JPH0452218B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for determining defective printing and replenishing solvent for an inkjet recording apparatus.

[Prior art]

In recent years, inkjet recording devices have been increasingly used as computer output terminals or as devices for directly printing dates, serial numbers, etc. on products during the production process because of their ability to perform non-contact, high-speed printing.

This device supplies ink under pressure to a nozzle and applies vibrations at a constant frequency to turn the ink into particles.At this time, the particles are appropriately charged and electrically deflected. Therefore, a predetermined pattern is recorded on the recorded object.

Here, FIG. 1 is a block diagram including nozzle control of this inkjet recording apparatus. The principle of the inkjet recording apparatus will be explained below using this diagram.

When the excitation voltage generated by the excitation signal generation circuit 9 is applied to the vibrator 2 installed in the nozzle 1 according to the output signal of the fundamental wave oscillator 13, the pressurized ink in the nozzle 1 is ejected and becomes particles. . Particle formation is performed in synchronization with the excitation frequency of the vibrator 2, and when the output of the charging signal generation circuit 14 is applied to the charging electrode 4 through the amplifier 10 in accordance with this, the ink particles 3 are charged.

The charged ink particles 3 are deflected by a deflection electrode 5 connected to a high-voltage power source 11 according to the amount of charge, and reach a predetermined position on the recording material 7 .

Therefore, the vibrator 2 is constantly excited and ink particles 3 are continuously created, but the ink particles 3 that do not contribute to recording are not charged and therefore are not deflected and are collected by the gutter 6. It's summery.

Note that 8 is a charge detector, 12 is a charge amplification processing circuit, and 15 is a comparator, which will be described later.

Here, in order to print characters correctly, the ink particles 3 must be charged to the required amount, and the charging performance of the ink particles 3 depends on the printing phase, the creation status of the ink particles 3, and , which are affected by changes in the physical properties of the ink, and it is required to detect these and perform charging performance processing.

First, the printing phase described above will be explained using the charging phase explanatory diagram of FIG. 2.

A shows the excitation voltage of the vibrator 2, B shows the voltage of the charging electrode 4, and C shows the relationship between the particle formation timing and the dot miss rate.

Here, since the ink particle formation mentioned earlier is synchronized with the excitation frequency of the vibrator 2, one ink particle 3 is created in one cycle, and when the ink particle 3 is formed into particles, is charged with electricity. Therefore, it is necessary that the charging signal reaches its maximum value at the time of particle formation.

In other words, it may be rising or falling;
It is something that should not be absent or absent at all.

Further, the dot miss rate shown in C in FIG. 2 is the rate at which the ink droplets 3 do not reach a predetermined position on the recorded object 7, that is, the dot miss rate is not properly charged.
It can be seen from FIG. 2C that if particles are formed at the rise and fall of the charging voltage as shown in FIG. 2B, the dot miss rate described above becomes extremely high.

In order to normally charge the ink with the charging voltage shown in FIG. This range of Q is the effective phase of printing.

By the way, in order to always perform stable charging,
It is necessary to detect the timing of particle formation and change the phase of the charging signal accordingly.

In order to detect this particle formation timing, as shown in FIG. The output from the comparator 8 is passed through the charge amplification processing circuit 12 to the comparator 1.
5, it is compared with the reference voltage Vref, and its binary output is input to the charging signal generation circuit 14 for control.

Regarding this, its operation will be explained with reference to FIGS. 3a to 3d of phase search explanatory diagrams, which are timing relationship diagrams between the excitation signal and the search signal related to the above detection.

As shown in Figure 3a, the period T of the excitation signal is
In this example, the search signal θ ₀ is divided into 8 parts and the search signal θ 0 is divided into 8 parts.
Eight types of signals from .theta.7 to _.theta.7 are created, and each of these search signals is applied to the charging electrode 4 at regular intervals to charge the ink particles 3. Further, FIG. 3c shows the timing of ink particle formation, and it is considered that the ink is formed into particles at this timing. Furthermore, an example of a video signal (signal related to data information to be printed) corresponding to the phase of the above search signal θ ₁ is shown in FIG. 3d.

