JP4418187B2 - Inkjet recording device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an ink jet recording apparatus.
[0002]
[Prior art]
[Patent Document 1]
JP-A-11-105303 [Patent Document 2]
JP-A-7-246711 [Patent Document 3]
JP-A-11-320913 [Patent Document 4]
Japanese Patent Laid-Open No. 2000-15836
Recording devices having functions such as printers, facsimiles, copying machines, etc., recording devices used as output devices such as composite electronic devices including computers and word processors, and workstations, are based on image information (recording information). In addition, an image including characters and symbols is recorded on a recording material (recording medium) such as a plastic sheet or an OHP sheet.
[0004]
There are various types of such a recording apparatus, and among them, an ink jet recording apparatus (inkjet recording apparatus) performs recording by ejecting ink from a recording head to a recording medium. Can be recorded at high speed, can be recorded on plain paper without the need for special processing, running costs are low, and the non-impact method reduces noise. In addition, there is an advantage that it is easy to form a color image using various types of ink (for example, color ink).
[0005]
In such an ink jet recording apparatus, recording is performed by ejecting ink droplets from the ejection port of the head, so the state of the ejection port greatly affects the recording quality (image quality). Therefore, there is a maintenance / recovery method for refreshing (recovering) the discharge port by filling the recording head with ink by a pressurizing means or the like when a discharge failure (including non-discharge) occurs due to bubbles generated in the discharge port during recording. It is done. In addition, in order to prepare for thickening and fixing of the ink in the ejection port due to natural evaporation of the ink during standing for a long time or during transportation, the ejection port is covered (capped) with a highly-sealing cap member.
[0006]
By the way, in recent years, in response to a request for higher definition of recording, the density of discharge ports of the head has been rapidly increased, and a maintenance recovery mechanism that recovers the discharge ports as the density of discharge ports increases. There is a growing demand. In particular, in an inkjet recording apparatus using a so-called full line type long recording head (full line head) capable of recording at once over the width of the recording medium in the conveyance direction, the length of the maintenance recovery mechanism needs to be about the same as the recording head length. Therefore, the size becomes large and how to incorporate it into the recording apparatus is a problem.
[0007]
On the other hand, for example, [Patent Document 1] describes a pressure circulation method in which ink is filled in a recording head by a pressurizing means to recover an ejection port, and the ink used for the filling is recovered and reused. .
[0008]
This pressurizing and circulating method will be described with reference to FIG. The ink system in the pressure circulation method includes a recording head 101 that performs recording by discharging ink, an ink tank 102 such as an ink cartridge that stores a large amount of ink, an ink that temporarily stores ink, and an atmosphere. A sub-tank 103 having a communication port 108 and an electrode ink remaining amount detection sensor 109, a recovery rod 104 for receiving and recovering ink ejected from the recording head 101, and a first for supplying ink to the recording head 101 A pump 105, a second pump 106 such as a suction pump that supplies ink from the ink tank 102 to the sub tank 103 and collects ink from the recovery tank 104, a filter kit 107 that removes foreign matter contained in the ink, Consists of
[0009]
Then, ink stored in the ink tank 102 such as an ink cartridge is supplied and stored by the second pump 106 until a predetermined liquid level is reached in the sub tank 103, and ink can be supplied to the recording head 101. It becomes a state. At the time of printing, that is, at the time of recording, recording is performed by discharging ink from the recording head 101 onto a recording sheet such as paper, and the ink in the sub tank 103 is consumed.
[0010]
On the other hand, when the ejection of the recording head 101 is recovered, ink is circulated by the second pump 106 and the like, and the recovery processing of the recording head 101 is performed. At this time, the ink ejected from the nozzle 101a of the recording head 101 is received by the recovery rod 104, and foreign matter such as dust is removed from the recovery rod 104 together with air through the filter kit 107 by the suction of the second pump 106. After that, it is injected into the air layer 112 provided above the maximum liquid level of the sub tank 103. At this time, the ink falls downward due to gravity, and the air is discharged into the atmosphere from the atmosphere communication port 108 provided on the top surface of the sub tank 103.
