JP2017200730A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve recovery efficiency of a floating droplet floating after separated from a droplet discharged from a liquid discharge head.SOLUTION: A liquid discharge device including a liquid discharge head 101 includes electrode members (141, 142) generating an electrical field in a position corresponding to an air flow 600 containing a floating droplet 504 floating after separated from a droplet discharged from the liquid discharge head 101 to efficiently recover the floating droplet 504 by electrostatic force.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a liquid ejection apparatus.

  2. Description of the Related Art There is known an inkjet image forming apparatus that discharges liquid from a recording head to form droplets, fixes the droplets on a recording medium (printing paper), and records information on the recording medium. A recording head of such an image forming apparatus forms liquid droplets by projecting liquid from a minute hole as a mechanism for ejecting liquid. Ideally, all of the ejected droplets are fixed on the recording medium. However, in reality, some of the droplets may be in a state of minute mist and float in the apparatus. A droplet that floats in the state of this minute mist is called a floating droplet.

  The image forming apparatus can also be said to be a liquid ejection apparatus. If the liquid ejected by the liquid ejecting apparatus is printing ink, the suspended liquid droplets as described above are called “ink mist”. If ink mist floats in the housing of the device and adheres to various places, it causes a problem. For example, when ink mist adheres to an optical sensor, the detection accuracy of the sensor is lowered, causing malfunction of the sensor or the entire apparatus.

  As described above, the ink mist floating in the apparatus must be collected. Therefore, in an ink jet printer which is a kind of the image forming apparatus exemplified above, a technique for collecting ink mist by providing charging filters on both sides of the moving path of the recording head is known (see, for example, Patent Document 1). ).

  The technique disclosed in Patent Document 1 collects ink mist that is moved by an air flow generated by movement of a print head (recording head) using static electricity. In the technique of Patent Document 1, an electric field is formed by disposing a charging portion at an opposing position on the ejection side of a recording head. In this case, there arises a problem that the distance between the ink mist raised by the airflow from the inside of the apparatus or the outside of the apparatus and the charged member becomes long, and the recovery efficiency of the ink mist is lowered.

  SUMMARY An advantage of some aspects of the invention is that it improves the recovery efficiency of floating droplets that are separated from and suspended from droplets ejected from a liquid ejection head.

  In order to solve the above-described problem, an aspect of the present invention is a liquid ejection apparatus including a liquid ejection head, which generates an air flow including floating droplets that are separated from and suspended from the droplets ejected from the liquid ejection head. It has an electrode member that generates an electric field at a corresponding position.

  According to the present invention, it is possible to improve the recovery efficiency of floating droplets that are separated from the droplets ejected from the liquid ejection head and float.

It is the schematic which shows the structure of one Embodiment of the liquid discharge apparatus which concerns on this invention. It is a functional block diagram which shows the function structure of the inkjet printer which concerns on this embodiment. It is a figure explaining the generation | occurrence | production cause of the ink mist which concerns on this embodiment. It is a figure explaining the mode of the alternating charge in the conveyance belt which concerns on this embodiment. It is a figure explaining a mode that the ink mist which concerns on this embodiment generate | occur | produces by the influence of the conveyance belt by which alternating charge was carried out. It is a figure explaining the scanning direction by the carriage which concerns on this embodiment. It is a figure explaining the example of the ink mist which floats by the scanning of the carriage which concerns on this embodiment. It is a figure explaining the example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a figure explaining another example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a figure explaining another example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a figure explaining another example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a figure explaining another example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a figure explaining another example of the airflow which arises by the scanning of the carriage which concerns on this embodiment, and the movement of the ink mist by an airflow. It is a functional block diagram which shows the function structure of the ink mist collection | recovery mechanism which concerns on this embodiment. It is a flowchart which shows the flow of operation | movement in the ink mist collection | recovery mechanism which concerns on this embodiment.

  Hereinafter, embodiments of a liquid ejection apparatus according to the present invention will be described. The present invention relates to a liquid ejection apparatus having a mechanism for ejecting liquid to form droplets. In particular, a mechanism is provided for efficiently recovering floating droplets that are separated from the liquid and suspended by an airflow generated by a moving body that moves within a predetermined range in the apparatus. The gist of the present invention is to efficiently collect floating droplets by generating an electric field in consideration of the direction of airflow and the state in which floating droplets are likely to float.

[Hardware configuration of liquid ejection device]
Next, an ink jet printer 1 which is an embodiment of a liquid ejection apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram schematically showing a hardware configuration of main parts of the ink jet printer 1. The ink jet printer 1 includes a head unit 100, a transport unit 200, a paper feed unit 300, and a paper discharge unit 400.

