JP4979629B2 - Ink supply system, ink jet recording apparatus, and print head purging method - Google Patents

Description

  The present invention relates to an ink supply system provided with a valve mechanism for selectively opening a specific print head of a head unit, an ink jet recording apparatus, and a print head purging method.

  In a conventional ink jet recording apparatus, it is known that ink is ejected from a nozzle by pressurizing the ink for the purpose of maintenance such as prevention of drying of the nozzle of the print head and recovery from clogging.

  However, in a conventional ink jet recording apparatus, if ink is simply pressurized from an ink supply source, the ink is also supplied to a head that does not require maintenance. There is a problem that a desired ink pressure cannot be applied to a necessary head. This is particularly noticeable in the case of a line head type ink jet recording apparatus using a head unit composed of a large number of heads.

As a countermeasure, for example, Patent Document 1 discloses that a pressure difference is selectively generated with respect to at least one outlet of the ink manifold.
JP-T-2002-527273

  However, in Patent Document 1, the same number of solenoid valves as the number of heads, the drive source of each solenoid valve, and the drive source control mechanism are provided, and the head pressure is automatically controlled so that a desired pressure difference is generated in each head. It is carried out. For this reason, there exists a bad effect of causing the enlargement of a device, high cost, and complicated control.

  In view of the above facts, an object of the present invention is to provide an ink supply system, an ink jet recording apparatus, and a print head purging method that enable easy maintenance of a nozzle with a small mechanism. .

According to the first aspect of the present invention, a head unit having a plurality of print heads, an ink supply channel connected to an ink supply source and branching to each print head of the head unit, and each print head from the ink supply channel Ink supply means for supplying ink to the head unit, and a valve mechanism for selectively opening ink conduction in the ink supply flow path connected to a specific print head of the head unit, the valve mechanism comprising a drive source And a control mechanism having a shaft driven by the drive source, and the valve mechanism is provided in a plurality of stages from the upstream side to the downstream side of the ink supply flow path, and the most downstream side of the valve mechanism the said ink supply channel connected to the downstream, the print head is arranged, wherein the control mechanism controls the opening and closing of the valve mechanism by the position control of the shaft Characterized in that it is a structure.

  According to the first aspect of the present invention, maintenance such as clogging prevention can be performed by selectively pressurizing and purging a head unit having a plurality of print heads. And, compared with a system in which a valve having a drive source such as an electromagnetic valve is arranged upstream of each head, the number of drive sources can be greatly reduced and the control mechanism can be simplified. Can be reduced in size and price.

  In the first aspect of the present invention, the maintenance is not limited to sequentially opening all the print heads one by one, but the maintenance is performed by simultaneously opening a plurality of print heads (for example, two print heads). It is also possible.

  Further, the ink supply means may be a pressurizing pump that pressurizes the ink supply source, or may be a drawing pump that applies a negative pressure to the ink on the downstream side, or a circulation pump that circulates the ink. Is also possible.

In addition, it is possible to efficiently perform valve opening / closing control of a large number of print heads.

According to a second aspect of the present invention, an open / close valve that opens and closes an ink flow is disposed for each print head, and a single drive motor or rotary solenoid is provided as the drive source, and the shaft is the single drive motor. Alternatively, the rotary angle position is adjusted by a rotary solenoid, and the control mechanism is provided with a cam connected to the shaft and opening / closing the open / close valve according to the rotation phase angle of the shaft. To do.

According to the second aspect of the present invention, valve opening / closing control can be performed by providing a simple rotation mechanism as the control mechanism. Further, since the control mechanism can be configured not to move in the axial direction, a necessary space in the apparatus can be suppressed.

According to a third aspect of the present invention, an on-off valve for opening and closing the ink flow is disposed for each print head, and one linear actuator is provided as the driving source, and the shaft is positioned in the axial direction by the linear actuator. The control mechanism is provided with a cam portion that is formed on the shaft and that opens and closes the on-off valve according to an axial position of the shaft.

According to the third aspect of the present invention, valve opening / closing control can be performed by providing a simple linear mechanism as the control mechanism. Moreover, since it can be set as the structure which does not rotate a shaft, the space of the axial width direction of a shaft can be suppressed.

The invention according to claim 4 is characterized in that the on-off valve is a push-type valve that controls opening and closing by pressing a push button.

According to the fourth aspect of the present invention, valve opening / closing control can be reliably performed even with a weak pressing force. Moreover, since the reliability of the on-off valve can be easily increased, the valve life can be made relatively long.

The invention according to claim 5 is characterized in that the on-off valve is a tube pinch type valve that controls opening and closing by crushing a tube forming an ink flow path.

In the invention according to claim 5, the ink flow path when the valve is opened can be made large. Further, members other than the tube do not directly touch the ink, and the liquid resistance of the valve member does not become a problem.

According to a sixth aspect of the present invention, an ink recovery port through which recovery ink flows out is formed in each print head of the head unit, and an ink recovery port valve that simultaneously opens and closes the ink recovery port of each print head. A mechanism, an ink recovery channel communicating with the ink recovery port of each print head, ink supplied from the ink supply source, the ink supply channel, each print head of the head unit, and the ink recovery And an ink circulating means for circulating through the flow path.

In a system that circulates ink, it is generally necessary to prevent outflow of ink to the ink recovery port side when performing selective pressure purge. In the invention described in claim 6, this prevention can be achieved by simultaneously opening and closing the ink recovery port of each print head with one drive source, thereby realizing simplification of the apparatus and simplification of control. can do. Note that it is not necessary to selectively open and close the valve on the ink recovery port side, and it may be configured to be fully open or fully closed.

According to a seventh aspect of the present invention, the ink recovery port valve mechanism includes an ink recovery port drive source and an ink recovery port shaft driven by the ink recovery port drive source. The ink recovery port control mechanism is a mechanism for controlling valve opening / closing by position control of the ink recovery port shaft.

According to the seventh aspect of the present invention, the number of drive sources can be greatly reduced and the control mechanism can be simplified as compared with a system in which a valve having a drive source such as an electromagnetic valve is disposed upstream of each head. Therefore, it is possible to reduce the size and price of the apparatus.

An eighth aspect of the invention includes the ink supply system according to any one of the first to eighth aspects, wherein the plurality of print heads constituting the head unit are selectively pressurized to press the print head. It is characterized by performing maintenance.

In the invention according to the eighth aspect , in particular, in a line head type ink jet recording apparatus using a large number of heads, the apparatus can be reduced in size and cost.

  In addition, a configuration in which one or a smaller number of maintenance mechanisms than the number of line heads is provided for a plurality of line head units can reduce the size and cost of the apparatus. For example, even when four CMYK line head units are provided, one maintenance mechanism can be provided.

According to a tenth aspect of the present invention, there is provided a print head purging method using the ink supply system according to the first aspect, wherein the control mechanism is configured so that the number of print heads to be simultaneously opened is a predetermined number or less. The print heads are sequentially opened and purged.

In the invention according to the tenth aspect, since the print heads are sequentially opened and purged at a predetermined number or less (for example, one), it is possible to avoid that the number of print heads to be purged is too large to be purged sufficiently.

  According to the present invention, it is possible to provide an ink supply system, an ink jet recording apparatus, and a print head purging method that enable easy maintenance of a nozzle with a small mechanism.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. In the second and subsequent embodiments, the same components as those already described are denoted by the same reference numerals, and description thereof is omitted.

[First Embodiment]
First, the first embodiment will be described.

(Overall configuration of inkjet recording apparatus)
FIG. 1 is an overall configuration diagram of an ink jet recording apparatus showing an embodiment of an image forming apparatus according to the present invention. As shown in the figure, the inkjet recording apparatus 110 includes a plurality of full-line inkjets provided corresponding to black (K), cyan (C), magenta (M), and yellow (Y) inks. A printing unit 112 having recording heads (hereinafter referred to as line head units) 112K, 112C, 112M, 112Y, and an ink storage / loading unit for storing ink to be supplied to each of the line head units 112K, 112C, 112M, 112Y 114, a paper feeding unit 118 that supplies recording paper 116 as a recording medium, a decurling unit 120 that removes curling of the recording paper 116, and a nozzle surface (ink ejection surface) of the printing unit 112. The belt conveyance unit 122 that conveys the recording paper 116 while maintaining the flatness of the recording paper 116 and the printing by the printing unit 112 A print determination unit 124 which reads the result, and a paper output unit 126 for discharging the recorded recording paper (printed matter) to the outside. Note that “printing” as used in this specification includes printing of images in addition to printing of characters.

  The ink storage / loading unit 114 includes ink tanks that store inks of colors corresponding to the respective line head units 112K, 112C, 112M, and 112Y, and each tank is connected to the line head units 112K, 112C via a required pipe line. , 112M, 112Y. The ink storage / loading unit 114 includes notifying means for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 118, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  When a plurality of types of recording media (media) can be used, an information recording body such as a barcode or a wireless tag that records media type information is attached to a magazine, and information on the information recording body is read by a predetermined reader. It is preferable to automatically determine the type of recording medium to be used (media type) and to perform ink ejection control so as to realize appropriate ink ejection according to the media type.

  The recording paper 116 delivered from the paper supply unit 118 retains curl due to having been loaded in the magazine. In order to remove this curl, the decurling unit 120 applies heat to the recording paper 116 by the heating drum 130 in the direction opposite to the curl direction of the magazine. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  In the case of an apparatus configuration using roll paper, a cutter 128 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 128. Note that the cutter 128 is not necessary when cut paper is used.

  After the decurling process, the cut recording paper 116 is sent to the belt conveyance unit 122. The belt conveyance unit 122 is configured to have a structure in which an endless belt 133 is wound between the rollers 131 and 132.

  The belt 133 has a width that is greater than the width of the recording paper 116, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in the figure, a suction chamber 134 is provided at a position facing the nozzle surface of the print unit 112 and the sensor surface of the print detection unit 124 inside the belt 133 spanned between the rollers 131 and 132. The suction chamber 134 is sucked by the fan 135 to make a negative pressure so that the recording paper 116 is sucked and held on the belt 133. In place of the suction adsorption method, an electrostatic adsorption method may be adopted.

  The power of a motor (not shown) is transmitted to at least one of the rollers 131 and 132 around which the belt 133 is wound, whereby the belt 133 is driven in the clockwise direction in FIG. 1 and the recording paper held on the belt 133 116 is conveyed from left to right in FIG.

  Since ink adheres to the belt 133 when a borderless print or the like is printed, the belt cleaning unit 136 is provided at a predetermined position outside the belt 133 (an appropriate position other than the print region). Although details of the configuration of the belt cleaning unit 136 are not illustrated, for example, there are a method of niping a brush roll, a water absorption roll, etc., an air blow method of blowing clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip conveyance mechanism in place of the belt conveyance unit 122 is also conceivable, if the roller / nip conveyance is performed in the printing area, the image is likely to blur because the roller contacts the printing surface of the sheet immediately after printing. There's a problem. Therefore, as in this example, suction belt conveyance that does not bring the image surface into contact with each other in the print region is preferable.

