JPS6277977A - Multicolor ribbon switching device - Google Patents

Abstract

PURPOSE:To provide the titled device capable of speedily switching a multicolor ribbon, by providing a detecting switch which is opened or closed by a driving gear when the gear is rotated to the position of the second angle beyond the range of the first angle in an initializing operation, thereby detecting a color band of the multicolor ribbon which is opposed to a printing head at that time. CONSTITUTION:When printing in one of black, red, blue and yellow colors is conducted, a driving gear 18 is located at the corresponding one of positions P1-P4, the angles between the positions being theta1, theta2, theta3, respectively. The position P1 is an initial position, and when the gear 18 is located at the position P1, a black color band 5a is opposed to a printing head 2. In ribbon shifting for switching the color during a printing operation, the driving gear 18 is reciprocally rotated in the range of the total angle theta of the angles theta1, theta2, theta3. Initialization is performed on turning ON a power source for a printer. At this time, the driving gear 18 is rotated clockwise to a position P0, at whichever of the positions P1-P4 the gear 18 has been located. At the position P0, a detecting switch SW is closed by a pressing piece 18b of the driving gear 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a multi-color ribbon cassette having a multi-color ribbon impregnated with different inks in a plurality of color bands partitioned parallel to the longitudinal direction. The present invention relates to a multicolor ribbon switching device for switching the color of a ribbon facing a print head in a printer.

[Prior Art] As an example of a multicolor ribbon switching device for a serial printer, British Patent Application Box No. 35407/78 is known. This device is equipped with a ribbon on the carriage of the print head to selectively place any one of a plurality of horizontally divided elongated color bands of the multicolor ribbon between the print head and the platen. a shifter and a set cam that engages a cam follower of the ribbon shifter to set the ribbon shifter to switch a color band opposite the printhead to a desired color in response to the position of the printhead on the left margin side; and reset cam means for engaging a cam follower of the ribbon shifter to reset the ribbon shifter before selecting a new shift position. Both cam means are fixedly arranged on the guide shaft of the carriage.

Furthermore, a ribbon holder that supports a pair of ribbon spools wound with ink ribbon has a base linked with an electromagnetic solenoid, and a lever combination is used to switch the color band facing the ribbon print head (for example, , Japanese Patent Publication No. 46-16057, Japanese Patent Application Publication No. 53-82526
Publication No.).

[Problems to be Solved by the Invention] In the first known technique, the reset cam means corresponds to the initialization mechanism, but the ribbon shift is performed by program-controlling the movement of the carriage toward the left margin side away from the printing area. Since this is a control method, the movement of the carriage is complicated, and the ribbon cannot be shifted or switched quickly.

The second known technique has a large number of parts, resulting in a complicated configuration and is troublesome to assemble. Further, in the case of a multicolor ribbon switching device having such a configuration, a detection switch is often used to detect the color band of the ribbon facing the print head at the initial position. At this time, the detection switch is usually disposed at a position where the receiver engages with the stand and can be opened and closed when the multicolor ribbon switching device is in its initial position. However, such a simple arrangement of detection switches would cause the following problems. That is, even though the detection signal is used only during initialization, ribbon shifting is frequently repeated during printing operations, making the detection switch unnecessary and resulting in frequent repeated opening and closing. When using a mechanical switch such as a microswitch as a detection switch, there is a natural limit to the number of times such a mechanical switch can be used, and therefore the detection switch will reach the end of its life within a short period of time.

An object of the present invention is to provide a multicolor ribbon switching device that can quickly switch multicolor ribbons.

Another object of the present invention is that a detection switch for detecting the color band of the multicolor ribbon facing the print head in the initial position is opened and closed only at the time of initialization.

The purpose is to ensure sufficient durability of the detection switch.

Means for Solving Problem C] In order to achieve the above object, in the multicolor ribbon switching device according to the present invention, a plurality of color bands partitioned parallel to the longitudinal direction are impregnated with inks of different colors. a ribbon cassette having a multicolored ribbon; a switching plate movably supported by a support plate, carrying the ribbon cassette and positioning the ribbon cassette so that one of the color bands faces the print head; and a drive. a drive gear that is normally rotated by a motor within a first angular range and rotated to a second angular position beyond the first angular range upon initialization; and a drive gear that rotates relative to the drive gear. a transmission shaft that is unrotatably fitted and rotated; a transmission lever that is unrotatably fitted and displaced relative to the transmission shaft and moves the switching plate; 1. A detection switch that is opened and closed by the drive gear when rotated to a second angular position exceeding the angular range of 1, and detects the color band of the multicolor ribbon facing the print head at that time. It is composed of.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be exemplarily described with reference to the drawings.

