JP2006015533A - Recording device and liquid jet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To unerringly prevent head rubbing by deterring the leading edge of a paper from rising up during the recording of the leading edge of the paper and quickly transferring the paper downstream. <P>SOLUTION: A part of a rib 29 provided in the position facing a recording head 13 and regulating the distance between the recording head 13 and the paper P by supporting the paper P is formed lower than other ribs. The lower rib is formed as a short rib 29S by retreating the upstream side end in the transfer direction of a recorded medium downstream from the upstream side end of the high rib. A driving control section 80 to control a subsidiary scanning driving section 81, and a head driving section 82, a main scanning driving section 83 performs a first main scan by using some upstream side ink nozzles (#136 to 180) from among a plurality of ink nozzles (#1 to #180). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a recording apparatus including a recording head that includes a plurality of dot forming elements arranged in the sub-scanning direction on a head surface. The present invention also relates to a liquid ejecting apparatus.
Here, the liquid ejecting apparatus uses an ink jet recording head, and is not limited to a recording apparatus such as a printer, a copying machine, and a facsimile machine that discharges ink from the recording head to perform recording on a recording medium. And a device that ejects a liquid corresponding to the application from a liquid ejecting head corresponding to the ink jet recording head to an ejected medium corresponding to a recording medium, and adheres the liquid to the ejected medium. .
In addition to the recording head, as a liquid ejecting head, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, and an electrode material (conductive paste) used for forming an electrode such as an organic EL display or a surface emitting display (FED) Examples thereof include an ejection head, a bioorganic matter ejection head used for biochip production, and a sample ejection head as a precision pipette.

As an example of a recording apparatus including a recording head including a plurality of dot forming elements arranged in the sub-scanning direction on a head surface, there is an ink jet printer. Hereinafter, an ink jet printer (hereinafter referred to as “printer”) will be described as an example.
The printer includes an inkjet recording head having a plurality of ink nozzles as dot forming elements arranged at a constant pitch in the sub-scanning direction, a platen that defines a distance between a printing sheet as an example of a recording medium and the inkjet recording head. A transport roller (first roller pair) that is provided upstream of the ink jet recording head and transports the printing paper to a region facing the ink jet recording head; and a discharge roller (second roller) that discharges the printed printing paper Vs.).

Here, when the printing paper swells to the ink jet recording head side by absorbing ink, this causes a head rubbing or a gap (a gap between the printing paper and the ink jet recording head: hereinafter referred to as “PG”), There is a possibility that the recording quality may deteriorate. Accordingly, conventionally, ribs extending in the sub-scanning direction are provided on the surface of the platen facing the ink jet recording head at a predetermined interval in the main scanning direction, and the bulging portion is missed between the ribs, that is, printing paper. In such a configuration, a regular wavy state (cock ring) is formed to prevent head rubbing or the like (see, for example, Patent Document 1).
Further, Patent Document 2 discloses a technology in which two types of ribs having different rib heights are alternately arranged, thereby further improving the regularity of cockling and further improving the recording quality. ing.

JP 2002-52771 A JP 2003-291430 A

  However, since the ribs described in Patent Document 2 are all formed to have the same rib length, there is a large difference in rib height at the position where the guide inclined surface on the upstream side in the conveyance direction of the rib is provided. Not appearing. That is, the front end of the paper swells when ink is ejected and is conveyed while growing a wavy shape.At first, the portion immediately upstream where ink is not ejected is dry and has high rigidity. It is difficult to form regular cock rings. Even if the height is low in this state, if it is supported from the bottom at the same time by the same length, it will be difficult to make regular cockling due to the rigidity, and in some cases the leading edge of the paper will be lifted up, There was a risk of contact.

  Also, depending on the recording method, the printing paper is transported all at once at the start of recording until the leading portion of the recording area faces an ink nozzle located downstream of the plurality of ink nozzles, and a part of the ink located downstream There is a method of performing the first main scanning using a nozzle. In this method, after the first main scanning, the leading area of the recording area is completed by repeating the minute feeding of the printing paper and the main scanning performed by expanding the range of ink nozzles to be used on the upstream side. This is because printing disturbance tends to occur when recording the leading edge of the paper, so that the amount of paper sub-scan feed that can cause printing disturbance is kept to a minimum. It becomes effective. Here, in the case of special paper, the paper has high rigidity, and the problem of head rubbing due to the occurrence of cockling due to ink absorption is unlikely to occur. There is a problem of head rubbing. Therefore, when the above recording method is applied to plain paper as it is, since the sub-scan feed amount of the paper is very small at the time of recording at the leading edge of the paper, the time that the paper stays at a fixed position becomes long, and cockling grows as a result. As a result, the risk of head rubbing increases.

  Therefore, the present invention has been made in view of such problems, and the problem is that the head end is prevented from being lifted at the time of recording the front end of the paper and the head is rubbed quickly by transporting the paper downstream. An object of the present invention is to obtain a recording apparatus capable of reliably preventing the recording apparatus.

  In order to solve the above problems, a recording apparatus according to a first aspect of the present invention includes a recording head including a plurality of dot forming elements arranged in the sub-scanning direction on a head surface, and facing the recording head. And a plurality of ribs extending in the sub-scanning direction at an appropriate interval in the main scanning direction on a surface facing the recording head, and supporting the recording medium by the ribs, thereby recording the recording head and the recording target. A platen that defines a distance from the medium, and a first roller pair that is provided on the upstream side of the recording head and nips and rotates the recording medium to convey the recording medium to a region facing the recording head. A second roller pair that is provided on the downstream side of the recording head and nips and rotates the recording medium to convey the recording medium to the downstream side, and main scanning of the recording head. A main scanning driving unit for printing, a head driving unit for driving the dot forming element during the main scanning and recording on a recording medium, and driving control of the first roller pair, Drive that executes a predetermined recording method by controlling the sub-scan driving unit for performing sub-scan feed of the recording medium, and the respective driving units of the main scanning driving unit, the head driving unit, and the sub-scanning driving unit. A part of the ribs in the platen is formed with a lower rib height than the other ribs, and the lower rib is located upstream in the recording medium conveyance direction. The side edge position is configured as a short rib with a short length by being positioned downstream from the upstream end position of the high rib, and the sub scanning direction of the short rib. The position is within the range of the dot forming element. The drive control unit is configured to perform the first main scanning using a part of the dot forming elements on the upstream side in the plurality of dot forming elements. To do.

