JPH0712025Y2 - Day tent mechanism for printer ribbon selection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is to move a ribbon, which is divided into a plurality of color tracks in a width direction in a printer, in the width direction in accordance with print contents to obtain a target color track. The present invention relates to a ribbon selection detent mechanism for a printer that holds a ribbon at a selection position when selecting.

[Conventional technology]

Generally, a printer using a ribbon cassette is widely used as an output mechanism of various information devices.

In a printer that performs multicolor printing, a ribbon that is divided into a plurality of color tracks in the width direction is used.

As a mechanism for selecting and printing a ribbon having a plurality of color tracks in accordance with the color to be printed, the mechanism disclosed in JP-A-59-176084 and JP-A-59-182773 is conventionally used. Is proposed.

In these conventional examples, a carriage on which a print head is mounted is provided so as to be movable in parallel with respect to a platen, and the carriage is moved to the upper ends of side support parts formed by bending and bending at both ends in the moving direction of the carriage. A ribbon cassette mounting table, which is opened upward with a pivot parallel to the direction, is pivotally mounted, and a ribbon cassette having ribbons divided into a plurality of color tracks in the width direction, that is, the vertical direction, is mounted on the ribbon cassette mounting table. Then, a part of the ribbon is made to run between the print head and the platen, and
The ribbon cassette is allowed to swing about the pivot at the same height as the platen, and further, from the output shaft of a stepping motor provided on the carriage to a fan-shaped gear fixed to the ribbon cassette mounting table via a reduction gear train. Forward and reverse rotations are transmitted to drive the ribbon cassette so that the color track of the desired color faces the print head, and the detent mechanism provided at the position closest to the platen of the carriage causes the desired color. The ribbon cassette and the ribbon cassette mounting table are stopped so that the color tracks of (1) face the print head.

[Problems to be solved by the invention]

In the conventional example, since the stepping motor and the gear group for driving the ribbon cassette mounting table and the detent mechanism for holding the ribbon cassette at the selected position are provided separately, there are the following problems. .

That is, when the stepping motor is driven to move the ribbon cassette to the selected position and then the power supply to the stepping motor is stopped, the detent mechanism temporarily tries to hold the ribbon cassette or the like at the selected position. And the like tend to descend due to their own weight, so it was necessary to apply a self-holding current to the stepping motor to prevent the ribbon cassette and the like from descending. Also, the elastic force of the detent spring is increased in order to prevent the ribbon cassette, etc. from descending. However, if this is done, it will cause a great resistance when moving the ribbon cassette, etc. to another selected position, and drive the stepping motor. I had to increase my strength. Further, it is difficult to accurately match the selection stop position by the detent mechanism and the selection stop position by the stepping motor, and the accuracy of ribbon selection is poor in the end, and accurate printing cannot be performed, and further color mixing occurs. There was a problem that it would end up.

The present invention has been made in view of these points, the driving force required for ribbon selection is small, it is not necessary to supply a self-holding current when selection is stopped, and moreover, the ribbon is accurately stopped at the selected position to mix colors. An object of the present invention is to provide a detent mechanism for selecting a ribbon of a printer that can perform good printing without a mark.

[Means for solving problems]

The ribbon selection detent mechanism of the printer of the present invention comprises a ribbon cassette mounting table for mounting a ribbon cassette, in which a ribbon divided into a plurality of color tracks in the width direction is installed, facing the platen. A detent cam provided so as to rotate integrally with a drive gear for width-direction driving of a width-direction drive mechanism that moves in the width direction of the width direction, and when the ribbon is moved to an appropriate selected position by rotation of the drive gear. A detent post that engages with a recess of the detent cam and stops and holds the ribbon at an appropriate selected position, and the detent cam has a rotation direction outer side position than a recess corresponding to the initial position of the ribbon. A stopper is provided which engages with the detent post and prevents the detent cam from rotating outward from the initial position. And it features.