  A heating fan 140 is provided on the upstream side of the printing unit 112 on the paper conveyance path formed by the belt conveyance unit 122. The heating fan 140 heats the recording paper 116 by blowing heated air onto the recording paper 116 before printing. Heating the recording paper 116 immediately before printing makes it easier for the ink to dry after landing.

  Each line head unit 112K, 112C, 112M, 112Y of the printing unit 112 has a length corresponding to the maximum paper width of the recording paper 116 targeted by the ink jet recording apparatus 110, and the nozzle surface has a maximum size recording. The paper 116 is a full line type in which a plurality of ink ejection nozzles are arranged over a length exceeding at least one side (full width of the drawable range) (see FIG. 2).

  The line head units 112K, 112C, 112M and 112Y are arranged in the order of black (K), cyan (C), magenta (M) and yellow (Y) from the upstream side along the feeding direction of the recording paper 116, respectively. The line head units 112K, 112C, 112M, and 112Y are fixedly installed so as to extend along a direction substantially orthogonal to the conveyance direction of the recording paper 116.

  A color image can be formed on the recording paper 116 by discharging different color inks from the line head units 112K, 112C, 112M, and 112Y while the recording paper 116 is being conveyed by the belt conveyance unit 122.

  As described above, according to the configuration in which the full-line type line head units 112K, 112C, 112M, and 112Y having nozzle rows that cover the entire width of the paper are provided for each color, the recording paper 116 and the paper 116 in the paper feeding direction (sub-scanning direction) An image can be recorded on the entire surface of the recording paper 116 by performing the operation of relatively moving the printing unit 112 once (that is, by one sub-scan). Thereby, it is possible to perform high-speed printing as compared with a shuttle type head in which the recording head reciprocates in a direction orthogonal to the paper transport direction, and productivity can be improved.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special color ink are used as necessary. May be added. For example, it is possible to add an ink jet head that discharges light ink such as light cyan and light magenta. Further, the arrangement order of the line head units for each color is not particularly limited.

  The print detection unit 124 shown in FIG. 1 includes an image sensor (line sensor or area sensor) for imaging the droplet ejection result of the printing unit 112, and nozzle clogging or the like from a droplet ejection image read by the image sensor. It functions as a means for checking ejection characteristics such as landing position errors.

  For the print detection unit 124 of this example, a CCD area sensor in which a plurality of light receiving elements (photoelectric conversion elements) are two-dimensionally arranged on the light receiving surface can be suitably used. The area sensor is assumed to have an imaging range in which the entire area of the ink ejection width (image recording width) by each of the line head units 112K, 112C, 112M, and 112Y can be imaged. A required imaging range may be realized by one area sensor, or a required imaging range may be secured by combining (connecting) a plurality of area sensors. Alternatively, a configuration in which the area sensor is supported by a moving mechanism (not shown) and the required imaging range is imaged by moving (scanning) the area sensor is also possible.

  Also, a line sensor can be used instead of the area sensor. In this case, it is preferable that the line sensor has a light receiving element array (photoelectric conversion element array) that is wider than at least the ink ejection width (image recording width) of each of the line head units 112K, 112C, 112M, and 112Y.

  As described above, the print detection unit 124 is a block including an image sensor, reads an image printed on the recording paper 116, performs necessary signal processing, and the like to perform a print status (presence / absence of ejection, landing position error, dot shape). , Optical density, etc.) and the detection result is provided to the print controller 180 and the system controller 172.

  A post-drying unit 142 is provided following the print detection unit 124. The post-drying unit 142 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by pressurizing the paper holes with pressure. There is an effect to.

  A heating / pressurizing unit 144 is provided following the post-drying unit 142. The heating / pressurizing unit 144 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 145 having a predetermined uneven surface shape while heating the image surface, and transfers the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 126. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 110 is provided with a sorting means (not shown) that switches the paper discharge path in order to select the prints of the main image and the prints of the test print and send them to the discharge units 126A and 126B. Yes.

  When the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by the cutter 148. Although not shown in the drawing, the paper output unit 126A for the target prints is provided with a sorter for collecting prints according to print orders.

  Next, the structure of the line head unit will be described. Since the structure of each line head unit 112K, 112C, 112M, and 112Y for each color is common, the line head unit will be denoted by reference numeral 150 as a representative of them.

  3 is a plan perspective view showing an example of the structure of the line head unit 150, and FIG. 4 is an enlarged view of a part thereof. 5 is a cross-sectional view (a cross-sectional view taken along line 33-33 in FIG. 4) showing a three-dimensional configuration of one droplet discharge element (an ink chamber unit corresponding to one nozzle 151).

  In order to increase the dot pitch printed on the recording paper 116, it is necessary to increase the nozzle pitch in the line head unit 150. As shown in FIGS. 3 and 4, the line head unit 150 of the present example includes a plurality of ink chamber units (droplet discharge units) including nozzles 151 serving as ink discharge ports and pressure chambers 152 corresponding to the respective nozzles 151. (Elements) 153 are arranged in a staggered matrix (two-dimensionally), and are thereby projected in a line along the longitudinal direction of the line head unit (direction perpendicular to the paper feed direction). High density of substantial nozzle interval (projection nozzle pitch) is achieved.

  Note that the form in which one or more nozzle rows are formed over a length corresponding to the entire width of the recording paper 116 in a direction substantially orthogonal to the feeding direction of the recording paper 116 is not limited to this example.

  The pressure chamber 152 provided corresponding to each nozzle 151 has a substantially square planar shape (see FIGS. 3 and 4), and the outlet to the nozzle 151 is provided at one of the diagonal corners. And an ink inlet (supply port) 154 for the supply ink. The shape of the pressure chamber 152 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, and an ellipse.

