JPH043313B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a ribbon band switching device for a printer that prints by appropriately switching a printing ribbon having at least two or more types of ribbon bands in the width direction.

Prior Art As shown in Japanese Utility Model Application Publication No. 54-182010, for example, a conventional printer moves back and forth parallel to the axis of a platen, and its base end is rotatably supported on a carriage on which a print head is placed. a link arm having a guide plate whose tip end faces the printing line of the platen and stands vertically in a straight line;
The ribbon band switching device includes an eccentric camshaft that moves the link arm vertically by a predetermined amount of rotation, and at least one ribbon band switching device is provided, which is supported by a guide plate so as to be movable in the left and right directions as the link arm rotates. Among the printing ribbons having two types of printing ribbon bands in the width direction, by arranging the desired printing ribbon band to face the printing line of the platen, multicolor printing is made possible and printing ribbon consumption efficiency is improved. There is.

Printers that insert and eject print paper from above the platen are equipped with paper feed rollers above and below the print lines on the platen, or paper bails that press the print paper against the platen. When the above-mentioned ribbon band switching device is installed in a printer, the above-mentioned paper feed roller or paper bail needs to be placed at a location where it does not interfere with the vertically moving guide plate and therefore with the printing ribbon.

However, in the conventional ribbon band switching device described above, since the printing ribbon is supported linearly by the guide plate, the vertical movement distance of the guide plate is long, and the printing line of the platen and paper feed are It was necessary to set a long distance between the rollers and the paper bail.

For this reason, the unprintable area at the top and bottom of the printing paper becomes large, and it becomes difficult to press and hold the printing paper against the platen in the vicinity of the printing line on the platen, which makes it difficult to hold the printing paper during printing operations. The condition became unstable, leading to printing defects.

This invention was invented in order to solve the above-mentioned conventional drawbacks, and its purpose is to reduce the unprintable area at the top and bottom of the printing paper and to move the printing paper against the platen. To provide a ribbon band switching device capable of printing by switching a desired ribbon band to face a printing line on a platen while maintaining the ribbon band in a stable state.

Another object of the present invention is to provide a ribbon band switching device that switches to each ribbon band so that the distance between the printing ribbon and printing paper is always constant regardless of the ribbon position.

Composition of the invention Hereinafter, the present invention will be explained according to one embodiment.

FIG. 1 is an explanatory diagram showing the outline of a ribbon band switching device for a printer according to the present invention, FIG. 2 is an explanatory diagram showing ribbon zones in a printing ribbon, and FIG. 3 is a front view of a ribbon guide attached to a printing head. , FIG. 4 is a plan view of FIG. 3, FIG. 5 is a right side view of FIG. 3, and FIG. 6 is a schematic cross-sectional view taken along line A--A of FIG. 3.

In the figure, a carriage 1 shows a printing paper 4 mounted on the platen 2 by rotation of a drive motor (not shown) with respect to a guide rod 3 fixed to a main body frame (not shown) parallel to the axis of the platen 2.
It is inserted so that it can move back and forth along the printing line.

The print head 5 is mounted and fixed on the carriage 1, and as the carriage 1 moves, a number of electromagnetic solenoids (not shown) are used to control the front frame 5a.
A printing wire (not shown) supported within the printer is selectively driven to print characters, etc. in a dot matrix format on the printing paper 4 via a printing ribbon 13, which will be described later. Further, a pair of shaft portions 5b that rotatably support a ribbon guide 6, which will be described later, in the width direction of the printing ribbon 13 are integrally formed on both sides of the front end portion of the front frame 5a.

As is clear from the figure, this shaft portion 5b passes approximately through the center of the print end surface of the print head 5, and is located on an imaginary straight line perpendicular to the end surface, that is, in this embodiment, at the same height as the end surface.

The ribbon guide 6 has ribbon guide parts 7a and 8a that position the printing ribbon 13 substantially on the same plane as the printing end surface 5c at the tip of the front frame 5a, and also has a mounting hole 7 into which the shaft part 5b is inserted.
A pair of left and right guide bodies 7, 8 in which holes b, 8b are bored are connected to the upper parts of the guide bodies 7, 8,
When the ribbon guide 6 is rotated downward around the shaft portion 5b, a bridge portion 9 acts as a stopper that restricts the maximum rotational position of the ribbon guide 6 in the downward direction by contacting the upper surface of the front frame 5a. The guide bodies 7 and 8 have guide paths 10a and 11a for the printing ribbon 13 that extend rearward from the front end side in a slightly inclined state and constitute an arcuate portion on the inner wall surface thereof. Guideways 10a, 11
A printing end surface 5 of the printing head 5 inserted into the ribbon guide portion 7a and located substantially on the same plane as the ribbon guide portions 7a and 8a.
guide members 10 and 11 formed with slits 10b and 11b facing each other, and external teeth 12a having an appropriate number of teeth on the outer periphery of the guide body 7 at a concentric position from the center of the mounting hole 7a on one guide body 7 side. The gear 12 is integrally molded with resin.

