JPS5917645Y2 - printer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a type of printer that prints on print paper using type or dot wire via an ink ribbon, and in particular, after automatically correcting the slack of the ink ribbon that occurs when changing the ink ribbon. , provides an ink ribbon switching mechanism for performing printing operations.

FIG. 1 is a partially sectional side view showing a wire dot type impact printing mechanism, and FIGS. 2 to 4 are views showing its ink ribbon feeding mechanism.

A printing paper 2 is supported on a platen 1, and a feed screw 3 and a guide rod 4 are provided parallel to the platen 1.

A carrier 5 is screwed into the feed screw 3, and the feed screw 3
By the rotation of the carrier 5, the carrier 5 is reciprocated along the guide rod 4 in parallel with the platen 1.

A slider 8 is attached to the carrier 5 via two links 6.7 of the same length, forming a four-bar linkage mechanism.

A print head 9 and a wire stroke holding roller 10 are attached to this slider 8, and the two are integrated.
It is hollowed out so that it can move back and forth in the direction of the platen 1 with respect to the carrier 5.

The slider 8 is pulled toward the platen 1 by a coil spring 11, so that the roller 10 is pressed against the platen 1 via the paper 2.

Therefore, even if the number of sheets increases or decreases, the roller 10 contacts the topmost sheet of paper, and the print head 9 follows this roller 10 and is displaced integrally.

Therefore, the gap G between the printing paper and the tip of the print head
is kept constant, and the stroke of the printing wire is constant.

Reference numeral 12 denotes an ink ribbon force cartridge, which has an internal structure as shown in FIG.

The ink ribbon 13a stored in the storage chamber 12a is drawn in through the tip of the print head by rollers 14 and pinch rollers 15, and is supplied to the printing section at the tip.

That is, the ink ribbon is exposed as 13b at the printing section, and is fed through the small gap between the paper 2 on the platen and the tip of the print head 9.

The cost of this ribbon feeding is reduced by utilizing the movement of the carrier as a drive source as described below without providing a special ribbon feeding motor.

FIG. 3 is a view of the inside of the ribbon feed cartridge 12 seen from the back, and shows the ribbon feed roller 1 inside the cartridge.
4, two one-way clutches C1 and C are connected via the shaft 16.
2 are directly connected.

FIG. 4A is a horizontal sectional view of the upper one-way clutch C1, and the opening of the figure is a horizontal sectional view of the lower one-way clutch C2.

Ropes 17 and 18 are stretched parallel to the platen 1, and both ends are fixed to the main body of the apparatus.

Both ropes 17 and 18 are wound around one-way clutches C1 and C2 in the middle.

As shown in FIG. 1, the cartridge 12 is attached to the slider 8, and when the carrier 5 is sent toward the space by the feed screw 3, the cartridge 12 is naturally transferred together with the carrier 5.

Therefore, when the cartridge 12 moves, the one-way clutches C1 and C2 also move, and since the ropes 17 and 18 are wrapped around both clutches C1 and C2, the outer rings 19 and 20 of both clutches C and C2 rotate. do.

At this time, the ropes 17 and 18 are wound in opposite directions so that the outer rings 19 and 20 rotate in opposite directions.

As shown in FIG.
A ball 22 is built in a triangular chamber 21 formed inside the shaft 16', and when the outer ring 19.20 rotates clockwise, the ball 22 pushed by a spring 23 collides with the outer wall of the shaft 16' and the triangular chamber 21. The shaft 16' is inserted between the slopes of the shaft 16' to transmit clockwise rotational force to the shaft 16'.

When the outer rings 19 and 20 rotate counterclockwise, the balls 22
cannot bite into the slope of the triangular chamber 21, so the outer ring idles and cannot transmit rotational force to the shaft 16'.

Therefore, if the carrier moves rightward as shown by the solid arrow in FIG. 4, the clutch shaft 16' also moves rightward via the roller shaft 16 for feeding the ribbon of the cartridge.

As a result, the outer ring 19 of the upper clutch C1 rotates counterclockwise, no rotational force is transmitted to the shafts 16', 16, and the outer ring 20 of the lower clutch C1 rotates clockwise, causing the shaft 16 to rotate clockwise.
', Rotate 16 clockwise.

Conversely, if the carrier moves to the left as shown by the dashed arrow,
The outer ring 19 of the upper clutch C1 rotates clockwise,
The shafts 16', 16 are rotated clockwise, the outer ring 20 of the lower clutch C2 is idled counterclockwise, and the shafts 16', 16 are rotated clockwise.
No rotational force is transmitted to 16.

