JPH03169642A - Inkjet recording apparatus - Google Patents

Abstract

PURPOSE:To obtain a detecting means of the ink with high reliability by judging the presence or absence of the ink within an ink tank from a resonance frequency detected by a vibration detecting means when the ink tank is vibrated by a vibration generating means. CONSTITUTION:A constant f1, is given as the vibrating frequency (f) of a vibration generating body 9. The vibration generating body 9 vibrates with the frequency (f). The constant f1 is the lowest limit when the covering range of the distribution of the resonance frequency of an ink tank 22 which is found to be changed in accordance with the remaining amount of the ink is from a frequency f1 to a frequency f2. It is detected from the amplitude of a vibration sensor 10 whether the frequency (f) is a resonating point. If the frequency (f) is not the resonating point, a serration value DELTAf is added to the frequency (f) to raise the frequency. Then, the process enters a loop to return to a step 52. The serration value DELTAf is a constant obtained by dividing between the frequencies f1 and f2 into (n), n being an integer determined suitably from experiments. If the frequency (f) is detected to be the resonating point, it is checked whether the frequency (f) is equal to a proper frequency f2 determined beforehand from experiments to show the absence of the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device that performs printing by ejecting ink from a recording head to form an image on a printing paper.

[Conventional technology]

In conventional inkjet recording devices, two needle-shaped electrodes are embedded in the ink tank that stores ink, and the resistance value between the two electrodes is measured using the conductivity of the ink. Some printers have detection means for detecting the presence or absence of ink.

(Problems to be Solved by the Invention) The ink detection means in the conventional inkjet recording apparatus described above has the problem of low reliability because the electric chair is easily corroded and the amount of change in the detection resistance value cannot be large. there were.

The object of the present invention is a highly reliable ink detection means.

[Means to solve the problem]

The inkjet printer of the present invention is an inkjet recording device that performs printing by ejecting ink from a recording head to form an image on printing paper, and includes a vibration generation-F stage and vibration detection means in an ink tank that stores ink. When the ink tank is vibrated by the vibration generating means, the resonance frequency detected by the vibration detection means causes the ink in the ink tank to
A discriminating means for discriminating y-absence was provided.

The recording head is equipped with a thermal energy generating element as an ejection energy generator that generates thermal energy used to eject ink, and utilizes a sudden change in /E force caused by bubbles generated by the thermal energy. There is something that makes ink come true by doing.

(Function) When the ink tank is vibrated by the vibration generating means, the resonant frequency of the ink tank differs depending on whether there is ink in the ink tank or not, so the frequency detected by the vibration detecting means also differs. Based on this difference in frequency, the determining means determines the presence or absence of ink.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the inkjet recording apparatus of the present invention, FIG. 2(a) is a partially cutaway view showing the carrier included in the embodiment of FIG. FIG. 2(b) is a partially cutaway view showing a state in which the recording head is attached to the carrier shown in FIG. 2(a).

The carrier 1 is provided with a pair of elastic holding claws 7 on the left and right sides, and the holding claws 7 press down and hold the upper surface of the removable recording head 2 which is attached to the carrier 1. Printing is performed by moving the recording head 2 along the platen 3 at a constant speed and ejecting ink at a timing corresponding to the speed to form an image on the printing paper 4.

The carrier 1 is provided with two levers 11 and 12, as shown in FIGS. 2(a) and 2(b), and each lever 11.
．． 12 are 101 moving axes 13 and 14 in the direction perpendicular to the paper surface, respectively.
It is pivoted freely around the center of rotation. Lever 1
A vibration generator 9 (described later) is attached to the upper end of the lever 12, and a vibration sensor 10 (described later) is attached to the upper end of the lever 12. The lower end of each lever 11.12 is connected by a tension spring 15, and when the recording head 2 is not mounted on the carrier 1, each rotation shaft i3 supporting each lever 11.12 , 14 in the opposite direction, so that the vibration generator 9 and the vibration sensor 10 each protrude from the contact surface II of the carrier 1, as shown in FIG. 2(a). There is. - On the other hand, when the recording head 2 is attached to the carrier 1, the vibration generator 9
The vibration sensor 10 is lowered against the force of the spring 15, as shown in FIG. 2(b), and is brought into close contact with the f-plane of the recording head 2 with a constant pressure.

The vibration generator 9 is, for example, a Viezo element, which generates mechanical displacement when a voltage is applied thereto, and generates mechanical vibration as a vibration generating means by applying a human voltage signal having a vibration waveform. do. The vibration sensor 10 is a device such as a strain gauge that can obtain a change in electrical output due to a change in electrical characteristics when subjected to mechanical displacement, and serves as a vibration detection means to sense mechanical vibration and generate an electrical signal in the form of a vibration waveform. Output.

FIG. 3(a) is a side view of the recording head 2, and FIG. 3(b) is a side view of the recording head 2.
) is a sectional view taken along line E-E in FIG. 3(a).

The recording head 2 is equipped with a nozzle system 2I and an ink tank 2F, and a nozzle (not shown) that discharges ink in the direction of arrow D is installed at regular intervals in the discharge head 23 of the nozzle system 2.
There are rows of rows. The nozzle system 2. is equipped with a thermal energy generating element (not shown) as an ejection energy generating body that is equipped with an electronic circuit (not shown) and generates thermal energy, and uses a sudden pressure change caused by bubbles generated by the thermal energy to ink. Exhale. Inside the ink tank 22, an absorber (not shown) for impregnating and storing ink is housed. These nozzle system 21 and ink tank 22 are communicated through a tube (not shown), and when printing, ink is supplied from ink tank 22 to ink tank 2I.

Next, the control system of the embodiment shown in FIGS. 1 to 3(a) and (b) will be described with reference to FIG. 4.

Central processing circuit 44 (hereinafter referred to as CPU 44) is the determining means.
) includes a character generator ROM 41 that stores dot images or pattern images for printing;
Program ROM 4 that stores the block diagram of the entire operation
2 and a working RAM 43 are connected. Printed information 46 is manually inputted to the boat 45 by an input means such as a key port or an external circuit (not shown), and this printed information 46 is manually inputted to the CPU 44 via the boat 45 . A dot image or a pattern image that matches the print information 46 input to the CPU 44 is read out from the character generator ROM 41 and stored in the program ROM 4.
The recording head 2 and the vibration generator 9 are controlled via the driver 47 according to commands from the CPU 44 that are output according to microinstructions stored in advance in the recording head 2 and the vibration generator 9.
and other drive sources 48. Further, the CPU 44 inputs information from the vibration sensor 10 and sensors (not shown) via the port 45, and performs various controls according to the input information.

Next, the operation of the embodiment shown in FIGS. 1 to 4 will be explained with reference to FIG. 5.

First, a constant f1 is set as the frequency f of the vibration of the vibration generator 9 (step 51), and the vibration generator 9 is caused to vibrate at the frequency f (step 52). Here, the constant f, is the lower limit when the range that covers the distribution of the resonant frequency of the ink tank 22, which changes depending on the remaining amount of ink, is the frequency f, -f2 by examining the characteristics of the ink tank (not shown) in advance. value. That is, the resonance frequency is set to the resonance frequency when the ink tank 2 is filled with ink to the maximum extent. Next, it is determined from the amplitude of the vibration sensor 10 whether the frequency f is a resonance point or not (step 53), and if it is not a resonance point, a step value △f is added to the frequency f to increase the frequency, and the loop returns to step 52. enter. Here, the step value Δf is a constant obtained by dividing the frequency f, -f, into n in advance, and n is an integer appropriately determined by experiment. When it is determined that it is the resonance point, it is determined whether the frequency f at this time is equal to the natural frequency f2 without ink determined in advance in an experiment (step 55), and if it is equal, there is no ink, and if it is not equal, there is ink. (steps 56 and 57). When it is determined that there is no ink in step 56, a message indicating that there is no ink is displayed, an alarm is issued, or the printing operation is stopped.

Figure 6 shows the vibration sensor 10 when vibration is applied from the vibration generator 9 by changing the frequency f.
FIG. 3 is a diagram showing the amplitude of the output voltage of FIG.

When the ink tank 22 is filled with ink to the maximum, a curve 61 having the maximum amplitude at frequency f1 is obtained,
When the ink tank 22 is empty, that is, when there is no ink, a curve 62 having the maximum amplitude at frequency f2 is obtained.

The ink tank 22 resonates at a frequency that has the maximum amplitude.

It is preferable that the frequency f and %f2 used in this embodiment be in the ultrasonic band so as not to be sensed by the user, and it is preferable to determine the material, capacity, structure, etc. of the ink tank 22 from this point of view.

In the above-mentioned embodiments, the vibration generating body and the vibration sensor are pressed against the outer wall of the ink tank with a constant force, or they are installed on the inner wall, or embedded in the wall, and only the electric contact point is connected to the ink tank. It is also possible to have a configuration in which it is provided outside to control human output.

(Effects of the Invention) As explained above, the present invention applies vibration to an ink tank and determines the presence or absence of ink in the ink tank based on the resonance frequency. This has the effect of making it possible to realize an inkjet recording apparatus equipped with a highly reliable and simple ink detection means that is unnecessary and has no fear of corrosion.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the inkjet recording apparatus of the present invention, FIG. 2(a) is a partially cutaway view showing the carrier included in the embodiment of FIG. Figure 2(b) is a partially cutaway view showing the recording head mounted on the carrier shown in Figure 2(a), Figure 3(a) is a side view of the recording head, and Figure 3(b) is a side view of the recording head. E in Figure 3<a)
-E line sectional view, Fig. 4 is Fig. 1 to Fig. 3 (a), (
FIG. 5 is a flowchart showing the operation of the embodiment shown in FIGS. 1 to 4, and FIG. 6 is a block diagram showing the control system of the embodiment shown in b). FIG. FIG. 4 is a diagram showing the amplitude of the output voltage of the vibration sensor when the vibration sensor is applied. 1...Carrier, 11...Contact surface, 2...3 Self-recording head, 21...
... Nozzle system, 22 ... Ink tank, 23
...Discharge surface, 3...Platen,
4... Print paper, 7... Holding claw, 9... Vibration generator, 10.
...Vibration sensor 11.12...Lever 1
:l, +4...Rotation axis, l5...
...Tension spring, 4l...Character generator ROM, 42...Program ROM, 43...RAM. 44...
...CPU, 45...Port, 46
...... Print information, 47... Driver, 48... Other drive source, 5l~
57...Step, 61.62...Curve.

Claims (1)

[Claims] 1. In an inkjet recording device that performs printing by ejecting ink from a recording head to form an image on printing paper, an ink tank that stores ink is provided with vibration generation means and vibration detection means. An inkjet recording apparatus characterized in that the inkjet recording apparatus is provided with a determining means for determining whether or not there is ink in the ink tank based on a resonance frequency detected by the vibration detecting means when the ink tank is fixed and vibrated by the vibration generating means. . 2. The recording head is equipped with a thermal energy generating element as an ejection energy generator that generates thermal energy used to eject ink, and utilizes rapid pressure changes caused by bubbles generated by the thermal energy. Claim 1 characterized in that the ink is ejected by
The inkjet recording device described in .