JPH0199852A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To improve printing quality by providing a detecting means to detect the ink mist density, and by modulating pixel signals to be recorded according to the signals of this detecting means. CONSTITUTION:An ink mist 6 deflected by a deflection electrode 10 is received by a gutter 11 and detected in the charge amount by a charge amount detection electrode 16. This charge amount is proportional to the number of mist particles; accordingly, if the charge amount detected within a fixed period of time is small, the number of mist particles is small. In other words, the density of mist 6 is low. When the density of mist is detected to be low, the time of no deflection is lengthened for such a correction that the density become as preset. When the detected discharge amount is large; namely, the mist density is detected to be high, this time of no deflection is shortened for correction of the density. Such a correction of density irregularity can provide improved quality of printing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording device, and more particularly to a recording head of an inkjet recording device that uses ink mist.

Prior Art An inkjet recording apparatus using the new term ink mist, which generates an ink mist and makes the ink mist fly and adhere to a recording medium to perform recording, is known, for example, from Japanese Patent Laid-Open No. 1983-1993.
111932, Japanese Patent Application Laid-Open No. 137436/1980, etc., but
In the invention disclosed in Publication No. 2, in order to keep the ink mist concentration constant, the number of ink mist generating vibrators to be driven is changed after a certain period of time has elapsed, such as when starting the apparatus, and also, The invention disclosed in Japanese Unexamined Patent Publication No. 50-137436 prevents ink from being supplied unless the ink temperature of the ink mist generating tank reaches a predetermined temperature. All of these methods are intended to keep the density of the ink mist constant, but they cannot be used immediately during recording, and therefore, the density of the recorded image cannot be controlled. The amount of mist generated by an ink mist generator is determined by: ■The viscosity of the ink; ■The components dissolved in the ink.

■The amount of ink in the mist generator (mist generator using ultrasonic waves), ■The waves and flow of the ink solution in the mist generator, ■The temperature of the surroundings and ink, etc. In the case of a mist generator, the propagation of ultrasonic waves is inhibited, resulting in a reduction in mist generation efficiency.

Purpose The present invention was made in view of the above-mentioned circumstances.
In particular, in mist-type inkjet recording devices, this was done to prevent print density from changing even if there are variations in the amount of ink mist generated, thereby eliminating deterioration in print quality, especially unevenness in shading. be.

Week-1 In order to achieve the above object, the present invention provides an inkjet recording apparatus that records ink mist on a recording medium.
In an inkjet recording apparatus that has a detection means for detecting the density of ink mist and modulates a pixel signal to be recorded according to a detection signal of the detection means, or that records ink mist on a recording medium, The present invention is characterized by having a detection means for detecting the density, and controlling the amount of ink mist generated in accordance with the density of the ink mist detected by the detection means. below,
An explanation will be given based on an example of the present invention.

FIG. 1 is a side cross-sectional view for explaining one embodiment of an inkjet recording apparatus according to the present invention, FIG. 2 is a perspective view of the whole see-through, and FIG. 3 is a flowchart for explaining the operation of this embodiment. In the figure, 1 is an ink container, 2 is an ink mist generator, 3 is a vibrator, 4 is a center wall, 5 is a fan, and 6 is an ink mist.

7 is an ink mist inlet, 8 is an air flow, 9 is a nozzle, 1
0 is a deflection electrode, 11 is a gutter, 12 is a printing mist, 13
is a recording paper, 14 is a mist return path, 15 is a charged electrode, 16
is a charge amount detection electrode with multiple nozzles as shown in Figure 5.
The nozzle 9 has a deflection electrode provided on each nozzle, and the nozzle 9 communicates with the mist generating section 2 on one side and faces the paper 13 on the other side. The mist generating unit 2 includes an ink container, a mist generating container surrounded by a central wall that partitions the inside of the ink container, and a mist generating vibrator fixed to the bottom of the mist generating container. It consists of a charging electrode that is disposed near the ink liquid surface and charges the ink mist as it is generated from the ink liquid surface.

Air flow 8 is generated by fan 5 in the direction of arrow 4.

It is ejected from nozzle 9. Ultrasonic waves are generated by the vibrator 3 of the ink mist generating section 2, and the charged electrode 1
Ink mist charged by 5 is generated.The generated ink mist flies from the mist inflow lower to the nozzle portion 9 on the air flow 8.

The mist unnecessary for recording is deflected by the deflection electrode 1o provided in the nozzle section, and the mist 12 that is not deflected by the one-pixel signal collected into the ink container 1 by the gutter 11 reaches the paper 13 on the airflow. recorded. At this time, if the non-deflection time Pw is long, the density of the recorded pixel will be high, and if Pw is short, the density will be low. The deflected ink mist is received by the gutter 11, and the amount of charge is detected by the charge amount detection electrode 16. The amount of charge is proportional to the number of mist, so if the amount of charge detected within a certain period of time is small, the number of mist is small. In other words, the concentration of the mist is low. When it is detected that the density of the mist is low, the above-mentioned PW is increased to correct the density to a predetermined density. If the detected amount of charge is thick, conversely shorten Pw to correct the density s P The cycle of detecting the amount of charge to determine the length of w is for each pixel signal, - for each line recording, - for each page recording. every.

Alternatively, the detection operation may be performed in hourly intervals.Also, since the nozzles are normally arranged at right angles to the direction of paper travel, the concentration of mist may be lower near the center and at both ends. A different case occurs.

Furthermore, if detailed control is attempted, the mist concentration may differ for each nozzle. To deal with this.

If the charge amount detection electrode 11 is provided for each nozzle or divided into areas such as the center and both ends, and each area is controlled, density unevenness will be further reduced and printing quality will be improved. In the above embodiment, the amount of electricity charged in the mist is detected as a means for measuring the mist concentration, but the same effect can be obtained by detecting the amount of light transmitted through the mist distribution section.

According to the above embodiment, when the power is turned on (started), the time required for the mist concentration to rise by the mist generator can be considerably shortened (if the mist concentration is generated to a certain extent, it can be corrected by Pw, (You can start printing quickly.)

Print quality can be improved by correcting density unevenness using Pw. By performing the correction in each nozzle or each area, there are advantages such as reducing density unevenness within a page.

FIG. 4 is a main part configuration diagram for explaining another embodiment of the present invention, and FIG. 5 is a flowchart for explaining the operation of the embodiment shown in FIG. Ink mist generation tank, 22 ink liquid, 23 piezo vibrator, 2
4 is the ink mist collection section.

25 is a deflection electrode, 26 is a charge amount detection electrode, 27 is a corona'#FfIt device, 28 is a charged ink mist, 29 is a nozzle, 30 is a recording paper, and in the ink mist generation tank 21, the ink liquid 22 is The ultrasonic vibration of the child 23 turns into ink mist.

At this time, if a plurality of piezo vibrators 23 are provided, the amount of mist generated can be controlled by the number of driven piezo vibrators.The generated ink mist is transferred to the corona charging device N27.
Normally, during printing, the deflection electrode is turned on and off according to the print information, and when printing on the recording paper 30, the deflection electrode is turned off and the ink mist is recorded. Sprayed paper in 30 directions.

When not printing, it is turned on and the ink mist is collected in the collection section. Here, in order to keep the ink mist amount constant, an ink mist amount detection command is issued according to a fixed rule, and the ink mist amount is detected. That is, the deflection electrode is turned on for a certain period of time to send the ink mist to the collection section 24, and the amount of electricity detected by the charge amount detection electrode 26 in the collection section during that period is taken as the amount of ink mist. If the detected amount of electricity is larger than the reference value, it is determined that the amount of ink mist is large, and the number of drives of the piezo vibrator 23 is decreased, and if it is smaller than the reference value, the number of drives is increased.The amount of ink mist is adjusted to 0 or more. is kept constant i.

FIG. 6 is a block diagram of an electric circuit suitable for application to the inkjet recording apparatus shown in FIG.
2 is a piezo vibrator driver.

43 to 45 are piezo vibrators for generating ink mist.

48 is a deflection electrode driver, 49 is a mist deflection electrode, 5
0 is an A/D converter, 51 is a charge amount detection electrode, and 40
~45 is a piezo vibration unit for generating ink mist, 4
8.49 constitutes a mist deflection unit, and 50.51 constitutes a charge amount detection unit. Now, as usual, 43 and 44
Suppose you are driving a piezo vibrator. The deflection electrode 49 is turned on for a certain period of time according to a detection instruction from the microcomputer 31, and the amount of electricity detected by the charge amount detection electrode 51 at that time is converted into a digital value by the A/D converter 50, and then sent to the microcomputer 3 via Ilo 47.
1 is fed back. Here, the microcomputer 31 compares the ° reference value in the ROM 33, and if it is larger, determines that the amount of mist is large, and stops driving the piezo vibrator 44.

If it is smaller than the reference value, the piezo vibrator 45 is driven. In this example, the amount of mist is determined by detecting the amount of charge, but in addition to this, a photo interrupter is installed in the flow path to detect changes in the amount of light due to ink mist crossing the optical path. However, the amount of mist may also be determined.

Further, in this embodiment, the number of drives of the piezo elements is changed, but the amount of mist generated may be changed by changing the drive frequency of the piezo elements. According to this embodiment,
The amount of ink mist is kept constant and stable printing quality can be obtained.

Effects As is clear from the above explanation, according to the present invention, when the power is turned on (started), the time required for the mist generator to raise the mist concentration can be shortened. Then, it can be corrected by Pw.

You can start printing quickly. ). Print quality can be improved by correcting density unevenness using Pw. By performing correction in each nozzle or each area, density unevenness within a page can be reduced. Further, there are advantages in that the amount of ink mist is kept constant and stable printing quality can be obtained.

[Brief explanation of the drawing]

1 is a side sectional view for explaining an embodiment of an inkjet recording apparatus according to the present invention, FIG. 2 is a perspective view of the entire see-through, and FIG. 3 is a flowchart for explaining the operation of the present invention. FIG. 4 is a main part configuration diagram for explaining another embodiment of the present invention, FIG. 5 is a flowchart for explaining the operation of the embodiment shown in FIG. 4, and FIG. 4 is a block diagram of an electric circuit suitable for application to the inkjet recording apparatus shown in FIG. 4. FIG. 1... Ink container, 2... Ink mist generator, 3
... Vibrator, 4... Center wall, 5... Fan, 6...
... Ink mist, 7... Ink mist inlet, 8.
... Air flow, 9... Nozzle, 10... Deflection electrode, 1
1... Gutter, 12... Printing mist, 13... Recording paper, 14... Mist return path, 15... Load @ electrode,
16... Charge amount detection electrode. 21... Ink mist generation tank, 22... Ink liquid. 23...Piezo vibrator, 24 Ink mist collection section. 25... Deflection electrode, 26... Charge amount detection electrode, 27
...Corona charging device, 28...Charged ink mist,
29... Nozzle, 30... Recording paper. Patent applicant Ricoh Co., Ltd. Figure I Figure 2 Figure 3 Figure 4 j Figure 5 [, J

Claims (6)

[Claims] (1) An inkjet recording apparatus that records ink mist on a recording medium, comprising a detection means for detecting the density of the ink mist, and modulating a pixel signal to be recorded according to a detection signal of the detection means. Inkjet recording device. (2) A charging device that charges the ink mist, and a charge amount detection means that detects the amount of charge of the charged ink mist, and the detected amount of charge is taken as the concentration of the ink mist. The inkjet recording device according to scope (1). (3) The inkjet recording apparatus according to claim (2), characterized in that the charge amount detection means is provided for each ejection port or for each predetermined range. (4) An inkjet recording device that records ink mist on a recording medium has a detection means for detecting the density of ink mist, and controls the amount of ink mist generated in accordance with the density of ink mist detected by the detection means. An inkjet recording device characterized by: (5) The detection means is a means for detecting the amount of light transmitted through the ink mist flow section.
The inkjet recording device according to item 4). (6) A charging device that charges an ink mist, and an ink mist collection means that collects the ink mist charged by the charging device, and the ink mist collection means is provided with a charge amount detection electrode, and the electrode is used to detect the ink mist. Claim (4) or (5) characterized in that
).