JP2719259B2 - Ink circulation device for inkjet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink circulating apparatus for an ink jet recording apparatus, and more particularly to an ink circulating apparatus suitable for a charge control type ink jet recording apparatus using an ink using a pigment.

[0002]

2. Description of the Related Art In a charge control type ink jet recording apparatus, the uniformity of ink particles formed by ink ejected from recording nozzles and the stability of charging characteristics greatly affect print quality. It is necessary to supply a uniform ink to the recording nozzle. However, since the pigment-based ink has a specific gravity of the pigment larger than that of the solvent and easily agglomerates among the pigments, the pigment is precipitated in the recording ink container holding the ink, and the recording is performed. The ink supplied to the nozzles lacks uniformity. In addition, the pigment that has grown greatly due to precipitation or aggregation causes clogging of filters, recording nozzles, and the like, and causes troubles such as failure of valves and pumps in the circulation path. In order to prevent such pigment precipitation or aggregation, for example, Japanese Patent Application Laid-Open
The apparatus described in JP-A-110458 uses a stirrer such as a magnetic stirrer.

[0003]

However, these conventional devices can prevent the precipitation and aggregation of the pigment in the ink holding container, but can prevent the pigment from being supplied to the ink in the replenishment flow path for replenishing the ink. Since no consideration is given to sedimentation or aggregation, there is a problem in that the pigment flows and flows only at the time of ink supply, and the ink in the ink supply flow path which is normally stationary causes the precipitation or aggregation of the pigment.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a uniform ink supply by eliminating precipitation and aggregation of the pigment in the ink in the ink supply flow path, thereby reducing troubles in the ink flow path. An object of the present invention is to provide an ink circulation device for a recording apparatus.

[0005]

SUMMARY OF THE INVENTION The present invention provides a recording ink holding container, an ink supply pipe for supplying ink held in the recording ink holding container to a recording nozzle, and ink ejected from the recording nozzle. An ink collection means for collecting and returning the ink not used for recording to the recording ink holding container, and being connected to the ink supply pipe from the supply ink holding container via an ink supply valve in the middle thereof In an ink jet recording apparatus having an ink supply pipe and an ink supply means for supplying ink to the ink supply pipe, the ink supply means returns the supply ink flowing through the ink supply pipe to the supply ink holding container. A supply ink circulation pipe and a supply ink circulation valve interposed in the supply ink circulation pipe are provided. The supply ink circulation pipe of the ink supply means is branched from the ink supply pipe, and the supply ink circulation pipe of the ink supply means is branched from the ink supply pipe. ,
A supply ink circulation pump is provided in the middle of the supply ink circulation pipe. Alternatively, a recording ink holding container, and an ink supply for supplying ink held in the recording ink holding container to a recording nozzle A tube, an ink supply valve and an ink supply pump interposed in the middle of the ink supply tube in the following order, and collecting and ejecting the ink ejected from the recording nozzles that have not been used for recording. An ink supply means for returning to the holding container, and an ink supply pipe connected downstream from the ink supply valve of the ink supply pipe via an ink supply valve on the way from the supply ink holding container. In an ink jet recording apparatus including an ink supply unit for supplying ink and a control device for controlling the ink supply unit, the ink supply unit supplies the ink supply unit with the ink supply unit. A supply ink circulation pipe for returning the supply ink flowing through the supply ink holding container to the supply ink holding container, and a supply ink circulation valve interposed in the middle of the supply ink circulation pipe, and specifically, The supply ink circulation pipe of the ink supply means is branched from the ink supply pipe, and the supply ink circulation pipe of the ink supply means is branched from the ink supply pipe; The means includes a supply ink circulation pump in the middle of the supply ink circulation pipe, and the control device opens the ink supply valve and the supply ink circulation valve in a state where the ink supply valve is closed, and starts the supply ink circulation pump. Driving is characterized.

[0006]

By circulating the supply ink in the ink supply tube to the supply ink holding container via the supply ink circulation tube, the progress of the precipitation and aggregation of the pigment in the ink supply tube is reduced. The agglomerated pigment is washed away by the supply ink and diffuses into the supply ink.

Accordingly, the occurrence of troubles in the ink flow path due to the precipitated and aggregated pigments is reduced.

[0008]

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

FIG. 1 is a block diagram of an ink circulation system of an ink jet recording apparatus according to the present invention. A filter 2 is provided in the recording ink holding container 1, and a recording ink supply pipe 3 is led out of the filter 2 and is provided with a recording ink supply control electromagnetic valve 4, a pressure pump 5, a pressure regulating valve 6, and a pressure gauge 7.
And the solenoid valve 8 and the check valve 9 are sequentially connected to the recording nozzle 10.

A filter 12 is provided in a replenishing ink holding container 11 for storing and holding replenishing ink, and an ink replenishing pipe 13 is led out of the filter 12 and supplied via a replenishing ink supply control electromagnetic valve 14. The recording ink supply pipe 3 is connected between the solenoid valve 4 and the pressure pump 5.

After the supply ink circulation pipe 15 branches off from the back of the solenoid valve 14 in the ink supply pipe 13, the supply ink circulation control electromagnetic valve 16 and the supply ink circulation pump 17 are sequentially interposed to supply ink. It is connected so as to return to the ink holding container 11.

At the bottom of the recording ink holding container 1 and the replenishing ink holding container 11, magnetic stirrers 18 and 20 for stirring ink are arranged.
The inks 9 and 21 are rotated to stir the ink.

A solvent supply pipe 23 led out of a solvent holding container 22 for holding and holding an ink solvent used for adjusting the physical properties of the ink includes a filter 24, a solvent supply pump 25, a solvent supply control solenoid valve 26, and a flow rate adjustment valve. It is connected between a gutter 28 and a filter 30 in an ink collection tube 29 described later via a diaphragm 27. In some cases, the throttle 27 may not be necessary due to the flow rate of the solvent supply pump 25 and the recovery pump 31. That is, when the recovery flow rate of the recovery pump 31 is set to be larger than the total flow rate of the ink amount ejected from the recording nozzle 10 and the solvent amount sent by the solvent supply pump 25, and the electromagnetic valve 26 is opened. However, if the ink captured by the gutter 28 can be sufficiently collected, the aperture 27 becomes unnecessary.

A gutter 28 for catching ink ejected from the recording nozzle 10 that has not been used for recording.
Is connected to the recording ink holding container 1 with the filter 30 and the recovery pump 31 interposed in this order.

The nozzle cleaning solvent supply pipe 32 is connected to the solvent supply pump 25 and the electromagnetic valve 26 in the solvent supply pipe 23.
And is connected to the check valve 9 via a cleaning control electromagnetic valve 33. In the ink circulation system in this embodiment, when the electromagnetic valve 33 is opened, a solvent is supplied to the recording nozzle
The control device 36 described later automatically opens the solenoid valve 33 when the ink is stopped to wash the recording nozzle 10 with the solvent.

The check valve 9 includes the recording ink supply pipe 3, the nozzle cleaning solvent supply pipe 32, and the recording nozzle 10.
In addition, a recording ink circulation pipe 34 is connected, and functions so that the recording ink in the recording ink supply pipe 3 and the recording ink circulation pipe 34 and the solvent in the nozzle cleaning solvent supply pipe 32 are not mixed. Have a check ball.

The recording ink circulation pipe 34 is connected to the recording ink holding container 1 via an electromagnetic valve 35,
By opening the electromagnetic valve 35, the recording ink immediately before the recording nozzle 10 can be circulated to the recording ink holding container 1 without passing through the recording nozzle 10. Can be quickly filled with the recording ink. Further, by periodically circulating the pigment, the pigment precipitated in the recording ink supply pipe 3 can be quickly diffused and removed.

The circulation of the recording ink, the replenishing ink, and the solvent is performed by controlling the solenoid valve and the pump by the control device 36.

Next, circulation control for preventing precipitation and aggregation of the pigment in the ink supply channel will be described with reference to FIGS.