  The head unit 100 includes a recording head 101 and a carriage 110 that carries the recording head 101. The recording head 101 is a liquid discharge head that discharges ink 501 described later to form droplets 502. As the carriage 110 moves according to scanning, the recording head 101 also moves according to scanning. Details of the movement of the carriage 110 and the movement of the recording head 101 will be described later.

  The conveyance unit 200 includes a conveyance belt 201, a conveyance roller 202, a tension roller 203, a charging roller 204, a tip pressure roller 205, and a conveyance guide 206. The conveyor belt 201 is an endless belt and is stretched between the conveyor roller 202 and the tension roller 203. The conveyance belt 201 is fed while maintaining a state where the conveyance belt 202 and the tension roller 203 are stretched with a predetermined tension. The conveyance belt 201 is a member for conveying the paper 301 fed from the paper feeding unit 300 in a predetermined direction on the lower side of the recording head 101.

  The charging roller 204 is disposed below the transport roller 202 and is disposed so that the transport belt 201 is sandwiched between the charge roller 204 and the transport roller 202. The charging roller 204 is in contact with the surface layer of the conveyor belt 201 and rotates according to the rotation of the conveyor belt 201. The charging roller 204 is a charging unit for charging the surface of the conveyance belt 201.

  The tip pressure roller 205 is arranged in a state of being urged toward the conveyance belt 201 as a pressing member for pressing the paper 301 against the conveyance belt 201. The sheet 301 is electrostatically adsorbed and fixed to the conveying belt 201 whose surface is charged by the tip pressure roller 205.

  A paper tray 302 of the paper supply unit 300 stores paper 301 that is an information recording medium. The paper 301 stored in the paper tray 302 is fed by a paper feed roller 303, and the paper 301 fed from the paper tray 302 is sent substantially vertically upward from the paper tray 302. The conveyance guide 206 changes the direction of the sheet 301 sent from the sheet tray 302 by approximately 90 degrees and copies it on the conveyance belt 201.

  The paper feed unit 300 includes a paper tray 302, a paper feed roller 303, and a paper separation pad 304. A paper tray 302 is a storage for storing paper 301 as a recording medium. The paper feed roller 303 takes out the paper 301 stored in the paper tray 302 one by one. The paper separation pad 304 is made of a material having a large friction coefficient, is disposed to face the paper feed roller 303, and is biased toward the paper feed roller 303.

  The sheet 301 taken out from the sheet tray 302 moves upward while being pressed against the sheet separation pad 304 by the sheet feeding roller 303. Thus, the sheets 301 are placed on the conveyance belt 201 one by one.

  The paper discharge unit 400 is configured to peel off and discharge the paper 301 on which an image or the like has been recorded by the recording head 101 from the conveyance belt 201. The paper discharge unit 401, the separation claw 402, the paper discharge tray 403, . The paper discharge roller 401 urges the paper 301 that is electrostatically attracted to the transport belt 201 toward the separation claw 402. The separation claw 402 is disposed in the vicinity of an end portion where the conveyance belt 201 changes its movement direction from horizontal movement downward, and separates the sheet 301 electrostatically attracted to the conveyance belt 201 from the conveyance belt 201. The paper discharge tray 403 is provided slightly upward from the same height as the paper 301 that passes between the paper discharge roller 401 and the separation claw 402 and is discharged. The height of the paper discharge tray 403 is a consideration for increasing the amount of paper 301 that can be stocked in the paper discharge tray 403.

[Functional configuration of liquid ejection device]
Next, the outline of the functional configuration of the inkjet printer 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a functional block diagram showing a functional configuration of the controller 111 that controls the entire inkjet printer 1.

  The controller 111 operates by being supplied with an operating voltage from the power supply 131 to the power supply circuit 121. The power supply 131 and the power supply circuit 121 are supply power supplies that also supply operating power for the entire inkjet printer 1 including the control controller 111. The floating droplet recovery mechanism, which will be described later, also operates in accordance with the voltage from the supply power source. An operation panel 136 for inputting and displaying information necessary for the operation of the inkjet printer 1 is connected to the control controller 111.

  The control controller 111 includes a host I / F (Interface) 115. The host I / F 115 is an interface that receives print data or the like via a cable or a network with an information processing device such as a personal computer, an image reading device such as an image scanner, and an imaging device such as a digital camera as an information supply side. is there. Information from the information supply apparatus is received via the host I / F 115.

  A CPU (Central Processing Unit) 112 has a central function of the controller 111 and controls the overall operation of the inkjet printer 1. The CPU 112 executes arithmetic processing such as reading and analyzing information (print data) from the information supply apparatus that is temporarily stored in a reception buffer included in the host I / F 115.

  The CPU 112 performs necessary image processing, data rearrangement processing, and the like, and then transfers the data to the head control unit 118. For example, font data stored in a ROM (Read Only Memory) 113 may be used to generate dot pattern data for outputting an image. Alternatively, image data may be developed into bitmap data by a printer driver on the host side and transferred to this apparatus.

  When the head control unit 118 receives image data (dot pattern data) corresponding to one row of the recording head 101, the dot control data for one row is sent as serial data to the carriage 110 in synchronization with the clock signal. Send it out. Further, the head control unit 118 sends a latch signal to the carriage 110 at a predetermined timing.

  The head drive unit 117 is a waveform generation circuit and amplifier that includes a DAC (Digital to Analog Converter) 116 that reads pattern data of a drive waveform (head drive signal) stored in the ROM 113 and D / A converts the drive waveform data. A drive waveform generation circuit configured is included.

  The carriage 110 is a head mounting unit on which the recording head 101 is mounted. The head mounting portion includes a shift register, a latch circuit, a level conversion circuit (level shifter), an analog switch array (switch means), and the like. The shift register receives a clock signal from the head controller 118 and serial data as image data. The latch circuit latches the register value of the shift register with a latch signal from the head control unit 118. The level conversion circuit changes the level of the output value of the latch circuit. The analog switch array is controlled to be turned on / off by a level shifter.

  With the above configuration, the recording head 101 is selectively applied with a required driving waveform included in the driving waveform by controlling on / off of the analog switch array to the actuator of the recording head 101 mounted in the carriage 110. Drive.

  The ink jet printer 1 includes a main scanning motor 126 that applies a driving force for moving the carriage 110 to perform main scanning, and a sub scanning motor 128 that drives the conveyance belt 201 to perform sub scanning. Yes. In addition, the inkjet printer 1 includes a supply motor 133 that drives the paper feed roller 303. The operation of each motor is controlled by the CPU 112 by reading a detection signal from each encoder sensor via an analog-digital converter.

  A main scanning encoder sensor 127 is provided as an encoder corresponding to the main scanning motor 126. A sub-scanning encoder sensor 129 is provided as an encoder corresponding to the sub-scanning motor 128. Further, a supply encoder sensor 132 is provided as an encoder corresponding to the supply motor 133.

  The main scanning encoder sensor 127 reads a detection signal for detecting the operation of the main scanning motor 126 and notifies the CPU 112 of this. The CPU 112 notifies a command signal to the main scanning motor driving unit 119 based on the notified detection signal. Based on this command signal, the main scanning motor driving unit 119 notifies the main scanning motor 126 of the driving signal.

  The sub-scan encoder sensor 129 reads a detection signal for detecting the operation of the sub-scan motor 128 and notifies the CPU 112 of this. The CPU 112 notifies the sub-scanning motor driving unit 120 of a command signal based on the notified detection signal. Based on this command signal, the sub-scanning motor driving unit 120 notifies the sub-scanning motor 128 of the driving signal.

  The supply encoder sensor 132 reads a detection signal for detecting the operation of the supply motor 133 and notifies the CPU 112 of this. The CPU 112 notifies the supply motor driving unit 122 of a command signal based on the notified detection signal. Based on this command signal, the supply motor driving unit 122 notifies the supply motor 133 of the drive signal.

  Each motor is excited and driven based on a drive signal notified from each motor drive unit. Each encoder sensor reads the operation of each motor as described above and feeds it back to the CPU 112. As described above, the rotation speed of each motor is controlled by the controller 111.

  The conveyance amount of the conveyance belt 201 is managed by the number of pulses of the sub-scanning encoder sensor 129 output corresponding to the driving of the sub-scanning motor 128. By outputting a control signal to the high voltage circuit for every fixed conveyance amount in the conveyance belt 201, the polarity of the high voltage generated in the high voltage circuit is reversed. Thereby, an alternating electric field which will be described later is formed in the expression of the conveyor belt 201.

  The controller 111 also includes a mist recovery voltage control unit 125. The mist recovery voltage controller 125 operates under the control of the CPU 112, controls the magnitude of the voltage supplied from the power supply 131 via the power supply circuit 121, and applies it to the mist recovery member 140. The mist recovery voltage control unit 125 controls the magnitude of the voltage applied to the mist recovery member 140 from the supply voltage, the timing for applying the voltage, and the like. Detailed description of the mist recovery voltage controller 125 and the mist recovery member 140 will be described later.

[Floating droplet generation mechanism]
Here, the generation mechanism of the ink mist 504 which is a floating droplet generated in the inkjet printer 1 will be described with reference to FIG. First, when a print request is made from the outside to the inkjet printer 1, the ink 501 for printing the image on the paper 301 along with a predetermined image forming process is directed toward the paper 301 toward the nozzle 102 of the recording head 101. It is discharged from. The ejected ink 501 becomes droplets 502 and falls on the conveyance belt 201 below the recording head 101 onto the sheet 301 being conveyed.

  The ink mist 504 may be generated when the trailing end of the falling droplet 502 is suspended and floating, or when the droplet 502 is floated as a minute liquid particle after reaching the paper 301. Therefore, the ink mist 504 is generated in the space between the recording head 101 and the conveyance belt 201. When an electric field is present between the recording head 101 and the conveyance belt 201, the droplet 502 is charged by electrostatic induction during the fall. When attention is paid to one droplet 502, a charge having a polarity different from the charging (positive potential) of the conveying belt 201 is induced on the conveying belt 201 side as shown in FIG. At this time, a charge having the same polarity as the polarity of the conveyance belt 201 is induced on the rear end side of the droplet 502. That is, the droplet 502 is electrically neutral.

  The ink mist 504 generated when the trailing edge of the droplet 502 in the above state is cut has a charge different in polarity from the polarity on the conveying belt 201 side, so that the charging of the ink mist 504 and the charging of the conveying belt 201 are the same. The repulsive force due to this causes the ink mist 504 to float.

[Mechanism of alternating charging]
Next, an electric field generated between the recording head 101 and the conveyance belt 201 will be described. The conveyor belt 201 is alternately charged. As shown in FIG. 4A, the conveyance belt 201 moves between the tension roller 203 according to the rotation of the conveyance roller 202. Simultaneously with the movement of the conveying belt 201, a high voltage (square wave) is alternately applied by the charging roller 204. Then, positive (plus) and negative (minus) voltages are alternately applied to the surface (insulating layer) of the conveyor belt 201.

  As a result, “negatively charged band 211” having a negative charge and “positively charged band 212” having a positive charge are alternately formed on the surface of the conveyor belt 201 in accordance with the application period of high voltage. . The charging bands as described above are alternately formed in the sub-scanning direction. As described above, by alternately applying voltages having different polarities, alternating electric fields are formed on the conveyor belt 201 by alternately arranging charging bands having different polarities on the surface of the conveyor belt 201. The

  FIG. 4B is an enlarged view of the surface of the conveyor belt 201 on which an alternating electric field is formed. As shown in FIG. 4B, a sheet 301 is placed on the conveyance belt 201 on which alternating charges are formed. As a result, the charge inside the sheet 301 is attracted to the electric field 500 on the conveying belt 201 to generate an attracting force. That is, the sheet 301 is attracted to the conveyance belt 201 and conveyed in the main scanning direction by the action of the alternating electric field.

  FIG. 5 is a diagram for explaining in more detail the generation of the ink mist 504 due to charging of the electrostatic attraction type conveyance belt 201. As shown in FIG. 5, in the space where the ink mist 504 is generated, an electric field is generated in which the conveyance belt 201 is alternately charged positively and negatively in the conveyance direction of the paper 301. In this case, the direction of the electric lines of force in the electric field 500 will be opposite in the future depending on the charging band of the conveyor belt 201. Accordingly, the ink mist 504 has both a positive charge and a negative charge.

[Operation of Carriage 110]
Next, the operation of the carriage 110 according to the present embodiment will be described. FIG. 6 illustrates a state where the conveyor belt 201 is viewed from the downstream side in the conveyance direction toward the upstream side (from the conveyance roller 202 side to the tension roller 203 side). In this case, the sheet 301 is conveyed from the near side to the far side. The carriage 110 moves back and forth in a direction orthogonal to the conveyance direction of the paper 301. The moving direction of the carriage 110 is the sub-scanning direction.

  The moving range of the carriage 110 changes according to the width dimension of the conveyance belt 201 and the width dimension of the paper 301. The carriage 110 reciprocates within the above range. The range of reciprocation of the carriage 110 is the inside of a space surrounded by the casing 103 (the casing right wall 102R and the casing left wall 102L) of the inkjet printer 1.

  Next, the airflow 600 generated in the internal space of the housing 103 by the carriage 110 and the recording head 101 that perform reciprocal movement will be described. As illustrated in FIG. 7A, when ink 501 is ejected from the carriage 110, ink mist 504 is generated in the space between the recording head 101 and the paper 301.

  When the moving direction of the recording head 101 at this time is, for example, the “forward path” direction in the sub-scanning direction as shown in FIG. 7B, the slip stream phenomenon due to the movement of the carriage 110 is caused in the moving direction of the carriage 110. Occurs on the other side. Due to the effect of the slip stream phenomenon, an air flow 600 that flows in a direction opposite to the moving direction of the carriage 110 is generated.

  The airflow 600 is a flow of air from the movement direction side of the carriage 110 toward the movement source side of the carriage 110, and flows in such a way as to be entangled in the movement source side of the carriage 110. The air current 600 causes the ink mist 504 generated between the carriage 110 and the transport belt 201 to flow and mist.

  Therefore, as shown in FIG. 7B, when the carriage 110 moves in the “return” direction in the sub-scanning direction, the ink mist 504 is caused by the air flow 600 in the direction opposite to the movement in the forward direction. Mist while moving

  Further, since the carriage 110 reciprocates within the moving range, when moving as shown in FIG. 7C, the ink mist 504 moves in the direction opposite to the moving direction.

  As described above, the ink mist 504 is generated in the moving range of the carriage 110 and the periphery thereof in response to the scanning with respect to the paper 301 that is the ejection surface on which the droplet 502 lands, and floats due to the influence of the air current 600.

  The ink jet printer 1 according to the present embodiment has a configuration as described below for the purpose of efficiently collecting the ink mist 504 that moves and scatters as shown in FIG. As shown in FIG. 8, the mist collection mechanism 700 according to this embodiment includes a mist collection member 140 and is configured with a power supply circuit 121 that functions as a supply power source that supplies voltage to the mist collection member 140.

[Embodiment 1]
An embodiment of a mist collection mechanism 700 mounted on a liquid ejection apparatus according to the present invention will be described with reference to the drawings. The mist collecting mechanism 700 according to this embodiment includes a first electrode member 141 that is charged with a positive charge when a positive voltage is applied, and a second electrode member 142 that is charged with a negative charge when a negative voltage is applied. A mist collecting member 140 is provided. A power supply circuit 121 supplies a voltage to the mist collecting member 140. In the mist collecting mechanism 700, the mist collecting member is constituted by at least one set of electrode members. The mist collecting mechanism 700 may be configured to apply a negative voltage to the first electrode member 141 and apply a positive voltage to the second electrode member 142.

  In the embodiment of the mist collecting mechanism 700 according to this embodiment, the voltage is applied to the first electrode member 141 and the second electrode member 142, whereby the ink mist 504 floating in a predetermined space is collected by electrostatic force.

  As shown in FIG. 8, by arranging the mist collecting member 140 on the inner surface of the housing 103, a potential difference is generated between the two electrode members. As a result, an electric field is generated between the two electrode members. When the ink mist 504 moving by the airflow 600 floats in the electric field generated by the mist collecting member 140, the ink mist 504 charged with the opposite polarity can be collected at each electrode.

  The mist collecting member 140 is disposed in the vicinity of the floating portion of the ink mist 504 that moves along the inner surface of the housing 103. In this case, the positively charged ink mist 504 is collected at the second electrode member 142 to which the negative electrode is applied, and the negatively charged ink mist 504 is recovered at the first electrode member 141 to which the positive electrode is applied. Collected.

[Embodiment 2]
Another embodiment of the mist collection mechanism 700 mounted on the liquid ejection apparatus according to the present invention will be described. In FIG. 9, the mist collecting mechanism 700 according to the present embodiment arranges the mist collecting member 140 on the side surface of the carriage 110. As already described, the carriage 110 reciprocates in the sub-scanning direction. In response to this reciprocating movement, an air flow 600 is generated in a direction opposite to the movement direction of the carriage 110 so that the air pushed away as the carriage 110 moves.

  The airflow 600 is in a state of being caught as shown in FIG. 9 on the side surface of the carriage 110 opposite to the moving direction of the carriage 110. Since the ink mist 504 also flows into the side surface of the carriage 110 by the airflow 600, the mist collecting member 140 is disposed at a position where the ink mist 504 moving along the airflow 600 gathers as shown in FIG.

  As shown in FIG. 9, the first electrode member 141 and the second electrode member 142 are arranged side by side in the height direction of the carriage 110. The height direction of the carriage 110 is a direction perpendicular to the sub-scanning direction (movement direction of the carriage 110) and the main scanning direction (movement direction of the conveyance belt 201), and is a vertical direction on the surface of the paper 301. .

  If the first electrode member 141 and the second electrode member 142 are arranged on the side surface of the carriage 110, when the carriage 110 reciprocates by sub-scanning, the airflow 600 moves to the opposite side of the moving direction. The ink mist 504 can be collected efficiently.

[Embodiment 3]
Another embodiment of the mist collection mechanism 700 mounted on the liquid ejection apparatus according to the present invention will be described. In FIG. 10, the mist collecting mechanism 700 according to the present embodiment arranges the mist collecting members 140 on both side surfaces in the moving direction when the carriage 110 reciprocates.

  In this case, as shown in FIG. 10, the first electrode member 141 and the second electrode member 142 constituting the mist collecting member 140 may be set as one set, and each set may be disposed on both side surfaces of the carriage 110. When the pair of the first electrode member 141 and the second electrode member 142 is arranged in this way, when the carriage 110 moves in the forward direction, the first electrode member 141 and the second electrode member arranged on the side surface on the return path side. 142 collects the ink mist 504. In addition, when the carriage 110 moves in the backward direction, the first electrode member 141 and the second electrode member 142 disposed on the side surface on the forward path side collect the ink mist 504.

