JP2010000709A - Inkjet recorder - Google Patents

Abstract

An object of the present invention is to reduce the viscosity of dry ink that causes nozzle clogging when the apparatus is not used for a long time in an insufficient cap state, and to restore it to a normal state by a normal recovery operation.
An ink head that discharges and prints water-based ink supplied from an ink supply source from a nozzle, and is detachably attached to the ink head to seal the nozzle when the apparatus is not used for a long period of time. In the ink jet recording apparatus 1 including the cap 3, the water in the water-based ink evaporates and the remaining components are hardened to give moisture to the dry ink that causes nozzle clogging, and thus the cap 3 has a different opening from the nozzle. A humidifying liquid supply means 11 for supplying the humidifying liquid from the humidifying liquid supply port 4a and a control means 20 for controlling the supply of the humidifying liquid by the humidifying liquid supplying means 11 are provided.
[Selection] Figure 4

Description

  The present invention relates to an ink jet recording apparatus using water-based ink, and more specifically, when water is not used for a long period of time and the cap on the nozzle is insufficient, water in the water-based ink evaporates and remains. An ink jet recording apparatus capable of recovering nozzle clogging caused by the solidification of the components by a normal recovery operation.

  An ink jet recording apparatus that discharges ink from the nozzles of the ink head and prints on a recording medium such as printing paper is used as an ink head when printing by this apparatus is not performed for a long period of time, that is, when the apparatus is not used for a long period of time. Cap means is provided for attaching the cap and sealing the nozzle. By capping the nozzle in this way, the nozzle is shielded from the outside air, and thickening of the ink remaining in the nozzle can be suppressed.

  If the cap state is correct, the above-described ink jet recording apparatus is restored to a normal state by a recovery operation (purge, flushing, etc.) of recovery means provided in advance in this type of apparatus even after being left for several months to several years. be able to.

Further, for example, the inkjet recording apparatus disclosed in Patent Document 1 below includes a cap unit that seals the nozzles of the ink head during the pause period of the apparatus, and caps ink droplets from the nozzles of the ink head when the apparatus is paused. Discharge (flushing) into the means. Accordingly, it is possible to suppress the drying of the ink by decreasing the ratio of the moisturizing component in the space in the cap unit and at the same time increasing the ratio of the moisture. If such a flushing process is performed, nozzle clogging can be easily eliminated even when the apparatus is not used for a long period of time.
JP 2001-261112 A

  However, when the ink jet recording apparatus stops unexpectedly or when it is difficult to reliably cap all the ink heads as in the line head type ink jet recording apparatus having a large number of ink heads, the state is not in the capped state. Or it may be left for a long time in an insufficient cap state. As described above, when the ink jet recording apparatus is not used for a long period of time, the ink in the nozzles is extremely thickened when the cap state is not correct. In particular, when water-based ink is used as printing ink, the water component of the water-based ink evaporates and the remaining ink component (water-soluble solvent) dries and solidifies in the nozzle, resulting in nozzle clogging.

  Conventionally, nozzle clogging caused by such dry ink has been difficult to recover to a normal state by a normal recovery operation such as purge or flushing. Although the nozzle clogging is sometimes eliminated by performing the recovery operation many times, there is a problem that a long time is required and the amount of ink used for the recovery operation is increased. In the worst case, the ink head must be replaced, which increases the cost.

  Furthermore, even when the moisturizing liquid is flushed in the cap means when the apparatus is stopped as in the ink jet recording apparatus disclosed in the above-mentioned Patent Document 1, since the cap is in an insufficient cap state, the water content of the ink is removed from the gap or the like. It evaporates and is not very effective. In addition, the ink jet recording apparatus disclosed in Patent Document 1 prevents the occurrence of nozzle clogging due to the drying ink solidifying by suppressing the evaporation of ink in the nozzle when the apparatus is not used for a long period of time. It is not assumed that nozzle clogging has already occurred. For this reason, in this apparatus, when the ink in the nozzles is hardened and the nozzles are clogged, the ink (moisturizing liquid) cannot be ejected.

  Accordingly, the present invention has been made in view of the above circumstances, and reduces the viscosity of dry ink that causes nozzle clogging that occurs when the ink is not used for a long time in an insufficient cap state by utilizing the water absorption characteristics of the water-based ink. It is an object of the present invention to provide an ink jet recording apparatus that reliably eliminates nozzle clogging by a normal recovery operation, suppresses unnecessary ink consumption, and reduces unnecessary costs for ink head replacement.

Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments.
According to the first aspect of the present invention, the ink jet recording apparatus according to the first aspect of the invention seals the nozzle when the printing is not performed for a long period of time, and the ink head 2 that prints by ejecting the water-based ink supplied from the ink supply source from the nozzle. In order to achieve this, the ink jet recording apparatus 1 includes a cap 3 that is detachably attached to the ink head 2.
A humidifying liquid supply means 11 for supplying a humidifying liquid into the cap 3 from a different port (humidifying liquid supply port 4a) from the nozzle, and a control means 20 for controlling the supply of the humidifying liquid by the humidifying liquid supplying means 11. It is characterized by comprising.

  The ink jet recording apparatus according to claim 2 is characterized in that the control means 20 controls the supply of the humidifying liquid based on a signal from a detection means for detecting that the nozzle clogging has occurred.

  The ink jet recording apparatus according to claim 3 is characterized in that water-based ink from the ink supply source is used as the humidifying liquid supplied from the humidifying liquid supply means 11 into the cap 3.

  According to the ink jet recording apparatus of the first aspect of the present invention, when a nozzle clogging occurs due to dry ink when the ink jet recording apparatus using water-based ink as a printing ink has not been used for a long time, After the humidifying liquid supply means supplies the humidifying liquid into the cap, the apparatus is allowed to stand for a certain period of time, so that the dry ink that causes nozzle clogging absorbs the moisture of the humidifying liquid and lowers the viscosity. Thereafter, the normal clogging operation is performed to reliably eliminate nozzle clogging. As a result, it is possible to suppress ink consumption by performing a recovery operation such as purging many times, and it is possible to suppress wasteful cost because the ink head is not replaced.

  Further, since the humidifying liquid is supplied into the cap from a different port from the nozzle, the humidifying liquid can be supplied even if the nozzle is already clogged.

  Furthermore, according to the ink jet recording apparatus of the second aspect, the humidifying liquid is controlled to be supplied into the cap only when the detecting means detects nozzle clogging, so that unnecessary humidifying liquid can be dispensed with. Thus, the consumption of the humidifying liquid can be suppressed.

  Further, according to the ink jet recording apparatus of the third aspect, it is not necessary to separately prepare the humidifying liquid by using the water-based ink from the ink supply source as the humidifying liquid, and a tank for storing the humidifying liquid is unnecessary. Thus, the apparatus can be simplified.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a configuration diagram showing a humidifying liquid supply means provided in an embodiment of the ink jet recording apparatus of the present invention, FIG. 2 is a schematic plan view of a substrate of an ink head provided in the embodiment, and FIG. FIG. 4A to FIG. 4C are explanatory diagrams showing the procedure of the recovery operation.

  In this embodiment, water-based ink (hereinafter abbreviated as ink) supplied from an ink supply source (an ink tank or a replaceable ink cartridge) is ejected from a nozzle of an ink head and printed on a recording medium such as printing paper. Inkjet recording apparatus. A channel is connected between the ink supply source and the ink head by an ink channel. Note that a storage tank or the like for temporarily storing ink supplied from the ink supply source to the ink head may be provided at a position midway along the ink flow path. Further, the ink supply source, the ink head, and the like are provided with an air opening for opening the inside thereof to the atmosphere. Each of these air opening ports is controlled to open and close by a solenoid valve or the like.

  Reference numeral 2 in FIG. 1 denotes an ink head. The ink head 2 includes a number of nozzles (not shown) that eject ink onto a surface facing the printing paper. Examples of the ink head 2 include a thermal method in which bubbles are generated by heating and ink is ejected, and a piezo method using a piezo element that is deformed by a voltage. Any of these may be used in this embodiment. Good. Further, the ink head 2 has a line head system in which each color of black (K), cyan (C), magenta (M), and yellow (Y) is arranged along a direction orthogonal to the feeding direction of the printing paper. Alternatively, a serial head system that moves in a direction orthogonal to the feeding direction may be employed.

  As shown in FIG. 1, the ink jet recording apparatus 1 of this embodiment is provided with a cap 3. The cap 3 is detachably attached to the ink head 2 in order to seal the nozzles of the ink head 2 when printing by the apparatus 1 is not performed for a long period of time, that is, when the apparatus 1 is not used for a long period of time. The cap 3 is for preventing the ink remaining in the nozzle from drying when the apparatus 1 is not used for a long period of time. The cap 3 is formed of a bottomed cylindrical member whose outer shape is substantially the same as the outer shape of the nozzle formation surface 2 a of the ink head 2. Further, a humidifying liquid supply port 4a for supplying a humidifying liquid from a humidifying liquid tank 5 described later is provided on one side of the cap 3, and a humidifying liquid is supplied to a waste liquid tank 8 described later on the bottom of the cap 3. The humidification liquid discharge port 4b for discharging is provided.

  Although not shown, the cap 3 is provided with a wiping member formed in a strip shape by an elastic member such as rubber. The wiping member is for wiping and cleaning paper dust, dust, ink, and the like adhering to the nozzle in sliding contact with the nozzle formation surface 2a of the ink head 2.

  As shown in FIG. 1, the humidifying liquid tank 5 described above is a tank for storing the humidifying liquid, and is connected to the humidifying liquid supply port 4 a of the cap 3 via a flow path 6 (tube). A supply-side valve 7 for supplying and stopping the supply of the humidifying liquid by an opening / closing operation is provided in the middle of the flow path 6.

  The humidifying liquid supply means 11 is configured by the humidifying liquid tank 5, the flow path 6 and the supply side valve 7 including the cap 3.

  As shown in FIG. 1, the above-described waste liquid tank 8 is a tank for storing the humidifying liquid (waste liquid) discharged from the cap 3. The waste liquid tank 8 is connected to the humidifying liquid discharge port 4b of the cap 3 through a flow path 9 (tube). The waste liquid tank 8 is provided with an air release port (not shown) for opening the inside thereof to the atmosphere. In addition, a discharge side valve 10 is provided at an intermediate position of the flow path 9 to discharge and stop the humidification liquid in the cap 3 by an opening / closing operation.

  The humidifying liquid needs to be a liquid in which water is easily absorbed by the water-based ink used as printing ink in this embodiment. For this reason, water or a liquid having a small amount of moisturizing components is preferable. In addition, ink with much moisture may be used.

  As shown in FIG. 1, the ink jet recording apparatus 1 according to this embodiment includes a control unit 20 that controls the opening / closing operations of the supply side valve 7 and the discharge side valve 10. The control means 20 controls the supply of the humidifying liquid by opening and closing the supply side valve 7. Furthermore, the control means 20 also performs opening / closing control of the discharge side valve 10.

  The opening / closing control (humidification liquid supply control) of the supply side valve 7 by the control means 20 is performed based on a detection signal from a detection means (not shown) that detects nozzle clogging of the ink head 2.

  The detecting means provided in this embodiment detects that the nozzle 1 is clogged in the ink head 2 because the apparatus 1 has not been used for a long time in an insufficient cap state. There are various detection methods. Here, the principle of ink state detection disclosed in Japanese Patent Laid-Open No. 2001-322298 is used. The detection method will be briefly described below.

  As shown in FIG. 2, on a substrate 30 of the ink head 2 (see FIG. 1), a recording element (heater) 31 that applies heat to eject ink, and a drive element (driver) for driving the heater 31. ) 32, and a detection electrode 33 for detecting a voltage change between the heater 31 and the driver 32 generated in response to heat generated by the heater 31 via the ink on the substrate 30. Then, the detection electrode 33 on the substrate 30 detects a change in the voltage transmitted from the voltage generation region through the ink in an AC manner, and each detection voltage is changed according to the amount of ink present. The ink state for each nozzle (including the presence or absence of ink) can be detected.

  By detecting the ink state in the nozzle in this way, it can be detected that the inkjet recording apparatus 1 has not been used for a long time in an insufficient cap state.

From here, the procedure of the nozzle clogging recovery operation will be described with reference to FIGS.
First, when the inkjet recording apparatus 1 has not been used for a long time in an insufficient cap state (ST1 in FIG. 3), when this apparatus 1 is used, it is detected that nozzle clogging has occurred from the detection means. When the signal is transmitted to the control means 20, the control means 20 performs control to open the supply side valve 7 (ST2 in FIG. 3). Thereby, as shown in FIG. 4A, the humidifying liquid is supplied from the humidifying liquid tank 5 into the cap 3. At this time, the control means 20 performs control to close the supply side valve 7 at a timing such that the humidifying liquid becomes about half of the volume in the cap 3.

  Next, as shown in FIG. 4 (b), the cap 3 is attached to the nozzle forming surface 2a of the ink head 2 to form a cap state, and the apparatus 1 is left for a predetermined time (about 1 to 5 hours) (FIG. 3). ST3). By leaving it in the cap state in this way, the dried ink in the nozzle absorbs the water volatilized from the humidifying liquid and lowers the viscosity.

  After a predetermined time has elapsed, the control means 20 performs control to open the discharge side valve 9 (see FIG. 1), whereby the humidified liquid in the cap 3 is discharged to the waste liquid tank 8. At this time, even if the waste liquid tank 8 is opened to the atmosphere, the humidified liquid becomes a waste liquid due to a water head difference (a difference between the liquid level height of the humidified liquid in the cap 3 and the liquid level height in the waste liquid tank 8). It is discharged into the tank.

  Then, by performing a recovery operation (purge or the like) of the normal recovery means provided in the apparatus 1 (ST4 in FIG. 3), as shown in FIG. 4C, nozzle clogging is eliminated in the ink head 2. Can be restored to normal.

  According to the embodiment described above, when nozzle clogging occurs due to dry ink when the inkjet recording apparatus 1 using water-based ink as printing ink has not been used for a long period of time, the cap 3 is humidified in the cap state. After supplying the liquid, if the apparatus 1 is left as it is for a certain period of time, the dry ink which is the cause of nozzle clogging absorbs the moisture of the humidifying liquid and lowers the viscosity. Thereafter, the nozzle clogging can be surely eliminated by performing a normal recovery operation such as purging. As a result, it is possible to suppress ink consumption caused by performing a recovery operation such as purging many times, and it is also possible to suppress wasteful cost because the ink head 2 is not replaced.

  Further, by controlling the control means 20 to supply the humidifying liquid into the cap 3 only when receiving the detection signal from the detecting means, it becomes unnecessary to supply unnecessary humidifying liquid. Consumption can be suppressed.

  Further, since the humidifying liquid is supplied into the cap 3 through a path (flow path 6) different from the water-based ink discharged from the nozzle from the humidifying liquid supply port 4a which is a different port from the nozzle, nozzle clogging occurs. Even supply becomes possible.

  In the above-described embodiment, a dedicated humidifying liquid (water or the like) is used, and the humidifying liquid tank 5 that stores the humidifying liquid is used. For example, the apparatus 1 uses aqueous ink for printing. You may comprise so that it may supply in the cap 3 from an ink supply source as a humidification liquid. Thereby, it is not necessary to provide the humidifying liquid or the humidifying liquid tank 5, and the apparatus 1 can be simplified. The water-based ink as the humidifying liquid is supplied into the cap 3 through a different path (flow path 6) from the ink ejected from the nozzle.

  In the above-described embodiment, a method of detecting the ink state in the nozzle is used to detect nozzle clogging, but other detection methods may be used. As an example, there is a method of detecting a time when the apparatus 1 is not used by detecting a difference between a time when ink is not discharged from the ink head 2 and a time when ink is discharged next. In the case of this detection method, if the cap state is insufficient, it is detected that the nozzle 1 is clogged in most cases, and the device 1 is not used and the cap state is insufficient. When this happens, the above-described recovery operation must be performed.

It is a block diagram which shows the humidification liquid supply means with which one Embodiment of the inkjet recording device by this invention is provided. 2 is a schematic plan view of a substrate of an ink head provided in the embodiment. FIG. It is a flowchart which shows the procedure of the recovery operation | movement of nozzle clogging by the embodiment. (A)-(c) It is explanatory drawing which shows the procedure of the recovery operation | movement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inkjet recording apparatus 2 ... Ink head 3 ... Cap 11 ... Humidification liquid supply means 20 ... Control means

Claims (3)

An ink head that discharges and prints aqueous ink supplied from an ink supply source from a nozzle, and a cap that is detachably attached to the ink head to seal the nozzle when the printing is not performed for a long period of time. In an inkjet recording apparatus comprising:
An ink jet recording apparatus comprising: a humidifying liquid supply means for supplying a humidifying liquid into the cap from a different port from the nozzle; and a control means for performing supply control of the humidifying liquid by the humidifying liquid supply means. .   2. The ink jet recording apparatus according to claim 1, wherein the control unit performs supply control of the humidifying liquid based on a signal from a detection unit that detects that the nozzle is clogged.   3. The ink jet recording apparatus according to claim 1, wherein the humidifying liquid supply means uses water-based ink from the ink supply source as the humidifying liquid supplied into the cap.

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