JP3113123B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet apparatus which forms flying liquid droplets by discharging liquid from an orifice and performs recording using the flying liquid droplets, and more particularly, to a recovery device for preventing clogging. The present invention relates to an inkjet recording apparatus provided.

[0002]

2. Description of the Related Art In an ink jet recording method, ink (recording liquid) is ejected from an orifice provided in a recording head.
This is a recording method in which recording is performed by adhering this to a recording material such as paper, in which noise generation is extremely low, high-speed recording is possible, and there is no need to use recording paper of a special configuration. Therefore, various types of recording heads have been developed.

[0003] In such an ink jet recording method, high-speed recording has been increasingly demanded in recent years, and is one of the main developments at present.

In order to enable high-speed printing, one of measures is to reduce the flow resistance of the ink and increase the ejection frequency of the ink, and to increase the number of orifices for ejecting the ink. Now, both of these are being done a lot. However, although the recording speed can be increased by increasing the number of orifices, various problems occur.

The ink jet recording head has a fine orifice for discharging ink, and has a drawback that the orifice is easily clogged. For this reason, ink supply systems and recovery devices for preventing clogging have been developed. Clogging reasons ink water aqueous evaporates from the orifice <br/> as increased ink viscosity orifice near
A state in which ejection is not possible is mentioned.

For this reason, an operation of discharging ink having increased viscosity from an orifice is performed. The discharge operation includes what is called circulation recovery and suction recovery.

In the circulation recovery, ink is sent from an ink tank to a common liquid chamber of a head by a pump, and the ink is returned to the ink tank. At this time, the ink pushes out the ink having the increased viscosity from the orifice, and the ink can be ejected. The ink discharged from the orifice is sent to a discharged ink reservoir through a cap. Although a high pressure difference can be obtained because the ink is pressurized and high reliability can be obtained, there is a problem that the apparatus becomes large and the cost increases.

[0008] Suction recovery is a recovery device that applies a negative pressure through a cap by a suction pump and directly discharges ink from an orifice. It has the advantage that the device is small and the cost is low, but because the recovery operation is performed using reduced pressure, if the number of orifices increases, the amount of ink flowing out of the orifice increases, and less pressure is applied to the desired place, There is a problem that the recovery performance differs depending on the position of the orifice.

[0009]

Among the above-mentioned discharge operations, there is a problem that the apparatus is large and the cost is high for the circulation recovery, and the recovery performance differs depending on the position of the orifice in the suction recovery. There is.

In view of the above, an object of the present invention is to provide an ink jet recording apparatus which is inexpensive and has a highly reliable recovery device even for an ink jet head having an increased number of orifices.

[0011]

An ink jet recording apparatus according to the present invention comprises an ink jet head having a plurality of orifices for discharging ink, and a plurality of orifices for sucking and discharging ink from the plurality of orifices. In an ink jet recording apparatus provided with a suction cap to cover, at least one second suction cap provided inside the suction cap, and at the time of suction and discharge, suction and discharge are performed by the suction cap and then suction by only the second suction cap is performed. And a control mechanism for performing discharge.

In this case, a suction cap that covers all of the plurality of orifices and at least one or more second suction caps provided in the cap may be integrally formed.

[0013]

When performing a recovery operation by suction only with a suction cap covering all of the plurality of orifices, there are orifices that are difficult to recover, and the location is fixed depending on the position of the ink supply port. Therefore, if a suction system that increases the suction capacity is formed at this position, a highly reliable recovery operation can be realized.

In the present invention, by providing the second suction cap at a position corresponding to the orifice which is difficult to recover, the ink of the orifice which could not be discharged by suction discharge to all of the plurality of orifices is suctioned by the second suction cap. Since the discharge operation is performed, the recovery operation is more reliable.

Further, by forming a suction system with a large suction capacity in a suction cap covering all of the plurality of orifices, the capping operation (the movement of the cap during the recovery operation) and the mechanism can be simplified. Become.

[0016]

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

(Embodiment 1) FIG. 1 is a perspective view showing the structure of a bubble jet type ink jet head used in this embodiment.

The ink jet head shown in FIG.
It has 512 orifices 202 formed with an orifice density of DPI (partially omitted). Bonding the substrate 2 and the top plate 3 made of glass, to form a nozzle 201 which is part of the ink channel therebetween. The top plate 3 ink reservoir called the common liquid chamber 6 is made of glass at the rear of the nozzle 201
It is formed by excavating. The common liquid chamber 6 has ink supply ports at both ends of the head, and supplies ink to the orifice rows from both sides.

FIG. 2A is a cross-sectional view showing the configuration of the head configured as described above and a cap that covers the orifice array provided on the head, and FIG. 2B is a side view thereof.

The head 1 has a substrate 2, a top plate 3, and a common liquid chamber 6 configured in the same manner as shown in FIG. These are mounted on a base plate 4 and supported by a cap contact member 5.

