JP5965860B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus.

  As a background art of this technical field, there is Patent Document 1 (Publication of Japanese Patent Laid-Open No. 10-264410). This gazette includes “a gutter 6 that collects ink particles 5 not used for printing in an inkjet recording apparatus, and a gutter 6”. The gutter base 15 that holds the gutter and the check valve 8 installed in the gutter base 15 constitutes the gutter unit 7, and the downstream side of the gutter 6 is connected to the check valve 8 and the downstream side of the check valve 8 The check valve 8 is normally configured to close the recovery path 11 and open the recovery path 11 when the suction force of the ink recovery pump 12b is applied. Has been.

JP-A-10-264410

In the so-called continuous ink jet recording apparatus described in Patent Document 1, as an example, ink particles are charged according to the contents of printing by a charging electrode and fly when passing through an electrostatic deflection field between the deflection electrodes. The direction is changed and used for printing.
On the other hand, the ink particles that are not charged by the charging electrode travel straight without being deflected by the deflection electrode and are received by the gutter, pass through the ink recovery path by the suction force of the ink recovery pump, and return to the ink container for reuse. It is a mechanism to do.
In the gutter, ambient air is simultaneously sucked when the ink particles are sucked and collected. Here, if the flow rate of the air sucked from the gutter decreases, there is a possibility that the ink overflows from the gutter. Further, when the flow rate of the air sucked from the gutter increases, the volatilization amount of the ink solvent in the ink recovery path increases, leading to deterioration in running cost.

  Further, in the conventional ink jet recording apparatus, it is difficult to detect the ink overflow from the gutter, and the operation operation may be continued even in the state where the ink overflow has occurred, and the periphery of the apparatus may be stained with ink.

  An object of the present invention is to provide an ink jet recording apparatus capable of preventing ink contamination around the apparatus due to ink overflow by early detection of occurrence of ink overflow from a gutter.

In order to solve the above problems, for example, the configuration of the claims is adopted.
The present invention relates to an ink jet recording apparatus, an ink container that stores ink for printing on a print object, a nozzle that is connected to the ink container and discharges pressurized ink, A charging electrode for charging ink used for printing discharged from a nozzle; a deflection electrode for deflecting ink charged by the charging electrode; and a gutter for collecting ink not used for printing; A micro charge charging unit that charges a micro charge on ink particles that are not used for printing, and a detection unit that detects a charge amount of the ink flowing in the gutter, and a ground potential on a part of the outer peripheral surface of the gutter. When a ground potential portion having a level is formed, an inner wall of the gutter and the ground potential portion are insulated.

  According to the present invention, ink contamination due to ink overflow can be prevented by detecting at an early stage that ink overflow from the gutter has occurred.

1 is an external perspective view of an ink jet recording apparatus. It is a perspective view which shows the use condition of an inkjet recording device. The path | route block diagram of an inkjet recording device is shown. It is a figure which shows the structure of Example 1 of this invention. It is the figure which expanded the gutter part of Example 1 of this invention. It is a time chart which shows the phase relationship between an excitation signal and the charging voltage for a phase search. It is the figure which showed the ink overflow from the gutter of Example 1 of this invention. It is a figure which shows the phase detection data at the time of the normal of Example 1 of this invention, and an ink overflow. It is an ink overflow detection flowchart of Example 1 of the present invention. It is a figure which shows the structure of Example 2 of this invention. It is the figure which expanded the gutter part of Example 2 of the present invention. It is the figure which showed the state which the collection | recovery flow volume of the gutter part of Example 2 of this invention fell. It is the figure which showed the ink overflow from the gutter of Example 2 of this invention. It is a figure which shows the phase detection data at the time of normal of Example 2 of this invention, the time of collection | recovery flow volume fall, and the time of ink overflow. It is an ink overflow detection flowchart of Example 2 of the present invention. It is a figure of the gutter which shows another form of Example 1 of this invention. It is a figure of the gutter which shows another form of Example 1 of this invention. It is a figure of the gutter which shows another form of Example 2 of this invention. It is a figure of the gutter which shows another form of Example 2 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to a following example.

<Apparatus exterior configuration>
FIG. 1 is an external perspective view of the ink jet recording apparatus of the present invention. The ink jet recording apparatus includes an operation display unit 3 in a main body 1 and a print head 2 outside. The main body 1 and the print head 2 are connected by a conduit 4.

<Usage of device>
Next, the use state of this ink jet recording apparatus will be described with reference to FIG.
The ink jet recording apparatus 300 is installed on a production line in a factory where food, beverages, and the like are produced, for example, the main body 1 is installed at a position where a user can operate, and the print head 2 is on a production line such as a belt conveyor 15. Is placed at a position where it can come close to the printing object 13 to be fed. In order to print on the production line such as the belt conveyor 15 with the same width regardless of the feeding speed, the encoder 16 that outputs a signal corresponding to the feeding speed to the ink jet recording apparatus 400 and the printing object 13 are detected. A print sensor 17 that outputs a signal for instructing printing to the inkjet recording apparatus 400 is installed, and each is connected to a control unit (not shown) in the main body 1. In accordance with signals from the encoder 16 and the print sensor 17, the control unit controls the charge amount and charging timing of the ink particles 7 </ b> C ejected from the nozzle 8, and charges while the print target 13 passes near the print head 2. The deflected ink particles 7C are attached to the print object 13 for printing.

<Device path configuration>
Next, the path configuration of the ink jet recording apparatus will be described with reference to FIG. FIG. 3 is a diagram showing the overall path configuration of the inkjet recording apparatus 400.

