JPH10181034A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the miniaturization and the reduction of cost of an ink jet recording device even when a longer multi-nozzle recording head is employed for high speed recording by a method wherein a pump, which develops a pressure change in a plurality of interior spaces, and valves, which are independently openable and closable, are provided under the condition that a plurality of discharging ports are covered with a cap. SOLUTION: In a recording head 1, a common liquid chamber communicating with respective nozzles 5, a filter unit 46 and an ink feeding unit 40 are provided. A suction cap 42, which is connected to a suction pump through an ink discharging tube 44, abuts through a sealing rubber 43 against the outside region of the discharging port surface of the recording head 1. Further, the sucking region of the suction cap 42 as a suction restoring means is divided into a plurality regions. Openable and closable valves 51a-51g as sucking action changing-over means are provided in the midways of ink sucking tubes 49a-49g as ink discharging courses between these divided regions and the pump 37 so as to perform necessary suction restoring actions by controlling the presence and absence of the sucking action of the recording head 1 for every sucking region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for performing an ejection recovery process for preventing and recovering from clogging at an ink ejection port of a recording head and defective ink ejection.

[0002]

2. Description of the Related Art In general, an ink jet recording head used in an ink jet recording apparatus has a discharge port for recording droplets, a nozzle for supplying a recording liquid to the discharge port, and energy provided in a part of the nozzle. There is provided an operating section and an energy generating means for generating energy for forming a droplet to act on the recording liquid in the operating section.

[0003] As this energy generating means, one using an electromechanical transducer such as a piezo element, irradiating an electromagnetic wave such as a laser and absorbing the liquid there to generate heat,
What discharges and flies droplets by the action of this heat generation, and a heating element such as an electrothermal converter are known.

In particular, an ink jet recording head which uses an electrothermal converter as an energy generating means and discharges recording droplets from discharge ports by thermal energy has the following advantages.

A) It is possible to easily arrange a discharge port for discharging recording droplets to form flying droplets at a high density, and easily adopt a structure suitable for performing recording with high resolution. It is possible.

B) It is easy to make the structure compact.

C) The advantages of IC technology and microfabrication technology, which have been remarkably improved in recent semiconductor technology and reliability in the field of fabrication, can be fully exploited. It is easier to form and planarize (two-dimensionally), multiply the number of discharge ports, and increase the density, and mass production is possible, and the manufacturing cost is low.

[0008] In an ink jet recording head having multiple discharge ports manufactured through a semiconductor manufacturing process using an electrothermal converter as an energy generating means, liquid paths corresponding to each discharge port are provided. An electrothermal converter is provided for each recording medium, and a recording liquid is supplied from a common liquid chamber communicating with each liquid path.

FIG. 10 schematically shows one configuration of such an ink jet recording head.

This ink-jet recording head is formed by an electrothermal converter 3, an electrode 4, a nozzle 5, a nozzle 5, and the like formed on a substrate 2 such as Si wear through semiconductor manufacturing process steps such as an etching method, a vapor deposition method, and a sputtering method. It is composed of a mounting board 15 such as a top plate 6Al.

The recording ink 12 is supplied from a liquid storage chamber (ink tank) (not shown) into the common liquid chamber 8 of the recording head 1 through an ink supply pipe 20. In the figure, reference numeral 9
Is a connector for an ink supply pipe.

The ink 12 supplied into the common liquid chamber 8 is supplied into the liquid path 10 by capillary action, and is stably held by forming a meniscus at the discharge port surface 11 at the tip of the liquid path.

When the electrothermal transducer 3 is energized, the recording liquid on the electrothermal transducer surface is heated, and a bubbling phenomenon occurs. Ink droplets are ejected from the ejection port surface 11 by the energy of the bubbling. .

With the above-described configuration, it is possible to manufacture a multi-nozzle ink jet recording head having 64 to 5000 nozzles in a high-density nozzle arrangement of 200 to 600 dpi.
With an inkjet recording apparatus using such an inkjet recording head, high-speed, high-definition recording and large-screen recording can be performed.

In such an ink jet recording apparatus, the viscosity of the ink is increased due to the evaporation or temperature decrease of the recording ink in the ink discharge port of the recording head, bubbles enter the nozzles of the recording head, the discharge port of the recording head. Discharge recovery means for preventing and recovering from clogging and ink discharge failure due to the attachment of foreign matter to the surface has been employed.

