JPH0767842B2 - Thermal printing equipment - Google Patents

Description

The present invention relates to a paper (recording sheet) arranged on a platen by utilizing heat generated by a thermal head that moves an ink ribbon cassette on a carriage (carriage). The present invention relates to the structure of a thermal printing device capable of transferring ink to the ink.

[Prior Art] In printers such as thermal printers that print by sliding the print head while pressing the ink ribbon or thermal ribbon against the paper, the ribbon feeding operation and the print head up / down (separation and press contact with the paper). ) It is necessary to precisely control the operation in a timely manner.

However, in the conventional thermal printer (thermal printing apparatus), the ribbon feeding and the press contact of the print head are performed by separate driving systems, so that the control is difficult and a complicated control unit is required. there were.

Further, since accurate control cannot be performed, there is a drawback that ribbon loosening or biting occurs due to carriage movement or ribbon feeding error.

〔Purpose〕

The object of the present invention is to solve the above-mentioned problems of the prior art.
Up and down of the thermal head and on / off control of the ink ribbon take-up drive force transmission can be performed easily, accurately, with a low impact and quickly, and the loosening of the ink ribbon and the occurrence of winding of the ink ribbon in the thermal head are prevented. It is to provide a thermal printing device that can do so.

[Summary] According to the present invention, in order to achieve the above object, an ink ribbon cassette is arranged on a carriage and ink generated on a recording sheet arranged on a platen is utilized by utilizing heat generated by a thermal head moving together with the carriage. In a thermal printing apparatus capable of transferring a sheet, a head displacing unit that is provided on the carriage and that displaces the thermal head between a recording position and a retracted position that retracts from the recording position; and the thermal head and the head displacing unit. Elastic means disposed between the first rotating member and the first rotating member provided on the carriage, the first rotating member facing the platen over the movable range of the carriage, and engaging with the first rotating member. A rotation imparting means for rotating the first rotating member by a moving force of the carriage; And an ink ribbon winding drive for winding the ink ribbon stored in the ink ribbon cassette by engaging with the first rotating member and rotating about the rotation axis of the first rotating member. And a second rotating member capable of being displaced between a position capable of transmitting a force to the ink ribbon cassette and a position not capable of transmitting the force to the ink ribbon cassette.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 to 4, a sleeve 3, a first gear 4, and a ratchet 5 are provided on a vertical shaft 2 which is planted on a carriage 1 driven along a sheet by a pulse motor (not shown). And the second gear 6 is rotatably supported in a coaxial relationship. In the illustrated example, the first gear 4 and the ratchet wheel 5 are supported on the outer circumference of the sleeve 3. The arrow PT in FIG. 1 indicates the printing direction, and the opposite direction is the carriage return direction.

The sleeve 3 is regulated by a spring clutch 8 whose one end is locked to the fixed portion 7 of the carriage so as to rotate in the direction (right direction) indicated by an arrow A in FIG. 1 but not in the opposite direction.

The first gear 4 meshes with a rack installed in the printer body over the carriage movement range, and is rotationally driven in conjunction with the movement of the carriage 1. That is, when it moves in the printing direction PT, it is driven so as to rotate rightward in the direction of arrow A in FIG. Also, the first gear 4 and the sleeve 3 are
It is connected by a spring clutch 10 that transmits right rotation (direction of arrow A in FIG. 1) but does not transmit left rotation.

The sleeve 3 and the second gear 6 are connected by a spring clutch 11 that transmits right rotation but not left rotation. By the way, both ends of the spring clutch 11 are engaged with the ratchet wheel 5 and the second gear 6. Therefore, when the ratchet wheel 5 is in a free state, the clockwise rotation of the sleeve 3 causes the ratchet wheel 5 and the second gear 6 to rotate. Although transmitted to both gears 2 of the second gear, when the rotation of the ratchet wheel 5 is stopped by some means, the spring clutch 11 loosens and the rotation of the sleeve 3 is applied to both the ratchet wheel 5 and the second gear 6. It is not transmitted.

