JP2706196B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ink jet recording apparatus.
Printing apparatus , particularly an ink jet recording apparatus using a fluid element.
It is related to the location .

[0002]

2. Description of the Related Art FIG. 4 is a conceptual diagram showing an example of a conventional ink jet recording apparatus . The ink in the ink bottle 101 is supplied to the pressurizing chamber 105 in the head 104 through the ink supply path 103 with the pump 102 interposed therebetween, and the ink in the pressurizing chamber 105 is pressurized by, for example, the electrostrictive element 106 to form the nozzle hole 1.
07 to the paper.

The ink supply path 103 is branched downstream of the pump 102. Each of the branch paths is provided to prevent the supply of ink to the pressurizing chamber 105 and the nozzle hole 107 which does not require replenishment of ink. A valve 109 which is opened and closed by the control device 108 is interposed.

Further, instead of the electrostrictive element 106, a pressure chamber 10
5 is provided with a heater for instantaneously boiling the ink in the nozzle hole 5.
There is also a configuration in which ejection is performed from 07 to a sheet.

[0005]

In these conventional ink jet recording apparatuses , the pressurizing chamber 105 and the nozzle hole 107 connected to the branch flow path in which the valve 109 is opened.
, New ink flows, but the pressurized chamber 105 connected to the branch flow path with the valve 109 closed for a long period of time.
In addition, the ink stagnates and stagnates in the nozzle hole 107, the ink solidifies, and the nozzle hole 107 is clogged.
When the opening 09 is opened, ink is not sufficiently ejected, and a printing defect such as a decrease in print density and blurring may occur. Further, an excessive amount of ink is ejected by ejecting the ink clogged in the nozzle hole 107 at the time of the next printing, and a printing defect called dropping may occur.

Further, when the electrostrictive element 106 and the heater are used, it is necessary to control the timing at which the valve 109 and the electrostrictive element 106 or the heater are operated, and the configuration of the control device 108 becomes complicated. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an ink jet recording apparatus capable of preventing clogging of a nozzle hole and occurrence of a printing failure due to the clogging, and simplifying the configuration of a control device. It is intended to provide a device .

[0008]

In order to achieve the above object, the present invention comprises one input flow path 1a and two output flow paths 1b and 1c as shown in FIG. A head H in which fluid elements 1 having nozzle holes 5 communicating with one output flow path 1b on the front surface of the main body and ejecting ink are collected, and ink in the ink bottle 2 is guided to the input flow path 1a of each fluid element 1. A supply recirculation mechanism 10 for recirculating the ink from the ink supply path 3 to the input flow path 1a via the other output flow path 1c ;
In the middle of the two output channels 1b and 1c from the input channel 1a
Supply of a control medium through a control flow path opening to
Ink flow that alternately switches between the two output flow paths
Is provided with a control device that forms

The supply recirculation mechanism 10 includes an ink supply path 3 for guiding the ink in the ink bottle 2 to the input flow path 1a of each fluid element 1, a pump 4 interposed in the ink supply path 3, and a fluid The other output flow path 1c of the element 1 is constituted by a reflux path 6 that communicates with the ink supply path 3 upstream of the ink bottle 2 or the pump 4.

Further, the fluid element 1 may be any of a bistable element, a monostable element, and a half-addition element.

[0011]

The ink supplied from the ink bottle 2 to the fluid element 1 is not interrupted without interruption.
Alternatively, it flows into the output flow path 1c on the side of the return path 6, and the nozzle hole 5
When the ink flows to the paper through the nozzle hole 5 when the ink flows into the output flow path 1b on the side, the ink flows from the ink path 2 and the pump 4 when the ink flows to the output flow path 1c on the side of the return path 6. Also, a part of the ink supply path 3 on the upstream side, a part of the ink supply path 3 on the downstream side of the pump 4 and the fluid element 1
Will be circulated.

[0012]

FIG. 1 is a conceptual diagram showing one embodiment of the present invention. The printer head H is formed by connecting horizontally (or vertically) the same number of fluid elements 1 as the number of dots arranged horizontally (or vertically) in one character, and each fluid element 1 has one input flow path 1a and one input flow path 2a. It has two output channels 1b and 1c.

An input flow path 1a of the fluid element 1 is connected to an ink bottle 2 via an ink supply path 3, and the ink supply path 3 is connected to a main flow path 3a with a pump 4
And a branch flow path 3b branched on the downstream side.

Also, one output flow path 1 of the fluid element 1
b is communicated with a nozzle hole 5 formed on the surface of the main body, and the other output flow path 1c is communicated with a main flow path 3a of the ink supply path 3 at an upstream side of the pump 4 via a return path 6. Thus, the pump 4 constitutes a supply recirculation mechanism 10 in which ink from the ink bottle 2 is supplied and recirculated through the supply path 3, the input flow path 1a, the output flow path 1c, and the return path 6.

