JPH03500273A - Method and apparatus for optimizing phase and improving resolution in inkjet printers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] A method and method for optimizing phase and improving resolution in inkjet blinking Device Background of the invention Two miles standing The present invention is particularly suitable for use in inkjet printing, particularly in the form of continuous deflection of ink streams. Control droplet formation and charging in inkjet printers to improve image accuracy and quality. Concerning devices and methods for promoting improvement.

Nikai stand! look The ink-end printing industry has experienced rapid technological advances in the past. Naturally However, these advances are not fully satisfactory in controlling the placement of droplets onto the recording surface. I never created the means to go there. Therefore, manual work is done on a consistent basis. It was not possible to produce high-resolution images with minimal intervention.

Continuous flow inlets of the type disclosed in U.S. Pat. No. 4,639.739 (Johimsen) In the case of a jet printer, the ink flow starts from the capillary tube and follows a predetermined path toward the recording surface. is injected under pressure. The ink flow naturally stops at the so-called "droplet formation" point. Formed into drops. A portion of the droplet stream is charged to a first potential, while another portion is charged to a first potential. Therefore, two potentials exist. The droplet is then moved by an electric field placed inside the passage. By being separated, the droplet with one potential is deflected from the path and away from the recording surface. However, droplets with other potentials reach the recording surface.

In the past, controlling droplet placement and the amount of charge applied to the droplets was originally done manually. Intervention was required and adjustments to the problem were needed in this regard. U.S. Patent No. 3.9 16.421 (Hertz), the droplet size and formation point can be adjusted somewhat. It is known to use oscillator devices for control.

The devices disclosed in U.S. Pat. Nos. 4,639,736 and 3,916,421 are prior art. Features improved resolution compared to other inkjet printers in the industry However, they still suffer from resolution limitations in controlling droplet placement on the recording surface. There is.

The lack of control over droplet placement changes requires manual intervention to compensate for placement changes. This has a negative impact on both the quality of the image and the time required to obtain the image. I will lose it.

Mame two again! bag The purpose of the present invention is to use an inkjet printer that creates an image on a recording medium. The object of the present invention is to provide a method that enables highly accurate droplet placement.

It is a further object of the present invention to provide an integrated system for accurately reproducing images with minimal manual intervention. The purpose of the company is to provide a jet printer.

A further object of the present invention is to create an image by accurately arranging droplets on a recording surface. It is to provide law.

An inkjet printer incorporating the present invention uses pressure to move a capillary tube into a predetermined passageway. It is a continuous flow printer that ejects ink along the line. Piezoelectric crystal in periodic lateral direction Vibrations can be applied to the injection end of the capillary to greatly control the actual location of the droplet formation point. Ru. Charged tunnels located along the path and encompassing the point where the flow breaks up into droplets Selectively charge the droplets. A biasing device positioned further downstream determines a specific amount of charge. while allowing other droplets to reach the recording medium.

The present invention further provides an arrangement between the voltage applied to the charging tunnel and the periodic vibration of the piezoelectric vibrator. Contains devices for maintaining synchronous relationships. This device is capable of charging a single droplet. Make it. The control of the droplet formation point provided by the vibrator and the cooperation of this device allow for recording. Precise control of the amount of ink deposited on a specific area of the recording surface and the placement of droplets on the recording surface will be done.

Brief description of the drawing Figure 1 is a diagram of an inkjet printer embodying the present invention, and Figure 2 is a diagram of the printer. Diagram of the control circuit of.

Disaster left sitting seated seed l next day Yu Now, referring to FIG. 1, an inkjet printer incorporating the present invention has a hard drive. It comprises an inkjet 1 having a capillary tube 3 housed in a housing 9. Pon The conductive ink 4 (for example, a body resistance of less than approximately 200 ohms/cm) ) from the tank 13 to the inkjet 1. at the aft end of the jet Ink 4 comes into contact with charge adapter 5 . The above adapter 5 works as described below. It is actually grounded. The ink flows from the capillary tube 5 before acting as a nozzle 15. Driven out through the edge. The resulting ink stream 17 is a droplet at the droplet formation point 18. crushed into pieces. The piezoelectric vibrator 7 causes the nozzle 15 to vibrate laterally at the droplet formation point. Break the stream uniformly into droplets.