FIG. 2 is a flowchart of a control process executed by the control device 36 for controlling ink circulation in the ink replenishment flow path while the supply of the recording ink is stopped to prevent precipitation and aggregation of the pigment.

In step 210, when the start signal of the control is confirmed by analyzing the key input of the operation panel or the signal from the outside of the device, the process proceeds to step 220 to execute the pump control, and the pump 17 is operated, and the pump 5 is operated. , 2
Put 5,31 into a dormant state. Here, pumps 5, 17, 2
If the pump 5 is of a type that shares its drive source, for example, a pump drive motor, and is equipped with protection such as a safety valve that does not increase the pressure above a certain value, all pumps can be kept in operation. Good.

Next, in step 230, the solenoid valves are controlled to open the solenoid valves 14, 16 and to keep the other solenoid valves 4, 8, 26, 33, 35 closed. Such control in steps 220 and 230 may be executed in one step. Since the ink in the ink supply pipe 13 and the ink in the recording ink circulation pipe 15 is forcibly circulated by the above control processing, the pigment precipitated or agglomerated in the flow path is swept away and diffused, and enters the supply ink holding container 11. Will be returned. The ink returned to the supply ink holding container 11 is stirred by the stirring rod 21 and diffused into the supply ink. Since only the ink that has passed through the filter 12 is sucked into the ink supply tube 13, the ink supply tube 13
The replenishment ink circulation pipe 15 is replenished with only normal and homogeneous replenishment ink that does not contain a large grown pigment.

Next, at step 240, the timer for controlling the supply ink circulation execution time is started, and at step 250, it is monitored that the timer reaches a set value. When the time-up is detected in step 250, the process proceeds to step 260, in which all pumps are stopped and all solenoid valves are closed to recirculate the replenishing ink for preventing pigment precipitation, aggregation and diffusion in the ink replenishment flow path. The control ends.

FIG. 3 is a flowchart of a control process executed by the control device 36 for ink replenishment and prevention of pigment precipitation and aggregation in the ink replenishment flow path.

Step 310 indicates that the recording ink in the recording ink holding container 1 is supplied to the recording nozzle 10 by the pump 5 and is being ejected (printed). When an instruction to supply ink is given from the operation panel or the like, step 32 is executed.
At 0, the ink supply control is executed. In this control, the electromagnetic valve 4 is closed and the electromagnetic valve 14 is opened to supply ink to the recording nozzles 10 from the supply ink holding container 11.

Next, the routine proceeds to step 330, where circulation control for preventing pigment precipitation and aggregation in the ink supply flow path is executed. In this control, the pump 17 is set to the operating state, and the solenoid valve 16 is set to the open state. Here, if the pumps 5, 17, and 25 are of a type that shares a drive source thereof, for example, a pump drive motor, and are provided with protection such as a safety valve that does not increase the pressure beyond a certain value, all of the pumps 5, 17, and 25 are performed in step 310. May be put into operation. The control in steps 320 and 330 may be executed in one step.

With the above control processing, it is possible to simultaneously execute the ink supply to the recording ink supply channel and the circulation of the supply ink in the ink supply channel. The replenishment ink supplied from the replenishment ink holding container 11 and ejected from the recording nozzle 10 but not used for recording is the gutter 28.
Is collected in the recording ink holding container 1 via the ink collecting pipe 29, and is supplied to the recording ink holding container 1 as recording ink.

In step 340, it is monitored whether or not the consumed amount of ink has been replenished. When the replenishment is completed, step 350 is executed to open the solenoid valve 4, to open the solenoid valves 14,16.
Is closed, the pump 17 is stopped, and the recording ink holding container 1 is closed.
Then, the process proceeds to step 360 in which the recording ink is supplied to the recording nozzle 10, and the ink replenishment, the pigment precipitation, and the aggregation prevention control processing are terminated.

Next, the deformation of the ink circulation system will be described. In the above embodiment, the supply ink circulation pipe 15
Is branched from the back path of the electromagnetic valve 14 in the ink supply pipe 13, but may be branched from the connection position of the ink supply pipe 13 in the recording ink supply pipe 3 and the pump 5.
Further, the pump 5 may be branched from the downstream side of the pump 5 in the recording ink supply pipe 3. In this case, the pump 5 can be used also for circulation of the replenishing ink, so that the pump 17 can be omitted.

