JPH0530925Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an identification mark reading mechanism for an impact printer that prints dots by pressing an ink ribbon against a recording medium using a print head wire. This is designed to prevent the mounting position of the sensor from being misaligned due to non-standard thick paper, unexpected contact during maintenance, etc.

[Conventional technology]

Conventionally, in this type of impact printer, in order to strengthen the office computer, it is known that an identification mark displayed on a recording medium is read by a sensor, and ledger processing is performed based on the signal.
The sensor consists of a light-emitting element and a light-receiving element, and is arranged opposite to the recording medium with a small distance (approximately 0.3 to 0.4 mm) in order to improve the accuracy of reading the identification mark.

[Problem that the invention attempts to solve]

However, in such conventional identification mark reading mechanisms, the sensor is fixedly arranged via a bracket to the carriage in which the print head is mounted, so there is a possibility that non-standard thick paper or foreign matter may be accidentally fed in, or that it may be damaged during maintenance. Accidental contact may damage the sensor.
Furthermore, even if the bracket is not damaged, if the bracket is bent, the distance between the sensor and the recording medium increases, making it difficult to read the identification mark.

[Means for solving problems]

The identification mark reading mechanism for an impact printer according to the present invention was developed to solve the above-mentioned problems. The sensor case includes a sensor case that holds a sensor for reading the identification mark of the recording medium, and a bracket disposed in the printing mechanism and in which a guide member is embedded, and the sensor case is slidable up and down on the guide member of the bracket. The sensor is supported and disposed so as to be close to and opposite to the recording medium, and a biasing means is provided for biasing the sensor case downward along a guide member.

[Effect]

In this invention, the sensor is arranged so that it can move up and down, so that if non-standard thick paper or foreign objects are accidentally fed in or touched during maintenance, the sensor case that holds the sensor will move along the guide member of the bracket. It escapes upward while maintaining its horizontal position, and then returns to its original position by the force of the biasing means, so the sensor is not damaged or misaligned, and identification marks can be reliably read. .

〔Example〕

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

FIG. 1 is a side sectional view showing an embodiment of the identification mark reading mechanism according to the present invention, FIG. 2 is a perspective view of a printing mechanism section equipped with the same mechanism, and FIG. 3 is a sectional view of a printing head. In these figures, 1 indicates a pair of guide shafts 2 and 3 arranged in parallel in the vertical direction.
A carriage that is moved back and forth in a direction (direction of arrow B) perpendicular to the feeding direction (direction of arrow A) of recording medium (short length of printing paper, continuous paper, etc.) 4 along the head 5,
A card holder 6, a timing belt 7, a guide film 8, etc. are disposed, and an ink ribbon 9, which is fed in the direction of movement of the carriage 1, is disposed corresponding to the print head 5, and these constitute a printing mechanism. are doing.

The printing heads 5 are conventionally known, and as shown in FIG.
For example, 24 elongated printed wires 11 and a plurality of leaf springs 13 each elastically supporting the upper end of each printed wire via an armature 12.
It is generally composed of a guide plate 14 and a tip guide 15 that guide each print wire 11, and a plurality of coils 16 and magnets 17 that individually drive each print wire 11. The print wires 11 are arranged in two rows of 12 wires at a predetermined interval in the direction of movement of the carriage 1, and the wires in each row are arranged in a line in the direction in which the recording medium 4 is fed.

The card holder 6 is formed of transparent plastic into a substantially L-shape, and its vertical part 6A is fixed to the lower part of the carriage 1, its horizontal part 6B is located below the print head 5, and the ink ribbon 9 is connected to the card holder 6. This horizontal portion 6 is interposed between the platen 18 and the horizontal portion 6.
The recording medium 4 is fed between B and the platen 18. An opening 19 is provided in the center of the horizontal portion 6B, and a mask 20 is attached to cover the opening 19. The mask 20 is formed of stainless steel or the like into a thin plate shape (about 0.1 mm thick), and a ribbon hole 21 is formed in the center thereof corresponding to the print wire 11.

Therefore, while the carriage 1 is reciprocated along the guide shafts 2 and 3, the coil 16 is energized to selectively move the armature 12, displacing the print wire 11 downward and projecting it below the case 10. Then, this wire 11 presses the portion of the ink ribbon 9 corresponding to the ribbon hole 21 against the recording medium 4, whereby desired characters, symbols, etc. are printed in dots with each reciprocating movement.

