JPH0588200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a home position detection device for a color ink ribbon in a printer in which a color ink ribbon cassette is mounted on a carriage.

(Prior art) A color ink ribbon (generally four colors [yellow, cyan, magenta, black] or three colors [yellow, cyan, magenta]) is mounted on a cartridge, and the ribbon is shifted up and down to print the color. In conventional printers that are printing, as a means to return the color ink ribbon to the home position (generally black),
When the color ink ribbon is moved up and down when the printer is turned on and a preset color reaches the needle of the print head, a dedicated ribbon position detector is turned on or off. As the dedicated ribbon position detector, a transmissive photo interrupter, a reflective photo interrupter, a micro switch, etc. are used, and are either mounted on the carriage or fixed to the printer body outside the carriage.

(Problems to be Solved by the Invention) By the way, the above-mentioned conventional technology uses a dedicated detector, which increases the cost, and requires wiring for connection to the main board of the detector, which increases assembly man-hours. There is a problem with becoming.

(Means for Solving the Problems) The present invention has been made in view of the above problems, and includes a color ink ribbon cassette mounted on a carriage so as to be movable up and down, and detecting when the carriage is at a specific position within its movement range. A home position sensor is installed on the base frame of the printer to
A sensor actuating plate is attached to the carriage that moves in conjunction with the vertical movement of the color ink ribbon cassette, and when a specific color of the color ink ribbon is placed at the needle position of the print head, the sensor actuating plate moves to the home position of the carriage. The present invention is characterized in that a position detection sensor is activated.

Hereinafter, a detailed explanation will be given based on the illustrated embodiment. 1 is a guide bar 2 arranged parallel to the main body
This is a carriage that slides along lines a and 2b. 3
1 is a lift cam disposed at the center of the upper surface of the carriage 1 so as to be able to rotate in one direction. A cam 4 is integrally formed along the outer circumference in a stepped manner, and four claws 5a, 5b, 5c, and 5d are provided at the lower end. It is divided into equal parts on the circumference and protrudes radially. Switching levers 6a, 6b are protruded from both sides of the carriage 1, and long grooves 6a', 6
b' slides along pins 7a, 7b on the carriage 1 in the sliding direction of the carriage 1, and the inner tips of the switching levers 6a, 6b are connected to the claws 5a, 5b,
5c and 5d are engaged and pressed. 8
Reference numerals a and 8b are springs that always urge the switching levers 6a and 6b toward the outer position. Reference numeral 9 denotes a ribbon holder, which carries a cassette 11 containing color ink ribbons 10 in which ink ribbons of four colors of yellow, cyan, magenta, and black are arranged side by side.
Insert pins 9a and 9b on both sides into holes 12a' and 12b' of 2b.
It is fitted so that it can swing up and down. Reference numeral 13 denotes a lift lever that is vertically movably fitted into a guide 14 that projects perpendicularly to the top surface of the carriage 1. The guide 13a holds the step-shaped cam 4, and the ribbon holder 9 is inserted into the groove 13b.
The pin 9b on the lower surface is fitted. Stoppers 15a and 15b are provided for pressing and sliding the switching levers 6a and 6b when the carriage 1 reaches a position beyond the printing area. Reference numeral 16 indicates a carriage and color ribbon home position detection sensor mounted on the base of the printer body, and reference numeral 17 indicates a color ribbon home position detection sensor 16 mounted on the lift lever 13.
This is a shielding plate. Shielding plates 18 and 19 are fixed to the carriage 1 at regular intervals on both sides of the shielding plate 17.

Next, the effect will be explained. When the carriage 1 moves beyond the normal printing area to the right in the state shown in FIG. 5, the right switching lever 6b is moved as shown in FIG.
contacts the stopper 15b. The lift cam 3 is positioned and held by the load of an index spring (not shown). When the carriage 1 further moves to the right as shown in FIG. 7, the switching lever 6b moves to the left against the spring force of the spring 8b. At that time, it is slid and guided by the pin 7b on the carriage 1, the elongated hole 6b' of the switching lever 6b, the pin 6b'' of the switching lever 6b, and the cam 20b of the carriage 1, and pushes the claw 5a of the lift cam 3 to move the lift cam 3 by 1/4 The index spring holds the lift cam 3 stronger than the springs 8a and 8b.

