JP5994043B2 - Inkjet recording device - Google Patents

Description

  Clarification of basic element conditions that can increase the capacity of ink that is a consumable to be mounted without increasing the size of the main body of the inkjet recording device used in homes and offices, and simple ink based on it The present invention relates to the configuration of the supply device.

  2. Description of the Related Art A widely used inkjet recording apparatus has a carriage on which a print head that reciprocates in a direction perpendicular to the paper traveling direction is mounted, and ink tanks of various colors are mounted on the carriage in a replaceable manner. In order to increase the amount of ink that can be used, another ink tank group is provided separately from the ink tank on the carriage, and the method of supplying ink from there to the ink tank on the carriage is also adopted depending on the purpose of use of the recording device. ing. In either method, stable ink supply to the print head is a basic problem, and various ideas have been accumulated for better solutions.

JP 07-068773 A JP 2001-138541 A JP 2010-228237 A JP 2009-226026 A JP 2011-245731 Japanese Patent No. 4359875 JP 2004-237731 A

  Consumer product genres (mainly for home use and SOHO use) and business use ink jet recording devices first appeared in the early 1990s, and then rapidly spread and formed a large market. Over the past 20 years, both text quality and photographic quality have improved dramatically, the specifications have been enriched, the design has been refined, and the price of the device itself has been drastically reduced. Above all, it has become an indispensable presence in the printing of photographs. Inkjet recording devices of the consumer product genre are on-carriage ink tanks, which are consumables that can be replaced when ink runs out. These are called ink cartridges. ing. The ink cartridge, which is a consumable item, has not changed the amount of ink that can actually be printed and the price, despite the enormous production volume for a long time.

  Users often hear opinions that “ink will run out soon” and “ink costs are high”. Also, even though I bought a high-performance printer, "I try to avoid using it as much as possible" or "I endure anyway by printing in a print mode that uses less ink even at the expense of image quality." Is also heard. In order to respond to this user's desire, third parties provide ink refill kits and ink refill products, but refills often get dirty, and refills are constantly subject to patent disputes with the original manufacturer. . On the other hand, from the original manufacturer, printers for business use have introduced large ink tanks to deal with, but consumer products printers for home use or SOHO have remained unclear. The development of appropriate technology is more difficult than a third party can imagine, and is it difficult for even a professional engineer to create a technology suitable for consumer products? User dissatisfaction has not yet been resolved.

  As a representative example, the ink cartridge used in the Japanese market is composed of four black and YMC color inks, and the actual sales price is about 5,000 yen (1 unit) Then about 1,000 yen). The number of sheets that can be printed in A4 size in the standard manuscript / standard printing mode (ISO / IEC2472 and 2471 compliant) is about 500. Therefore, the cost of printing ink for one sheet is about 10 yen. The catalog generally contains numbers of such a level. Since four colors of ink are used, the average number is 125 printable sheets per one color ink cartridge. Users have even said, “If this is the case, it would be better to buy a new printer when the ink runs out.” In fact, printers with a price of, for example, 5,800 yen appear at the store and are often bought. The dissatisfaction that “ink price is high” is also a problem in sales, so we will consider it, and we would like to respond to the dissatisfaction that “ink will soon disappear”. Since the solution should be a large-capacity ink cartridge, it is of course necessary that the ink cost per sheet can be reduced.

  A system in which each color ink tank is mounted on the carriage in a replaceable manner is called an on-carriage ink tank system. In addition to the ink tank fixed on the carriage, another type of replaceable ink tank, and a method of supplying ink from there to the ink tank on the carriage is called an off-carriage ink tank method.

  An on-carriage ink tank type printer is shown in FIGS. In a typical example of this method, an ink tank having a width of approximately 1.5 cm, a depth of 5 to 7 cm, and a height of 4 to 5 cm is mounted in a replaceable manner. A black ink whose main purpose is to print characters is usually about twice as wide as the above. The number of tanks may be a combination of four, black, yellow, magenta, cyan, and black for photography, seven, plus photo magenta and photocyan. The total width of the entire tank, including other color cartridge combinations, is approximately 8-12 cm. Here, in order to ensure the ease of replacement of the ink cartridge by the user, a solid carriage having a replacement mechanism is required, and the width for that purpose is also added. Since this is a reciprocating scan exceeding the paper width, the width of the apparatus main body is required to be at least the paper width plus 20 cm. In fact, the width of most consumer genre printers is well over 40cm. Therefore, it is difficult to increase the width of the ink tank any more in order to increase the amount of ink. The height and depth are close to the limit. In addition, increasing the on-carriage ink tank also increases the load on the motor that moves the carriage. The precision of carriage movement is a lifeline for printers.

