JPS6021258A - Liquid droplet emitting apparatus - Google Patents

Abstract

PURPOSE:To facilitate the control of emission timing, by arranging opposed emitting orifice rows of adjacently arranged liquid droplet emitting heads so as to bring the interval between said orifice rows to the integer-folds of a dot pitch and to one over integer number of the feed pitch of an object to be printed. CONSTITUTION:Each liquid droplet emitting head 1' is driven in a state fixed to a carriage. A liquid droplet emitting apparatus having a width larger than that of an object 7 to be printed is arranged so as to become vertical to the scanning direction of the object 7 to be printed and the mutually adjacent liquid droplet emitting heads 1' are arranged so as to bring the interval l' between the rows of opposed emitting orifices 9 to the integer-folds of a dot pitch and one-integers of the feed pitch of the object 7 to be printed or the integer-folds thereof. By this arrangement, a dot can be printed at an accurate dot pitch only by moving the object 7 to be printed and, in a printer equipped with this liquid droplet emitting apparatus, positional adjustment requiring preciseness between liquid droplet emitting heads, which has been performed by every conventional printer so far, becomes unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a droplet ejection device that performs recording using flying droplets formed by ejecting liquid from an ejection port. Among them, for example, the liquid jet recording device disclosed in German OLS 2944005 facilitates high-speed color recording, and the recording head, which is the main part of the output section, is capable of recording. Because the ejection ports (orifices) for ejecting liquid and forming flying droplets can be arranged in a high density, it is possible to obtain high resolution, and at the same time, the overall performance of the recording head is It is possible to make it compact and suitable for mass production, and furthermore, by fully utilizing the advantages of IC technology and micro-processing technology, which have seen remarkable technological progress and improved reliability in the semiconductor field, it is possible to increase the length and shape of the surface. Recently, it has been attracting a lot of attention because it is easy to convert into two-dimensional images.

However, the required dot pitch density is normally very small, 8 pels or more for 4 pel high image quality, and simply increasing the density of the ejection openings has a technical limit and the durability of the droplet ejecting head. Therefore, it cannot be achieved. Therefore, various techniques have been used in the past, such as using a plurality of droplet ejection heads and arranging the ejection ports of adjacent droplet ejection ports so that the ejection ports are located between the ejection ports of each other.

Furthermore, in conventional droplet ejection heads, it is very difficult to form the nozzles, and for this reason, it has been impossible to supply inexpensive and highly reliable heads in large quantities.

This was a problem that hindered the spread of such printing devices. The cause of this is the diameter of the nozzle, which is several tens of micrometers to several hundred micrometers.
Also, in this type of device, the shape of the nozzle tip greatly influences the characteristics of the droplet ejection head, so the ejection opening must be machined with extremely high precision and with great care. I had to have it. In this case, whether by etching or machining, forming this discharge port and the long flow path following it at the same time requires extremely difficult processing, and is the biggest cause of deterioration of the flow rate. There is. Furthermore, products made through these various processes are subject to rising costs.

Examples of conventional droplet ejecting devices are shown in FIGS. 1, 2, and 6. FIG. 1 is a schematic cross-sectional view of a droplet discharge head, FIG. 2 is a schematic diagram of a droplet discharge device, and FIG. 6 is a view looking at the discharge port side.

In the figure, 1 is the droplet ejection head, 2 is the ejected droplet, 6 is the liquid flow path from the liquid chamber to the ejection port, 4 is the electrothermal converter, 5 is the liquid chamber, 6 is the platen, and 7 is the printed object. The photographic object, IT, is the scanning space of the droplet ejection head, and l is the interval between opposing ejection port rows of the droplet ejection heads that are adjacent to each other.

In a droplet ejection device having a droplet ejection head in which a flow path is formed in the same direction as the ejection direction, as shown in Figs. 1 to 3, the ejection energy is applied to the opposite side of the ejection port. Due to the presence of energy conversion parts, the thickness of the droplet ejection head is thick and uneven, and the presence of connectors makes it impossible to reduce the distance between the droplet ejection heads, and we have also devised ways to fix them. In addition, when the distance between the droplet ejection heads is wide, it is necessary to overlap the ejected dots to create a new halftone or mixed color. There were times when the colors did not mix properly and the colors did not come out as expected.

