JP2015027751A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet printer that securely recovers ink discarded in borderless printing, reduces staining of a sheet, and balances an image print of high quality.SOLUTION: A platen is provided with a reception part which receives ink jetted by an ink jet head to outside a sheet, and the reception part has a long hole which is applied with negative pressure and a guide part which guides the received ink to a predetermined part of the long hole. The long hole has a slit part which includes the predetermined part as its end and extends downstream in a conveying direction of the sheet, and the guide part is so shaped as to restrict the received ink from flowing into the slit part.

Description

  The present invention relates to a structure of an ink receiving portion provided on a platen for borderless printing in an inkjet printing apparatus.

  Borderless printing is known in which printing is performed without providing a margin at the end of the sheet. The printing apparatus disclosed in Patent Document 1 is provided with an ink receiving portion (edgeless groove) on the platen in order to collect the ink that protrudes outside the end portion of the sheet and is ejected from the inkjet head. . The ink receiving portion is provided with a suction hole for supplying a negative pressure. By sucking through the suction holes, the received ink is collected and the ink mist generated along with the ink ejection is collected. Thereby, it can reduce that ink mist adheres to the back side of a sheet, and becomes dirty.

JP 2006-231612 A

  In an ink jet printing apparatus, how to reduce the contamination of the sheet and in-machine due to ink mist is a major issue. In general, more ink mist can be recovered by increasing the negative suction pressure. However, as the negative pressure increases, the ink droplets ejected from the inkjet head are attracted toward the suction hole during the flight. As a result, the positional accuracy of ink landing on the sheet at the sheet edge is lowered, leading to a reduction in image quality at the sheet edge.

  The present invention has been made based on recognition of such problems. An object of the present invention is to enable reliable collection of discarded ink, reduction of sheet contamination due to ink mist, and high-quality image printing at a high level in an inkjet printing apparatus capable of borderless printing. The provision of a platen mechanism.

  The present invention is a printing apparatus including a platen that supports a sheet printed by an inkjet head, and the platen is provided with a receiving portion that receives ink that has been struck outside the sheet by the inkjet head. In the receiving portion, a long hole to which negative pressure is supplied and a guide portion for guiding the received ink to a predetermined portion of the long hole are formed. The long hole has an end portion at the predetermined portion. And the guide part has a shape that restricts the received ink from flowing into the slit part.

  According to the present invention, in a printing apparatus capable of borderless printing, reliable collection of discarded ink, reduction of sheet contamination due to ink mist, and high-quality image printing can be balanced at a high level. .

1 is an overall configuration diagram of an inkjet printing apparatus according to an embodiment. The figure which shows the structure of a platen. The figure explaining the effect | action of ink collection | recovery. The figure explaining the effect | action of sheet | seat dirt reduction. The figure which shows the modification of a guidance | induction part. The figure which shows another modification of a guidance | induction part. The figure which shows the modification of a long hole. The figure which shows another modification of a long hole. The figure which shows the modification of a support rib.

  Hereinafter, embodiments of the present invention will be exemplified. However, the configuration described in the present embodiment is merely an example, and does not limit the scope of the invention.

  1A and 1B show an overall configuration of an ink jet printing apparatus according to the present embodiment. FIG. 1A is a perspective view and FIG. 1B is a side view.

  The printing apparatus 100 is roughly composed of three units: a supply unit that supplies sheets, a conveyance unit that conveys sheets, and a printing unit that prints on sheets.

  The supply unit includes a spool 18 to which the sheet 3 on which a continuous sheet is wound in a roll shape is attached, and a torque limiter 19 that restricts the rotation of the spool 18. The spool 18 includes flanges 18a and 18b fitted to both ends of the seat 3, and a shaft 18c for connecting the flanges 18a and 18b. Since the spool 18 is fixed to the sheet 3 by the flanges 18a and 18b, the spool 18 also rotates in accordance with the rotation of the sheet 3. The torque limiter 19 is provided to brake the rotation of the spool 18.

  The conveyance unit includes a conveyance roller 11, a pinch roller 16, a belt 12, a conveyance motor 13, a rotary encoder 14, and a reading unit 15. The sheet 3 supplied from the supply unit is nipped by the conveyance roller 11 and the pinch roller 16 and conveyed to the printing unit. The conveyance roller 11 is driven by a conveyance motor 13 via a belt 12. The conveyance accuracy of the conveyance roller 11 is guaranteed by causing the reading unit 15 to read the pattern of the rotary encoder 14. The detection method of the pattern and the reading unit 15 may be optical, magnetic, or mechanical.

