JPS5948146B2 - Coating device with blade type applicator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an applicator that utilizes a blade applicator for dispensing fluid materials.

The internal geometry of the blade applicator is designed to efficiently control the flow rate and distribution of the application material as it is transferred to the supporting substrate. The apparatus is particularly suitable for use in depositing uniform coatings at regular intervals on a continuous substrate. Techniques for applying uniform thin films of fluid compositions are known in the art.

For example, in printing technology, in order to distribute ink from an ink reservoir onto a printing plate, such ink is distributed from an applicator to a series of intermediate rollers, and these intermediate rollers deposit a predetermined amount of ink on the printing plate. ．． is usually required. The printing plate is then brought into contact with an image bearing sheet, and the image information is transferred to the image bearing sheet. A series of rollers between the ink applicator and the printing plate can usually be adjusted to adjust the amount of ink that is ultimately deposited on the printing plate. To adjust the amount of ink introduced into this,
This can also be achieved by adjusting the amount dispensed by the applicator to the intermediate roller. For example, U.S. Pat. No. 3,766,856, U.S. Pat. No. 3,739,721
No. 3,363,530. These patents are not exhaustive and are merely illustrative of representative applicator devices. If an intermediate transfer means is used between the ink applicator and the printing plate in the above-described manner, the steps required when distributing the ink from the applicator to the intermediate roller. There is no need to pay much attention to the amount of ink or the shape of its distribution. This is because the intermediate roller is designed to smooth out changes in the physical properties of the ink adhering to the intermediate roller before applying the ink to the plate surface. If such an intermediate roller is removed, . If the ink were to be dispensed directly from the applicator to the printing plate, uniformity of supply and quantity of ink exiting the applicator would be extremely important. This is especially true if the consumption of ink by the ink storage member is periodically interrupted. When such interruptions occur, the ink distribution pattern formed by the applicator blade typically follows a non-uniform distribution pattern, reflecting changes in the amount of ink distributed at different points along the applicator. create a relationship. When applying fluid materials to various supporting substrates,
I come across a similar problem. Typically, excess material is supplied to the application site and the amount dispensed onto the image bearing sheet is regulated by a doctor blade device. An asymmetrical trailing edge of the coating material results when the coating operation is interrupted, either because the reservoir containing the coating material empties, or because the image support surface is displaced beyond the coating area. It is therefore an object of the present invention to provide a blade applicator device which substantially does not have the above-mentioned disadvantages of such prior art devices.

More particularly, a primary object of the present invention is to provide a blade applicator device that can uniformly and intermittently apply a fluid composition to a continuous substrate. Another object of the invention is to provide a blade applicator device suitable for applying photoelectrophoretic inks without altering the uniformity of the dispersion of particles in such inks. Another object of the invention is to provide an apparatus for using the blade applicator apparatus described above in combination with other components, in particular a photoelectrophoretic imaging apparatus.

These and other objects of the invention are achieved by a blade applicator device having a slotted cavity running parallel to the edge of the blade.

The ceiling part of this grooved cavity is defined by the inner wall of the upper part of the applicator device, and the floor part of this cavity is defined by the inner wall of the lower part of the applicator device. One of said parts of the applicator device is provided with at least one port and at least a pair of application material distribution passages extending radially from said inlet at an inclined angle towards the open end of the cavity. It is being The angle of inclination of the pair of passageways and their associated diameters substantially uniformly distribute the application material along the edge of the blade applicator device. The lower portion of the applicator device, which is provided with a blade edge, is further adapted to apply a uniform thin film thickness of the coating material to the image bearing surface. A blade applicator device of the above design is well suited for both continuous application of a coating as well as intermittent application of a coating to a continuous substrate. The blade applicator device of the present invention consists of one or more component parts, depending on the materials used in its construction and the manufacturing method. FIG. 1a shows a top perspective view of an exemplary embodiment of the blade applicator device 2 of the present invention.

Since the application material dispensing part 4 of this applicator device occupies the uppermost part of the structure, the lower part 6 of this applicator device (hereinafter referred to as "application material application part") except for its leading edge 8 It's almost hidden and invisible. The material dispensing part of this applicator device consists of a central feed distribution plate 1 which has two lateral channels 12a, 12b extending radially from the inlet 13 towards the open end blind 4 of the grooved cavity blind 6.
Consists of 0. In order to evenly distribute the application material between these radial passages, the inlet 13 of the distribution plate 10 must be located at right angles to the open end 14 of the grooved cavity 16. The inlet 13 is also preferably inclined with respect to the wide (horizontal) plane of the grooved cavity. This grooved cavity is constituted by the space between the inner wall 17 of the application material distribution part of the applicator device and the inner wall 18 of the material application part of the applicator device. Fluid application material (not shown) is pressurized from a supply reservoir (not shown) into the blade applicator device through the centrally located inlet 13 of the distribution plate 10, and the fluid As shown, it is uniformly distributed within the grooved cavity 16 and thus flows from the inlet through these passages out the open end of the grooved cavity, at which point the application material distribution section of the blade applicator device is disposed of. is uniformly applied to the image-bearing substrate by the leading edge of the image-bearing substrate.

