DE2552513A1 - INK REVOLUTION DEVICE ON AN INKJET PRINTER - Google Patents

Description

Böblingen, September 9, 1975 ki-fr

Applicant: International Business Machines

Corporation, Arinonk, N.Y. 10504

Official file number: New registration
Applicant's file number: LE 974 002

Ink circulation device on an ink jet 1 printer_

The invention is based on one in the preamble of claim 1
j given type of ink circulator.

It is, for example, by the laid-open specification 2 361 237
'known, the ink droplets generated by a nozzle, which for the _; Pressure is not required against an ink-collecting aperture too

from where it is directed back into the ink reservoir
will.

It is also known (laid-open specification 2 346 558) to sense various parameters of the ink of an ink jet printer and
from this, correction signals for regulating the ink pressure or the
Develop feed pump.

It is also known (IBM Technical Disclosure Bulletin Vol. 16 No. 10, March 1974, pages 3293 and 3294) that the ink level inside ; half of an ink reservoir to sense, with the ink as a Electrode of a variable capacitor is used.

It is the object of the invention specified in claim 1 to provide an ink circulating device that meets the special requirements' an inkjet printer is adapted and a high input

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reliability and high efficiency, with an ink refill container can be used in the simplest way in the ink circulation device and at the same time as an ink reservoir serves the facility.

Further features of the invention can be found in the subclaims .

Details of the invention are given below with reference to one shown in FIGS. illustrated embodiment described.

Show it;

Fig. 1 is connected to a magnetic card unit

Inkjet printer in which the inkjet; circulation device can be used,

FIG. 2 shows the ink jet print head of the type shown in FIG

_; showed inkjet printer with a co-j

I menacting grid, ι

; Fig. 3 Details of the ink circulator

recording inkjet printer,

Fig. 4 shows one in the ink circulating device

removable ink refill container,

Figs. 5a and 5b needles for piercing the in Fig. 4! showed ink refill container,

Fig. 6 is a diagram of the ink circulating device;

Fig. 7 shows a vent valve of the drawn in Fig. 6

neten bubble collector and

^LE974002 609827/0581

FIG. 8 shows a device in that shown in FIG. 6

used bellows pump.

The inkjet printer 1 is connected to a memory, for example the magnetic card unit 2, and has the keyboard 3. It also contains the inkjet print head 4, which can be moved back and forth in front of the paper 7 for the purpose of printing. The ink jet print head 4 has a nozzle and interacts with the grid 8, which is used to determine the position of the drops. The inkjet printer 1 is equipped with control buttons 10, 11, 12 and 13 for automatic printing, line feed, word and character printing. Other buttons 15 to 18 are provided for selecting the mode of operation, ie for recording, replaying, setting and jumping. The inkjet printer 1 also has the carriage return switch 31 and the right edge switch 32.

The magnetic card unit 2 has the loading slot 25, the bout marker 26, card eject button 27, track down button 28 ; and the track up button 29 for adjustment and sensing ! of the transformer in relation to the various tracks on the

j open card.

The ink jet print head 4 (FIG. 2) includes the pump 40 which Ink from feed line 41 is moved through crystal 42 to the nozzle. The crystal 42 is energized, i.e. H. with high frequency impulses on the order of 100 KHz applied to single ; To create drops. The ink droplets are ejected from the nozzle 43! And pass through the charging electrode 44 to correspondingly ■ to be charged with the output signal of a charging amplifier, whereby the drops in a column are deflected by a value, which corresponds to the vertical height of the drop point within a given character. As shown, there is the capital letter "S" designated by 50 from a number of

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vertical columns 51. The printing takes place in such a way that in side by side arranged vertical columns, each of which is one A plurality of drops, for example 40, may contain the nozzle 43 drops against the paper 7 (Fig. 1) for the printing of characters ejects. When the drops are not needed for printing, they are directed against the ink collecting aperture 53, from where they are is returned to the ink supply. A pair of baffles 60, 61 are in the path of travel following the charging electrode 44 the drop arranged. A constant, high potential prevails at the deflection plates 60, 61, which in cooperation with the different charges of the individual drops determines the size of the deflection of the drops moving against the paper 7 will. In the present case, the grid 8 is arranged horizontally instead of vertically, as shown in FIG. 1.