  According to the above aspect, since the short rib is provided in the platen, the recording medium is greatly bent downward in the upstream portion of the short rib when ink is ejected and the cock ring begins to grow. Can be removed. Therefore, a regular cock ring is first formed in a large cycle without being affected by the portion where the ink is not ejected and the rigidity is high, that is, the upstream portion of the already ejected ink region. In this state, the short ribs of the recording medium that are stable in a state where the rigidity is greatly lowered and the rigidity is lowered because the short ribs that are formed at a low height are supported from below with a delay in timing. Only the vicinity lifts up reasonably (with little resistance), and a regular cockling of the final cycle is formed. At that time, the possibility that the leading end of the recording medium is lifted and contacts the recording head is also reduced.

  In the recording apparatus including the platen capable of exhibiting such an operation effect, the drive control unit that performs main scanning and sub-scanning uses the first dot forming element on the upstream side to perform the first main scanning. Therefore, the effect of the short rib can be further obtained such that the recording medium can be greatly bent downward in the upstream portion of the short rib.

In addition, since the first main scan is performed using a part of the dot forming elements on the upstream side, after the first main scan, the range of the dot forming elements to be used is greatly expanded to the downstream side. Thus, the main scanning can be performed, and thereby the sub-scan feed amount can be increased. Accordingly, at the time of recording at the leading end of the recording medium, the recording medium can be quickly conveyed to the downstream side without staying at a fixed place, and head rubbing due to cockling growth can be prevented.
The “predetermined recording method” means a dot forming method on a recording medium, such as a known interlace recording method, band recording method, pseudo band recording method, or the like.

  A recording apparatus according to a second aspect of the present invention includes a recording head comprising a plurality of dot forming elements arranged in the sub-scanning direction on the head surface, the recording head provided facing the recording head, and the recording head A platen that defines a distance between the recording head and the recording medium by supporting a recording medium with the ribs on the surface facing the recording medium, with a plurality of ribs extending in the sub-scanning direction at appropriate intervals. A first roller pair that is provided upstream of the recording head and that nips and rotates the recording medium to convey the recording medium to a region facing the recording head; and downstream of the recording head A second roller pair for conveying the recording medium downstream by nipping and rotating the recording medium, and a main scanning drive unit for performing main scanning of the recording head. During the main scanning, the dot forming element is driven to perform recording on the recording medium, and the recording medium is sub-scanned by drivingly controlling the first roller pair. And a drive control unit that executes a predetermined recording method by controlling the drive units of the main scan drive unit, the head drive unit, and the sub scan drive unit. In the platen, a part of the rib is formed to have a lower rib height than the other ribs, and the rib having a lower height has a higher upstream end position in the recording medium conveyance direction. It is configured as a short rib with a short length by retreating downstream from the upstream end position of the rib, and the sub scanning direction position of the short rib is within the range of the dot forming element. It is made to be located in the drive The control unit is configured to perform the first main scanning using a part of the dot forming elements located upstream from the top of the short rib in the plurality of dot forming elements. Features.

  According to the above aspect, since the short rib is provided in the platen, the recording medium is greatly bent downward in the upstream portion of the short rib when ink is ejected and the cock ring begins to grow. Can be removed. Therefore, a regular cock ring is first formed in a large cycle without being affected by the portion where the ink is not ejected and the rigidity is high, that is, the upstream portion of the already ejected ink region. In this state, the short ribs of the recording medium that are stable in a state where the rigidity is greatly lowered and the rigidity is lowered because the short ribs that are formed at a low height are supported from below with a delay in timing. Only the vicinity lifts up reasonably (with little resistance), and a regular cockling of the final cycle is formed. At that time, the possibility that the leading end of the recording medium is lifted and contacts the recording head is also reduced.

  In the recording apparatus including the platen capable of exhibiting such an operation effect, a drive control unit that performs main scanning and sub-scanning is located at a part of the upstream side of the top of the short rib. Since the first main scanning is performed using the dot forming elements, the short ribs exhibit that the recording medium can be greatly bent down at the upstream portion of the short ribs. The effect can be obtained with certainty.

In addition, since the first main scanning is performed using a part of the dot forming elements located on the upstream side of the top of the short rib, the dot formation to be used is performed after the first main scanning. The main scanning can be performed by greatly expanding the element range to the downstream side, and thereby the sub-scan feed amount can be increased. Accordingly, at the time of recording at the leading end of the recording medium, the recording medium can be quickly conveyed to the downstream side without staying at a fixed place, and head rubbing due to cockling growth can be prevented.
The “predetermined recording method” means a dot forming method on a recording medium, such as a known interlace recording method, band recording method, pseudo band recording method, or the like.

In the recording apparatus according to the third aspect of the present invention, in the first or second aspect, an ink discarding recess having a substantially rectangular shape in plan view is provided on the upper surface of the platen. An island portion projecting upward is provided in the discard recess, and the upper surface of the island portion has a long rib having a rib length substantially the same as the length in the transport direction of the island portion, and the length The short rib having a shorter rib length than the short rib is provided.
According to the above aspect, the recording medium is reliably and stably supported by the long ribs whose rib length is set long in the ink discarding concave portion, and the short rib length is short with a delay in timing. Since it is supported by the small ribs, the above-mentioned effects become remarkable in borderless recording.

The recording apparatus according to a fourth aspect of the present invention is the recording apparatus according to any one of the first to third aspects, wherein the rib has a predetermined downward direction upstream in the transport direction for guiding smooth transport of the recording medium. A guide inclined surface that is inclined at an angle is provided, and the position of the guide inclined surface of the short rib is configured to recede to the downstream side in the transport direction from the position of the guide inclined surface of the other ribs. To do.
According to the above-described aspect, the leading portion of the recording material swollen after receiving ink discharge does not yet receive ink discharge, and the subsequent portion that is dry and has rigidity contacts the guide inclined surface of the rib. Thus, it is possible to prevent head rubbing by bringing the tip portion into contact with the recording head.

The recording apparatus according to a fifth aspect of the present invention is the recording apparatus according to any one of the first to fourth aspects, wherein the short ribs and the other ribs are alternately arranged in the main scanning direction. And
According to the above aspect, regular cockling of the recording material can be forcibly and reliably formed, and the recording quality can be improved.

