EP0015784B1

EP0015784B1 - Fountain pen

Info

Publication number: EP0015784B1
Application number: EP80300784A
Authority: EP
Inventors: Koichi Murahara; Teibun Yasunaga
Original assignee: Pilot Man Nen Hitsu KK
Current assignee: Pilot Corp
Priority date: 1979-03-13
Filing date: 1980-03-13
Publication date: 1984-01-18
Also published as: DE3066123D1; EP0015784A1

Description

This invention relates to a fountain pen provided with means for automatically supplying ink to its nib in a controlled manner.
A conventional fountain pen has a feed for feeding ink from an ink reservoir to the nib. The feed has an ink groove along which the ink runs, and an air groove for introducing air. Unfortunately, if an ink reservoir having a large capacity is provided in the pen holder, ink may flow over the nib, resulting in ink dripping. This occurs because the ink may be supplied to the nib at an excessively high rate due to a pressure or temperature change.
As the ink is used, the internal pressure in the ink reservoir decreases until air is drawn into the ink reservoir, at which time the internal pressure increases. Thus, when writing with the pen, the internal pressure in the ink reservoir alternately decreases and increases, resulting in a pulsating flow of ink.
As a result, the user's handwriting is likely to be irregular in density.
In order to give accent to handwriting, it is necessary to increase the writing pressure. Upon increasing the writing pressure in a conventional fountain pen, the slit in its nib tends to open thereby stopping the flow of ink onto the paper. Moreover, if a conventional fountain pen is not used for a relatively long time, the ink tends to dry making it difficult to commence writing satisfactorily.
The aim of the invention is to provide a fountain pen which does not suffer from the above-described difficulties.
The present invention provides a fountain pen comprising a nib, an ink reservoir, means for transferring ink from the ink reservoir to the nib, an electric power source for powering the transfer means, and a detector for detecting the quantity of ink in an ink pool adjacent to the nib, the detector controlling the supply of power to the transfer means, wherein the ink pool is formed between the nib and an ink holder.
The provision of the detector overcomes the above-described difficulty that air flows into the ink reservoir, thus causing the ink to drip and produce a pulsating flow of ink.
Advantageously, the nib has a slit region. The ink pool allows the ink to be transferred continuously onto a sheet even if the slit in the nib is opened, and to commence writing satisfactorily even if the nib was initially dry. Moreover, even if the ink has dried in the slit, application of writing pressure will open the slit to break the dried ink so that ink can again pass through the slit to the point of the nib. In this connection, as the ink pool is adjacent to the nib, the ink can be more quickly supplied than if the ink pool were to be provided at other positions.
The ink holder may be in the form of a flat plate or a plate member which is curved, in cross-section, towards the nib. Alternatively, the ink holder may be in the form of a flexible cylinder having a hole which communicates with the slit region of the nib. Again, the pen may further comprise a feed, and the ink holder may be formed as a recess in a surface of the feed which confronts the slit region of the nib. Only an ink introducing path which joins the ink reservoir to the ink pool need be provided in the feed.
The ink pool formed between the ink holder and the nib may be provided on the upper surface of the slit region of the nib, on the lower surface of the slit region of the nib, or on both the upper and lower surfaces of the slit region of the nib.
It is desirable that the ink pool be merely a gap or clearance between the nib and the ink holder. In this case, it is preferable that the gap be so designed that capillary action occurs in the gap. With this construction, no ink leakage is possible and ink can be positively delivered to the end of the slit region of the nib independent of the angle at which the fountain pen is held. It is not always necessary that the capillary gap be provided over the entire length of the ink pool.
Advantageously, the nib is supported by a pen holder, and the pen holder houses the ink reservoir. Preferably, the transfer means comprises an ink delivery device associated with the ink reservoir, a power delivery circuit connecting the electric power source to the ink delivery device, and a switch circuit connecting the detector to the delivery circuit. The transfer means may be housed within the pen holder.
The detector may be a single electrode, or a pair of electrodes provided in the ink pool. The detector may also be formed by one electrode and the nib or the ink holder. Alternatively, the detector may comprise photoelectric elements provided at predetermined positions outside the ink pool. More specifically, such a detector may be formed by a light-receiving element only, a combination of a light-receiving element and a light-emitting element, or a combination of such light-receiving and emitting elements and glass fibres confronting these elements in the ink pool. An electrostatic capacity detector may also be employed, in which case the entire ink holder, which is electrically insulated, is one of the electrodes.
The ink reservoir may be a bellows-shaped member, a cartridge, or the combination of a piston and a cylinder. In any case, it is essential that the ink reservoir is open to the ink pool. For improving the ink supplying conditions, at least the inside surface of the mouth of the ink reservoir, which is in the ink pool, should be made of a water-repellent material such as Teflon (Registered Trade Mark) or polyethylene.
The ink delivery device may comprise an electric motor and a piston coupled to the output shaft of the motor for depressing the ink reservoir. In this case, a bellows-shaped member reservoir or an ink reservoir constituted by a piston and cylinder is most suitable.
