JPS58168571A - Ink supply system for ink jet head array - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ink supply systems for inkjet printers, and more particularly to an ink supply reservoir that acts as a static pressure regulator for ink entering the inkjet of an inkjet printer's printhead.

The normal resupply mechanism for replacing ejected ink is based on capillary action and the ink supply pressure is
Impulse inkjet printers (impulse inkjet printers) require special ink supply requirements, as they must be within the capillary pressure that can be generated by the nozzles.

Because the ink reservoir is typically connected to the printhead to provide a low supply hydrostatic pressure, this system is susceptible to pressure surges generated by inertial printhead or supply line operation. .

Therefore, it is desirable to keep the ink supply at the same relative level as the printhead's ink jets even as the printhead moves. Ink supply systems used in the past have generally been bulky, making it difficult to match the ink supply system to the movement of the printhead to maintain the pressure requirements necessary to provide the desired printing characteristics. Historically, the typical configuration of impulse inkjet printers has been to provide multiple droplet firing devices connected to a similar ink supply system. For some existing systems, which are large volume inkjet systems, linking the recirculation system to the ink supply system (9) and locating a large ink supply container can further reduce the need to maintain the necessary pressure requirements. increase the difficulty. Hitherto, as a result of these drawbacks, it has been necessary to separate the individual infusier devices from each other so that they can operate independently. Additionally, all inkjet printing systems operate best when there is no air or gas in the ink supply system lines or printheads. This requirement is particularly demanding for impulse printers. This is because air bubbles interfere with the incompressibility of the liquid and prevent the impulse mechanism from operating properly. Various methods have been proposed to solve this problem, such as providing a special chamber for the air bubbles before they reach the printhead, or removing air from the ink supply system before it is used. Ta. However, in their current configuration, these methods
It requires additional complex system adjustments which completely negates the effectiveness and compactness of inkjet printers. Additionally, in many conventional inkjet printers, the systems, especially the ink supply systems, are generally bulky and therefore must be located in a vertical location remote from the printer. Due to the fact that each printhead must be uniquely matched. This makes adjustments such as printhead replacement difficult and expensive, limits the movement of the printhead within the system when desired, and further reduces the accuracy of the inkjet printer.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ink supply stem for an inksheet printer which overcomes the aforementioned drawbacks.

Another object of the present invention is to provide an ink supply system for an inkjet printing device that acts as a static pressure regulator for the ink being pumped during the inkjet of each printhead.

Another object of the present invention is to provide a compact ink supply system that reduces the mechanisms necessary to keep the ink being applied to the printhead at the same relative level as the inkjet.

Another object of the present invention is to provide an ink supply system that allows the use of large capacity ink containers that can be located remotely from the printhead of an inkjet printer.

Another object of the present invention is to provide an ink supply system that can provide a Rin/Kujitsu array at approximately the same height and that can also function as a single inkjet.

The foregoing and other objects generally relate to at least 1-7 of impulse droplet inkjet printers.
This is achieved by the present invention by providing an ink supply system in fluid communication with two printheads. The ink supply system includes a primary ink source that supplies ink to a secondary ink supply container. This 2
The ink supply serves as a temporary storage container that provides ink at a constant static pressure to the printhead of an inkjet printer. This secondary storage container has a low height pro, f i with a flexible thin film forming a sealed hole surface around its periphery to prevent ink leakage.
l e) Contains a cup-shaped configuration with a diameter ratio. An air release valve is provided to allow the reservoir to be filled with ink. The flexible membrane that wraps around the top of the secondary storage container has a small reflective spot in its center.

This reflective spot
and provides a level sensing mechanism for sensing the ratio of the liquid level within each storage vessel. The sensitivity of this level detection mechanism operates a suitable valve or pump that allows the secondary reservoir to be filled in the manner described below. The secondary reservoir is connected to the ink 2T-print print head in such a way that a constant level is maintained between the two.

In the present invention, an inkjet printer can be effectively operated with an ink supply system having a secondary storage container with a level detection mechanism to maintain the ink at a proper level within the storage container, where the secondary storage container IFr 'r ”4
It is understood that it functions as a manifold that supplies T-.1/ri to the print-rad nozzle (13). The compactness of the reservoir simplifies the mechanisms required to hold the reservoir at the same relative level as the inkjet head when the inkjet head is operated. This allows the storage container to be placed in close proximity to the print-\rad. By having a secondary storage container according to the present invention, a large primary ink container can be located remotely from the inkjet head.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit diagram representing the ink supply system of the present invention. A primary ink source 1 supplies ink to a secondary or temporary ink supply reservoir lO and an inkjet printhead 20. Pump 2 supplies ink based on commands from primary ink source 1 and conveys it through filter 3 to secondary storage container IO. Secondary storage container I
O then supplies ink via conduit 16 to inkjet printhead 20 . Ink from primary source 2
Suitable means can be used for transporting to the next storage container. The means shown in the figure takes the form of a 1R peristaltic pump that advances the ink to a secondary storage container, and when the pump is not in operation, a portion of the piping within this pump acts as a barrier to remove the ink. Compressed to prevent backflow. This pump typically operates with low volume excursions on the order of 0.25 m/min.

