JPS58160185A - Printing apparatus - Google Patents

Abstract

PURPOSE:To obtain a printing apparatus being made capable of detecting the end of a ribbon and thereby preventing the lack of a character and the fault of erasure by a simple and inexpensive structure wherein an electroconductive member to be detected is provided in the final end part of the ribbon and the motion of a hammer is stopped by the detection of the part of this member. CONSTITUTION:An insulated member 8a for erasure and an electroconductive sensing tape 28 are bonded, by a bonding agent or the like, on the final end part of a ribbon 8 for correction rolled round a ribbon reel 27a. When electrodes 20 and 21 provided in a ribbon pressing member 19 are put in a short-circuited state by the sensing tape 28, a Schmitt trigger 29 delivers a logic output ''O'' to control a hammer unit so that it does not conduct typing through the intermediary of the ribbon 8 for correction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, and particularly to a printing device used in a typewriter or the like, which is equipped with a printing IJ, an i-”on, or a printing correction ribbon.

In recent years, printers, electronic typewriters, and other printing devices have the ability to erase and correct undesired characters once printed by printing the same type directly above them using a correction ribbon. is increasing.

The erasing member of the correction ribbon used in such a correction mechanism is a type that uses adhesive tape to remove the ink from already printed characters, or a so-called overcoat type that has a covering material of the same color as the printing paper applied to the back side. Type etc. are used. These correction ribbons are wound on reels and placed on the printing carriage in a manner that is stretched between them and the take-up reel. It is used in the form it is taken, and once used, it cannot be used again.

Therefore, when using the final part of the correction ribbon as described above, for example, if the correction ribbon has been wound up to a point where it cannot be wound any further, the user may have to make corrections. However, since the printed characters are printed through the already used portion of the correction ribbon, there is a drawback that it is not possible to completely erase undesired characters.

For this reason, several printing devices equipped with a detection device to detect the end of the correction ribbon have been proposed, but such detection devices use expensive components such as reflected light sensors and photocouplers. In order to have this mechanism, one had to be prepared for the manufacturing cost of the Katari.

Although the ribbon for printing correction has been described above, similar drawbacks occur when a printing ribbon is used.

That is, when the printing ribbon is wound up to the end, the same part of the ribbon is struck by the type C hammer), resulting in missing characters, etc. Therefore, as described above, it was necessary to detect the end of the ribbon, but this had the disadvantage of increasing manufacturing costs.

The present invention was devised in view of the above-mentioned problems, and is an electronic device having a simple structure, low cost, and equipped with a ribbon end detection mechanism that detects the end of the ribbon and automatically stops the hammer operation. The purpose of this invention is to provide a printing device suitable for use in typewriters and the like.

In order to achieve the above object, the present invention employs a configuration in which a detected member is provided at the end of the ribbon, and the hammer operation is stopped by a detection means for detecting the detected member.

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 shows the appearance of an electronic typewriter to which the printing device of the present invention is applied. Here, by pressing the character keys arranged on the keyboard 1, the type 5a provided on the type wheel 5 provided on the carriage 3 is activated.
The printer is configured so that printing is performed on the printing paper on the platen 2 by hitting the printing ribbon from the back side with the hammer 4a of the printing hammer unit 4 through the printing ribbon holder.

FIG. 2 shows an embodiment of the carriage portion of the printing device of the present invention. Here, a guide rail 10 arranged parallel to the platen 2 with three carriages passes through a guide section provided at the bottom of the lower stand 11, and is moved left and right along the guide rail 10 by a carriage drive device (not shown). It is possible.

A type wheel 5 and a print hammer unit 4 are disposed at the front of the lower base 11 of the carriage 3, in a portion facing the platen 2.
A type embossing mechanism is provided, and a printing ribbon cassette 7 containing a printing ribbon 7a is mounted behind it.

The printing ribbon 7a stored in the printing ribbon cassette 7 is pulled out from the arm portion of the cassette 7 that projects forward as shown in FIG. 3, and is stretched. This printing ribbon 7
In FIG. 2, the exposed part a is the rotating shaft 7 provided at both rear ends of the printing ribbon cassette 7 during printing operation.
A second plunger (not shown) centering on b
By rotating in the direction of the arrow in the figure, it is configured to be interposed between the type 5a of the type wheel 5 and the printing paper 6 on the platen 2.

FIG. 3 shows the lower stand 11 after the printing ribbon cassette 7 has been removed from the carriage 3.

Ribbon reels 27 &
and a take-up reel 27b are supported, and the correction ribbon 8 pulled out from both reels 27a, 27b is guided by the key-shaped shift arms 9, 9, which are supported on the left and right ends of the lower base 11. :) It is stretched between 9a and 9a. Similar to the printing ribbon 7a, the correction ribbon 8 is suspended by a plunger or the like (not shown) when erasing undesired characters. As arrow A in Figure 3
It is configured so that it can be interposed between the type 5m and the printing paper 6 by rotating in the same direction.

The rotating shaft of the winding wheel 27b passes through a hole provided in the lower stand 11, and a pulley 18 is attached to the tip thereof. 17 are hung. A drive motor 12 such as a step motor is attached to the pulley 16 via a speed reduction mechanism formed by meshing a gear 15 and a pinion gear 12a. Rotationally driven.

A shaft 23 is provided with a ribbon presser 19 on the lower stand 11 so as to bring the electrodes 20 and 21 provided thereon into contact with the unused correction ribbon 8 wound on the old ribbon reel 27a.
The bearing is mounted on the shaft. This ribbon presser 19 is constantly urged in the direction of arrow B in FIG. 3 by the urging force of a coil spring 24 attached to a shaft 234 at the bottom of the lower stand 11. The correction ribbon 8 is configured to prevent the correction ribbon 8 from winding irregularly or sagging.