  As shown in FIG. 5, each pressure chamber 152 communicates with the common flow path 155 through the supply port 154. The common channel 155 communicates with an ink tank 202 (see FIGS. 8 and 9) serving as an ink supply source, and ink supplied from the ink tank 202 is distributed and supplied to each pressure chamber 152 via the common channel 155. The The ink jet recording apparatus 110 is provided with a pump 204 (see FIGS. 8 and 9) that pressurizes the ink in the ink tank 202.

  An actuator 158 having an individual electrode 157 is joined to a pressure plate (vibrating plate also serving as a common electrode) 156 constituting a part of the pressure chamber 152 (the top surface in FIG. 5). By applying a driving voltage between the individual electrode 157 and the common electrode, the actuator 158 is deformed to change the volume of the pressure chamber 152, and ink is ejected from the nozzle 151 due to the pressure change accompanying this. For the actuator 158, a piezoelectric element using a piezoelectric body such as lead zirconate titanate or barium titanate is preferably used. When the displacement of the actuator 158 returns to its original state after ink ejection, new ink is refilled into the pressure chamber 152 from the common flow path 155 through the supply port 154.

  By controlling the driving of the actuator 158 corresponding to each nozzle 151 according to the dot arrangement data generated from the image information, ink droplets can be ejected from the nozzle 151. As described with reference to FIG. 1, the recording paper 116 as a recording medium is transported in the sub-scanning direction at a constant speed, and the ink ejection timing of each nozzle 151 is controlled according to the transport speed, thereby forming the recording paper 116 on the recording paper 116. It is possible to record a desired image.

  As shown in FIG. 6, the ink chamber units 153 having the above-described structure are latticed in a fixed arrangement pattern along a row direction along the main scanning direction and an oblique column direction having a constant angle θ not orthogonal to the main scanning direction. The high-density nozzle head of this example is realized by arranging a large number in the shape.

  That is, with a structure in which a plurality of ink chamber units 153 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction, the pitch P of the nozzles projected so as to be aligned in the main scanning direction is d × cos θ. Thus, in the main scanning direction, each nozzle 151 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a high-density nozzle configuration in which 2400 nozzle rows are projected per inch (2400 nozzles / inch) so as to be aligned in the main scanning direction.

  By relatively moving the above-described full-line type line head unit and the paper, printing of one line (a line formed by a single line of dots or a line composed of a plurality of lines) is repeatedly performed. This is defined as sub-scanning.

  The direction indicated by one line (or the longitudinal direction of the belt-like region) recorded by the main scanning is referred to as the main scanning direction, and the direction in which the sub scanning is performed is referred to as the sub scanning direction. In other words, in the present embodiment, the conveyance direction of the recording paper 116 is the sub-scanning direction, and the direction orthogonal to it is the main scanning direction.

  In carrying out the present invention, the nozzle arrangement structure is not limited to the illustrated example. In this embodiment, a method of ejecting ink droplets by deformation of an actuator 158 typified by a piezo element (piezoelectric element) is adopted. However, the method of ejecting ink is not particularly limited in implementing the present invention. Instead of the piezo jet method, various methods such as a thermal jet method in which ink is heated by a heating element such as a heater to generate bubbles and ink droplets are ejected by the pressure can be applied.

  FIG. 7 is a block diagram showing a system configuration of the inkjet recording apparatus 110. As shown in the figure, the ink jet recording apparatus 110 is roughly configured to include a system control unit 200 and a print control unit 180.

  The system control unit 200 includes a communication interface 170, a system controller 172, an image memory 174, a ROM 175, a motor driver 176, a heater driver 178, and the like.

  The communication interface 170 is an interface unit with the host device 10 that is used for a user to give a printing instruction or the like to the inkjet recording apparatus 110. A serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied to the communication interface 170. In this part, a buffer memory (not shown) for speeding up communication may be mounted.

  Image data sent from the host device 10 is taken into the inkjet recording device 110 via the communication interface 170 and temporarily stored in the image memory 174. The image memory 174 is a storage unit that stores an image input via the communication interface 170, and data is read and written through the system controller 172. The image memory 174 is not limited to a memory composed of semiconductor elements, and a magnetic medium such as a hard disk may be used.

  The system controller 172 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 110 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. . That is, the system controller 172 controls the communication interface 170, the image memory 174, the motor driver 176, the heater driver 178, the print control unit 180, and the like, and performs communication control with the host device 10, the image memory 174, and the ROM 175. In addition to performing read / write control, a control signal for controlling the motor 188 and the heater 189 of the transport system is generated. In addition to the control signal, image information stored in the image memory 174 is transmitted to the print control unit 180. Further, the system controller 172 can generate landing position error data, dot shape data, and the like from the read data read from the print detection unit 124.

  The ROM 175 stores programs executed by the CPU of the system controller 172 and various data necessary for control. The ROM 175 may be a non-rewritable storage unit. However, when various types of data are updated as necessary, it is preferable to use a rewritable storage unit such as an EEPROM.

  The image memory 174 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 176 is a driver (driving circuit) that drives the conveyance motor 188 in accordance with an instruction from the system controller 172. The heater driver 178 is a driver that drives the heater 189 such as the post-drying unit 142 in accordance with an instruction from the system controller 172.

  The print control unit 180 functions as a signal processing unit that performs various processes such as processing and correction for generating a discharge control signal from the image information transmitted from the system control unit 200 according to the control of the system controller 172. The ejection driving of the line head unit 150 is controlled based on the generated ink ejection data.

(Maintenance mechanism and associated structure)
Hereinafter, a maintenance mechanism provided in the ink jet recording apparatus 110 and a configuration associated therewith will be described. Since the basic configuration does not change regardless of the number of print heads constituting each line head unit, each line head unit is composed of four head units for convenience of explanation. The following description will be made assuming that four print heads are provided.

  In each of the line head units 112K, 112C, 112M, and 112Y, the head units 206A to 206A-D are arranged in a line as shown in FIG. The ink jet recording apparatus 110 includes a maintenance mechanism 210 for each line head unit of each color of YMCK. Since the configuration and operation of the maintenance mechanism 210 are the same for each color of YMCK, the maintenance mechanism 210 for one color (for example, black) will be described in detail below.

  The maintenance mechanism 210 is provided to selectively pressurize and purge the print heads 208 constituting the head units 206A to 206D to prevent clogging. The maintenance mechanism 210 has an ink supply channel 212 that communicates with one ink tank 202 and branches to each print head of each head unit 206A-D to distribute ink.

  The ink supply channel 212 includes a first-stage supply channel 216 including branch pipes 214A to 214D (see FIG. 9) that are branched into four. On-off valves 218A to 218D are connected to the branch pipes 214A to 214D, respectively.

  Further, the ink supply channel 212 includes second-stage supply channels 226A to 226D that communicate with the downstream sides of the on-off valves 218A to 218D, respectively. The second stage supply channel 226A has branch pipes 224A1 to A4 that are branched into four. The second stage supply flow path 226B also includes branch pipes 224B1 to B4 that branch into four, the second stage supply flow path 226C also includes branch pipes 224C1 to C4 that branch into four, and the second stage supply flow path 226D as well. It has branch pipes 224D1 to D4 that branch into four. On-off valves 228A1 to A4 are connected to the branch pipes 224A1 to A4, respectively. Similarly, on-off valves 228B1-B4 are connected to branch pipes 224B1-B4, on-off valves 228C1-C4 are connected to branch pipes 224C1-C4, respectively, and on-off valves 228D1-D4 are connected to branch pipes 224D1-D4. Each is connected.

  Print heads 208A1 to A4 are connected to the downstream sides of the on-off valves 228A1 to A4, respectively, and print heads 208B1 to B4 are connected to the downstream sides of the on-off valves 228B1 to B4, respectively. Further, print heads 208C1 to C4 are connected to the downstream side of the on-off valves 228C1 to C4, respectively, and print heads 208D1 to D4 are connected to the downstream side of the on-off valves 228D1 to D4, respectively.

  The maintenance mechanism 210 includes a first stage valve mechanism 230 that opens and closes the on-off valves 218A to 218D, and a second stage valve mechanism that opens and closes the on-off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4. 240.

  As shown in FIGS. 9 and 10, the first stage valve mechanism 230 includes a first drive source (for example, a drive motor) 232 and a first shaft 234 that is rotationally driven by the first drive source 232. . Further, the first stage valve mechanism 230 includes cams 236A to 236D that are connected to the first shaft 234 and open and close the on-off valves 218A to 218D, respectively. The rotation phase angle of the first shaft 234 by the first drive source 232 is controlled by the system controller 172.

  The second stage valve mechanism 240 includes a second drive source (for example, a drive motor) 242 and a second shaft 244 that is rotationally driven by the second drive source 242. Further, the second stage valve mechanism 240 is connected to the second shaft 244 to open and close the on-off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4, respectively, cams 246A1 to A4, B1 to B4, and C1. To C4 and D1 to D4. The rotational phase angle of the second shaft 244 by the second drive source 242 is also controlled by the system controller 172.

  As shown in FIGS. 10 and 11, each of the on-off valves 218 </ b> A to 218 </ b> D has a push button-like valve body 237 that opens and closes the ink flow path, and a compression coil spring 238 that biases the valve body 237 (see FIG. 11). And. With this configuration, the valve body 237 is pressed by the cams 236A to 236D and the valve body 237 is closed, and the contact position of the cams 236A to D with the valve body 237 is retracted, whereby the valve body 237 is pushed out by the compression coil spring 238. The valve is open. Note that the compression coil spring 238 may be another urging member such as a plate spring or a wire spring.

  The cam 236A has recesses 239M and 239P formed by steps. When the recesses 239M and 239P are in contact with the valve body 237, the valve body 237 is pushed out and the on-off valve 218A is opened. The formation position of the recess 239P on the cam 236A is set to a position of θA = 72 ° in the direction opposite to the rotation direction of the first shaft 234 from the recess 239M.

  Recesses 239M and 239P are also formed in the cam 236B. The formation position of the recess 239P on the cam 236B is set at θA = 2 × 72 °, that is, 144 ° in the direction opposite to the rotation direction of the first shaft 234 from the recess 239M. Recesses 239M and 239P are also formed in the cam 236C. The formation position of the recess 239P on the cam 236C is set at θA = 3 × 72 °, that is, 216 ° in the direction opposite to the rotation direction of the first shaft 234 from the recess 239M. Recesses 239M and 239P are also formed in the cam 236D. The position where the recess 239P is formed on the cam 236D is set to θA = 4 × 72 °, that is, 288 ° in the direction opposite to the rotation direction of the first shaft 234 from the recess 239M.

  The cams 236A to 236D are connected to the first shaft 234 so that the recesses 239M have the same rotational phase angle, that is, the recesses 239P of the cams are positioned on the same straight line. Therefore, it is possible to open all the on-off valves 218A-D by simultaneously bringing the recesses 239M into contact with the valve bodies 237 of the on-off valves 218A-D (see FIG. 11B). By arranging the recess 239P of each cam in this way, when the recess 239P contacts the valve body 237, it contacts one of the valve bodies 237 of the on-off valves 218A to 218D. The concave portion 239 </ b> P does not contact the valve body 237 at the same time.