Next, when the carriage 1 moves to the left and the switching lever 6b moves away from the stopper 15b as shown in FIG. 8, the switching lever 6b returns to its original state by the action of the spring 8b. At this time, the tip of the switching lever 6b passes over the claw 5b, and the pin 6b'' moves downward along the cam 20b, and is regulated by the pin 7b and the elongated hole 6b' and returns to the original position shown in FIG. 5. Action 2
If the lift cam 3 is rotated once, the lift cam 3 will rotate 1/2, if it is rotated three times, it will rotate 3/4, and if it is rotated four times, the lift cam 3 will rotate once. Every time the lift cam 3 rotates 1/4, the cam 4 moves the lift lever 13.
The guide 13a is raised to positions a, b, c, and d in FIG. 9, and the lift lever 13 is moved up and down to shift the cassette 11 housed in the ribbon holder 9 to four stages.

In this embodiment, depending on the stepwise cam deviation position of the lift cam 3, a...black, b...cyan, c...
magenta, d...yellow. Other combinations are also possible. The number of rotations of the lift cam 3 is controlled according to the selected color of the required color ink ribbon 10 by sending a signal so that a predetermined color ink ribbon can be selected. When the carriage 1 moves to the left, the switching lever 6b is returned to its original position by the spring 8b. The shield plate 17 moves up and down together with the lift lever 13, and the shield plates 18 and 19 on both sides of it move left and right together with the carriage 1, but do not move up and down.

Next, the effect will be explained.

A When the power is turned on, when the carriage 1 is not in the home position as shown in FIG. 10 and the home position detection sensor 16 is not blocked by the shielding plates 17, 18, and 19, the carriage 1 moves from right to left, Carriage 1
The left end surface 18a of the shielding plate 18 that is integrally formed with
The time when the carriage 1 crosses the home position detection sensor 16 (transmissive photo interrupter in this embodiment) is the home position of the carriage 1. From this position, the carriage 1 is slowed down and the shielding plate 19 moves to the home position. The carriage 1 is designed to stop when it comes to the position of the movement detection sensor 16.

B. When the power is turned on, the carriage 1 is in the home position as shown in FIG.
When the home position detection sensor 16 is not obstructed, the carriage 1 moves once from left to right by a predetermined distance to bring the home position detection sensor 16 into the state shown in FIG. 11b where it is not obstructed, and then performs the operation A above.

C. When the power is turned on, the carriage 1 is connected to the slit between the shielding plates 17, 18 or 17, 19 and the home position detection sensor 16, as shown in FIG. 12a.
When the two are in opposing positions, the carriage 1 moves from right to left. As a result of this movement, the home position detection sensor 16 immediately (within the time period during which the carriage motor is driven by a predetermined number of steps) closes the shielding plate 17 or 19 as shown in FIG. 12b.
Since this is detected, the carriage 1 is stopped and moves as described in B above.

As mentioned above, the shielding plate 17 is linked to the vertical movement of the color ink ribbon, so when a certain color (for example, black) is placed at the needle position of the print head, the shielding plate 17 activates the home position detection sensor 16. Set it so that it crosses.

As mentioned above, when the power is turned on, the carriage 1 selects A, B, or C to determine its home position.
At this time, the left end surface 1 of the shielding plate 18 is
8a crosses the home position detection sensor 16, the carriage 1 is slowed down, and the home position detection sensor 16 reaches the 10th position before the shield plate 19 stops at the position of the home position detection sensor 16. When the slit portions 20 and 21 shown in the figure are detected twice, it is determined that the color ink ribbon is at its home position, and when the slit portion 22 is detected only once as shown in FIG. It is determined that the ribbon is not at its home position, and the ribbon lifting operation described above is repeated several times, and when the slits 20 and 21 are detected twice, the color ink ribbon is set at its home position. I judge that.

As the color ribbon switching mechanism, in addition to one using carriage control by a carriage motor as in this embodiment, it is also applicable to one using a dedicated drive source such as a motor or solenoid for color ribbon switching. Also, as a color ribbon switching mechanism, instead of swinging the ribbon cassette by the movement of the lift cam, it follows the movement of the lift cam, for example, via a parallel link or as shown in FIG.
Rails formed vertically and parallel to each other integrally with the carriage are used as color ribbon cassette lift guides via cassette guide pins, and the cassette is moved parallel to the carriage base by following the lift cam (aligning the wire arrangement surface at the tip of the printing head with the ink ribbon). It may also be a mode in which it is lifted in the vertical direction while maintaining a constant spacing.

In this embodiment, the home position detection sensor 16
Although it is a transmission type photo interrupter, it can also be used as a reflective type photo interrupter, magnetic sensor,
It goes without saying that a detector such as a microswitch can be used, and that the slits in the shielding plates 17, 18, and 19 can be detected in many combinations.

In the case of this embodiment, the color ribbon is formed on a part of the lift lever for detecting the home position.
In this example, the function is performed through a shielding plate that protrudes downward from the carriage, but in conjunction with the above combination modification, the function of the shielding plate is performed through the movement of a color ribbon cassette that moves up and down by the drive of a ribbon switching mechanism. Any mechanism for this purpose may be formed directly on the cassette, and these combinations and modifications do not change the gist of the present invention.

(Effects) According to the present invention, a color ink ribbon cassette is mounted on the carriage so as to be movable up and down, and a home position sensor for detecting when the carriage is at a specific position within the movement range is disposed on the base frame of the printer. A sensor activation plate is installed that moves in conjunction with the vertical movement of the color ink ribbon cassette, and when a specific color of the color ink ribbon is placed at the needle position of the print head,
Since the sensor operating plate operates the home position detection sensor of the carriage, the color ink ribbon can be detected by the home position detection sensor of the carriage without using a dedicated color ink ribbon home position detection sensor. Since it also serves as home position detection, costs can be reduced.

In addition, the connection wiring process with the main board is no different from the conventional method, and unnecessary man-hours can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an embodiment of the present invention, Fig. 2 is a left side view of Fig. 1, Fig. 3 is a front view of the main part of Fig. 1,
FIG. 4 is a perspective view of FIG. 3, FIGS. 5 to 8 are plan views explaining the operation of the lift cam, FIG. 9 is an explanatory diagram showing shifting of the lift lever guide in four stages, and FIG.
12 are explanatory diagrams of the operation when the shielding plate 17 crosses the home position detection sensor, FIG. 13 is an explanatory diagram of the operation when the shielding plate 17 is not crossed, and FIG. 14 is another embodiment of the color ribbon switching mechanism. It is an operation explanatory diagram. 1...Carriage, 3...Lift cam, 4...
Cam, 5a, 5b, 5c, 5d...Claw, 6a, 6
b...Switching lever, 8a, 8b...Spring, 9...
Ribbon holder, 10...Color ink ribbon,
11...cassette, 13...lift lever, 13
a...Guide, 13b...Groove, 15a, 15b...
...stopper, 17...shielding plate attached to the lift lever, 18, 19... blocking plate attached to the carriage, 20, 21, 22... gap between the blocking plates.

Claims (1)

[Claims] 1. A color ink ribbon cassette is mounted on the carriage so that it can move up and down, and a home position sensor is installed on the base frame of the printer to detect when the carriage is at a specific position within the moving range.
A sensor actuating plate is attached to the carriage that moves in conjunction with the vertical movement of the color ink ribbon cassette, and when a specific color of the color ink ribbon is placed at the needle position of the print head, the sensor actuating plate moves to the home position of the carriage. A device for detecting a home position of a color ink ribbon in a printer, which operates a position detection sensor.