  For these reasons, the ink capacity has not been increased for many years in the on-carriage ink tank system. In the case of the above-described wide black ink tank and the normal width of yellow, magenta, cyan, and a system of four colors, the total width is about 7 cm. In this case, a width in the width direction of 14 cm is required. Even in such a relatively narrow product group of ink cartridges, the increase in the amount of ink remains unchanged.

  The internal capacity of the ink tank in the above example is about 30 cc. If the height is 4 cm, the water head pressure is too high, and ink may leak from the print head. For this reason, sponge-like stuffing, a maze, and a valve are provided to prevent ink from dropping from the print head. One example can be found in cited document 1: Japanese Patent Application Laid-Open No. 07-068773. Although this technique is later improved and is considered to be used in actual products, the use efficiency of the ink cartridge volume drops to almost half due to this filling, and the effective ink amount is about 15 cc, for example. When using letters, recipes, and copying of net information, which are actually used, the ink consumption is about half that of the standard original printing, and the ink consumption per sheet is about 0.05 cc. Yes (It is a conversion value from the sum of the ink amount actually used for printing and the ink amount used for maintenance). Therefore, it can be said that printing of approximately 300 sheets / one ink cartridge is possible in calculation. This is consistent with the upper limit of the actual feeling of many users. (In this proposal, the explanation will be continued using 0.05 cc of ink consumption per sheet.)

  From the above, the problem is clear. It is a consumer product genre inkjet printer that is simple and does not increase the size of the main body, so it is waiting for the creation of a technical solution for an ink supply device that embodies the method of increasing the ink capacity that does not increase the cost. . In the on-carriage ink tank system, the amount of ink increase is limited as described above. The solution must be determined by the off-carriage ink tank method.

  There is also a problem with the width of the apparatus body. On a desk or office with a narrow home or SOHO, there is nothing special even if the height is, for example, 18 cm becomes 23 cm. However, if the width is 43 cm, for example, 48 cm, the occupied area is widened and it is quite difficult. It will be wider than laser printers of the same genre. It is a condition that the off-carriage ink tank for replenishing ink is not arranged in the width direction of the main body.

  FIG. 4 shows off-carriage ink tank placement location candidates that satisfy the above-described problems. Reference numeral 5 denotes an on-carriage ink tank in the off-carriage ink tank system, and 5 'indicated by a dotted line denotes an on-carriage ink tank in the on-carriage ink tank system. Reference numeral 6 denotes a place where the off-carriage ink tank can be placed, which is the top and bottom of the on-carriage ink tank, which are indicated as A, B, C, and D, respectively. Conventionally, the position of B, that is, the arrangement under the print head has been considered good. In this arrangement, the basic idea is to suck up ink from the ink tank by the negative pressure generated by the print head by ink ejection. It is said that since the ink tank is at the lower side, there is no fear of ink dropping from the print head due to the water head pressure of the tank, so that a simple mechanism can be used.

  However, there are actually some problems and various innovations have been made. As known examples, JP-A-2001-138541, JP-A-2010-228237, JP-A-2009-226026 and JP-A-2009-226026 can be referred to. In JP-A-2009-226026, a buffer chamber (called a sub-tank) is decompressed to a negative pressure state by a pump to stabilize printing, and if necessary, the buffer chamber is pressurized to a positive pressure state to store the stored ink. The printer head automatically sends it out. In any case, it is possible to suck up automatically using a negative pressure derived from the print head up to a depth of 2 to 3 cm, and a suction pump is required at a depth exceeding this. When a pump is used, a sensor, a switching valve, a control device, and the like are inevitably required, resulting in a costly configuration. However, these underlays are only one solution, and the present invention does not relate to them.

FIG. 4D, a candidate placement location for the off-carriage ink tank, this location is in the back of the body and tank replacement is not user friendly and therefore not adopted. User friendly places are places A and C. In both cases, an off-carriage ink tank is placed on the upper side of the print head, and the same logic can be considered as an ink supply mechanism. In this arrangement, the ink tank can be easily replaced from the front side of the apparatus. However, in the arrangement placed thereon, dripping from the print head of the ink by such head pressure to the print head is essential problem. Control of water head pressure is troublesome. However, if this can be solved, an ideal space can be obtained as an ink tank arrangement place. The aim of the present invention is to control water head pressure.

