JP4488085B2 - Ink jet recording apparatus and adjustment method thereof - Google Patents

Description

  The present invention relates to an ink jet recording apparatus in which a sub tank for supplying ink to a recording head is mounted on a carriage, and an adjustment method thereof, and more particularly, to an ink jet recording apparatus including a plurality of head units each having a recording head and a sub tank and the same. It relates to the adjustment method.

  An ink jet printer, which is one of ink jet recording apparatuses, is used for many printing including color printing in recent years because noise during printing is relatively low and small dots can be formed with high density. . For example, an ink jet printer of a serial printing type is generally mounted on a carriage and moves in the width direction of the recording paper, and moves the recording paper in a direction perpendicular to the moving direction of the recording head. Paper feeding means is provided, and printing is performed by ejecting ink droplets from the recording head to the recording paper based on the print data.

  An inkjet printer provided for office use or business use needs to be capable of handling a relatively large amount of printing. For this reason, a large-capacity main tank for each color is arranged on the printer main body side and connected to each main tank via an ink supply tube and each color connected via a recording head and an ink supply tube. There has been proposed a type in which each sub tank is arranged on a carriage, ink is replenished from each main tank to each sub tank, and ink is further supplied from each sub tank to the recording head (for example, Japanese Patent Laid-Open No. Hei 11). -161880, JP-A-11-240664, JP-A-11-240914, JP-A-6-121134).

  Nowadays, there is an increasing demand for large-sized ink jet printers capable of printing on large paper. In such an ink jet printer, the number of nozzles is increased in the recording head in order to improve the throughput. However, it is difficult to form a large number of nozzles with uniform characteristics in one recording head, and there is a limit to improving printing accuracy.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a large-sized ink jet recording apparatus with high recording efficiency and recording accuracy and an adjustment method thereof.

  To achieve the above object, in an ink jet recording apparatus according to claim 1 of the present invention, a recording head mounted on a carriage and reciprocated in the width direction of a recording medium to eject ink droplets to the recording medium; A plurality of head units which are mounted on the carriage together with the recording head so as to be position-adjustable, receive ink replenishment from a main tank and supply the ink to the recording head, are provided. . As a result, a large number of independent head units are arranged on the carriage. Therefore, a head unit having a certain degree of characteristics is selected and mounted, or a head unit having a predetermined characteristic is a head having a predetermined characteristic. Can be exchanged for a unit. Therefore, it is possible to improve the throughput for a large-sized recording medium, and to increase and maintain the recording accuracy. Furthermore, since the water head difference between the ink surface in the sub-tank and the nozzle formation surface of the recording head can be adjusted, fine adjustment for each recording head can be performed, for example, when considering common drive waveforms in an ink jet recording apparatus. Even without this, the amount of ink ejected from the nozzles can be made uniform, and the recording accuracy can be further improved.

  According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the position of the sub tank is adjusted during recording on the recording medium by the recording head. This makes it possible to adjust the water head difference between the ink surface in the sub-tank and the nozzle formation surface of the recording head, particularly during recording processing at the upper and lower ends of the recording medium, so that the amount of ink discharged from the nozzles can be made uniform. Recording accuracy can be further increased.

  According to a third aspect of the present invention, in the ink jet recording apparatus according to the first or second aspect, the position of the sub tank is finely adjusted at the stage of assembly with the carriage. As a result, the amount of ink ejected from the nozzles can be made uniform to some extent in the initial stage, so that the adjustment range of the position of the subsequent sub tank can be widened, and the dynamic pressure adjustment by the position of the sub tank during printing can be performed over a wide range. It can be performed stably.

  According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the fourth aspect, the fine adjustment of the position of the sub tank is performed according to the drive waveform appropriate voltage displayed for each of the recording heads. . As a result, the recording head having the highest drive waveform appropriate voltage, that is, the recording head that does not discharge ink with the same voltage as a reference, the ink surface in the sub-tank of the other recording head so that the appropriate ink amount can be discharged. The head difference can be adjusted by lowering the nozzle formation surface. A recording head with a low appropriate voltage has a larger change in dynamic pressure when the subtank height is changed, and therefore, it is sufficient to adjust a small number of subtanks. Further, since the adjustment is performed by lowering the sub tank, the ink does not drip from the nozzles by the adjustment. The same applies to adjustment during printing because the subtank is lowered.

  According to a fifth aspect of the present invention, in the ink jet recording apparatus according to the fourth aspect of the present invention, storage means for storing the driving waveform appropriate voltage for each recording head, and the driving waveform appropriateness for each recording head from the storage means. It is characterized by comprising an adjusting means for reading the voltage and finely adjusting the position of the sub-tank. Thus, the water head difference between the ink surface in the sub tank and the nozzle formation surface of the recording head can be automatically adjusted, so that an optimum print output can be obtained even if the print duty is changed.

  According to a sixth aspect of the present invention, in the ink jet recording apparatus according to the fifth aspect, the adjustment unit includes a table that stores an adjustment value of the position of the sub tank corresponding to the drive waveform appropriate voltage for each of the recording heads. Is characterized in that fine adjustment is performed based on the adjustment value of the position of the sub tank selected from the table in accordance with the drive waveform appropriate voltage for each of the recording heads read from the storage means. As a result, the number of nozzles used in the recording process particularly at the upper and lower ends of the recording medium is reduced compared to the normal time, so that the ink discharge weight per nozzle increases due to the fluctuation of the dynamic pressure in the flow path. There are problems such as darker colors than normal recording. Since the position of the sub tank can be quickly adjusted to the optimum position with reference to the table in which the adjustment value is written according to the nozzle, the recording accuracy of the upper and lower ends can be improved.

  According to a seventh aspect of the present invention, in the ink jet recording apparatus according to any one of the fourth to sixth aspects, the fine adjustment of the position of the sub-tank is performed with reference to the recording head having the high drive waveform appropriate voltage as a reference. It is characterized in that it is performed in the direction of lowering. As a result, the water head pressure acting on the ink surface always decreases, so that ink leakage caused by raising the water head can be avoided. In addition, since a change in ink discharge weight with a head difference is small in a recording head having a high drive waveform appropriate voltage, a large change in water head is necessary for a slight change in ink discharge weight, that is, a movable range becomes large. In this case, however, the range of motion can be minimized.

  According to an eighth aspect of the invention, in the ink jet recording apparatus according to any one of the first to seventh aspects, each head unit includes the recording head and the sub tank for all colors used for color printing. It is characterized by having. As a result, since all colors are included in one head unit at the time of making the head unit, positioning adjustment in the head unit is not necessary, and positioning adjustment may be performed for each head unit, thereby reducing man-hours. be able to.

  The invention according to claim 9 is characterized in that in the ink jet recording apparatus according to any one of claims 1 to 8, a common drive signal is supplied to each of the recording units. Thereby, a circuit can be made common and cost reduction can be aimed at.

  According to a tenth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to ninth aspects, a plurality of the main tanks are provided at different heights. Even when a plurality of recording heads are provided and the height of the sub-tank is greatly different, the water head difference between the sub-tank and the main tank can be made uniform, so that printing can be performed while stably supplying ink to the sub-tank.

  According to an eleventh aspect of the invention, in the ink jet recording apparatus according to any one of the first to tenth aspects, the nozzle forming surface of each recording head is sealed and the ink is sucked and discharged from the recording head. A cap unit is provided for each recording head. Furthermore, in the invention according to Claim 12, in the ink jet recording apparatus according to any one of Claims 1 to 11, the first flow path opening / closing means for controlling opening / closing of the ink flow path around each of the recording heads is It is characterized by being arranged for each ink flow path. Accordingly, cleaning can be performed for each recording head, and defective nozzles can be reliably and efficiently recovered.

  According to a thirteenth aspect of the present invention, in the ink jet recording apparatus according to the twelfth aspect, the first flow path opening / closing means is disposed on the cap unit side. Furthermore, in the invention according to claim 14, in the ink jet recording apparatus according to any one of claims 11 to 13, a negative pressure generating means for making the ink flow path negative is provided. It is a feature. As a result, no negative pressure is generated in the recording head that is not to be cleaned, so that the meniscus formed on the nozzle can be prevented from being destroyed. In particular, by using a desiccator as the negative pressure generating means, no depressurization curve is generated, so that the cleaning time can be shortened.

  According to a fifteenth aspect of the present invention, in the ink jet recording apparatus according to the fourteenth aspect, a plurality of the negative pressure generating means are provided, and a second flow path is provided for each of the ink flow paths on the negative pressure generating means side. An opening / closing means is provided. As a result, the negative pressure for each recording head can be adjusted, so that not only a desiccator but also a tube pump can be used as the negative pressure generating means, and the cleaning time can be shortened, and defective nozzles can be effectively used. Can be recovered.

  According to a sixteenth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to fifteenth aspects, the recording head movable in the arrangement direction of the recording heads and disposed in a movable region. A wiper unit for wiping the nozzle forming surface is provided. Thereby, since the occupation space with respect to the apparatus of a wiper unit can be made small, the cost increase by the enlargement of an apparatus can be suppressed.

  The invention according to claim 17 is the method for adjusting an ink jet recording apparatus, wherein the recording head is mounted on a carriage and reciprocated in the width direction of the recording medium and ejects ink droplets onto the recording medium, together with the recording head An adjustment method for an ink jet recording apparatus, wherein the head unit is mounted on the carriage so that position adjustment is possible, and a plurality of head units each having a sub tank for receiving ink supply from the main tank and supplying the ink to the recording head are provided. The position of the sub tank is adjusted during recording on the recording medium by the recording head.