The ribbon guide 6 holds the print ribbon 13 supported by the ribbon guide portions 7a and 8a on the front surface of the print head 5 so that it forms an arc that coincides with the center of rotation of the ribbon guide 6.

The printing ribbon 13 has first to fourth ribbon bands 13a to 13d of different colors from the upper end in the width direction, and is endless and folded and stored in a ribbon cassette 14 that is detachably attached to the main body case. , are stretched around guide shafts 15 fixed to the main body case at both ends of the platen 2, and are inserted through the ribbon guide 6 to form a print end surface 5.
It is located opposite to c. Inside the ribbon cassette 14 is a ribbon drive motor 1 fixed to the main body case.
A ribbon feeding roller 18 is installed which is rotationally driven by a driven roller 17 and which folds and stores the printing ribbon 13 while pinching it with a driven roller 17.

The drive device 19 is meshed with a step motor 20 mounted and fixed on the carriage 1, a drive gear 21 fixed to the rotating shaft of the step motor 20, and the gear 12, and is engaged with the step motor 20.
and an idle gear 22 having an appropriate reduction ratio that sequentially switches the first to fourth ribbon regions 13a to 13d every predetermined number of steps.

Next, the operation of this embodiment will be explained with reference to FIGS. 7 and 8.

First, in order to attach the printing ribbon 13 to the ribbon guide 6, first insert the slit 1 as shown by the dashed line in FIG.
Guide the printing ribbon 13 from 0b and 11b to the guide path 10.
a, 11a and positioned on the ribbon guide portions 7a, 8a which are substantially flush with the printing end surface 5c.

Then, after mounting the ribbon cassette 14 on the main body case and tensioning the printing ribbon 13 on the guide shaft 15, the shaft portion 5b is attached to the mounting holes 7b and 8b.
By inserting and fitting, the ribbon guide 6 is rotatably attached to the tip of the printing head 5, and the printing ribbon 13 is made to face the printing end surface 5c. Also, by attaching the ribbon guide 6 to the print head 5, the gear 12
is meshed with the idle gear 22 at an arbitrary position.

By the above means, the ribbon guide 6 is moved to the print head 5.
When the power switch is turned on after the stepper motor 20 is attached to the tip of the
The ribbon guide 6 is rotated by a number of steps corresponding to the ribbon bands 13a to 13d, and the ribbon guide 6 is rotated around the shaft portion 5b.
Rotate it downward as shown by the solid arrow in Figure 7, and
The ribbon band 13a of the ribbon band 13a is positioned opposite to the print end surface 5c, and the bridge portion 9 is brought into contact with the upper surface of the front frame 5a, thereby regulating the maximum rotational position of the ribbon guide 6 in the downward direction and controlling the step motor 20. The step motor 20 is caused to step out and the abutment position is set as the reference rotation position of the step motor 20.

When the print data is input, the controller controls the step motor 20 based on the ribbon band data.
is rotated by a predetermined number of steps corresponding to the ribbon band data from the rotational reference position, and the ribbon guide 6 is rotated in the upward direction shown by the solid line arrow in FIG. 8 about the shaft portion 5b to correspond to the ribbon band data. For example, after the ribbon band 13c is positioned opposite to the printing end surface 5c, the carriage 1 is moved back and forth along the printing lines of the printing paper 4, and the dot pattern data is accessed from a pattern memory (not shown) based on the printing data. is output to print head 5,
The printing wire is selectively driven to print characters, etc. in a color corresponding to the ribbon band 13c.
Then, similarly to the above operation, the control device rotates the step motor 20 by the number of steps calculated from its current position and the ribbon band data based on the next ribbon band data, and rotates the ribbon guide 6 around the shaft portion 5b. is rotated in the downward direction indicated by the broken line arrow in FIG. The previously printed characters, etc. are overprinted in the color corresponding to the switched ribbon band 13b, and the characters, etc. are printed in a desired color consisting of a mixed color of the colors corresponding to the ribbon bands 13b, 13c. .

When the ribbon guide 6 is rotated based on the ribbon band data and the desired ribbon bands 13a to 13d are opposed to the print end surface 5c, the ribbon guide 6
The printing ribbon 13 is attached to the ribbon guide portions 7a and 8a of
is supported in an arc that coincides with the center of rotation of the ribbon guide 6. Therefore, the printing ribbon 13 is rotated so that the distance between the printing paper 4 and each ribbon band 13a to 13d is constant. Contact of the print ribbon 13 with the print ribbon 4 can be avoided.

