JP2019217644A - Inkjet recording device and recording head suction method - Google Patents

Abstract

To provide a discharge performance recovery device that can secure discharge performance without wasting ink by appropriately executing processing for recovering discharge performance of each recording head, and an inkjet recording device.SOLUTION: In a printer equipped with a plurality of recording heads 131 which discharge retained ink I through discharge ports to form images and a suction pump 141 connected through a pressure adjustment chamber 144s to a closed space 133s formed by attaching caps to discharge port forming surfaces of the recording heads, a control part, when suctioning ink in the discharge ports by setting the closed space to negative pressure to recover discharge performance, makes amounts of ink in an ink tank 131T of the recording head that performs the recovery processing smaller than volumes in the ink tank of the recording head that does not perform the recovery processing.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet printing apparatus for realizing a process for restoring ink ejection performance for each print head and a method for sucking the print head.

  2. Description of the Related Art Ink jet recording apparatuses are frequently used in printers that form images on recording media such as roll paper and cut paper. This ink jet recording apparatus employs a recording method of forming an image on a recording medium by discharging ink as fine ink droplets from fine discharge ports of a recording head. For this reason, in the ink jet recording apparatus, the viscosity increases as the ink waiting in the discharge port of the recording head dries, so-called thickening, and the quality of the ink deteriorates. Then, the ejection quality of the ink droplets deteriorates, and the ejection openings are more likely to be clogged.

  For this reason, the ink jet recording apparatus is provided with a mechanism for attaching and detaching a cap for covering the surface on which the ejection openings of the recording head are formed. Further, in this ink jet recording apparatus, a mechanism for performing a recovery process such as applying a negative pressure for sucking a fixed amount of ink from the discharge port in order to eliminate a thickened state or clogging of the ink in the discharge port of the recording head. Is provided. Such an ink jet recording apparatus is disclosed, for example, in Patent Document 1.

  In addition, by equalizing the negative pressure applied to each of a plurality of recording heads with a common pressure chamber interposed, ink can be sucked from all the ejection openings without excess and deficiency, and the ejection performance of each recording head can be properly adjusted. Patent Document 2 discloses an ink jet recording apparatus that realizes recovery.

JP 2001-347689 A JP 2012-35424 A

  However, in such an ejection performance recovery apparatus mounted on an ink jet recording apparatus, since the ejection ports of all the recording heads are uniformly targeted for the recovery process, the ejection performance does not cause a problem such as thickening. Ink is also sucked from the outlet. For this reason, the recovery process of the ejection performance has led to waste of ink. In this recovery processing, the more ink the viscosity increases, the more difficult it is to suck the ink from the ejection port, and the more the ink is sucked from the ejection port that does not cause a problem.

  Therefore, the present invention restricts ink suction from the ejection port in a recording head that does not require a recovery process of the ink ejection performance, thereby suppressing waste of ink, and effectively improving the ink ejection performance in a recording head that requires the recovery process. It is an object of the present invention to provide an ink jet recording apparatus and a recording head suction method for restoring the pressure to a minimum.

  According to one aspect of the invention of an ink jet recording apparatus that solves the above-described problem, a plurality of recording heads capable of storing ink therein and discharging ink from a discharge port to form an image on a recording medium; A negative pressure generating means for forming a closed space between the discharge port forming surface on which the outlet is formed and making the closed space a negative pressure, and the negative pressure generating means functioning to make the closed space a negative pressure Recovery means for sucking ink from the ejection openings to restore ink ejection performance, ink amount adjustment means for adjusting the amount of ink stored in the recording head, and the suctioning of the plurality of recording heads. And a control unit for performing the suction in a state in which the amount of stored ink in the print head to be performed is smaller than the stored amount of the print head in which the suction is not performed.

  One embodiment of the invention of a recording head suction method that solves the above-described problem is that a plurality of recording heads that can store ink therein and perform recording by discharging ink from discharge ports formed on a discharge port forming surface are provided. A suction method of performing suction, wherein, among the plurality of print heads, an ink amount adjustment step of reducing the amount of ink stored in the print head performing suction, to be smaller than the storage amount of the print head not performing suction. Forming a closed space for closing the discharge port forming surfaces of the plurality of recording heads, and suctioning ink in the discharge ports by setting the inside of the closed space to negative pressure. I have.

  As described above, according to one aspect of the present invention, in a print head that does not require the recovery process of the ink ejection performance, the ink suction from the ejection port is limited to suppress the waste of ink, and in a print head that requires the recovery process, The ink ejection performance can be effectively recovered.