Alternatively, the ink delivery device may comprise an electromagnetic valve provided between the ink pool and the ink reservoir, and a pressurising member provided at the side of the ink reservoir remote from the ink pool. In this case, the pressurising member may be a stretchable or expandable member, in which compressed gas or pressurised liquid is stored for pushing out the ink, and the means together with ink is contained in a cartridge. Alternatively, the pressurising member may be constituted by a pair of magnets provided at the side of the ink reservoir remote from the ink pool, the magnets being arranged to repel one another.
The switching circuit employed in the fountain pen may be constituted by a relay, a semiconductor device, or a combination of these elements. The switching circuit operates as follows. Upon receipt of a signal from the detector representative of the fact that the quantity of ink stored in the ink pool has decreased, the switch circuit causes the ink delivery device to supply ink to the ink pool. Upon receipt of a signal representative of the fact that the quantity of ink stored has increased, the switch circuit stops the ink supplying operation of the ink delivery device. Where the ink delivery device is constituted by an electromagnetic valve, the electromagnetic valve is provided with an iron core for opening and closing the opening of the ink reservoir, and an exciting coil actuating the iron core.
The electric source in the fountain pen may be an ordinary battery, a rechargeable battery, or a capacitor.
The pen may further comprise a writing-pressure-sensitive switch for sensing contact of the nib with a writing surface, the switch circuit being connected in series with the writing-pressure-sensitive switch. The writing-pressure-sensitive switch is activated by the writing motion of the pen, during which time the quantity of ink in the ink pool is detected by the detector and, as a result, ink is delivered under pressure to the ink pool. It is essential that the writing-pressure-sensitive switch be connected in series with the switch circuit or the detector so that, when the fountain pen is not in use, the delivery device is electrically disconnected from the electric power source so that consumption of electric power is suspended.
The writing-pressure-sensitive switch may be formed by providing one electrode on an end portion of the ink holder, and another electrode on a corresponding portion of the nib. Alternatively, the writing-pressure-sensitive switch may be formed by one electrode provided on the end portion of the ink holder or the nib, and another electrode provided above the ink holder. Also, a micro-switch may be employed as the writing-pressure-sensitive switch. Alternatively, the writing-pressure-sensitive switch may be constituted by a magnet provided on the end portion of the ink holder, and a reed relay positioned above the magnet in such a manner that the magnet operates the reed relay in response to writing motion of the pen. Moreover, a pressure sensor, such as a strain gauge or a piezoelectric element, may be fixed to the surface of the nib and thereby used as the writing-pressure-sensitive switch.
Preferably, the pen further comprises a cover provided on the surface of the slit region of the nib opposite the ink holder. The cover prevents the evaporation of ink from the nib. It is desirable that the cover be made of a soft film so as not lower flexibility of the nib.
Where the ink holder is an ink holding plate, it is preferable for the ink holding plate to be so positioned that a capillary ink pool is formed between the nib and the ink holding plate, the ink holding plate being made of an electrically non-conductive material, and the detector comprises the nib and an electrode provided on the surface of the ink holding plate.
Advantageously, the switch circuit includes means for controlling the delivery device in response to a quantity detection signal emitted by the detector. The means for controlling the delivery device may be any means which can operate. the delivery device so as to supply ink upon receipt of a signal from the detector indicating the fact that the quantity of ink has decreased, and to stop the delivery device to suspend the supply of ink upon receipt of a signal from the detector indicating the fact that the quantity of ink has increased. A Schmitt trigger circuit is most suitable, which, forming a hysteresis circuit, does not respond to slight variations of input signals from the detector, and can, therefore, eliminate fluctuations in the output.
In a preferred embodiment, the ink reservoir comprises an outer cylinder having a threaded portion on the inner surface thereof, an intermediate cylinder having a first threaded portion at one end thereof on an outer surface thereof, and a second threaded portion at the opposite end thereof and on the inner surface thereof, the first threaded portion of the intermediate cylinder being engaged with the threaded portion of the outer cylinder, and the second threaded portion of the intermediate cylinder being engaged with the threads of a rotatable threaded rod.
In another preferred embodiment, the ink reservoir comprises a flexible tube, a spring device including a spring plate extending longitudinally in the direction of the longitudinal axis of the fountain pen and a pushing member coupled to a central portion thereof, a short tube attached to a forward end of the spring plate with the pushing member disposed adjacent a side portion of the flexible tube, a collet rotatably coupled to a drive shaft of a motor, and a pressurising member comprising a shaft having a threaded portion at one end thereof threadably engaged with a threaded portion of the collet, the shaft having a non-threaded, small diameter portion at the other end thereof.
The ink delivery device may comprise a pressurising member disposed to punch upon the ink reservoir, the pressurising member being provided in a front cylindrical pen holder, and the pressurising member being operatively coupled to the output shaft of a motor provided in a rear cylindrical pen holder, the front and rear cylindrical pen holders being detachably coupled to each other, a key groove and an insertion hole being formed in the pressurising member, an output shaft of the motor passing through the insertion hole, a key member formed on the motor shaft and detachably engageable with the key groove, and a flexible tube disposed in the ink reservoir and positioned to be pushed upon by said pressurising member.
