JPH03184872A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To reduce consumption of ink by a construction wherein a means for detecting the state of a device is provided, and in accordance with the state, the action timings of an ink pressurizing pump and a valve are controlled at the time of ink circulation for controlling a pressurizing force. CONSTITUTION:A recorder is constructed so that in accordance with the state of the recorder, such as the quiescent time of the recorder and the temperature of a recording head, three types of circulation recovery actions, i.e. modes A, B, and C, can be executed in required sequences. In the mode A which is operated when a power source is ON, a circulation time is 0.5sec. and during this period a solenoid valve 7 is closed for 0.3sec. to set a pressurizing force acting to a delivery port 2a higher than that in the mode B. The mode B has a sequence that a circulation time is set to 0.5sec. and the solenoid valve 7 has been opened before a recovery pump 10 is operated. In the mode C, an action timing is controlled with a sequence that a circulation time is 1.5sec. and during this period the solenoid valve 7 is closed for 0.5sec. In this manner, the wasteful consumption of ink at the time of recovery can be minimized with a simple mechanism.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to copying machines, facsimile machines, word processors,
The present invention relates to a liquid jet recording device used in a computer output printer, a video printer, etc., and more particularly to a liquid jet recording device provided with a recovery means for resolving ejection failure caused by ejection port clogging or the like.

[Prior Art] Recording devices such as printers, copying machines, and printers record images consisting of dot patterns on recording media such as paper or thin plastic plates based on transferred image information. It is composed of

The recording device can be divided into liquid jet type, wire dot type, thermal type, laser beam type, etc. according to the recording method, among which liquid jet type (liquid jet recording device)
is a liquid such as ink (recording liquid) from the ejection port of the print head.
The printer is configured to eject and fly the ink so that it adheres to a recording medium (generally, a recording sheet such as paper or a thin plastic plate is used) for recording.

In this liquid jet recording apparatus, problems arise such as clogging of the ejection ports of the print head and ejection failure due to increased ink viscosity during liquid jet recording.

Therefore, as a countermeasure to this problem, recovery means for discharging ink using a suction method or a pressurized circulation method has been considered and is already known.

[Technical problem to be solved by the invention] However,
Conventional suction-based recovery means have complicated mechanisms and have problems in terms of efficiency and ability of recovery operations.

In particular, in the case of liquid jet recording using a recording head with a large number of ejection ports aimed at high speed, even if the large number of ejection ports are suctioned at once, the liquid mainly flows out from the ejection ports that are not clogged, so recovery is difficult. ability will decrease. Therefore, when trying to solve such problems, the mechanism becomes complicated.

On the other hand, in the case of the recovery means using the pressurized circulation method, it is easy to strengthen the pressurizing force and is suitable for recovery of a print head having a large number of ejection ports, but on the other hand, it has the problem of high ink consumption. Ta.

In addition, if the pressure is increased to improve the recovery effect, the thin film structure is likely to be damaged and the life of the recording head will be shortened if at least part of the liquid path that has an ejection energy generating means is made by thin film molding, such as in a bubble jet type. There was a fear that this would cause problems with durability, such as shrinkage.

The present invention has been made in view of the above technical problems, and with a simple mechanism, it is possible to minimize wasteful ink consumption during recovery, and to shorten the time required for recovery operation. Moreover, it is an object of the present invention to provide a liquid jet recording apparatus that can improve the life of a recording head.

[Means to solve the problem]

The present invention provides a circulating supply means having an ink pressurizing pump and a valve in a supply path connecting a recording head and an ink tank;
A liquid jet recording apparatus comprising means for controlling the opening and closing of the valve, and for forming an image by ejecting and flying droplets from an ejection port of the recording head and depositing the droplets on a recording medium,
It is equipped with means for detecting the state of the device, and according to the state, controls the operation timing of the ink pressurizing pump and valve during ink circulation according to the state, thereby controlling the pressurizing force with a simple mechanism. To provide a liquid jet recording device that can minimize wasteful ink consumption during recovery, shorten the time required for recovery operation, and improve the life of the recording head. .

The invention as claimed in claim 2 provides a structure in which, in the above configuration, the state described in claim I is the time when the recording device is left, thereby further efficiently shortening the time required for the recovery operation and improving the life of the recording head. The present invention provides a liquid jet recording device that is capable of achieving high performance.