  First, the ink supply path of the ink jet recording apparatus 400 of this embodiment will be described. The main body 1 is provided with a main ink container 18 that holds the circulating ink 7A, and the main ink container 18 has a reference amount that is appropriate for holding the liquid in the main ink container 18 inside. A liquid level sensor 46 is provided for detecting whether or not the liquid level has been reached.

  The main ink container 18 is connected to the viscosity measuring device 43 via the path 201 in order to grasp the viscosity of the ink 7A in the main ink container 18. The viscosity measuring device 43 is connected to an electromagnetic valve (for supply) 34 that opens and closes the path via a path 202, and the solenoid valve (for supply) 34 is used to suck and pump ink 7 </ b> A via the path 203. It is connected to a pump (for supply) 24 to be used. The pump (for supply) 24 is connected via a path 204 to a filter (for supply) 28 that removes foreign matters mixed in the ink 7A.

  The filter (for supply) 28 is connected to a pressure reducing valve 33 that adjusts the pressure to an appropriate pressure for printing the ink 7A pumped from the pump (for supply) 24 via the path 205, and the pressure reducing valve 33 is connected to the path. A pressure gauge 31 that measures the pressure of the ink 7 </ b> A supplied to the nozzles via 206 is provided. The pressure gauge 31 is connected to a switching valve 42 provided in the print head 2 via a path 207 passing through the conduit 4.

  The switching valve 42 is connected via a path 208 to a nozzle 8 having a discharge port that discharges the ink 7A. The switching valve 42 is a three-way solenoid valve. An ink supply path 207 and a cleaning path 237 are connected to the switching valve 42, and the supply of ink and solvent to the nozzle 8 can be switched. A gutter 14 for capturing ink particles 7C that fly straight without being charged or deflected because it is not used for printing is disposed in the straight direction of the nozzle 8 outlet.

  Next, referring to FIG. 3, the ink recovery path of the ink jet recording apparatus 400 of this embodiment will be described. The gutter 14 is connected to the phase sensor 47 for measuring the charge amount of the collected ink via the path 211. The phase sensor 47 is connected to a filter (for recovery) 30 that removes foreign matters mixed in the ink disposed in the main body 1 via a path 212 passing through the conduit 4. ) 30 is connected via a path 213 to a solenoid valve (for recovery) 35 that opens and closes the path.

  The electromagnetic valve (for recovery) 35 is connected to a pump (for recovery) 25 that sucks the ink particles 7 </ b> C captured by the gutter 14 via a path 214. The pump (for collection) 25 is connected to the main ink container 18 via a path 215. The main ink container 18 is connected to the exhaust path 217, and the exhaust path 217 communicates with the outside of the main body 1.

  Next, referring to FIG. 3, the ink supply path will be described. The main body 1 includes an auxiliary ink container 19 that holds ink for replenishment. The auxiliary ink container 19 is connected to an electromagnetic valve 36 that opens and closes a path via a path 221. The electromagnetic valve 36 is connected to a merging path 223 connected to the ink supply path 203 via a path 222.

  Next, the ink circulation path will be described with reference to FIG. The nozzle 8 provided in the print head 2 is provided in the main body 1 through a path 237 passing through the conduit 4 in addition to the ink supply path 208 and is connected to an electromagnetic valve 37 that opens and closes the flow path. Has been. The electromagnetic valve 37 is connected to a pump (for circulation) 26 that sucks ink from the nozzles 8 through a path 226. The pump (for circulation) 26 is connected to a merging path 228 connected to an ink recovery path 215 via a path 227.

  Next, the solvent supply path of the inkjet recording apparatus 400 of FIG. 3 will be described. The main body 1 is provided with a solvent container 20 for holding a solvent for solvent replenishment. The solvent container 20 is connected to a pump (for solvent) 27 used for sucking and pumping the solvent through a path 231. It is connected. The pump (for solvent) 27 is connected to a solenoid valve (for solvent) 38 in order to open and close the flow path via a path 232, and the solenoid valve (for solvent) 38 is connected to the main ink via a path 233. The container 18 is connected.

<Outline of Configuration of Example 1>
Next, an embodiment of the ink jet recording apparatus 400 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a block diagram showing the configuration of the first embodiment, and FIG. 5 is a partially enlarged view of the gutter portion of FIG.

  The ink jet recording apparatus 400 surrounds the position where the ink 7A supplied by being pressurized by the ink supply pump 24 from the main ink container 18 is ejected from the nozzle 8 into the shape of the ink column 7B, and the tip of the ink 7A is separated to become the ink particle 7C. The deflecting electrode 12 includes a charging electrode 11 and generates a deflecting electric field for deflecting ink particles 7C that fly by charging in accordance with the amount of charge and directing the ink particles 7C to a print target (not shown). In FIG. 4, 12A is a ground electrode and 12B is a plus electrode), a gutter 14 that captures ink particles 7C that are not used for printing, and a small charge 504 in the ink particles captured by the gutter 14. And a phase sensor 47 for generating a phase detection signal corresponding to the charge amount of the ink particles 7D.

  Further, the ink drive pump 326 that controls the ink recovery pump 25 that recovers the ink 7E captured by the ink supply pump 24 and the gutter 14 in the main ink container 18, and the ink particles from the ink column 7B ejected from the nozzle 8 An excitation voltage generating circuit 327 for exciting an electrostrictive element (not shown) built in the nozzle 8 in order to make the timing of separation into 7C regular, a charging signal generating circuit 329 for printing, and a charging signal generating circuit for phase search 328 (In this embodiment, a phase search charge signal generation circuit is provided in addition to the print charge signal generation circuit 329. However, the charge amount is controlled by the control unit using only the print charge signal generation circuit 329. D / for converting the charging signal in the form of a digital signal output from the digital signal to the voltage signal in an analog form. The converter 330, an amplifier circuit 331 that amplifies the voltage signal in the form of an analog signal output from the D / A converter 330 and generates a charging voltage that is applied to the charging electrode 11, and a deflection voltage that is applied to the deflection electrode 11. A deflection voltage generation circuit 335, an amplification circuit 332 that amplifies the phase detection signal in the form of an analog signal output from the phase sensor 47, a phase determination circuit 333 that receives the amplified phase detection signal and determines whether the charging is good, and amplification An A / D converter 334 that inputs the phase detection signal thus obtained and performs A / D conversion is provided.

  The MPU 320 in the ink jet recording apparatus 400 configured as described above controls the pump drive circuit 326 via the bus line 321 to operate the ink supply pump 24 and the ink recovery pump 25, whereby the ink 7 </ b> A in the main ink container 18 is operated. Is supplied to the nozzle 8 by being sucked, pressurized, and ejected from the nozzle 8 in a column 7B shape, and the ink particles 7C captured by the gutter 14 are sucked and collected in the main ink container 18. The tip of the ink column 7B ejected from the nozzle 8 is separated into ink particles 7C. Imming in which the tip of the ink column 7B is separated into the ink particles 7C is generated by generating an excitation voltage by the excitation voltage generation circuit 327 and exciting the electrostrictive element of the nozzle 8 to vibrate the ink column 7B. On the other hand, it can be regulated to a predetermined phase.

  The charge amount of the ink particle 7C is proportional to the charge amount that the ink column 7B is charged by the potential of the charging electrode 11 when the ink particle 7C is separated from the tip of the ink column 7B. The charging signal generation circuit 329 for printing applies a charging voltage to the charging electrode 11 so that the charging amount necessary to deflect the ink particles 7C to a predetermined position when the tip of the ink column 7B is separated into the ink particles 7C. A charging signal for printing is applied to apply.

  The ink particles 7C charged according to the charging voltage generated on the basis of the charging signal for printing are electrostatically deflected while flying between the deflection electrodes 12 and adhere to the target position of the object to be printed (not shown). . The uncharged ink particles 7C travel straight and are captured by the gutter 14 and collected.

  The timing for generating the charging signal for printing is such that, when the ink column 7B is separated into the ink particles 7C, the charging voltage is applied to the charging electrode 11 so that the charge amount necessary for deflecting the ink particles 7C to a predetermined position is obtained. It is necessary that the timing can be applied.

  The MPU 320 executes a phase search for generating a charging voltage for printing at an appropriate phase relationship timing.

<Configuration of Gutter Part of the Present Invention (Example 1)>
Next, the form of the gutter unit in the inkjet recording apparatus 400 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a partially enlarged view of the peripheral configuration of the gutter 14 of FIG.

  In FIG. 5, 7C denotes ink particles that are not used for printing, and 7D denotes ink particles that bear a minute charge 504 among ink particles that are not used for printing. The ink particles 7 </ b> D are slightly deflected when passing through the deflection electrode 12, but are suppressed to an amount of charge that does not jump over the gutter 14. The gutter 14 is for collecting ink particles 7C and 7D that are not used for printing, and is made of a stainless steel pipe having an inner diameter of about φ1 [mm].

  The phase sensor 47 is a phase sensor for detecting a minute electric charge 504. The material of the phase sensor 47 is made of stainless steel having conductivity and solvent resistance. The gutter 14 and the phase sensor 47 are connected by a path 211, and the path 211 is made of an insulating material such as resin. The phase sensor 47 is connected to the pump (for recovery) 25 via a path 212.

  The gutter 14 is provided with a ground portion 501 having conductivity on the outer peripheral surface in the vicinity of the inlet of the ink particles 7C and 7D. The ground portion 501 is electrically insulated from the gutter 14 by the insulator 502. Has been. Furthermore, the ground portion 501 is at the ground potential level. The ground portion 501 and the insulator 502 need to be installed with the convex portion in the ink particle flying direction as small as possible or avoiding the flying direction of the ink particle 7C so as not to hinder the flying of the ink particles 7C used for printing. is there.

  When the ink particles 7C and 7D that are not used for printing land on the gutter 14, the ink particles 7C and 7D are sucked by the suction force generated by the pump (for recovery) 25 and flow as ink 7E in the recovery path. The ink 7E travels along the wall surface of the gutter 14, flows along with the gas 21A in the flow direction 503B, and is collected in the main ink container 18. For example, if the flow rate of the ink 7E is about 3.5 [ml / min] and the flow rate of the gas 21A is about 140 [ml / min], the ink 7E does not overflow from the gutter 14, and normally stable ink. Recovery is possible.

  Further, since the ink 7 used in the inkjet recording apparatus 400 is conductive, when the ink particles 7D having a minute charge 504 land on the wall surface of the gutter 14, the ink particle 7D travels along the ink 7E, and the minute charge 504 is indicated by an arrow. As shown in 504A, it flows to the phase sensor and generates a phase detection signal.

<Phase search method>
As an example of detecting the charging voltage application timing, FIG. 6 shows a charging waveform in each phase when the excitation signal serving as a reference for particle formation is divided into eight and a charging signal for a half cycle starting from each phase is applied.

  In the ink jet recording apparatus 400, in order to detect the optimum charging voltage application timing, the charging phase is shifted with respect to the excitation signal that is a reference for particle formation in a state where printing is not performed (printing and printing interval, etc.). A charging voltage that does not jump over the gutter 14 is applied, and the charge amount 504 at each phase is detected. That is, the phase search is performed by generating the phase search charging voltage.