  According to an eighteenth aspect of the present invention, in the adjustment method for an ink jet recording apparatus according to the seventeenth aspect, the position of the sub tank is finely adjusted at the stage of assembly with the carriage. In the invention according to claim 19, in the adjustment method of the ink jet recording apparatus according to claim 18, the fine adjustment of the position of the sub tank is performed according to the drive waveform appropriate voltage displayed for each of the recording heads. It is a feature.

  In an invention according to claim 20, in the adjustment method of the ink jet recording apparatus according to claim 19, storage means for storing the driving waveform appropriate voltage for each recording head, and the storage means to the recording head for each recording head. An adjustment means for finely adjusting the position of the sub tank by reading an appropriate driving waveform voltage, and a table for storing an adjustment value of the position of the sub tank corresponding to the appropriate driving waveform voltage for each recording head; The means performs fine adjustment based on the adjustment value of the position of the sub tank selected from the table in accordance with the drive waveform appropriate voltage for each of the recording heads read from the storage means.

  In the invention according to claim 21, in the adjustment method of the ink jet recording apparatus according to claim 19 or 20, the fine adjustment of the position of the sub-tank lowers the water head with reference to the recording head having the high drive waveform appropriate voltage. It is characterized by being done in the direction. The invention according to claim 22 is characterized in that, in a program executable by a computer, the method for adjusting an ink jet recording apparatus according to any one of claims 17 to 21 is constructed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a configuration example of an ink jet printer according to an embodiment of an ink jet recording apparatus of the present invention. An ink jet printer 200 shown in FIG. 1 is a large ink jet printer capable of printing up to a relatively large size printing paper (roll paper R) such as JIS standard A0 size or JIS standard B0 size. A paper feeding unit 210, a printing unit 220, and a paper discharge unit 230 are arranged from the upper side of the printer main body 250 toward the lower side of the leg part 240.

  The paper feed unit 210 includes a roll paper holder 211 on which roll paper R before printing can be set. The roll paper holder 211 includes a spindle 212 for holding the roll paper and a pair of spindle receivers 213 and 214 on which the spindle 212 can be attached / detached and suspended. Are disposed between the support pillars 215. After the roll paper R is mounted at the center of the spindle 212, both ends of the spindle 212 are mounted on the spindle receivers 213 and 214 so as to be rotatably supported.

  The paper discharge unit 230 includes a winding holder 231 capable of winding the rolled paper R after printing. The take-up holder 231 includes a spindle 232 for taking up the roll paper R on which printing has been completed, and a pair of spindle receivers 233 and 234 on which the spindle 232 can be attached and detached and suspended. Between the two support columns 242 having the roller 241. Both ends of the spindle 232 are mounted on spindle receivers 233 and 234, and are rotatably supported by driving means (not shown).

  The printing unit 220 is stored in the printer main body 250 and is covered with an upper lid 220a and a front lid 220b attached to the upper and front surfaces of the printer main body 250. Details will be described with reference to FIG. FIG. 2 is a partial cross-sectional side view of the ink jet printer 200 shown in FIG. A paper conveyance path from the paper supply unit 210 to the paper discharge unit 230 via the printing unit 220 is provided to be inclined from the upper rear surface side to the lower front surface side of the ink jet printer 200.

  On this sheet conveyance path, in order from the sheet feeding unit 210 side, a sheet feeding guide 221, a contact / separable sheet feeding roller 222 and a driven roller 223, and a plurality of inkjet type mounted on the carriage 1 are arranged. A recording head 6, a printing stage 224 disposed opposite to the recording head 6, a sheet discharge guide 225, and a sheet discharge roller 226 disposed opposite to the sheet discharge guide 225 are disposed.

  The paper feed guide 221, the printing stage 224, and the paper discharge guide 225 function as a paper transport surface and are each formed flat. Accordingly, the roll paper R from the paper feed guide 221 to the paper discharge guide 225 via the printing stage 224 is conveyed while being flat.

  3 is a top view of the printing unit 220, FIG. 4 is a plan view showing the periphery of the carriage 1, and FIG. 5 is a cross-sectional side view taken along line AA of FIG. As shown in FIG. 3, the carriage 1 is guided by a scanning guide member 4 via a timing belt 3 driven by a carriage motor 2, and is in the longitudinal direction of the printing stage 224, that is, the main scanning direction which is the width direction of the recording paper. It is designed to move back and forth.

  As shown in FIGS. 3 to 5, the carriage 1 includes a head unit 10 having a recording head 6 (not shown in FIG. 3) and a sub tank 7 for supplying ink to the recording head 6. 4 × 4 (partially 5) are arranged in the scanning direction and the sub-scanning direction. Note that the number of arrangement of the head units 10 is not particularly limited to 4 × 4 (partially 5), and may be any number. As shown in FIG. 1, a main tank 9 for supplying ink to the sub tank 7 is loaded in the cartridge holder 8 disposed at the end of the apparatus main body.

  As shown in FIGS. 4 and 5, each recording head 6 is mounted on the side of the carriage 1 facing the paper feeding member 5, and each sub tank 7 is placed on the carriage 1 above the corresponding recording head 6. It is installed. In this example, since the number of sub tanks 7 is larger than the space on the carriage 1, the sub tanks 7 are separately mounted on two-stage plates 1 a and 1 b disposed on the carriage 1. The plates 1a and 1b are not limited to two stages, and one or three or more stages of plates can be arranged depending on the number of sub tanks 7. Further, the sub tank 7 and the head unit 10 may be integrated and fixed on the carriage 1. This further facilitates replacement maintenance.

  Each sub-tank 7 is provided with an actuator 17 for moving each sub-tank 7 in the direction indicated by the arrow a, that is, in the height direction. The actuator 17 is disposed to adjust the head pressure generated by the head difference between the ink surface in the sub tank 7 and the nozzle formation surface of the recording head 6 and adjust the ink discharge weight of the recording head 6. The actuator 17 is composed of, for example, a ball screw / nut having a motor, an air cylinder, a hydraulic cylinder, or the like. In addition, a sensor using a Hall element that adjusts the ink liquid level can also be used as means for adjusting the water head difference.

  By performing the adjustment by the actuator 17 during printing, the amount of ink ejected from the nozzles can be made uniform particularly during the printing process at the upper and lower ends of the recording paper, and the printing accuracy can be further improved. Further, by performing fine adjustment by the actuator 17 when the sub tank 7 is incorporated in the carriage 1, the amount of ink ejected from the nozzles can be made uniform to some extent in the initial stage. The dynamic pressure can be adjusted stably over a wide range depending on the sub-tank position during printing. Further, in the present embodiment, one actuator 17 is provided in the sub tank 7, but it may be provided as many as the number of sub tanks constituting each color. As a result, the height can be adjusted according to the ink surface of the sub tank for each color, so that the print quality can be further improved.

  Here, since the dynamic pressure of the recording head 6 varies from head to head, as shown in FIG. 6, the head is determined by the drive waveform appropriate voltage VH of the recording head 6 as well as the inclination of the head difference h-ink discharge weight Iw. It depends on the ID. This drive waveform appropriate voltage VH is a voltage that is solid, that is, a voltage at which the ink weight is optimal at the time of full duty printing. Therefore, the recording heads 6 in the A area, the B area, and the C area are selected and used, and the adjustment value of the water head difference h is selected to adjust the position of the sub tank 7. As a result, the characteristics of each recording head 6 can be made uniform, so that the recording head 6 to be incorporated in the carriage 1 can be selected even if the characteristics of the recording head 6 vary greatly, and the head driver can be shared. And cost can be greatly reduced.

  Further, when the recording head 6 having the lowest driving waveform appropriate voltage VH, that is, the recording head 6 from which ink is often generated at the same voltage, is used as a reference, the other recording heads 6 have the same voltage and the ink discharge amount is small. Needs to be adjusted in the direction of raising from the reference position. If the nozzle position and the ink surface height of the sub tank 7 are not higher, the ink drips. Therefore, there is a limit to the height at which the sub tank 7 can be raised. On the other hand, for example, as shown in FIG. 7, when the recording head 6 having the highest driving waveform appropriate voltage VH, that is, the recording head a where the ink is not generated with the same voltage, is used as a reference, the water head difference h decreases in the direction of decreasing from the reference position. Adjust it. The recording head b having a lower appropriate voltage has a larger change in dynamic pressure when the height of the sub tank 7 is changed. Further, since the adjustment is performed by lowering the sub tank 7, the ink does not drip from the nozzles by the adjustment. The same applies to the adjustment at the time of printing because the sub tank 7 is lowered.

  In particular, since the number of nozzles used when performing upper and lower end processing on recording paper is smaller than the number of nozzles used in normal times, the dynamic pressure of the flow path decreases, and the ink discharge weight also increases by about 5% to 7%. By preparing a table in which the water head adjustment value H is written in advance according to the number of nozzles, the position of the sub tank 7 can be adjusted with reference to the table.

  The actuator 17 is provided as a means for adjusting the water head difference between the ink surface in the sub tank 7 and the nozzle formation surface of the recording head 6, but the present invention is not limited to this, and a long hole is provided in the sub tank 7. Alternatively, the height of the sub tank 7 may be determined and then screwed to the carriage 1. Further, means for changing the positions of the hall elements 33a and 33b (see FIG. 9) provided in the sub tank 7 described later may be provided.