After all, when the carrier 5 and the cartridge 12 move rightward, the shaft 16' is moved by the lower one-way clutch C2.
16 is driven clockwise and the carrier 5 and cartridge 12 move leftward, the upper clutch C1 drives the shafts 16', 16 clockwise.

Therefore, regardless of whether the carrier moves left or right, the shaft 16 is always driven in a fixed direction, and the ribbon feed roller 14
The ribbon 13b is retracted and a new ribbon in the storage chamber 12a is fed to the print head tip.

12b is a leaf spring for applying tension to the ink ribbon 13b.

In this way, the drive source for the ribbon feed roller 14 is obtained by utilizing the fact that the ink cartridge 12 is moved together with the carrier during the printing operation, so the cost is lower than when a special ribbon feed motor is provided. It becomes easier to go down.

However, the disadvantage is that the ribbon is not fed unless the carrier moves, so the ribbon may remain slack after changing ribbon colors, which may interfere with the operation of the printing element or make it difficult to change printing colors. be.

That is, as shown in FIG. 1, the ribbon 13b has, for example, a lower half 13b1 in black and an upper half 13b2 in red, and color selection during printing is performed by an electromagnet 24.

The rear part of the IJ edge 12 is rotatably supported by a shaft 25, and is normally pushed up to the position shown by the chain line by a spring 26, so that the black part 13b1 of the lower half of the ink ribbon is at the tip of the print head 9. It is supposed to be located.

When the electromagnet 24 is energized and the cartridge 12 is pulled down to the solid line position by the iron core 27 against the spring 26, the red portion 13b2 of the upper half of the ink ribbon descends to the print head tip position.

Switching from the red portion 13b2 to the black portion 13b1 is performed by de-energizing the electromagnet 24 and pushing up the cartridge 12 with the spring 26.

In this way, the printing color is changed by moving the cartridge 12 up and down, but as described in FIG.
Since the ribbon 13b is under tension to prevent it from sagging, the ribbon 13b is always attached to the tip of the print head.

In this way, the ink ribbon cartridge 12 is shifted up and down with the ribbon 13b stuck to the tip of the print head, so even if the cartridge 12 is moved to its normal position, the ink ribbon 13b is stuck to the tip of the print head due to friction. It often remains attached and is not moved to its normal position.

For this reason, the printing color may not be switched accurately and the normal operation of the printing element may be hindered.

Therefore, the present invention improves the conventional printing device in which the ink ribbon is fed by using the movement of the carrier, so that after switching the ink ribbon, the ribbon feed roller is driven to pull the ribbon in the printing section. This is to ensure that the ribbon is set in the correct position and the printing operation is performed, and that the ribbon is pulled after switching so as not to impair the advantages of the printing device, which uses carrier movement to feed the ink. The driving source for applying force also does not use a motor, but effectively utilizes carrier movement.

In order to achieve this objective, the present invention adopts a control method in which the ink ribbon cartridge is switched based on a ribbon switching signal, or the carrier is reciprocated by the same distance following the switching operation. .

Next, details of the present invention will be explained based on illustrated embodiments.

FIG. 5 is a plan view of a printing device for explaining the ink ribbon switching operation according to the present invention, and FIG. 6 is a block diagram of a control circuit for performing the ink ribbon switching operation.

M is a carrier transport motor, and when the feed screw 3 is rotated by the motor M and the carrier 5 is transported, a print element in the print head 9, such as a dot wire, is driven in synchronization with the print information, and the print head 9 is printed. will be held.

Along with the serial operation of the print head 9, the ribbon feed roller in the cartridge 12 is constantly driven in the ribbon feed direction by the one-way clutches CI and C2, and a new ink ribbon 13b is fed to the printing section and used for printing.

When the electromagnet 24 is controlled by the ink ribbon switching signal and the cartridge 12 is switched, the carrier 5 is moved to either the left or the right without printing operation, together with or following the switching operation of the cartridge 12.
It is sent by a pitch, and then sent in the opposite direction again by N pitches and returned to its original position.

Ribbon feeding is performed by this reciprocating movement of the carrier,
Since the ink ribbon 13b is pulled tightly by the ribbon feed roller 14, the misalignment of the ribbon at the time of switching the ink ribbon is corrected and the ribbon is set to its normal position.

