DE3640032A1 - Printing device - Google Patents

Abstract

A printing device for the dot-by-dot recording of analog patterns or alphanumeric characters and of images on a recording medium using a print head and a printing liquid container and with a printing liquid connection between the print head and the printing liquid container. In order that undesired seeping of the printing liquid from the nozzles of the print head is avoided in a reliable and simple manner, it is proposed according to the invention that the printing liquid connection (4, 7) protrudes into the printing liquid container (3) and is designed in such a way that no static pressure is transmitted onto that end, and that the conveyance of the printing liquid takes place at least partially by capillary effect. <IMAGE>

Description

The invention relates to a writing instrument for point by point Recording of analog courses or alphanumeric Characters and images on a record carrier with a writing head and a writing fluid storage container and a writing fluid connection between the writing head and the writing liquid container.

A writing instrument working with droplets of liquid is known from DE 32 15 608 A1. The printhead has rows of nozzles through which the Writing fluid through piezoelectrically activated Tube is pushed out. With a writing instrument this is the case when the writing fluid level in the Writing fluid container above the writing fluid level in the print head, difficult to avoid, that the static pressure of the writing fluid from Writing fluid container or from the writing fluid connection to the writing fluid in the printhead is transmitted. Too high a static pressure Writing fluid in the print head can cause Unwanted writing fluid out of the nozzles oozes. If the writing instrument when writing over the Record carrier is moved, especially if the Direction of movement of the writing instrument suddenly changed dynamic pressure on the Writing fluid in the writing fluid container exercised. If this over the writing liquid line transferred to the writing fluid in the writing head liquid also oozes out of the nozzles.

The invention has for its object a write to create device of the type mentioned, in which unwanted seepage of the writing fluid the nozzles of the print head safely and easily avoided becomes.

According to the invention, this object is achieved in that the writing fluid connection in the writing fluid protruding container and is designed so that on this end no static pressure is transmitted and that the writing fluid transport is at least partially by capillary action. This will make the static pressure caused by the writing liquid ver writing fluid was not transported onto the binding Transfer existing writing fluid in the print head. Through the writing fluid connection according to the invention between the writing liquid container and the writing head the writing fluid system simultaneously against dynami pressure insensitive.

Further advantages and details of the invention result itself from the subclaims.

The invention is based on two in the Drawings shown embodiments closer explained. Show it

Fig. 1 is a side view of a writing instrument according to the invention and

FIG. 2 shows a side view of a further embodiment of a writing instrument according to FIG. 1.

In Fig. 1 is a cross section through a working with liquid droplets writing instrument ( 1 ) is shown with a closed writing head ( 2 ) which is connected to a writing liquid container ( 3 ). Between the writing liquid container ( 3 ) and the writing head ( 2 ) a U-shaped line ( 4 ) is provided as a writing liquid connection, one end of which is in a tubular holder ( 5 ) and the other end of the writing liquid ( 6 ) of the writing liquid storage container ( 3 ) opens. The line ( 4 ) contains a bundle with continuous glass fibers ( 7 ), which are preferably attached at a distance from one another. At the end of the line ( 4 ), which is attached to the holder ( 5 ), the glass fibers ( 7 ) protrude into the writing head ( 2 ), which is filled with writing fluid ( 8 ).

The writing liquid container ( 3 ) has an opening ( 9 ) for pressure equalization above the liquid level. The opening ( 9 ) has a non-liquid but air-permeable material as the closure ( 15 ). In the event of a change in the position of the writing instrument ( 1 ), writing liquid cannot seep out as a result.

The write head ( 2 ) has a nozzle plate ( 10 ) with conical nozzles ( 11 ). An arcuately curved piezoelectric transducer ( 12 ) is arranged above each nozzle. If a voltage is applied to the transducer ( 12 ), it shortens and changes into the stretched position ( 13 ) shown in broken lines. The writing fluid located between the transducer ( 12 ) and the nozzle plate ( 10 ) is pushed out through the nozzle ( 11 ) in the direction of a recording medium ( 14 ).

Characterized in that the glass fibers ( 7 ) have a high surface energy and the writing fluid has a low surface tension, a large capillary effect is obtained, so that the writing fluid ( 8 ) creeps along the outer walls of the glass fibers ( 7 ) to their ends. The capillary effect creates a connection between the writing fluid ( 8 ) in the writing head ( 2 ) and the writing fluid ( 6 ) in the writing fluid container ( 3 ).