  FIG. 8 is a cross-sectional view showing details of the recording head 6. As shown in FIG. 8, the recording head 6 includes a flow path unit 161 and a piezoelectric vibration unit 162. The flow path unit 161 includes a nozzle plate 163 in which a plurality of nozzle openings 163a are formed as nozzle rows, a pressure generation chamber 164a that communicates with the nozzle openings 163a, and a reservoir 164c that supplies ink to the pressure generation chambers 164a. The flow path forming substrate 164 and the elastic plate 165 that abuts on the tip of each piezoelectric vibrator 162a in the longitudinal vibration mode of the piezoelectric vibration unit 162 to expand and contract the volume of the pressure generating chamber 164a are integrally laminated. Has been.

  The piezoelectric vibration unit 162 is connected to a flexible cable 166 that transmits a driving signal from the outside, and is housed in a housing chamber 167a of a holder 167 formed by injection molding of a polymer material, and is fixed by an adhesive. Furthermore, the holder 167 and the flow path unit 161 are fixed with an adhesive. The holder 167 is formed with an ink guide path 167b that communicates with an external ink tank (not shown), the tip of which is connected to the ink introduction port 167c of the flow path unit 161, and the ink from the sub tank 7 receives the flow path unit 161. To be supplied. A frame (frame) 168 also serving as a shield material is inserted into the integrated holder 167 and the flow path unit 161 on the nozzle plate 163 side, and the recording head 6 is configured.

  Each piezoelectric vibrator 162a in the longitudinal vibration mode that constitutes the piezoelectric vibration unit 162 has, for example, an electrode serving as one pole and an electrode serving as the other pole laminated in a sandwich shape via a piezoelectric material, although not illustrated. , One electrode is exposed to the front end side, and the other electrode is exposed to the rear end side, and is configured as a piezoelectric constant d31 connected to the segment electrode and the common electrode at each end face, and the arrangement pitch of the pressure generating chambers 164a The piezoelectric vibration unit 162 is fixed to the fixed substrate 169 so as to match.

  A segment electrode and a common electrode (not shown) of each piezoelectric vibrator 162a of the piezoelectric vibration unit 162 are connected to a conductive pattern for driving signal transmission of the flexible cable 166 via a solder layer. As the drive signal, a common signal is supplied to each recording head 6, whereby the ink droplet landing position deviation for each recording head 6 can be adjusted independently.

  Since the ink jet printer 200 in this example is a model that uses inks of six colors of black, yellow, magenta, light magenta, cyan, and light cyan, as shown in the enlarged plan view of FIG. A configuration of 2 rows × 3 heads 6ab, 6cd, 6ef is formed by combining three nozzle rows 6n formed in two rows per head.

  The recording head 6 is not limited to the 2 rows × 3 heads 6ab, 6cd, 6ef, and can correspond to any number of nozzle rows and the number of heads. As shown in FIG. 3, the sub tank 7 and the main tank 9 are provided with six tanks 7 a to 7 f and 9 a to 9 f corresponding to each ink in order to temporarily store the six colors of ink inside. It has become.

  3 and 5, each recording head 6 and each sub tank 7a-7f are connected by an ink supply tube 11, and as shown in FIG. 3, each sub tank 7a-7f and each main tank 9a. 9 f is connected by an ink supply tube 12. Thereby, the six color inks in the main tanks 9a to 9f are supplied to the sub tanks 7a to 7f via the ink supply tube 12, and the six color inks in the sub tanks 7a to 7f are supplied to the ink supply tube 11. Is supplied to each recording head 6 via the.

  As described above, since all the colors used for color printing, that is, the above six colors are included in one head unit when the head unit 10 is formed, the recording head 6 and the sub tank 7 are included in one head unit. It is sufficient to presume that the positioning of the head unit 10 is surely performed, and it is only necessary to adjust the positioning for each head unit 10.

  Note that all colors used for color printing are not limited to the above six colors. For example, four colors of black, yellow, magenta, and cyan or black, dark yellow, yellow, magenta, light magenta, cyan, and light cyan are used. It is also applicable to seven colors of black, light black, yellow, magenta, light magenta, cyan and light cyan.

  As described above, since the head unit 10 having a large number of recording heads 6 and sub-tanks 7 is arranged on the carriage 1, the throughput for a large-sized recording medium can be improved. In addition, since each head unit 10 is independent, it is possible to select and mount the recording heads 6 having a certain degree of characteristics on the carriage 1, and there is a difference in the characteristics of each recording head 6. However, since the characteristics of each recording head 6 can be made uniform by adjusting the water head difference with each sub tank 7, uniform recording image quality can be obtained. Further, when the characteristics of the recording head 6 are deteriorated, the head unit 10 having the recording head 6 having the predetermined characteristics can be easily replaced, so that maintenance work is facilitated and the recording accuracy is high. Can continue to maintain.

  As shown in FIG. 3, a cap unit 15 is disposed in a non-printing area (home position) on the movement path of the carriage 1. In the cap unit 15, cap members 15a formed of a flexible material such as rubber capable of sealing the nozzle formation surface of each recording head 6 are arranged in an array of the heads 6ab, 6cd, 6ef of each recording head 6. Correspondingly, a plurality (in this example, 3 × 4 × 4) are arranged. Thus, when the carriage 1 moves to the home position, the nozzle forming surface of each recording head 6 is sealed by each cap member 15a on the cap unit 15 that follows the carriage 1, and the rest period of the ink jet printer 200 is reached. It is possible to prevent the nozzle openings of each recording head 6 from being dried.

  In addition, it is not limited to 1 head 1 cap, For example, the structure of 3 head 1 cap may be sufficient. In this example, each head 6ab, 6cd, 6ef is a set of two colors, and two colors of ink are mixed in each cap member 15a at the time of regular flushing. Can be prevented.

  As shown in FIG. 3, a wiper unit 16 formed of an elastic material such as rubber and having a driving stroke in the sub-scanning direction indicated by an arrow S is disposed on the printing area side adjacent to the cap unit 15. . Thereby, the nozzle formation surfaces of the plurality of recording heads 6 can be selectively and efficiently wiped and cleaned.

  In addition, since the space occupied by the wiper unit 16 with respect to the ink jet printer 200 can be reduced, an increase in cost due to an increase in size of the ink jet printer 200 can be suppressed. Although the wiper unit 16 is configured to be used for wiping the plurality of recording heads 6 in the moving region, the wiping unit 16 is not limited to this, and the wiping is performed for each head 6ab, 6cd, 6ef or for each recording head 6. It may be configured for use.

  FIG. 9 is a diagram schematically showing an ink supply system mounted on the ink jet printer 200 of FIG. Note that FIG. 9 shows a configuration for one color for convenience. As shown in FIG. 9, the pressurized air generated by the pressurizing pump 21 is supplied to the pressure regulating valve 22, and the pressurized air whose pressure is regulated by the pressure regulating valve 22 passes through the pressure detector 23 to the main tank 9. To be supplied.

  Here, the main tank 9 has an outer shell formed in an airtight state, and an ink pack 24 formed of a flexible material filled with ink is accommodated in the main tank 9. A space formed by the outline of the main tank 9 and the ink pack 24 forms a pressure chamber 25, and pressurized air is supplied into the pressure chamber 25 via the pressure detector 23. ing.

  As a result, the ink pack 24 stored in the main tank 9 is pressurized by the pressurized air and acts so that an ink flow is generated from the main tank 9 to the sub tank 7. Therefore, the ink pressurized in the main tank 9 is supplied to the sub tank 7 mounted on the carriage 1 through the ink supply valve 26 and each ink supply tube 12.

  Here, the sub tank 7 has a float member 31 disposed therein, and a permanent magnet 32 is attached to a part of the float member 31. Magnetoelectric conversion elements 33 a and 33 b typified by Hall elements are attached to the substrate 34 and are attached to the side walls of the sub tank 7. Thereby, the magnetic lines of force of the permanent magnet 32 act on the Hall elements 33a and 33b in accordance with the floating position of the float member 31 corresponding to the amount of ink in the sub tank 7.

  Therefore, the ink amount in the sub tank 7 can be detected by the electrical output of the Hall elements 33a and 33b. For example, when the amount of ink in the sub tank 7 decreases, the position of the float member 31 accommodated in the sub tank 7 moves in the direction of gravity, and accordingly, the position of the permanent magnet 32 also moves in the direction of gravity. Therefore, the ink supply valve 26 is opened by the electrical output of the Hall elements 33a and 33b due to the movement of the permanent magnet 32, and the ink pressurized in the main tank 9 enters the sub-tank 7 where the ink amount has decreased. Sent out.

  When the ink amount in the sub tank 7 reaches a sufficient amount, the ink supply valve 26 is closed based on the electrical output of the hall elements 33a and 33b. By repeating such operations, the main tank 9 acts to be replenished with ink to the sub tank 7 intermittently, and each sub tank 7 always stores a substantially constant range of ink. .

  In this way, the ink pressurized by the air pressure in the main tank 9 is replenished to the sub tank 7 based on the electrical output based on the position of the float member 31 disposed in the sub tank 7. Since it is configured, the ink supply response can be improved, and the amount of ink stored in the sub tank 7 is appropriately managed.

  Ink is supplied from the sub tank 7 to the recording head 6 through a valve unit 35 as a flow path opening / closing means and an ink supply tube 36 connected thereto. Then, based on print data given to an actuator (not shown) of the recording head 6, ink droplets are ejected from the nozzle openings 6a on the nozzle formation surface of the recording head 6.

