JP2008048924A - Tablet coating apparatus and tablet coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating apparatus and method which enable the continuous and moreover contactless implementation of a tablet coating treatment. <P>SOLUTION: The tablet coating apparatus 1 is provided with a belt conveyor 11 for continuously conveying tablets 16 in one direction. A nozzle head 10 with a jet nozzle 41 using a piezoelement is provided nearly at the central part of the belt conveyor 11. The nozzle head 10 has the same structure as that of the printer head of the ink jet printer to make microscopic liquid drops of a coating base material spray through it. The microscopic liquid drops of the coating base material are sprayed onto the tablets on the belt conveyor 11 from the nozzle head 10 to form a skin film of the coating base material on the surface of each tablet 16. The tablets 16 undergo a contactless and continuous coating treatment being conveyed with the belt conveyor 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tablet coating apparatus and method used for pharmaceuticals, foods, health foods, and the like, and more particularly to a coating processing technique for forming a coating layer on a tablet surface by a jet nozzle using a piezoelectric element.

In pharmaceuticals and foods, masking the bitterness and smell of drugs and foods, protecting internal chemicals from moisture and oxygen in the atmosphere, and effectively preventing degradation and degradation A coating process for forming a film such as a sugar coating liquid on the surface is widely performed. Conventionally, such a coating process is generally performed by a drum type (pan type) coating apparatus using a rotating drum. For example, Patent Document 1 describes an apparatus including a rotating drum called a coating pan having a polygonal cross section (here, an octagon). The rotating drum rotates around a horizontal axis, and a spray device is installed in the rotating drum. The granular material thrown into the rotating drum rolls along with the rotation of the drum, and the coating liquid is sprayed on the surface from the spray device. At that time, hot air or cold air is appropriately supplied / exhausted from the air supply / exhaust duct into the rotating drum, whereby the coating substrate is evaporated and dried on the surface of the object to be processed, and a coating layer is formed.
JP-A-6-63376 JP-A-61-57267 JP 2005-531330 gazette Special Table 2000-512303 JP 2006-89741 A

  However, such a conventional coating processing method is a so-called batch type process in which a predetermined amount of processing object is put into the rotating drum and the next processing object is not put in until the coating processing is completed. There was a problem that there was a limit to the amount of processing. On the other hand, for example, as in Patent Document 2, the coating process can be continuously performed by impregnating the porous material having elasticity with the coating liquid and passing the object to be processed while sequentially pressing the object. Such devices have also been proposed. However, such a method has a problem that it is difficult to maintain the aesthetic appearance of the coating surface and prevent wear because of the contact-type coating process in which the porous body is pressed against the workpiece. In addition, since it is necessary to set various conditions such as the pressure contact condition, the processing speed, the material of the porous body and the impregnation state of the coating liquid, it is actually not practically used.

  An object of the present invention is to provide a coating apparatus and method capable of continuously and non-contactly coating tablets.

  The tablet coating apparatus of the present invention is a tablet coating apparatus for forming a coating substrate film on the surface of a tablet, the tablet transporting means capable of continuously transporting tablets in one direction, and the tablet transporting means in proximity to the tablet transporting means. And a nozzle device that ejects minute droplets of the coating substrate onto the tablet by the operation of a piezo element.

  In the present invention, the tablet transporting means is provided, and the tablet coating process is performed by the nozzle device using the piezoelectric element while transporting the tablet by the tablet transporting means. A coating process can be performed. For this reason, a continuous coating process is attained, improving the aesthetics of a tablet and preventing abrasion. In addition, the tablet coating apparatus of the present invention is a non-contact process, so that it can be applied to tablets with high friability, soft tablets with low hardness, tablets that are easily disintegrated, etc. Can be applied.

  In the tablet coating apparatus, droplets of the coating base material may be ejected by the nozzle device at an ejection density of 400 to 700 dpi. In this way, by making the droplets of the nozzle device slightly larger than the droplets of the ink jet printer used for photo printing and printing, a film layer with a uniform film thickness can be formed on the entire surface of the tablet, improving the coating quality Is planned. In addition, the coating substrate includes polyethylene glycols, polyoxyethylene, polyoxypropylene glycols, rosin, hydrogenated rosin glycerin ester, ester gum, vinyl acetate resin, carnauba wax, beeswax, white beeswax, hydrogenated oil, paraffin Further, it may contain a substance selected from the group consisting of waxes such as stearic acid and stearyl alcohol.