  In placing the off-carriage ink tank on top, a buffer chamber is basically provided at the same height as the print head, and the ink from the off-carriage ink tank is first guided here. Water pressure is applied to the buffer chamber, but it is cut off here so that it does not reach the print head. Citation 5: Japanese Patent Laid-Open No. 2011-245731 introduces a method of preventing ink drop by adjusting the pressure of the ink in the print head by adjusting the pressure of the upper space in the upper tank. A pressure control pump is used. At the time of cleaning the print head, the pressure of this tank is raised above the specified pressure by the control device, and the nozzle is intentionally dropped from the discharge port of the head. In any case, the pump, sensor and controller are essential components.

  In the case of placing on the off-carriage ink tank (arrangement of A and C) that is easy to increase in capacity, is user-friendly and does not require widening of the main body, (1) there is no ink spillage from the print head and ink ejection is obstructed An object of the present invention is to create an advanced ink supply system that has a stable ink supply performance, and (2) is realized with a simple and inexpensive configuration that makes it a consumer product.

In order to achieve the above object, the present invention provides, as a first problem solving means, in an ink jet recording apparatus, at least an on-carriage ink tank integrated with a print head and an upper limit (H + h) mm above the print head. (Hh) mm, a replaceable replenishment ink tank disposed within a height and a flexible ink conduit for guiding ink from the replenishment ink tank to the on-carriage ink tank. In the ink jet recording apparatus having a supply system, when the negative pressure fluctuation allowable range of the liquid chamber connected to the print head is − (P ± p) mmH 2 O, as a head pressure control mechanism for controlling the head pressure to the print head, When the opening / closing pressure is S, a valve for setting S = P + H is provided at the same height as the print head, and the height width 2 of the refilling ink tank mm to be within 2Pmm, ink supply from the refilling ink tank with these conditions to on-carriage ink container, it devised an ink jet system recording apparatus which comprises carrying out the head pressure and only this negative pressure Is.

As a further problem-solving means, in the problem-solving means 1, 2 and 3, an excessive positive pressure releasing mechanism for mixed bubbles is provided above the hydraulic head pressure control mechanism, and further, ink pulsation is generated in the on-carriage ink tank. A buffering mechanism for relaxing is provided.

  The operations and effects of the first problem solving means are as follows. First, in view of the object of the present invention, preferable conditions / judgment criteria for the installation location of the off-carriage ink tank are listed as follows. 1. There must be enough space for as many large capacity ink tanks as needed. Furthermore, although it is at the manufacturer's convenience, it is uneconomical in terms of design to change the location for each model. I want a space that can be placed in the same space with the required number according to the model. Also, if you want to increase the ink capacity further in the series development, instead of searching for another place, you just want to extend the depth and simply expand it. In short, I want you to have the freedom of spatial expansion. 2. Above all, it should be easy for users to exchange. 3. It is a simple water head pressure control mechanism that does not require the use of pumps or sensors, and the ink conduit must be easily opened. 4). These do not increase the height or width of the product.

  FIG. 1 is a cross-sectional view of a conventional model, and FIG. 2 is a plan view. Reference numeral 1 denotes a paper cassette, 2 denotes a paper discharge tray, and printing paper is conveyed from 1 to 2 through a paper path indicated by a dotted line 3 and discharged. In the middle of the printing process, ink droplets are ejected from the print head 4 according to information, and printing is performed. Reference numeral 5 denotes a replaceable on-carriage ink tank, and this method is mainstream in order not to enlarge the main body. FIG. 3 is a perspective view showing how the on-carriage ink tank in the conventional machine is replaced. Open the upper mechanism of the tank, and at the same time move the carriage to the center and then replace it.

  The arrangement of the replenishment off-carriage ink tank of the present plan is A or C in FIG. 4, and the ink supply mechanism can be handled uniformly as an upper placement system with respect to the print head. A typical configuration of the above-described placement system is shown in the cross section of FIG. 5 and the plan view of FIG. 1 is a paper cassette, 2 is a paper discharge tray, 3 is a paper path, 4 is a print head, 5 is an on-carriage ink tank, 6 is a refilling off-carriage ink tank, and 7 is a flexible ink conduit that connects the two. . FIG. 7 shows a perspective view. Here, a direction orthogonal to the printed material traveling direction, that is, a direction in which the on-carriage ink tank performs a reciprocating scanning motion, this is referred to as a product width. This is the width viewed from the user when the user is to use the product facing the printed product outlet side.

