JPH09248945A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow simultaneous setting of the relative positions of a recording head, a sensor and a liner scale by bringing a butt member for maintaining the posture of a carriage in a direct contact with a linear scale. SOLUTION: Since a carriage 5 is mounted slidably on a guide rail 9 loads a recording head 4 on one side, it tends to rotate in the arrow A directions as the whole. In order to maintain the posture of the carriage 5, resisting the rotating tendency, the apparatus is provided such that a part of a sensor 6 comes in contact with a linear scale 7 attached to a sub rail 8 comprising a highly strong member so as to resist the rotating tendency. Accordingly, the relative relationship between the sensor 6 and the linear scale 7 can be maintained constant. As a result, it only needs to determine the height of the carriage 5 and the recording head 4 mounted thereon with a guide rail 9, and determine the tilt thereof with the sub rail 8. Therefore, it is not necessary to adjust the relative positions of the sensor 6 and the linear scale 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a plotter or a printer for ejecting ink from a recording head to print or form an image on a recording material such as paper according to an image signal.

[Prior art]

In the well-known image forming apparatus as described above, a long plate-like linear scale provided with a large number of fine lines extending in a direction orthogonal to the running direction of the recording head is provided in parallel with the running direction of the recording head. It has been proposed that a fine line is read by a sensor provided on a carriage carrying a recording head to control the timing of ink ejection.

[0003]

By the way, in this type of apparatus, whether or not the distance from the ink ejection port to the recording material can be maintained at a predetermined value has a great influence on the image quality. Must be finely adjusted, and the position and orientation of the carriage on which this is mounted is also adjusted, and the position of the sensor arranged on this also naturally shifts.

For this reason, since it becomes impossible to read the linear scale by the sensor, it becomes necessary to adjust the linear scale this time. However, the linear scale is a long print that covers almost the entire width of the maximum printable recording material. Since it is a member of No. 2, it is not easy to adjust, and it is not preferable that the adjustment is performed again by adjusting other members because the assembly efficiency is significantly lowered and the cost is affected.

The present invention has been made to cope with such a situation, and in the image forming apparatus as described above, a carriage arranged on a rail member for guiding traveling and a recording head mounted on the carriage. Another object of the present invention is to provide an image forming apparatus which is capable of setting relative positions of a sensor and a linear scale at the same time, and which is excellent in assembly accuracy and workability.

[0006]

Configuration of the Invention

In order to achieve the above object, the present invention is reciprocally supported by a columnar guide rail provided in a direction orthogonal to the recording material conveying direction to form an image. In an image forming apparatus that determines a print timing by reading a linear scale extending in the carriage traveling direction by a carriage equipped with a recording head for performing printing and a sensor arranged on the carriage, the linear sensor is provided in the sensor or in the vicinity thereof. An image forming apparatus (1) characterized by comprising a rotation restricting means for coming into contact with a scale to prevent the carriage from rotating, or in the above-mentioned (1), the rotation restricting means is a sensor. In the image forming apparatus (2) or the above-mentioned (1), the rotation restricting means has a convex portion formed on the carriage. An image forming apparatus (3) comprising a linear scale and an elastic material for elastically biasing the convex portion, or in the above (1), the rotation restricting means is provided on the carriage side. The image forming apparatus (4) is a rotating member that is abutted against the linear scale.

With such a configuration, in an image forming apparatus that ejects ink to form an image, the configuration of the mutual relationship between the recording head, the sensor, and the linear scale becomes easy, and the workability of assembly and adjustment is remarkable. Improve to.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view schematically showing only a recording material conveying portion and a printing portion of an image forming apparatus showing an embodiment of the present invention. The recording material 3 is nipped by the conveying roller 1 and the pinch roller 2 provided on the apparatus main body side and intermittently moves in the direction of the arrow X in the drawing.

A carriage 5 is arranged on a guide rail 9 extending in the width direction of the recording material 3, and moves along the guide rail 9 in the width direction of the recording material 3, that is, the arrow Y direction in the drawing. A recording head 4 and a sensor 6 are arranged on the carriage 5.

A linear scale 7 is arranged on the apparatus main body side in parallel with the traveling direction of the carriage 5, and the carriage 5
The sensor 6 disposed on the recording head 4 reads the scale of the linear scale as the vehicle travels, and the recording head 4 ejects ink onto the recording material 3 in response to the print signal to perform printing. When the printing of one line is completed, the recording material 3 moves in the direction of arrow X by a predetermined amount and the printing of the next line is performed.

FIG. 2 is a schematic side view of the carriage 5 mounted on the guide rail 9 in the direction of the arrow Y, which is formed of a transparent film on the sub-rail 8 arranged parallel to the guide rail 9. A linear scale 7 having a thin line in the direction parallel to the paper surface is attached over the entire length.