The cap covering the head 1 configured as described above, the cap 7 for sucking covering all of the orifices 202 as shown in FIG., The central portion of the inner orifice array of the cap 7 for the suction only A small cap 8 (second suction cap) is provided at a position that covers. The cap 8 is connected to a pipe 11 and is thereby connected to a suction pump (not shown). The small cap 8 and the large cap 7 are configured so as not to leak through the O-ring 9, and a spring coil 10 constituting a control mechanism is provided between the large cap 7 and the pipe 11. Position adjustments have been made.

Next, the operation of this embodiment will be described.

When a suction operation is started, the head 1 moves so as to face the position where the cap is provided. The cap is moved upward by a motor (not shown).
Is pushed up. Thereafter, the large cap 7 comes into contact with the head 1 and the suction pump reduces the pressure. At this time, the ink having the increased viscosity is discharged from the orifice. But,
Since ink is supplied from both sides of the orifice row, bubbles may easily remain at the center of the orifice row in this state, and there may be cases where the ink cannot be recovered satisfactorily.

The pipe 11 then slowly rises,
Push up the small cap 8. When the small cap 8 comes into contact with the orifice row, the pressure reducing capability of the suction pump concentrates on the center of the orifice row, and the remaining bubbles and the like are sucked by the small cap 8. In this embodiment, a cylinder and a piston are used for the pump, and when the large cap 7 comes into contact with the head 1, the cylinder is started to move, and when the small cap 8 starts to come into contact, suction is started again (the pump itself is used for suction). 2 cycles).

According to this embodiment, even when the ink was initially filled into the head, no bubbles or the like remained even in the recovery operation, and a good print state was exhibited.

(Embodiment 2) FIG. 3 is a perspective view showing a structure of an ink jet head of a bubble jet system used in this embodiment.

With an orifice density of 300 DPI,
It has 56 orifices. The substrate 402 and the glass top plate 403 are bonded to each other, and the nozzles 31 that are a part of the ink flow path are formed therebetween as in the first embodiment. Behind the nozzle 31, a common liquid chamber 40 is provided.
The ink reservoir referred to as 6 is formed in a way to push drilling the glass top plate 403, not shown for clarity in FIG. The common liquid chamber 406 has an ink supply port 46 at the center of the head, and supplies ink from the center of the orifice row.

FIG. 4A is a cross-sectional view showing the structure of the head having the above-described structure and a cap for covering the orifice array provided on the head, and FIG. 4B is a side view thereof.

The head 401 includes a substrate 402, a top plate 403, and a common liquid chamber 4 which are configured in the same manner as shown in FIG.
06. These are mounted on a base plate 404 and supported by a cap contact member 405.

The cap covering the head 401 configured as described above, a small cap 408 covering only the ends of the orifice array to the inside of the suction cap 407 covering all orifices as shown in Figure 4 (second Suction cap)
Are arranged. The pipe 41 is attached to the cap 408.
1 is connected and connected to a suction pump (not shown). Small cap 408 and large cap 407
Is configured so that there is no leak through the O-ring 409. A spring coil 410 constituting a control mechanism is provided between the large cap 407 and the pipe 411, and the position between them is adjusted.

Next, the operation of this embodiment will be described.

When the suction operation is started, the head moves so as to face each other at the position where the cap is provided. The cap is pushed up by a pipe 411 upward in the figure by a motor (not shown). Thereafter, the large cap 407 contacts the head, and the suction pump reduces the pressure. At this time, the ink having the increased viscosity is discharged from the orifice. However, since the ink is supplied from the center of the orifice row, bubbles are likely to remain at both ends of the orifice row, and there are cases where recovery cannot be performed well. The pipe 411 then slowly rises, pushing up the small cap 408.
When the small cap 408 comes into contact with the orifice row, the pressure reducing capability of the suction pump is concentrated at both ends of the orifice row, and the remaining bubbles and the like are sucked by the small cap 408. In this embodiment, a diaphragm pump is used as the pump. According to the present embodiment, even when the ink was initially filled into the head, no bubbles or the like remained even in the recovery operation, and a good print state was exhibited.

(Embodiment 3) FIG. 5 is a sectional view showing a main part of a third embodiment of the present invention, and FIG. 5 (a) is a diagram showing a state at the initial stage of a recovery operation. (B) is a figure which shows the state of the latter half of a recovery operation.

In the cap used in this embodiment, a first cap portion 507 covering all of the plurality of orifices and a second cap portion 508 covering only the central portion of the plurality of orifices are made of one piece of rubber. Things. Other configurations are the same as those shown in FIG.