After the above operation, the printing paper 4 is fed by one printing line by the rotational drive of the platen 2, and then the ribbon bands 13a to 13d are sequentially switched according to the above operation, and the colors corresponding to the switched ribbon bands 13a to 13d are Characters, etc. are printed in a desired color consisting of a mixture of colors.

Therefore, in this embodiment, the printing ribbon 1 is rotated by rotating the ribbon guide 6 that holds the printing ribbon 13 in an arc shape.
In order to make the desired ribbon bands 13a to 13d in No. 3 face the print lines, the paper feed roller or The paper bail can be placed close to the printing line, reducing the unprintable area at the top and bottom of the printing paper 4, and holding the printing paper 4 in a stable state to prevent printing defects. be able to. Further, since the printing ribbon 13 is supported by the ribbon guide portions 7a and 8a of the ribbon guide 6 in an arc that coincides with the center of rotation of the ribbon guide 6, each ribbon band 13a
It is possible to avoid contact with the printing paper 4 by rotating the printing ribbon 13 so that the distance between the ribbon 13d and the printing paper 4 is always constant. Furthermore, when the power switch is turned on, the contact of the bridging portion 9 with the print head 5 actively causes the step motor 20, which is controlled in an open loop, to step out of step, and moves the corresponding contact position to the rotational reference position of the ribbon guide 6. Therefore, it is not necessary to attach the ribbon guide 6 to the drive device 19 in a positioned state, and operability can be improved.

In this example, a printing ribbon having four types of ribbon bands of different colors in the width direction is used.
Although the configuration is configured to print in multiple colors, the consumption efficiency of the printing ribbon is improved by using a printing ribbon that has at least two types of ribbon bands in the width direction of the same color, and printing while sequentially switching the ribbon bands. It is possible to do so.

Effects of the Invention As explained above, the present invention includes a platen that holds printing paper, a carriage on which a printing head is placed, and which can run parallel to the platen, and a carriage that runs parallel to the print line over almost the entire length of the printing line of the platen. It is stretched,
and a wide printing ribbon whose portions corresponding to both ends of the printing line are supported so as not to be movable in the vertical direction, and a rotation center located on an imaginary straight line starting from the printing end surface of the printing head and perpendicular to the printing end surface. The printing ribbon is supported rotatably based on the rotation center, and the printing ribbon is held along an arc-shaped part centered on the rotation center and held in an arc shape centered on the rotation center, and a printing head is provided between the arc-shaped parts. a ribbon guide on which a printed end surface is placed, and a driving means placed on the carriage and rotating the ribbon guide around the rotation center, the driving means driving the ribbon guide around the support shaft. Rotate around the
By arranging a desired ribbon band of the print ribbon to face the print head, it is possible to switch to the desired ribbon band while reducing the unprintable areas at the top and bottom of the print paper, and to reduce the distance between the print ribbon and the print paper. It is possible to provide a ribbon band switching device that switches to each ribbon band such that the .gamma.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of a ribbon band switching device for a printer according to the present invention, FIG. 2 is an explanatory diagram showing ribbon zones in a printing ribbon, and FIG. 3 is a front view of a ribbon guide attached to a printing head. , FIG. 4 is a plan view of FIG. 3, FIG. 5 is a right side view of FIG. 3, FIG. 6 is a schematic sectional view taken along line A-A in FIG. 3, and FIG.
This figure and FIG. 8 are explanatory views showing the operating states, respectively. In the figure, 1 is a carriage, 5 is a printing head, 5c is a printing end surface, 6 is a ribbon guide, 7a, 8a are ribbon guide parts, 13 is a printing ribbon, 13a to 13d
is a ribbon band, and 19 is a driving device.

Claims (1)

[Scope of Claims] 1. A platen that holds printing paper, a carriage on which a print head is placed and can run parallel to the platen, and a carriage that is stretched in parallel over substantially the entire length of the print line of the platen, and a wide printing ribbon whose portions corresponding to both ends of the printing line are supported so as not to be movable in the vertical direction; and a rotation center located on an imaginary straight line starting from the printing end surface of the printing head and orthogonal to the printing end surface. The printing ribbon is supported rotatably based on the rotation center, and the printing ribbon is held along an arc-shaped part centered on the rotation center and held in an arc shape centered on the rotation center, and a printing head is provided between the arc-shaped parts. a ribbon guide on which a printed end surface is arranged; and a driving means placed on the carriage and rotating the ribbon guide around the rotation center, the driving means driving the ribbon guide around the support shaft. 1. A ribbon band switching device for a printer, characterized in that the printing ribbon is rotated around the printing head so that a desired ribbon band of the printing ribbon faces the printing head.