KR101038044B1 - Ink Supplying Device of Inkjet Printer - Google Patents

Abstract

The present invention provides an ink supply apparatus of an ink jet printer which realizes stable ink ejection by filling ink without mixing bubbles in the printer head.

The ink supply device is connected to the sub tank 120 and the sub tank 120 in which an ink storage chamber 123 in which ink is stored is connected through a printer head 60 and a connector portion 125 for discharging ink. It is configured with a main tank in which the ink supplied to the ink storage chamber 123 is stored. The sub tank 120 is formed with a first lead-out passage 127a and a second lead-out passage 126b connected from the ink reservoir 123 to the connector portion 125, and have a first lead-out passage 127a and a second lead-out. Openings on the ink storage chamber 123 side of the furnace 126b are formed at different height positions in the inward direction of the ink storage chamber 123.

Ink Supply Device, Ink Storage

Description

Ink Supply Device of Inkjet Printer

The present invention relates to an ink supply apparatus of an inkjet printer for supplying ink to a printer head for ejecting ink.

An ink jet printer discharges fine particles of ink from a nozzle while moving a print head having a plurality of nozzles relative to a print medium, and arrives at the print medium, such as letters, figures, shapes, photographs, and the like on the printing surface. It is a device for drawing. In inkjet printers, ink is consumed in accordance with the ejection of ink, so an ink tank (ink cartridge) having a capacity corresponding to the purpose is installed in the carriage of the print head or the printer body. In large inkjet printers that print commercial large commercials, paper, and the like, a large amount of ink is consumed in a relatively short time. For this reason, in such a commercial inkjet printer, a large-capacity ink tank is generally installed in the printer main body, and the ink tank and the print head are connected by a tube or the like, and are configured to be supplied from the ink tank to the print head in accordance with discharge of ink.

Here, when the internal pressure of the print head is higher than atmospheric pressure, the ink is extruded from the nozzle and falls on the print medium, causing a problem of so-called 'ink leakage'. Therefore, in the inkjet printer, the ink supply apparatus is configured so that the internal pressure of the print head is a micropressure which is slightly lower than atmospheric pressure. As a conventional ink supply apparatus, a small capacity subtank is provided between an ink tank (main tank) installed in a printer main body and a printhead installed in a carriage, and the printhead is brought into a non-pressure state by reducing the subtank. An ink supply device of a negative pressure generation method is known (see, for example, Japanese Patent Application Laid-Open No. 2004-284207 and Japanese Patent Application Laid-Open No. 2006-62330). In general, an inkjet printer, including the above-described ink supply device, has a possibility that ink or dust may adhere to the nozzles of the print head and the ink may not be discharged normally when the continuous use or the unused state continues for a long time. have. For this reason, there is a case in which a suction circuit for forcibly vacuum-absorbing ink remaining in the printer head is provided by capping the nozzle face of the printer head with a rubber cap during startup or the like (for example, Japanese Patent Application Laid-Open No. 2007-A). See 216535). By forcibly sucking in this manner, old ink is sucked and removed, new ink is sucked from the main tank and supplied into the printer head, and the ink can be recovered to a state where ink is normally discharged from the nozzle.

However, when capturing the ink by capping the nozzle face of the print head, for example, if the nozzle face and the rubber cap are displaced, there is a case where air enters from the gap between the nozzle face and the rubber cap and the suction force is lowered. Then, the old ink in the print head is sucked out and removed, but new ink sucked from the main tank becomes difficult to be supplied into the ink print head, and bubbles are easily mixed (not filled with ink) in the print head. Similarly, in the print head in which the ink supply device of the above-described method is configured, bubbles are likely to be mixed in the connection portion of the print head and the sub tank and in the print head. When ink is ejected from the nozzle in such a state, there is a problem that ejection defects are caused in which bubbles are ejected without ink being ejected from the nozzle, which makes it difficult to obtain stable ink ejection.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an ink supply apparatus of an inkjet printer which realizes stable ink ejection by filling ink without mixing bubbles in the printer head.

In order to achieve the above object, the ink supply apparatus of the inkjet printer according to the present invention includes a printer head for discharging ink with a printer head side supply path (for example, the connector portion 125 in the embodiment) interposed therebetween; An ink chamber (for example, the ink storage chamber 123 in the embodiment) to which the ink is stored is connected to the sub tank formed therein and the main tank in which the ink supplied to the ink chamber is stored. Have The sub tank is provided with a plurality of supply holes (for example, the first lead-out passage 127a and the second lead-out passage 126b in the embodiment) connected to the head-side supply passage from the ink chamber, The ink chamber side openings of the at least two supply holes of the plurality of supply holes are formed at different height positions in the inward direction of the ink chamber.

In addition, the inkjet printer includes a main body member (e.g., the apparatus body 1 in the embodiment) having a media support (e.g., the platen 20 in the embodiment) for supporting a print medium and the A carriage installed to be relatively movable with respect to the main body member so as to face the print medium supported by the media support unit, the main tank is installed on the main body member, and the print head and the sub tank are installed on the carriage Can be configured.

In the ink supply apparatus of the ink jet printer according to the present invention, a plurality of supply holes are formed in the sub tank from the ink chamber to the head side supply path, and the ink chamber side openings of at least two supply holes of the plurality of supply holes. Are formed at different height positions in the inward direction of the ink chamber. From such a configuration, for example, when the ink is filled in the head side supply path through which ink escapes during cleaning of the print head, and the ink is filled in the head side supply from the supply hole formed at the position where the ink chamber side opening is low among the plurality of supply holes, Ink can be sent to the print head through the furnace. At this time, as the ink is filled, bubbles existing in the head side supply path and in the printer head can be gradually sent to the head side supply path. And the bubble sent to the head side supply path can be discharged to an ink chamber through the supply hole formed in the position where the ink chamber side opening is high among a some supply hole. Therefore, the ink supply apparatus of the inkjet printer according to the present invention can fill ink without mixing bubbles in the head-side supply path and in the printer head, so that stable ink ejection after ink filling can be realized.