  A liquid ejecting apparatus according to a sixth aspect of the present invention is provided with a liquid ejecting head including a plurality of dot forming elements arranged in the sub-scanning direction on the head surface and facing the liquid ejecting head. A plurality of ribs extending in the sub-scanning direction are provided on the surface facing the liquid ejecting head at an appropriate interval in the main scanning direction, and the ejected medium is supported by the ribs to thereby form the liquid ejecting head and the ejected medium. A platen that defines a distance; and a first roller pair that is provided upstream of the liquid ejecting head and nips and rotates the ejected medium to convey the ejected medium to a region facing the liquid ejecting head. A second roller pair that is provided on the downstream side of the liquid ejecting head and nips and rotates the ejected medium to convey the ejected medium downstream; and the liquid ejecting head. A main scanning drive unit for performing main scanning, a head driving unit for driving the dot forming element to eject liquid onto the ejection target medium during the main scanning, and driving the first roller pair By controlling the sub-scanning drive unit for performing sub-scan feed of the ejection target medium and the respective drive units of the main scan drive unit, the head drive unit, and the sub-scan drive unit, a predetermined liquid is controlled. A drive control unit that executes an ejection method, wherein a part of the ribs in the platen is formed with a rib height lower than the other ribs, The upstream end position in the ejected medium transport direction is configured as a short rib with a short length by being positioned downstream from the upstream end position of the high rib, The position of the short rib in the sub-scanning direction is The drive control unit is configured to perform the first main scanning using a part of the dot forming elements on the upstream side in the plurality of dot forming elements. It is configured.

Hereinafter, an ink jet printer 100 as an example of a recording apparatus and a liquid ejecting apparatus according to the present invention will be described with reference to the drawings.
First, an outline of the overall configuration of the inkjet printer 100 will be described with reference to FIGS. 1 to 8. 1 is a perspective view showing the appearance of an ink jet printer, FIG. 2 is a perspective view showing the inside of the ink jet printer, FIG. 3 is a side sectional view showing an outline of the ink jet printer, and FIG. 4 is a plan view showing the inside of the ink jet printer. . 5 is a partially enlarged view of the lower end portion of the hopper 73. FIG. 6 is a flowchart showing a method for detecting the front end position of the sheet. FIG. 7 is a rear perspective view of the main frame 9 showing the attachment state of the rear guide 23. FIG. 7 is a partially enlarged view of FIG.

  An ink jet printer 100 illustrated in FIG. 1 includes a feeding device 70 including a feeding tray 2 that can support a recording medium P (hereinafter also simply referred to as a sheet P) that is an example of an ejected medium in an inclined posture. The inkjet printer has a configuration in which recording is performed on the paper P fed from the feeding device 70 and is recorded on the discharge stacker 50 located below the front surface. As shown in FIG. 1, the ink jet printer 100 is provided with a scanner unit 5 having an openable / closable lid 15 on the upper surface of the printer body 3. Further, an operation panel 11 is provided on the side of the scanner unit 5 so that an image capturing operation using the scanner unit 5 and an image recording operation using the printer body 3 can be performed simultaneously. Yes. Further, the scanner unit 5 itself can be rotated upward about the rotation shaft 17, and as a result, the upper surface of the printer body 3 is opened as shown in FIGS. 2 and 4. The internal structure of the carriage 10, the platen 28, etc. can be visually confirmed, and maintenance can be performed.

  The sheet conveyance path of the inkjet printer 100 is as shown in FIG. In FIG. 3, the feeding device 70 can swing in a clockwise direction and a counterclockwise direction in FIG. 3 about a swinging shaft (not shown), and supports the paper P in an inclined posture together with the feeding tray 2. A hopper 73 is provided. The leading edge of the paper P stacked in an inclined posture on the hopper 73 is supported by a feeding device frame 71 that constitutes the base of the feeding device 70, and the leading edge of the paper is fed as the hopper 73 swings. The uppermost sheet P is brought into pressure contact with the feeding roller 72 while being in sliding contact with the feeding device frame 71.

  Here, at the lower end of the hopper 73, as shown in FIG. 5, there is formed a stepped portion 73a having a shape protruding toward the contact surface 71a with which the leading end of the paper P contacts in the feeder frame 71. Thus, the distance between the lower end of the hopper 73 and the contact surface 71a can be easily managed. However, if the leading edge of the paper P is curled, the leading edge of the paper P enters between the lower end of the hopper 73 and the contact surface 71a, and as a result, there is a possibility of causing a paper feeding failure. In view of this, in the present embodiment, the sheet width direction dimension A of the stepped portion 73a is made sufficiently large so as to prevent the above-described feeding failure. In FIG. 5, reference numeral 75 indicates a friction material that is held by the uppermost sheet P to be fed so that the subsequent sheet bundle is not fed out from the hopper 73.

  Subsequently, returning to FIG. 3, the feeding roller 72 has an arc portion and a straight portion in a side view and has a substantially D shape, and a rubber material is wound around the outer periphery thereof. Can come into contact with a separation roller 74 provided below the feeding roller 72. The separation roller 74 is rotationally driven in a rotational direction (counterclockwise direction in FIG. 3) so as to return the paper P to the upstream side, and is fed in a counterclockwise direction in FIG. By forming a pressure contact between them, the uppermost sheet P to be fed is separated from the next and subsequent sheets P to be fed along with this.

  The sheet P that has advanced downstream from the pressure contact point between the feeding roller 72 and the separation roller 74 is constituted by the rear guide 23 and is constituted by a conveyance driving roller 19a and a conveyance driven roller 19b. Is guided to a conveying roller 19 corresponding to. The rear guide 23 is provided so as to be swingable about the rotation axis of the transport driving roller 19a, and the upstream end thereof is contacted with the lower surface of the feeding device frame 71 by a coil spring 24. It is provided in an energized state.

  As shown in FIG. 7, the rear guide 23 has a long shape in the width direction (main scanning direction) of the paper P. In the present embodiment, the rear guide 23 is formed of a resin material, and extends in the main scanning direction and stands vertically. It arrange | positions so that the window hole formed in the main frame 9 may be penetrated. As shown in detail in FIG. 8, the main frame 9 is formed with projections 9a and 9a parallel to the longitudinal direction of the rear guide 23, and the coil portion 24a of the coil spring 24 is inserted into the projections 9a and 9a. One end 24 b extending from the coil portion 24 a is in pressure contact with the lower surface of the rear guide 23, and the other end 24 c is in pressure contact with the main frame 9. Here, one end 24b of the coil spring 24 is extended to the vicinity of the lower part of the feeding device frame 71 as shown in FIG. That is, the biasing force of the coil spring 24 is configured to act in the vicinity of the contact point between the rear guide 23 and the feeding device frame 71 in the rear guide 23. Accordingly, even if the biasing force of the coil spring 24 acts on a part of the rear guide 23 that is long in the main scanning direction in the longitudinal direction (in this embodiment, two places as shown in FIG. 7), the rear guide 23 Can be prevented from being bent in the longitudinal direction, and the paper P can be guided downstream in a uniform posture in the width direction.

  Subsequently, returning to FIG. 3, the upper portion of the rear guide 23 is provided with a lever 77 that swings around the swing shaft 77 a by contacting the paper P and a sensor 78 that detects the swing of the lever 77. The paper detection device configured as described above is provided, and the paper detection device detects the passage of the leading edge of the paper P or the trailing edge of the paper P.

