JP2002086758A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording apparatus which can suppress wasting ink, and at the same time, can obtain a high cleaning effect. SOLUTION: Ink chambers 34, ink supply ports 35 and pressure generation chambers 36 are formed between a nozzle plate 31 and a diaphragm 32 in a recording head. An actuator 41 for opening/closing a channel is arranged adjacent to an actuator 40 for printing for discharging ink drops from a nozzle opening 15b. Ink supply ports 35 are selectively shut by the action of the actuator 41. Even if a failure state in discharging ink drops from the nozzle opening is detected by, e.g. an optical means, ink channels other than one corresponding to the nozzle in the discharge failure state are shut, and a negative pressure is applied by a capping means. Accordingly, the negative pressure can be efficiently applied to the nozzle in the ink discharge failure state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus having an ink jet recording head mounted on a carriage reciprocally driven in the width direction of a recording sheet and ejecting ink droplets from nozzle openings, and more particularly to the recording head. The present invention relates to an ink jet recording apparatus capable of suppressing waste of ink when performing a cleaning operation for restoring the ink discharge function of the present invention.

[0002]

2. Description of the Related Art A recording head mounted on an ink jet type recording apparatus, for example, ejects ink pressurized in a pressure generating chamber as ink droplets from a nozzle opening as ink droplets onto a recording sheet to perform printing. There is a problem that printing failure occurs due to an increase in the viscosity of the ink due to evaporation of the solvent, solidification of the ink, and mixing of air bubbles. For this purpose, the ink jet recording apparatus is provided with a capping means for sealing the nozzle forming surface of the recording head when the operating power is not supplied or during non-printing.

[0003] The capping means not only functions as a lid for preventing the drying of the ink in the nozzle openings when printing is stopped, but also seals the nozzle forming surface when the nozzle openings are clogged. In order to achieve a cleaning function that eliminates clogging due to solidification of the ink in the nozzle opening and ink ejection failure due to air bubbles entering the ink flow path by stopping and sucking and discharging ink from the nozzle opening by negative pressure from the suction pump. Has also been made.

[0004]

By the way, the cleaning operation performed in the conventional recording apparatus involves sealing the nozzle forming surface by the capping means as described above,
By applying a negative pressure from a suction pump, an operation of sucking and discharging ink from each nozzle opening is performed. Therefore, during the cleaning operation, the ink is uniformly discharged from all the nozzle openings.

[0005] Therefore, since a considerable amount of ink is discharged each time the cleaning operation is performed, there is a problem that the life of the ink cartridge is short and the burden of running cost is large. Further, since a negative pressure is applied to all the nozzle openings by one capping means from all the nozzle openings on the nozzle forming surface of the recording head, the negative pressure at the time of suction is dispersed, and the ink The suction flow rate of the ink from the defective nozzle in a state in which the ink is thickened or solidified is extremely reduced.

In recent years, the number of nozzles in a recording head has been increased, so that the above-mentioned phenomenon becomes more and more remarkable. Accordingly, it is necessary to improve the capacity of a suction pump. However, when the suction capacity of the pump is improved, not only does the pump increase in size, but also it is necessary to prepare a large drive motor for driving the pump. It is extremely difficult to fulfill the above demands in this type of recording apparatus that is trying to reduce the weight.

An object of the present invention is to solve the above-mentioned technical problems, and reduce the running cost by extending the life of an ink cartridge.
It is an object of the present invention to provide an ink jet recording apparatus that can be made smaller and lighter.

[0008]

An ink jet recording apparatus according to the present invention, which has been made to solve the above-mentioned problems, is mounted on a carriage reciprocally driven in the width direction of a recording sheet, and is provided with an ink cartridge. An ink jet recording head that receives ink supply and ejects ink droplets from nozzle openings, and seals the recording head,
An ink-jet recording apparatus comprising: a capping unit that sucks and discharges ink from a recording head by receiving a negative pressure from a negative pressure generating unit, wherein a part of an ink flow path from the ink cartridge to a nozzle opening of the recording head An ink flow path opening / closing means that can open and close the ink flow path, and a discharge state monitoring means that monitors a discharge state of ink droplets discharged from each nozzle opening in the recording head, When the ejection state monitoring means detects an ejection failure state of ink droplets from a nozzle opening in the recording head, the ink passage opening / closing means closes an ink flow path communicating with other than the nozzle opening, and the capping means The recording head is configured to be able to suck and discharge ink by applying a negative pressure.

