JPS61127384A - Ribbon end detection mechanism - Google Patents

Abstract

PURPOSE:To prevent the complication of the structure of a ribbon end detection mechanism by providing a sensor to detect the end of a ribbon in the face of the opening of a ribbon cassette. CONSTITUTION:An opening 21 for detection of the end of a ribbon is provided in a ribbon cassette 4, and paired reflection type sensors 221 and 222 are also provided. The sensor 221 is provided in the face of the opening 21 of the cassette 4 shifted to printing position corresponding to a printing head 31, and the sensor 222 is on position corresponding to a printing head 32. In this case, since the ribbon cassette out of printing positions is not fed, the detection of ribbon end is not needed. The outputs of the sensors 221 and 222 are effective only when used for printing. Since the ribbon ends of the cassette set in stage can be detected by one sensor in combination with shifting the cassette, the structure can be simplified and the cost can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to printers such as thermal transfer printers, particularly when multicolor printing is performed using a plurality of ribbon cassettes each containing ribbons of different colors. This invention relates to a ribbon end detection mechanism.

In this Yuzu printer, ribbon cassettes are stacked one on top of the other, and printing is performed by positioning a desired ribbon cassette at a predetermined position in the vertical direction (printing position facing the platen). In this case, even if the printing operation continues with the ribbon unwound, printing will not be performed, so it is necessary to detect the end of the ribbon and replace the ribbon cassette.

[Conventional technology]

A conventional ribbon end detection mechanism employs a configuration in which each ribbon cassette is provided with a ribbon end detection sensor.

[Problem that the invention seeks to solve]

However, such a structure in which each ribbon cassette is provided with a sensor has the disadvantage that the structure of the ribbon cassette becomes complicated and the cost increases.

[Failure to solve the problem]

The purpose of the present invention is to provide a ribbon end detection mechanism capable of solving the Q problem described above, and as a means for that purpose, a plurality of ribbon cassettes stacked in the vertical direction are shifted vertically to join. In a printer that positions a ribbon cassette at a printing position and performs printing using the ribbon of the ribbon cassette, the ribbon/cassette is provided with an opening for detecting a ribbon end, and the ribbon cassette is positioned at the printing position. A sensor for detecting the ribbon end of the ribbon cassette is provided at a position facing the opening of the ribbon cassette.

[For production]

Since only the ribbon of the ribbon cassette positioned at a predetermined position (printing position) is fed during printing, and the ribbons of other ribbon cassettes are not fed, one sensor facing the opening of the ribbon cassette at the predetermined position is used. By combining this with the shift of the ribbon cassettes, it is possible to detect the ribbon ends of a plurality of ribbon cassettes.

〔Example〕

The invention will now be described in detail in conjunction with the drawings.

FIG. 1 is a plan view showing the main parts of a thermal transfer printer to which the present invention is applied, and FIG. 2 is a side view of the same. In the figure, 1 is a carrier frame, 2 is a ribbon frame, 3. .

3 is a print head, and 4 is a ribbon cassette.

The carrier 7 frame 1 has a guide portion 6.7 guided by a guide shaft (not shown) along the platen 5,
It can be moved forward and backward while resting on the platen 5.

The ribbon frame 2 is supported by the carrier frame 1 so as to be vertically movable, and is positioned at a predetermined position in the vertical direction by a ribbon shift mechanism 8. The ribbon shift mechanism 8 is connected to the carrier 7 as shown in detail in FIGS.
A pair of glue/glue-shaped members 10 are supported on the frame 1 so as to be swingable about the shaft 9, a shift motor 11 is attached to the carrier frame 1, and the shift motor 11 is used to drive a gear group, etc. This is different from the shift cam 12 which is driven via a drive system. The link-like member 10 is a first shift link 13
and a second shift link 14 that is longer than the shift link 13.
and holes 15 formed at opposing positions of each of the shift links 13 and 14.
As shown in FIG. 5(a), which is a cross-sectional view taken along the line V-V in FIG. A U-shaped plate 16 is attached. Shiftlin.

; Ri 15 has the first pin: #-17, and the shift link 1
4,-- are provided with a second pin 18. The pin 17 passes through the shift link 14 with a space 9 (both links 13 described later).
.

Now, when the shift motor 1 is rotated by a predetermined amount in a predetermined direction from the state shown in FIGS. 2 and 6, the shift cam 12 is rotated by a predetermined amount in the counterclockwise direction as shown in FIGS. The shift link 13, which is engaged through the shift link 13, swings a predetermined amount in the counterclockwise direction in FIG. Along with this, the shift link 14 that engages with the shift link 16 via the plate spring 16 also swings in the same direction, and the shift link 14 and the
The ribbon frame 2 engaged via 8 moves upward.

Then, at the end of the rotation of the shift cam 12, the projecting piece 2b of the ribbon frame 2 is positioned to be locked to the locking part 19α of the stopper 19 provided on the carrier frame 1, and mounted on the ribbon frame 2 in two stages facing each other. The lower two ribbon cassettes 4 of the four ribbon cassettes each contain ribbons of different colors (Y, M, C, BL).
is positioned at the printing position.