Alternatively, the ink reservoir may comprise a flexible tube, and spring means disposed laterally thereof, the flexible tube and spring means being disposed in a front cylindrical pen holder, in which case the ink delivery device may comprise a pressurising member including a threaded rod, a collet operatively connected to a motor shaft for rotation therewith and threadedly engageable with the threaded rod, a coil spring, a spring abutment member abutting one end of the motor shaft, the coil spring extending between the collet and the spring abutment member, the pressurising member, the collet, the spring and the spring abutment member being disposed in a rear cylindrical pen holder, a connecting cylinder connecting the front cylindrical holder to the rear cylindrical holder, a pushing ring formed on the connecting cylinder engaging a guide portion of the threaded rod and the outer periphery of the collet, the outside surface of the connecting cylinder being formed of a conductive material and the inside surface of the connecting cylinder being formed of an insulating material, a non-threaded, small diameter portion being formed on the threaded rod for permitting the collet to "free-wheel" at a predetermined position therealong, and a short tube disposed opposite the first-mentioned end of the threaded rod for pushing against the elastic tube in response to rotation of the motor shaft and movement of the collet. Preferably, the connecting cylinder is secured to the front pen holder, and the rear pen holder has a tip end in threaded engagement with the outer periphery of the connecting cylinder.
The fountain pen may further comprise magnet means coupled to move in response to a pressurising device of the ink delivery device, a reed switch being disposed to operate in response to movement of the magnet means, the reed switch being arranged to stop the ink delivery device when the magnet means reaches a predetermined position.
The fountain pen may also further comprise a micro-switch disposed so as to be activated in response to movement of a pressurising device of the ink delivery device, the micro-switch being arranged to stop the ink delivery device at a predetermined position thereof. In this case, current to the motor may flow through a front cylindrical pen holder which is electrically conductive, the front cylindrical pen holder having a portion fitted into a rear cylindrical pen holder, said portion being electrically insulating.
Advantageously, the fountain pen further comprises a contact-point switching mechanism arranged to control the flow of current from the electric power source to the ink delivery device, the contact-point switching mechanism being disposed such that electric current can flow only in a writing position of the fountain pen.
Seventeen forms of fountain pen constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is a part-sectional side elevation of the first form of fountain pen;
Fig. 1 a is a circuit diagram showing an electrical circuit employed in the fountain pen of Fig. 1;
Fig. 2 is a part-sectional side elevation of the second form of fountain pen;
Fig. 3 is a part-sectional side elevation of the third form of fountain pen;
Fig. 4 is an enlarged sectional view showing a modified form of a detector for use with the pens of Figs. 1 to 3;
Fig. 5 is an enlarged plan view showing another modified form of detector for use with the pens of Figs. 1 to 3;
Fig. 6 is an enlarged cross-sectional view showing modified forms of ink pool for incorporation in the pens of Figs. 1 to 3;
Fig. 7 is an enlarged cross-sectional view showing another modified form of ink pool for incorporation in the pens of Figs. 1 to 3;
Fig. 8 is a part-sectional side elevation of the fourth form of fountain pen;
Fig. 8a is a circuit diagram showing an electrical circuit of the fountain pen of Fig. 8;
Fig. 9 is a part-sectional side elevation of the fifth form of fountain pen;
Fig. 9a is a circuit diagram showing an electrical circuit employed in the fountain pen of Fig. 9;
Fig. 10 is an enlarged sectional view showing a part of the sixth form of fountain pen;
Fig. 11 is a part-sectional side elevation of the seventh form of fountain pen;
Fig. 12 is a plan view of a surface, on the ink pool side, of an ink-holding plate of the fountain pen of Fig. 11;
Fig. 13 is an enlarged cross-sectional view of part of the ink-holding plate of the fountain pen of Fig. 11;
Fig. 14 is a circuit diagram showing an electrical circuit employed in the fountain pen of Fig. 11;
Fig. 15 is a part-sectional side elevation of part of the eighth form of fountain pen;
Fig. 16 is a part-sectional side elevation of part of the ninth form of fountain pen;
Figs. 17 to 19 are part-sectional side elevations of part of the tenth form of fountain pen;
Fig. 20 is a part-sectional side elevation of the eleventh form of fountain pen;
Fig. 21 is a perspective view showing a spring member used in the fountain pen of Fig. 20;
Fig. 22 is a cross-sectional view showing parts of the collet and pressurising member of the fountain pen of Fig. 20;
Fig. 23 is a part-sectional side elevation of the twelfth form of fountain pen;
Fig. 24 is a cross-sectional view showing parts of the ink pool of the fountain pen of Fig. 23;
Fig. 25 is a cross-section taken on the line A-A of Fig. 24;
Fig. 26 is a part-sectional side elevation of the thirteenth form of fountain pen;
Fig. 27 is a side elevation of a collet and threaded rod used with the fountain pen of Fig. 26;
Fig. 28 is a transverse sectional view taken through the fountain pen of Fig. 26;
Fig. 29 is a part-sectional side elevation of the fourteenth form of fountain pen;
Figs. 30 to 32 are part-sectional side elevations of the fifteenth form of fountain pen;
Fig. 33 is a circuit diagram showing an electrical circuit employed in fountain pen of Figs. 30 to 32;
Figs. 34 and 35 are part-sectional side elevations of the sixteenth form of fountain pen;
Fig. 36 is a part-sectional side elevation of the seventeenth form of fountain pen;
Figs. 37 and 38 are diagrams of a position- sensitive switch used with the fountain pen of Fig. 36; and
Fig. 39 is a circuit diagram of an electrical circuit employed in the fountain pen of Fig. 36.