[0011]
When ink in the sub tank 103 is consumed during recording and the electrode ink remaining amount detection sensor 109 detects a drop in the liquid level, the liquid level is returned to a predetermined liquid level. These operations are repeated, and the ink cartridge 102 is replaced when ink in the ink cartridge 102 runs out.
[0012]
[Patent Document 2] proposes a recovery rod arrangement method capable of compactly configuring the entire printer. This will be described with reference to FIG. At the time of non-recording and preliminary ejection, as shown in FIG. 5A, the ejection ports of the recording heads 122 to 122 held by the head holder 121 are sealed by a cap member 124 provided on the recovery rod 123, The thickening and sticking of the ink in the ejection port due to the natural evaporation of the ink when it is left is prevented. Further, by performing preliminary ejection from the ejection ports in this state, thickening and sticking due to natural evaporation of ink at ejection ports that are not ejected during recording is prevented.
[0013]
During recording, the recording head 122 is moved upward, and the recovery rod 123 having the cap member 124 and the blade member 125 is moved to the left in the drawing, as shown in FIG. The recording head 122 is moved close to the recording medium conveyed in the direction of the recording head to perform recording.
[0014]
By the way, in the method described above, a large amount of ink passes through the filter as the recording head becomes longer, and the recovery trap is exposed to the atmosphere during the recording operation. Impurities accumulate on the clogging. For this reason, the tube used for the ink pressurization circulation system may come off due to the pressure rise, and there is a possibility that troubles such as staining the inside of the apparatus with ink may occur.
[0015]
Therefore, [Patent Document 3] detects the clogging of the filter and stops the ink pressurization circulation based on the detection result, and [Patent Document 4] detects the clogging of the filter and Discloses a method for warning filter replacement.
[0016]
[Problems to be solved by the invention]
However, the above-described method is only a method for coping with clogging of the filter, and does not attempt to prevent clogging of the filter. In such a pressure circulation method and a recovery method using a recovery rod, it is necessary to have a configuration that prevents foreign substances from being mixed from the outside that cause filter clogging as much as possible. In addition, it is necessary to arrange a filter having an appropriate filtration accuracy at an appropriate place, and to incorporate the filter into the apparatus so that the filtration area of the filter is as large as possible.
[0017]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an ink jet recording apparatus that can prevent occurrence of a failure due to clogging of a filter and has excellent long-term reliability.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, an ink jet recording apparatus according to the present invention includes:
A recording head for ejecting ink;
An ink tank for storing ink;
A sub-tank for temporarily storing ink supplied from the ink tank;
Capping the recording head at the time of non-recording, and a recovery rod for receiving ink discharged at the time of recovery;
An ink supply path for supplying ink from the sub tank to the recording head ;
An ink return path for returning ink from the recording head to the sub tank;
And Lee ink recovery path for returning the ink in the recovery trough to said sub-tank,
First foreign matter filtering means for filtering foreign matter provided in the recovery bowl;
Second foreign matter filtering means for filtering foreign matter provided in the ink supply path ,
The filtration accuracy of the first foreign matter filtering means is lower than the filtration accuracy of the second foreign matter filtering means.
[0019]
Here, there is a third foreign matter filtering means for filtering the foreign matter provided in the ink recovery path ,
The filtration accuracy of the third foreign matter filtering means may be lower than the filtration accuracy of the first foreign matter filtering means and higher than the filtration accuracy of the second foreign matter filtering means.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. An ink jet recording apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 is a schematic configuration diagram of a head unit of the recording apparatus, and FIG. 2 is a configuration diagram of an ink pressurization circulation system of the recording apparatus.
[0021]
First, referring to FIG. 1, this ink jet recording apparatus is a full line type ink jet recording apparatus for ejecting ink droplets onto a recording medium (hereinafter referred to as “paper”) to form an image. Four recording heads 1 are held and arranged in the head holder 2 at equal intervals in the paper conveyance direction.
[0022]
The head holder 2 is moved up and down in the direction of the arrow in the figure based on a detection signal from a predetermined position sensor by a head holder lifting mechanism (not shown).
[0023]
Here, the four recording heads 1 are recording heads that discharge yellow, magenta, cyan, and black inks. Further, when a fixing accelerating liquid head is used in combination with each of these recording inks or when photo ink is used, the fixing accelerating liquid head or the photo ink recording head is attached to the head holder 2 in the same manner as the ink recording head. It can be set as the structure hold | maintained.
[0024]
Each recording head 1 is, for example, a thermal head, and has an ink discharge portion in which a plurality of ink discharge ports are formed across the entire recording surface so as to face the recording surface of the paper. The ink discharge ports are formed at predetermined intervals in the direction perpendicular to the paper surface of FIG. This interval is preferably an interval corresponding to a recording density of 600 dpi or more from the viewpoint of image quality. Each ink discharge port communicates with each ink flow path formed in the ink discharge portion, and the other end of each ink flow path joins the common ink chamber. Further, in each ink flow path, a heater as an electrothermal converter that heats ink and discharges it as droplets through an ink discharge port due to a film boiling phenomenon is formed via a protective layer.
[0025]
Each recording head 1 is not limited to a thermal type, and a head that deforms a diaphragm with an electromechanical transducer such as a piezoelectric element and ejects droplets, and a diaphragm that deforms with an electrostatic force and ejects droplets. Various heads such as a head can be used.
[0026]
A recovery rod 3 corresponding to each recording head 1 is disposed below the recording head 1, and the tip of the recovery rod 3 is selectively applied to the ink ejection port surface of each recording head 1. A plurality of cap members 4 in contact with each other, and a plurality of blade members 5 for selectively wiping ink, dust and the like adhering to the ink discharge port surface of each recording head 1 are provided.
[0027]
The recovery rod 3 is held by the recovery rod holder 6 and is movable with respect to the recovery rod holder 6 in the direction indicated by the arrow in FIG.
[0028]
The cap member 4 is provided at a position upstream of the blade member 5. The cap member 4 is integrally formed of an elastic material, and has a lip portion 4 a that forms an open end at a tip portion facing the ink discharge port surface of the recording head 1. The lip portion 4a is formed so as to surround the ink discharge port array on the ink discharge port surface when contacting the ink discharge port surface.
[0029]
The blade member 5 is formed in a thin plate shape by an elastic material, and the width dimension extending in the direction perpendicular to the paper surface in FIG. 1 is set so as to be in sliding contact with the entire ink discharge port surface of the recording head 1. The recovery rod holder 6 is formed with an opening 6a through which the recording head 1 can pass.
[0030]
A sealing member 8 is provided as a sealing means for sealing the cap member 4 of the recovery rod 3 integrally with the head holder 2 (or the recording head 1). The sealing member 8 moves together with the recording head 1 when the recording head 1 is moved up and down by the cap holder elevating mechanism, and is attached to the cap member 3 of the recovery rod 3 when the recording head 1 is lowered to the recording position. Abut and seal.
[0031]
Further, as shown in FIG. 2, the recovery member 3 has the cap member 4 inserted therein, and a reinforcing member 9 made of a resin material is inserted into the cap member 4. At the bottom of the reinforcing member 9, a filter 10 which is a foreign matter filtering means made of metal fiber or sintered metal is integrally provided on the reinforcing member 9 by ultrasonic welding or the like. For this reason, the cap member 4 can be detached from the recess of the recovery rod 3, and the reinforcing member 9 and the filter 10 can be detached from the cap member 4.
[0032]
As described above, the filter 10 is provided on the recovery rod 3 and the filter 10 is detachably attached to the recovery rod 3, so that the cap member 4 or the filter 10 can be mounted even when the filter 10 is clogged. The filter 10 can be easily removed and the filter 10 can be easily replaced and reused for cleaning.
[0033]
In addition, as disclosed in Japanese Patent Laid-Open No. 11-309871, it is preferable that the plate-like ink removing member 11 is disposed inside the cap member 4 at a position facing the ejection port with a predetermined interval. In the recovery operation described later, ink that has flowed out from the ejection port is guided onto the filter 10 by the ink removing member 11, and the ink filtered by the pump is collected and reused.