A charging mechanism, in this case a charging tunnel 21, through which the ink stream 17 passes. The tunnel 21 is designed to surround the droplet formation point 18. is positioned. The potential of the tunnel 21 is between the first level and the second level. Alternate selectively.

Ink: The front end of IXl"r takes a potential whose polarity is opposite to that of tunnel 21. . This is equivalent to an electric charge being induced at the end of the flow.

It is charged by the potential that exists between the end of stream 17 and 9. Certain droplets separate from the flow Any change in the electric potential of the membrane 21 after the droplet is charged does not affect the charging of the droplet. The main objective of the present invention is to develop a method for applying this charge to individual droplets. It's about controlling.

The droplets are introduced one after another into the deflection device 23, where an electric field connects the upper deflection electrode 25 and the lower waste Alternatively, it is added between the gutter electrodes 27. The upper electrode is the charging pole of the deflected droplet. The gutter electrode 27 has a potential of the same polarity as the ground potential. Thus, These droplets are directed into gutter electrode 27 by the electric field between electrodes 25 and 27. , while other droplets are either slightly or uncharged and are not deposited on the drum 43. The recording medium 41 is then reached.

The drum is rotated relative to the inkjet 1 by a drive device. The housing 9' is mounted on a base that moves parallel to the drum axis. Hidden Therefore, due to the uncharged droplets from the ink stream 17, the second line of the rask shape is effectively will be formed on top. In this case, the space 47 of the plant home is occupied by the medium 4 Not covered by 1.

Referring to FIG. It is connected to the virtual ground of the inverting input terminal of pin 149. At the end of the ink stream 17 This induction of charging (Figure 1) results in a ground-to-ground current in the ink stream, which causes the transducer 1 to The output voltage of 05 is equal to this current. This output is digitalized from the A/D converter 105. The data is sent to the file processing device 107. The processing device provides an output to the D/A converter 109. The phase control device 111 controls the phase delay imparted to the output of the crystal driven oscillator 113. Ru.

The crystal oscillation R113 controls the vibration of the vibrator 7. Its phase adjustment output also The voltage applied to channel 21 is timed.

That is, the output of the phase adjustment device 111 is applied to the data control device 115 for use in the printer. Outputs input data to voltage source 117. Thus, the voltage source 117 controls the vibration of the vibrator 7. The required potential is synchronized with the motion, but with a phase difference that controls the charge applied to individual droplets. is applied to the charging tunnel 21. In particular, in this special case, during each rotation of the drum 43 , the longitudinal strip not covered by the recording medium 41 is the inkjet 1 , the signal from device 53 (see FIG. 1) is sent to processing device 107. It will be done. At the same time, the processor enters a phase adjustment routine. First, the processing equipment is By applying a signal to the voltage source and applying an offset voltage to the tunnel 21, the liquid is All the drops are deflected to the gutter electrode 27. Thereafter, the control signal is transmitted to the data control device 115. In addition, the data controller 115 generates a pseudo-image data signal and outputs it to the voltage source 117. do.

At the same time, the processing device 107 causes the phase control device to “dazzle” the tunnel 21. The phase delay applied to the signal applied to the signal is periodically increased or decreased. At that time, the processing equipment A device 107 monitors the output of the A/D converter 105 and outputs the digital signal of the t-flow/1-pressure converter 150. record the total output. The processing device 107 is ink! Equivalent to the minimum Wit style in X17 Analytically determine the phase setting that depends primarily on the phase setting. This setting value It is possible to charge one droplet per single pulse applied to the tunnel 21. When the recording medium 41 is on the opposite side of the jet 1 again, the phase control device Added. I currently use frequencies in the 750-1200KHz range, especially 900-100KHz. A 0KH2 signal source is used to drive the crystal, and the entire cycle of crystal movement is approximately 1 mic. It is made to be in seconds. Similarly, the voltage source 117 that I use during printing The charging tunnel 21 becomes high potential or ground potential, and the ink droplets are selectively charged. Becomes charged or uncharged. However, in a certain way and under certain conditions Then, for printing, the droplet is slightly charged or biased, and the droplet is completely charged and deflected. It turns out that it is desirable to do so. To do this, adjust the ink nozzle position 15. simply adjust the DC bias voltage applied to the tunnel 21 by the voltage source 17. That's fine. In the same way, I installed a 1000-2000V deflection electrode and a ground gutter. The droplets to be deflected by the electrodes are exposed to a high voltage of -25 to -100V, especially around -50V. It was discovered that electrical charging can be achieved by a tunnel with a high potential. i used is applied to the charging tunnel 21 by the processor 107 during the phase cycle routine The reference offset voltage used is approximately 50V.

In this example, as mentioned earlier, the crystal oscillator 113 generates a signal to drive the crystal, and a signal to drive the crystal. Both provide information signals to the phase controller 111 regarding the state of 7. crystal 7 By periodically vibrating the inkjet, the ink flow when ejected is The slightly disturbed flow is at approximately the same distance from the nozzle 15 (when each droplet is formed). The droplets tend to break up into crystals (so that the spacing between them is almost constant), and - droplets form a crystal. so that it is fractured from the flow at a rate approximately equal to the Cronk cycle of the oscillator 113. It has become.

As mentioned above, the duration of the pulse directed into the charged tunnel by the voltage source is The duration is a multiple of the clock cycle of the crystal oscillator 113 and the phase being adjusted. mosquito So, -? & To charge the drop, the voltage source 117 is connected to the crystal oscillator 11 It pressure for 30 phase adjustment cycles (e.g., approximately 1 microsecond in my method) The voltage is applied to the charging tunnel 21. As explained earlier, the desired result is from the ink flow Controls the time between separating one droplet and separating the next droplet from the same ink stream. All that is required is to charge the potential of the tunnel 21 by controlling the tunnel 21.

It is understood that small changes in a system occur over time; such changes has a harmful effect on printing, so I decided to control the pulse generation of the charging tunnel. The band of droplets is determined with respect to the state of the signal from the crystal oscillator 113 to the crystal device 7 by providing stages. Optimized power. Thus, considerable control over droplet charging and placement is achieved. It can be carried out.

In the actual system I used and described, I used an inkjet medium We developed equipment and techniques to recalibrate the system after each rotation. In this case, the current The voltage is determined by measuring the current in the charging adapter 5 flowing through the /voltage converter 150. Measure. This occurs during the period in which space 47 is exposed to the inkjet; is performed when the test pattern signal is generated by the data controller 115. . It is understood that this measurement is also taken while the margins on the media are exposed to the inkjet. This measured voltage could then be used to recalibrate the system.

In the embodiment shown in FIG. 1, the inkjet printer is No. 36 and 4,668,359 with a single jet of the type discussed. It is. The invention can be easily incorporated into multijet inkjet printers. This is clear, and is actually defined as such. Similarly, this Not all of the various improvements illustrated in the patent are disclosed in the text. However, those skilled in the art can incorporate them into the text without departing from the nature and spirit of the invention. You can see that it can be easily incorporated.

Similarly, those skilled in the art will appreciate that the present invention can be applied to any ink cartridge using continuous flow deflection technology. This will clearly have wide applicability to biased links. This is true whether the ink is deflected into the gutter or for printing.

Additionally, assuming that other variables are controllable in some cases, the spirit and scope of the invention Interacting a piezoelectric crystal or other periodically vibrating device with a high-voltage drive within a Fluid that fractures from a charging tunnel or other ink stream by connecting It is reasonable that the device that charges the droplet can charge it to the desired potential in an appropriate amount of time. I can figure it out.

Although the device of the present invention was explained about an inkjet printer, the amount of liquid carried to the substrate It can also be applied to other fields where highly accurate control of For example, certain pharmaceuticals currently manufactured and in use require delivery of precise doses in small volumes. Essentially, the present invention allows the user to deliver a precise amount of liquid to the substrate. “The device also includes the pump and medication as mentioned above. It will consist of a tank, a jet, and a band 1i deflection device, with the board in place. It will be positioned along a regular path. The device was calibrated using the usual method described above. The exact dose required will then be delivered to the substrate. US special The points that should be ensured to ensure novelty through approval are as follows.

9 books x old books (no changes) FIG. 1 Yoshi, Commissioner of the Patent Office 1) Takeshi Moon 1. Patent application indication PCT/US 881033113, patent applicant 4. Agent 5. Date of submission of amendment: March 23, 1989 F! − (no change in content) Amendment claim scope 1. An apparatus for directing a precise amount of conductive liquid toward a substrate, comprising: A) a capillary tube; B) means for injecting liquid from said capillary in the form of a stream along a predetermined path; C) means for selectively charging the droplets of the liquid stream to a predetermined potential; and D) means for selectively charging the droplets of the liquid stream to a predetermined potential. a deflection device for deflecting the droplets so that only selected droplets reach the substrate; E) Compare the potential imparted to the droplets ejected from the capillary during normal operation of the device. F) a means for detecting at relatively short time intervals; and F) a charge level detected by the above detection means; a means of analyzing the bell; G) adjusting the phase of the means for selectively charging the droplets in response to the analysis means; and adjusting the timing of alternating the potential of the selective charging means. Therefore, means for ensuring that each droplet is charged to approximately a predetermined potential relative to the droplet; , said apparatus comprising:

2. Furthermore, it is equipped with a droplet formation control means, so that the size of the droplets formed from the liquid flow is approximately uniform. 2. The apparatus of claim 1, wherein the apparatus has a tendency to fracture from the flow at a substantially constant rate.

3. The droplet formation control means is mounted close to the nozzle end or the capillary, and A piezoelectric vibrator that operates the nozzle end of the tube, and the vibration rate of the vibrator connected to the same vibrator, 3. The apparatus of claim 2, further comprising a crystal oscillator for time-modulating the droplet formation rate.

4. When the potential detection means is connected to the capillary tube, the voltage induced in the ink is This current is detected and from the flow, the charge level of the crushed droplet 5 and the charge level analysis means are determined. determine the optimum phase corresponding to the minimum current induced in the liquid in the capillary of the charging means. 4. The device according to claim 3, wherein

6. Claim 5, wherein the optimum phase of the charging means is a multiple of the vibration rate of the liquid crystal oscillator. equipment.

7. The charge level analysis means described above corresponds to the minimum current induced in the liquid in the capillary. 2. The apparatus of claim 1, further comprising determining an optimum phase of said charging means.

8. In the method of operation of an inkjet printer, a single conductive liquid is drawn from a capillary tube. Pressure is ejected toward the surface to form a liquid stream that bursts into droplets. By changing the potential of an electrode placed close to the spout end of the capillary, selected droplets fractured from the flow of pressure ejected droplets having a first potential, and causing the other droplet to have a second potential; A droplet having the first potential is directed toward the surface, and a droplet having a second potential is applied to the groove. So, The current induced in the ink flow is relatively short during routine and normal operation of the device. upstream from the point of ejection of the liquid from the capillary tube. including measuring the current of A method comprising changing the timing of the charging step during the measuring step.

9. Further, shaking the jet end of the capillary tube at a rate proportional to the timing rate of the charging step. 9. The method of claim 8, comprising the step of moving.

10. The charging step alternates the charging of the droplet between the first and third potentials during the measurement step. Claim that all charged droplets collided on the gutter by The method according to item 8.

Heisei Year Month Day 1. Indication of case PCT/US 881033113, person making amendment Relationship to the case: Applicant 5. Date of amendment order: Self-issued Heisei Year Month Day 1. Indication of the case PCT/US 88/033113, person making the amendment Relationship to the case: Applicant 5. Date of amendment order: Self-issued 7. Contents of amendment as attached Amendment and Translation Submission Form (F + Copy of the translation attached to Article 184 and 7Q of the Act (with the contents) No change) International search report international search report PgoT/LIS signature/(:=l)

Claims (11)

[Claims] 1. a capillary tube through which a conductive liquid is injected as a single flow toward the substrate along a predetermined path; means for selectively charging droplets within the ink stream and directing certain droplets to said predetermined path; a deflection device that deflects only selected droplets to reach the substrate; means for detecting the level of charge applied to the droplet, and means for detecting the level of charge applied to the droplet means for determining appropriate timing for alternately selecting the selective charging means; A device consisting of 2. a capillary; a pressure generating device for ejecting a flow of conductive ink from the capillary; a charging electrode that selectively changes the potential of a selected portion of the ink flow; by selectively deflecting the ink stream portion according to the potential of the portion of the upper A predetermined portion of the recording ink stream impinges on the recording surface and another portion is directed to a waste collector. a deflection device that changes the potential of the charged electrode, a voltage source that changes the potential of the charged electrode, and a pulse from the same voltage source. By controlling the timing of and means for causing the ink to change only during the time interval between breakup of the droplets. jet printer. 3. Furthermore, a vibrator that periodically vibrates the jet from the capillary, and a cycle of the vibrator. By controlling the rate, the voltage source changes the pulse as a function of the oscillator. 3. The inkjet printer according to claim 2, further comprising a drive device comprising: 4. Furthermore, the potential of the droplet formed at the droplet formation point is analyzed to determine the power from the voltage source. A sampling device is provided to determine the appropriate phase shift for the drive of the pulse. The inkjet printer according to claim 3. 5. Furthermore, means for cyclically vibrating the jet from the capillary tube is provided, and the above-mentioned electrostatic charge is The timing of selectively alternating poles varies as a function of the capillary oscillations. 2. The apparatus of claim 1. 6. The charged electrode further generates voltage pulses to selectively alternate the potential of the charged electrode. a voltage source whose pulse duration to the charged electrode is equal to the clock cycle of the vibrating means. 6. The device of claim 5, wherein the device is a phase adjustment multiple of Kul. 7. The means for charging the droplets selectively alternates between the first and second potentials to charge the ink droplets. a charged electrode that generates an electric field through which the ink flow passes; A probe positioned along said path in a region containing the region broken into droplets. The inkjet printer according to claim 4. 8. Furthermore, a test pattern is generated and a droplet is applied to the droplet during the test pattern. A sampling means for monitoring the charging status and changing the potential applied to the charging electrode. 3. The ink according to claim 2, further comprising means for setting an appropriate timing signal to jet printer. 9. Additionally, a vibrator is used to vibrate the nozzle end of the capillary tube and the cycle of the vibrator is controlled. A clock device receives the timing signal from the sampling means and controls the vibrator. A phase control device that changes the phase of the potential with respect to the crystal speed. 8. The inkjet printer described in 8. 10. In the printing improvement method of inkjet printers, in the form of a continuous flow from a capillary By ejecting ink and selectively charging a portion of the ink, a certain droplet is attached to other liquids. imparting a high charge to the droplet and deflecting the ink droplet with one of the above charges. to allow a predetermined droplet to reach the recording surface, and adjust the charging timing of the droplet. droplet formation from the ink stream during the non-printing period of the print scan. Recalibrate the timing of charging of the droplets with respect to formation and test during such non-printing periods. A strut routine is generated and the appropriate timing of the charging stage of the droplet is determined. The droplet is at either a first or second charge level, and a significant amount of the drop is at either the first or second charge level. Said method of not having a charge that is between two charge levels. 11. Furthermore, the nozzle end of the capillary tube is periodically vibrated to control the rate of periodic vibration. the charging step alternating between a first and a second potential at the point of droplet formation; When an ink droplet breaks up from the ink stream by passing the droplet through an electrode tend to have a first or second charge level imparted to them. In the step of controlling the charging timing, the phase of the potential applied to the electrode is controlled by the nozzle. 11. The method of claim 10, comprising varying to periodic oscillations.