  The on-off valves 228A1, B1, C1, and D1 are all connected to the second shaft 244 with the same configuration as the on-off valve 218A and the same rotational phase angle. The on-off valves 228A2, B2, C2, and D2 are all connected to the second shaft 244 with the same configuration as the on-off valve 218B and the same rotational phase angle. The on-off valves 228A3, B3, C3, and D3 are all connected to the second shaft 244 with the same configuration as the on-off valve 218C and the same rotational phase angle. The on-off valves 228A4, B4, C4, and D4 are all connected to the second shaft 244 with the same configuration as the on-off valve 218D and the same rotational phase angle. Accordingly, the recesses 239M are simultaneously brought into contact with the valve bodies 237 of the on-off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4, and the on / off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4. Can be opened. When the recess 239P contacts the valve body 237 by arranging the recess 239P of each cam 246 in this manner, (1) the on-off valve 228A1, B1, C1, D1, (2) the on-off valve 228A2, B2, C2, D2, (3) Open / close valves 228A3, B3, C3, D3, (4) Open / close valves 228A4, B4, C4, D4 All are open and all other open / close valve groups are closed. And two or more on-off valve groups of (1)-(4) do not open simultaneously.

(Function, effect)
Hereinafter, the operation and effect of the present embodiment will be described. In order to selectively open and maintain the print heads in the inkjet recording apparatus 110, the print heads to be opened are sequentially opened one by one to discharge ink.

  For example, as shown in FIGS. 8 and 9, the first drive source 232 adjusts the rotation angle of the first shaft 234, opens the on-off valve 218B, and closes the on-off valves 218A, 218C, 218D. As a result, the on-off valves 228A1-4, C1-C4, and D1-D4 are all closed. In FIG. 9, the white open / close valve is open and the black open / close valve is closed.

  Further, the rotation angle of the second shaft 244 is adjusted by the second drive source 242 to open the on-off valve 228B2 and to close the on-off valves 228B1, 228B3, 228B4. As a result, only the on-off valve 228B2 is selectively opened, that is, only the print head 208B2 is selectively opened.

  In this state, the ink in the ink supply channel pressurized by the pump 204 is ejected only from the print head 208B2. Accordingly, the pressure applied to the print head 208B2 is significantly greater than when ink is ejected simultaneously from all the print heads or from a plurality of print heads.

  The rotation phase angle of the first shaft 234 by the first drive source 232 and the rotation phase angle of the second shaft 244 by the second drive source 242 are sequentially changed so that this is sequentially performed for each print head (every 72 °). Change).

  Accordingly, maintenance such as clogging prevention can be performed by selectively pressurizing and purging each print head. In addition, the number of drive sources can be greatly reduced and the control mechanism can be simplified as compared with a system in which a valve having a drive source such as an electromagnetic valve is disposed upstream of each head, and the control mechanism can be simplified. The recording apparatus 110 can be reduced in size and price.

  Further, a valve mechanism (a first stage valve mechanism 230 and a second stage valve mechanism 240) is provided in two stages from the upstream side to the downstream side. Thereby, it can be set as the structure which performs the valve opening / closing control of many print heads efficiently.

  Further, by adjusting the rotational phase angles of the first shaft 234 and the second shaft 244 by a drive source (drive motor), the rotational phase angles of the cams respectively connected to the respective shafts are adjusted to control each on-off valve. It is carried out. Therefore, a simple rotation mechanism is provided as an opening / closing control mechanism for the opening / closing valve. Further, since the first shaft 234 and the second shaft 244 do not move in the axial direction, it is not necessary to provide a movement space in the axial direction of the first shaft 234 and the second shaft 244 in the apparatus, and it is easy to reduce the size.

  The on-off valves 218A to 218D, on-off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4 are push-type valves that control opening and closing by pushing a push button-like valve body 237. Thereby, the opening / closing control of the valve can be reliably performed even with a weak pressing force. Further, since the reliability of the valve can be easily increased, the valve life can be made relatively long.

[Second Embodiment]
Next, a second embodiment will be described. As shown in FIG. 12, in the present embodiment, a first stage valve mechanism 330 is provided in place of the first stage valve mechanism 230, as compared with the first embodiment.

  The first stage valve device 330 is provided with one linear actuator 332 as a drive source, and a first shaft 334 is provided instead of the first shaft 234.

  The first shaft 334 is moved in the axial direction by a linear actuator 332. The first shaft 334 is formed with concave and convex cam portions 336A to 336D that respectively open and close the on-off valves 218A to 218D.

  According to this embodiment, the opening / closing control of the opening / closing valves 218A to 218D can be performed by providing a simple linear mechanism as the control mechanism. Further, since the first shaft 334 does not rotate, the space in the axial width direction can be suppressed.

  Instead of the second shaft 244 and the second drive source 242, a second shaft that opens and closes the on-off valves 228A1 to A4, B1 to B4, C1 to C4, and D1 to D4, and the second shaft in the axial direction. If the linear actuator to be moved is provided, the same effect can be further obtained.

[Third Embodiment]
Next, a third embodiment will be described. As shown in FIG. 13, in this embodiment, compared with 1st Embodiment, it replaces with on-off valve 228A1-4, B1-B4, C1-C4, D1-D4, and on-off valve 428A1-A4, B1-B4, C1. To C4 and D1 to D4 are provided. In FIG. 13, the on / off valve 428 is simply denoted by the reference numeral 428 to indicate one on / off valve among the on / off valves 428A1 to B4, B1 to B4, C1 to C4, and D1 to D4.

  The on-off valve 428 is a tube pinch type valve that controls opening and closing by crushing a tube 429 forming an ink flow path.

  According to this embodiment, it is possible to make a large ink flow path when the valve is opened. Further, members other than the tube 429 do not directly touch the ink, and the liquid resistance of the valve member does not become a problem.

  If the on-off valves 218A to 218D are similarly tube pinch type valves, the same effect can be further obtained.

[Fourth Embodiment]
Next, a fourth embodiment will be described. In the inkjet recording apparatus 510 according to the present embodiment, as shown in FIG. 14, instead of the print heads 208A1 to A4, B1 to B4, and C1 to C4D1 to D4, ink for collection is used as compared with the first embodiment. Print heads 508A1 to 508, B1 to B4, C1 to C4, and D1 to D4, in which an outflow ink recovery port 511 is further formed, are provided.

  The inkjet recording apparatus 510 includes an ink recovery port valve mechanism 550 that simultaneously opens and closes the ink recovery ports 511 of the print heads, and an ink recovery flow channel that integrates the ink recovery ports 511 of the print heads into one flow channel. 552 and the ink supplied from the ink tank 502 are circulated through the ink supply channel 212, the print heads 508A1 to 508, B1 to B4, C1 to C4, D1 to D4, and the ink recovery channel 552. An ink circulation mechanism 530 is provided.

  The ink recovery channel 552 communicates with the ink recovery port branch pipe 554 connected to each of the print heads 508A1 to 508, B1 to B4, C1 to C4, and D1 to D4, and the ink recovery port branch pipe 554. Thus, an integrated flow path 556 that forms one flow path is formed. Each ink recovery port branch pipe 554 is provided with an ink recovery port opening / closing valve 558.

  The ink recovery port valve mechanism 550 includes an ink recovery port drive source 562 and an ink recovery port shaft 564 that is rotationally driven by the ink recovery port drive source 562. The ink recovery port shaft 564 is provided with a cam 566 (for example, see FIG. 15) for opening and closing each ink recovery port opening / closing valve 558. All the cams 566 have the same shape, and the cams 566 have the same rotational phase angle. Accordingly, the position of the ink recovery port shaft 564 is controlled so that the ink recovery port shaft 564 can be switched between the closed state and the open state.

  In a system that circulates ink, it is generally necessary to prevent ink from flowing out to the ink recovery port side when performing selective pressure purging. In this embodiment, this prevention is achieved by using one drive source. Thus, the ink recovery ports 511 can be opened and closed simultaneously. Therefore, simplification of the apparatus and simplification of control can be realized.

  As shown in FIG. 15, a composite on-off valve 578 in which an on-off valve 228 and an ink recovery port on-off valve 558 are formed as one member may be provided for each print head.

  In addition, the ink tank 202 and the ink tank 502 may be configured as one ink tank.

[Fifth Embodiment]
Next, a fifth embodiment will be described. In the present embodiment, line head units 612K, 612C, 612M, and 612Y similar to the line head units 112K, 112C, 112M, and 112Y are provided. The line head units 612K, 612C, 612M, and 612Y are different from the line head units 112K, 112C, 112M, and 112Y in that they are configured to move individually in the ink jet recording apparatus. The line head unit 112K is provided with an ink supply port opening / closing valve that opens and closes the ink supply port of each print head and an ink recovery port opening / closing valve that opens and closes the ink recovery port of each print head. The same applies to the line head units 112C, 112M, and 112Y.

  As shown in FIG. 16, one maintenance station 620 arranged at a position different from the line head units 612K, 612C, 612M, 612Y is provided. The maintenance station 620 is configured such that the line head units 612K, 612C, 612M, and 612Y can be carried in and out as a single unit.

  The maintenance station 620 includes an ink supply opening / closing control mechanism 630 that selectively opens the ink supply port of a specific print head of the line head unit that has been loaded on the same principle as described in the first embodiment. Is provided.

  Further, the maintenance station 620 is provided with an ink collection opening / closing control mechanism 640 that opens and closes the ink collection port of each print head of the line head unit that is carried in on the same principle as described in the fourth embodiment. It has been.

  In the present embodiment, in particular, when a plurality of line heads are provided so that printing can be performed in multiple colors, the line head unit is provided by providing an opening / closing control mechanism for performing valve opening / closing control in the maintenance station without providing the line head unit. Can be reduced in size and weight.

  Even if four line head units 612K, 612C, 612M, and 612Y are provided in the ink jet recording apparatus, one open / close control mechanism 630 for supplying ink to the maintenance station 620 and one open / close control for collecting ink are provided. By providing the mechanism 640, the maintenance of the line head units 612K, 612C, 612M, and 612Y can be shared. Accordingly, it is possible to reduce the size and cost of the ink jet recording apparatus.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

