JP2003191552A - Paper discharging unit and ink-jet recording apparatus comprising the paper discharging unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a paper discharging unit capable of executing a paper discharging operation without contacting the recording surface of a material to be recorded, and forming a certain cockling cycle without affecting the ink droplet impact accuracy. <P>SOLUTION: A platen 14 is disposed facing a recording head 9. The platen 14 has ribs 10 elongating in the sub scanning direction formed by a certain interval in the main scanning direction on the surface facing the recording head 9. A paper discharging driving roller 20 having suction holes on the outer circumferential surface executes the paper P discharging operation according to its rotation while vacuuming the rear surface of a paper P by the suction holes. In the paper discharging driving roller 20, the suction holes are formed in the parts corresponding to the halfway positions of the two adjacent ribs 10 such that a cockling state is formed in the paper P by a certain cycle by the ribs 10 and the suction holes. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording by ejecting ink droplets onto a recording material, and ejects the recording material on the downstream side of an inkjet recording head on which recording has been performed. Regarding a paper discharge device. Further, the present invention relates to an inkjet recording device including the paper discharge device.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, an ink jet recording head that ejects ink droplets onto a recording surface of a recording material, and a recording material that has been recorded and is disposed downstream of the ink jet recording head are discharged. And a discharge roller for discharging the same.

In an ink jet recording apparatus having a conventional general structure, the paper ejection roller nips a recording material between the paper ejection drive roller which is rotationally driven and the paper ejection drive roller. It consists of a paper discharge driven roller that is pressed against the drive roller. A so-called "gear roller" is used for the paper ejection drive roller, which comes into contact with the recording surface in a semi-dried state immediately after the ink droplets are ejected, so that the outer circumference makes point contact with the recording surface of the recording material. There is.

However, even with the use of the serrated roller, ink droplets are transferred to the serrated roller, and the transferred ink droplets are re-attached to the recording surface, thereby soiling the recording surface, that is, a trace of the serrated roller is formed. There are cases. Therefore, in order to solve such a problem, it is necessary to discharge the recording material without contacting the recording surface on which the ink droplets are ejected. Although a problem to be solved is different, as a first conventional technique, in Japanese Patent Laid-Open No. 5-138862, a paper discharge cylinder (roller body) is provided in which adsorbents for adsorbing to the back surface of the paper are radially provided with respect to a rotation axis. ) Is disclosed. According to this, particularly in an offset printing machine, the paper on which recording is performed by passing between the transfer cylinder and the impression cylinder is ejected in a state in which the back surface of the paper is adsorbed by the ejection cylinder equipped with the adsorbent. By rotating the paper cylinder, the paper can be reliably conveyed in the paper ejection direction without being deformed or scratched at the tip of the paper.

Similarly, although the problem to be solved is different,
As a second conventional technique, Japanese Patent Laying-Open No. 9-67055 discloses a paper discharge unit vacuum suction wheel (roller body) having a plurality of holes on the outer peripheral surface and sucking a sheet through the holes. According to the paper discharge unit vacuum suction car, the sheet is taken over from the conveying device that conveys the sheet by the endless chain having the chain gripper that grips the leading end of the sheet, and the sheet travels at a speed lower than the sheet conveying speed of the conveying device. Thus, the sheets can be stably stacked on the stacking device (stacker).

Further, although the problem to be solved is different,
As a third conventional technique, in Japanese Patent Laid-Open No. 10-315551, a belt-shaped body having a perforated adsorption surface for adsorbing the entire recording area of a recording material is provided to a pressure chamber connected to a negative pressure generating means. There is disclosed an inkjet recording device which is arranged so as to be relatively movable. According to the inkjet recording apparatus, an image is formed by the recording head after adsorbing the entire recording area of the recording material to the perforated adsorption surface (at this time, the belt-shaped body is in a stopped state, and the recording head is mainly used). (Image formation is performed by moving in the scanning direction and the sub-scanning direction), and after the image formation is completed, the belt-shaped body is driven to transfer the recording material, so that deterioration of print quality due to deterioration of conveyance accuracy is prevented. be able to.

If the sheet discharging operation is performed while sucking the back surface of the recording material using the suction means according to the first to third conventional techniques described above, the above-mentioned problem, that is, the ink droplet is discharged. It is possible to solve the problem that the components of the paper discharge device come into contact with the recording surface to form traces thereof.

[0008]

However, the following problems have not yet been solved in the above-mentioned prior art.
That is, in an ink jet recording apparatus, a recording material absorbs ink droplets and swells to cause a wavy phenomenon in the main scanning direction, a so-called cockling phenomenon occurs. If such a cockling phenomenon is left as it is, the variation in the distance between the recording surface and the recording head becomes large and the recording quality deteriorates. In some cases, the recording surface may be rubbed by the recording head and the recording surface may be soiled. is there. Therefore, in order to solve this,
Generally, in an inkjet recording apparatus, ribs extending in the sub-scanning direction are arranged at predetermined intervals in the main scanning direction on a platen that is arranged so as to face the recording head and defines the distance between the recording surface and the recording head. Two adjacent recording materials
A portion corresponding to an intermediate position of the two ribs is nipped by the sheet discharge driving roller and the sheet discharge driven roller. Thereby, the top of the cock ring is formed by the rib,
Similarly, since the bottom portion is formed by the paper discharge driving roller and the paper discharge driven roller, a cockling state of a constant cycle is forcibly formed on the recording material, and therefore the distance between the recording surface and the recording head varies greatly. It does not stick and the recording surface does not rub against the recording head.

Here, in the above-mentioned first and second prior arts, the problem peculiar to the above-mentioned ink jet recording apparatus, that is, the problem of cockling is not taken into consideration in adsorbing the recording material. However, it is not suitable from the viewpoint of obtaining a good recording quality simply as a sheet discharging device of an inkjet recording device.

Further, in recent years, in order to further improve the image quality, in particular, in order to realize higher quality photographic image quality, minimization of ink droplets has been advanced. In the ink jet recording apparatus for ejecting such an extremely small ink droplet, it is necessary to further improve the accuracy of landing the ink droplet on the recording surface. However, as in the third conventional technique, the landing position of the ink droplet, that is, the recording is performed. If there is a suction surface on the back side of the area, flight deviation of ink droplets may occur, which may affect landing accuracy.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to perform a paper discharge operation without contacting the recording surface of a recording material without affecting the landing accuracy of ink droplets. Another object of the present invention is to obtain a paper discharge device capable of forming a cockling state with a constant cycle.

[0012]

In order to solve the above-mentioned problems, the paper discharge apparatus according to claim 1 of the present application is an inkjet recording head for recording by ejecting ink droplets onto a recording material, and the inkjet recording. The surface provided facing the head and facing the inkjet recording head,
Inkjet recording including a platen having ribs formed so as to extend in the sub-scanning direction at predetermined intervals in the main scanning direction, and a conveyor roller that conveys a recording material under the inkjet recording head at a constant pitch. In the apparatus, a sheet discharge device that is provided on the downstream side of the inkjet recording head and discharges a recording material recorded by the inkjet recording head by a sheet discharge driving roller that is rotationally driven. The drive roller has a hollow portion that communicates with the air suction means and a plurality of suction holes that are provided in the outer peripheral surface of the roller and that communicate with the hollow portion. The suction holes suction and rotate the back surface of the recording material. By doing so, the recording material is discharged, and the suction holes are adjacent to each other on the back surface of the recording material that has passed through the rib.
It is characterized in that it is formed so as to adsorb a portion corresponding to an intermediate position of the two ribs.

According to the first aspect of the present invention, the recording surface is not soiled or scratched by performing the paper discharge operation without contacting the recording surface of the recording material, and at the same time, the recording material is at the same time. Since a proper cockling state is formed on the recording medium, the distance between the ink jet recording head and the recording surface does not greatly vary, and it is possible to realize appropriate recording quality.

That is, a platen is provided so as to face the ink jet recording head, and a paper discharge drive roller that is driven to rotate is provided downstream of the platen.
The discharge driving roller has a suction hole on the outer peripheral surface, and the inside is a hollow portion communicating with the suction hole. Since the hollow portion communicates with the air suction means provided outside, the back surface of the recording material is adsorbed by the suction hole and adheres closely to the paper ejection drive roller, and the paper ejection drive roller rotates in this state. Thus, the recording material is ejected. As described above, the recording surface of the recording material is not contacted during the paper discharging operation, and the recording surface is not soiled or scratched.

Next, although the platen is provided with ribs, in the paper ejection drive roller, the suction holes adsorb a portion of the back surface of the recording material corresponding to an intermediate position between two adjacent ribs. Is formed. Therefore, the ribs formed on the platen form the top of the cock ring, and the suction portion of the suction hole forms the bottom of the cock ring, thereby forming a constant cycle of the cock ring. As described above, an appropriate recording quality can be obtained without causing a large variation in the distance between the recording material recording surface and the inkjet recording head.

The recording material is adsorbed by a paper ejection drive roller located downstream of the ink jet recording head. Therefore, unlike the configuration in which the recording material is adsorbed at the position facing the ink jet recording head, it does not affect the landing accuracy of the ink droplets, and thus in the case of using extremely small ink droplets for high image quality. Also, the desired recording quality can be obtained.

According to a second aspect of the present invention, there is provided the paper discharge device according to the first aspect.
In the paper discharge drive roller, a concave-convex shape is formed along the longitudinal direction such that a portion corresponding to the disposition position of the rib is a mountain and a portion corresponding to an intermediate position between two adjacent ribs is a valley. It is characterized by doing. Claim 2 of the present application
According to the invention described above, in the discharge driving roller, a portion corresponding to a disposition position of the rib is a mountain and a portion corresponding to an intermediate position of two adjacent ribs is a trough. Since the projections and depressions of the concave and convex shapes are on the top of the cock ring and the concave and convex portions of the concave and convex shape are the bottom of the cock ring, the recording material is further formed with a constant cycle of the cock ring. As a result, the distance between the recording surface of the recording material and the inkjet recording head does not vary further, and more appropriate recording quality can be obtained.

According to a third aspect of the present invention, there is provided the paper discharge device according to the second aspect.
In the above, the suction hole is provided so as to further adsorb a portion corresponding to the rib on the back surface of the recording material that has passed through the rib. According to the third aspect of the present invention, since the back surface of the recording material that has passed through the ribs is formed so as to further adsorb the portion corresponding to the ribs, therefore, the unevenness of the above-described paper discharge drive roller is provided. The recording material that comes into contact with the convex portion of the shape, that is, the top of the cockling is also adsorbed, and thus the above-mentioned claim 2 of the present application.
It is possible to more reliably obtain the action and effect of the invention described above, and by further providing the suction hole, a larger suction force can be obtained, so that the recording material can be reliably discharged with a larger force. It becomes possible to make paper.

According to a fourth aspect of the present invention, there is provided a paper discharge device according to the first aspect.
In the above, the suction hole is formed so as to further adsorb the portion corresponding to the rib on the back surface of the recording material that has passed through the rib, and the portion corresponding to the rib is roughly adjacent to each other. It is characterized in that a portion corresponding to an intermediate position of the rib is formed so as to be dense. According to the invention of claim 4, the suction hole is formed so as to further adsorb a portion corresponding to the rib on the back surface of the recording material that has passed through the rib, and corresponds to the rib. Since the portions are roughly formed and the portions corresponding to the intermediate positions of the two adjacent ribs are densely formed, the ribs and the portions corresponding to the intermediate positions of the two adjacent ribs are densely formed. A constant cockling cycle is formed by the suction holes formed in the above, and in addition to this, the cockling top is lightly sucked by the suction holes roughly formed in the portion corresponding to the rib, so that a larger suction A force can be obtained, and thus the recording material can be reliably ejected with a larger force.

According to a fifth aspect of the present invention, there is provided a paper discharge device according to the first aspect.
1 to 4, the suction hole is formed so as to adsorb both side end portions of the back surface of the recording material. According to the fifth aspect of the present invention, the recording surface is not rubbed against the nozzle surface of the inkjet recording head due to the adsorption of both side edge portions of the recording material that is particularly likely to float, and good recording results can be obtained. it can.

According to a sixth aspect of the present invention, there is provided a paper discharge device according to the first aspect.
5 to 5, the suction hole is continuously formed along the outer periphery of the paper discharge drive roller,
It is characterized by According to the invention of claim 6 of the present application,
Since the suction holes are continuously drilled along the outer circumference,
Therefore, there is no portion where the recording material is not adsorbed even when the paper discharge drive roller rotates, so that a reliable paper discharge operation can be performed and an ideal cockling state can be reliably formed. it can.

According to a seventh aspect of the present invention, there is provided a paper discharge device according to the first aspect.
1 to 6, a guide member having a guide surface that guides the leading end of the recording material to the downstream side is provided on the downstream side of the paper discharge drive roller in the vicinity of the outer peripheral surface of the paper discharge drive roller. It is characterized by According to the invention of claim 7 of the present application, there is a guide member on the downstream side of the paper discharge drive roller that is close to the paper discharge drive roller and guides the recording material front end to the downstream side. By being guided by the guide surface, it is possible to prevent the recording material from being wound around the paper discharge drive roller and becoming a paper jam.

According to the eighth aspect of the present invention, there is provided the paper discharge device according to the seventh aspect.
In the above, the guide surface is an inclined surface with the traveling direction of the recording material facing upward.

According to the invention of claim 8 of the present application, the guide surface provided near the downstream side of the paper discharge drive roller for guiding the recording material to the downstream side of the discharge path is directed upward. The recording material is pressed against the platen located on the upstream side of the roller, so that the distance between the recording surface and the inkjet recording head becomes stable, and good recording results can be obtained.

According to a ninth aspect of the present invention, there is provided a paper discharge device according to the first aspect.
In any one of the items 1 to 8, the air suction means includes an air exhaust port, and the air exhaust port is provided so as to exhaust air toward the recording surface of the recording material downstream of the paper discharge drive roller. It is characterized by being According to the invention of claim 9 of the present application, since the air exhaust port is arranged in the state of being directed toward the recording surface of the recording material on the downstream side of the paper discharge drive roller, the advancing direction of the recording material is thereby set. Becomes downwards,
When a paper discharge stacker is provided in the lower part, the recording material is appropriately dropped onto the paper discharge stacker, and at the same time, the coated recording surface is quickly dried by ejecting ink droplets. As a result, it is possible to obtain the effect of keeping the recording surface clean.

The paper discharge device according to claim 10 of the present application is provided with an ink jet recording head for performing recording by ejecting ink droplets onto a recording material, and facing the ink jet recording head, and facing the ink jet recording head. A platen having ribs formed so as to extend in the sub-scanning direction on the surface to be formed at a predetermined interval in the main scanning direction,
In an inkjet recording apparatus including a transport roller that transports a recording material under the inkjet recording head at a constant pitch, the inkjet is driven by a discharge driving roller that is provided downstream of the inkjet recording head and is driven to rotate. A discharge device for discharging a recording material on which recording is performed by a recording head, wherein the discharge driving roller is formed so as to extend in a circumferential direction on a hollow portion communicating with an air suction means and an outer peripheral surface of the roller. A suction groove that communicates with the hollow portion, and is configured to perform a paper discharge operation of the recording material by sucking and rotating the back surface of the recording material by the suction groove. Is formed so as to adsorb a portion corresponding to an intermediate position of two adjacent ribs on the back surface of the recording material that has passed through the ribs.

According to the tenth aspect of the present invention, a paper discharge drive roller having a suction groove for sucking the back surface of the recording material is disposed downstream of the ink jet recording head, and
Since the suction groove is formed so as to suck a portion corresponding to an intermediate position between two adjacent ribs on the back surface of the recording material that has passed through the ribs, the same as the above-mentioned invention of claim 1 of the present application. Various operational effects can be obtained.

An ink jet recording apparatus according to an eleventh aspect of the present invention is characterized by including the paper discharge apparatus according to any one of the first to tenth aspects. According to the invention described in claim 11 of the present application, it is possible to obtain the same operational effect as that of the invention described in any one of claims 1 to 10 of the present invention in the inkjet recording apparatus.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, a general structure of an inkjet printer (hereinafter referred to as “printer”) 1 as an “inkjet recording device” according to the present invention will be described with reference to FIG. Here, FIG. 1 is a schematic side sectional view of the printer 1 according to the present invention. In FIG. 1, the printer 1 includes a paper feed unit 2, a recording unit 3, and a paper discharge unit (paper discharge device) 4.

The paper feeding unit 2 includes a hopper 5 and a paper feeding roller 6. The hopper 5 supports the paper P as a "recording material" in an inclined posture as shown in the drawing, and is provided so as to be rotatable around a rotation shaft 5a.
The lower part can be pressed against and separated from the paper feed roller 6. That is, when a paper feeding operation is performed in a state where a plurality of paper sheets P are accumulated, the paper feeding roller 6
The uppermost sheet P is brought into a state of being capable of being fed by being pressed against the sheet P, and is separated from the sheet feeding roller 6 so that a conveyance load (back tension) of the sheet P is not generated during a recording operation by the recording unit 3 described later. Become.

The recording unit 3 provided downstream of the paper feeding unit 2 is
The transport roller 7, the platen 14, and the carriage 8 (inkjet recording head 9) are provided. The transport roller 7 is composed of a transport drive roller 7a that is rotationally driven and a transport driven roller 7b that is freely rotatable.
The sheet P is nipped by a and the conveyance driven roller 7b, and the conveyance driving roller 7a is rotationally driven to convey the sheet P to the downstream side at a constant pitch.

A platen 14 and an ink jet recording head (hereinafter referred to as “recording head”) 9 are arranged downstream of the conveying roller 7. The recording head 9 is the carriage 8
The ink is supplied from an ink cartridge (not shown) provided on the bottom of
Ink droplets are ejected on. The carriage 8 is provided so as to reciprocate in the main scanning direction (the front and back direction of the paper surface of FIG. 1) by a drive mechanism (not shown), and the reciprocating movement in the main scanning direction and the sub-scanning direction of the paper P by the transport roller 7 ( (Left direction in Figure 1)
The recording on the paper P is performed by moving to. The platen 14 is arranged to face the recording head 9 and
The distance between the recording surface of the sheet P and the recording surface of the sheet P is defined. The detailed configuration of the platen 14 will be described later.

The paper discharge unit 4 provided downstream of the recording unit 3 is
The paper ejection drive roller 20, the guide member 26, and the paper ejection stacker 12 are provided. The paper ejection drive roller 20 is rotationally driven, and the back surface of the paper P is adsorbed by the adsorption means described later, and the paper P is ejected by rotating in the adsorbed state. The guide member 26 is provided downstream of the paper discharge drive roller 20 and close to the paper discharge drive roller 20, and has a function of guiding the discharged paper P, in particular, the front end of the paper P to the downstream side. The details of the discharge driving roller 20 and the guide member 26 will be described later. The paper output stacker 12 is provided below the guide member 26, and the recorded paper P is
The sheets are discharged to the sheet stacker 12 and stacked. The above is the general configuration of the printer 1.

Next, the details of the platen 14 and the paper discharge unit 4 will be described with reference to FIGS. here,
FIG. 2 is a plan view of the platen 14, and FIG. 3 is a side view of a traveling path of the paper P from the transport roller 7 to the guide member 26. 4 is a longitudinal sectional view of the paper ejection drive roller 20, FIGS. 5 to 7 are plan views (enlarged views) of the paper ejection drive roller 20, and FIG. 8 is a longitudinal sectional view of the paper ejection drive roller 20. (Enlarged view).

First, as shown in FIG. 2, the platen 14 is long in the width direction of the paper P (main scanning direction: left and right direction in FIG. 2), and the upper surface (the surface facing the recording head 9) is sub-scanned. Ribs extending in the direction (vertical direction in FIG. 2) are arranged at regular intervals in the main scanning direction. The ribs 10 are formed so as to cover an area in which the nozzle surface 13 of the recording head 9 performs main scanning (an area in which the nozzle surface 13 reciprocates in the left-right direction in FIG. 2), and as shown in FIG. It defines the distance from P.

More specifically, as shown in FIG. 3, the rotation center of the transport driven roller 7b provided upstream of the platen 14 is set slightly downstream of the rotation center of the transport drive roller 7a. Thus, the traveling direction of the paper P proceeding downstream from the nip point between the transport driving roller 7a and the transport driven roller 7b is slightly downward, and the paper P is pressed against the rib 10. Therefore, the paper P is the rib 10
The recording surface of the paper P and the rib 10
The distance between and will be kept constant and appropriate recording quality will be obtained.

Further, a guide member 26 having a guide surface 26a close to the outer peripheral surface of the sheet discharge driving roller 20 is disposed downstream of the sheet discharge driving roller 20 which will be described in detail later. As shown in FIG. 3, the guide surface 26a is an inclined surface that is directed upward in the paper discharge direction (advancing direction) of the paper P. Further, as will be described later in detail, the paper discharge drive roller 20 is a sheet. Since the back side of the sheet P is attracted, the sheet P
Is pressed against the rib 10, and the recording surface of the paper P and the rib 1
The distance from 0 is kept constant. In particular, the above-described effect of pressing the paper P against the rib 10 by the transport driving roller 7a and the transport driven roller 7b is effective in a state where the leading end of the paper P has not reached the paper discharge driving roller 20, and is guided. The effect of pressing the surface 26a and the paper discharge drive roller 20 against the rib 10 of the paper P is effective when the rear end of the paper P is free from the transport drive roller 7a and the transport driven roller 7b. .

Next, the structure of the paper discharge drive roller 20 will be described in detail. In FIG. 4, bearings 23, 23 are provided on the frame members 22, 22 which are the base of the printer 1, and both shaft ends of the paper discharge drive roller 20 which is a small diameter portion are the bearings 2.
It is pivotally supported by 3, 23. Further, the paper discharge drive roller 20 is rotatably driven by a drive motor and a power transmission mechanism (not shown).

The paper discharge driving roller 20 has a hollow portion 21 inside, and one shaft end (the left shaft end in FIG. 4) is a closed end and the other shaft end (in FIG. 4). The right shaft end) is the open end 24. The open end 24 is "air suction means"
Connected to the fan device 25 as
The so-called negative pressure is generated in the hollow portion 21 by the operation of. The fan device 25 may be any device as long as it can generate a negative pressure in the hollow portion 21 by sucking air. Therefore, it may be a so-called vacuum suction pump device.

Next, a suction hole communicating with the hollow portion 21 is formed on the outer peripheral surface of the paper discharge drive roller 20. Figure 5 (A)
Shows the suction holes, and small-diameter suction holes denoted by reference numeral 28 are formed so as to be densely arranged at a predetermined interval in the axial direction of the paper discharge drive roller 20. Suction hole 2
In FIG. 5 (A), the density of 8 is the discharge driving roller 2
The outer circumference of 0 is drilled so as to make one round at regular intervals, and the two holes are made so as to be arranged so as to be alternately arranged along the outer circumference. It is set up.

Therefore, when the fan device 25 operates, negative pressure is generated in the hollow portion 21, and the suction hole 28 can adsorb the back surface of the paper P. Then, the rear surface of the paper P is attracted to the outer peripheral surface of the paper ejection drive roller 20 and is rotated to drive the paper ejection drive roller 20, so that the recording surface of the paper P (the surface facing the recording head 9) is not contacted. It is possible to perform the paper discharge operation of the paper P. Further, since the suction hole 28 is provided at a position apart from the position facing the recording head 9, even if the suction operation is performed by the fan device 25,
There is no influence on the landing accuracy of the ink droplets ejected from the recording head 9, and thus desired recording quality can be obtained even when a very small ink droplet is used for high image quality.

By the way, in relation to the rib 10 formed on the platen 14, the suction hole 28 has an intermediate position (reference numeral 27a) between two adjacent ribs 10 as shown in FIG. 5 (A).
The holes are formed so as to be densely packed in a portion corresponding to the position indicated by. FIG. 8 shows a suction hole 2 formed as shown in FIG.
8 is a view showing the positional relationship between the ribs 8 and the ribs 10 in the main scanning direction by a cross-sectional view of the paper P and the paper ejection drive roller 20 (a view from the downstream side to the upstream side). As shown,
Since the suction hole 28 is provided at an intermediate position between the two adjacent ribs 10, the back surface of the sheet P is sucked by the suction hole 28, so that the suction portion by the suction hole 28 and the rib 10 are attracted.
A cockling state with a constant period is forcibly formed by. Therefore, even if the paper P ejects ink droplets from the nozzle surface 13 and expands by absorbing the ink droplets, a non-uniform wavy state is not formed,
The variation in the distance between the nozzle surface 13 and the paper P is kept constant. In FIG. 6, the alternate long and short dash line H indicates the height level of the nozzle surface 13.

Furthermore, the suction holes 28 are formed in the sheet discharge drive roller 20 so as to suck the side edge portions of the sheet P (portions indicated by reference numerals 31 and 32 in FIG. 2). Therefore, this prevents the both end portions of the paper P from floating, and prevents the paper P from rubbing against the recording head 9.

Therefore, according to the above, the two adjacent ribs 1
As for the suction holes 28 formed in the portion corresponding to the intermediate position of 0 and the portions corresponding to both side end positions of the paper P, any shape and arrangement can be used as long as the back surface of the paper P can be sucked. May be For example, as shown in FIG. 5B, a groove shape extending in the circumferential direction may be used. In FIG. 5B, reference numeral 29 is a groove extending in the circumferential direction, and as shown in the drawing, the grooves are alternately formed along the circumferential direction and communicate with the hollow portion 21.

In addition, the outer peripheral shape of the discharge driving roller 20 and the suction hole 28 may be as shown in FIGS. 6 (A), 6 (B) or 7. In FIG. 6, the discharge driving roller 20 is provided at a portion (reference numeral 27) corresponding to the disposition position of the rib 10.
In the longitudinal direction (sheet discharge drive roller 20), the portion indicated by a) becomes a peak and the portion corresponding to the intermediate position between two adjacent ribs 10 (the portion indicated by reference numeral 27b) becomes a valley.
6 (A) shows a stepped shape, and FIG. 6 (B) shows the uneven shape formed by a smooth curved shape. By doing so, the uneven convex portion becomes the top of the cockling of the paper P, and the concave concave portion becomes the bottom of the cockling of the paper P, so that the paper P is more likely to be formed with a constant cycle cockling. As a result, the distance between the printing surface of the paper P and the recording head 9 (see FIG. 3) does not vary further, and a more appropriate printing result can be obtained.

Further, in FIGS. 6A and 6B, not only the portion corresponding to the intermediate position between two adjacent ribs 10 but also the portion corresponding to the rib 10 is further adsorbed on the back surface of the sheet P. Since the suction holes 28 are formed like this, therefore, the convex-concave portion, that is, the top of the cockling is also adsorbed, so that a more constant cycle of the cockling can be formed. At the same time, by further providing the suction hole 28, a larger suction force can be obtained as compared with the configuration shown in FIG. 5 (A), and thus the sheet P is reliably discharged with a larger force. It becomes possible to do.

Further, in FIG. 7, the suction holes 28 are formed by the two adjacent ribs 1 on the back surface of the sheet P which has passed through the ribs 10.
The portion corresponding to the intermediate position of 0 and the portion corresponding to the rib 10 are formed so as to be adsorbed, and the portion corresponding to the rib 10 roughly corresponds to the intermediate position between two adjacent ribs 10. It is drilled so that the parts are dense. Therefore, a constant cockling cycle is formed by the rib 10 and the suction holes 28 densely formed in the portion corresponding to the intermediate position between the two adjacent ribs 10, and in addition to this, the portion corresponding to the rib 10 is further formed. The roughly formed suction holes 28 lightly suck the top of the cockling, so that a larger suction force can be obtained, and the paper P can be reliably discharged with a larger force. Needless to say, the perforation form (the number or size of the holes) of the suction holes 28 shown in FIGS. 5 to 7 is an example, and the present invention is not limited to this embodiment.

As described above, the suction holes 28 are formed in accordance with the cockling cycle of the paper P along the axial direction of the paper discharge drive roller 20, in other words, the arrangement interval of the ribs 10, so that the suction holes 28 are formed appropriately. It is possible to obtain excellent print results.

Since the suction ports 28 (suction grooves 29) shown as an example in FIGS. 5 to 7 are continuously formed along the outer circumference in the densely packed portion as described above, As a result, even if the paper ejection drive roller 20 rotates, there is no part that does not adsorb the back surface of the paper P. Therefore, the paper P is reliably adsorbed to reliably eject the paper P, and It is possible to form a constant cycle cockling state.

By using the air exhaust port of the fan device 25, it is possible to efficiently discharge the paper P. FIG. 9 is a side view of a recording unit showing another embodiment of the printer 1. Note that, in FIG. 9, the same components as those of the printer 1 according to the above-described embodiment are denoted by the same reference numerals, and therefore the description thereof will be omitted below. In FIG. 9, an air exhaust port 30 of the fan device 25 is provided above the guide member 26 toward the recording surface of the paper P. Since the paper discharge stacker 12 is provided below the guide member 26 (see FIG. 1),
The sheet P whose traveling direction is upward by the guide member 26 is downward due to the exhaust from the air exhaust port 30, and the sheet P can be surely dropped to the sheet discharge stacker 12 located at the lower portion. Also, since ink droplets are ejected from the recording head 9, it is possible to accelerate the drying of the recording surface by exhausting air from the air exhaust port 30, and to prevent the recording surface from becoming dirty due to the transfer of ink. Is possible.

[0051]

As described above, according to the present invention, the recording surface is not contaminated or scratched by performing the paper discharge operation without contacting the recording surface of the recording material, and at the same time, Since an appropriate cockling state is formed on the recording material, the distance between the ink jet recording head and the recording surface does not greatly vary, and it is possible to realize appropriate recording quality. Further, since the suction hole of the recording material is not provided at the position facing the ink jet recording head, it does not affect the accuracy of landing the ink droplet.

[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 a platen of the inkjet printer according to the present invention.

FIG. 3 is a side view of a paper advancing path from a conveyance roller to a guide member of the inkjet printer according to the present invention.

FIG. 4 is a longitudinal cross-sectional view of a paper discharge drive roller according to the present invention.

FIG. 5A is a plan view of a paper ejection drive roller according to this embodiment, and FIG. 5B is a plan view of a paper ejection drive roller according to another embodiment.

FIG. 6 is a plan view of a paper ejection drive roller according to another embodiment.

FIG. 7 is a plan view of a paper ejection drive roller according to another embodiment.

FIG. 8 is a longitudinal cross-sectional view (including ribs) of the paper discharge drive roller according to the present invention.

FIG. 9 is a side view of a paper advancing path from a conveying roller to a guide member according to the present invention, which shows another embodiment.

[Explanation of symbols]

1 inkjet printer 2 paper feeder 3 recording section 4 Paper output section 7 Conveyor rollers 9 Inkjet recording head 10 ribs 14 Platen 20 Paper ejection drive roller 25 fan device 26 Guide member 28 Suction hole 30 air outlet P printing paper

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65H 29/22 B65H 29/52 29/52 B41J 3/04 101Z F term (reference) 2C056 EA16 HA28 HA29 HA33 2C058 AB17 AB18 AC07 AE02 AF04 AF25 AF31 DA11 DA34 2C059 AA04 AA05 AA22 AA26 CC02 CC11 CC21 DD05 DD13 3F049 AA10 CA06 LA01 LB03 3F101 FB12 LA01 LB03

Claims (11)

[Claims] 1. An ink jet recording head for performing recording by ejecting ink droplets onto a recording material, and an ink jet recording head provided opposite to the ink jet recording head and extending in the sub-scanning direction on a surface facing the ink jet recording head. In the inkjet recording apparatus, the inkjet recording apparatus is provided with a platen in which ribs formed in this manner are formed at predetermined intervals in the main scanning direction, and a conveyance roller that conveys the recording material under the inkjet recording head at a constant pitch. A discharge device for discharging a recording material recorded by the inkjet recording head by a discharge driving roller which is provided on a downstream side of the recording head and is rotationally driven, wherein the discharge driving roller is an air discharge device. A hollow portion communicating with the suction means, and a plurality of suction holes formed in the outer peripheral surface of the roller and communicating with the hollow portion. The suction hole is configured to suck and rotate the back surface of the recording material to eject the recording material, and the suction hole is provided on the back surface of the recording material that has passed through the rib. A sheet discharging device, wherein the rib is formed so as to adsorb a portion corresponding to an intermediate position between two adjacent ribs. 2. The sheet discharging drive roller according to claim 1, wherein a portion corresponding to a position where the ribs are arranged is a mountain and a portion corresponding to an intermediate position between two adjacent ribs is a valley. A paper discharge device having an uneven shape along the longitudinal direction. 3. The ejection device according to claim 2, wherein the suction hole is formed so as to further adsorb a portion of the back surface of the recording material that has passed through the rib, the portion corresponding to the rib. Paper equipment. 4. The portion according to claim 1, wherein the suction hole is formed so as to further adsorb a portion corresponding to the rib on the back surface of the recording material that has passed through the rib, and a portion corresponding to the rib. Is roughly provided such that a portion corresponding to an intermediate position between two adjacent ribs is densely formed. 5. The paper ejection device according to claim 1, wherein the suction holes are formed so as to adsorb both side end portions of the back surface of the recording material. 6. The paper discharge device according to claim 1, wherein the suction hole is continuously formed along an outer circumference of the paper discharge drive roller. 7. The guide according to claim 1, which guides a leading end of a recording material to a downstream side of the paper discharge drive roller in the vicinity of an outer peripheral surface of the paper discharge drive roller. A paper discharge device, wherein a guide member having a surface is provided. 8. The sheet discharging device according to claim 7, wherein the guide surface is an inclined surface with the traveling direction of the recording material facing upward. 9. The air suction means according to claim 1, wherein the air suction means includes an air exhaust port, and the air exhaust port is directed toward a recording surface of a recording material downstream of the paper discharge drive roller. A paper discharge device, which is provided so as to exhaust the air. 10. An ink jet recording head for performing recording by ejecting ink droplets onto a recording material, and an ink jet recording head provided opposite to the ink jet recording head and extending in the sub-scanning direction on a surface facing the ink jet recording head. In the inkjet recording apparatus, the inkjet recording apparatus is provided with a platen in which ribs formed in this manner are formed at predetermined intervals in the main scanning direction, and a conveyance roller that conveys the recording material under the inkjet recording head at a constant pitch. A discharge device for discharging a recording material recorded by the inkjet recording head by a discharge driving roller which is provided on a downstream side of the recording head and is rotationally driven, wherein the discharge driving roller is an air discharge device. The hollow part communicating with the suction means and the outer peripheral surface of the roller are formed so as to extend in the circumferential direction. A suction groove communicating with the hollow portion, and the suction groove is configured to perform a sheet discharging operation of the recording material by adsorbing and rotating the back surface of the recording material. A sheet discharging device, which is formed so as to adsorb a portion corresponding to an intermediate position between two adjacent ribs on the back surface of the recording material that has passed through the ribs. 11. An ink jet recording apparatus comprising the paper discharge device according to any one of claims 1 to 10.