JPH0318589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a dot printer using magnetic ink.

Technical background of the invention and its problems Conventionally, in a dot printer that prints using a plurality of needles, a pair of ink film forming plates and their lower ends are mounted on a print head that moves along recording paper wound around a platen. A magnetic field slit is formed on the ink film forming plate, an ink film of magnetic ink is formed in this magnetic field slit, and when a needle is selectively driven, the ink is A method has been proposed in which a film of magnetic ink is deposited in the form of dots on recording paper with low noise without applying an impact force, and printing can be performed by collecting dots by repeating this process. However, with these types of printers, when the ink tank moves in conjunction with the movement of the print head, the magnetic ink inside the ink tank may move in the opposite direction to the movement direction, so the magnetic ink may spill from the ink tank. be. On the other hand, the amount of magnetic ink supplied to the magnetic field slit increases or decreases, which changes the thickness of the ink film, which increases or decreases the amount of magnetic ink deposited on the needle, causing variations in each dot. , This makes it impossible to print well. Further, in such a device, when collecting the magnetic ink from the magnetic field slit after printing is completed, the magnetic ink overflows from the passage hole of the ink tank and cannot be completely collected.

OBJECTS OF THE INVENTION The object of the present invention is to provide a dot printer in which magnetic ink does not spill from an ink tank when the ink tank is moved or when magnetic ink is collected into the ink tank.

SUMMARY OF THE INVENTION In this invention, a member that holds magnetic ink by capillary action is housed in an ink tank, so that when the ink tank is moved, the movement of the magnetic ink stored inside the ink tank is blocked, so that the magnetic ink is not removed from the ink tank. The ink does not spill, and when collecting the magnetic ink from the magnetic field slit into the ink tank, the magnetic ink is attracted by the capillary action of the member that holds the magnetic ink, so the magnetic ink does not spill from the ink tank. It is designed so that it can be collected without any waste.

Embodiment of the Invention A first embodiment of the invention will be described based on FIGS. 1 to 6. First, a platen 2 is provided horizontally in the housing 1 with its axis oriented in the left-right direction, and a carriage shaft 3 and a guide shaft 4 are provided in parallel with the platen 2. A carriage 5 is slidably attached to the carriage shaft 3 and the guide shaft 4.
The carriage 5 is connected to a known carriage moving device (not shown) comprising a pulley, a wire wound around the pulley, and a motor connected to some of the pulleys.

A print head 6 is mounted on the carriage 5. A case 7 of the print head 6 is provided with an armature guide 8 and a yoke 9. A large number of armatures 10 are housed inside the armature guide 8 in a radial manner with their movable ends directed toward the center. A large number of electromagnets 11 are arranged in a ring shape in the yoke 9, facing the armature 10. In addition, the case 7
Therein are petal-shaped leaf springs 12 that press the rear ends of the armature 10 and bias the armature 10 in a direction away from the electromagnet 11;
A stopper 13 is housed therein. The stopper 13 is in contact with the tip of the armature 10, which is biased by the leaf spring 12. and,
A PC board 14 for connecting an external circuit (not shown) and the electromagnet 11 and a guide frame 15 are attached to the front part of the case 7. A number of needles 16 corresponding to the number of armatures 10 are housed in the guide frame 15 so as to be movable toward the platen 2. these needles 1
The tips of the needles 16 are arranged in a straight line in the vertical direction, and the rear ends of the needles 16 are located inside the case 7 and arranged in a ring shape corresponding to the armature 10. Needle caps 17 are attached to the rear ends of these needles 16, and springs 18 attached to the needles 16 are engaged with these needle caps 17, thereby causing the needle caps of the needles 16 to be biased rearward. 17 is in contact with the armature 10.
Further, an ink film forming body 19 is attached to the guide frame 15. The ink film forming body 19 consists of an electromagnetic coil 20 connected to an external circuit and a pair of ink film forming plates 21 attached to both ends of the electromagnetic coil 20. A connecting plate 22 extending downward is integrally formed on the ink film forming plate 21, and the tip of each of these ink film forming plates 21 is bent so as to be parallel to the platen 2, and the respective magnetic poles 23 are connected with a gap. By facing the magnetic field slit 2
4 is formed. The tip of the needle 16 is located within this magnetic field slit 24.

A tank mounting base 25 is attached to the guide frame 15. An ink tank 26 is mounted on this tank mounting base 25. This ink tank 26 is formed into a substantially L-shape when viewed from above. In other words, this ink tank 2
The left side of the ink cassette 6 is formed so that its front-rear dimension _L1 is slightly larger than the ink cassette described later, and the front-rear dimension _L2 from the center to the right side is determined to be smaller than that of the left side. It is formed. Further, the ink tank 2
A fitting tube 27 having an oblique tip that communicates the inside of the ink tank 26 with the outside world is formed on the left side of the upper surface of the ink tank 6 . A cylindrical ink cassette 28 is removably fitted into the fitting tube 27 in a watertight manner with an open bottom end. This ink tank 2
8 stores magnetic ink 29. Next, an air hole 30 is formed on the top surface of the ink tank 26 close to the fitting tube 27, and a communication hole 31 is formed from the center of the top surface to the right side of the top surface. The connecting plates 22 are inserted into the communication holes 31, so that a passage hole 32 is formed in the communication hole 31, and a passage hole 33 communicating with the passage hole 32 is formed on the upper surface of the ink tank 26. ing.

A large number of thin fibrous wires 34 serving as members for holding the magnetic ink 29 are housed in the ink tank 26 . These thin lines 34
are stored along the left and right direction, and these thin wires 34
are housed in a stacked state with some clearance between the upper and lower surfaces of the ink tank 26, and are housed so that the left end does not reach the position directly below the fitting tube 27. Further, these thin wires 34 are selectively made of horse hair, raccoon dog hair, synthetic resin wire with a diameter of 100 μm to 50 μm, or the like.

In such a configuration, when the electromagnetic coil 20 is excited, the magnetic ink 29 in the ink tank 26
is attracted and supplied from the passage hole 32 to the magnetic field slit 24 where the tip of the needle 16 is located, and an ink film 3 having a predetermined thickness is formed in the magnetic field slit 24.
5 is formed. In this state, when the armature 10 selected based on the print signal is operated and the needle 16 is advanced toward the platen 2, the needle 16 touches the recording paper (not shown) that is wound around the platen 2 and becomes the recording section. The magnetic ink 29 that comes into contact and adheres to the tip adheres in the form of dots, and characters are formed by aggregation of dots caused by repeating this operation. At this time, the magnetic field slit 24
Since the used amount of magnetic ink 29 is rapidly supplied, the density of each dot is made uniform and good printing is performed. There are two reasons why the magnetic ink 29 is rapidly supplied to the magnetic field slit 24 at this time. The first point is that the thin wires 34 are stored in a stacked state in the ink tank 26 in the left-right direction, in other words, along the flow direction of the magnetic ink 29 in the ink tank 26. This is because the magnetic ink 29 in the ink tank 26 is reliably supplied to the passage hole 32 without excess or deficiency. The second point is that since these thin wires 34 are housed in the ink tank 26 so as not to reach the position directly below the ink cassette 28, the magnetic ink 29 stored in the ink cassette 28 quickly flows into the ink tank 26.
This is because it is supplied to

Then, during this process, when the carriage 5 moves, a force is generated that tries to move the magnetic ink 29 in the ink tank 26 in the opposite direction to the direction of movement, but the ink tank 26 stores a large number of thin wires 34. Therefore, such movement is prevented. As a result, the magnetic ink 29 flows from the air hole 30 and the passage hole 32 on the one hand, that is, from the ink tank 26.
On the other hand, a predetermined amount is supplied to the magnetic field slit 24. By supplying a predetermined amount of magnetic ink 29 to the magnetic field slit 24, a magnetic ink film 35 of a predetermined thickness is continuously formed on the magnetic field slit 24, and thereby the adhesion amount of the magnetic ink 29 on the needle 16 becomes a predetermined amount. The condition is maintained and good printing continues.

Then, when the electromagnetic coil 20 is de-energized,
The magnetic ink 29 of the magnetic field slit 24 has a thin wire 34
The ink is completely collected into the ink tank 26 without spilling from the passage hole 32 due to the suction force and gravity due to capillary action.