[Action]

In the present invention, by rotating the drive gear of the width direction drive mechanism, the ribbon cassette mounting table and the ribbon cassette are moved in the width direction of the ribbon, and the detent cam rotates integrally with the drive gear. The detent mechanism is always operated in cooperation with the detent post, and when the ribbon moves to an appropriate selected position, the rotation of the drive gear is stopped and at the same time, the detent post engages with the recess of the detent cam. As a result, the ribbon or the like is stopped and held at an appropriate selection position. Since the stopping operation of the ribbon or the like by stopping the rotation of the drive gear and the stop position holding operation by the detent mechanism are performed in synchronization, the selected stop position becomes accurate and accurate printing is performed. To be done.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show the entire ribbon selecting mechanism to which an embodiment of the present invention is applied, and reference numeral 1 in the drawings is a long rotatable platen. On the frame (not shown) of the printer, two guide rods 2 and 3 are laid horizontally in parallel with the platen 1, and a carriage 5 having a print head 4 mounted on these guide rods 2 and 3 reciprocates. It is slidably mounted. Above the carriage 5, a ribbon cassette mounting table 7 on which the ribbon cassette 6 is mounted is supported via a pair of supporting arms 8 and width-direction driving mechanisms 9 provided at both ends of the carriage 5 in the moving direction. ing. Each one of the support arms 8 is formed in a substantially U-shape, and is located at the rear portion of the carriage 5 (position far from the platen 1; right side portion in FIG. 1).
Are provided in each. The lower end of each supporting arm 8 is pivotally attached to the carriage 5 by a pivot 10 parallel to the platen 1, and the upper end of the support arm 8 projects toward the lower surface of the ribbon cassette mounting table 7 by a pivot 11 also parallel to the platen 1. It is pivotally attached to an installed bracket 12. As a result, the ribbon cassette mounting table 7 is supported at its rear part by two pivot points of the pivots 10 and 11, and the platen is supported within the relative movement range of the supporting arm 8 with respect to the carriage 5 and the ribbon cassette mounting table 7 with respect to the supporting arm 8. It is freely movable in a plane orthogonal to the axial direction of 1.

The other width-direction drive mechanism 9 supports the ribbon cassette 6 together with the ribbon cassette mounting table 7 and moves the ribbon cassette mounting table 7 freely movable in one plane with two pivot points in a predetermined direction. This is for moving the ribbon contained in the ribbon cassette 6 in the width direction thereof, that is, relative to the platen 1, and is provided below the ribbon cassette mounting table 7. A mounting stay 13 for providing the width direction drive mechanism 9 is fixed to the carriage 5 with tightening screws 14, 14. A width direction drive plate 15 for driving the ribbon cassette mounting table 7 is reciprocally mounted in a predetermined direction on the mounting stay 13. That is, a long width drive plate
An elongated guide hole 16 is formed in the upper part of 15 and an internal tooth rack 17 is formed in the lower part, and one of the elongated guide holes 16 is engaged with a guide pin 18 projecting from the mounting stay 13 in parallel with the pivot 10. The other inner tooth rack 17 is engaged with a drive gear 20 rotatable about a center shaft 19 projecting from the mounting stay 13 in parallel with the pivot shaft 10 to connect the guide pin 18 and the center shaft 19. It is reciprocally movable along a straight line. The upper end of the width-direction drive plate 15 is hinged via a pin 21 and a bracket 21 protruding from the lower surface of the ribbon cassette mounting table 7. The movement direction of the width direction drive plate 15 is incorporated in the ribbon cassette 6 in relation to the rotation range of the support arm 8 about the pivot axis 10 and the rotation range of the ribbon cassette mounting table 7 about the pivot axis 11. The uppermost and lowermost color tracks of the ribbon are arranged so that they can be moved between the upper and lower positions when they are in proper positions with respect to the platen 1 and the print head 4. The drive gear 20 is provided with a transmission gear 23 that rotates integrally with the drive gear 20. The transmission gear 23 is meshed with the output gear 25 fixed to the output shaft of the stepping motor 24 fixed to the mounting stay 13. Has been. By rotating the stepping motor 24 forward and backward, the drive gear 20 is rotated forward and backward via the output gear 25 and the transmission gear 23, and the width direction drive plate 15 is moved up and down via the internal gear rack 17.

