JP3036230B2 - Ink ribbon switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output device for printing and printing, and more particularly to an ink ribbon switching device for a printer having an ink ribbon cassette mounted on a carriage.

[0002]

2. Description of the Related Art Conventionally, an ink ribbon switching mechanism as disclosed in Japanese Patent Application Laid-Open No. 63-254089 has been known. FIG. 8 is a plan view showing a conventional ink ribbon switching device. According to this, by controlling the movement of the carriage at a position where the carriage 2 has moved beyond the printing area, the switching levers 101 and 102 are pressed and slid to the right and left, and the ink ribbon cassette lift cam 1 is moved.
03 is rotated in one direction, the lift lever 104 is moved up and down to perform ink ribbon switching, and the switching lever is pressed and slid right and left until the requested ink ribbon is selected. Therefore, the sliding distance beyond the printing area required approximately ten and several millimeters.

[0003]

However, in the above-mentioned prior art, when the ink ribbon is switched, the switching lever has to be pressed and slid right and left at a position beyond the printing area by the carriage, so that the printing area cannot be changed. There is a problem that the moving space of the outer carriage is required to be more than ten and several millimeters on each side and the whole printer becomes large. In addition, there is a problem that the carriage has to be moved out of the print area for ribbon switching, and the throughput at the time of ribbon switching is reduced.

The present invention has been made in view of the above-mentioned drawbacks, and can minimize the moving space of the carriage outside the printing area, thereby simplifying the apparatus, reducing the size, reducing the cost, and improving the throughput. The purpose is to aim.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a carriage reciprocating along an output medium, an ink ribbon cassette mounted on the carriage and capable of moving up and down, and an ink ribbon cassette. An intermittent gear having a lift cam to be lifted, a gear rotating in accordance with the movement of the carriage, having a tooth portion meshing with the gear, and a neutral portion not meshing with the drive gear, and a coaxial gear with the intermittent gear. A friction gear rotatably supported with constant friction, and engagement / disengagement means for selectively stopping rotation of the intermittent gear in a state where the neutral portion of the intermittent gear and the gear face each other. I do.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic plan view of an embodiment in which the present invention is applied to a printer. FIG. 2 shows a side view of FIG. 1 viewed from the right side. First, 2 is a carriage, 3 is a platen opposed to the carriage 2, 4 is a printing paper fed by the platen 3, 5
Denotes a print head mounted on the carriage 2, and 7 denotes an ink ribbon 7a interposed between the print head 5 and the printing paper 4.
Is an ink ribbon cassette equipped with.

In the printer shown in FIG. 1, a carriage 2 on which a print head 5 is mounted is moved in a print digit direction by a print signal from a host computer, and is struck by a wire inside the print head 5, and the platen 3 is moved via an ink ribbon 7a.
The above-mentioned wire is hit on the printing paper 4 wound on the upper side to print characters and the like.

The carriage 2 moves on a drive shaft arranged in parallel with the platen 3 in the direction of the printing columns. A print head 5 is provided above the carriage 2. This print head 5
The ink ribbon storage section of the ink ribbon cassette 7 is mounted on the carriage 2 on the operator side (lower side in FIG. 1) corresponding to the rear side.

Reference numeral 7b denotes a rotation center shaft for vertically moving the leading end of the ink ribbon cassette 7, and the ink ribbon cassette 7 is supported rotatably about a rotation shaft 7b.

FIG. 3 is an exploded side view of the train wheel showing a winding mechanism for the ink ribbon 7a and a ribbon lift mechanism for shifting the ink ribbon cartridge 7 up and down. The ribbon winding mechanism and the ribbon lifting mechanism will be described with reference to FIGS.

The ribbon winding mechanism will be described. 23
Is a guide plate which is formed by cutting a rack gear and also serves as a guide for the carriage 2, 9 is a planetary gear configured to mesh with the guide plate 23, 10 is a planetary lever supported to swing the planetary gear 9 right and left, 13 is a ribbon transmission gear that meshes with the planetary gear 9, 11 is a ribbon transmission gear that similarly meshes with the planetary gear 9, 12 is a ribbon driven gear that meshes with the ribbon transmission gear 11, 8 is a ribbon drive gear and a drive shaft that winds the ink ribbon 7a. It is. When the carriage 2 moves in the X 'direction, the planetary gear 9 rotates in a counterclockwise direction (hereinafter, referred to as CCW). The planetary lever 10 rotates in the CCW direction and the planetary gear 9 meshes with the ribbon transmission gear 13, so that the ribbon transmission gear 13 rotates clockwise (hereinafter referred to as CW) to rotate the ribbon drive gear 8 in the CCW direction. When the carriage 2 moves in the X direction, the planetary gear 9
Rotates to CW. The planetary lever 10 rotates to CW, the planetary gear 9 meshes with the ribbon transmission gear 11, and the planetary gear 9
Rotate to W. As a result, the ribbon transmission gear 11 becomes CCW
To rotate. The ribbon driven gear 12 connected to the ribbon transmission gear 11 rotates to CW, and rotates the ribbon drive gear 8 to CCW. Therefore, the ribbon drive gear 8 always rotates CCW regardless of the moving direction of the carriage 2.