However, other means, such as dynamic feed systems,
It can be used to transport from a secondary source to a secondary storage container. The filter removes residual molecules that corrode the inner tube walls of the pump. The filter pores are generally smaller than about 10 microns. The filter itself is in the form of a replacement cartridge that can be easily replaced. Quick-disconnect attachment 4 with knobs on both sides provides dual 7-holes and two for filling or maintenance without loss of ink or ingress of air.
Then the storage container and inkjet printhead can be removed. The secondary storage vessel IO functions as a manifold or central ceiling for the inkjet printhead or nozzle array 20. Built-in manual valves 5 allow individual heads to be disconnected during maintenance, transport, head operation or for air venting.

The secondary or temporary storage container 10 has a low height (pro, file) diameter with a thin plastic membrane 11 loosely glued on its top but rounded to prevent ink leakage. , containing a cup-shaped structure of the ratio. An air release valve 12 is provided to ensure that the storage container is filled. This film, which is generally about 1 ml thick, is made of polyolefin or polytetra (polytetra), which does not chemically react with the ink used.
Fluoethylene) and other polymers such as fluoroethylene (fluoroethylene), etc. The flexible membrane 11, which serves as the top housing for the secondary ink reservoir, has a small reflective spot in its center. An access device in the form of a level sensing mechanism 14 is placed just above the flag height of the reflective spot of this flexible membrane. This level detection mechanism 14 includes light emitting diodes (LE, D) and a phototransistor that detects changes in the liquid level. However, it is within the scope of the invention that other types of level detection mechanisms may be used. For example, there are detection mechanisms based on capacitive coupling, magnetic proximity sensors, or other forms of optical detection means using incandescent lamps as light sources and photodiode photodetectors. Determine the amount of light.When this membrane is at its lowest point,
The signal operates the pump to fill the reservoir.

If this rumor fails to return to maximum height within a predetermined time, indicating a failure within the film or an empty ink supply system, a signal is activated.

However, the initiation of a low ink signal does not prevent continued operation of the printer. There is still enough ink remaining in the reservoir to supply the inkjet for an additional time period, the length of which depends on the volume of the secondary reservoir.

The transparent protective cover 15 covers the flexible membrane 1 of the storage container 10.
It is installed in the first part of the room. This cover serves to physically protect the flexible membrane (1'7) and also prevents the membrane from being overstretched, especially during inkjet line venting (described below). do. Thus, the protective cover 15 covers the top 1/32'' of the flexible membrane 14 when the membrane is in its normal surface position.
It is located at

The secondary storage container is mechanically affixed to the printer's inkjet printheads within one printhead arrangement or within an inkjet print array. This mechanical attachment ensures that the position of the reservoir is fixed at the same level relative to the inkjet printhead, thereby allowing a constant static pressure to be maintained within the system. An unwanted constant flow of ink occurs when the reservoir is placed above the orifice of the inkjet nozzle.

When the reservoir falls substantially below the orifice, a backflow of ink toward the reservoir occurs. In this explanation,
The miniscus of the secondary storage vessel is maintained between 1 and 2 inches below the level of the orifice of the inkjet nozzle. In operation, ink is drawn from the secondary storage calyx to the inkjet orifice by capillary action.

Pump approximately 0.01 to 0.5111//7717:
? The secondary storage container is slowly filled with a speed of Z, and the printing by the inkjet print head is H゛,<.

The ink supply structure of the present invention is 0.01-0.5 mi/
The flow velocity (about] O
By pumping ink through this system at .me/min), the inkjet printhead carpet. The container fills quickly and ink can continue to flow through the inkjet array. In normal printing operations, the charge ink pumped into the secondary reservoir fills the reservoir without venting the head. This is because the pressure required to fill the reservoir and deflect the flexible membrane is much less than the pressure required to flow the inkjet orifice. Protective cover 1
5 prevents the flexible membrane from being overstretched during the air-bleeding operation, thereby preserving the integrity of the membrane (19).
) One. If the membrane can be stretched and therefore stretched and deformed,
This film hits and covers the optical sensor, resulting in a constant lack of ink signal and does not return to its original shape. The aforementioned manual valve 5 provides the ability to selectively disconnect and bleed the inkjet head.