[0034]
Next, referring to FIG. 3, the ink circulation system includes a recording head 1 for performing recording by ejecting the ink described above, an ink tank 12 such as an ink cartridge for storing a large amount of ink, and an ink. , A sub tank 15 having an atmosphere communication port 13 and an electrode ink remaining amount detection sensor 14, a recovery tank 3 for receiving and recovering ink discharged from the recording head 1, and a sub tank 15, an ink supply path (ink circulation path) 16 for supplying ink to the recording head 1, a pump 17 for pumping ink through the ink supply path 16 , and a filter disposed between the pump 17 and the recording head 1. 18 and an ink return path (ink circulation path) 19 for returning ink from the recording head 1 to the sub tank 15. Is supplied to the recording head 1 has an ink circulation system for recycled back ink in the sub tank 15 from the recording head 1.
[0035]
Here, the filter 18 is a final filter for the purpose of determining the filtration accuracy of the ink supplied to the recording head 1. For this reason, the filtration accuracy of the filter 18 is, for example, 3 μm, which is the maximum filtration accuracy in the ink system. Further, since the filter 18 is arranged in the ink supply path 16, it is difficult to increase the filter area.
[0036]
In addition, an ink recovery path 20 for recovering the ink discharged to the recovery tank 3 to the sub tank 14, a pump 21 for pumping ink through the ink recovery path 20, and a valve disposed on the downstream side of the pump 21 22 and a filter 23 disposed on the downstream side of the valve 22, and has an ink recovery system for recovering ink from the recovery tank 3 to the sub tank 15.
[0037]
Here, the filter 23 is provided for the purpose of extending the life of the filter 18, and the filtration accuracy of the filter 23 is set to 10 μm, for example, lower than the filtration accuracy of the filter 18. Further, since the filter 23 is disposed in the circulation path 20 and the replenishment path 24, it is difficult to increase the filter area.
[0038]
The recovery bowl 3 is provided with the filter 10 as described above for the purpose of removing dust and paper dust. The filtration accuracy of the filter 10 is set to, for example, 50 μm, which is the lowest in the ink system. . Since the filter 10 is disposed in the recovery bowl 3, it is easy to increase the filter area.
[0039]
Furthermore, an ink replenishment path 24 for replenishing ink from the ink tank 12 to the sub tank 15, a pump 25 for pumping ink through the ink replenishment path 24, a valve 26 disposed on the downstream side of the pump 25, and ink replenishment An ink replenishing system that replenishes ink from the ink tank 12 to the sub tank 15.
[0040]
The operation of this embodiment configured as described above will be described with reference to FIG.
First, the case where the recording operation by each recording head 1 is performed will be described. In this case, in the recording operation from the non-recording state and the recovery operation state shown in FIG. 1, each recording head 1 is raised to the position shown in FIG. Thereafter, the recovery rod 3 is moved downstream in the paper transport direction as shown in FIG.
[0041]
Then, as shown in FIG. 6C, the recording head 1 is lowered by the head holder lifting mechanism through the opening 6a of the recovery rod holder 6 to a position separated by a predetermined distance from the sheet conveying surface, and then the sheet Each of the recording heads 1 is driven while an image is conveyed to record an image on a sheet.
[0042]
During this recording operation, the sealing member 8 has substantially the same length as the recording head 1 and moves downward with the recording head 1, so that it comes into contact with the lip 4 a of the cap member 4 of the recovery rod 3. Thus, the recovery rod 3 is sealed from the atmosphere.
[0043]
In the configuration in which the recovery basket 3 is exposed to the atmosphere during recording as before, it is necessary to wait until the ink in the recovery basket 3 is completely recovered in order to shift from the standby state to the recording state. In contrast, in this ink jet recording apparatus, since the recovery rod 3 is sealed even during recording, it is possible to shorten the transition time from the standby state to the recording state, and at the same time, recover dust and paper dust during recording. Mixing into the bowl 3 can be prevented. Further, in order to perform wiping by the blade member 5, the head holder 2 is moved upward to a position where the blade 5 is in sliding contact with the ejection port surface of the recording head 1, and the recovery rod holder 6 is moved in the right direction in FIG. What is necessary is just to move to the conveyance direction upstream direction).
