JPS6364316B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print head protection device for an ink jet printing device.

Conventionally, especially in on-demand type inkjet printing devices, it is required to keep the distance between the ink jetting surface of the print head and the recording paper narrow and constant. If this distance is narrowed, there is a risk that if the paper lifts up on the platen, the ink jetting surface will come into contact with the paper during the moving operation for printing, damaging the print head. As a countermeasure against this problem, it is conceivable to provide a protective plate on the side of the ink ejection surface so as to project slightly beyond the surface. Incidentally, in an on-demand inkjet printing device, a cleaning roller is provided at the end of the reciprocating path of the print head in order to remove air bubbles in the ink ejection chamber and clean the ink ejection surface. The so-called purge technique involves moving the printing head to a position facing the roller, ejecting a relatively large amount of ink toward the roller, forming an ink column between the print head and the roller, and removing this ink column. It is known (Japanese Unexamined Patent Publication No. 150030/1983). Since the distance between the cleaning roller and the ink jetting surface of the print head is set to be narrower than the distance between the recording paper and the ink jetting surface described above, the print head provided with the protection plate is placed so as to face the cleaning roller. When the roller is moved, unless the protection plate is evacuated in advance, the protection plate may come into contact with the surface of the roller or the side surface of the roller, damaging the roller or the protection plate. Therefore, it is necessary for this protective plate to protrude reliably when it faces the platen, and to retract toward the print head when it moves to face the roller.

The present invention has been made in view of the above points, and provides a printing device for an inkjet type printing device in which a protective plate for pressing the recording paper is provided so as to be separated from the platen side so that the ink receiving member can be protected. The purpose is to obtain a head protection device.

The present invention is an inkjet type printing device in which a carriage for holding a printing head is provided so as to be movable back and forth along the platen, and when the printing head is facing the platen, the protective plate protrudes toward the platen and protects the recording paper. This prevents the ink from lifting up, ensuring accurate ink jetting distance and ensuring reliable printing.Also, the print head can be moved to face the ink receiving member provided on the side of the platen. Then, the protection plate escapes in a direction away from the platen by the separating member, thereby sufficiently protecting the protection plate itself and the ink receiving member.

A first embodiment of the present invention will be described based on FIGS. 1 to 6. First, a cylindrical platen 2 that guides the recording paper 1 is rotatably supported by a frame (not shown), and a paper presser roller supported by an arm 4 biased by a spring 3 is installed at the bottom of the platen 2. 5 is provided. Furthermore, two presser rollers 8 are provided above the front of the platen 2 and are movable in the axial direction on a support shaft 7 that is stretched between arms 6 that are biased by a spring.

Next, two guide shafts 9 and 10 are provided in parallel at the front lower part of the platen 2. A carriage 11 is provided on these guide shafts 9 and 10 so as to be able to reciprocate. This carriage 11 is fitted into the guide shaft 9 and the guide shaft 10
It is fitted with a horizontal groove. A printing head 12 is attached to such a carriage 11, and a nozzle surface 13 of this printing head 12 is spaced apart from the above-mentioned platen 2 by a predetermined distance. The carriage 11 also has a protective plate 14 formed of an elastic plate.
is provided. This protection plate 14 is approximately U-shaped, and its base is fixed to the carriage 11 and has elastic legs 15.
A protective surface 16 is provided at the tip of the nozzle surface 13 and protrudes in the direction of the platen 2 by a predetermined distance from the nozzle surface 13. These protective surfaces 16 are the nozzle surface 1
Located on both sides of 3.

A frame 17 is provided on the extension line of the platen 2, and this frame 17 has a shaft 18.
A worm wheel 19 and a roller 20 serving as an ink receiving member for cleaning are integrally and rotatably attached to the shaft 18.
A worm 22 driven by a motor 21 is engaged with the worm wheel 19 . The surface of the roller 20 projects further toward the front than the surface of the platen 2. Further, the frame 17 is provided with a square bar guide 23 that serves as a separating body. This square bar guide 23 has a plurality of ridge lines 2.
4 polygonal column part 25 and inclined part 2 located at the tip
6, and is fixed with screws 28 through vertically elongated holes 27 formed in the frame 17.

