JP2000062166A - Writing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration in print quality even when an ink head is moved at a high speed. SOLUTION: The writing head for ejecting ink to a recording sheet comprises a body 20 and a hood 21. The body 20 is arranged to move freely in a specified direction and provided with a nozzle 23 for ejecting ink. The hood 21 is a member covering from the nozzle 23 to the vicinity of the surface of recording sheet arranged to move at least to the front side in the moving direction along with the body 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing head device,
In particular, the present invention relates to a drawing head device that ejects ink while moving with respect to recording paper.

[0002]

2. Description of the Related Art Ink jet printers are provided as devices for recording information such as characters on recording paper. This inkjet printer has an inkjet head (hereinafter, simply referred to as an ink head) that is provided so as to be movable in a direction orthogonal to the recording paper conveyance direction. The ink head is provided with a large number of nozzles along the conveyance direction of the recording paper, and printing is performed by ejecting ink from the nozzles onto the recording paper.

[0003]

The state of the ink ejected from the nozzles of the ink head will be described in detail with reference to FIG. As shown in FIG. 1, the ink ejected from the ink head H includes a main droplet M and the main droplet M.
Satellite droplets S appearing at the rear part of the. The satellite droplet S is elongated as shown in the figure, and is easily affected by the wind caused by the movement of the ink head H. Therefore, in consideration of the influence of the wind on the satellite droplets, the moving speed of the ink head is preferably low.

However, recently, it has been desired to increase the printing speed, and therefore the moving speed of the ink head tends to be increased. In such a situation, the satellite droplets are strongly affected by the wind, and as shown in FIG. 2A or 2B, the liquid point s of the satellite droplets is different from the liquid point m of the main droplets. It ’s shifted,
A normal liquid point as shown in FIG. 2 (c) cannot be formed. This causes deterioration of print quality.

An object of the present invention is to make it possible to suppress deterioration of print quality even when the moving speed of the drawing head is increased.

[0006]

A drawing head device according to a first aspect of the present invention is a device for ejecting ink onto a recording sheet and comprises a main body and a hood member. The main body is provided so as to be movable in a predetermined direction with respect to the recording paper, and has a nozzle for ejecting ink. The hood member is a member that is provided so as to be movable with the main body at least on the front side in the moving direction of the main body, and covers from the nozzle outlet to the vicinity of the surface of the recording paper.

In this apparatus, a hood member extending from the nozzle outlet to the vicinity of the surface of the recording paper is provided at least on the front side in the moving direction of the main body. Therefore, when the main body moves, the hood member receives wind and suppresses the influence of wind on the ink ejected from the nozzles. Therefore, the satellite droplets drop to almost the same position as the main droplets, normal droplets are formed, and deterioration of print quality can be prevented.

A drawing head device according to a second aspect is the drawing head device according to the first aspect, wherein the main body is formed in a rectangular parallelepiped shape. Further, the hood member is attached to each of the pair of side surfaces in the moving direction. Here, even when printing is performed by ejecting ink while the main body reciprocates, the ink ejected from the nozzles is unlikely to be affected by wind, and deterioration of print quality can be prevented.

A drawing head device according to a third aspect is the drawing head device according to the first or second aspect, wherein the hood member is a tubular member attached to an end of the main body on the side where the nozzle is formed,
It covers the entire circumference of the space between the nozzle outlet and the vicinity of the surface of the recording paper. Here, not only the front side in the moving direction but also the entire side including the side is covered by the hood member. Therefore, it is possible to prevent not only the wind from the moving direction at the time of moving the head but also the influence of the wind from the side entrainment,
The print quality can be further improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an ink jet printer 1 which employs a drawing head device according to an embodiment of the present invention. The inkjet printer 1 has a printer body 2 and legs 3 that support the printer body 2. The printer body 2 has a rectangular parallelepiped case 5 that is long in one direction. A transport roller 6 for transporting the recording paper and a guide rail 7 provided in parallel with the transport roller 6 are arranged inside the case 5. The transport roller 6 is driven by a drive unit (not shown) and transports the recording paper P (two-dot chain line in the figure) in the direction indicated by the arrow A.