  On the other hand, the tablet coating method of the present invention is characterized in that a fine droplet of the coating substrate is ejected onto the tablet by a nozzle device using a piezo element to form a film of the coating substrate on the tablet surface. And

  In the present invention, since the tablet coating process is performed by a nozzle device using a piezo element, a film can be formed on the tablet surface in a non-contact state, while improving the aesthetics of the tablet and preventing abrasion, A film coating layer can be formed on the tablet surface. In addition, the tablet coating apparatus of the present invention is a non-contact process, so that it can be applied to tablets with high friability, soft tablets with low hardness, tablets that are easily disintegrated, etc. Is possible.

  In the tablet coating method, droplets of the coating base material may be sprayed onto the tablet at a spray density of 400 to 700 dpi by the nozzle device. In this way, by making the droplets of the nozzle device slightly larger than the droplets of the ink jet printer used for photo printing and printing, a film layer with a uniform film thickness can be formed on the entire surface of the tablet, improving the coating quality Is planned. In addition, the coating substrate includes polyethylene glycols, polyoxyethylene, polyoxypropylene glycols, rosin, hydrogenated rosin glycerin ester, ester gum and vinyl acetate resin, carnauba wax, beeswax, white beeswax, hydrogenated oil, paraffin Further, it may contain a substance selected from the group consisting of waxes such as stearic acid and stearyl alcohol.

  According to the tablet coating apparatus of the present invention, in the tablet coating apparatus for forming the coating base film on the tablet surface, the tablet transporting means capable of continuously transporting the tablets in one direction is provided. In close proximity, a nozzle device that ejects minute droplets of the coating substrate onto the tablet is arranged by the operation of the piezo element, so a coating substrate film can be formed on the tablet surface in a non-contact state. It is possible to form a film coating layer on the tablet surface while improving the aesthetics of the tablet and preventing wear. In addition, the tablet coating apparatus of the present invention is a non-contact process, so that it can be applied to tablets with high friability, soft tablets with low hardness, tablets that are easily disintegrated, etc. It is possible to increase the number of objects to be coated.

  According to the tablet coating method of the present invention, a fine droplet of the coating base material is sprayed onto the tablet by a nozzle device using a piezo element so that a film of the coating base material is formed on the tablet surface. A coating substrate film can be formed on the tablet surface in a non-contact state, and a film coating layer can be formed on the tablet surface while improving the aesthetics of the tablet and preventing abrasion. In addition, the tablet coating apparatus of the present invention is a non-contact process, so that it can be applied to tablets with high friability, soft tablets with low hardness, tablets that are easily disintegrated, etc. It is possible to increase the number of objects to be coated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing a system configuration of a tablet coating apparatus according to an embodiment of the present invention. As shown in FIG. 1, the tablet coating apparatus 1 (hereinafter abbreviated as the coating apparatus 1) is roughly composed of a coating processing unit 2, a coating liquid supply unit 3, and a control unit 4. In the coating apparatus 1 according to the present invention, a nozzle head 10 using a piezoelectric element (piezoelectric element) is installed in the coating processing unit 2. A coating substrate is supplied from the coating liquid supply unit 3 to the nozzle head 10 under the control of the control unit 4. In the coating processing unit 2, a coating base material is sprayed onto the tablet by the nozzle head 10, and a coating layer is formed in a non-contact manner on the tablet surface.

  The coating processing unit 2 is provided with tablet conveying means using a belt conveyor 11. The belt conveyor 11 includes a driving pulley 12 that is driven by a motor (not shown), a driven pulley 13 that is rotatably arranged, and a conveyor belt 14 that is stretched between the driving pulley 12 and the driven pulley 13. ing. A tablet supply unit 15 is provided on the upstream side of the conveyance belt 14, and a tablet 16 as an object to be processed is placed on the conveyance belt 14 there. On the other hand, a tablet discharge unit 17 is provided on the downstream side of the transport belt 14, and the coated tablet 16 is lowered from the transport belt 14 there.

  The coating processing unit 2 is further provided with a nozzle head 10. The nozzle head 10 is disposed at an intermediate position between the tablet supply unit 15 and the tablet discharge unit 17, and the tablet 16 is subjected to a coating process here. The nozzle head 10 is connected to the coating liquid supply unit 3 via a hot hose 21 and to the control unit 4 via a control line 22. As shown in FIG. 1, the coating liquid supply unit 3 is provided with a heating tank 24 in which a coating base material 23 is stored. A heater 25 is attached to the heating tank 24, and the temperature in the heating tank 24 is controlled by the control unit 4. A pump 26 is also disposed in the coating liquid supply unit 3, and the coating base material 23 is supplied from the heating tank 24 to the nozzle head 10 under the control of the control unit 4.