Further, of the ink supply apparatus according to the present invention described above, a configuration in which the main tank is provided in the body member of the inkjet printer is preferable. In this configuration, a relatively large main tank can be provided at any position of the main body member. For example, the main tank can be provided in a gap space of the main body member, thereby miniaturizing the entire inkjet printer. In addition, by installing the main tank in a position where the operator can easily reach, for example, it is possible to facilitate the replacement of the main tank.

EMBODIMENT OF THE INVENTION Hereinafter, the preferred embodiment of this invention is described, referring drawings. As an example of an inkjet printer to which the present invention is applied, ultraviolet rays which are cured by being irradiated with ultraviolet light are adopted by adopting a type in which one axis is a movement of a print medium and the other axis is a movement of a printer head among two orthogonal two axes along the printing target surface. The structural example applied to the UV curing inkjet printer (henceforth a printer apparatus) using curable ink (so-called UV ink) is demonstrated. Fig. 1 shows a perspective view of the printer device P of the present embodiment as viewed obliquely from the front, and Fig. 2 shows a perspective view of the printer device P as viewed obliquely from the back, and shows the main structure of the main assembly 1 of the printer device P. 3, first, the overall configuration of the printer apparatus P will be described with reference to these drawings. In the following description, the directions indicated by the arrows F, R, and U shown in FIG. 1 are described as forward, right, and upward, respectively.

The printer apparatus P is provided in front of and behind the apparatus main body 1 having a large divided drawing function, and the support part 2 supporting the apparatus main body 1, and outputs the unprinted printing medium M wound in a roll shape. The delivery mechanism 3, the winding mechanism 4 which winds up the printing medium M which finished drawing, etc. are comprised.

The apparatus body 1 has a horizontally elongated window-shaped media inserting portion 15 for inserting the print medium M back and forth in the upper and lower middle portions of the frame 10 forming the body. The media moving mechanism 30 for moving the platen 20 supporting the print medium M and the print medium M supported on the platen 20 back and forth in the lower frame 10L positioned below the 15. Is installed, the carriage 40 for holding the printer head 60 and the carriage moving mechanism 50 for moving the carriage 40 to the left and right in the upper frame 10U positioned above the media inserting portion 15 are provided. It is installed. The apparatus main body 1 includes the front and rear movement of the print medium M by the media moving mechanism 30, the left and right movement of the carriage 40 by the carriage moving mechanism 50, the ejection of ink by the print head 60, A control unit 80 for controlling the operation of each part of the printer device P, such as supply of ink by the ink supply device 100, which will be described later, is provided, and an operation panel 88 is provided on the front of the apparatus body 1. It is installed.

The platen 20 extends down the front and rear sides of the media inserting portion 15 and is installed in the lower frame 10L. The print medium M is horizontally positioned in the left and right band-shaped drawing regions of the print head 60. The media support part 21 which supports is formed. The media support portion 21 has a plurality of small diameter adsorption holes formed therein and is connected to a pressure reducing chamber (not shown) provided below the media support portion 21. The pressure reducing chamber is set to a negative pressure by the operation of the vacuum generator. At this time, the print medium M is held by the media support 21 so that the position of the print medium M does not shift during printing.

The media moving mechanism 30 has an upper circumferential surface exposed to the platen 20 and is provided with a roller having a cylindrical feed roller 31 extending from side to side and the feed roller 31 rotating through the timing belt 32. The roller assembly 35 which consists of the drive motor 33, etc., and has the pinch roller 36 which is free to rotate back and forth, respectively, is arrange | positioned at the upper side of the feed roller 31, and a plurality is installed. The roller assembly 35 is configured to be set at a clamp position for pushing the pinch roller 36 to the feed roller 31 and at an unclamp position spaced apart from the feed roller 31, and the roller assembly The print medium M is driven by rotationally driving the roller drive motor 33 while the print medium M is sandwiched between the pinch roller 36 and the feed roller 31 by setting 35 at the clamp position. It is conveyed back and forth with the feed amount according to the rotation angle (drive control value output from the control unit 80) of the feed roller 31. 3 shows both the state which set the roller assembly 35 in the clamp position, and the state which set it to the unclamp position.

The carriage 40 is supported by the guide rail 45 which extends in parallel with the feed roller 31 and installed in the upper frame 10U, and is freely moved from side to side through a slide block (not shown). Driven by the mechanism 50. The carriage 40 is provided with a printer head 60 for discharging the UV ink, and the nozzle face at the bottom of the head is disposed to face the media support 21 of the platen 20 with a predetermined gap.

In general, the print head 60 includes a plurality of print heads arranged side by side according to the quantity of ink used in the printer device P. For example, cyan (C), magenta (M), and yellow ( Y), in the case of the printer apparatus using one ink cartridge for each color with respect to the basic four-color UV ink of black (K), as shown in a perspective view of the carriage periphery in FIG. Four printer heads 60 (first printer head 60C, second printer head 60M, third printer head 60Y, and fourth printer head 60K) are provided. The carriage 40 includes a sub tank 120 (the first sub tank 120C, the second sub tank 120M, the third sub tank 120Y, and the fourth sub tank) of the ink supply apparatus 100 described in detail later. 120K) is provided corresponding to each of the printer heads 60C, 60M, 60Y, and 60K. 6 and 7, the filter assembly 61 which consists of the filter holding member 61a which holds the filter 61b and the filter 61b is provided in the upper surface of the printer head 60. As shown in FIG. The filter 61b filters the UV ink sent from the sub tank 120, and the UV ink filtered by the filter 61b is sent to the ink chamber of the printer head 60. On the other hand, the drive mode (discharge method of ink fine particles) of the printer head 60 may be either a thermal method or a piezo method.

