JPH03213356A - Ink jet recording device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inkjet recording device, and in detail,
The present invention relates to an inkjet recording device that is capable of empty ink discharge from the ink discharge ports of a recording head in order to prevent clogging of the ink discharge ports.

[Prior Art] An inkjet recording device is known as a device that performs recording by ejecting ink toward a recording material, causing the ink droplets to land and settle, and because it is a non-impact type, it produces less noise (, Further, it has the characteristic that it is easy to record a color image by using multicolor ink, and has become particularly popular in recent years.

By the way, inkjet recording devices perform recording by directly ejecting ink onto the recording material from fine ink ejection ports, and in order to always obtain stable recorded images, other types of recording devices are used. Special consideration is required that cannot be seen in other countries. For example, if you have a multi-nozzle type print head in which many ink ejection ports are arranged or a print head unit consisting of a plurality of print heads, the ink ejection ports that are rarely involved in printing during printing operation, In the print head, moisture in the ink evaporates from around the ink ejection ports, causing ejection failure due to increased ink viscosity and dust sticking. Therefore, guide the print head out of the print area and eject ink all at once from the ink ejection ports. A series of recovery operations such as dry ejection have been performed.

[Problems to be Solved by the Invention] However, in conventional inkjet recording devices in which idle ejection is performed as described above, in a multi-nozzle type recording head or a recording head unit consisting of a plurality of recording heads, the above-mentioned Regardless of the degree of involvement in recording during the recording operation or the difference in ink dye, -
Dry ejection has been performed with the same number of pulses as the rate. This method is not efficient because the length of time that can be left without worrying about dry ejection differs depending on the ink dye, and whether or not dry ejection is necessary changes depending on the degree of involvement in recording. .

An object of the present invention is to provide an inkjet recording apparatus that can perform effective idle ejection by changing the number of idle ejection pulses supplied to each nozzle or recording head depending on the degree of involvement in recording and the type of ink. It's about doing.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an ink ejection port provided in each of a plurality of recording heads and a liquid path communicating with the ink ejection port, and ink is provided in the ink ejection port. and an ejection energy generating means for ejecting the ink from the ejection port, and performs recording by ejecting ink with different characteristics from each of the recording heads, and also drives the ejection energy generating means to eject the ink during a recovery operation. In the inkjet recording device capable of dry ejection, the inkjet recording apparatus includes means for setting the dry ejection according to the characteristics of the ink. drive that thing.

[Function] Generally, the ejected ink of a plurality of recording heads has different characteristics such as color and density, and therefore, the length of time that the ink can be left without being ejected differs depending on the ink, but according to the present invention Since the driving conditions for the ejection energy generating means that are driven for dry ejection are set differently depending on the characteristics of the ink, the dry ejection can be performed rationally and effectively, and the recovery operation to prevent clogging can be performed. can contribute to

[Example] The present invention will be described in detail below based on the drawings.

FIG. 1 shows an example of a bubble jet type inkjet recording apparatus to which the present invention is applied. This example is for a multi-color recording device, where 1 is shown in FIG. 1m 71n sold) ^6-s tongue =
A recording head unit, in which individual recording heads IA to I
D has an array of a plurality of ink ejection ports 100, and printing liquids of different colors are ejected from the respective print heads IA to ID. Further, an electrothermal transducer 200 as an ejection energy generating means to which an applied voltage is supplied to generate thermal energy for ejecting the recording liquid is arranged along the liquid path 300 of each recording head IA-ID. has been done.

2 is a carriage on which the recording head unit 1 is mounted and moves along a guide rail 3; 4 is a timing belt for moving the carriage 2; and 5 is a carriage drive motor. Further, the recording sheet 6 is moved by a sheet feed roller 8 driven by a sheet feed motor 7. The sheet is held at the recording position by a holding roller pair 9 that cooperates with the sheet feeding roller 8, and the sheet is fed in the direction of the arrow every time recording of the -share is completed. 11 is a supply pipe that supplies ink to each of the recording heads IA to ID, 12 is a return pipe that returns ink from the recording heads IA to ID to the tank 13, and 14 is a supply pipe that supplies ink to the recording heads IA to ID, respectively. This is a recovery device for multiple recording heads that faces the head unit 1 and discharges ink through idle ejection to prevent ejection failure.

FIG. 3 shows an example of the configuration of a control system for controlling the inkjet recording apparatus of the present invention. Here, 20 is a control unit, which includes a CPU 21 that executes a recording operation and a blank ejection operation according to the procedure described later, a ROM 22 that stores programs and fixed data corresponding to the procedure, and a host device 30.
It has a RAM 23, etc., which temporarily holds print data etc. sent from the print head 1A to ID, and stores the ink ejection diameter from each ejection port 100. Further, 24 is a driver that drives the plurality of recording heads LA-10 individually and supplies pulses for idle ejection as will be described later during recovery. 25 is a driver for the carriage motor 5; 26
is a driver for the sheet feed motor 7.

Next, a description will be given of the idle ejection operation during printing by the control unit 20 in the inkjet printing apparatus configured as described above. In this example, the printing heads IA, IB, IC, and l
In D, recording is performed by ejecting cyan, magenta, yellow, and black inks, respectively. Furthermore, the recording heads LA, IB, IC, and ID used in this example each have a resolution of 400 dpi and 128 ink ejection ports, and the dye concentrations (wt, %) of the four color inks mentioned above are shown in Figure 4. As shown in the table below, when printing is performed by ejecting these four colors of ink using the print head of this example, the allowable time (minutes) for achieving a stable ejection condition is as shown in the figure. It differs depending on the color.

Therefore, for example, in the case of black ink, the stable ejection time is extremely short at 5 minutes, so if the four colors are to be idle ejected at the same time interval, the pulse for black ink for the idle ejection is It is more effective to increase the number of pulses compared to other colors; conversely, for cyan and yellow, the number of idle ejection pulses may be small. Therefore,
In this embodiment, dry ejection is carried out for each color recording head every 4 minutes of the recording time, and at the same time, a dry ejection is performed for the dry ejection at that time. ! SE8-Douwagiwa 1 sun pulse for S Noan, 80 pulses for magenta, 50 pulses for yellow, and 100 pulses for black, and a good clogging prevention effect due to dry ejection was confirmed for all recording heads. did it.

FIG. 5 shows the procedure of the idle ejection operation according to the present invention. The power is turned on, a series of initial processing is performed, and step Sl
When printing is started, scanning for printing is performed in step S2. Then, in step S3, it is determined whether or not a predetermined recording time has elapsed, scanning for recording is continued until the predetermined time has elapsed, and when the predetermined time is reached, the recording head is returned to the home position in step S4. Then, in step S5, as described above, for each print head IA to ID, idle ejection is performed for the number of pulses corresponding to the color of ink ejected by that print head, and the process returns to step S2 to perform printing. Although not shown in this flow, when recording ends, various operations are performed according to the recording end processing routine.

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! 7, the number of pulses during idle ejection was varied according to the number of pulses during idle ejection, but instead, the head drive voltage or pulse width during idle ejection was changed based on the stable ejection time, which is related to the dye concentration and characteristics of the ink. You can. Furthermore,
A special timer may be provided to maintain appropriate time intervals according to the usage of each ink.

In addition, as another example, when ink of the same color but with different shading is used for each recording head, or even in the case of full color, the number of pulses of blank ejection may be changed depending on the color of the ink used. Or, regardless of the color of the ink (for each nozzle unit that ejects ink even in one recording head, refer to its ejection history, and increase the number of empty ejection pulses for nozzles that eject less number of times. It is also possible to construct a structure in which idle ejection is performed at predetermined time intervals in this manner.

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. 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. 9-123670, which discloses a configuration in which an opening for absorbing pressure waves of thermal energy corresponds to a discharge part.
'l I+l1ljha 10 eight illusions 1 groaning - origination + b1 e enemy four small effects are effective. In other words, regardless of the form of the recording head, recording can be performed reliably and efficiently.

Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording material 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 in which a single recording head is formed in one direction. 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.

[Effects of the Invention] As explained above, according to the present invention, the air condition is set for each recording head according to the characteristics of the ink used, so that the individual It is possible to perform idle ejection to the print head, and ink is not wasted, and stable printing is guaranteed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of an inkjet recording device to which the present invention is applied, FIG. 2 is a perspective view of a recording head unit installed in the recording device of FIG. 1, and FIG. 3 is a control according to the present invention. A block diagram showing the configuration of the system circuit, FIG. 4 is a table showing an example of the setting of the ejection energy generating means driving conditions during dummy ejection according to the present invention, and FIG. 5 shows the recording and dummy ejection operation according to the present invention. It is a flowchart which shows the procedure. 1... To S2 record, 1A to 1D... Recording head, 14... Recovery device, 20... Control unit, 21... CPU, 22... ROM. 23...RAM, 24, 25.26...driver, 100...ink discharge port, 200...electrothermal converter, 300...liquid path. 200 to Kukimugi 18Ki 1 East, 2 Douni, 2F Kiuke 9ru: To Kakaru Kiren~, Dokoni no) n f'
Figure 2 Figure 4

Claims (1)

[Scope of Claims] 1) Each of the plurality of recording heads includes an ink ejection port and an ejection energy generating means provided in a liquid path communicating with the ink ejection port for ejecting ink from the ejection port. In an inkjet recording apparatus that is capable of performing recording by ejecting ink having different characteristics from each of the recording heads, and performing idle ejection of ejecting ink by driving the ejection energy generating means during a recovery operation, An inkjet recording apparatus comprising means for setting conditions for driving the ejection energy generating means for ejection according to characteristics of the ink. 2) The characteristics of the ink are related to the dye concentration of the ink, and the condition for driving the ejection energy generating means for the idle ejection is the number of drive pulses supplied for the idle ejection. The inkjet recording apparatus according to claim 1, characterized in that: 3) The conditions for driving the ejection energy generating means, which are set according to the characteristics of the ink, are set in accordance with the history of ink ejection using the ink performed for recording. Item 2. The inkjet recording device according to item 1 or 2.