  The control unit 4 includes an interface unit 31 to which the control line 22, the heater 25, and the pump 26 are connected, a CPU (central processing unit) 33 and an input / output unit 34 connected to the interface unit 31 via the bus line 32. Is provided. The input / output unit 34 is provided with an input unit (ten key, input button, switch, etc.) 34a for inputting processing conditions and the like, and a monitor 34b for displaying the processing status. The control unit 4 further includes a ROM 35 and a RAM 36, and the ROM 35 stores a control program for performing the coating process. In addition, the RAM 36 stores the processing conditions input by the input unit, the current processing status, and the like.

  Here, as described above, the jet nozzle (nozzle device) 41 using a piezoelectric element is used for the nozzle head 10 of the coating apparatus 1. FIG. 2 is an explanatory diagram showing the configuration of the jet nozzle 41. In the coating apparatus 1, a large number (about 30 to 100) of jet nozzles 41 as shown in FIG. 2 are arranged to form the nozzle head 10. . The nozzle head 10 is the same as the printer head of an ink jet printer, but unlike the ink jet printer, the nozzle head 10 itself is fixed to an apparatus main body (not shown) without moving.

  As shown in FIG. 2, the jet nozzle 41 is provided with a pressure chamber 43 surrounded by partition walls 42a and 42b. A piezo element 44 is disposed on the outer surface of the partition wall 42a, and a nozzle hole 45 is formed through the partition wall 42b. The piezo element 44 is an electro-mechanical conversion element, is connected to the control unit 4 via the control line 22, and is mechanically deformed by an electric signal input from the control unit 4. The nozzle holes 45 are minute holes of about 50 μm, and about 1 to 10 nozzle holes 45 are provided for each jet nozzle 41, and about 400 to 600 nozzle holes 45 are arranged in one nozzle head 10. . A high frequency voltage of about 10 kHz is supplied to the piezo element 44, whereby vibration is applied from the piezo element 44 to the pressure chamber 43, and a droplet is ejected from the nozzle hole 45. The size and ejection frequency of the droplets can be appropriately controlled by the applied voltage frequency and voltage value.

  In the inkjet printer, there are two types of deformation directions of the piezo element 44: a “longitudinal vibration type” that vibrates in the longitudinal direction in FIG. 2 and a “flexible type” that vibrates in the thickness direction. In general, in the case of photographic printing and printing, since high resolution and high density are required for photographs and the like, a “longitudinal vibration type” that can take a large amount of deformation is often employed (particularly, a high-end model). On the other hand, in tablet coating, there is less demand for miniaturization / high density of jetted droplets compared to photographs, etc., and in terms of forming a coating layer having a uniform film thickness on the entire tablet surface, It is advantageous that the ejection density (synonymous with the resolution of an inkjet printer) is not too high. In this case, if the jet nozzle 41 having a high spray density is used, the film thickness may be uneven, and a nozzle having a high spray density (high resolution) acts disadvantageously from the viewpoint of coating.

  On the other hand, Patent Documents 3 to 5 show a configuration in which ink jet printing is performed on medicines, foods, and the like. However, claims 2 and the like point out that the resolution is high. This is because the printing process for identifying characters and the like is different from the coating process in that the print site is specified and high resolution is required for character discrimination. In this respect, the coating process for forming a film layer (film) with a uniform film thickness on the entire surface of the tablet does not require a positioning process or the like, and does not require high resolution. For this reason, in the coating apparatus 1, the “flexible type” is adopted as the deformation direction of the piezo element 44 with priority given to mass productivity over resolution, and the coating apparatus 1 can be configured with inexpensive parts. It is also possible to employ a jet nozzle having a lower injection density (for example, about 100 to 300 dpi).

  Such a jet nozzle 41 ejects coating droplets from the nozzle hole 45 as follows. FIG. 3 is an explanatory diagram showing the operation of the jet nozzle 41 in that case. When a voltage is applied to the piezo element 44 from the control unit 4, the piezo element 44 bends in an arc shape as shown in FIG. The partition wall 42 a is elastically formed so as to be operable with the piezo element 44, and the partition wall 42 a is similarly deformed in an arc shape with the deformation of the piezo element 44. Thereby, the coating base material 23 in the pressure chamber 43 is drawn into the indoor side as shown in FIG.

