JPH0420610Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a head protection device for protecting a print head of, for example, an on-demand type inkjet printer.

[Background of the invention] In inkjet printers, especially on-demand type inkjet printers, it is necessary to protect the head by sealing the nozzle tip when not printing in order to prevent air from entering the nozzle tip and ink drying at the nozzle tip. .

FIG. 7 shows an example of such a sealed protection device. A carriage 20, which reciprocates along a guide shaft 22 extending along a printing line, is equipped with a printing head 21 having a plurality of nozzles (not shown). A cap 23 sealing the tip of the print head 21 is attached to the other end of the L-shaped arm 24 via a pin 26. The arm 24 is rotatably attached to a frame (not shown) via a pin 25.

When the carriage 20 moves to the home position, it pushes against one end of the arm 24. As a result, the arm 24 rotates about the pin 25, and the cap 23 moves downward in the figure to press against the head 21 and hermetically protect the head 21.

In this configuration, the moving direction of the carriage 20 and the reaction force acting on the carriage 20 are opposite, making it impossible to maintain a sufficiently large pressing force on the carriage 23. In some cases, the carriage 20 is pushed back by the reaction force, and the head capping is interrupted. There were problems such as incompleteness.

[Purpose of the invention] The purpose of the invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a capping device with a simple structure that can reliably seal and protect the print head at a low cost.

[Summary of the invention] In order to achieve the above object, the present invention provides an actuator in front of the waste ink tank, which has an inclined part slightly inclined with respect to the carriage running direction and a flat end part almost parallel to the carriage running direction. This is characterized in that the actuator is pushed by the end face of the cartridge to rotate the waste ink tank and press the cap against the printing head to protect it. The present invention will be explained below with reference to FIGS. 1 to 6 showing embodiments.

[Embodiment of the invention] A waste ink tank (hereinafter referred to as a tank) 2 is rotatably attached to a frame (not shown) via a support pin 3 and a support stand 1 provided on both side walls thereof.
An elastic cap 5 made of foamed resin such as felt is attached to the upper front surface of the tank 2. Further, on the lower front surface of the fulcrum pin 3, an actuator 4 having elasticity such as a plate spring is mounted.
is installed.

A print head 8 having a plurality of nozzles is mounted on a carriage 7 that reciprocates in the print line direction along a guide shaft 10, and a head cap 6 is provided at the tip of the print head 8. Said tank 2
A felt 9 for receiving ink ejected or flowing out from the nozzle via the felt 5 is housed inside, and is covered by a lid 11. As shown in detail in FIGS. 4 to 6, the actuator 4 is provided with an inclined portion 41 slightly inclined with respect to the guide shaft 10 and a flat end portion 42 parallel to the guide shaft 10.

Assuming that the center of gravity of the tank 2 is at position G shown in FIG. and stops the cap 5 at a position away from the head cap 6. FIG. 3 is a sectional view at a position where the carriage 7 is moved to the home position and the end surface of the carriage 7 completely rides on the actuator 4 (the positional relationship between the carriage 7 and the actuator 4 is shown in FIG. 6). In this state, the actuator 4 receives a compressive force and operates to rotate the tank 2 clockwise, so that the cap 5 is pressed against the head cap 6. That is, the front side of the print head 8 is hermetically protected.

In FIG. 3, the axis parallel to the front end surface of the carriage 7 is defined as the Y axis. From fulcrum pin 3 to cap 5
The length of the average distance to the center projected onto the Y axis is
Let L ₁ be the length obtained by projecting the average distance from the fulcrum pin 3 to the center of the actuator 4 onto the Y axis as L ₂ .
Further, if the forces acting on the actuator 4 and the cap 5 are respectively P ₂ and P ₁ , since the tank 2 is stopped in the state shown in FIG. 3, the rotational moments acting on the actuator 4 and the cap 5 are equal, and P ₁ The relationship L ₁ =P ₂ L ₂ holds true. Further, the force acting on the fulcrum pin 3 is P ₃ =P ₁ +P ₂ .