UV light sources for irradiating and curing ultraviolet light to UV ink discharged from the print head 60 to the print medium M are provided on the left and right sides of the carriage 40. The UV light source is composed of a left UV light source 70L provided at the left side of the carriage 40 and a right UV light source 70R provided at the right side of the carriage 40, and these left and right UV light sources 70L, 70R are formed of a carriage ( The first to fourth printer heads 60C, 60M, 60Y, and 60K provided in 40 are interposed between the left and right sides. The left UV light source 70L and the right UV light source 70R are configured using a light source that emits ultraviolet light having a wavelength lambda of about 100 to 380 nm, for example, a UV lamp or a UV-LED. The flashing operation of the left and right UV light sources 70L and 70R is controlled by the control unit 80 in accordance with the movement of the carriage 40 by the carriage drive mechanism 50 and the ejection of ink from the printer head 60. .

The carriage moving mechanism 50 includes a drive pulley 51 and a driven pulley 52 provided in the left and right sides of the frame 10 with the guide rails 45 interposed therebetween, and a carriage for rotating the drive pulley 51. And a timing belt 55 in the form of an endless belt wound between the drive motor 53, the drive pulley 51 and the driven pulley 52. The carriage 40 is fixedly connected to the timing belt 55, and the carriage 40 supported by the guide rail is rotated by the carriage drive motor 53 by rotating the carriage driving motor 53 (control unit (control unit ( The upper side of the platen 20 is moved left and right by the amount of movement according to the drive control value output from 80).

The control unit 80 includes a RAM 82 and a RAM 82 which temporarily store a ROM 81 in which a control program for controlling the operation of each part of the printer device is written, a print program to be written on the print medium M, and the like. Arithmetic processing on a print program read from the control panel, an operation signal input from the operation panel 88, and the like, and an operation state of the arithmetic processing unit 83, which controls the operation of each part according to the control program, and the printer device P. A display panel for displaying a display panel and an operation panel 88 provided with various operation switches, and the like, and the front and rear movement of the print medium M by the media moving mechanism 30 and the carriage 40 by the carriage moving mechanism 50. Control of the ink, the ink supply by the ink supply apparatus 100, the ink ejection from each nozzle of the printer head 60, the ink supply by the ink supply apparatus 100, and the like are controlled.

For example, in the case of drawing on the print medium M based on the print program read by the control unit 80, the media moving mechanism 30 moves forward and backward M and the carriage movement of the print medium. By combining the left and right movement of the carriage 40 by the mechanism 50, the print medium M and the print head 60 are relatively moved, and ink is discharged from each print head 60 to the print medium M. Then, the UV light source (for example, the left UV light source 70L is turned on when the carriage is moved to the right) located behind the moving direction of the carriage 40, and the information according to the print program is drawn.

In this way, as the printer device P which is outlined, UV ink is supplied to the printer head 60 provided in the carriage 40 by the ink supply device 100. 4 is a schematic diagram of the ink supply device 100, FIG. 6 is an external perspective view of the sub tank 120, FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6, and FIG. 8 is a section VIII-VIII of FIG. 9 is a schematic block diagram of the ink supply apparatus 100.

The ink supply device 100 includes a sub tank 120 connected to the print head 60, a main tank 110 stored in a UV ink connected to the sub tank 120, and supplied to the sub tank 120. Sub-tank pressure reducing unit 140 for reducing the internal pressure of the tank 120 in a negative pressure state, sub-tank pressurizing unit 150 for pressing the internal pressure of the sub tank 120 in a positive pressure state, the main tank 110 It consists of an ink transfer unit 115 for transferring the UV ink stored in the sub-tank 120, the sub-tank pressure reducing unit 140 and the sub-tank pressurizing unit 150 by one gas transfer pump 160 It is composed.

The main tank 110 is set to store the UV ink of the capacity according to the ink consumption per unit time in this printer apparatus P. FIG. In the present embodiment, for the four colors C, M, Y, and K described above, each cartridge type main tank 110 (first main tank 110C, second main tank 110M) having a capacity of about 500 ml of each color; The structural example which detachably installed this main tank 110 on the back of the apparatus main body 1 using the 3rd main tank 110Y and the 4th main tank 110K is shown (refer FIG. 2). . By such a configuration, the large main tank 110 can be installed at any position of the apparatus main body 1 within the head of the liquid transfer pump 118 which will be described later, so that the printer P can be miniaturized. . In addition, by installing the main tank 110, for example, in a position that can be easily reached by the operator, it is possible to facilitate the main tank 110 replacement operation. On the other hand, the main tank 110 may be in the form of a cylindrical container shape or a flexible encapsulation shape, and the installation position of the ink tank may be separate from the front side or the top of the apparatus body 1 or the apparatus body 1. Can be installed as appropriate.

As shown in FIG. 6, the sub tank 120 opens a thin rectangular box-shaped box member 121 that is opened to one side (right) and is vertically long viewed from the side, and the opening face of the box member 121. The cover member 122 is covered and closed, and an ink storage chamber 123 is formed inside the tank formed by the closing of the cover member 122 to store the UV ink. In addition, it is connected with the ink storage chamber 123, and a float-shaped float receiving portion 124 extending vertically from the rear portion of the ink storage chamber 123 is formed. In the float receiving portion 124, a magnet 134a is fixedly installed at the center portion, and a disk-shaped float 134 floating in UV ink is freely accommodated. On the other hand, as the float 134, the structure which used what is specific gravity about 0.25, for example is preferable.

The sub tank 120 is integrally joined by applying a sealant or adhesive to the opening edge of the box member 121 to close the lid member 122, and to a fastening means such as a screw (not shown). By firmly coupled by the ink storage chamber 123 is held in a sealed state. At least one of the cover member 122 and the box member 121 is formed using a transparent or translucent material, and the storage state of the UV ink in the ink storage chamber 123 and the floating state of the float 134 in the UV ink. The back can be visually configured from the outside.

