JPH0858207A - Dot impact type serial printer - Google Patents

Abstract

PURPOSE: To smooth the taking-up of a multicolor ribbon even if a different color is selected and to enhance the reliability of the whole of a dot impact type serial printer. CONSTITUTION: A cassette holder 3 is constituted so as to be freely reciprocally moved in the direction crossing the feed direction of a multicolor ribbon 4A at a right angle and a positive motion cam mechanism energizing the cassette holder 3 to reciprocally move the same and stopping the same at a predetermined position is provided. Further, the first gear mechanism energizing the operation of the positive motion cam mechanism, the second gear mechanism energizing the operation of a ribbon running drive mechanism 6 and the stepping motor 20 energizing the operation of the respective gear mechanisms are provided. When the stepping motor 20 is rotated in one direction, the first gear mechanism functions and, when the stepping motor 20 is rotated in other direction, the second gear mechanism functions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot impact type serial printer in which a multicolor ink ribbon cartridge is mounted on a print head carrier.

[0002]

2. Description of the Related Art Conventionally, there are the following two systems as a system of a system for switching and executing a ribbon traveling drive and a ribbon change drive by the same drive source.

The first method is, as shown in FIGS. 5 to 6, a stepping motor 50 having a motor gear 50A.
And a swing arm 51 which is supported by the rotation shaft of the stepping motor 50 and swings in the rotation direction of the stepping motor 50, and a planetary gear 52 which is mounted on the swing arm 51 and which constantly meshes with the above-described motor gear 50A. When,
It has. Further, two driven gears 5 arranged for meshing with the planet gears 52 and having different purposes of operation.
3 and 54, one of the driven gears 53 is provided with a drive shaft 55 for ribbon feed, and the other of the driven gears 54 is provided.
A camshaft 58, to which a ribbon changing cam 57 corresponding to the cam follower of the multicolor ink ribbon cassette is fixed, is fixed to. As a result, when the stepping motor 50 rotates in one direction (F direction), the planetary gear 52 swings in the rotational direction and meshes with one of the driven gears 53 to perform a ribbon feed operation.
Is rotated in the opposite direction (G direction), the other driven gear 5
4 is engaged with the ribbon change operation (Japanese Patent Application Laid-Open No. 3-36077).

In the second method, as shown in FIG.
Stepping motor 60 and this stepping motor 6
Gear 61 with a one-way clutch 61A that transmits the rotational force to the ribbon feed shaft 66 when rotating in one direction of 0, and the one-way clutch 6 that receives the rotational force when rotating in the reverse direction to operate the ribbon change
2A built-in cam 62 with a one-way clutch (Japanese Patent Laid-Open No. 61-220887).

In FIG. 7, the ribbon base 63 is
The print head side can be turned up and down via a phase shaft 64 fixedly mounted on the ribbon base 63, whereby the color of the color ribbon 69 is selected. Reference numeral 64a indicates a cam surface 62a of the cam 62.
8 shows a rotating ball mounted on the tip (lower end in FIG. 7) of the phase shaft 64 described above so as to roll. Also, reference numeral 60A
Indicates a motor gear, and reference numerals 63A and 63B indicate engagement mechanisms for the ribbon base 63.

[0006]

SUMMARY OF THE INVENTION In the above conventional example,
The former first method (in the case of FIGS. 5 to 6) is the rotation of the stepping motor 50 until the planetary gear 52 is swung to the driven gear gear 54 for ribbon change and meshed when switching to the ribbon change operation. Since the corner is indefinite,
In order to control the rotation angle of the cam 57 corresponding to the position of the multicolor ribbon (not shown), it is necessary to take measures such as setting the angle detection sensors for the number of ribbon colors, which not only leads to an increase in the number of parts. However, there is an inconvenience that the position control becomes complicated.

The latter second method (in the case of FIG. 7)
Uses two one-way clutches, there is a disadvantage that the ribbon feed / ribbon change mechanism becomes expensive.