In this case, the discharge state monitoring means preferably comprises a light emitting element and a light receiving element, and an optical axis extending from the light emitting element to the light receiving element is mounted on a carriage and moved to form a nozzle of the recording head. The optical axis is disposed so as to cross the vicinity of the surface, and the optical axis is inclined at a predetermined angle with respect to a straight line connecting the nozzle rows of the recording head. Then, a laser light emitting semiconductor element can be suitably used as the light emitting element, and a photodiode can be suitably used as the light receiving element.

On the other hand, the ink flow path opening / closing means is preferably arranged individually in an ink flow path reaching each nozzle opening of the recording head. In this case, the ink passage opening / closing means preferably includes a passage opening / closing actuator for displacing a part of a diaphragm driven by a printing actuator, and communicates with a pressure generating chamber formed by the diaphragm. The ink supply port is configured to be able to be closed by driving the flow path opening / closing actuator. In addition, preferably, the printing actuator and the flow path opening / closing actuator are each constituted by a piezoelectric element.

According to the ink jet recording apparatus constructed as described above, the ejection state monitoring means monitors the ejection state of ink droplets ejected from each nozzle opening in the recording head, and the ejection state monitoring means monitors the ejection state of the ink droplets. When the discharge failure state is detected, the ink flow path opening / closing means closes the ink flow path communicating with the nozzle opening other than the discharge failure state nozzle opening.

Then, by applying a negative pressure to the capping means in a state where the nozzle forming surface is sealed, a negative pressure is selectively applied to the nozzle in the ejection failure state.
Therefore, a negative pressure is efficiently applied to the nozzle in the ink discharge failure state, and the flow rate of the ink discharged from the nozzle can be increased. This makes it possible to instantaneously recover the state of defective ink ejection at the nozzle.

Therefore, the capacity of the suction pump and the drive motor need only be relatively small, which can contribute to the reduction in size and weight of the recording apparatus. Also,
Since the operation of sucking and discharging the ink is performed from the nozzle having the defective ink discharge, the waste of the ink due to the cleaning operation can be minimized, and the life of the ink cartridge can be extended.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to the present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a perspective view showing a typical configuration of a recording apparatus main body to which the present invention is applied. FIG.
Reference numeral 1 denotes a carriage, and the carriage 1
Is configured to be guided by a guide member 4 via a timing belt 3 driven by a carriage motor 2 and reciprocated in the axial direction of a platen 5. On the surface of the carriage 1 facing the recording paper 6, an ink jet recording head described later is mounted. Above the ink jet recording head, a black ink cartridge 7 for supplying ink to the recording head and a color ink cartridge 8 are provided. It is removably loaded.

In the drawing, reference numeral 9 denotes capping means arranged in a non-printing area (home position). The capping means 9 performs recording when a recording head mounted on the carriage 1 moves directly above. The nozzle forming surface of the head is configured to be sealed. Below the capping unit 9, a suction pump 10 as a negative pressure generating unit for applying a negative pressure to the internal space of the capping unit 9 is arranged.

The capping means 9 functions as a lid for preventing the nozzle openings of the recording head from drying during the idle period of the recording apparatus, and also applies a driving signal unrelated to printing to the recording head to apply ink droplets. Functioning as an ink receiver at the time of a flushing operation for causing the ink to be ejected idly, and by applying a negative pressure from the suction pump 10 to the recording head,
It also has a function as a cleaning means for sucking and discharging ink.

On the print area side adjacent to the capping means 9, a wiping member 11 made of an elastic material such as rubber can move in a horizontal direction with respect to the movement locus of the recording head mounted on the carriage 1. Are arranged as follows. Then, the carriage 1 is moved to the capping unit 9.
When reciprocating to the side, the wiping member 11 advances as necessary on the movement path of the recording head, and slides on the nozzle forming surface of the recording head to clean the nozzle forming surface. ing.

FIGS. 2 and 3 schematically show the structure of the discharge state monitoring means mounted on the printing apparatus shown in FIG. FIG. 2 is a top view showing an arrangement relationship of the discharge state monitoring means, and FIG. 3 shows a basic configuration of the monitoring means. This discharge state monitoring means 21 is arranged near the home position where the capping means 9 is arranged as shown in FIG. The recording head mounted on the carriage 1 has a function of optically monitoring the ejection state of ink droplets ejected from each nozzle opening in a recording head described later.

As shown in FIG. 3, the discharge state monitoring means 21
Is basically composed of a light emitting element 22 and a light receiving element 23. As the light emitting element 22, a laser light emitting semiconductor element is used, and as the light receiving element 23, a photodiode is used. The laser light emitted from the laser light emitting semiconductor element 22 as the light emitting element,
The light is condensed through the lens 24 and further
Is configured to be incident on the photodiode 22 as a light receiving element.