In the present embodiment, the detent mechanism 26, which holds the width-direction driving plate 15 of the width-direction driving mechanism 9 in a stopped state at the position where the color track of the ribbon is selected, is directly related to the width-direction driving mechanism 9. Is provided. That is, a detent cam 27 that rotates coaxially and integrally is provided on the side surface of the transmission gear 23 opposite to the drive gear 20, and the detent plate is provided on the side surface of the mounting stay 13 on the detent cam 27 side.
29 is attached so as to be movable in parallel with the width direction drive plate 15, and upward pressing force is applied to the detent plate 29 by the compression spring 30, and a plurality of detent cams 27 of the detent cam 27 are further provided at the lower end of the detent plate 29. A detent post 31 that engages with the recess 27a is provided in a protruding manner. The detent plate 29 is vertically movable by being loosely fitted with the guide pin 18, the central shaft 19, the long groove 32 and the elongated hole 33. Also, the detent cam 27 has four concave portions when the number of color tracks of the ribbon is four, for example.
27a, 27a ... Are provided according to the size of the center angle of rotation of the drive gear 20 required to move each color track to an appropriate position. The detent post 31 is located at a position further outward in the rotational direction of the recess 27a corresponding to the initial position when one of the color tracks at the top of the ribbon faces the platen 1 and the print head 4. The detent cam 27 is provided with a stopper 34 which is engaged with the detent cam 27 to prevent the detent cam 27 from further rotating.

Further, in this embodiment, the ribbon winding pulley 36 is provided below the ribbon cassette mounting table 7 and near the support arm 8.
Is rotatably attached. As shown in FIG. 2, a wire 37 having both ends fixed to the frame of the printer is wound around the ribbon winding pulley 36 only once, and when the carriage 5 moves, the wire 37 is removed. The ribbon winding pulley 36 that is wound rotates, and the ribbon in the ribbon cassette 6 is wound.

Next, the operation of this embodiment will be described.

When a print command for selecting a specific color track from among the color tracks of the ribbon is issued, a drive pulse for returning the width direction drive plate 15 to the initial position is first issued to the stepping motor 24, and the output gear 25, the transmission. Via the gear 23, the detent cam 27 has its stopper 34 and the detent post 31.
Is rotated in the direction of engagement with (counterclockwise in FIG. 4),
Then, when the stopper 34 engages with the detent post 31 and the stepping motor 24 goes out of step, the stepping motor 24
Is temporarily stopped. As a result, the width direction drive plate 15 is localized at the initial position.

In the present embodiment, initial positioning can be reliably performed by a simple method of stopping energization after stepping motor 24 is stepped out. This eliminates the need for a sensor for initial positioning, and also eliminates the need for indexing the mounting position of the stepping motor 24.

Next, a drive pulse for rotating the central angle from the initial position to the recess 27a of the detent cam 27 corresponding to the color track to be selected is emitted toward the stepping motor 24, and the stepping motor 24 rotates. The rotation is transmitted to the guide pin 18 of the width direction drive plate 15 through the output gear 25, the transmission gear 23 and the drive gear 20, and the width direction drive plate 15 is guided and moved by the guide pin 18 and the central shaft 19. When the color track to be selected on the ribbon reaches the proper position facing the platen 1 and the print head 4,
The power supply to the stepping motor 24 is cut off and the rotation of the stepping motor 24 is stopped.
Even after the detent post 31 of the above is engaged with the selected recess 27a of the detent cam 27 and the power supply to the stepping motor 24 is cut off, the ribbon cassette 6 and the width direction drive plate 15 are prevented from descending due to their own weight. Hold the color track to be selected in place. In this embodiment, since the drive gear 20 and the detent cam 27 are integrally provided, the progress of the width direction drive plate 15 and the detent cam 27 is always synchronized, and therefore the ribbon is accurately Stopped and held in proper selection position. Therefore, good printing without color mixture is performed, and the printing accuracy is very high. Further, since the detent post 31 and the recess 27a of the detent cam 27 engage with each other, the rotation of the detent cam 27 and the lowering of the width direction drive plate 15 are prevented at the same time, and the stepping motor 24 is not energized. Even if they are cut off, they are held stationary. Therefore, it is not necessary to supply the self-holding current to the stepping motor 24, the power consumption is small, and the heat generation amount of the motor is also small.

