side ends) of the sheet 2 in the sheet width direction are further provided. The left and right end ink discard grooves 34 extend in the Y direction and connect the upstream ink discard groove 31B and the downstream ink discard groove 31A.

  In this way, assuming that borderless printing is performed on the four sides of the cut sheet, the leading edge ink discarding groove 31A, the trailing edge ink discarding groove 31B, and the left and right end ink discarding grooves 34 are used. An ink receiving portion is provided. Each sheet support portion 14 has a shape like an isolated island surrounded by the ink receiving portion.

  An ink absorber 35 is disposed in each ink discarding groove in the ink receiving portion so as to receive the ejected ink and hold the received ink without leaking. The material of the ink absorber 35 is preferably composed of a single sponge-like sheet material such as urethane foam. By forming the ink absorber 35 with such an ink-absorbing material, the ink from the print head 3 can be reliably received, and the received ink can be permeated into the interior and guided to the ink discharge port. Is possible.

  Also, some of the ink discarded outside the sheet 2 becomes a mist-like ink mist and floats in the air. Therefore, in order to suck and collect the ink mist, as shown in FIGS. 6 and 7, a second suction hole 180 which is a slit hole is provided in the bottom surface portion of the left and right end ink discarding grooves 34. The second suction hole communicates with the suction fan 19 as the negative pressure generating means via the first negative pressure chamber 22 and the duct 27 described above, from which mist is sucked and collected. The slit hole of the second suction hole 180 has a shape elongated in the sheet conveying direction. The second suction hole 180 is provided at a position (ink receiving part) lower than the sheet support part 14 with respect to the suction hole 18 (first suction hole) provided on the sheet support part 14. The second suction hole 180 sucks air from the space between the sheet supported by the sheet support portion 14 and the ink receiving portion.

  6 is a perspective view showing a part of the platen and the sheet, and FIG. 7 is a perspective view showing a flow of air in the platen shown in FIG. 6 and 7, an upstream sheet support portion 32 that supports the sheet 2 conveyed from the conveyance roller 7 from the back surface is formed further upstream of the ink discard groove 31B for the rear end of the platen 9. ing. Further, a downstream sheet support portion 33 that supports the sheet conveyed by the discharge roller 10 from the back surface is formed further downstream than the ink discard groove 31A for the front end of the platen 9. Both the upstream sheet support portion 32 and the downstream sheet support portion 33 are formed by ribs extending along the sheet conveyance direction (Y direction), and a plurality of the sheet support portions 32 and the downstream sheet support portions 33 are arranged in the X direction at regular intervals. Has been.

  Assuming that the plurality of sheet support portions 14 are “first support portions”, the upstream sheet support portion 32 and the downstream sheet support portion 33 can be regarded as “second support portions”. The second support unit supports the sheet away from the first support unit in the sheet conveyance direction.

  The upstream sheet support part 32 and the downstream sheet support part 33 are formed so that the positions of the tops thereof are the same height as the sheet support surface (contact part) 13 of the sheet support part 14 described above. The upstream sheet support portion 32 and the downstream sheet support portion 33 prevent the sheet 2 from dropping or getting caught when the leading end or the trailing end of the sheet 2 passes through the sheet supporting portion 14 or each roller. At the same time, it fulfills the function of forming a communication path described later.

  In addition, the plurality of upstream side seat support portions 32 are connected to each other by a connection seating surface 37 at each lower portion (see FIGS. 6, 7, and 9), and between the seat and the connection seating surface 37. A gap is formed between them. Similarly, the downstream seat support portions 32 are connected to each other by the connection seat surface 37, and a gap is formed between the seat 2 supported by the downstream seat support portion 32 and the connection seat surface 37. .

  The platen 9 is manufactured as one part by a resin mold. The sheet support part 14, the upstream sheet support part 32, the downstream sheet support part 33, the first negative pressure chamber 22, and the ink receiving part are all formed in one resin mold part constituting the platen 9. . This simplifies the manufacturing of the printing apparatus and improves the relative positional accuracy of the functional units.