  The print unit includes a housing 1, a platen 2, a main rail 5, a carriage 6, an inkjet head 7, a carriage motor 8, a belt 9, and a linear encoder 10. The carriage 6 reciprocates along the main rail 5 provided parallel to the axial direction of the transport roller 11. An ink jet head 7 is mounted on the carriage 6, and ink is ejected from the nozzles of the ink jet head 7 toward the sheet 3 conveyed by the conveying roller 11 to perform recording on the sheet. The ink jet head 7 may use any ink jet system such as a system using a heating element or a system using a piezo element. The carriage 6 is driven by a carriage motor 8 via a belt 9. The operation accuracy of the carriage 6 is ensured by causing the reading unit (not shown) to read the pattern of the linear linear encoder 10.

  A platen 2 that supports a sheet during printing is provided at a position facing the carriage 6. Under the platen 2, a housing 1 for supporting the platen 2 is provided. Further, the platen 2 communicates with the negative pressure generating unit 4 in order to generate a negative pressure at the suction part of the platen 2. The negative pressure generator 4 is a sirocco fan or the like. The negative pressure generator 4 is provided inside the housing 1. A space surrounded by the platen 2 and the negative pressure generator 4 is maintained at a negative pressure. The platen 2 is divided into three in the reciprocating direction of the carriage, and is assumed to be platens 2a, 2b, and 2c from the right in FIG. The structure of the platen 2 is a feature of the present embodiment, and details will be described later.

  Next, a series of printing operations will be described. First, the user pulls out the leading end of the sheet 3 mounted on the spool 18 and pushes the leading end of the sheet in the J direction. The leading edge of the sheet is guided to the conveyance roller 11 along the sheet path. When the leading edge of the sheet reaches the roller pair of the conveyance roller 11 and the pinch roller 16, the conveyance roller 11 starts to be driven, and the sheet 3 is conveyed onto the platen 2. The direction transported at this time is defined as “transport direction” (K direction in FIG. 1B). The sheet 3 conveyed on the platen 2 is adsorbed by the platen 2. The attracting force at this time is not strong, and is weak enough to prevent the sheet from being lifted and to convey the sheet. Printing is performed by reciprocating an inkjet head 7 mounted with a carriage 6 on the sheet 3 adsorbed on the platen 2.

The structure of the platen will be described with reference to FIG. Although the platen 2 is divided into three platens 2a, 2b and 2c, there is no difference in the basic structure of any unit. Hereinafter, description will be made using the platen 2a.
FIG. 2A is a view of the platen 2a as viewed from above. On the surface of the platen 2a, a sheet adsorbing portion 23 (adsorbing portion) that adsorbs the sheet 3 and an ink receiving portion 25 (receiving portion) that receives ink that protrudes outward from the end portion of the sheet 3 when performing borderless printing. Are provided adjacent to each other. A support rib 30 is provided between the sheet adsorbing unit 23 and the ink receiving unit 25 to support the lower surface of the sheet so that the sheet 3 does not sink by suction. The sheet suction unit 23 is maintained at a negative pressure by a plurality of suction holes 24 to which a negative pressure is supplied. The suction hole 24 communicates with the negative pressure generating unit 4 through a space surrounded by the platen 2 and the housing 1. The sheet 3 is adsorbed through the sheet adsorbing portion 23 maintained at a negative pressure by the suction hole 24. In this embodiment, the negative pressure is supplied to each of the ink receiving portion 25 and the sheet suction portion 23 by a single negative pressure generating portion. However, the present invention is not limited to this, and a plurality of negative pressure generation units may be provided so that the negative pressure is individually supplied to the ink receiving unit 25 and the sheet suction unit 23.

  As is well known, borderless printing is a method of performing printing without providing a margin at the edge of the sheet. In order to ensure that no margins are provided, ink is ejected from the nozzles even in a region that protrudes slightly outside the edge of the sheet 3 during printing. Of course, the protruding ink does not get on the sheet but is received and collected by the ink receiving portion 25.