  Here, the recording heads 6 and the sub tanks 7 for all the colors are integrally configured, and the recording heads 6 for all the colors of the integrated configuration themselves are joints in which the ink supply tubes 36 are disposed in the vicinity of the valve unit 35. It can be separated from the carriage 1 and removed from the carriage 1. Thereby, each recording head 6 can be removed from the carriage 1 and maintenance can be easily performed.

  The cap unit 15 is connected to one end of a suction tube 37a to which a plurality of suction pumps 37 such as a desiccator as negative pressure generating means are connected. A valve unit 15V as a first flow path opening / closing means is connected to the cap member 15a side of the suction tube 37a, and a valve as a second flow path opening / closing means is connected to each suction pump 37 side of the suction tube 37a. Unit 37V is connected.

  Accordingly, the negative pressure by the suction pump 37 is applied to each of the heads 6ab, 6cd, 6ef of each recording head 6, and the ink is sucked from the heads 6ab, 6cd, 6ef of each recording head 6 and discharged to the waste liquid tank 38. Processing can be performed. In particular, when defective nozzles occur in some of the heads 6ab, 6cd, 6ef, the defective nozzles can be reliably and efficiently recovered by opening the valve unit 15V that leads only to the corresponding heads 6ab, 6cd, 6ef. In addition, since no negative pressure is generated in a good nozzle, the meniscus formed on the nozzle can be prevented from being destroyed. Further, wasteful ink consumption can be prevented by the selective cleaning process.

  In addition, since a plurality of suction pumps 37 are connected, by selecting the valve unit 37V to be opened, the negative pressure generation force can be changed as appropriate, for example, by switching between minute suction and large suction immediately. Fine cleaning can be performed. Furthermore, since a desiccator is used as the suction pump 37, a decompression curve does not occur and the cleaning time can be shortened. Note that a tube pump or the like as well as a desiccator may be used as the negative pressure generating means. Further, a plurality of negative pressure generating means for generating the same negative pressure may be provided, or a plurality of negative pressure generating means for generating different negative pressures may be provided.

  Further, if the valve unit 15V is closed when the ink jet printer 200 is turned off and the cap member 15a is filled with ink by flushing, a moisturizing effect can be ensured and clogging due to ink can be prevented. . In this example, each of the heads 6ab, 6cd, and 6ef is a set of two colors, but the cleaning process can be performed more effectively by using a staggered arrangement of nozzles and a head configuration for each color. Can do.

  Further, as shown in FIG. 10, a printing stage 224 having a plurality of small holes 224a perforated on the sheet conveying surface is connected to one end of a suction tube 37a to which a plurality of suction pumps 37 are connected. A valve unit 224V, which is a third flow path opening / closing means, is connected to the side of the printing stage 224 in the suction tube 37a.

  As a result, a negative pressure by the suction pump 37 is generated in the small hole 224a of the printing stage 224, and the roll paper R on the printing stage 224 is sucked and sucked onto the surface of the printing stage 224, so that the roll paper R is in a flat state. Can be held in. Therefore, the conveyance accuracy can be improved, and printing can be performed with higher accuracy.

  Further, for example, when the printing material is not a material that allows air to pass, such as paper, but a material that does not allow air to pass, such as a plastic film, it may stick to the surface of the printing stage 224 at the time of suction, which may cause a conveyance failure. At this time, by selecting the valve unit 37V to be opened, the negative pressure generating force can be appropriately changed, so that sticking at the time of suction can be prevented and the conveyance accuracy of the printed material can be improved. it can. As described above, by changing the generated force according to the type of the printing material, it is possible to stably convey the printing material. Moreover, it is good also as a structure which makes the pump 37 common and provides a regulator between valve | bulb 37V. The pressure corresponding to the regulator can be selected. By using the pump 37 in common, space saving and low cost can be achieved.

  In this manner, ink is sucked from the recording head 6 and discharged to the waste liquid tank 38, and ink is sucked, and the roll paper R on the printing stage 224 is sucked and sucked onto the surface of the printing stage 224. R suction can be performed by switching the valve units 15V, 224V, and 37V automatically or manually with a single suction pump 37, so that space can be saved and costs can be reduced.

  FIGS. 11 to 13 are views showing an embodiment of the sub-tank 7. FIG. 11 is a perspective view of the sub-tank 7 with a part of the structure omitted, and FIG. 12 shows the same direction. FIG. 13 is a rear view seen from the back direction. The sub-tank 7 is formed in a substantially rectangular parallelepiped shape, and is entirely flat. The outer shell of the sub tank 7 is composed of a box-like member 41 in which a side wall 41a and a peripheral side wall 41b connected to the side wall 41a are integrally formed. A member 42 (see FIG. 10) is attached in close contact with the heat welding means, and an ink storage space 43 is formed inside the box member 41 and the film member 42.

  A support shaft 44 that protrudes from one side wall 41 a constituting the box-shaped member 41 toward the ink storage space 43 is formed integrally with the box-shaped member 41, and the float member 31 rotates the support shaft 44. As a center, the ink storage space 43 is arranged so as to be movable in the direction of gravity. In this embodiment, the support shaft 44 is disposed in the vicinity of the horizontal end of the ink storage space 43, and the float member 31 is supported by a support arm member 45 that is movable around the support shaft 44. Are integrally formed on the movable free end side.

  As shown in FIG. 12, a permanent magnet 32 is attached to the free end side of the support arm member 45, and the permanent magnet 32 has an ink storage space when the support arm member 45 is in a substantially horizontal state. It is configured to be located in the vicinity of the other end portion in the horizontal direction at 43, that is, to be closest to the Hall elements 33 a and 33 b mounted on the substrate 34 attached to the side wall of the sub tank 7.

  The hall elements 33a and 33b are inserted into positioning recesses 41c formed on the side walls of the sub tank 7. By forming the positioning recesses 41c, the side walls of the sub tank 7 are made thinner, so that the float member The movement trajectory of the permanent magnet 32 attached to 31 and the distance between the hall elements 33a and 33b can be made closer.

  On the other hand, the sub tank 7 has an ink supply port 46 formed in the lower part in the gravity direction, that is, in the bottom of the peripheral side wall 41b in this embodiment, and the ink supply tube 12 connected to the ink supply port 46. Ink is replenished from the main tank 9 into the ink storage space 43. By forming the ink supply port 46 in the sub-tank 7 at the lower part in the direction of gravity, the ink from the main tank 9 is supplied from the bottom of the ink storage space 43. Consideration is given so that no ink bubbling occurs.

  Further, in the sub tank 7, a plurality of rib members 47 that reduce the degree of occurrence of ink undulation in the sub tank 7 with the movement of the carriage 1 in a portion that avoids the movement area of the float member 31 and the support arm member 45. Is arranged. In this embodiment, the rib member 47 is integrally formed with the one side wall 41 a as a base so as to protrude from the one side wall 41 a of the box-shaped member 41 constituting the sub tank 7 toward the ink storage space 43. However, this may be formed separately.

  The presence of the rib member 47 can reduce the degree of occurrence of ink undulations in the sub-tank 7, thereby improving the detection accuracy of the amount of ink stored in the sub-tank 7 by the Hall elements 33a and 33b. In addition, the ink amount in the sub tank 7 can always be kept constant, and the water head difference between the upper surface of the ink in the sub tank 7 and the nozzle formation surface of the recording head 6 can be made constant. For example, by providing a sub-tank that can store only the ink amount that can be recorded on A0 size paper, the above-described ink storage amount detecting means in the sub-tank 7 may not be provided, and the manufacturing cost is reduced. Can be made.

  In addition, an ink outlet port 48 is formed in the sub tank 7 in the vicinity of the ink supply port 46. A filter member 49 for trapping foreign matter that forms a pentagon (home base shape) is disposed so as to cover the ink outlet 48, and therefore, the ink stored in the sub tank 7 passes through the filter member 49. Thus, the ink is led to the ink outlet 48. In addition, since the ink outlet 48 is formed in the vicinity of the ink supply port 46, the relatively new ink introduced into the sub tank 7 acts so as to be immediately led out from the outlet 48.

  As shown in FIG. 13, the ink led out from the ink outlet 48 is led out to the groove portion 50 formed on the back surface of the side wall 41a, and is formed by the film-like member 51 thermally welded so as to cover the groove portion. It is configured to reach the valve unit 35 disposed at the lower bottom portion of the sub tank 7 through the ink outlet path. Then, an ink lead-out path (also denoted by the same reference numeral) is formed through the valve unit 35 and is formed into a groove 52 formed on the back surface of the side wall 41a and thermally welded so as to cover the groove 52. Through the connection port 53 of the ink supply tube 36 connected to the recording head 6.

  On the other hand, as shown in FIGS. 11 and 12, the upper half of the sub-tank 7 is formed with a conducting groove 61 that conducts to the ink storage space 43 in an inclined state. 7 is formed with an air communication port 62 that contributes to the back surface of the side wall 41a of the sub tank 7. As shown in FIG. 13, the air communication port 62 is disposed on the back surface of the sub tank 7 and is closed by a water repellent film 63 that is formed in a substantially rectangular shape that allows air to pass and prevents ink from passing.

  The water repellent film 63 is disposed in a recess formed in the back surface of the side wall 41a of the sub tank 7, and is held by a film member 64 that is heat-welded so as to cover the upper back surface of the side wall 41a. ing. A meandering groove 65 is formed on the back surface of the side wall 41 a through the water repellent film 63, and an end of the meandering groove 65 communicates with a bottomed hole 66 formed in the side wall 41 a of the sub tank 7. Yes. The meandering groove 65 and the bottomed hole 66 are covered with the film member 64 in an airtight state. Therefore, the air circulation resistance path (reference numeral 65 is the same as that of the meandering groove) due to the meandering groove 65 and the film member 64. Is formed.