As can be seen, a huge space can be obtained across the width of the recording apparatus main body. As can be seen from FIG. 6 of the plan view, the off-carriage ink tank for replenishment with a large capacity, which is six colors in the example of this figure, is added as an example, but as shown by reference numeral 8, the expansion ink tank 3 Space can be taken. Even if these are loaded, the width of the product will be shorter than the conventional machine.
That is the point. This is because the on-carriage ink tank is no longer required to have as much ink as possible, and not only its height but also its width can be reduced. The numerical basis will be described later. The dotted line 10 in FIG. 6 and FIG. 7 above represents the conventional machine to be compared, and is large. It can be seen that the width of the recording device 9 of the present invention can be made narrower than this. Judgment criterion 1 is a method for obtaining a degree of freedom of expansion in terms of increasing the capacity, but sufficiently satisfies this criterion.

  Judgment criterion 2 is the ease of replacement by the user, but is a complete front operation as shown in FIG. It is only necessary to open the front door 9 and replace the ink tank for replenishment at the indicated (not shown) place. In FIG. 7, unlike FIG. 6, an example in which seven color ink tanks are arranged in the full width is shown.

  With regard to the criterion 3, both A and C are obtained from the arrangement space above the printed material conveyance path, and there is no difficulty in space, and one point of concern is whether water head pressure control is simple. If even this is simple, expensive things such as pumps, sensors and their control systems / circuits are unnecessary. This is described in detail in the following section. As already described, the criterion 4 can shorten both the width and the height, that is, the condition is sufficiently satisfied.

  However, it is well known to arrange the replenishment ink tank above the front of the printer. The gist of the present invention is the logic that realizes this arrangement with a simple mechanism. The ink supply to the ink tank on the carriage uses only the negative pressure derived from the print head and the water head pressure from the replenishment off-carriage ink tank, and does not use a pump or a sensor.

  The water head pressure fluctuation range ± h mmH2O brought to the print head by the ink in the replenishment ink tank is within the allowable negative pressure fluctuation range ± p mmH2O of the liquid chamber connected to the print head, that is, the height width of the replenishment ink tank The basic element of the present invention that 2 h mm is within 2 p mm will be logically studied. See FIG. 8 and FIG. One of the essential conditions is that “the ink head does not leak even when the water head pressure from the replenishing ink tank to the print head is maximum and the negative pressure applied to the print head is the weakest”. That is the point.

  The height of the refilling ink tank from the print head is (H ± h) mm. (H + h) mm is the hydraulic head pressure when the ink is full, and (H−h) mm is the hydraulic head pressure immediately before the ink reaches the bottom. Further, a negative pressure range that does not leak ink from the print head and does not increase so high that ejection becomes a problem is − (P ± p) mmH 2 O.

A head pressure control mechanism for controlling the head pressure caused by the ink in the replenishing ink tank is disposed at the same level as the print head. In a typical configuration, it is provided at the bottom of the on-carriage ink tank connected to the print head. One example of a mechanism is a valve. Assume that the opening pressure of this valve is SmmH2O. The above essential conditions can be expressed as follows.
S− (H + h) ≧ P−p (1)
Here, the left side is when the maximum hydraulic head pressure H + h (mmH2O) is applied to the valve, that is, when it becomes S- (H + h), and this represents the state in which the valve is most easily opened. Nonetheless, the valve has a force greater than Pp where the negative pressure is the weakest, so the valve is not trying to open. In order to simplify the explanation, the density of the ink is set to 1 which is the same as that of water. Actually, the density of ink, which is mostly water, is approximate, and there is no problem in handling in this way.

Another essential condition is “the valve must be opened when the maximum value P + p of negative pressure is applied to the valve even under the condition where the valve is most difficult to open”. That is, S− (H−h) ≦ P + p (2)
Here, the left side represents a state where the minimum hydraulic head pressure Hh is applied to the valve and the valve is most difficult to open. Nevertheless, when the force of P + p with the strongest negative pressure is applied downward, the valve opens, supplying ink and preventing further increase of the negative pressure.

From the above formulas (1) and (2), −p + h ≦ S− (P + H) ≦ p−h (3)
Is guided. From now on,
∴ 2h ≦ 2p (4)
Is guided. That is, the height width (note: not the height position) 2h of the replenishment ink tank must be 2p or less of the allowable fluctuation range of the negative pressure.

The explanation of the operation of the second problem solving means is as follows. First, the maximum value of h is p. For example, if the negative pressure is −25 mm ± 10 mm H 2 O, this suggests that the height 2h of the replenishing ink tank is 20 mm corresponding to 2p. If the ink tank has a height width exceeding this, equation (3) will not hold. As a result, stable ejection is impossible and ink leakage occurs. It is one of the essential requirements of the problem solving means 2 that the height width 2h of the ink tank is within 2p.