[0030]

As described above, according to the present invention, the replenishment ink in the ink supply tube is circulated to the replenishment ink holding container via the replenishment ink circulation tube, whereby the pigment precipitates in the ink supply tube. In addition, since the progress of aggregation and aggregation are reduced, and the precipitated and aggregated pigments are washed away by the supply ink and diffused into the supply ink, the ink generated in the ink supply flow path which is stationary except at the time of supply is provided. Can eliminate the pigment precipitation and coagulation and supply a homogeneous ink, reduce the occurrence of troubles in the ink flow path, and stabilize the print quality.

[Brief description of the drawings]

FIG. 1 is a block diagram of an ink circulation system of an inkjet recording apparatus according to the present invention.

FIG. 2 is a flowchart of a control process executed by a control device for controlling ink circulation for preventing precipitation and aggregation of a pigment in an ink supply flow path while the supply of recording ink is stopped.

FIG. 3 is a flowchart of a control process executed by a control device for ink replenishment and prevention of pigment precipitation and aggregation in the ink replenishment flow path.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 recording ink holding container 3 recording ink supply tube 4 recording ink supply control solenoid valve 5 pressurizing pump 10 recording nozzle 11 supply ink holding container 13 ink supply tube 15 supply ink circulation tube 16 supply ink circulation control electromagnetic Valve 17 Supply ink circulation pump

Claims (8)

(57) [Claims] 1. A recording ink holding container, an ink supply pipe for supplying the ink held in the recording ink holding container to a recording nozzle, and ink ejected from the recording nozzle that is not used for recording. An ink collection means for collecting and returning the ink to the recording ink holding container; and an ink supply pipe connected to the ink supply pipe via an ink supply valve in the middle of the supply ink holding container. An ink jet recording apparatus comprising: an ink supply unit that supplies ink to a tube; wherein the ink supply unit returns a supply ink flowing through the ink supply tube to the supply ink holding container; An ink circulation device for an ink jet recording apparatus, comprising: a supply ink circulation valve provided in the middle of a supply ink circulation tube. 2. The ink circulation device according to claim 1, wherein a supply ink circulation tube of said ink supply means branches off from said ink supply tube. 3. The ink circulation device according to claim 1, wherein a replenishment ink circulation tube of the ink replenishment unit branches off from the ink supply tube. 4. The ink circulation device according to claim 2, wherein the ink supply means includes a supply ink circulation pump in the supply ink circulation pipe. 5. An ink supply container for recording, an ink supply pipe for supplying ink retained in the ink supply container to a recording nozzle, and an ink supply valve interposed in the ink supply pipe in the following order: And an ink supply pump; an ink recovery means for recovering ink that has not been used for printing among the ink ejected from the printing nozzles and returning the ink to the printing ink holding container; An ink supply unit connected to the ink supply tube downstream of the ink supply valve via a supply valve, and an ink supply unit for supplying ink to the ink supply tube; and a control device for controlling these units. In the ink jet recording apparatus, the ink replenishing means may recirculate replenishing ink flowing through the ink supply pipe to the replenishing ink holding container. When the ink circulation apparatus of an ink jet recording apparatus characterized by comprising a replenishment ink circulation valve interposed in the middle of the replenishment ink circulation tube. 6. The ink circulating device according to claim 5, wherein a replenishing ink circulating tube of said ink replenishing means branches off from said ink replenishing tube. 7. The ink circulating apparatus according to claim 5, wherein a replenishing ink circulating pipe of said ink replenishing means branches off from said ink supplying pipe. 8. The ink replenishing means according to claim 6, wherein said ink replenishing means includes a replenishing ink circulating pump in the middle of said replenishing ink circulating pipe, and wherein said control device replenishes ink in a state in which an ink supply valve is closed. An ink circulation device for an ink jet recording apparatus, wherein a valve and a supply ink circulation valve are opened to operate a supply ink circulation pump.