DE3448421C2 - Ink jet printer with ink container in second container - Google Patents

Abstract

The ink jet print head is supplied with paper across the front plate. A top plate supports seven head units across the width of the unit to present a full print time capacity. A distributor provides the flow and return paths from the heads to a supply.The head is mounted on a main plate that provides support for an ink reservoir supplying the distributor. This is in turn coupled to a main ink cassette supported on a guide. A pump operates together with three solenoid actuated valves selectively operated to provide print, ink transfer, circulation and nozzle evacuation operations

Description

The invention relates to an ink jet recording device according to the preamble of claim 1.

Such an ink jet is known from DE-PS 27 24 548 Recorder known in which the ink by means of a Pump through a second ink flow path to the recording head is expelled. In circulating mode, ink is drawn from the ink reservoir using the same pump via the second ink flow path to the recording head and back to the ink reservoir via a first flow path promoted. With such printers it can happen that in the area of Discharge openings and the feed lines to the recording head Air accumulates, the proper supply of the ink to the discharge openings. To get the air out of the Removing the pipe system is a cleaning operation of the Ink jet recording apparatus provided in which the Ink with the air pockets by means of the pump over a second feed line is conveyable back to the ink tank. The delivery pressure of the pump is chosen so that the Ink does not come out of the nozzles of the recording head. The pump must therefore be designed so that it on the one hand generated enough pressure to get a proper one Write operation of the ink jet recording device guarantee and on the other hand the pressure on a for suitable level can be reduced. To meet these requirements, a must for the pump complicated control system can be provided. Furthermore such a device is not suitable for Clogging in the ejection area of the recording head remove.  

From DE-OS 29 16 881 is an ink jet recording head known, in which the ink over two Supply lines with one pump each from an ink tank is conveyable to the recording head. In the cleaning company the pump delivery direction can be reversed, so there is the ink in the reverse direction from the recording head is suctioned off. With such a device the ink in the area of the recording head completely removed and air sucked in through the discharge openings, so that the leads to the printhead at the beginning of the Must first be filled with ink.

In DE-OS 27 15 189 is an ink jet recording device shown, in which the ink in the printing operation over the Capillary action of the leads to the recording head is promoted and in which a flushing operation is provided, in the ink from a second pressurized ink tank via a lockable branch line for rinsing of the recording head can be supplied with an increased pressure is so that the ink and possibly impurities from the discharge openings depending on the container pressure is expelled. Such a structure does not allow Cleaning operation in which the ink in the piping system between the ink tank and the recording head becomes. In addition, each recording head must have its own Supply line assigned to the pressurized Ink tank leads, resulting in the construction of the apparatus is significantly increased.

An ink supply system is known from DE 32 47 875 A1 known for an ink jet printer in which a pump only serves to check the ink level in the main tank and thereby change or increase the ink pressure to to initiate a cleaning rinse cycle in which Ink through the nozzles of the inkjet head is pushed through. With this system, Recording operation the ink from the Ink reservoir through a line to the printhead fed, in which there is no pump.

The from the above publications known facilities do not have the disadvantages of generic ink jet recording device overcome.

The invention is based, with reduction of the device complexity, an inkjet To create a recording device, at all times a proper Printing operation is guaranteed in a simple manner.  

This object is achieved by the features of Claim 1 solved.

The construction according to the invention enables the pump only in the processing mode of the ink jet recording device is used, d. i.e. when the recording head rinsed or the ink circulated in the supply system becomes. This takes place in regular recording mode Capillary action supplies ink to the recording head in the flow paths. Since the pump is in recording mode does not take over a function, it only has to to the special requirements of the processing company be designed. By suitable actuation of the switching device and the reversibility of the pump delivery direction can be used both for flushing the recording head and also for conveying ink and air pockets from Recording head can be used towards the ink tank.

Advantageous developments of the invention are the subject of subclaims.

Preferred embodiments of the invention are in following explained with reference to the drawings. It shows

Fig. 1 is a perspective view of an ink jet recording apparatus;

Fig. 2 is a partially broken perspective view of a head assembly on an enlarged scale, which has a distributor;

Figs. 3A to 3E items of the manifold in a top view;

FIG. 4 is a liquid circuit diagram for an ink supply system of the ink jet recording apparatus of FIG. 1.

Fig. 1 shows the main components of an ink jet recording apparatus designed according to the invention. The present embodiment is directed to a four-color ink jet printer having a plurality of print heads arranged in the width direction of a recording paper and printing on demand.

In Fig. 1, a recording paper P which is fed in the direction of arrow f and an apparatus plate 2 are shown. On the front and back of the apparatus plate 2 , seven head members 4 are attached over the entire width of the recording surface of the paper P, each of which has 128 discharge openings arranged in the width direction and opposite to the recording paper P. These head members 4 are appropriately attached to both surfaces of the apparatus board 2 so that the recording areas of the discharge ports of the front head members 4 and the recording areas of the discharge ports of the rear head members 4 do not overlap and achieve a single print line. In the recording mode, the bottom or rear head components are operated first, and if the described area for comparison with the top or front head components comes in the direction of arrow f when the recording paper P is fed, then these front head components are operated so that a single line is printed.

A distributor 6 comprises a flow distributor 6 A (s. Fig. 3C) for supplying ink to the head component 4 via a supply line 8 A and a return manifold 6 B (s. Fig. 3C) for recovering the ink from the head members via a supply line 8 B. A connector 7 (D connector) connects the distributor 6 to the supply line 8 . These components represent a head assembly 10 for one ink color, and in the embodiment in question four of these head assemblies 10 - one for each ink color - are used.

Fig. 1 further shows a main panel 20, a guide member 22, the module 10 performs the device board 2 for mounting the head on the main panel 20, and a first container 30 which forms an ink supply source for the head parts 4 and the ink receiving and is arranged on the side of the main panel 20 opposite the head assembly 10 . A second container 40 is a type of ink cartridge or cartridge container which is guided by a guide member 24 on the main panel 20 for mounting thereon. The first container 30 is equipped with a liquid level sensor, and when it detects that the amount of ink in the first container has fallen below a predetermined amount, ink is transferred from the second container 40 to the first container 30 . On the first container 30 there are arms 32 and 34 , and on the arm 32 serving as opening / shut-off devices 50 and 52 , z. B. solenoid valves, and on the second arm 34, a switching device 54 , z. B. a solenoid valve and a pump 56 are arranged. Shut-off valves or slide valves can also be used as switching devices 50, 52 and 54 instead of solenoid valves.

The solenoid valve 50 on the arm 32 has a valve piston 50 A, which has a (see also FIG. 4) pipeline 60 which leads to the ink space in the first container 30 and forms a first ink flow path, with a connecting element 70 (DV connecting element) which through the main panel 20 leads to the distributor 6 A, connects. When a solenoid 50 B is energized, the valve piston 50 A is brought into the open position so that a flow path for the ink is formed. The solenoid valve 52 has a valve piston 52 A, through which an air flow in the first container 30 can be connected to the atmosphere. The valve piston 52 A is brought into the open position when a solenoid 52 B is excited, whereby the air space in the first container 30 is opened to the atmosphere. On the atmosphere side of the valve piston 52 A, a dust filter can be disposed at a vent hole 53 (s. Fig. 4).

The solenoid valve 54 attached to the arm 34 has a valve piston 54 A, which connects a connecting member 72 , which connects a pipe 64 leading to the pump 56 to a pipe 66 leading to the second container 40 and forms a second ink flow path, with a DV connecting member 74 , which extends through the main panel 20 to the distributor 6 B connects. A TC connector 76 connects the pipeline 66 to the second tank 40 .

The pump 56 has a connection to the second container via the pipe 64 leading to the solenoid valve 54 and is connected via the pipe 68 lying in the second ink flow path and a device preventing a backflow, e.g. B. a check valve connected to the first container 30 . Depending on the forward or reverse operation of the pump 56 , this ink conveys from the second container 40 through the valve piston opening 54 A to the first container 30 or to the valve piston opening 54 A.

The components 30, 40, 50, 52, 54 and 56 form an ink supply stage for the head assembly 10 . In the ink jet printer shown in Fig. 1, four such stages - one for each ink color - are provided, although only one is shown in Fig. 1 in order not to make the illustration too complex. The ink supply stage is connected to the head assembly 10 via the DV connectors 70 and 74 , which will be discussed in more detail later.

On the main panel 20 , a coupling piece 80 is attached for connection to a control unit (not shown). An interface plate 82 and a flexible wiring plate 84 serve to transmit a pressure control signal supplied from the control unit via the coupling piece 80 and the interface plate 82 to the head components 4 .

In the ink jet printer, since the head assembly 10 , the ink supply stage, and the electrical wiring are connected to and around the main board, the removal of each assembly is easy.

Referring to Figs. 2 and 3 of the distributor 6, the head assembly 10 will now be described having a top plate and a bottom plate 6-1 6-5 the fixing surfaces have 6-1 and 6-5 A A for attachment to the plate 2 units . The sealing plates 6-2 and 6-4 (see FIGS. 3B and 3D) are made of rubber, for example. A distributor main part 6-3 (see FIG. 3C) is provided with the tubular distributors 6 A and 6 B, in which ink supply chambers 6-3 A and 6-3 B are formed, which correspond to the supply lines 8 A and 8 B. . The cover plate 6-1 , the bottom plate 6-5 and the sealing plates 6-2 and 6-4 are perforated in accordance with perforations in the storage chambers 6-3 A and 6-3 B to form the ink supply path to the DT connector 7 . The arrangement with regard to the correspondence between the storage chambers and the perforations is indicated in FIG. 3 by the dashed lines.

The connections of the lines for the ink supply path can by the arrangement of the distributor to the head components be simplified.