When the width direction drive plate 15 is moved, the detent cam 27 also rotates clockwise from the initial position in FIG. At that time, when the detent post 31 rides over the intermediate mountain portion of each recess 27a, it rotates while resisting the elastic force of the compression spring 30 pushing the detent plate 29 upward. However, the elasticity of this compression spring 30 is
The value is small enough for the detent post 31 to follow the detent cam 27, and does not become a resistance for the ribbon selective drive operation. Therefore, the driving force of the stepping motor 24 required to drive the ribbon cassette 6 and the like is a very small value, which is the sum of the force for lifting the weight of the ribbon cassette 6 and the elastic force of the compression spring 30.

If the color track to be selected corresponds to the initial position, the width direction drive plate 15 is returned to the initial position and then the color track is selected without energizing the stepping motor 24. .

When the color track to be selected is further changed, it is performed by appropriately combining the above-described returning operation to the initial position and the subsequent selecting operation.

The present invention is not limited to the above embodiment,
It can be changed if necessary.

[Effect of device]

As described above, since the ribbon selection detent mechanism of the printer of the present invention is constructed and operates, the driving force required for ribbon selection is small, it is not necessary to supply the self-holding current when the selection is stopped, and the ribbon is accurately moved. The present invention has an effect that it can be stopped at the selected position to perform good printing without color mixture.

[Brief description of drawings]

The drawings show an embodiment of the ribbon selection detent mechanism of the printer of the present invention. FIG. 1 is a partially cutaway side view of the ribbon selection mechanism to which the present embodiment is applied, and FIG. 2 is a plan view of FIG.
FIG. 3 is a view of the blade in FIG. 1, and FIG. 4 is IV-IV in FIG.
It is sectional drawing which followed the line. 1 ... Platen, 4 ... Print head, 5 ... Carriage, 6 ... Ribbon cassette, 7 ... Ribbon cassette mounting table, 8 ... Bearing arm, 9 ... Width direction drive mechanism, 15 ...
Width direction drive plate, 17 …… Internal tooth rack, 20 …… Drive gear, 24 …… Stepping motor, 26 …… Detent mechanism, 27 …… Detent cam, 29 …… Detent plate, 31 …… Detent post, 36… … Ribbon winding pulley.

Claims (2)

[Scope of utility model registration request] 1. A width for moving a ribbon cassette mounting table, on which a ribbon cassette, in which a ribbon divided into a plurality of color tracks in a width direction is installed, facing in a platen direction, to be mounted, in the ribbon width direction. A detent cam provided on the drive gear for driving the width direction of the directional drive mechanism so as to rotate integrally, and a detent cam in the recess of the detent cam when the ribbon is moved to an appropriate selected position by the rotation of the drive gear. And a detent post that stops and holds the ribbon at an appropriate selected position, and the detent cam engages with the detent post at a position outside the recess corresponding to the initial position of the ribbon in the rotational direction. And a stopper for preventing the detent cam from rotating outwardly from the initial position. Tent mechanism. 2. A range of utility model registration characterized in that the drive gear is rotationally driven by a stepping motor, and energization to the stepping motor is cut off when the detent post is engaged with the recess of the detent cam. A detent mechanism for ribbon selection of the printer according to item 1.