  Then, by destroying the film-like member 64 covering the bottomed hole 66 with a sharp tool or the like, the atmosphere opening 62 is communicated with the atmosphere via the air circulation resistance path 65 formed in a meandering shape. Made. As described above, since the air communication port 62 formed in the sub tank 7 is covered with the water repellent film 63, the water repellent film 63 is formed when the entire recording apparatus is mistakenly turned upside down. The problem of leakage of ink in the sub tank 7 due to the presence can be avoided.

  Further, the bottomed hole 66 formed at the end of the air flow resistance path 65 is configured to be covered in an airtight state by the film member 64 in advance, so that the subtank liquid leakage (ink leakage) is completed when the subtank is completed. ) Can be checked, and when this check is completed, the film-like member 64 covering the bottomed hole 66 can be destroyed to provide the original function. A through hole 67 is formed in the sub tank 7, and the sub tanks 7 are supported in a parallel state by a single support shaft (not shown) that supports the sub tank 7 through the access hole 67. The sub tank unit can be configured.

  FIG. 14 is an exploded perspective view showing a detailed configuration of the float member 31. As shown in FIG. 14, the float member 31 includes a box-shaped member 71 in which one side wall 71 a and a peripheral side wall 71 b connected thereto are integrally formed, and the opening of the box-shaped member 71 is closed to make the inside hollow. It is comprised by the closure member 72 formed in a shape. As the closing member 72, a film-like member formed of a transparent resin is used, and the film-like closing member 72 is attached in close contact with the peripheral edge of the opening of the box-like member 71 by, for example, heat welding means, Thereby, the inside is formed in a hollow state.

  The float member 31 formed in this way is integrally formed on the movable free end side of the support arm member 45 that is movable around the support shaft 44 formed in the sub tank 7. A support ring 73 is integrally formed at the base end portion of the support arm member 45, and the support ring 73 is rotatably attached to the support shaft 44, so that the support shaft 44 is used as a rotation center. It is configured to be supported. And the permanent magnet 32 is attached to the free end side of the support arm member 45, and this permanent magnet 32 is covered with the film-like member 74 stuck on the surface, and is stored in the sub tank 7. The chemical adverse effects caused by the ink used are avoided.

  Further, positioning pins 75 are formed on a part of the float member 31 and the support arm member 45 so as to protrude in the horizontal direction on both outer sides at three locations. These positioning pins 75 desirably protrude from the both side surfaces of the float member 31 by 1 mm or more, so that a distance of at least 1 mm is maintained between the float member and the support arm member and the inner wall of the sub tank 7. Works. As a result, the problem that the surface tension of the ink acts between the float member 31 and the inner wall of the sub tank 7 to hinder the movement of the float member 31 can be solved.

  FIG. 15 is an enlarged cross-sectional view showing a valve unit 35 as a channel opening / closing means arranged in the sub tank 7. The structure shown in this figure is the same for the valve units 15V and 37V. As shown in FIG. 15, the valve unit 35 is disposed between the sub tank 7 serving as an ink reservoir and the recording head 6 and has a function of controlling opening and closing of the ink supply path to the recording head 6.

  When the valve unit 35 is in the closed state, a negative pressure is applied from the suction pump 37 to the cap unit 15 in a state where the nozzle forming surface of the recording head 6 is sealed, and the valve is fully accumulated in the negative pressure. The unit 35 is controlled to open. By this control, the ink functions instantaneously in the ink flow path from the sub tank 7 to the nozzle opening 6a of the recording head 6 and effectively discharges bubbles remaining in the ink flow path.

  The valve unit 35 uses a diaphragm valve 35a made of a flexible material such as a rubber material. The diaphragm valve 35a is attached so that the peripheral portion is sandwiched between a box-like member 41 constituting the sub tank 7 and a cylinder member 35c attached to the box-like member 41 with screws 35b. Yes. One end of a rod member 35d as an actuating body is attached to the lower surface side of the diaphragm valve 35a in the direction of gravity, and the diaphragm valve 35a receives the driving force in the axial direction of the rod member 35d and is substantially at the center. Is configured to be deformed in a direction orthogonal to the surface direction.

  The rod member 35d is configured to be movable in the vertical direction in the cylinder member 35c, and includes a disc-like body 35e formed on the rod member 35d and a spring receiving member 35f disposed on the inner bottom portion of the cylinder member 35c. The central portion of the diaphragm valve 35a is urged so as to protrude upward as indicated by the chain line by the action of the coiled spring 35g disposed therebetween. The upper surface side in the gravity direction of the diaphragm valve 35 a constitutes an open / close control chamber 35 h for the ink supply path from the sub tank 7 toward the recording head 6. An outlet opening 35i in the opening / closing control chamber 35h from the opening / closing control chamber 35h toward the recording head 6 is formed almost immediately above the center of the diaphragm valve 35a.

  Further, an annular contact surface 35n is formed around the outlet opening 35i in the opening / closing control chamber 35h so as to contact an annular convex portion described later formed in the diaphragm valve 35a. Then, an inclined surface 35j whose diameter decreases in the antigravity direction is formed continuously around the annular contact surface 35n. In this example, the inclination angle of the inclined surface 35j is about 45 degrees with respect to the direction of gravity, and the inclination angle of the inclined surface 35j is in the range of about ± 15 degrees with respect to 45 degrees. Is desirable.

  On the other hand, an inlet opening 35k extending from the sub tank 7 to the opening / closing control chamber 35h is formed at a position avoiding a position directly above the central portion of the diaphragm valve, that is, a part of the inclined surface 35j. Further, an annular convex portion 35m is integrally formed at a substantially central portion of the diaphragm valve 35a facing the opening / closing control chamber 35h side, and the annular convex portion 35m is formed by the upward deformation of the diaphragm valve 35a. The outlet opening 35i can be closed by contacting an annular contact surface 35n formed around the outlet opening 35i.

  In the above configuration, the central portion of the diaphragm valve 35a is normally deformed so as to protrude upward under the action of the spring member 35g and is formed at the central portion of the diaphragm valve 35a as shown by the chain line in FIG. The annular convex portion 35m is brought into contact with an annular contact surface 35n formed in the opening / closing control chamber 35h so as to close the outlet opening 35i.

  When printing is performed by the recording head 6, the rod member 35d receives a driving force of an actuator (not shown) and is pulled downward, whereby the normally closed diaphragm valve 35a is moved to the open / close control chamber 35h. The formed outlet opening 35i is opened to be opened. Further, the diaphragm valve 35a is controlled to be opened in a state where the nozzle forming surface of the recording head 6 is sealed by the cap unit 15 and the negative pressure is accumulated even when the cleaning operation of the recording head 6 is executed.

  The valve unit 35 configured as described above can be opened by slightly pulling the central portion of the diaphragm valve 35a downward by the rod member 35d, and by releasing the rod member 35d. The diaphragm valve 35a can be closed. Therefore, the operating force of the actuator required for the opening / closing valve operation of the valve unit 35 is very small.

  The valve unit 35 is closed when the nozzle forming surface of the recording head 6 is sealed by the cap unit 15 and receives a negative pressure from the suction pump 37, and the ink from the diaphragm valve 35 a to the recording head 6 is closed. The valve is opened while the flow path is accumulated in a negative pressure. By following such an operation sequence, immediately after the valve unit 35 is opened, a fast ink flow can be instantaneously generated in the ink flow path. Air bubbles remaining in the opening / closing control chamber 35h can be discharged to the cap unit 15 side.

  In this case, the valve unit 35 is formed with an opening / closing control chamber 35h at the upper part of the diaphragm valve 35a in the direction of gravity, and the outlet opening 35i from the opening / closing control chamber 35h toward the recording head 6 is directly above the central portion of the diaphragm valve 35a. Since the inclined surface 35j having a smaller diameter in the anti-gravity direction is formed around the outlet opening 35i, bubbles remaining in the opening / closing control chamber 35h are guided to the vicinity of the outlet opening 35i by the levitation action. can do. Thereby, it becomes possible to further enhance the discharge effect of the residual feeling.

  Further, an annular convex portion 35m formed at substantially the center portion of the diaphragm valve facing the opening / closing control chamber 35h is brought into close contact with the annular contact surface 35n formed in the opening / closing control chamber 35h and heads toward the recording head 6. Since it acts so as to close the outlet opening 35i, the annular convex portion 35m forms a flexible sealing surface, and a reliable on-off valve operation can be obtained in accordance with the linear movement operation of the rod member 35d. The annular contact surface 35n is a flat surface, and the width of the surface is formed as small as possible so that the annular protrusion 35m can be in close contact with the diaphragm valve 35a when the diaphragm valve 35a is closed. Desirably, by adopting such a configuration, it is possible to enhance the discharge of the feeling induced by the inclined surface 35j.

  According to such a configuration, when a negative pressure is applied in the capping state of the recording head 6, the diaphragm valve 35a receives the negative pressure, further improving the sealing performance in the closed state, and maintaining a reliable valve closing function. To come. In addition, the use of the diaphragm valve makes it possible to minimize the volume change on the recording head 6 side due to the opening / closing valve operation, and destroys the ink meniscus formed in the nozzle opening 6a of the recording head 6. It can be avoided.