In FIG. 1, a print head 2 is disposed in front of a cylindrical platen 1. As shown in FIG. The print head 2 is reciprocated along the axial direction of the platen 1 between arms 3a and 3b of the ribbon cassette 3 via a carriage (not shown). Between the platen 1 and the print head 2, there are a recording medium 4 and an arm 3a of a ribbon cassette 3.
An ink ribbon 5 exposed from 3b is inserted.

The ink ribbon 4 is endless, and most of it is stored inside the cassette 3 in a zigzag manner.
A ribbon drive device (not shown) causes the ribbon to run counterclockwise, for example.

Further, as shown in FIGS. 2 and 3, this ink ribbon 5 has four color bands 5a to 5d divided parallel to its longitudinal direction, and the color bands 5a to 5d include, for example, , impregnated with black, blue, red, and yellow inks. As shown in FIG. 11, on the front end surface 2a of the print head 2,
Printing elements 2b such as needles are arranged in a vertical line, and any one of the color bands 5a to 5d of the ink ribbon 5 is opposed to them.

FIG. 11 shows the initial state, in which the black color band 5a faces the printing element 2b. The switching of the color band opposite the printing element 2b will be explained in detail below.

The ribbon switching device of the present invention is integrated into a unit in this embodiment, and as shown in the first figure, the ribbon switching device includes a casing 6°7 that closely opposes both sides of the ribbon cassette 3, and a casing 6°7 located along the rear side of the ribbon cassette 3. It has a connecting bar 8 which extends and connects the casing 6.7. A stepping motor 9 as a drive motor is provided on the outer surface of the casing 6, and a switching plate 10.11 that moves up and down by the operation of the motor 9 is provided on the opposing surface of the casing 6.7. On the shoulder of this switching plate 10.11, there is a ribbon cassette 3.
Attachment claws 30 to 3e protrudingly formed on both sides are removable. Therefore, when the switching plate 10.11 moves up and down, the ribbon cassette 3 placed horizontally between the switching plates 10.11 also moves up and down, thereby facing the printing element 2c shown in FIG. 11. Ribbon 5
The color band is switched.

The detailed structure of the switching plate 10 will be explained with reference to FIGS. 4 to 6.

As shown in FIGS. 5 and 6, the shoulder portion of the switching plate 10 has a recess 10 in which locking claws IQa, 10b and a mounting claw 3d, which can detachably capture the mounting claws 3c, 3e of the ribbon cassette, can be placed.
c and are formed. Further, on the back side of the switching plate 10, elastic legs 10d, IQd, guide bins lQe, 10e, and hooks 10f are integrally formed to protrude.
0d and guide pins lQe and 10e are arranged in a vertical line. As shown in FIG. 4, the guide bins 10e, 10e are slidably fitted into the guide groove 6a formed on the opposing surface of the casing 6, and the legs 10d, 10d are fitted into the guide groove 6a.
The switching plate 10 is captured by the opposing surface of the casing 6 by being locked to the inner edge of the casing 6. The hook 10f of the switching plate is movable within the groove 6b on the inner surface of the casing 6,
A biasing spring 12 is engaged between the hook 6C and the hook 10f, which are integrally formed at the lower end of the groove 6b.

Therefore, the switching plate 10 is always urged downward by the spring force of the spring 12.

Next, the transmitter (R) that converts the rotation of the motor 9 into vertical movement of the switching plate 10 will be explained with reference to FIGS. 7 to 10.