  After drawing the coating base material 23 into the room, the voltage application to the piezo element 44 is stopped. When the voltage application is stopped, the piezo element 44 suddenly returns to its original shape, and accordingly, the partition wall 42a operates similarly. That is, as shown in FIG. 3A, the partition wall 42a bent in a convex shape rapidly returns to a flat plate shape as shown in FIG. 3B. For this reason, the coating base material 23 once drawn into the pressure chamber 43 is pushed downward by the operation of the partition wall 42 a, whereby the coating base material 23 is pushed out from the nozzle hole 45. The coating substrate 23 pushed out from the nozzle hole 45 is discharged from the jet nozzle 41 as droplets 46 and sprayed onto the tablets 16 on the transport belt 14.

  Next, the coating process using the coating apparatus 1 according to the present invention will be described. Here, first, a tablet 16 serving as an object to be processed is supplied to the tablet supply unit 15. The tablet 16 is placed on the transport belt 14 by the tablet supply unit 15 and moves as it is below the nozzle head 10. From the nozzle head 10, the coating base material 23 is sprayed on the upper surface of the tablet 16. The droplets 47 ejected from the nozzle head 10 adhere to the surface of the tablet 16 as dots of 1 mm or less. About 500 droplets are simultaneously sprayed from the nozzle head 10 onto the tablet 16, thereby forming a film of the coating base material 23 on the tablet surface.

  In this case, the coating base material 23 is required to be melted so that it can be sprayed at a high temperature by heating, and fluidity is easily secured. On the other hand, when cooled to room temperature, a certain degree of hardness is required so that the coated surfaces do not adhere when they come into contact with each other. For this reason, the coating substrate 23 has a wax (for example, carnauba wax, beeswax, white beeswax, hardened) having a melting point or freezing point of 55 ° C. or higher (both are coincident with a pure substance but not necessarily with an impure substance). Oil, paraffin, stearic acid, stearyl alcohol, etc.) are preferably used. Here, it is preferable to use a low-boiling wax which can be used without a solvent and can be quickly dried.

  In such a wax coating, since the tablet 16 is difficult to disintegrate by wax application, a thin coating layer is sufficient even for a tablet that easily disintegrates, and the coating apparatus 1 is suitable for forming such an extremely thin coating layer. When the tablet 16 is colored, the coating base material 23 is coated with a colorant, fats and oils for adding the colorant, wax dispersion carrier (glycerin, propylene glycol, etc.), wax base material (carnauba wax, etc.). Etc. may be included.

  Further, as the coating base material 23, a substance having a melting point, freezing point or softening point at 55 ° C. or higher (polyethylene glycols, polyoxyethylene, polyoxypropylene glycols, rosin, hydrogenated rosin glycerin ester, ester gum, vinyl acetate Resin etc.) can also be used. In this case, in the case of a resin-based coating substrate such as a hydrogenated rosin glycerin ester, although it is insoluble in water, the impact resistance is somewhat inferior, so the coating layer needs to be thick to some extent. For this reason, in the case of a resin system, it is necessary to take measures such as reducing the speed of the transport belt 14 or increasing the size of the droplets.

  When the coated tablet obtained by the apparatus / method of the present invention is stored at a high temperature such as 50 ° C. or higher, there is a possibility of causing a so-called blocking problem in which the tablets adhere to each other. Such a blocking phenomenon may occur even when using a hydrogenated rosin glycerin ester or the like having a softening point close to 100 ° C. In order to avoid this, for example, solid or powder polishing (glossy polishing) ) It is preferable to carry out a treatment in which the tablets coated with the wax are put into a polishing pan and fluidized while rotating. In this case, examples of the wax for polishing include carnauba wax, paraffin, stearic acid, magnesium stearate, calcium stearate, and the like, and the anti-blocking effect by magnesium stearate is particularly remarkable.

  The coating process by the nozzle head 10 is performed while operating the conveying belt 14, and the tablet 16 is sent to the tablet discharge unit 17 after the coating base material 23 is sprayed under the nozzle head 10. In this case, as can be seen from FIG. 1, depending on the nozzle head 10, only the upper surface side of the tablet 16 is coated, and the lower surface and side surfaces remain untreated. Therefore, in the tablet discharge unit 17, the coated tablet 16 is lowered from the transport belt 14, while the tablet 16 is turned upside down, and the tablet 16 is placed on a transport belt (not shown) installed separately. And the coating process of a tablet back surface side is implemented by another nozzle head.