  In this configuration, the sheets 2 stacked on the feeding tray 5 are fed to the conveyance roller 7 by the above-described feeding device 40 and further conveyed to the platen 9 by the conveyance roller 7. Here, the suction fan 19 is activated while the sheet 2 is being fed, and a predetermined negative pressure is generated in the duct 27 communicating with the suction hole 18 of the platen 9.

  Prior to the start of the printing operation, the sheet 2 has a position where the leading edge 2a of the sheet 2 extends beyond the ink discard groove 31 of the upstream sheet support portion 32 and reaches the sheet support portion 14 and then slightly protrudes from the downstream end 14b ( It is transported to the cue position). During this conveyance operation, since negative pressure is generated in the suction recess 17, the leading end 2 a of the sheet 2 is conveyed while being sucked toward the support surface 13. Therefore, the sheet 2 can be prevented from floating at the tip 2a.

  From the state where the sheet is conveyed to the cueing position, the print head 3 reciprocates and starts printing according to the image data. When performing borderless printing on the leading edge of the sheet, an image is printed on the sheet 2 and ink is ejected to an area outside (downstream) the leading edge of the sheet 2. The ink ejected to the area outside the sheet 2 is discarded by the ink absorber 35 in the rear end ink discarding groove 31 </ b> B located downstream from the sheet support portion 14. After completion of borderless printing on the leading edge 2 a of the sheet 2, printing is continued while repeating conveyance of the sheet by the conveyance roller 7 and the discharge roller 10 and reciprocating scanning of the print head 3.

  When performing borderless printing on the left and right edges (sheet side edges) of the sheet, ink is ejected onto the sheet 2 in the state shown in FIGS. Ink is ejected. The platen 9 is also formed with left and right end ink discarding grooves 34 corresponding to the positions of the left and right ends of the sheet 2, and the ink ejected outside the left and right ends of the sheet 2 is outside the left and right ends of the sheet 2. The ink absorber 35 in the left and right end ink discard grooves 34 located at

  When printing is continued and the trailing edge of the sheet 2 passes between the first conveyance roller pair (conveyance roller 7 and pinch roller 8), the sheet is then conveyed by the second conveyance roller pair (discharge roller 10 and spur 11). 2 is carried. When the rear end 2b of the sheet 2 is conveyed to a position protruding slightly upstream from the sheet support portion 14, borderless printing on the rear end 2a of the sheet 2 is performed. Here, ink is ejected onto the sheet 2 as well as borderless printing on the leading edge 2a of the sheet 2, and ink is also ejected to an area outside (upstream) from the rear end 2b of the sheet 2. The ink ejected to the area outside the rear end 2b of the sheet 2 is discarded by the ink absorber 35 (sponge) in the rear end ink discard groove 31B located on the upstream side of the sheet support portion 14. In this manner, the printing on the rear end 2b of the sheet 2 is also completed in a state where the sheet 2 is attracted to the sheet support surface 13.

  As described above, since the sheet 2 is always on the sheet support surface 13 of the sheet support part 14 from the start to the end of printing, the sheet 2 is always supported by introducing an appropriate negative pressure to the suction recess 17. Printing can be performed while adsorbed on the surface 13. For this reason, the distance between the print head and the sheet can be maintained at a predetermined appropriate distance, and an image can be printed accurately. Since the carriage 4 is provided with a sensor for detecting the end of the sheet, the end of the sheet can be accurately arranged at the apex of the rib by the detection of the sensor.

  As shown in FIG. 6, when the sheet 2 is in contact with the upstream sheet support portion 32 and the downstream sheet support portion 33, the sheet 2 is surrounded by the sheet support portion 14, the leading-edge ink discarding grooves 31A and 31B, and the sheet. A space area AR is formed. However, the space area NA communicates with the gap formed between the connection seat surface 37 and the seat 2 as described above, and this gap constitutes a communication path that communicates the space area NA with the outside. . In addition, since the second suction hole 180 is formed in the space area NA, the pressure in the space area AR is lower than that of the surrounding area and is negative. Therefore, as shown in FIG. 8, air is supplied to a low pressure space area (hereinafter referred to as negative pressure part) NA through the communication path.