Referring to Figure 3, certain details of the ink jet printer shown in Figure 1 are illustrated. The keyboard is however in Fig. 3 has been omitted. The paper guide and transport device 70 has the roller 71, which is to be printed Paper carries. In reality, contrary to the illustration in FIG. 3, the paper guide and transport device is entirely in the Proximity of the printing unit 73 or the inkjet print head 4. The carriage 5 carries the inkjet print head 4 for the purpose of its movement from left to right and vice versa, in order to be able to print information on the paper carried by the roller 71. The ink refill container, referred to below as a cartridge, is shown in detail in FIGS. 4 and 6 shown. The cartridge 100 is mounted on the drive unit 75, which contains the drive motor 80, via various clutches and drive assemblies 81 and ropes 82, 83 is connected to the carriage 5 for its reciprocation.

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usually 170 g and only 113 to 170 g are used. 5 ^ 'g "':

are thrown away with the used cartridge. The cartridge 100 |

list near its base with two raised copper adhesive plates ^!

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105, 106 provided with a sensing circuit for the degree of filling j

LE 974 002

609827,

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LE 974 002

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809827 /

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In FIGS. 5a and 5b is one of the needles, for example the Needle 110 is illustrated. Each needle contains a sharp one Tip 110a for easy penetration of the septum 90 or 91. Ink circulation through the needle is achieved through the opening arranged in the circumferential surface of the needle 110b, which is connected to the longitudinal channel 110c.

The ink circulating device (Fig. 6) has the drive unit 75 attached cartridge 100 connected by lines 104a-g to pump 116 and nozzle 125, both of which are attached to the carriage 5. This represents the input side of the device, which also includes the bubble collectors 120, 122 the capillary tube 151, the main valve 154 and filters A, B and C contains. The return side of the device contains the inks catch plate 53, the drain and collecting pipe 115, lines 113a, b and the sieve 117.

The ink 116 passes through the needle 111 from the cartridge 100 and is conducted via the lines 104a, b and the filter A into the bubble collector 120 and from there via the line 104C into the further bubble collector 122 and then via the line 104d into the pump 116, from where it is fed to the nozzle 125 under pressure. The ink then passes through line 104e, capillary tube 151, line 104f, filter B, line 104g and main valve 154, which is switched on and off to control the flow of ink. From this main valve 154, the ink passes through the line 155 into the filter C and the line 156 into the nozzle 125. It is the task of the main valve 154 to prevent the ink from dripping out of the nozzle 125 and thereby contaminating other machine elements. The ink emerging from the nozzle and not required for printing is directed into the ink collecting diaphragm 53, where it flows off by gravity on the wall 126 of the drainage and collecting tube 115 into its elbow-shaped end piece 115a. From here \

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the ink becomes off via the line 113a, the screen 117, the line 113b, the needle 110 and that inside the cartridge 100 itself The standpipe 128 extending almost to its tip is sucked back into the cartridge 100. Sieve. 117 is between the lines 113a and 113b arranged for additional filtering and sifts out relatively large particles to ensure that there are no contaminants in the return path to the cartridge. The sieve 117 is a thin (e.g. 0.25 mm thick) film made of stainless steel, which is provided with a plurality of holes.

The ink is sucked into the return line by the vacuum, that is generated when the ink is removed from the cartridge by the pump 116 is sucked. When the amount of ink removed from the cartridge exceeds the amount directed against the ink-collecting nozzle 53, the ink level in the elbow-shaped end portion 115a of the drainage and collecting pipe 115 decreases, thereby allowing an air bubble is to enter the line 13b, whereby the pressure! ink used is compensated. While working at 'constant temperature is the ink level in the elbow-shaped End part 115a kept constant to allow enough air to enter to allow the return lines so as to be the ones required for printing Compensate for ink. The collecting container 133 is connected to the drain and collecting pipe 115 through two small openings 134, 135 [connected, one of which is located in the upper and the other in the lower part of the reservoir. The collecting container 133 sees j a space for the accumulated ink when the temperature expansion of the air in the cartridge 100 the expulsion speed · ^ corresponds to the ink in the cartridge. In this case, in

