JP2776138B2 - Printhead positioning mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning mechanism for mounting a printhead, which is a printing unit of a printing apparatus, on a carrier.

[0002]

2. Description of the Related Art Conventionally, the positioning of a print head or the like, which is a printing unit of a printing apparatus, is performed by press-fitting and fixing two guide pins on a mounting surface of a carrier on which the print head is mounted, as shown in FIG. On the side of the mounting surface 20 of the head 2 on the carrier, a guide round hole 21 having one side fitted with a guide pin is formed, and the other side fitted with the guide pin absorbs a pitch error between the guide pins. A guide slot 22 having the same width as the guide hole diameter is provided on the left and right of the center, the positioning is performed so that the mounting can be easily performed, and it is tightened and fixed with a screw or the like via a screw hole 23. Was.

[0003]

In a conventional print head and a positioning mechanism for a carrier on which the print head is mounted, it is necessary to machine a positioning guide pin and a guide hole to be fitted into the guide hole so that one of the guide holes is an elongated hole. The width of the elongated hole must be controlled to be the same as the diameter of the other guide holes, and must be finished with high precision by end milling or the like so as to be parallel to the center axis in the longitudinal direction.

[0004]

According to a first aspect of the present invention, there is provided a positioning mechanism for a print head in a printing unit of a printing apparatus, wherein the carrier is within an allowable error with respect to a predetermined pitch dimension. A first guide pin and a second guide pin having a columnar shape provided at pitches that fluctuate, wherein the print head is pierced at the predetermined pitch dimension and fitted with the first and second guide pins, respectively. First and second guide holes having a shape, wherein the first guide hole has a hole diameter that fits tightly with the outer diameter of the first guide pin, and the second guide hole has A hole diameter larger than the outer diameter of the second guide pin by at least the allowable error, and a half of the difference between the outer diameter and the hole diameter with respect to the center position of the second guide pin; It is provided by shifting the only center position.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention.
A guide pin 51 for positioning is press-fitted into each of the left and right head mounting portions 50 of the carrier 5 inserted through the guide shaft 8, and a fixing screw hole 53 for screw fixing is provided. The print head 1, which is a printing unit of the printing apparatus, has a mounting surface 10 for mounting on the head mounting portion 50 of the carrier 5. The mounting surface 10 has a guide hole A11 which has an inner diameter substantially equal to the outer diameter of the guide pin 51 and is used to set and position the carrier 5 by fitting with one of the guide pins 51, and two guides larger than the outer diameter. The other guide pin 51 has an inside diameter that absorbs the permissible difference in the pitch between the pins 51 (indicated by P in FIG. 1).
A guide hole B12 to be loosely fitted and two screw holes 13 through which screws for fixing to the fixing screw holes 53 of the carrier 5 are respectively provided. The center position of the guide hole B12 is deviated from the center position of the other guide pin 51 by the difference in radius, and the inner wall of each of the guide hole A11 and the guide hole B12 on the printing surface side is formed by the guide pin 51. A screw is screwed into the fixing screw hole 53 through the screw hole 13 so as to make contact with the print head 1, and the print head 1 is fixed to the carrier 5. When printing,
The operation of the carrier 5 is guided by the guide shaft 8, the print head 1 mounted on the carrier 5 is carried to a printing position, and printing is performed by the print head. The printing stress at the time of printing is received at portions where the inner surfaces of the guide holes A11 and B12 on the printing surface side are in contact with the guide pins 51, respectively.

[0007]

As described above, according to the present invention, when positioning a print head, which is a printing unit of a printing apparatus, and a carrier on which the print head is mounted and which performs a printing position indexing operation, the press-fitting and fixing are performed on the carrier. The guide pin set by the above method and the guide hole to be fitted into and fitted to the guide pin are set on the print head side mounting surface. By securing the printing stress at the position supported by the guide pin while maintaining the reference direction of each inner wall surface with the round hole, when drilling the guide hole, the processing work is easy and the accuracy control is easy. You.
Also, assembling work can be performed easily as in the case where a long guide hole is conventionally set.

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of the present invention.

FIG. 2 is a perspective view of a conventional print head.

[Explanation of symbols]

 1, 2 Print head 5 Carrier 8 Guide shaft 10, 20 Mounting surface to carrier 11 Guide hole A 12 Guide hole B 13, 23 Screw hole 21 Guide round hole 22 Guide long hole 50 Head mounting part 51 Guide pin 53 Fixing screw hole

Claims (1)

(57) [Claims] 1. A positioning mechanism for mounting a printhead on a carrier in a printing unit of a printing apparatus,
The carrier includes first and second cylindrical guide pins provided at a pitch dimension that fluctuates within a range of an allowable error with respect to a predetermined pitch dimension, and the print head is pierced at the predetermined pitch dimension, and First and second guide pins are respectively provided with circular first and second guide holes fitted to each other, and the first guide hole is provided with the first and second guide pins;
The second guide hole has a hole diameter that is at least larger than the outer diameter of the second guide pin by the tolerance and has a hole diameter that fits tightly with the outer diameter of the guide pin. A print head positioning mechanism, wherein the center position of the guide pin is shifted by half the difference between the outer diameter and the hole diameter with respect to the center position of the second guide pin.