Figure 4 shows an ink supply system with a head assembly and an ink supply stage. A check valve 58 is arranged on the TC connector 76 ( FIG. 1), which connects the second container 40 to the pipeline 66 , which only allows the ink flow in a direction leading away from the container 40 . Arrows F and R show the directions of ink flow when the pump 56 is running forward and backward, respectively. An ink supply I and an air space are present in the first container 30 .

By controlling the pump 56 and the open and closed states of the solenoid valves 50, 52 and 54 , the ink supply system can be brought into an operating state shown in the following table.

Table 1

The respective operating modes and the ink flow in the the respective operating modes are explained below.

1. Write operation

Ink required for writing or printing is supplied to the head component 4 from the first container 30 . Since the present embodiment is directed to an on demand ink jet printer, the ink is not pressurized during printing, ie the pump 56 is not powered.

In printing operation, the ink is expelled from the head component 4 after it has been supplied to it via the solenoid valve 50 with piston 50 A, via the DV connecting element 70 , the distributor 3 A and the supply line 8 A.

2. Feed operation

In the supply mode, the ink is supplied from the second container (ink cartridge container) 40 to the first container. This mode of operation is used at the beginning of the use of the ink jet printer and when the amount of ink in the first container 30 decreases.

In this operating mode, the valve piston 52 A is brought into the open position, the valve piston 54 A into the closed position, and the pump 56 is operated in the forward direction. Accordingly, ink is conveyed from the second container 40 through the check valve 58 , the line 64 , the pump 56 and the line 68 in the direction V into the first container 30 , so that the liquid level rises therein.

3. Circulation mode

Circulation is used when ink is used Supply of the heads when the printer is used for the first time is to be circulated or when air bubbles in the heads or Supply lines should be eliminated and the ink to be renewed in it. This operating mode also comes then used when the printer is after a long time Downtime is put back into use.

In this operating mode, the valves 50, 52 and 54 are opened, the ink flows in the direction R from the first container 30 through the line 68 , the pump 56 , the line 64 , the valve 54 , the DV connector 72 , the distributor 3 B, the supply line 8 B, the head 4 , the DV connector 70 , the valve 50 with piston 50 A and the pipeline 60 back to the first container 30 . The air bubbles from the heads 4 or the supply lines are caught in the first container 30 and discharged from the air space A via the open valve piston 52 A to the atmosphere.

4. Printing (flushing) operation

When the outlet openings of the heads 4 are dried or clogged, the ink is pressurized so that it is forcibly ejected from the openings to remove blockages.

In this operating mode, valve 50 is closed, valves 52 and 54 are opened, pump 56 is operated in reverse. Accordingly, the ink is supplied from the first container 30 in the direction R through the line 68 , the pump 56 , the line 64 , the valve 54 , the DV connector 72 , the distributor 3 B and the supply line 8 B to the heads 4 .

5. Storage mode

The storage operation prevents volatilization and denaturation of the ink in the first container 30 as well as leakage or flow of ink. This mode is used when not printing or when the printer is being transported.

In this operating mode, the valve pistons 50 A, 52 A and 54 A are brought into the closed positions, the pump 56 is stopped. As a result, there is no ink flowing in the supply network and ink cannot escape from the printer. Since all valves are closed, there is no risk of environmental or atmospheric conditions, e.g. B. temperature changes, based leakage of ink contained in the container through a head or an entry of air and / or dust into the supply network.

As has been described, the ink jet recorder is with a first container as an ink supply source, with a second, a source of supply for the container forming the first container, with three switching devices and equipped with a reversible pump. The open and closed states of the switching devices and the operating state of the pump are controlled that a feed or feed, a pressure, a circulation and a store operation in addition to a write operation can be adjusted. As a result, it becomes an ink jet printer of simple construction and high reliability receive.

Claims (4)

An ink jet recording apparatus having a recording head ( 4 ) and an ink tank ( 30 ) which are connected in a circuit by means of a first ink flow path ( 60, 70 ) and a second ink flow path ( 68, 64, 72 ), at least the first ink flow path is provided with an opening / shutting-off device ( 50 ) and the second ink flow path is provided with a pump ( 56 ), and the pump for conveying ink from the ink container ( 30 ) to the recording head ( 4 ) can be operated via the first ink flow path back into the ink container, thereby characterized in that the first ink flow path ( 60, 70 ) is an ink supply path during the recording operation. 2. Ink jet recording device according to claim 1, characterized in that the ink container ( 30 ) has a ventilation opening ( 53 ) to the ambient air. 3. Ink jet recording device according to claim 1 or 2, characterized in that the opening / shut-off device ( 50 ) can be closed in a flushing operation, in which ink is forced from the ink container ( 30 ), the second ink flow path ( 68, 64, 72 ) with the Pump ( 56 ) and the recording head ( 4 ) can be fed and ink can be extracted from the discharge opening of the recording head ( 4 ). 4. Ink jet recording device according to claim 2 or 3, characterized in that the first and second ink flow paths ( 60, 70; 68, 64, 72 ) and the vent opening ( 53 ) can be blocked.