  FIG. 16 is a view showing another example of the valve unit 35, and is a cross-sectional view further enlarging the opening / closing control chamber 35h shown in FIG. The structure shown in this figure is the same for the valve units 15V and 37V. As shown in FIG. 16, an outlet opening 35i in the opening / closing control chamber 35h heading from the opening / closing control chamber 35h toward the recording head 6 is formed almost immediately above the center of the diaphragm valve 35a, and enters the opening / closing control chamber 35h from the ink reservoir. The inlet opening 35k in the open / close control chamber 35h is formed at a lower position in the direction of gravity with respect to the outlet opening 35i.

  In this way, by forming the inlet opening 35k at a lower position in the direction of gravity with respect to the outlet opening 35i, the inlet opening 35k is ordered from the inlet opening 35k to the upper outlet opening 35i in the opening / closing control chamber 35h. As a result, it is possible to generate the flow of the ink, and in accordance with this, it is possible to promote the discharge of bubbles remaining in the open / close control chamber 35h.

  The distance h between the annular contact surface 35n formed in the opening / closing control chamber 35h and the convex portion 35m of the diaphragm valve is configured to be 1.0 mm to 1.3 mm in the opened state of the diaphragm valve. It is desirable that When this distance h is less than 1.0 mm, a phenomenon occurs in which bubbles remaining in the opening / closing control chamber 35h are caught between the convex portion 35m of the diaphragm valve and the annular contact surface 35n. The degree of impairing the discharge of bubbles from 35h increases. Further, when the distance exceeds 1.3 mm, the change in the internal volume of the opening / closing control chamber 35h becomes large during the opening / closing operation of the diaphragm valve 35a, and in particular, an unnecessary pressure fluctuation is given to the recording head 6. There is no.

  On the other hand, the flow area of the ink outlet path 52 from the outlet opening 35i toward the recording head 6 in the opening / closing control chamber 35h is small in the immediate vicinity of the outlet opening 35i in the opening / closing control chamber 35h, and as the distance from the opening / closing control chamber 35h increases. It is configured to be large. With this configuration, the ink flow rate at the outlet opening 35i of the opening / closing control chamber 35h can be increased, and the discharge of bubbles in the opening / closing control chamber 35h can be improved.

  17 and 18 are cross-sectional views showing a partial configuration of the main tank 9 and a partial configuration of the cartridge holder 8, and FIG. 17 shows a state immediately before the main tank 9 is loaded into the cartridge holder 8. FIG. 18 shows a state in which the main tank 9 is loaded in the cartridge holder 8 (or a state in which the cartridge is removed from the cartridge holder 8).

  As shown in FIGS. 17 and 18, the ink outlet plug 101 of the ink pack 24 in which ink is sealed is attached to the end of the case 100 constituting the outer member of the main tank 9. The ink lead-out plug 101 is provided with a valve member 102 that is in contact with the connection plug on the cartridge holder 8 side and retracts in the axial direction to be opened. The valve member 102 is moved by the spring member 103. It is biased to advance in the axial direction.

  Then, the valve member 102 urged so as to advance in the axial direction by the spring member 103 is pressed against the annular packing member 104 in which a contributory hole is formed in the center, and as a result, shown in FIG. As described above, the ink outlet plug 101 is closed. The case 100 has a pressurized air inlet. The pressurized air introduction port is constituted by a cylindrical body 105 that forms an air passage communicating with the pressure chamber 25, and the cylindrical body 105 is integrally formed so as to protrude to the front end side of the main tank. ing.

  On the other hand, on the cartridge holder 8 side, an ink receiving connection plug 111 is formed so as to protrude from the center thereof. When the main tank 9 is loaded, the ink receiving connection plug 111 is brought into contact with the ink outlet plug 101 on the main tank 9 side to be in a valve open state. When the cartridge holder 8 is not loaded, the valve closing state is closed. It is configured to be retained.

  That is, the ink receiving connection plug 111 is slidably disposed so as to surround the outer periphery of the hollow needle 113 in which the ink introduction hole 112 is formed, and the cartridge holder 8 is not loaded. An annular sliding member 115 that moves to a position that closes the ink introduction hole 112 formed in the hollow needle 113 under the bias of the spring member 114 is provided.

  Therefore, in the case shown in FIG. 13 in which the main tank 9 is not loaded, the annular sliding member 115 advances under the urging force of the spring member 114 and passes through the ink introduction hole 112 formed in the hollow needle 113. Close and close the valve. Further, in the case shown in FIG. 14 in which the main tank 9 is loaded in the cartridge holder 8, the ink outlet plug 101 on the main tank 9 side comes into contact with the annular sliding member 115 and retracts it. The ink introduction hole 112 formed in the hollow needle 113 is exposed, and the valve is opened so that ink can be introduced.

  At this time, on the main tank 9 side, the distal end portion of the hollow needle 113 on the cartridge holder 8 side abuts on the valve member 102 through a through hole formed in the packing member 104 to retract the valve member 102 in the axial direction. In addition, the ink outlet plug 101 on the main tank 9 side is also opened. As a result, ink can be supplied from the main tank 9 to the cartridge holder 8 as shown by the arrows in FIG.

  At the same time, the cylindrical rest 105 constituting the pressurized air inlet on the cartridge 8 side also enters the annular packing member 122 in the pressurized air supply plug 121 arranged on the cartridge holder 8 side. As a result, the packing member 122 is tightly connected to the outer peripheral surface of the cylindrical body 105, and the pressurized air can be introduced into the pressure chamber 25 on the cartridge 8 side as indicated by an arrow in FIG.

  With the above configuration, when the main tank 9 is removed from the cartridge holder 8, the ink outlet plug 101 arranged on the main tank 9 side is closed as shown in FIG. Can be prevented from leaking. At the same time, since the ink receiving connection plug 111 on the cartridge holder 8 side is also closed, the backflow of ink from the sub tank 7 side can be prevented.

  FIG. 19 is a perspective view illustrating a partial configuration of the cartridge holder 8. The cartridge holder 8 is provided with a cover member 131 that is opened when the main tank 9 is attached and detached. That is, the cover member 131 is disposed in front of the opening of the cartridge holder 8, and the rotation shaft 131a is supported by a support hole formed on the apparatus main body (not shown). The cartridge holder is centered on the shaft 131a. 8 is configured so that the front surface of the opening can be opened (state shown by a solid line) or closed (state shown by a chain line).

Inside the cover member 131 in the closed state, a plurality of operation levers 132 are arranged corresponding to the main tanks 9 loaded in the cartridge holder 8.
A locking hole 132a is formed in the base end portion of the operation lever 132, and is rotatably supported by a support rod (not shown) inserted and supported in each locking hole 132a in each operation lever 132. ing.

  The operation lever 132 can be loaded or unloaded from the main tank 9 by rotating in the same direction as the opening direction of the cover member 131 in a state where the cover member 131 is opened. That is, when the main tank 9 is loaded in the cartridge holder 8, the main tank 9 is inserted into the cartridge holder 8 with the operation lever 132 rotated in the same direction as the opening direction of the cover member 131, and the operation lever 132 is operated. By raising 132, the pressing portion 132b formed on the operation lever 132 comes into contact with the front end of the main tank 9, and the main tank 9 is loaded on the cartridge holder 8 side by the principle of leverage.

  In the case of pulling out the main tank 9 loaded on the cartridge holder 8 side, the operation lever 132 is also rotated in the same direction as the opening direction of the cover member 131, which is not shown in the figure. It acts to push out the main tank 9 from the back side through a link rod engaged with a part of 132. Therefore, the main tank 9 pushed forward can be easily pulled out.

  The cartridge holder 8 is further provided with an electric switch 133 that detects opening of the cover member 131. The switch 133 is turned on in contact with the back surface of the cover member 131 in a state where the cover member 131 is closed. For example, a tact switch which is turned off in the state where the cover member 131 is opened is used. Yes.

  The tact switch 133 controls the energization of the electromagnetic plunger 91 in the pressure regulating valve 22 that also serves as an air release valve. The tact switch 133 is turned on when the tact switch 133 is on, that is, when the cover member 131 is closed. 91 can be energized, and acts to cut off the energization to the electromagnetic plunger 91 when the tact switch 133 is in an OFF state, that is, when the cover member 131 is opened.

  Therefore, when the main tank 9 is to be pulled out from the cartridge holder 8 when the operation power is supplied to the ink jet printer 200, for example, the electromagnetic plunger 91 is based on the opening of the cover member 131 provided in the cartridge holder 8. The power supply to is cut off. As a result, the pressure adjusting valve 22 that also serves as an air release valve is opened, and the pressurized air that is attached to the cartridge holder 8 and applied to the main tank 9 is instantaneously released. Accordingly, the outer member of the main tank 9 which is in a slightly expanded state under the action of the pressurized air returns to its original shape, so that it can be easily pulled out from the cartridge holder 8, and the main tank 9 can be easily operated. Also, problems such as damage to both the cartridge holder and the cartridge holder can be avoided.

  When pulling out the main tank 9 from the cartridge holder 8, the cylindrical body 105 constituting the pressurized air inlet formed in the main tank 9 is separated from the pressurized air supply plug 121 arranged on the cartridge holder 8 side. It is considered that the pressure chamber 25 of the main tank 9 is released to the atmosphere at the moment. Therefore, when the main tank 9 is pulled out from the cartridge holder 8, the pressurization to the main tank 9 is immediately eliminated, and the incompatibility such as the ink blowing due to the action of the remaining pressurized air is eliminated.