FIG. 1 is a conceptual configuration diagram showing a printer as an example of an ink jet recording apparatus equipped with an ejection performance recovery device according to an embodiment of the present invention. FIG. 2 is a partial longitudinal configuration diagram showing a main configuration for recovering the ejection performance of the recording head. FIG. 3 is an ink flow path diagram for realizing the recovery of the ejection performance of the recording head and the replenishment of the ink. FIG. 4 is a related block diagram illustrating a control process of the image recording system including the printer. FIG. 5 is a flowchart illustrating a control process for recovering the ejection performance of the print head.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 to 5 are views for explaining a printer which is an example of an ink jet recording apparatus equipped with an ejection performance recovery apparatus according to an embodiment of the present invention. FIG. 1 is an overall configuration of an image recording system including the printer. It is a conceptual block diagram explaining.

  In FIG. 1, a printer 100 is a recording apparatus that forms and prints an image by an inkjet recording method using a label sheet P on which a plurality of labels are temporarily attached and wound in a roll shape as a recording medium. In the printer 100, for example, a terminal device E of a PC (Personal Computer) is connected as a host device, and is incorporated as a part of an image recording system. The printer 100 forms an image by discharging each color ink from the discharge port 132 of the recording head 131 for each label of the label paper P at the image forming position based on the image data sent from the PC terminal device E.

  Here, in the present embodiment, as an example of the recording medium, a description will be given using a roll of label paper (roll paper) P, but the present invention is not limited to this, and for example, cut paper that has been cut to a predetermined size, etc. Other forms may be used. It goes without saying that the present invention may be applied to a printer that forms an image on a recording medium other than paper.

  The printer 100 records and forms the image data received from the PC terminal device E on the conveyed label sheet P by controlling each unit of the apparatus such as the sheet unit 110 and the recording unit 130 by the control unit 150.

  The paper unit 110 pulls out the label paper P wound around the paper shaft 112 by pulling in the direction of arrow A in the conveying direction while rotating the paper feed roller pair 111 to feed the label paper P to the image forming position by the recording unit 130. Paper. The paper unit 110 conveys the label paper P pulled out from the paper shaft 112 such that it passes through the image forming position of the recording unit 130 by rotating while the conveyance belt 113 is sandwiched between the driven rollers 118a and 118b. Take it out of the device. The transport belt 113 is wound around rollers 114a and 114b before and after the image forming position, a tension pulley 116 for applying a tension for preventing loosening, and a drive shaft 117a of a motor 117 driven and controlled by the control unit 150, so that the transport belt 113 is rotated forward and backward. It is driven to rotate. The label paper P is detected by the various sensors (not shown) connected to the control unit 150 for the label position and the transport speed, and is appropriately stopped by the paper unit 110, and is subjected to the image forming process by the recording unit 130. After that, it is carried out of the device.

  The recording unit 130 is configured to include a plurality of recording heads 131 for each color employing an inkjet recording method. The recording head 131 discharges each color ink I in the ink tank 131T (see FIG. 2) from the discharge port (nozzle) 132 of the nozzle forming surface 131a facing the label paper P on the lower surface side as granular ink droplets. A recording operation for forming an image on the label paper P is performed. In the recording head 131, a plurality of ink ejection ports 132 are arranged so that a nozzle width is set in a paper width direction orthogonal to the transport direction A of the label paper P. That is, the recording head 131 is formed in a so-called elongate form of a so-called full line head that covers the entire width of the label paper P as an image forming area.

  Here, the recording head 131 instantaneously generates bubbles by energizing an electrothermal conversion element (heater) installed in an ink flow path communicating with the ejection port 132, so that ink droplets are discharged from the ejection port 132. In other words, a so-called thermal method for discharging the ink is adopted. The recording head 131 is not limited to the thermal type. For example, a so-called piezo type in which a piezoelectric element (piezo element) that instantaneously changes the capacity of an ink flow path is installed and ink droplets are ejected from an ejection port 132 thereof. It is needless to say that may be adopted.

  The recording unit 130 includes separate recording heads 131Y, 131M, 131C, and 131K for each color ink I of yellow (Y), magenta (M), cyan (C), and black (K). In the recording unit 130, the recording heads 131K, 131C, 131M, and 131Y are sequentially arranged in parallel so that images are formed in an order suitable for image formation from upstream to downstream in the transport direction A of the label paper P. I have. Accordingly, the recording head 131 ejects the black (K), cyan (C), magenta (M), and yellow (Y) color inks I in accordance with the transport of the label paper P, and sequentially overlaps the labels, thereby printing the label. A full-color image can be recorded and formed on one side.

  The recording unit 130 is provided with a detachable cap 133 that covers the nozzle forming surface 131a of the recording head 131, and a blade 134 that cleans the nozzle forming surface 131a by wiping the nozzle forming surface 131a to remove deposits and the like. I have. Here, the cap 133 and the blade 134 are relatively moved in the horizontal direction after the recording head 131 is moved in the vertical direction indicated by the arrow B in the drawing, thereby forming a closed space 133 s described later and forming the nozzle forming surface 131 a. Cleaning is performed.