FIG. 11 shows an example of ejection recovery means in a conventional ink jet recording apparatus.
It is disclosed in, for example, JP-A-158467.

Hereinafter, description will be made with reference to the drawings. FIG.
The discharge recovery means shown in 1 is based on the suction recovery method,
An example of a recording head in which an ink cartridge 33 containing an ink absorber 34 containing the recording ink 12 is connected via a connector 9 is shown. The recording ink ejected from each nozzle 5 during the recording operation of the recording head 1 is connected to the ink supply path 41 and the connector from the ink absorber 34 of the ink cartridge 33 every time the recording ink in the common liquid chamber 8 is consumed by the recording operation. The recording operation of the recording head 1 can be stably continued by being supplied to the common liquid chamber 8 of the recording head 1 via the recording head 9. By the way, as described above, the recording ink in the nozzles of the recording head 1 increases in viscosity due to evaporation or low temperature, and the recording ink in the nozzles 5 and the common liquid chamber 8
If air bubbles enter the inside or foreign matter adheres to the ejection port surface 11 of the recording head 1, the recording head 1
And a stable and normal recording operation cannot be performed.
Therefore, the suction recovery method includes the ink absorber 34,
After the suction cap 42 connected to the suction pump 37 via the ink discharge tube 44 abuts on the outside area of the recording nozzle of the discharge port surface 11 of the recording head 1 via the cap sealing rubber 43 and is sealed, the suction pump is Drive 37,
With the air pressure Ps in the closed space between the suction cap 42 and the ejection port surface of the recording head set to a negative pressure lower than the atmospheric pressure, the recording ink is sucked and discharged from the nozzles of the recording head 1 and collected in the waste ink tank 35. Is performed for the recording head.

Such a discharge recovery means of the suction recovery method has been employed in many small-sized ink jet recording type printers because it has a simple structure and is convenient for cost reduction.

In recent years, there has been an increasing demand for high-speed recording, low cost, and downsizing of ink jet printers, and high-speed recording using a recording head having 256 or more nozzles is possible and low cost. Commercialization of a small-sized inkjet recording printer has been desired.

[0020]

However, when performing a discharge recovery operation by a suction recovery method with a multi-nozzle recording head having 256 or more recording nozzles, the recording nozzle width is long, so that all the recording nozzles must be used. It becomes difficult to achieve the same suction condition, and as shown in FIG. 12, as the number of recording nozzles increases, the total amount Q (cc) of waste ink discharged from each nozzle of the recording head during the suction recovery operation ) Increases, and the volume of the waste ink tank 35 for collecting waste ink must be increased,
The problem that running cost also increased had arisen.

Therefore, in the present invention, even if a long multi-nozzle print head having 256 to 5000 print nozzles is used for high-speed printing, downsizing and cost reduction can be achieved, and the cost is high. It is an object of the present invention to provide an ink jet recording apparatus capable of maintaining the ejection recovery performance.

[0022]

Another object of the present invention is to provide a cap having a plurality of internal spaces for covering a plurality of discharge ports for discharging ink, and communicating with the plurality of internal spaces of the cap, respectively. A plurality of communication passages, a pump commonly communicating with the plurality of communication passages, and a pump for causing a pressure change in the plurality of internal spaces when the cap covers the plurality of discharge ports; and And a plurality of valves that are respectively provided in the communication paths and that can be opened and closed independently of each other.

(Operation) According to the present invention, when the suction recovery means is employed for a long multi-nozzle recording head having a recording nozzle number of 256 nozzles to 5000 nozzles, the number of nozzles of the multi-nozzle of the recording head increases. , The volume of the waste ink tank 35 for collecting waste ink can be reduced.
It is possible to provide an ink jet recording apparatus capable of achieving a reduction in size, cost, and running cost of the ink jet recording apparatus, and also achieving high recovery performance for each nozzle of the recording head.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing the configuration of an embodiment of an ink jet recording apparatus according to the present invention. In FIG. 1, a recording head 1 and a recording medium (not shown) such as paper are shown. Platen roller 2 for forming and holding recording surface
3, a recording medium in the form of continuous paper or cut paper is fed to a platen roller 23 by a pinch roller (not shown).
It is conveyed while being pressed against. The recording head 1 is mounted on a carriage 21, and is serially driven in the directions S _A and S _{B in the} figure along two guide rails 24a and 24b. In the process, recording on a recording medium is performed. . The carriage 21 has a pulley 28a
Belt 29 and pulley 2 provided between
Through 8a, connected to the shaft 27 of the motor 26, S _A, driving the S _B direction is performed in accordance with the rotation of the motor 26.

