JPH0369314B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention performs printing while maintaining a constant distance between the print head and the print medium by positioning the print head to follow changes in the thickness of the print medium. Regarding the printing mechanism.

(Prior Art) In an impact type serial printer that prints on various print media of different thicknesses, the distance between the print head and the print medium must be kept constant in order to print with uniform density. For this reason, conventionally, as disclosed in Japanese Patent Publication No. 51-33459, a print head is mounted on a carriage so as to be movable in a direction perpendicular to the spacing direction, and the print head slides while being pressed against the print medium. The printhead is integrally equipped with a pressing sliding member (hereinafter referred to as media follow) that moves the print head to a position where the distance between the print head and the print medium is kept constant even if the thickness of the print medium varies. ing.

By the way, the printing head strikes the printing medium by protruding a wire or pin through the ink ribbon,
In the so-called dot type, in which characters are printed using a collection of dots, the distance between the print head and the print medium is narrow due to the movement stroke of the wire or the like. Conventionally, since the ink ribbon passes through this narrow space, a ribbon protector is provided in front of the print head to prevent the printing medium from being contaminated with ink.
As disclosed in Japanese Patent No. 50-53123, the ink ribbon is guided away from the print medium on both sides of the print head.

In the printing mechanism having the print head position adjustment function as described above, a guide means for guiding the ink ribbon as described above is provided on a stand or frame that integrally supports the print head and the media follow.

(Problem to be Solved by the Invention) Conventionally, when replacing the ink ribbon in such a printing mechanism, first move the ribbon protector to widen the space in front of the print head, remove the old ink ribbon, and then replace the new ink ribbon. The ink ribbon is slightly slackened and stretched so as to pass through the ribbon guide means and the front of the print head. At this time, the path that the ink ribbon takes changes its direction at the ribbon guide means and in front of the printing head, so the ribbon tensioning described above must be done manually, and it must be done in places where hands are stained with ink or where it is difficult to reach. There were problems such as the work was cumbersome and time consuming.

The present invention is intended to solve the above-mentioned problems, and makes it possible to easily replace ink ribbons without getting your hands dirty.

(Means for Solving the Problems) The present invention provides a ribbon guide means for guiding an ink ribbon near the print head in a print mechanism in which a print head and a media follow are movably mounted in a direction perpendicular to the print medium. The ribbon guide post is supported on the same frame as the media follow, the print head and the media follow are separated and independent from each other, the print head is provided movably in a direction away from the media follow, and the print head is supported. The frame has locking means that engages with a member on the carriage to hold the print head in a predetermined position separated from the media follow when the ink ribbon is installed or removed. They are connected by forcing means so that they move integrally at the top.

(Function) In the present invention, the print head and the media follow are separated and independent from each other, the ribbon guide post is supported by the frame on the media follow side, and the print head can move in a direction away from the media follow. When replacing the ink ribbon, a large space can be created between the ribbon guide post and the printing head, and by securing this space with the locking means, the ink ribbon storage area can be replaced without directly touching the ink ribbon. By holding it, you can easily replace it. On the other hand, during printing, the locking means is released;
The print head and media follow are forcibly connected, and both move together to a position on the carriage that corresponds to the thickness of the print medium, so that uniform print quality can be obtained regardless of the thickness of the print medium. Make it.

(Embodiment) FIG. 1 is a simplified plan view showing essential parts of an embodiment of the present invention, and FIG. 2 is a similarly simplified side view.

In FIGS. 1 and 2, 1 is a print head supported by a head mount plate 2, 3 is a carriage frame that is separate and independent from the print head 1, and 4 is a print head located in front of the carriage frame 3. A media follower is fixed on the protruding base part 3a and slides on the surface of the printing medium while contacting it during printing; 5 is a ribbon guide post planted on the base part 3a of the carriage; 6 is a support part 7
A ribbon guide 9 is attached to the ribbon switching lever 8, which rotates around the ribbon, and positions the ink ribbon of the selected color at the tip of the print head. A guide shaft penetrating the head mount plate 10 in a slidable manner
and the post 11 on the carriage frame 3, 12 is a pull-up lever fixed to the head mount plate 2, and 14 is a pull-up lever that moves the head mount plate 2 and the carriage frame 3 in the vertical direction by the shaft 15. The base frame 16 is slidably supported on the post 17.
18 is a reset spring for returning the lock bracket 16 to its original position; 19 is a hold bracket that holds the lock bracket 16 integrally with the head mount plate 2; 20 is a lock bracket for the lock bracket 16; A limiter 21 provided on the hold bracket 19 for regulating the rotational position is an ink ribbon.