  The cap 133 is moved to a position facing the nozzle forming surface 131 a of the recording head 131 and is detachably installed. The cap 133 is attached to the nozzle forming surface 131 a of the recording head 131 to form a closed space 133 s (see FIG. 2) in a closed state on the nozzle forming surface 131 a side of the ejection port 132. The cap 133 is arranged on each of the recording heads 131Y, 131M, 131C, and 131K, and is prepared so as to cover the side of the nozzle forming surface 131a where the discharge port 132 of each color ink I opens. Thus, the cap 133 shields the nozzle forming surface 131a of the recording head 131 from the outside air, so that unnecessary deposits and promotion of drying can be avoided as much as possible.

  The blade 134 is installed so as to move to a position where the blade 134 faces the nozzle forming surface 131 a of the recording head 131 and maintain a contact state so as to be able to move in parallel. The blade 134 moves by contacting with the nozzle forming surface 131a of the recording head 131, thereby wiping off the adhered matter such as ink remaining on the nozzle forming surface 131a and cleaning the same. Accordingly, the blade 134 can keep the nozzle forming surface 131a of the recording head 131 clean, and can prevent the attached matter such as the residual ink from being stained by rubbing against the label paper P or the like. The blade 134 is shown only in FIG.

  The recording unit 130 has an ink tank 131 </ b> T disposed above the recording head 131 so that the respective color inks I stored in the storage space (internal space) are discharged from the individual discharge ports 132. Has become. In the recording head 131, ink cartridges 136 for each color of yellow (Y), magenta (M), cyan (C), and black (K), which are arranged at the lower part of the printer 100, respectively correspond to the ink flow paths. Are connected via That is, the ink tanks 136T of the ink cartridges 136Y, 136M, 136C, and 136K (see FIG. 3) are connected to the ink tanks 131T of the recording heads 131Y, 131M, 131C, and 131K as external tanks so that the respective color inks I can be replenished and filled. ing. In the recording head 131, the remaining amount of ink in the ink tank 131T is obtained by detecting the liquid level of the ink I by a remaining amount sensor 139 (see FIG. 3) connected to the control unit 150. The control unit 150 appropriately controls the replenishment and filling of the ink I according to the acquired remaining ink amount.

  Specifically, as shown in FIG. 2, the recording unit 130 covers the ejection port 132 by the elastically deformable opening end 133 a of the cap 133 being abutted against the nozzle forming surface 131 a of the recording head 131. The closed space 133s is formed. In the cap 133, a communication hole 133h for communicating the internal closed space 133s to the outside is formed in a frame 133b constituting a bottom portion, and a suction pump 141 is connected to the closed space 133s so as to be able to suck the closed space 133s. The cap 133 (closed space 133s) of each recording head 131 is connected to a suction pump 141 through a common pressure chamber 142s, an open / close valve 143V, and a pressure adjustment chamber 144s. Here, the common pressure chamber 142s is formed in the holding member 142 that holds the cap 133 for each recording head 131, and each of the common pressure chambers 142s is made to have the same spacing between the closed space 133s in the cap 133. It has been extended to the proximity position. In addition, between the closed space 133 s in the frame 133 b of the cap 133 and the common pressure chamber 142 s in the holding member 142, an elastic joint 138 of an elastic material formed in a tubular bellows shape with open ends at both ends. And liquid-tightly connected. This elastic joint 138 has one end side of a cylindrical bellows shape fixed to the bottom surface of the frame 133b of the cap 133 around the communication hole 133h in a liquid-tight manner, and the other end side opened to the upper surface of the holding member 142 to form the common pressure chamber 142s. Liquid-tightly fixed around the communicating hole 142h.

  As a result, the closed space 133s in the cap 133 is sucked with the same suction force through the common pressure chamber 142s, so that a uniform negative pressure for sucking the ink I in the ejection port 132 of the recording head 131 is applied. Then, a recovery process of the ink ejection performance described later is performed. The common pressure chamber 142s closes the cap 133 by closing the open / close valve 143V and maintaining the pressure adjustment chamber 144s in a reduced pressure state by the suction pump 141, and then opening the open / close valve 143V and appropriately sucking the cap 133. The space 133s can be set to a negative pressure. That is, the negative pressure generating means is constituted by the cap 133 (closed space 133 s) and the suction pump 141 together with the pressure adjustment chamber 144 s and the common pressure chamber 142 s.