  At this time, S = P + H or H = SP can be derived from the equation (3). In order to enlarge the ink tank for replenishment, the tank height width is set to the same number as 2p, which is the maximum allowable negative pressure fluctuation range, and the valve opening pressure S is set to H + P.

  This will be specifically described with reference to FIGS. The off-carriage ink tank 6 includes a connecting seal member 63. The connecting mechanism 71 of the printer body is provided with a needle 72. When the off-carriage ink tank 6 is attached to the printer body, the ink tends to flow from the needle 72 into the ink chamber 50 of the on-carriage ink tank 5 through the flexible ink conduit 7. A water head pressure control mechanism 51 is provided in the ink chamber. When the ink is purged from the print head by the initial setting control program when the off-carriage ink tank is replaced, the negative pressure in the liquid chamber 56 connected to the print head increases and reaches the design opening pressure S, the water head pressure control mechanism 51 is configured. The central element valve body 55 is pulled downward against the coil spring 53 to open as shown in FIG. 9, and ink flows from the ink chamber 50 into the liquid chamber 56 connected to the print head. As a result, the negative pressure in the liquid chamber 56 decreases. When the design closing pressure is reached, the valve body 55 is pulled back by the coil spring 53 and the ink flow is stopped. Thereafter, the ink discharge, negative pressure increase, valve opening, valve closing, negative pressure optimization, ink discharge, and the like are repeated by the printing operation. Here, 52 is a valve box and 54 is a valve seat packing, both of which are components of the hydraulic head pressure control mechanism 51.

  Ink delivery from the off-carriage ink tank is performed only by the hydraulic head pressure and the negative pressure, and this is controlled by the hydraulic head pressure control mechanism 51, which is a simple valve mechanism. No sensor or pump is required.

  In order to smoothly deliver ink from the off-carriage ink tank, a negative pressure accompanying the delivery should not be generated here. For example, in order to facilitate handling, a hard ink container 60 is used, and an ink bag 61 that is soft and naturally deflates as the ink is delivered is used. Although it is very general, it is important to open the hole 62 for taking in air in the hard ink container 60 in order to prevent the generation of negative pressure.

Although FIG. 9 is an explanation of the case of h = p of the second solving means, the range of negative pressure allowed the liquid chamber communicating with the print head - When (P ± p) mmH2O, replenishing the ink tank ( If the height position of the center of the (off-carriage ink tank) 60 is Hmm, the height width of the tank need only be 2 mm at maximum. The opening / closing threshold value S of the valve body 55 is obtained by setting the coil spring force so as to be (P + H) mmH2O.

  The above is the basic principle of the problem-solving means of the present invention and the explanation of the operation. The effects of this are as follows. 1. The replenishment ink tank is arranged above the print head, so that a wide arrangement space and expansion flexibility can be ensured, and a simple structure can be achieved by merely satisfying the above condition: h ≦ p. It was.

  In other words, a buffer chamber and a pumping pump that are required in other arrangements and methods that have been proposed so far are not necessary for supplying ink. Mechanical elements such as ink transfer means, sensors, switching valves, and flanges and control circuits related to these are also unnecessary. The ink simply flows down according to the water head pressure and negative pressure and flows into the on-carriage ink tank. It is simple, so it can reliably achieve the required functions at low cost.

  2. The height for placing the refill ink tank is arbitrary. It is only necessary to use a valve of S = (P + H) mmH2O (when p = h).

3. An object of the present invention is also not to increase the size of the recording apparatus. As mentioned above, the height of a typical on-carriage ink tank that has been used unchanged for 20 years is a trade-off that you want to load as much ink as possible, but you must avoid dropping ink. Due to its nature, it continues to be approximately 40 mm to 50 mm in height. And there is some simple organs to control the water head pressure. According to the present invention, the on-carriage ink tank integrated with the print head is not intended to store ink here, so it can be smaller. The height is 10 mm to 20 mm, although it depends on the type of valve mechanism or similar head pressure control mechanism to be included. Even if it is 20 mm, a space of 20 mm to 30 mm is vacated in the sky as compared with the conventional machine. A replenishment ink tank may be loaded here. In the above example, the maximum height width is 20 mm. It can be fully inserted into a 30 mm space. The above is a detailed description of what has been described above with reference to FIGS.