On the lower side of the sub tank 120, a short cylindrical connector portion 125 protruding downward from the bottom wall 121b of the box member 121 is formed, and the inside of the connector portion 125 faces downward. An open connector space 125a is formed. A block-shaped duct portion 126 extending upward from the bottom wall 121b in the ink storage chamber 123 is formed above the connector portion 125. Then, a first lead-out passage 127a is formed through the bottom wall 121b up and down to connect the bottom surface of the ink storage chamber 123 and the connector space 125a. The duct portion 126 and the bottom wall 121b are formed. The second lead-out path 126b which penetrates up and down and connects the upper surface 126a of the duct part 126 and the connector space 125a is formed. In addition, the connector portion 125 and the filter assembly 61 are connected using the tube 69, and a tube space 69a is formed inside the tube 69. Therefore, the ink reservoir chamber 123 of the sub tank 120 and the ink chamber of the printer head 60 have a first lead-out passage 127a, a second lead-out passage 126b, a connector space 125a, and a tube space 69a. Connected via Here, the cross-sectional area of the first lead-out passage 127a is formed smaller than the cross-sectional area of the second lead-out passage 126b. On the other hand, the bat | vat which receives UV ink below the print head 60 (60C, 60M, 60Y, 60K) in the state which positioned the carriage 40 at the non-printing reference position (so-called home position). The ink tray 180 of a shape is provided (refer FIG. 5).

On the back side of the sub tank 120, a sub tank storage detection unit 130 for detecting the storage state of the UV ink in the ink storage chamber 123 is provided. The sub tank storage detection unit 130 includes a float 134 which is freely accommodated in the floating container 124 extending vertically, and which floats along with the liquid level of the UV ink in the ink storage chamber 123, and the float 134. The magnetic sensor 136, which detects the liquid level of the UV ink by detecting the magnetism of the magnet 134a fixedly mounted on the s), is configured with the liquid level detection substrate 135 mounted thereon. On the other hand, a configuration using an anisotropic ferrite magnet as the magnet 134a is preferable, and a configuration using a bipolar detection sensor as the magnetic sensor 136 is preferable.

The rear wall 121r of the box member 121 is formed with a dovetail groove-shaped substrate mounting portion 131 extending up and down, and the liquid level detection substrate 135 is fixed to the substrate mounting portion 131. In this case, the plurality of magnetic sensors 136 mounted on the liquid level detection substrate 135 are positioned up and down. That is, the liquid level detection substrate 135 is disposed to face the float 124 with the rear wall 121r interposed therebetween, and the magnet 134a fixed to the float 134 in the float receiving portion 124. By detecting the magnetism by the magnetic sensor 136, the height position of the float 134, that is, the liquid level of the UV ink stored in the ink storage chamber 123 can be detected. 7, the float 134 and the float accommodating part 124 are formed so that the float 134 may move about straight according to the liquid level of UV ink.

In the present embodiment, the liquid level detection substrate 135 is mounted and fixed to the substrate mounting portion 131, and the plurality of magnetic sensors 136 mounted on the liquid level detection substrate 135 are arranged side by side, so that the liquid level detection substrate ( 135 shows an example in which the liquid level height position of the UV ink in the ink reservoir 123 can be detected in detail. With such a configuration, based on the detected liquid level position, for example, it is possible to control, for example, after grasping the temporal trend of the remaining amount of UV ink, to report to the operator the next processing that is expected to be necessary. On the other hand, as the magnetic sensor 136, the UV ink in the ink storage chamber 123 and the high detection sensor 136H which detects that the ink storage chamber 123 is filled with UV ink to detect that the liquid level of the UV ink is at the filling reference height. May be mounted on the liquid level detection substrate 135 by mounting two of the low detection sensors 136L for detecting that the power consumption is less than a predetermined amount. The output signal of the liquid level detection substrate 135 is input to the control unit 80.

On the front side of the sub tank 120, an ink introduction path penetrating back and forth through the front wall 121f of the box member 121 is formed at a predetermined height position between the upper and lower weights, and the tube connector 128 is connected to the ink introduction path. ) Is installed. In addition, the upper surface of the sub tank 120 is formed with a gas introduction path penetrating up and down the ceiling wall 121t of the box member 121, the tube connector 129 having a gas introduction hole 129a is formed in the center Is connected to this gas introduction path.

In addition, the backflow prevention part 132 is formed in the ink reservoir 123 below the tube connector 129. The backflow prevention part 132 mainly consists of the float support part 132a and the sealing float 133. The float support part 132a is a pair of front and back, The vertical part 132e extends downward from the lower surface of the ceiling wall 121t, respectively, The front end part is bent back and forth, and the engagement rib 132b is formed. Engaging ribs 132 and 132 are positioned with rib gap 132c in front and rear, and float support portion 132a has a left and right gap 132d between the lid member 122 as shown in FIG. And the sealing float 133 is accommodated in the sealing float accommodating part 132f extended up and down surrounded by the front-rear pair float support part 132a, and is free to move. In addition, when the sealing float 133 ascends to the upper limit position in the sealing float receiving portion 132f, the sealing float 133 can contact the lower end opening of the gas introducing hole 129a and close the gas introducing hole 129a. It is formed in size. On the other hand, the pressure control of the ink storage chamber 123 by the sub-tank pressure reducing section 140, which will be described later, is made by sucking the air in the ink storage chamber 123 mainly through the left and right gaps 132d and into the gas introduction hole 129a. . In addition, pressure control of the ink storage chamber 123 by the sub tank pressurizing unit 150, which will be described later, is performed by introducing air into the ink storage chamber 123 mainly through the left and right gaps 132d from the gas introduction hole 129a. . Moreover, the structure which used the thing with the specific gravity about 0.25 as the sealing float 133, for example is preferable.

The ink transfer unit 115 is formed by a main supply circuit 116 connecting between the main tank 110 and the sub tank 120. The main supply circuit 116 includes an ink suction line 117a connected to the main tank 110 and the liquid transfer pump 118, and an ink delivery line 117b connected to the liquid transfer pump 118 and the tube connector 128. ), A liquid transfer pump 118 or the like installed in the apparatus main body 1 and supplying the UV ink stored in the main tank 110 to the sub tank 120. The liquid transfer pump 118 is a pump capable of pumping the UV ink into the sub tank 120 even when the ink suction line 117a is not filled with the UV ink and the air is mixed. For example, a tube pump or a diaphragm may be used. Pumps are preferably used.