The cartridge does not create suction to return the ink to the cartridge, causing the ink to settle in the drain and collection tube 115 and will accumulate in the collecting container 133. The collective

Container 133 is so large that it can be used by the expected temperature range to be able to hold as much ink as possible. The collection container

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is made of a material 140, for example a loose foam, filled in to prevent the ink from splashing while the carriage 5 is moving. As mentioned earlier, the cartridge is 100 inserted into the receptacle 142 (Fig. 3), which the Cartridge on the needles 110 and 111 feeds.

The filter A can consist of a stainless steel woven mesh. It is used to remove small particles which could affect the pump 116, so that the filter A extends the service life of the machine. The filter B produces a further filtering on the way to the pump 116. Finally, the filter C arranged immediately in front of the nozzle 125 prevents the nozzle from clogging. Usually the contaminants are held in the various filters during the life of the machine.

The bubble collector 120 prevents the filter A from passing through air ! is blocked. Since the ink is sucked out of the cartridge 100, pressure differences form small air bubbles in the stream that try to accumulate on the left side of filter A (Fig. 6) and thereby block the flow of ink. To do this

! prevent, the upper part 120a of the bubble collector 120 is provided. Thus, the bubbles 121 in the ink can rise and accumulate in the uppermost portion of the upper part 120a. The bubble collector 122 acts in a similar way. The bubble collectors j 120, 122 are equipped with valves 160, 161, which have a periodic Enable maintenance of the bubble collectors by releasing the air bubbles collected in them! A suitable one for this purpose The valve is shown in Fig. 7 and includes the valve seat 165 against which the valve disc 166 of resilient majterial 168 is applied under the action of the spring 167. The connection

Formation of a line with the neck 170 and the creation of a vacuum during the maintenance process overcomes the tension the spring 167, whereby the valve disc 166 with its resilient

jbigem material 168 can move to the right (Fig. 7) and 'Thus, the air is allowed to exit the bubble collector.

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The shutoff valve 102 is between the cartridge 100 and the filter A arranged for a compensation of the conditions in the Bubble collector 120, the line 104b, the bubble collector 122 and the Pump 116 occur. This is provided as the in the top The air in the bubble collector 120, for example, has a vacuum of approximately the same amount as in the pump feed line 114. If the shut-off valve 102 were not present, the vacuum in the bubble collector 120 would have dropped through Entry of air into the needle 111 upon removal of the cartridge 100 from its receptacle 142. The next time a cartridge 100 had to be removed, it would be in the bladder collector 120 will be even larger than the previous time, which is a cumulative process that increases after each cartridge replacement. In order to avoid this, the shut-off valve 102 prevents the ingress of air into the Line 104b. The shut-off valve 102 closes before the needles 110, 111 are removed from the cartridge 100. When a new cartridge 100 is inserted, the needles 110, 111 penetrate the bottom of the cartridge, whereupon the shut-off valve 102 opens.

Any pump that fulfills the intended function is suitable as pump 116, but a bellows pump is an example (Fig. 8) .shown. The ink enters the pump through line 104d and exits through line 104e. The pump

■ holds flap valves 180, 181, the pump bellows 182, the return ! spring 183 and the magnetic part 184, which are held together by support elements 186-190.

The main valve 154 (FIG. 6) is intended to prevent the dripping of ink after closing and during start-up. With the main valve 154 is connected to the parallel channel 162, which is the vent

163 owns. The parallel channel 162 connects the main valve kit to the collecting container 133. The vent 163 is therefore provided, since in some cases the ink level in the drain and collection tube 115 can be so high that the collection container 133 is filled and an ink film is formed at the upper opening 134

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that could interfere with the pressure conditions. There are also cases possible in which insufficient positive pressure is generated sufficient to break through the ink film covering the upper opening 134 , thereby allowing the ink in the drain and collection tube 115 to have a higher level than normal and the ink collecting aperture 53 splashed and thus the function of the printer could be impaired. The vent 163 allows air to escape from the same or from the drain and manifold 115 depending on which location is more convenient under the current conditions.