The fact that no static liquid pressure is transmitted to the end of the line ( 4 ) which opens into the writing liquid ( 6 ) of the writing liquid container ( 3 ) and the writing liquid is transported by a pump effect caused by the transducers ( 12 ), the static Pressure of the writing fluid ( 8 ) in the writing head ( 2 ) is not influenced by the transported writing fluid ( 6 ). Writing liquid is now supplied to the writing head ( 2 ) during writing, so that it is always filled. Even if the liquid level (shown in broken lines) in the writing liquid container ( 3 ) is lower than the liquid level in the writing head ( 2 ), writing liquid ( 6 ) is supplied to the writing head ( 2 ) by the pumping action of the transducers ( 12 ).

In Fig. 2 it is shown that the writing fluid container ( 3 ) contains a fiber ball ( 16 ), which is preferably the extension of the glass fibers ( 7 ) present in the line ( 4 ). The glass fibers are preferably closely connected here so that a large capillary effect is created. In this embodiment, the writing liquid container ( 3 ) is not filled with writing liquid, instead writing liquid ( 6 ) adheres to the fibers of the fiber ball ( 16 ).

A connection of the writing fluid ( 8 ) in the writing head ( 2 ) and the writing fluid ( 6 ) of the fiber ball ( 16 ) is carried out in the same way as described in FIG. 1 by capillary action. The writing fluid ( 6 ) from the fiber ball ( 16 ) is transported by the pumping effect of the transducers ( 12 ) via the line ( 4 ) to the writing head ( 2 ).

The fibers ( 7 ) and the fibers of the fiber ball ( 16 ) can also be hollow fibers in this embodiment, so that the total capillary effect is increased.

In the described embodiments, the write head ( 2 ) is preferably filled to the top with writing liquid ( 8 ).

The writing fluid container ( 3 ) may contain another fluid-absorbing material, such as cotton wool, which is saturated with writing fluid instead of a fiber ball ( 16 ).

The glass fiber bundle ( 7 ) in the line ( 4 ) also serves as a filter for filtering dirt particles in the writing fluid ( 6 ).

• 1 writing instrument
  2 printhead
  3 writing fluid containers
  4 line
  5 bracket
  6 writing fluid
  7 glass fiber
  8 writing fluid
  9 opening
  10 nozzle plate
  11 nozzles
  12 converters
  13 extended position of a transducer
  14 record carriers
  15 closure
  16 balls of fiber

Claims (11)

1.Writing device for the point-by-point recording of analog courses or alphanumeric characters as well as images on a recording medium with a writing head and a writing liquid container as well as a writing liquid connection between writing head and writing liquid container, characterized in that the writing liquid connection ( 4 , 7 ) into the writing liquid container ( 3 ) protrudes and is designed so that no static pressure is transmitted to this end and that the writing fluid is transported at least partially by capillary action. 2. Writing implement according to claim 1, characterized in that the writing fluid connection ( 4 , 7 ) consists of at least one fiber ( 4 ). 3. Writing implement according to claim 1, characterized in that the writing fluid connection ( 4 ) consists of a line in which at least one fiber ( 7 ) runs. 4. Writing implement according to one of claims 1 to 3, characterized in that the writing fluid connection ( 4 , 7 ) is approximately U-shaped. 5. Writing implement according to one of claims 1 to 4, characterized in that the writing liquid container ( 3 ) contains a liquid-absorbing material which is connected to the fibers ( 7 ) in the line ( 4 ). 6. Writing implement according to claim 5, characterized ge indicates that as a liquid absorber beer material is provided. 7. Writing implement according to claim 5, characterized in that a fiber ball ( 16 ) is provided as the liquid-absorbing material. 8. Writing implement according to claim 7, characterized in that the fiber ball ( 16 ) consists of the extension of the fibers ( 7 ) present in the line ( 4 ). 9. Writing implement according to one of claims 3 to 8, characterized in that the fibers ( 7 ) are glass fibers. 10. Writing implement according to one of claims 5 to 9, characterized in that the fibers ( 7 ) are hollow fibers. 11. Writing instrument according to one of claims 1 to 10, wherein the writing liquid container has an opening to the atmosphere, characterized in that a non-liquid but air-permeable material ( 15 ) serves as a closure for the opening ( 5 ).