JPH06210881A - Print unit for printers - Google Patents

Abstract

PURPOSE:To provide a print head for a printer of a cassette exchange type, which is compact and simple in construction. CONSTITUTION:Provided on a main frame 9 are shafts 17a, 17b serving as guides, on which shafts are provided pawl rings 15a, 15b including a pawl 16 adapted to be driven by a motor 10. Provided on a plate 32 is a plate 21 adapted to be biased downward by a spring, on which plate 21 is rubber rings 20, 20 for sucking and discharging a ribbon cassette which is driven by a motor 22. A thermal head 29 is vertically movably provided on a plate 23, and a motor 26 is provided for vertically moving the thermal head 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing unit of a thermal transfer printer, and more particularly to a printing unit of a printer for printing while automatically changing a ribbon cassette.

[0002]

2. Description of the Related Art In a conventional color printer, a method of making a composite color by using an ink ribbon in which four colors of inks of yellow, magenta, cyan and black are sequentially applied to one ribbon is widely used. The printing unit did not need to automatically change cassettes or identify cassettes.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a printing unit which realizes a cassette exchange type thermal transfer printer.

[0004]

The present invention has been made to solve the above problems, and a first invention is a thermal head, and means for pressing and retracting the thermal head.
The ribbon cassette is provided with a means for sucking and discharging the ribbon cassette, a means for guiding and holding the ribbon cassette, and a means for winding the ribbon. A second aspect of the present invention is the basic configuration according to the first aspect of the present invention, further including means for restricting the position of the ribbon cassette by a member that interlocks with the thermal head when the thermal head is pressed.

A third aspect of the invention further comprises means for detecting the suction position of the ribbon cassette, in addition to the structure according to the first or second aspect of the invention, and the fourth aspect of the invention is the first or the second aspect of the invention. The invention of claim 3 is provided with a detection means of a plurality of bits for separating individual ribbon cassettes.
In addition to the first to third inventions, ribbon cassette identification means which also serves as ribbon cassette position detection means is further provided.

[0006]

1 is a perspective view of a color printer equipped with a printing unit according to the present invention, and FIG. 2 is an internal structure of the printing unit according to the present invention. FIG. 3 is a perspective view of a ribbon cassette used in the printing unit according to the present invention, and FIG. 4 is an explanatory diagram showing a positional relationship between the ink ribbon cassette and the print head during printing.

In FIG. 1, the printing unit 1 is attached to a carrier plate 2, and the carrier plate 2
Is connected to the feed screw 3 and the guide mechanism 2a, and can be moved left and right by rotating the feed screw 3. Four
a is a ribbon cassette mounted in the printing unit 1, 5 is a paper feed roller, 6 is a platen, and 7 is a ribbon having a function of storing a plurality of ribbon cassettes and pushing out and pulling the ribbon cassettes. The storage units 4b are ribbon cassettes stored in the ribbon storage unit 7.

(Ribbon Winding Mechanism) FIG. 2 shows the internal structure of the printing unit according to the present invention.
A ribbon winding mechanism is provided in the. That is, the rotation of the motor 10 is transmitted to the gear 12 via the intermediate gear 11, the gear 12 is rotatably attached to the shaft 13a, and the rotation of the gear 12 is transmitted to the claw ring 15a via the friction mechanism 14a. The tab 16 is provided on the claw ring 15a, and when the ribbon cassette is loaded, the claw ring 15a is fitted with the claw ring of the ribbon cassette to wind the ribbon.

Similarly, the other ring 13b is also provided with the nail ring 15.
Although the b friction mechanism 14b is fitted, one end of the friction mechanism 14b is directly attached to the frame 9, and the friction torque of the friction mechanism becomes the torque required to rotate the claw ring 15b. The friction torque of the friction mechanism 14a is the same as the friction mechanism 14b.
Is sufficiently larger than the friction torque of. The friction mechanism 14a is for responding to changes in the ribbon winding diameter, and the friction mechanism 14b is for giving the ribbon a tension for eliminating slack of the ribbon on the set side.

(Cassette Guide and Holding) The cassette guide for sucking and discharging the cassette has a shaft 17a17b as a main guide, and the roller 18 functions as an auxiliary guide mechanism. The rubber ring 2 pressed by the spring 19 is used to hold the cassette in the retracted state.
0 is in charge. The rubber ring 20 is driven by two provided on the plate 21, but since it has a large reduction ratio, it can perform a cassette holding function without being rotated by an external force to the roller.

(Head Pressing / Retracting Mechanism) The plate 23 is provided with a head loading mechanism. Ie plate 2
3 has slide guides 24 at both ends and slide plate 2
5 is mounted so that it can be moved up and down, and the motor 26 and the gear 2
7 is attached. The gear 27 is in mesh with a gear 27 ′ that is axially attached to the plate 23.
A link 28b having the other end connected to the slide plate 25 is connected to the. Therefore, when the motor 26 is rotated, the gear 27 rotates and the slide plate 25 moves up and down the gear 27 'and the link 28b. A thermal head 29 is attached to the slide plate 25. When printing, the slide plate 25 is lowered to press the head against the paper, and when the printing is completed, the head can be raised and retracted.

