JPH05177843A - Head mechanism of ink jet type printer - Google Patents

Abstract

PURPOSE:To prevent the clogging of a nozzle orifice and to prevent the printing inferiority accompanied by said clogging by providing a control unit receiving a printing command to supply control flow to a fluid element and alternately changing over the passages of ink in the fluid element. CONSTITUTION:The diameter of each of nozzle orifices 5 is set to about 0.05-0.1mm and the diameter of each of the input and output passages 1a-1c is also reduced to about 0.05-0.1mm. The fluid element 1 is controlled by a control unit 7 and the control unit 7 is equipped with a controller 74 controlling an air compressor 71, the air supply passage 72 connected to the compressor 71, the clossure valves 73 provided to the air supply passage 72 and the controller 74 controlling the opening and closing of the respective closure valves 73. When a printing command is issued, control flow is supplied to the fluid element 1 and the passages of ink in the fluid element are alternately changed over by two output passages 1b, 1c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer head mechanism, and more particularly to an ink jet printer head mechanism using a fluid element.

[0002]

2. Description of the Related Art FIG. 4 is a conceptual diagram showing an example of a head mechanism of a conventional ink jet printer. 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,
The ink in the pressure chamber 105 is pressurized by, for example, the electrostrictive element 106 and ejected from the nozzle holes 107 toward the paper.

The ink supply path 103 is branched downstream of the pump 102, and in order to prevent ink from being supplied to the pressurizing chamber 105 and the nozzle hole 107 which do not require ink replenishment in each branch flow path, A valve 109 opened and closed by the control device 108 is interposed.

The pressure chamber 10 is replaced with the electrostrictive element 106.
A heater for instantaneously boiling the ink in the nozzle 5 is provided, and the ink is ejected by the pressure of the bubble that grows with the boiling of the ink.
There is also a configuration in which the ink is ejected from 07 toward the paper.

[0005]

In the head mechanism of these conventional ink jet printers, the valve 1 is used.
Although new ink flows through the pressurizing chamber 105 and the nozzle hole 107 connected to the branch flow passage in which 09 is opened, the pressurizing chamber 105 and the nozzle connected to the branch flow passage in which the valve 109 is closed for a long period of time. Ink stagnates and stagnates in the holes 107, the ink is solidified and the nozzle holes 107 are clogged, and when the valve 109 is subsequently opened, the ink is not sufficiently ejected, and print defects such as a decrease in print density and blurring occur. Sometimes. In addition, when the ink clogged in the nozzle holes 107 is ejected at the time of the next printing, an excessive amount of ink may be ejected, which may cause a printing defect called fluffing.

Further, when the electrostrictive element 106 or the heater is used, it is necessary to control the timing of operating the valve 109 and the electrostrictive element 106 or the heater, which causes a problem that the configuration of the control device 108 becomes complicated. is there.

The present invention has been made in view of the above circumstances, and it is possible to prevent clogging of nozzle holes and the occurrence of defective printing, and further, to simplify the structure of the control device. It is an object to provide a head mechanism of a printer.

[0008]

In order to achieve the above-mentioned object, the present invention comprises, for example, as shown in FIG. 1, one input channel 1a and two output channels 1b and 1c, and A head H, which is a collection of fluid elements 1 having nozzle holes 5 that communicate with one of the output channels 1b and ejects ink on the front surface of the main body, and guides the ink in an ink bottle 2 to the input channels 1a of each fluid element 1. , A supply / recirculation mechanism 10 that supplies and recirculates again from the ink supply path 3 to the input flow path 1a via the other output flow path 1c, and a fluid flow by supplying a control flow to the fluid element 1 in response to a print command. A control device 7 that alternately switches the ink flow paths inside is provided.

Further, the supply and 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 composed of a recirculation path 6 which communicates with the ink bottle 2 or the ink supply path 3 on the upstream side of the pump 4.

Further, the fluid element 1 may be a bistable element, a monostable element, or a half addition element.

[0011]

The ink supplied from the ink bottle 2 to the fluid element 1 is not interrupted, and the output passage 1b on the nozzle hole 5 side is not interrupted.
Alternatively, it may flow into the output flow path 1c on the side of the return flow path 6 and the nozzle hole 5
When the ink flows to the paper from the nozzle hole 5 when flowing to the output flow path 1b on the side, the ink flows from the return path 6, the ink bottle 2 or the pump 4 when flowing to the output flow path 1c on the return path 6 side. Also, a portion of the ink supply passage 3 on the upstream side, a portion of the ink supply passage 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 an embodiment of the present invention. The printer head H is composed of the same number of fluid elements 1 arranged horizontally (or vertically) as the number of dots arranged horizontally (or vertically) in one character, and each fluid element 1 is connected to one input flow path 1a and 2 respectively. It is provided with one output flow path 1b, 1c.

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

Further, one output flow path 1 of the fluid element 1 is provided.
b is connected to the nozzle hole 5 formed on the surface of the main body, and the other output flow path 1c is connected to the main flow path 3a of the ink supply path 3 on the upstream side of the pump 4 via the return path 6. As a result, the pump 4 constitutes the supply / recirculation mechanism 10 in which the ink from the ink bottle 2 is supplied and recirculated through the supply passage 3, the input passage 1 a, the output passage 1 c, and the return passage 6.

The diameter of the nozzle hole 5 is set to about 0.05 to 0.1 mm. Therefore, the input and output flow paths 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 controller 7, which includes an air compressor 71, an air supply path 72 connected to the air compressor 71, a stop valve 73 interposed in the air supply path 72, and each stop valve. 73
The controller 74 is provided to control the opening and closing. As a result, when the above print command is issued, a 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. ..

Each fluid element 1 has two control channels 1d, 1e.
And the air supply path 72 is branched to form each control flow path 1d,
1e is connected. In addition, the stop valve 73 is provided in the branch flow passage 71a connected to the control flow passages 1d and 1e of each fluid element 1.
Each one is intervening.

At the start of the printing process, the control device 7 stops the pump 4 and then supplies air to both the control flow paths 1d and 1e to control the ink flow path in the fluid element 1, particularly one control. The flow path 1d and the nozzle hole 5 are pre-purged.

In this printer, control air is instantaneously and alternately supplied from the control device 7 to the two control flow paths 1d and 1e of each fluid element 1. As a result, the ink that has flowed in from the input flow path 1a is supplied with the control air and is supplied to the control flow path 1a.
The direction is switched to the output flow path 1b or 1c on the opposite side of d, 1e, and the ink is ejected from the nozzle hole 5 or 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 side at the same time when the supply of the control air is started, and thereafter the control air is supplied to the control flow path 1e. That state is retained. Further, when the control air is supplied to the control flow path 1e in this state, the ink flow is switched to the nozzle hole 5 side at the same time as the supply of the control air is started, and then the control air is supplied to the control flow path 1d. That state is retained. Therefore, in this case, each fluid element 1 can be said to be a bistable element.

As a result, the ink is flowed without interruption when ejected from the nozzle hole 5 and when it is not ejected, and the ink is not stagnant and stagnant in the fluid element 1. As a result, there is no risk that the ink will solidify in the fluid element 1, and there is no risk that the nozzle holes 5 will become clogged. As a result, it is possible to prevent a print defect due to a lack of ink such as a decrease in print density and blurring, or a print defect due to an excess of ink such as dripping.

Further, since the ink flows in the ink supply passage 3 and the return passage 6 without interruption, there is no possibility that the ink will stagnate and solidify in the ink supply passage 3 and the return passage 6 as well.