  FIG. 2B is a top view showing a detailed structure of the ink receiving portion 25, and FIG. 2C is a cross-sectional view taken along the line AA in FIG. A long hole 27 for supplying a negative pressure is provided inside the ink receiving portion 25. Similar to the suction hole 24, the long hole 27 communicates with the negative pressure generating unit 4 through a space surrounded by the platen 2 and the housing 1. The long hole 27 includes a predetermined portion 27a (liquid recovery portion) provided at the center of the ink receiving portion 25, and a slit portion 27b (gas recovery portion) elongated in a slit shape downstream in the transport direction with the predetermined portion 27a as an end portion. ). The predetermined portion 27a and the slit portion 27b communicate with each other and form one hole. The predetermined portion 27a has a liquid recovery function of recovering ink (liquid) by negative pressure. Further, the slit portion 27b has a gas recovery function for sucking in gas containing ink mist by negative pressure in order to reduce dirt on the back side of the sheet. Details of each function will be described later.

  The ink receiving portion 25 includes a receiving surface 25a on which ink protruding from the end portion of the sheet 3 lands and a guiding portion 25b. The ink that has landed on the surface of the receiving surface 25a is guided to the predetermined portion 27a of the long hole 27 by the guide portion 25b. That is, the guide portion 25 b has a function of restricting ink from flowing into the slit portion 27 b of the long hole 27. The receiving surface 25a is inclined downward toward the predetermined portion 27a, and ink flows into the predetermined portion 27a by the action of gravity. The guide portion 25b has an elongated groove shape as shown in FIG. 2C, and a step is formed by the groove. When viewed from above, the groove of the guide portion 25b is inclined with respect to the sheet conveying direction, extends toward the predetermined portion 27a, and is connected at the end. Since the receiving surface 25a is inclined, the guide portion 25b formed obliquely is also inclined downward toward the predetermined portion 27a. Therefore, the ink that has entered the groove of the guide portion 25b flows into the predetermined portion 27a by the action of gravity.

  Here, if the ink discarded in the ink receiving portion 25 is not quickly collected in the long hole 27, the ink gradually accumulates in the ink receiving portion 25. The deposited ink will eventually come into contact with the back side of the sheet and the ink jet head, causing dirt and device failure. Therefore, prompt ink recovery is required.

  With reference to FIG. 3, the operation of collecting the ink discarded in the ink receiving portion 25 will be described. 3A is a top view showing the ink receiving portion 25 during printing, and FIG. 3B is a cross-sectional view taken along the line BB in FIG. 3A.

  The ink 50 discharged from the ink jet head 7 and protruding outside the end of the sheet 3 is landed on the receiving surface 25a of the ink receiving portion 25 without landing on the sheet. The ink ejected from the nozzle row of the inkjet head 7 is landed on the receiving surface 25a as a linear ink 50 as shown in FIG. The ink 50 that has landed flows under the action of gravity downward on the inclined receiving surface 25a. The ink that reaches the predetermined portion 27a of the long hole is sucked into the hole. Since the negative pressure is supplied to the predetermined portion 27a, the ink that has landed at each position of the ink 50 on the receiving surface 25a is directed to the predetermined portion 27a having the negative pressure as indicated by an arrow in FIG. Flow in the direction.

  The size of the hole of the predetermined portion 27a only needs to be large enough for ink to flow. If the hole of the predetermined portion 27a is too large, the negative pressure of the ink receiving portion 25 becomes large, and there is a possibility that ink landing will be disturbed. For example, if the size is about 5 mm × 2 mm, ink can be poured and the possibility of disturbing ink landing is low. The slit width of the slit portion 27b is narrower than the predetermined portion width of 2 mm, for example, in the range of 1 to 1.5 mm.

  The predetermined portion 27a is provided near the middle of the ink 50 in the sheet conveyance direction, and the average distance from the landed ink 50 is the shortest. If the predetermined portion 27a is disposed on the upstream side from the center in the transport direction, it is far from the landing position of the downstream ink 50, and the downstream ink 50 cannot be collected quickly.

  Further, the predetermined portion 27a is preferably arranged at a position hidden behind the sheet 3 when viewed from the inkjet head 7 side. This is because if the predetermined portion 27a is provided outside the end portion of the sheet 3, the negative pressure of the predetermined portion 27a directly affects the ink landing. Therefore, in the example of FIG. 3A, the predetermined portion 27a is provided near the middle of the ink 50 while being hidden behind the sheet 3, so that both the quick collection of the discarded ink and the high-quality image printing can be achieved. ing.

  One of the roles of the guiding portion 25b is to quickly collect the ink 50 on the downstream side in the transport direction, which is far from the predetermined portion 27a. When the ink 50 enters the guiding portion 25b, the recovery of the ink 50 is accelerated by the capillary phenomenon of the narrow groove, so that quick recovery is possible. As will be described later, it is more preferable to provide a similar guiding portion on the upstream side in the transport direction.

