JP2000108438A - Image recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recording apparatus capable of forming an image of good quality by suppressing the positional shift of a recording medium in a lateral direction in an image forming area. SOLUTION: A recording medium feed means 10 holding a sheet-like recording medium P from both surfaces thereof to feed the same in a predetermined direction is provided and a recording head 42 ejecting ink to the surface of the recording medium P to form a desired image is provided on the downstream side of the feed means 10. A feed roller pair 2 rotating while holding the recording medium P from both surfaces thereof to feed the recording medium P is provided on the downstream side in a feed direction of the recording head 42 and a fixing roller fixing an image while pressing the recording medium P is provided on the downstream side of the feed roller pair 2. The feed roller pair 2 is arranged so that the plane Y containing the axial lines of the respective rollers 3 of the feed roller pair 2 crosses the feed direction of the recording medium P at a non-right angle. Since the recording medium P comes into surface contact with the rollers 3, large braking force suppressing the lateral positional shift of the recording medium P in an image forming area is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head for ejecting ink toward a recording medium to form an image on the recording medium, and a direction perpendicular to a feeding direction of the recording medium while pressing the recording medium. The present invention relates to an image recording apparatus provided with a fixing roller that rolls to fix ink adhered to a recording medium.

[0002]

2. Description of the Related Art An example of the above-described image recording apparatus is shown in FIGS. 3 is a perspective view showing a main part of the conventional image recording apparatus, and FIG. 4 is a side view in the direction of arrow F in FIG. 3, showing a schematic configuration of the conventional image recording apparatus. FIG.

As shown in FIGS. 3 and 4, the image recording apparatus 70 includes a main roller pair (first feed roller pair) that is sequentially arranged in the feed direction of a sheet P as a recording medium.
10, a transport roller (second feed roller pair) pair 20, a discharge roller pair (third feed roller pair) 30, and a main roller pair 10 and a transport roller pair 20;
Forming means 40 for forming an image on a sheet and a pair of conveying rollers 2
The image fixing device 50 is provided between the image forming roller 0 and the discharge roller pair 30 and fixes an image formed on the sheet P as main components. Hereinafter, details of each unit will be described.

The main roller pair 10 comprises a main roller 11 and a pinch roller 12 provided so as to contact each other. The main roller 11 is appropriately driven and rotated by a driving means (not shown), and rotates while pinching the paper P together with the pinch roller 12 which comes into contact with the main roller 11 to rotate the paper P to form the image forming means 40. (In the direction of arrow A). Note that the diameter of the main roller 11 is determined by the transport rollers 21 and
, And the feeding of the paper P is controlled by the main roller pair 10.

The transport roller pair 20 comprises two transport rollers 21 and 21 which are also provided so as to abut each other. One of the transport rollers 21 is appropriately driven and rotated by a driving unit (not shown), and is rotated.
The paper P rotates together with the other transport roller 21 in contact therewith while pinching the paper P, and feeds the paper P toward the image fixing unit 50. As shown in FIG. 4, the transport roller pair 20 is provided such that a plane X including the axis of the transport rollers 21 and 21 is substantially orthogonal to the transport direction of the paper P transported from the main roller pair 10. The feeding direction of the paper P before and after the transport roller pair 20, that is, on the upstream side and the downstream side is set to be the same direction. Each of the transport rollers 21 and 21 arranged in this manner is in a state of being substantially in line contact with the sheet P.

The discharge roller pair 30 is composed of a discharge roller 31 and a pinch roller 32 which are provided so as to abut each other. The discharge roller 31 is appropriately driven to rotate by driving means (not shown), and rotates while pinching the sheet P together with the pinch roller 32 which comes into contact with the discharge roller 31 to move the sheet P out of the machine. Discharge.

The image forming means 40 includes a guide bar 44 provided along the width direction of the sheet P (along arrow BC).
A recording unit 41 engaged with the guide bar 44 and movable in the directions indicated by arrows BC.
4, pulleys 45a, 45 provided near both ends, respectively.
5b, an endless drive belt 46 wound around the pulleys 45a and 45b, a drive motor 47 for driving the pulley 45b, and a length provided to face the recording unit 41 and to support the back surface of the paper P. And a platen 48 of a length. The recording unit 41 includes a recording head 42 that ejects ink toward the paper P and a tank 43 that stores ink. The recording unit 41 is fixed to the outer peripheral surface of the drive belt 46, is driven by a drive motor 47, reciprocates in the direction of arrow BC while ejecting ink from the recording head 42, and moves on the paper P. Form an image. As the ink, a hot melt ink which solidifies at room temperature and melts when heated, an ink which becomes liquid at room temperature, and the like are used.