  4). The width of the recording apparatus can be reduced. Although it is a repetition of the description in the section on operation, it was described in the previous section that “the on-carriage ink tank is small because it is not intended to store ink here”, but this is not only the height. The width can be reduced. For example, within a few mm, and within 1 cm anyway. This number is merely an example, but it should be understood that the greater the number of ink colors, the greater the effect because the effect on the recording apparatus main body width is doubled.

5. The operation and effect of the problem solving means 3 will be described. As described above, the ink tank for replenishment can be arranged in the space 12 surrounded by the one-dot chain line in FIGS. 5 and 6 on the premise that the conditions of the problem solving means 1 and 2 are satisfied. This space is an upper position on the front side facing the user of the main body, and refilling ink tanks can be arranged in a line in a horizontal line there. It is very easy for the user to exchange. In the conventional machine shown in the perspective view of FIG. 3, the upper lid is opened, and in the case of a multifunction machine, the upper scanner is lifted together, but the ink tank is exchanged so as to look into it. On the other hand, in the arrangement of the present invention shown in FIG. 7, the front cover is opened and the necessary ink tank is replaced. The ease of handling of both is obvious. In FIG. 7, the size of the conventional machine is indicated by a dotted line 10. There are other constraints on the size of the product, and it is a design matter, but it is a great utility to ensure the degree of freedom that can be reduced.

  The size of the ink tank for replenishment is illustrated using numbers. For example, if the height is 22 mm (inner side 20 mm), the lateral width is 40 mm (inner side 38 mm), and the depth is 80 mm (inner side 70 mm), the internal capacity is 53.2 cc. As described above, assuming that the ink consumption of one printed sheet is 0.05 cc, the number of printed sheets is 1,064. The number of printable sheets is nearly three times that of conventional machines. Here, calculation is made with an example of black for text, black for photography, yellow, magenta, cyan, photomagenta, and photocyan for convenience. The black for characters is made large, for example, the width is 60 mm. The total lateral width is 60 + 40 × 6 = 300 mm. This approximates and does not exceed the paper width + on-carriage ink tank width x2. A product that is at least 5 cm narrower than a conventional machine with the same seven colors can be made.

  If you want to increase the ink capacity on a business-use machine, you can increase the depth and width of the ink tank. A specific configuration will be described later in Examples. To further increase the number of ink colors, the lateral width may be slightly narrowed to increase the depth. In this way, the degree of freedom in design becomes extremely high. However, it is essential that the inner height of the ink tank is 20 mm, and it is only necessary to keep this. (When negative pressure fluctuation tolerance is 20mm)

The actions and effects of other problem solving means will be described. An excessive positive pressure releasing mechanism for mixed bubbles is provided at the upper part of the water head pressure control mechanism. This is indicated by 59 in FIGS. If air bubbles are mixed in the ink chamber 50 for some reason (melted gas, mixed gas at the time of ink tank replacement, etc.), it expands when the liquid temperature rises, etc., and unintentionally pushes down the valve against the spring force, and the ink Will be pushed into the liquid chamber. As a result, the negative pressure in the liquid chamber is reduced, and ink drops from the print head 4 are caused. Bubbles are exemplarily shown in FIG. 8 and FIG. In order to prevent such an inconvenience, “gas release or excessive positive pressure release” is necessary. In an ink jet printer, the mechanism is basically incorporated in all on-carriage ink tanks. Also in the configuration of the present plan, it is a necessary mechanism in combination with the basic structure of the water head pressure control described above, and by this incorporation, it is possible to prevent inadvertent dropping of the print head.

Furthermore, the on-carriage ink tank repeatedly reciprocates violently by the printing operation, and the ink inside thereof is always in a disturbed state. If the individual ink state is directly transmitted to the print head, stable ejection cannot be performed. Therefore, a buffering mechanism for relaxing the turbulent movement of the ink is provided so as to protect the print head as indicated by numeral 57 in FIGS. This uses a continuous porous material, such as a sponge or fiber stuffing.

Cross-sectional schematic diagram of a typical conventional machine The plan view FIG. Schematic diagram of ink tank replacement Candidate space for replacement off-carriage ink tank Schematic diagram of typical configuration of this plan (cross section) The plan view FIG. Schematic diagram of ink tank arrangement example and replacement Refill ink tank and on-carriage ink tank 1 Refill ink tank and on-carriage ink tank 2 Gas release mechanism 1 Gas release mechanism 2 Other hydraulic head pressure control mechanism 1 Other hydraulic head pressure control mechanism 2 Still another head pressure control mechanism 1 Still another head pressure control mechanism 2 Other gas release mechanisms 1 Other gas release mechanisms 2 Schematic diagram (perspective view) of business use machine

  The basic configuration of the recording apparatus shown in FIGS. 5 and 6 and the hydraulic head pressure control mechanism 51 shown in FIGS. 8 and 9 used in the description so far are typical forms of the present invention. A specific configuration is shown by a consumer product genre photo printer using six colors of black, yellow, magenta, cyan, orange, and green. The inner dimension of each color of the on-carriage ink tank was 0.9 cm. Their partition walls are 0.1 cm (these ink tanks are not to be removed and replaced, so thickness and gaps are not necessary), the outermost wall is 0.2 cm, and the total width is 0.9 × 6 + 0.1 × 5 + 0.2 × 2. = 6.3 cm. This was mounted on a carriage having a width of 7 cm. Since the width of the main body is 21 cm, the width of the main body is 39 cm by adding 7 × 2 cm + α (approximately 4 cm due to mechanical parts such as gears and the thickness and gap of the exterior). The carriage width of the conventional on-carriage ink tank mounted is about 10 cm or more, and therefore the main body width is well over 40 cm.

  The depth is 5.0 cm in internal dimensions and is not shortened. This is because there is a sufficient margin in the depth direction of this place. The height was set to an outer dimension of 2.0 cm and an inner dimension of 1.6 cm. In the simple calculation, the capacity is about 7 cc. However, since the ink disturbance buffer member and the valve mechanism are provided, the free ink liquid amount (liquid amount excluding the liquid amount contained in the buffer member) is about 3 cc. This is the amount of liquid capable of printing about 100 sheets by continuous printing. Here, 0.03 cc is used for printing one standard original. Actually, it performs conversion calculation with 0.05 cc because it performs empty discharge or suction cleaning for the purpose of cleaning the print head, but it means that it is an amount that can be printed, if there is continuous printing, this amount is enough. . Since the valve opening delay is small, there is no problem even with such a small amount.

  The liquid chamber connected to the print head must be kept at a negative pressure. The allowable width − (P ± p) mmH 2 O is determined by factors such as the hole diameter and shape of the print head and the viscosity of the ink used. In a typical example, P is a level of 25 mmH2O and p is 10 mmH2O. -(P ± p) mmH2O is generally in the range of-(20 ± 10) mmH2O to-(30 ± 15) mmH2O. In the example of FIG. 5, the center of the off-carriage ink tank in the height direction is provided 5 cm from the print head. Here, since p = 10 mmH 2 O, the height width (2h) of the off-carriage ink tank was set to 2 cm (= 2p). The characteristics of the coil spring were designed so that the opening pressure S of the valve body was H + P, that is, 75 mmH2O.

  The size of the off-carriage ink tank can be designed with a high degree of freedom as long as the height width is strictly observed. What is exemplified in the section of action and effect is a part of a typical tank. As shown again, the height x width x depth is 20 mm x 38 mm x 70 mm in terms of inner diameter, and the printing dose is about 1,000 sheets. If the depth direction with more margins is doubled to 140 mm, 2,000 sheets can be printed. For business use printers, four colors are often sufficient. In such a case, the lateral width is further doubled, and 4,000 sheets can be printed.

  A tank capable of printing 10,000 sheets can be easily designed. In either case, the tank can be designed freely as long as the height is 2 cm (with an inner diameter). Since the height of the on-carriage ink tank can be lowered, the space left there becomes a suitable place for the replacement ink tank. Moreover, it can be used to the full width of the device. There is enough space in the depth direction. Regardless of whether you prefer the height of the tank, it is low anyway. This in turn brings about such design freedom or extensibility.

  An enlarged view of an embodiment of the gas release mechanism 59 is shown in FIGS. A simple and reliable method is to use a one-way valve and an air communication hole of a combination of the two, in which a film having a characteristic of not allowing liquid to pass but allowing gas to pass is stretched. For example, a gas release mechanism 59 is provided in the upper part of the ink chamber 5, and an upper open hole 59-1 and a lower open hole 59-2 are provided in this, and porous tetrafluoride is formed on the ink side of the lower open hole 59-2. Ethylene: A thin film 59-3 having a trade name of POFLON may be stretched and sealed. A one-way valve 59-4 that opens only in the upper direction is provided above the lower opening hole 59-2. When the pressure of the mixed gas in the ink chamber 50 rises above the atmospheric pressure in the upper opening hole, the one-way valve 59-4 is opened as shown in FIG. 11, and the mixed gas is released into the upper atmosphere. Otherwise, even if the ink chamber 50 becomes negative pressure, the one-way valve 59-4 is closed as shown in FIG. 10, and air is not sucked from the outside.