Next, since such an ink tank 26 is formed to be thinner from the center to the right side than the left side, the ink tank 26 is miniaturized. As a result, the tank mounting base 25 is also downsized, and the magnetic ink 29 supply mechanism is downsized. Due to the miniaturization of the ink tank 26, the surface of the magnetic ink 29 around the connecting plate 22 inside the ink tank 26 may be greatly curved due to surface tension, or air may not be able to escape due to capillary action. However, since the thin wire 34 is housed in the ink tank 26, such a phenomenon is prevented from occurring and air can be released. Therefore, since a good flow of the magnetic ink 29 is ensured, the magnetic ink 29 is well supplied to the magnetic field slit 24.

Next, a second embodiment of the present invention will be described based on FIGS. 7 to 9. Components that are the same as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted. In this embodiment, a plurality of nets 36 as members for holding the magnetic ink 29 are arranged in order in the front and back and stored in the ink tank 26.
It is rough around the edges and finer in other areas. This speeds up the supply of the magnetic ink 29 from the ink cassette 28 to the connecting plate 22, and also speeds up the supply of the magnetic ink 29 from the connecting plate 22 to the passage hole 32. Also, when the carriage 5 moves, the ink cassette 28
Since the movement of the magnetic ink 29 in the ink tank 26, which is located directly below the ink tank 26 and is most mobile, is effectively prevented by the high-density portion, the magnetic ink 29 is prevented from spilling out from the air holes 30 and the like.

In addition, as a member for holding the magnetic ink 29, there may be used a sponge (not shown), a material 37 made by collecting and hardening numerous short fibrous wires as shown in FIG. 10, and a material 37 shown in FIGS. As shown in FIG. 12, a cube 38 formed by weaving a large number of fine wires into vertical and horizontal lines may also be used.

Effects of the Invention Since the present invention is configured as described above, the magnetic ink in the ink tank is prevented from moving when the ink tank is moved, and on the other hand, it is possible to prevent the magnetic ink from spilling from the ink tank. On the other hand, it is possible to continuously supply a predetermined amount of magnetic ink to the magnetic field slit, thereby forming an ink film of a predetermined thickness and maintaining the amount of magnetic ink adhering to the needle at a predetermined amount. As a result, the density of each dot is made uniform and good printing can be performed.
When collecting the magnetic ink from the magnetic field slit into the ink tank, the magnetic ink can be collected quickly without spilling.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view showing a first embodiment of the invention, FIG. 2 is a perspective view of its print head, and FIG.
The figure is a side view with a part of the printing head cut away, Fig. 4 is a plan view of the printing head, Fig. 5 is a longitudinal sectional front view showing the main parts, and Fig. 6 is a plan view of the ink tank. , FIG. 7 is a longitudinal sectional front view showing a second embodiment of the invention, FIG. 8 is a longitudinal sectional side view of a part thereof, and FIG. 9 is a perspective view showing an enlarged main part thereof.
FIG. 10 is a perspective view showing a modification of the present invention;
FIG. 1 is a longitudinal side view showing another modification of the invention;
FIG. 12 is an enlarged perspective view of the main part. 6...Print head, 16...Needle, 21...
... Ink film forming plate, 24 ... Magnetic field slit, 26
...Ink tank, 28 ...Ink cassette, 2
9...magnetic ink, 34...fine wire (member that holds magnetic ink), 36...net (member that holds magnetic ink), 37...numerous short fibrous thin wires collected and solidified. (member that holds magnetic ink), 38... A cube-shaped object made by knitting a large number of thin wires into vertical and horizontal lines (member that holds magnetic ink).

Claims (1)

[Scope of Claims] 1. A pair of ink film forming plates are attached to a print head that moves along a recording section, and magnetic field slits are formed in these ink film forming plates to cause magnetic ink to adhere to the needle, An ink tank communicating with the lower part of the ink film forming plate is provided, an ink cassette storing the magnetic ink is detachably attached to the ink tank, and a member for holding the magnetic ink by capillary phenomenon is housed in the ink tank. A dot printer that is characterized by 2. Claim 1, characterized in that the member that holds the magnetic ink by capillary action is formed with a large number of thin fibrous wires, and these thin wires are housed along the lower part of the ink film forming plate. Dot printer mentioned in section. 3. The dot printer according to claim 1, wherein a member for holding magnetic ink by capillary action is housed in the ink tank so as not to be located directly below the ink cassette. 4. The dot printer according to claim 1, wherein the density of the member that holds the magnetic ink by capillary action is rough around the lower part of the ink film forming plate and fine elsewhere.