  In order to generate the phase search charging voltage for the phase search, the phase search charging signal generation circuit 328 generates a charge signal for generating a plurality of types of phase search charging voltages whose phases with respect to the excitation voltage are changed. Occur. The charging voltage for phase search is set such that the ink particle 7D charged with this charging voltage has a deflection amount that does not jump over the gutter 14 (can be captured by the gutter 14), and the ink particle 7D charged with this charging voltage. The phase detection signal output from the phase sensor 47 according to the charge amount 504 is input to the phase determination circuit 333 and the A / D converter 334 via the amplifier circuit 332.

  The waveform of the phase detection signal output from the amplifier circuit 332 changes, for example, as shown in (a) to (c) of FIG. When the ink jet recording apparatus 400 is in a normal state, the waveform of the phase detection signal changes as shown in FIG. 8A in accordance with the change in the generation phase of the phase search charging voltage.

  The phase determination circuit 333 inputs such a phase detection signal, binarizes the input phase detection signal of each phase with the threshold level, and “1” indicates that the threshold level is exceeded, and does not exceed it. The object is determined to be “0” and input to the MPU 320. The MPU 320 determines that the phase in which the binarized phase detection signal has changed from “0” to “1” is the optimum phase for generating a charging voltage for charging the ink particles 7C, and uses that phase for subsequent printing. A charging signal for printing is generated so as to generate a charging voltage.

<Operation of the Present Invention (Example 1)>
Next, a detection method when the ink actually overflows in the inkjet recording apparatus 400 according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram illustrating ink overflow from the gutter according to the first embodiment. FIG. 8A is a diagram illustrating phase detection data in a normal state, and FIGS. 8B and 8C are diagrams. It is a figure which shows the phase detection data at the time of ink overflow.

  FIG. 7 shows a state in which the recovery ability of the ink 7E deteriorates and the ink 7F overflows from the entrance of the gutter 14. The ink overflow is highly likely to occur when the suction flow rate of the gas 21A from the entrance of the gutter 14 is reduced. The cause is a trouble in the pump (for recovery) 25 and the path (for recovery) 211 to 214. Possible sealing failure. If this state is continued, the ink 7F continues to overflow from the gutter 14, and there is a possibility that the periphery of the apparatus is stained with ink. Therefore, it is necessary to detect and deal with ink overflow at an early stage.

  In the embodiment, when the ink 7F overflows from the gutter 14, it contacts the ground portion 501, and the inner wall of the gutter 14 and the ground portion are electrically connected. In this case, the minute charge 504 flows to the ground portion 501 as indicated by an arrow 504B, and the phase sensor 47 cannot detect the minute charge 504.

  Therefore, when ink suction is normally performed in the ink collection path, there is no ink overflow, and the detection result of the phase sensor 47 as shown in FIG. When normal ink suction is performed as described above, there are about 3 to 5 phases exceeding the threshold level, and four phases are detected in FIG. 8A.

  Next, FIG. 8B shows a state where the ink is slightly overflowing. Overall, the value detected by the phase sensor 47 is small, and only one phase exceeds the threshold level.

  FIG. 8C shows the detection result of the phase sensor 47 when the ink overflows, and the minute charge 504 flows to the ground portion 501. Therefore, the phase sensor 47 does not detect minute charges.

  Accordingly, it is possible to detect ink overflow from the gutter 14 by monitoring this based on the phase detection data. Therefore, the occurrence of ink overflow from the gutter can be detected at an early stage, and ink contamination due to ink overflow can be prevented.

<Description of Gutter Overflow Detection Flow of the Present Invention (Example 1)>
Next, the phase search and ink overflow detection in the ink jet recording apparatus 400 in this embodiment will be described with reference to FIG. FIG. 9 is a control flow diagram from the phase search of ink particle formation timing and ink overflow detection to countermeasure.

  First, step S701 shows a state in which the ink 7C that has been made into particles is ejected from the nozzle 8, and the ink particles 7C are being collected from the gutter 14. Step S702 instructs phase search signal generation circuit 328 to generate a phase search voltage for performing a phase search.

  In step S703, phase detection data obtained by converting the detection signal output from the phase sensor 47 into a digital signal form when the phase search voltage is generated is acquired from the A / D converter 334.

  In step S704, the phase detection data acquired from the A / D converter 334 is binarized by comparing with a predetermined value (threshold level). The binarized data may be input from the phase determination circuit 333. Here, a value exceeding the threshold level is determined as “1”, and a value not exceeding the threshold level is determined as “0”.

  In step S705, the number of binarized values in step S704 and determined as “1” in one period (eight phases) is counted, and it is confirmed whether “1” is equal to or more than two phases. If there are two or more phases, it is determined as “YES” (the ink recovery state from the gutter is good), and the process proceeds to step S706. If “1” is one phase or less, it is determined as “NO” (ink overflow from the gutter 14), and the process proceeds to step S711.

  In step S706, it is determined that a normal phase search is being performed, and indicates that printing is possible. Thereafter, the process returns to step S702, and the change in charging timing with time is monitored by repeating steps S702 to S706.

Next, in step S711, since it is determined that ink has overflowed from the gutter 14, an operation for stopping the ejection of ink from the nozzles 8 is instructed to reduce ink contamination around the apparatus.
In step S712, the occurrence of abnormality is displayed on the display device 325, and the user is notified.