The recording head 1 has, for example, four recording units corresponding to four colors of yellow (Y), magenta (M), cyan (C) and black (B).
Recording units for recording Y, M, C, and B include:
Independent ink supply paths are provided, and the ink tanks 19Y, 19M, 19C, and 19B are connected to the Yell via ink supply pipes 20Y, 20M, 20C, and 20B, respectively.
ow, Magenta, Cyan, and Black inks are supplied.

Capping means 22 and suction cap 42
Is provided outside the recording image area by the recording head, and the ejection recovery operation by the suction cap 42 is performed when the carriage 21 on which the recording head 1 is mounted moves to the home position HP, and then the suction cap 42 faces the recording head 1. This is performed after the suction cap 42 moves in the direction of arrow f and comes into contact with the ejection opening surface of the recording head 1.

Similarly, the capping operation by the capping means 22 is similar to the following. After the carriage 21 moves to the capping position CP, the capping means 22 moves in the direction of arrow f with the capping means 22 facing the recording head 1. This is performed by abutting the ejection port surface of the recording head 1.

Next, the ejection recovery operation of the suction recovery method in the ink jet recording apparatus of the present invention will be described with reference to the drawings.

FIG. 2 is a model diagram showing the suction recovery operation of the recording head 1 of the ink jet recording apparatus of the present invention.
Reference numeral 3 denotes a state in which the nozzle 3 is in contact with the area outside the recording nozzle on the ejection opening surface of the recording head 1 and is sealed.

Each of the nozzles 5 of the recording head 1
And a filter unit 46 having a filter for preventing intrusion of foreign matter into the common liquid chamber 8 of the recording head 1. The filter unit 46 is joined to the filter unit 46 and shared by the ink supply path 41. An ink supply unit 40 that supplies recording ink in connection with the liquid chamber 8 is provided.

That is, as described above, in the discharge recovery operation of the suction recovery method, the suction cap 42 connected to the suction pump 37 via the ink discharge tube 44 is connected to the discharge port of the recording head 1 via the sealing rubber 43 for the cap. After contacting and sealing the area outside the recording nozzle on the surface 11, the suction pump 37 is driven to reduce the pressure Ps in the closed space between the suction cap 42 and the ejection port surface of the recording head to one pressure below atmospheric pressure. With such a negative pressure state, the recording ink is sucked and discharged from the nozzles of the recording head 1 to perform the discharge recovery processing of the recording head. However, as shown in FIG. 13, the recording head 1 is connected to the common liquid chamber 8 of the recording head 1 for a multi-nozzle recording head 1 having a long number of recording nozzles such as 256 to 5000 nozzles. When the ink supply path 41 is arranged as shown in FIG. 13, when the negative pressure Ps by the suction cap 42 is uniformly applied to each nozzle of the print head, the ink is sucked and discharged from each nozzle of the print head 1. The flow of the recording ink 12 in the common liquid chamber 8 is caused by the difference between the liquid path resistance in the common liquid chamber 8 of the recording head and the connector between the common liquid chamber 8 and the ink supply path 41 as shown by the arrow 1 in the figure. The area closer to the part 9 is more likely to flow. As a result, initially, after the suction cap 42 abuts on the discharge port surface of the recording head 1 and is sealed, the suction pump 37 is driven to move the inside of the closed space between the suction cap 42 and the discharge port surface of the recording head. Immediately after the suction pressure is applied uniformly to each nozzle of the print head 1 and the recording ink is started to be sucked and discharged from all the nozzles of the print head, the common liquid is set to a uniform negative pressure Ps state equal to or lower than the atmospheric pressure. The recording ink is more likely to be sucked and discharged from the recording nozzle in a region near the connector section 9 with the ink supply path 41 where the recording ink in the chamber 8 flows easily. As a result, as shown in FIG.
The ink amount qi sucked and discharged from each nozzle 5 of the recording head 1 by the suction recovery operation is the ink amount qmax discharged from the recording nozzle in a region close to the connector portion 9 and discharged from the recording nozzle in a region far from the connector portion 9. Ink amount qmin (qmax> qmin)
Depending on the location of the recording nozzle, a large or small difference occurs in the amount of ink discharged from the nozzle during the suction recovery operation.