  Further, another role of the guiding portion 25b is to prevent ink from flowing into the slit portion 27b and enhance the ink mist collecting effect. Here, the cause of the stain on the back side of the sheet due to the ink mist and the occurrence location will be described.

  FIG. 4A is a cross-sectional view of the ink receiving portion 25 during printing (cross section BB in FIG. 3A). From the ink jet head 7, ink fine particles called ink mist are generated together with the discharged ink and float in the vicinity of the ink receiving portion 25. Most of the ink mist 51 follows the path r1 and is collected in the long hole 27 having a negative pressure. Here, if there is a gap S between the support rib 30 that supports the sheet 3 and the sheet 3, a part of the ink mist 51 passes through the gap and follows the path r <b> 2 to reach the sheet suction unit 23, and the suction hole 24 is collected. At this time, the back surface of the sheet 3 is soiled by the ink mist 51 passing through the gap S. This is the cause of dirt on the back side of the sheet.

  According to the inventor's knowledge, when the gap S reaches 0.2 to 0.3 mm, dirt on the back surface of the sheet is likely to occur. In order to reduce contamination on the back side of the sheet, a method of guiding the ink mist 51 following the path r2 to the path r1 by simply expanding the long hole 27 and increasing the negative pressure can be considered. However, as the negative pressure of the long hole 27 is increased, the negative pressure of the ink receiving portion 25 is increased, and the ink landing accuracy is lowered. Therefore, it is necessary to optimize the position and size of the long hole 27 and perform efficient ink mist collection.

  Next, the location where dirt is generated, that is, the location where the gap S is generated will be described. 4B and 4C are side views of the printing apparatus 100. FIG. The pinch roller 16 is disposed to be inclined by an angle θ toward the platen 2 with respect to the transport roller 11. Therefore, the sheet 3 sandwiched between the transport roller 11 and the pinch roller 16 is pressed against the platen 2. In addition, the sheet 3 is adsorbed by the platen 2. Therefore, in the region U on the upstream side in the conveyance direction, the gap S hardly occurs regardless of the sheet type. On the other hand, in the region L on the downstream side in the transport direction, the generation of the gap S is prevented only by the adsorption of the platen 2. If the sheet is small in rigidity, the gap S is hardly generated even in the region L. On the other hand, when using a roll-shaped sheet like this embodiment, a curl remains in the sheet after unwinding. Therefore, the sheet 3 is curled in the CW direction during printing. Due to this curl, a gap S may occur in the region L as shown in FIG. Even when a cut sheet without curling is used, the gap S may be generated by curling in the CW direction or the CCW direction depending on the surrounding environmental conditions (temperature, humidity). Also, depending on the sheet type, when the ink soaks into the sheet, the sheet expands and wrinkles (cockling) occur. When a part of the sheet printed in the region U reaches the region L, the ink is sufficiently immersed. Therefore, wrinkles are likely to occur in the sheet in the region L. Due to the wrinkles, a gap S is generated in the region L. As described above, when the gap S is generated in the region L on the downstream side in the transport direction, the back surface of the sheet is stained when the ink mist 51 passes through the region L.

  A configuration for collecting the ink mist will be described based on the cause of the stain on the back surface of the sheet and the location where it occurs. FIG. 4D is a top view of the platen 2a during printing. In the vicinity of the region L, a slit portion 27b having a negative pressure is provided. By concentrating the negative pressure in the vicinity of the region L that causes the stain, the ink mist 51 that causes the stain on the back surface of the sheet can be recovered to the maximum with the minimum necessary negative pressure. On the other hand, since the gap S does not occur in the upstream region U, the back surface of the sheet is hardly contaminated. In order not to disturb the ink landing accuracy, the region U is not provided with a slit portion.

  In addition, by providing the guiding portion 25b, the discarded ink 50 is prevented from flowing into the slit portion 27b. Therefore, there is a low possibility that the slit portion 27b is blocked by the ink 50 droplets. Accordingly, the slit width of the slit portion 27b is sufficient to allow the ink mist 51, that is, the air to pass therethrough. Accordingly, it is not necessary to increase the opening area of the slit portion 27b more than necessary, and the negative pressure of the ink receiving portion 25 can be suppressed. When the negative pressure of the ink receiving portion 25 is suppressed, the ink landing accuracy is also stabilized.