A cam wheel 12 is supported on the carriage 1, and a concentric cam gear 13 is integrally provided on the cam wheel 12. Then, the second gear 6 meshes with the cam gear 13. In the illustrated example, the gear ratio is set to 2: 1, and when the second gear 6 rotates by a certain angle, the cam wheel 12 rotates twice in the direction of arrow B.

This cam wheel 12 has two ridges 1 on the circumference of the end face (upper face).
There are provided end face cams having 4,14 and peripheral face cams 15,15 having horizontally extending portions 15,15 formed at two locations on the outer periphery. The end face cams 14, 14 are for controlling the up / down operation of the thermal head (print head),
The peripheral cams 15 and 15 are for controlling ON / OFF of driving of the ribbon cassette (unwinding of the ribbon).

A solenoid 16 is mounted on the carriage 1. The movable portion 17 of the solenoid is an operating member that swings around a support shaft 18.
Combined with 19.

One end of the operating member 19 is connected via a pin 20 to a claw member 22 which is swingably supported by a support shaft 21. The claw member is in the position shown in FIG. 1 when the solenoid is OFF, and in the position shown in FIG. 3 when the solenoid is ON.

That is, the pawl member 22 has two presser pawls 2 at predetermined intervals.
3, 24 are formed. When the solenoid is ON, the presser pawl 23 engages with the ratchet wheel 5 (Fig. 3), and when the solenoid is OFF, the presser pawl 2
4 is arranged to engage with the ratchet wheel 5 (FIG. 1).

Further, the operating member 19 engages with a stopper member 25 swingably supported by the support shaft 18 to turn off the solenoid (first
When the solenoid is ON (FIG. 3), the stopper member is biased to the disengaged position in the clockwise direction in the case of FIG.

An up / down motion transmission member 26 for moving the print head up and down is supported on the carriage 1 so as to be swingable on a shaft 27. The up / down motion transmission member 26 is provided with end cams 14, 14 of the cam wheel 12 via a cam follower 28.
Driven by. Thus, the solenoid 16 is ON and the up-down motion transmission member 26 is formed at the ridges of the end cams 14, 14.
If the solenoid is in the ON state even after the stopper member 25 has entered the lower side of the up / down motion transmitting member and the ridge has passed when the head is lifted (head-down motion), it is shown in FIG. The print head can be held in the down position, that is, the pressure contact position.

In the illustrated example, the up / down motion transmitting member 26 is connected to the print head operating unit 30 via a torsion spring 29, and has a structure capable of absorbing a shock during the up / down motion.

As shown in FIG. 4, the first gear 4 is always in mesh with the ribbon cassette driving gear 32 via an idle gear 31. The idle gear 31 is rotatably supported on a vertical shaft 33 provided on the carriage 1. The ribbon cassette drive gear 32 is rotatably supported on a vertical shaft 35 provided on an oscillating member 34 that can oscillate about the vertical shaft 33. The vertical shaft 35 is provided with a cam follower 36 that comes into contact with the peripheral cams 15, 15 of the cam wheel 12. Reference numeral 37 indicates a spring for pressing the cam follower 36 against the circumferential cam.

Therefore, depending on the rotational position of the cam wheel 12, the ribbon cassette drive gear 32 is in the OFF position shown in FIG.
It is driven to the ON position shown in the figure, and this controls the ribbon feed OFF / ON.

The operation is as follows.

In Fig. 1, the solenoid 16 is turned off to raise the print head (separate), and the carriage 1 is moved slightly to move the cam wheel.
12 shows the state that the ribbon feed is turned off.

When printing, the solenoid is turned on and the claw member 22 is brought into the state shown in FIG. While the carriage 1 slightly moves and the ratchet wheel 5 rotates between the two presser pawls 23 and 24 of the pawl member 22, the cam wheel 1
The print head is pressed into contact with the second end cam 14 and the stopper member 25 in cooperation with each other, and at the same time, the ribbon feed is also turned on.
It becomes the state of the figure. Printing is thus performed.