In such a configuration, the carriage 11 reciprocates only within the range of the platen 2 during normal printing operations. Therefore, the recording paper 1 is prevented from being lifted off the platen 2 by the protection plate 14, and as a result, the distance from the surface of the recording paper 1 to the nozzle surface 13 is kept constant. When printing is completed, the carriage 11 holding the print head 12 is moved to the left end, that is, beyond the platen 2. At this time, before the protection plate 14 reaches the position of the roller 20, the inclined portion 26 of the square bar guide 23 comes into contact with the protection plate 14, and along with this movement, the protection plate 14 is moved in a direction away from the platen 2. As a result, as shown in FIG.
4 and the roller 20 will be reliably maintained as dimension A. Therefore, the protection plate 14 does not hit or come into contact with the roller 20.

Before starting printing, the printing head 12 is operated while rotating the roller 20, but it is most preferable that a single ink droplet is held between the surface of the roller 20 and the nozzle surface 13, and there is a gap between the two. If the ink does not appear to be spread out, the amount of ejection is insufficient, and if it falls as ink droplets, the amount of ejection is too large.

Furthermore, if the screw 28 is loosened and the square bar guide 23 is rotated to position it, the distance between the roller 20 surface and the protection plate 14 will be A' as shown in FIG. 5, and the distance can be adjusted within the range of A to A'. is possible. This adjustment is necessary to correct errors in each part and to improve safety when assembling the device.

Next, a second embodiment of the present invention will be described based on FIGS. 7 to 12. The same parts as in the previous embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, first, a guide plate 31 as a separating body having a guide notch 30 whose left side is raised by an inclined part 29 from an introduction part to a base part is fixed to a fixedly provided frame 17. A holder 35 having three shafts 32, 33, and 34 is fixed to the carriage 11, and a detent gear 39 having a shaft portion 36 and teeth 37 and having an eccentric hole 38 is rotatably attached to the shaft 32. A pawl 40 that engages with the teeth 37 is rotatably attached to the shaft 33. The shaft 34 also has a pin 41 in the middle.
and a fitting leg 44 having a pin 43 at one end and fitting into the guide notch 30 at the other end.
An L-shaped swing lever 45 is rotatably attached. Further, an intermediate lever 46 is rotatably attached to the shaft portion 36 of the detent gear 39. This intermediate lever 46 has an inclined hole 4 into which the pin 41 and the pin 43 are fitted.
7 and 48 are formed.

In such a configuration, when the carriage 11 is moved largely to the left, the fitting leg 44 of the swing lever 45 fits into the guide notch 30 of the guide plate 31, causing the carriage 11 to rotate clockwise when viewed from the left. As a result, since the pin 43 is fitted into the inclined hole 48, the intermediate lever 46 is rotated counterclockwise, and since the pin 41 is fitted into the inclined hole 47, the protective plate 42 is rotated clockwise. This causes the platen to move in the direction away from the platen 2. Therefore, the protection plate 42 does not hit or come into contact with the roller 20.

Note that when the pawl 40 is removed from the tooth portion 37 and the detent gear 39 is turned to engage the pawl 40 again,
For example, as shown in FIGS. 10 and 11, there is a deviation of a dimension B on one side. As a result, the intermediate lever 4
6 will change, and the protection plate 42 will change.
The amount of retraction is adjusted. Therefore, the eccentric hole 38
A detent gear 39 having a diameter is recognized as a regulating body. In addition, the intermediate lever 46 and the swing lever 4
5 acts as a repellent.

A third embodiment of the present invention is shown in FIGS. 13 to 18.
This will be explained based on the diagram. First, a printing head 12 is attached to the center of the carriage 11, and the carriage 11 is provided with a holding frame 49 which is an enlarged front portion of the printing head 12. On one side of this holding frame 49 is a protective plate 50 that protrudes from the nozzle surface 13 of the print head 12.
It is bent into a calyx shape. Also,
A horizontal surface 51 is formed on the other side of the holding frame 49, and a protective surface 5 is formed on this horizontal surface 51 at a position symmetrical to the protective plate 50 with the nozzle surface 13 as the center.
A protective plate 53 provided with a protective plate 53 is rotatably attached to a support shaft 54, and a long elongated hole 55 is formed in the intermediate portion of the protective plate 53 along its longitudinal direction. Further, a support shaft 56 provided on the horizontal surface 51
A set arm 58 is provided with a claw 56 that fits into the elongated hole 55 and has a fork-shaped fitting notch 57, and is rotatably attached to the set arm 58 while being biased clockwise by a spring 59 when viewed from above. There is. An opening/closing lever 62 is rotatably attached to the support shaft 54 and has a circular drive arm portion 60 that fits into the fitting notch 57 of the set arm 58 and a protrusion 61 that projects upward.

