JPH03227637A - Liquid jet recording head and ink jet recorder using the head - Google Patents

Abstract

PURPOSE:To eliminate the influence of variation in ink pressure and thereby obtain a high-quality image using a compact device by sequentially performing drive control of a plurality of drive circuits performing selective conduction of a plurality of electrothermal conversion elements based on a driving order setting data. CONSTITUTION:A strobe terminal is provided for each drive IC 5 consisting of a 64-bit shift register 4, a 64-bit latch circuit 3, an AND circuit 2 and a transistor for thermal element drive. The thermal element 1 is driven in the divided drive mode through the drive transistor corresponding to only an AND circuit 2 to which a strobe signal entered from a drive sequential order control circuit 6 and an output from the 64-bit latch circuit 3 corresponding to each thermal element 1 are connected. The control circuit 6 interprets in which drive sequential order the thermal elements should be driven based on m-bit pattern data to be entered in drive sequential order setting data input terminals Do to Dm. Thus density irregularities can be eliminated without structural complication.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a liquid ejection recording head for ejecting recording droplets to perform recording on a recording medium, and an inkjet recording apparatus using the head. .

[Prior Art] A liquid jet recording method (inkjet recording method) is a recording method in which droplets of recording liquid are formed by various methods, and the droplets are attached to a recording material such as paper to perform recording. .

Among recording devices that apply this type of recording method, a type of liquid that uses heat as energy to form ejected droplets is a device that has a structure suitable for creating high-density multi-orifice droplet ejection holes in the print head. One example is a recording device.

Liquid ejection recording devices that use heat as energy for ejecting droplets usually heat the recording liquid to cause a change that causes a rapid increase in volume, and eject it from an orifice in the nozzle to increase the volume of the recording liquid. The recording head includes a plurality of droplet forming means for forming droplets and a plurality of electrothermal energy conversion elements that can generate heat and heat the recording liquid by applying an electric signal.

A conventional liquid ejecting recording head (shown in FIG. 5) has such an electrothermal energy conversion element (hereinafter referred to as a heating element), and in particular, a plurality of heating elements corresponding to the recording width of one line are arranged. The liquid jet recording head has
A method is used in which the head is divided into several blocks and a group of heating elements corresponding to each block is driven. For example, a circuit block diagram as shown in FIG. 5 provides drive timing as shown in FIG. 6. In FIG. 5, 1 is a heating element, 2 and 21 are AND gates, 22 is a flip-flop, 3 is a latch, and 4 is a shift register, and the shift register 4 operates based on the clock Sclk and outputs data (SI). Latch 3 receives the latch signal (LA
T) Upon input, the data from the shift register 4 is latched, and the flip-flop 22 takes in the divided drive signal transfer clock Eclk and the divided drive signal El. Also, the AND gate 21 is connected to each block (components 3 and 4 are each 1
A signal BEI that controls the energization time for each unit is input to one input terminal.

Then, the AND gate 2 receives data at one input terminal and an STB signal corresponding to the BEI of each block at the other input terminal, and thus each heating element 1 is driven.

In this way, a group of heating elements corresponding to one drive IC is defined as one block, and is sequentially driven. This block drive method has been used conventionally because the power consumption for driving the liquid jet recording head is significantly reduced compared to a method that does not perform block drive.

[Problem to be solved by the invention]

However, in this type of device, the recording liquid (hereinafter referred to as ink) is foamed by energizing a heating element, and the ink is ejected directly from the nozzle of the liquid jet recording head using the resulting pressure to perform recording, so the ink is always stable. In order to maintain the printer in a state where it can be ejected, special considerations not seen in other types of recording devices are required.

In other words, when the heating element is energized to eject foam, the ink in adjacent nozzles may vibrate due to the influence of the pressure, and if adjacent nozzles are driven continuously, the pressure fluctuations As a result, ejection becomes unstable, the amount of ejected liquid changes, and density unevenness may occur in recording.

Fluctuations in the amount of ejected liquid due to fluctuations in ink pressure become more pronounced as the number of simultaneously driven bits increases and the distance from the ejection nozzle becomes shorter, and is also greatly affected by the shape of the common liquid chamber that communicates with each nozzle. Ru.

To do this, it is necessary to make the ink chamber wider so that changes in ink pressure do not affect other nozzles, and to adjust the driving time of adjacent heating elements at intervals, and to reduce the size of the head. and become an obstacle to high-speed recording.

In order to solve this problem, it may be possible to drive all nozzles at the same time, but since the current flowing through the heating element per nozzle is as large as several tens of milliamps, the current that flows during driving becomes large, making the power supply smaller.

This is not suitable for downsizing the head, and a method of time-division driving of multiple nozzles as one block is generally used.

The present invention has focused on such problems, and aims to provide a liquid ejection recording head that is small and has high recording quality, and an inkjet recording apparatus using the head, which eliminates the influence of ink pressure fluctuations on recording. .