Along the guide rail 7, the recording paper P
Head unit 1 in the direction of arrow B orthogonal to the transport direction of
0 is movably provided. As shown in FIG. 4, the head unit 10 accommodates four ink heads 11 having different ink colors. As shown in FIGS. 4 and 5, each ink head 11 has a main body 20 and a pair of hoods 21 fixed to the side surfaces of the main body 20.

The main body 20 of each ink head 11 is in the shape of a rectangular parallelepiped that is long in the vertical direction, a connector 22 is provided on the upper surface 20a, and a large number of nozzles 23 for ejecting ink are provided on the lower surface 20b. This many nozzles 23
Are arranged side by side in a direction orthogonal to the moving direction B of the head unit 10. Further, a tube 24 for supplying ink to the nozzles 23 is provided on the side surface 20c having a narrow width of the main body 20.

The pair of hoods 21 are fixed to both side surfaces 20d and 20e of the ink head 11 in the moving direction so as to face each other. And each hood 21
The tip of the ink head 1 is, as schematically shown in FIG.
1 is attached to the head unit 10 and extends to the vicinity of the surface of the recording paper P. In FIG. 6, W indicates the flow of wind when the ink head 11 is moved.

In the ink jet printer having such a structure, when printing is performed on the recording paper, the recording paper is conveyed in the direction A by the conveying roller 6, and the head unit 10 is arranged on the recording area along the guide rail 7. While moving in the B direction, ink is ejected from the ink head 11 onto the recording paper to perform printing. In this printing operation, the ink head 11 moves in the B direction, but a hood 21 is provided in front of the moving direction as shown in FIG. The hood 21 prevents wind from moving into the gap between the outlet of the nozzle 23 and the surface of the recording paper P. Therefore, the influence of the wind on the liquid droplets ejected from the nozzles 23, especially on the satellite liquid droplets, becomes very small, and the normal liquid point as shown in FIG. 2C is formed on the recording paper P. Therefore, deterioration of print quality can be prevented.

[Other Embodiments] In the above-described embodiment, the hoods are provided on both side surfaces of the ink head 11 in the moving direction. However, in a device of the type that ejects ink only when moving in one direction, the ink is ejected. The hood may be provided only in front of the moving direction. In addition, a hood may be provided around the entire circumference in order to prevent wind from being caught in the lateral direction. An example of this case is shown in FIG. In the example shown in FIG. 7, a rectangular tubular hood 30 is fitted and fixed to the tip portion of the main body 20 of the ink head 11. This hood 30
The leading end of the sheet extends to near the surface of the recording paper as in the above embodiment.

The hood 30 covers the entire circumference of the space between the nozzle outlet and the surface of the recording paper, and the ink ejected from the nozzle is less susceptible to the influence of wind. Therefore, the print quality is further improved.

[0017]

According to the present invention as described above, the ink ejected from the nozzles is less likely to be affected by the wind when the head is moved, and the deterioration of print quality can be suppressed.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a problem of the present invention.

FIG. 2 is a diagram for explaining a problem of the present invention, and is a diagram showing a liquid point due to ink ejected from a nozzle.

FIG. 3 is a schematic perspective view of an inkjet printer to which an embodiment of the present invention is applied.

FIG. 4 is a schematic perspective view of a head unit.

FIG. 5 is a perspective view of an ink head.

FIG. 6 is a schematic front view of an ink head.

FIG. 7 is a perspective view of an ink head according to another embodiment.

[Explanation of symbols]

11 ink head 20 body 21,30 hood 23 nozzles

Claims (3)

[Claims] 1. A drawing head device for ejecting ink onto a recording paper, the main body being movably provided in a predetermined direction with respect to the recording paper, and having a nozzle for ejecting ink, and at least the main body. A drawing head device provided with a hood member movably provided on the front side in the moving direction together with the main body and covering from the nozzle outlet to the vicinity of the surface of the recording paper. 2. The drawing head device according to claim 1, wherein the main body is formed in a rectangular parallelepiped shape, and the hood member is attached to each of a pair of side surfaces in the moving direction of the main body. 3. The hood member is a tubular member attached to the end of the main body where the nozzle is formed, and covers the entire circumference of the space between the nozzle outlet and the vicinity of the recording paper surface. The drawing head device according to claim 1 or 2.