Referring to the drawings, Fig. 1 shows a fountain pen having an ink pool 1 formed by an ink holder 1 a made of a flexible plate material. Part or all of ink holder 1 a is rectangular, triangular or arcuate. The pen has a nib 2 having a slit region 4 extending from its pointed, writing end part way therealong. The ink holder has a tip 3 in contact with the slit region 4 at a position within about 5 millimetres from the point of the nib 2, and preferably within about 3 millimetres. The opposite end of the ink pool 1 is coupled to the front end portion of a cylindrical pen holder 5.
The ink pool 1 has a gap through which ink passes by capillary action to the nib 2. A detector 6 is provided in the ink pool 1, the detector being formed by a platinum contact 7 and the nib 2. The contact 7 is disposed close to the pen holder 5. A bellows-type ink reservoir 8 opens into the ink pool 1, an ink delivery device 9 being provided for transferring ink under pressure from the reservoir to the ink pool. The delivery device 9 includes a motor 10, and a piston 11 which is coupled to the output shaft of the motor, the piston abutting the reservoir 8. Fig. 1 shows schematically a switch circuit 12 and an electric power source 15 for the motor 10. As shown in Fig. 1 a, the motor 10 is connected to the detector 6 through the switch circuit 12 which is, for example, a latching relay. More specifically, the detector 6 is connected to an exciting terminal of the relay 12, while the electric power source 15 and the motor 10 are connected in series with the contact side of the relay 12. The pen holder 5 has a small diameter portion 13, which is adapted to hold the piston 11. A reduction gear 14 is provided on the output shaft of the motor 10, and a conductor 16 is provided to complete a current delivery circuit.
When no ink is present in the ink pool 1 between the contact 7 and the nib 2, the detector 6 will be an open circuit. As a result, the circuit connecting the electric power source 15 to the motor 10 is closed by the switch circuit 12 causing the motor to rotate. As a result, the piston 11 is moved forward, pushing against the ink reservoir 8, and causing it to supply ink to the ink pool 1.
When the ink pool 1 is supplied with ink, and an electrical connection is made between the contact 7 and the nib 2 through the ink, the detector 6 is a closed circuit, and the switch circuit 12 is opened. Thus, the connection between the electric power source 15 and the motor 10 is broken, thereby stopping the motor. Consequently, the supply of ink to the ink pool 1 from the ink reservoir 8 is suspended. In this way, ink is supplied to the ink pool 1 as ink is consumed, so that a predetermined quantity of ink is maintained in the ink pool at all times.
Sometimes a fountain pen is used after it has not been used for a relatively long time. In this case, with the fountain pen described above with respect to Fig. 1, the ink can be immediately made to flow by bringing the nib 2 into contact with the paper, because the tip 3 of the ink holder 1 a is positioned close to the end of the slit region 4 in the nib 2.
Fig. 2 shows a fountain pen having an ink pool, formed between an ink holder 1 a and a nib 2. This pen is similar to the pen of Fig. 1 and so will not be described in detail. Here, however, the detector 6, which is provided in the ink pool 1, is formed by a contact 7 and the ink holder 1a. Also, the delivery device 9 is formed by an electromagnetic valve 17 provided at the mouth of the ink reservoir 8, and a pressurising member, such as a spring 18, is provided at the rear of the reservoir 8. The electromagnetic valve 17 has an iron core and an exciting coil, thus forming a switch circuit.
When ink is emptied from the ink pool 1, a circuit connecting the electric power source 15 to the electromagnetic valve 17 is opened, as a result of which the electromagnetic valve is not operated. Accordingly, ink is pushed out of the ink reservoir 8 into the ink pool 1. When ink is supplied to the ink pool 1, the contact 7 is connected to the ink holder 1 a through the ink. Thus, the electromagnetic valve 17 is excited, thereby suspending the supply of ink from the ink reservoir 8 to the ink pool 1.
The fountain pen shown in Fig. 3 is again similar to that of Figs. 1 and 2. Here, however, instead of the spring 18 of the Fig. 2 pen, two magnets 19 and 20 are provided at the rear of the ink reservoir 8, and ink pools 1 are provided on both sides of the slit region 4 of the nib 2. The magnets 19 and 20 have their poles arranged so that the magnet 19 is repelled by the magnet 20, so that the magnet 19 is urged to the left (as seen in Fig. 3) against the ink reservoir 8. Here again an electromagnetic valve 17 is provided to control the flow of ink from the reservoir 8 to the ink pools 1.
Each of the pens described above has a detector 6 of the electrode type. However, various other types of detector may be employed, examples of such detectors being shown in Figs. 4 and 5. Fig. 4 shows an electrostatic capacity detector 6, one electrode of which is the nib 2, the other electrode being the ink holder 1 a which is electrically insulated. Fig. 5 shows a detector 6 formed of photo-electric elements. More specifically, the detector 6 is made up of a light-emitting element 21, a light-receiving element 22, and glass fibres 23 which are provided at predetermined positions outside the ink pool 1.
The ink holder 1 a may be in the form of a plate (as shown in Figs. 1 and 2), a housing (as shown in Fig. 3), a cylinder as shown in Fig. 6, or a feed as shown in Fig. 7. Fig. 6 shows a cylindrical ink holder 1 a having a hole 4a which communicates with the slit region 4 in the nib 2, the ink holder being fixed to the nib. In this case, the detector 6 is formed by a contact 7 provided in the cylinder 1 a and the nib 2. Fig. 7 shows an ink holder 1 a in the form of a feed which has a recess 24 confronting the slit region 4 of the nib 2. The ink holder 1 a is coupled to the nib 2, which is formed integrally with the front part of the pen holder. The ink pool 1 is provided in the slit region 4 of the nib 2. The detector 6 is formed by contacts 7 which are fixed to the nib 2 and the recess 24. The recess 24 communicates with the mouth of the ink reservoir 8.
Two forms of fountain pen which are provided with a writing-pressure-sensitive switch will be described with reference to Figs. 8 and 9. These pens are basically similar to the pens described above, and so will not be described in detail. Fig. 8 shows a writing-pressure-sensitive switch 25 having a first electrode 26a, which is provided at the end portion of the ink holder 1 a, and a second electrode 26b provided above the electrode 26a. The writing-pressure-sensitive switch 25 is connected in the circuit shown in Fig. 1 a, in series with the switch circuit 12, as shown in Fig. 8a. Fig. 9 shows a writing-pressure-sensitive switch 25 formed by the nib 2 and an electrode 26b provided above the ink holder 1 a. The writing-pressure-sensitive switch 25 is connected in the circuit shown in Fig. 1, in series with the switch circuit 12, as shown in Fig. 9a.