When the solenoid 16 is turned off to move the print head up (separate), the stopper member 25 separates and the print head is immediately moved up. If the carriage 1 is moved slightly (until the next pawl engages the presser pawl 24), the cam wheel 12 rotates in the direction of the arrow B at a predetermined angle, and the peripheral cam 15 swings via the cam follower 36. The member 34 is swung, the ribbon cassette drive gear 32 is turned off, and the ribbon feed is turned off.
Set to FF. This state is the state shown in FIG.

According to the embodiment described above, the end face cams 14 and 14 for press-contacting the print head and the peripheral face cams 15 and 1 for turning the ribbon feed OFF are attached to the cam wheel 12.
Since 5 and 5 are integrally provided, ON / OFF control of ribbon feeding can be easily and easily controlled in time with the up / down movement of the print head.

In this way, the possibility of ribbon slack or entanglement can be almost eliminated.

Further, the solenoid 16 only drives the stopper member 25 (a kind of trigger), and the up and down movement of the print head is performed by moving the carriage 1, that is, by using a pulse motor which is originally large as a drive source, so that the solenoid can be reduced in size and weight. Can be planned.

In this way, a thermal printing apparatus can be obtained which can control the ribbon feeding as well as the up and down movement of the print head with only a small solenoid having one pulse motor.

Further, since these controls can be executed at a proper timing only by turning on / off the solenoid, the control circuit can be simplified.

In particular, since the print head immediately rises when the power is turned off, it is possible to eliminate the risk of damaging the paper when the paper is taken in and out.

Further, since the up / down operation of the print head is performed via the cam wheel, it is possible to eliminate the impact at the time of head pressure contact, thereby preventing the paper from being soiled.

〔effect〕

As is clear from the above description, according to the present invention, the elastic means is arranged between the thermal head and the head displacement means,
A first rotating member, a rotation applying unit that rotates the first rotating member, and an ink ribbon take-up driving force to the ink ribbon cassette by rotating about a rotation axis of the first rotating member. By providing a second rotating member that can be displaced between a position that can be transmitted and a position that cannot be transmitted, the thermal head up / down and on / off control of the ink ribbon winding drive force transmission can be performed easily, accurately, and with low impact. It is possible to obtain a thermal printing apparatus that can be rapidly and quickly prevented from loosening the ink ribbon and preventing the ink ribbon from being caught in the thermal head.

[Brief description of drawings]

FIG. 1 is a partially-deleted plan view showing an embodiment of a thermal printing apparatus according to the present invention in a state where the ribbon feeding is OFF, FIG. 2 is a vertical sectional view taken along line II-II in FIG. The figure is first
FIG. 4 is a plan view showing the apparatus shown in the drawing with the ribbon feeding turned ON.
The drawing is a vertical sectional view taken along the line IV-IV in FIG. 1 ... Carriage, 3 ... Sleeve, 4 ... First gear,
5 ... Claw wheel, 6 ... Second gear, 8,10,11 ... Spring clutch (one-way clutch), 9 ... Rack, 12 ... Cam wheel, 14 ... End cam, 15 ... Circumference Surface cam, 16 ... Solenoid, 17 ... Movable part, 22 ... Claw member, 25 ... Stopper member, 26 ... Up / down motion transmission member, 31 ... Idle gear, 32 ... Ribbon cassette drive gear, 34 …… Rotating member, 36 …… Cam follower.

Claims (1)

[Claims] 1. A thermal printing apparatus, wherein an ink ribbon cassette is arranged on a carriage, and the heat generated by a thermal head moving together with the carriage is used to transfer ink to a recording sheet arranged on a platen, the thermal printing apparatus being provided in the carriage. A head displacing means for displacing the thermal head between a recording position and a retreat position for retracting from the recording position; an elastic means arranged between the thermal head and the head displacing means; And a first rotating member that is provided across the movable range of the carriage so as to face the platen, engages with the first rotating member, and rotates the first rotating member by the moving force of the carriage. Rotation imparting means, and the first rotation part provided on the carriage and engaged with the first rotation member. By rotating around the rotation axis of the ink ribbon, the ink ribbon winding drive force for winding the ink ribbon stored in the ink ribbon cassette is displaced to a position where it can be transmitted to the ink ribbon cassette and a position where it cannot be transmitted. And a possible second rotating member.