JP2011063035A - Recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration in recording quality by suppressing sheets floating from a second rib, in a platen configured of a first rib and a second rib positioned on the downstream side of the first rib. <P>SOLUTION: The platen 65, provided opposite to a recording head for printing on a sheet P and supporting the sheet P to specify a gap between the sheet P and the recording head includes the first rib 65a provided on the platen surface 65c opposite to the recording head and extending in a sub-scanning direction and the second rib 65b provided at the downstream side of the first rib 65a and extending in the sub-scanning direction. The protruding height of the first rib 65a from the platen surface 65c is higher than the protruding height of the second rib, thus preventing the sheet P from falling between the first rib 65a and second rib 65b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a platen provided opposite to a recording head for recording on a recording medium and defining a gap between the recording medium and the recording head by supporting the recording medium, and a recording apparatus including the platen. . 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.

  An example of the recording apparatus or the liquid ejecting apparatus is an ink jet printer. The ink jet printer is opposed to an ink jet recording head that discharges ink (liquid) onto printing paper as a recording medium (jetting medium), and a gap (paper gap: hereinafter referred to as “PG”) between the ink jet recording head and the printing paper. A platen that stipulates

  Here, on the surface of the platen that faces the ink jet recording head, a plurality of ribs extending in the sub-scanning direction are provided at predetermined intervals in the main scanning direction. This is to make the distance between the printing surface and the inkjet recording head as uniform as possible by forming a wavy state (so-called “cockling state”) of a constant amplitude on the printing paper that swells by absorbing ink. It is.

  Here, the rib may be provided so as to be divided into an upstream side and a downstream side. As an example, in a printer configured to perform so-called borderless printing, for example, printing is performed without margins on the edge of the printing paper, a slot extending in the main scanning direction is formed so as to divide the rib. In addition, borderless printing is performed by ejecting ink to a portion where the end of the sheet is desired to be a slot and is off the end of the sheet (see, for example, Patent Document 1).

JP-A-2002-86821

  Here, the conveyance roller provided on the upstream side of the platen conveys the printing paper while pressing the printing paper against the platen. This suppresses the lifting of the printing paper from the platen, prevents the occurrence of head rubbing and the change in the gap between the recording head and the printing paper (hereinafter referred to as “PG”), and prevents the deterioration of the recording quality. Because of that.

  However, in the configuration in which the rib extending in the sub-scanning direction is divided in the middle as described above, when the leading end of the sheet reaches the second rib located on the downstream side from the first rib located on the upstream side. When the sheet enters between the first rib and the second rib, the leading end of the sheet tends to rise from the second rib as the leading end of the sheet moves downstream, that is, the leading end of the sheet The state where the two ribs are lifted and headed toward the recording head (upward) occurs. As a result, head rubbing and PG changes occur and the recording quality deteriorates. Further, even when the leading edge of the sheet reaches the downstream discharge roller and is nipped, the sheet falls between the first rib and the second rib, so that the sheet floats on the second rib. In the same manner as described above, head rubbing and PG change are caused and the recording quality is deteriorated.

  Therefore, the present invention has been made in view of such a situation, and the problem is that a platen configured to include a first rib and a second rib located on the downstream side thereof from the second rib of the sheet. It is to prevent the recording quality from being lowered by suppressing the floating.

  In order to solve the above problems, the platen according to the first aspect of the present invention is provided to face a recording head for recording on a recording medium, and supports the recording medium to thereby record the recording medium and the recording medium. A platen that defines a gap with the head, the first rib extending in the sub-scanning direction on the surface facing the recording head, and the second extending in the sub-scanning direction provided downstream of the first rib. A rib is provided, and the protruding height of the first rib toward the recording head is higher than the protruding height of the second rib.

  According to the above aspect, the protruding height of the first rib positioned on the upstream side toward the recording head is higher than the protruding height of the second rib positioned on the downstream side of the first rib. When the recording medium reaches the second rib from the first rib, the degree of depression between the first rib and the second rib can be reduced. As a result, the tendency of the recording medium to rise from the second rib can be reduced or prevented, whereby head rubbing and PG change can be prevented, and deterioration in recording quality can be prevented. Further, even after the leading edge of the recording medium is nipped by the discharge roller on the downstream side, the degree of the recording medium falling between the first rib and the second rib is reduced. A change in PG can be prevented, and a decrease in recording quality can be prevented.

  In addition, the following effects can be obtained. That is, a cockling with a constant amplitude is formed in the main scanning direction by the rib on the recording medium on which ink jet recording has been performed. In general, however, the leading end of the recording medium reaches a downstream discharge roller. Until nip, regular cockling with a constant amplitude is difficult to form, and PG tends to be non-uniform. However, in the present invention, the first rib has a high protruding height, and a conveying roller having a function of pressing the recording medium toward the platen is arranged in the vicinity of the upstream side of the first rib having such a high protruding height. If so, cockling is easily formed even before the leading end of the recording medium reaches the discharge roller downstream of the platen, and as a result, nonuniform PG can be prevented. The cock ring is formed even before the leading end of the recording medium reaches the discharge roller downstream of the platen, so that the floating from the platen can be prevented even before the leading end of the recording medium reaches the discharge roller. .

The platen according to a second aspect of the present invention is the platen according to the first aspect, wherein the first rib is provided on the upstream side of the platen as viewed from the conveyance path of the recording medium so that the recording medium is nipped. And a straight line passing through the nip point of the rotating transport roller and parallel to the surface facing the recording head is provided so as not to protrude toward the recording head.
According to the above aspect, the first rib passes through a nip point of a conveying roller provided upstream of the platen (a nip point when a recording medium is nipped by two rollers) and is a straight line parallel to the surface of the platen. On the other hand, since it is provided so as not to protrude toward the recording head, it is possible to prevent the recording medium from lifting from the first rib.

The platen according to a third aspect of the present invention is characterized in that, in the first or second aspect, the first rib is provided outside an ink ejection region by the recording head.
According to the above aspect, since the first rib is provided outside the ink ejection area of the recording head, the difference in projection amount (height difference) between the first rib and the second rib is PG. The influence exerted can be reduced or eliminated, thereby preventing a decrease in recording quality.

A platen according to a fourth aspect of the present invention includes a recording head for recording on a recording medium, and the platen according to any one of the first to third aspects, provided opposite to the recording head. It is provided with.
According to the above aspect, since the recording apparatus includes the platen according to any one of the first to third aspects, the same effect as any of the first to third aspects described above in the recording apparatus. Can be obtained.

  A liquid ejecting apparatus according to a fifth aspect of the present invention is provided with a liquid ejecting head that ejects liquid onto an ejected medium, and the ejected medium provided to be opposed to the liquid ejecting head and supporting the ejected medium. A liquid ejecting apparatus comprising: a platen that defines a gap with the liquid ejecting head, wherein the platen has a first rib extending in a sub-scanning direction on a surface facing the liquid ejecting head; and the first A second rib provided on the downstream side of the rib and extending in the sub-scanning direction; and a protruding height of the first rib toward the liquid ejecting head is higher than the protruding height of the second rib. It is characterized by being.

1 is an external perspective view of a printer according to the present invention. 1 is an external perspective view of a printer body according to the present invention. 1 is a schematic side sectional view of a printer according to the present invention. FIG. 2 is a plan view of a main part of the printer according to the invention. FIG. 3 is a side sectional view of a main part of the printer according to the invention. FIG. 3 is a side sectional view of a main part of the printer according to the invention. FIG. 3 is a side sectional view of a main part of the printer according to the invention. The perspective view of a face-down paper discharge port. FIG. 3 is a side sectional view of a main part of the printer according to the invention. The side view of a press member. A side view of a platen. The front view of a platen. The top view of a 2nd roller and a 3rd roller.

Hereinafter, one embodiment of the present invention will be described.
1. Inkjet printer schematic configuration
2. Detailed configuration of recording unit
A description will be given in this order with reference to the drawings.
<1. General configuration of inkjet printer>
Hereinafter, a schematic configuration of an ink jet printer (hereinafter referred to as “printer”) 1 as a “recording apparatus” and a “liquid ejecting apparatus” according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. Here, FIG. 1 is an external perspective view of the printer 1, FIG. 2 is an external perspective view in a state in which a cover body constituting the external appearance of the printer 1 is removed, FIG. 3 is a schematic side sectional view of the printer 1, and FIG. FIG. 5 to 7 are partial enlarged views of FIG. 3, and show variations of the paper conveyance (paper discharge) path in the printer 1 (main-part side cross-sectional views). Further, FIG. 8 is a perspective view of the Fd paper discharge port 500.

  In FIG. 1, ink droplets as an example of “liquid” are ejected onto printing paper (mainly cut sheet paper: hereinafter referred to as “paper P”) as an example of “recording medium” and “ejection medium”. The printer 1 that performs recording is configured to be capable of connecting an apparatus main body 1a and an optional paper feeding unit (hereinafter referred to as "OPT unit") 3 below the apparatus main body 1a. The apparatus main body 1a has a paper feed section, a recording section, a paper discharge section, and the like (details will be described later). On the other hand, the OPT unit 3 supplies set sheets P one by one toward the upper apparatus main body 1a. A paper feed unit (not shown) for paper is provided.

  This printer 1 has a paper feed tray 200 in the apparatus main body 1a and a paper feed tray 300 in the OPT unit 3, and a large number of sheets P (500 sheets in this embodiment) are placed in both paper feed trays. It can be set in a stacked state. On the apparatus main body 1a side, a manual paper feed port 202 capable of manually feeding paper P of an arbitrary size is provided above the paper feed tray 200. Further, on the OPT unit 3 side, the paper feed tray 300 is provided so as to be detachable from the OPT unit 3, and the paper P can be set while being detached from the OPT unit 3.

  Next, the printer 1 has a face-down (hereinafter abbreviated as “Fd”) sheet discharge port 500 for discharging the recorded sheet P toward the front side of the apparatus at the upper part of the apparatus main body 1a. On the contrary, it has a face-up (hereinafter abbreviated as “Fu”) paper discharge port 600 for discharging toward the rear side of the apparatus. On the Fd paper discharge port 500 side, a cover 150 is provided that can be opened toward the front side of the apparatus by rotating about a rotation axis provided on the front side of the apparatus.

  FIG. 1 shows a state in which the cover 150 is opened. In the opened state, the cover 150 functions as a paper discharge stacker that stacks the paper P discharged from the Fd paper discharge port 500. In the closed state, the external appearance of the upper part of the apparatus is configured and the function of preventing entry of dust and the like into the apparatus is achieved. Further, on the Fu paper discharge port 600 side, a paper discharge stacker 601 is provided in an inclined posture, and the paper P discharged from the Fu paper discharge port 600 is sequentially stacked on the paper discharge stacker 601 in an inclined posture. The

  Next, FIG. 2 shows a state in which the cover body constituting the external appearance of the printer 1 is removed. In FIG. 2, a plurality of ink cartridges 105 (four in this embodiment) are set in the width direction of the printer 1 (main scanning direction of an ink jet recording head 100 described later) on the upper front side of the apparatus main body 1a. The cartridge mounting frame 110 is provided. In the printer 1 according to this embodiment, a total of four ink cartridges 105 for black, cyan, magenta, and yellow are arranged side by side in the width direction of the printer 1. The ink cartridge 105 is exposed by opening a cartridge cover 151 (see FIG. 1) that constitutes the external appearance of the printer 1. In the state where the cartridge cover 151 is opened, the cartridge cover 151 can be attached by being inserted from the front side of the apparatus toward the rear side, and can be removed by being pulled out to the front side of the apparatus.

  Next, the paper transport path of the printer 1 will be outlined with reference to FIG. The printer 1 conveys the sheet P obliquely from the lower front side of the apparatus toward the upper rear side of the apparatus, performs ink jet recording on the sheet P on the inclined conveyance path, and obliquely upwards (forwards) the recorded sheet P. Side (Fd paper discharge port 500)) or rear side (Fu paper discharge port 600)). In addition, the printer 1 reverses the paper P on which ink-jet recording has been performed on the front surface and transports it to the recording unit with the back surface facing up in order to perform ink-jet recording on both the front and back surfaces of the paper P. It has a reversal path.

More specifically, the paper transport path of the printer 1 includes a paper feed unit 2, a recording unit 11, a face-down (Fd) discharge unit (face-down discharge unit) 5, a face-up (Fu) discharge unit 6, and a sheet. The reversing unit (recording medium reversing means) 4 is generally constituted. Although not shown in FIG. 3, a paper feeding unit that feeds paper to the recording unit 11 is further added by mounting the above-described OPT unit 3 below the paper feeding unit 2. The roller 61 and the roller 62 in FIG. 3 are for feeding the paper P from the OPT unit 3 to the apparatus main body 1a.
Hereinafter, each configuration of the paper transport path will be described. In the following, the upstream side of the paper transport path is simply referred to as “upstream side”, and the downstream side of the paper transport path is simply referred to as “downstream side”.

[Paper Feed Unit 2]
The paper feed unit 2 includes a hopper 203, a manual feed tray 201, a pickup roller 25, a paper feed roller 21, and a reverse roller 23. The hopper 203 supports a plurality of sheets P set on the sheet feeding tray 200 (FIG. 1) in a stacked state, and rotates clockwise around the rotation axis 203a by a hopper driving means (not shown). And is configured to be swingable counterclockwise. The hopper 203 is provided with a movable edge guide 204 (FIG. 2) that is slidable in the paper width direction, and the paper P set in the paper feed cassette 200 (FIG. 1) has a frame 206 (FIG. 2) and the movable edge guide 204. And the side edges are guided by. Similarly, a manual feed tray 201 provided above the hopper 203 is provided with a movable edge guide 201a that can slide in the paper width direction. The paper P fed from the manual paper feed port 202 (FIG. 1) is a frame 206. And the side edge is guided by the movable edge guide 201a.

  The pickup roller 25 has an outer peripheral surface made of a high-friction material (for example, a rubber material), and comes into contact with the uppermost sheet P stacked on the hopper 203 when the hopper 203 swings. Then, by rotating in the contact state, the uppermost sheet P is sent to the sheet feeding roller 21 and the reverse roller 23 on the downstream side.

  As with the pickup roller 25, the paper feed roller 21 and the reverse roller 23 have outer peripheral surfaces made of a high friction material. As shown in FIG. 4, the paper feed roller 21 and the reverse roller 23 are provided at positions shifted to the 0 digit side (left side in FIG. 4) in the main scanning direction. The pickup roller 25 described above is also provided at a position biased toward the 0 digit as shown in FIG. Returning to FIG. 3, the paper feed roller 21 is driven to rotate in the rotation direction (counterclockwise in FIG. 3) for feeding the paper P downstream, and the reverse roller 23 rotates to return the paper P to the upstream side. It is rotationally driven in the direction (counterclockwise in FIG. 3). The uppermost sheet P delivered from the hopper 203 by the pickup roller 25 is nipped between the sheet feeding roller 21 and the reverse roller 23, and the sheet feeding roller 21 rotates to cause the first drive on the downstream side. It is fed to the roller 28.

  Here, the reverse roller 23 is provided so that it can be switched between a state in which it is pressed against the paper feed roller 21 (state shown in FIG. 3) and a state in which it is separated from the paper feed roller 21 by a drive mechanism not shown in FIG. Yes. The reverse roller 23 separates the uppermost sheet P on the hopper 203 to be fed and the next and subsequent sheets P to be fed along with the reverse roller 23 in a state of being pressed against the sheet feeding roller 21. Fulfills the function of That is, if the friction coefficient between the paper feed roller 21 and the paper P is μ1, the friction coefficient between the paper P is μ2, and the friction coefficient between the paper P and the reverse roller 23 is μ3, then μ1> μ3> μ2. The high friction material that forms the outer peripheral surfaces of the paper feed roller 21 and the reverse roller 23 is selected so that the relationship is established.

The reverse roller 23 rotates in a direction to return the paper P to the upstream side, so that the next and subsequent paper P to be double-fed can be surely received at the nip point between the paper feed roller 21 and the reverse roller 23. stop. On the other hand, after the front end of the paper P is nipped between the first drive roller 28 and the first driven roller 29, the reverse roller 23 does not hinder the conveyance operation of the paper P by the first drive roller 28, that is, It is separated from the paper feed roller 21 so as not to apply a transport load (back tension).
In the following, for a roller pair that applies a conveyance force to the paper P, a conveyance load (mainly a force that tries to pull the paper P) applied to the paper P on the upstream side of the roller pair is referred to as “back tension”. Conversely, the conveyance load applied to the paper P on the downstream side (mainly, the force that pushes the paper P back from the downstream side to the upstream side) is referred to as “front tension”.

[Recording unit 11]
The recording unit 11 provided on the downstream side of the sheet feeding unit 2 includes a first driving roller 28 and a first driven roller 29 (hereinafter referred to as a “first roller” as necessary) constituting a “first roller”. An ink jet recording head (hereinafter referred to as “recording head”) 100 as an example of a “liquid ejecting head”, a platen 65, a second drive roller 32 and a second driven member constituting a “second roller”. A roller 33 (hereinafter referred to as “second roller” if necessary), an auxiliary roller 35, a third driving roller 36 and a third driven roller 37 (hereinafter referred to as necessary) constituting a “third roller”. Accordingly, this roller pair is referred to as “third roller”).

  The first drive roller 28 is rotationally driven by a drive motor (not shown), and the first driven roller 29 is in contact with the first drive roller 28 and driven to rotate. In the present embodiment, two first driven rollers 29 are pivotally supported on the downstream side (upper side in FIG. 4) of one first driven roller holder 26 as shown in FIG. 4, and the first driven roller holder 26 is 4 are arranged in parallel in the main scanning direction (left-right direction in FIG. 4). Here, the rotation center of the first driven roller 29 is disposed downstream of the rotation center of the first drive roller 28 in the conveying direction, so that the tangent line at the nip point of both rollers is directed to the platen 65. (See FIG. 9). Accordingly, the sheet P that has passed through the first roller is pressed against the platen 65 and is prevented from being lifted from the platen 65. Further, in one first driven roller holder 26, a pressing member 82 that presses the paper P toward the platen 65 is provided in the vicinity of the downstream side of the first driven roller 29. The pressing member 82 functions to prevent the sheet P from lifting from the platen 65, which will be described in detail later.

  Next, on the downstream side of the first drive roller 28, the recording head 100 is provided above the paper conveyance path, and the platen 65 is provided below the paper conveyance path so as to face the recording head 100. . Here, the sheet conveyance path in the recording unit 11 has an inclination angle as illustrated, and in the present embodiment, the sheet conveyance path is configured to have an inclination angle of about 60 ° with respect to the horizontal plane. . Accordingly, the platen 65 and the recording head 100 are provided in an inclined posture as illustrated. The recording head 100 is provided below the carriage 101, and the carriage 101 is provided so as to pass through a carriage guide shaft 103 extending in the main scanning direction (the front and back direction in FIG. 3), and is guided by the carriage guide shaft 103. Receiving power from a driving means (not shown) reciprocates in the main scanning direction.

In the platen 65, a platen surface (a surface facing the recording head 100 in the platen 65) 65c protrudes toward the recording head 100 and extends in the sub-scanning direction (vertical direction in FIG. 4) as shown in FIG. Ribs 65a and second ribs 65b (hereinafter collectively referred to as “ribs” as appropriate) are formed at predetermined intervals in the main scanning direction, and the sheet P has a distance from the recording head 100 by the ribs. Be regulated. The platen 65 is formed with a long hole 65e extending in the main scanning direction. The long hole 65e is provided to more appropriately detect the size (width dimension) of the paper P. That is, an optical sensor (not shown) that detects a reflection component of light emitted toward the platen 65 is provided on the surface of the carriage 101 that faces the platen 65, and the reflectance between the paper P and the platen 65 is provided. By using the difference, the width dimension of the paper P can be detected. However, when the paper P and the platen 65 are the same color, the width dimension of the paper P cannot be detected appropriately. Therefore, in the present embodiment, the radiated light is radiated toward the long hole 65e, thereby making it possible to detect the width dimension of the paper P more accurately.
Note that the rib is divided into the upstream side and the downstream side by the elongated hole 65e, so that the first rib 65a located near the downstream side of the first drive roller 28 and the downstream side of the first rib 65a are located. The second rib 65b constitutes a rib for supporting the paper P.

  Next, returning to FIG. 3, the carriage 101 does not mount an ink cartridge in the present embodiment. As described above, the carriage 101 is illustrated in FIG. 3 from the ink cartridge 105 mounted on the ink cartridge mounting frame 110. Ink is supplied to the recording head 100 through an ink tube which omits the above. Each color ink cartridge 105 is mounted with an IC chip 107 that holds information about each ink cartridge. The IC chip 107 has a built-in storage device that stores fixed information such as ink color, as well as fluctuation information such as the remaining amount of ink. Each IC chip 107 is connected to a receiving antenna (not shown). On the other hand, a carriage 101 that reciprocates in the main scanning direction has a transmitting antenna (not shown) that transmits a radio signal to the receiving antenna. The antenna substrate 109 provided with () is erected substantially vertically.

  The antenna substrate 109 is opposed to the IC chip 107 of one ink cartridge 105 among a plurality of ink cartridges 105 arranged in the main scanning direction when the carriage 101 moves in the main scanning direction. To do. By communicating with the IC chip 107, various information stored in the IC chip 107 can be transmitted to a control unit of the printer 1 (not shown).

  Next, on the downstream side of the recording head 100, a second roller configured to include a second driving roller 32 that is rotationally driven and a second driven roller 33 that is driven to rotate in contact with the second driving roller 32. The paper P on which recording has been performed by the recording head 100 is conveyed downstream by the rotation of the second roller. In addition, an auxiliary roller 35 is provided on the upstream side of the second roller 33, which further prevents the sheet P from being lifted from the platen 65. This will be described in detail later. The second driven roller 33 and the auxiliary roller 35 are in contact with the recording surface of the paper P on which the ink droplets are ejected. Therefore, the second driven roller 33 and the auxiliary roller 35 are toothed to make point contact with the recording surface to prevent ink transfer and white spots. It is composed of rollers.

  Here, as shown in FIG. 4, the second drive roller 32 and the second driven roller 33 are arranged so that the arrangement positions in the main scanning direction coincide with the rib formation positions. In addition, among the plurality of auxiliary rollers 35, the auxiliary roller indicated by the reference numeral 35 c is positioned so as to be approximately in the middle of two adjacent ribs and is in contact with the recording surface of the paper P. The contact point is provided so as to be located slightly below the top of the rib (that is, overlaps with the rib as viewed from the side of the sheet conveyance path). Therefore, when the paper P swells by absorbing ink droplets, the stretched portion escapes between two adjacent ribs, and as a result, a regular wavy state (cockling) is formed on the paper P. Is done. That is, a cock ring is formed which has a crest at the rib position and a trough at the auxiliary roller 35c, thereby making the distance between the paper P and the recording head 100 extremely uneven, or between the rib and the rib. Thus, the problem that the paper P is lifted and rubbed against the recording head 100 is prevented. In addition, the apparent rigidity in the transport direction is increased by the formation of the cock ring, and even if the front tension is generated, the effect that the paper P does not easily lift (is difficult to bend) in the recording head 100 can be obtained. . The auxiliary rollers 35a, 35b, and 35d as “side end pressing rollers” disposed at the both end positions of the paper P will be described in detail later.

  Next, a third roller having a third drive roller 36 and a third driven roller 37 is provided downstream of the second roller. The third roller serves to assist the sheet conveying force exerted by the upstream second roller to reliably convey the recorded sheet P to the downstream side, and to the sheet P between the second roller and the second roller. By forming the bending posture, the paper P is smoothly bent and reversed (details will be described later).

[Face Down (Fd) Discharge Unit 5]
Next, the Fd discharge unit 5 provided on the downstream side of the recording unit 11 includes a third drive roller 36 and a third driven roller 37, an Fd discharge drive roller 41, and an Fd discharge driven roller 43. The sheet P is discharged with the recording surface facing down by turning the recording surface of the sheet P inward with the recording surface turned inward.
More specifically, on the downstream side of the third roller, the sheet P conveyed from the recording unit 11 by the third roller is switched to either the face-down (Fd) discharge path or the face-up (Fu) discharge path. A Fu switching member 503 is provided. The Fd discharge route is a paper discharge route for discharging the paper P from the Fd paper discharge port 500 (FIG. 1), and the Fu discharge route is a paper discharge route for discharging from the Fu paper discharge port 600 (FIG. 1).

  The Fd / Fu switching member 503 is provided so as to be swingable (clockwise and counterclockwise in FIG. 3) with the swinging shaft 503a as a center when viewed from the side of the paper discharge path. The traveling direction of the paper P sent from the section 11 to the downstream side is switched. The Fd / Fu switching member 503 is provided outside the curve reversal path in the Fd discharge path, and the sheet P is curved and reversed by the curved surface 503b. The curved surface 503b is smoothly formed to reduce the frictional resistance with the paper P and prevent an increase in front tension. Further, the curved surface 503b is formed by providing a plurality of ribs (not shown) at a predetermined interval in the width direction of the paper P (the front and back sides in FIG. 3), that is, uniform. Since this is not a surface, this also reduces the frictional resistance with the paper P.

  Next, FIG. 5 shows a state in which the Fd / Fu switching member 503 switches the traveling direction of the paper P sent from the recording unit 11 to the downstream side to the Fd discharge path. The leading edge of the paper P sent from the recording unit 11 to the downstream side comes into contact with a smooth curved surface 503 b formed on the Fd / Fu switching member 503. The leading edge of the sheet P advances while contacting the curved surface 503b and the guide member 505 provided on the downstream side of the curved surface 503b, and is eventually nipped by the Fd discharge driving roller 41 and the Fd discharge driven roller 43. The Fd discharge drive roller 41 is formed of a rubber roller and is rotationally driven by a drive unit (not shown). The Fd discharge driven roller 43 is formed by a toothed roller and is driven to rotate in contact with the Fd discharge drive roller 41. Then, the Fd discharge driving roller 41 is driven to rotate, whereby the paper P on which recording has been performed is discharged from the Fd paper discharge port 500 (FIG. 1) toward the front of the apparatus (the direction indicated by the arrow “Fd”). .

  As shown in FIG. 8, a stack lever 509 is disposed in the vicinity of the side edge position of the paper P (in this embodiment, the side edge positions of A4 size and B5 size) at the paper discharge port 500. As shown in FIGS. 3 and 5 to 7, the stack lever 509 is attached to the rotation shaft 41 a of the Fd discharge driving roller 41 so as to be swingable about the rotation shaft 41 a, and is discharged from the Fd paper discharge port 500. The sheet P to be pressed is pressed from above. This is because when the sheet P absorbs ink and swells, it tends to curl so as to have a convex shape with the recording surface facing upward. The curling is promoted by the applied load, and as a result, when the paper is discharged from the Fd paper discharge port 500, both side edges of the paper P jump up, and an obstacle occurs when the subsequent paper P is discharged. Because it becomes. Therefore, by providing the stack lever 509 that presses both side edges of the paper P from above, the problem peculiar to a printer having a configuration in which the paper P is curved and reversed after ink jet recording, that is, the curl problem is solved. be able to. Note that the stack lever 509 is preferably configured to adjust the pressing force by using an urging means (for example, a torsion spring or the like) as necessary.

  When the paper P is discharged through the Fd discharge path, the paper P is bent into a substantially U shape with the recording surface inside and discharged. Accordingly, when the paper is discharged while proceeding through the Fd discharge path, the sheets P stacked on the paper discharge stacker 150 (FIG. 1) are stacked in order in the page order, which is convenient for the user. improves.

[Face-up (Fu) discharge unit 6]
Returning to FIG. 3, the Fu discharge unit 6 provided downstream of the recording unit 11 and at the rear part (right side in FIG. 3) of the apparatus main body 1 a includes a Fu discharge drive roller 45, a Fu discharge driven roller 47, A Fu auxiliary roller 49 and an uneven roller 48 (see FIG. 6) are provided. When the paper P is discharged through the Fu discharge path, the Fd / Fu switching member 503 swings clockwise from the state shown in FIG. As a result, as shown in FIG. 6, a paper transport path is formed in which the paper P sent from the recording unit 11 to the downstream side travels straightly upward (upper right direction in FIG. 6). The paper P sent downstream from the recording unit 11 is nipped by the Fu discharge driving roller 45 and the Fu discharge driven roller 47, and the Fu discharge driving roller 45 is driven to rotate, whereby the Fu paper discharge port 600 (see FIG. 1) and discharged toward the rear of the device (direction indicated by arrow “Fu”).

The Fu discharge driven roller 47 is a toothed roller, and is configured to be driven and rotated in contact with the Fu discharge drive roller 45 formed by a rubber roller. Further, the Fu discharge drive roller 45 is provided on the discharge direction side of the paper P (the right side in FIG. 6: the rear side of the printer 1). Further, a Fu auxiliary roller 49 made of a toothed roller is provided in the vicinity of the downstream side of the Fu discharge driven roller 47, and assists the discharge operation of the paper P together with the uneven roller 48.
The driven roller 44 provided on the Fd / Fu switching member 503 is provided so as to be freely rotatable so that the recording surface of the paper P does not come into contact with the Fd / Fu switching member 503 and the recording quality is not deteriorated. This is a toothed roller that makes point contact with the paper P.

  When the sheet P is discharged through the Fu discharge path, the sheet P is not formed in a curved state, and is discharged substantially straight from the recording unit 11 with the recording surface up. Therefore, by using the above Fu discharge path, it is possible to record easily and appropriately discharge even thick paper and stiff paper.

[Paper Inversion Section 4]
Returning to FIG. 3, the sheet reversing unit 4 provided at the rear portion (right side in FIG. 3) of the printer 1 is a roller constituting the Fu discharge unit 6 such as the Fu discharge driving roller 45 and the Fu discharge driven roller 47 described above. And a guide drive roller 51, a movable guide driven roller 52, a guide drive roller 53, a guide driven roller 54, a reverse drive roller 55, a reverse driven roller 57, and a guide roller 59. Yes.

  As shown in FIG. 7, the sheet reversing unit 4 presses the rear end portion of the sheet P that has progressed through the Fu discharge path so as to be substantially along the vertical direction, and the Fu discharge drive roller 45 and the guide drive roller 51. Is rotated in the counterclockwise direction in the drawing, so that the paper P is drawn into the paper reversing unit 4 without being discharged from the Fu paper discharge port 600 (FIG. 1).

  More specifically, in FIG. 7, a Fu / R first switching member 401 that pivotally supports the movable guide driven roller 52 formed of a toothed roller so as to freely rotate is provided on the downstream side of the third roller. A Fu / R second switching member 405 is provided at a position facing the first switching member 401. The Fu / R first switching member 401 is provided so as to be swingable around a rotation center (not shown), and the movable guide driven roller 52 is separated from the guide driving roller 51 (the state shown in FIG. 6), and the guide The state (state shown in FIG. 7) in contact with the drive roller 51 is provided to be changeable by a drive mechanism (not shown). The Fu / R second switching member 405 is provided so as to be swingable about the rotation center of the Fu discharge drive roller 45, and is substantially perpendicular to the inclined posture (state shown in FIG. 6) (shown in FIG. 7). (State) can be changed by a driving mechanism (not shown).

  With the above configuration, after the paper P travels the Fu discharge path as shown in FIG. 6 and the rear end of the paper P passes through the guide member 501, the Fu / R first switching member 401 and the Fu / R first The 2 switching member 405 is switched from the state shown in FIG. 6 to the state shown in FIG. As a result, the rear end portion of the sheet P is nipped between the guide drive roller 51 and the movable guide driven roller 52, and the Fu discharge drive roller 45 that is driven reversely (counterclockwise in the figure) in this state, and the guide drive roller In response to the conveying force 51, the paper P advances in the vertical downward direction with the trailing edge of the paper P as the head.

Note that the paper P traveling through the paper reversing unit 4 has a traveling direction opposite to that at the time of recording on the first recording surface (front surface). That is, the side that was the leading edge at the time of the first recording is the trailing edge side, and the side that was the trailing edge is the leading edge side. ”And the rear end side will be expressed as“ sheet P rear end (R) ”.

Subsequently, referring back to FIG. 3, on the downstream side of the guide drive roller 51, a guide drive roller 53 that is rotationally driven and a guide driven roller 54 that is driven to rotate in contact with the guide drive roller 53 are provided. As a result, the leading end (R) of the paper P is nipped by the pair of rollers and is further conveyed downstream.

On the downstream side of the guide drive roller 53, a large-diameter guide roller 59 is provided, and a curved reversal path having a substantially U shape with the guide roller 59 at the center is formed. A reversal drive roller 55 that is rotationally driven is provided on the side facing the guide roller 59, and the front end of the sheet P (by the reversal drive roller 55 and the reversal driven roller 57 that rotates in contact with the reversal drive roller 55). When the sheet R is nipped, the sheet P further proceeds along the curve reversal path.

  Here, the guide roller 59 has a smooth surface and is configured to be freely rotatable. This is because the surface of the paper P facing the guide roller 59 is a recording surface (front surface) on which ink droplets have already been ejected, and therefore, for example, a rubber roller that is rotationally driven is arranged on such an existing recording surface. This is because the recording quality is lowered by rubbing against the already recorded surface.

Further, the reverse driven roller 57 is provided so as to lightly contact the reverse drive roller 55 by an urging means (not shown). On the other hand, the leading edge (R) of the paper P is eventually nipped between the first driving roller 28 and the first driven roller 29 and conveyed to the recording head 100, but is caused by the first driving roller 28 and the first driven roller 29. The conveyance force of the paper P is stronger than that of other roller pairs. Accordingly, when the leading end (R) of the paper P is nipped between the first drive roller 28 and the first driven roller 29, the reverse driven roller 57 resists the biasing force of the biasing means by pulling the paper P. In some cases, the reverse drive roller 55 may be separated. Then, the shape of the curved reversal path changes, resulting in a problem that a stable transport operation of the paper P cannot be realized. However, since the guide roller 59 is provided so as not to be displaced in the direction orthogonal to the rotation axis direction, the guide roller 59 can stably maintain the curved reversal path while keeping the recorded surface properly protected. It is possible to realize the transporting operation of the paper P.

  The reverse driven roller 57 is not a toothed roller, but is a roller having a smooth surface that is in surface contact with the paper P. This is because the reverse driven roller 57 is provided in a portion where the paper P is curved and reversed, so that the paper P may come into strong contact with the reverse curved roller 57 and the surface of the paper P in contact with the reverse driven roller 57 is This is because the already recorded surface (surface) from which ink droplets have already been discharged is necessary to protect the already recorded surface.

  Further, as shown in FIG. 4, the reverse driven roller 57 is disposed in the vicinity of both side end positions of the paper P (A4 size and B5 size in the present embodiment), and the number of rollers disposed therebetween is minimized. Is preferred. In the present embodiment, the reverse driven rollers 57 indicated by reference numerals 57a and 57d are positioned at both side edges of the A4 size paper P, and the reverse driven rollers 57 indicated by reference numerals 57b and 57d are provided at both side edges of the B5 size paper P. To position. Further, the reverse driven roller denoted by reference numeral 57 c is positioned between the reverse driven rollers 57 disposed on both side ends of the paper P. As a result, even if warping tends to occur at both side edges due to recording on the first surface of the paper P, the both-side edges are nipped by the reverse drive roller 55 and the reverse driven roller 57, so the warp tendency The paper P can be smoothly transported to the downstream side by reducing the transport load at the time of transporting the paper P by the transport drive roller 28 and the transport driven roller 29 on the downstream side, and good recording can be achieved. The result can be obtained.

When the sheet P passes through the curved reversal path formed by the guide roller 59 and the leading end (R) of the sheet P is nipped between the first driving roller 28 and the first driven roller 29, the sheet P is conveyed to the recording head 100, and the sheet P Recording on the back side of P is executed. In this embodiment, the sheet P that has passed through the sheet reversing unit 4 passes through the above-described Fu discharge path (Fu discharge unit 6) and is discharged obliquely upward from the Fu sheet discharge port 600 (FIG. 1).
The above is the outline of the overall configuration of the printer 1.

<2. Detailed configuration of recording unit>
Next, the detailed configuration of the recording unit 11 will be described in detail with reference to FIGS. 9 to 13. Here, FIG. 9 is a side view of the sheet conveyance path from the first roller to the third roller, FIG. 10 is a side view of the pressing member 82, FIG. 11 is a side view of the platen 65, FIG. 12 is a front view of the platen 65, 13 (A) -1 and (B) -1 are plan views of the second roller and the third roller, and (A) -2 and (B) -2 are schematic diagrams for explaining the state of the roller passing trace. FIG. In FIGS. 9 and 11, for convenience of explanation, the inclined conveyance path is shown horizontally, and actually, as shown in FIG. 3, the conveyance path of the sheet P is configured to be inclined obliquely upward. ing.

  When the sheet P is lifted from the platen 65 (hereinafter referred to as “paper lift”) in the recording unit 11, it is rubbed with the recording head 100 or the distance from the recording head 100 (paper gap: hereinafter referred to as “PG”). The recording quality deteriorates due to the change in. Further, when the paper P on which cockling is formed by performing ink jet recording is discharged through the Fd discharge path, that is, curved and reversed, the recording surface may be damaged (details will be described later). . Furthermore, in order to further improve the recording quality, it is desirable to make the PG more uniform. Therefore, the printer 1 according to the present embodiment includes means for preventing paper floating, means for preventing damage to the recording surface, and means for making PG more uniform.

  First, a pressing member 82 is provided as a first means for preventing sheet floating. As shown in detail in FIG. 10, the pressing member 82 has a pressing portion 82a whose surface facing the platen surface 65c is a flat surface in a side view and protrudes to the downstream side, and has a pivot shaft 82b as a center. And can be swung clockwise and counterclockwise.

  More specifically, as shown in FIG. 4, in the plan view of the first driven roller holder 26, the pressing member 82 is formed with the same width dimension as the first driven roller holder 26, and the first rib formed on the platen 65. A notch is provided to avoid 65a. Accordingly, by this, the rotation of the pressing member 82 about the rotation shaft 82b causes the tip pressing portion 82a to enter between the two adjacent first ribs 65a and to approach the platen surface 65c side, or vice versa. As shown by reference numeral 82a ', the platen surface 65c can be separated from the platen surface 65c, and the platen surface 65c is urged toward the platen surface 65c by urging means (not shown).

  Hereinafter, the function and effect produced by the pressing member 82 will be described. After recording on the first surface (front surface) of the paper P, when the paper P is reversed by the paper reversing unit 4 and recording is performed on the second surface (back surface), the paper P is When the ink droplet is absorbed, it may be warped in a bowl shape so as to have a convex shape with the first surface facing up. Then, at the time of recording on the second side, both side edges of the paper P are lifted from the ribs, which may cause head rubbing and PG change at the time of recording on the second side, thereby reducing the recording quality.

  In this way, the pressing member 82a functions to prevent the sheet P from being lifted from the rib by the cooperative action with the first rib 65a. That is, when the paper P is released from the nip state by the first roller and proceeds downstream, the side edge of the paper P is curved (curled) toward the platen surface 65c by the first rib 65a and the pressing portion 82a. As a result, the apparent rigidity of the side edge of the paper P is improved, so that head rubbing and PG change can be prevented, and deterioration of recording quality can be prevented. Further, since this curl extends to the downstream side of the pressing portion 82a, the above-described floating prevention effect can be surely obtained even at a location away from the pressing portion 82a to the downstream side.

  By the way, when the paper P is in contact with the vicinity of the rotation shaft 82b of the pressing member 82 and proceeds downstream, the pressing portion 82a is separated from the platen surface 65c by the frictional force with the paper P. There is a possibility that a rotational moment is applied and the pressing effect is reduced. Therefore, a portion in contact with the paper P in the vicinity of the rotation shaft 82b of the pressing member 82 is configured by a contact roller 83 that can freely rotate, thereby preventing the generation of the rotational moment, thereby directing the paper P toward the platen surface 65c. It is pressing firmly.

  Next, as a second means for preventing sheet floating, the protruding height of the first rib 65a from the platen surface 65c (the protruding height toward the recording head 100) is set to be higher than the protruding height of the second rib 65b. It is expensive. That is, FIG. 11A shows a state in which the protruding heights of the first rib 65a ′ and the second rib 65b are the same, and the sheet P conveyed by the first roller is second to the second rib 65a ′. When it reaches the rib 65b, it falls between the first rib 65a ′ and the second rib 65b, so that it tends to float from the second rib 65b as indicated by the reference symbol P ′. Therefore, this may cause head rubbing and PG change, and may reduce the recording quality. Further, even after the leading edge of the paper P reaches the second roller and is nipped by the second roller, the paper P falls between the first rib 65a ′ and the second rib 65b, so that the paper P is also removed from the second rib 65b. The floating of the occurs.

  Therefore, in the present embodiment, as shown in FIG. 11B, the protrusion height of the first rib 65a is made higher than the protrusion height of the second rib 65b, so that the first rib 65a and the second rib 65b The fall of the paper P in the meantime is reduced or prevented to prevent the leading edge of the paper P from being lifted as indicated by the symbol P ′ in FIG. Further, even after the leading edge of the paper P is nipped by the second roller on the downstream side, the degree of the paper P falling between the first rib 65a and the second rib 65b can be reduced or prevented. The floating from the second rib 65b can be reduced or prevented, and the recording quality can be prevented from deteriorating.

  In addition, the following effects can be obtained. That is, the paper P is formed with regular cockling having a constant amplitude in the main scanning direction by the ribs 65a and 65b, but generally, until the leading edge of the paper P reaches the second roller on the downstream side and is nipped. Is difficult to form a regular cock ring with a constant amplitude, and therefore PG is difficult to be uniform. However, in the present embodiment, the protruding height of the first rib 65a is high, and the first roller that presses the sheet P toward the platen 65 in the vicinity of the upstream side of the first rib 65a having a high protruding height as described above. Since the pressing member 82 (not shown in FIG. 11) is provided, this facilitates the formation of a cock ring even before the leading edge of the paper P reaches the second roller downstream of the platen, and thus PG is not uniform. It is possible to prevent the recording quality from deteriorating.

  In FIG. 11, symbol A indicates an ink discharge area by the recording head 100, and the first rib 65 a is disposed outside the ink discharge area of the recording head 100 as illustrated. Therefore, even if the projecting height of the first rib 65a is higher than the projecting height of the second rib 65b, the PG does not become extremely uneven, and the deterioration of the recording quality can be prevented.

  Subsequently, auxiliary rollers 35 a, 35 b, and 35 d as “side end pressing rollers” are provided as a third means for preventing the sheet from floating. As shown in FIGS. 4 and 9, the auxiliary rollers 35a, 35b, and 35d are arranged between the first roller and the second roller in the sub-scanning direction, more specifically, between the recording head 100 and the second roller. In the main scanning direction, the paper P is disposed at both end positions of the paper P (in this embodiment, A4 size and B5 size paper side end positions) and inside the auxiliary rollers 35a, 35b, and 35d (inside the paper). In the vicinity, a rib 65b is located at a predetermined interval from the auxiliary rollers 35a, 35b, and 35d. Further, the auxiliary rollers 35a, 35b, and 35d are provided so as to overlap with the second rib 65b when viewed from the side of the sheet conveyance path (the overlap amount indicated by symbol a in FIG. 9: 0 mm in this embodiment). Larger than 0.6 mm). In FIG. 4, the broken line indicated by E1 indicates a line through which the side edges of all sizes of paper P pass. Similarly, the broken line indicated by E2 is the B5 size, and the broken line indicated by E3 is the A4 size. A line through which the end of the paper P passes is shown. In the present embodiment, the auxiliary roller 35d is located at the side edge of the paper P of all sizes, and the auxiliary roller 35a is located at the side edge of the A4 size and a slightly different width (for example, letter size). The auxiliary roller 35b is located at the side end of the B5 size and a slightly different width.

  The auxiliary rollers 35a, 35b, and 35d are arranged at the end of the paper P, and thus have the following effects. That is, when the paper P enters the curved reversal path in the Fd discharge path, a load (front tension) is generated by this, and at this time, the central portion in the width direction of the paper P is a curved surface 503b (see FIG. 5) of the Fd / Fu switching member 503. 3) strongly touching, while the both side ends are in a free state, there is a tendency to curl inward (raise from the curved surface 503b) instead of strongly contacting the curved surface 503b as compared to the central portion. .

  As a result, a path difference occurs between the width direction center portion and both side end portions of the printing paper, that is, the path length is shorter at the both end portions than at the center portion in the curved reversal path. 5 and the second roller, and as shown by the symbol F in FIG. 5, the side edges of the paper P tend to be lifted from the platen 65. Therefore, in this case, the recording quality deteriorates due to PG change or head rubbing. This is because the sheet P takes a curved posture in the curved reversal path, and the posture is constrained. Therefore, a curved portion in the transport direction that can absorb the path difference is not formed in the curved reverse path.

  However, in this embodiment, the auxiliary rollers 35a, 35b, and 35d do not simply hold the paper P from above, but curl is formed on both side edges of the paper P by the cooperative action with the ribs 65b, thereby making the appearance in the transport direction appear. The upper rigidity is improved, and the floating from the platen 65 is surely prevented. In addition, since curling is formed on both side edges of the paper P, lifting of both side edges is prevented, so that the above-described lifting prevention effect is spread not only in the vicinity of the auxiliary rollers 35a, 35b, 35d but also on the upstream side or downstream side thereof. Can be made. Accordingly, the above-described problems specific to face-down discharge can be reliably solved.

  In the present embodiment, the auxiliary rollers 35a, 35b, and 35d are arranged on the outermost ribs that support both side edges of the paper P, and the curls formed on both side edges of the paper P are platen. Head to 65. That is, since the curl direction does not face the recording head 100, it is possible to prevent rubbing with the recording head 100 on both sides of the paper P. Further, since the ribs are positioned in the vicinity of the inner sides of the auxiliary rollers 35a, 35b, and 35d, the curl can be reliably formed on both side edges of the paper P.

  When ink jet recording is performed on both sides of the paper P, after the recording is performed on the first surface, the paper P absorbs ink droplets and swells, so that the first surface is raised as described above. There is a tendency to warp in a bowl shape so as to have a convex shape. Then, when the sheet P in such a state is reversed by the sheet reversing unit 4 and conveyed again below the recording head 100 with the second side up, both ends of the sheet P are lifted from the platen 65, and the head rubbing and There is a risk of causing PG change. However, since the above-mentioned auxiliary rollers 35a, 35b, and 35d provide the effect of preventing the sheet from floating, it is possible to surely solve such a problem specific to double-sided recording.

  Incidentally, in the present embodiment, the auxiliary rollers 35a and 35b are configured to include a plurality of (two in the present embodiment) toothed rollers in the rotation axis direction. Therefore, even when the width dimension of the paper P varies or when a paper having a slightly different width dimension is used, the curl can be reliably formed at the paper side end by the cooperative action with the rib 65b.

  Even if the paper P is not provided with a curved reversal path downstream of the second roller, the auxiliary rollers 35a, 35b, 35d and the rib 65b cooperate with each other. Since curls are formed on both side edges, it is possible to prevent the sheet P from being lifted from the platen 65 due to various factors, and to prevent the recording quality from deteriorating.

Subsequently, as a fourth means for preventing the paper from floating and a means for preventing damage to the recording surface, the printer 1 uses the second roller and the third roller to remove the cock ring formed on the paper P. Removal means are provided.
That is, since the apparent rigidity in the conveyance direction of the paper P is increased in the state where the cock ring is formed, such a paper P enters the curved reversal path (curved surface 503b: FIG. 3) in the Fd discharge path. Then, there is a case where a problem occurs in that the crest portion of the cock ring is crushed and a wrinkle is formed on the crushed trace. In addition, when the paper P enters the curved reversal path, if the paper P does not bend smoothly, a load (front tension) is generated, which may cause a decrease in recording quality.

  In addition, the sheet P is nipped by a first roller provided on the upstream side of the platen 65 and a second roller provided on the downstream side, the posture of the sheet P is restricted, and the platen is supported by the first roller as described above. It is pressed against the platen 65 to prevent the platen 65 from lifting up. However, when the trailing edge of the paper P is removed from the first roller, the restraint state is released, and the trailing edge of the paper P is easily lifted from the platen 65.

  Therefore, in the present embodiment, a third roller is provided between the second roller and the Fd discharge path, and a tangent line (indicated by reference numeral T1 in FIG. 9) at the nip point (indicated by reference numeral P2) of the paper P by the second roller. In contrast, the nip point (indicated by reference numeral P3) of the paper P by the third roller is disposed on the curved reversal path side (upper side in FIG. 9) of the Fd discharge path. In FIG. 9, a line indicated by reference numeral T2 indicates a line parallel to the tangent line T1 passing through the nip point P3 in order to indicate the position of the nip point P3 of the paper P by the third roller. Moreover, the code | symbol c has shown the space | interval of the tangent T1 and the tangent T2, and is set to about 2 mm in this embodiment.

  With the above configuration, a curved posture (curved posture when the paper conveyance path is viewed from the side) is formed on the paper P between the second roller and the third roller, so that cockling is removed and the paper P is removed. Since the sheet P enters the curved reversal path in this state, it is possible to prevent the above-described wrinkles from occurring, and the curved reversal can be smoothly performed, thereby increasing the load (front tension). It is possible to prevent deterioration of recording quality. Further, since the bending posture formed on the paper P is a bending posture that imparts a tendency to press the paper P against the platen 65, the paper P can be removed from the platen 65 even after the rear end of the paper P is off the first roller. Lifting can be prevented, and this can also prevent deterioration in recording quality.

  From the viewpoint of removing the cock ring, the nip point P3 of the third roller may be arranged on the opposite side of the curve reversal path (lower side in FIG. 9) with respect to the tangent line T1, unlike the present embodiment. Absent. However, when the curve inversion path is located above the platen 65 as in the present embodiment, in other words, when the curve inversion path is a path that reverses the curve with the recording surface of the paper P inside, the third By arranging the nip point P3 of the roller on the curved reversal path side with respect to the tangent line T1, it is possible to remove the cock ring of the paper P and to impart a tendency to press the paper P against the platen 65, and to prevent the occurrence of wrinkles. The lifting of the paper P from the platen 65 can be prevented.

  Further, when a path for curving the sheet P (including both when the sheet P is reversed and when it is not performed) is provided on the downstream side of the third roller, the formation of wrinkles on the sheet P is prevented as described above. In addition, the floating from the platen 65 can be prevented, but the effect of preventing the floating from the platen 65 can be obtained even when the curved path is not provided on the downstream side of the third roller.

  In this embodiment, by adjusting the positional relationship between the second roller and the third roller, a curved posture is formed on the paper P between the second roller and the face-down discharge means, thereby removing the cock ring. However, any configuration may be used as long as it is a means capable of removing cockling (cockling removing means) or a means capable of forming a curved state (curved forming means).

  By the way, since the second driven roller 35 constituting the second roller and the third driven roller 33 constituting the third roller are both in contact with the recording surface of the paper P, in order to prevent ink transfer and white leakage. And a toothed roller having teeth on the outer periphery. On the other hand, however, a slight dot-like passing trace may remain on the recording surface. In particular, the positions of the second driven roller 35 and the third driven roller 33 in the main scanning direction are as shown in FIG. , The passing traces are formed continuously as shown in the portion surrounded by the broken line in FIG. 13A-2, and the passing traces may be easily noticeable.

  Therefore, in the present embodiment, as shown in FIG. 13B-1, both rollers are arranged so that the positions of the second driven roller 35 and the third driven roller 33 do not coincide with each other in the main scanning direction. Therefore, as shown in FIG. 13B-2, the passing trace formed by the second driven roller 35 and the passing trace formed by the third driven roller 33 are dispersed without being continuous, and the passing trace is conspicuous. It becomes possible to solve the problem that it becomes easy.

Next, means for making the PG more uniform will be described.
When the paper P absorbs ink droplets and swells, a undulation phenomenon with an irregular amplitude in the main scanning direction may cause PG to become non-uniform, resulting in a decrease in recording quality or head rubbing. Therefore, as described above, a plurality of ribs (65a, 65b) extending in the sub-scanning direction are formed on the platen surface 65c at a predetermined interval in the main scanning direction, and a cockling (mountain portion) having a constant amplitude in the main scanning direction is formed. ) When the sheet P falls more than necessary between two adjacent ribs (the valley becomes deeper) as indicated by reference numeral P ′ in FIG. It becomes non-uniform and the recording quality decreases. Ink mist is generated by ejecting ink droplets from the recording head 100. If the ink mist adheres to the platen surface 65c, the back surface of the paper P may be soiled when the valley portion contacts the platen surface 65c. There is. In the present embodiment, the configuration is not configured to perform borderless printing. However, in the configuration in which marginless printing is performed by ejecting ink droplets to a portion off the edge of the paper P, a larger amount of ink is used. Mist is generated, and the problem of contamination is likely to occur.

  In addition, when inkjet recording is performed only on the first surface (front surface) of the paper P, even if the second surface (back surface) is soiled by ink droplets, for example, a thick dedicated paper having a coat layer is used. There may be a case where the influence on the recording quality of the first surface is small, such as when a slight amount of ink adheres to the second surface, but in addition to the first surface by providing the sheet reversing unit 4 as in this embodiment. When recording on the second surface, the contamination of the second surface during recording on the first surface becomes a fatal problem. Similarly, if the first surface is soiled during the second surface recording, the recording quality of the first surface is significantly reduced.

  Therefore, in the present embodiment, as shown in FIGS. 4, 9, and 12, the platen 65 protrudes from the surface facing the recording head 100, that is, the platen surface 65c, between two adjacent ribs 65b and 65b. An auxiliary rib 65d that is lower in height than the rib 65b and extends in the sub-scanning direction is provided. Therefore, in particular, as shown in FIG. 12, between the two adjacent ribs 65b and 65b, the trough formed on the paper P (the portion indicated by the symbol V in FIG. 12) is supported by the auxiliary rib 65d. Accordingly, the degree of depression of the valley portion is reduced and PG is uniformized, so that the recording quality can be prevented from being deteriorated, and the valley portion is not in contact with the platen surface 65c, and is a surface on the opposite side to the recording surface. Can be prevented.

Further, in the present embodiment, a plurality of auxiliary ribs 65d (two in the present embodiment) are provided between two adjacent ribs 65b, 65b, so that the troughs are uniformly supported and cock rings (particularly troughs). Part shape) can be made more uniform, and the deterioration of recording quality can be prevented more reliably.
In this embodiment, the auxiliary rib 65d is provided between the two adjacent ribs 65b and 65b so as to support the valley portion. However, any contact preventing means that can prevent contact with the platen surface 65c. Any configuration may be used. For example, it is possible to provide a plurality of protrusions between two adjacent ribs 65b and 65b, thereby preventing the valley portion from contacting the platen surface 65c.

  Furthermore, any support means for supporting the valleys may be used. For example, as described above, a plurality of protrusions may be provided between two adjacent ribs 65b and 65b to support the valley, or other means other than the surface contact with the valley formed on the paper P. Any material can be used as long as it can contact and support the substrate.

DESCRIPTION OF SYMBOLS 1 Inkjet printer, 1a apparatus main body, 2 paper supply part, 3 option paper supply unit, 4 inversion part, 5 face down (Fd) discharge part, 6 face up (Fu) discharge part, 11 recording part, 28 1st drive roller , 29 1st driven roller, 32 2nd driving roller, 33 2nd driven roller, 35 Auxiliary roller, 36 3rd driving roller, 37 3rd driven roller, 65 platen, 65a 1st rib, 65b 2nd rib, 65c Platen Surface, 65d auxiliary rib, 82 pressing member, 82a pressing portion, 83 contact roller, 100 inkjet recording head, 500 Fd discharge port, 600 Fu discharge port, P printing paper

Claims (5)

A platen provided opposite to a recording head for recording on a recording medium and defining a gap between the recording medium and the recording head by supporting the recording medium,
A surface facing the recording head includes a first rib extending in the sub-scanning direction and a second rib provided on the downstream side of the first rib and extending in the sub-scanning direction, and the recording of the first rib. The protruding height to the head side is made higher than the protruding height of the second rib,
A platen characterized by that. 2. The recording medium according to claim 1, wherein the first rib is provided on the upstream side of the platen and nips the recording medium and passes through a nip point of a conveying roller that rotates while viewing the conveyance path of the recording medium. The straight line parallel to the surface facing the head is provided so as not to protrude toward the recording head.
A platen characterized by that. 3. The first rib according to claim 1, wherein the first rib is provided outside an ink discharge region of the recording head.
A platen characterized by that. A recording head for recording on a recording medium;
The platen according to any one of claims 1 to 3, provided to face the recording head.
A recording apparatus comprising: A liquid ejecting head for ejecting liquid onto the ejected medium;
A liquid ejecting apparatus comprising: a platen provided to face the liquid ejecting head and defining a gap between the ejected medium and the liquid ejecting head by supporting the ejected medium,
The platen includes a first rib extending in the sub-scanning direction and a second rib extending in the sub-scanning direction provided on a downstream side of the first rib on a surface facing the liquid ejecting head. The protruding height of the one rib toward the liquid jet head is higher than the protruding height of the second rib.
A liquid ejecting apparatus.

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