JPS602378A - Dot printer - Google Patents

Abstract

PURPOSE:To reduce printing noise and enable to prevent a magnetic ink from being splashed onto a recording paper, by a method wherein a magnetic ink layer is provided between magnetic poles opposed to each other, and a tip face of a needle is located in proximity to an outer layer surface on the recording paper side of the ink layer. CONSTITUTION:When an electric current is passed to a magnetic ink attracting coil, a magnetic ink 24 contained in an ink tank 20 is attracted by a magnetic flux generated between the magnetic poles 19, thereby forming a magnetic ink layer 36 along a slit 18, so that a tip part of the needle 9 is wetted with the magnetic ink 24. The tip face of the needle 9 is located in proximity to the outer layer surface 37 of the ink layer 36. When the needle 9 is protruded toward the recording paper 34 so as to lightly touch the latter in accordance with a printing signal, the ink 24 adhered to the tip of the needle 9 is transferred onto the paper 34 without generating any collision sound. In addition, since the needle 9 is protruded from the state of being proximate to the outer layer surface 37 of the ink layer 36, clear printing can be performed with an appropriate transfer quantity, and the ink is prevented from being splashed onto the paper 34.

Description

[Detailed description of the invention] Technical field of invention This invention relates to a dot printer.

Technical background of the invention and its problems Conventional dot printers impact pressure-sensitive paper along a platen with a needle, or impact plain paper with an ink ribbon. In any case, the collision between the needle and the platen causes a lot of printing noise.

For this reason, a printing method has been considered in which magnetic ink in an ink tank is attracted by magnetic force between opposing magnetic poles, and a needle wetted with the magnetic ink is slid toward the recording paper. However, the amount of magnetic ink transferred from the needle tip to the recording paper varies,
There is a problem that the print density is not constant.

OBJECT OF THE INVENTION The present invention was made in view of the above-mentioned points, and it is an object of the present invention to provide a dot printer that can reduce printing noise and maintain a constant printing density.

Summary of the Invention The invention involves sucking magnetic ink from an ink tank between opposing magnetic poles to form a magnetic ink layer, and then sliding a needle to transfer the magnetic ink attached to the tip of the needle onto recording paper. By forming dots, the printing pressure can be significantly lowered, making printing noise extremely small.Furthermore, by bringing the tip of the needle close to the surface of the magnetic ink layer on the recording paper side, In addition, it controls the amount of magnetic ink scattered by penetrating the magnetic ink layer when the needle is operated, and maintains the needle tip surface wet with magnetic ink, thus ensuring clear printing with optimal density. It is composed of

Examples of the invention An embodiment of this invention will be described based on the drawings.

(1) is a housing, and this housing (1) has a print head (2).
A fully loaded carrier (3) is held by a carrier shaft (4) and a guide shaft (5) and is slidably provided. A cover (6) is provided on the top surface of the housing (1), although only a portion thereof is shown. Print head (2)
is similar to a guide frame αQ holding a plurality of electromagnets (7) 'em arranged in an m-shaped magnet case (8) and a plurality of needles (9). The armature α blade of each electromagnet (7) comes into contact with the needle (9) and is urged in the return direction by the needle spring (2), causing the stopper α9
is pressed against. The guide frame αQ has a needle (
9) is fixed to the needle guide α4 (to) that aligns the needle guides α4, and magnetic plate α forces coupled to both poles of the magnetic ink suction coil αG are fixed to both sides of this guide frame αQ, and the tips of these magnetic plates αη are fixed. , magnetic poles 0I facing each other with slit 0→ in between are formed continuously, and the tip of the needle (9) protrudes from the slit ◇.

Further, a flat ink tank holder and a cartridge H are detachably attached to the print head (2). A small slit hole (c) into which the lower end of the magnetic pole α is inserted and a through hole (c) located in the center are continuously formed on the top surface of the ink tank holder, and a through hole (c) located in the center is formed in succession. An opening (c) is formed. A permanent magnet (C) is fixed to the bottom surface of the ink tank (A), with the lower end of the magnetic poles α facing each other. A cylinder (c) is formed on the lower surface of the cartridge Q■ to be fitted into the opening (c), and an opening (c) is formed at the lower end of this cylinder (a) to discharge the magnetic ink He inside. A plug (C) that closes the opening (C) when the tube is in close contact with the cylinder (B) is fitted into the tube (B) so as to be able to move up and down while being biased downward by a spring (G). In addition, a rod 0 is formed protruding from the bottom surface of the plug (c), and a plurality of notches 0 are formed on the outer periphery.
■ is formed. The radius of the circle connecting the bottoms of these notches is also thicker than the radius of the vaginal opening (c).

