JPS6179671A - Control of charge phase in charge quantity control type multinozzle ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform stable printing recording by one detection electrode, by simultaneously applying the same charge phase detection pulse to all nozzles and setting the phase of the phase detection pulse, which is max. in the detection output from a single charge phase detection electrode, as the phase of the charge pulses of all nozzles. CONSTITUTION:A cycle T is divided into 8 phases and, for example, a pulse with a phase 0, a pulse with a phase 1, a pulse with a phase 3... are simultaneously applied to 8 nozzles in succession and charge quantities are detected by a single detection electrode. Large output is obtained in the case of the phase 2 and the phase 3, and the range from a nozzle 1 to a nozzle 6 is covered by the detection pulse with the phase 3 and output reaches a peak. Because the same phase detection pulse is simultaneously applied to all nozzles of set the phase, which brings the sum value of the charge quantities of ink droplets to a peak, to a charge phase as mentioned above, no separate phase is generated between adjacent nozzles can be reduced and a phase control method can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION Blood absorption separation The present invention is a charge-controlled inkjet recording method in which pressurized ink is ejected to form small droplets, and the small droplets are given a charge according to an image signal and printed on recording paper. The present invention relates to a device, and particularly to charging phase control in a multi-nozzle recording device.

In an inkjet recording device that performs printing by controlling the charge of ink particles, the phase of the electrical pulse applied to the charging electrode is adjusted so that the ink particles separate from the ink flow and become particles. must match the phase. This ink particle formation phase fluctuates unstably due to changes in ink viscosity and surface tension due to temperature changes, or changes in ink pressurization pressure. Therefore, it is necessary to detect the particulate phase and apply a printing charge signal to the charging electrode in synchronization with this particulate phase.As a method for this phase synchronization, the amount of charge is detected by electrostatic induction using a charge amount detection electrode. Conventionally proposed methods include: 1) detecting the charged state of ink particles without contact by installing an optical system at the deflection position; and 2) detecting the charged state of ink particles by installing a pressure-sensitive element at the deflection position. However, when using charge amount detection electrodes, there is always a risk of conductive ink adhering to the detection electrodes.
It is difficult to maintain a sufficiently high interelectrode impedance. In addition, when using an optical system, it is difficult to keep the optical system clean at all times, and when using a pressure-sensitive element, the size of the ink particles that collide with it is small, so there is no gain from the pressure-sensitive element. The pressure-sensitive signal itself is weak,
S/N is also low. Therefore, a method detects the amount of charge by colliding charged particles with a gutter that is partially conductive, charging a capacitor with the charge of the ink particles, and discharging it through a resistor (Japanese Patent Application Laid-Open No. 107142/1982). (Japanese Patent Application Laid-Open No. 55-84680), a gutter that is partially conductive is grounded through a resistor, and the amount of charge is detected by amplifying the voltage appearing on the resistor due to the collision of charged particles. (Japanese Publication No. 188379/1983) has been proposed, but if this is applied as is to a multi-nozzle case, it would be necessary to provide the same number of charged phase detection electrodes as the number of nozzles, which would be expensive and There are also problems with processing.

The present invention has been made in view of the above circumstances, and provides a charge amount control type multi-nozzle inkjet recording device that detects the charge phase using the detection electrode of This is intended to cause printing to be recorded.

In order to achieve the above object, the present invention applies the same charged phase search pulse to all nozzles at the same time, and determines the phase of the phase search pulse that maximizes the detection output obtained from a single charged phase detection electrode. is the phase of the charging pulse for all nozzles. Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows a schematic configuration of a charge amount control type multi-nozzle inkjet recording apparatus that implements the present invention. In FIG. 1, ink in an ink cartridge 1 is supplied to a pressure pump 2.
From solenoid valve 3. The liquid is fed under pressure through a filter 4 to a head 6 placed on a carriage 5. In the head 6, constant frequency pressure vibration is applied to the ink by constant frequency excitation of the electrostrictive vibrator 7. Therefore, the ink ejected from the nozzles of the nozzle plate 8 separates into ink particles after traveling a predetermined distance. A charging electrode 9 is disposed at this separation position, and when a charging voltage is applied at the time of separation, the ink particles are charged to a polarity opposite to the polarity of the charging voltage. The charged ink particles are deflected by the deflection electric field between the deflection electrodes 111 and 112 connected to the deflection power source 10 of -3.3KV, and are deflected onto the platen 1.
The image is printed on recording paper 13 on top of 2. Uncharged ink particles are captured by the gutter 14, sucked by the pump 15, and sent to the ink tank 16. 17 is a drive circuit for each of the recording devices, which is activated by commands from r/F18. The carriage drive circuit 171 drives the motor 19 and moves the carriage 5 by the wire 20 in a direction perpendicular to the plane of the paper. The head excitation circuit 172 excites the electrostrictive vibrator 7 to eject ink, and the charging circuit 17 applies a charging signal to the charging electrode 9. The phase search circuit 174 is used to control the charge phase of the ink droplet of each nozzle based on the amount of charge detected by one conductive gutter 14 during phase search (deflection electric field is turned off) (details will be described later). ). Further, the paper conveyance circuit 175 feeds the recording paper 13 during recording.

FIG. 2 shows the structure of the gutter 14 of the present invention shown in FIG. 1, in which the conductor gutter 14 is held by an insulator holder 21,
Further, the ink captured in the insulator holder 21 is sent to a recovery pump through an insulating tube 22. This gutter 14 is configured to capture non-imprinted ink drops from all nozzles.

FIG. 3 shows a control system for the recording apparatus of FIG. 1, and the same reference numerals as in FIG. 1 indicate the same contents.

In FIG. 3, the image signal is stored in the image memory 31 from l1030. This stored signal is read out by the output of the address counter 33 that counts the pulse signal from the timing generation circuit 32, and is read out by the charge control circuit 33.
Added to 4. The charge control circuit 34 reads a charge signal of a predetermined level from the charge code table 35 according to the image signal, and outputs the charge signal to the multiplexer 36 with a phase according to the signal from the timing generation circuit 32. Charging circuit 1 corresponding to each nozzle
7. A charging signal is applied to and amplified, and applied to each charging electrode 9. 37 is a charging circuit 17. 38 is a gain control and bias control circuit, and 38 is an amplifier.

Charge circuit 17 during phase search. A test signal is input to the gutter 14, and the gutter 14 receives it and checks whether or not it has been charged while changing the charging phase, searches for a charging phase where charging is normally performed, and fixes it at that phase.

This point will be explained using FIGS. 4 to 8.

Figure 4 shows the cutting length of each ink droplet in the case of 8 nozzles (distance from the nozzle end to separation into ink droplets)
The cutting length of each nozzle varies. This cutting variation is caused by variations in the nozzle diameter and the strength of pressure waves near the nozzle entrance, and in the present invention, a head with cutting variation within λ/2 is used as the characteristic.

FIG. 5 shows the cutting variation time corresponding to FIG. 4, and each nozzle separates into ink droplets at a period T.

In Figure 6, the period T is divided into 8 phases, and the pulse width is T/4.
In the present invention, a pulse of phase O, for example, is applied to eight nozzles simultaneously, then a pulse of phase 1, then a pulse of phase 3, and so on. The amount of charge is detected by one detection electrode (gutter 14 in FIG. 1).

The detection output at this time is shown in FIG. The result was 0°1.4
, 5, 6.7, the detection output is small, and the phase 222
A large output is obtained in the case of phase 3, and the search pulse of phase 3 covers from nozzle 1 to nozzle 6 as shown in FIG. 5, and as a result, the output reaches a peak. Therefore, a phase-locked charging pulse (FIG. 7) is created in phase 3 to charge all nozzles. Since this charging pulse has a wider pulse width than the phase search pulse, the nozzles 7 and 8 can also be covered and charged.

Although the phase search output depends on the conductivity of the ink in addition to the charge amount of the ink droplets, the phase can be fixed by searching for a peak. Also, the phase search pulse may have a pulse width other than T/4, but if it is T/8, for example, a smooth search output will not be obtained, but if it is T/4, a relatively smooth output will be obtained, and the peak detection becomes easier.

As described above, according to the present invention, in a multi-nozzle inkjet recording device, the same phase search pulse is simultaneously applied to all nozzles to determine the phase at which the total charge amount of each ink droplet reaches its peak. Since the charging phase is made to be the charging phase, there is no need to provide a charging phase detection electrode for each nozzle, and only one detection electrode is required (Also, since the charging pulse is the same for all nozzles, it is possible to Different phases are not generated, crosstalk can be reduced, and the phase control method can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a charge amount control type multi-nozzle inkjet recording device according to the present invention, FIG. 2 is a diagram showing the structure of a gutter according to the present invention, and FIG. 3 is a diagram showing a control system for the device shown in FIG. 1. , Fig. 4 shows the cutting length of each nozzle, Fig. 5 shows the cutting time of each nozzle, Fig. 6 shows the phase search pulse, and Fig. 7 shows the phase-locked charge pulse. FIG. 8 is a diagram showing the relationship between charging phase and detection output. 1... Ink cartridge, 6... Head, 9...
・Charging electrode, Ill, llz...deflection electrode, 13...
·Recording paper. 14... Gutter, 171... Carriage drive circuit. 172...head excitation circuit, 17. ...Charging circuit. 174... Phase search circuit, 175... Paper transport circuit. 31... Image memory, 32... Timing generation circuit, 35... Charge code table.

Claims (2)

[Claims] (1) The same charged phase search pulse is applied to all nozzles at the same time, and the phase of the phase search pulse that maximizes the detection output obtained from a single charged phase detection electrode is determined as the phase of the charged pulse for all nozzles. A charge phase control method in a charge amount control type multi-nozzle inkjet recording device, characterized in that: (2) The single charged phase detection electrode is a partially conductive gutter.
) A charge phase control method in a charge amount control type multi-nozzle inkjet recording device.