Since the carriage 5 is slidably mounted on the guide rail 9 and has the recording head mounted on one side as shown in the drawing, it has a tendency to rotate in the direction of arrow A as a whole.

In order to maintain the posture of the carriage 5 against this tendency, the sub-rail 8 is formed of a member having a high strength, and a part of the sensor 6 contacts the linear scale 7 attached to the sub-rail 8. It is constructed so as to come into contact with and face the above-mentioned rotational tendency.

Any appropriate sensor can be used as the sensor 6, but in the illustrated apparatus, the sensor 6 is a linear scale 7.
Are arranged so as to sandwich, and a light emitting part is provided on one side and a light receiving part is provided on the other side, and changes in the amount of light received by the light receiving part due to the beam passing through the thin line of the linear scale from the light emitting part are detected. It uses a photo interrupter.

Because of the above-mentioned structure, the sensor 6
Is in direct contact with the linear scale 7, the sensor 6
The linear relationship between the linear scale 7 and the linear scale 7 is maintained constant. Therefore, the carriage 5 and the recording head 4 mounted on the carriage 5 need only have their heights determined by the guide rails 9 and their inclinations determined by the sub-rails 8, and there is no need to adjust the relative positional relationship between the sensor 6 and the linear scale 7. Therefore, there is a remarkable effect in improving the assembly efficiency.

FIG. 3 is a side view of a carriage portion showing another embodiment similar to the apparatus of the above-mentioned embodiment, and corresponding portions are designated by the same reference numerals. In this apparatus, a convex portion 5a is formed on a portion of the carriage 5 that faces the linear scale 7, and a spring 12 is arranged on the side opposite to the convex portion 5a as viewed from the sub-rail 8 so that the linear scale 7 has the convex portion. 5a is abutted.

In this device, the sensor 6 has a linear scale 7
This is suitable when there is no room to be brought into contact with, and the accuracy can be improved by providing the convex portion 5a near the sensor 6. Further, since the sub-rail is sandwiched by the spring member at the positioning portion in the rotating direction, it is possible to well counteract external vibration and impact during printing.

FIG. 4 is a side view of a carriage portion showing another embodiment, in which parts corresponding to those of the above-mentioned devices are designated by the same reference numerals. In this apparatus, a rotatable roller 16 is provided at an upper portion of the carriage 5 pivotally supported by the guide rail 9 and at a portion facing the linear scale 7.

It is assumed that the linear scale 7 is not fixed to the sub-rail or the like, but only both ends thereof are fixed.
Further, a cylindrical sub-rail 17 is arranged on the side opposite to the rollers 16 with respect to the linear scale.

With such a structure, when the carriage 5 having a tendency to rotate in the counterclockwise direction in the drawing travels in the direction perpendicular to the paper surface, the rollers 16 provided on the carriage 5 are sub-rails 17 via the linear scale 7. Press the sensor 6
And the linear scale 7 are kept at a constant position.

According to this apparatus, since the linear scale is not fixed to the sub-rail or the like over the entire length, it is possible to use a cylindrical member having higher rigidity, which is effective for improving traveling accuracy. Further, since the abutting member for the linear scale is a roller, there is no possibility of damaging the linear scale.

[0022]

As described above, according to the present invention,
In an image forming apparatus equipped with a linear scale and a sensor for controlling image formation of a carriage that carries a recording head for forming an image, an abutting member for maintaining the attitude of the carriage is brought into direct contact with the linear scale. By doing so, the relative positions of the recording head, the sensor, and the linear scale can be set at the same time, so that the workability and accuracy of assembly and adjustment can be significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a main part of an image forming apparatus to which the present invention is applied.

FIG. 2 is a schematic side view of the above-mentioned carriage portion.

FIG. 3 is a schematic side view of a carriage portion according to another embodiment.

FIG. 4 is a schematic side view of a carriage portion showing still another embodiment.

[Explanation of symbols]

1 Conveyor Roller 7 Linear Scale 2 Pinch Roller 8, 17 Sub Rail 3 Recording Material 9 Guide Rail 4 Recording Head 12 Spring 5 Carriage 16 Roller 6 Sensor

Claims (4)

[Claims] 1. A carriage traveling direction supported by a carriage, which is reciprocally supported by a guide rail provided in a direction orthogonal to a recording material conveyance direction, and on which a recording head for forming an image is mounted, and a sensor arranged on the carriage. An image forming apparatus for reading a linear scale extended to a position to determine print timing, comprising: a rotation restricting unit that abuts on the sensor or the vicinity thereof to prevent the carriage from rotating by contacting the linear scale. A characteristic image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the rotation restricting means is the sensor. 3. The rotation restricting means comprises a convex portion formed on the carriage and an elastic material for elastically biasing the convex portion on a linear scale.
The image forming apparatus as described in the above. 4. The image forming apparatus according to claim 1, wherein the rotation restricting means is a rotating member which is provided on the carriage side and contacts the linear scale.