Furthermore, a paper feed roller 01 is provided in front of the print head (2).
A recording paper (341) is supported by a permanent magnet.

In such a configuration, when the magnetic ink attraction coil αG is energized, the magnetic flux generated between the magnetic poles α attracts the magnetic ink in the ink tank □□□, forming a magnetic ink layer 0→ along the sulin)H. The tip of the needle (9) is coated with magnetic ink (c). Therefore, when the specified electromagnet (7) is excited and the needle (9) is sent toward the recording paper (b), the magnetic ink (c) at the tip of the needle (9) comes into contact with the recording paper (b). Form a dot. In this case, if the tip of the needle (9) lightly touches the recording paper 0Φ, a dot is formed, so there is no collision sound as in the conventional case, and the noise is extremely low. According to this embodiment, when the tip of the needle (9) approaches the recording paper (b), the permanent magnet Ov attracts the magnetic ink (c) at the tip of the needle (9), so that the stroke of the needle (9) is It is also possible to further reduce printing noise by setting a small stroke that does not contact ←◇.

Also, the magnetic force of the magnetic ink attraction coil αG is constant;
The magnetic ink (c) in the ink tank is replenished from the cartridge Qυ according to the amount consumed, so it is maintained at a constant level. Therefore, the level of the magnetic ink layer at the slit α is also constant and is transferred to the upper needle (9). Magnetic ink (
There is no situation in which (c) is not reached.

As shown in FIG. 6, the needle (9
) If the return position is +α when the leading edge is located on the recording paper (B) side and the return position is −4 when it is located on the opposite side, then if the needle (9) is roughly flown from each position and printed, As shown in FIG. 7, the amount of magnetic ink (c) transferred to the recording paper (b) is so small that the tip surface of the needle (9) is closer to the recording paper 0→ side, so that printing is performed. The amount of magnetic ink (c) scattered onto the recording paper (b) increases as printing is performed from a position where the leading edge of the magnetic ink layer 0→ is drawn into the magnetic ink layer 0→. By determining the thickness of the armature αη, the return position of the armature α℃ by the stopper α9, the total length of the needle (9), the position of the magnetic pole α, the magnetic force of the magnetic ink suction coil αQ, etc.
) The tip surface is brought close to the surface layer surface 0'I) of the magnetic ink layer OQ. Therefore, magnetic ink (
The amount of transfer (c) is appropriate, and it is possible to print clearly.

In addition, even if the tip surface of the needle (9) is +a with respect to 0, the variation in a is suppressed to a very small level, so the tip surface of the needle (9) will not be affected by the magnetic ink ( c) get wet. On the other hand, even if it is 2α, the variation in α is kept to a minimum, so the amount of magnetic ink (c) scattered onto the recording paper (b) is also small.

Effects of the Invention Since the present invention is constructed as described above, the printing pressure of the needle against the recording paper can be significantly reduced, thereby making it possible to significantly reduce printing noise.Furthermore, the magnetic ink layer between the magnetic poles can be Since the needle tip is placed close to the surface layer, it is possible to wet the needle tip with magnetic ink and suppress the scattering of the magnetic ink onto the recording paper, making it possible to print clearly with appropriate density. It has the following effects.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view showing the overall configuration with a reduced size and a part cut away, FIG. 2 is a plan view, FIG. 3 is a vertical side view, and FIG. 4 5 is an exploded perspective view, FIG. 5 is an enlarged front view with a portion cut away, FIG. 6 is an enlarged plan view showing the positional relationship between the needle tip and the magnetic ink layer, and FIG. 7 is the position and position of the needle tip surface. 7 is a graph showing the relationship between the amount of magnetic ink transferred to recording paper; 9... Needle, 16... Magnetic ink suction coil,
18... Slit, 19... Magnetic pole, 20... Ink tank, 24... Magnetic ink, 34... Recording paper,
36...Magnetic ink layer, 37...Surface surface 3/resistance] Chopper 5 Figure] 6 History factor 1α

Claims (1)

[Claims] Magnetic poles that are magnetically coupled to a magnetic ink suction coil and face each other with a gap If are provided, and the lower ends of these magnetic poles are inserted into an ink tank containing magnetic ink and immersed in the magnetic ink, so that the magnetic ink is absorbed by the magnetic force. A plurality of needles that capture the magnetic ink attracted between the magnetic poles and transfer it to recording paper are slidably provided between the magnetic poles, and a surface layer of the magnetic ink layer formed between the magnetic poles on the recording paper side. A dot printer characterized in that the tip end surface of the needle is located at a position close to.