Further, since the control device 7 needs to control only the timing for switching the direction of the ink flow in the fluid element 1 by opening the respective shutoff valves 73, the control device 7, particularly the controller 74, can be configured simply. 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 to make the fluid element 1 thinner, the control accuracy of the ink flow is enhanced, so that the number of dots is increased. The higher the printing resolution, the higher the accuracy of ink flow control 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 head mechanism of the ink jet printer in this case uses the fluid element 1 formed of a monostable element instead of the bistable element. Therefore, the number of control flow paths 1d in the fluid element 1 is one, and one vent 1f is provided for discharging the control air to the outside of the fluid element 1.

In this printer, the 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, it flows to the side of the return path 6. Also,
The number of branches of the air supply passage 72 and the number of shutoff valves 73 of the control device 7 may be half of those in the embodiment shown in FIG. 1, and the configuration is simplified.

Since the other construction, operation and effect of this printer are the same as those of the embodiment shown in FIG. 1, the description thereof will be omitted. Further, in FIG. 2, the same reference numerals and names as those in FIG. 1 are given to the respective parts corresponding to the respective parts shown in FIG.

FIG. 3 is a conceptual diagram showing another embodiment of the present invention. In this case, the head mechanism of the ink jet printer uses the fluid element 1 formed of a half addition element instead of the bistable element or the monostable element. The fluid element 1 includes an input flow path 1a, two output flow paths 1b and 1c,
It has one control flow path 1e.

A control ink branch flow path 75 branched from the downstream side of the pump 4 of the ink supply path 3 to the control flow path 1e.
Is connected, and the controller 74 of the control device 7 is configured to control opening / closing of the stop valve 73 interposed in each control ink branch flow path 75.

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

With this configuration, the compressor 71 and the air supply passage 72 shown in FIGS. 1 and 2 can be omitted.
Simpler configuration. Other configurations of this embodiment,
Since the operation or effect is similar to that of the embodiment shown in FIG.
These explanations are omitted to avoid duplication. Also, FIG.
In FIG. 2, each part corresponding to each part shown in FIG. 2 is assigned the same reference numeral and name as in FIG.

[0031]

As described above, in the head mechanism of the ink jet printer of the present invention, the fluid element is used so that the ink continues to flow without stagnation. Therefore, it is possible to prevent the ink from solidifying due to the stagnation of the ink. It is possible to prevent the stagnant ink from clogging the nozzle holes. as a result,
Insufficient or excessive ink ejection amount is prevented, and printing quality is improved.

Further, since the control device may be constructed so as to control only the timing of switching the direction of ink flow in the fluid element, the structure 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 ink flow 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 done at high speed.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an 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 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 Reflux Path 7 Control Unit 10 Supply / Reflux Mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiji Atsumi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (5)

[Claims] 1. An input flow path (1a) and two output flow paths
(1b) and (1c), and a head (H) in which a fluid element (1) having a nozzle hole (5) communicating with one of the output channels (1b) on the front surface of the main body and ejecting ink is assembled. ) And the ink in the ink bottle (2) to the input flow path of each fluid element (1).
(1a), and from the ink supply path (3) to the other output flow path (1
The ink in the fluid element (1) is supplied by supplying a control flow to the fluid element (1) in response to a print command and a supply recirculation mechanism (10) that recirculates to the input flow path (1a) via c). And a controller (7) for alternately switching the flow paths of the head mechanism of the ink jet printer. 2. The ink bottle is provided with the supply / reflux mechanism (10).
The ink supply path (3) that guides the ink of (2) to the input flow path (1a) of each fluid element (1), the pump (4) interposed in the ink supply path (3), and the fluid element (1) 2. The ink jet system according to claim 1, further comprising a return passage (6) for communicating the other output passage (1c) of the above with an ink bottle (2) or an ink supply passage (3) upstream of the pump (4). Printer head mechanism. 3. The head mechanism of an ink jet printer according to claim 1, wherein the fluid element (1) is composed of a bistable element. 4. The head mechanism of an ink jet printer according to claim 1, wherein the fluid element (1) is composed of a monostable element. 5. The ink jet printer head mechanism according to claim 1, wherein the fluid element (1) is constituted by a half-summing element.