  As a result, the air flow F1 that is about to flow into the gap between the sheet 2 and the sheet support surface 13 from the end portion (2d in the drawing) of the sheet 2 flows from the end portion 2d of the sheet 2 to the second suction hole 12. Significant decrease compared to F2. As a result, it is possible to suppress the ink mist from flowing around and adhering to the back side of the sheet 2 during borderless printing.

  Further, by supplying air to the negative pressure portion S1, the pressure of the negative pressure portion NA increases (the negative pressure decreases), and the pressure difference between the negative pressure portion NA and the periphery of the end 2d of the seat 2 Becomes smaller. Thereby, the speed of the airflow F3 in the peripheral part of the end part 2d of the sheet 2 is reduced. For this reason, it is possible to reduce the deviation of the landing position of the print head due to the influence of the air flow F3, and it is possible to suppress the deterioration of the image quality in the peripheral portion of the right end 2d of the sheet 2. Although FIG. 8 shows the right end 2d of the sheet 2, the same effect can be obtained for the left end 2c of the sheet 2.

  If the upstream sheet support part 32 and the downstream sheet support part 33 of the ink receiving part are not formed by a plurality of ribs as in this embodiment, but have a flat shape, the following phenomenon occurs. . That is, among the airflows flowing into the second suction holes 180 located immediately below the sheet end 2d, the flow resistance of the airflow flowing from the upstream side and the downstream side in the sheet conveying direction (Y direction) is the width direction of the sheet ( It becomes larger than the flow resistance of the air flow flowing in from (X direction). Therefore, the airflow from the outside to the second suction hole 180 has a significantly larger airflow rate in the sheet width direction (X direction) than the airflow rate in the sheet conveyance direction (Y direction). That is, the amount of air flowing into the second suction hole 180 is governed by the airflow in the sheet width direction.

  At this time, air is also sucked in the suction hole (181 in FIG. 8) formed in the suction recess 17 of the ink support portion 14 located outside the sheet end 2d. Most of the air outside the sheet end 2d flows into the suction hole 181, and the amount of air flowing from the outside of the sheet end 2d into the suction hole 180 located immediately below the sheet end 2d is very small. As a result, the air flow from the sheet end 2d to the second suction hole is strengthened, and accordingly, the velocity of the air flow from the center of the sheet toward the sheet end 2d increases around the end of the sheet. Then, the ink ejected near the sheet edge 2d is caused to flow under the force of the airflow, the landing position is shifted, and the phenomenon that the image quality formed near the sheet edge 2d is deteriorated occurs. In particular, when the image to be printed includes a ruled line, the line width becomes thick, and the deterioration of the image quality is easily visually recognized.

  Here, if the mist suction force in the second suction holes 180 provided in the left and right end ink discarding grooves 34 is reduced, it is possible to suppress the deterioration of the image in the peripheral portion of the end portion of the sheet. However, in this case, the air flow F2 from the sheet end portion 2d to the second suction hole 180 is weakened, and the air flow flowing into the gap between the sheet 2 and the sheet support surface 13 is increased. It becomes easy to be transported to the back side of. As a result, ink mist adhering to the back surface of the sheet increases.

  As described above, when the upstream and downstream sheet support portions 32 and 33 are formed in a flat shape, there is a trade-off relationship between the reduction of the stain on the back surface of the sheet due to the ink mist and the suppression of the image quality deterioration at the sheet edge. It is difficult to realize both at the same time.

  On the other hand, according to the present embodiment, since the communication path for supplying air to the negative pressure portion NA is formed, the dirt on the sheet 2 due to the ink mist is reduced, and the image quality around the edge of the sheet is reduced. It is possible to achieve both suppression of deterioration of the material.

(Modification)
FIG. 10 is a diagram illustrating the second embodiment. The downstream sheet support portion is formed by a wall portion 330 formed along the sheet width direction (X direction) on the outer side (downstream side) of the front end ink discarding groove 31A. Further, the upstream sheet support portion is formed by a wall portion 320 formed along the sheet width direction (X direction) on the outer side (upstream side) of the trailing edge ink discarding groove 31B. In the walls 320 and 330, communication passages 260 and 261 each including a through hole are formed along the sheet conveyance direction (Y direction).