[0033]

[Outside 1] Is more than necessary.

Therefore, in the present invention, as shown in FIG. 2, the suction area of the suction cap 42 as suction recovery means is divided into a plurality of areas corresponding to the nozzle area of the recording head. Suction area and suction pump 3
7, ink suction tubes 49a, 49b, 49c, 49d, 49e, 49f, 4
Opening and closing valves 51a, 51b, 51c, 51d, 51e, 51f as suction operation switching means in the middle of 9g.
51g is provided, and for each of the suction areas divided into the plurality of areas, the suction recovery operation is performed only for the recording nozzle area where the suction recovery operation needs to be performed by controlling the presence or absence of the suction operation of the print head. The total nozzle discharge ink amount Q during the suction recovery operation of the recording head 1 is reduced.

That is, when the ink supply path 41 connected to the common liquid chamber 8 for the multi-nozzle recording head 1 is arranged as shown in FIG. 2, the conventional suction recovery means as shown in FIG. As described above, when the suction recovery operation is performed, the recording ink flows more easily in an area closer to the connector section 9 with the ink supply path 41 of the common liquid chamber 8, and the amount of ink discharged from the nozzle during the suction recovery operation is reduced. In the present invention, since the recording nozzle area in the area close to the connector section 9 becomes excessive, and as a result, the total amount of ink discharged from the nozzle during the suction recovery operation increases, the partition wall 48a, 48b, 48c, 48d, 48e, 48f
And, as shown in FIG.
3, partition portions 50a, 50b, 50c, 50d, 50
e, 50f are provided, and when the suction cap 42 comes into contact with the area outside the recording nozzle on the discharge port surface 11 of the recording head 1,
The recording nozzle area of the recording head 1 is divided into a plurality of areas a, b,
It is configured to be divided into c, d, e, f, and g. Of the plurality of recording nozzle areas a, b, c, d, e, f, and g,
The suction recovery operation is performed only in the recording nozzle area where the suction recovery operation needs to be performed, so that the total nozzle discharge ink amount Q during the suction recovery operation can be reduced.

At the time of the suction recovery operation, the ink sucked and discharged from each recording nozzle 5 of the recording head 1 is supplied to the ink absorbers 34a, 34b, 34c, 34d, 34e,
After being absorbed once in 34f and 34g, the suction cap 42
52a, 52b, 52c, 52d, 52e, 5
2f, 52g to ink absorption tubes 49a, 49
b, 49c, 49d, 49e, 49f, and 49g, and are sucked into the valves 51a, 51b, 51c, 51d, 51
e, 51f, and 51g, and is discharged to the ink discharge tube 44, and finally recovered to a waste ink tank (not shown).

FIG. 4 is an explanatory diagram for explaining the suction recovery operation of the ink jet recording apparatus according to the present invention. An example of a method for controlling the presence or absence of the suction operation of the recording head 1 in the suction area divided into a plurality of areas will be described. Is shown.

That is, non-discharge detection means 53 for detecting the discharge state of each nozzle of the print head is provided at a position outside the recording area of the ink jet recording apparatus shown in FIG. The non-discharge generating nozzle area of the head 1 is detected, the suction recovery area for the recording head 1 is determined based on the detection signal, and the suction recovery operation is controlled only for the non-discharge generating nozzle area. I have.

The non-ejection detecting means 53 of this embodiment shows an example in which the ejection state of the recording head 1 is optically detected.
When an ejection state confirmation instruction signal of the recording head 1 is issued from a control unit (not shown), the carriage 21 on which the recording head 1 is mounted is moved and conveyed to a non-ejection detection position outside the recording area. To perform an ink droplet ejection operation (non-ejection detection ejection operation) for detecting the ejection state. At this time, the non-discharge detecting means 53 is arranged so that the ink droplet 56 discharged from each nozzle of the recording head 1 passes over the non-discharge detecting means 53, and which nozzle of the recording head 1 is in the non-discharge state. Or to detect. The non-ejection detecting means 53 is constituted by a light source such as a fluorescent lamp (not shown) in which the CCD sensor array 54 is illustrated, and the ink droplet 56 ejected from the recording head passes over a light receiving portion 55 between the light source and the CCD sensor array 54. Then, an output signal is output from the CCD sensor array 54 according to whether the ink droplet 56 has passed over the light receiving portion 55 or not, and as a result, non-discharge occurs in any nozzle area of the recording head. Is determined.

That is, as shown in FIG. 4, the temporal ejection timing for the recording nozzles in the nozzle areas corresponding to the suction areas a, b, c, d, e, f, and g with respect to the recording head 1 The recording head is caused to perform the ejection operation of the ink droplet 56 while shifting t to to, ta, tb, tc... tg (sec), and it is determined whether the nozzle of the recording head is in the non-ejection state or the normal ejection state for each suction area. The discharge is detected by the discharge detecting means 53. For example, if a non-ejection nozzle is generated in the recording nozzle in the suction area c of the recording head, the ink droplet 56 ejected from the non-ejection generating nozzle does not pass over the light receiving section 55 of the non-ejection detecting means 53. The CCD sensor output corresponding to this nozzle area c is added to C corresponding to another nozzle area.
A region where the output is higher than the CD sensor output (a large amount of transmitted light from the light source when the discharged ink droplet passes through the light receiving unit 55) is detected, and as a result, a non-discharge generating nozzle is present in the nozzle region c of the print head. Is determined. Thereafter, the suction recovery operation is performed on the recording nozzle area c determined in this manner. That is, when the non-ejection detecting means 53 determines that the recording nozzles in the nozzle area c of the recording head 1 include the non-ejection recording nozzle, the valve 51c corresponding to the suction area c as shown in the table of FIG. Only the suction is released, and the suction recovery operation by the suction pump 37 is performed only on the suction area c.

The number of recording nozzles of the recording head is 256.
When driving a large number of recording heads such as nozzles at a high driving frequency of 4 kHz or more, driving all the recording nozzles of the recording head simultaneously requires a large-capacity power supply in terms of power supply capacity. In many cases, the driving method is performed in a time-division manner.

For this reason, in this embodiment, when the suction area of the recording nozzle is divided into a plurality of parts, each of the plurality of nozzles N driven at the same timing among the time-division driving of the two recording heads 1 has a different number. Suction areas a, b, c, d, e, f,
g, number of recording nozzles corresponding to g, Nb, Nc, Nd, N
e, Nf, Hg Na = nbN, Nb = nbN, Nc = ncN, Nd = n
By setting dN, Ne = neN, Nf = nfN, and Ng = ngN (na, nb, nc, nd, ne, nf, ng: a positive integer), the ink from the recording nozzles in each nozzle area is set. By ejecting the droplet, the non-ejection detecting means 5
According to 3, when detecting the ejection state of each nozzle of the recording head, the time lag when the ejected ink droplet 56 passes over the light receiving section 55 of the non-ejection detecting means 53 is reduced.
It is possible to improve the detection accuracy of the ejection state by the ink droplets 56 ejected from each nozzle.

FIG. 5 is a flow chart for explaining the suction recovery operation of the ink jet recording apparatus of this embodiment. When the control section (not shown) issues a discharge state confirmation instruction signal of the recording head 1 in step S1, recording is performed. The carriage 21 on which the head 1 is mounted is moved and conveyed to a non-discharge inspection position outside the recording area, and an ink droplet discharge operation (non-discharge detection idle discharge) for detecting a discharge state for each nozzle of the print head is performed. . Then, in step S2, a light receiving signal of the CCD sensor array 54 as the non-ejection detecting means 53 is detected. In step S3, it is determined whether or not there is a nozzle in which a non-ejection has occurred in the nozzle area of the recording head. Then, it is determined whether or not to perform the suction recovery operation. If it is determined that the suction recovery operation is not to be performed, a standby state is set in step S14.

On the other hand, if it is determined in step S3 that the suction recovery operation is to be performed, it is determined in step S4 which nozzle area of the print head is to be subjected to the suction recovery operation, and in step S5 the print head is determined. The suction recovery operation to 1 is started.

Then, as shown in FIG. 4, when the ejection failure occurs in the recording nozzle of the suction area c of the recording head, the valve 51c of the suction area c is opened in step S6, and the recording is performed in step S7. Carriage 2 with head
After 1 is moved and conveyed to the position of the suction cap and the suction cap 42 contacts the recording head, the suction pump 37 is driven in step S8, and the suction recovery operation is performed on the recording nozzles in the suction area c.

In step S9, the operation time t of the suction pump 37 is set to a predetermined operation time t set in advance.
p, and when the operation time of the suction pump 37 reaches tp, at step S10, the suction cap 4
2 is separated from the recording head, and the operation of the suction pump 37 is stopped in step S11. Then, step S12
, The valve 51c of the suction area c is closed, and step S1 is performed.
The suction recovery operation is completed in 3 and enters a standby state in step S14.

Here, the discharge state confirmation instruction signal may be output from the control unit at a predetermined timing, for example, when the power of the printing apparatus is turned on, at a predetermined number of prints, or at a predetermined time by a timer. As described above, the work clothes may be sequentially outputted, and the work clothes may be operated by a manual switch from an operation unit (not shown).

FIG. 6 is an explanatory diagram for explaining a second embodiment of the suction recovery operation of the ink jet recording apparatus according to the present invention. In this embodiment, a light receiving signal of the CCD sensor array 54 as the non-ejection detecting means 53 is used. When determining the suction area of the recording head, the suction recovery operation is performed on a nozzle area wider than the non-ejection-occurring nozzle area detected from the light receiving signal of the CCD sensor array 54.

That is, an ink droplet ejection operation for detecting the ejection state is performed for each nozzle of the recording head, and the light receiving signal of the CCD sensor array 54 as the non-ejection detecting means 53 is used as shown in FIG. Even when it is detected that non-ejection has occurred in the nozzle area c of the recording head, if the bubble 47 has entered the common liquid chamber 8 of the recording head 1, the recording nozzle in the nozzle area c Even when the suction recovery operation is performed, bubbles in the common liquid chamber 8 may not be sufficiently removed by suction. Therefore, in the present embodiment, when the non-ejection state of the recording nozzles in the nozzle area c is detected and the suction recovery operation of the recording head is performed, as shown in the table of FIG. The valves 51b and 51d of the adjacent nozzle areas b and d of the nozzle c are also opened so that the suction recovery operation is performed on the recording nozzles of the nozzle areas b and d in addition to the nozzle area c. Even when the nozzle 47 enters, the common liquid chamber 8 can be recovered by performing suction recovery on a wide area of the nozzle area.
Air bubbles 47 can be reliably removed from the inside by suction.

FIG. 7 is an explanatory view for explaining a third embodiment of the suction recovery operation of the ink jet recording apparatus of the present invention.
In the present embodiment, the operation conditions of the suction pump 37 are controlled when performing the suction recovery operation on a plurality of nozzle areas of the print head.

That is, CC as the non-ejection detecting means 53
It is detected from the light receiving signal of the D sensor array 54 that there are non-ejection nozzles in the plurality of nozzle areas c and e of the recording head, and as shown in the table of FIG.
1c and 51e are opened to perform a suction recovery operation on the recording nozzles in the nozzle areas c and e.

However, as described above, the plurality of suction areas c, e
When the suction recovery operation is performed on the, as shown in FIG.
Suction applied to the recording nozzle after a predetermined operating time t ₀ t ₀ = t _E −t _S (t _S : suction pump operation start time, t _E : suction pump operation stop time) of the predetermined suction pump 37. The pressure Ps becomes as shown by a broken line in the figure. For example, the suction pressure is lower than the suction pressure applied to the recording nozzle when the valve 51c is opened and the suction recovery operation is performed only on the suction area c. As a result, the suction recovery performance for each nozzle in the nozzle areas c and e of the recording head is reduced.

Therefore, in the present embodiment, as shown in FIG. 9, the operating conditions of the suction pump 37 are controlled in accordance with the number of nozzle areas in the nozzle area of the recording head for which the suction recovery operation is to be performed. As the nozzle area for performing the operation increases, the negative pressure Pp of the suction pump suction by the suction pump 37 increases.
Even if the number of suction nozzles during the suction recovery operation increases, the suction pressure of each nozzle of the print head is prevented from lowering, and the suction recovery operation is performed while maintaining sufficient suction recovery performance for each nozzle. I have to.

That is, as shown in FIG. 9, the nozzle area for performing the suction recovery operation of the recording head increases to 1, 2, 3,... And the number of open valves during the suction recovery operation increases to 1, 2, 3,. The suction pump suction negative pressure Pp is controlled to P ₁ by controlling the number of rotations and the operation time of the suction pump 37.
<P ₂ <P ₃ ... As the suction nozzle area increases, the suction negative pressure Pp by the suction pump is controlled to increase, thereby ensuring a sufficient suction pressure for each nozzle.

[0055]

As described above, according to the present invention,
The total amount of ink sucked and discharged from each nozzle of the multi-nozzle during the suction recovery operation of the recording head can be reduced, and the volume of a waste ink tank for collecting waste ink can be reduced.
It is possible to provide an ink jet recording apparatus that can achieve downsizing, low cost, low running cost, and high ejection recovery performance for each nozzle of the recording head.

In the present invention, the term "ink" refers to not only a normal ink containing a coloring material, but also a process used in recording for improving the fixability of a normal ink without a coloring material. It also contains liquid. Examples of the recording material on which recording is performed include not only general paper, but also cloth and three-dimensional parts, for example.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration of an embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a schematic side view of an ink jet recording apparatus using the present embodiment.

FIG. 3 is a top view showing the shape of the seal rubber of the suction cap of the present embodiment.

FIG. 4 is an explanatory diagram for explaining a suction recovery operation of the present embodiment.

FIG. 5 is a flowchart for explaining the suction recovery operation of the present embodiment.

FIG. 6 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 7 is an explanatory view showing a third embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between an operation time of a suction pump and a suction pressure.

FIG. 9 is a diagram showing a relationship between suction pressures in a third embodiment.

FIG. 10 is a schematic perspective view of an ink jet recording head according to a conventional technique.

FIG. 11 is a schematic side view of an ink jet recording apparatus according to a conventional technique.

FIG. 12 is a diagram for explaining a problem of a conventional ink jet recording apparatus.

FIG. 13 is a schematic side view for explaining suction recovery means of a conventional ink jet recording apparatus.

FIG. 14 is a diagram for explaining a problem of suction recovery means of a conventional ink jet recording apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Recording head 2 Substrate 3 Electrothermal transducer 4 Electrode 5 Nozzle 6 Top plate 8 Common liquid chamber 9 Connector 10 Liquid path 11 Discharge port surface 12 Ink 13 Discharge port 14 Recording ink drop 15 Mounting substrate 21 Carriage 22 Capping means 23 Platen roller 24a, 24b Guide rail 26 Motor 27 shaft 28a, 28b Pulley 29 Belt 19, 19B, 19G, 19M, 19Y Ink tank 20, 20, 20a, 20b, 20B, 20C, 20M, 20
Y Ink supply pipe 33 Ink cartridge 34 Ink absorber 35 Waste ink tank 37 Suction pipe 40 Ink supply unit 41 Ink supply path 42 Suction cap 43 Seal rubber for cap 44 Ink discharge tube 46 Filter unit 47 Bubbles 48 Partition wall 49 Suction tube Reference Signs List 50 partitioning section 51 valve 52 suction port 53 non-discharge detecting means 54 CCD sensor array 55 light receiving section 56 discharged ink droplet

Claims (6)

[Claims] 1. A cap having a plurality of internal spaces for covering a plurality of discharge ports for discharging ink, a plurality of communication passages respectively communicating with the plurality of internal spaces of the cap, and the plurality of communication passages A pump for causing a pressure change in the plurality of internal spaces when the cap covers the plurality of discharge ports; and a pump provided in each of the plurality of communication passages, independently of each other. An ink jet recording apparatus comprising: a plurality of valves that can be opened and closed. 2. The ink jet recording apparatus according to claim 1, wherein the plurality of internal spaces of the cap communicate with each other. 3. A method according to claim 1, further comprising detecting means for detecting an ejection state of the ink from the plurality of ejection ports, and controlling the opening and closing of each of the plurality of valves in accordance with a result of the detection by the detection means. Or the inkjet recording device according to 2. 4. A control is performed such that a valve to be opened among the plurality of valves and a valve adjacent to the valve are both opened.
3. The ink jet recording apparatus according to claim 1. 5. The ink jet recording apparatus according to claim 1, wherein operating conditions of the pump are changed according to the number of valves to be opened among the plurality of valves. 6. The ink jet recording apparatus according to claim 1, further comprising an electrothermal converter that generates heat energy used for discharging ink from the plurality of discharge ports.