An optical axis 2 extending from the laser emitting semiconductor element 22 to the photodiode 22 as a light receiving element.
Numeral 6 is configured to traverse the vicinity of the nozzle forming surface of the recording head 15 that is mounted and moved on the carriage 1. It is configured to be focused.

FIG. 4 illustrates the operation of monitoring the ejection state of ink droplets ejected from each nozzle opening by the ejection state monitoring means 21 having the above-described configuration.
As shown in FIG. 4, the optical axis 26 emitted from the laser emitting semiconductor element 22 is configured to be inclined at a predetermined angle (θ) with respect to a straight line 15 a connecting the nozzle rows of the recording head 15. Have been. This angle (θ) is
The arrangement positions of the nozzle openings 15b do not overlap on the optical axis 26.
Is moved in the direction of the arrow, so that the optical axis 26 sequentially scans the respective nozzle openings 15b.

Therefore, for example, when the nozzle opening indicated by a black circle is in a state where ink droplets cannot be discharged, the optical axis 26 reaches the photodiode 22 without being blocked by the ink droplets. As a result, it is detected that the nozzle opening indicated by the black circle is in an ink droplet ejection failure state.

FIGS. 5 and 6 show the configuration of a recording head having an ink flow path opening / closing means capable of opening / closing an ink flow path using a detection output detected by the above-described discharge state monitoring means 21. FIG. It is a thing. The configuration shown in FIGS. 5 and 6 is a sectional view mainly showing the configuration of an ink flow path and a pressure generating chamber portion that reach one nozzle opening. FIG. 5 shows a state in which the ink passage opening / closing means is open, and FIG. 6 shows a state in which the ink passage opening / closing means is closed.

Reference numeral 31 denotes a nozzle plate in which the nozzle openings 15b are formed.
A flow path substrate 33 is sandwiched between the substrate and the vibration plate 32 to form a substrate unit. The flow path substrate 33 includes:
A space is formed between the nozzle plate 31 and the vibration plate 32 such that an ink chamber 34, an ink supply port 35, and a pressure generating chamber 36 are respectively formed. The board unit is attached to the end surface of the head case 37.

On the other hand, fixed substrates 38 and 39 are mounted in the internal space of the head case 37. The fixed substrates 38 and 39 further include a printing actuator 40 and a flow path opening / closing actuator 41 using piezoelectric elements. Installed. The printing actuator 4
The zero and flow path opening / closing actuator 41 uses, for example, PZT having a longitudinal vibration / lateral effect, and contracts when the piezoelectric element is charged, and expands when discharged.

As shown in FIGS. 5 and 6, the PZT constituting the printing actuator 40 is coupled to the upper surface of the diaphragm 32 constituting the pressure generating chamber 36.
The diaphragm 32 is configured to be driven vertically in the drawing. Therefore, the pressure is intermittently applied to the pressure generating chamber 36 by the driving of the printing actuator 40, whereby the nozzle opening 15 b formed in the nozzle plate 31 is formed.
It acts to discharge more ink droplets.

The PZT constituting the flow path opening / closing actuator 41 is a vibration plate 32 constituting the ink supply port 35.
, And is configured to drive the diaphragm 32 in the vertical direction in the figure. Accordingly, the state where the ink supply port 35 communicating with the pressure generating chamber 36 is opened as shown in FIG. 5 and the state where the ink supply port 35 is closed as shown in FIG. Act to be selected.

In the above arrangement, when the ejection state monitoring means 21 for monitoring the ejection state of the ink droplets detects a state of defective ejection of the ink droplets from the nozzle openings in the recording head, the carriage 1 is moved to the home position. Then, the nozzle forming surface of the recording head is sealed by the capping means 9 described above. Then, PZT constituting the actuator 41 constituting the ink flow path opening / closing means
Is to close an ink flow path corresponding to a portion other than the nozzle opening that has fallen into an ink droplet ejection failure state.

In this state, the suction pump 10 is driven. As a result, the ink is sucked and discharged from the nozzle opening which has received the negative pressure and is in an ink droplet ejection failure state. Accordingly, it is possible to efficiently apply a negative pressure to the nozzles in the ink ejection failure state, and it is possible to further increase the flow rate of the ink discharged from the nozzles. Therefore, it is possible to instantaneously recover the state of defective ink ejection in the nozzle.