Further, in each of the above-mentioned conventional examples, as described above, when the print color is selected, the running surface of the multicolor ribbon is undulated with respect to the print head. For this reason, when the multicolor ink ribbon cassette is almost horizontal (the surface of the multicolor ribbon is vertical), the print head is located in the center of the multicolor ribbon, so that extra force is applied to the multicolor ribbon. However, when the multicolor ink ribbon cassette is tilted, the print head contacts one side of the multicolor ribbon, so that tension is applied only to one side of the multicolor ribbon at the time of feeding, so that the winding is smoothly performed. However, the multi-color ribbon is hindered from running, and the reaction force from the multi-color ribbon to the press dot at the time of printing is not uniform due to the inclination of the print head surface. There is an inconvenience that the reaction force becomes larger as the dot becomes larger and the printed dot becomes thinner.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to improve the inconveniences of the prior art example, to make the winding of the ink ribbon smooth even if different colors are selected, and to improve the reliability of the entire apparatus. The purpose is to provide a printer.

[0010]

According to the present invention, a carrier frame for fixedly holding a print head, a multicolor ink ribbon cassette mounted on the carrier frame via a cassette holder, and a multicolor ink ribbon cassette are fed out. A ribbon guide that guides the multicolor ribbon to the print head and a ribbon traveling drive mechanism that applies a traveling force to the multicolor ribbon are provided.

Further, the cassette holder and the ribbon guide are reciprocally movable in a direction orthogonal to the feed direction of the multicolor ribbon, and the cassette holder and the ribbon guide are urged to reciprocate and can be stopped at a predetermined position. The positive cam mechanism configured as described above is provided.

Further, the first gear mechanism for urging the operation of the positive cam mechanism, the second gear mechanism for urging the operation of the ribbon traveling drive mechanism, and the operation of each of the gear mechanisms. And a stepping motor.

When the stepping motor rotates in one direction, the first gear mechanism functions, and when the stepping motor rotates in the other direction, the second gear mechanism functions. I am collecting. This aims to achieve the above-mentioned object.

[0014]

[Operation] When the cam driving means (stepping motor) 20 is rotated in the normal direction, first the positive cam mechanism is operated via the first gear mechanism, and the cassette holder 3 and the multicolor ink ribbon cassette 4 as a whole are connected to the platen. The platen is moved in a direction orthogonal to the platen while maintaining the parallel state. Positioning of the color of the ribbon to be printed is performed by rotating the stepping motor 20 by a predetermined number of steps from the home position of the eccentric disc cam (eccentric cam) 7A.

On the other hand, when the cam drive means (stepping motor) 20 is rotated in the reverse direction, the ribbon traveling drive mechanism is operated via the second gear mechanism to perform the ribbon feed operation. In this case, due to the action of the positive cam mechanism (the idling operation of the one-way clutch 7C), the eccentric disc cam (excene cam) 7A does not rotate, and the current ribbon color position is maintained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In the embodiment shown in FIGS. 1 to 4, a carrier frame 2 for fixedly holding a print head 1, a multicolor ink ribbon cassette 4 mounted on the carrier frame 2 via a cassette holder 3, and The multicolor ink ribbon cassette 4 is provided with a ribbon guide 5 that guides the multicolor ribbon 4A to the print head 1, and a ribbon traveling drive mechanism 6 that applies a traveling force to the multicolor ribbon 4A.

The multicolor ink ribbon cassette 4 is formed so that the cassette holder 3 and the ribbon guide 5 can slide in the direction orthogonal to the feed direction of the multicolor ribbon 4A. Further, the cassette holder 3 and the ribbon guide 5 are provided with a positive-moving cam mechanism 7 configured to urge the reciprocating movement and stop at a predetermined position.

Further, a cam drive means 20 for driving the positive cam mechanism 7 at a predetermined timing is provided alongside the positive cam mechanism 7.

As will be described later, the positive cam mechanism 7 includes an eccentric disc cam 7A which is rotationally driven at a predetermined position, a rectangular follower frame body 7B inscribed in the eccentric disc cam 7A, and an eccentric circle. The one-way clutch 7C (see FIG. 2) incorporated in the rotary shaft 7a of the plate cam 7A is provided. This one-way clutch 7C is actually a disk cam 7A on the rotating shaft 7a.
It is press-fitted and integrated into a gear 17 that is coaxially equipped.