  With such a configuration, it is possible to achieve both high-quality image printing and reduction of dirt on the back side of the sheet. As a result, reliable collection of discarded ink, reduction of sheet contamination, and high-quality image printing can be balanced at a high level.

  FIGS. 5A and 5B show a modification of the guide portion. FIG. 5A is a top view of the platen 2a during printing, and FIG. 5B is a cross-sectional view taken along the line CC in FIG.

  The guide portion 25b in the previous example has a step due to the groove shape, but in this modification, a step is formed by the rib 29b raised from the ink receiving surface 29a. Other configurations are the same as those of the embodiments described above. When the ink 50 discarded on the receiving surface 29a flows downward on the inclined receiving surface 29a and reaches the rib 29b, it flows into the predetermined portion 27a along the ridgeline between the receiving surface 29a and the rib 29b. That is, the ink 50 flows along the path r4. At this time, collection of the ink 50 is accelerated by capillary action, and rapid collection becomes possible. The rib 29b has a function of guiding the ink toward the predetermined portion 27a and preventing the ink 50 from flowing into the slit portion 27b.

  As shown in FIG. 5B, when the ink mist 51 floating in the ink receiving portion 29 hits the rib 29b, it is bounced back like a path r3, and a small air vortex is generated in the vicinity of the rib 29b. This vortex serves as a resistance to the flow of the ink mist 51, and the ink mist 51 that gets over the rib 29b and reaches the region L can be reduced. According to this modification, the amount of ink mist 51 that reaches the region L can be reduced, so that it is possible to further reduce stains on the back side of the sheet while maintaining high-quality image printing.

  Although the example in which only one guiding portion is provided on the downstream side of the ink receiving portion 25 has been described above, the guiding portions may be provided at a plurality of locations. FIG. 6A shows an example in which a similar rib 200b is added to the upstream side in addition to the rib 200a on the downstream side in the transport direction. FIG. 6B shows an example in which a groove 201b is added on the upstream side in addition to the groove 201a on the downstream side in the transport direction. The ink 50 that has landed on the upstream side in the transport direction is also collected by being guided by the predetermined portion 27a of the long hole along the step of the rib 200b or the groove 201b, so that it can be collected more quickly. One may be a groove portion and the other may be a combination of ribs. For example, the rib 200a may be provided on the downstream side in the transport direction, and the groove 201b may be provided on the upstream side in the transport direction.

  FIG. 6C shows an example in which a plurality of grooves 202a, 202b, 202c, 202d, and 202e are formed on the ink receiving surface. Each of the plurality of grooves is formed to have a step having a directivity that leads to a predetermined portion 302a that sucks ink.

  FIG. 6D shows an example in which the ink receiving surface itself has a curved shape that guides the ink to a predetermined portion of the long hole without providing a groove on the ink receiving surface. The ink 50 is guided in the direction of the arrow along the curved surface of the ink receiving surface 304 and is sucked into the predetermined portion 303a. Even if the ink 50 heads toward the slit portion 303b, it is bounced back by a curved surface. Therefore, the ink 50 does not flow into the slit portion 303b without providing the groove portion.

  FIG. 7 is a view showing a modification of the long hole. In the example of FIG. 7A, the boundary between the predetermined portion 203 and the receiving surface 204 has an arc shape, and in the example of FIG. 7B, the boundary between the predetermined portion 205 and the receiving surface 206 has a triangular shape. Such a shape makes it easy to collect the ink 50 in one place in a short time. The collected ink 50 becomes a large droplet and flows under its own weight.

  In the example of FIG. 7C, a shielding portion 207 is provided between the predetermined portion 208a and the slit portion 208b, and is divided into two holes. The possibility that the ink 50 that has flowed into the predetermined portion 208a will flow into the slit portion 208b is reduced, and the possibility that the slit portion 208b is blocked by the droplets of the ink 50 is reduced. The liquid recovery function of the predetermined portion 208a and the gas function of the slit portion 208b are clearly separated from each other, and the ink mist can be recovered more reliably. In addition, when producing the platen 2 by resin molding, the precision of the adjacent holes may vary. In that case, the predetermined portion 208a and the slit portion 208b may be connected to form a single long hole.

