JPS5917656Y2 - Printer ribbon switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ribbon switching device for a printer, and more particularly to an improved ribbon switching device in which the ribbon does not come into contact with the print head and platen during print color switching.

Various printers are used as input devices for electronic desktop calculators, electronic cash registers, computers, etc.
As this type of printer, printers that can print in multiple colors are well known in order to make it easier to continue recording information, and in normal cases,
Multicolor printing can be obtained by switching and controlling the colors of a ribbon inserted between a print head containing type or dot matrix wire and a platen holding recording paper.

In order to easily change printing colors, the ribbon has two strips in its width direction.
It is divided into parts, and each part is covered with black, red, etc. ink or a plastic coating.

Therefore, when switching print colors, a desired print color can be selected very easily by moving the ribbon in the width direction.

In the printer having the above-mentioned print color switching mechanism,
When switching print colors, the ribbon may come into contact with the print head or platen, causing damage to the ribbon, causing it to sag or coming off, and furthermore, causing stains or color mixing on the recording paper attached to the platen. Ta.

As an improved conventional ribbon switching device, a device has been proposed that retracts the platen from the print head to widen the gap between the platen and the ribbon when switching print colors.

According to this conventional device, when switching print colors, there is no contact between the ribbon and the platen, making it possible to prevent staining or color mixing on the recording paper.

However, this conventional apparatus has the disadvantage that it is not possible to prevent the ribbon from coming into contact with the print head, and the ribbon is easily damaged or sagged.

In particular, in print heads having dot matrix wires, the gap between the print head and the ribbon is small, and the above-mentioned failures occur more frequently.

The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to separate the ribbon from the print head and widen the gap between the two when switching print colors. An object of the present invention is to provide an improved ribbon switching device that can eliminate the drawbacks.

In order to achieve the above object, the present invention includes a ribbon frame that holds the ribbon movably relative to the print head;
a gap expansion mechanism having a first solenoid for moving the ribbon frame in a first direction to widen the gap between the ribbon and the print head; and a gap expansion mechanism having a first solenoid for moving the ribbon frame in a second direction for widthwise movement of the ribbon. The mechanism includes a print color switching mechanism having a second solenoid for moving the print color, and a lock lever for positioning the ribbon frame at a position corresponding to each print color. The ribbon is also retreated from the print head by movement of the ribbon frame.

In the present invention, the operation of the gap expansion mechanism is made to precede the operation of the print color switching mechanism, that is, the ribbon frame is moved by the gap expansion mechanism to separate the ribbon from the print head, and the print color is changed in this state. This prevents contact between the ribbon and the print head.

In the present invention, by causing the gap expanding operation of the platen to precede the gap expanding operation of the lift mechanism, contact between the ribbon and the platen can be reliably prevented.

Preferred embodiments of the present invention will be described below based on the drawings.

1 to 4 show a ribbon switching device in a printer that performs two-color printing using a print head having a dot matrix wire.

The print head 10 has 11 dot matrix wires and is fixedly held on a printer board (not shown).

A platen 12 is pivotally supported on the wire protruding side of the print head 10 in close proximity to the head 10. As shown in FIG. A platen 12 is supported so as to be swingable about a shaft 18 .

A platen swing cam 20 is arranged in contact with the arm 16,
As will be described later, the platen 12 is retracted from the print head 10 by rotating the cam 20, thereby widening the gap therebetween.

A ribbon 22 is inserted between the print head 10 and the platen 12, and by controlling a desired wire of the print head 10 to protrude with recording paper (not shown) in close contact with the platen 12, the ribbon 22 is placed on the recording paper. Ink is printed, and desired dot matrix characters can be formed by sequentially performing the wire projecting action of the print head 10 while scanning the recording paper in the row direction.

Ribbon 22 is wound onto a spool 26.28 which is pivoted on ribbon frame 24 and guided to a position adjacent to print head 10 by guide rollers 30.32 which are pivoted on frame 24.

The ribbon 22 has two widths in its width direction, as shown in FIG.
It is divided into parts, and each divided half has black and red ink attached to it.

The ribbon frame 24 has a bent portion 24 formed at its lower end.
Ear portions 24 b, 24 C are provided at both ends of a, and both eel portions 24 b, 24 C are attached to a moving shaft 34 with a washer 36 .
．． 38.

Therefore, although the ribbon frame 24 is rotatable in the rotational direction with respect to the moving shaft 34, its movement in the axial direction is integrally restricted.

As a result, the ribbon frame 24 can be moved in the axial direction of the moving shaft 34 by the gap expansion mechanism described later to retreat the ribbon 22 from the print head 10, expanding the gap between the print head 10 and the ribbon 22, and Moving axis 3
By tilting the ribbon 22 about the axis 4, the ribbon 22 can be moved in its width direction relative to the print head 10, and the matrix wires of the print head 10 can be made to oppose the different print color portions divided in the width direction.

The gap expansion mechanism includes a first solenoid 42 having a plunger 40 fixed to the moving shaft 34.

The solenoid 42 is fixed to a receiving portion 44 fixed to the printer board, and the aforementioned moving shaft 34 is supported on the receiving portion 44 so as to be movable in the axial direction.

The side wall 44 a of the receiving part 44 and the ear part 2 of the ribbon frame 24
A compression spring 46 is inserted between the ribbon frame 4C and the ribbon frame 24, and as a result, the ribbon frame 24 is always biased toward the left in FIG. 1 by the spring 46.

When the solenoid 42 is energized by the gap expansion signal, the moving shaft 34 and the ribbon frame 24 are activated by the spring 46.
The ribbon 22 moves to the right in FIG.
When the ribbon frame 24 leaves the print head 10, the ribbon frame 24 is released from the locked position of a lock lever, which will be described later.

The printing color switching mechanism is located at the retaining portion 24d of the ribbon frame 24.
a second solenoid 5 having a plunger 48 engaged with the second solenoid 5;
0, and by the suction action of the solenoid 50, it is possible to control the tilting of the ribbon frame 24 about the movement axis 34 shown in FIG.

Due to the tilting of the ribbon frame 24, one of the printed colored portions of the ribbon 22 faces the wire of the print head 10,
The desired print color is selected.

In order to maintain the ribbon position selected by the print color switching mechanism, a lock lever 52 fixed to the printer board is engaged with the ribbon frame 24, and as shown in FIG. lock grooves 52a, 52b
The ribbon frame 24 is held in position to obtain the selected print color.

A biasing spring 54 is engaged with the free end of the ribbon frame 24, and constantly presses and biases the ribbon frame 24 clockwise in FIG.

The embodiment of the present invention has the above configuration, and its operation will be explained below.

1 to 4 show the case where the printing color of the ribbon 22 is red, and the case where the printing color is changed from this state to black will be explained.

The retreating action of the platen 12 is performed prior to the operation of the print color switching mechanism and the gap expansion mechanism.

This platen retraction action is illustrated in FIG. 5, where the approximately 90 degree rotation of the platen and rocker cam 20 causes the arm 16 to rotate counterclockwise about the axis 18, so that the platen 12 moves toward the print head. 10 to facilitate printing color switching, which will be described later.

The gap expansion mechanism solenoid 42 is then energized, causing the ribbon frame 24 to move the ribbon 22 to a retracted position away from the printhead 10.

As a result, the gap between the print head] 0 and the ribbon 22 expands, and the ribbon frame 24 is released from the lock groove 52a of the lock lever 52, as shown in FIG. The frame 24 is rotated about the moving shaft 34 by the tensile force of the spring 54, and moved to the position shown in FIG.

This state is shown in FIGS. 8 and 9, and it can be seen that the black printed color portion of the ribbon 22 faces the wire of the print head 10.

After the printing color switching operation described above is completed, the solenoid 42 of the gap expansion mechanism is de-energized, and as a result, the ribbon frame 24 returns to the state shown in FIG. 1, and as shown in FIG. Lock groove 5
Positioned and held by 2b.

Furthermore, after the gap expansion operation is completed, the platen swing cam 20
is rotated 90 degrees as shown in FIG.
2 returns to the normal printing position.