Fig. 10 shows a fountain pen which is similar to the pens described above, and so will not be described in detail. This pen has a feed similar to that of Fig. 7, but has a cover 27 covering one surface of the slit region 4 of the nib 2.
It will be apparent that each of the fountain pens described above is so constructed that an ink pool is provided in the slit region 4 of the pen nib 2, and ink is delivered under pressure into the ink pool 1 with the aid of the detector 6 provided in the ink pool. Thus it is unnecessary to provide an ink introducing path, so that a relatively large ink tank can be used, leakage of ink is prevented, the tendency for the user's handwriting to be irregular in density is eliminated, ink is maintained on the pen nib at all times,, and writing can be started smoothly and satisfactorily.
Fig. 11 shows a fountain pen having an ink pool 31 formed between an ink-holding plate 32 and the nib 33 of the pen, the gap between the plate 32 and the nib 33 is such that capillary action occurs therebetween. The ink-holding plate 32 is electrically non-conductive, and the ink pool 31 is communication with a slit region 34 in the nib 33. The end portion 35 of the ink-holding plate 32 is in contact with the slit region 34 within about 5 millimetres from the point of the nib 33, and preferably within about 3 millimetres.
A detector 36 is provided for detecting the amount of ink present in the ink pool 31, the detector being composed of an electrode 37 and the nib 33. The electrode 37 is provided on the surface of the ink-holding plate 32 which confronts the nib 33 through the ink pool 31 (see Fig. 12). The electrode 37 passes through the ink-holding plate 32, and extends along both sides of the ink-holding plate (see Fig. 13).
This pen has a pen holder assembly 38, which includes a neck 39, an intermediate pen holder 40, and a rear pen holder 41. The neck 39 is coupled to the nib 33 and to the ink-holding plate 32. The front part of the neck 39 is made of plastics material, a spring contact 42 being provided on the inner surface of the end portion of this front part. The spring contact 42 is connected through a conductor to the nib 33. The rear part of the neck 39 is made of metal, and is connected through a conductor to the electrode 37 on the ink-holding plate 32.
The intermediate pen holder 40 is detachably coupled to the neck 39, and is formed by a pair of telescoping cylinders, namely an outer cylinder 43 and an inner cylinder 44. The cylinders 43 and 44 are made of metal, and are insulated from each other by an insulating material 45 inserted therebetween. The inner wall of the inner cylinder 44 has an inwardly- extending protrusion 46. The rear end portion of the cylinder 44 protrudes outwardly from the outer cylinder 43 and has a threaded portion 47.
The rear pen holder 41 is also made of metal. A metal ring 50, having a threaded portion 49 on its inner wall, is mounted, via an insulator 48, on the intermediate pen holder side of the rear pen holder 41. The threaded portion 49 engages with the threaded portion 47 of the intermediate pen holder 40, so that the rear pen holder 41 is coupled to the intermediate pen holder 40. The rear pen holder 41 is provided with a rear cap 51.
An ink reservoir 52, which opens into the ink pool 31, is built into the pen holder assembly 38. The ink reservoir 52 includes a pipe 53, and a reservoir body 54 which is detachably connected to the pipe 53. A connector 55 is provided to connect the pipe 53 to the reservoir body 54, and to secure the pipe 53 to the neck 39. The reservoir body 54 is constituted by a metal cylinder 56, and a mouth 57 extending from the metal cylinder, the mouth being coupled to the connector 55. A rear plug 59 is fitted into the other end of the metal cylinder 56, the rear plug having therein a hole 58. A flexible ink-storing pouch 60 is coupled to the mouth 57, and is positioned within the metal cylinder 56. A follower 61 is fixed to the end of the ink-storing pouch 60.
Part of an electrical circuit is formed by connecting the spring contact 42 of the neck 39 and the protrusion 46 of the intermediate pen holder 40 to the metal cylinder 56 of the ink reservoir 52 in the pen holder assembly 38, as is apparent from the above description.
The pen holder assembly 38 includes a delivery device 65 having an electric motor section 62 and a piston 64 coupled to the output shaft 63 of the motor section, the piston abutting the ink reservoir 52. The motor section 62 includes an electric motor 66 and a reduction gear 67. The output shaft 63 of the motor 66 extends from the reduction gear 67, a threaded portion 68 being provided on the end of the shaft 63. The piston 64 has a threaded portion 69 which engages with the threaded portion 68. The piston 64 is positioned inside the shaft 63 of the motor 66 in such a manner that the end of the piston extends through the hole 58 in the ink reservoir 52, and abuts against the follower 61.
A battery 70 is provided in the pen holder assembly 38, the battery being connected to the delivery device 65 and the detector 36. The delivery device 65 and the detector 36 are coupled through a control device 71, which operates the delivery device 65 in response to an ink-quantity-detection-signal emitted by the detector 36. The motor 66 is connected through conductors to the metal ring 50 of the rear pen holder 41. The battery 70 is held in position by a coil spring 72.
A specific example of control device is a Schmitt trigger circuit (see Fig. 14). This circuit includes a capacitor C, a resistor R, a voltage comparator O2, a PNP type transistor 0₁, and protective diode D.
With the fountain pen of Figs. 11 to 14, when there is no ink between the electrode 37 in the ink pool 31 and the nib 33, the detector 36 is in the open state. As a result, the input voltage to the voltage comparator Q₂ decreases and, correspondingly, the output thereof decreases. Therefore, the transistor Q., is rendered conductive, thereby applying current to the motor 66 causing it to rotate. As the shaft 63 of the motor 66 rotates, the piston 64 and the follower 61 are moved forwardly, deforming the ink-storing pouch 60. The ink-storing pouch 60 is inflated outwardly upon being depressed by the follower 61. However, as the inflation of the pouch 60 is limited by the metal cylinder 56, the ink-storing pouch 60 is successively deformed from the end towards the mouth 57, without being twisted, so as to supply ink into the ink pool 31 at a suitable flow rate.
When the electrode 37 is connected to the nib 33 through the ink supplied to the ink pool 31, the detector 36 is closed. As a result, the input voltage to the voltage comparator O2 increases, and the output thereof also increases. Therefore, the transistor Q, is rendered non-conductive, the supply of current to the motor 66 is suspended, the motor stops, and the supply of ink to the ink pool 31 from the ink reservoir 52 is suspended. As the ink in the ink pool 31 is consumed, the nib 33 is disconnected from the electrode 37, and the detector 36 is opened again thus again supplying ink to the ink pool 31.
A number of modifications of the fountain pen of Figs. 1 to 14 will now be described. In each case, like reference numerals will be used for like parts of Figs. 1 to 10, though it will be appreciated that these modifications could also be to the embodiment of Figs. 11 to 14. Fig. 15 shows a modified pen having an ink pool 1 formed between the nib 2 and a flanged portion of the ink holder 1 a which is positioned to cover the slit region 4 of the nib. The ink pool 1 is in communication with the slit region 4. With this construction, the ink pool 1 has a capillary gap formed between the nib 2 and the ink holder 1 a, so that the same advantages accrue as with the earlier forms of pen.
Fig. 16 shows a modified pen whose ink holder 1 a is provided in the shape of a pouch. The ink holder 1 a forms the ink pool 1, and is disposed on the upper surface of the slit region 4 of the nib 2. Also, the outer surface of the ink holder 1 a is constructed of electrically conductive, flexible material 75, while the inner surface thereof is constructed of electrically non-conductive flexible material 76. When no ink is present in the ink pool 1, the pouch-shaped ink holder 1 a shrinks, thereby disconnecting the electrode from the nib. As a result, ink is supplied to the ink pool 1. When ink is supplied to the ink pool 1, the pouch-shaped ink holder 1 a expands, thereby connecting the electrode to the pen. As a result, the supply of ink to the ink pool 1 is suspended. Moreover, since the inner surface of the pouch-shaped ink holder 1 a is made of a non-conductive material, the ink is electrically isolated from the electric source, so that polarisation of the ink will not occur.
Figs. 17 to 19 show a modified pen having an ink reservoir constituted by a cylinder 77 and a multi-stepped piston 78. The piston 78 includes a threaded rod 79 connected to the motor (not shown), an intermediate cylinder 80 whose inner end is in threaded engagement with the rod 79, and an outer cylinder 81 whose inner periphery is in threaded engagement with the intermediate cylinder 80, and whose outer end is fixed to the cylindrical pen holder in such a manner that it can slide, but not rotate, therealong. When the motor rotates the rod 79, the intermediate cylinder 80 moves forward, the outer cylinder 81 being held owing to its engagement with the intermediate cylinder 80 which is non-rotatably fixed to the cylindrical pen holder. When the forward movement of the intermediate cylinder 80 is terminated (see Fig. 18), the outer cylinder 81 then moves forward owing to its threaded engagement with the intermediate cylinder 80 (see Fig. 19). In this regard, it is also possible to use a second similar stepped piston, whose outer cylinder engages the rod 79. The use of such a multi-stepped piston results in a shortening of the overall length of the fountain pen.
Figs. 20 to 22 show a modified pen whose ink reservoir 8 includes a flexible tube 83, a spring device 84 having a spring plate 85, a short tube 86 attached to the free end of the spring plate 85, and a pushing member 87 attached to the base of the spring plate 85, the pushing member being disposed to push upon the side of the tube 83. The ink delivery device of this pen includes a collet 88 connected to the drive shaft of the motor (not shown), and a pressurising member 89 having a portion thereof threadedly engaged with the collet. When the motor rotates the collet 88, the pressurising member 89 is advanced by a guide 90. The pressurising member 89 presses against the short tube 86, thereby bending the spring plate 85, as a result of which pressure is exerted on the flexible tube 83. Thus, ink is supplied to the ink pool under pressure, due to deformation of the flexible tube 83. After the advance of the pressurising member 89 is terminated, the collet 88 is returned to the position of a non-threaded, small diameter portion 91 of the pressurising member 89. As the flexible tube 83 can be sufficiently pressurised with only a slight movement of the pressurising member 89, the overall length of the fountain pen can be relatively short. Also, since the rotation of the collet 88 is not transmitted to the pressurising member 89 after the advance of the pressurising member is terminated, due to the presence of the non-threaded small diameter portion 91, damage to the motor and the pressurising member is prevented.
Figs. 23 to 25 show a modified pen whose ink delivery device is formed by a pressurising member 94 which pushes upon the ink reservoir, which is here provided in a front cylindrical pen holder 92. The pressurising member 94 is connected to the output shaft of the motor 10, which is provided in a rear cylindrical pen holder 93. The front and rear cylindrical pen holders 92 and 93 are connected together. The pressurising member 94 is provided with a key groove 97 and with a hole 100. The motor shaft 99 passes through the hole 100, and the pressurising member 94 is connected to a flexible tube 95. A key 98 which engages with the key groove 97, is provided on the motor shaft 99 within the hole 100. When the motor rotates, the pressurising member 94 also rotates, because of the engagement of the key 98 with the key groove 97. Upon rotation of the pressurising member 94, the flexible tube 95 is twisted, thereby delivering ink under pressure to the ink pool. When the ink is depleted, the rear cylindrical pen holder 93 is moved to the right of the position shown in Fig. 24. Then, as a result of this movement, the motor shaft 99 disengages from the pressurising member 94, so that the twisted tube 95 returns to its original state. The pen nib may then be dipped into an inkpot and ink sucked into the flexible tube 95. The rear cylindrical pen holder 93 is then moved to the left, and the key 98 on the motor shaft 99 is inserted into the key groove 97 in the pressurising member 94, so that the flexible tube is again pressurised. Thus, since ink is delivered under pressure by the twisting of the flexible tube 95, no advance of the motor shaft is needed, resulting in a shortening of the overall length of the fountain pen. Moreover, since the pressurising member 94 and the motor shaft 99 are provided in the front and rear cylindrical pen holders 92 and 93 respectively, and they are also detachably engaged with each other, supply and repeated pressurisation of the ink can be made by moving only the rear cylindrical pen holder 93.