In the above-described embodiment, the actuator 41 constituting the ink passage opening / closing means includes the ink supply ports 35 reaching the nozzle openings 15b of the recording head.
Although the actuators 41 are individually arranged, the actuator 41 constituting the ink passage opening / closing means only needs to be arranged in a part of the ink passage from the ink cartridge to the nozzle opening of the recording head. For example, a part of an ink flow path from an ink cartridge to a head chip of a recording head, or the above-described ink chamber 3 in the head chip.
4 may be arranged in a part of the ink flow path.

In this case, when the actuator constituting the ink passage opening / closing means operates, the ink passages of black, yellow, cyan, and magenta act to be opened or closed at a time. As shown in (1), an effect of opening or closing the ink supply port of each nozzle cannot be obtained. However, compared to the embodiment, the configuration can be much simplified, and the suction and discharge of ink during the cleaning operation can be much improved compared to the conventional configuration.

[0032]

As is apparent from the above description, according to the ink jet recording apparatus of the present invention, when the ejection state monitoring means detects the ejection failure state of the ink droplet from the nozzle opening, the nozzle in the ejection failure state is detected. Are blocked. Therefore, it is possible to efficiently apply a negative pressure to the nozzle in the ink ejection failure state by the capping unit,
In addition to suppressing waste of ink, a high cleaning effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a typical configuration of a recording apparatus main body to which the present invention is applied.

FIG. 2 is a top view showing an arrangement of a discharge state monitoring unit mounted on the printing apparatus shown in FIG. 1;

FIG. 3 is a schematic diagram showing a basic configuration of the monitoring means.

FIG. 4 is a schematic diagram illustrating a monitoring operation of a discharge state of ink droplets discharged from each nozzle opening performed by a discharge state monitoring unit.

FIG. 5 is a cross-sectional view illustrating a configuration of a recording head in which an ink flow path opening / closing unit is in an open state.

FIG. 6 is a cross-sectional view illustrating a configuration of a recording head in which an ink flow path opening / closing unit is in a closed state.

[Explanation of symbols]

 Reference Signs List 1 carriage 2 carriage motor 3 timing belt 4 guide member 5 platen 6 recording paper 7 black ink cartridge 8 color ink cartridge 9 capping means 10 suction pump 11 wiping member 15 recording head 15b nozzle opening 21 discharge state monitoring means 22 light emitting element 23 light receiving element 26 Optical axis 31 Nozzle plate 32 Vibration plate 34 Ink chamber 35 Ink supply port 36 Pressure generation chamber 40 Actuator for printing 41 Actuator for opening and closing flow path

Claims (6)

[Claims] 1. An ink jet recording head mounted on a carriage reciprocally driven in the width direction of a recording sheet, receiving ink supplied from an ink cartridge and discharging ink droplets from nozzle openings, and sealing the recording head. An ink jet recording apparatus comprising: a capping means for stopping the recording medium and sucking and discharging ink from the recording head by receiving a negative pressure from the negative pressure generating means, wherein the ink flow from the ink cartridge to a nozzle opening of the recording head is provided. An ink flow path opening / closing means which is arranged in a part of a path and can open and close the ink flow path; and an ejection state monitoring means for monitoring an ejection state of ink droplets ejected from each nozzle opening in the recording head. Is provided, and the discharge state monitoring means detects a state of defective discharge of ink droplets from nozzle openings in the recording head. When it is known, the ink flow path opening / closing means closes the ink flow path communicating with the other than the nozzle opening, and a negative pressure is applied to the capping means so that the ink can be sucked and discharged from the recording head. Ink jet recording device. 2. The discharge state monitoring means comprises a light emitting element and a light receiving element, and an optical axis from the light emitting element to the light receiving element is located near a nozzle forming surface of the recording head which is mounted on a carriage and moved. 2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is arranged so as to cross the recording head, and the optical axis is inclined at a predetermined angle with respect to a straight line connecting the nozzle rows of the recording head. 3. The light emitting device is a laser light emitting semiconductor device, and the light receiving device is a photodiode.
3. The ink jet recording apparatus according to claim 1. 4. The ink jet recording apparatus according to claim 1, wherein the ink flow path opening / closing means is individually arranged in an ink flow path reaching each nozzle opening of the recording head. 5. The ink flow path opening / closing means includes a flow path opening / closing actuator for displacing a part of a vibration plate driven by a printing actuator, and communicates with a pressure generating chamber formed by the vibration plate. 5. The ink jet recording apparatus according to claim 4, wherein the ink supply port can be closed by driving the flow path opening / closing actuator. 6. The ink jet recording apparatus according to claim 5, wherein the printing actuator and the flow path opening / closing actuator are each constituted by a piezoelectric element.