  On the other hand, for the tablet side surface, the coating processing unit 2 is provided with a side coating head in addition to the nozzle head 10, or a side coating head is provided on the side of a separately installed transport belt. To implement. Note that the side coating may be performed several times by changing the direction of the tablet, or may be performed by rotating the tablet itself. Further, regarding the coating on the upper and lower surfaces, the processing by the nozzle head from above may be repeated several times.

  As described above, in the coating apparatus 1 according to the present invention, the tablet 16 is coated by the jet nozzle 41 using the piezo element 44 while the tablet 16 is being transported by the belt conveyor 11. A film can be continuously formed on the tablet surface in the contact state. For this reason, it is possible to perform a continuous coating process while improving the aesthetics of the tablet and preventing wear and tear, and an efficient coating process with few defective products is possible. In addition, because of non-contact processing, it is possible to perform coating processing on tablets with high friability, soft tablets with low hardness, tablets that are easily disintegrated, and the like, which could not be conventionally coated.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the example in which the jet nozzle 41 using a piezo element is used for the nozzle head 10 has been described. However, as in the case of the ink jet printer, a thermal type nozzle may be used. However, in the case of the thermal method, since it is necessary to apply heat to the coating base material 23, it is necessary to consider the deterioration of the base material due to heat. In general, the thermal method is suitable for improving the printing speed of an ink jet printer, but the tablet coating process does not require a high-speed operation as much as photographic printing. For this reason, when the influence on the coating substrate is taken into consideration, the piezo method is more preferable for the coating process than the thermal method.

It is explanatory drawing which shows the system configuration | structure of the tablet coating apparatus which is one Example of this invention. It is explanatory drawing which shows the structure of the jet nozzle used with the tablet coating apparatus of FIG. It is explanatory drawing which shows operation | movement of a jet nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tablet coating apparatus 2 Coating processing part 3 Coating liquid supply part 4 Control part 10 Nozzle head 11 Belt conveyor (tablet conveyance means)
12 Drive pulley 13 Driven pulley 14 Conveyor belt 15 Tablet supply unit 16 Tablet 17 Tablet discharge unit 21 Hot hose 22 Control line 23 Coating substrate 24 Heating tank 25 Heater 26 Pump 31 Interface unit 32 Bus line 33 CPU
34 Input / output unit 34a Input unit 34b Monitor 35 ROM
36 RAM
41 Jet nozzle (nozzle device)
42a, 42b Partition wall 43 Pressure chamber 44 Piezo element 45 Nozzle hole 46 Droplet

Claims (6)

A tablet coating apparatus for forming a coating substrate film on a tablet surface,
Tablet conveying means capable of continuously conveying tablets in one direction;
A tablet coating apparatus, comprising: a nozzle device that is arranged in the vicinity of the tablet conveying means and that ejects fine droplets of the coating base material onto the tablet by operation of a piezo element.   The tablet coating apparatus according to claim 1, wherein the droplets of the coating base material ejected by the nozzle device have an ejection density of 400 to 700 dpi.   3. The tablet coating apparatus according to claim 1, wherein the coating base material is polyethylene glycols, polyoxyethylene, polyoxypropylene glycols, rosin, hydrogenated rosin glycerin ester, ester gum, vinyl acetate resin, carnauba wax, beeswax. A tablet coating apparatus comprising a substance selected from the group consisting of honey beeswax, hydrogenated oil, paraffin, stearic acid and stearyl alcohol.   A tablet coating method, wherein a fine droplet of a coating substrate is ejected onto a tablet by a nozzle device using a piezo element to form a film of the coating substrate on the tablet surface.   5. The tablet coating method according to claim 4, wherein droplets of the coating base material are sprayed onto the tablet at a spray density of 400 to 700 dpi by the nozzle device.   6. The tablet coating method according to claim 4 or 5, wherein the coating substrate is polyethylene glycols, polyoxyethylene, polyoxypropylene glycols, rosin, hydrogenated rosin glycerin ester, ester gum, vinyl acetate resin, carnauba wax, beeswax. A tablet coating method comprising a substance selected from the group consisting of honey beeswax, hydrogenated oil, paraffin, stearic acid and stearyl alcohol.

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