The sub tank decompression unit 140 is formed by a negative pressure circuit 141 connecting between the sub tank 120 and the suction port 161 of the gas transfer pump 160. The negative pressure circuit 141 is surrounded by the frame A in FIG. 4 and shows the main components of the air chamber 142 and the pressure sensor 144 for detecting the pressure of the negative pressure circuit 141. A line 147 formed by a negative pressure control valve 145 for opening / closing the negative pressure circuit 141 and a tube connecting these devices to connect the inlet 161 of the gas transfer pump to the sub tank 120 ( 147a, 147b, 147c, and 147d). On the other hand, the portion enclosed by the frame C in Figure 4 is installed in the carriage 40, the outside of the frame is a device that is installed in the device body (1).

The air chamber 142 is connected to the inlet 161 of the gas transfer pump 160, and the air in the chamber is exhausted by the operation of the gas transfer pump 160 to reduce the pressure to a negative pressure state. The air chamber 142 is provided with an air introduction line 147i for introducing air into the chamber decompressed under the negative pressure. The air introduction line 147i is provided with a flow regulating valve 143a for adjusting the flow rate of air and an air filter 143b for dust removal. The flow rate adjustment valve 143a is configured to adjust the flow rate of the air flowing into the air chamber 142 while the gas transfer pump 160 and the sub tank 120 are connected through the negative pressure circuit 141. The internal pressure of 142 is made static. As a result, a predetermined negative pressure of about -1 to -2 kPa (for example, negative pressure of -1.2 kPa, hereinafter referred to as 'setting negative pressure') in which the internal pressure of the ink storage chamber 123 is suitable for forming a meniscus in the nozzle portion It is set to).

The negative pressure control valve 145 is disposed between the air chamber 142 and the sub tank 120 and installed in the carriage 40, and the electrons for switching the line 147c and the line 147d into a connected state and a disconnected state. It is an electrostatic valve. In the present embodiment, a configuration using a three-way valve as the negative pressure control valve 145 is illustrated, and a line 147c and a normal open in a common port (COM) of the negative pressure control valve 145 are shown. A line 147d is connected to a port (Nomal Open Port NO), and a normal close port (NC) is open to the atmosphere through the line 147x and the silencer 148.

For this reason, when the negative pressure control valve 145 is off (normal operation such as during printing or in the air), the line 147c and the line 147d are connected and the negative pressure circuit 141 is set in the connected state. The suction port 161 and the sub tank 120 are connected via a joining circuit 171 described later. On the other hand, when the negative pressure control valve 145 is on (ink filling or cleaning, etc.), the connection between the line 147c and the line 147d is cut off, and the negative pressure circuit 141 is cut off and the line ( 147c is connected to line 147x, and the inlet side circuit of gas transfer pump 160 is open to the atmosphere. The negative pressure control valve 145 is connected to the control unit 80, and the on / off is controlled by the control unit 80.

The pressure sensor 144 has a detection area of about 5 kPa and is a gauge pressure type pressure sensor provided between the air chamber 142 and the negative pressure control valve 145 and detects the pressure in the line 147 near the sub tank. . The detection signal of the pressure sensor 144 is input to the control unit 80.

The sub tank pressurizing unit 150 is formed by a positive pressure circuit 151 connecting between the sub tank 120 and the discharge port 162 of the gas transfer pump 160. The constant pressure circuit 151 includes a flow control valve 153a for adjusting the flow rate of air, an air filter 153b for dust removal, as shown in a frame B of FIG. The pressure sensor 154 for detecting the pressure of the positive pressure circuit 151, the positive pressure control valve 155 for opening and closing the positive pressure circuit 151, and the outlets 162 and the subs of the gas transfer pump 160 by connecting these devices. And lines 157 (157a, 157b, 157c, and 157d) formed by a tube connecting the tanks 120 to each other. The flow rate regulating valve 153a adjusts the air flow rate flowing through the constant pressure circuit 151 while the gas transfer pump 160 and the sub tank 120 are connected by the positive pressure circuit 151, thereby preventing the internal pressure of the ink storage chamber 123. It is a valve which adjusts so that it may not rise above predetermined.

The positive pressure control valve 155 is disposed between the flow rate control valve 153a and the sub tank 120 and installed in the carriage 40, and switches the line 157c and the line 157d into a connected state and a blocked state. It is a solenoid valve. In this embodiment, a configuration using a three-way valve as the positive pressure control valve 155 is illustrated. The line 157c is connected to the common port COM of the constant pressure control valve 155 and the line 157d is connected to the normal close port NC. ) Is connected, and the normal open port NO is open to the atmosphere through the line 157x and the silencer 158.

For this reason, when the constant pressure control valve 155 is off (at normal operation, such as during printing or in the air), the connection between the line 157c and the line 157d is cut off and the positive pressure circuit 151 is cut off, 157c is connected to the line 157x, and the discharge port side positive pressure circuit of the gas transfer pump 160 is opened to the atmosphere. On the other hand, when the positive pressure control valve 155 is on (ink filling or cleaning, etc.), the line 157c and the line 157d are connected so that the positive pressure circuit 151 is set in the connected state, and the discharge port 162 and the sub The tank 120 is connected via the confluence circuit 171. The constant pressure control valve 155 is connected to the control unit 80, and the on / off is controlled by the control unit 80.

The pressure sensor 154 is a gauge pressure type pressure sensor installed in the carriage 40 with a detection area of about 50 kPa and detects the pressure of the line 157 near the sub tank. The detection signal of the pressure sensor 154 is input to the control unit 80.

The gas transfer pump 160 is a pump that sucks air from the negative pressure circuit 141 connected to the suction port 161, and pumps the sucked air to the positive pressure circuit 151 connected to the discharge port 162. ) And a suction pump 161 is used to generate a predetermined positive pressure or negative pressure. For example, a diaphragm pump generating a positive pressure or a negative pressure on the order of ± 40 kPa is preferably used.

The negative pressure circuit 141 and the positive pressure circuit 151 join on the way to the sub tank 120 to form a joining circuit 171. The joining circuit 171 is composed of a line 147d and a line 157d formed by joining and a line 177 connected to the sub tank, and a joining circuit open / close valve 175 for opening and closing the joining circuit 171. . The joining circuit on-off valve 175 is provided corresponding to the sub tank 120. In this embodiment, the joining circuit on-off valve 175 is branched into four joining circuits 171 (line 177). And each of the branched joining circuits (lines 177C, 177M, 177Y, 177K) and some symbols are omitted. The operation of the joining circuit shutoff valve 175 is controlled by the control unit 80.

In the ink supply apparatus 100 configured as described above, the operation of the liquid transfer pump 118, the negative pressure control valve 145, the positive pressure control valve 155, and the gas transfer pump 160 is controlled to the control unit 80. Is controlled as follows. On the other hand, as is clear from the description so far, the UV ink supply system is the same for the four systems (C, M, Y, K), so that the matters common to each system will be omitted by omitting these subscripts. do.

(Control at the time of normal driving)

When the main power supply of the printer device P is turned on, the control unit 80 reads the control program stored in the ROM 81 and controls the operation of each part of the printer device in accordance with the read control program. The ink supply device 100 is supplied with electric power to the gas transfer pump 160 to be in a rotational driving state, and all the joining circuit open / close valves 175 are turned on. At this time, the negative pressure control valve 145 and the constant pressure control valve 155 are both turned off. Accordingly, in the negative pressure circuit 141, the line 147c and the line 147d are connected to each other, and the suction port 161 and the ink storage chamber 123 are connected. In the positive pressure circuit 151, the line 157c and the line 157x are connected. Connected, the discharge port side circuit of the gas transfer pump 160 is opened to the atmosphere. For this reason, the air in the line 147 connected to the suction port 161 is sucked, the air chamber 142 is depressurized to a negative pressure, and the inflow air flow rate and the gas transfer pump 160 adjusted by the flow regulating valve 143a are carried out. It is stabilized at an approximately constant pressure determined by the balance of the amount of air sucked by. Here, the safety information is kept in a state where the internal pressures of the ink storage chambers 123 of the four sub tanks are all set to the same set negative pressure. In this way, when the printer apparatus P is started, the gas transfer pump 160 will continue to operate, and the internal pressure of the sub tank 120 will always be maintained at a set negative pressure irrespective of whether a printing program is running or waiting.

In normal operation, the UV ink is stored to some extent in the ink storage chamber 123 of the sub tank 120. The storage amount of the UV ink is controlled by any of the magnetic sensors 136 of the plurality of magnetic sensors 136 in which the magnets of the magnet 134a fixedly installed on the float 134 floating along with the liquid level of the UV ink are arranged up and down. It is a structure grasped | ascertained according to whether it detected. In this way, the magnetism of the magnet 134a is detected by the magnetic sensor 136, and the liquid level is detected. For example, the color of the UV ink can be compared with the method of detecting whether the light is transmitted through the inspection light. It is possible to detect the liquid level accurately without being influenced by the back.

The UV ink stored in the ink storage chamber 123 is discharged and consumed from the nozzle of the print head 60 by the execution of a print program or the like, and the stored UV ink is gradually reduced. When the UV ink stored in the ink storage chamber 123 becomes less than or equal to a predetermined amount, the UV ink stored in the main tank 110 is supplied to the sub tank 120 by the ink transfer unit 115 to replenish the UV ink.

Specifically, when the UV ink stored in the ink storage chamber 123 decreases, the liquid level of the UV ink decreases, and the float 134 also moves downward from the float receiving portion 124 according to the liquid level. And when the residual amount of UV ink becomes below a predetermined amount, the magnetism of the magnet 134a fixed to the float 134 is detected by the magnetic sensor 136 located in the up-and-down height below a predetermined amount. The control unit 80 receiving the detection signal from the liquid level detection substrate 135 starts the liquid transfer pump 118 with the ink reservoir 123 decompressed to a negative pressure state. The UV ink discharged from the main tank 110 by the liquid transfer pump 118 is supplied from the tube connector 128 to the ink storage chamber 123 via the line 117b, thereby increasing the storage ink amount of the ink storage chamber 123. do. At this time, the liquid level of the UV ink rises with the increase of the storage ink amount, and the float 134 also moves upward from the float containing portion 124 in accordance with the liquid level. Then, when the magnetism of the magnet 134a fixed to the float 134 is detected by the magnetic sensor 136 located at the filling reference height, the UV ink for the ink reservoir 123 is stopped by stopping the liquid transfer pump 118. Replenishment is complete.

By the way, suppose that the float 134 and the magnet 134a do not move with the float accommodating part 124 being located in the up-and-down height below a predetermined amount for some reason. As described above, since the control unit 80 operates the liquid transfer pump 118 until it detects that the UV ink has been supplied to the filling reference height, in this case, the UV ink continues after the filling reference height is exceeded. Supplied. At this time, the UV ink flowing into the sealing float containing portion 132f moves the sealing float 133 upward. The upper surface of the sealing float 133 is in contact with the lower end opening of the gas introduction hole 129a so that the sealing float 133 is the gas introduction hole 129a before the UV ink flows into the gas introduction hole 129a. ) Is to prevent. Accordingly, even if the liquid level of the UV ink is not normally detected by the magnet 134a, the UV ink can be prevented from flowing back into the gas introduction hole 129a.

(Control at the time of ink charge)

When no UV ink is present in the ink chamber of the print head 60, the sub tank 120, and the line 117 of the main supply circuit at the time of initial charging of the UV ink or at the start of the nozzle cleaning using the cleaning liquid. There is. In such a case, ink charge control is executed as follows in accordance with the ink charge command input from the operation panel 88 to the control unit 80. 10 shows a flowchart of the ink filling program PG set and stored in the ROM 81 with respect to this ink filling control.

