JP2002225367A - Unit for fixing sheet discharge driven roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a unit for fixing a sheet discharge driven roller in an ink jet recorder where the possibility of damaging high image quality recording is low. SOLUTION: A sheet discharge driven roller 56 having a columnar shape comprises a bearing part 12 injection molded of resin, and a soft rubber roller 11. A shaft 13 is inserted into the shaft hole 121, and the sheet discharge driven roller 56 is supported rotatably on the shaft 13. The sheet discharge driven roller 56 is pressed against a sheet discharge drive roller 55 with a specified load and touches the recording surface of a recording sheet P under collapsed and deformed state. Since the area of the nip surface is enlarged, the sheet discharge drive roller 55 touches the recording sheet P over a wide area to discharge the recording sheet P surely. Furthermore, a force is not applied locally to the surface of not completely dried ink because the sheet discharge driven roller 56 touches the recording surface of the recording sheet P over a wide area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head which reciprocates in a main scanning direction, discharges ink onto a recording material, conveys the recording material intermittently in a sub-scanning direction, and performs recording. The present invention relates to an ink jet recording apparatus in which a recording material is discharged by a discharge roller.

[0002]

2. Description of the Related Art In general, an ink jet recording apparatus comprises:
As a paper discharge mechanism for discharging the recording paper after recording, a paper discharge roller including a paper discharge drive roller and a paper discharge driven roller is provided. The rotation of the paper ejection drive roller is controlled by a rotational driving force source such as a stepping motor so as to rotate in contact with the surface of the recording paper opposite to the recording surface. The paper discharge driven roller is urged by the paper discharge drive roller, is in contact with the recording surface of the recording material, and is rotatably supported by the discharge of the recording material. Then, the recording paper is discharged by the rotation control of the discharge driving roller while being sandwiched between the discharge driving roller and the discharge driven roller.

In an ink jet recording apparatus, recording is performed by discharging ink from a recording head onto a recording surface of recording paper. The ink ejected to the recording paper is liquid at that time, and gradually dries with the passage of time, and becomes completely dried when a certain time or more elapses. When discharging the recording paper after recording, if the ink discharged on the recording surface is completely dried and then discharged, the recording surface is not likely to be affected by the discharge driven roller, but the throughput of the recording execution is reduced. It will be extremely reduced.

Therefore, in general, in an ink jet recording apparatus, the recording paper is discharged in a semi-dry state during drying, without waiting for the ink discharged on the recording surface of the recording paper to completely dry. Configuration. Therefore, the paper discharge driven roller comes into contact with the semi-dry recording surface.

[0005] Therefore, the paper discharge driven roller of the conventional ink jet recording apparatus has a plurality of teeth around the teeth, and the teeth are sharply pointed so that the tips of the teeth come into point contact with the recording surface of the recording material. The roller is attached. The toothed roller is also called a knurled roller or a star wheel, and makes contact with the recording surface not at the surface but at a point. The purpose is to minimize the influence of the semi-dry ink on the recording surface.

FIG. 8 is a perspective view showing a paper discharge roller by a conventional paper discharge driven roller using a toothed roller.

The discharge drive roller 55 is rotationally controlled in the direction indicated by reference numeral B by a rotation drive force source (not shown). The paper ejection driven roller 56 is urged by the paper ejection drive roller 55 by urging means (not shown), and presses the recording paper P against the paper ejection drive roller 55. The recording paper P is sandwiched between a discharge driving roller 55 and a discharge driven roller 56,
Since the sheet is pressed against the sheet ejection drive roller 55, the sheet ejection drive roller 55 rotates in the direction indicated by the reference numeral B, and is ejected in the sub-scanning direction Y. Discharge driven roller 56
Has a configuration in which the toothed roller 21 is rotatably supported on the rotating shaft 13, and the recording paper P is moved in the direction indicated by the symbol C in a state where only the tooth tip is in contact with the recording paper P. Rotates following the paper ejection.