  The communication path 260 communicates with the rear end ink discarding groove 31B, one opening 270 is formed at a position communicating with the rear end ink discarding groove 31A, and the other opening 280 is formed with the front end ink discarding groove 31A. It is formed on a surface (outer surface) that is further separated in the sheet conveyance direction. The communication path 261 communicates with the rear end ink discarding groove 31A, one opening 271 is formed at a position communicating with the rear end ink discarding groove 31A, and the other opening 281 is disposed at the front end ink discarding groove 31A. It is formed on a surface (outer surface) that is separated from the groove 31A in the sheet conveyance direction.

  FIG. 11 (perspective view) and FIG. 12 (plan view) are diagrams showing different variations of the second embodiment. The platen 9 has communication passages 260 and 261 having openings 270 and 271 at positions where the side surface of the support portion 14 that supports the end portion of the sheet 2 intersects a surface that extends in the sheet conveyance direction (Y direction). Provided. Most of the air supplied to the negative pressure part NA passes through the communication passages 260 and 261. The communication path so that the first openings 270 and 271 are arranged at positions where the side surface of one support portion 14 on the same side as the end portion of the sheet 2 intersects a surface 14F extending in the sheet conveyance direction. 260 and 261 are arranged.

  FIG. 13 is a diagram showing another variation of the second embodiment. The communication path 260 is formed only in the upstream wall 320, that is, in the wall 320 formed along the rear end ink discarding groove 31B, and is not provided in the downstream wall. That is, no communication path is formed in the wall 330 formed along the ink discarding groove 31A on the front end side. Here, the communication path 260 has an opening 270 at a position facing the negative pressure part NA and the spur roller 11 (see FIG. 3). Conversely, the communication path may be provided only on the downstream wall 330 and not on the upstream wall 320. By forming the communication path in the wall portion on either the upstream side or the downstream side of the platen, it is possible to achieve both the reduction of the dirt on the sheet 2 and the suppression of the deterioration of the image quality.

  FIG. 14 is a diagram showing another variation of the second embodiment. One of the openings of the communication path 260 is formed on the back surface of the platen 9. Ink mist generated by printing may not be completely recovered only by suction from the second suction hole 180 and may float in the space above the platen 9 in the printing apparatus. It is desirable that the air supplied to the negative pressure part 16 through the communication path 260 is not contaminated with mist. Therefore, in FIG. 14, one opening 280 of the communication path 260 is disposed on the back surface of the platen 9.

  FIG. 15 is a diagram illustrating a modification of the first embodiment and the second embodiment described above. When the sheet 2 having a certain sheet width is sucked and held, the suction at the suction hole 18 in the sheet support portion 14 that is not covered with the sheet is stopped. With respect to the suction holes 18 provided at a plurality of different positions in the sheet width direction, suction is individually controlled according to the sheet width of the sheet to be used. As a means for stopping the suction in the sheet support portion 14, a valve 250 that switches communication and blocking of the suction hole 18 is provided under the sheet support portion 14. As for the seat support portion 14 on the outer side of the seat, the suction hole 18 provided in the convex portion is closed by moving the valve 250 upward as shown in FIG. On the other hand, when the valve 250 moves downward, a negative pressure is supplied to the seat support portion 14. By stopping the suction of the sheet support part 14 located outside the sheet, it is possible to supply more from the outside to the negative pressure part NA.

  FIG. 16 is a diagram showing still another modification. The second suction hole 180 is formed along the side wall of the sheet support portion 14 that holds the sheet 2 by suction rather than immediately below the sheet 2. As a result, it is possible to prevent the ink discarded in the left and right end ink discarding grooves 34 from adhering to the second suction holes 12 and solidifying to reduce the amount of ink mist recovered. Furthermore, compared with the case where the second suction hole 180 is provided directly below the end portion of the sheet 2, the second suction hole 180 extends from the periphery of the end portion of the sheet 2 along the side wall of the sheet support portion 14. More air is supplied.