  As shown in FIG. 3, the recording unit 130 is connected between the recording head 131 and the ink tanks 131T and 136T of the ink cartridge 136 by a flexible tube 137 forming an ink flow path. 137V is installed. The ink tank 131T of the recording head 131 is connected to the pressure adjustment chamber 144s by a similar tube 145, and the tube 145 is provided with an open / close valve 145V. That is, the pressure adjustment chamber 144s is connected to the common pressure chamber 142s communicating with the closed space 133s in the cap 133 via the tube 143 provided with the open / close valve 143V. A tube 147 provided with an open / close valve 147V is connected to the pressure adjustment chamber 144s so as to communicate with the ink tank 131T of the recording head 131. The pressure adjusting chamber 144s is formed in a tank member (not shown), and is connected to a tube 148 provided with an open / close valve 148V so as to open and communicate with the outside air. Further, a pressure gauge 149 for measuring an internal pressure is installed in the pressure adjustment chamber 144s, and is connected to the control unit 150. Here, in the following description, the recording head 131 and the ink tanks 131T and 136T of the ink cartridge 136 may be appropriately omitted.

  As a result, the recording unit 130 attaches the cap 133 to the nozzle forming surface 131a of the recording head 131, opens and closes the open / close valves 137V, 143V, 145V, and 148V, and switches the suction path by the suction pump 141 (the pressure adjustment chamber 144s). Can be. Therefore, in the recording unit 130, for example, a process of replenishing and filling the ink I of the recording head 131, a process of restoring the ejection performance of the ejection port 132, and the like can be appropriately performed. Here, the following description will be made using only a process of filling the ink tank 131T of the recording head 131 with the ink I.

  For example, in the case of the process of filling the recording head 131 with the ink I, the cap 133 is attached to the nozzle forming surface 131a, and the open / close valves 137V and 145V are opened while the open / close valves 143V and 148V are closed. In this case, the flow of the ink I at the ejection port 132 is shut off, and a flow path is formed in which the ink tank 131T of the recording head 131 communicates with the pressure adjustment chamber 144s and the ink cartridge 136. Therefore, when the pressure of the pressure adjustment chamber 144s is reduced by the suction pump 141, the ink tank 131T of the recording head 131 is set to a negative pressure, and the ink I is sucked and filled from the ink cartridge 136.

  Further, in the case of the recovery processing of the discharge performance of the discharge port 132 of the recording head 131, the cap 133 is attached to the nozzle forming surface 131a, and the open / close valve 143V is opened while the open / close valves 137V, 145V, and 148V are closed. In this case, the closed space 133s communicating with the common pressure chamber 142s so that the ink I of the ejection port 132 can flow therethrough is communicated with the pressure adjustment chamber 144s via the opening / closing valve 143V. On the other hand, in the ink tank 131T of the recording head 131, the flow path communicating with the pressure adjustment chamber 144s and the ink cartridge 136 is shut off by closing the open / close valves 137V and 145V. Therefore, when the pressure of the pressure adjustment chamber 144s is reduced by the suction pump 141, the closed space 133s of the cap 133 is set to a negative pressure, and the ink I in the ejection port 132 of the recording head 131 is sucked. At this time, the ink tank 131T of the recording head 131 is in a state of being sucked through the ejection port 132.

  As shown in FIG. 4, the control unit 150 is configured such that a control unit 151 including a CPU (Central Processing Unit) is connected to various parts of the apparatus such as the recording head 131 via an interface so that various types of information can be exchanged. The control unit 151 executes the control program stored in the memory 152 to execute various parts of the apparatus including the suction pump 141 based on sensor information detected by various sensors such as the remaining amount sensor 139 of the recording head 131. Overall control. Thereby, the control unit 151 develops the image data received from the connected host PC terminal device E into a bitmap for each color in the memory 152 and controls the driving of the recording head 131 and the like so that the labeling paper P is printed. Image formation.

  At this time, the control unit 151 performs a control process such as a process of filling the recording head 131 with the ink I and a process of restoring the ejection performance of the ejection port 132 based on sensor information of various sensors such as the remaining amount sensor 139 of the recording head 131. To maintain high quality image formation. Here, the filling process of the recording head 131 with the ink I is appropriately executed by the control unit 151 based on the sensor information of the remaining amount sensor 139, for example. The control unit 151 receives the instruction from the host PC terminal device E and executes the process of restoring the ink ejection performance of the recording head 131. The start of the various processes is not limited to these, and the control unit 151 may execute the process in accordance with, for example, the ejection amount of the ink I or the standby time. In the host PC terminal device E, by performing an input operation of various instruction information and the like from an operation unit K such as a keyboard, control processing such as image data drawing can be executed and transferred to the printer 100.

  Specifically, for example, the remaining amount sensor 139 of the recording head 131 includes a common conductor 139a and an empty detection conductor 139b extending to the deepest portion of the ink tank 131T, and a full detection conductor 139c positioned at the uppermost portion. Provided and connected to the control unit 151. The remaining amount sensor 139 constitutes a liquid level lower limit sensor between the conductors 139a and 139b, and constitutes a liquid level upper limit sensor between the conductors 139a and 139c, and is used for immersion in the stored ink I of the ink tank 131T. A corresponding liquid level detection signal is output. The controller 151A receives a liquid level detection signal between the conductors 139a and 139b and between the conductors 139a and 139c of the remaining amount sensor 139, and calculates and acquires an ink amount (ink storage amount) in the recording head 131. Function as

  The control unit 151 functions as a valve opening / closing control unit 151B, a negative pressure control unit 151C, and a mechanical position control unit 151D based on the ink amount in the recording head 131 obtained from the liquid level detection signal of the remaining amount sensor 139. Then, the ink I filling process and the ejection performance recovery process are executed.

  The valve opening / closing control unit 151B generates an operation instruction based on various information including the ink amount in the recording head 131 by the arithmetic unit 151A, and executes drive control of various valves. For example, the valve opening / closing control unit 151B sends an operation instruction to the recording head valve unit 131U to appropriately open / close the opening / closing valve 145V installed on the recording head 131. The valve opening / closing control unit 151B sends an operation instruction to the cartridge valve unit 136U to appropriately open / close the opening / closing valve 137V installed in the ink cartridge 136. The valve opening / closing control section 151B sends an operation instruction to the negative pressure valve unit 141U to appropriately open / close the opening / closing valves 143V and 148V installed in the common pressure chamber 142s and the pressure adjustment chamber 144s.

  As the negative pressure control unit 151C, for example, an operation instruction is generated based on various information including the amount of ink in the recording head 131 by the calculation unit 151A, and the drive control of the suction pump 141 is executed to appropriately control the pressure adjustment chamber 144s. Reduce the pressure.

  The mechanical position control unit 151D generates an operation instruction based on various information including the amount of ink in the recording head 131 by the calculation unit 151A, and executes drive control of each unit of the apparatus. For example, the mechanical position control unit 151D sends an operation instruction to the recording head 131 to appropriately move the cap 133 and the blade 134 relative to each other. In addition, the mechanical position control unit 151D sends an operation instruction for preparing for suction of waste ink or the like to each unit around the suction pump 141 to appropriately move the corresponding member.

  More specifically, for example, when the control unit 151 obtains, as the calculation unit 151A, the calculation result that the ink I in the specific print head 131 is consumed and becomes an empty ink amount, the control unit 151 according to the control program in the memory 152 The process of filling the ink tank 131T with the ink I is executed.

  At this time, the control unit 151 functions as a valve opening / closing control unit 151B and a mechanical position control unit 151D, moves the cap 133 to form a closed space 133s, and closes the opening / closing valves 143V and 148V, while closing the opening / closing valves 137V and 145V. Open. Thereby, the flow to the common pressure chamber 142s of the closed space 133s is blocked, and the flow of the ink I through the ejection port 132 of the recording head 131 is restricted. Further, a fluid flow path (tubes 137 and 145) from the ink cartridge 136 to the suction pump 141 via the ink tank 136T of the recording head 131 and the pressure adjustment chamber 144s is formed.

  Thereafter, the control unit 151 sets the ink tank 131T of the recording head 131 to a negative pressure by reducing the pressure in the pressure adjustment chamber 144s, and starts suction filling of the ink I of the corresponding color from the ink cartridge 136. The control unit 151 obtains, as the calculation unit 151A, a calculation result indicating that the ink I in the ink tank 131T of the target recording head 131 is full, and detects an increase in the amount up to the set threshold amount, and then opens and closes the open / close valve 137V. 145V is closed, and the filling process of the ink I ends. The ink tank 131T of the recording head 131 is prepared by setting the pressure regulating chamber 144s in a reduced pressure state by the suction pump 141 with the opening / closing valve 145V closed, and opening the opening / closing valve 145V appropriately to make the negative pressure. You may make it suction. It should be noted that the ink tank 131T of the recording head 131 may be driven by the suction pump 141 each time to suck the negative pressure through the pressure adjustment chamber 144s. Here, in the present embodiment, the fullness of the ink tank 131T of the recording head 131 is set as the threshold amount of the ink amount, but the present invention is not limited to this. For example, as will be described later, a threshold amount for increasing the amount of ink to such an extent that the remaining amount of air in the ink tank 131T is reduced so as to limit the suction of the ink I from the ejection port 132 to an effective degree is set. It may be.

  Further, when the control unit 151 receives a predetermined instruction command from the connected host PC terminal device E (driver software), the control unit 151 controls the discharge performance of the discharge port 132 of the print head 131 to be processed according to the control program in the memory 152. Execute the recovery process.

  At this time, the control unit 151 functions as the calculation unit 151A, and calculates and acquires the amount of ink in the ink tank 131T for each recording head 131, including the target other than the recovery processing target. Further, the control unit 151 functions as a valve opening / closing control unit 151B and a mechanical position control unit 151D, moves the cap 133 to form a closed space 133s, and appropriately opens / closes the opening / closing valves 137V, 143V, 145V, and 148V. Specifically, the open / close valves 143V and 148V around the common pressure chamber 142s and the pressure adjustment chamber 144s are closed. Further, the opening / closing valves 137V and 145V around the recording head 131 to be subjected to the recovery process are closed, while the opening / closing valves 137V and 145V around the recording head 131 not to be subjected to the restoration process are opened. Thereby, the flow to the common pressure chamber 142s of the closed space 133s is blocked, and the flow of the ink I through the ejection port 132 of the recording head 131 is restricted. Further, an ink filling flow path (a fluid flow path from the ink cartridge 136 to the suction pump 141 via the pressure adjusting chamber 144s) for filling the ink I into the ink tank 131T of the recording head 131 which is not the target of the recovery processing is formed.

  Thereafter, the control unit 151 sets the ink tank 131T of the recording head 131 that is not the target of the recovery processing to a negative pressure by reducing the pressure in the pressure adjustment chamber 144s, and starts suction filling of the ink I of the corresponding color from the ink cartridge 136. The control unit 151 closes the opened and closed valves 137V and 145V when the calculation unit 151A obtains the calculation result that the ink I in the ink tank 131T of the recording head 131 that is not the target of the recovery processing becomes full. The filling of the ink I ends. That is, the control unit 151 constitutes an ink amount adjusting unit.

  Further, the control unit 151 closes the open / close valves 137V and 145V around the recording head 131, and also functions as the negative pressure control unit 151C to open the open / close valve 143V of the common pressure chamber 142s. As a result, the closed space 133s in the cap 133 is set to a negative pressure due to the reduced pressure of the pressure adjustment chamber 144s communicated via the common pressure chamber 142s, and the ink I is sucked from the discharge port 132 of the recording head 131, and the ink discharge performance is reduced. Is performed. That is, the control unit 151 also configures a recovery control unit.

  More specifically, when the control unit 151 receives, for example, from the host PC terminal device E an execution instruction of a process for restoring the ejection performance of the ejection port 132 of the specific print head 131K, the control process shown in the flowchart of FIG. (Control method) is executed.

  First, the control unit 151 receives sensor information of the remaining amount sensor 139 for each recording head 131 (131Y, 131M, 131C, 131K) and calculates and acquires the amount of ink in each ink tank 131T (step S11). Next, the control unit 151 attaches the cap 133 to the nozzle forming surface 131a of each recording head 131 to form each closed space 133s (Step S12). Next, the control unit 151 closes the open / close valves 143V and 148V of the common pressure chamber 142s and the pressure adjustment chamber 144s, and closes the open / close valves 137V and 145V around the ink tank 136T of the recording head 131K to be subjected to the recovery processing (step S13). . Next, the control unit 151 opens the open / close valves 137V and 145V around the ink tank 136T of the recording heads 131Y, 131M, and 131C that are not targeted for recovery processing (step S14).

  Thus, the flow of the recording head 131 from the common pressure chamber 142s in the closed space 133s in the cap 133 is cut off, and the flow of the ink I in the ejection port 132 is restricted. Further, in the recording head 131 to be subjected to the recovery process, the fluid flow path (tubes 137 and 145) from the ink cartridge 136 to the suction pump 141 via the pressure adjustment chamber 144s is shut off, and the flow (suction) of the ink I into the ink tank 131T is performed. ) Is limited. On the other hand, in the recording head 131 not subject to the recovery processing, a fluid flow path (tubes 137 and 145) from the ink cartridge 136 to the suction pump 141 through the pressure adjustment chamber 144s is formed, and the flow of the ink I to the ink tank 131T (suction). ) Is acceptable.

  Next, the control unit 151 drives the suction pump 141 to reduce the pressure in the pressure adjustment chamber 144s, thereby setting the ink tank 131T of the recording heads 131Y, 131M, and 131C not to be subjected to the recovery process to a negative pressure (step S15).

  As a result, the recording heads 131Y, 131M, and 131C that are not targeted for the recovery process are filled with the ink I of the corresponding color from the ink cartridges 136Y, 131M, and 131C in the respective ink tanks 131T.

  Next, the control unit 151 receives the sensor information of the remaining amount sensor 139 for each of the recording heads 131Y, 131M, and 131C that are not subject to the recovery processing, and calculates and acquires the ink amounts in the individual ink tanks 131T (step S16).

  Next, the control unit 151 checks whether any of the ink tanks 131T of the recording heads 131Y, 131M, and 131C that are not targeted for recovery processing is full (the filling of the ink I is completed) (step S17).

  In step S17, the control unit 151 that cannot confirm the recording head 131 in which the ink tank 131T is full returns to step S16 and repeats the same processing. In addition, in step S17, the control unit 151 that has confirmed the recording head 131 in which the ink tank 131T is full closes the open / close valves 137V and 145V around the recording head 131 (step S18).

  Next, the control unit 151 checks whether or not all of the ink tanks 131T of the recording heads 131Y, 131M, and 131C that are not subject to the recovery processing are full and the filling of the ink I is completed (step S19).

  In step S19, the control unit 151 that cannot confirm that all of the ink tanks 131T are full returns to step S16 and repeats the same processing. Further, in step S19, the control unit 151, which has confirmed that all of them are full, sets the pressure adjustment chamber 144s (the detection pressure of the pressure gauge 149) by the continuously driven suction pump 141 to a predetermined suction recovery negative pressure or less. It is checked whether the pressure has been reduced (step S20).

  As a result, the recording heads 131Y, 131M, and 131C that are not targeted for the recovery process are filled with the ink I of the corresponding color in the respective ink tanks 131T and are filled. Here, the recording head 131K to be subjected to the recovery process remains at the ink amount at the start of the recovery control process without performing the process of filling the ink tank 131T with the ink I of the corresponding color (when the set threshold amount is satisfied). Remains).

  In step S20, the control unit 151 which cannot confirm the pressure reduction below the suction recovery negative pressure in the pressure adjustment chamber 144s returns to step S12 as it is and repeatedly checks (continues the pressure reduction by the suction pump 141). Further, in step S20, the control unit 151 that has confirmed that the pressure has been reduced to the suction recovery negative pressure equal to or lower than the suction recovery negative pressure in the pressure adjustment chamber 144s stops driving the suction pump 141 (step S21). Thus, it is possible to prevent the suction pump 141 from being wastefully and continuously driven to waste power.

  Next, the control unit 151 opens the open / close valve 143V of the common pressure chamber 142s while keeping the cap 133 attached to the nozzle forming surface 131a of each recording head 131, and communicates with each closed space 133s (Step S22).

  Accordingly, the closed space 133s in the cap 133 of the recording heads 131Y, 131M, 131C, and 131K is made negative pressure by reducing the pressure in the pressure adjustment chamber 144s, regardless of whether or not the recovery processing is performed.

  At this time, in the recording head 131K to be subjected to the recovery processing, the ink tank 131T is not filled with the ink I, the remaining air is expanded more easily than the ink I, and the ink I in the ejection port 132 is necessary and sufficient. It is sucked. Therefore, the recording head 131K is replaced with the fresh ink I in the ink tank 131T for the ink I whose viscosity is increased in the ejection port 132, and the ejection performance is restored.

  On the other hand, in the recording heads 131Y, 131M, and 131C that are not subject to the recovery processing, the respective ink tanks 131T are filled with the ink I and the remaining air is small. For this reason, these recording heads 131Y and the like are mainly sucked (outflow) from the ejection port 132 due to a change in the volume of the ink I, and the unnecessary suction of the ink I from the ejection port 132 is restricted. .

  For this reason, for example, in the recording head 131K to be subjected to the recovery processing, 2.4 g of the ink I was sucked from the discharge port 132 to sufficiently recover the discharge performance. On the other hand, it was possible to limit the suction (outflow) of the ink I to 0.2 g for the recording heads 131Y and 131M that are not subject to the recovery processing and to 0.3 g for the recording head 131C.

  Next, the controller 151 moves the blade 134 together with the cap 133 to make contact with the nozzle forming surface 131a of the recording head 131 (step S23). As a result, the nozzle forming surface 131a of the recording head 131 is wiped by the blade 134, and the ink I sucked for restoring the ejection performance of the ejection port 132 remains and adheres to the label paper P or the like to contaminate it. That can be avoided beforehand.

  Next, the control unit 151 moves the cap 133 and the blade 134 to a home position that does not hinder the recording operation of the recording head 131 (Step S24). Next, the control unit 151 opens the open / close valves 137V and 145V around all the print heads 131 to return to a state in which steady operation is possible (step S25), and ends the ejection performance recovery processing.

  Therefore, the control unit 151 recovers the ejection performance by sucking the ink I from the ejection port 132 of the recording head 131K to be subjected to the recovery processing without unnecessarily consuming the ink I such as the recording head 131Y not to be subjected to the recovery processing. be able to.

  As described above, in the printer 100 of the present embodiment, the filling process of the ink I is avoided when the recovery process of the ink ejection performance of the recording head 131 is necessary, and when the recovery process is not necessary, , The ink tank 131T is fully filled (increased to the set threshold amount).

  Therefore, in the recording head 131 that does not need the recovery processing, the suction of the ink I from the ejection port 132 is limited without the ink I in the ink tank 131T being greatly expanded. On the other hand, in the recording head 131 requiring the recovery processing, the residual air in the ink tank 131T is greatly expanded, so that the ink I is sucked from the discharge port 132 as necessary and sufficiently, and the ink discharge performance is effectively recovered. .

  Therefore, the ink I can be appropriately sucked from the ejection port 132 of the specific recording head 131 according to the necessity of the recovery process of the ink ejection performance. For this reason, it is possible to effectively recover the ink discharge performance of the recording head 131 requiring the recovery process while suppressing unnecessary waste of the ink I.

  Here, in the above embodiment, the printer 100 using the four colors of ink I will be described as an example, but the invention is not limited to this. For example, a printer of a type that forms an image in a plurality of colors such as a single color, two colors, three colors, six colors, ten colors, and twelve colors can be suitably employed. Further, the present invention is not limited to a so-called line type ink jet recording type printer, but may be applied to a so-called serial type ink jet recording type printer.

  The scope of the invention is not limited to the exemplary embodiments shown and described, but also includes all embodiments that provide equivalent advantages to those intended. Furthermore, the scope of the present invention is not limited to the combination of features of the invention defined by each claim, but may be defined by any desired combination of specific features among all disclosed respective features. .

100 Printer 110 Paper unit 130 Recording units 131, 131Y, 131M, 131C, 131K, Recording heads 131T, 136T Ink tank 131a Nozzle forming surface 132 Discharge port 133 Cap 133s... Closed space 134... Blades 136, 136Y, 136M, 136C, 136K,... Conductor 139c Full detection conductor 141 Suction pump 142s Common pressure chamber 144s Pressure adjusting chamber 149 Pressure gauge 150 Control unit 151 Control unit 152 Memory E Host PC terminal device I: Ink P: Label paper

Claims (7)

A plurality of recording heads capable of storing ink therein, forming an image on a recording medium by discharging ink from discharge ports,
Negative pressure generating means for forming a closed space between the discharge port forming surface of the recording head and the discharge port formed therein to make the closed space a negative pressure;
Recovery means for causing the negative pressure generating means to function to make the closed space a negative pressure, thereby sucking ink from the discharge ports to recover ink discharge performance,
Ink amount adjusting means for adjusting the amount of stored ink in the recording head,
A control unit that performs the suction in a state where the ink storage amount in the print head that performs the suction is smaller than the storage amount of the print head that does not perform the suction, among the plurality of print heads;
An inkjet recording apparatus comprising: The negative pressure generating means,
A cap that forms the closed space between the ejection port forming surface of each recording head and
A suction pump that communicates with the closed space for each recording head and makes the closed space a negative pressure;
The inkjet recording apparatus according to claim 1, further comprising: The negative pressure generating means,
3. The ink jet recording apparatus according to claim 2, further comprising a common pressure chamber interposed between the closed space and the suction pump for each of the recording heads to equalize a communication distance to the closed space. The negative pressure generating means,
4. The pressure adjusting chamber according to claim 2, further comprising a pressure adjustment chamber interposed between the closed space and the suction pump for each of the recording heads and maintained in a state where the pressure is reduced by the suction pump. Ink jet recording device. The ink amount adjusting unit includes:
An external tank that communicates with the internal space of the recording head and stores ink in a refillable manner, and an open / close valve that opens and closes a communication flow path between the internal space of the recording head and the external tank,
While the ink ejection performance recovery process is not necessary, the open / close valve of the print head is opened to replenish the ink from the external tank into the internal space of the print head up to a predetermined or predetermined threshold amount,
2. The air remaining in the internal space of the recording head without refilling the ink by closing the on-off valve of the recording head requiring the ink ejection performance recovery processing. Item 5. The ink jet recording apparatus according to any one of items 4. The ink amount adjusting unit includes:
6. The ink jet recording apparatus according to claim 5, wherein an amount of ink stored when the recording head is fully filled with ink is set as the threshold amount. A suction method capable of storing ink inside, and suctioning a plurality of recording heads that perform recording by discharging ink from discharge ports formed on a discharge port forming surface,
Among the plurality of print heads, an ink amount adjusting step of reducing the amount of ink stored in the print head that performs the suction, to be smaller than the amount of storage of the print head that does not perform the suction,
A suction step of forming a closed space for closing the discharge port forming surfaces of the plurality of recording heads, and suctioning ink in the discharge ports by setting the inside of the closed space to a negative pressure;
A suction method comprising:

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