FIG. 3 shows the printing mechanism in a printing state. In the printing state, the carriage frame 3 is lowered by a head up-down mechanism (not shown) powered by a motor or a solenoid, and the media follower 4 is moved to the print medium 22. Apply contact pressure. Since the printing head 1 has a head mount plate 2 and a carriage frame 3 connected to each other via a spring 10, it is normally drawn until the head mount plate 2 comes into contact with the upper surface of the carriage frame 3. As the carriage frame 3 descends, the media follower 4 comes into contact with the print medium 22 and the carriage frame 3 stops, being positioned at a position with an appropriate distance between it and the print medium 22. . In this printing state, the pair of ribbon guide posts 5 on the carriage frame 3 are located further back than the tip of the print head 1, and the ink ribbon 21 is placed on the print medium 2 on both sides of the print head as shown in FIG.
They are being guided to stay away from 2.

Next, when the ink ribbon 21 reaches the end of its life and is to be replaced with a new ink ribbon, the pull-up lever 12 is held in the hand and pulled upward. This pull-up lever 12 is fixed integrally with the head mount plate 2, and the print head 1 and carriage frame 3 are separate and independent from each other.
By pulling up the pull-up lever 12, only the print head 1 moves upward against the tensile force of the spring 10. This movement of the print head 1 is linear due to the guide shaft 9 on the head mount plate 2 slidingly passing through the carriage frame 3. While the print head 1 is being pulled upwards, the lock bracket 1 that is integrated with it
One side of the base frame 14 comes into contact with a locking portion 14a formed by bending and extending a part of the base frame 14 at a right angle, but since this side is oblique, it rotates clockwise and escapes. When the lock bracket 16 passes the locking portion 14a of the base frame 14, it is rotated counterclockwise by the reset spring 18 to the position where it is regulated by the limiter 20, and even if the pull-up lever 12 is released, the lock bracket 1 remains in place.
6 is locked to this locking portion 14a, the printing head 1 is locked in a position separated from the media follower 4 and ribbon guide post 5 on the carriage frame 3, as shown in FIGS. 1 and 2. .

In this state, the ribbon guide post 5 is located further below the tip of the print head 1, and there is a wide gap between the two, so the ink ribbon storage section such as the ink ribbon cassette can be removed without directly touching the ink ribbon. You can easily take out the old ink ribbon from the printing mechanism by just doing this. Also, when setting a new ink ribbon, the ink ribbon can be easily inserted between the print head 1 and the ribbon guide post 5 from above as shown in Figure 1 while keeping the ink ribbon stretched in a straight line. There is no need to touch it.

After replacing the ink ribbon as described above, move the lock bracket 16 to the arrow A shown in FIG.
direction and rotate clockwise to release the engagement with the locking portion 14a of the base frame 14. By this operation, the print head 1 is lowered by the spring 10 until its head mount plate 2 touches the upper end surface of the carriage frame 3, and on the way, the ink ribbon 21 is hooked to the ribbon guide 6 at the tip of the print head 1, and the ink ribbon 21 is hooked to the ribbon guide 6 at the tip of the print head 1. Positioned as shown in the figure.

FIGS. 4 and 5 show another embodiment of the present invention, in which the printing mechanism configured as described above is provided with means for improving printing quality.

In the above-mentioned printing mechanism, the printing head section and the media follow section are separated and independent, and both are pseudo-fixed by a spring. For this reason, the printing head 1 is likely to vibrate due to the reaction when a printing element such as a printing wire collides with the printing medium during printing. Especially when the printing speed is high,
Since the cycle of the printing operation becomes shorter, the next printing operation must be performed before the vibrations have subsided, which may cause irregularities in the printed characters.