In the following description of the operation of the ink circulating device, the cartridge 100 is located on the needles 110, 111. The initial vacuum in the cartridge 100 sucks the ink-collecting diaphragm 53 free of ink and via the lines 113a and 113b through the sieve 117. This usually also creates air through the i

Return line sucked in, whereby a ^! atmospheric pressure.

The pump 116 then begins to operate and the main valve: til 154 opens. At this point there is no vacuum! in the return lines, which include lines 113, 113b

eat. However, a vacuum is created when ink in the catcher 53 falls into the elbow-shaped end portion 115a of the drainage and collection tube 115 and fills the same up to its control point 115b. When this occurs, air can no longer reach the cartridge 100, creating a vacuum therein. The vacuum within cartridge 100 continues to build, and after about 30 seconds the flow of ink in return lines 113a and 113b and pump lines 104a-104d reaches an approximate equilibrium. The ink in the drain and collection tube 115 will also attempt to flow into the sump 133 during this 30 second period. Such states and ink levels are maintained until the start of printing.

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Because ink gets into the ink-collecting aperture 53 during printing , it falls against control point 115b. When the pump 116 sucks more ink from cartridge 100 than into the return line can flow, the ink level falls at the control point 115b and air enters the cartridge 100. This causes the vacuum in the cartridge 100 to drop slightly, causing the backflow to flow into the cartridge 100 is slowed down and the ink level rises again at control point 115b. Thus, control point 115b is the only point allowing air to flow back into the cartridge 100.

In the Gesarat version it is mandatory that the control point 115b is arranged lower than the collecting container 133. To the taking place under the influence of gravity ink flow to To enable control point, it is necessary to have a vent; to control point 115b is maintained by keeping the Drainage and collecting pipe 115 and the ink supply orifice 53.

The aforementioned conditions are maintained during operation until the pump 116 is switched off near the end of printing. It should be noted that ink flows continuously between the main valve 154 being turned on and off. After the [main valve has closed 154, ink continues to flow in the return lines 113a and 113b. This happens because a vacuum is created in the cartridge 100 which tries to suck the ink through the return line until a state of equilibrium is reached.

The tip of the needle 110 should be higher than the highest point of the ink level expected in the drain and collection tube 115 or in the collection container 133, in order to prevent ink from overflowing from the line system if the cartridge 100 is removed. To completely prevent this, the shutoff valve 192 can be provided. In this case the amount is the ^! Needle point 110 unimportant.

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j The vacuum in the cartridge 100 depends essentially on both the difference between the standpipe 128 in the cartridge 100 and from the control point 115b, which in a special case can be 101 mm of mercury acid, as well as from the pressure drop in the Return lines 113a and 113b. In some cases it is effective Vacuum in the cartridge 100 is slightly less than 508 mm of mercury.

When the ink in the cartridge 100 is exhausted, the concentration tries increase as a result of their contact with the air on the way from the nozzle 125 to the ink-collecting orifice 53 and with the Air in the drain and collection tube 115 and in the reservoir 133. As the concentration increases, the viscosity also increases and ί the pump 116 can no longer maintain the pressure, - the j is necessary for the ink to disintegrate into individual drops j for the purpose of pressing or returning through the inks--!

i orifice. Thus, a suitable servo system, such as e.g. wise from the OS 2 346 558 described above, to provide to increase the pump pressure, which is an upright-j obtained the pump drive to a suitable level.

When the ink in the cartridge 100 has dropped to about 56 g the cartridge should be replaced to avoid difficulties due to its very increased concentration.

j Alternatively, it may be desirable to include additional filters in the ! To provide cartridge 1OO itself. In this case, the! Throwing away the cartridge 100 also includes those collected by the cartridge filter Removed impurities.