  FIG. 7D shows an example in which the slit width of the slit portion is narrowed toward the downstream. By narrowing the slit width, the negative pressure is consequently suppressed, and the ink landing accuracy can be further stabilized. The density of the ink mist 51 staying in the air is the largest near the predetermined portion 209a and decreases toward the outer slit portion 209b. The reason why the density on the outside is small is that it is easily mixed with outside air. Accordingly, the ink mist 51 can be efficiently recovered by increasing the negative pressure at a portion having a high density and decreasing the negative pressure at a portion having a low density. Accordingly, the present modification example in which the slit width of the slit portion 209b is narrowed toward the downstream in the transport direction according to the density of the ink mist is effective.

  FIG. 8 shows still another modification of the long hole. 8A is a top view of the platen 2a, and FIG. 8B is a cross-sectional view taken along the line DD of FIG. 8A. It is desirable that the ink mist 51 collected in the slit portion be collected smoothly without winding a vortex. This is because when the vortex is generated, the original recovery function of the ink mist 51 slit portion may be deteriorated. Therefore, a plurality of partition plates 33 are provided as rectifying means for rectifying the gas sucked into the slit portion 210b so that the ink mist 51 collected in the slit portion 210b does not spiral. Since the ink mist 51 is sucked along the partition plate 33, the sucked air is rectified and stabilized. FIG. 8C is a further improvement of FIG. 7D, and the slit width of the slit portion 211b becomes narrower toward the downstream in the transport direction, and a plurality of partition plates 34 are provided here as rectifying means. Rectifying effect.

  FIG. 9 shows a modification of the support rib. As described above, the back of the sheet is stained due to the ink mist 51 passing through the region L. In this modification, the slit width of the downstream rib 250a corresponding to the slit portion 251b in the support rib 250 is increased. Moreover, the shape which makes the slit width | variety of the downstream rib 250a wide toward the downstream may be sufficient. This makes it difficult for the ink mist 51 to enter the gap formed by the downstream rib 250a and the sheet 3. Since the ink mist 51 passing through the region L is reduced, the stain on the back surface of the sheet is also reduced. The rib width of the downstream rib 250a of the support rib 250 is wider than the rib width of the upstream rib 250b. If the distance between the end portion of the sheet 3 and the sheet adsorbing portion 23 (distance V in FIG. 9) is large, the end portion of the sheet 3 is lifted, and the possibility that the inkjet head 7 and the sheet 3 are touched increases. Therefore, the upstream rib 250b maintains the rib width and suppresses the sheet floating, and the downstream rib 250a increases the rib width to suppress the stain on the back surface of the sheet.

2 Platen 7 Inkjet head 25 Ink receiving part 25b Guide part 27 Long hole 27a Predetermined part 27b Slit part

Claims (10)

A printing apparatus comprising a platen that supports a sheet printed by an inkjet head,
The platen is provided with a receiving portion for receiving ink hit on the outside of the sheet by the inkjet head,
The receiving part is formed with a long hole to which negative pressure is supplied and a guide part for guiding the received ink to a predetermined part of the long hole,
The long hole has a slit portion extending downstream in the sheet conveyance direction with the predetermined portion as an end portion, and the guide portion has a shape that restricts the received ink from flowing into the slit portion. A printing apparatus characterized by that.   The guide portion has a receiving surface inclined toward the elongated hole and a step provided on the receiving surface so that ink does not flow into the slit portion, and the step is inclined toward the predetermined portion. The printing apparatus according to claim 1, wherein the printing apparatus is a printer.   The printing apparatus according to claim 2, wherein the receiving surface is provided with a step which is inclined toward the predetermined portion on the upstream side of the predetermined portion with respect to the predetermined direction. .   The guide portion has a receiving surface inclined toward the elongated hole, and the receiving surface has a curved shape that restricts ink received from flowing into the slit portion. The printing apparatus according to claim 1.   5. The printing apparatus according to claim 1, wherein the long hole has a width of the predetermined portion wider than a slit width of the slit portion.   The printing apparatus according to claim 5, wherein the slit width of the slit portion becomes narrower toward the downstream.   The printing apparatus according to claim 1, wherein the slit portion is provided with means for rectifying the sucked air.   8. The shielding part according to claim 1, wherein a shielding part for preventing ink from flowing from the predetermined part into the slit part is formed between the predetermined part and the slit part. 9. The printing apparatus as described in.   The platen is provided with an adsorbing portion that adsorbs a sheet by negative pressure adjacent to the receiving portion, and a support rib that supports the sheet is provided between the adsorbing portion and the receiving portion. The printing apparatus according to claim 1, wherein the printing apparatus is a printer.   The printing apparatus according to claim 9, wherein the support rib is wider on the downstream side than on the upstream side.

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