Therefore, in this embodiment, a pair of lock levers 23 are provided for connecting and fixing the print head section and the media follow section. This lock lever 23 is fixedly supported by a shaft 24 rotatably supported by the pull-up lever 12, and the shaft 24 is always biased by a spring 25 so as to rotate counterclockwise in FIG. , whose distal end claw portion is biased to engage with the post 26. The post 26 is provided on a side frame 27 fixed to the carriage frame 3, and therefore the print head section and the media follow section 4 are connected to the carriage frame 3, the post 26, the lock lever 23, the shaft 24, and the pull. They are integrally connected via an up lever 12 and a head mount plate 2. Therefore, even if a force is applied to the print head 1 to lift it up due to the impact of printing while the print head 1 is performing a printing operation, the print head 1 is held in a position that is inseparable from the media follower 4, and the print head 1 can be printed at high speeds. Even when printing, no irregularities occur.

When the print head 1 is pulled upward to replace the ink ribbon, the lock lever 23 is flipped up in the direction of the arrow in FIG. 5 to release the connection between the print head section and the media follow section. When the ink ribbon is replaced and the print head is returned to its original position, the post 26 naturally engages with the lock lever 23 which is waiting at the position regulated by the limiter 27.

Note that the other configurations except for the connection structure between the printing head section and the media follow section are the same as those shown in FIGS. 1 to 3, and therefore, the explanation will be omitted.

Next, the color selection operation of the ink ribbon in the printing mechanism having the above configuration will be explained.

The ink ribbon 21 is connected to a pair of ribbon guide posts 5 and a ribbon switching lever 8 near the print head 1.
It is guided by a ribbon guide 6 attached to the ribbon, and is color-coded in the width direction so that two-color printing is possible. When switching the printing color from one color to the other, the ribbon switching lever 8 is operated by a power source (not shown) via a ring or the like. The operation of this ribbon switching lever 8 is
The position of the ribbon guide 6 at the tip thereof is shifted relative to the printing head 1, so that the desired color portion of the ink ribbon 21 faces the ink ribbon 21.

On the other hand, at this time, the ink ribbon 21 is moved to the ribbon guide post 5 provided on the media follow section side.
slide on the side of the This ribbon guide post 5
The side surface of is in the shape of a circular arc with the support portion 7 at the center. Therefore, if the shape of the ribbon guide post 5 is simply cylindrical, the sliding movement of the ink ribbon will not be parallel to the side surface of the ribbon guide post 5, which may cause the ink ribbon to twist or break. Since the ink ribbon 21 moves in parallel with the side surface of the ribbon guide post 5 in close contact with the side surface of the ribbon guide post 5, the printing color can be selected without causing any trouble to the ink ribbon.

(Effects of the Invention) As explained above, the present invention allows the print head section and the media follow section to be separated and independent from each other, provides the ribbon guide means in the media follow section, and provides a ribbon guide means in the direction in which the print head is separated from the media follow section. Since it is movable, a large space can be secured in front of the print head, and the ink ribbon can be easily attached and removed without touching the ink ribbon directly.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention;
FIG. 2 is a schematic side view, FIG. 3 is a schematic side view showing another operating state of the first, FIG. 4 is a schematic plan view showing another embodiment of the present invention, and FIG. 5 is a schematic side view. It is a diagram. 1... Print head, 3... Carriage frame, 4
...Media follow, 5...Ribbon guide post,
12...Pull-up lever, 16...Lock bracket, 21...Ink ribbon, 22...Printing medium, 23
…Lots Clever.

Claims (1)

[Claims] 1. In a printing mechanism in which a print head and a medium pressing sliding member are mounted movably in a direction perpendicular to the printing medium, a ribbon guide post for guiding an ink ribbon in the vicinity of the printing head is provided in a frame integrated with the medium pressing sliding member. 1. A printing mechanism, characterized in that the frame and the printing head are provided separately and independently from each other, and the printing head is provided movably in a direction away from the frame.