The invention as claimed in claim 3 provides, in the above configuration, that the state of the apparatus according to claim 1 is the temperature of the recording head, thereby further efficiently shortening the time required for recovery operation and improving the life of the recording head. The present invention provides a liquid jet recording device that can achieve the following.

〔Example] Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of a liquid supply and circulation system to a recording head of a liquid jet recording apparatus according to the present invention.

In FIG. 1, a main tank 1 and a recording head 2 are connected through a circulation pipe 3, and a recovery valve 4 and a replenishment valve 5 are connected to predetermined positions of the circulation pipe 3.

Moreover, between the recovery valve 4 and the replenishment valve 5 of the circulation pipe 3,
One end of the supply pipe 6 is connected to the recording head 2, and the other end of the supply pipe 6 is connected to the recording head 2.

At a predetermined position of this supply pipe 6, a solenoid valve 7 and a liquid tank 9 are provided.
and recovery pump 10 are connected.

The liquid tank 9 is provided with an air vent valve 8 that opens into a space above the liquid level.

The recording head 2 is provided with a large number of ejection ports 2a and a common liquid chamber 2b, and each ejection port 2a is communicated with the common liquid chamber 2b through a liquid path.

The large number of ejection ports 2a are formed in a predetermined arrangement on the front surface (ejection port surface) 2c of the recording head 2.

During normal recording, the recovery valve 4 and the replenishment valve 5 are closed, the solenoid valve 7 is opened, the liquid from the liquid tank 9 is supplied to the recording head 2 (common liquid chamber 2b), and the liquid is discharged from each discharge port 2a. An energy generator is driven to eject and fly droplets to record an image.

When the level in the liquid tank 9 falls below a standard, the replenishment valve 5 is opened and the pump 10 is operated to replenish the liquid in the main tank into the liquid tank.

During the recovery operation, the recovery valve 4 is closed with the replenishment valve 5 closed.
By opening the solenoid valve 7 and operating the recovery pump 10, the liquid in the liquid tank 9 is transferred from the supply pipe 6 to the recording head 2 (common liquid chamber 2b) to the circulation pipe 3 to the pump 10-+.
The liquid is circulated under pressure through the liquid tank 9.

During this pressurized circulation, most of the liquid is returned from the circulation pipe 3 to the liquid tank 9, but some of the liquid is returned to the ejection port 2 of the recording head 2.
It also flows out from a.

Due to the liquid flowing out from the discharge port 2a, the discharge port 2a
Foreign matter or thickened ink that is clogged inside (inside the liquid path) is removed from the ejection port 2a.
The recording head 2 is pushed out and the recording head 2 is cleaned, thereby maintaining an optimal recording state.

FIG. 2 is a flowchart of the operation of the liquid supply and circulation system in FIG. 1, and FIG. 3 illustrates the sequence of three types of circulation recovery modes A, B, and C performed during the operation of FIG. 2. This is a time chart.

In FIG. 2, when the power is turned on, mode A circulation recovery is started in step 31, and in step S2,
The recording head 2 is camped to seal the ejection port surface 2c, and each ejection port 2a is immersed in the liquid absorbed by the liquid absorber in the closed space for a predetermined period of time, thereby dissolving the stuck substances.

In step S3, it is determined whether or not the fixed matter dissolution time has reached a set value, and after the set time has elapsed, a copy start is performed in step S4, and the process proceeds to step S5 to perform idle ejection.

Next, in step S6, the recording head 2 is set at the recording position (head down), and recording is performed in step S7.

Even during the recording operation, the state of the recording device is detected in step S8 to determine whether or not a predetermined time interval set for performing a recovery operation has elapsed, and if the predetermined time has elapsed, the state of the recording device is detected in step S9. The recording head 2 is raised in step S10, and a mode B circulation recovery operation is executed.

After this mode B recovery operation, the process returns to step S5 and the recording operation is resumed.

If it is determined in step S8 that the state of the recording device is such that the recovery time has not yet been reached, step S3
Proceeding to step 11, it is determined whether or not it is a copy end (CopyEnd).

If it is not the copy end, the process returns to step S7 to continue recording; if it is the copy end, the process proceeds to step 312 to determine whether the recovery switch is on or off.

If the recovery switch is on, the head is raised in step S13, and then the process proceeds to step 314 to execute the circulation recovery operation in mode C. After completing this recovery operation, the process returns to step S2 to perform the operations in each of the aforementioned steps. Execute repeatedly.

On the other hand, if the recovery switch is off in step SL2,
The process advances to step S15 to start copying, and returns to step S7 to continue the recording.

In the liquid jet recording apparatus of the present invention, the state of the recording apparatus, that is, the time the recording apparatus has been left unused, the temperature of the recording head, etc., is detected, and the ink pressurizing pump 10 and the valve By controlling the operation timing of (electromagnetic valve) 7, ink pressurizing force (for example,
The pressurizing force applied to the discharge port 2a is controlled.

That is, it is configured to be able to appropriately execute the three types of circulation recovery operations in modes A, B, and C in a desired sequence depending on the state of the printing apparatus, such as the length of time the printing apparatus has been left unused and the temperature of the print head. ing.

Here, the aforementioned three circulation recovery operation modes A, B, and C will be explained.

FIG. 3A is a time chart of the operation of the recovery pump 1o and the solenoid valve 7 in the mode.

Mode A is a mode that operates when the power is turned on, and this mode is operated quite frequently.

Therefore, in mode A, the amount of liquid consumed is important, and liquid circulation cannot be continued for too long.

However, liquid sticking may occur if left for a long time, so even if the time is about the same as mode B described below,
If the contents remain the same, the recovery ability will be insufficient.

Therefore, as shown in the time chart in Figure 3 (A), the circulation time is 0.5 seconds, but 0.3 seconds
The solenoid valve 7 is kept closed for a second, and the pressurizing force acting on the discharge port 2a is increased from mode B.

That is, by controlling the drive time of the pump 10 and the opening/closing time of the solenoid valve 17, that is, the operation timing of the ink pressurizing pump 10 and the solenoid valve 7 for adjusting the circulation flow rate, liquid is supplied under pressure to the recording head 2. The pressurizing force and pressurizing time are controlled.

FIG. 3(B) is a time chart of the operation of the recovery pump 10 and the solenoid valve 7 in mode B.

This mode B is a sequence to prevent ejection ports that do not eject droplets during continuous recording from failing due to increased liquid viscosity, etc., so it operates quickly and reduces liquid consumption. It is desirable to have the least amount compared to .

Furthermore, mode B is expected to be used more frequently than other modes, so if the life of the recording head 2 is considered, the circulation pressure (pressure force) should be lowered to reduce the burden on the recording head 2. It is desirable to reduce this as much as possible.

Based on the above conditions, in the illustrated example, mode B has a circulation time of 0. The sequence is set to 5 seconds and the solenoid valve 7 is opened before the recovery pump 10 is activated.

Also in this mode B, by controlling the drive time of the pump 1o and the opening/closing time of the electromagnetic valve 7, the pressurizing force and pressurizing time when pressurizing and supplying the liquid to the recording head 2 are controlled.

FIG. 3(C) is a time chart of the operation of the recovery pump 1o and the solenoid valve 7 in mode C.

This mode C is a mode that is not normally performed.

In liquid jet recording devices, ejection port clogging (ejection failure due to increased liquid viscosity, foreign matter clogging, wetting of the ejection port surface, etc.) is an unavoidable problem, and must be dealt with.

Therefore, this mode C circulation recovery operation was prepared.

This mode C is operated when an ejection failure or an ejection port with a large droplet landing error occurs depending on the output image (ejection frequency of each ejection port), and the frequency of operation is quite low.

Therefore, for the purpose of use, in mode C, recovery ability is more important than the amount of liquid consumed or the length of operation time.

Therefore, in the illustrated example, mode C has a circulation time of 1.5
seconds, of which 0. The operation timing is controlled by a sequence in which the solenoid valve 7 is closed for 5 seconds.

In this mode C as well, by controlling the driving time of the pump 10 and the opening/closing time of the electromagnetic valve 7, the pressurizing force and pressurizing time when pressurizing and supplying the liquid to the recording head 2 are controlled.

Note that the circulating pressure of the liquid is mode A1 mode B.

Both mode C and 2. Ice/sec is set, and approximately 10% of the circulating liquid is discharged from the discharge port 2a.

It is not necessary to execute all of the three recovery operation modes A, B, and C in the recording operation shown in FIG. 2, and they can be appropriately selected and executed depending on the state of the recording apparatus.

The effect obtained by circulating the liquid (recording liquid such as ink) is not limited to cleaning the ejection ports described above, but can also be used as a means for regulating the temperature te1 of the recording head 2.

For example, in the case of a recording apparatus that adjusts the temperature of the recording head 2 and maintains it at a constant temperature, the effect of temperature adjustment can be obtained not only by a heater and a fan but also by liquid circulation.

In that case, the temperature of the recording head 2 is detected by the temperature detection means to determine the state of the recording apparatus, and the operation timing of the ink pressurizing pump 10 and the electromagnetic valve 7 is adjusted depending on the state during ink circulation. This control controls the pressurizing force and pressurizing time when supplying the liquid to the recording head 2 under pressure.

Hereinafter, as an example of the control operation of the ink pressurizing force according to the temperature of the recording head, a case where the temperature of the recording head 2 is adjusted to 50 degrees Celsius, which is suitable for a stable ejection device, will be described. The sequence will be explained.

The target printing apparatus has an A4 long width printing head, and is equipped with a heater and a fan as temperature control means for the printing head.

However, when high-density recording is performed continuously, the temperature may rise excessively with fan cooling alone.

Therefore, when the temperature of the recording head 2 exceeds a set value, the recording head 2 is cooled by circulating the liquid instead of blowing air from the fan.

In the case of this recording apparatus, a cycle of about 0.5 seconds is sufficient to lower the temperature of the recording head 2 by I'C at room temperature.

Also, at that time, room temperature liquid (recording liquid such as ink) rapidly flows into the high temperature recording head 2, so the ejection ports 2
In order to reduce the burden on a as much as possible, the solenoid valve 7 (Fig. 1)
It is preferable to leave it open.

In this example, when controlling the temperature at 50°C,
If you start driving only the fan cooling at 1"C, the maximum is 5
In systems where the temperature rises to 5°C, the maximum temperature can be increased to 53°C by combining circulation of room temperature liquid for 0°5 seconds at 52°C.
I was able to keep it down to

In this way, by controlling the temperature of the liquid circulation, the temperature of the recording head 2 during pressurization can be controlled.

6. FIG. 4 is a sectional view showing the recording head 2 capped with a cap 20 suitable for implementing the present invention.

The recording head 2 in FIG. 4 is a full-color recording head, etc.
A case is shown in which a plurality of (four in the illustrated example) recording heads are camped.

In FIG. 4, the recording head 2 is camped in a sealed state using a porous absorbing material 11 and a sealing material 12 dedicated to each color, and a sealed space formed in front of the ejection port surface 2c is filled with liquid (recording liquid). By filling with vapor pressure of , liquid (ink) is prevented from sticking on the ejection port surface 2c.

However, if the device is left unused for a long period of time (several months or more), the liquid may solidify and the normal recovery mode may not be able to perform properly, or the normal recovery mode may exceed its specifications.

Therefore, a timer was attached to the recording device, and three circulation recovery modes were provided corresponding to three cases: 1 month to 6 months, 6 months or more, and 1 month or less.

7 FIG. 5 is a time chart of the three circulation recovery modes.

In Fig. 5, (a) shows mode I, which is activated when it has been left unused for one month, (b) shows mode ■, which is activated when it has been left unused for one to six months, and (c) is mode Indicates the mode ■ that will be activated if the device is left unused for more than a month.

Mode I in FIG. 5 is the same as mode B in FIG.

Mode ■ in FIG. 5 has a circulation time of 1.5 in mode I.
This time was doubled to 0.75 seconds.

In addition, in mode (2) in FIG. 5, which is used when the absorbent material is left for six months or more, there is a possibility that the moisture in the porous absorbent body 11 in FIG. 4 dries or becomes dirty.

Therefore, in advance, the porous absorbent body is wetted during the first liquid circulation, and as much liquid (recording liquid) as possible is used to wash away foreign substances.

In general, when a porous absorbent material dries, its moisture absorption ability decreases and its hardness increases. Therefore, if the ejection port surface 2c (Fig. It may cause injury.

Therefore, during long-term storage, the recording state recovery effect is improved by sufficiently circulating the liquid to allow the porous absorbent body 11 to absorb the liquid and then performing the normal recovery operation again.

In the embodiment described above, as shown in the time charts of FIGS. 3 and 5, the pump IO during liquid circulation is
By controlling the drive time and the opening/closing of the electromagnetic valve 7, the pressurizing force and pressurizing time when supplying liquid under pressure to the recording head 2 are controlled.

Further, the temperature of the recording head 2 is controlled by controlling the temperature of the pressurized circulation of the liquid by using it in combination with a conventional temperature control means such as a heater or a fan, or by using it alone.

In this way, as shown in FIG. 2, three circulation recovery modes, mode A, mode B, and mode C, are incorporated into the control operation of the recording apparatus, and the sequence of each circulation recovery mode is set for the purpose of ejection recovery. , 9, or depending on the state of the liquid jet recording head immediately before the recovery operation, the environmental temperature and humidity, etc., pressurize the recording head 2 (pressurizing force and pressurizing time when liquid is supplied, and the recording head 2 during pressurization). Since the configuration is configured so that at least one of the temperatures of the recording head can be controlled, wasteful liquid consumption during the recovery operation can be reduced, recovery time can be shortened, and the recovery operation can be performed efficiently. A liquid jet recording device has been obtained that can improve the lifespan of the device.

[Effects of the Invention] As is clear from the above description, according to the invention of claim 1, there is provided a circulating supply means having an ink pressurizing pump and a valve in the supply path connecting the recording head and the ink tank, and a method for opening and closing the valve. A liquid jet recording apparatus that forms an image by ejecting and flying droplets from an ejection port of the recording head and depositing the droplets on a recording medium, the liquid jet recording apparatus comprising: a means for detecting a state of the apparatus. According to the state, the pressurizing force is controlled by controlling the operation timing of the ink pressurizing pump and valve during ink circulation, so the simple mechanism eliminates wasted ink during recovery. A liquid jet recording apparatus is provided that can minimize consumption, shorten the time required for a recovery operation, and improve the life of the recording head.

According to the invention of claim 2, in the above configuration, the invention of claim 1
Since the state described in 1. is configured such that the recording apparatus is left unused, a liquid jet recording apparatus is provided that can more efficiently shorten the time required for a recovery operation and improve the life of the recording head.

According to the invention of claim 3, in the above configuration, claim 1
Since the state of the apparatus described in 1 is configured to be the temperature of the recording head, a liquid jet recording apparatus is provided which can more efficiently shorten the time required for a recovery operation and improve the life of the recording head.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a device for supplying and circulating liquid in a liquid jet recording apparatus according to the present invention, FIG. 2 is a flowchart showing the operation of the device in FIG. 1, and FIG. A time chart illustrating sequence 1 of the circulation recovery mode, FIG. 4 is a longitudinal sectional view showing a structure suitable as a capping means for the recording head of the liquid jet recording apparatus of FIGS. 1 to 3, and FIG. 3 is a time chart showing three examples of circulation recovery sequences after long-term storage in a liquid jet recording device according to the present invention. 2... Recording head, 2a...
...Discharge port, 3... Circulation pipe,
6...... Supply pipe, 7... Solenoid valve, 9... Liquid tank, 10...
...Recovery pump, 20...Capping means.

Claims (3)

[Claims] (1) A circulation supply means having an ink pressurizing pump and a valve in the supply path connecting the recording head and the ink tank, and a means for controlling the opening and closing of the valve, and droplets are ejected from the discharge port of the recording head. A liquid jet recording device that forms an image by ejecting jet and adhering it to a recording medium is equipped with means for detecting the state of the device, and depending on the state, the ink pressurizing pump and valve are adjusted during ink circulation. A liquid jet recording device characterized by controlling pressurizing force by controlling actuation timing. (2) The liquid jet recording apparatus according to claim 1, wherein the state according to claim 1 is a standing time of the recording apparatus. (3) The liquid jet recording apparatus according to claim 1, wherein the state of the apparatus according to claim 1 is the temperature of the recording head.