The image fixing means 50 is provided on the back side of the sheet P along the width direction (the direction indicated by the arrow D-E), and has a long fixing base 56 for supporting the sheet P from the back side;
A fixing unit 51 provided so as to face the fixing base 56 with the sheet P interposed therebetween and pressing the sheet P from the front side;
And two guide bars 57, 57 which are provided along the width direction (directions indicated by arrows DE) on the front side of the fixing member 51 and support the fixing unit 51 so as to reciprocate in the directions indicated by arrows DE. Pulleys 58a and 58b provided near both ends of the guide bars 57 and 57, respectively.
Endless drive belt 59 wound around
b, and a fixing unit 51 fixed to the outer peripheral surface of the drive belt 59 is driven by the drive motor 60 to reciprocate in the direction of arrow D-E. .

The fixing units 51 are arranged side by side at predetermined intervals along the width direction of the paper P, and each of the fixing units 51 has four substantially U-shaped support grooves 52a, 52b, 52c, 5c.
Two support plates 52, 52 having 2d formed thereon, and two support shafts 53, 53 fitted into the support grooves 52a, 52d at both ends thereof and connecting the support plates 52, 52, respectively;
Similarly, the paper P is fitted into the support grooves 52b and 52c.
Fixing rollers 5 rotatably supported in the width direction of the fixing roller 5
The fixing unit 51 is driven by the driving motor 60, and includes coil springs 55, 55 attached to the support shafts 53, 53 and urging the fixing rollers 54, 54 toward the fixing base 56. It is arrow D-
By moving in the direction E, the fixing rollers 54, 54 roll on the sheet P in the same direction and press the sheet P.

According to the image recording apparatus 70 having the above configuration, first, the main roller pair 10, the transport roller pair 20, and the discharge roller pair 30 are each driven intermittently to move the sheet P in the direction indicated by the arrow A by a predetermined amount. Feed pitch by pitch.

In the image forming means 40, while the feeding of the paper P being pitch-fed is stopped, ink is ejected from the recording head 42 toward the paper P, and the recording head 42 is moved to the width of the paper P. To form an image on the paper P. On the other hand, in the image fixing unit 50, while the feeding of the sheet P is stopped, the fixing unit 51 is moved in the width direction of the sheet P to fix the fixing roller 5.
4, 54 are rolled in the same direction. As a result, the paper P is pressed by the fixing rollers 54, 54, and the ink attached on the paper P is fixed on the paper P.

As described above, while the main roller pair 10, the transport roller pair 20, and the discharge roller pair 30 are intermittently driven to feed the paper P at a pitch, the image forming means 40 and the image fixing means 50 are respectively stopped while the paper P is stopped. By driving, an image can be formed on the sheet P on the upstream side of the pair of conveying rollers 20, and the formed image can be fixed on the sheet P on the downstream side of the pair of conveying rollers 20. Then, the sheet P on which the image is recorded in this way is discharged outside the apparatus by the discharge roller pair 30.

[0013]

However, in the conventional image recording apparatus 70 described above, the transport roller pair 2
0, the paper P is disposed in such a state that the paper P is substantially in line contact with the paper P, so that the pressure of the paper P by the paper rollers P is not sufficient, and the fixing rollers 54, 54 are not provided. There is a problem that the sheet P is displaced in the width direction due to the acting force accompanying the rolling of the sheet P.

When the fixing unit 51 moves in the width direction of the sheet P, the fixing rollers 54, 54 are rotated about the axis by the frictional force between the sheet P and the fixing rollers 54, and roll on the sheet P. At this time, the fixing roller 5
4, 54 in the moving direction of the fixing unit 51.
Pressing force acts. If the conveying rollers 21 and 21 have a sufficient force to squeeze the sheet P, the acting force of the fixing rollers 54 and 54 will not be transmitted upstream from the conveying rollers 21 and 21. , 21 are not strong enough to pinch the paper P,
The acting force is transmitted from 1, 21 to the upstream, and the sheet P is displaced in the width direction with respect to the main roller pair 10.