(Regulation of cassette position and retention) FIG. 4 is a diagram showing the positional relationship between the ribbon cassette 4a mounted on the printing unit and the thermal head 29 at the time of printing. The lower end of the thermal head 29 is at the center of the cassette at the time of printing. Opening 30
Then, the ink ribbon 31 is lowered together with the ink ribbon 31 to come out of the cassette to a position where the printing paper is brought into pressure contact. At this time, the position of the end 25a of the slide plate 25 to which the thermal head 29 is attached is set sufficiently close to the end 30a of the opening of the cassette so that the position of the cassette can be regulated. The end 25
A sloped portion 25b is provided in the lower part of a so that the cassette can be pushed back by the lowering of the thermal head even if the cassette position is slightly displaced.

(Cassette suction / discharge mechanism) The plate 32 shown in FIG. 2 is provided with a cassette drive unit 33 which is a ribbon cassette suction / discharge mechanism. The cassette drive unit 33 includes a plate 21, a cassette drive motor 22, a shaft 20a, two rubber wheels 20, 20, and a gear 34.
b is attached, and the rubber wheel 2 is rotated by the rotation of the motor 22.
0 and 20 are designed to rotate. Further, the cassette drive unit 33 is urged downward by the spring 19 and when the cassette comes in, the force of this spring causes the rubber ring 2 to move.
0 and 20 press the cassette to drive it.

(Identification of Ribbon Cassette and Detection of Intake Position of Cassette) The ribbon cassette 4b is pushed out from the cassette housing unit 7 (see FIG. 1) and the hollow shaft 3 of the cassette is pulled out.
When 5a35b is fitted into the shaft 17a17b of the printing unit and pushed in, and reaches the rubber rings 20, 20, the cassette is pulled in by the rotation of the rubber rings 20, 20 that have already started to rotate. The circuit board 36 is provided with four cassette identification switches 37. The circuit board 36 is arranged close to the upper part of the cassette when the cassette is inserted, and the operating lever 37a of the identification switch 37 is arranged on the upper part of the cassette. It is adapted to enter the groove 38 (see FIG. 3) provided. In this embodiment, four switches are arranged in parallel so that a 4-bit signal can be generated.

Identification chips 39 are set in the grooves 38 of the cassette in a number and arrangement corresponding to the identification numbers. The identification chips are raised so as to partially fill the grooves 38, and the cassette is pulled in to insert the chips. When the position of comes to the position of the switch lever, the switch lever with the tip is pushed up and the switch is turned on. In the embodiment, the position L of the identification chip is set so that the cassette is fully inserted, and when the identification switch 37 is turned on, the rotation of the cassette drive motor 22 is stopped.
That is, the identification switch 37 also serves to detect the position where the cassette is inserted. Although a mechanical switch is used to generate an identification signal in the embodiment, various signal generating means such as a light detecting means and a magnetic detecting means can be used. In the embodiment, the cassette identification signal also serves to detect the position of the cassette, but it may be separated.

[0016]

According to the present invention, the printing unit having the ribbon cassette exchange function, which is the most important part of the cassette exchange system, can be realized with a compact and simple structure, and also the cassette identification function can be realized. .

[Brief description of drawings]

FIG. 1 is a perspective view of a color printer equipped with a printing unit according to the present invention.

FIG. 2 is a perspective view showing an internal configuration of an embodiment of the present invention.

FIG. 3 is a perspective view of a ribbon cassette used in an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a positional relationship between an ink ribbon cassette and a print head during printing.

[Explanation of symbols]

 1 printing unit 2 carry plate 3 feed screws 4a, 3b ribbon cassette 5 paper feed roller 6 platen 7 ribbon storage unit 8 guide plate 9 frame 10 motor 11 intermediate gear 12 gear 13a, 13b shaft 14a, 14b friction mechanism 15a, 15b nailing 16 tabs 17a, 17b shafts 18 rollers 19 springs 20 rubber rings 21 plates 22 motors 23 plates 24 slide guides 25 slide plates 26 motors 27 gears 28a pins 28b links 29 thermal heads 30 openings 31 ink ribbons 32 plates 33 cassette drive units 34 gears 35a, 35b Hollow shaft 36 Circuit board 37 Identification switch 37a Actuating lever 38 Groove 39 Identification chip

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41J 35/16 B 9012-2C

Claims (5)

[Claims] 1. A thermal head, means for pressing and retracting the thermal head, means for sucking and discharging the ribbon cassette, means for guiding and holding the ribbon cassette, and means for winding the ribbon. Characteristic printing unit. 2. The printer printing unit according to claim 1, wherein a position of the ribbon cassette is regulated by a member interlocking with the thermal head when the thermal head is pressed against the thermal head. 3. The printer printing unit according to claim 1, further comprising means for detecting a suction position of the ribbon cassette. 4. A printing unit for a printer according to claim 1, further comprising a detection means of a plurality of bits for identifying each ribbon cassette. 5. The printer printing unit according to claim 1, further comprising a ribbon cassette identifying means which also serves as ribbon cassette position detecting means.