[0044]
Next, in the ink system, after the ink tank 12 is inserted into the apparatus, the ink stored in the ink tank 12 is supplied and stored by the pump 25 until the sub tank 15 reaches a predetermined liquid level. The recording head 1 can be supplied with ink.
[0045]
At this time, the ink in the ink tank 12 is filtered by the filter 23. In this step, the foreign matter to be filtered is a foreign matter that is mixed when the ink tank 12 is attached / detached. Therefore, the filtration accuracy of the filter 23 does not need to be as high as about 10 μm.
[0046]
At the time of printing, that is, at the time of recording, ink is ejected from the recording head 1 onto a paper (recording medium) such as paper, and recording is performed, and the ink in the sub tank 15 is consumed. At this time, the ink in the sub tank 15 is filtered by the filter 18 and supplied to the recording head 1. In this step, the foreign matter to be filtered is a foreign matter present in the ink, which has an important influence on the ejection characteristics. Therefore, the filter 18 has a high filtering accuracy of about 3 μm. The ink in the sub tank 15 is filtered by the filter 23, and the ink to the recording head 1 is filtered by the filters 23 and 18.
On the other hand, when the ejection of the recording head 1 is recovered, ink is pressurized by the pump 17 and the recovery process of the recording head 1 is performed. At this time, the ink ejected from the recording head 1 is received by the recovery rod 3 and is recovered from the recovery rod 3 to the sub tank by the pump 21. The ink of the recovery tank 3 is filtered by the filter 10 and the filter 23 and collected in the sub tank 15.
[0048]
The foreign matter to be filtered in this step is dust or paper powder that is the main cause of clogging of the filter in the ink jet recording apparatus that collects and reuses the ink generated in the recovery process. For this reason, the filtration accuracy of the filter 10 is about 50 μm, and the life of the filter 23 can be extended by increasing the area.
[0049]
Further, at the time of recording, since the recovery rod 3 is sealed by the sealing member 8 as described above, the mixing of dust and paper powder is remarkably reduced. Thereby, the life of the filter 23 of the ink system can be extended, and higher reliability can be maintained.
[0050]
【The invention's effect】
As described above, according to the inkjet recording apparatus according to the present invention, the first foreign matter filter means for filtering foreign substances provided in the recovery trough, second filtering the foreign matters provided in the ink supply path Since the first foreign matter filtering means has a lower filtering accuracy than the second foreign matter filtering means, a recording apparatus having excellent long-term reliability can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram in the vicinity of a head portion illustrating an embodiment of an ink jet recording apparatus according to the present invention. FIG. 2 is an enlarged explanatory view of a recovery rod of the recording apparatus. Fig. 4 is a schematic configuration diagram for explaining the operation of the recording apparatus. Fig. 5 is an explanatory diagram of an ink pressurization circulation system of a conventional recording apparatus. Fig. 6 is a diagram of a head portion of a conventional recording apparatus. Schematic explanatory diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Head holder, 3 ... Recovery rod, 4 ... Cap member, 5 ... Blade member, 6 ... Recovery rod holder, 10 ... Filter.

Claims (2)

A recording head for ejecting ink;
An ink tank for storing ink;
A sub-tank for temporarily storing ink supplied from the ink tank;
Capping the recording head at the time of non-recording, and a recovery rod for receiving ink discharged at the time of recovery;
An ink supply path for supplying ink from the sub tank to the recording head ;
An ink return path for returning ink from the recording head to the sub tank;
And Lee ink recovery path for returning the ink in the recovery trough to said sub-tank,
First foreign matter filtering means for filtering foreign matter provided in the recovery bowl;
Second foreign matter filtering means for filtering foreign matter provided in the ink supply path ,
An ink jet recording apparatus, wherein the filtration accuracy of the first foreign matter filtering means is lower than the filtration accuracy of the second foreign matter filtering means. A third foreign matter filtering means for filtering foreign matter provided in the ink recovery path ;
2. The ink jet recording apparatus according to claim 1, wherein the filtration accuracy of the third foreign matter filtering means is lower than the filtration accuracy of the first foreign matter filtering means and higher than the filtration accuracy of the second foreign matter filtering means. .

Images