In FIG. 2, the electronic control system is shown.

A supply reservoir 30 containing ink 81 is placed below an access device consisting of a light emitting diode (LED) 41 and a phototransistor 42. The access device is the diaphragm or membrane 83 of the flexible/pull ink storage container.
A white reflective dot 32 is located in the center of the screen. Since the dots on the diaphragm F move up and down with the ink level, the photo lancet receives more or less reflected light. This light imparts a base current in the phototransistor, proportionally turning it on or off and thus lowering or increasing the collector voltage. When the storage vessel is filled, the collector voltage is at its lowest and increases gradually towards the source voltage (m) as the inflation (20) level decreases. The collector voltage is input to a pair of It comparators 4,8A and 4,8B with variable reference voltage inputs.As long as the input voltage is less than the reference voltage R, the output R will be high and the storage Indicates that the container is full.

Since the detector output changes with the ink level, the maximum ink level is at the reference voltage. This can be adjusted by adjusting the pressure B.

Comparator A functions similarly to detect low ink levels. When input 11 voltage is 1- below reference voltage A (above voltage B, output B is off), output A will be high indicating a low ink level. The outputs of the two comparators are provided in set/reset flip 70 4,4.

When the ink level reaches the lowest level, comparator B detects the level and sets the flip 70 tip. This flip-flop then turns on the ink supply pump motor.

output? Since it is J-latched, no hysteresis is required on the comparator.

(21) The continuously circulating clock 52 is sent to the counter 5]. The normally associated reset line of counter 51 is not energized while the reservoir is being filled by pump motor 58. If the reservoir is not filled within a set time period, the counter counts up to its maximum value. When the counter reaches its maximum value, no ink output signal is generated.Since the diode shunts the counter and provides the counter output to its input, no further clock pulses are received and no ink signal is generated. is retained.

The ink supply system of the present invention was implemented in an inkjet printer having multiple inkjet printheads. Each inkjet printhead has approximately 10-1. It has multiple inkjet orifices consisting of 2 orifices. For purposes of illustration, these, typically seven, inkjet heads will be considered as an array.

The volume of the secondary ink supply storage container is calculated by the following formula (22) It is determined.

V-πA, < Rz-K) where: h - Flexible membrane deflection height R - Storage vessel radius A typical storage vessel of approximately 2 inches diameter with a flexinople membrane with a total deflection of 1 inch is: It allows continuous operation for about 30 minutes. This is approximately 6.5m based on the above formula.
A storage container with a volume of 1 is required.

The use of the temporary storage container of the present invention is primarily intended for capturing impulse inkjet arrays at approximately the same height. However, the temporary reservoir also functions as a single impulse inkjet where extended ink fill intervals are desired. The compactness of the reservoir simplifies the mechanisms required to hold the reservoir at the same relative level as the ink/jet when it is moved. In this way, the reservoir can be placed in close proximity to the inkjet.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the ink supply nostem of the present invention, and FIG. 2 is a circuit diagram illustrating the electrical response obtained as a result of the operation of the level detection mechanism of the present invention. ■=Primary ink source 2: Pump 8: Filter 4. : Separation attachment 5: Manual valve 10: Secondary storage container 11: 7 Rexoplu thin film 12: Air vent valve 18: Reflection spot 1Φ:
Flexible membrane 15: Transparent protective cover 16: Conduit 20: Ink sheller)・Print head patent applicant
Bitney Bowes Inc. Juku? ,, YoriN Behachi
Upper range~-/10h~
1st angel - ~gi I■9 HQ? A Φ −＼ K (X 7 1 10 + 1 ・1" coffin-like 1 haze

Claims (1)