Then, the follower frame body 7B therein is fixedly mounted on the back surface of the above-mentioned cassette holder 3, so that the cassette holder 3 operates together with the operation of the positive cam mechanism 7 and feeds the multicolor ribbon 4A. The multicolor ribbon 4A is reciprocated in a direction orthogonal to the direction, and the multicolor ribbon 4A is ribbon-changed with respect to the print head 1.

The positive cam mechanism 7 is actuated by the eccentric disc cam 7A to operate as a signal output means for outputting the reference position information for setting the stop position of the cassette holder 3 described above. A switch 7S is installed side by side. A micro switch is actually used as the starting switch 7S. This start switch (micro switch)
The output of 7S is sent to a control means (not shown) for signal processing, and is treated as a reference timing of a start / stop signal of a stepping motor described later.

In more detail, a multicolor ink ribbon cassette 4 for accommodating a multicolor ribbon 4A in which a plurality of colors are arranged in parallel with the ribbon feed direction is supported by the carrier frame 2 and ribbons with respect to the carrier frame 2. The cartridge holder 3 is held so as to be slidable in the direction perpendicular to the feed direction.

The carrier frame 2 on which the multicolor ink ribbon cassette 4 and the print head 1 are mounted is configured to be guided by guide shafts 2A and 2B and to perform a reciprocating motion while performing a printing operation along the platen 9. There is.

2 and 3 show an example of a ribbon change mechanism portion for driving and controlling the above-mentioned respective portions.

In FIG. 2, a stepping motor 20 for driving a ribbon feed and a ribbon change is fixed to the carrier frame 2, and a motor gear 11 is fixed to the stepping motor shaft 20a.
The idle gear 12 is meshed with the motor gear 11,
The shaft 12a fixed to the carrier frame 2 is rotatably positioned about a rotation shaft. The planetary gear 13 meshes with the idle gear 12 and is fixed to a planetary gear plate 14 rotatably mounted about a shaft 12a.
It is rotatably attached with 3a as a rotation axis. The idle gear 12, the planetary gear 13, and the planetary gear plate 14 that supports the planetary gear 13 form a second gear mechanism 10B.

The planetary gear 13 is further set on the circular orbit of the planetary gear 13 at a position where it meshes with a ribbon feed gear 15 integrated with a ribbon feed roller (not shown) inside the multicolor ink ribbon cassette 4. ing. The ribbon traveling drive mechanism 6 described above is configured by a series of gear mechanisms from the motor gear 11 to the ribbon feed gear 15.

On the other hand, the one-way clutch gear 17 into which the one-way clutch 7C is press-fitted has a cam shaft 7a which meshes with the motor gear 11 and is rotatably held by the carrier frame 2 as an axis. An eccentric disc cam (eccentric cam) 7A having an eccentric amount corresponding to a stroke required for ribbon change is press-fitted into the cam shaft 7a. The one-way clutch 7C and the one-way clutch-equipped gear 17 constitute a first gear mechanism 10A.

This eccentric disc cam (extense cam) 7A
As described above, the cassette holder 3 holds the multicolor ink ribbon cassette 4 and is slidable with respect to the carrier frame 2 in the direction perpendicular to the ribbon feed direction.
It is engaged with a follower frame body 7B as a cam follower fixed to. This constitutes the positive cam mechanism 7.

A pin 22 is press-fitted into the eccentric disc cam (excene cam) 7A, and when the eccentric disc cam (eccentric cam) 7A reaches a predetermined rotation angle by a micro switch 7S fixed to the carrier frame 2, it is detected. Is set to.

Next, the operation of the above embodiment will be described with reference to FIGS.
Will be explained.

FIG. 3 shows a case where the motor gear 11 is normally rotated (arrow B). In this case, the planetary gear plate 14 receives a rotational moment in the direction of arrow C, so that the planetary gear 13
Is out of mesh with the ribbon feed gear 15.

On the other hand, since the one-way clutch 7C locks the camshaft 7a with the rotational force transmitted to the gear 17 with the one-way clutch, the eccentric disc cam (eccentric cam) 7A is rotated to move the follower frame (cam follower) 7B. The multicolor ink ribbon cassette 4 is moved by sliding the fixed cassette holder 3. The color of the ribbon to be printed is positioned by rotating the stepping motor 20 by a predetermined number of steps from the home position of the eccentric disc cam (excene cam) 7A detected by the start switch (micro switch) 7S.