In addition, since the structure was such that the flow path stood approximately perpendicular to the printing surface, nothing could be placed in the space H scanned by the droplet ejection head during printing. There was a lot of wasted space inside the plane. This resulted in an increase in the size and cost of the machine.

In addition, regarding the installation position, full color requires the installation of multiple droplet ejection heads, and if the positioning is due to mechanical constraints as in the past, it would be difficult to measure the ejection timing from one droplet to the other. It is necessary to generate an independent ejection delay signal for each droplet ejection head, and its control is also complicated.

In addition, the distance l between the opposing ejection opening rows of adjacent droplet ejection heads is determined by their mechanical and structural considerations, and the distance l is not small and may hinder high-density recording. This is the cause.

The present invention has been made in view of the above points, and its main object is to provide a droplet ejection device that is small in size and whose ejection timing can be easily controlled.

Another object of the present invention is to provide a droplet ejection device that increases mass productivity and has low friction.

This objective is achieved by the following droplet ejecting device.

A plurality of ejection ports are provided for ejecting liquid to form flying droplets by using thermal energy, and a plurality of ejection ports are connected to these ejection ports to supply liquid for forming the flying droplets. and a plurality of electrothermal converters serving as means for generating the thermal energy, provided corresponding to each of the discharge ports, and each of the discharge ports In a droplet ejecting device having two or more droplet ejecting heads facing the surface on which the droplet ejecting device is provided, the droplet ejecting device having a width a dog wider than the width of the object to be printed is placed in the direction of scanning the broken object. When arranged perpendicular to the droplet ejection head, the interval between opposing ejection opening rows of adjacent droplet ejection heads is an integer multiple of the dot pitch and an integer multiple of the printing medium feed pitch. 1. A droplet ejecting device characterized in that the droplets are arranged in such a manner that

The droplet ejection device is arranged perpendicular to the scanning direction of the object to be photographed, and the spacing between opposing ejection opening rows of adjacent droplet ejection heads is an integral multiple of the dot pitch and an integer of the object feed pitch. It is preferable to assemble them in advance by arranging them so that they are in the order of - or an integer multiple, and to incorporate them into a printer or the like.

Examples of the present invention are shown in FIGS. 4, 5, 6, and 7. FIG. 4 is a schematic cross-sectional view of the droplet discharge head, and FIG. 5 is a view of the droplet discharge head viewed from the discharge port side. FIG. 6 is a schematic diagram of the droplet discharge device, and FIG. 7 is a view of the droplet discharge device as viewed from the discharge port side. In the figure, 1' is a droplet ejection head whose ejection ports face the surface on which the electrothermal converter is provided, 8 is a liquid supply pipe, 9 is an ejection port, and 2
7 to 7 are as indicated in FIGS. 1 to 6. 4' indicates the scan space of the droplet discharge head, and 4' indicates the interval between opposing rows of discharge ports of adjacent droplet discharge heads.

Although not shown, the droplet ejection head is fixed to a carriage or the like.゛ Driven.

According to the present invention, a droplet ejection device having a width a dog wider than the width of the object to be printed is arranged perpendicular to the scanning direction of the object to be printed, and rows of ejection ports facing each other in the droplet ejection heads adjacent to each other are arranged. By arranging the dots so that the spacing is an integral multiple of the dot pitch and an integral number or an integral multiple of the object feeding pitch, it is possible to print dots at an accurate dot pitch just by moving the object, and In a printer equipped with a droplet ejection device such as the above, there is no need for positional adjustment between a plurality of droplet ejection heads that requires extremely high precision, which was conventionally performed for each printer.

The arrangement space of the droplet ejection device of the present invention is smaller than the scan space H of the conventional droplet ejection device, and the interval l' between the opposing ejection port arrays of the droplet ejection heads that are adjacent to each other is also
As shown in the figure, the size can be reduced by arranging the discharge ports close to each other. Therefore, the device itself can be made compact,
When the apparatus of the present invention is incorporated into a printer, the printing execution section can be brought close to the operator, making it easy to observe the printing state and handle the printed object.