The diameter of the nozzle hole 5 is set to about 0.05 to 0.1 mm. Therefore, the input and output channels 1a to 1c in the fluid element 1 are also reduced to about 0.05 to 0.1 mm. be able to. The liquid element 1 is controlled by a control device 7, which controls the air compressor 71, an air supply passage 72 connected to the air compressor 71, a shutoff valve 73 interposed in the air supply passage 72, and each shutoff valve. 73
And a controller 74 for controlling the opening and closing of the controller. Thus, when the print command is issued, the control flow is supplied to the fluid element 1 and the ink flow path in the fluid element 1 is alternately switched between the two output paths 1b and 1c as described below. .

The fluid element 1 is used for the ink in the fluid element 1.
From the input flow path 1a to the two output flow paths 1b, 1c
Drawing of the ink flow at a right angle to the ink flow on the way
The air supply path 72 is divided into two control flow paths 1d and 1e, each of which is open from the upper and lower sides.
Connected to. The closing valves 73 are interposed one by one in the branch flow paths 71a connected to the control flow paths 1d and 1e of each fluid element 1.

At the start of the printing process, the control device 7 stops the pump 4 and then supplies air to the two control channels 1d and 1e to supply ink to the ink channel in the fluid element 1, especially one of the control channels. It is configured to perform pre-purge of the flow path 1d and the nozzle hole 5.

[0018] In this printer, the two control passages 1d of each fluid element 1 from the control device 7, momentarily braking alternately 1e
Air as a control medium is supplied. As a result, the ink flowing from the input flow path 1a is output from the output flow path 1b or 1b opposite to the control flow paths 1d and 1e to which the control air is supplied.
c, the direction can be switched,
The ink is returned to the main flow path 3a of the ink supply path 3 via the return path 6.

That is, when the control air is supplied to the control flow path 1d, the ink flow is switched to the recirculation path 6 simultaneously with the start of the supply, and thereafter, until the control air is supplied to the control flow path 1e. That state is maintained. When the control air is supplied to the control channel 1e in this state, the ink flow is switched to the nozzle hole 5 simultaneously with the start of the supply, and thereafter, the control air is supplied to the control channel 1d. That state is maintained. Therefore, in this case, each fluid element 1 can be said to be a bistable element.

As a result, the ink flows without interruption when it is ejected from the nozzle hole 5 and when it is not ejected, so that the ink does not stagnate and stay in the fluid element 1. As a result, there is no possibility that the ink solidifies in the fluid element 1 and there is no possibility that the nozzle hole 5 becomes clogged. As a result, it is possible to prevent a printing failure due to a shortage of ink such as a decrease in print density and a blur, and a printing failure due to an excessive amount of ink such as dropping.

In addition, since the ink flows in the ink supply path 3 and the return path 6 without interruption, there is no possibility that the ink will stagnate and solidify in the ink supply path 3 and the return path 6.

Furthermore, since the control device 7 only needs to open each of the shut-off valves 73 and control only the timing of switching the direction of the ink flow in the fluid element 1, the configuration of the control device 7, especially the controller 74, can be simplified. can do.

Further, as the diameter of each of the input and output flow paths 1a to 1c in the fluid element 1 is made thinner and the fluid element 1 is made thinner, the control accuracy of the ink flow is increased, so that the number of dots is increased. The higher the printing resolution, the higher the control accuracy of ink flow and the responsiveness of control,
For example, high-resolution printing of about 64 dots can be performed with high accuracy and at high speed.

FIG. 2 is a conceptual diagram showing another embodiment of the present invention. The ink jet recording apparatus in this case uses the fluid element 1 composed of a monostable element instead of the bistable element. Therefore, the fluid element 1 is
From the input flow path 1a to the two output flow paths 1b,
1c, below the ink flow obliquely to the ink flow
One open control flow path 1d is provided , and one event 1f is provided to discharge control air out of the fluid element 1.

In this printer, ink is supplied to the control channel 1
While the control air is supplied to d, it flows to the nozzle hole 5 side,
When the control air is stopped, the air flows toward the return path 6. Also,
The number of branches of the air supply path 72 of the control device 7 and the number of the shut-off valves 73 may be half those of the embodiment shown in FIG. 1 and the configuration is simplified.

The other configuration, operation and effect of this printer are the same as those of the embodiment shown in FIG. 1, and the description thereof will be omitted. Further, in FIG. 2, each part corresponding to each part shown in FIG. 1 is given the same reference numeral and name as in FIG.