  As described above, the ink mist 504 can be efficiently collected by arranging the mist collecting member 140 according to the present embodiment on the basis of the flowing direction of the airflow 600 generated along the moving direction of the carriage 110. . Specifically, the mist collecting member 140 is disposed on the side surface of the carriage 110 on the side where the airflow 600 flowing in the direction opposite to the moving direction of the carriage 110 flows. As a result, when the inkjet printer 1 performs bidirectional printing, the ink mist 504 generated when the carriage 110 moves in both directions can be efficiently collected.

[Embodiment 4]
Another embodiment of the mist collection mechanism 700 mounted on the liquid ejection apparatus according to the present invention will be described. In FIG. 11, the mist collecting mechanism 700 according to the present embodiment is disposed at a position along the moving direction when the carriage 110 reciprocates.

  As shown in FIG. 11, the mist collecting member 140 is arranged at a position parallel to the moving direction of the carriage 110. For example, the second electrode member 142 is disposed on the upper surface of the carriage 110, and the first electrode member 141 is disposed on the inner wall surface of the casing 103 of the inkjet printer 1, which is a surface facing the upper surface of the carriage 110.

  Note that the upper surface of the carriage 110 is the surface opposite to the direction in which the ink 501 is ejected from the recording head 101 in the carriage 110.

  The airflow 600 generated by the reciprocating movement of the carriage 110 passes through the gap between the upper side and the lower side of the carriage 110 and flows in the direction opposite to the moving direction of the carriage 110. Thus, an electric field 500 is generated by applying a potential difference between the upper surface of the carriage 110 serving as a passage for the airflow 600 and the inner wall surface of the housing 103 facing the surface.

  According to the mist collecting mechanism 700 according to the present embodiment, the electric field for collecting the ink mist 504 in the range surrounded by the inner surface of the apparatus, that is, the range in which the ink mist 504 floats, that is, the entire range of reciprocation of the carriage 110. 500 can be formed widely. Thereby, the collection efficiency of the ink mist 504 can be increased.

[Embodiment 5]
Another embodiment of the mist collection mechanism 700 mounted on the liquid ejection apparatus according to the present invention will be described. In FIG. 12, the mist collecting mechanism 700 according to the present embodiment is disposed at a position along the moving direction when the carriage 110 reciprocates.

  As already described, an air flow 600 is generated in the internal space of the casing 103 of the inkjet printer 1 due to the reciprocating movement of the carriage 110. As shown in FIG. 12, after the carriage 110 moves, the air flow 600 flows from the moving direction side of the carriage 110 to the original location 110B side where the carriage 110 exists.

  The movement range of the carriage 110 is defined within a predetermined width, and the carriage 110 reciprocates without exceeding the maximum width. FIG. 12 illustrates a state where the carriage 110 has moved to the maximum movement width. In this case, the airflow 600 generated by the movement of the carriage 110 flows through a gap existing above and below the carriage 110 while air ahead in the movement direction of the carriage 110 collides with the inner surface of the housing 103.

  Thus, the flow of the air current 600 is large in the vicinity of the end of the maximum movement width of the carriage 110. Accordingly, the degree to which the ink mist 504 floats tends to increase. Therefore, as shown in FIG. 12, if the mist collecting member 140 is disposed on the inner surface of the apparatus in the housing 103 positioned outside the moving width of the carriage 110, the ink mist 504 can be efficiently collected.

  As shown in FIG. 13, each of the inner wall surfaces of the housing 103 positioned on both outer sides of the movement width of the carriage 110 and each of the upper inner wall surfaces of the housing 103 in the vicinity of the maximum movement width of the carriage 110. Alternatively, a mist collecting member 140 may be disposed. In this case, for example, the second electrode member 142 is arranged on the inner surface of the housing 103 on the surface orthogonal to the moving direction of the carriage 110, and the inner surface of the housing 103 on the surface parallel to the moving direction of the carriage 110 is disposed. Arranges the first electrode member 141.

  Like the mist collecting mechanism 700 according to the present embodiment, the airflow 600 tends to stay at a position where the carriage 110 moves to the limit of the moving range and then starts moving in reverse by changing the moving direction. Easy to stay. Therefore, the electric field 500 is generated by arranging the mist collecting member 140 at this position. Accordingly, even when the ink mist 504 is likely to stay due to the stay of the airflow 600, the recovery efficiency of the ink mist 504 can be increased.

[Functional Configuration of Mist Collection Mechanism 700]
Next, details of the mist collecting mechanism 700 according to the present embodiment will be described. FIG. 14 is a functional block diagram showing a functional configuration of the mist collecting mechanism 700. As shown in FIG. As shown in FIG. 14, the mist collection unit 70 that implements a functional block of the mist collection mechanism 700 includes a data acquisition unit 71, a timing determination unit 72, a data storage unit 73, an applied voltage determination unit 74, and a voltage application. Part 75.

  The data acquisition unit 71 is a functional block that acquires an operation status (data related to an operation history) in the recording head 101 included in the inkjet printer 1. In the processing of the program executed by the CPU 112, data related to the operation history of the recording head 101 in the head driving unit 117 and the head control unit 118 is acquired. Therefore, the data acquisition unit 71 is realized by the program stored in the ROM 113, the CPU 112, the head driving unit 117, and the head control unit 118.

  The timing determination unit 72 determines the timing for applying a voltage to the mist collecting member 140 based on the ejection timing of the ink 501 by the recording head 101 and the timing of the movement operation of the carriage 110. That is, the timing determination unit 72 determines the timing at which the electric field 500 (see FIG. 5) is generated by applying two voltages having different polarities to the mist collection member 140.

  The data storage unit 73 stores the operation history data of the recording head 101 acquired by the data acquisition unit 71. That is, the data storage unit 73 is realized by the RAM 114 that records data necessary for the control of the CPU 112.

  The applied voltage determining unit 74 determines the value of the voltage applied to the mist collecting member 140 via the mist collecting voltage control unit 125. The applied voltage determination unit 74 determines the value of the applied voltage based on the operation history data of the recording head 101 stored in the data storage unit 73. Here, as a method for determining the voltage, for example, the operation history data is digitized and determined based on a value calculated by multiplying the data by a predetermined coefficient. As another method for determining the voltage, operation history data of the recording head 101 or the like may be stored in the ROM 113 in advance, and a predetermined applied voltage may be determined based on this data table.

  The voltage application unit 75 operates the mist recovery voltage control unit 125 to apply the application voltage determined by the application voltage determination unit 74 to the mist recovery member 140. As a result, a voltage having a predetermined magnitude is applied to the mist collecting member 140 at a predetermined timing. The voltage application unit 75 is realized by the CPU 112 and the mist recovery voltage control unit 125.

[Embodiment of Ink Mist Collection Method]
Next, the flow of processing of a program for operating the mist collecting unit 70 will be described using the flowchart shown in FIG. Each processing step will be described with reference numerals such as S1501, S1502,.

  First, the data acquisition unit 71 acquires data related to the operation history of the CPU 112, the head drive unit 117, the head control unit 118, and the sub-scanning motor drive unit 120 (S1501). Subsequently, a data acquisition process for storing the acquired data in the RAM 114 or the like from the data storage unit 73 is executed (S1502).

  Next, an operation timing determination process is executed by the timing determination unit 72 (S1503). In the operation timing determination process, it is determined whether or not it is time to apply a voltage to the mist collecting member 140. If not (S1503: NO), the process returns to the data acquisition process (S1501). If it is the timing to apply (S1503: YES), the data stored in the previous process is read (S1504).

  Subsequently, an applied voltage determination process for determining the magnitude of the voltage applied to the mist collecting member 140 is executed based on the read data (S1505). Here, as a method of determining the magnitude of the voltage, there is a method of using a data table acquired in advance in the ROM 113 by evaluation. In this case, using the data read in the data reading process (S1504), the voltage value stored in the data table may be read and the magnitude of the voltage value determined. Alternatively, the coefficient may be stored in the data table, and the magnitude of the voltage may be determined based on an arithmetic process using the data read in the data reading process (S1504) and the coefficient.

  Next, the determined voltage is notified to the mist collection voltage controller 125, and a predetermined voltage is applied to the mist collection member 140 (S1506).

  Next, the voltage application end timing to the mist collecting member 140 is determined (S1507). If it is not the end timing of voltage application (S1507: NO), the process returns to the determined voltage application process. If it is the end timing of voltage application (S1507: YES), the CPU 112 notifies the mist recovery voltage control unit 125 of the end of voltage application, and the mist recovery voltage control unit 125 applies the voltage to the mist recovery member 140. Stop.

  As described above, according to the inkjet printer 1 including the mist collecting unit 70 according to the present embodiment, the ink mist 504 collecting process is executed based on the operation of the recording head 101. In this case, processing for defining the operation of the mist collecting member 140 that collects the ink mist 504 is performed based on the operation recording of the recording head 101 and the like. As a result, the optimum electric field 500 can be formed in accordance with the timing at which a large amount of ink mist 504 is generated.