The printing operation after ribbon switching is started only after this ribbon position correction operation is completed.

In FIG. 6, reference numeral 28 denotes a drive circuit for the electromagnet 24 for switching the ribbon cartridge.The electromagnet 24 is controlled via the drive circuit 28 in response to an ink ribbon switching signal, and color selection of the ink ribbon is performed.

Reference numeral 29 denotes a drive circuit for the carrier transport motor, which is controlled directly by the ink ribbon switching signal or by the output of the electromagnet drive circuit 28 as shown by the broken line.

Reference numeral 30 denotes a control circuit for the motor drive circuit 29, which sets the rotation direction and rotation angle of the motor M and causes the motor to reciprocate by the same angle.

Therefore, when an ink ribbon switching signal is directly or indirectly input to the control circuit 30, the motor M is rotated, for example, in the forward direction by N pitches, and then rotated in the opposite direction by the same N pitches, as set in advance. A signal is output to the motor drive circuit 29 to cause the motor M to reciprocate by N pitches.

The timing of reciprocating this motor and the timing of driving the electromagnet are set so that after the ribbon cartridge 12 is switched up and down by the operation of the electromagnet 24, the ink ribbon 13b at the tip of the print head is pulled. good.

However, at least as long as the vertical switching operation of the ribbon cartridge 12 is completed before the ribbon feeding operation by the motor is completed, there is no problem even if both operations are performed in parallel.

As described above, according to the present invention, the carrier drive motor is driven back and forth at the same pitch based on the ink ribbon switching signal, and this drives the ink ribbon feed roller to feed the ribbon and apply tension to the ink ribbon. It will be done.

Therefore, even if only the ink ribbon gets caught in the print head section or the like during the ink ribbon switching operation, it can be reliably moved to the correct position, and printing colors can be switched accurately.

Furthermore, since the ink ribbon is always in close contact with the tip of the print head during the printing operation, there is no risk of interfering with the printing operation.

In particular, according to the present invention, tension can be applied to the ink ribbon by using carrier movement directly as a drive source for ribbon feeding, so there is no need to provide a drive source such as a motor, and ribbon feeding during printing operation is possible. Coupled with the fact that this is performed using carrier movement, the cost of the device can be reduced.

Moreover, since both the reciprocating motion of the carrier is effectively converted into a ribbon feeding motion by the one-way clutch, the carrier movement distance for correcting the ribbon position is only a short distance, and the time required for correcting the ribbon position is short.

Although the case in which a ribbon cartridge is used has been described, the present invention is not limited to the cartridge type; it is also possible to implement an open reel type and drive the ribbon take-up reel via a directional clutch.

[Brief explanation of the drawing]

Figures 1 to 4 illustrate conventional printers.
Fig. 1 is a partially sectional side view of the wire dot type printing mechanism, Fig. 2 is a horizontal sectional view of the ink ribbon feeding section, Fig. 3 is a partially sectional rear view of the ink ribbon feeding section, and Fig. 4 is a partial sectional side view of the ink ribbon feeding section. FIG. 5 is a horizontal sectional view of the clutch, FIG. 5 is a plan view of a printing device embodying the present invention, and FIG. 6 is a block diagram showing a control circuit of the ink ribbon position correction mechanism according to the present invention. In the figure, 1 is a platen, 2 is a printing paper, 5 is a carrier, 9 is a print head, 12 is an ink ribbon cartridge, 13 b is an ink ribbon, 14 is a ribbon feed roller,
24 is an electromagnet, 28 is an electromagnet drive circuit, M is a carrier feed motor, 29 is a motor drive circuit, and 30 is a motor control circuit.

Claims (1)

[Claims for Utility Model Registration] A mechanism for feeding an ink ribbon interposed between a print head and a print medium in a fixed direction using the movement of a carrier for transporting the print head as a driving source, and a multi-colored ink that is color-coded. A printer that has a ribbon switching mechanism for moving the ribbon up and down in front of a print head, and a drive means for the ribbon switching mechanism, and switches the color of the ink ribbon by operating the drive means based on an ink ribbon switching signal, The circuit structure is such that the ink ribbon switching signal is input to a carrier drive source in addition to the above-mentioned drive means, and when the ink ribbon switching signal is input to the carrier drive source, the carrier drive source drives the carrier. A printer characterized in that it is equipped with a control circuit that causes the ribbon to reciprocate by an appropriate distance and to feed the ribbon by the specified length.