FIG. 3 is a conceptual diagram showing another embodiment of the present invention. In this case, the ink jet recording apparatus uses a fluid element 1 composed of a half-addition element instead of a bistable element or a monostable element. The fluid device 1 includes an input channel 1a, 2 two output channels 1b, and 1c, the output channel 1
b, near the branch point of 1c, substantially perpendicular to the ink flow.
And one control flow path 1e that opens from below in the drawing .

The control flow path 1e has a control ink branch flow path 75 branched from the ink supply path 3 downstream of the pump 4.
There are connected, by the controller 74 of the control unit 7 controls the opening and closing of the shut-off valve 73 is interposed to the control ink branch channel 75, the system of the ink as the control medium
It is configured to flow or not to flow to the control channel 1e .

In this printer, when ink is simultaneously introduced from both the input flow path 1a and the control flow path 1e, the ink flows to one of the output flow paths 1b, and the ink flows into the input flow path 1a or the control flow path 1e. When ink is introduced from only one of them, the ink flows to the other output flow path 1c.

With this configuration, the compressor 71 and the air supply path 72 shown in FIGS. 1 and 2 can be omitted.
The configuration can be made simpler. Other configurations of this embodiment,
The operation or effect is the same as that of the embodiment shown in FIG.
These descriptions are omitted to avoid duplication. FIG.
In FIG. 2, the same reference numerals and names as those in FIG. 2 denote the same parts as those shown in FIG.

[0031]

As described above, the ink jet of the present invention is
Since the recording apparatus uses the fluid element to keep the ink flowing without stagnation, it is possible to prevent the ink from hardening due to the stagnation of the ink, and to prevent the stagnated ink from clogging the nozzle holes. As a result, shortage or excess of the ink ejection amount is prevented, and the printing quality is improved.

Further, since the control device may be configured to control only the timing of switching the direction of the ink flow in the fluid element, the configuration of the control device is simplified and the cost can be reduced.

In addition, the thinner the flow path in the fluid element, the closer the flow of the ink becomes to a two-dimensional flow and the higher the control accuracy and responsiveness, so that high-resolution printing can be performed with high accuracy.
And it can be performed at high speed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of one embodiment of the present invention.

FIG. 2 is a conceptual diagram of another embodiment of the present invention.

FIG. 3 is a conceptual diagram of still another embodiment of the present invention.

FIG. 4 is a conceptual diagram of a conventional example.

[Explanation of symbols]

 H Printer head 1 Fluid element 1a Input flow path 1b Output flow path 1c Output flow path 2 Ink bottle 3 Ink supply path 4 Pump 5 Nozzle hole 6 Return path 7 Controller 10 Supply / return mechanism

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiji Atsumi 1015 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-2-107453 (JP, A)

Claims (5)

(57) [Claims] 1. A head comprising one input flow path and two output flow paths, and a fluid element having a nozzle hole on a front surface of a main body and communicating with one output flow path and ejecting ink. The ink in the ink bottle is led to the input channel of each fluid element,
From ink supply channel, the supply recirculation mechanism for supplying a reflux to the input channel again via the other output channels, ink or the input channel of the fluid element receives print command
Through a control channel that opens in the middle of the two output channels
The above two output flow paths by supplying the control medium
An ink jet recording apparatus characterized by a control device for forming an ink flow is switched alternately. 2. The method according to claim 1, wherein the supply recirculation mechanism includes an ink supply path that guides ink in the ink bottle to an input flow path of each fluid element, a pump interposed in the ink supply path, and an ink output path of the fluid element. 2. The ink jet recording apparatus according to claim 1, further comprising a return path communicating with an ink supply path upstream of the bottle or the pump. 3. The method according to claim 1 , wherein said ink is supplied from an ink input passage in a fluid element.
Equipped with two control channels that open in the middle of the two output channels
The air as the control medium is supplied to one of the control channels.
When the ink is supplied, the ink flows to the recirculation path side and the other control
When air as the control medium is supplied to the flow path,
The ink jet recording apparatus according to claim 2 , wherein the ink flows toward the nozzle hole . 4. The method according to claim 1 , wherein said ink is supplied from an ink input passage in said fluid element.
Equipped with one control channel that opens in the middle of two output channels
Then, air as the control medium is supplied to the control flow path.
When this occurs, ink flows to the nozzle hole side and the control medium stops.
3. The ink jet recording apparatus according to claim 2, wherein when stopped, the ink flows toward the return path . 5. A branch of said two output channels in a fluid element.
A single control flow path opening near the point, the input flow path
Ink is used as the control medium in both the control flow path and the control flow path.
When supplied, the ink flows to the nozzle hole side, and the input flow path
Or one of the control channels as the control medium
The ink jet recording apparatus according to claim 2, wherein when the ink is supplied, the ink flows toward the return path .