The inlet of the material dispensing portion of the blade applicator device is referred to as being "centrally located" to indicate its location with respect to the path that directs fluid from the inlet toward the open end of the grooved cavity. Not too much. Accordingly, in the embodiment of the invention shown in FIG. 1b, the distribution plate has two independent inlets, each having one inlet located "in the middle", which is separately supplied with the application material. It is equipped with a unit that functions as Additionally, as will become clearer from the discussion of FIG. 3, the internal geometry of the grooved cavity does not require that the passages in the application material distribution portion of the applicator device be of equal length. The only important requirements for the design of this grooved cavity are that the angle of inclination of each passage with respect to the inlet be the same, and that this angle of inclination be determined to correspond to the description in Figure 3. . Therefore, as in the embodiment of the invention shown in FIG. 1c,
Blade applicator devices are also possible (and under certain conditions preferred) in which the passageways of the application material distribution sections are of different lengths and therefore the location of the inlet must be moved from the center. Figures 2a and 2b show cross-sectional views of the blade applicator device in planes a-a and b--b, respectively. The rear interior wall of the grooved cavity, opposite the open end of the grooved cavity, runs flush with a radially angular passageway from the centrally located inlet. As is clear from FIG. 2, the rear inner wall of the grooved cavity is constituted by a portion of the coating material distribution plate. However, the inner wall can also be formed by a part of the material application part of the applicator device or by a separate shim of suitable thickness. FIG. 2c shows a vertical cross-sectional view of another embodiment of the blade applicator device of the present invention, similar in construction to that previously illustrated and described. .

The grooved cavity is constituted by the space between the inner wall 17a of the upper component and the inner wall 18a of the bottom component of the applicator device, as in FIG. 2b. The application material is distributed through the inlet 1 located at the bottom of the applicator device.
This is achieved by introducing the coating material through 3a. These coating materials are pumped through passageways 25a and 25b (not shown) and cavity 16a and are discharged from the cavity orifice in a uniform stream of coating material. FIG. 3 is a schematic diagram illustrating the dimensional relationships of the various passageways of the application material distribution section of the blade applicator device. In order to achieve a uniform flow of the application material from the open end of the grooved cavity, the application material of the applicator device must be adjusted so that the ink traveling through the cavity encounters the same flow resistance at every point in the cavity. It is necessary to balance the design of the various passages in the distribution section. The objective of such a design is therefore to make the pressure drop of a-+b the same as that of a→c, and the pressure drop of b-+b'' to be the same as that of c+c''.

These objectives can be achieved by an applicator device in which the various dimensional relationships of the internal passages of the blade applicator device are expressed by the equations below. 1 The inclination angle of the passage extending radially from the inlet can be expressed as:

In the formula, R is the fluid pressure radius (Ft) of the inclined passage, q is the fluid flow rate per unit length (Ft2/Sec), VO is the fluid velocity in the inclined passage (Ft/Sec), and H is the grooved cavity. is the vertical distance (Ft) between the floor and ceiling portions of .

The ink pressure at the inlet of the two inclined passages can be expressed as:

where Q, O and H are the same as defined above and 1μ is the viscosity of the fluid introduced through the inlet (1bs-Sec/Ft2
), w is the specific gravity of the fluid (1bs/Ft3), L is the distance from the top of the grooved cavity to the mouth of the grooved cavity (Ft), 2β is the gravitational pressure (1b
s/Ft2), and g is the power constant (Ft/Sec2).

Under optimal operating conditions, the amount of fluid dispensed by the blade applicator device is equal to the amount delivered. Assuming that the applicator device is manufactured to the design requirements shown in the equation above, when the fluid flow is interrupted at the end of the fluid flow delivery, the fluid will be applied over the entire leading edge of the blade. Stop uniformly along the line. As the value of α and the hydraulic radius (R) of the radial passages vary, so do the other internal dimensions of the grooved cavity.

In a preferred working example of the invention, α is about 10° and the hydraulic radius (R) of the angled passage is about 35°.
mi1), and the width (H) of the grooved cavity is approximately 0.0127 to 0.0508 cm (5 to 20 mi).
There are 3 within the range of . Approximately 10.16 to 12.7 cm (
Introducing the coating fluid at a rate within the range of 4 to 51 n/Sec) results in a coating device compatible with the objectives of the present invention. FIG. 4 shows an example of a practical application of blade applicator devices 2 to 4 applying material 20 to a repeatable member 22. FIG.

The angle of inclination of the trailing edge 24 of the application material application portion of the applicator device is preferably 45° or less, so that when the applicator device and the receiving surface are separated from each other by their relative movement. The fluid bulge (meniscus) 26 becomes smaller. As previously highlighted, the blade applicator device of the present invention is unique because it allows for uniform application of fluid despite periodic interruptions in the supply of application material.

This blade applicator device is therefore particularly suitable for use in conjunction with a fluid supply means, such as a perturbation pump, which is capable of intermittent interruption of the flow of application material. Variations contemplated within the scope of the invention of the embodiments of the invention specifically shown and described above include moving the inlet from the position of FIGS. 2a and 2c to a component of the applicator device facing the inclined passageway. Including moving. With this movement, the material distribution pattern is essentially the same (Figure 3), and all other previously mentioned requirements regarding the orientation of the inlet relative to other components of the applicator device also apply.

[Brief explanation of the drawing]

FIG. 1a is a top perspective view of a blade applicator device according to the invention; FIG. 1b is a top perspective view of a blade applicator device having multiple dispensing chambers; FIG.
Figure 2a is a top perspective view of a blade applicator device with an off-center inlet and varying lengths of slanted passages extending radially from the inlet; Figure 2b is an enlarged vertical cross-sectional view of the blade applicator device taken along lines 2a-2a of Figure 1, Figure 2c; FIG. 3 is an enlarged vertical cross-sectional view of another embodiment of the blade applicator device of the present invention in the plane where the inlet and the inclined passage meet; FIG.
FIG. 4 is an enlarged cross-sectional view showing the relationship between the image-bearing sheet and the blade applicator device; FIG. It is. 2...Blade type applicator device, 4...
... Application material distribution part, 6 ... Application material application part, blinds 2a, 12b ... Radial passage, 13,
13a... Entrance, 16, 16a... Grooved cavity, 17, 17a... Inner wall of coating material distribution part, 18, 18a... Coating material application. Inner wall of portion, 25a, 25b... radial passage,
α...Inclination angle of radial passage, R...
Hydraulic radius of the radial passage.

Claims (1)

[Scope of Claims] 1. A coating device comprising a reservoir for coating material, a blade-type applicator device, and means for supplying coating material from the reservoir for coating material to the blade-type applicator device, comprising: the type applicator device has a grooved cavity running parallel to the edge of the blade, the ceiling portion of the cavity being defined by the inner wall of the upper portion of the applicator device; A floor portion of the cavity is constituted by an inner wall of a lower portion of the applicator device, and one of the portions of the applicator device has at least one inlet and an angle of inclination from the inlet toward the open end of the cavity. at least one pair of radially extending application material distribution passages, the angle of inclination of said passages and their associated diameters distributing application material substantially uniformly along an edge of said blade. and a lower portion of the applicator device is adapted to apply a uniform thin film thickness of coating material to the image bearing surface. 2. Applicator device according to claim 1, characterized in that the upper part of the applicator device is provided with an inlet and a pair of distribution passages extending radially from the inlet. 3. Applicator device according to claim 1, characterized in that the lower part of the applicator device is provided with an inlet and a pair of distribution passages extending radially from the inlet. 4. Applicator device according to claim 1, characterized in that the applicator device is provided with an inlet in its upper part and a pair of distribution passages extending radially from the inlet in its lower part. 5. Applicator device according to claim 1, characterized in that the lower part of the applicator device is provided with an inlet and the upper part is provided with a pair of distribution passages extending radially from the inlet. 6. Applicator according to claim 1, wherein the inlet is perpendicular to the open end of the cavity. 7. The coating device according to claim 1, wherein the inclined passages extending radially from the inlet have different lengths. 8. The coating device of claim 1, wherein the angle of inclination of each passage with respect to the inlet is substantially the same. 9. The coating device according to claim 1, wherein the inlet is at an angle of inclination with respect to the wide plane of the cavity. 10. The applicator device of claim 1, wherein the internal geometry of the passageway and cavity of the applicator device is such that it provides the same flow resistance to the application material at all points throughout the cavity.