Inside the casing 6, as shown in FIGS. 7 and 8, there is a motor pinion 1 fixed to the output shaft 13 of the motor 9.
4 has entered, and meshes with a gear 16 rotatably supported by a support 15 formed integrally with the casing 6. A pinion 17 formed integrally with the gear 16 meshes with teeth of a fan-shaped drive gear 18. Drive gear 18
The rotation of the motor 9 causes the pinion 14. It reciprocates around the axis of the transmission shaft 19 via the gear 16 and pinion 17, and this rotational motion is transmitted to the transmission shaft 19. The transmission shaft 19 is connected to the casing 6.7 as shown in FIG.
It is inserted into the recess 8a of the connecting bar 8 that connects the
Its ends extend rotatably into the casing 6.7. The transmission shaft 19 has a non-circular cross-sectional shape, and the base of the drive gear 18 is fitted into one end of the transmission shaft 19 so as to be relatively non-rotatable. The drive gear 18 is rotated counterclockwise in FIG. 7 by a biasing spring 20 that is hooked between a hook 18a formed protruding from the back surface thereof and a hook 6c formed protrusively from the corner of the casing 6. energized. Further, within the casing 6, a transmission lever 21 that is fitted in a relatively non-rotatable manner to the transmission shaft 19 is disposed close to and facing the front surface of the drive gear 18, and a switching plate 1 is provided in a long groove 21a at the tip of the transmission lever 21.
0 guide pin 10e is engaged. Therefore, the rotational movement of the drive gear 18 is transferred to the transmission lever 2 via the transmission shaft 19.
1 to move the switching plate 10 up and down. A pressing piece 18b for opening and closing a microswitch SW for detecting the position of the ribbon 5 is integrally formed and extended on the back side of the drive gear 18.

As clearly shown in FIGS. 8 and 9, the switch SW is centered around the protrusion 6d on the inner surface of the casing 6, i.e. around the drive gear 18. It is fixed to an adjustment lever 22 that is rotatable concentrically with the rotation center of the transmission shaft 19 or the transmission lever 21. The adjustment lever 22 is configured such that the adjustment lever 22 can be rotated without inhibiting the rotation of the adjustment lever 22 by engaging an elastic pawl 6e integrally formed protruding from the inner surface of the casing 6 with a groove 22a having an arc concentric with the center of rotation. It is captured on the inner surface of the casing 6. Figure 3.

As shown in FIGS. 8 and 9, a grooved elastic head 23a of the adjustment shaft 23 is attached to the outer surface of the casing 6 at a position facing the tip of the adjustment lever 22. As shown in FIGS. A cylindrical body 6f is provided on the inner surface of the casing 6 so as to surround the adjustment shaft 23.
are integrally formed.

A low red mark (not shown) is engraved on the inner peripheral surface of the cylinder 6f, and by engaging the elastic arm 23b of the adjustment shaft 23, the adjustment shaft 23 can be maintained at a desired adjustment position. It has become. An eccentric pin 23c, which is formed to protrude from the adjustment shaft 23, is engaged with a long groove 22b at the tip of the adjustment lever 22. This allows adjustment lever 2
2 is rotatable around the protrusion 6d via the eccentric pin 23c by turning the adjustment shaft 23, and the drive gear 1
The positional relationship between the pressing piece 18b of No. 8 and the switch SW can be adjusted.

Next, the transmission mechanism within the Kelsinga will be explained with reference to FIGS. 9 and 10.

The transmission lever 24 disposed inside the casing 7 has a cylindrical portion 24b connected to the rear end via a U-shaped spring portion 24a, and this cylindrical portion 24b is connected to the end of the transmission shaft 19. The adjustment screw 25, which passes through the protruding part 24c protruding from the cylindrical part 24b, is screwed into the protruding part 24d at the transmission lever side end of the spring part 24a. By turning this adjustment screw 25, the amount of opening of the U-shaped spring portion 24a is adjusted, and as a result, the position of the tip of the transmission lever 24 can be adjusted.

The switching plate 11 facing the side surface of the casing 7 is the front.

It has a symmetrical shape with the switching plate 10 described above, and is captured on the side surface of the casing 7 with a similar structure.

That is, as shown in FIG. 10, the switching plate 11 includes locking claws 11a and llb that can detachably capture the mounting claws 3c and 3e of the ribbon cassette, and a recess 11 that can place the mounting claws 3d.
c is formed on the shoulder.

Further, on the back side of the switching plate 10, there is an elastic leg portion 11d.