Next, the ribbon lift mechanism will be described.
14 is a lift transmission gear, 15 is a lift friction gear, 16 is a lift intermittent gear, 17 is a lift cam gear for sliding a lift lever 18 up and down, 19 is a home position detection sensor 2 fixed to the lift lever 18
The ribbon position shielding plate 5 is a trigger lever for stopping the intermittent lift gear 16 at a predetermined position.
The trigger lever 20 can swing in the W or CCW direction, and the trigger lever 20 has protrusions 20b and 20c formed at its tip. Reference numeral 21 denotes a return spring for applying a CW rotational force to the trigger lever 20, and reference numerals 30 and 31 denote trigger plates formed on the base frame 28 in a region beyond the printing region of the printer.

Next, the operation will be described with reference to FIGS. 4, 5 and 6. FIG. 4 is a wheel train plan view showing the intermittent gear mechanism during printing. During the bidirectional movement of the carriage 2, the lift transmission gear 14 connected to the ribbon drive gear 8 that always rotates CCW rotates to CW, and the lift friction gear 15 always rotates to CCW. The neutral portion 16 e of the intermittent lift gear 16 does not form a gear and does not receive the driving force of the lift transmission gear 14. Also intermittent lift gear 1
Numeral 6 is fitted into the notch 20a of the trigger lever 20 and the protrusion 16a of the intermittent lift gear 16 and does not rotate during printing. In this state, the lift friction gear 15 connected to the lift transmission gear 14 is rotating while exerting a constant frictional force on the intermittent lift gear 16. Next, when the ink ribbon cassette 7 is lifted, the carriage 2 is moved to the trigger plate 30 formed on the left and right sides of the base frame 28.
And 31. FIG. 5 is a wheel train plan view showing a trigger input state in the intermittent gear mechanism at the time of executing color switching. FIG. 6 is a wheel train plan view showing an operation when executing color switching. When the carriage 2 is moved in the X direction in FIG.
The protrusion 20 b of the trigger lever 20 is
To rotate the trigger lever 20 to CCW. When the carriage 2 is moved several mm in the X direction in this state, the lift friction gear 15 rotates in the CCW direction, and the disc spring 22
Exerts a frictional force by the load of
Rotate to W. The intermittent lift gear 16 meshes with the lift transmission gear 14. When the carriage 2 is moved in the X ′ direction in this state, the lift intermittent gear 16
Is rotated to CW. When the carriage 2 is moved by a predetermined amount, the lift cam gear 17 is rotated by 1/4 as shown in FIG. As shown in FIG. 6, even if the carriage 2 is moved by a predetermined amount or more, the second neutral portion 16f of the lift intermittent gear 16
And the lift transmission gear 14 face each other. At the same time, the protrusion 16b of the intermittent lift gear 16 does not fall into the notch 20a of the trigger lever 20, and the intermittent lift gear 16 is not rotated by the trigger lever 20. For this reason, the lift cam gear 17 stops at the place where it has rotated 1/4. FIG. 7 is a development view of a cam portion of the lift cam gear 17. The lift cam gear 17 has a gear that meshes with the intermittent lift gear 16 in the lower part, and a cam surface in the upper part that connects a plane part having four different heights on the circumference with a smooth slope.
In the state described above, the lift lever 18 stops at the portion B in FIG. 7 and raises the ink ribbon cassette 7 by one step to execute the ribbon lift. If this operation is performed twice, the lift cam gear 17 becomes １ ／.
Rotation is performed three times, three-quarters of a rotation is performed, and four times, one rotation is performed. Each time the lift cam gear 17 makes a 1/4 turn, the lift lever 18 ascends to the portions A, B, C, and D using the cam portion formed on the lift cam gear 17 as a guide as shown in FIG. By moving the lever 18 up and down, the ink ribbon cassette 7 is lifted in four stages. As described above, the distance that the carriage 2 moves beyond the printing area is the distance until the gear portion of the intermittent lift gear 16 meshes with the lift transmission gear 14, and can be moved by about 2 to 3 mm.