[0008]

The ink on the recording surface in a half-dry state during drying, that is, the surface of the ink is dry, but the inside still remains liquid. Therefore, the recording surface in a semi-dry state is unstable, and when a force is applied locally, the recording surface is easily deformed even with a slight force, and is dried while deformed, thereby deteriorating the image quality. Further, in some cases, the dry surface is torn and the liquid ink flows out, whereby the recording surface is stained and the image quality is deteriorated.

In the conventional paper discharge driven roller 56, the pointed tip of the roller comes into point contact with the recording surface of the recording paper P during the drying of the ink, and therefore, the recording surface is indicated by the symbol D (FIG. 8). There is a trace of the contact of the tooth tip. The trace that this tooth tip touched,
It is not so noticeable that the recording quality deteriorates significantly,
Conventionally, it was assumed that there was no problem. However, with the remarkable improvement in image quality of the ink jet recording apparatus in recent years, the trace of the tooth tip attached to the recording surface by the toothed roller 21 cannot be ignored.

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and an object thereof is to provide a paper ejection driven roller mounting device in an ink jet type recording device which is less likely to impair high-quality recording. is there.

[0011]

According to a first aspect of the present invention, an ink is ejected from a recording head that reciprocates in a main scanning direction onto a recording material.
The recording material is intermittently conveyed in the sub-scanning direction to perform recording, and a discharge drive roller that is rotated and controlled in contact with a surface opposite to a recording surface of the recording material; A discharge roller which is urged and in contact with the recording surface of the recording material during drying of the ink, and which is rotatably supported by the discharge of the recording material so as to be rotatably supported. A discharge driven roller mounting device for an ink jet recording apparatus from which the recording material is discharged, wherein the discharge driven roller is
Form a cylindrical body surface contact with the recording surface of the recording material,
The contact surface pressure at the nip surface where the discharge driven roller comes into surface contact with the recording surface of the recording material is required to transport the recording material from the recording head to the nip surface of the discharge roller. Determined from the time, the ink being dried on the recording surface of the recording material during drying is set to a height at which the ink can be discharged without adhering to the discharge driven roller. This is a discharge driven roller mounting device.

As described above, since the discharge driven roller has a cylindrical shape and is in surface contact with the recording surface, the recording surface in the semi-dry state during drying is not locally applied, and the drying is performed. There is no local deformation of the recording surface in the middle.

The contact surface pressure at the nip surface of the paper discharge driven roller is set at a height at which ink during drying can be discharged without adhering to the paper discharge driven roller.
The ink adhered to the discharge driven roller does not stain the recording surface. Here, the nip surface indicates a surface where the outer peripheral surface of the paper discharge drive roller and the outer peripheral surface of the paper discharge driven roller are in contact.

The fact that the ink being dried is a contact surface pressure at which the ink does not adhere to the paper discharge driven roller means that the contact surface pressure is such that the dried surface of the ink being dried is not broken. It is. That is, unless the dried surface of the ink being dried is broken, the liquid ink inside does not flow out, and the recording surface is not stained thereby. The contact surface pressure is the time required for the recording material to be transported from the recording head to the nip surface of the discharge driven roller, because the strength of the dried ink surface varies depending on the drying state of the ink, that is, It is determined by the elapsed time since the ink was ejected.

Strictly speaking, the elapsed time is measured from a nozzle disposed at the most downstream side in the sub-scanning direction of the ink jet nozzle mounted on the recording head, to the most upstream end in the sub-scanning direction of the nip surface of the paper discharge roller. This is the time required for the recording material to be conveyed up to, but in practice, if the contact surface pressure is set with some margin, it can be adjusted from near the center of the recording head to near the center of the nip surface of the discharge roller. It can be said that there is no problem with the time until the elapsed time.

Thus, according to the paper discharge driven roller mounting apparatus according to the first aspect of the present invention, it is possible to provide a paper driven driven roller mounting apparatus which is less likely to impair high-quality recording in an ink jet recording apparatus. Is obtained.

According to a second aspect of the present invention, in the first aspect, the discharge driven roller mounting device is configured so that the characteristic of the recording material, the characteristic of the ink, and the characteristic of the ink so that the contact surface pressure is obtained. A paper ejection driven roller mounting device characterized in that it is urged by a load determined from a correlation between the contact surface width of the paper ejection driven roller and the hardness of the paper ejection driven roller.

The characteristics of the ink used in the ink jet recording apparatus vary depending on the type thereof, and the time required for complete drying also varies. Further, the recording material has a different ink absorption rate on the surface depending on its type, and accordingly the drying time of the ink also differs. In other words, the time required for the ink on the recording surface to be completely dried takes a certain amount of time, and differs depending on the characteristics of the ink and the characteristics of the recording material. Therefore, the drying rate of the ink from the time when the ink is ejected on the recording surface of the recording material to the time when the ink reaches the nip surface of the paper discharge roller differs depending on the type of the ink and the type of the recording material. And
If the drying rate of the ink is different, the appropriate contact surface pressure is naturally different, and the load applied to the discharge driven roller is also different.

On the other hand, the contact surface pressure of the paper discharge driven roller urged by a constant load varies depending on the area of the contact surface. The area of the contact surface varies depending on the deformation ratio of the paper driven driven roller due to the urging force, and even with the urging force due to the same load, if the hardness of the paper driven driven roller is different, the deformation ratio is different. It will be different. Therefore, the area of the contact surface of the paper ejection driven roller depends on the width of the contact surface of the paper ejection driven roller and the hardness of the paper ejection driven roller, and is given to the paper ejection driven roller in order to obtain an appropriate contact surface pressure. The load will also be different.

As described above, the contact surface pressure of the paper discharge driven roller varies depending on the conditions of the characteristics of the recording material, the characteristics of the ink, the contact surface width of the paper discharge driven roller, and the hardness of the paper discharge driven roller. . Therefore, the load applied to the paper ejection driven roller to urge the paper ejection driven roller to the paper ejection drive roller is determined from the correlation between the above conditions.

According to the second aspect of the present invention, in the ink jet type recording apparatus, the ink ejected to the recording surface of the recording material during drying is discharged to the discharge side. By applying a load to the discharge driven roller so that the contact surface pressure can be discharged without adhering to the driven roller, the operation and effect according to the first aspect of the present invention can be obtained.

According to a third aspect of the present invention, in the first or second aspect, the discharge driven roller mounting device is configured such that the discharge driven roller and the discharge driven roller are in surface contact with each other. The recording material is urged by a load determined from a correlation with the magnitude of the frictional resistance of the surface in contact with the recording surface so that the contact surface pressure can be discharged without causing slippage. And a discharge driven roller mounting device.

Although the surface of the ink in a semi-dry state is dry, the ink inside the ink is not yet dried in a liquid state, so that it is easily deformed or torn by a small force. Therefore, if a slip occurs between the dry surface of the semi-dry ink and the paper discharge driven roller, the ink surface may be damaged and the image quality may be degraded.

Thus, the paper driven roller having sufficient frictional resistance to prevent slippage is urged by a load that provides a contact surface pressure at which the paper can be discharged without causing slippage. The surface of the ink in the state is not deformed or broken.

Thus, according to the discharge driven roller mounting apparatus according to the third aspect of the present invention, in the ink jet type recording apparatus, in addition to the operation and effect of the first or second aspect of the present invention, the discharge type is provided. The effect of preventing the recording surface from being damaged by the paper driven roller sliding on the recording surface can be obtained.

[0026] The invention described in claim 4 of the present application provides claims 1 to
3. The paper ejection driven roller mounting device according to claim 3, wherein the paper ejection driven roller is a roller made of an elastic body.

As described above, since the paper discharge driven roller is a roller made of an elastic body, it is elastically deformed when urged by a predetermined load to the paper discharge drive roller, whereby the contact area on the nip surface is reduced. Become wider. Further, the hardness of the discharge driven roller can be set by the hardness of the member forming the elastic roller, and the frictional resistance of the surface of the discharge driven roller can be set by treating the surface thereof. Here, the roller made of the elastic body is not limited to a specific material, but includes a rubber roller having flexibility, particularly an elastomer.

According to the discharge driven roller mounting apparatus according to the fourth aspect of the present invention, in the ink jet type recording apparatus, depending on the type of the elastic roller member and the treatment of the surface thereof, the discharge driven roller can be driven. By setting the hardness and the frictional resistance of the surface, any one of claims 1 to 3 of the present application is set.
The effects and advantages of the invention described in the paragraph can be obtained.

According to a fifth aspect of the present invention, in the first aspect, the contact surface pressure is set to 6 gf / mm ² or less.
According to the ejected driven roller mounting device according to the invention of claim 5 of the present application, by setting the contact surface pressure to 6 gf / mm ² or less, various types of paper and ink used in normal printing can be used. With respect to the combination, the operation and effect of the invention described in claim 1 can be obtained with almost no problem.

The invention described in claim 6 of the present application provides
An ink jet recording apparatus provided with the sheet discharge driven roller mounting device according to any one of Items 5 to 5. According to the paper ejection driven roller mounting device according to the invention described in claim 6 of the present application, it is possible to obtain the operation and effect of the above-described invention according to any one of claims 1 to 5 in an ink jet recording apparatus. it can.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic plan view showing an embodiment of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side view thereof.

The recording apparatus 50 is provided with a carriage 61 which is supported by a carriage guide shaft 51 and moves in the main scanning direction X as recording means for performing recording on the recording paper P. On the carriage 61, a recording head 62 that performs recording by discharging ink onto the recording paper P is mounted. A platen 52 that defines a gap between the head surface of the recording head 62 and the recording paper P is provided to face the recording head 62. Then, the recording head 62 ejects ink onto the recording paper P while transporting the carriage 61 in the main scanning direction X, and intermittently transporting the recording paper P in the sub-scanning direction Y between the carriage 61 and the platen 52. The recording is performed on the recording paper P.

The paper feed tray 58 is configured to be capable of feeding recording paper P such as plain paper or photo paper, for example, and an ASF (auto sheet feeder) for automatically feeding the recording paper P is provided. Is provided. The ASF is an automatic paper feed mechanism having two paper feed rollers 57 provided on a paper feed tray and a separation pad (not shown). The paper feed roller 57 is
The rotation is controlled by a rotation driving force of a stepping motor or the like, and has a D-shaped outer shape in side view. One of the two paper feed rollers 57 is disposed on one side of the paper feed tray 58, and the other paper feed roller 57 is provided with a recording paper guide 59.
The recording paper guide 59 is attached to the recording paper P.
The paper tray 58 is provided so as to be slidable in the direction of the arrow indicated by the symbol A in accordance with the width of the paper tray. Then, due to the rotational driving force of the paper feed roller 57 and the frictional resistance of the separation pad, when the plurality of recording papers P placed on the paper feed tray 58 are fed, the plurality of recording papers P are fed at one time. The paper is fed automatically one sheet at a time without any need.

Then, the recording paper P automatically fed by the ASF is moved by a recording paper conveying means disposed downstream of the paper feed roller 57 in the sub-scanning direction Y, in the sub-scanning direction Y on the recording execution area side. The paper is intermittently conveyed toward the downstream side by a predetermined paper feed amount.

As a recording sheet conveying means for intermittently conveying the recording sheet P in the sub-scanning direction Y, a conveyance driving roller 53 and a conveyance driven roller 54 are provided. Transport drive roller 53
The recording paper P is transported in the sub-scanning direction Y by the rotation of the transport drive roller 53. A plurality of transport driven rollers 54 are provided, each of which is individually urged by the transport drive roller 53, and when the recording paper P is transported by the rotation of the transport drive roller 53, the recording paper P It rotates following the conveyance.

The paper feed roller 57 and the transport drive roller 5
3, a paper detector 63 according to a technique known in the prior art is provided. The paper detector 63 is provided with a self-returning habit of returning to a standing position, and has a lever pivotally supported so as to be able to rotate only in the recording paper transport direction into a transport path of the recording paper P. This is a detector having a configuration in which the lever is rotated by the tip of the lever being pressed against the recording paper P, whereby the recording paper P is detected. Paper detector 6
3 detects the start position and the end position of the recording paper P fed from the paper feed roller 57, determines a recording area in accordance with the detected positions, and executes recording.

On the other hand, a discharge drive roller 55 and a discharge driven roller 56 are provided as means for discharging the recorded recording paper P. The discharge drive roller 55 is rotationally controlled by a rotational driving force of a stepping motor or the like, and the recording paper P is discharged in the sub-scanning direction Y by the rotation of the discharge drive roller 55. The plurality of paper discharge driven rollers 56 are individually urged by the paper discharge drive roller 55, and when the recording paper P is discharged by the rotation of the paper discharge drive roller 55, the recording paper P comes into contact with the recording paper P and is Rotates following the paper ejection.

FIG. 3 is a perspective view showing a paper discharge driven roller 56 by the paper discharge driven roller mounting device according to the present invention. FIG. 4 is a view showing the discharge driven roller 56 shown in FIG.
FIG. 2 is a sectional view taken along line II.

The paper discharge driven roller 56 has a cylindrical shape and has a bearing portion 12 made of a resin member formed by injection molding.
And a roller section 11 made of a soft elastomer (rubber elastic body) member. A shaft hole 121 is provided in the center axis direction of the bearing portion 12. The rotating shaft 13 is inserted into the shaft hole 121, and the paper discharge driven roller 56 is rotatably supported by the rotating shaft 13. Discharge driven roller 56
Is driven by a biasing means (not shown).
5 is urged with a predetermined load.

The urging means includes, for example, a paper discharge driven roller 5
A predetermined load is applied to the paper discharge driven roller 56 by the spring force of the bar spring using a bar spring for the rotary shaft 13 that supports the shaft 6. Alternatively, it is possible to apply a predetermined load to the discharge driven roller 56 by the spring force of a coil spring. The present invention can be implemented with any urging means. Preferably, the variation in load is small, and the discharge driven roller 56
It is desirable that the load be applied evenly to the nip surface that comes into contact with the recording surface. And the recording paper P is
As shown, the paper ejection drive roller 55 and the paper ejection driven roller 56
And is discharged in the sub-scanning direction Y.

The paper discharge driven roller 56 rotates in contact with the recording surface of the recording paper P on which ink has been discharged from the recording head 62. The recording surface of the recording paper P from which the ink has been ejected is conveyed to a position in contact with the paper discharge driven roller 56 while the ink is being dried, that is, in a semi-dry state. This is because if the paper ejected after waiting for the ink ejected on the recording surface to completely dry is discharged, the printing execution throughput is extremely reduced due to the waiting time.

The ink on the recording surface in a semi-dry state has a dry surface, but the inside still remains liquid.
Therefore, the semi-dry ink is in an unstable state,
When a local force is applied, even a slight force easily deforms, and if it is dried while deformed, the image quality is deteriorated. Further, in some cases, the dry surface is torn and the liquid ink flows out, whereby the recording surface is stained and the image quality is deteriorated.

The paper discharge driven roller 56 is urged with a constant load against such a semi-dry ink surface, and rotates while being pressed against the recording paper P. Therefore, the urging force needs to be strong enough to press the recording paper P against the paper ejection drive roller 55 and must be strong enough not to damage the semi-dry ink surface.

FIG. 5 is a view showing a discharge driven roller 56 and a discharge drive roller 55 by the discharge driven roller mounting device according to the present invention.
5 is a side view showing a state in which the recording paper P is sandwiched and discharged between the recording paper P.

As described above, since the roller portion 11 of the paper discharge driven roller 56 is formed of a soft rubber member,
The paper discharge driven roller 56 is urged and pressed against the paper discharge drive roller 55, and comes into contact with the recording surface of the recording paper P in a crushed and deformed state as shown in the figure. As a result, the area of the nip surface is increased, and the discharge drive roller 5
5 is in contact with the recording paper P over a wide area, so that the recording paper P can be reliably discharged.

Here, the maximum allowable value of the contact surface pressure per unit area in the nip surface where the recording paper P can be discharged without damaging the semi-dry ink surface as the paper discharge driven roller is smoothly driven and rotated. Is the maximum allowable contact surface pressure α (gf / mm ² )
Then, the maximum allowable contact surface pressure α is expressed by the following equation (1).

The load (gf) applied to the paper discharge driven roller / the contact area of the nip surface (mm ² ) <α (gf / mm ² ) (1) The maximum allowable contact surface pressure α is the surface pressure of the recording paper P. The value varies depending on the ink absorption rate and the drying characteristics of the ink, and is a value obtained by an experiment or the like. FIG. 6 shows the maximum allowable contact surface pressure α and the time (the allowable arrival time (sec) until the portion of the recording paper P where the ink is ejected on the recording surface reaches the nip surface of the discharge driven roller 56. 3 is a graph showing the relationship between the graphs. 6, a graph A corresponds to a roller hardness of the roller portion 11 of the discharge driven roller 56 of 40 °, a graph B corresponds to a roller hardness of 50 °, and a graph C corresponds to a roller hardness of 70 °. The value of the load applied to the discharge driven roller at that time is described at the position of each point where the measured values of the graphs A, B, and C are plotted. The value obtained by dividing the load value by the contact area of the nip surface at that time is the surface pressure at that time.

From this graph, when the time required to reach the nip surface of the roller portion 11 of the discharge driven roller 56 is shortened, the surface pressure α of the cylindrical discharge driven roller 56 is correspondingly reduced. It can be understood that by reducing the size, there is an area where the paper can be discharged without damaging the semi-dry ink surface. For example, when a roller hardness of 40 ° or a roller hardness of 50 ° is used as the roller unit 11, even if the time required to reach the nip surface of the discharge driven roller 56 is set to 2 seconds, the surface pressure is about 6 gf / If it is set to about mm ² or less, it is possible to discharge the paper without damaging the semi-dry ink surface.

FIG. 6 shows different graphs A, B, and C depending on the difference in roller hardness. This is because, when the load is the same, a roller having a low hardness (soft) is more easily deformed than a roller having a high hardness, so that the contact area of the nip surface becomes large, and as a result, the roller having a low hardness is used. This is because the surface pressure becomes smaller. That is, it can be said that the maximum allowable contact surface pressure varies depending on the magnitude of the roller hardness used. From a different point of view, this indicates that a roller having a lower hardness can set a larger load to set the same surface pressure. For example, for a roller having a roller hardness of 40 °, the load is 50 g, the surface pressure is about 6 gf / mm ² , and the roller hardness is 50 °.
The roller has a load of 30 g and a surface pressure of 6 gf / mm.
It is about ² .

Next, the minimum value of the total load required for the discharge driven roller to be smoothly driven and rotated to reliably discharge the recording paper P is defined as the total load β (gf). 56
Is n, the total load β is expressed by the following equation (2).

Load (gf) · n> Total Load β (g) Applied to Discharge Driven Roller (2) The total load β is the frictional resistance of the recording surface of the recording paper P and the surface resistance of the roller 11. It depends on the frictional resistance value and is a value obtained by experiments and the like. In this way, by providing the required number of discharge driven rollers 56 so that the total load applied to each of the plurality of discharge driven rollers 56 is greater than the total load β, The recording paper P can be reliably discharged without causing damage to the semi-dry ink surface of the recording surface by being smoothly driven and rotated.

FIG. 7 shows the maximum allowable load on one discharge driven roller 56 and the time required for the portion of the recording paper P on which the ink is discharged to the recording surface to reach the nip surface of the discharge driven roller 56. 3 is a graph showing the relationship of The drawing shows a discharge driven roller 56 having the same hardness applied to the surface of the roller portion 11, a discharge driven roller 56 having no coating applied to the surface of the roller portion 11, and a conventional toothed roller ( And a paper discharge driven roller having a knurled roller 21 (see FIG. 8). The driven paper discharge roller 56 having the surface of the roller unit 11 coated has a lower surface frictional resistance than the driven paper discharge roller 56 not having the surface of the roller unit 11 coated. The area on the line of each graph and the area below and to the right of the line are areas satisfying the paper discharge conditions.

As shown in FIG. 7, the paper discharge driven roller 56 (the roller having a low surface friction resistance) in which the surface of the roller portion 11 is coated is a paper discharge driven roller 56 in which the surface of the roller portion 11 is not coated. It can be seen that the maximum allowable load is smaller than that of the roller having a high surface friction resistance. The reason is that, when the magnitude of the load applied to the roller portion 11 increases, the driven rotation resistance (the difficulty of the driven rotation) of the discharge driven roller 56 increases by that much, and the roller having low surface friction resistance is This is considered to be because the roller is more slippery than the roller having the higher surface frictional resistance between the recording paper and the recording paper. FIG. 6 described above shows a relationship that is satisfied when the paper discharge driven roller 56 is smoothly driven and rotated.
If slippage occurs between the roller surface and the recording paper even at the same surface pressure, the semi-dry ink surface will be damaged. Therefore, it can be understood that even if the rollers have the same hardness, a roller having a lower surface friction resistance cannot apply a larger load as a roller having a higher surface friction resistance from the viewpoint of slip prevention.

FIG. 7 shows a conventional paper driven driven roller having a serrated roller for keeping the trace of the tooth tip attached to the recording surface of the recording paper P at an acceptable level so as not to cause any problem visually. As such, its maximum allowable load is reduced. Therefore, as shown in the above equation (2), in order to obtain a total load larger than the total load β, it is necessary to arrange a large number of paper discharge driven toothed rollers. On the other hand, the discharge driven roller 56 according to the present invention has a large contact area because it comes into surface contact with the recording paper, and as shown in FIG. Since the allowable load can be increased, it is possible to reduce the number of discharge driven rollers 56 for obtaining a total load larger than the total load β.

Conventionally, the toothed roller 21 (FIG. 8) is in contact with the recording surface of the recording paper P between the paper discharge driven roller 56 and the recording execution area by the recording head 62 to discharge the recording paper P. , And the recording paper P is arranged so as to reversely warp. The toothed roller 21 is provided for one purpose to prevent a cockling phenomenon,
By causing the recording paper P to be warped in reverse, the recording paper P is pressed against the platen 52 from the recording surface side so that the recording paper P does not float. Here, the cockling phenomenon is a phenomenon in which the recording paper P is wavy deformed and stretched by being wetted with the ink, whereby the recording paper P rises from the platen 52.

In the embodiment according to the present invention, as shown in FIG. 5, the paper discharge driven roller 56 is pressed against the paper discharge drive roller 55.
1 is crushed and deformed along the outer peripheral surface of the paper discharge drive roller 55. Then, the recording paper P is reversely warped along the outer peripheral surface of the discharge drive roller 55 on the nip surface, so that the recording paper P is pressed against the platen 52. This makes it possible to reversely warp the recording paper P without separately providing a toothed roller 21 for reversely warping the recording paper P. The present invention can be implemented even if the toothed roller 21 is provided and the recording paper P is reversely warped as in the conventional case.

As described above, according to the paper ejection driven roller mounting apparatus according to the present invention shown in the above embodiment, the paper ejection driven roller 56 has a cylindrical shape and comes into surface contact with the recording surface. Therefore, no force is locally applied to the semi-dry recording surface during drying, and there is no possibility that the recording surface during drying is locally deformed. Further, since the contact surface pressure of the paper discharge driven roller 56 on the nip surface is set to a height at which the ink during drying can be discharged without adhering to the paper discharge driven roller 56, the paper discharge driven roller 56 The attached ink does not stain the recording surface.

Further, it is possible to reduce the number of driven paper discharge rollers 56 and to eliminate the need for the conventional toothed roller 21 that reversely warps the recording paper P. Things.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. Needless to say,

[0060]

According to the present invention, it is possible to provide an ejecting driven roller mounting apparatus which is less likely to impair high quality recording in an ink jet recording apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an embodiment of an ink jet recording apparatus according to the present invention.

FIG. 2 is a schematic side view showing an embodiment of the ink jet recording apparatus according to the present invention.

FIG. 3 is a perspective view showing a paper ejection driven roller by the paper ejection driven roller mounting device according to the present invention.

FIG. 4 is a sectional view taken along line II of the sheet discharge driven roller shown in FIG. 3;

FIG. 5 is a side view showing a state in which recording paper is sandwiched and discharged between a discharge driven roller and a discharge driving roller by the discharge driven roller mounting device according to the present invention.

FIG. 6 shows a relationship between a maximum allowable contact surface pressure α and a time (permissible arrival time) until a portion where ink is ejected on the recording surface of the recording paper reaches a nip surface of a discharge driven roller. It is a graph.

FIG. 7 shows the maximum allowable load per discharge driven roller,
6 is a graph showing a relationship between a time at which a portion of the recording paper where ink is ejected on a recording surface reaches a nip surface of a discharge driven roller.

FIG. 8 is a perspective view showing a paper discharge roller by a conventional paper discharge driven roller using a toothed roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Roller part 12 Bearing part 13 Rotating shaft 50 Recording device 51 Carriage guide shaft 52 Platen 55 Discharge drive roller 56 Discharge driven roller 63 Paper detector 121 Shaft hole P Recording paper

Claims (6)

[Claims] An ink is ejected from a recording head reciprocating in a main scanning direction onto a recording material, and the recording material is intermittently conveyed in a sub scanning direction to perform recording. A discharge drive roller that is rotated and controlled in contact with the surface opposite to the recording surface; and a recording drive that is urged by the discharge drive roller and contacts the recording surface of the recording material while the ink is drying. A discharge driven roller mounting device of an ink jet type recording apparatus in which the recording material is discharged by a discharge roller constituted by a discharge driven roller rotatably supported by the discharge of the material. The discharge driven roller has a cylindrical shape in surface contact with the recording surface of the recording material, and a contact surface pressure of a nip surface in which the discharge driven roller and the recording surface of the recording material are in surface contact is The recording head extends from the recording head to the nip surface of the paper discharge roller. It is determined from the time required for the material to be conveyed, and is set to a height at which the ink ejected to the recording surface of the recording material during drying can be discharged without adhering to the discharge driven roller. And a sheet discharging driven roller mounting device. 2. The discharge driven roller mounting device according to claim 1, wherein the discharge driven roller mounting device is configured to adjust the characteristics of the recording material, the characteristics of the ink, and the width of the contact surface of the discharge driven roller so that the contact surface pressure is obtained. A discharge driven roller mounting device, which is urged by a load determined from a correlation with the hardness of the discharge driven roller. 3. The paper ejection driven roller mounting device according to claim 1, wherein a slip occurs between the paper ejection driven roller and a recording surface of the recording paper with which the paper ejection driven roller comes into surface contact. The recording medium is urged by a load determined from a correlation with the magnitude of frictional resistance of the surface of the recording material in contact with the recording surface so that the contact surface pressure can be discharged without causing any paper discharge. Paper driven roller mounting device. 4. The method according to claim 1, wherein
The paper ejection driven roller is a roller made of an elastic body,
An output driven roller mounting device characterized in that: 5. The method according to claim 1, wherein the contact surface pressure is 6
gf / mm ² or less. 6. An ink jet recording apparatus comprising the paper discharge driven roller mounting device according to claim 1.