  Another embodiment of the hydraulic head pressure control mechanism 51 is shown in FIGS. 52-2 is a valve box, 55-1 is a valve body made of a thin spring plate, and closes the inlet 52-3. The valve body has an opening pressure set to SmmH2O. When the negative pressure of 56 increases due to the ink discharge and exceeds S in combination with the water head pressure, the valve body opens as shown in 55-1 of FIG. 13 and allows ink to pass through the inflow port 52-3.

  Still another hydraulic head pressure control mechanism 51 is shown in FIGS. 52-2 is a valve box, 55-2 is a spherical ball, and 55-3 is a coil spring. The ball and spring constitute a valve body. As the negative pressure increases, the valve body opens as shown in 55-2 of FIG.

  The enlarged view of other embodiment of the gas discharge | release mechanism 59 is shown in FIG. 16, FIG. 59-5 is a spherical ball and 59-6 is a coil spring. The ball and spring constitute a valve body. When the pressure of the mixed gas in the ink chamber 50 rises from the atmospheric pressure outside the upper opening hole, the spring 59-61 is pressed and contracted like the ball 59-51 in FIG. Open the gas outlet. Then, the mixed gas is released into the upper atmosphere.

  FIG. 18 shows a configuration example of a business use printer. Depending on the product specifications, the ink capacity may exceed 10,000, for example. This is easily possible as shown in this figure. For example, if the black extra-large-capacity off-carriage ink tank indicated by reference numeral 6-3 is an ink tank having a width of 20 cm, a depth of 20 cm, and a height of 2 cm, it is 800 cc and can print 16,000 sheets. Since the ink tank is thin, it can be arranged in two stages. The ultra-large capacity off-carriage ink tank for each color of YMC indicated by No. 6-4 is 400 cc if an ink tank having a width of 10 cm, a depth of 20 cm, and a height of 2 cm is capable of printing 8,000 sheets of each color. .

  The present invention is not limited to the above-described embodiments, and various elemental technologies proposed for known ink jet recording apparatuses can be incorporated according to the purpose of design, and can be supported by various embodiments. is there. Assuming that the height width 2h mm of the replenishment ink tank is within 2p mm of the negative pressure fluctuation allowable width and that the opening / closing pressure S of the head pressure control is H + P (when h = p).

  The present invention has been mainly described with an inkjet recording apparatus as a consumer product, and has also been introduced to business use printers. It can also be applied to large format printers, professional photographic printers, or industrial printers that may be costly. And even portable printers can have a significant effect if you use them, depending on your design goals.

4 Print head
5 On-carriage ink tank 6 Replenishment off-carriage ink tank 6-3 Black extra-large capacity off-carriage ink tank example 6-4 Color extra-large capacity off-carriage ink tank example 7 Ink conduit
8 Supplementary space for expansion of off-carriage ink tank for replenishment 10 Conceptual diagram of external shape of conventional machine 11 Outline conceptual diagram of recording apparatus of present invention 50 Ink chamber 51 Water head pressure control mechanism 52 Valve box 53 Coil spring 55 Valve body 55-1 Spring plate valve body 55-2 Ball valve body 55-3 Coil spring 56 Liquid chamber 57 connected to the print head Buffer mechanism 59 Gas discharge mechanism 59-3 Porous tetrafluoroethylene thin film 59-4 One-way valve 59-5 Ball valve body 59- 6 Coil spring 63 Connecting seal member 72 Needle

Claims (1)

At least an on-carriage ink tank integrated with the print head, and a replaceable replenishment ink tank disposed within a height having an upper limit (H + h) mm and a lower limit (H−h) mm above the print head And an ink jet recording apparatus having an ink supply system comprising a flexible ink conduit for guiding ink from the replenishing ink tank to the on-carriage ink tank, the negative pressure fluctuation allowable range of the liquid chamber connected to the print head is − ( When P ± p) mmH2O, as a head pressure control mechanism that controls the head pressure to the print head, a valve that sets S = P + H when the opening / closing pressure is S is provided at the same height as the print head. The height width 2hmm of the ink tank is set to 2 pmm or less, and the refilling ink tank is changed to the on-carriage ink tank under these conditions. Ink supply of ink jet type recording apparatus which comprises carrying out only the water head pressure and negative pressure.

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