After that, the shift cam 12 rotates a little further and stops, but
During this time, the shift link 14 remains stopped, and only the shift link 13 swings while compressing the leaf spring 16, as shown in FIG. 5(b). That is, the rotation of the shift cam 12 during this period is absorbed by the relative movement of both shift links 13 and 14, but this is because the pin 17 through hole of the shift link 14 is made to have a diameter larger than that of the pin 17 as described above. This is possible because it has the following characteristics. When positioning the two upper ribbon cassettes 4 to the printing position, the shift cam 12 is rotated by the same amount in the opposite direction to that described above. In this case, at the end of the rotation of the shift cam 12, the protrusion 2b
is engaged with the engagement portion 19b of the stopper 19, and the upper ribbon cassette 4 is positioned at the printing position. After that, only the shift link 16 swings as the shift cam 12 rotates. Figures 2 and 3 show the state immediately before the completion of this operation. In this way, the cam stroke of the shift cam 12 is determined to be S+α with respect to the shift stroke S of the ribbon frame 2, and this α portion is released by the leaf spring 16,
The ribbon frame 2 is attached to the locking portions 19α, 19 of the stopper 19.
Since the υ position is determined by locking the ribbon cassette to the printing position b, it is possible to secure the shift amount with high accuracy and position the ribbon cassette at the printing position.

The two print heads 3x and 3t are rotatably supported by the carrier frame 1 via shafts 20, respectively. One print head 3. is one upper and lower ribbon cassette 4
The other print head 6 corresponds to the other two upper and lower ribbon cassettes 4. When the carrier frame 1 moves in the direction of arrow A in FIG. 1, the print head 31 comes into pressure contact with the platen 5 via a ribbon and printing paper (not shown) built into the pad 4 for printing. Printing is performed in this state. Although detailed illustrations are omitted, printing is performed by energizing a predetermined heating element at a predetermined time among a plurality of heating elements provided on the surface of the print head 31 facing the platen 5. Figure 2 shows the upper ribbon cassette 4.
This shows a case where the ribbon cassette 4 is used for printing by the print head 3I, and the ribbon contained in the ribbon cassette 4 remains in contact with the printing paper when the carrier claim 1 moves in the direction of the arrow A. That is, during this movement of the carrier frame 1, the ribbon is paid out from the payout side reel of the ribbon cassette 4 at the same speed as the moving speed of the carrier frame 1, and is wound onto the take-up side reel without slack. Although detailed illustration is omitted, this ribbon feeding is performed in conjunction with the movement of the carrier frame 1 in the direction of arrow A.

Ribo/feeding is performed in this way only in the ribbon cassette used for printing (the one facing the platen 5), and not in other ribbon cassettes. Next, when the carrier frame 1 moves in the direction of arrow A', the print head 3. Printing is performed. In this case, the print head 51 is retracted from the platen, and the ribbon is not fed out from the ribbon cassette 4 corresponding to the print head 61.

During these printing processes, the ribbon cassette is shifted (the operation of positioning the ribbon cassette containing a desired color ribbon to a position facing the platen) as needed.

By the way, in the case where the ribbon cassette is mounted on the carrier frame and there is only one print head, printing is performed only when the carrier frame moves in one direction (space operation), and when the carrier frame moves in the opposite direction. Printing is not performed during movement (carrier return operation), which poses a problem in terms of high-speed printing, but in this example, two print heads are provided and a ribbon cassette corresponding to each print head is provided. , high-speed printing becomes possible.

In the present invention, as a ribbon end detection mechanism in a printer having such a configuration 2 effect, each ribbon cassette 4 is provided with an opening 21 (see FIG. 2) for ribbon end detection, and a pair of reflective sensors are provided. 22. , 22
．． has been established. The sensors 221 and 22 are attached to the carrier frame 1 via the bracket 23, and the sensor 228 is attached to the ribbon cassette 4 that has been shifted to the printing position in the ribbon cassette 4 corresponding to the print head 6. Opposed to the opening 21 is a sensor 22 . is arranged to face the opening 21 of the ribbon cassette 4 that has been shifted to the printing position in the ribbon cassette 4 corresponding to the print head 3□.

In this way, the sensor 22. ．． 22. is opposed to the opening 21 of the ribbon/cassette 4 that has been shifted to the printing position, so it is possible to detect the end of the ribbon used at the printing position. In this case, since the ribbon cassette outside the printing position is not fed, there is no need to detect the ribbon end, and the sensor 22. , 22□ are valid only when the ribbon cassette is shifted to the printing position and used for printing.

Figure 6 shows how to detect the ribbon end when 4A, 4B, and 4C are stacked in 6 tiers (ribbon end). When each ribbon cassette is positioned as shown by the solid line,
4A is at the printing position and its ribbon end is detected. Furthermore, when each ribbon cassette is shifted one pitch upward to the position indicated by the chain line, the ribbon cassette 4B is positioned at the printing position and its ribbon end is detected. In this case, six locking parts are provided on the stopper that positions the ribbon frame to be shifted, and the middle locking part is movable and moved forward and backward as necessary to lock the seven ribbon frames (
When positioning the middle ribbon cassette (4E) to the printing position).

〔Effect of the invention〕

As described above, according to the present invention, the ribbon end of a plurality of ribbon cassettes stacked in stages can be detected with a single sensor in combination with a ribbon cassette shift. Furthermore, since there is no need to provide a sensor for each ribbon cassette, the structure can be simplified and costs can be reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory view of the flat part action showing the sandwich part of a thermal transfer printer to which the present invention is applied;
FIG. 6 is an explanatory diagram of the ribbon detection procedure. In the figure, 1 is a carrier frame, 2 is a ribbon frame, 3
．． , 3. is a print head, 4, 4A, 4B, 4C are ribbon cassettes, 5 is a platen, 8 is a ribbon shift mechanism, 2
1 is an opening, and 22+ and 22t are sensors.

Claims (1)

[Claims] In a printer that performs printing by shifting a plurality of ribbon cassettes stacked in the vertical direction and positioning a desired ribbon cassette at a printing position, the ribbon cassette is provided with an opening for detecting a ribbon end, and A ribbon end detection mechanism, characterized in that a sensor for detecting the end of a ribbon contained in the ribbon cassette is provided at a position opposite to the opening of the ribbon cassette positioned at the printing position.