The guide film 8 is used to prevent the printed line portion of the recording medium 4 from lifting up along with the card holder 6, and is made of a transparent and flexible band-shaped body, and both ends 8a and 8b of the guide film 8 are attached to the carriage 1. It is fixed to a substantially L-shaped bracket 25 attached to the lower front surface, and surrounds the front and back surfaces of the recording medium 4.

Now, the identification mark reading mechanism 30, which constitutes the gist of the present invention, is arranged so that it can escape upwardly with respect to the recording medium 4, and is installed on the bracket 25 as shown in FIG. A sensor case 33 is placed on the bracket 25 and has a pair of left and right guide pins 31 and a pair of left and right insertion holes 32 through which each guide pin 31 passes, and a sensor case 33 is stored in a sensor storage recess 33a of this sensor case 33. A pair of compression coil springs 36 are fitted around the outer periphery of each guide pin 31 to press the sensor case 33 against the bracket 25, and are fixed to the upper end surface of each guide pin 31 by a set screw 37. Washer 38 that prevents compression coil spring 36 from coming off
It is composed of etc. The gap G between the lower surface of the sensor case 33 and the platen 18 is set to be approximately equal to the distance between the lower surface of the print head 5 and the platen 18. Further, the lower front surface of the sensor case 33 is cut off diagonally to form a guide surface 39 so that the recording medium 4 can be fed smoothly and reliably. Note that the lower surface of the sensor case 33 is normally located below the lower surface of the bracket 25.

In the identification mark reading mechanism 30 having such a configuration, when a non-standard recording medium or a foreign object that is thicker than the gap G is fed into the sensor case 33, or when a hand or a tool hits the sensor case 33 from below during maintenance, etc. Since the sensor case 33 is pushed upward along the pair of guide pins 31 against the compression coil spring 36, the sensor case 33 is not damaged and the bracket 25 is not deformed, and the recording medium and foreign objects are not damaged. After it is removed, the sensor 34 is lowered and returned to its original position by the force of the spring 36, so the mounting height of the sensor 34 will not be disturbed and the gap G with the platen 18 can be maintained constant. Therefore, the identification mark displayed on the recording medium 4 can be reliably read.

In addition, although the compression coil spring 36 was used as the elastic member for urging the sensor case 33 downward in the above embodiment, the present invention is not limited to this, and it is also possible to use a plate spring, elastic rubber, or the like.

[Effect of idea]

As explained above, the identification mark reading mechanism of the impact printer according to the present invention includes a sensor case that holds a sensor for reading an identification mark on a recording medium, and a bracket that is disposed on the printing mechanism and has a guide member implanted therein. The sensor case is supported vertically and slidably on the guide member of the bracket, and the sensor is disposed so as to closely face above the recording medium, and the sensor case is pushed downward along the guide member by a biasing means. Since the sliding amount of the sensor case with respect to the guide member of the bracket can be freely set, the adjustable range of the recording medium thickness is expanded, and it also prevents foreign objects or non-standard thick recording media from being fed in. When an external force is applied from below during maintenance, etc., the sensor is pushed up against the biasing member and escapes upward, so the sensor is not damaged or the bracket to which the sensor is attached is not deformed.
In addition, when the sensor is pushed upward, the sensor case slides along the guide member of the bracket, so the sensor case moves upward while maintaining its horizontal position. In other words, the sensor case and the recording medium Parallelism is maintained, and therefore, the identification mark can be reliably read by the sensor with high accuracy.

In addition, the structure is simple and existing products can be easily improved, and its practical effects are extremely large.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the identification mark reading mechanism according to the present invention, FIG. 2 is a perspective view of a printing mechanism section equipped with the same mechanism, and FIG. 3 is a sectional view of a printing head. 1... Carriage, 2, 3... Guide shaft, 4... Recording medium, 5... Print head, 9...
Ink ribbon, 11...Print wire, 18...
... platen, 25 ... bracket, 31 ... guide pin, 33 ... sensor case, 34 ... sensor, 36 ... compression coil spring.

Claims (1)

[Scope of utility model registration request] In an impact printer that performs dot printing by pressing an ink ribbon onto a recording medium using a print wire of a printing mechanism, a sensor case that holds a sensor that reads an identification mark on the recording medium;
a bracket disposed on the printing mechanism and having a guide member implanted therein; the sensor case is vertically slidably supported on the guide member of the bracket so that the sensor is positioned above the recording medium in close proximity to and opposite to the recording medium; An identification mark reading mechanism for an impact type printer, characterized in that the identification mark reading mechanism for an impact printer is provided with a biasing means for biasing the sensor case downward along a guide member.