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a recording head for ejecting recording droplets to perform recording on a recording medium, which includes a plurality of electrothermal transducers and a plurality of electrothermal transducers. The present invention is characterized by comprising a plurality of drive circuits for selectively energizing electrothermal conversion elements, and a control means for driving and controlling the plurality of drive circuits in an order based on drive order setting data.

[For production]

According to the present invention, by connecting a strobe terminal provided for each drive IC to a drive order control circuit mounted on the print head, a drive order pattern is arbitrarily selected so as to bring the print head into a stable ejection state, and an adjacent The blocks are designed to be energized at a timing such that the influence of ink pressure caused by ejection is sufficiently eliminated.

〔Example〕

FIG. 1 shows a liquid jet recording head to which the present invention can be applied, and particularly shows a so-called full-line type head in which discharge ports are aligned over a range corresponding to the entire width of a recording medium.

Here, 14 is a heating element that constitutes an electrothermal transducer that generates heat in response to electricity, causes foaming in the ink, and ejects ink droplets by the growth and contraction of the bubbles. ll through the same manufacturing process as semiconductors. 12A is a liquid path forming member for forming a discharge port 12 and a liquid path 13 communicating therewith in correspondence with the heating element 14, and 16 is a top plate. Also 15
is a liquid chamber common to each liquid path 13, and stores ink supplied from an ink supply source (not shown).

FIG. 2 shows an example of the electrical configuration of a liquid jet recording head having the mechanical configuration shown in FIG. It is a block diagram.

In FIG. 2, SI is a recording data input terminal, 5cl
k is a transfer lock input terminal for transferring recording data input to SI. 4 is a 64-bit shift register, and each output corresponds to the heating element 1 individually. One line of recording data is transferred to the shift register 4 by Sr, 5clk, and then loaded into the latch circuit 3 by the latch input input to the LAT input terminal connected to the 64-bit latch circuit 3. The drive order control circuit 6 is for selecting the heating elements 1 according to recording data, as will be described later.

That is, in FIG. 2, each driving IC is composed of a 64-bit shift register 4, a 64-bit latch circuit 3, an AND circuit 2, and a heating element driving transistor.
A strobe terminal is provided every 5, and only the AND circuit 2 in which the strobe signal input from the circuit 6 and the output of the 64-bit latch circuit 3 corresponding to each heating element 1 are input to the strobe terminal is compatible. The heating element is driven through the driving transistor. This allows the heating element 1 to be driven in segments.

Regarding this divided drive, the drive order control circuit 6 controls D0
The drive order to be used is determined based on the m-bit pattern data input to the drive order setting data input terminals of ~D, and the strobe terminal provided for each sequential drive IC is activated. FIG. 3 shows an example of a drive order pattern based on signals output to the strobe terminal (the numbers indicate the order in which the drive ICs are mounted).

Pattern O and pattern 1 indicate normal divided drive timing, each having 64 bits.

It simultaneously drives 128-bit heating elements. Patterns 2 and 3 are examples of drive order timings prepared in the present invention to improve recording quality. In particular, since pattern 3 does not drive adjacent drive ICs continuously, it is possible to improve recording quality such as density unevenness.

In this pattern, every other drive IC is driven, but it goes without saying that every few drive ICs can be driven. If the level of density unevenness slightly differs depending on the liquid jet recording head, a pattern can be selected depending on the print quality.

By providing a drive order control circuit that prepares a plurality of patterns in this manner, it is possible to arbitrarily set an optimal pattern according to printing quality.

[Other Examples]

Next, a second embodiment of the present invention is shown in FIG.

The second embodiment shown in FIG. 4 is different from the embodiment shown in FIG. By adding a drive order setting circuit 7 for supplying control data to the drive order setting circuit 7, it is possible to search recording data line by line and determine the optimum drive order for recording.

Recorded data input terminal SI and data transfer lock 5c
lk is supplied to a 64-bit shift register 4, and also supplied to a line buffer 9 and a counter 8 that counts the position of record information in one line of record data. Recorded information search unit 1O, which includes line buffer 9 and counter 8, searches for recorded information based on these inputs. The output of the record information search unit 10 is supplied to a drive order setting circuit 7, where drive order pattern data optimal for the record information is obtained. This is input to the drive order control circuit 6. When driving for one line is determined in this way, recording is started by inputting to the LAT terminal (the operation is the same as in Fig. 2), and at the same time the line buffer 9
Then, the counter 8 is cleared, and recording data for the next line is input.

With the above control, for example, if the recorded data is likely to cause density unevenness, a driving order pattern is selected according to the data.
In cases where there is almost no recorded information, it becomes possible to change the driving method for each line, such as selecting a simultaneous driving pattern such as pattern 4 in FIG. Therefore, not only the recording quality is improved, but also the recording speed can be reduced for lines with less recording information.

By using the liquid jet recording head and its control system as described above, a line printer capable of full-color recording as shown in FIG. 7 can be constructed.

In FIG. 7, 201A and 201B are recording media R
This is a pair of rollers provided for holding and conveying the image in the sub-scanning direction V. In 2028, 202Y, 202M and 2
02C is a full-line liquid ejecting recording head to which the above-described embodiment is applied, in which nozzles are arranged over the entire width of the recording medium R and perform recording in black, yellow, magenta, and cyan, and the recording medium is conveyed in that order. It is placed from the upstream side. 200 is recovery type,
During the ejection recovery process, instead of the recording medium R, the liquid ejecting recording head 2028 faces ~202C.

It should be noted that each of the embodiments described above brings about excellent effects in a bubble jet recording head and recording apparatus among ink jet recording methods. This is because such a system can achieve higher recording density and higher definition.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. The electrothermal converter that is
Generating thermal energy in the electrothermal transducer and producing film boiling on the thermally active surface of the recording head by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise above nucleate boiling. This is effective because, as a result, bubbles in the liquid (ink) can be formed in pairs corresponding to the drive signals. The growth and contraction of this bubble causes the liquid (ink) to be ejected through the ejection opening to form a small droplet (at least one droplet).If this drive signal is in the form of a pulse, the growth and contraction of the bubble will occur immediately and appropriately. Because you will be exposed to
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the wafer is placed in a bending region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration in which a discharge portion is made to correspond to an opening that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. In other words, regardless of the form of the recording head, recording can be performed reliably and efficiently.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus, to the present invention, because the effects of the present invention can be further stabilized. Specifically, these include capping means for the recording head, cleaning means, pressure or suction means, preheating means using an electrothermal transducer or another heating element, or a combination thereof; It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

In addition, in addition to being used as an image output terminal for information processing equipment such as a computer, the inkjet recording apparatus of the present invention may also take the form of a copying machine combined with a league, etc., or a facsimile machine having a transmission/reception function. It may be something.

〔Effect of the invention〕

As described above, according to the present invention, since a drive order pattern can be arbitrarily selected, density unevenness can be eliminated and recording quality can be improved without complicating the interior of the drive IC.

Further, as in the second embodiment, it is also possible to perform high-speed recording by changing the drive pattern by searching recording information line by line.

As long as the present invention provides the above-mentioned effects, it goes without saying that the same effects can be obtained even if the present invention is a serial printer head that includes several drive ICs mounted on the liquid ejection recording head. Even if the drive IC has a complex drive circuit that can control the pulse width for each heat generating element, it will show the same effect, and it will be limited to the application of the liquid ejection recording head and the resolution. It's not something that can be done.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a configuration example of a liquid jet recording head to which the present invention can be applied; FIG. 2 is a block diagram showing a drive control system of a liquid jet recording head according to an embodiment of the present invention; FIG. 4 is a block diagram showing a drive control system for a liquid jet recording head according to another embodiment. FIG. 5 is a conventional drive control system for a liquid jet recording head. FIG. 6 is a timing chart showing a conventional drive system, and FIG. 7 is a perspective view showing the configuration of a full-color printer to which the liquid jet recording head of the present invention is applied. DESCRIPTION OF SYMBOLS 1...Heating element, 2...AND circuit, 3...Latch circuit, 4...Shift register, 5...Drive IC1 6...Drive order control circuit, 7...Drive order Setting circuit, 8...Counter, 9...Line buffer, lO...Print information search section. Figure 1 Figure 7!

Claims (1)

[Scope of Claims] 1) In a liquid ejection recording head for ejecting recording droplets to perform recording on a recording medium, a plurality of electrothermal transducer elements and selectively energizing the plurality of electrothermal transducer elements are provided. 1. A liquid ejection recording head comprising: a plurality of drive circuits for controlling the drive circuit; and a control means for driving and controlling the plurality of drive circuits in an order based on drive order setting data. 2) In an inkjet recording apparatus that performs recording by discharging liquid onto a recording medium, a plurality of electrothermal transducers, a plurality of drive circuits for selectively energizing the plurality of electrothermal transducers, and drive order setting. An inkjet recording apparatus comprising: a control means for driving and controlling the plurality of drive circuits in an order based on data; a liquid ejection recording head comprising: a conveying means for conveying a recording medium. 3) The liquid ejection recording head according to claim 1, wherein the drive order setting data in the control means is variable for each head depending on the recording characteristics of the head. 4) The control means has a line buffer for storing one line of recording data and a counter for counting recording information, and makes drive order setting data variable based on the line buffer and counter. The liquid ejection recording head according to claim 1, characterized in that: 5) The liquid discharge recording head and recording apparatus according to each of the preceding claims, wherein the recording head is a bubble jet recording head that discharges ink droplets by the growth and contraction of air bubbles.