As described above, if the sheet P is displaced upstream from the pair of conveying rollers 20, the image formed by the image forming means 40 becomes distorted, which is extremely problematic in quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to form a high quality image by suppressing the displacement of the recording medium in the width direction in the image forming area. It is an object of the present invention to provide an image recording apparatus capable of performing the above.

[0017]

Means for Solving the Problems and Effects There is provided a recording medium conveying means for pressing a sheet-shaped recording medium from the front and back and conveying the recording medium in a predetermined conveying direction. A recording head that is provided on the downstream side in the transport direction of the recording medium transport unit and that ejects ink to the surface of the recording medium to form a desired image; and a recording head that is provided on the downstream side in the transport direction of the recording head. A pair of transport rollers for transporting the recording medium by rotating while pressing the recording medium from the front and back, and provided on the downstream side in the transport direction of the pair of transport rollers, formed by the recording head while pressing the recording medium. A fixing roller for fixing the image to a recording medium, wherein a plane including an axis of each roller constituting the pair of conveying rollers is not perpendicular to the conveying direction. It is characterized in that it has configured to intersect.

According to the present invention, each of the rollers constituting the pair of conveying rollers intersects at right angles to the feeding direction of the recording medium upstream and downstream of the pair of conveying rollers. Since the rollers are provided, the recording medium is wound around a part of the outer periphery of each roller. That is, each roller constituting the transport roller pair is in contact with the recording medium by a surface instead of a line as in the related art.

As a result, a large static friction force is generated at the contact portion between the recording medium, which is pressed by the rollers and comes into contact with the recording medium with a predetermined contact force, as compared with the prior art. The force acts as a braking force that prevents the recording medium from moving in the width direction. Therefore, even if a force that moves the recording medium in the width direction acts on the recording medium by the fixing roller rolling in the width direction of the recording medium, the acting force is reduced by the braking force. Transmission to the upstream side of the transport roller pair can be suppressed. This makes it possible to feed the recording medium on the upstream side of the conveying roller pair to a normal one with a small displacement in the width direction of the recording medium, and to improve the image formed on the recording medium by the recording head without distortion. can do.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view showing a schematic configuration of an image recording apparatus according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of FIG.

As shown in FIG. 1, in the image recording apparatus 1 according to the present embodiment, instead of the transport roller pair 20 in the above-described conventional image recording apparatus 70, a transport roller pair 2 having the same configuration is used. The configuration is the same as that of the conventional image recording apparatus 70 in other respects. Therefore, the same components as those of the conventional image recording apparatus 70 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, the conveying roller pair 2 is provided with two conveying rollers 3 provided so as to contact each other.
And a plane Y including the axes of the transport rollers 3
Crosses the feed direction of the paper P at a non-perpendicular angle, that is,
The transport rollers 3, 3 are arranged so that the plane Y intersects the plane Z perpendicular to the feeding direction of the paper P at an angle θ (θ ≠ 0 °). The feed directions of the paper P on the upstream and downstream sides of the transport roller pair 2 are set to be the same as each other.

Each of the transport rollers 3, 3 arranged as described above
As shown in FIG. 2, the sheet P is wound around a part of the outer periphery of each of the transport rollers 3. That is,
Each of the transport rollers 3, 3 is in contact with the sheet P by a surface, not by a line as in the related art. For this reason, a large static friction force is generated at the contact portion between the paper P and the respective transport rollers 3, which come into contact with each other with a predetermined contact force, as compared with the related art. Acts as a braking force that prevents the movement of

Therefore, even if the fixing rollers 54, 54 roll in the width direction of the sheet P, and the force for moving the sheet P in the width direction acts on the sheet P, the braking force Accordingly, the transmission of the acting force to the upstream side of the pair of transport rollers 2 can be suppressed. Thus, the paper P on the upstream side of the transport roller pair 2 can be fed normally with little misalignment in the width direction, and an image formed on the paper P by the recording head 42 can be properly distorted without distortion. Things.

It should be noted that the angle θ in the present invention is not required to be 0, and it does not matter whether it is positive or negative. Therefore, FIG. 1 shows an example in which each of the transport rollers 3 and 3 is provided to be tilted to the left. However, the present invention is not limited to this, and the rollers may be provided to be tilted to the right. The greater the angle θ, the greater the braking force, and the greater the effect of suppressing the movement of the sheet P in the width direction. However, this angle θ is such that the required braking force is obtained and the sheet P It is sufficient that the feed does not cause any trouble, and this can be set as appropriate.

[0026]

EXAMPLE Using the image recording apparatus 1 according to the present embodiment, the conveying rollers 3 and 3 were set to have a diameter of 29.7 mm and the angle θ
Was varied, and the feeding unevenness of the paper P was measured. The results are shown in Table 1 below.

Incidentally, the feed unevenness refers to the amount of positional deviation of the formed image caused by the positional deviation of the paper P in the width direction. Specifically, after setting the angle θ to a predetermined angle, the paper P is fed by a predetermined pitch, and when the fixing unit 51 rides on the left end of the paper P, ink is ejected from the recording head 42 and the left end of the paper P A predetermined image (for example,
Points or straight lines). After that, the sheet P is further fed by a predetermined pitch, and when the fixing unit 51 rides on the left end of the sheet P, ink is ejected from the recording head 42 to form a predetermined image again on the left end of the sheet P. Then, these operations are repeated 40 times, and 40 predetermined images are formed on the left end of the sheet P. Next, the sheet P is further fed by a predetermined pitch, and the ink is ejected from the recording head 42 when the fixing unit 51 rides on the right end of the sheet P to form the predetermined image on the right end of the sheet P. Thereafter, the sheet P is further fed by a predetermined pitch, and when the fixing unit 51 rides on the right end of the sheet P, ink is ejected from the recording head 42 to form a predetermined image again on the right end of the sheet P. And
These operations are repeated 40 times to form 40 predetermined images on the right end of the sheet P. Thereafter, the width of a total of 80 images formed on the left end and the right end of the paper P is measured as a substantial paper feed amount, and a difference between the real paper feed amount and a theoretical reference paper feed amount at which an image is to be formed is calculated. The average of the calculated differences was defined as feeding unevenness.

[0028]

[Table 1]

From Table 1 above, by making the angle θ larger than 0 ° (Examples 1 to 4), the feeding unevenness of the paper P is reduced as compared with the case where the angle θ is set to 0 ° (Comparative Example 1). It can be seen that the larger the angle θ, the smaller the unevenness in the feeding of the paper P. Therefore, the larger the angle θ, the better the quality of the image can be formed.

Although the embodiments of the present invention have been described in detail, it is needless to say that specific embodiments of the present invention are not limited to these embodiments. For example, in the present embodiment, the paper P is provided so that the feeding direction of the paper P coincides with the upstream and downstream sides of the pair of transport rollers 2.
If the paper P is provided so as to be in surface contact with each of the sheets 3, it is not always necessary to make the feed direction of the paper P coincide between the upstream side and the downstream side.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of an image recording apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a pair of conveying rollers in FIG. 1 in an enlarged manner.

FIG. 3 is a perspective view showing a main part of a conventional image recording apparatus.

FIG. 4 is a side view in the direction of arrow F in FIG. 3, showing a schematic configuration of a conventional image recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image recording apparatus 2 Conveying roller pair 3 Conveying roller 10 Main roller pair 11 Main roller 12 Pinch roller 20 Conveying roller pair 21 Conveying roller 30 Discharge roller pair 31 Discharge roller 32 Pinch roller 40 Image forming means 41 Recording unit 42 Recording head 48 Platen Reference Signs List 50 image fixing means 51 fixing unit 54 fixing roller 56 fixing base 70 image recording device

Claims (1)

[Claims] A recording medium conveying means for nipping a sheet-shaped recording medium from the front and back to convey the recording medium in a predetermined conveying direction; and a recording medium conveying means provided downstream of the recording medium conveying means in the conveying direction. A recording head that forms a desired image by ejecting ink to the surface of the medium, and a transport that is provided downstream of the recording head in the transport direction and that transports the recording medium by rotating while pressing the recording medium from the front and back. An image recording apparatus comprising: a roller pair; and a fixing roller provided downstream of the transport roller pair in the transport direction and fixing the image formed by the recording head on the recording medium while pressing the recording medium. An image recording apparatus, wherein a plane including an axis of each roller constituting the pair of transport rollers intersects the transport direction at a non-perpendicular angle.