As shown by the broken line in the figure, it is assumed that the video signal begins at the rising edge of the search signal θ ₁ and ends at the next rising edge.

Each search signal is transmitted to the charge detector 8, charge amplification processing circuit 12, comparator 15,
and processed by the charging signal generation circuit 14,
Among the phases, the search signal for one layer is considered to be the optimum printing phase, and these determine the printing phase of the video signal centered on the ink droplet formation timing in Fig. 3c, and in this way, the printing phase is determined. Charging performance related to is processed.

Next, regarding the creation status of ink particles, to check the creation status of ink droplet 3, the ink creation status is stopped by a strobe synchronized with the ink creation frequency, that is, the excitation frequency, and visually observed. Alternatively, the printing situation can be detected and processed by changing the excitation voltage at regular intervals and checking the printing situation each time.

Finally, we will discuss changes in the physical properties of the ink.

That is, regarding changes in ink physical properties, the conventional method has been to define the ink life as the time during which normal printing can be guaranteed, and to replace the ink when the ink usage time becomes longer than the ink life.

However, the environments in which inkjet recording devices are used vary widely in industrial applications, and in very low temperatures, the solvent components of the ink evaporate significantly, causing changes in the physical properties of the ink before the ink reaches the end of its life, and charging performance deteriorates. A phenomenon occurs in which the paper falls off and normal printing is not possible.

On the other hand, since there has been no way to easily describe changes in ink physical properties, first,
The current method has been to check the state of particle production by adjusting the excitation voltage, and if the defective print still cannot be repaired, the ink is replaced.

In other words, even in cases where repairs could be made by simply replenishing the solvent components, there was no way to check that.
This was extremely uneconomical as the entire amount of ink had to be replaced.

In addition, if a defective print occurs before the ink's lifespan, even if the cause is due to a change in the physical properties of the ink, there is no way to clearly check it on site, so first of all,
This was a very inefficient maintenance process in which the circulation system parts were cleaned and replaced, the control system parts were checked and replaced, and then the ink was replaced.

In other words, if charging performance deteriorates and defective printing occurs, the cause may be a change in the physical properties of the ink, a circulatory system such as circulatory system parts, or a problem with the control system such as control system parts. This had the disadvantage that it was not possible to sort and determine whether it was present or not.

[Purpose of the invention]

The purpose of the present invention is to be able to easily distinguish and detect changes in the physical properties of ink, and to determine whether the cause of defective printing is due to the physical properties of the ink or to the circulation system such as other circulation parts or the control system such as control parts. This can greatly improve the efficiency of maintenance work, and when there is a change in the physical properties of the ink,
It is economical as it repairs defective prints by adding solvent without replacing the entire amount of ink, and it is particularly effective in improving ink life in harsh environments where humidity is extremely low and the ink solvent component evaporates significantly. An object of the present invention is to provide a method for determining defective printing and replenishing solvent for an injection recording device.

[Summary of the invention]

The present invention provides a binary signal used to change the charging phase in accordance with detection of the timing of particle formation when the ink particles formed by an excitation voltage are charged and printed. A main control device into which information from the character generator, printed character information, information on the presence or absence of phase shift printing, etc. is input, and this main control device processes the binarized signal and determines the timing of ink particle formation. Characters output by the main control device in response to the input of the phase synchronization circuit into which printing phase information is input from the main control device, the information from the character generator, the print character information, and the presence/absence information of print phase shift printing. There is a character data latch into which data is input and whose output timing is controlled by the phase synchronization circuit to control the charging phase, and an analog converted value of the output value of this character data latch is amplified to generate ink particles. The charging performance detection control device includes a charging performance detection control device including an amplifier configured to perform charging, and in a printing phase shift mode based on a printing charging signal, a main control device of the charging performance detection control device detects a normal printing phase number, Check whether this number of normal printing phases is the same as the number of normal printing phases when the ink physical properties are normal, and replenish the solvent if the number of normal printing phases checked as described above is lower than when the ink physical properties are normal. It is characterized by:

[Embodiments of the invention]

An embodiment of the inkjet recording method according to the present invention will be described with reference to FIGS. 4 to 7 in conjunction with FIGS. 1 to 3 mentioned above.

Here, FIG. 4 is a block diagram of a charging performance detection and control device suitable for implementing the method of the present invention.

Therefore, in FIG. 4, instead of the charge detector 8, amplifier 10, charge amplification processing circuit 12, charge signal generation circuit 14, and comparator 15 in the inkjet recording apparatus shown in FIG. A charging performance detection control device is provided, and the charge detector 21, charge amplification distance circuit 22, comparator 23, and amplifier 32 of this device are the same as the charge detector 8, charge amplification processing circuit 12, and comparator 32 described above. This is equivalent to the amplifier 15 and the amplifier 10.

That is, the search signal shown in FIG. 3b is detected by the charge detector 21, the small signal thereof is amplified by the charge amplification processing circuit 22, and the comparator 23 converts it into a binary signal. This binarized search signal is processed by the main controller 24, the ink droplet formation timing is determined, and the printing phase information is given to the phase synchronization circuit 29.

On the other hand, the printed character information and phase shift printing presence/absence information are input from the panel input section 27, and the inputs are transmitted to the main control device 24 through the panel input/output I/F (interface) 26, and are also transmitted to the panel display section. 28.

The contents of a character generator for printing are stored in a storage device 25, and in response to panel input, the main controller 24
Character data is output to character data latch 30.
The charging phase is controlled by controlling the output timing of the character data latch 30 by the phase synchronization circuit 29, and the digital output value of the character data latch 30 is converted into an analog value by the D/A converter 31. The ink particles are amplified by an amplifier 32 and charged.

The above configuration is used for charging performance detection control.Next, the flow of the charging performance detection control method including the use of the above-mentioned charging performance detection control device will be explained in the fifth section. This will be explained with reference to the flowchart shown in the figure.

First, in the normal printing mode, it is visually checked whether printing is being performed normally. ...Block 40.

If printing is not performed normally, the excitation voltage related to the excitation signal of the excitation signal generation circuit 9 is adjusted.
...Block 41.

After adjustment, check whether printing is normal. ...Block 42.

If the printing is not normal, the panel input section 27
By operating the switch, the main controller 24 is set to the print phase shift mode, as shown in FIG. 6, which will be described later, using the built-in program, and performs print phase shift printing processing and print check. ...Block 43.

Check the number of normal printing phases among those printed with eight phases. ...Block 44.

It is checked whether the number of normal printing phases checked in block 44 is the same as the number of normal printing phases when the physical properties of the ink are normal, that is, when the ink is normal. ...Block 45.

At block 45, if the number of normal printing phases checked at block 44 is lower than when the physical properties of the ink are normal, the solvent is replenished. ...Block 46.

At block 45, if the number of normal printing phases checked at block 44 is the same as when the physical properties of the ink are normal, then at block 47, the cause of the defective printing is not due to changes in the physical properties of the ink, but due to the circulation of other circulation system parts. In this way, by using the above-mentioned charging performance detection control device, it is possible to distinguish between changes in the physical properties of ink and other changes. It is something that can be determined.

Next, the above-mentioned printing phase shift printing process performed when printing is not normal will be explained.

That is, FIG. 6 is a flowchart showing the flow of block 43 related to the printing phase shift printing process described in FIG. 5 in the control device 24 shown in FIG. 4, and is automatically performed by a program. It is something.

In block 50 of the printing mode, it is determined whether or not the printing phase shift printing process is necessary based on the information from the panel input section 27 in FIG. That is, the determination is made based on information obtained by turning on a switch related to print phase shift printing processing in the panel input section 27. ...Block 51.

If a printing phase shift printing process is required, the printing phase search process is performed using the search signal related to the eight phases b shown in FIG. ...Block 52.

As a result of the phase search, the printing phase is determined. ...Block 53.

The best printing phase according to the particle formation timing, that is, the normal printing phase is displayed on the panel. ...Block 54.

Next, the printing phase to be printed now is displayed on the panel. ...Block 55.

Performs printing process. ...Block 56.

Shifts the printing phase by one phase.

Here, the seventh part of the printing phase shift printing process explanatory diagram
The figure shows the relationship between the excitation signal a, the corresponding ink droplet formation timing c, and the eight-phase video signal (phases θ ₀ to θ ₇ ) e. In block 52 of the phase search process shown in FIG. 6, if the printing phase corresponding to the particle formation timing is the phase θ ₁ of the video signal e, if it is shifted by one phase from this,
The printing phase is θ ₂ . ...Block 57.

It is determined whether there has been a shift by 8 phases from θ ₀ to θ ₇ , that is, whether the angle has shifted. If eight phases have not been completed, the process returns to block 55 and displays the printing phase shifted by one phase. ...Block 58.

If the printing phase shift printing process is not performed in the previous block 51, the process returns to the normal printing process. ...Block 59.

As described above, in this embodiment, since the charging performance detection process is performed using the circuit used for printing phase search, charging performance can be detected simply by adding a program. be.

That is, the main control device 24 is, for example, a microcomputer, and has a ROM in its configuration that incorporates the above-mentioned sequential program, and is a main control device in a charging phase detection control device used for normal printing phase detection. The structure of the device was modified to the above-described structure, and the overall structure including this was made into the charging performance detection control device shown in FIG.

Therefore, although the above embodiment relates to 8 phases, that is, an angle transition of 45 degrees, it may be an arbitrary re-transition, for example, 6 phases or 10 phases. If it is an angular shift, precise detection can be performed, but in relation to charging phase detection, it is usually preferable to use an eight-phase detection method.

〔Effect of the invention〕

As described above, according to the present invention, changes in ink physical properties can be easily distinguished and detected, so it is possible to determine whether the cause of defective printing is due to the ink physical properties or to the circulation system such as other circulation parts or the control system such as control parts. It is possible to perform sorting discrimination, greatly improving the efficiency of maintenance work.

In addition, if there is a change in the physical properties of the ink, it is possible to repair defective printing by adding a solvent without replacing the entire amount of ink, making it economical. The effect of improving ink life under environmental conditions is significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram including nozzle control of an inkjet recording apparatus, FIG. 2 is a diagram explaining its charging phase, FIG. 3 is a diagram explaining its phase search, and FIG. 4 is an implementation of the method of the present invention. FIG. 5 is a flowchart showing the flow of charging performance detection control including the use of the charging performance detection and control device of FIG. 4, and FIG. 6 is a block diagram of a charging performance detection control device suitable for use in FIG. 7, a flowchart diagram related to the printing phase shift printing process, is an explanatory diagram of the printing phase shift printing process. DESCRIPTION OF SYMBOLS 1... Nozzle, 2... Vibrator, 4... Charging electrode, 5... Deflection electrode, 9... Excitation signal generation circuit,
11...High voltage power supply, 13...Fundamental wave generation oscillator,
21...Charge detector, 22...Charge amplification processing circuit, 23...Comparator, 24...Main controller, 25
... Storage device, 26 ... Panel output I/F, 27
...Panel input section, 28...Panel display section, 29
...Phase synchronization circuit, 30...Character data latch,
31...D/A converter, 32...amplifier.

Claims (1)

[Claims] 1. A binary signal used to change the charging phase in response to detection of the timing of particle formation when the ink particles formed by the excitation voltage are charged and printed, and a character generator for printing. a main control device into which information from the computer, printed character information, information on the presence or absence of printing phase shift printing, etc. are input, and the main control device processes the binarized signal,
The phase synchronization circuit receives the printing phase information that determines the ink dropletization timing from the main controller, and in response to the input of information from the character generator, printing character information, and printing phase shift printing presence/absence information. a character data latch into which character data output by the main controller is input, and whose output timing is controlled by the phase synchronization circuit to control the charging phase;
The charging performance detection control device includes an amplifier that amplifies the analog-converted output value of the character data latch to charge the ink particles. The main control device of the performance detection control device detects the number of normal printing phases and checks whether this number of normal printing phases is the same as the number of normal printing phases when the ink physical properties are normal. A method for determining defective printing and replenishing solvent for an inkjet recording device, characterized by replenishing a solvent when the number of printing phases is lower than when the ink physical properties are normal.