11d, guide pins lle and lie, and a hook 11f are integrally formed to protrude, and the leg portion 11d.

The lid and guide pins lie are lined up in a vertical line. A guide groove 7a formed on the inner surface of the casing 6
The switching plate 11 is captured on the inner surface of the casing 7 by the guide pins lie and lie being slidably fitted into each other, and the legs lid being engaged with the inner edges of the guide grooves 6a. The hook llf of the switching plate 11 is connected to the casing 7
A biasing spring 26 is engaged between a hook 7c and a hook 11f, which are integrally formed at the lower end of the groove 7b.

Therefore, the switching plate 11 is always urged downward by the spring force of the spring 26. The long groove 24e formed at the tip of the transmission lever 24 has a guide pin li of the switching plate 11.
Since e is engaged, the transmission lever 24 is swung through the transmission shaft 19, and the switching plate 11 moves up and down accordingly.

The multicolor ribbon switching device configured as a unit as described above uses the locking claws 27a and 27b integrally formed on the lower surfaces of the casings 6 and 7 to switch the platen 1 etc. as shown in the third figure. Supporting printer frame 28
It can be removably mounted in a predetermined position. The connector 29 provided on the front end surface of the casing 6 is a switch S for detecting the position of the motor 9 and the ribbon 5.
This is for connecting W to a control circuit (not shown).

Next, initialization of the multicolor ribbon switching device of the present invention will be explained.

When printing is performed in black, red, blue, and yellow, the driving gear 18 is located at positions P1 to P1 in FIG. 12, respectively. The angles between the P position and the P2 position, the P2 position and the P position, and the P position and the P4 position are θ, θ2. θ
It is 3. In this example, ■ is the 21st position or the initial position, and at this time, the black color band 5a
is arranged to face the print head 2. During the ribbon shift for color switching during printing operation, the drive gear 18 shifts the total angle θ(
This total angle θ corresponds to the first angle defined in the claims. ) can be rotated back and forth within the range.

Initialization is performed, for example, when power is turned on to the printer. At this time, the drive gear 18 is in one of the positions P1 to P4, but in any position, the drive gear 18 is in the position P in FIG.

rotated clockwise to position. Po position is P
Angle θ from the position. At this Po position, the detection switch SW is shifted clockwise.
It is closed by the pressing piece 181) of No. 8. In addition,
This angle θ. The second claim is defined in the claims.
This corresponds to the angle of .

The drive gear 18 moves from the P position to the P position. In order to keep the transmission lever 21 immobile and the ribbon cassette 3 stationary even when it is displaced to the position or vice versa, in this embodiment the drive gear 18 and the transmission shaft 19 and the transmission shaft 19 and the transmission lever 21 are connected. The clearance at the fitting part is actively utilized in the following manner.

As clearly shown in FIGS. 12 to 15, the shaft hole 18c of the drive gear 18, the transmission shaft 19 and the transmission lever 2
There is always some clearance between the shaft hole 21b of No. 1 and the transmission shaft 19, and this clearance is the play angle β.
, β2 is allowed.

14 and 15 show the drive gear 18 and the transmission shaft 1 in the initial position where the black band 5a faces the print head 2 (the ribbon cassette 3 is located at the lowest position).
9 and the relative positional relationship between the transmission shaft 19 and the transmission lever 21. The driving gear 18 is a biasing spring 2 shown in FIG.
0 in the direction of the half-hour hand, there is play between the drive gear 18 and the transmission shaft 19 as shown in the figure when they are at the initial position shown in FIG. Further, the transmission lever 21 is biased clockwise in FIG. 15 via the guide pin 10e of the switching plate 10 which is biased downward by the spring 12 as shown in FIG.
1 and the transmission Idl 19, there is play as shown in FIG.

Therefore, when the drive gear 18 is rotated clockwise in FIG. 14 via the drive motor 9 for initialization, the transmission shaft 19 rotates following the drive gear 18 from the point where the drive gear 18 has rotated over the angle β. . Thereafter, the transmission shaft 19 is rotated through the angle β or idles through the shaft hole 21b of the transmission lever 19, and the transmission lever 21 remains stationary. The driving gear 18 is at an angle (β + β2) = θ. When the transmission lever 21 has rotated a certain amount, the detection switch SW is closed (solid line state in FIG. 12), but the transmission lever 21 continues to remain stationary. The initialization signal of the detection switch SW at this time is supplied to the control circuit. After opening the detection switch SW, the first
4.The motor 9 is rotated in the reverse direction until the state shown in the figure is reached.