Being able to reduce the spacing l' between the ejection port arrays is also effective in terms of color development and color reproducibility, and the ejection port array 4' is made smaller by an integer multiple of the dot pitch and an integer number of the printing material feed pitch. Alternatively, the discharge control can be simplified by arranging the device to be an integral multiple.

When manufacturing this device, the tip of the discharge port, which requires high-precision machining, and the flow path portion, which does not require precision, can be manufactured separately, and only the tip of the discharge port can be fabricated. It can be manufactured by gluing it together, and whether it is molded or etched, the only place that requires high processing precision is the tip of the discharge port, which can improve mass productivity.

Furthermore, as shown in FIGS. 8 and 19, by combining droplet ejection heads, it is possible to increase the printing area for - times. Note that FIG. 8 shows an example of a droplet ejection device in which four droplet ejection heads are combined, and FIG. 19 is a view of the droplet ejection device as seen from the ejection port side. In this embodiment as well, the arrangement is such that l/C11LI is an integral multiple of the dot pitch and an integral multiple of the printing object feed pitch.

A schematic cross-sectional view of a bubble jet head having an L-shaped liquid flow path is shown in FIG. In the figures, like parts in the apparatus shown in FIGS. 1-9 are designated by the same reference numerals.

In this device, droplets are ejected using the pressure generated by the foaming, but since the opposite direction of the ejection direction is the wall surface that has an electrical X-thermal converter, most of the energy of the pressure waves is Because the water propagates in the discharge direction, the discharge energy can be used with high efficiency, and this can also be used to deal with untimely discharge and thickening. It is also an effective device.

The droplet ejection device of the present invention is arranged so that each of the ejection ports faces the surface on which the electrothermal converter is provided, and arranged perpendicularly to the scanning direction of the broken egg photographic object. By arranging the droplet ejection heads adjacent to each other so that the distance between the opposing ejection openings is an integral multiple of the dot pitch and an integral multiple of the printing object feed pitch, the apparatus can be made smaller and more compact. The ejection timing can be easily controlled, improving mass productivity and making it easier to assemble printers and the like.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of a conventional droplet ejection head, Fig. 2 is a schematic diagram of a conventional droplet ejection device, Fig. 6 is a view of the conventional droplet ejection device looking at the ejection port side, and Fig. 4 is a schematic diagram of a conventional droplet ejection head. The figure is a schematic cross-sectional view of a droplet ejection head in which each of the ejection ports faces the surface on which an electrothermal converter is provided, and FIG. 5 is shown in FIG. 4. 6 is a schematic diagram of the droplet discharge device of the present invention, FIG. 7 is a diagram of the droplet discharge device of the present invention viewed from the discharge port side, and FIG. 8 is a combination of four droplet discharge heads. FIG. 9 is a schematic diagram of the droplet discharge device of the present invention, as seen from the discharge port side of the droplet discharge device shown in FIG.
FIG. 10 is a schematic cross-sectional view of a bubble jet head having an L-shaped liquid flow path. 1.1'...Droplet discharge head 2...Droplet 3...Liquid flow path 4...Electrothermal converter 5... -Liquid chamber 6...Platen 7...Imprinted object 8...Liquid supply pipe 9...Discharge port H...Head Scan space l, f, lll, llll... Distance between opposing ejection port rows of mutually adjacent droplet ejection heads No. 31!1'l No. 7 Diagram No. 10

Claims (1)

[Claims] A plurality of ejection ports are provided for ejecting liquid to form flying droplets by using thermal energy, and the liquid for forming the flying droplets is supplied by communicating with these ejection ports. and a plurality of electrothermal converters serving as means for generating the thermal energy, provided corresponding to each of the discharge ports, and each of the discharge ports In a droplet discharging device having two or more droplet discharging heads facing the surface on which the droplet discharging device is provided, the droplet discharging device having a width larger than the width of the object to be printed is placed in the object scanning direction. When arranged perpendicular to , the distance between opposing ejection port rows of adjacent droplet ejection heads is - an integral multiple of the dot pitch and an integral number of the printing object feed pitch.
Alternatively, a droplet ejecting device characterized in that the droplets are arranged in an integral multiple.