Figs. 26 to 28 show a modified pen whose ink reservoir 8 includes a flexible tube 102, and a spring 121 provided in a'front cylindrical pen holder 103. Here, the pressurising member includes a threaded rod 117, a collet 110 which is connected to a motor output shaft 124 and is threadably engaged with the rod 117, a coil spring 115, and a spring abutment member 112 provided in a rear cylindrical pen holder 108. A connecting cylinder 118 is provided for connecting the front cylindrical pen holder 103 to the rear cylindrical pen holder 108. The connecting cylinder 118 is provided with a pushing ring 125 which engages the guide of the rod 117 and the outer periphery of a collet 116. The outside of the connecting cylinder 118 is formed as a conductor, and the inside thereof as an insulator. When the motor rotates, the collet 110 connected to the motor shaft 124 also rotates, thereby advancing the rod 117 guided by the connecting cylinder 118. At the same time, the spring abutment member 112 depresses the coil spring 115, and moves in the same direction as the rod 117. As a result, the rod 117 pushes on a short tube 105 of the ink reservoir 8, thereby to force ink from the flexible tube 102 under pressure. Moreover, as the rod 117 advances, the collet 116 reaches a non-threaded, small diameter portion 126 of the rod 117, as a result of which the collet 'freewheels'. After the ink is dissipated, the connecting cylinder 118 is moved to the right of the position shown in Fig. 26. As a result of this movement, the rod 117 disengages from the ink reservoir 8, so that the deformed flexible tube 102 and the spring 115 are returned to their original states. At this time, the pen nib may be dipped into an inkpot, and ink can be sucked into the flexible tube 102. The rear cylindrical pen holder 108 is then moved to the left, with respect to the connecting cylinder 118, and engagement between the collet 116 and the pushing ring 125 is released, thereby expanding the collet 116. As a result, the rod 117 is drawn into the collet 116 by the force of the spring 115. Thereafter, the rear cylindrical pen holder 108 is moved to the left, the collet 116 moves inside the pushing ring 125 and into engagement with the rod 117. Moreover, if the connecting cylinder 118 is moved to the left, so that the rod 117 comes into contact with the short tube 105 of the ink reservoir 8, the flexible tube 102 can be re-pressurised. Thus, by the use of the spring 115, the overall length of the fountain pen can be shortened. Furthermore, by moving the connecting cylinder 118 and the rear cylindrical pen holder 108, supply and repeat pressurisation of ink can be made.
Fig. 29 shows a modification of the pen of Figs. 26 to 28, this modification differing in that the connecting cylinder 118 is secured to the front cylindrical pen holder 103, and the rear cylindrical pen holder 108 has an end opening in threaded engagement with the outer periphery of the connecting cylinder. When the rear cylindrical pen holder 108 is rotated, it moves to the right from the position shown in Fig. 29. Consequently, the collet 110 provided in the rear cylindrical pen holder 108 and the motor (not shown) also move to the right, as a result of which the collet 116 expands, the rod 117 is drawn into the collet 116, and the supply of ink is supplemented the same as in the embodiment of Figs. 26 to 28. Also, if the rear cylindrical pen holder 108 is rotated in the other direction, the collet 116 advances and comes into engagement with the pushing rod, while the rod 117 further comes into contact with the short tube 105 of the ink reservoir, as a result of which the flexible tube 102 is re-pressurised.
Figs. 30 to 33 show a modified pen having a detector which detects the displacement of an ink-pressurising device 131 or of the ink reservoir 8, and in which the motor is stopped in response to a displacement detection signal produced by the detector. The end portion of the pressurising device 131, which pushes against the bellows of the ink reservoir 8, is formed by a magnet 130. A reed switch 128 is provided in the pen holder alongside the path of the magnet. In this case, a cylinder and flexible tube may, of course, be used rather than the bellows for the ink reservoir 8. Also, a micro-switch 132 (see Fig. 32) may be used instead of the reed switch. When the pressurising device 131 advances, upon rotation of the motor, and the magnet 130 attached to the pressurising device passes the reed switch 128, the reed switch is operated, thereby stopping the current supply to the motor. Thus, as the ink in the ink reservoir 8 is consumed, the motor is stopped, thereby preventing the consumption of electric power.
The pen of Figs. 30 to 33 may be modified as shown in Figs. 34 and 35. Here, the front cylindrical pen holder 103, through which the motor operating current passes, is an electrically conductive tube 134, and the portion of the front cylindrical pen holder which fits into the rear cylindrical pen holder 108 is insulated. When the motor rotates, the pressurising device 131 also rotates, because of the engagement of a key with a key groove (as was the case with the pen of Fig. 25). Rotation of the pressurising device 131 twists the flexible tube 135 thereby delivering ink under pressure. Also, by twisting the flexible tube 135, the pressurising device 131 is moved to the left from its position as shown in Fig. 34 and, when the magnet 130 of the pressurising device passes through the reed switch 128 provided in the front cylindrical pen holder 103, the reed switch is operated, thereby stopping the drive of the motor. After the ink is consumed, and the rear cylindrical pen holder 108 is moved to the right, the motor shaft then follows thereby to disengage the pressurising device 131 as a result of which the twisted elastic tube 135 is returned to its original state. Simultaneously, a cylindrical contact 136, which had been in contact with the insulated portion of the front cylindrical pen holder 103, moves with the rear cylindrical pen holder 108, disengaging from the insulated portion and then coming into contact with the rear cylindrical pen holder.
As a result, the cylindrical contact 136 and the rear cylindrical pen holder 108 are short-circuited and the motor is stopped. At this time, if the pen nib is dipped into an inkpot, ink can be sucked into the flexible tube 135. Moreover, if the rear cylindrical pen holder 108 is moved so that the key of the motor shaft is disposed in the key groove of the pressurising device 131, the flexible tube 135 may be repressurised. Thus, since the portion of the front cylindrical pen holder 103 which fits into the rear cylindrical pen holder 108 is insulated, and, as the motor has been stopped, re-engagement of the motor shaft and pressurising device 131 can be easily achieved.
Figs. 36 to 39 show a modified pen having a contact-point switching mechanism 138 of the type which can be engaged or disengaged in accordance with the angle of inclination of the fountain pen. Thus, the contact-point switching mechanism 138 includes an insulated capsule 139, two leads, and a body 140 of electrically conductive material. Mercury or a metal ball can be used for the body 140 of electrically conductive material. With this construction, electric power can be supplied only in a writing position, thereby preventing unneeded consumption of the electric power.