  In the present embodiment, the control flow has been described in which it is determined that “1” indicates that the threshold level is exceeded and “0” indicates that the threshold level is not exceeded. However, “0” indicates that the threshold level is exceeded and “1” indicates that the threshold level is not exceeded. May be defined and controlled.

<Effect of the present invention (Example 1)>
Thus, according to the present embodiment, the following effects can be obtained. When the ink collecting capacity is lowered and the ink overflows from the gutter 14, the phase sensor 47 is dropped to the ground so that it cannot be detected by the phase sensor 47, so that the ink overflow is detected at an early stage. It is possible to provide an ink jet recording apparatus that can be used. Further, an ink jet recording apparatus capable of reducing ink smear around the apparatus by performing an operation to stop the ejection of ink from the nozzles 8 after detecting an ink overflow is provided. Can be provided.

<Another form of gutter structure of the present invention (Example 1)>
Moreover, it is good also as using the gutter shown in FIG. 16 or FIG. 17 as a form of the gutter part used for Example 1 of this invention.

  First, the configuration of the gutter unit shown in FIG. 16 will be described. 16A shows the entire gutter portion, and FIG. 16B shows an enlarged view of the A portion of FIG. Note that description of parts common to the configuration shown in FIG. 5 is omitted, and only different parts are described.

  In FIG. 16A, a gutter 14C is used to collect ink particles 7C and 7D that are not used for printing, and is made of a stainless steel pipe having an inner diameter of about φ1 [mm]. The gutter 14C has an integral structure with a gutter block 531 manufactured from a resin (for example, material: PBT) material that is an insulator by insert molding. The gutter block 531 is fixed to the gutter base 532, and the path 211 is sealed by an O-ring 533. The path 211 in the gutter base 532 is connected to the phase sensor 47.

  In FIG. 16B, it can be confirmed that the gutter block 531 which is an insulator is provided with the ground portion 501 and the gutter opening 14C1 and the ground portion 501 are electrically insulated.

Next, the configuration of the gutter unit shown in FIG. 17 will be described. FIG. 17 (a) shows the entire gutter part, and FIG. 17 (b) shows an enlarged view of part B of FIG. 17 (a). Note that description of parts common to those shown in FIGS. 5 and 16 is omitted, and only different parts are described.
17 (a) and 17 (b), a gutter 14D is for collecting ink particles 7C and 7D that are not used for printing, and has a gutter opening 14D1 having an inner diameter of about φ1 [mm], and is an insulator. It is made of a resin (for example, material: PBT).

  As described above, by adopting the configuration of FIG. 16 or FIG. 17, mass production processing is facilitated in the gutter used in Example 1, which leads to cost reduction in manufacturing.

Hereinafter, the invention according to the second embodiment will be described with reference to the drawings. In addition, description about the part which is common in Example 1 is abbreviate | omitted, and mainly a different part from Example 1 is demonstrated.

<Configuration of the Present Invention (Example 2)>
An embodiment of an ink jet recording apparatus 410 according to Example 2 of the present invention will be described with reference to FIGS. FIG. 10 is a block diagram showing the configuration of the second embodiment, and FIG. 11 is a partially enlarged view of the gutter portion of FIG.

  In the ink jet recording apparatus, reference numeral 320 denotes a microprocessing unit (hereinafter referred to as MPU) that controls the entire ink jet recording apparatus 410. Reference numeral 321 denotes a bus line that transmits a data signal, an address signal, and a control signal of the MPU 320.

  Next, in FIG. 10 and FIG. 11, ink flow, particle formation, and charging signal detection will be described. The ink jet recording apparatus 410 detects the phase according to the amount of charge of the ink particles 7C that capture the ink particles 7C that are not used for printing, and the ink particles 7D that bear a minute charge 504 among the ink particles captured by the gutter 14B. A phase sensor A47A and a phase sensor B512 that generate signals are provided.

  Further, a pump drive circuit 341 that controls the ink collection pump 25 that collects the ink 7E captured by the gutter 14B in the main ink container 18, and an amplification circuit that amplifies the phase detection signal in the form of an analog signal output from the phase sensor A47A. 342, a phase determination circuit A343 that inputs an amplified phase detection signal and determines whether charging is good or bad, and an A / D converter A344 that inputs the amplified phase detection signal and performs A / D conversion.

  Furthermore, an amplification circuit 345 that amplifies the phase detection signal in the form of an analog signal output from the phase sensor B 512, a phase determination circuit B 346 that receives the amplified phase detection signal and determines whether charging is good, and an amplified phase An A / D converter B347 that inputs a detection signal and performs A / D conversion is provided.

  The MPU 320 in the ink jet recording apparatus 410 configured as described above controls the pump driving circuit 341 via the bus line 321 to control the operation of the ink supply pump 24 and the ink recovery pump 25 and the suction force. The ink 7A in 18 is sucked, pressurized and supplied to the nozzle 8 to be ejected from the nozzle 8 into a column 7B, and the ink particles 7C captured by the gutter 14B are sucked and collected in the main ink container 18.

<Configuration of Gutter Part of the Present Invention (Example 2)>
Next, the form of the gutter part in the inkjet recording apparatus 410 according to Example 2 of the present invention will be described with reference to FIG. FIG. 11 shows a partially enlarged view of the peripheral configuration of the gutter 14B of FIG.

  In FIG. 11, 7C is ink particles that are not used for printing, and 7D is ink particles that bear a minute charge 504 among ink particles that are not used for printing. The ink particles 7D are slightly deflected when passing through the deflection electrode 12, but are suppressed to an amount of charge that does not jump over the gutter 14B. 14B is for collecting ink particles 7C and 7D which are not used for printing, and is made of a stainless steel pipe having an inner diameter of about φ1 [mm]. 47A is a phase sensor A for detecting a minute electric charge 504, and the material of the phase sensor A47A is made of stainless steel having conductivity and solvent resistance. The gutter 14B and the phase sensor A47A are connected by a path 211, and the path 211 is made of an insulating material such as resin. Further, the phase sensor A 47 A is configured to be connected to the pump (for recovery) 25 via a path 212.

  In the gutter 14B, the gutter inlet member 511 constituting the inlet of the ink particles 7C and 7D is made of an insulator. The gutter entrance member 511 includes a phase sensor B512 and a ground portion 513, and the gutter 14B, the phase sensor B512, and the ground portion 513 are electrically insulated from each other.

  The ground portion 513 and the phase sensor B512 need to be installed with the convex portion in the ink particle flying direction as small as possible or avoiding the flying direction of the ink particle 7C so as not to hinder the flying of the ink particles 7C used for printing. is there.

  When the ink particles 7C and 7D that are not used for printing land on the gutter 14, the ink 7E travels along the wall surface of the gutter 14 by the suction force generated by the pump (for recovery) 25, and in the direction of the flow direction 503B together with the gas 21A. It flows and is collected in the main ink container 18. Here, for example, the flow rate of the ink 7E is about 3.5 [ml / min], the flow rate of the gas 21A is about 140 [ml / min], and the ink 7E does not overflow from the gutter 14B, and stable ink recovery is possible. Is possible.

  Further, since the ink 7 used in the ink jet recording apparatus 410 has conductivity, when the ink particles 7D having a minute charge 504 land on the wall surface of the gutter 14B, the ink 7E is transmitted through the ink 7E, and the minute charge 504 is changed to an arrow. As shown in 504A, it flows to the phase sensor and generates a phase detection signal.

<Operation of the Present Invention (Example 2)>
Next, a detection method when the ink recovery capability of the ink jet recording apparatus 410 according to the present invention is reduced and when the ink overflows will be described with reference to FIGS. 12, 13, and 14. FIG. 12 is a diagram showing that the ink recovery capability of the gutter 14B is reduced and the ink level is rising to the vicinity of the entrance of the gutter 14B. FIG. 13 is a diagram showing ink overflow from the gutter 14B. It is. FIG. 14 is a diagram showing phase data when the state (1) is normal, and the phase (2) and the state (3) are diagrams showing phase detection data when the recovery capability is reduced. FIG. 4) is a diagram showing phase detection data when ink overflows.

  FIG. 12 shows a state in which the recovery ability of the ink 7E is lowered and the ink level is in contact with the phase sensor B512. In such a state, the phase sensor 512 provided on the inlet member 511 and the ink 7E come into contact with each other, and the inner wall of the gutter 14B and the phase sensor B512 are electrically connected. In this case, the minute charge 504 flows to the phase sensor B 512 as indicated by an arrow 504C, and the detected value of the minute charge 504 becomes small or cannot be detected by the phase sensor A 47A.

  In this case, it is considered that the flow rate of the gas 21A is decreased in the paths (for recovery) 211 to 214. For example, the flow rate of the gas 21A is increased by increasing the frequency of the pump (for recovery) 25. By doing so, there is a possibility that it can be restored to a good ink recovery state (shown in FIG. 11).

  FIG. 13 shows a state in which the recovery ability of the ink 7E deteriorates and the ink 7F overflows from the entrance member 511 of the gutter 14B. In such a state, when the ink 7F overflows from the inlet member 511 of the gutter 14B, the ink contacts the ground portion 513, and the inner wall of the gutter 14B and the ground portion 513 are electrically connected. In this case, the minute charge 504 flows to the ground portion 513 as indicated by an arrow 504D, and the minute charge 504 cannot be detected by the phase sensor A 47A and the phase sensor B 512.

  Such an ink overflow is likely to occur when the suction flow rate of the gas 21A from the entrance of the gutter 14B is reduced. The cause is a trouble of the pump (for recovery) 25 and a route (for recovery) 211. There may be a sealing failure of ~ 214. If this state is continued, the ink 7F continues to overflow from the gutter 14B, and there is a possibility that the periphery of the apparatus is stained with ink. Therefore, it is necessary to detect and deal with ink overflow at an early stage.

  Next, phase detection data in each recovery state body will be described with reference to FIG. The state (1) in FIG. 14 indicates a normal recovery state, and the phase search is executed by the phase sensor A. In this state, the phase data is not detected because the phase sensor B is not in contact with the ink 7E.

  In the state (2), the phase data is detected by both the phase sensor A and the phase sensor B. This is a state in which the ink 7E is slightly in contact with the phase sensor B and the recovery capability is reduced. In this case, the total value of the phase sensor A and the phase sensor B is output as the phase detection result, and the phase search is executed.

  In the state (3), the phase sensor A detects no phase, and only the phase sensor B detects phase data. This is a state in which the recovery capability is further lowered than in the state (2). Also in this case, similarly to the state (2), the total value of the phase sensor A and the phase sensor B is output as the phase detection result, and the phase search is executed.

  In the state (4), the detected value of the phase is small also in the phase sensor B, and there is no phase exceeding the threshold level even in the detected data of the total value of the phase sensor A and the phase sensor B. This state shows the detection result of the phase sensor 47 when ink overflows, and the minute charge 504 flows to the ground portion 513.

  As described above, in the configuration of this embodiment, it is possible to detect the recovery state of the gutter 14B unit by monitoring the phase detection data.

