JPS60104338A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To make it possible to certainly correspond to the trouble of a nozzle, by providing a spare nozzle corresponding to a main nozzle and adjusting drive timing only for a scanning time corresponding to the distance from the main nozzle when the spare nozzle is driven. CONSTITUTION:At the time of normality, an emission signal change-over device 4 selects main nozzles 2A-2D and a desired dot is formed while a head 1 is scanned to a direction shown by the arrow corresponding to the signal from a head driver 3. Herein, for example, when emission inferiority is generated in the main nozzle 2B and detected by an emission abnormality detector 6, the emission signal change-over device 4 selects a spare nozzle 2B' and drive timing is delayed only for a scanning time corresponding to the distance between the nozzles 2B, 2B' set to a delay circuit 5 and the drive pulse from the driver 3 is applied. By this method, the interruption or prolongation of recording work is prevented even if trouble is generated in the nozzle and the nozzle is restored from trouble and certain recording operation is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an inkjet recording device, and more particularly to an inkjet recording device that performs recording by ejecting ink droplets from nozzles.

[Prior Art] Generally, in an inkjet head of an inkjet recording device, the diameter of the nozzle is lfilogm, and failure to eject ink droplets may occur due to clogging of the nozzle due to dust or generation of air bubbles. Since the inkjet recording apparatus is provided with only the minimum number of nozzles necessary, there is a drawback that if any one of the nozzles fails to eject, it will result in a recording failure.

In addition, mechanisms have been proposed to recover the clogged nozzles as described above by manually or automatically pumping ink or suctioning ink from the ejection ports, but such mechanisms prolong recording time and Otherwise, the recording operation is interrupted, which is inconvenient when recording work is being done in a hurry.

Furthermore, if a clogging or failure occurs that cannot be recovered using this recovery mechanism, the nozzle must be replaced, but in most inkjet recording devices, it is often impossible to replace individual nozzles. In most cases, the inkjet head is replaced as an assembly. Therefore, if even a single nozzle develops an irrecoverable failure, the entire expensive head assembly must be replaced, placing a heavy burden on the user.

[Purpose] The present invention has been made in view of the following two points.With a simple and inexpensive structure, even if trouble occurs with the nozzle, the recording operation will not be interrupted or prolonged. It is an object of the present invention to provide a highly reliable inkjet recording device Vq that can recover from nozzle trouble and perform reliable recording operations.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 and FIG. 2 show an embodiment of an inkjet recording apparatus of the present invention. Here, a so-called head scanning type inkjet recording apparatus in which an inkjet head is moved to scan a recording medium is used as an embodiment.

FIG. 1 shows a front view of an inkjet head 1 of an infusiera I recording apparatus of the present invention, and this inkjet head 1 has four main nozzles 28 to 2D, which are indicated by arrows in the figure. They are arranged at predetermined intervals along the main scanning direction of the head l. Further, corresponding to each of these main nozzles, preliminary nozzles 2A' to 2D' are arranged at a predetermined pressure glIIs from each of the main nozzles 2A to 2D.

That is, each preliminary nozzle is arranged in the main scanning direction, that is, in the head transport direction with respect to the corresponding main nozzle.

Each nozzle shown in FIG. 1 is configured to be driven by a known ejection energy generating means such as a piezo element or a heating element to eject ink droplets, but this ejection drive is performed as shown in FIG. This is done by a control circuit.

That is, the head driver 3 generates a drive pulse for driving each nozzle in response to a drive signal applied from the outside, and the drive pulse is transmitted to the main nozzles 28 to 2D or the spare nozzle 2A' by the ejection signal switcher 4. ~2D
', and then sent to the inkjet.
Each nozzle is driven to eject. The head dryer/driver 3 can be mainly composed of switching transistors, and the ejection signal switch 4 can be composed of a microcomputer, a discrete logic circuit, and a gate circuit or a switch circuit.

A known ejection abnormality detector 6 that mainly detects ink ejection failure is provided near the inkjet head l, and the output of this ejection abnormality detector 6 is sent to an ejection signal switch 4.
will be given feedback.

Unless an ejection failure is detected by the ejection abnormality detector 6, the ejection signal switching device 4 performs a recording operation using the main nozzles 2A to 2D, and the ejection abnormality detector 6 detects an ink ejection failure. If this occurs, the ejection signal switch 4 switches the output signal line to drive the spare nozzle corresponding to the main nozzle in which the trouble has occurred.

Furthermore, a delay circuit 5 is attached to the discharge signal switch 4, and the discharge signal switch 4 is connected to the spare nozzle 2A'.
When driving ~2D', the drive pulse is delayed by the time specified by the delay circuit 5. This delay time is set equal to the time required for the inkjet head 1 to move the distance between one set of main nozzles and the spare nozzle, depending on the scanning speed of the inkjet head 1.

The operation in the above configuration is performed as follows.

During the recording operation, the head driver 3 generates drive pulses necessary to drive each nozzle of the inkjet head 1 in response to drive signals applied from the outside as described above.

Unless an ejection failure such as non-ejection is detected by the ejection abnormality detector 6, the ejection signal switch 4 switches between the main nozzles 28 and 28.
A necessary nozzle is selected from 2D and recorded. At this time, the inkjet head 1 scans in the direction of the arrow in FIG. 1, and at this time, each of the main nozzles 2A to 2D is driven one after the other at a predetermined timing to eject ink onto the recording medium, forming a desired dot. .

When the ejection abnormality detector 6 detects that an ejection failure has occurred in any of the nozzles, a spare nozzle corresponding to the main nozzle that has caused the ejection failure is selected and driven instead.

For example, when the main nozzle 2B causes a discharge failure and a detection signal is sent from the discharge abnormality detector 6 to the discharge signal switch 4, the discharge signal switch 4 switches the output signal line to select the spare nozzle 2B'. Ru. This allows the main nozzle 2
A driving pulse is now applied to the preliminary nozzle 2B' instead of B, but at this time, the driving pulse to the preliminary nozzle 2B' is delayed by the time set in the delay circuit 5 and applied.

This delay allows the Kiku main nozzle 2B to perform discharge.

If the configuration is configured with redundancy in the number of nozzles as described above, it is possible to drive the corresponding spare nozzle in the event that a problem occurs with any of the main nozzles that are regularly used, and in that case, the main nozzle can also be activated. Since the preliminary nozzle is driven with a delay of the scanning time of the inkjet head corresponding to the interval between the nozzle and the preliminary nozzle, it is possible to reliably perform dot recording at the same desired position as that recorded by the main nozzle.

This switching can be done instantaneously, and there is no need to interrupt the recording operation and perform a recovery operation as in the conventional method, which saves recording time. In addition, even if one nozzle has a fatal failure, the spare nozzle can be continued to be used, and there is no need to immediately replace the assembly, which is expensive as in the past, reducing the burden on the user. I can do it.

In the above embodiment, there are 4 main nozzles and 4 spare nozzles.
Although the number of nozzles is set for each tree, it may be configured so that all four trees eject ink of the same color, or the four trees each have different inks, such as yellow, magenta, cyan, and black. Color recording may be performed by allocating and ejecting four colors of ink such as .

Further, the discharge abnormality detector 6 shown in the above embodiment may be omitted. In this case, the ejection signal switch 4 may be configured as 41 using a dip switch or the like so that the operator can manually switch the signal line to the inkjet head 1 when a recording failure occurs.

Furthermore, even without providing a delay circuit, if the spare nozzles are arranged in the main scanning direction, if the main nozzle prints first, then when the main nozzle becomes in a droplet non-discharge state IE, it can be done immediately. By switching the signal to the spare nozzle corresponding to the main nozzle, there is almost no deterioration in image quality.

In the above embodiments, the main nozzle is arranged in the main scanning direction, that is, in the direction of the feed/nozzle transfer, and a spare nozzle is provided in the main scanning direction for each of the main nozzles. The nozzles may be arranged in a direction different from the main scanning direction (perpendicular in this example), and a spare nozzle may be provided for each direction. Further, as shown in FIG. 1, the spare nozzles do not have to be provided near the corresponding main nozzles.

For example, in the example of FIG. 1, the main and spare nozzles may be distributed among the eight nozzles shown, such as four on the right and four on the left. Alternatively, the four nozzles in the center may be used as main nozzles, and the two on the outside may be used as backup nozzles. When configured in this way, the scanning width of the head does not necessarily need to be such that the entire head covers the recording width on the recording medium, but the main or spare nozzles currently in use are arranged so as to cover a predetermined recording width. Just do it.

Further, the present invention can be used in a so-called full-line multi-head inkjet recording device in which nozzles are provided across the entire scanning width, and inkjet recording devices in which the head is fixed and the recording medium is transported.

Furthermore, the number of spare nozzles should not be limited to one at a time, but many more, Takunobu 11! Of course, the interval j may be set at several levels.

[Effects] As is clear from the explanation below, according to the present invention, in an inkjet recording apparatus that performs recording by ejecting ink droplets from nozzles, at least one spare nozzle is provided corresponding to each main nozzle. and a means for selecting and driving either the main or spare nozzle by switching the drive signal, and a scanning time corresponding to the distance from the main nozzle to the spare nozzle when driving the spare nozzle. Since the configuration is equipped with a means to adjust the drive timing of the spare nozzle, even if trouble occurs with the nozzle, the simple and inexpensive configuration does not interrupt or prolong the recording process. It is possible to provide an excellent and highly reliable inkjet recording apparatus that can recover from nozzle trouble and perform reliable recording operations.

[Brief explanation of the drawing]

FIG. 1 is a diagram of an inkjet head used in the inkjet recording apparatus of the present invention, FIG. 2 is a block diagram of the drive control circuit of the inkjet recording apparatus of the present invention, and FIG.
The figure is an IF view showing still another embodiment of the inkjet head of the present invention. 1... Inkjet head 2A to 2D... Main nozzle 2A' to 2D'... Spare nozzle 3... Head driver 4... Ejection signal switcher 5... Delay circuit 6... Ejection abnormality Detector patent applicant Canon Corporation

Claims (2)

[Claims] (1) In an inkjet recording device that performs recording by ejecting ink droplets from a nozzle, there is a means for selecting and driving either a main nozzle or a spare nozzle, and a means for driving a main nozzle that corresponds to the main nozzle when driving a spare nozzle. An inkjet recording apparatus characterized by comprising means for adjusting drive timing of a spare nozzle by a scanning time corresponding to a distance to the spare nozzle. (2) A defective ink ejection detection means is provided, and when the detection means detects an ejection defect, the switching means switches the drive signal from the main nozzle to the spare nozzle. The inkjet recording device according to item 1.