JPH0292548A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To remove generation of discharge inferiority of a liquid drop by a method wherein a means which counts standby time is provided in an ink jet recording device and said means is so constructed as to perform recovery operation of a recording head when a specific elapsed time has elapsed. CONSTITUTION:A power source is supplied to an power source part 9, and a carriage 22 on which a recording head 21 is mounted is moved to a home position H to perform initial operations such as resetting or the like of various counters or the like. A timer 104 is reset and counting is started. An operation panel 5 selects on line and judges whether printing is performed on recording paper P or not by inputting recording data via an interface circuit 4. In the case of negation judgement, a state of the operation panel 5 is read and whether recovery operation of the recording head 21 is selected or not is judged. When selected, the recovery operation of the recording head 21 is performed. In the case of negative judgement, whether the timer 104 counts up or not is judged. When counting up of the timer is detected, the recovery operation of the recording head is performed. When the counting up of the timer 104 is not detected, the recording data are inputted via the interface circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink jet recording apparatus having a recovery device for preventing clogging of a recording head.

[Prior Art] Conventionally, a liquid jet recording method (inkjet recording method) is known in which recording is performed by ejecting a recording liquid and making it fly γJ1. This method has excellent features such as high-speed printing, low noise, high recording quality, easy recording of color images, and the ability to record on plain paper.

An inkjet recording device used in such an inkjet recording method generally includes a liquid ejection opening (orifice) for ejecting the recording liquid as droplets;
An inkjet recording head having a liquid flow path (nozzle) communicating with the orifice, and an ejection energy generating means provided in a part of the nozzle to apply ejection energy to the recording liquid in the nozzle to form flying droplets. We are prepared.

Recording is performed by driving the ejection energy generating means to supply ejection energy to the recording liquid in the nozzle, ejecting the recording liquid as flying droplets from the orifice, and making these droplets land on the recording medium. be.

The recording liquid used when recording with such an inkjet recording device generally consists of a recording agent such as a pigment or dye, and mainly water, or water and a water-soluble organic solvent or a water-soluble organic solvent for dissolving or dispersing it. It is formed by a non-aqueous solvent and a solvent component consisting of a non-aqueous solvent. In an inkjet recording device, an orifice provided at the tip of a nozzle through which recording liquid is ejected is often constantly open to the outside air of the device, regardless of whether or not the device is being driven. Therefore, if recording is not performed for a long period of time, some of the solvent evaporates from the orifice into the outside air, and recording agent components and solvent components that are difficult to volatilize remain in the recording liquid. The composition of the recording liquid stagnant in the nozzle portion changes and the viscosity increases, resulting in an increase in the viscous resistance of the nozzle portion. Therefore, immediately after restarting recording after the printing material has stopped, droplet ejection failure is likely to occur, in which droplets are not ejected even though the ejection signal is applied.
There is a problem in that defects occur in the initial printed portion of the recorded image.

In conventional inkjet recording devices, it is detected whether or not an ejection failure has occurred in the print head, and depending on the detection, recovery processing is performed by driving the print head (dry ejection) or forced ejection of ink due to pressurization or suction. In some cases, there are difficulties in implementing a configuration that performs recovery processing in terms of equipment methods and configuration costs. Therefore, for example, by automatically performing recording head recovery processing every time the power is turned on, it is possible to reliably record on the recording medium from the time the power is turned on, and the recording head is capped during standby to increase ink liquid. There are products designed to prevent stickiness, etc. according to this,
Printing defects are less likely to occur when recording is performed again after waiting for a while.

[Problem to be solved by the invention]

However, in such an inkjet recording device, even if the recording head is capped during standby, if the device is left on standby for a long time, the recording agent component of the ink may cause the ink to stagnate as the recording head cools down. In some cases, recording agent components may be deposited near the opening of the recording head.

Therefore, if printing is performed on a recording medium after the apparatus has been on standby for a long period of time, printing defects may occur and stable recording may not be possible.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an inkjet recording apparatus that eliminates the above-mentioned conventional problems and is capable of performing good and stable recording without causing droplet ejection failure even after being left for a long time.

(Means for Solving the Problems) In order to achieve such an object, the present invention includes a method for ejecting ink droplets from a recording head onto a recording surface of a recording medium,
An inkjet recording apparatus that performs recording includes: a timer for measuring the standby time of the apparatus; a determining means for determining that the standby time has exceeded a set time; and a recovery means for performing a recovery operation of the recording head in accordance with the determination. It is characterized by having the following.

[For production]

According to the present invention, the inkjet recording apparatus is provided with a means for measuring standby time, and is configured to perform a recovery operation of the recording head when the predetermined standby time has elapsed. Good and stable recording becomes possible.

〔Example〕

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

FIG. 1 is a perspective view showing the configuration of the main parts of an inkjet recording apparatus to which the present invention is applicable. Here, reference numeral 21 denotes a recording head (liquid ejecting) mounted on a carriage 22 and provided with a nozzle portion for ejecting liquid in a sink. This recording head 2
1 can be provided, for example, in four pieces as shown in the figure, depending on the ink color. A cartridge tank serving as an ink supply source can be attached to the carriage 22. 23 is a printed wiring board that controls ink ejection by the recording head 2I, 24 is a flexible cable that connects the printed wiring board 23 and the recording head 21, and the printed wiring board 23 and the flexible cable 24 are connected via a connector. do. Reference numeral 25 denotes a paper feed motor, and as the paper feed motor 25 is driven, the recording paper P is conveyed by a roller 26 in the direction f in the figure. A roller 27 cooperates with the roller 26 to flatten the recording paper P and form a recording surface for the recording head 21.

28 is a carriage driving belt connected to the carriage 22, 29 is a motor that drives the belt 28 in the S direction in the figure, and 30 is a guide rail for the carriage 22.

The carriage 22 can move along the guide rail 30 in the S direction in the figure in accordance with the drive of the motor 29, and can perform recording on the recording surface.

Further, reference numeral 31 denotes a recovery device that faces the recording head 21 at the home position H of the recording head 21 and performs a recovery operation of the recording head.

Examples will be described in detail below, but the same parts will be given the same reference numerals and the explanation thereof will be omitted.

Embodiment 1 FIG. 2 is a block diagram showing an embodiment of the present invention. The recording head 21 is mounted on a carriage, and this carriage is driven by a motor 29 along the recording paper P in the direction S in FIG. The recording paper P is conveyed in the direction S in FIG. 1 by the roller 27 in accordance with the drive of the paper feed motor 25.

Thereby, two-dimensional scanning by the recording head 21 is performed. At this time, the recording head 21 performs recording on the recording paper P by flying ink droplets under the control of the control unit 1. Monthly section 1 part 1 is microprocessor unit (MPU)
, a ROM 102 in which a program corresponding to the processing procedure described later with reference to FIG. It is composed of an output boat 105. The recording head 21, the motor 29, and the paper feed motor 25 are provided with a human power boat 10.
Control data is provided via 5.

In addition, the interface circuit 4 is connected from the host device (not shown).
The recorded data is manually input through the . The inkjet recording apparatus of the present invention can be controlled not only through the host device but also through the operation panel 5. Furthermore, the presence or absence of the recording paper P and the home position RH of the carriage 22 are detected by the sensor 6. The power supply section 9 supplies power to each device.
It is carried out by The recording head recovery device performs an automatic recovery operation when the cap of the recording head 21 during standby and the recording head becomes clogged.

Here, the automatic recovery operation refers to, for example, removing air bubbles and dust by sealing the area around the orifice of the recording head and suctioning and recovering the recording liquid using negative pressure. Not limited. For example, the ink may be discharged by pressurizing the ink supply system, or the ink may be discharged by driving four columns during recording.

The recovery operation of the recording head 21 is normally performed when the power is turned on and when the recovery operation is selected on the operation panel 5, but in this example, it is also started during standby.

FIG. 3 is a flowchart showing the processing procedure of the first embodiment of the present invention shown in FIG.

Now, in step 51, power is supplied to the power supply section 9! Raw or supplied. In step S2, the carriage 22 carrying the recording head 21 is moved to the home position H, and initial operations such as resetting various counters are performed. In step S3, a recovery operation of the recording head 21 is performed.

Next, in step S4, the timer 104 is reset and starts counting. In step S5, it is determined whether online is selected on the operation panel 5 and whether the recorded data is to be manually printed on the recording paper P via the interface circuit 4. If the determination in step S5 is affirmative, the process proceeds to step s6 and printing is performed on the recording paper P.

If the determination in step S5 is negative, the process proceeds to step S8, where the state of the operation panel 5 is read and it is determined whether the operation panel 5 has been operated and the recovery operation of the recording head 21 has been selected. If the determination in step S8 is affirmative, it means that the recovery operation has been selected by the operation panel 5, so the process returns to step S3 and the recovery operation of the recording head 21 is performed.

If a negative determination is made in step S8, no command has been given from the operation panel 5, so it is determined in step S9 whether or not the timer 104 is counting up.

When the count-up of the timer is detected in step S9, it means that a predetermined time has elapsed due to the previous recovery operation or the end of printing, so the process returns to step S3 and the recording head recovery operation is performed.

If the count-up of the timer 104 is not detected in step S9, the process returns to step S5.

Finally, in step S7, it is determined whether printing has ended. If it is determined in step S7 that printing has ended, the apparatus enters a standby state, returns to step S4, resets the timer 104, and restarts.

On the other hand, if it is determined in step S7 that printing has not been completed, the process returns to step S6 and printing is resumed.

To summarize, in the tree embodiment, the timer 104 counts the time since the recording head recovery operation was performed or the time since printing was completed. and,
If the recording head recovery operation or printing is not performed within a predetermined time, the recording head recovery operation is performed.

Embodiment 2 FIG. 4 is a block diagram showing the configuration of a second embodiment of the present invention. In FIG. 4, the configuration is the same as that of the block diagram shown in FIG. 2, except that a dip switch 10 is provided for setting the standby time counted by a timer 104. Here, if the dip switch has 2 bits, four states (ie, standby time) can be set.

FIG. 5 is a flowchart showing the processing procedure of the second embodiment of the present invention shown in FIG.

First, power is supplied to the power supply unit 9 in step SIO. In step Sll, the carriage 22 carrying the recording head 21 is moved to the home position H, and initial operations such as resetting various counters are performed.

In step 512, the setting state of the dip switch IO is read, and in step 519, which will be described later, the timer 1 is set.
Set the waiting time for counting 04. If you use a 2-bit dip switch, you can select four stages of standby time.

In step 513, a recovery operation of the recording head 21 is performed. Then, in step 514, timer 10
4 and start counting. In step 515, the operation panel 5 has selected online, and the recording data is manually input to the recording paper P via the interface circuit 4.
Determine whether or not to print.

If the determination is affirmative in step 515, step 5
Proceed to step 16 and print on recording paper P. If a negative determination is made in step 515, the process advances to step 518, and the operation panel 5
The state of the recording head 2 is read, the operation panel 5 is operated, and the recording head 2 is
It is determined whether the recovery operation No. 1 is selected. If an affirmative determination is made in step 518, this means that the recovery operation has been selected using the operation panel 5, so the process returns to step S+3 and the recovery operation of the recording head 21 is performed.

If the determination in step 51B is negative, no command has been given from the operation panel 5, so in step S19 it is determined whether or not the timer 104 is counting up. When the count-up of the timer 104 is detected in step 519, it means that a predetermined time has elapsed due to the previous recovery operation or completion of printing, so the process returns to step 513 and performs the recording head recovery operation.

If the count-up of the timer 104 is not detected in step 519, the process returns to step 515.

Finally, in step 517, it is determined whether printing has ended. If it is determined in step S17 that printing has ended, the apparatus enters a standby state, returns to step S, resets the timer 104, and restarts. Step 517
If it is determined in step 51 that printing has not been completed, the process returns to step 516 and printing is resumed.

Embodiment 3 One of the reasons for changing the standby time for performing the recovery operation of the recording head is the operating environment of the inkjet recording apparatus. FIG. 6 is a characteristic diagram showing the relationship between temperature and humidity.

Various types of inkjet recording devices are known. For example, in an inkjet recording device using an electrothermal converter as an ejection energy generating element, when the temperature rises, the temperature inside the recording head becomes higher than normal. As the bubble rises and its size changes, outside air is taken into the orifice, and when ink is ejected, a state in which there is no ink in the orifice occurs. Furthermore, when the humidity is high, paper dust from recording paper tends to adhere to the ejection openings of the recording head, causing clogging. Therefore, region C is not preferred. On the other hand, region B is not preferable because the viscosity of the ink liquid increases as the temperature and humidity decrease. From the above considerations, area A
In area B or area C, clogging of the recording head is more likely to occur. Therefore, in the case of area B or area C, it is better to make the standby time for performing the recording head recovery operation shorter than in the case of area A.

In this embodiment, the standby time for the recording head recovery operation is made variable by detecting the temperature and humidity of the operating environment.

FIG. 7 is a block diagram showing the configuration of a third embodiment of the present invention.

FIG. 7 shows the temperature sensor 11 in the block diagram shown in FIG.
The configuration is the same except that a humidity sensor 12 is provided.

FIG. 8 is a flowchart showing the processing procedure of the block diagram shown in FIG.

First, in step 520, power is simultaneously supplied to the power supply unit 9. In step 521, the carriage 22 carrying the recording head 21 is moved to the home position H, and initial operations such as resetting various counters are performed. Step 52
2, a recovery operation of the recording head 21 is performed.

In step S23, the memory area of the RAM 103 that stores data on standby time is cleared and the initial value is reset, and in step S24, the timer 104 is reset to start counting. In step S25, it is determined whether the operation panel 5 has selected online and whether or not the recording data is to be manually printed on the recording paper P via the interface circuit 4.

If the determination is affirmative in step S25, step S2
Proceed to step 6 to print. If a negative determination is made in step S25, the process proceeds to step 528, where the state of the operation panel 5 is read and it is determined whether the operation panel 5 has been operated and a recovery operation for the recording head 21 has been selected. Step 528
If the determination is affirmative, this means that the recovery operation has been selected using the operation panel 5, so the process returns to step S22 and the recording head recovery operation is performed.

If the determination in step 528 is negative, the operation panel 5
Since no command is given from the controller, the temperature and humidity are detected in step S29, and based on the data, it is determined in which region the operating environment is.

In step 530, the standby time data of simple and old 03 is adjusted depending on the area determined in step S29. For example, when the determined environment is in area B in FIG. 6, the waiting time data in the RAM 103 is reduced.

In the next step S31, the value of the standby time stored in the RAM 103 and the value of the timer 104 are compared to determine whether or not the time for performing a recovery operation of the recording head has been reached. If the determination in step 531 is affirmative, the process advances to step S22 and a recording head recovery operation is performed. If the determination in step 531 is negative, resetting of the timer 104 is started. Finally, in step S27, it is determined whether printing has ended. If it is determined in step S27 that printing has ended, the apparatus enters a standby state, returns to step S23, and initializes the standby time. If it is determined in step S27 that printing has not been completed, the process returns to step 52B and printing is resumed.

Embodiment 4 In Embodiments 1 to 3, the recording head recovers when it is in a standby state for a predetermined period of time or longer, so that the recording head is always free from clogging. However, if the device is in standby mode for a very long time, the recovery operation will be performed many times. In one recovery operation, only a small amount of ink is consumed due to suction or the like, but if these operations overlap, a large amount of ink will end up being wasted.

This embodiment is configured to suppress this ink waste.

FIG. 9 is a flowchart showing the processing procedure of the fourth embodiment of the present invention.

First, in step S33, power is simultaneously supplied to the power supply section 9. In step 534, the carriage 22 carrying the recording head 21 is moved to the home position H, and initial operations such as resetting various counters are performed. Step 53
5, a recovery operation of the recording head 2 is performed.

Next, in step S36, the timer 104 is reset and starts counting.

In step S37, it is determined whether the operation panel 5 has selected online and whether or not the recording data is to be manually printed on the recording paper P via the interface circuit 4. When printing is started in step S31, the timer 104 determines whether or not the time for performing the recording head recovery operation has passed in the subsequent step 538. If the time has not yet reached in step 53B, printing is started as is (step 539). If the time has exceeded, a recording head recovery operation is performed in step S42, and then printing is started (step 539).
.

If the determination is negative in step S37, step 54
1, the state of the operation panel 5 is read and it is determined whether the operation panel 5 has been operated and the recovery operation for the recording head 2 has been selected. If the determination in step 541 is affirmative, it means that the recovery operation has been selected by the operation panel 5, so the process returns to step S35 and the recovery operation of the recording head 21 is performed.

If a negative determination is made in step 541, since no command has been given from the operation panel 5, the process returns to step S37.

Finally, in step S40, it is determined whether printing has ended. If it is determined in step 540 that printing has ended, the apparatus enters a standby state, returns to step S36, resets the timer 104, and restarts. If it is determined in step S40 that printing has not been completed, the process returns to step S39 and printing is resumed.

In this embodiment, the recovery operation is not performed even when it is time for the recording head to recover, and the recovery operation is performed immediately before starting the next printing, so that wasteful consumption of ink can be suppressed.

(Effects of the Invention) As described above, according to the present invention, the inkjet recording apparatus is provided with means for measuring standby time, and is configured to perform the recording head recovery operation after a predetermined time has elapsed. The effect was obtained that good and stable recording was possible without causing droplet ejection failure due to clogging.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of the main parts of an inkjet recording apparatus to which the present invention can be applied, FIG. 2 is a block diagram showing the first embodiment of the present invention, and FIG. 3 is the same as shown in FIG. 2. FIG. 4 is a block diagram showing the second embodiment of the present invention; FIG. 5 is a flowchart showing the processing procedure of the embodiment of the present invention shown in FIG. 4. , FIG. 6 is a characteristic diagram showing the relationship between temperature and humidity, which is the operating environment of the inkjet recording device, FIG. 7 is a block diagram showing the third embodiment of the present invention, and FIG. 8 is shown in FIG. FIG. 9 is a flowchart showing the processing procedure of the fourth embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Control part, 4...Interface circuit, 5...Operation panel, 6...Sensor, 9...Electronic source, lO...Dip switch, 11...Temperature sensor, 12... Temperature sensor, 21... (liquid jet) recording head, 22... Carriage, 23... Printed wiring board, 24... Flexible cable, 25... Paper feed motor, 28.27 ... Roller, 28 ... Belt, 29 ... Motor, 30 ... Guide rail, 31 ... Recovery device, 101 ... Micro flow processor unit 102 ... R
OM, 103...RAM. 104...Timer, 105...Man output boat. (h+pu) Figure 1 Figure 3 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1) An inkjet recording device that performs recording by ejecting ink droplets from a recording head onto a recording surface of a recording medium, comprising: a timer for measuring a standby time of the device; An inkjet recording apparatus comprising: a determination means for determining whether a set time has been exceeded; and a recovery means for performing a recovery operation of the recording head in response to the determination.