<Description of Gutter Overflow Detection Flow of the Present Invention (Embodiment 2)>
Next, the MPU 320 control processing for phase search, recovery capability decrease detection, and ink overflow detection in the inkjet recording apparatus 410 in this embodiment will be described with reference to FIG. FIG. 15 is a control flow diagram from the phase search for ink particle generation timing to the detection and handling of ink overflow.

  First, Step S801 shows a state in which the ink 7C that has been made into particles is ejected from the nozzle 8, and the ink particles 7C are being collected from the gutter 14B.

  Step S802 instructs phase search signal generation circuit 328 to generate a phase search voltage for performing a phase search.

  In step S803, phase detection data obtained by converting the detection signal output from the phase sensor A47A into the digital signal form when the phase search voltage is generated is acquired from the A / D converter A344.

  In step S804, the phase detection data acquired from the A / D converter A344 is compared with a predetermined value (threshold level) to be binarized. The binarized data may be configured to be input from the phase determination circuit A343. Here, a value exceeding the threshold level is determined as “1”, and a value not exceeding the threshold level is determined as “0”.

  In step S805, the number of binarized values in step S804 determined as “1” in one period (eight phases) is counted, and it is confirmed whether “1” is equal to or more than two phases. If there are two or more phases, it is determined as “YES” (the ink recovery state from the gutter is good), and the process proceeds to step S806. If “1” is one phase or less, it is determined as “NO” (ink overflow from the gutter 14), and the process proceeds to step S811.

  In step S806, it is determined that a normal phase search is being performed, and the printable state is indicated. Thereafter, the process returns to step S802, and changes in charging timing with time are monitored by repeating steps S802 to S806.

  Next, in step S811, since it is determined that the ink recovery capability from the gutter 14B has been reduced, an operation to increase the recovery capability by increasing the drive frequency of the pump (for recovery) 25 is instructed.

  Step S812 sums the detection signals output from the phase sensor A47A and the phase sensor B512 when the phase search voltage is generated, and converts the phase detection data converted into a digital signal form into an A / D converter A344, Obtained from the A / D converter B347.

  In step S813, the phase detection data acquired from the A / D converter A344 and the A / D converter B347 is compared with a predetermined value (threshold level) to be binarized. The binarized data may be input from the phase determination circuit A343 and the phase determination circuit B347. Here, a value exceeding the threshold level is determined as “1”, and a value not exceeding the threshold level is determined as “0”.

  In step S814, the number of binarized values in step S813 determined as “1” in one period (eight phases) is counted, and it is confirmed whether “1” is equal to or more than two phases. If there are two or more phases, it is determined “YES” (no ink overflow from the gutter), and the process proceeds to step S815. If “1” is less than or equal to one phase, it is determined as “NO” (ink overflow from gutter), and the process proceeds to step S821.

  In step S815, it is determined that the phase search is possible and the printable state is indicated. Thereafter, the process returns to step S802, and the change in charging timing with time is monitored by repeating steps S802 to S806 or S802 to S815.

  Next, in step S821, since it is determined that the ink has overflowed from the gutter 14B, an operation for stopping the ejection of ink from the nozzle 8 is instructed in order to reduce ink contamination around the apparatus.

  In step S822, the occurrence of abnormality is displayed on the display device 325, and the user is notified.

<Effect of the present invention (Example 2)>
As described above, according to the ink jet recording apparatus 410 according to the present embodiment, it is possible to detect before the ink overflows from the gutter 14B when the ink recovery capability falls, and in that case, the pump By performing control to increase the suction force of (for collection) 25, it is possible to provide an ink jet recording apparatus that can prevent ink overflow.

  Further, when ink overflows from the gutter 14B, the phase search charging voltage is dropped to the ground so that it cannot be detected by the phase sensor A47A and the phase sensor B512, so that the ink overflows early. Ink jet recording in which the ink smear around the apparatus can be reduced by controlling the operation to stop the ejection of ink from the nozzle 8 when the ink overflow is detected. An apparatus can be provided.

<Another form of gutter structure of the present invention (Example 2)>
Moreover, it is good also as using the gutter shown in FIG. 18 or FIG. 19 as a form of the gutter part used for Example 2 of this invention.

  First, the configuration of the gutter unit shown in FIG. 18 will be described. FIG. 18A shows the entire gutter part, and FIG. 18B shows an enlarged view of the C part in FIG. Note that description of parts common to the configuration shown in FIG. 11 is omitted, and only different parts are described.

  In FIG. 18A, a gutter 14E is used to collect ink particles 7C and 7D that are not used for printing, and is made of a stainless steel pipe having an inner diameter of about φ1 [mm]. The gutter 14E has an integral structure with a gutter block 541 made of a resin (for example, material: PBT) material that is an insulator by insert molding.

  In FIG. 16B, the gutter opening 14E1 is formed integrally with the gutter block 541 that is an insulator, and the gland block 541 is installed on the gutter block 541 outside the gutter opening 14E1, and the gutter opening 541 is formed. The phase sensor B is installed in the gutter block 541 inside 14E1. Therefore, the gutter 14E, the phase sensor B, and the ground portion 501 are electrically insulated by the gutter block 541. Further, the phase sensor B 542 is covered with an insulator 542 in order to prevent electrical connection between the connection portion for sending a signal to the outside of the gutter opening 14E1 and the ground portion 501.

  Next, the configuration of the gutter unit shown in FIG. 19 will be described. FIG. 19A shows the entire gutter portion, and FIG. 19B shows an enlarged view of the D portion in FIG. Note that description of parts common to the configurations shown in FIGS. 11 and 18 is omitted, and only different parts are described.

  19 (a) and 19 (b), a gutter 14F is for collecting ink particles 7C and 7D that are not used for printing, and has a gutter opening 14F1 with an inner diameter of about φ1 [mm], and is an insulator. It is made of a resin (for example, material: PBT).

  As described above, by adopting the configuration of FIG. 16 or FIG. 17, mass production processing is facilitated in the gutter used in Example 1, which leads to cost reduction in manufacturing.

DESCRIPTION OF SYMBOLS 1 ... Main-body part, 2 ... Print head part, 3 ... Operation display part, 4 ... Conduit,
7A ... Ink (in main ink container 18), 7B ... Ink column, 7C ... Ink particle, 7D ... Ink particle with slight charge, 7E ... Ink in collection path, 7F ... Overflowed ink, 8 ... Nozzle, 9 ... Electrostrictive element, 11 ... charge electrode, 12 ... deflection electrode, 12A ... ground electrode, 12B ... plus electrode, 13 ... print object, 14 ... gutter, 14B ... gutter, 14C-14F ... gutter, 14C1-14F1 ... gutter opening , 15 ... belt conveyor, 16 ... encoder, 17 ... print sensor, 18 ... main ink container, 19 ... auxiliary ink container, 20 ... solvent container, 21 ... gas, 24 ... pump (for supply), 25 ... pump (recovery) , 26 ... pump (for solvent), 27 ... pump (for circulation), 28 ... filter (for supply), 29 ... filter (for recovery), 30 ... filter (for solvent), 31 ... pressure 33 ... Solenoid valve (for supply), 35 ... Solenoid valve (for recovery), 36 ... Solenoid valve (for replenishment), 37 ... Solenoid valve (for circulation), 38 ... Solenoid valve (for solvent) 39 ... Solenoid valve (for cleaning), 42 ... Switching valve, 43 ... Viscosity measuring device, 46 ... Liquid level sensor, 47 ... Phase sensor, 47A ... Phase sensor A, 51 ... Print head cover, 51A ... Slit,
201-208 ... path (for ink supply), 211-215 ... path (for ink recovery), 217 ... path (for exhaust), 221-222 ... path (for ink replenishment), 223 ... merging path, 225-227 ... Route (for circulation), 228 ... Merge route, 231 to 233 ... Route (for solvent replenishment), 235 ... Branch route, 236 to 237 ... Route (for cleaning),
300 ... Control unit, 301 ... Bus line, 302 ... Recording unit, 310 ... Power supply,
320 ... Micro processing unit, 321 ... Bus line, 322 ... Memory (ROM), 323 ... Memory (ROM), 324 ... Input panel, 325 ... Display device, 326 ... Pump drive circuit, 327 ... Excitation voltage generation circuit, 328 ... Charging signal generating circuit for phase search, 329... Charging signal generating circuit for printing, 330... D / A converter, 331... Amplifying circuit, 332. Voltage generation circuit, 341 ... pump drive circuit, 342 ... amplifier circuit, 343 ... phase determination circuit A, 344 ... A / D converter A, 345 ... amplifier circuit, 346 ... phase determination circuit A, 347 ... A / D converter A,
400 ... Inkjet recording device, 410 ... Inkjet recording device,
501 ... Ground part, 502 ... Insulator, 503A ... Flight direction of ink particles, 503B ... Flow direction of recovery path, 504 ... Small charge, 504A ... Flow direction of minute electricity, 504B ... Flow direction of minute electricity when ink overflows 504C: Flow direction of minute electricity when the recovery force is reduced, 504D: Flow direction of minute electricity when ink overflows, 511: Gutter inlet member, 512: Phase sensor B, 513: Ground portion,
531 ... Gutter block, 532 ... Gutter base, 533 ... O-ring, 541 ... Gutter block, 542 ... Insulator,
600 ... door, 610 ... front side of the lower part of the main body 1, 620 ... rear side of the lower part of the main body 1, 621 ... flow path board,

Claims (5)

An ink container for containing ink for printing on a print object;
A nozzle connected to the ink container and ejected by pressurized ink;
A charging electrode that is charged with ink discharged from the nozzle and used for printing;
A deflection electrode for deflecting ink charged by the charging electrode;
An ink jet recording apparatus comprising: a gutter that collects ink that is not used for printing;
A micro charge charging means for charging a micro charge to ink particles that are not used for printing;
Detecting means for detecting a charge amount of ink flowing in the gutter,
An ink jet recording apparatus, wherein a ground potential portion having a ground potential level is formed on a part of an outer peripheral surface of the gutter, and an inner wall of the gutter and the ground potential portion are insulated. The inkjet recording apparatus according to claim 1,
The ink jet recording apparatus according to claim 1, wherein the ground potential portion is provided at a peripheral edge near the opening of the gutter. The inkjet recording apparatus according to claim 1 or 2,
Determining means for determining the level of the amount of charge detected by the detecting means;
An ink jet recording apparatus, wherein when it is determined that the threshold value set by the determination means has not been exceeded, the control unit stops ink ejection from the nozzle. The inkjet recording apparatus according to any one of claims 1 to 3,
A second detection means for detecting the charge amount of the ink in the vicinity of the opening of the gutter;
A part of the inner peripheral surface near the gutter opening is formed of a conductor, the conductor is insulated from the ink landing wall of the gutter, and the conductor is connected to the second detection means. Inkjet recording apparatus. The inkjet recording apparatus according to claim 4,
A suction means for sucking ink in the gutter toward the ink container;
Second determination means for determining the level of the amount of charge detected by the second detection means,
An ink jet recording apparatus, wherein the controller increases the suction force of the suction means when it is determined that the threshold set by the second determination means is not exceeded.

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