Then, the sheet P conveyed to the conveying roller 19 is sent in the sub-scanning direction Y orthogonal to the main scanning direction X by the driving rotation of the conveying driving roller 19a while being sandwiched by the conveying roller 19. The recording head 13 is conveyed to an area (recording position 26) facing the recording head 13.
Among these, a plurality of driven rollers 19b for conveyance are provided in the width direction of the paper P, and are individually supported by a roller holder 18 so as to be driven to rotate. The roller holder 18 always receives a biasing force from a biasing means (not shown), so that the transport driven roller 19b is always kept in a nip state in pressure contact with the transport drive roller 19a.

  The sheet P conveyed while being pinched by the conveying roller 19 is pressed from above by an auxiliary pressing roller and a pressing plate (not shown) located in the vicinity of the conveying driven roller 19b and downstream in the sheet conveying direction A, and lifts up. In a state in which this is prevented, the recording head 13 is guided to the recording position 26 below. The sheet P guided to the recording position 26 is recorded through the reciprocating operation of the carriage 10 in the main scanning direction X and the feeding operation of the sheet P in the sheet conveying direction A.

  A recording head 13, which is an example of a liquid ejecting head that performs recording by ejecting (ejecting) ink, which is an example of liquid, onto the paper P or the like is mounted on the lower surface of the carriage 10. Further, as shown in FIG. 2, ink cartridges C of various colors such as black, cyan, magenta, and yellow are detachably mounted on the upper portion of the carriage 10. In addition, a part of an endless belt 7 wound between pulleys 6 provided in the vicinity of both ends in the main scanning direction X is connected to the carriage 10 and receives a driving force from a motor (not shown) to receive the carriage. 10 is guided by the carriage guide shaft 12 so as to be able to reciprocate in the main scanning direction X. A belt-like flat flexible cable (hereinafter referred to as FFC) 8 is connected to the carriage 10 so as to follow the frame 4 located on the front side thereof. The FFC 8 has a role of transmitting information such as the ink remaining amount of the ink cartridge C mounted in the carriage 10 to a control device (not shown).

  A platen 28 that defines a platen gap PG between the head surface of the recording head 13 and the paper P or the like is provided below the recording head 13 so as to face the recording head 13. Note that the platen gap PG is an extremely important element in executing high-precision recording, and is appropriately adjusted according to a change in the thickness of the paper P or the like. This point will be described later.

  A PW sensor 14 is provided so as to face the platen 28 in the carriage 10. The PW sensor 14 includes a light emitting unit (not shown) that emits light toward the platen 28 and a light receiving unit (not shown) that receives reflected light from the platen 28. By utilizing the difference in reflectance with the paper 28, it is possible to detect the edge position (both side edges, leading edge, and trailing edge) of the paper P, and thereby obtain the paper width or paper length.

  Here, a detection method for precisely detecting the leading end position of the paper P using the PW sensor 14 will be described with reference to FIG. In FIG. 6, when the feeding roller 72 is rotated to start feeding paper (step S101), it is monitored whether or not the leading edge of the paper P has passed the position of the PW sensor 14 (step S102). Is detected (Yes in step S102), it is further monitored whether or not the pressure contact state between the feeding roller 72 and the separation roller 74 is released (step S103). In step S102, whether or not the leading edge of the sheet P has passed the position of the PW sensor 14 is determined by the detection lever 77 and the sensor 78 positioned on the upstream side of the conveying roller 19. Further, after the leading end of the sheet P is nipped by the conveying roller 19, the sheet P is conveyed downstream by the normal rotation of the conveying roller 19.

When the pressure contact state between the feeding roller 72 and the separation roller 74 is released (Yes in step S103), the rotation of the conveying roller 19 is stopped (step S104), and the conveying roller 19 is reversed ( In step S105, the leading end position of the paper P is detected by the PW sensor 14 (step S106).
According to the method for detecting the leading edge of the paper described above, the conveyance roller 19 is reversely rotated, that is, the paper P is returned to the upstream side after the pressure contact state between the feeding roller 72 and the separation roller 74 is released. The sheet P can be smoothly returned to the upstream side without receiving a conveyance load from the 72 and the separation roller 74.

  Further, since the outer peripheral surface of the feed roller 72 and the outer peripheral surface of the separation roller 74 are elastic, the rotation of the feed roller 72 is stopped while the feed roller 72 and the separation roller 74 are in pressure contact with each other. For example, when the feeding roller 72 is driven to rotate in the forward rotation direction, the feeding roller 72 is slightly reversed by the action of the elastic force of the outer peripheral surfaces of both rollers. As a result, the control system may be adversely affected. However, since the conveying roller 19 (that is, the feeding roller 72) is stopped after the pressure contact state between the feeding roller 72 and the separation roller 74 is released as described above, the occurrence of the above-described problem is prevented. be able to. In the present embodiment, the transport roller 19 and the feed roller 72 use the same drive source (drive motor).

  Next, referring back to FIG. 3, downstream of the recording head 13 in the sheet conveyance direction A, the discharge roller corresponding to the “second roller pair” configured by the discharge drive roller 20 a and the discharge driven roller 20 b. 20 is provided. Further, the paper P discharged by the discharge roller 20 is discharged onto a placement surface 51 on a discharge stacker 50 which is an example of an ejected medium receiving portion positioned further downstream.

  The discharge driven roller 20b is a toothed roller having a plurality of teeth on the outer periphery thereof, and is rotatably supported by a roller holder for the discharge driven roller. An auxiliary driven roller 22 is provided upstream of the discharge driven roller 20b, and the paper P is pressed slightly downward by the auxiliary driven roller 22. Further, the transport driven roller 19b is disposed slightly downstream of the transport driving roller 19a, and the discharge driven roller 20b is disposed slightly upstream of the shaft driving position of the discharge driving roller 20a. It is arranged.

  With such a configuration, the sheet P is in a curved state commonly called “back-sliding” that slightly protrudes downward between the transport roller 19 and the discharge roller 20 and faces the recording head 13. The sheet P in the position to be pressed is pressed against the platen 28, so that the sheet P is prevented from being lifted, so that recording is normally performed, and a cock ring described later is actively formed. ing. The auxiliary driven roller 22 is composed of a toothed roller like the discharge driven roller 20b, and is pivotally supported by a roller holder for the auxiliary driven roller.