  As in the inkjet printer 1 according to the present embodiment, the voltage application timing and the voltage value to the mist collecting member 140 are controlled so as to form the optimum electric field 500. As a result, the ink mist 504 is deposited on the first electrode member 141 and the second electrode member 142 constituting the mist collecting member 140. When the ink mist 504 is deposited on the surfaces of the first electrode member 141 and the second electrode member 142, the ink mist 504 occupies a portion having a high density of electric lines of force. If such deposition of the ink mist 504 is left unattended, formation of the optimum electric field 500 is hindered. However, the ink mist 504 can be prevented from being deposited by controlling the application timing and magnitude of the voltage applied to the mist collecting member 140 as in the inkjet printer 1 according to the present embodiment.

  Accordingly, the ink jet printer 1 can be operated while maintaining the collecting power of the ink mist 504, and the collecting efficiency of the ink mist 504 can be improved.

  According to the inkjet printer 1 according to the present embodiment described above, by including the mist collecting mechanism 700, the ink mist 504 that is a floating mist can be efficiently collected and the collecting action can be continued. The mist collecting mechanism 700 includes at least one set of electrodes that are charged with different polarities in a space inside the inkjet printer 1 through which an air flow 600 generated by a moving body passes and a space into which the air flow 600 flows. The floating mist is collected by utilizing the electrostatic force by the electric field generated by this set of electrodes.

  In order to generate the electric field, the mist collecting mechanism 700 determines the timing at which the voltage is applied to the electrode, the length of time for applying the voltage to the electrode, the magnitude of the applied voltage, and the like of the recording head 101 that generates the floating mist. Determine based on operating conditions. Thus, by adjusting the arrangement and voltage of the electrodes, the ink mist 504 that is a floating mist can be efficiently and continuously collected.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 70 Mist collection | recovery part 71 Data acquisition part 72 Timing determination part 73 Data storage part 74 Applied voltage determination part 75 Voltage application part 100 Head part 101 Recording head 102 Nozzle 103 Case 110 Carriage 111 Control controller 112 CPU
113 ROM
114 RAM
115 Host I / F
117 Head driving unit 118 Head control unit 119 Main scanning motor driving unit 120 Sub scanning motor driving unit 121 Power supply circuit 122 Supply motor driving unit 125 Mist recovery voltage control unit 126 Main scanning motor 127 Main scanning encoder sensor 128 Sub scanning motor 129 Sub scanning Encoder sensor 131 Power supply 132 Supply encoder sensor 133 Supply motor 136 Operation panel 140 Mist collection member 141 First electrode member 142 Second electrode member 200 Conveying unit 201 Conveying belt 202 Conveying roller 203 Tension roller 204 Charging roller 205 Tip pressure roller 206 Conveying Guide 211 Negative charging band 212 Positive charging band 300 Paper feed unit 301 Paper 302 Paper tray 303 Paper feed roller 304 Paper separation pad 400 Paper discharge part 401 Paper discharge low Error 402 separation claw 403 discharge tray 500 electric field 501 ink 502 droplet 504 ink mist 600 airflow 700 ink mist collecting mechanism

JP 2013-060023 A

Claims (7)

A liquid discharge apparatus comprising a liquid discharge head,
A liquid discharge apparatus comprising: an electrode member that generates an electric field at a position corresponding to an air current including floating liquid droplets that are separated and suspended from liquid droplets discharged from the liquid discharge head. The electrode member comprises two electrodes,
Voltages having different polarities are applied to the first electrode and the second electrode,
The first electrode and the second electrode generate the electric field at a position where the floating droplet is generated or a position where the droplet is moved by the air flow.
The liquid ejecting apparatus according to claim 1. A voltage determining unit for determining the magnitude of the voltage;
The voltage determination unit determines the magnitude of the voltage based on an operation state of the liquid ejection head;
The liquid discharge apparatus according to claim 2. The voltage determining unit determines the size of the voltage based on the size of the droplets or the number of droplets ejected from the liquid ejection head;
The liquid discharge apparatus according to claim 3. The first electrode and the second electrode are disposed on the side surfaces of the liquid discharge head that face each other in the direction in which the airflow moves the floating droplets according to the movement of the liquid discharge head.
The liquid discharge apparatus according to claim 2, wherein the liquid discharge apparatus is a liquid discharge apparatus. The first electrode is disposed on an upper surface of the liquid discharge head facing a space where the airflow flows,
The second electrode is disposed on the inner surface of the device facing the space through which the airflow flows.
The liquid discharge apparatus according to claim 2, wherein the liquid discharge apparatus is a liquid discharge apparatus. The first electrode is disposed on an inner surface of the apparatus outside the moving width of the liquid ejection head,
The second electrode is located outside the movement width of the liquid ejection head and is disposed on the inner surface of the apparatus orthogonal to the movement direction of the liquid ejection head.
The liquid discharge apparatus according to claim 2, wherein the liquid discharge apparatus is a liquid discharge apparatus.