Claims

1. A fountain pen comprising a nib, an ink reservoir, means for transferring ink from the ink reservoir to the nib, an electric power source for powering the transfer means, and a detector for detecting the quantity of ink in an ink pool adjacent to the nib, the detector controlling the supply of power to the transfer means, wherein the ink pool is formed between the nib and an ink holder.

2. A fountain pen as claimed in claim 1, wherein the nib has a slit region.

3. A fountain pen as claimed in claim 2, wherein the ink holder covers the slit region of the nib, and the ink pool communicates with the slit region of the nib.

4. A fountain pen as claimed in any one of claims 1 to 3, wherein the nib is supported by a pen holder, and the pen holder houses the ink reservoir.

5. A fountain pen as claimed in any one of claims 1 to 4, wherein the transfer means comprises an ink delivery device associated with the ink reservoir, a power delivery circuit connecting the electric power source to the ink delivery device, and a switch circuit connecting the detector to the delivery circuit.

6. A fountain pen as claimed in any one of claims 1 to 5, wherein the ink holder is in the form of a plate.

7. A fountain pen as claimed in any one of claims 1 to 5, wherein the ink holder is in the form of a cylinder having a hole which communicates with the slit region of the nib.

8. A fountain pen as claimed in any one of claims 1 to 5, further comprising a feed, and wherein the ink holder is formed as a recess in a surface of the feed which confronts the slit region of the nib.

9. A fountain pen as claimed in claim 2, or in any one of claims 3 to 8 when appendant to claim 2, wherein the ink pool is provided on the upper surface of the slit region of the nib, on the lower surface of the slit region of the nib, or on both upper and lower surfaces of the slit region of the nib.

10. A fountain pen as claimed in any one of claims 1 to 9, wherein the detector comprises a single electrode or a pair of electrodes provided in the ink pool.

11. A fountain pen as claimed in any one of claims 1 to 9, wherein the detector comprises photo-electric elements provided at predetermined positions outside the ink pool.

12. A fountain pen as claimed in any one of claims 1 to 9, wherein the detector comprises an electrostatic capacity detector.

13. A fountain pen as claimed in any one of claims 1 to 12, wherein the ink reservoir comprises a bellows-shaped member, or a piston and a cylinder.

14. A fountain pen as claimed in claim 5, or in any one of claims 6 to 13 when appendant to claim 5, wherein the ink delivery device comprises an electric motor and a piston coupled to the output shaft of the motor for depressing the ink reservoir.

15. A fountain pen as claimed in claim 5, or in any one of claims 6 to 13 when appendant to claim 5, wherein the ink delivery device comprises an electromagnetic valve provided between the ink pool and the ink reservoir, and a pressurising member provided at the side of the ink reservoir remote from the ink pool.

16. A fountain pen as claimed in claim 15, wherein the pressurising member is constituted by a pair of magnets provided at the side of the ink reservoir remote from the ink pool, the magnets being arranged to repel one another.

17. A fountain pen as claimed in claim 5, or in any one of claims 6 to 16 when appendant to claim 5, further comprising a writing-pressure-sensitive switch for sensing contact of the nib with a writing surface, the switch circuit being connected in series with the writing-pressure-sensitive switch.

18. A fountain pen as claimed in any one of claims 1 to 17, further comprising a cover provided on the surface of the slit region of the nib opposite the ink holder.

19. A fountain pen as claimed in claim 6, or in any one of claims 13 to 18 when appendant to claim 6, wherein the ink holding plate is so positioned that a capillary ink pool is formed between the nib and the ink holding plate, the ink holding plate being made of an electrically non-conductive material, and the detector comprises the nib and an electrode provided on the surface of the ink holding plate.

20. A fountain pen as claimed in claim 5, or in any one of claims 6 to 19 when appendant to claim 5, wherein the switch circuit includes means for controlling the delivery device in response to an ink quantity detection signal emitted by the detector.

21. A fountain pen as claimed in claim 20, wherein the controlling means comprises a Schmitt trigger circuit.

22. A fountain pen as claimed in claim 20, wherein the controlling means comprises an electric circuit including a series-connected capacitor and resistor connected across first and second terminals of the electric power source with first and second terminals of the detector coupled across the capacitor, a comparator circuit having an input terminal coupled to the junction between the capacitor and the resistor, and a drive transistor having an input electrode coupled to an output of the comparator and an output electrode coupled to the ink delivery service.

23. A fountain pen as claimed in any one of claims 2 to 5, wherein the ink pool is formed between the nib and a flanged portion of the ink holder with the ink pool in communication with the slit region of the nib.

24. A fountain pen as claimed in any one of claims 2 to 5, wherein the ink holder is a pouch, and has an outer surface made of electrically conductive flexible material and an inner surface made of electrically non-conductive flexible material, the pouch having an opening communicating with the slit region of the nib.

25. A fountain pen as claimed in any one of claims 1 to 24, wherein the electric power source is a battery.