JP3165706B2 - INK JET RECORDING METHOD AND INK JET RECORDING APPARATUS USING THE METHOD - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus used as an output of an information processing apparatus and an ink jet recording apparatus which is a printer integrated with the information processing apparatus.
The present invention relates to a recording device such as a copying machine and a facsimile. The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink in accordance with an image information signal, using an electrothermal converter as an energy generator that generates energy used for ejecting ink.

[0002]

2. Description of the Related Art A basic invention in which a rapid state change is caused by the heat energy of an electrothermal transducer to form a bubble and discharge a droplet is disclosed in US Pat. No. 4,723,1.
29. In the present invention,
A simultaneous driving method of simultaneously driving each converter as a driving condition of a plurality of electrothermal converters, a non-simultaneous driving method of sequentially driving a drive pulse to be applied to each converter with a phase difference for oblique lattice recording, Is added. A similar description is also disclosed in JP-A-55-109672.

Further, US Pat. No. 4,723,129 discloses an invention in which a so-called time-division driving method is applied to a large number of electrothermal converters.

However, in a recording apparatus using thermal energy which has been put to practical use in the past, the above-described simultaneous driving method has been regarded as practically preferable in order to take advantage of high-speed recording.

For this reason, most of the inventions of the ink jet recording apparatus provided with a plurality of electrothermal transducers are exclusively based on the premise that drive electric signals corresponding to recording signals are simultaneously supplied to each transducer. .

Conventionally, this type of technology is disclosed in, for example,
There is a liquid jet recording method disclosed in Japanese Patent Publication No. 109672, which is characterized in that a phase difference occurs between recording droplets ejected from at least adjacent orifices.

[0007] One advantage of the above-mentioned conventional example is that the driving current at the time of multi-ejection is reduced, and the voltage drop due to wiring resistance is reduced. However, this method
Return of the ink meniscus after ejection during minority present discharge in it takes place in a short time, has a drawback that a large number at the discharge becomes significantly slower. For example, the meniscus return frequency at the time of discharging a small number of pieces is 9 KHz, but drops to 5 KHz at the time of discharging many pieces. Therefore, a low repetition frequency at which a large number of ejections can be performed is set as the upper limit of the driving frequency of the apparatus.

[0008]

The limitation of the drive frequency of the entire apparatus to the meniscus return time at the time of multi-ejection is a major problem to be solved in the printer field where higher speed recording is desired. It is one of.

SUMMARY OF THE INVENTION The prior art, the ink temperature of the large number of discharge time for the refill phenomenon that the frequency is slow due that thermal problems energizing the large number (i.e. motor near the aforementioned increase, viscosity layer This phenomenon has been considered to be a phenomenon in which the amount of ejected ink increases due to the decrease and the amount of meniscus receding also increases, so that refilling takes a long time.

However, the present inventor has observed various phenomena at the time of multiple discharges in detail and conducted various experiments. As a result, due to the pause time between each group of the time-division driving, the discharge repeated at the time of multiple discharges was performed. It has been found that the frequency can be greatly improved.

The present invention is based on new knowledge different from the conventional technical point of view, and can improve the frequency of droplet formation, and can improve the landing accuracy of recording droplets on a recording material. An object of the present invention is to provide an ink jet recording apparatus and method.

The present invention is directed to an ink jet recording method and an ink jet recording method capable of achieving excellent recording while maintaining high responsiveness by focusing on bubbles formed by thermal energy.
A recording device is provided .

The ink jet recording method of the present invention employs heat
Energy is generated and bubbles are generated in the ink,
And a plurality of electrothermal converters for discharging heat
Pulse signal to be applied to the recording data and the control signal.
Ink jet recording head provided with drive element for controlling
Using, the plurality of electrothermal converters are divided into a plurality of groups,
Applying the pulse signal sequentially to each group of electrothermal transducers
Ink jet recording method that discharges ink
Applying a pulse signal to a group of electrothermal transducers
When the size of the bubble generated at
Between the time of defoaming and the next driven group of electricity
Characterized by starting application of pulse signals to the heat converter
This is an inkjet recording method.

Further , the ink jet recording apparatus of the present invention
Generates thermal energy and creates bubbles in the ink.
And a plurality of electrothermal transducers for discharging ink,
The pulse signal given to the heat converter is converted into recording data and control signal
Ink jet recording device having a driving element controlled based on the
Recording head and ink ejected from this recording head
The recording material on which an image is formed by attaching
Transport means for transporting to a recording position facing the
The plurality of electrothermal converters are divided into a plurality of groups,
The pulse signal is sequentially applied to the heat transducers for each group, and ink is applied.
In an ink jet recording apparatus that discharges
Gas generated by applying a pulse signal to the electrothermal transducer
The point at which the bubble size reaches its maximum and the point at which this bubble disappears
Between the next group of electrothermal transducers driven
It has a control means for starting application of a pulse signal.
This is an inkjet recording apparatus.

According to the present invention, the quality of printing is improved by improving the frequency of printable recording droplets and reducing the deviation of the landing positions of the recording droplets on the recording medium. It is.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 8 is a perspective view showing an ink jet recording head to which the present invention can be applied. In the figure, reference numeral 11 denotes a heat-generating portion of an electrothermal converter (hereinafter also referred to as a heat-generating element) which generates heat in response to energization and causes foaming of ink to generate thermal energy used for discharging recording liquid. It is. Reference numeral 12 denotes a substrate, and the heating element 11 is formed on the substrate 12 through a manufacturing process similar to a semiconductor manufacturing process. Reference numeral 13 denotes a recording liquid discharge port (hereinafter, also referred to as an orifice), and reference numeral 14 denotes an ink path (hereinafter, also referred to as a nozzle) communicating with the discharge port 13. Reference numeral 15 denotes an ink path forming member for forming the discharge port 13 and the ink path 14.

Reference numeral 16 denotes a top plate. Reference numeral 17 denotes an ink chamber serving as a common liquid chamber commonly communicating with the ink path 14, and stores ink supplied from an ink supply source (not shown).

FIG. 3 is a block diagram showing an example of a drive control system for the ink jet recording head having the configuration shown in FIG. Reference numeral 21 denotes a head drive circuit according to the present invention, which includes a head drive power supply 22, a timing generation circuit 23,
A print data division generation circuit 24 and a print data / drive timing generation circuit 25 are provided. Here, the timing generation circuit 23 generates the pulse width setting signal EN according to the recording data and the control signals C ₁ and C ₂ of the drive timing generation circuit 25.
B, a selection signal SEL for selecting a latch position of input print data and selecting an electrothermal transducer to be driven
1 to SEL4 and a latch signal LAT2, and the print data division and generation circuit 24 extracts and re-divides the print data for one line and supplies it to the print head drive IC 26.

FIG. 4 is a diagram showing the drive timing according to the embodiment of the present invention. The recording data SI1 for one line composed of the same number of bits as the electrothermal transducer is re-injected into the recording data SI2 corresponding to the electrothermal transducer simultaneously driven by the recording data division generating circuit, Will be transferred. Then, SEL1 is input by input of the latch signal LAT2.
SEL4 is read into the latch circuit in the drive IC selected by SEL4. Thereafter, power is supplied to the electrothermal transducer selected by the input of the ENB signal. The input of the data transfer, selection signal, and pulse width setting signal is repeated a predetermined number of times, and printing for one line is performed.

FIG. 2 shows the driving order of each nozzle in this embodiment. In the figure, reference numeral 41 denotes an ink jet recording head, and reference numeral 42 denotes recording droplets. In the figure, each nozzle in the ink jet recording head is divided into four groups, and as shown in the driving pulse in the figure, No. 1, No. 2, No. 3, No. The electrothermal transducers belonging to each group are sequentially driven with a time difference of Td in the order of 4.

FIG. 1 shows the correspondence between the drive pulse time difference Td (horizontal axis) of the electrothermal transducers divided into groups and the average response frequency of each nozzle (vertical axis (measured at all ejections)). Is shown. As can be seen from the figure , looking at the change in the response frequency corresponding to Td, the response frequency becomes substantially maximum in the range from the time of the maximum foaming of the bubble until the bubble contracts and disappears (defoams).
From this, in the range from the time when the bubble size becomes maximum to the time when the bubble disappears, the response frequency of each nozzle can be improved by subsequently applying an energizing pulse to the group of electrothermal transducers.

[0023] In this embodiment, as can be seen in FIG. 1, the driving pulse width 3 [mu] s, even up to the bubble point When 7μs Ru depend driving pulse also applied defoaming time. Focusing on the state of formation of air bubbles, from antifoaming time when performing sequential driving
When the next group is driven later, reciprocating vibration of the meniscus occurs in the discharged liquid path, which has an effect on the adjacent liquid path. Therefore, when the ink flow generated in and around the liquid path from the time of the maximum bubble to the time of the bubble disappearance is only in a certain direction, driving the next liquid path that is sequentially driven next greatly reduces unstable factors. It can be considered that the response frequency is increased because it is possible, and the ejection state can be further stabilized.

The present inventor further examined the conditions within the above-mentioned conditions, and determined the superiority and the superiority within the above-mentioned preferable range (although both are better than the conventional ones).

Even within the above preferred range, if Td is further increased, the response frequency is relatively lowered, and the landing position of the recording liquid droplet on the recording medium is slightly shifted. The printing quality is relatively deteriorated. In the experiment of the present inventor, when printing was performed at 6.5 KHz with a pulse width of 3 μs and 16 nozzles in each of 4 groups using a head of 360 DPI 64 nozzles, when the Td exceeded 20 μs, a part of the landing reference position deviation was observed. Slightly found. When Td exceeded 25 μs, the deviation started to be noticeable, but it was judged to be acceptable.

Therefore, Td is 25 μs or less, more optimally.
Is preferably 20 μs or less for the present invention.
No. In this case, it goes without saying that the upper limit is the point of time when the maximum bubble is formed in another preceding liquid path.

Further, when the discharge state of the liquid droplets was examined more minutely, it was found that the state in which the liquid wets around the discharge port cannot be completely eliminated in the process in which the liquid pops out of the discharge port in a columnar shape due to foaming. found. However, the wetting was extremely slight as compared with the conventional case. The wetting is relatively small after about 4 μs from the maximum foaming, and particularly small after 10 μs. On the other hand, it was relatively large before the lapse of approximately 4 μs. This is because, in the experiment of the present inventor, when the energization is started to the next succeeding group at the time when approximately 4 μs or more has not elapsed since the maximum foaming, the wetness around the group discharge port to be energized first remains and the energization is performed later This was a phenomenon that slightly affected the ejection direction of the group, and was partially observed.

From the above, in order to keep the ejection repetition frequency high even during multiple ejections, it is preferable to start energizing the next group in the period between the time of maximum foaming and the time of defoaming.
More preferably, the maximum foaming time is 4 μs (more preferably 10 μs).
s) It is preferable to start energizing the next group in the period between the passing time and the defoaming time.

Instead of the driving method shown in FIG. 2, a driving pulse is applied to the electrothermal converter in the order of 1, 3, 2, and 4, or as shown in FIG. Even when a drive pulse is applied to the body, between the time when the bubble is maximally foamed and the time when the bubble disappears, by starting to apply an energizing pulse to the next group of electrothermal transducers, the nozzle of each nozzle is started. The response frequency can be improved.

As described above, in the present embodiment, a plurality of electrothermal transducers are divided into n groups, and the electrothermal transducers in each section are successively energized to foam and eject droplets. In the method, between the time when the size of the bubble formed by the foaming becomes substantially maximum and the time when the bubble disappears, an energizing pulse is started to be applied to the next group of electrothermal transducers, With the above implementation, the following effects can be realized.

1) The frequency at which recording droplets can be ejected when each nozzle ejects simultaneously is greatly improved, and the recording speed can be improved.

2) It is possible to remove the adverse effect on the landing point accuracy due to the great amount of wetness as in the related art around the discharge port of the adjacent nozzle, thereby improving the print quality.

Preferred conditions for the above invention are described below. Here, a description will be given with reference to FIGS.

Here, the main part of the embodiment of the present invention will be described with reference to FIGS. 6 (a), 6 (b) and 7. FIG.

In the figure, reference numeral 41 denotes an ink jet recording head, and reference numeral 42 denotes a flight path of a recording liquid droplet. In the figure, each nozzle in the ink jet recording head is divided into four groups, and as shown in the drive pulse in FIG. The electrothermal converters belonging to each group are sequentially driven by the heating elements of the liquid paths 1, 2, 4, and 3 with a time difference of Td.

The numbers in parentheses in FIG. 7 indicate the order of driving in the group after four continuous orders among a large number of electrothermal converters are grouped into one group. . In the figure, the second electrothermal converter is driven next to the first electrothermal converter (pulse-to-pulse Td), and then the fourth converter is driven at the same timing, and the third electrothermal converter is driven. The fourth transducer is driven fourth. Therefore, the adjacent converters of each group are not driven at the same time.

FIG. 6B is a sectional view (discharge port <liquid path) showing the ink path and the plane of the heating element 11 in the ink jet recording head according to the present invention. In the figure, the area of the heating element is 133 × 28.5 = 3790.
A 5 [mu] m ^2, the distance la from the end portion of the discharge direction of the heat generating element to the orifice is 120 [mu] m. This head is a so-called edge-shater type head, but if the distance la is determined including the case where the flow path is bent, the discharge port 13
And the shortest distance between the heating element 11 and the heating element 11. From the end of the heating element in the anti-ejection direction to the end of the ink path in the anti-ejection direction (supply port 1)
The distance up to 3A) (hereinafter referred to as 1b) greatly affects the frequency at which recording droplets can be formed, that is, the printing speed as a result.

The distance 1b is the shortest distance between the supply port 13A and the heating element 11. Here, the contents examined for the distance 1b will be described with reference to FIG.

FIG. 5 is a graph showing the correspondence between the meniscus return frequency fr (refill frequency) and 1b when all nozzles are simultaneously ejected. At the time of split drive indicated by the solid line in the figure,
The drive pulse time difference Td is 13 μs, and the behavior change of fr when the heating elements of FIG. 1 are sequentially driven as they are in the arrangement order is shown. The dotted line in the figure indicates Td = 0, that is, the behavior change of fr in the non-division simultaneous drive. Show.

It can be seen from the drawing that fr is improved by shortening 1b, and fr is sharply increased particularly in the region of 1b ≦ 110 μm. Furthermore, Td = 13μ compared to simultaneous driving
Fr can be sharply increased by the divided drive which is s. This is due to the crosstalk between the nozzles. The nozzle having a shorter 1b, that is, the nozzle having a stronger influence of the crosstalk, has a higher rate of increase of fr due to the divisional driving.

In the curve A, the point A1 is 70 μm;
3KHz, A2 point is 90μm, 5KHz, A3 is 110
μm and 4.35 KHz. This tendency is shown in FIG.
(A), the same applies to the driving order in FIG.

As described above, in the ink jet recording head in which the adjacent nozzles are divided and driven, fr is improved by the divided driving, and fr is further increased sharply by setting 1b ≦ 110 μm, so that the recording speed is remarkably improved. You can see it.

More preferably, the distance lb is preferably 70 μm or less since the frequency of simultaneous driving can be exceeded. In this case, the distance 1a is optimally 120 μm.

Next, the distance 1a will be described.

The value of 1a has an appropriate value as described above. When the value of 1a becomes extremely shorter than 130 μm, Reaches the external gas uptake impossible discharging into the nozzle by a bubble is becoming defoaming during meniscus retraction after the discharging of recording liquid droplets and a meniscus contacts. This phenomenon occurs within 25 to 35 μs from the application of the ejection pulse. 2. When the bubble expands to the maximum, the tip of the bubble in the discharge direction penetrates through the orifice, so that external gas is taken into the nozzle and discharge becomes impossible. This phenomenon occurs between 5 and 15 μs after the application of the ejection pulse. Due to these two phenomena, printing failure occurs due to non-ejection of recording droplets. This phenomenon occurs remarkably in the region of 1a <90 μm, and a value of 1a ≧ 110 μm is preferable.

If the value of 1a becomes extremely longer than 130 μm, By increasing the fluid impedance from the center of the heater in the ejection direction, the ejection speed of the recording liquid drops, thereby lowering the landing point accuracy on the recording medium and deteriorating the image quality of the recorded image. 2. When the fluid impedance in the ejection direction from the center of the heater increases, the ejection amount of the recording liquid drops, so that the print density on the recording medium decreases and the image quality of the recorded image deteriorates. There are two disadvantages. This phenomenon is la>
Since it starts to occur in the region of 130 μm, preferably 1a ≦ 1
A value of 30 μm is desirable.

In the above description, the distances 1a and 1b will be examined. Looking at the uniformity of each droplet ejection amount among the factors for stabilizing the recording characteristics, the relationship between the distances 1a and 1b is 1a <
When it was lb, the ejection amount was stabilized. Therefore, in the embodiment of the present invention, 1a <1b, 90 μm ≦ 1a ≦ 130 μm
It was found that m, 1b ≦ 110 μm gave favorable results under all conditions for recording.

If the electrothermal transducers that are sequentially driven are not necessarily adjacent but are close to each other, the distance between the centers of the heat generating portions of the electrothermal transducers that are sequentially driven is particularly 100 μm or less, and more effectively 80 μm or less. If so, the effect according to the present invention sufficiently exists.

The present invention is more effective as the number of sets of liquid passages / electrothermal converters increases, and it has been found that a significant difference from the simultaneous drive method is found in 48 or more sets. Moreover, a particularly effective even when placed at high density discharge ports, heating area of the heating element from the stabilization of the discharge characteristics 4190Myuemu ² below, was also found to be 3390Myuemu ² or more are preferred conditions.

Here, an apparatus requiring an extremely long-term continuous drive was examined.

In an apparatus for performing recording having such characteristics, when lb has an extremely small value, meniscus vibration accompanying the return of the meniscus to the orifice portion after the ejection of the recording liquid droplets increases. In some cases, ink wetting at the orifice portion was observed after long-term recording. In this case, as a result, due to ink wetting, the rectilinear advance of the recording liquid drops, and the landing point accuracy on the recording medium is slightly lower than that of the present invention. It has been found that in the apparatus in such a case, it is preferable to set 1b ≧ 40 μm in order to further stabilize the image quality and the state of ejection of the recording liquid droplets. As the liquid path, the shape from the supply port to the heating element is preferably the same as lb ≦ 40 μm as shown in FIG.

On the other hand, a nozzle provided with a narrowed portion (hereinafter referred to as a fluid resistance element) for reducing the cross-sectional area of the ink flow path at the rear portion of the heater in the anti-discharge direction to prevent ink flow in the anti-discharge direction during foaming. In the case of the shape, the increase in the fluid impedance of the fluid resistance element makes it possible to guarantee the printing quality up to the lower 1b area as compared with the nozzle shape shown in FIG. Even in continuous recording, more preferable recording could be achieved if 1b ≧ 30 μm.

The driving pulse as the driving signal in this embodiment is described in US Pat. Nos. 4,463,359 and 4,345.
No. 262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, a combination of a plurality of recording heads as disclosed in the above-mentioned specification is used. Either a configuration that satisfies the length or a configuration as one integrally formed recording head may be used, but the present invention can more effectively exert the above-described effects.

In addition, the print head is exchangeable with a print head of the chip type, which is electrically connected to the main body of the apparatus and can supply ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge-type recording head provided in a fixed manner is used.

The present invention has an advantage that it is effective for color inks and can stabilize an image as a recording apparatus without being influenced by a recording head.

According to the present invention, the print data to the plurality of electrothermal transducers is divided and transferred to the print data of a plurality of bits, so that the electrothermal transducers adjacent to each other among the plurality of electrothermal transducers are transferred. This is particularly effective in an ink jet recording apparatus in which current is sequentially supplied at regular time intervals.

[0058]

According to the present invention, the printable recording frequency can be increased and the recording speed can be improved.
More industrial uses of the inkjet recording device can be enabled.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a correspondence relationship between a drive pulse time difference Td and a response frequency in relation to bubble formation.

FIG. 2 is an example showing drive timings (a) and (b) of the present invention.

FIG. 3 is a block diagram of an apparatus applied to the present invention.

FIG. 4 is a driving timing chart of each circuit used in FIG. 3;

FIG. 5 is a graph illustrating the effect of the liquid channel configuration itself applicable to the present invention.

FIGS. 6A and 6B are a partial explanatory view of a recording head divided drive according to another embodiment of the present invention and a configuration explanatory view of a liquid path communicating with a common liquid chamber C of the head; FIGS.

FIG. 7 is a diagram illustrating a specific supply timing of a drive signal different from FIG. 2;

FIG. 8 is a schematic view including a partial cross section of a recording head to which the present invention is applied.

[Explanation of symbols]

 11 Heating element Td pulse-pulse timing

Claims (5)

(57) [Claims] 1. A plurality of electrothermal transducers for discharging ink by generating thermal energy and generating bubbles in ink, and a pulse signal to be supplied to the electrothermal transducer is controlled based on print data and a control signal. A plurality of electrothermal transducers are divided into a plurality of groups using an ink jet recording head having a driving element, and the pulse signal is sequentially applied to each group of electrothermal transducers to discharge ink. In the ink jet recording method, between the time when the size of bubbles generated by applying a pulse signal to a certain group of electrothermal transducers becomes maximum and the time when the bubbles disappear, An ink jet recording method comprising: starting application of a pulse signal to a group of electrothermal transducers. 2. The method according to claim 1, wherein a period of time when 4 μs elapses from a point in time when the size of bubbles generated by applying a pulse signal to the certain group of electrothermal transducers reaches a maximum and a point in time when the bubbles disappear. 2. The ink jet recording method according to claim 1, wherein application of a pulse signal to a group of electrothermal transducers driven subsequently is started. 3. A plurality of electrothermal converters for discharging ink by generating thermal energy to generate bubbles in the ink, and a pulse signal applied to the electrothermal converter is controlled based on the recording data and the control signal. An ink jet recording head having a driving element, and transport means for transporting a recording material on which an image is formed by attaching ink ejected from the recording head to a recording position facing the recording head. An inkjet recording apparatus that divides the plurality of electrothermal transducers into a plurality of groups, and sequentially applies the pulse signal to each group of the electrothermal transducers to discharge ink, Between the time when the size of the bubble generated by applying a pulse signal to the body is maximized and the time when the bubble disappears, the pulse to the next group of electrothermal transducers to be driven next An ink jet recording apparatus characterized by comprising a control means for starting the application of No.. 4. The method according to claim 1, wherein the control unit determines a time when 4 μs elapses from a time when a size of a bubble generated by applying a pulse signal to the certain group of electrothermal transducers becomes maximum, and a time when the bubble disappears. 4. The ink jet recording apparatus according to claim 3, wherein the means for starting application of a pulse signal to a group of electrothermal transducers that is driven subsequently during the period. 5. The ink jet recording head has a discharge port for discharging ink, and a flow path communicating with the discharge port and a supply port for receiving the supply of the ink, in which the electrothermal transducer is arranged. And the distance la of the flow path between the discharge port and the electrothermal transducer is 90 μm ≦ la ≦ 130 μm
In a distance lb of the flow passage lb ≦ 110 [mu] m between the anti-discharge direction end portion and the supply port of the electrothermal transducer, la <l
4. The ink jet recording apparatus according to claim 3, wherein the relationship b is satisfied.