  However, it is preferable to use a means for releasing pressurized air based on the opening of the cover member 131 provided in the cartridge holder 8. That is, at the moment when the main tank 9 is about to leave the cartridge holder 8, the ink outlet plug 101 on the main tank 9 side is slightly smaller than the ink receiving connection plug 111 on the cartridge holder 8 side in a state where pressurized air is applied. A situation occurs in which In this situation, both the ink outlet plug 101 and the ink receiving connection plug 111 are open. Therefore, in the case where the means for releasing the pressurized air in conjunction with the opening of the cover member 131 is not used, it is possible that the ink will blow out at this moment.

  Further, when the main tank 9 that is not configured to open the pressurized air inlet formed in the main tank 9 when the main tank 9 is pulled out from the cartridge holder 8 is used, the cartridge holder Needless to say, it is extremely important to provide means for releasing the pressurized air based on the opening of the eight cover members 131. Further, it is desirable to configure the air pressurization pump to stop driving when the tact switch 133 based on the opening of the cover member 131 is turned off. By configuring in this way, it is possible to prevent the idling of the air pressurizing pump.

  20 and 21 are partial cross-sectional views in which the main part of the pressure regulating valve 22 that also serves as an atmosphere release valve is broken. FIG. 20 shows a state in which the pressure regulating valve functions, and FIG. An open state is shown. As shown in FIGS. 20 and 21, the on-off valve unit 81 includes an upper case 81a and a lower case 81b each having a space formed therein, and can be divided into upper and lower parts by the upper case 81a and the lower case 81b. It is configured as follows. And the diaphragm valve 82 is arrange | positioned in the junction part of the upper case 81a and the lower case 81b.

  The diaphragm valve 82 is formed by molding a rubber material into a disk shape, and its peripheral portion is sandwiched between the joint portions of the upper case 81a and the lower case 81b, and air in an airtight state in the space portion of the lower case 81b. A chamber 83 is formed. The lower case 81b is formed with a pair of connecting pipes 84a and 84b communicating with the air chamber 83. These connecting pipes 84a and 84b are connected to the air pressurizing pump 21 and the pressure detector 23, respectively. .

  Therefore, the pressurized air from the air pressurizing pump 21 is applied along the arrow shown in FIG. 21, and the pressurized air is further applied to the pressure detector 23 and each main tank 9 via the air chamber 83. To be made. In addition, a vent hole 84c is formed in the central portion of the lower case 81b, and the substantially central portion of the diaphragm valve 82 is configured to abut at the opening end of the vent hole 84c to the air chamber 83.

  On the other hand, the upper case 81 a is arranged so that the drive shaft 85 is slid in the vertical direction, and the upper surface portion of the diaphragm valve 82 is supported at the lower end portion of the drive shaft 85. An annular spring seat 86 is attached to the drive shaft 85, and a coiled spring member 87 is disposed between the spring seat 86 and the upper space of the upper case 81a. 87, the central portion of the diaphragm valve 82 is urged so as to contact the opening end of the vent hole 84c.

  An engagement head 88 is provided at the upper end portion of the drive shaft 85, and is a through-hole formed in the drive lever 90 that is pivotally supported by a support shaft 89 and rotated in a seesaw shape about the support shaft 89. The engaging head 88 is attached to the upper part that has contributed to the above. One end of the drive lever 90 is engaged with an operating rod 91a of an electromagnetic plunger 91 as drive means.

A spring member, that is, one end of a tension spring 93 is attached to the other end portion of the drive lever 90 via the support shaft 89, and the drive lever 90 is connected via the support shaft 89 by the action of the tension spring 93. It is biased to rotate counterclockwise in the figure.
An engagement head 88 of the drive shaft 85 of the on-off valve unit 81 is engaged with an intermediate portion between one end of the drive lever 90 that receives the driving force of the electromagnetic plunger 91 and the support shaft 89.

  When the electromagnetic plunger 91 is energized, one end of the drive lever 90 is pulled down against the urging force of the tension spring 93 as shown in FIG. Therefore, the engagement head 88 attached to the drive shaft 85 of the on-off valve unit 81 is brought into a state of floating from the drive lever 90. As a result, the diaphragm valve 82 is in a closed state in which the vent hole 84c is closed by the urging force of the spring member 87 and the elastic force held by the diaphragm valve 82.

  When the pressure in the air chamber 83 exceeds a predetermined value, the diaphragm valve 82 is pushed upward in the air chamber 83, whereby the contact of the diaphragm valve 82 with the vent hole 84c is released, and the pressure adjustment valve Function as. Thereby, the air pressure pressurized by the air pressurizing pump 21 functions to release the pressure that has reached an excessive state due to some trouble, and to maintain the air pressure applied to the main tank 9 within a predetermined range.

  On the other hand, when the energization of the electromagnetic plunger 91 is cut off, the drive lever 90 is rotated counterclockwise in the drawing by the action of the tension spring 93 as shown in FIG. The drive shaft 85 is pulled up against the urging force of the pinion member 87 in the on-off valve unit 81 and the elastic force held by the diaphragm valve 82. Therefore, the air chamber 83 is opened to the atmosphere in which pressurized air is released from the air chamber 83 through the vent hole 84c.

  As described above, when the energization of the electromagnetic plunger 91 is cut off, the air is released. Therefore, when the cover member 131 attached to the cartridge holder 8 is opened, the energization of the electromagnetic plunger 91 is cut off. By configuring, the air pressure applied to each main tank 9 with the opening of the cover member 131 is instantaneously released. Further, when the operation power of the ink jet printer 200 is turned off, the energization to the electromagnetic plunger 91 is also cut off, so that the pressure is automatically released in the rest state of the ink jet printer 200. As a result, when the ink jet printer 200 is not in use, the air pressure applied to the main tank 9 is released, and during the rest of the ink jet printer 200, for example, the leakage of ink from the main tank 9 is induced by the residual air pressure. Can be avoided.

  FIG. 22 is a block diagram showing a configuration of a control circuit mounted on the ink jet printer 200. As shown in FIG. 20, the print control means 170 generates bitmap data based on print data supplied from the host computer, and generates a drive signal by the head drive means 171 based on this bitmap data. Ink droplets are ejected from the recording head 6. In addition to the drive signal based on the print data, the head drive unit 171 receives a flushing command signal from the flushing control unit 172 and outputs a drive signal for the flushing operation to the recording head 6.

  The cleaning control unit 173 operates the pump driving unit 174 to drive and control the suction pump 37. The cleaning control unit 173 is supplied with a cleaning command signal from the printing control unit 170, the cleaning sequence control unit 175, and the cleaning command detection unit 176. A cleaning command switch 177 is connected to the cleaning command detection unit 176. When the user pushes the cleaning command switch 177, for example, the cleaning command detection unit 176 is operated to perform a manual cleaning operation. It has come to be.

  The cleaning sequence control unit 175 receives a command signal from the host computer and sends a control signal to the cleaning control unit 173, the valve unit driving unit 178, and the carriage driving unit 179. The valve unit driving means 178 drives an actuator (not shown) that pulls the rod member 35 d disposed in the valve unit 35 downward, and opens the valve unit 35. Further, the carriage driving unit 179 drives the carriage motor 2 to move the carriage 1 to the home position side and causes the cap unit 15 to cap the nozzle formation surface of the recording head 6.

  The sub tank position adjusting unit 182 reads out the head ID determined at the time of manufacture from the head ID storage unit 180 by the appropriate driving waveform maximum voltage VH of the recording head 6, and according to the head ID, the sub tank position adjustment unit 182 reads the head of the sub tank 7 from the sub tank adjustment value storage table 181. The adjustment value H is selected, and the actuator 17 is operated based on the head adjustment value H to adjust the position of the sub tank 7.

  FIG. 23 is a flowchart showing an example of a cleaning operation performed by using the functions of the valve units 35, 15V, and 37V. Hereinafter, the cleaning operation sequence will be described with reference to FIG. First, when the cleaning operation is started, the valve unit 15V corresponding to the recording head 6 to be cleaned is selected from the valve units 15V and 37V that have been previously closed to be opened.

  This is executed by the cleaning sequence control means 175 receiving a command from the host computer controlling the valve unit driving means 178, so that the rod member in the valve unit 15V is pulled downward by receiving the driving force of the actuator. (Step S11). Since the valve units 15V and 37V are closed in advance, the pressure reduction time during the cleaning operation can be shortened.

  Subsequently, the carriage 1 moves to the home position side (step S12), and the nozzle formation surface of the recording head 6 is capped by the cap unit 15 (step S13). Then, the valve unit 37V is selected to have a predetermined suction force and is opened. This is executed by the cleaning sequence control means 175 receiving a command from the host computer controlling the valve unit driving means 178 so that the rod member in the valve unit 37V is pulled downward by receiving the driving force of the actuator. (Step S14).

  Following this, the selected suction pump 37 is driven. This is executed by sending a control signal from the cleaning sequence control means 175 to the cleaning control means 173 and sending a command signal from the cleaning control means 173 to the pump drive means 174 (step S15). Then, the elapse of a predetermined time is awaited (step S16).

  Further, the valve unit 37V is selected so as to have a predetermined suction force and is opened, and the selected suction pump 37 is driven (steps S17 and S18). Then, the elapse of a predetermined time is awaited (step S19). As a result, bubbles present in the ink flow path with the thickened ink, in particular, bubbles remaining in the opening / closing control chamber 35h are discharged to the cap unit 15 side, and the ink discharged into the cap unit 15 passes through the suction pump 37. Then, it is discarded in the waste liquid tank 38.