First cap portion 507 and second cap portion 5
Reference numeral 08 is made of one piece of rubber, and has a small thickness at the center of the bottom surface of the second cap portion 508 so that it is easily deformed. At the time of the recovery operation, as in the first embodiment, the center portion of the cap is pushed, and the first cap portion 507 comes into contact with the head. Here the suction pump is activated,
Start suction and start discharging ink from the orifice. Further, the center portion of the cap is pressed, and the rubber is deformed, so that the second cap portion 508 covering the center portion of the orifice row contacts the head. At this time, the first cap portion 507 has been deformed, has started to leak, and has returned to the atmospheric pressure. For this reason, suction is performed only at the center of the orifice, and the bubbles and the like remaining at the center of the orifice are completely discharged.

In this embodiment, the same head as in the first embodiment was used, and the recoverability was good. However, since the first cap portion 507 is at atmospheric pressure, if the diameter of the orifice is too large, air may be sucked from the orifices at both ends while ink is being sucked from the central orifice. . In this case, the rigidity of the rubber may be increased to prevent leakage even when the second cap portion 508 at the center contacts the head.

The present invention provides an excellent effect particularly in an ink jet recording head and a recording apparatus in which a flying liquid droplet is formed by utilizing thermal energy in the ink jet recording method and recording is performed.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or liquid path in which This is effective because heat energy is generated in the electrothermal transducer, causing film boiling on the heat-acting surface of the recording head, and as a result, air bubbles in the liquid (ink) corresponding one-to-one to this drive signal can be formed. It is. 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 a 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 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angle liquid flow path) as disclosed in the above-mentioned respective specifications, The present invention also includes a configuration using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which a heat acting portion is arranged in a bending region.

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, or absorbs pressure waves of thermal energy. The present invention is also effective as a configuration based on JP-A-59-138461, which discloses a configuration in which an opening corresponds 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 is determined by combining a plurality of recording heads as disclosed in the above specification. The present invention can exhibit the above-mentioned effects more effectively, though it may be either a configuration that satisfies the above requirements or a configuration as a single recording head that is formed integrally.

In addition, the print head is replaceable with a print head of a chip type which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention is also effective when a cartridge type recording head provided with an ink tank is used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like provided as components of the printing apparatus of the present invention since the effects of the present invention can be further stabilized. If you list these specifically,
Capping means, cleaning means, pressurizing or suction means for the printhead, preheating means using an electrothermal transducer or another heating element or a combination thereof, and a preliminary ejection mode for performing ejection other than recording Is also effective for performing stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black. The recording head may be integrally formed or a plurality of recording heads may be combined. The present invention is also extremely effective for an apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or below and which softens at room temperature or is liquid, In general, in the ink jet method, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range. What is necessary is just to be liquid.

In addition, the temperature rise due to the heat energy is positively prevented by using it as energy for changing the state of the ink from the solid state to the liquid state, or the ink is solidified in a standing state for the purpose of preventing evaporation of the ink. Either ink may be used, or in any case, the ink may be liquefied by application of heat energy according to the recording signal and ejected as a liquid ink, or may already start to solidify when reaching the recording medium. The use of ink having a property of being liquefied for the first time by heat energy is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5684.
No. 7 or Japanese Patent Application Laid-Open No. 60-71260, in which the porous sheet is opposed to the electrothermal converter while being held in a liquid or solid state in the concave portions or through holes of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be provided as an image output terminal of an information processing apparatus such as a word processor or a computer as an integrated or separate image output terminal, a copying apparatus combined with a reader or the like, May take the form of a facsimile machine having a transmission / reception function.

[0049]

According to the present invention, suction recovery, which is an inexpensive recovery method in an ink jet recording method, is employed, and a cap covering a part of an orifice is disposed in all the caps covering a plurality of orifices. The operation of the cap is simple (one direction in this embodiment), and there is an effect that an ink jet recording apparatus having a highly reliable and inexpensive recovery device can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a head used in first and third embodiments of the present invention.

FIG. 2 is an explanatory diagram of a cap according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a head used in a second embodiment of the present invention.

FIG. 4 is an explanatory view of a cap according to a second embodiment of the present invention.

FIG. 5 is an explanatory view of a cap according to a third embodiment of the present invention.

[Explanation of symbols]

 1,401 Head 2,402 Substrate 3,403 Top plate 4,404 Base plate 5,405 Cap contact member 6,406 Supply liquid chamber 7,8,407,408 Cap 9,409 O-ring 10,410 Coil 11,411 pipe 31,201 nozzle 202 orifice 507 first cap 508 second cap

Claims (2)

(57) [Claims] 1. An ink jet recording apparatus comprising: an ink jet head having a plurality of orifices for discharging ink; and a suction cap covering all of the plurality of orifices for sucking and discharging ink from the plurality of orifices. A second suction cap provided at least one or more inside the suction cap; and a control mechanism for performing suction and discharge only by the second suction cap after performing suction and discharge by the suction cap at the time of suction and discharge. An ink jet recording apparatus comprising: 2. The ink jet recording apparatus according to claim 1, wherein a suction cap that covers all of the plurality of orifices and at least one or more second suction caps provided in the cap are integrally formed. An ink jet recording apparatus comprising: