JPH03197146A - recording head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a recording head used for, for example, image processors, electronic typewriters, facsimile machines, and various bulletin boards.

[Conventional technology]

Nowadays, thermal recording is the mainstream recording method for information processing. This recording method uses an ink film formed by coating a support with heat-melting ink, heats the ink film in an image pattern with a recording head, and transfers the molten ink to recording paper. . According to this method, the apparatus used can be made smaller and lighter, and recording can be performed on plain paper. However, the thermal transfer recording method described above has drawbacks such as high running costs and complicated processing of used ink films because the ink film once used must be discarded. Therefore, in order to improve these drawbacks, the applicant of the present application has proposed that a housing 2 capable of storing ink 3 is attached to one surface of the substrate 4, as shown in FIGS. 4(A) and 4(B). A heating element 7 is provided in which each unit selectively generates heat according to an image signal, and each unit of the heating element 7 has a through hole (ink passage hole) 8 through which one or more ink passes. On the heating element 7 is an ink reservoir 1 divided into a plurality of parts by a spacer 9 called a window.
3 was proposed. [Problems to be Solved by the Invention] When this recording head is used, the ink reservoir 13 portion of the recording head is brought into contact with the recording medium, and while the two are moved relative to each other, the heating element 7 is activated in accordance with the image signal. When you generate heat,
The ink in the ink reservoir 13 has a low viscosity and is transferred onto the recording medium, and immediately after that, the ink in the housing 2 passes through the ink passage hole and is transferred only to the portion of the recording medium that faces the inside of the ink reservoir 13. This is what ink is transferred to. According to the above method, since there is no need to use an ink film, running costs can be reduced, and since the ink can be directly heated without using a film, there are advantages such as good thermal energy efficiency. However, in the above method, the spacer 9 that divides the recording dots and the recording paper 1o, which is the recording medium, are in direct contact with each other and the recording paper 1o is moved in this state, so that there is no ink between adjacent bits to be recorded (i.e., portions facing each spacer 9), resulting in a decrease in image quality. SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides a recording head that does not use an ink film and is less likely to cause ink-free areas between adjacent dots. [Means for Solving the Problems] The present invention, which solves the above conventional problems, includes a substrate, a housing provided on one surface of the substrate and capable of accommodating ink, and a housing placed on the other surface of the substrate. a heating element that is embedded in or embedded in the substrate, each unit of which selectively generates heat according to an image signal, and a heating element and a recording medium that are provided on at least one of the heating element and the substrate. The recording head is equipped with a plurality of spacers that keep the medium out of contact with the medium, and is provided with an ink passage hole that passes through the heating element and the substrate or through the heating element corresponding to each unit of the heating element. The recording head is characterized in that at least a part of the downstream region of the heating element, where ink emitted from the passage hole spreads, is not separated by spacers. [Example J] The present invention will now be described by way of examples. FIG. 1 is a schematic sectional view of a recording device, and FIG. 2 is an external view of a multi-type recording head in which the recording sections of the recording head are arrayed in a line. , so-called heat-melting (including softening and sublimation) ink 3 that maintains high viscosity at room temperature but decreases in viscosity at high temperatures is housed inside the housing 2. A ceramic substrate 4 made of alumina, zirconia, etc. is provided, and one surface of the substrate 4 has a
A reinforcing plate 5 made of a stainless steel plate, an iron plate, a copper plate, or the like is provided. A gold electrode 6 and a heating element 7 made of ruthenium oxide are provided on the other surface of the substrate 4. This heating element 7
As shown in the figure, a plurality of heating elements 7 are arranged in an array at a pitch of 1 mm, and each heating element 7 is provided with an ink passage hole 8 having a width of 0.3 mm. In addition, each heating element 7 (each heating element unit) selectively applies a voltage to the gold electrode 6 according to the image signal.
It is configured to generate heat individually by applying Furthermore, the substrate 4 is provided with a spacer 9 made of glass.
is provided. This spacer is 25μ thick. Recording by the recording head is carried out by bringing a spacer 9 into contact with a recording paper 1°, which is a recording medium, as shown in FIG. This is done by forming a predetermined image 12. These recording methods will be explained in more detail below. First, when a voltage pulse corresponding to an image signal is applied to the heating element 7 through the electrode 6, the heating element 7 selectively generates heat, and the ink 3 near the heating element 7 is heated. The ink has a high viscosity at room temperature and therefore does not pass through the ink passage hole 8, but when heated as described above, the viscosity decreases and it passes through the ink passage hole 8. The ink 3 that has passed through the ink passage hole 8 in this way is transferred to the heating element 7.
and the recording paper lO. At this time, this recording paper 10
While being conveyed by the platen roller 11 rotating in the direction of arrow a, at the same time, the ink 3 is transferred to record a predetermined image. Note that it is preferable to apply a static pressure of about 0.1 atm (gauge pressure), which is higher than the outside air pressure, inside the housing 2 because passage of the ink 3 through the ink passage holes 8 is promoted. By repeating the above steps according to the image signal, recording dots are continuously formed on the recording paper and the ink image is transferred. FIGS. 3(a) to 3(e) show external views of the recording section of the recording head. A common electrode 6a and a signal electrode 6b are provided on the substrate 4 in FIGS. 3(a) and 3(b). In the figure, arrow a indicates the direction in which the recording paper is conveyed.The heating element 7 and the recording paper are kept out of contact with each other by a spacer 9. In FIGS. 3(a) and 3(b), the spacer 9 is
Focusing on the flow direction of ink to the recording paper, it is provided upstream of the heating element 7. Due to the heat generated by the heating element 7, the ink passes through the ink passage hole 8, which may have a single hole or multiple holes, and spreads between the heating element 7 and the recording paper and is recorded as a dot on the downstream side of the heating element 7. Since there is no separation by the spacer 9, the ink contacts and overlaps between the dot and the adjacent dot recorded in the same way, so there is no ink-free area between the adjacent dots, and a clear image is obtained. be able to. As shown in FIG. 3(b), when there are two ink passage holes 8 corresponding to each dot, the ink spreads smoothly toward the adjacent dots, making it possible to obtain even better images. I can do it. Third
In Figure (C), the spacer 9 is located upstream of the heating element 7 and is provided directly on the substrate 4. In this case, as shown in FIGS. 3(a) and 3(b), since there is no spacer 9 on the heating element 7, the ink spreads across the gap between the heating element 7 and the recording paper, and the ink of adjacent dots overlaps with each other. Since the dots overlap each other, there will be no ink-free areas between adjacent dots, and high-quality images can be recorded. Furthermore, by providing spacers 9 for every two or more dots as shown in FIG.
If it is not separated by , the effects described above will occur. In the case of FIG. 3(e), immediately after recording, the dots do not necessarily overlap with the adjacent dots, but the dots are located downstream of the heating element 7 and constantly generate heat, or Since the heating element 7a is provided which generates heat with a delay in heating time by the amount of ink movement from the body to the heating element, the ink once hardened is transferred to the spacer 9.
It melts and spreads again in areas not bounded by. Therefore, adjacent dots overlap, and a clear image can be obtained as described above. Note that as a means for causing the ink to spread and come into contact with each other on the downstream side of one heating element, not only a heating means as described above but also a pressurizing means or the like can be used. Next, the ink to be filled into the recording head will be explained. As this ink, typically a thermofusible ink can be used. The ink is made by dispersing or dissolving a coloring agent in a heat-melting binder, and elastomers and the like are added to the heat-melting binder to adjust the melt viscosity, adhesive strength, etc. Heat-melting binders include various conventional binders such as natural or synthetic wax resins, which can be used alone.
Or a mixture of two or more types can be used. As the coloring agent constituting the heat-melting ink together with the heat-melting binder, any dye or pigment commonly used in printing or other recording methods, such as carbon black, may be used alone or in a mixture of two or more. The content of the colorant contained in the above ink is preferably 1 to 40% by weight. In the above embodiment, ruthenium oxide was used as the heating element, but the material is not limited to this material as long as it can generate heat when energized; for example, ceramics such as tantalum nitride, nickel chromium oxide, etc. It may be constructed by being provided on a heat-resistant plate such as a metal such as aluminum coated with heat-resistant insulation with polyimide or the like. Further, the electrodes may also be made of aluminum, copper, nickel chromium, etc. or various alloys in addition to the gold used in the above embodiments. The size of the voltage pulse applied to the heating element, the number of ink passage holes, and even the pressure applied to the ink are not particularly limited, and the type of ink used, the depth of the ink passage holes, the thickness of the spacer, etc. It may be changed as appropriate. Although paper was used as the recording medium in the above embodiments, it is also possible to use paper with a surface made of fluorine resin or silicon resin, which has a relatively poor wettability and is used for so-called whiteboards, electronic blackboard sheets, etc. It can be used even if it is [Effects of the Invention] As described above, in the present invention, first, the ink in the housing is selectively heated by the heating element to reduce the viscosity of the ink and transfer it onto the recording medium, instead of using an ink film as in the conventional method. Moreover, since at least a part of the area where the ink spreads on the downstream side of the heating element is not separated by a spacer, it is possible to record a clear image without leaving any areas with no ink between adjacent dots. .

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of the present invention, FIG. 2 is an external view of a multi-type recording head in which recording parts of the recording head are arrayed in a line, and FIGS. 3(a) to (e) FIG. 4(a) is an external view of the recording section of the recording head. (b) is an explanatory diagram of the prior art. 1: Recording head 2: Housing 3: Ink 4: Substrate 6 electrode near: Heating element
8: Ink passage hole 9 Varnish spacer - lO: Recording paper 1 Platen roller

Claims (1)

[Claims] 1) A substrate, a housing provided on one surface of the substrate and capable of accommodating ink, and an image provided on the other surface of the substrate or embedded in the substrate. Equipped with a heating element that selectively generates heat in each unit according to a signal, and a plurality of spacers provided on at least one of the heating element and the substrate to keep the heating element and the recording medium out of contact. In a recording head in which an ink passage hole passing through the heating element and the substrate or through the heating element is provided corresponding to each unit of the heating element, an area on the downstream side of the heating element where ink emitted from the ink passage hole spreads. A recording head characterized in that at least a portion of the recording head is not separated by each spacer.