In the operation panel 88, for example, when the ink filling process is selected by selecting a function key, the ink head execution command is input to the control unit 80 by specifying the print head 60. The calculation processing unit 83 maintains the internal pressure of the sub tank at negative pressure in step S10 according to the ink charging program (that is, both the negative pressure control valve 145 and the positive pressure control valve 155 are off), and the ink charging is performed. The joining circuit on / off valve corresponding to the printhead to be executed is turned on, and the process (negative pressure holding process) of turning off the other joining circuit on / off valve is performed, and the flow proceeds to step S20. For example, when ink filling is selected only for the first printer head 60C on the operation panel 88, only the first joining circuit opening / closing valve 175C corresponding to the first printer head 60 is turned on, The second to fourth joining circuit on-off valves 175M, 175Y, and 175K corresponding to the second to fourth printer heads are turned off (this case will be described below).

In step S20, UV ink is transferred from the first main tank 110C to the decompressed first sub tank 120C to replenish ink to the first sub tank 120C (ink replenishment processing). That is, only the liquid transfer pump 118C corresponding to the first sub tank 120C is started to supply the UV ink stored in the first main tank 110C to the first sub tank 120C. At this time, UV ink is slowly supplied from the tube connector 128. By doing so, the UV ink supplied to the first sub tank 120C flows along the outer peripheral wall surface of the connector space 125a and the tube space 69a through the first lead-out passage 127a having the opening formed at a lower position. It is lowered and sent to the filter 61b. At this time, bubbles existing in the connector space 125a, the tube space 69a, and the filter 61b are removed from the second lead-out passage 126b to the ink storage chamber 123, and at the same time, these areas are UV ink. Can be filled with As a result, the first lead-out passage 127a having the opening formed at the lower position is used for UV ink introduction, and the second lead-out passage 126b having the opening formed at the high position is used for the air discharge, thereby filtering the filter from the ink storage chamber 123. The UV ink can be filled with bubbles completely removed in the path to 61b. Then, after the inside of the path from the ink reservoir 123 to the filter 61b is filled with UV ink, the magnetism of the magnet 134a fixed to the float 134 may be detected by the magnetic sensor 136 located at the filling reference height. At that time, a sufficient amount of UV ink is stored in the ink storage chamber 123 of the first sub tank 120C by stopping the liquid transfer pump 118C.

Subsequently, in step S30, the negative pressure circuit 141 is cut off to pressurize the internal pressure of the first sub tank 120C to a constant pressure state by the sub tank pressurizing unit 150, and the UV stored in the first sub tank 120C. A part of the ink is discharged from the first printer head 60C (print head ink filling process). Specifically, the control unit 80 turns on the negative pressure control valve 145 to cut off the connection between the line 147c and the line 147d, and connects the line 147c to the line 147x to supply the gas transfer pump ( The suction side circuit of 160 is opened to the atmosphere. The positive pressure control valve 155 is turned on to connect the line 157c and the line 157d to connect the discharge port 162 of the gas transfer pump and the ink storage chamber 123 of the first sub tank 120C. By the switching control, the gas transfer pump 160 and the first sub tank 120C are connected through the constant pressure circuit 151, and the air discharged from the discharge port 162 of the gas transfer pump 160 is transferred to the first sub. It is supplied to the ink storage chamber 123 of the tank 120C. As a result, the UV ink stored in the ink reservoir 123 of the first sub tank 120C is pushed out of the first outlet passage 127a and the second outlet passage 126b at the bottom of the tank and filtered by the filter 61b. It is then supplied to the nozzle of the first printer head 120C. Then, the ink tray 180 receives the UV ink flowing out from the nozzle of the first printer head 120C.

By this step S30, the ink storage chamber 123 of the first sub tank 120C to the nozzle of the first printer head 60C is filled with the UV ink. At this time, bubbles existing in the path from the filter 61b to the nozzle of the first printer head 120C are pushed out of the nozzle, and the UV from the first sub tank 120C to the nozzle of the first printer head 60C is UV. The state is filled with ink, and the flow advances to the next step S40. On the other hand, at this time, the joining circuit on-off valve 175 is in a closed state except for the first joining circuit on-off valve 175C, and the internal pressures of the second to fourth sub-tanks are maintained at an initial set negative pressure.

In step S40, the positive pressure circuit 141 is blocked to reduce the internal pressure of the first sub tank 120C to a negative pressure state by the sub tank decompression unit 140, and the ink transfer unit (C) to the decompressed first sub tank 120C. The ink is transferred from the first main tank 110C by 115 to fill the first sub tank 120C with the UV ink (sub tank ink filling process). That is, the control unit 80 turns off the constant pressure control valve 155 to cut off the connection between the line 157c and the line 157d, and connects the line 157c to the line 157x, thereby providing a gas transfer pump 160. Open the discharge side circuit to the atmosphere. In addition, the negative pressure control valve 145 is also turned off, and the line 147c and the line 147d are connected to each other so that the ink storage chamber of the inlet 161 of the gas transfer pump 160 and the first sub tank 120C ( 123).

By the switching control, the gas transfer pump 160 and the first sub tank 120C are connected in the negative pressure circuit 141, and the air in the ink storage chamber 123 of the first sub tank is connected to the gas transfer pump 160. Aspirated. For this reason, the internal pressure of the 1st sub tank 120C falls, and it changes to a negative pressure state from a positive pressure state. The control unit 80 starts the liquid transfer pump 118C when the pressure detected by the pressure sensor 144 reaches a negative pressure of a predetermined value or less (for example, -0.8 kPa or less). Then, when the magnetism of the magnet 134a fixed to the float 134 is detected by the magnetic sensor 136 located at the filling reference height, the liquid transfer pump 118C is stopped. As a result, the UV ink is filled in the ink storage chamber 123 of the first sub tank 120C up to the filling reference height.

In the subsequent step S50, the pressure is reduced until the internal pressure of the first sub tank 120C detected by the pressure sensor 144 reaches the set negative pressure (for example, about -1.0 kPa). At this time, the valves are opened by turning on the second to fourth confluence circuit opening / closing valves 175M, 175Y, and 175K, which have been abolished so far, so that all of the first to fourth subtanks are held at a negative pressure of the set negative pressure. (Negative pressure holding process), the flow advances to step S60 to end the ink filling program PG. As a result, ink is filled in the first printer head 60C selected by the operation panel 88, and all the sub tanks including the first sub tank are set to a predetermined set negative pressure and held in the atmosphere. On the other hand, even when the ink filling process is performed for a plurality of print heads, the same operation is performed by turning on the confluence opening / closing valve on which the process is performed.

Here, the main effects of the ink supply apparatus 100 according to the present embodiment are summarized as follows. First, the first lead-out passage 127a and the second lead-out passage 126b having different height positions of the openings are provided below the sub tank 120. With this configuration, for example, when the UV ink is slowly supplied from the tube connector 128 at the time of initial charging of the UV ink or starting after cleaning the nozzle using the cleaning liquid, the first lead-out passage 127a having a lower opening is formed. To the connector space 125a. The UV ink sent to the connector space 125a flows down to the filter 61b along the outer circumferential wall surfaces of the connector space 125a and the tube space 69a. At this time, bubbles existing in the connector space 125a, the tube space 69a, and the filter 61b are sent to the ink storage chamber 123 from the second lead-out passage 126b without being removed, and the areas are removed by UV ink. You can fill with. In this state, by pressurizing the internal pressure of the sub tank 120 to a constant pressure state, the UV ink can be filled without mixing bubbles in the path from the sub tank 120 to the nozzle of the printer head 60. Therefore, it is possible to obtain stable ink discharge without discharge failure.

Secondly, by detecting the magnetism of the magnet 134a fixed to the float 134 formed so as to be able to move up and down substantially in the float receiving portion 124 with the magnetic sensor 136, the height position of the float 134, that is, ink The liquid level of the UV ink stored in the storage chamber 123 is configured to be detected. By such a configuration, the magnet 134a can be moved approximately straight along the liquid level of the UV ink while maintaining the direction in a constant direction. For this reason, the vertical height position of the magnet 134a moving in this way faithfully reflects the liquid level of the UV ink. Therefore, by detecting the magnetism of the magnet 134a by the magnetic sensor 136 and detecting the vertical height position of the magnet 134a, the liquid level of UV ink can be detected with good precision.

Third, in the ink reservoir 123 below the tube connector 129, the backflow prevention part 132 mainly comprising the float support part 132a and the sealing float 133 is formed. For example, even when the float 134 and the magnet 134a do not move while being located at an up and down height less than or equal to a predetermined amount by the float receiving portion 132, the filling reference height is higher than the filling reference height. UV ink supplied to the gas inlet flows into the gas introduction hole 129a and can be prevented from flowing back. Specifically, the UV ink supplied above the fill reference height and flowed into the sealing float container 132f moves the sealing float 133 upward in the sealing float container 132f. When the upper surface of the sealing float 133 contacts the lower end opening of the gas introduction hole 129a, the sealing float 133 is configured to cover and seal the lower end opening of the gas introduction hole 129a. Therefore, it is possible to prevent the UV ink from flowing back into the gas introduction hole 129a.

In addition, in the embodiment, as an example of the inkjet printer to which the present invention is applied, a configuration example applied to a UV curing inkjet printer of a uniaxial print media movement and a uniaxial printer head movement type has been described. For example, the present invention can be applied to an inkjet printer of a two-axis printer head moving type or an inkjet printer of a two-axis printing medium moving type, and the ink used may be applied to an inkjet printer using other types of inks such as dyes or pigments. Applicable

1 is an external perspective view of the printer device shown as an application example of the present invention as viewed obliquely from the front.

2 is an external perspective view of the printer device as viewed obliquely from the back.

Fig. 3 is a front view showing the main part structure of the apparatus main body in the printer apparatus.

4 is a system diagram of the ink supply apparatus.

5 is a perspective view of a carriage periphery in the printer device.

6 is an external perspective view of a sub tank installed in a carriage;

FIG. 7 is a cross-sectional view illustrating a portion VII-VII of FIG. 6.

FIG. 8 is a cross-sectional view illustrating a VIII-VIII portion of FIG. 6.

9 is a schematic block diagram of an ink supply apparatus.

10 is a flowchart of the ink filling program.

** Description of the sign **

M: print media

P: printer unit (inkjet printer)

1: Device body (body member)

20: platen (medium support)

40: carriage

60: printer head (60C: first printer head, 60M: second printer head, 60Y: third printer head, 60K: fourth printer head)

100: ink supply device

110: main tank (110C: first main tank, 110M: second main tank, 110Y: third main tank, 110K: fourth main tank)

120: sub tank (120C: first sub tank, 120M: second sub tank, 120Y: third sub tank, 120K: fourth sub tank)

123: ink reservoir (ink chamber)

125: connector part (head side supply path)

126b: second outlet furnace (supply hole)

127a: first lead-out furnace (supply hole)

Claims (3)

A main tank connected to a printer head for discharging ink with a print head-side supply path interposed therebetween, an ink chamber in which ink is stored, connected to the sub tank, and a main tank in which ink supplied to the ink chamber is stored In the ink supply apparatus of the inkjet printer having a, The sub tank is provided with a plurality of supply holes connected from the ink chamber to the head side supply path, The ink chamber side openings of the at least two supply holes of the plurality of supply holes are formed at different height positions in the ink chamber inner direction, When ink is supplied from the main tank to the ink chamber, the ink liquid level supplied from the main tank to the ink chamber is made lower than an opening formed at a higher position among the ink chamber side openings of the two supply holes, and the two supplies Ink is sent from the opening formed at the lower position of the ink chamber side opening of the hole to the printer head through the head side supply path, and bubbles existing in the head side supply path and in the printer head are at the high position of the supply path. The ink supply apparatus of the inkjet printer characterized by discharged from the formed opening to the ink chamber. The method of claim 1, The inkjet printer includes a main body member having a media support portion for supporting a print medium, and a carriage installed to be relatively movable with respect to the main body member, in opposition to the print medium supported by the media support portion. The main tank is installed on the body member, And the printer head and the sub tank are installed in the carriage. delete

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