At the end of the correction ribbon 8 wound around the ribbon reel 27a, as shown in FIGS. 4(5) and 4(B), an insulating erasing member 8a and a conductive sensing tape 28 are attached.
are joined with adhesive or the like.

FIG. 5(5) shows a state in which the above-mentioned ribbon presser 19 and the correction ribbon 8 wound around the ribbon reel 27a are in contact with each other.

As can be easily seen from the figure, except for the terminal end of the correction ribbon 8, as shown in FIG. 5(A), 1.5. □Eh, 9
．． - Wow, 4. 0.21? It is always in contact with the insulating erasing ribbon 8a.

A power supply voltage VCC is constantly supplied to the electrode 20 via a resistor, and the electrode 21 is grounded to the 0 potential of a metal part of the printing device or other accompanying electronic circuit. Further, an input terminal of a Schmitt trigger 29 is connected to the electrode 20 at the same time.

In the above configuration, when correcting an undesired character that has already been printed, press the key for specifying deletion provided on the keyboard 1 as an opportunity to press the correction button 1), 8 is shifted by the shift arm 9 in the direction of arrow A in FIG.

Thereafter, the hammer 4 of the printing hammer unit 4 stamps the same printed characters 5a as the undesired printed characters via the correction ribbon 8, thereby erasing the undesired characters. After this, the desired character is printed instead using the normal printing operation, and the correction is completed, but this correction ribbon 8
When the stamping is completed, the drive motor 12 is started and the pinion gear 12a is activated.

Gear 15. Pulley 16. Belt 17. The take-up reel 27b is rotated a predetermined amount of rotation via the pulley 18, and the correction ribbon 8 is wound up by a predetermined length.

Hereinafter, as long as the erasing member 8a of the correction ribbon 8 wound around the ribbon reel 2''7g continues, the above-mentioned erasing operation of undesired characters can be performed even with a narrow opening.

Here, the correction ribbon 8 wound around the ribbon reel 27a
The erasing member 8a is completely used, and the state shown in FIG. Assume that the electrodes 20 and 21 are insulated by the erasing member 8a, so that the electrodes 20 and 21 are insulated by the erasing member 8a in the state shown in FIG. 5(5). The Schmitt trigger 29 connected to outputs "1°" as a logic output, but in the state shown in Fig. 5 (b), the Schmitt trigger 29 outputs a logic output of "0" in response to the short circuit between the electrodes. Output.

The output of the above Schmitt trigger 29 is connected to another control circuit, and the output of the Schmitt trigger 29 is '1'.
→ If the printing hammer unit 4 is configured to be controlled so as to prevent printing of type 5a via the correction ribbon 8 when the temperature changes to 0°, the eraser used for erasing can be The blanking member 8a prevents incomplete erasing and engraving.

Furthermore, when the drive of the printing hammer unit 4 is stopped by the output of the above-mentioned Schmitt trigger 29, a warning lamp may be simultaneously turned on to prompt the ribbon to be replaced.

As the erasing member of the correction ribbon in the embodiments described in detail above, it is of course possible to use either the conventional erasing member of the ink stripping type or the overcoating type erasing member.

Furthermore, although the above-described embodiments have been described with respect to the print correction ribbon, the same may be applied to the print ribbon 7a. That is, the sensing tape wrapped around the end of the printing ribbon is detected by the ribbon presser 19, and based on the detection result, the printing hammer unit 4 is controlled in the same manner as described above to prevent the hammer 4a from striking. This makes it possible to remove missing characters due to the printing ribbon 7a being used twice.

By adopting the configuration of the present invention detailed above,
By providing a conductive member to be detected at the end of the ribbon and a detection mechanism for detecting this part, a simple and inexpensive structure is achieved without the use of expensive parts such as photocouplers and reflected light type optical sensors. This provides the excellent effect of being able to detect the end of the ribbon and completely preventing missing characters or erasing errors caused by the used printing ribbon or correction ribbon.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of an electronic typewriter to which the printing device of the present invention is applied, Fig. 2 is an external perspective view showing an embodiment of the carriage portion of the printing device of the present invention, and Fig. 3 is also a partially cutaway perspective view of the carriage part, FIG. 4 (
5) is a side view of the correction ribbon used in the present invention;
Figure (B) is the same top view, Figure 5 (A), CB>
FIG. 2 is an explanatory diagram illustrating the operation of the correction ribbon end detection device used in the printing device of the present invention. 4...Printing hammer yukot, 4a--hammer, 5-
... Type wheel, 5a... Type, 6... Print paper, 7... Print ribbon cassette, 7a... Print ribbon, 8... Correction ribbon, 8a... Erasing member, 9・
...Shift arm, 9a...Guide roller, 11...
・Lower stand, 12... Drive motor, 12a... Pinion gear, 15... Gear, 16, 18... Pulley, 17
...Belt, 19...Ribbon holder, 20.21.
...Electrode, 24...Coil 2 ring, 27a...
Ribbon reel, 27b... Take-up reel, 28...
・Sensing tape, 29...Schmitt trigger-0

Claims (1)

[Claims] Printing characterized in that a member to be detected is provided on a part of the ribbon surface, and means is provided for detecting the member to be detected by a detection device arranged so as to be in contact with the running surface of the ribbon and stopping the hammer operation. Device.