As described above, the platen retreat, ribbon frame movement, and printing color switching are performed in the correct order, and as a result, the printing color can be quickly switched without the ribbon 22 coming into contact with the print head 10 or the platen 12. be able to.

When switching the printing color from red to black in the above description, the solenoid 50 of the printing color switching mechanism is not energized, and the printing color is switched by the biasing force of the sling 54.

Next, printing color switching from black to red will be explained.

The retreat of the platen 12 and the movement of the ribbon frame 24 are the same as described above, but when switching from black to red, the solenoid 50 is energized by the switching signal after the gap expansion operation is completed.

By energizing the solenoid 54, the ribbon frame 24 is forcibly moved from the state shown in FIG. 7 to the state shown in FIG. 6 against the urging force of the spring 54, and the ribbon frame 24 is moved as shown in FIG.
The relative relationship between the print head 10 and the print head 10 can be obtained.

At this time, the ribbon frame 24 is connected to the first solenoid 42.
Since the lock lever 52 is disengaged from each of the lock grooves 52a and 52b by the gap expansion operation, the ribbon frame 24 and the lock lever do not come into conflict with each other.

As described above, the excitation force of the solenoid 50 causes the ribbon frame 24 to move to the first position facing the lock groove 52a.
The excitation of the solenoid 42 is cut off, and the ribbon frame 24
is engaged and locked in the lock groove 52a as shown in FIG.

As described above, since the print color is switched with the gap between the print head 10 and the platen 12 being expanded, and the gap between the print head 10 and the ribbon 22 being also widened, the print color can be switched extremely easily. I can do it.

As explained above, according to the present invention, it is possible to reliably prevent contact and engagement between the ribbon and other members when switching print colors, and prevent damage to the ribbon, staining of recording paper, and other malfunctions. A ribbon switching device suitable for various printers can be provided.

[Brief explanation of the drawing]

FIG. 1 is a front view of main parts showing a preferred embodiment of the ribbon switching device according to the present invention, FIG. 2 is a side view showing the ribbon frame and print color switching mechanism as seen from the II force direction in FIG. 3 is a schematic explanatory diagram showing the swinging mechanism of the platen in FIG. 1;
4 is a plan view showing the relationship between the ribbon frame and the lock lever as seen from the VI force direction in FIG. 2; FIG. 5 is an action explanatory diagram similar to FIG. Fig. 6 is similar to Fig. 4, but is an explanatory diagram showing the state in which the ribbon frame is released from the lock lever, Fig. 7 is an explanatory diagram showing the state in which the ribbon frame is moved by the printing color switching mechanism, and Fig. 8 is an explanatory diagram showing the state in which the ribbon frame is moved by the print color switching mechanism. 9 is a side view similar to FIG. 2 but showing a state in which the ribbon frame is tilted; FIG.
9 is a plan view showing the relationship between the ribbon frame and the lock lever in FIG. 9, and FIG. 11 is an explanatory view showing the platen position when ribbon switching is completed in FIG. 9.

Claims (3)

[Scope of utility model registration request] (1) A ribbon switching device for a printer that has a print head and a platen in which the gap between the print head expands when switching ribbons, which includes a ribbon frame that holds the ribbon movably relative to the print head, and the ribbon and the print head. First place the ribbon frame to extend the gap between
a gap expanding mechanism having a first solenoid that moves the ribbon frame in a second direction to move the ribbon in the width direction; a print color switching mechanism having a second solenoid that moves the ribbon frame in a second direction to move the ribbon in the width direction; A printer ribbon switching device including a lock lever for positioning a position corresponding to each print color. (2) Utility model registration Claim (1) In the apparatus described in claim (1), contact between the ribbon and the print head is prevented by the gap expansion operation of the gap expansion mechanism preceding the operation of the print color switching mechanism. Features printer ribbon switching device. (3) Utility model registration The device according to claim (2) is characterized in that the gap expanding operation of the platen precedes the gap expanding operation of the gap expanding mechanism, thereby preventing contact between the ribbon and the platen. Ribbon switching device for printers.