  Next, the drive of the suction pump 37 is stopped (step S20), and the capping of the recording head 6 by the cap unit 15 is released (step S21). Then, the carriage 1 moves to the printing area side (step S22), the nozzle forming surface of the recording head 6 is wiped by the wiper unit 16, and paper dust or the like adhering to the nozzle forming surface of the recording head 6 is removed. .

  This is executed when the cleaning sequence control means 175 that has received a command from the host computer sends a control signal to the carriage drive means 179 (step S23). Further, the carriage 1 moves to a position where the recording head 6 and the cap member 15a face each other (step S24), the recording head 6 is flushed, and the cleaning process is finished.

  On the other hand, when performing choke cleaning, if it is determined in step S16 that a predetermined time has elapsed, the process branches to A, and the valve unit 35 to be choke cleaned is selected and closed. This is executed when the cleaning sequence control means 75 that receives a command from the host computer controls the valve unit driving means 178 and the valve unit 35 receives the urging force of the spring member 35g accommodated in the unit. (Step S25).

  Then, the selected suction pump 37 is driven to wait for a predetermined time (step S26). As a result, negative pressure is accumulated in the ink supply path from the sub tank 7 to the recording head 6. Then, the valve unit 35 is controlled to open. This is executed when the cleaning sequence control means 175 controls the valve unit driving means 178 and the rod member 35d in the valve unit 35 is pulled downward by receiving the driving force of the actuator (step S27). By opening the valve unit 35, an instantaneous ink flow is instantaneously generated in the ink supply path from the sub tank 7 to the recording head 6, and bubbles existing in the ink flow path together with the thickened ink, particularly opening and closing. Bubbles remaining in the control chamber 35h are discharged to the cap unit 15 side, and the choke cleaning process is finished.

  In the above-described embodiment, the printer has been described as an example. However, the present invention is not limited to this, and the present invention can also be applied to a recording apparatus having a recording medium conveyance guide unit, such as a facsimile apparatus or a copying apparatus.

  As described above, according to the ink jet recording apparatus and the adjustment method thereof according to the present invention, a large number of independent head units are arranged on the carriage. It is possible to replace a head unit with a predetermined characteristic or a head unit with a predetermined characteristic, which can improve the throughput for a large-sized recording medium and increase the recording accuracy. And can continue to maintain. Furthermore, since the water head difference between the ink surface in the sub-tank and the nozzle formation surface of the recording head can be adjusted, fine adjustment for each recording head can be performed, for example, when considering common drive waveforms in an ink jet recording apparatus. Even without this, the amount of ink ejected from the nozzles can be made uniform, and the recording accuracy can be further improved.

1 is a perspective view illustrating a configuration example of an ink jet printer according to an embodiment of an ink jet recording apparatus of the present invention. FIG. 2 is a partial cross-sectional side view of the ink jet printer shown in FIG. 1. FIG. 2 is a top view of a printing unit of the ink jet printer shown in FIG. 1. FIG. 2 is a plan view showing the periphery of a carriage of the ink jet printer shown in FIG. 1. It is the sectional view on the AA line of FIG. FIG. 6 is a diagram illustrating a relationship between a water head difference and an ink discharge weight for each recording head. It is a figure which shows the specific example of the characteristic shown in FIG. It is sectional drawing which shows the detail of the recording head of the ink jet type printer shown in FIG. It is a figure which shows typically the ink supply system mounted in the ink jet type printer shown in FIG. It is a figure which shows typically the cap unit and printing stage which were connected to the end of the suction tube of the ink supply system shown in FIG. FIG. 2 is a perspective view of a state in which a part of the sub tank of the ink jet printer of FIG. 1 is omitted and viewed from one surface direction. FIG. 2 is a perspective view of a state where a sub tank of the ink jet printer of FIG. 1 is viewed from one surface direction. FIG. 2 is a rear view of a state in which a sub tank of the ink jet printer of FIG. 1 is viewed from the back surface direction. FIG. 2 is an exploded perspective view illustrating a configuration of a float member housed in a sub tank of the ink jet printer of FIG. 1. FIG. 2 is an enlarged cross-sectional view illustrating a valve unit disposed in a part of a sub tank of the ink jet printer of FIG. 1. It is an expanded sectional view of the opening / closing control chamber part which showed the other valve unit of the ink jet type printer of FIG. It is sectional drawing which showed a part of structure of the main tank and cartridge holder of the ink jet type printer of FIG. FIG. 2 is a cross-sectional view illustrating a state where a main tank of the ink jet printer of FIG. 1 is mounted on a cartridge holder. It is the perspective view which showed a part of structure of the cartridge holder of the ink jet type printer of FIG. FIG. 2 is a partial cross-sectional view illustrating a state in which an on-off valve unit of the ink jet printer of FIG. 1 functions as a pressure adjustment valve. FIG. 2 is a partial cross-sectional view showing a state where an on-off valve unit of the ink jet printer of FIG. 1 is opened to the atmosphere. FIG. 2 is a block diagram illustrating a configuration of a control circuit mounted on the ink jet printer of FIG. 1. 13 is a flowchart showing a control routine of a cleaning operation performed by the control circuit shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Carriage, 6 ... Recording head, 7 (7a, 7b, 7c, 7d, 7e, 7f) ... Sub tank, 8 ... Cartridge holder, 9 (9a, 9b, 9c, 9d, 9e, 9f) ... Main tank, 10 ... head unit, 11 ... ink supply tube, 12 ... ink supply tube, 15 ... cap unit, 15V, 35V, 37V, 224V ... valve unit, 16 ... wiper unit, 17 ... actuator, 21 ... air pressure pump, 22 ... Pressure adjusting valve, 23 ... Pressure detector, 24 ... Ink pack, 25 ... Pressure chamber, 26 ... Ink supply valve, 31 ... Float member, 32 ... Permanent magnet, 33 (33a, 33b) ... Hall element, 37 ... Suction pump 37a ... Suction tube, 38 ... Waste liquid tank, 170 ... Print control means, 171 ... Head drive means, 172 ... Flash 173 ... Cleaning control means, 174 ... Pump drive means, 175 ... Cleaning sequence control means, 176 ... Cleaning command detection means, 177 ... Cleaning command switch, 178 ... Valve unit drive means, 179 ... Carriage drive means, 180 ... Head ID storage means, 181 ... Sub tank adjustment value storage table, 182 ... Sub tank position adjustment means, 200 ... Inkjet printer, 210 ... Paper feed section, 220 ... Printing section, 224 ... Print stage, 224a ... Small hole, 230 ... Paper discharge unit, 240 ... legs, 250 ... printer main body.

Claims (15)

A recording head for ejecting ink droplets to the recording medium, with receiving a supply of ink from the main tank, a plurality of head units having a sub tank for supplying the ink to said recording head,
The head unit is mounted on a carriage;
The ink jet recording apparatus according to claim 1, wherein the position of the sub tank is adjusted in a direction of lowering the water head with reference to the recording head having the highest driving voltage for driving the head. 2. The ink jet recording apparatus according to claim 1, wherein the position of the sub tank is adjusted during recording on the recording medium by the recording head. 3. The ink jet recording apparatus according to claim 1, wherein the position of the sub tank is adjusted at the stage of assembly to the carriage. Each head unit, the ink jet recording apparatus according to any one of claim 1 to 3, characterized in that it comprises the recording head and the sub tank of all color separation used in color printing. An ink jet recording apparatus according to any one of claim 1 to 4, characterized in that the common drive signal the each head unit is supplied. The main tank, an ink jet recording apparatus according to any one of claim 1 to 6, characterized in that are provided a plurality at different heights. Together to seal the nozzle formation surface of each recording head, any claim 1-6 in which the cap unit for sucking and discharging the ink from the recording head is characterized in that it is disposed in each of said recording head An ink jet recording apparatus according to claim 1. Wherein according to any one of claim 1 to 7, the first flow path opening and closing means for opening and closing control of the ink flow path around each recording head is characterized in that it is disposed in each of said ink flow path Inkjet recording device. 9. The ink jet recording apparatus according to claim 8 , wherein the first channel opening / closing means is disposed on the cap unit side. An ink jet recording apparatus according to any one of claims 10 to 9, characterized in that negative pressure generating means for the ink flow path to a negative pressure is arranged. 11. The ink jet according to claim 10 , wherein a plurality of the negative pressure generating means are provided, and a second flow path opening / closing means is provided for each of the ink flow paths on the negative pressure generating means side. Type recording device. Wherein by moving the array direction of the recording head, any claim 1 to 11 for the wiper unit for wiping a nozzle formation face of the recording head disposed on the movable area is characterized in that it is provided An ink jet recording apparatus according to claim 1. A recording head for ejecting ink droplets to the recording medium, with receiving a supply of ink from the main tank, a plurality of head units having a sub tank for supplying the ink to said recording head,
The head unit is an adjustment method of an ink jet recording apparatus mounted on a carriage ,
An adjustment method of an ink jet recording apparatus , wherein the position of the sub tank is adjusted in a direction of lowering a water head with reference to the recording head having the highest driving voltage for driving the head .   14. The method of adjusting an ink jet recording apparatus according to claim 13, wherein the position of the sub tank is adjusted during recording on the recording medium by the recording head. 15. The method of adjusting an ink jet recording apparatus according to claim 14 , wherein the position of the sub tank is adjusted in an assembly stage with respect to the carriage.

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