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Claims (1)

PATENT CLAIMS Ink circulation device for an inkjet printer, in which ink is conveyed from a reservoir to at least one nozzle by means of a pump, which ejects ink droplets, which are electrically charged and, depending on their charge, deflected either onto corresponding points on the paper or into an ink collecting aperture, which is used for printing returns drops that are not required to the reservoir, characterized in that an exchangeable ink refill container (100) when inserted in its receptacle (42) forms the reservoir as an integral part of the ink circuit that is fed into the feed line (104a-g) for the nozzle (125 ) the pump (40 or 116) is used - to achieve a certain line pressure on the one hand at the nozzle {125} and on the other hand in the. Reservoir generate a certain vacuum zn and that in the return line {113 a, b) for the ink drops not required for printing between the collecting aperture (S3) and the reservoir (10O) a pressure compensator <115a) is arranged for regulating the return of the Ink in the reservoir C 100 J while maintaining the vacuum in the ren. 2, ink circulation device according to claim 1 _r, characterized in that between the pump (116) and the reservoir Π00) and between the pump (1T6X and the nozzle <125) filters (A, B ^ C) are arranged that also in the Collecting orifice {53) and the return line <113a, b) connecting the reservoir C 10O) there is a filter {117) and that several air bubble collectors - {- 12O, 122) are inserted in the feed line (104a-g). 3. InksuBiwaizeinriehtung according to claim 1 _1, characterized in that the ink refill container <100) consists of a housing closed by a plug {1Ο1) LE 974 OO2 609827/0581 and that in the plug (101) there are two openings, each closed by a thin partition (90, 91), which each with a septum piercing and arranged in the receptacle (142) for the refill container (100) Needles (110, 111) cooperate, of which one (110) with the feed line (104a-g) and the other (110) is connected to the return line (113a, b) and that the opening in the plug (101) connected to the return line (123a, b) extends up to the upper end of the
Refill container (100) extending standpipe (128) picks up. 4. Ink circulating device according to claim 1 and 3, characterized
characterized in that an extension (103) is arranged on the housing of the refill container (100), which with a
Closing valve (102) in the feed line (104 a, b) cooperates in such a way that it closes when the refill container (100) is removed from its receptacle (42), namely before the two needles (110, 111) are assigned to them
Leave the partition walls (90, 91). 5. ink circulating device according to claim 3, characterized in that that on the housing of the refill container (1O0) in the vicinity of its base two copper plates (105, 106) are arranged with a capacitive filling level sensing circuit cooperate. 6. ink circulating device according to claim 3, characterized in that that the refill container (100) has a predetermined ink pressure to after its insertion in its receptacle (142) to generate an initial vacuum. 7. ink circulating device according to claim 1, characterized in that in the feed line (104g) between the
Pump (116) and the nozzle (125) a main valve (154) is arranged, which is opened when the inkjet printer is started up. LE 974 OO2 609827/0581 8. ink circulating device according to claim 2, characterized in that that the Blasensairunler (120) from a housing which is divided into two parts by a filter (A), the one connected to the refill container (100) Part of the housing for receiving air bubbles (121) is higher than the maximum ink level. 9. ink circulating device according to claim 8, characterized in that that the bubble collector (120) has a vent valve on its housing part connected to the refill container (100) (160) carries. 10. Ink circulation device according to claim 2, characterized in that that in the return line (113a) between the filter (117) and the refill container (100) a shut-off valve (192) is arranged. 11. Ink circulation device according to claim 1, characterized in that that the ink collecting diaphragm (53) merges into a vertical tube (115) which is elbow-shaped at its lower end (115a) is formed, wherein the leg adjoining the elbow (115a) is connected to the return line (113b), and the elbow-shaped Section (115a) as a control point for the passage of ink and for maintaining the vacuum in the reservoir ^ serves.
(100) 12. Ink circulation device according to claim 11, characterized in that that the vertical tube (115) of the collecting diaphragm (53) through two openings (134, 135) with a collecting container (133) is connected to collecting excess ink resulting from temperature changes and that this collecting container (133) is filled with a loose foam (140). LE 974 002 609827/0581 13. Ink rolling device according to claim 12, characterized in that that the collecting container (133) is equipped with a vent (163). 14. Ink circulation device according to claim 1, characterized in that that the ink reservoir (100) is arranged stationary and the pump (40 or 116) with the ink jet print head (4) and the collecting container (133) attached to a carriage (5) which can be moved back and forth in the direction of the rows are. LE 974 002 609827/0581 Blank page