[Claims] (1) 1 for impulse type inkjet bling
a secondary ink supply container, a secondary ink supply storage container communicating with the primary ink supply container and receiving ink from the primary ink supply container;
a level detection mechanism juxtaposed above the secondary ink supply storage container for detecting a change in the level of liquid in the secondary storage container; a supply system for an impulse-type inkjet printer, comprising means for directing the head to the head. (2) An ink supply nostem for an impulse-type inkjet printer according to (1), wherein the secondary ink supply reservoir includes a flexible j1ψ forming an upper surface thereof, the membrane having a reflective spot at its center. (1) In (8) and (2), the level detection mechanism comprises a light emitting diode and a phototransistor, and in response to movement of the flexiple membrane, the level detection mechanism is responsive to the movement of the flexiple membrane and the reflective spot in the secondary ink supply reservoir. An ink supply system for impulse type inkjet printers that detects changes in liquid level. (4) The seven ink supply stems for an impulse type inkjet printer according to (1), wherein the flexible membrane is protected by a transparent cover. (5) The ink supply system for an impulse type ink/jet printer according to (1), wherein the secondary ink supply storage container further includes an air vent valve. (6) In (1), the ink supply system for an impulse inkjet printer further includes a secondary storage container ((ink, i.e., a pump for delivering a writing liquid). (7) In (6), the pump is a peristaltic pump. An ink supply system for an impulse type inkjet printer. (8) In (6), there is further provided a filter that can be replaced during maintenance between the pump and the secondary storage container.
2) - An ink supply system for an impulse type inkjet printer including a cartridge. (9) The method of (1) further includes a quick disconnect valve disposed between the primary ink supply source and the secondary ink supply source, the disconnect valve controlling the flow of ink between the ink supplies. 11111L, an ink supply system for an inkjet (.00) with a flexible thin film on the upper surface that provides a dual nodal system that allows the secondary storage container to be disconnected from the primary supply source. low height,
a cup-shaped structure with a diameter ratio, a level detection mechanism disposed on the structure to detect a change in the level of a liquid in the cup-shaped structure, and supplying the writing liquid to an inkjet print head as required. a storage container for controllably introducing a writing liquid into an impulse-type inkjet printer. (11) The storage container of (,10) further comprising a transparent protective cover on the flexible membrane, the flexible membrane having a reflective spot at its center. (]2) At least one i/c route (
3) an ink supply system comprising at least one inkjet printhead having a filter; a primary ink supply; and a secondary ink supply reservoir receiving ink from the primary ink supply; an inkjet printer comprising: a level sensing mechanism disposed in said storage container for detecting changes in liquid level in said storage container; and means for delivering ink from said secondary storage container to each of said inkjet printheads. An inkjet printer in which each inkjet printhead has 10-12 orifices in the decoy (12). 0(1) (13) In an inkjet printer O (L'5) (12) comprising a play of seven inkjet printheads, the secondary ink supply reservoir is a flexible membrane with a reflective spot in its center. as its upper surface. (to) In (15), the level detection mechanism comprises a light emitting (4) diode and a phototransistor, and a storage for detecting a change in level of the liquid in the secondary ink supply storage container together with the single reflective spot. container. Q7) The storage container of (1, 2), wherein the ink supply system further includes pumping means for pumping ink from the primary storage container to a secondary storage container. Q8) The storage container according to (17), wherein the pump means is a peristaltic pump. (19) The storage container of (1, 2), wherein a manual valve is provided for connecting each of the means for conveying ink from the secondary storage container to each inkjet printhead. (a) a primary ink supply source, a secondary ink storage container, pump motor means connected to the primary ink supply source for pumping ink from the supply source to the secondary storage container, and the secondary ink storage container; detecting the level of ink in the storage container in response to a level of the ink in the storage container and causing pumping of the pump motor means when the level of ink in the storage container falls below a predetermined value; (5) control means, wherein the pump motor means does not pump the ink into the secondary storage container when the level of the ink in the secondary storage container is equal to or greater than a predetermined value; An ink supply system for supplying ink to an inkjet printer, wherein the control means stops pumping of the pump motor means when the level of the ink in the reservoir is substantially equal to or greater than the predetermined value. (21) In (20), the control means includes detection means for detecting the level of the ink in the storage container and generating an output signal when the level falls below the predetermined value; switch means for switching to a first switch state in response to said output signal from said pump motor means and switching to a second switch state in response to the absence of said output signal;
Pumping ink from the source to the reservoir in response to switching of the switch means to a first switch state and pumping ink from the source to the reservoir in response to switching to a second switch state. (6) No printing, ink supply status. (22) In (21), the switching means includes a comparator means and a flip-flop means, and the comparator means responds to the output signal from the detection means and the reference value signal to output the output signal. Compare with the reference value Shinyumi 1~,
A first comparator output is generated when the output signal from the previous Ha detection means is equal to or greater than the reference value, and a second comparator output is generated when the output signal is smaller than the previous Me reference value, and the flip-flop pump means switches to a first switch state in response to the first comparator output and switches to a second switch state in response to the second comparator output; □ and pumping ink from said source to said storage container when said flip-flop means is switched to a second switch state; An ink supply system that pumps into a storage container. (b)) In (21) or (22), further comprising indicating means for generating an indicating signal when the level of ink in the secondary storage container is equal to or greater than the predetermined value ('/), An ink supply system in which an indication signal indicates a full level of ink within said reservoir. h) in (2B), a clock means for applying a clock signal pulse to the indicating means and a clock signal pulse responsive to a switch state of the switch means, such that the level of ink in the storage container is below the predetermined value; a counter means that starts counting when the count value decreases, and the counter means generates the instruction signal when the count value reaches a maximum count value.