1 is a side view showing an overall configuration of an ink jet recording apparatus according to a first embodiment. It is a top view which shows the structure of the printing part of the inkjet recording device which concerns on 1st Embodiment, and its periphery. 2 is a perspective plan view showing a structural example of a head of the ink jet recording apparatus according to the first embodiment. FIG. FIG. 4 is an enlarged view of an ink chamber unit in FIG. 3. It is sectional drawing in the 33-33 cutting line of FIG. FIG. 2 is a schematic diagram illustrating an example of a nozzle arrangement of a head of the ink jet recording apparatus according to the first embodiment. It is the schematic which shows an example of the electrical constitution of the inkjet recording device which concerns on 1st Embodiment. It is a block diagram of the maintenance mechanism of the inkjet recording device which concerns on 1st Embodiment. It is a typical block diagram which shows performing valve opening / closing control with the maintenance mechanism of the inkjet recording device which concerns on 1st Embodiment. It is a perspective view explaining opening and closing of a valve with the shaft and cam provided in the maintenance mechanism of the ink-jet recording device concerning a 1st embodiment. 11A and 11B show a state in which only one on-off valve is opened and all on-off valves are opened by four cams having different rotational phase angles in the first embodiment. It is side surface sectional drawing which shows a state. It is explanatory drawing explaining the 1st step valve mechanism provided in the maintenance mechanism of the inkjet recording device which concerns on 2nd Embodiment. FIGS. 13A and 13B are side cross-sectional views showing a state where the on-off valve is opened and a state where the on-off valve is closed in the third embodiment, respectively. It is a block diagram of the maintenance mechanism of the inkjet recording device which concerns on 4th Embodiment. FIG. 10 is a side cross-sectional view illustrating that an ink recovery port of a print head can be opened and closed in a fourth embodiment. In 5th Embodiment, it is explanatory drawing explaining that each line head unit is set as the structure carried in and carried out by a maintenance mechanism.

Explanation of symbols

110 Inkjet recording device 112K Line head unit 112C Line head unit 112M Line head unit 112Y Line head unit 202 Ink tank (ink supply source)
204 Pump (ink supply means)
206A to D Head units 208A1 to A4 Print heads 208B1 to B4 Print heads 208C1 to C4 Print heads 208D1 to D4 Print head 210 Maintenance mechanism 212 Ink supply flow paths 218A to D Open / close valves 228A1 to A4 Open / close valves 228B1 to B4 Open / close valves 228C1 C4 On-off valve 228D1-D4 On-off valve 230 First stage valve mechanism (valve mechanism)
232 1st drive source 234 1st shaft 236A-D Cam 237 Valve body (push button)
240 Second stage valve mechanism (valve mechanism)
242 Second drive source 244 Second shaft 246A1-A4 Cam 246B1-B4 Cam 246C1-C4 Cam 246D1-D4 Cam 330 First stage valve mechanism (valve mechanism)
332 Linear actuator 334 First shaft 336A-D Cam portion 428A1-A4 On-off valve 428B1-B4 On-off valve 428C1-C4 On-off valve 428D1-D4 On-off valve 429 Tube 508A1-A4 Print head 508B1-B4 Print head 508C1-C4 Print head 508D1 D4 Print head 510 Inkjet recording device 511 Ink collection port 530 Ink circulation mechanism 550 Ink collection port valve mechanism 552 Ink collection channel 558 Ink collection port open / close valve 562 Ink collection port drive source 564 Ink collection port shaft 612K line Head unit 612C Line head unit 612M Line head unit 612Y Line head unit 620 Maintenance station 630 Opening / closing control mechanism

Claims (9)

A head unit having a plurality of print heads;
An ink supply channel connected to an ink supply source and branched to each print head of the head unit;
Ink supply means for supplying ink from the ink supply channel to each print head;
A valve mechanism for selectively opening ink conduction in the ink supply flow path connected to a specific print head of the head unit,
The valve mechanism includes a drive source,
A control mechanism having a shaft driven by the drive source,
The valve mechanism is provided in a plurality of stages from the upstream side to the downstream side of the ink supply flow path, and the print head is disposed in each of the ink supply flow paths connected downstream of the valve mechanism on the most downstream side. ,
The ink supply system according to claim 1, wherein the control mechanism is a mechanism for controlling opening and closing of the valve mechanism by position control of the shaft. The on- off valve for opening and closing the ink flow is arranged for each print head;
One drive motor or rotary solenoid is provided as the drive source,
The shaft is provided such that a rotational angle position is adjusted by the one drive motor or a rotary solenoid,
2. The ink supply system according to claim 1, wherein the control mechanism includes a cam connected to the shaft and configured to open and close the on-off valve according to a rotation phase angle of the shaft. An open / close valve that opens and closes the ink flow is arranged for each print head.
One linear actuator is provided as the drive source,
The shaft is provided such that an axial position thereof is adjusted by the linear actuator ,
The ink supply system according to claim 1, wherein the control mechanism includes a cam portion that is formed on the shaft and that opens and closes the on-off valve according to an axial position of the shaft. The ink supply system according to any one of claims 1 to 3, wherein the on-off valve is a push-type valve that controls opening and closing by pressing a push button . The ink supply system according to any one of claims 1 to 3, wherein the on-off valve is a tube pinch type valve that controls opening and closing by crushing a tube forming an ink flow path . Each print head of the head unit is formed with an ink recovery port through which recovery ink flows.
An ink recovery port valve mechanism for simultaneously opening and closing the ink recovery port of each print head;
An ink recovery flow path communicating with the ink recovery port of each print head;
An ink circulation means for circulating the ink supplied from the ink supply source via the ink supply flow path, each print head of the head unit, and the ink recovery flow path;
The ink supply system according to claim 1, wherein the ink supply system is provided. The ink recovery port valve mechanism includes an ink recovery port drive source;
An ink recovery port control mechanism having an ink recovery port shaft driven by the ink recovery port drive source;
Have
The ink supply system according to claim 6, wherein the ink recovery port control mechanism is configured to control valve opening / closing by position control of the ink recovery port shaft . It has an ink supply system given in any 1 paragraph among Claims 1-7,
An ink jet recording apparatus that performs maintenance of a print head by selectively pressurizing a plurality of print heads constituting the head unit . A method for purging a print head using the ink supply system according to claim 1,
A method for purging a print head, wherein the control mechanism is configured such that the number of print heads to be simultaneously opened is equal to or less than a predetermined number, and the print heads are sequentially opened and purged .

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