A guide plate 63 serving as a separating body is fixed to the frame 17 on the roller 20 side. This guide plate 63 has a guide notch 65 with a curved portion 64 whose position changes toward the front as it goes leftward from the entrance portion.

In such a configuration, when the carriage 11 is moved largely to the left, the protrusion 61 moves into the guide notch 6.
5 and rotate the opening/closing lever 62 clockwise. This causes the set arm 58 to rotate counterclockwise and the protection plate 53 to rotate clockwise. As a result, the protective surface 52 moves in a direction away from the platen 2 and does not come into contact with the roller 20 even if it passes through the roller 20 portion. Therefore, the safety of the roller 20 and the protection plate 53 is ensured. In the stationary state, the print head 1
2 is now facing the roller 20. Therefore, when ink is ejected, if the ink droplets are held by the roller 20 surface and the nozzle surface 13, the ejection amount is appropriate, and if the ink droplets are not held between the two, the ink droplets are ejected. If the amount is insufficient and the ink droplets fall, the amount of ejection is too large. Therefore, the amount of ink ejected is checked to some extent before printing.

In use, the carriage 11 is moved to the right so that the print head 12 faces the platen 2, but at this time the protrusion 61 has come out of the guide notch 65, so the protective surface 52 protrudes and the other side Together with the protective plate 50, the recording paper 1 guided by the platen 2 is prevented from lifting up, thereby making it possible to print with good inkjet.

In particular, when an external force is applied to the protective plate 53 for some reason, the claw 5 that fits into the long hole 55
6, which is a force directed from the pawl 56 toward the support shaft 56 that supports the set arm 58, so the set arm 58 acts as a stopper.
The protection plate 53 is locked. Therefore, even if an external force acts on the protection plate 53, it will not escape.

As described above, the present invention reciprocates the printing head along the platen, and the carriage is provided with a protection plate to prevent the recording paper guided by the platen from lifting up. The frame is equipped with a separator that releases the protective plate when the ink reaches the ink receiving member.
Even if there is an ink receiving member that performs ink jetting, the protection plate does not come into contact with it, and it is possible to effectively prevent the recording paper from lifting up while smoothly conducting the ink jetting test.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a plan view showing the position of the print head with respect to the platen and the ink receiving member, and FIG. 4 5 is a vertical side view of the main part, FIG. 5 is a vertical side view during adjustment, FIG. 6 is a partially exploded perspective view, FIG. 7 is an exploded perspective view showing the second embodiment of the present invention, and FIG. The figure is a side view, FIG. 9 is a partially enlarged side view, FIGS. 10 and 11 are partial side views during adjustment, FIG. 12 is a side view of the positioning state, and FIG. 13 is a side view of the present invention. FIG. 14 is a plan view of the main parts, FIG. 15 is a plan view showing the relationship between the protection plate and the set lever, and FIG. 16 is a plan view when the protection plate is retracted. FIG. 17 is a plan view of the carriage in the middle of its movement to the left, and FIG. 18 is a plan view of the carriage when it has finished moving. 1... Recording paper, 2... Platen, 11... Carriage, 12... Print head, 14... Protective plate,
20...Roller (ink receiving member), 23... Square bar guide (separator), 31... Guide plate (separator),
42... Protective plate, 50... Protective plate, 53... Protective plate, 63... Guide plate (separator).

Claims (1)

[Claims] 1. In an inkjet type printing device in which a carriage for holding a print head is reciprocally provided along a platen that guides a recording paper, an inkjet printer is provided on a side of the platen with a carriage that is larger than the distance between the tip of the print head and the recording paper. An ink receiving member for cleaning, which is set to have a narrow distance from the tip of the printing head, is attached to the frame, and a protective plate is provided on the carriage, located at least on the ink receiving member side of the printing head, and protruding toward the platen. , the frame is provided with a separation body that directly or indirectly abuts the protection plate when the printing head moves along the platen toward the ink receiving member, and the separation body separates the protection plate from the ink receiving member. A print head protection device for an inkjet type printing device, characterized in that the print head is retracted in a direction away from the print head.