On the other hand, in FIG. 4, when the motor gear 11 is rotated in the reverse direction (arrow D), the planet gear plate 14 is moved to the arrow E.
The planetary gear 13 meshes with the ribbon feed gear 15 to perform the ribbon feed operation because the rotational moment is received in the direction of. In this case, since the one-way clutch 7C idles between itself and the camshaft 7a, the eccentric disk cam (excene cam) 7A is not rotated and the current ribbon color position is maintained, whereby the ribbon feed operation is executed. .

[0035]

As described above, according to the present invention, the cassette holder holding the multicolor ink ribbon cassette on the carrier frame is slid at a right angle in the ribbon feed direction, so that the ribbon color can be switched. Since the multicolor ribbon always runs parallel to the printing surface of the print head, there is no change in the load when the multicolor ribbon is running before and after the ribbon color is switched, and therefore, at the time of feeding, It is possible to completely eliminate the disadvantage of the conventional example in which tension is applied only to one side of the multicolor ribbon, and therefore, the winding and running of the multicolor ribbon can be performed smoothly, and at the same time, the multicolor ribbon can be performed. Can always contact the print head with the same tension even if the ribbon-shaped position changes, and as a result, uniform print quality can be maintained. In addition, by the action of the first gear mechanism and the second gear mechanism, ribbon color switching and ribbon running can be executed smoothly, and therefore, the reliability of the entire apparatus can be improved, which is unprecedented. It is possible to provide a dot impact type serial printer.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a partially sectional front view taken along the line AA of FIG.

FIG. 3 is a configuration diagram showing a mutual relationship when the respective constituent members disclosed in FIG. 2 are viewed from the multicolor ink ribbon cassette side.

FIG. 4 is an explanatory diagram showing the operation of FIG.

FIG. 5 is a configuration diagram showing one conventional example.

6 is a partially sectional front view of FIG.

FIG. 7 is an explanatory diagram showing another conventional example.

[Explanation of symbols]

 1 Print Head 2 Carrier Frame 3 Cassette Holder 4 Multicolor Ink Ribbon Cassette 4A Multicolor Ribbon 5 Ribbon Guide 6 Ribbon Traveling Drive Mechanism 7 Positive Moving Cam Mechanism 7A Eccentric Cam (Execen Cam) 7B Follower Frame Body (Cam Follower) 7C One Way Clutch 10A No. 1 gear mechanism 10B 2nd gear mechanism 20 stepping motor

Claims (3)

[Claims] 1. A carrier frame for fixedly holding a print head, a multicolor ink ribbon cassette mounted on the carrier frame via a cassette holder, and a multicolor ribbon fed from the multicolor ink ribbon cassette to the print head. In a dot impact type serial printer having a ribbon guide for guiding and a ribbon traveling drive mechanism for applying a traveling force to the multicolor ribbon, the cassette holder and the ribbon guide are orthogonal to the feed direction of the multicolor ribbon. The cassette holder and the ribbon guide are provided with a positive cam mechanism that is configured to be able to stop at a predetermined position while being configured to be reciprocally movable in any direction. A first gear mechanism for
A second gear mechanism for energizing the operation of the ribbon traveling drive mechanism and a stepping motor for energizing the operation of each gear mechanism are provided, and when the stepping motor rotates in one direction, the first gear mechanism is used. The dot impact serial printer is characterized in that when the stepping motor rotates in the other direction, the second gear mechanism operates. 2. The first gear mechanism includes a one-way clutch that engages when the stepping motor rotates in one direction and idles when the stepping motor rotates in the other direction. The dot impact type serial printer according to claim 1, characterized in that. 3. The second gear mechanism engages with the ribbon traveling drive mechanism when the stepping motor rotates in the other direction, and the ribbon drive mechanism when the stepping motor rotates in the one direction. The dot impact serial printer according to claim 1, further comprising a planetary gear mechanism separated from the traveling drive mechanism.