Therefore, for initialization, the drive gear 18 is set to P1.
Upon rotational displacement from the position to the Po position and subsequently back, the transmission lever 21 remains stationary and the ribbon cassette 3 also remains in its lowest position.

It should be noted that the above-mentioned embodiment is merely an illustrative description of a preferred embodiment of the present invention, and various changes can be made without departing from the technical idea of the present invention. For example, the present invention also includes a configuration in which the play angles β and β2 are reduced to zero or close to zero and are transmitted at the time of initialization so that the bar 21 moves.

[Effects of the Invention] According to the multicolor ribbon switching device of the present invention described in detail above, multicolor ribbons can be quickly switched, and the detection switch for detecting the position of the ribbon can be replaced with a normal ribbon. Since it is not opened and closed during shifting, but only during initialization, sufficient durability can be guaranteed. Therefore, it is possible to provide a highly reliable multicolor ribbon switching device with few failures. .

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show a preferred embodiment of the multicolor ribbon switching device according to the present invention, in which FIG. 1 is a reduced plan view, FIG. 2 is a reduced front view, and FIG. 3 is a reduced front view. is a partially sectional left side view showing how it is attached to the printer frame, and Figure 4 is Figure 1 IV-IV.
An enlarged line cross-sectional view, Figure 5 is a back view of the switching plate, and Figure 6 is a
Figure 7 is a cross-sectional view taken along the line X-X of Figure 9, Figure 8 is a cross-sectional view of Figure 7 with the drive gear and transmission lever etc. omitted, Figure 9 is a transmission shaft. FIG. 10 is a cross-sectional view taken along the line X-X in FIG.
Figure 2 is a relationship diagram showing the relationship between the drive gear and the transmission shaft during initialization and the position of the drive gear corresponding to each ribbon shift position, and Figure 13 is a relationship diagram between the transmission lever and the transmission shaft during initialization. , FIG. 14 is a diagram showing the relationship between the drive gear 18 and the transmission shaft at the initial position, and FIG. 15 is a diagram showing the relationship between the transmission lever and the transmission shaft at the initial position. 3...Multicolor ribbon cassette 5...Multicolor ink ribbons 5a to 5d...Color band 9...Drive motor 10...
Switching plate 18... Drive gear 19... Transmission shaft
21...Transmission lever P...Initial position P.・
...Initialization position■ θ...First angle θ1...Second angle β, β2
...More than the play angle due to clearance

Claims (4)

[Claims] (1) A ribbon cassette including a multicolor ribbon in which a plurality of color bands partitioned in parallel in the longitudinal direction are impregnated with ink of different colors, and a ribbon cassette movably supported by a support plate and carrying the ribbon cassette. and a switching plate positioned so that one of the color bands faces the print head, and a drive motor that rotates the plate normally within a first angle range, and rotates the plate beyond the first angle range at the time of initialization. a drive gear rotated to a second angular position; a transmission shaft fitted relatively non-rotatably to the drive gear and rotated; a transmission shaft fitted relatively non-rotatably to the transmission shaft; a transmission lever that is displaced and moves the switching plate; and a transmission lever that is opened and closed by the drive gear when the drive gear is rotated to a second angular position exceeding the first angular range during initialization; A multicolor ribbon switching device comprising: a detection switch that detects a color band of the multicolor ribbon facing the print head at that time; (2) In claim 1, the second angle is substantially equal to the sum of respective play angles caused by clearances at the fitting portions of the drive gear and the transmission shaft, and the transmission shaft and the transmission lever. 1. A multicolor ribbon switching device characterized in that the multicolor ribbon switching device is set to be equal to or slightly smaller. (3) A multicolor ribbon switching device according to claim 1 or 2, characterized in that the drive gear is a sector gear. (4) The multicolor ribbon switching device according to claim 1, wherein the detection switch is attached to an adjustment lever whose rotation can be adjusted around the rotation center of the drive gear.