Now, if L ₂ /L ₁ = 2 or more, the force P ₂ is P ₁ /
2 or less, but the amount of rotational movement of the cap 5, that is, the stroke, becomes small, and if the stroke is small, the width of the cap 5 and the head cap 6 must be narrowed and the rotation angle must be increased. That is, since the cap 5 is slightly inclined downward to the right with respect to the guide shaft 10, if the stroke is small, the lower right end of the cap 5 will touch the carriage 7.
If the rotating angle is small, there is a risk that the ink discharged into the cap 5 will not fall into the tank 2 but will spill onto the carriage 7 side.

Conversely, if L ₂ /L ₁ = 1/2 or less, the force P ₃ acting on the fulcrum pin 3 becomes 3P ₁ or more, and the fulcrum pin 3
Abrasion and breakage become a problem.

When L ₁ =L ₂ , the force P ₃ acting on the fulcrum pin 3 is not so large as 2P ₁ , and the stroke of the cap 5 can also be made large.

4 to 6 show the positional relationship between the carriage 7 and the actuator 4. FIG. 4 shows the state before the carriage 7 makes contact. Figure 5 shows the carriage 7.
The end portion of the actuator 4 is in contact with the inclined portion 41 of the actuator 4. A force P _{4 acts on the actuator 4} in a direction perpendicular to the inclined portion 41 . Here, the angle formed by the guide shaft 10 and the force P ₄ is assumed to be θ ₁ . In order for the carriage 7 to get over the slope 41 from the position shown in FIG. 5, it must be pulled to the left in the figure with a force greater than P _4COS θ ₁ . However, as shown in Figure 6,
When the end of the carriage 7 passes over the slope 41, a force acts on the flat part 42 of the actuator 4.
The angle θ ₂ between P ₅ and the guide shaft 10 is 90 degrees, and the force parallel to the guide shaft 10 can be made zero.
That is, since there is no longer any force trying to return the carriage 7, the cap 5 is pressed against the head cap 6 with a predetermined force.

[Effects of the invention] According to the invention, the cap is pressed against the printing head as the carriage moves, and the force to return the carriage is eliminated when it is pressed, so that the printing head can be reliably protected. It becomes like this. Further, the force acting on the fulcrum pin can be reduced, and there is no need to worry about the fulcrum pin being worn out or broken.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the tank constituting the device of the present invention, Fig. 2 is a side view showing the relationship between the carriage and the tank, Fig. 3 is a sectional view showing the sealed protected state, and Fig. 4 6 is a cross-sectional plan view showing the positional relationship between the carriage and the actuator, and FIG. 7 is a plan view showing an example of a conventional device. In the figure, 1 is a support base, 2 is a waste ink tank, 3 is a fulcrum pin, 4 is an actuator, 41 is an inclined part, 42 is a flat end part, 5 is a cap, and 6 is a
1 is a head cap, 7 is a carriage, 8 is a print head, and 10 is a guide shaft.

Claims (1)

[Claims for Utility Model Registration] 1. A carriage equipped with a print head having at least one nozzle for ejecting ink particles is moved back and forth along a printing line, and in the process of this movement, ink particles are ejected from the print head. In an inkjet printer that prints, a waste ink tank is provided at the home position of the carriage and is rotatably supported around a fulcrum pin provided approximately at the center of the side wall of the waste ink tank, and an upper front surface of the waste ink tank. a cap that covers the nozzles of the print head; and a cap that is attached to the front surface of the waste ink tank with one end facing the carriage, and has an inclined part that is inclined with respect to the carriage running direction, and a cap that has an inclined part that is tilted with respect to the carriage running direction, and a cap that covers the nozzles of the print head; An actuator having parallel flat portions. 2. The head protection device for an inkjet printer according to claim 1, wherein the distance between the fulcrum pin and the center of the cap is approximately equal to the distance between the fulcrum pin and the actuator.