JPH03227632A - Driving method of ink jet recording head and recorder - Google Patents

Abstract

PURPOSE:To make possible the high-speed recording of data in a high quality state using a compact ink jet printer by providing drive elements performing conduction control of electrothermal conversion elements sequentially in units of block, and sequentially driving every several blocks. CONSTITUTION:Recorded data S1 consisting of the same number of bits as the number of electrothermal conversion elements is input synchronously to a clock signal CLK for recorded data transmission, then this recorded data is read into a latch circuit 5 in a drive IC 3 by a latch signal LAT. After that, the block of the electrothermal conversion elements which can be energized is shifted upon input of a signal EI for divided drive and a clock ECK for transferring a divided drive signal, and each block begins to be energized by the input of a signal ENB. The signal EI and the clock ECk are input at such a timing that every other group of the blocks is energized, that is, a power is turned ON to every other group of two blocks. Subsequently, the adjacent blocks are no longer driven continuously, so that a pressure variation is propagated to an adjoining ink path when the ink is discharged. Thus the irregularities in density nuance of a recorded image can be eliminated using a simple device.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for driving an inkjet recording head and a recording apparatus using the driving method, and particularly to a method for driving a full multi-type recording head and a recording apparatus using the driving method. This relates to recording devices that were previously used.

[Prior Art] An inkjet recording apparatus is a recording apparatus that performs recording by forming ejected droplets of ink using various methods and attaching the droplets to a recording material such as recording paper. Among these, inkjet recording devices that use heat as energy to form ejected droplets have the advantage of being able to easily realize high-density multi-nozzle configurations, allowing high-resolution, high-quality images to be obtained at high speed. It has characteristics.

This type of inkjet recording device has a plurality of droplet forming means for ejecting ink ti and droplets from an ejection port by applying thermal energy to the ink, that is, a current pulse is supplied to generate heat and heat the ink. A droplet forming means having an electrothermal transducer capable of
A plurality of recording heads are arranged on the same substrate to constitute a recording head for a line printer, that is, a so-called full multi-type recording head in which ejection ports are aligned over the entire width of the recording material.

FIG. 7 shows an example of the configuration of a driving device for an inkjet recording head of this type, and FIGS. 8 and 9 show the driving timing thereof. In FIG. 7, 2 is an electrothermal converter provided corresponding to a plurality of ink ejection ports (not shown), and print data (SI; 13-b) having the same number of bits as the electrothermal converter 2 is As shown in FIG. 8, data is sequentially transferred to the shift register 4 in the driving ICa in synchronization with the data transfer clock (CLK).
The transferred recording data SI is read into the latch circuit 5 by inputting a latch signal (LAT) after all data has been input.

After that, the flip-flop (
The driving ICs 3 are sequentially activated by the F/Fl 6, and the electrothermal transducer 2 whose recording data signal of the driving ICE is ON is activated only while the pulse width setting signal (ENB) is ON. Ink is ejected from the ejection ports 13 by selectively energizing them in the order shown in the figure.

[Problem to be solved by the invention J] By the way, in this type of device, the electrothermal converter 2 is contained in the ink.
Since air bubbles are generated by energization and the pressure of the bubbles causes ink to be ejected directly from the ink ejection openings of the print head to perform printing, it is desirable to keep the ink in a stable state at all times so that it can be ejected.

That is, when ink is ejected by energization of the electrothermal transducer 2, the pressure fluctuations generated at that time may vibrate the ink in the adjacent liquid path via the common liquid chamber. Therefore, if electrothermal transducers placed in adjacent wave paths are continuously driven, the pressure fluctuations will cause the ejection to become unstable, and the amount of ejected liquid will change, causing unevenness in recorded images. becomes. Note that fluctuations in the amount of ejected liquid due to such fluctuations in ink pressure become more subtle as the number of bits that are continuously driven at the same time is larger, and the distance from the ejection ports is shorter. It is also greatly influenced by the shape of the liquid chamber.

Therefore, it is necessary to make the common liquid chamber wider or to lengthen the driving interval for adjacent electrothermal transducers so that changes in ink pressure do not affect ink ejection operations from other ejection ports. These problems have been an obstacle to miniaturization of the recording head and high-speed recording.

In order to solve this problem, it may be possible to drive all the electrothermal converters simultaneously, but the current flowing through one electrothermal converter is as large as several tens of mA to several hundred mA.

For this reason, the amount of current required during driving increases, making it unsuitable for downsizing the drive power source and recording head.Therefore, a method of configuring multiple electrothermal transducers into one block and driving them in a time-division manner is not suitable. has been used.

The purpose of the present invention is to focus on such problems, and to solve the problems, it is an inkjet recording head that eliminates the influence of ink pressure fluctuations on recorded images by relatively simple means, and is capable of compact, high-quality, and high-speed recording. An object of the present invention is to provide a driving method and a recording apparatus using the driving method.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a plurality of electrothermal transducers that generate thermal energy for forming recording droplets, and a plurality of electrothermal transducers that are divided into a plurality of blocks. An inkjet recording head comprising a drive element that sequentially controls energization of the converter in block units, and sequentially drives every plurality of blocks so that adjacent blocks of the electrothermal converter are not driven consecutively. The present invention relates to a driving method and a recording apparatus.

[Function] According to the present invention, since the drive order is assembled by the means for generating the drive signal feeding order so that adjacent drive blocks are not driven consecutively, the ink ejecting operation is performed for each block. Fluctuations in ink pressure due to this do not affect the flow path of the next block to be ejected, making it possible to prevent uneven density from occurring, and also to realize miniaturization and high-speed recording of the apparatus.

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

FIG. 1 shows an inkjet recording head to which the present invention can be applied, and particularly shows a so-called full multi-type inkjet recording head in which ejection ports are aligned over a range corresponding to the entire width of a recording material.

Here, reference numeral 11 denotes a heat generating resistor that constitutes the electrothermal conversion element 2 that generates heat in response to energization, generates bubbles in the ink, and causes ink to be ejected.
It is formed on the top through the same manufacturing process as semiconductors. 1
3A is a liquid path forming member 1 for forming a discharge port 13 corresponding to the heating resistor 11 and a flow path 14 communicating therewith;
5 is a top plate. Further, 16 is a common liquid chamber commonly communicating with each flow path 14, and stores ink supplied from an ink supply source (not shown).

FIG. 2 shows an example of a drive control system for an inkjet recording head l having a mechanical configuration as shown in FIG. 1 and an electrical configuration capable of driving a plurality of electrothermal conversion elements 2 for each block as shown in FIG. show.

Reference numeral 20 denotes a head drive circuit according to the present embodiment, which includes a gate circuit (not shown), a head drive power supply 21, a timing generation circuit 22, and a recording data/drive timing generation circuit 23.
have.

Therefore, in the head drive circuit 20 configured as described above, the timing generation circuit 22 generates the pulse width setting signal ENB and the divided drive signal EI in response to the control signals C1 and C2 from the recording data/drive timing generation circuit 23.
, divided drive signal transfer lock ECK and latch signal L
AT is generated and supplied to each driving IC 3 of the recording head l.

FIG. 3 shows the drive timing of this embodiment. After recording data Sl, which is composed of the same number of bits as the electrothermal transducer 2, is input in synchronization with the recording data transfer clock CLK, the latch signal LAT After being read into the latch circuit 5 in the drive IC 3, the blocks that can be energized are shifted by inputting the divided drive signal EI and the divided drive signal transfer lock ECK, and the energization of each block is started by inputting the signal ENB. Begins. In this case, the divided drive signal EI and the divided drive signal transfer lock ECK are inputted at a timing such that energization is performed every other block as described later, and the fourth block is inputted according to the timing shown in FIG. As shown in the figure, electricity is supplied to every two blocks.

FIG. 4 shows an example of the energization and ejection order performed for each block consisting of 1 to 3n in this embodiment. In the case of a head, if there are 64 electrothermal transducers 2 connected to one drive IC 3 and 128 electrothermal transducers driven simultaneously, 37 blocks are sequentially ejected every two blocks. Then, the recording will be made.

FIGS. 5 and 6 show timing, energization of each block, and ejection order according to another embodiment. In this example, the number of bits in one block is reduced, and blocks n blocks apart are simultaneously driven to reduce the influence of the pressure of ejected ink. In this embodiment, the interval between sequentially energized blocks is every 1 or 2 blocks, but the minimum interval between sequentially energized blocks depends on the shape and dimensions of the liquid chamber, the number of simultaneously driven bits, etc. The interval should be set appropriately according to the requirements, and the interval is not limited to a specific one.

By using the recording head driving method as described above, it is possible to construct a line printer capable of full-color recording as shown in FIG. 10, for example. Next, its configuration will be explained.

In FIG. 10, 201A and 201B are a pair of rollers provided to nip and convey the recording medium R in the sub-scanning direction V. 2028K, 202Y, 202M, and 202C are full multi-type recording heads that perform black, yellow, magenta, and cyan recording in which nozzles are arranged over the entire width of the recording medium R, in that order from the upstream side in the recording medium conveyance direction. It is arranged.

A recovery system 200 faces the recording head 2028 to 202C instead of the recording medium R during ejection recovery processing. In this line printer, using the head driving method described above, the head 2028 has two
Performs drive control of 02Y, 202M, and 202C.

It should be noted that the present invention provides excellent effects particularly in bubble jet recording heads and recording apparatuses among ink jet recording systems.

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. In particular, in the case of the on-demand type, the electrothermal transducer placed corresponding to the sheet holding the liquid (ink) or the liquid path is required to respond to the recorded information and rapidly exceed nucleate boiling. By applying at least one drive signal that causes a temperature increase, the electrothermal transducer generates thermal energy and causes film boiling on the thermally active surface of the recording head, resulting in a one-to-one response to this drive signal. This is effective because it can correspondingly form bubbles within the liquid (ink). 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. This makes it possible to eject liquid (ink) with particularly excellent responsiveness, which is more preferable.This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262. Further, 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 is a combination configuration of an ejection port, a liquid path, and an electrothermal converter as disclosed in the above-mentioned specification (
U.S. Pat. No. 4 discloses a structure in which a heat acting part is arranged in a bending region in addition to a straight liquid flow path or a right-angled liquid flow path.
558333 and US Pat. No. 4,459,600 are also included in the present invention. In addition, Japanese Patent Application Laid-Open No. 59/1989 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
-123670 and Japanese Patent Laid-Open No. 59/1989 disclosing a configuration in which an opening for absorbing pressure waves of thermal energy corresponds to a discharge part.
The effects of the present invention are also effective even with a configuration based on the publication of No. 138461. In other words, regardless of the form of the printhead, printing can be performed reliably and efficiently.

Further, the present invention can be particularly effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus. Such a recording head may have either a configuration in which the length is satisfied by a combination of a plurality of recording heads, or a configuration as a single recording head formed integrally. In addition, even the serial type shown above can be installed on the main body of the device, allowing for electrical connection to the main body of the device and supply of ink from the main body of the device.Replaceable chip type recording heads. Alternatively, the present invention is also effective when using a cartridge type recording head that is integrally provided with the recording head itself.

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, regarding the type and number of recording heads installed, for example, in addition to one type that corresponds to single-color ink, there is also a plurality of recording heads that correspond to multiple inks with different recording colors and densities. It may be something that can be done.

In addition, the inkjet recording apparatus of the present invention may take the form of an image output terminal for information processing equipment such as a computer, a copying apparatus combined with a reader, etc., or a facsimile apparatus having a transmitting/receiving function. It may be something.

[Effects of the Invention] As explained above, according to the present invention, since adjacent blocks are not driven continuously, pressure fluctuations that occur during ink ejection are propagated to adjacent liquid paths and It is possible to eliminate unevenness in recorded images due to fluctuations in ink pressure with a relatively simple means, and it has become possible to provide an inkjet recording device that is small and capable of high-speed, high-quality recording. Ta.

[Brief explanation of drawings]

FIG. 1 is a partially exploded perspective view showing the configuration of an inkjet recording head to which the present invention is applied, FIG. 2 is a block diagram showing the circuit configuration of the recording head drive system according to the present invention, and FIG. 3 is a block diagram showing the circuit configuration of the recording head drive system according to the present invention. FIG. 4 is an explanatory diagram showing the driving order of the drive blocks according to the timing shown in FIG. 3. FIG. 5 is a diagram showing the timing of various signal generation by the drive system circuit of the present invention. Figure 6 is an explanatory diagram showing the driving order of the drive blocks according to the timing shown in Figure 5. Figure 7 is a block diagram showing the circuit configuration of a conventional inkjet recording head. Figure 8 is a diagram showing other timing examples. FIG. 9 is an explanatory diagram showing the driving order of drive blocks according to the timing shown in FIG. 8. FIG. 10 is a line printer using the head driving method of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Recording head, 2... Electrothermal transducer (electrothermal transducer), 3... Drive IC1 4... Shift register, 5... Latch circuit, 13... Ejection port, 14... Liquid path, 20... Head drive circuit, 22... Timing generation circuit, 23... Record data drive timing generation circuit, Sl.
...Recording data, ENB...Pulse width setting signal, 202Y, 202M, 202G, 2028K...
・Recording head, EI...Segment drive signal. 1st factor 1 13-b 3-b Figure 8

Claims (1)

[Claims] 1) A plurality of electrothermal converters that generate thermal energy for forming recording droplets, and a drive that sequentially controls energization of the electrothermal converters divided into a plurality of blocks in units of blocks. A method for driving an inkjet recording head, comprising: driving every plurality of blocks sequentially so that adjacent blocks of the electrothermal transducer are not driven consecutively. 2) The method for driving an inkjet recording head according to claim 1, wherein the blocks of electrothermal transducers to be driven simultaneously are divided into a plurality of blocks so as not to be adjacent to each other, and the blocks are sequentially driven. 3) The method of driving an inkjet recording head according to claim 1, wherein the block includes a plurality of connected bits. 4) A plurality of electrothermal transducers disposed corresponding to each of the arrayed ejection ports and generating thermal energy used for ejecting ink in accordance with a drive signal, and the plurality of electrothermal converters. a drive control element that is provided in each of a plurality of drive blocks consisting of the same number of electrothermal transducers arranged in the order of arrangement from the body, and that controls the electrothermal transducers in the drive block so that they can be driven simultaneously; and at least an adjacent drive block. The recording medium is characterized by comprising: means for generating a feeding order of the drive signals supplied via the drive control element so that the blocks are not driven continuously; and a conveyance means for conveying the recording medium. Inkjet recording device. 5) The inkjet recording apparatus according to claim 4, wherein the drive blocks that are not adjacent to each other are driven at the same time. 6) In the inkjet recording, a rapid temperature rise that exceeds nucleate boiling causes film boiling on the heat-active surface of the recording head, forming bubbles in the ink, and the growth and contraction of these bubbles causes the ink liquid to flow out from the ejection port. The driving method and recording apparatus for an inkjet recording head according to each of the preceding claims, which is a bubble jet recording method in which droplets are ejected.