In this embodiment, the A portion (black), B portion (cyan), C
(Magenta) and D (yellow). The number of rotations of the lift cam gear 17 is controlled such that a signal for moving the carriage 2 is sent according to the required color of the ink ribbon 7a to be selected so that a predetermined color ink ribbon can be selected.

Here, the color home detection operation will be described. When the power of the printer is turned on, the ribbon position must be detected. Therefore, in this embodiment, the ribbon position shielding plate 19 attached to the lift lever 18 with the lift lever 18 at the position A (black) of the lift cam 17 is shown in FIG. It is set to be at the lowest point as shown by the solid line. When the carriage 2 is moved in the X 'direction in this state, the ribbon position shielding plate 19
5 into the gap 25a. FIG. 2 is a diagram showing a positional relationship of the ribbon position shielding plate 19 with respect to the position detection sensor 25. The position detection sensor 25 is, for example, of a photo interrupter type, and includes a light emitting element 25b such as an LED and a light receiving element 25c such as a phototransistor.
Are provided on both sides of the gap 25a, and if there is no light-shielding object in the gap 25a, light emitted from the light emitting element 25b enters the light receiving element 25c, and the internal phototransistor is turned on by the photo transistor.
The state becomes the N state. On the other hand, when there is a light shielding object in the gap 25a, the light of the light emitting element 25b does not enter the light receiving element 25c, and the internal phototransistor is turned off. Therefore, when the ink ribbon cassette 7 is raised above the black position as described above, the ribbon position shielding plate 19
Does not enter the gap 25a, and the phototransistor is turned on. Conversely, when the ribbon cassette 7 is lowered to the black position, the ribbon position shielding plate 19 is lowered to the position of the gap 25a, moves into the gap 25a by moving the carriage 2 in the X 'direction, and the phototransistor is turned off.

[0017]

As is apparent from the above description, according to the ribbon switching apparatus of the present invention, the intermittent mechanism and the engaging / disengaging means for stopping the rotation of the intermittent gear are provided between the drive gear and the lift cam. Therefore, ribbon switching can be performed without using a drive source dedicated to the ribbon lift. As a result, the size and cost of the apparatus can be reduced, and the moving space of the carriage outside the printing area can be reduced to 10% or less of the conventional one, so that the apparatus can be simplified, downsized, reduced in cost, and throughput can be reduced. Can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a ribbon switching device according to an embodiment of the present invention.

FIG. 2 is a side view of FIG. 1 as viewed from the right.

FIG. 3 is an expanded side view of the train wheel in the embodiment of FIG. 1;

FIG. 4 is a wheel train plan view showing the intermittent mechanism during printing (during standby) according to the embodiment of the present invention.

FIG. 5 is a wheel train plan view showing a trigger input state of the intermittent mechanism according to the embodiment of the present invention.

FIG. 6 is a wheel train plan view showing the operation of the intermittent mechanism according to the embodiment of the present invention.

FIG. 7 is a development explanatory view of a lift cam for shifting the lift lever of the present invention in four stages.

FIG. 8 is a plan view showing a conventional ink ribbon switching device.

[Brief description of reference numerals]

 2 Carriage 3 Platen 4 Printing paper 5 Print head 7 Ink ribbon cassette 8 Ribbon drive gear 9 Planetary gear 10 Planetary lever 11 Ribbon transmission gear 12 Ribbon driven gear 13 Ribbon transmission gear 14 Lift transmission gear 15 Lift friction gear 16 Lift intermittent gear 17 Lift cam gear Reference Signs List 18 Lift lever 19 Ribbon position closing plate 20 Trigger lever 21 Return spring 22 Disc spring 23 Guide plate 25 Position detection sensor 28 Base frame 30 Trigger plate right 31 Trigger plate left 101 Switching lever right 102 Switching lever left 103 Lift cam 104 Lift lever

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 35/10 B41J 33/22

Claims (1)

(57) [Claims] A carriage reciprocating along an output medium, an ink ribbon cassette mounted on the carriage and capable of moving up and down, a lift cam for lifting the ink ribbon cassette, and rotating in accordance with the movement of the carriage. An intermittent gear having a gear, having a tooth portion that meshes with the gear and a neutral portion that does not mesh with the gear; a friction gear rotatably supported on the intermittent gear coaxially and rotatably with a constant friction with respect to the intermittent gear; An ink ribbon switching device, comprising: an engagement / disengagement means for selectively stopping rotation of the intermittent gear in a state where the neutral portion of the intermittent gear faces the gear.