  FIG. 17 is a diagram showing still another modification. In the first embodiment (FIG. 6), a plurality of communication paths formed between the upstream sheet support portions 32 and the downstream sheet support portions 33 and the common pressurizing means 220 are connected to the plurality of flow paths. In addition to being connected by a channel 240, a valve 230 is provided in each channel 240. In order to adjust the flow rate of air supplied from the pressurizing means 220 to the negative pressure unit 16, the opening / closing control or the opening degree control is individually performed on the plurality of valves 230. Specifically, the plurality of valves 230 are controlled according to the sheet width of the sheet to be used. The pressurizing means 220 and the plurality of valves 230 constitute an air supply means of an active individual pressurizing mechanism.

  FIG. 18 is a diagram showing still another modification. This is an example in which an active individual pressurizing mechanism is provided in the previous second embodiment (FIGS. 10 to 14). The communication path formed in the wall part 320 and the pressurizing means 22 are connected via a plurality of flow paths 240, and each is provided with a valve 230, and the flow rate of air supplied by adjusting the valve 230 individually is adjusted. As described above, the examples in FIGS. 17 and 18 are provided with means for individually supplying air to each of the communication paths provided at a plurality of different positions in the sheet width direction.

  According to the embodiment that has been described above, it is possible to perform printing without a four-sided border on a cut sheet. In addition, it is possible to reliably perform borderless printing, and it is possible to suppress the back surface of the sheet from being stained with ink mist generated when ink is ejected to the outside of the sheet edge.

2 Sheet 3 Print head 9 Platen 14 Support part 18 Suction hole (first suction hole)
32 Upstream seat support (second support)
33 Downstream sheet support part (second support part)
180 Second suction hole

Claims (13)

A printing apparatus comprising: a print head that ejects ink; and a platen that supports a sheet facing the print head,
The platen is
A support for supporting the sheet;
A first suction hole that is provided in the support portion and sucks the sheet onto the support portion;
An ink receiving portion that is provided adjacent to the support portion and receives ink ejected from the print head on the outside of the sheet supported by the support portion;
A second suction hole for sucking air from a space between the sheet supported by the support portion and the ink receiving portion;
A printing apparatus comprising: A second support part for supporting the sheet away from the support part in the sheet conveying direction;
The printing apparatus according to claim 1, wherein the second support portion is provided with a communication path for introducing air into the space in a state where the sheet is supported.   The second support portion has a structure in which a plurality of ribs extending in the conveyance direction are arranged side by side in the sheet width direction, and the communication path is formed between the adjacent ribs. The printing apparatus according to claim 2.   The printing apparatus according to claim 2, wherein the second support portion includes a wall portion extending in a sheet width direction, and the communication path including a through hole is formed in the wall portion. .   The second support part is provided upstream and downstream of the support part as a part of the platen, and the communication path is provided in at least one of the second support part upstream and downstream. The printing apparatus according to claim 2, wherein:   The plurality of support portions are arranged side by side in the sheet width direction, and the second suction hole is provided between the adjacent support portions. The printing apparatus as described in any one.   The printing apparatus according to claim 6, wherein the second suction hole is a slit hole extending in a sheet conveyance direction.   The printing apparatus according to claim 7, wherein the slit hole is provided at a position covered under a sheet side end of a sheet on which borderless printing is performed.   9. The printing apparatus according to claim 6, wherein when viewed from above, each of the plurality of support portions is surrounded and isolated by the ink receiving portion.   The second suction hole is provided at a plurality of different positions in the sheet width direction, and suction is controlled individually according to the sheet width of the sheet to be used. The printing apparatus according to one item.   The said communicating path is provided in several different positions in the sheet | seat width direction, It has a means to pressurize and supply air separately with respect to each said communicating path, The any one of Claim 2 to 5 characterized by the above-mentioned. The printing apparatus according to one item.   The said support part, the said 2nd support part, and the said ink receiving part are collectively formed in one resin mold component which comprises the said platen, The any one of Claim 2 thru | or 11 characterized by the above-mentioned. The printing apparatus according to one item. A platen disposed opposite to a print head that ejects ink,
A support for supporting the sheet;
A first suction hole provided in the support portion for sucking the sheet so that the sheet is adsorbed on the support portion;
An ink receiving portion that is provided adjacent to the support portion and receives ink ejected from the print head on the outside of the sheet supported by the support portion;
A second suction hole for sucking air from a space between the sheet supported by the support portion and the ink receiving portion;
A platen characterized by comprising: