JP2003291430A - Platen and inkjet recording apparatus comprising the platen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lift-up of the printing paper from the platen surface at the time of printing on the top end of a printing paper even in the case the distance between a conveyance roller and a paper discharging roller is long, and thereby prevent deterioration of the printing quality. <P>SOLUTION: The platen 27 for supporting a printing paper from below between a conveyance driving roller 17a and a paper discharging driving roller 29a has ribs 28a, 28b elongating in the sub scanning direction on the platen surface 27a at substantially equal intervals in the main scanning direction. In the case ink droplets are ejected onto the top end of the printing paper elongating from the conveyance driving roller 17a to the paper discharging driving roller 29a, the printing paper tends to warp upward. However, since the height of the ribs 28b between the two ribs 28a is made lower, the printing paper with the ejected ink droplets falls into the ribs 28b so as to form cockling and prevent upward warpage. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided so as to face an ink jet recording head, and a plurality of ribs extending in the sub-scanning direction are arranged at predetermined intervals in the main scanning direction on the surface facing the ink jet recording head. Further, the present invention relates to a platen that supports a recording material from below by the rib. The present invention also relates to an inkjet recording device equipped with the platen.

[0002]

2. Description of the Related Art An ink jet recording apparatus has an ink jet recording head (hereinafter, referred to as a recording material) having a plurality of nozzle rows for ejecting ink toward a printing paper, which is opposed to a printing surface of a printing paper as one of recording materials. “Recording head”) and a platen that defines the distance between the recording head and the printing surface by supporting the printing paper from below.
Generally, a plurality of ribs extending in the sub-scanning direction are arranged at predetermined intervals in the main scanning direction on the surface of the platen facing the recording head of the inkjet recording apparatus (hereinafter referred to as “platen surface”). During printing, ink drops are ejected from the recording head while the printing paper is supported from below by the ribs.

Here, when the printing paper is lifted from the platen surface, the distance between the printing surface and the recording head cannot be kept constant, and in some cases, head rubbing may occur. Therefore, in order to prevent this, the recording head It is generally used to press the printing paper against the platen surface by a pair of rollers provided on the upstream side and the downstream side.

That is, a transport roller for transporting the print paper is provided on the upstream side of the recording head, and a paper discharge roller for discharging the print paper is provided on the downstream side of the print head. The transport roller and the paper discharge roller are each composed of a drive roller that is rotationally driven and a driven roller that is driven to rotate in contact with the drive roller. Therefore, if the nip point between the driving roller and the driven roller is biased to the recording head side, the printing paper forms a curved state in which the printing paper is convex downward between the conveyance roller and the paper discharge roller. As a result, the printing paper is pressed against the platen surface, and thus the distance from the recording head is kept constant.

[0005]

By the way, in recent years, there has been a marked tendency to increase the number of nozzle holes for ejecting ink droplets to be formed in a recording head in order to enable extremely high-speed printing. When the number of nozzle holes is increased in this way, the size of the recording head (size in the paper feed direction) becomes longer, and as a result, the distance between the transport roller and the paper discharge roller also becomes longer.

However, when the distance between the transport roller and the paper discharge roller becomes long, there arises a problem that the above-mentioned effect of pressing the printing paper against the platen surface is lost. That is, no particular problem occurs after the leading edge of the printing paper is nipped by the paper discharge roller. However, before the leading edge of the printing paper is nipped by the discharge roller, the printing paper is pressed against the platen surface on the side close to the conveying roller, but when ink droplets are ejected onto the printing surface by the recording head, the printing paper is Is extended by the permeation and penetration of ink drops, which results in
There is a possibility that the front end side not nipped by the paper discharge roller may warp upward and the distance between the printing surface and the recording head may become uneven.

Therefore, the present invention has been made in view of such a situation, and its problem is that the platen surface of the printing paper is printed at the time of printing the leading edge of the printing paper even when the distance between the conveying roller and the paper discharging roller becomes long. It is to prevent the print quality from lowering and thus prevent the print quality from deteriorating.

[0008]

In order to solve the above-mentioned problems, a platen according to claim 1 of the present invention is an ink jet recording head for recording by ejecting ink droplets onto a recording material, and an ink jet recording head of the ink jet recording head. A conveying roller which is provided on the upstream side and conveys the recording material to the inkjet recording head; and a discharge roller which is provided on the downstream side of the inkjet recording head and discharges the recorded recording material. In a recording apparatus having the same, a plurality of ribs, which are provided so as to face the inkjet recording head and extend in the sub-scanning direction, are provided at predetermined intervals in the main scanning direction on the surface facing the inkjet recording head. A platen for supporting a recording material from below, wherein at least a part of the plurality of ribs includes a first rib and the first rib. Second ribs having a height lower than that of the first rib are alternately arranged, and the first rib and the second rib are provided while the front end of the recording material reaches from the transport roller to the paper discharge roller. It is characterized in that a wavy state is formed at the leading end portion of the recording material on which the ink droplets have been ejected.

According to the first aspect of the present invention, even if the distance between the transport roller and the paper discharge roller becomes long, the leading end of the recording material does not float up from the platen, thereby preventing deterioration of recording quality. it can. That is, a plurality of ribs extending in the sub-scanning direction are provided at predetermined intervals in the main scanning direction on the surface (hereinafter, referred to as the “platen surface”) of the platen facing the ink jet recording head (hereinafter referred to as “recording head”). It is arranged.

Here, the rib cooperates with the paper discharge roller,
It functions to force the cockling phenomenon on the recording material. That is, when ink droplets are ejected from the recording head onto the recording material, the recording material absorbs the ink droplets and swells, causing a phenomenon of waviness in the main scanning direction (cockling phenomenon). When such a cockling phenomenon occurs on a flat surface, for example, the irregular waviness causes a large variation in the distance between the recording surface and the recording head, which deteriorates the recording quality and, in some cases, the recording surface. It may rub against the recording head and stain the recording surface. Therefore, in order to solve this, generally in an ink jet recording apparatus, ribs extending in the sub-scanning direction are arranged on the platen surface at a predetermined interval in the main scanning direction, and further, between the two adjacent ribs of the recording material. By nipping the portion corresponding to the position with the paper discharge roller or pushing it down with another roller, the top of the cock ring is formed by the rib, and the bottom of the cock ring is formed by the paper discharge roller or the like. As a result, a regular cockling state with a constant period is forcibly formed on the recording material. Thus, the distance between the recording surface and the recording head does not vary greatly, and the recording surface is not rubbed against the recording head.

Here, in order to form a regular cockling state of a constant cycle, it is necessary to arrange the ribs at relatively small intervals. However, when the ribs are arranged at a small interval in this way, the cockling state is formed by the cooperation of the rib and the sheet discharge roller, and therefore, in the state where the recording material is not nipped by the sheet discharge roller. Since the distance between the ribs is small, the recording material ejected with the ink droplets cannot fall downward by its own weight, and as a result, a cockling state is not formed on the recording material. Then, even if the recording material is configured to be pressed onto the platen, the distance between the transport roller and the paper discharge roller becomes long, and as a result, the pressing effect does not reach the vicinity of the paper discharge roller, and ink drops are discharged. The ejected recording material warps upwards,
In some cases, the distance between the recording surface and the recording head becomes non-uniform and the recording quality is degraded.

Therefore, in the platen according to the first aspect of the present invention, at least a part of the plurality of ribs is alternately arranged with the first rib and the second rib having a height lower than that of the first rib. did. Therefore, the recording material that has absorbed the ink drops falls on the second rib having a low height, whereby the recording material has a space between the two first ribs and the two first ribs. A corrugated state (cockling) is formed by the second rib having a low height and disposed at. In other words, it is possible to form the cockling at the leading edge of the recording material while narrowing the rib arrangement interval to form the regular cockling, which increases the distance between the transport roller and the paper discharge roller. Even if it happens, the tip of the recording material does not warp upward, and it is possible to prevent the deterioration of recording quality.

The platen according to claim 2 of the present application is the platen according to claim 1.
In the above, the ribs are arranged at equal intervals in the main scanning direction. According to the invention of claim 2 of the present application, since the ribs are arranged at equal intervals in the main scanning direction, the first ribs and the second ribs are alternately arranged in such a configuration. By doing so, a regular cockling is formed, and thus the distance between the recording surface and the recording head can be made more uniform.

The platen according to claim 3 of the present application is a platen according to claim 1.
Alternatively, in item 2, the distance between the first rib and the second rib is 30 to 70 mm. According to the invention of claim 3 of the present application, the distance between the first rib and the second rib is 30 to 70 mm. Therefore, the recording material is fed by the transport roller and the paper discharge roller. A regular cockling can be formed in the state where the recording material is nipped with the recording material, and when the recording material has not reached the discharge roller, the tip of the recording material that has absorbed the ink droplets is surely Fall into the second rib,
Therefore, even in this case, the cock ring can be reliably formed.

The platen according to claim 4 of the present application is the platen according to claim 1.
3 in any one of the items 1 to 3, the transport roller is configured by a transport drive roller that is rotationally driven and includes a shaft body that is long in the main scanning direction;
A plurality of paper discharge rollers are provided in the main scanning direction, and a position in the main scanning direction is aligned with the conveyance driven roller. And a sheet discharge driven roller that is driven to rotate and is driven to rotate in contact with the sheet discharge drive roller. The rib includes the transport driven roller and the driven roller in the main scanning direction. It is characterized in that it is arranged so as to coincide with the position of the discharge roller. According to the invention of claim 4 of the present application, the positions of the transport roller, the paper discharge roller, and the ribs located between these two rollers in the main scanning direction coincide with each other in the paper feeding direction, so that the main scanning is surely performed. It is possible to form a cock ring having a constant cycle in the scanning direction.

The platen according to claim 5 of the present application is an inkjet recording head for performing recording by ejecting ink droplets onto a recording material, and an inkjet recording head provided upstream of the inkjet recording head for recording the recording material. In a recording apparatus having a conveyance roller for conveying to the ink jet recording head and a discharge roller for discharging the recording material on which recording has been performed, which is provided on the downstream side of the ink jet recording head, the recording apparatus is provided so as to face the ink jet recording head. A platen having a plurality of ribs extending in the sub-scanning direction arranged at predetermined intervals in the main scanning direction on a surface facing the ink jet recording head, the platen supporting the recording material from below by the ribs. Form a wavy state in the main scanning direction on the recording material while the leading edge of the material reaches from the transport roller to the paper discharge roller. Characterized in that it has a cockling forming means.

According to the fifth aspect of the present invention, the platen is a cock which forms a wavy state in the main scanning direction on the recording material while the leading end of the recording material extends from the conveying roller to the paper discharging roller. Since the ring forming means is provided, the cockling is formed on the recording material to prevent the recording material from rising from the platen even when the leading end of the recording material has not reached the discharge roller. Therefore, it is possible to prevent deterioration of recording quality. The "cockling forming means" is a means for forming a corrugated state on the recording material in a state where the leading end of the recording material has not reached the paper discharge roller, and for example, a plurality of them are arranged as described above. At least some of the ribs are first
And the second ribs, which are lower in height than the first ribs, are alternately arranged, the recording material absorbs ink droplets and falls into the second ribs, and the cock Since the ring is formed, the first rib and the second rib form a cock ring forming means. Also, between the ribs,
If suction means for sucking the recording material (for example, air suction holes) is provided, the recording material falls between the ribs and a cock ring is formed, so that the rib and the suction means are formed. Constitutes a cockling forming means.

An ink jet recording apparatus according to claim 6 of the present application is an ink jet recording apparatus for recording on a recording material, and is equipped with the platen according to any one of claims 1 to 5. To do. According to the invention of claim 6 of the present application, the recording apparatus is any one of claims 1 to 5.
Since the platen described in the above item is provided, it is possible to obtain the same effect as the invention described in any one of the first to fifth aspects of the present invention in the recording apparatus.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a schematic side sectional view of the printer 100, FIG. 2 is a plan view of a main constituent element (platen 27) of the recording unit, FIG. 3 is a front view thereof, and FIG.
(A)-(c) is a front view of the platen 27 showing the state of the paper P supported on the platen 27.

First, the paper transport path of the printer 100 will be described with reference to FIG. 1 and also FIG.
In the following, the right side of FIG. 1 (the rear side of the printer 100)
Will be referred to as “upstream side” (upstream side of the sheet conveyance path), and the left side of FIG. 1 (front side of the printer 100) will be referred to as “downstream side” (downstream side of the sheet conveyance path). Printer 100
Has a sheet feeding device 1 at the most upstream side. Paper feeder 1
Is provided in an inclined posture, and is provided with a hopper 11 made of a plate-like body having a swing fulcrum (not shown) in the upper part, and a plurality of sheets P are stacked and held on the hopper 11 in an inclined posture. A paper feed roller 3 which is rotationally driven so as to face the lower end of the hopper 11 and has a substantially D-shape in a side view is provided. The paper feed roller 3 swings in a direction in which the hopper 11 is pressed against the paper feed roller 3. By doing so, the topmost one of the set sheets P comes into pressure contact with the sheet feed roller 3. Then, the paper feed roller 3 is rotationally driven in the pressed state, so that the paper P is fed one by one to the downstream side.

A sheet guide 15 made of a plate-like member is provided substantially horizontally downstream of the sheet feeding device 1, and the leading end of the sheet P fed by the sheet feed roller 3 obliquely contacts the sheet guide 15.
It is smoothly guided to the downstream side. A transport roller 17 including a transport drive roller 17a that is rotationally driven and a transport driven roller 17b that is in pressure contact with the transport drive roller 17a is provided downstream of the paper guide 15, and the sheet P is the transport drive roller 17a. It is nipped with the transport driven roller 17b,
It is transported to the downstream side at a constant pitch.

The transport driven roller 17b is axially supported on the downstream side of the transport driven roller holder 21, and the transport driven roller holder 21 rotates about the rotation shaft 21a in the clockwise and counterclockwise directions in FIG. The transport driven roller 17b is rotatably biased in a direction (counterclockwise direction in FIG. 1) in which the transport driven roller 17b is constantly in pressure contact with the transport drive roller 17a by a torsion coil spring (not shown).

Here, as shown in FIG. 2, the transport driving roller 17a is composed of a shaft body which is long in the main scanning direction (left and right direction in FIG. 2), and the transport driven roller 17b and the transport driven roller holder 21.
And are arranged in the axial direction of the transport drive roller 17a.

Next, returning to FIG. 1, a sensor main body for detecting passage of the paper P is provided in the vicinity of the conveyance driven roller holder 21 located on the most zero digit side (the front side of the plane of FIG. 1: the right side of FIG. 2). A paper detector 19 including 19b and a detection lever 19a is provided. The detection lever 19a has a substantially V shape in a side view, and is provided so as to be rotatable in the clockwise and counterclockwise directions in FIG. 1 about a rotation shaft 19c near the center thereof. The sensor body 1 located above the detection lever 19a
9b includes a light emitting portion (not shown) and a light receiving portion (not shown) for receiving light from the light emitting portion, and the upper side of the rotation shaft 19c of the detection lever 19a is moved from the light emitting portion by the rotation operation. The light directed to the light receiving portion is blocked and passed. Therefore, as shown in FIG. 1, when the detection lever 19a is rotated so as to be pushed upward with the passage of the sheet P, the upper side of the detection lever 19a is located above the sensor body 19b.
, The light receiving portion is brought into a light receiving state, and the passage of the paper P is detected.

Subsequently, a platen 27 and an ink jet recording head 25, which will be described in detail later, are disposed downstream of the conveyance driving roller 17a so as to face each other in the vertical direction, and the conveyance roller 17 conveys the ink below the ink jet recording head 25. The sheet P to be supported is supported by the platen 27 from below. The ink jet recording head 25 is provided on the bottom of a carriage 23 that mounts the ink cartridge 31, and the carriage 23 is in the main scanning direction (front and back direction of paper surface of FIG. 1).
The carriage reciprocates in the main scanning direction while being guided by the carriage guide shaft 33 extending in the direction.

Next, a sheet discharge section of the printer 100 is provided downstream from the ink jet recording head 25, and includes a sheet discharge driving roller 29a which is rotationally driven and a sheet discharge driven roller 29b which is freely rotatable. A paper roller 29 is provided. Therefore, the paper P printed by the inkjet recording head 25 is rotated in a state where it is nipped by the paper ejection drive roller 29a and the paper ejection driven roller 29b, so that the paper ejection direction (FIG. 1 is discharged in the direction of the arrow). Also, the paper discharge driven roller 29b
A slightly rotatable auxiliary roller 30 is arranged on the slightly upstream side.

Here, as shown in FIG. 2, a plurality of paper discharge driving rollers 29a are arranged at substantially equal intervals in the main scanning direction, and the paper discharge driven rollers 29b shown in FIG. Are arranged at substantially equal intervals. Further, the auxiliary roller 30 includes the paper discharge drive roller 29a and the paper discharge driven roller 2
It is arranged almost in the middle of 9b (not shown).

By the way, the transport roller 17 and the paper discharge roller 2
9 and 9 have the following effects. That is, as shown in FIG. 1, the nip point between the conveyance driving roller 17a and the conveyance driven roller 17b in the conveyance roller 17 is set slightly downstream, and in the paper ejection roller 29, the paper ejection drive roller 29a. And paper discharge driven roller 29b
The nip point between and is set slightly upstream. As a result, between the transport roller 17 and the paper discharge roller 29, the paper P is in a gently curved state so as to be convex downward as shown in the figure, and thereby the paper P is moved to the platen 27.
It is designed to be pressed against. As a result, the sheet P is prevented from rising from the platen 27, and the distance between the printing surface and the recording head 25 is kept constant, so that the deterioration of the printing quality can be prevented.

The above is the configuration of the paper transport path of the printer 100, and the platen 27 will be described in detail below. Figure 2
As shown in FIG. 3 and FIG. 3, the platen 2 is long in the main scanning direction (horizontal direction in FIGS. 2 and 3), and the sub-scanning direction (FIG. 2) is provided on the upper surface (hereinafter referred to as “platen surface”) 27a.
It has ribs 28a and 28b extending in the vertical direction). Here, in the present embodiment, the ribs 28a and the ribs 28b are arranged at equal intervals (about 55 mm) except for the rib 28a located closest to the 80th digit side (left direction in FIG. 2).

Here, the ribs 28a and 28b function in cooperation with the paper discharge roller 29 (FIG. 1) and the auxiliary roller 30 to forcibly generate the cockling phenomenon on the paper P. That is, in FIG. 1, when ink droplets are ejected from the recording head 25 onto the paper P, the paper P absorbs the ink droplets and swells, causing a phenomenon of waviness in the main scanning direction (cockling phenomenon). Such a cockling phenomenon may occur, for example, on the flat surface (the platen surface 27a, the rib 28
a and 28b are not formed), an irregular wavy phenomenon causes the printing surface and the recording head 2
In addition to the large variation in the distance from the print head 5, the print quality is deteriorated, and in some cases, the print surface may rub against the recording head 25 and stain the print surface.

Therefore, ribs 28a are provided on the platen surface 27a,
28b is formed, a paper discharge roller 29 is arranged in accordance with the arrangement position of the ribs 28a and 28b (see FIG. 2), and an intermediate position between the ribs 28a and 28b (two adjacent paper discharge rollers) is formed. Intermediate position 19), the auxiliary roller 3
0 was set. As a result, the top of the cock ring is rib 2
8a and 28b, the bottom portion of the cockling is formed by the auxiliary roller 30, and a cockling state having a regular cycle is formed (paper P shown by phantom lines in FIG. 3).

That is, the discharge roller 29 and the auxiliary roller 3
0 and the ribs 28a and 28b cooperate with each other to form the paper P.
A constant cycle of cockling is forcibly formed in
Therefore, a cockling state with an irregular cycle is not formed,
As a result, the distance between the print surface and the recording head 25 does not greatly vary, and thus the print quality is prevented from being degraded. Note that, in the present embodiment, as shown in FIG. 2, the transport driven roller 27, the rib 28a or 28b, and the paper discharge roller 29 are arranged in a straight line in the paper feeding direction. A regular cockling state with a constant cycle is formed in the main scanning direction.

By the way, the paper P is discharged in this way from the discharge roller 2
9, the auxiliary roller 30 and the ribs 28a and 28b cooperate to make the distance between the recording head 25 and the printing surface as uniform as possible, but the paper P does not reach the paper discharge roller 29. That is, when the leading edge of the paper P is between the transport roller 17 and the paper discharge roller 29, the above-mentioned cooperation does not work.

On the other hand, when the distance between the transport roller 17 and the paper discharge roller 29 becomes long, the platen surface 27 of the paper P is produced by the cooperation of the transport roller 17 and the paper discharge roller 29 described above.
There arises a problem that the effect of pressing on a is lost.
That is, no particular problem occurs after the leading edge of the sheet P is nipped by the sheet discharge roller 29. However, before the leading edge of the paper P is nipped by the paper discharge roller 29, the paper P is on the platen surface 27 on the side near the transport roller 17.
Although pressed against a, when the recording head ejects ink droplets onto the printing surface, the paper P expands due to the ink droplets adhering and penetrating, and as a result, the leading end of the paper that is not nipped by the paper ejection roller 29 warps upward. Then, the distance between the printing surface and the recording head 25 may become uneven.

Therefore, in the platen 27, the rib 28
The heights of a and the ribs 28b were formed so as to be different, and these were arranged almost alternately. For more details,
In the present embodiment, as shown in FIG. 3, two ribs 28a are arranged in the vicinity of a substantially central portion, and ribs 28b and 28a having different heights are arranged on the left and right sides of these two ribs 28a.
It is configured to be arranged alternately by and. Hereinafter, the operation and effect of the ribs 28a and 28b arranged in this way will be described with reference to FIG.

First, FIG. 4A shows a sheet P in a state where ink droplets are not ejected on the printing surface. As shown in the figure, the sheet P has a rib 28b having a low height due to its rigidity.
Is not supported by the ribs 28a, but is supported from below only by the ribs 28a. 4A to 4C all show the leading end portion of the paper P, that is, the leading end of the paper P has not reached the paper discharge roller 29 (FIG. 1). Next, when an ink droplet is ejected onto the printing surface, the rigidity of the paper P is lowered, and as shown in FIG. 4B, the space between the two ribs 28a drops downward, and the space between the two ribs 28a falls. It will be in a gentle curved state, and eventually it will be supported from below by the rib 28b as shown in FIG. 4 (c).

Here, the ribs 28a and 28b are the ribs 28a and 28b and the discharge roller 2 when the sheet P is nipped between the conveying roller 17 and the discharge roller 29.
9. By the cooperation of the auxiliary roller 30 (FIG. 1), the paper P
Form a regular cockling state. Then, in order to form a regular cockling state on the paper P, it is necessary to dispose two adjacent ribs at relatively small intervals.

However, in the state as shown in FIG.
The ribs 28a and 28b, the paper discharge roller 29, and the auxiliary roller 30 (FIG. 1) do not work together on the paper P while the leading edge of the paper P extends from the transport roller 17 to the paper discharge roller 29.
As a result, when the two adjacent ribs are arranged at a small interval as described above, the paper P does not fall between the two adjacent ribs due to its own weight, and the cockling state is not formed. Then, as a result, the paper P on which the ink droplets have been ejected warps upward, and the distance between the printing surface and the recording head 25 (FIG. 1) becomes non-uniform, which may deteriorate print quality.

However, as described above, in the platen 27 according to the present invention, the ribs 28a and the ribs 28b having different heights are alternately arranged (in the present embodiment, the ribs 28a and the ribs 28 are arranged).
The height difference from b is 0.3 to 0.5 mm). Therefore, the paper P that has absorbed the ink drops falls into the rib 28b having a low height as shown in FIGS.
As a result, a cockling state is formed on the paper P. That is, even if the two adjacent ribs are arranged at a relatively small interval in order to form a regular cockling, a cockling state is formed at the leading end portion of the sheet P that is not nipped by the sheet discharge roller 27. This makes it possible to prevent the leading edge of the paper P from warping upward,
Thus, it is possible to prevent the print quality from deteriorating.

The ribs 28a and the ribs 28b do not necessarily have to be alternately arranged on the platen surface 27a, and at least a part of the ribs arranged on the platen surface 27a is high as described above. If the two ribs 28a and 28b having different heights are alternately arranged, a cockling state can be formed at the leading end portion of the paper P, and thus deterioration of print quality can be prevented.

In addition, as described above, it is sufficient that the cockling state can be formed on the sheet P in the state where the sheet P is not nipped by the sheet discharge roller 29. Therefore, for example, all the ribs have the same height and are adjacent to each other. If an air suction hole or the like for sucking the back surface of the paper P is provided between the two ribs,
The cockling state can be formed on the paper P even when the paper P is not nipped by the paper discharge roller 29, and thus the same effect as that of the platen 27 according to the present embodiment can be obtained. That is, the paper P is the paper discharge roller 2
If a “cockling forming means” for forming a cockling state on the sheet P in a state where it is not nipped to the sheet 9 is provided, the same operational effect as the platen 27 according to the present embodiment described above can be obtained.

[0042]

As described above, according to the present invention, at least a part of the plurality of ribs arranged on the platen surface has the first rib and a height higher than that of the first rib. Low second ribs are alternately arranged, and while the leading end of the recording material reaches from the transport roller to the paper discharge roller,
Since the wavy state is formed at the leading end portion of the recording material on which the ink droplets are ejected by the first rib and the second rib, even if the distance between the transport roller and the paper discharge roller becomes long,
The tip of the recording material does not float up from the platen, so that the deterioration of recording quality can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view of an inkjet printer according to the present invention.

FIG. 2 is a plan view of main components (mainly platen) of a recording unit of the inkjet printer according to the present invention.

FIG. 3 is a front view of main components (mainly platen) of a recording unit of the inkjet printer according to the present invention.

FIG. 4 is a front view of the platen showing the state of the printing paper supported on the platen according to the present invention.

[Explanation of symbols]

1 Paper feeder 17 Conveyor roller 25 inkjet recording head 27 Platen 27a Platen surface 29 Paper ejection roller 30 Auxiliary roller 100 inkjet printer

Claims (6)

[Claims] 1. An inkjet recording head for recording by ejecting ink droplets onto a recording material, and a conveying roller provided upstream of the inkjet recording head for conveying the recording material to the inkjet recording head. A recording apparatus, which is provided on the downstream side of the inkjet recording head and discharges a recording material on which recording has been performed, is provided so as to face the inkjet recording head and face the inkjet recording head. A platen having a plurality of ribs extending in the sub-scanning direction at predetermined intervals in the main scanning direction on the surface to support the recording material from below by the ribs, and at least a part of the plurality of ribs. However, the first ribs and the second ribs, which are lower in height than the first ribs, are alternately arranged. A platen, wherein a corrugated state is formed at a leading end portion of a recording material on which ink droplets are ejected by the first ribs and the second ribs, between the conveyance roller and the paper discharge roller. . 2. The platen according to claim 1, wherein the ribs are arranged at equal intervals in the main scanning direction. 3. The platen according to claim 1, wherein a distance between the first rib and the second rib is 30 to 70 mm. 4. The transport driving roller according to claim 1, wherein the transport roller comprises a shaft body that is long in a main scanning direction, and the transport driving roller is driven to rotate. A plurality of conveyance driven rollers that are arranged in a plurality and are driven to rotate by being pressed against the conveyance driving roller, and a plurality of the paper discharge rollers are provided in the main scanning direction, and
A sheet discharge driving roller that is rotationally driven and arranged so that its position in the main scanning direction coincides with the transport driven roller; and a sheet discharge driven roller that rotates in contact with the sheet discharge driving roller. The platen, wherein the rib is arranged so as to coincide with the positions of the transport driven roller and the paper discharge roller in the main scanning direction. 5. An inkjet recording head that performs recording by ejecting ink droplets onto a recording material, and a conveying roller that is provided upstream of the inkjet recording head and that conveys the recording material to the inkjet recording head. A recording apparatus, which is provided on the downstream side of the inkjet recording head and discharges a recording material on which recording has been performed, is provided so as to face the inkjet recording head and face the inkjet recording head. Is a platen in which a plurality of ribs extending in the sub-scanning direction are arranged at a predetermined interval in the main scanning direction on the surface to support the recording material from below by the ribs, and the tip of the recording material is from the conveying roller. Having a cockling forming means for forming a wavy state in the main scanning direction on the recording material while reaching the paper discharge roller A platen that is characterized by 6. An inkjet recording apparatus for recording on a recording material, comprising the platen according to claim 1. Description: