JP2814283B2 - Recovery method for inkjet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recovery method for an inkjet recording apparatus that performs recording by discharging ink onto a recording material.

[Conventional technology]

2. Description of the Related Art A recording device such as a printer, a copying machine, and a facsimile is configured to record an image formed of a dot pattern on a recording material such as paper or a plastic thin plate based on image information.

The recording device can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method. Among them, the ink jet type (ink jet recording device) discharges ink onto a recording material to perform recording. Is performed.

The ink jet recording apparatus has advantages such as low noise since it is a non-impact method, and it is easy to record a color image using multicolor inks.

However, in the inkjet recording device, recording is performed by directly discharging ink from the fine discharge port of the recording head, so special means not seen in other methods is required to keep the ink always dischargeable It is.

For example, during printing, foreign matter such as ink droplets or paper fluff due to ink mist adheres to the ejection port surface, causing ejection failure.In the case of the serial scan method, a wiper blade is provided on the apparatus main body side and the recording head is provided. A cleaning operation such as wiping the discharge port surface using the movement is performed.

Further, in addition to the serial scan method, a line method having a recording head covering substantially the entire width of a recording material is configured to operate a recovery unit at a predetermined time.

[Technical problem to be solved by the invention]

However, in the above prior art, the change in the amount of ink mist generated due to the change in the temperature of the recording head was not taken into account, so the ejection amount increased due to the decrease in the ink viscosity due to the temperature rise of the recording head during recording. When the mist increases, there is a technical problem that it is difficult to sufficiently recover the discharge function by the set recovery operation at a fixed time interval.

The present invention has been made in view of the above technical problem, and an object of the present invention is to realize a quick recovery while suppressing a decrease in recording speed and an increase in ink consumption even during recording. It is an object of the present invention to provide a recovery method for an ink jet printing apparatus that can perform accurate restart printing easily without causing discontinuity in a printed image.

[Means for solving the problem]

2. An ink jet recording apparatus according to claim 1, further comprising a carriage mounted with a recording head for ejecting ink and moving, and ejecting ink from said recording head onto a recording material to perform recording. A first recovery step of recovering the recording head when the apparatus is powered on or before recording by the recording head, and after the step, starting recording by starting recording by the recording head. A step of determining whether or not the temperature of the recording head has reached a predetermined temperature after the step; and determining that the temperature of the recording head has reached the predetermined temperature in the step. A second recovery step of terminating the recording of the line being moved and recording, and thereafter recovering an operation time shorter than the recovery operation time in the first recovery step. And wherein the Mukoto.

〔Example〕

 Hereinafter, the present invention will be specifically described with reference to the drawings.

Embodiment 1 FIG. 1 is a perspective view schematically showing a configuration of a main part of an ink jet recording apparatus suitable for performing a recovery method according to the present invention.

Hereinafter, a case where the present invention is applied to a bubble jet type ink jet recording apparatus will be described as an example.

In FIG. 1, reference numeral 1 denotes a recording unit mounted on a carriage 2, and the recording unit 1 has a bubble jet recording head 3 for performing recording with a plurality (four in the illustrated example) of thermal energy. ing.

Each recording head 3 is configured to apply a pulse voltage according to recording information to an electrothermal transducer such as a heating element, and to generate ink bubbles by thermal energy generated from the electrothermal transducer to eject ink. ing.

That is, each of the recording heads 3 is an ink jet recording head that discharges ink using thermal energy, and an electrothermal converter for generating thermal energy is disposed in a liquid path leading to each discharge port. It is a thing.

Further, each of the ink jet recording heads 3 performs recording by discharging ink from discharge by the growth of bubbles due to film boiling generated by the heat energy applied by the electrothermal transducer.

In the ink jet recording apparatus shown in FIG. 1, the recording unit 1 includes four recording heads 3A, 3B, 3C, and 3D, each of which can correspond to, for example, yellow, magenta, cyan, and black.

Reference numeral 13 denotes a recording material transport motor, 12 denotes a transport roller driven by the motor 13 to transport the recording material P in the direction of arrow f, and 14 denotes a recording material P in cooperation with the roller 12. Is a roller for forming a recording surface for the recording unit 1 while keeping the recording surface flat.

During recording, the recording material P is transported at a predetermined pitch in the direction of arrow f each time recording of one line is completed.

Further, 15 is a carriage driving belt connected to the carriage 2, 16 is a carriage motor for driving the belt 15 in the direction of arrow S, and 18 is a guide shaft for guiding and supporting the carriage 2.

That is, the carriage 2 reciprocates in the arrow S direction along the guide shaft 18 according to the rotation of the motor 16,
The recording on the recording surface can be performed by driving the recording unit 1 in synchronization with the movement.

FIG. 2 is a perspective view schematically showing a configuration of the plurality of recording heads 3A to 3D mounted on the carriage 2 in FIG.

1 and 2, reference numeral 21 denotes each of the recording heads 3A to 3A.
A supply pipe for supplying each ink to 3D, a return pipe 22 for returning ink from each of the recording heads 3A to 3D to the ink tank 23,
Further, reference numeral 24 denotes a non-discharge recovery device for recovering the discharge state of each recording head 3.

The non-discharge recovery device 24 is disposed at a position where the recording head 3 faces when the carriage 2 reaches the home position H. 3 is used to eliminate non-discharge.

In FIG. 2, each of the recording heads 3A to 3D has a temperature detecting means 4A, 4B for detecting the temperature of the recording head.
4C, 4D and a heater 5A for heating the recording head,
5B, 5C, 5D are attached.

As the temperature detecting means 4A to 4D, for example, a temperature IC, a thermistor, a thermocouple, a varistor, or the like can be used.

Further, as the heater 5, for example, a power transistor or a heating element can be used.

The temperature detected by each of the temperature detecting means 4A to 4D is supplied to a temperature control device, and the on / off of each of the heaters 5A to 5D is controlled so that the temperature of each of the recording heads 3A to 3D is maintained at a set temperature. Controlled.

FIG. 3 is a schematic diagram showing a schematic configuration of a pressure recovery system of the ink jet recording apparatus of FIG.

FIG. 3 shows a state where the sealing member of the non-discharge recovery device 24 is brought into close contact with the discharge port surface of the recording head 3 at the home position H, and the discharge port 31 is sealed.

In FIG. 3, the ink closet 23 and the common liquid chamber 30 of the recording head 3 correspond to the ink supply pipe 21 and the ink return pipe.
A recovery pump 25 is provided in the middle of the ink supply pipe 21 as an ink pressure feeding means.

Reference numeral 32 in FIG. 3 denotes an electrothermal converter such as a heating element for generating thermal energy for discharge disposed in each liquid path connecting the common liquid chamber 30 and each discharge port 31. Show body.

 Next, the non-discharge recovery operation will be described.

In the ink jet recording apparatus, when the temperature of the recording head 3 rises, there is a phenomenon that the viscosity of the ink decreases and the ink ejection amount increases.

At that time, as the ink ejection amount increases, ink mist is likely to be generated, the ink mist adheres to the ejection port surface, and the ejection port is blocked by the adhered droplets, so that ejection failure easily occurs.

FIG. 4 shows the recording head temperature and the recording head temperature when recording is performed at a driving frequency of 3 kHz and a recording ratio of 75% in a bubble jet type inkjet recording head having a discharge port density of 400 dpi and 128 discharge ports. 9 is a graph showing a relationship with the number of ejection failures.

As shown in FIG. 4, the temperature of the recording head 3 is 40 ° C.
At 〜60 ° C., the number of non-ejections occurring is about twice that at 30 ° C. to 40 ° C.

FIG. 5 is a flowchart showing a sequence of a recovery operation of a recovery method of an ink jet recording apparatus as a reference example on which the present invention is based.

In FIG. 5, when a recording operation is started in step S101, temperature detection of the recording head 3 by the temperature detecting means 4 is started, and in step S102, the temperature of the recording head 3 is set to a set temperature (50 ° C. in this example). It is determined whether or not the recording has been reached, and when the temperature reaches the set temperature, in step S103, after the recording scan (recording of the line) is completed, the recording head 3 is returned to the home position H, and the recovery in FIG. The ink is pressurized and circulated along a system ink path, that is, an ink tank → ink supply pipe 21 → common liquid chamber 30 → ink return pipe 22 → ink tank 23 to recover ink ejection failure.

Then, the process returns to step S101 to start the recording scan again, and the above operation is repeated.

As described above, the above-described recovery operation is performed when the recording head temperature rises, which is the cause of the ejection failure, in order to prevent the ejection failure that easily occurs when the temperature of the recording head 3 rises during printing. , It is possible to prevent the image quality from being deteriorated due to the ejection failure.

As means for the recovery, in addition to the pressurizing and circulating mechanism as shown in FIG. 3, ink discharge by suction force, blowing of ink droplets on the discharge port surface by air, or on the discharge port surface by a wiper blade Various methods can be adopted as long as the purpose of recovery can be achieved, such as wiping of ink droplets.

FIG. 6 is a flowchart showing a recovery operation of an embodiment of the recovery method of the ink jet recording apparatus according to the present invention.

In FIG. 6, in step S201, a periodic recovery operation is performed with a pressurization time of 1 second, for example, at power-on or every recording, recording is started in step S202, and the recording head 3 is turned on in step S203. It is determined whether or not the temperature has reached a set temperature (50 ° C. in this embodiment). If the set temperature has been reached, in step S204, after the print scan (recording of the row) is completed, the print head 3 is returned to the home position H, and a recovery operation for a pressurization time of 0.1 second is performed.

The reason why the pressurizing time performed periodically is increased in this way is to eject the stuck foreign matter and the thickened ink prior to the start of printing, and the reason for shortening the pressurizing time performed during printing is as follows. This is because it only removes the wetting near the ejection port due to the ink mist and requires only a small amount of pressurization.

 This can save ink.

In another embodiment of the present invention, the timing of the recovery operation performed after the print scan can be changed according to the temperature of the print head 3.

For example, when the temperature of the recording head 3 is 30 ° C. to 40 ° C., one recovery operation is performed every third recording scan, and when the temperature of the recording head 3 is 40 ° C. to 50 ° C., the second recording scan is performed. One recovery operation is performed every time, and when the temperature of the recording head 3 is 50 ° C. or higher, control is performed so that one recovery operation is performed every scan.

According to such an embodiment as well, by changing the operating condition of the recovery operation in accordance with the temperature change of the recording head 3, it is possible to always perform an appropriate recovery operation, and to avoid wasteful consumption of ink. An ink jet recording apparatus capable of recording a stable high-quality image was obtained.

According to the recovery method of the ink jet recording apparatus as shown in FIG. 6, a deterioration in image quality is prevented by preventing a discharge failure due to an increase in the amount of ink mist generated due to a rise in the temperature of the recording head 3 during recording. Can do it, and
By reducing the operation time of the recovery operation of the second recovery step performed after the start of recording to be shorter than the operation time of the recovery operation of the first recovery step performed when the power is turned on or before the recording, a reduction in the recording speed can be prevented. Unnecessary consumption of ink can be eliminated.

Also, when the recording head reaches a predetermined temperature during recording,
After ending the recording of the line in the recording, the first
Since the second recovery process is performed for a shorter time than the recovery process of the first embodiment, a reliable recovery is performed by the first recovery process for a relatively long time before recording, and the second recovery process for a relatively short time is performed during recording. The second recovery step can realize a quick recovery while suppressing a decrease in recording speed and an increase in ink consumption, and perform the second recovery step after finishing the printing of the line in progress. Thus, accurate restart recording can be easily performed without causing discontinuity in the recorded image.

In the above embodiment, the present invention has been described by exemplifying a case where the present invention is applied to a serial type inkjet recording apparatus in which the recording head 3 is mounted on the carriage 2 and moves on the recording material P. The invention is also directed to an ink jet recording apparatus using a full multi-type recording head,
The present invention can be implemented in the same manner, and the same effect can be obtained.

Further, the present invention can be carried out irrespective of the number of recording heads, and can achieve the same function and effect.

The present invention particularly provides an excellent effect in an ink jet recording head of a bubble jet method among ink jet recording methods and an ink jet recording apparatus using the recording head.

The representative configuration and principle are preferably performed using the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796.

This method can be applied to any of the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged on a sheet or a liquid path holding a liquid (ink). By applying at least one drive signal to the electrothermal transducer, which corresponds to the recorded information and provides a rapid temperature rise exceeding nucleate boiling,
This is effective because thermal energy is generated in the electrothermal transducer, and the film is boiled on the heat-acting surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal.

By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed.

When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,434,262 are suitable.

Further, if the conditions described in US Pat. No. 4,313,124 relating to the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to the combination configuration (a linear liquid flow path or a right-angled liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in each of the above-mentioned specifications, a heat acting section A configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which the is bent, is also included in the present invention.

In addition, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure liquid of thermal energy. The present invention is also effective as a configuration based on JP-A-59-138461, which discloses a configuration in which is adapted to a discharge unit.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be reduced by a combination of a plurality of recording heads as disclosed in the above specification. Either a configuration that satisfies the above or a configuration as a single recording head that is integrally formed may be used, but the present invention can more effectively exert the above-described effects.

In addition, a replaceable chip-type recording head that can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body, or provided integrally with the recording head itself The present invention is also effective when a cartridge type recording head is used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like, which are provided as components of the printing apparatus of the present invention, since the effects of the present invention can be further stabilized.

If these are specifically mentioned, for the recording head,
Capping means, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof, and performing a predischarge mode in which discharge is performed separately from recording. Is also effective for performing stable recording.

Further, the printing mode of the printing apparatus is not limited to the printing mode of only the mainstream color such as black, but may be a printing head integrally formed or a combination of a plurality of printing heads. The present invention is extremely effective for an apparatus having at least one of the full colors.

In the embodiments of the present invention described above, the ink is described as a liquid, but the ink is solidified at room temperature or below, and is softened or liquid at room temperature, or the ink itself is 30 ° C. In general, the temperature is adjusted within a range of not more than ° C. and the temperature is controlled so that the viscosity of the ink is in a stable ejection range. Therefore, it is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, positively prevent temperature rise due to thermal energy as energy for changing the state of the ink from a solid state to a liquid state, or prevent ink that solidifies in a standing state to prevent evaporation of the ink. Or use
In any case, heat is first applied by heat energy, such as one in which ink is liquefied and ejected as an ink liquid by application in accordance with a recording signal of heat energy, and one which already starts to solidify when reaching a recording material. Use of an ink having a liquefying property is also applicable to the present invention.

In such a case, as in JP-A-54-56847, the ink is opposed to the electrothermal converter while being held as a liquid or a solid in the concave portions or through holes of the porous sheet. It is good also as a form.

In the present invention, the most effective one for the above-described ink is to execute the above-described film boiling method.

〔The invention's effect〕

As is apparent from the above description, according to the first aspect of the present invention, there is provided a carriage that is mounted and moves with a recording head that discharges ink, and performs recording by discharging ink from the recording head onto a recording material. A recovery method for an ink jet recording apparatus, comprising: a first recovery step of recovering the recording head when the apparatus is powered on or before recording by the recording head; and after the step, starting recording by the recording head. A recording start step to be performed; a determination step of determining whether or not the temperature of the recording head has reached a predetermined temperature after the step; and a determination that the temperature of the recording head has reached the predetermined temperature in the step. A second operation for terminating the recording of the line during which the carriage is moving and recording, and thereafter performing a recovery operation for a shorter operation time than the recovery operation time in the first recovery step. Therefore, before the recording, the first recovery step for a relatively long time ensures the recovery, and during the recording, the recording is performed by the second recovery step for a relatively short time. It is possible to realize a quick recovery while suppressing a decrease in the speed and an increase in the ink consumption, and further, by performing the second recovery step after finishing the printing of the row in progress, the discontinuity of the recorded image can be achieved. A method of recovering an ink jet recording apparatus capable of easily performing accurate restart recording without causing a problem.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a main configuration of an inkjet recording apparatus suitable for carrying out a recovery method according to the present invention,
2 is a perspective view showing details of a recording head of the ink jet recording apparatus of FIG. 1, FIG. 3 is a schematic diagram showing a schematic configuration of a pressure recovery system of the ink jet recording apparatus of FIG. 1, and FIG. FIG. 5 is a graph showing the relationship between the head temperature and the number of ejection failures, FIG. 5 is a flowchart of a recovery operation of a recovery method of an inkjet recording apparatus as a reference example on which the present invention is based, and FIG. 6 is a flowchart of a recovery operation of the device recovery method according to an embodiment. In the following, reference numerals indicating major components in the drawings are listed. 1 ... print head unit, 2 ... carriage, 3A-3D
...... printing head, 4 ... temperature detecting means, 5 ... heater,
21 ... ink supply pipe, 22 ... ink return pipe, 23 ... ink tank, 24 ... non-discharge recovery device, 25 ... ink pressure feeding means, 30 ... common liquid chamber, 31 ... discharge port, 32 ... ... Electrothermal transducer, P ... Recording material, S ... Recording head moving direction, f ...
... Recording material transport direction.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-10054 (JP, A) JP-A-61-206658 (JP, A) JP-A-61-249759 (JP, A) JP-A-61-249 266250 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 2/17

Claims (3)

(57) [Claims] 1. A method for recovering an ink jet recording apparatus, comprising: a carriage on which a recording head for discharging ink is mounted and moving, and recording by discharging ink from a recording head onto a recording material. A first recovery step of recovering the printhead at the time of power-on or before printing by the printhead; a printing start step of starting printing by the printhead after this step; A determining step of determining whether or not the temperature of the recording head has reached a predetermined temperature; and, if it is determined in this step that the temperature of the recording head has reached the predetermined temperature, the carriage is moved to perform recording. A second recovery step of terminating the recording of the middle line, and thereafter performing a recovery of an operation time shorter than the recovery operation time in the first recovery step. How to recover from jet recording apparatus. 2. The recording head according to claim 1, wherein the recording head is a recording head that discharges ink by using thermal energy, and is an ink jet recording head that includes an electrothermal converter for generating thermal energy. The method for recovering an ink jet recording apparatus according to claim 1. 3. A method for recovering an ink jet recording apparatus according to claim 2, wherein ink is ejected from an ejection port by growth of bubbles due to film boiling generated by thermal energy applied by said electrothermal transducer. .