  Next, a recording medium support device 1 applied to the ink jet printer 100 will be described with reference mainly to FIGS. Here, FIG. 9 is an exploded perspective view showing the recording medium support device, and FIG. 10 is an enlarged perspective view showing a part of the platen. FIG. 11 is a front view showing a cockling state of the recording medium immediately after the leading end of the recording medium reaches the guide inclined surface of the long rib, and FIG. 12 is a view showing both the long rib and the short rib. It is a front view which shows the mode of cockling of the recording medium in the state in which the recording medium is supported.

  As shown in FIGS. 3 and 9, the recording medium support device 1 is connected to the front guide 30 integrally including the platen 28, and is swingably connected to the front guide 30, and is downstream in the sheet conveying direction A. And a front guide support 31 located on the side. The front guide 30 includes a swing shaft 32 at an upstream end in the paper transport direction A, and includes three engagement shafts 33 as an example in an intermittent state at a downstream end in the paper transport direction A. ing.

  On the other hand, the front guide support 31 is provided at three positions corresponding to the engagement shafts 33 at the upstream end in the paper transport direction A so as to engage with the engagement shafts 33 in a swingable manner. ing. A bearing structure 35 that rotatably supports the discharge roller shaft 21 that rotates together with the discharge drive roller 20a described above is provided downstream of the front guide support 31 in the sheet conveyance direction A. A member extending from the downstream end of the front guide support 31 in the paper conveyance direction A further downstream is an activation arm 36 that transmits the movement of an operation lever (not shown) to the front guide support 31.

  Note that such a configuration of the recording medium support device 1 is a configuration for adjusting the platen gap PG. By moving an operating lever (not shown) in a predetermined direction, the activation arm 36 or a unit integrated therewith is provided. For example, the front guide support 31 is rotated counterclockwise in FIG. 3 around the discharge roller shaft 21. When the front guide support 31 is rotated counterclockwise, the front guide 30 that is swingably engaged by the engagement shaft 33 and the engagement finger 34 is centered on the swing shaft 32, for example, in FIG. The platen 28 is rotated clockwise, and the platen 28 provided integrally is moved downward to increase the platen gap PG. On the other hand, when an operation lever (not shown) is rotated in the opposite direction, the front guide support 31 and the front guide 30 are rotated in the opposite direction to act to reduce the platen gap PG.

  A plurality of ribs 29 are provided on the upper surface of the platen 28 provided integrally with the front guide 30 to support the lower surface of the paper P with an appropriate interval in the main scanning direction X. Some of the ribs 29 are short ribs 29S having a rib height H lower than the other ribs 29 and a short rib length L. More specifically, the upper surface of the platen 28 is provided with an ink discarding recess 37 which is an example of a liquid discarding recess having a substantially rectangular shape in plan view. The ink discarding recess 37 has a role of collecting excess ink that has not been used for execution of recording and collecting it in one place. The ink discarding recess 37 absorbs the discarded ink. An unillustrated absorption sponge is provided, and a storage container (not shown) for storing the recovered ink is disposed below an opening (not shown) engraved on the bottom surface of the ink discarding recess 37.

  In the ink discarding concave portion 37, an island portion 38 projecting upward is provided, and a long rib 29L having a rib length L substantially the same as the length of the island portion 38 in the paper transport direction A is provided. And the above-mentioned short rib 29S whose rib length L is shorter than this long rib 29L is provided. In addition, a guide inclined surface 39 that is inclined at a predetermined angle toward the lower side on the upstream side in the paper transport direction A is provided at the end of the long rib 29L and the short rib 29S on the upstream side in the paper transport direction A. .

  The position of the guide inclined surface 39 of the short rib 29S is formed so as to recede to the downstream side in the paper transport direction A from the position of the guide inclined surface 39 of the long rib 29L. The head rubbing at the leading edge of the sheet P due to the lifting action on the inclined surface 39 is prevented. Further, in order to forcibly obtain regular cockling of the paper P, the short ribs 29S and the long ribs 29L are alternately arranged in the main scanning direction X.

  Next, how the cockling of the paper P changes as the paper P is transported will be described with reference to FIGS. In a state immediately after the leading edge of the sheet P conveyed toward the recording position 26 is guided by the guide inclined surface 39 of the long rib 29L and reaches the upper surface of the long rib 29L, the cockling of the sheet P is performed. Is formed as shown in FIG. In this state, since the leading edge of the paper P has not yet reached the guide inclined surface 39 of the short rib 29S, a portion that is greatly bent (slack) under the paper P is positioned below the upper surface of the short rib 29S. It is possible to do. As a result, the difference in rib height H between the long rib 29L and the short rib 29S clearly appears, and regular cockling of the paper P is reliably formed as shown. .

  On the other hand, in the state where the conveyance of the paper P has progressed and the paper P has reached the position where it is supported by both the long rib 29L and the short rib 29S, the ribs of the long rib 29L and the short rib 29S. The difference in height H acts on the sheet P as it is, and regular cockling of the sheet P is formed as shown in FIG. Therefore, such a configuration of the rib 29 allows the paper P to be always in a constant and regular cockling state without being affected by the progress of conveyance, and prevents the occurrence of stains due to ink adhesion due to head rubbing. It is.

  Further, a large number of streak-like small ribs 40 extending in the transport direction are provided on the upper surface of the island portion 38 where the ribs 29 are not provided. The small rib 40 functions as a dispersion guide uneven portion that disperses the ink accumulated in the slight concave portion on the upper surface of the island portion 38 so as to be inconspicuous and guides the ink to the ink discarding concave portion 37 around the island portion 38. is doing.

  The recording medium support device 1 is based on the above-described configuration, but it is of course possible to change or omit the partial configuration without departing from the gist of the present invention. . For example, the difference in rib height H between the short ribs 29S and the long ribs 29L can be increased by making the angles of the inclined guide surfaces 39 of the short ribs 29S and the long ribs 29L different. . Moreover, it is also possible to form the distributed guide uneven portion by providing a large number of streak-like grooves instead of the small ribs 40 formed on the upper surface of the island portion 38.

  Further, each of the bearing portions 42, 45, 46 constituting the engagement shaft 38, the engagement finger 34, and the bearing structure 35 is not limited to three, and four or more can be provided. In this case, for example, when the number of bearing portions is increased to four, the intermediate bearing portion 46 can be added and provided at two locations.

  Next, a recording method of the leading edge of the paper P using the above-described recording medium support device 1 (platen 28) will be described with reference mainly to FIGS. Here, FIG. 13 is a side sectional view showing an outline of the ink jet printer, FIG. 14 is an explanatory diagram for explaining the operation effect of the recording system according to the present invention, and FIG. 13A shows a recording system different from the present invention. As an example, (B) shows a recording method according to the present invention. FIG. 15 is a diagram showing the recording method of FIG. 14A in more detail, and FIG. 16 is a diagram showing the recording method of FIG. 14B in more detail.

  First, in FIG. 13, the recording head 13 includes a plurality of dot forming elements (ink nozzles) arranged at a substantially constant pitch along the sub-scanning direction (paper transport direction). Each ink nozzle is provided with a piezo element (not shown) for ejecting ink. In the figure, the broken line indicated by reference numeral # 1 indicates the position of the ink nozzle located on the most downstream side in the paper conveyance direction (sub-scanning direction), and the broken line indicated by reference numeral # 180 indicates the position of the ink nozzle positioned on the most upstream side. Show. The recording head 13 performs main scanning by the carriage 10 being driven and controlled by the main scanning driving unit 83, and all or part of the ink nozzles # 1 to # 180 by the head driving unit 82 during the main scanning. Is driven, and ink is ejected onto the paper P. Here, the sub-scanning direction position of the short rib 29S described above in the present embodiment, in particular, the sub-scanning direction position of the flat top of the short rib 29S is located within the range of the ink nozzles # 1 to # 180. It has been made.

  In the following description, it is assumed that the nozzle array is composed of ink nozzles # 1 to # 180, and the distance between the nozzles (nozzle pitch) is set to 1/180 inch (thus, the ink in the recording head 13). The nozzle area may be about 1 inch long in the sub-scanning direction). For example, the nozzle array may be composed of the above-described half of the ink nozzles (# 1 to # 90 nozzles).

  The conveyance drive roller 19 constituting the conveyance roller 19 provided on the upstream side of the recording head 13 is driven and controlled by the sub-scanning drive unit 81. Here, as described above, the nip point between the transport driving roller 19a and the transport driven roller 19b is set on the downstream side, so that the sheet P is pressed against the platen 28 by the transport roller 19. Nipped and transported. The discharge drive roller 20a provided on the downstream side of the recording head 13 obtains power from a drive motor (not shown) that is a power source of the transport drive roller 19a. The drive is controlled by the drive unit 81.

  The sub-scanning drive unit 81, the head drive unit 82, and the main scan drive unit 83 are controlled by the drive control unit 80. The drive control unit 80 controls each of the drive units according to reading data from the scanner unit 5, recording data sent from an external computer (not shown), and further based on signals sent from various sensors. Accordingly, the sheet P conveyed by the conveying roller 19 is conveyed in a state in which the leading end position is grasped by the drive control unit 80.

  Next, a recording method at the leading edge of the sheet will be described with reference to FIG. FIG. 14 shows a case where recording is performed at 720 dpi by the pseudo band recording method using 180 ink nozzles arranged at 1/180 inch pitch in the sub-scanning direction (vertical direction in FIG. 14) as described above. . Here, the pseudo band recording method refers to a band formed by a plurality of continuous raster lines, in which the dot formation interval is smaller than the pitch width of ink nozzles (in this embodiment, 1/180 inch). A recording method that is completed by a plurality of main scans. Other recording methods include a band recording method in which the dot formation interval is equal to the pitch width of the ink nozzles, and a band constituted by a plurality of continuous raster lines is completed by one main scan of the recording head 13. In addition, there is an interlaced recording method in which main scanning and sub-scanning are performed so that the dot formation interval is smaller than the pitch width of the ink nozzles and a continuous raster line is always formed by different nozzles.

  First, in order to clarify the characteristics of the recording method of the present invention, an outline of a recording method at the leading end of the paper different from the present invention will be described with reference to FIG. In the recording method shown in FIG. 14A, at the start of recording, the sheet P is transported all at once until the leading portion of the recording area faces the # 1 nozzle located on the downstream side of the plurality of ink nozzles, and then on the downstream side. In this method, the first main scanning is performed using some of the ink nozzles (here, # 1 to # 45 nozzles). In this recording method, after the first main scanning, the leading portion of the recording area is completed by repeating the minute feed of the paper P and the main scanning performed by expanding the range of ink nozzles to be used on the upstream side.

  Specifically, in FIG. 14A showing an example of a recording method different from the present invention, at the time of recording at the leading edge of the paper, the first portion of the recording area is located on the downstream side among the plurality of ink nozzles. The paper P is transported at a stroke until facing each other, and the first main scanning (pass number 1) is performed using some of the downstream ink nozzles including the # 1 nozzle. Until the main scan (pass numbers 2 to 4), the paper P is finely fed, and in the case of performing the fifth and subsequent main scans, a band feed of about 1/4 inch is performed.

  More specifically, in this recording system, as shown in FIG. 15, the first line is formed by the # 1 nozzle. At this time, the leading edge of the paper is, for example, outside the area of the ink nozzle (near the downstream side of the # 1 nozzle) and upstream of the discharge roller 20 (paper P indicated by the phantom line in FIG. 13).

  Then, the first main scan (pass number 1) is performed using some of the downstream ink nozzles (here, # 1 to # 45 nozzles). Here, since recording is performed at 720 dpi by the recording head 13 having a nozzle pitch of 1/180 inch, between the plurality of raster lines formed by the nozzles # 1 to # 45 by the first main scanning, the subsequent 2 to 4 Three raster lines are formed by the second main scan, and one band is thus completed.

  After the first main scan, the sub-scan feed of 1 dot (1/720 inch) is performed, and then the range of ink nozzles to be used is expanded to the upstream side, and a larger number of ink nozzles than the first main scan are performed. (Here, # 1 to # 90) is used to perform the second main scan (pass number 2). Further, after the sub-scan feed of 1 dot (1/720 inch) is performed, the range of ink nozzles to be used is further expanded to the upstream side, and more ink nozzles (here, # 1) than the second main scan. The third main scan is performed using (# 135 nozzles) (pass number 3). After further sub-scan feed of 1 dot (1/720 inch), the range of ink nozzles to be used is further expanded to the upstream side, that is, all ink nozzles (# 1 to # 180 nozzles) are used for 4 The second main scan is performed (pass number 4), and as described above, the raster line formed by the # 1 nozzle in the first main scan and the # 45 nozzle in the fourth main scan are formed at the head portion of the recording area. A band with a distance from the measured raster line, that is, about 1/4 inch wide, is completed. Thereafter, sub-scan feed and main scan of about ¼ inch, which is the bandwidth, are alternately performed.

  Specifically, the sub-scan feed amount performed before the fifth main scan is 177/720 inches as shown in the figure, that is, 177/720 inches, 181/720 inches, 181/720 inches, Four sub-scan feeds of 181/720 inches form one set, and are repeatedly executed thereafter.

  In the above recording method, when the leading edge of the sheet is recorded, the leading edge of the sheet does not reach the discharge roller 20 and the posture tends to become unstable. The sub-scan feed amount is kept to a minimum, and is effective only for high-quality printing using dedicated paper. Here, in the case of special paper, the paper has high rigidity, and the problem of head rubbing due to the occurrence of cockling due to ink absorption is unlikely to occur. There is a problem of head rubbing. Therefore, when the above recording method is applied to plain paper as it is, since the sub-scan feed amount of the paper is very small at the time of recording at the leading edge of the paper, the time that the paper stays at a fixed position becomes long, and cockling grows as a result. As a result, the risk of head rubbing increases. The problem of the above-mentioned printing disturbance is that printing on plain paper is more advantageous for printing disturbance than special paper (deterioration of recording quality is not noticeable) due to bleeding of ink droplets that have landed. ing. Therefore, when using plain paper, there is little need to keep the sub-scan feed amount to a minimum when recording on the leading edge of the paper.

Next, according to the recording method according to the present invention described in detail below, head rubbing as described above can be prevented.
First, the recording method at the leading edge of the paper according to the present invention will be outlined. In FIG. 14B showing an example of the recording method according to the present invention, when recording at the leading edge of the sheet, the head is positioned so that the leading edge of the sheet is located within the area of the ink nozzle, and the upstream ink nozzle (# 180 nozzle) The first main scan (pass number 1) is performed by using a part of the ink nozzles including, and when performing the subsequent main scan, the band feed of about 1/4 inch and the main scan are alternately performed. .

  More specifically, as shown in FIG. 16, cueing is performed so that the front end of the paper is located within the ink nozzle area (paper P indicated by a solid line in FIG. 13), and some upstream ink nozzles, particularly In this embodiment, the first main scan (pass number 1) is performed using a part of the ink nozzles (here, # 136 to # 180 nozzles) located on the upstream side of the short rib 29S. Therefore, unlike the above example, the first line is formed by the # 136 nozzle. In this case as well, 720 dpi recording is performed by the recording head 13 having a nozzle pitch of 1/180 inch. Therefore, between the plurality of raster lines formed by the # 136 to # 180 nozzles by the first main scanning, the latter two are used. Three raster lines are formed by the fourth to fourth main scans, thereby completing one band.

  After the first main scan, after performing sub-scan feed of a band width of +1 dot (181/720 inches), the range of ink nozzles to be used is expanded downstream, and more than the first main scan. A second main scan (pass number 2) is performed using ink nozzles (here, # 91 to # 180 nozzles). Further, after performing sub-scan feed for a band width of +1 dot (181/720 inch), the range of ink nozzles to be used is further expanded to the downstream side, and a larger number of ink nozzles than the second main scan (here, The third main scan (pass number 3) is performed using # 46 to # 180 nozzles). Further, after performing sub-scan feed for a band width of +1 dot (181/720 inch), the range of ink nozzles to be used is further expanded downstream, that is, all ink nozzles (# 1 to # 180 nozzles) are expanded. In this manner, the fourth main scan (pass number 4) is performed, and the raster line formed by # 136 nozzles in the first main scan and the # 45 nozzles in the fourth main scan are thus formed at the head of the recording area. A band having a distance from the raster line formed in (1), that is, a 1/4 inch width, is completed. Thereafter, sub-scan feed and main scan of about ¼ inch, which is the bandwidth, are alternately performed.

  Specifically, the sub-scan feed amount performed before the fifth main scan is 177/720 inches as shown in the figure, that is, 177/720 inches, 181/720 inches, 181/720 inches, Four sub-scan feeds of 181/720 inches form one set, and are repeatedly executed thereafter.

  As described above, according to the recording method of the present invention, the drive control unit 80 causes some ink nozzles on the upstream side, in particular, some ink nozzles on the upstream side of the short ribs 29S in this embodiment. Since the first main scanning is performed, the upstream side portion of the short rib 29S can further obtain the operation effect of the short rib 29S such that the sheet P can be greatly bent downward. be able to. In particular, since the paper P is configured to be pressed against the platen 28 by the transport roller 19, the first ink nozzle is used by using the ink nozzles closer to the transport roller 19, that is, some upstream ink nozzles. By performing the main scanning, the side of the paper P where the pressing force against the platen 28 is strong first absorbs the ink, so that cockling is more easily formed. Then, due to the action and effect of the short ribs 29S, the paper P can be easily bent down greatly at the upstream portion of the short ribs 29S, and head rubbing is prevented.

  In addition, since the first main scan is performed by using some ink nozzles on the upstream side, particularly, some ink nozzles on the upstream side of the short ribs 29S in this embodiment, the first main scan is performed. Thereafter, the range of the ink nozzles to be used can be greatly expanded to the downstream side, and main scanning can be performed, whereby the next sub-scan feed amount can be increased. Accordingly, at the time of recording at the leading edge of the sheet, the sheet can be quickly conveyed to the downstream side without being held in a fixed place, and head rubbing due to cockling growth can be prevented.

  In the above example, the case where 720 dpi recording is performed using a recording head having a dot pitch of 1/180 inch is shown, but the present invention is not limited to this embodiment. In the present embodiment, recording is performed using the pseudo band recording method as described above, but recording may be performed using other recording methods (for example, a known interlace recording method).

FIG. 2 is a perspective view showing the appearance of an inkjet printer. The perspective view which shows the inside of an inkjet printer. 1 is a side sectional view showing an outline of an inkjet printer. The top view which shows the inside of an inkjet printer. The elements on larger scale of the lower end part of a hopper. 6 is a flowchart illustrating a paper leading edge position detection method. The rear perspective view of a main frame which shows the attachment state of a rear guide. The elements on larger scale of FIG. The perspective view which decomposes | disassembles and shows the support apparatus of a recording material. The perspective view which expands and shows a part of platen. The front view which shows the state immediately after the front-end | tip of a paper reaches | attains a long rib. The front view which shows the state in which the paper is supported by both the long rib and the short rib. 1 is a side sectional view showing an outline of an inkjet printer. (A) is an example of a recording system, (B) is a diagram showing a recording system according to the present invention. The figure which shows the detail of the recording system of FIG. The figure which shows the detail of the recording system of FIG.14 (B).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support apparatus of recording medium, 2 Feeding tray, 3 Printer main body, 4 Frame, 5 Scanner unit, 6 Pulley, 7 Endless belt, 8 Flat flexible cable (FFC), 9 Main frame, 10 Carriage, 11 Operation panel , 12 Carriage guide shaft, 13 Recording head, 14 PW sensor, 15 Cover, 17 Rotating shaft, 18 Roller holder (of the driven roller for conveyance), 19 Transport roller, 19a Transport drive roller, 19b Transport driven roller , 20 discharge roller, 20a discharge drive roller, 20b discharge driven roller, 21 discharge roller shaft, 22 auxiliary driven roller, 23 rear guide, 24 coil spring, 26 recording position, 28 platen, 29 rib, 29S short size Rib, 29L long rib, 30 front guide, DESCRIPTION OF SYMBOLS 1 Front guide support, 32 Oscillation shaft, 33 Engagement shaft, 34 Engagement finger, 35 Bearing structure, 36 Starting arm, 37 Ink discarding recessed part, 38 Island part, 39 Guide inclined surface, 40 Small rib (Distributed guide unevenness) Part), 41 (deflection prevention roller shaft), 42 base end side bearing part, 43 recessed part, 44 claw part, 45 moving end side bearing part, 46 intermediate part bearing part, 47 projecting part, 48 locking Saddle, 49 inclined surface, 50 discharge stacker, 51 mounting surface, 70 feeding device, 71 feeding device frame, 72 feeding roller, 73 hopper, 74 separation roller, 77 detection lever, 78 sensor, 80 drive control , 81 Sub-scanning drive unit, 82 Head drive unit, 83 Main scan drive unit, 100 Inkjet printer (recording device), P paper (recording material), PG platen gear Flop, X main scanning direction, Y sub-scanning direction, A sheet conveying direction, C ink cartridge, H rib height, L rib length

Claims (6)

A recording head comprising a plurality of dot forming elements arranged in the sub-scanning direction on the head surface;
By providing a plurality of ribs provided in the main scanning direction at appropriate intervals on the surface facing the recording head and extending in the sub-scanning direction on the surface facing the recording head, the recording medium is supported by the ribs. A platen that defines the distance between the recording head and the recording medium;
A first roller pair provided upstream of the recording head and configured to nip and rotate the recording medium to convey the recording medium to an area facing the recording head;
A second roller pair that is provided on the downstream side of the recording head and nips and rotates the recording medium to convey the recording medium downstream;
A main scanning drive unit for performing main scanning of the recording head;
A head driver for driving the dot forming element during the main scanning to record on a recording medium;
A sub-scan driving unit for performing sub-scan feed of the recording medium by controlling the driving of the first roller pair;
A drive control unit that executes a predetermined recording method by controlling each drive unit of the main scanning drive unit, the head drive unit, and the sub-scanning drive unit,
In the platen, a part of the rib is formed with a rib height lower than other ribs,
The rib having a low height is a short rib having a short length because the upstream end position in the recording medium conveyance direction is positioned downstream of the upstream end position of the high rib. And is configured such that the sub-scanning direction position of the short rib is located within the range of the dot forming element,
The drive control unit is configured to perform the first main scanning using a part of the dot forming elements on the upstream side in the plurality of dot forming elements.
A recording apparatus. A recording head comprising a plurality of dot forming elements arranged in the sub-scanning direction on the head surface;
By providing a plurality of ribs provided in the main scanning direction at appropriate intervals on the surface facing the recording head and extending in the sub-scanning direction on the surface facing the recording head, the recording medium is supported by the ribs. A platen that defines the distance between the recording head and the recording medium;
A first roller pair provided upstream of the recording head and configured to nip and rotate the recording medium to convey the recording medium to an area facing the recording head;
A second roller pair that is provided on the downstream side of the recording head and nips and rotates the recording medium to convey the recording medium downstream;
A main scanning drive unit for performing main scanning of the recording head;
A head driver for driving the dot forming element during the main scanning to record on a recording medium;
A sub-scan driving unit for performing sub-scan feed of the recording medium by controlling the driving of the first roller pair;
A drive control unit that executes a predetermined recording method by controlling each drive unit of the main scanning drive unit, the head drive unit, and the sub-scanning drive unit,
In the platen, a part of the rib is formed with a rib height lower than other ribs,
The rib having a low height is a short rib having a short length because the upstream end position in the recording medium conveyance direction is positioned downstream of the upstream end position of the high rib. And is configured such that the sub-scanning direction position of the short rib is located within the range of the dot forming element,
The drive control unit is configured to perform the first main scanning using a part of the dot forming elements located upstream of the top of the short rib in the plurality of dot forming elements. ,
A recording apparatus. 3. The upper surface of the platen according to claim 1, wherein an ink discarding recess having a substantially rectangular shape in plan view is provided on the upper surface of the platen, and an island projecting upward is provided in the ink discarding recess. The upper surface of the island portion is provided with a long rib having a rib length substantially the same as the length in the transport direction in the island portion, and the short rib having a shorter rib length than the long rib. Yes,
A recording apparatus. 4. The guide inclined surface according to claim 1, wherein the rib is provided with a guide inclined surface that is inclined at a predetermined angle toward the lower side upstream in the transport direction for guiding smooth transport of the recording medium. The position of the guide inclined surface of the small rib is configured to recede to the downstream side in the transport direction from the position of the guide inclined surface in the other ribs.
A recording apparatus. The short ribs and other ribs according to any one of claims 1 to 4 are alternately arranged in the main scanning direction.
A recording apparatus. A liquid ejecting head comprising a plurality of dot forming elements arranged in the sub-scanning direction on the head surface;
Provided with a plurality of ribs provided in the main scanning direction at appropriate intervals on the surface facing the liquid ejecting head and extending in the sub scanning direction on the surface facing the liquid ejecting head, and supporting the ejected medium by the ribs. A platen that defines a distance between the liquid ejecting head and the ejected medium;
A first roller pair provided on the upstream side of the liquid ejecting head and configured to nip and rotate the ejected medium to convey the ejected medium to a region facing the liquid ejecting head;
A second roller pair provided on the downstream side of the liquid ejecting head and configured to nip and rotate the ejected medium to convey the ejected medium downstream;
A main scanning drive unit for performing main scanning of the liquid jet head;
A head driving section for driving the dot forming element during the main scanning to eject liquid onto the ejection target medium;
A sub-scan driving unit for performing sub-scan feed of the ejection target medium by controlling the driving of the first roller pair;
A liquid ejecting apparatus comprising: a drive control unit that executes a predetermined liquid ejecting method by controlling each of the main scanning driving unit, the head driving unit, and the sub-scanning driving unit;
In the platen, a part of the rib is formed with a rib height lower than other ribs,
The rib having a low height is a short rib having a short length because the upstream end position in the ejected medium transport direction is positioned backward from the upstream end position of the high rib. And is configured so that the position of the short rib in the sub-scanning direction is within the range of the dot forming element,
The drive control unit is configured to perform the first main scanning using a part of the dot forming elements on the upstream side in the plurality of dot forming elements.
A liquid ejecting apparatus.

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