Tablet coating method and tablet coating system

Abstract

To attain the unmanned and manpower saving of a coating treatment by automatically managing an end point of a spray process of the coating treatment.SOLUTION: Sampling SP1 is performed before coating after a preheating process to measure an initial tablet weight Wi, and a desired coating amount Wc is added thereto to calculate a target tablet weight Wtgt. Sampling SP2 is performed during a spray process to acquire a reference tablet weight Wr. Sampling SP3 is performed after the end of the spray process to acquire a process end tablet weight Wf. When the process end tablet weight Wf is the target tablet weight Wtgt or more, the spray process is completed to move to a next process. When the process end tablet weight Wf is below the target tablet weight, on the basis of the target tablet weight Wtgt and the process end tablet weight Wf, and the process end tablet weight Wf and a reference tablet weight Wr, an additional spray time or an additional spray amount is determined to execute a re-spray process.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a tablet coating process, and more particularly to an endpoint control technique for a film coating process in a pan coating apparatus. [Background technology]

[0002] In coating processes in which tablets are treated, the coating process is controlled by sampling tablets during processing and measuring the weight of the sample obtained. Sampling of the treated objects is performed periodically or as needed during the coating process, and is performed by taking a certain amount of tablet samples from a coating pan (hereinafter abbreviated as "pan" as appropriate). The weight of the sample taken out is measured to calculate the amount of coating film on the tablet surface, and the spray process is completed when the weight of the sample tablet reaches or exceeds a predetermined value, and it is confirmed that the amount of coating is equal to or greater than a predetermined value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2637203 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional coating processes, when a certain amount of tablets is sampled and the amount of coating does not reach the predetermined amount, the worker sets the additional spray time and amount each time and continues the coating process. Further sampling is then performed at a certain cycle, and the end point of the spray process is determined based on the measured value at that time. For this reason, the spray process requires multiple samplings to be performed and the process is managed, which is one of the reasons why the coating process cannot be automated or labor-saving.

[0005] The object of the present invention is to automatically manage the end point of the spray process, thereby contributing to unmanned and labor-saving coating processing. [Means for solving the problem]

[0006] The tablet coating method of the present invention is to coat tablets contained in a coating device. When carrying out the coating process, the end point of the spray process in which the coating liquid is sprayed onto the tablets is automatically controlled. A tablet coating method comprising the steps of: collecting the tablets from the coating apparatus and measuring their weights before spraying the coating liquid; That point in time is designated as the first sampling point SP1, and Weight is the initial tablet weight Wi The initial tablet weight Wi Desired coating amount Wc Add the target tablet weight Wtgt Calculate During the spraying process removing the tablets from the coating apparatus and measuring their weight; That point in time is designated as the second sampling point SP2. See weight Tablet weight Wr Upon completion of the spraying process, the tablets are collected from the coating device and weighed. This point in time is designated as the third sampling point SP3. Weight is the tablet weight at the end of the process. Wf year, At the third sampling point SP3, Weight of tablets at the end of the process Wf is the target tablet weight Wtgt When it is equal to or greater than (Wf≧Wtgt) The spraying process is completed. On the other hand , tablet weight at the end of said process Wf is the target tablet weight Wtgt When less than (Wf <Wtgt) , additional spray time Xt or additional spray amount Xsp Determine and respray treatment At that time, the additional spray time Xt is calculated based on the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and the reference tablet weight Wr, and the time Δt between the second sampling point SP2 and the third sampling point SP3 based on the following formula: Xt=ΔW / (ΔW1 / Δt), and the additional spray amount Xsp is calculated based on the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and the reference tablet weight Wr, and the spray amount ΔW2 of the coating liquid between the second sampling point SP2 and the third sampling point SP3 based on the following formula: Xsp=ΔW / (ΔW1 / ΔW2), thereby automatically controlling the end point of the spray process. It is characterized by:

[0009] Furthermore, after completion of the re-spraying process, the tablets are sampled from the coating apparatus and their weights are measured, and this weight is used as a new end-of-process tablet weight. If the new end-of-process tablet weight is equal to or greater than the target tablet weight, the spraying process is completed. If the new end-of-process tablet weight is less than the target tablet weight, an additional spray amount or additional spray time is determined based on the target tablet weight and the new end-of-process tablet weight, and a further re-spraying process is performed. The re-spraying process may be repeatedly performed until the end-of-process tablet weight is equal to or greater than the target tablet weight.

[0010] In addition, a preheating step of heating the tablet may be carried out before the measurement of the initial tablet weight, and the spraying step may be carried out in a plurality of steps. Weight of tablets at the end of the process may be measured in the final spraying step.

[0011] The tablet coating system of the present invention comprises a coating device having a rotatable processing container, which sprays a coating liquid onto tablets contained in the processing container and performs a coating process on the tablets, a sample obtaining device which collects the tablets from the coating device, a sample weight measuring device which measures the weight of the tablets collected from the coating device by the sample obtaining device, and a control device which controls the coating device, the sample obtaining device, and the sample weight measuring device, and the tablet coating system automatically manages the end point of a spraying process in which a coating liquid is sprayed onto the tablets during the coating process, and the control device calculates the weight of the tablets collected from the coating device based on data obtained from the sample weight measuring device. the tablet weight calculation unit sets the weight of the tablet collected before the start of the spraying process of spraying the coating liquid as an initial tablet weight Wi at a first sampling point SP1; a target tablet weight calculation unit calculates a target tablet weight Wtgt by adding a desired coating amount Wc to the initial tablet weight Wi; a weight comparison unit compares the weights of the tablets calculated by the sample weight calculation unit; a process completion determination unit determines whether the spraying process is complete or whether additional spraying is required based on a comparison result by the weight comparison unit; and an end point calculation instruction unit calculates additional spray time Xt or additional spray amount Xsp and performs a re-spray process when additional spraying is determined to be required by the process completion determination unit, SP3Compare the weight of the tablet taken at that time, i.e., the end-process tablet weight Wf, with the target tablet weight Wtgt. Based on the comparison result between the end-process tablet weight Wf and the target tablet weight Wtgt, when the end-process tablet weight Wf is greater than or equal to the target tablet weight Wtgt (Wf≧Wtgt), the spray process is completed. When the end-process tablet weight Wf is less than the target tablet weight Wtgt (Wf<Wtgt), an additional spray time Xt or an additional spray amount Xsp is determined and a re-spray process is carried out. At this time, the end-point calculation instruction unit calculates the additional spray time Xt based on the difference ΔW between the target tablet weight Wtgt and the end-process tablet weight Wf, the difference ΔW1 between the end-process tablet weight Wf and the reference tablet weight Wr indicating the weight of the tablet taken at the second sampling point SP2 set during the spray process, and the time Δt between the second sampling point SP2 and the third sampling point SP3 according to the following formula: Xt = ΔW / (ΔW1 / Δt). The additional spray amount Xsp is calculated based on the difference ΔW between the target tablet weight Wtgt and the end-process tablet weight Wf, the difference ΔW1 between the end-process tablet weight Wf and the reference tablet weight Wr, and the spray amount ΔW2 of the coating liquid between the second sampling point SP2 and the third sampling point SP3 according to the following formula: Xsp = ΔW / (ΔW1 / ΔW2). By doing so, the end point of the spray process is automatically controlled.

[0014] Furthermore, after the completion of the re-spray process, the process completion determination unit collects the tablet from the coating device, measures its weight, uses the weight as the new end-process tablet weight. When the new end-process tablet weight is greater than or equal to the target tablet weight, the spray process is completed. When the new end-process tablet weight is less than the target tablet weight, based on the target tablet weight and the new end-process tablet weight, an additional spray amount or an additional spray time is determined and a further re-spray process is carried out. The re-spray process may be repeatedly carried out until the end-process tablet weight becomes greater than or equal to the target tablet weight.

[0015] In addition, a preheating step of heating the tablet may be carried out before the measurement of the initial tablet weight, and the spraying step may be carried out in a plurality of steps. Weight of tablets at the end of the process may be measured in the final spraying step. Effect of the Invention

[0016] According to the tablet coating method of the present invention, when a predetermined coating process is completed, the sample tablet weight is compared with the target tablet weight after completion of the spray process to determine whether additional spraying is required. If additional spraying is required, the remaining additional spraying time or additional spray amount is automatically calculated based on the sample tablet weight data obtained up to that point, and a re-spray process is carried out, thereby making it possible to automatically control the endpoint of the coating process.

[0017] According to the tablet coating system of the present invention, when a predetermined coating process is completed, the weight comparison unit compares the sample tablet weight with the target tablet weight after completion of the spray process, and the process completion determination unit determines whether additional spraying is required. If additional spraying is required, the remaining additional spraying time or additional spray amount is automatically calculated based on the sample tablet weight data obtained up to that point, and a re-spray process is performed, making it possible to automatically control the endpoint of the coating process. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a tablet coating system according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a front view of a pan coating apparatus used in the tablet coating system of FIG. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a control device that controls the tablet coating system of FIG. 1. [Figure 4] 2 is a flowchart showing the control process of the coating process in the tablet coating system of FIG. 1. [Diagram 5]FIG. 11 is an explanatory diagram showing an end point control process of a coating process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described. Fig. 1 is an explanatory diagram showing the configuration of a tablet coating system 10 according to one embodiment of the present invention, and the tablet coating method according to the present invention is also carried out by this system. The tablet coating system 10 (hereinafter abbreviated as coating system 10) is a system that performs a film coating process on tablets using a pan coating device 1 (powder and granular material processing device), and the end point of the spray process is automatically managed.

[0020] As shown in FIG. 1, the coating system 10 includes a pan coating apparatus 1 (hereinafter abbreviated as coating apparatus 1), a sample acquiring device 31 that extracts samples from the coating apparatus 1, a sample transporting device 35 that transports the extracted samples and distributes a predetermined number of samples for weight measurement, and a sample weight measuring device 36 that measures the weight of the predetermined number of distributed samples, and is controlled by a control device 41.

[0021] Samples (tablets undergoing coating processing) are taken out from the coating apparatus 1 by a sample acquisition device 31. The taken out sample tablets are sorted into a predetermined number of tablets while being transported by a sample transport device 35, and sent to a sample weight measurement device 36. In the sample weight measurement device 36, the weight of the predetermined number of sample tablets is measured, and the data obtained there is sent to a control device 41 and analyzed.

[0022] The control device 41 detects the coating process status from the weight of the sample tablet, and feedback controls various processing conditions (such as the amount of coating liquid sprayed and the spray time). Furthermore, in the coating system 10, the control device 41 calculates the remaining additional spray time and / or additional spray amount from a preset coating amount based on the weight of the sample tablet, and automatically determines the end point of the coating process. Then, the processing conditions are automatically controlled until the weight of the sample tablet exceeds the preset coating amount.

[0023] The coating apparatus 1 is configured as a jacketless type that uses a so-called fully punched type coating pan (rotating drum: processing vessel) 2. Tablets (processed objects) 3 to be coated are accommodated in the coating pan 2 (hereinafter abbreviated as pan 2), and the tablets 3 are coated by spraying a coating liquid thereon. As shown in FIG. 1, the coating apparatus 1 is configured such that the pan 2 is rotatably installed in a pan chamber 4a of a housing 4. The pan 2 rotates about a substantially horizontal rotation axis O, and the tablets 3 are placed inside the pan.

[0024] Pan 2 comprises a cylindrical body 5 and a truncated conical portion 6 formed on both ends of body 5. Body 5 is made of a stainless steel perforated plate (punched plate), and the outer periphery of body 5 is configured to be ventilated through a large number of ventilation holes 7. Conical portion 6 is made of a stainless steel plate, and a front opening 8 is formed at one end of conical portion 6 (right side in FIG. 1: one end of pan 2). The other end of conical portion 6 (left side in FIG. 1: the other end of pan 2) is closed by end plate 9, and a rotating shaft 11 is attached.

[0025] The left side of the bread chamber 4a in FIG. 1 is the machine chamber 4b, where a drum rotation mechanism (not shown) using an electric drum drive motor is located. As described above, the rotating shaft 11 is fixed to the left end (other end) of the bread 2, and a sprocket (not shown) is attached to this rotating shaft 11. The sprocket is connected via a chain to a sprocket on the motor side installed inside the housing 4. When the motor is rotated, the bread 2 is driven by the chain in response to the rotation, and rotates around the rotation axis O.

[0026] Fig. 2 is a front view of the coating apparatus 1. As shown in Fig. 2, the front of the housing 4 (the right side in Fig. 1) has a three-part structure. A front door 13 is provided in the center of the front of the housing, and unit covers 14a, 14b are provided on both sides of the front door 13. The front door 13 is rotatably supported by one of the unit covers 14a, and is provided so as to be freely opened and closed relative to the housing 4. The unit covers 14a, 14b are also provided so as to be freely opened and closed relative to the housing 4. An inspection door 15 is attached to the front of the front door 13, and a product discharge port 16 for removing the processed product is provided at the bottom of the front door 13.

[0027] The coating apparatus 1 is provided with an air intake section 17 for supplying a process gas into the pan 2, and an exhaust section 18 for discharging the process gas supplied from the air intake section 17 into the pan 2 to the outside of the pan. An air intake duct 19 is connected to the air intake section 17, and hot air or cold air is supplied as the process gas from an air supply device (not shown). The process gas supplied to the air intake section 17 is fed into the pan 2 from the front opening 8 through the air intake chamber 12 formed in the front door 13. An exhaust duct 21 is connected to the exhaust section 18, and the process gas discharged from the pan 2 is sent out of the apparatus through the exhaust duct 21. An air intake damper 22 and an exhaust damper 23 are provided in the air intake duct 19 and the exhaust duct 21, respectively, so that the amount of air supplied to and exhausted from the pan 2 can be appropriately adjusted. In addition, in the coating apparatus 1, a bypass duct 24 is provided between the air intake duct 19 and the exhaust duct 21 to communicate with each other without passing through the pan 2. A bypass damper 25 is provided in the bypass duct 24, and the communication state between the two ducts 19, 21 can be controlled by opening and closing the bypass damper 25.

[0028] A spray gun 26 for spraying the coating liquid is disposed in the pan 2. The spray gun 26 is attached to a gun holder 27, inserted into the pan from the front opening 8 of the pan 2, and is provided so as to be freely inserted and removed from the pan from the front side of the device. The coating liquid and spray air are supplied to the spray gun 26 through a hose (not shown) housed in the gun holder 27. The spray gun 26 moves up and down in the pan 2 in a direction perpendicular to the tablet layer surface, and the coating liquid and the like are appropriately sprayed from a predetermined spray position to the tablets 3 in the pan 2 at a desired timing, thereby carrying out a coating process.

[0029] The coating apparatus 1 is further provided with a sample acquisition device 31 that extracts sample tablets from the pan 2. The sample acquisition device 31 is a suction-type sampling device that sucks up the tablets 3 in the pan 2 with a suction tube 32 extending into the pan 2. The tablets 3 sucked from the pan 2 are stored as samples in a sample storage chamber 33. In the sample storage chamber 33, when suction is stopped, a bottom door 34 opens due to the weight of the sample, and the sample is sent to a sample transport device 35 arranged below the storage chamber. The extracted sample is sorted into a predetermined number of tablets while being sucked and transported by the sample transport device 35 using a transport disk (not shown), and is transported to a sample weight measuring device 36.

[0030] The sample weight measuring device 36 measures the weight of a predetermined number of samples, and the data obtained there is sent to the control device 41, which feedback-controls the coating process conditions. As described above, the control device 41 automatically determines the end point of the coating process and automatically controls the coating device 1. FIG. 3 is a block diagram showing the system configuration of the control device 41. As shown in FIG. 3, the control device 41 has a CPU (Central Processing Unit) 42, which is a system control means, a ROM (Read Only Memory) 42, a RAM (Random Access Memory) 43, a timer 45, etc.

[0031] The ROM 43 stores various programs and data for system control, such as a program for implementing the control method according to the present invention. The RAM 44 appropriately writes data such as the weight of the sample tablet before the coating process (initial tablet weight Wi), the weight of the sample tablet at the completion of the spray process (target tablet weight Wtgt), measurement data in the sample weight measuring device 36, the spray amount, and the spray time. The CPU 42 is provided with a pan control unit 51, a spray control unit 52, a sample acquisition control unit 53, a sample transport control unit 54, a sample weight measurement control unit 55, and a damper control unit 56. The pan control unit 51 controls the motor in the coating device 1 to control the rotation of the pan 2. The spray control unit 52 controls the spray gun 26, and controls the spray amount and spray time from the spray gun 26.

[0032] The sample acquisition control unit 53 controls the sample acquisition device 31 to acquire sample tablets from within the pan 2. The sample transport control unit 54 controls the sample transport device 35 to count the samples acquired from within the pan 2 while transporting them, and send a predetermined amount to the sample weight measuring device 36. The sample weight measurement control unit 55 controls the sample weight measuring device 36 to measure the weight of a predetermined number of samples sent by the sample transport device 35, and send the data to the control device 41. The damper control unit 56 controls the supply damper 22, exhaust damper 23, and bypass damper 25, and controls the supply and exhaust amount of the treatment gas in the pan 2.

[0033] The CPU 42 further includes a coating amount setting unit 61, an initial tablet weight setting unit 62, a target tablet weight calculation unit 63, a sample weight calculation unit 64, a weight comparison unit 65, a process completion determination unit 66, and an end point calculation instruction unit 67. A desired coating amount (increased tablet weight) is input into the coating amount setting unit 61 at the start of the coating process, and 10 mg (per tablet, the same applies below) is set as the "coating amount Wc". The "coating amount Wc" is arbitrarily set by the operator using an operation panel or the like provided on the control device 41.

[0034] The initial tablet weight setting unit 62 acquires the weight of the sample tablet after the preheating step carried out prior to spraying of the coating liquid, and sets this weight as the "initial tablet weight Wi" (e.g., 200 mg). The target tablet weight calculation unit 63 calculates the target tablet weight after the coating process (target tablet weight Wtgt) based on the "coating amount Wc" set in the coating amount setting unit 61 and the "initial tablet weight Wi" acquired and set by the initial tablet weight setting unit 62. Using the previous example, here, the "target tablet weight Wtgt" is calculated and set as Wtgt=Wi+Wc=200+10=210 mg.

[0035] The sample weight calculation unit 64 calculates the current weight of the sample tablet based on the data obtained by the sample weight measurement device 36. Since the weight of the sample tablet is the total value of a predetermined number of tablets (e.g., 100 tablets), the sample weight calculation unit 64 divides the weight data by the number of tablets to calculate and obtain the individual weight of the sample tablet (sample tablet weight) at that time. The weight comparison unit 65 compares the sample tablet weight obtained by the sample weight calculation unit 64 with the "target tablet weight Wtgt" and determines which is larger.

[0036] The process completion determination unit 66 determines whether or not the sample tablet weight has reached the "target tablet weight Wtgt" based on the comparison result in the weight comparison unit 65. If the process completion determination unit 66 determines that the sample tablet weight has not reached the "target tablet weight Wtgt", the end point calculation instruction unit 67 calculates the weight required to reach the target, calculates the additional spray time and additional spray amount, and executes a re-spray process.

[0037] In the coating system 10 configured as above, the coating process is performed and the end point of the process is controlled as follows. FIG. 4 is a flow chart showing the control process of the coating process in the coating system 10. The process in FIG. 4 is automatically executed by the control device 41 based on a control program stored in the ROM 43. In the coating system 10, first, an operator sets the amount of coating to be applied to the tablets to be processed (step S1, hereinafter, step will be abbreviated to S1). Here, the operator sets the "coating amount Wc" (e.g., 10 mg) using an operation panel of the control device 41 or the like. The set "coating amount Wc" is input to the coating amount setting unit 61 and stored in the RAM 44.

[0038] After the coating amount is set, the coating device 1 operates based on a command from the pan control unit 51, and a preheating step is performed prior to spraying of the coating liquid (S2: for example, 30 minutes). In the preheating step, while rotating the pan 2, the damper control unit 56 opens the air intake damper 22 and the exhaust damper 23, and hot air is supplied from the air intake duct 19 through the air intake unit 17 into the pan 2 to heat the tablets 3 in the pan 2. The treatment gas supplied into the pan 2 is exhausted from the exhaust unit 18 to the exhaust duct 21. The preheating step is performed with the bypass damper 25 closed.

[0039] After the preheating step is completed, the first sampling (first sampling point: SP1) is performed to obtain the tablet weight before coating as an initial value (S3). For sampling, the sample acquisition control unit 53 operates the sample acquisition device 31 to collect the tablets 3 from the pan 2. In this case, in the coating system 10, the damper control unit 56 instructs the intake damper 22 and exhaust damper 23 to be closed and the bypass damper 25 to be opened to directly communicate the intake duct 19 and the exhaust duct 21 (similar to the following sampling). This maintains the processing environment in the pan, prevents drying during sampling, and prevents weight from changing, suppressing changes in data. This makes it possible to control the coating process and set the end point based on accurate data, stabilizing and improving product quality.

[0040] Based on instructions from the sample transport control unit 54, a predetermined number (e.g., 100 tablets) of the collected tablet samples are sent by the sample transport device 35 to the sample weight measuring device 36. Based on instructions from the sample weight measurement control unit 55, the sample weight measuring device 36 measures the weight of the sample tablets and sends them to the initial tablet weight setting unit 62. The initial tablet weight setting unit 62 sets the sample tablet weight acquired here as "initial tablet weight Wi" and stores it in the RAM 44 (S4).

[0041] After obtaining the "initial tablet weight Wi" in step S4, the process proceeds to step S5, where the "target tablet weight Wtgt", which is the weight of an individual tablet after the spraying process is completed, is calculated from the "initial tablet weight Wi" and the "coating amount Wc" input in S1. The "target tablet weight Wtgt" is calculated in the target tablet weight calculation unit 63 as "initial tablet weight Wi" + "coating amount Wc" (Wtgt = Wi + Wc), and for example, 200 + 10 = 210 mg is calculated and set as the "target tablet weight Wtgt" and stored in RAM 44 (S5).

[0042] After the "target tablet weight Wtgt" is set in this way, the process proceeds to steps S6 and 7, where the spraying process is carried out. The spraying process is carried out in a number of times (for example, 10 minutes and 5 L seven times) while supplying a treatment gas (hot air or cold air) appropriately under the instruction of the pan control unit 51, the spray control unit 52, and the damper control unit 56 at a predetermined spray amount, spray time, and pan rotation speed (spraying process (1) to (7)). When it is confirmed in step S7 that the spraying process is the final time (the seventh time in the previous example), the process proceeds to step S8, where it is determined whether a predetermined time has passed in the final spraying process (S8), and if the predetermined time has passed (for example, when 5 minutes have passed in a 10-minute spraying process), a second sampling (second sampling point: SP2) is carried out (S9). After the second sampling, the process proceeds to step S10, where the sample tablet weight of the tablet collected in SP2 is measured, and the value is acquired as the "reference tablet weight Wr" and stored in the RAM 44.

[0043] The sampling in S9 is carried out in the middle of the final spraying process, and when the final spraying process (here, the seventh) is completed (S11: Y), the third sampling (third sampling point: SP3) is carried out (S12). After the third sampling, the process proceeds to step S13, where the sample tablet weight of the tablet collected in SP3 is measured, and the value is acquired as the "finished tablet weight Wf" and stored in the RAM 44 (S13). After the "finished tablet weight Wf" is acquired, the weight comparison unit 65 compares the "finished tablet weight Wf" obtained in S13 with the "target tablet weight Wtgt" (S14). At this time, if the "finished tablet weight Wf" has reached the "target tablet weight Wtgt", the process completion determination unit 66 determines that the desired coating process has been performed. Then, the process proceeds to step S15, where the end point calculation instruction unit 67 completes the spraying process and exits the routine. After the spraying process is completed, the coating system 10 performs the next process (drying process, cooling process) in the coating device 1.

[0044] On the other hand, in step S12, if the "tablet weight at end of process Wf" obtained in S13 is less than the "target tablet weight Wtgt", the process proceeds to step S16 and subsequent steps, where additional spray processing is performed. In this case, in step S16, the additional spray time and additional spray amount are calculated based on the difference between the "tablet weight at end of process Wf" in S13 and the "reference tablet weight Wr" or "target tablet weight Wtgt". The additional spray time Xt and additional spray amount Xsp are automatically calculated by the end point calculation instruction unit 67, for example, as follows (see FIG. 5), and stored in the RAM 44. Xt = ΔW / (ΔW1 / Δt) Xsp = ΔW / (ΔW1 / ΔW2) ΔW: Difference between "target tablet weight Wtgt" and "final tablet weight Wf" ΔW1: Difference between "final tablet weight Wf" and "reference tablet weight Wr" ΔW2: Amount of coating liquid sprayed between SP2 and SP3 Δt: Time elapsed from SP2 to SP3

[0045] For example, in the above example, if Wtgt = 210 mg, Wf = 208 mg, Wr = 204 mg, and Δt = 5 minutes, the additional spray time Xt is Xt=(210-208) / {(208-204) / (10-5)} =2.5(min) It is calculated as follows. On the other hand, the additional spray amount Xsp is calculated based on the coating liquid spray amount ΔW2 grasped from the control data in the spray control unit 52.

[0046] In step S16, after calculating the additional spray time or additional spray amount, the process proceeds to step S17, where the spray control unit 52 performs a re-spray process based on the instruction of the end point calculation instruction unit 67, and the additional coating liquid is sprayed. That is, even if the spray process has been completed a predetermined number of times, if additional spraying is necessary, the spray process is extended without being terminated. Then, when the additional spraying is completed (S18: Y), sampling is performed again, and the value is stored in the RAM 44 as a new "finished process tablet weight Wf" (S19). After updating the "finished process tablet weight Wf" in S19, the process returns to step S14, where the value is compared with the "target tablet weight Wtgt". Then, if the updated "finished process tablet weight Wf" is equal to or greater than the "target tablet weight Wtgt", the process proceeds to step S15, and the spray process is completed.

[0047] On the other hand, if the updated "tablet weight at end of process Wf" is still less than the "target tablet weight Wtgt" in step S14, the additional spray process from S16 onwards is performed again. That is, based on the difference between the updated "tablet weight at end of process Wf" and the "target tablet weight Wtgt", further additional spray time and amount are calculated and executed. Therefore, the additional spray process automatically controls the end point of the coating process while feeding back the sample tablet weight in S19 until the "tablet weight at end of process Wf" becomes equal to or greater than the "target tablet weight Wtgt", that is, until the sample tablet weight exceeds a preset coating amount.

[0048] In this way, in the coating method and coating system of the present invention, feedback control of the coating process is performed based on the sample tablet weight and a preset desired coating amount. Then, when a predetermined coating process is completed, the sample tablet weight is compared with the target tablet weight after the spray process is completed to determine whether additional spraying is required. At this time, if additional spraying is required, the remaining additional spraying time or additional spraying amount is automatically calculated and performed based on the sample tablet weight data obtained up to that point. Therefore, the end point of the coating process is automatically controlled and the coating process is automatically completed, which contributes to unmanned operation and labor saving.

[0049] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. For example, the number of sample tablets, initial tablet weight, coating amount, target tablet weight, spray amount, spray time, etc. in the above-mentioned embodiment are only examples, and the present invention is not limited to the above-mentioned values, and these values ​​can be appropriately changed depending on the type of tablet, coating agent, amount of preparation, etc. In addition, in the system, each control is performed using the weight of a single tablet as the sample tablet weight, but the sample tablet weight may be set in units of multiple tablets (e.g., 100 tablets) and controlled. However, even in that case, it is easier to understand and preferable for the setting of the coating amount by the operator and the display of the target tablet weight to be performed in numerical values ​​per tablet. Furthermore, in the above-mentioned control form, an example of sampling three times is shown, but the number of samplings is not limited to three times, and can be appropriately performed after the completion of each spray process or according to the instructions of the operator.

[0050] In addition, in the above embodiment, when sampling tablets from the pan 2, a suction-type sample acquisition device 31 is used, but the sampling method is not limited to this, and any type of device can be used, such as a blow sampling type device that uses compressed air to extract tablets from the pan 2, or a type of device that provides a sample collection port in the pan 2 and extracts tablet samples from there. In addition, in the sample transport device 35, the tablets are transported by disk adsorption, but the transport means is not limited to disks, and various methods such as a belt conveyor, a chute, and air transport can be used. Furthermore, in the above coating device 1, the pan 2 is shown to have a cylindrical body 5, but the shape of the body 5 is not limited to a cylindrical shape, and may be a polygonal column shape such as an octagonal cross section. [Industrial Applicability]

[0051] The present invention can be applied to coating treatment of confectionery such as gum and chocolate, and other foods, in addition to tablets such as medicines and health foods. [Explanation of symbols]

[0052] 1 Pan Coating Equipment 2 Coating pans 3 tablets 4. Chassis 4a Bread Room 4b Machine room 5. Torso 6 Conical part 7. Ventilation holes 8 Front opening 9 End Plate 10 Tablet Coating System 11 Rotation axis 12 Air supply chamber 13 Front Door 14a, 14b Unit cover 15 Inspection door 16 Product outlet 17 Air supply section 18 Exhaust section 19 Air supply duct 21 Exhaust duct 22 Air supply damper 23 Exhaust damper 24 Bypass Duct 25 Bypass damper 26 Spray Gun 27 Gun Holder 31 Sample acquisition device 32 Suction tube 33 Sample Containment Chamber 34 Bottom Door 35 Sample transport device 36 Sample weight measuring device 41 Control device 42 CPU 43 ROM 44 RAM 45 Timer 51 Pan control section 52 Spray control unit 53 Sample acquisition control section 54 Sample transport control section 55 Sample weight measurement control section 56 Damper control section 61 Coating amount setting unit 62 Initial tablet weight setting unit 63 Target tablet weight calculation unit 64 Sample weight calculation section 65 Weight comparison section 66 Process completion determination section 67 End point calculation instruction section O Rotation axis Wc coating amount Wi Initial tablet weight Wtgt Target tablet weight Wr Reference tablet weight Wf Tablet weight at end of process Xt Extra Spray Time Xsp additional spray amount

Claims

1. A tablet coating method for automatically controlling an end point of a spraying process for spraying a coating liquid onto tablets contained in a coating device, comprising: Before spraying the coating liquid, the tablets are sampled from the coating device and their weights are measured. This point in time is designated as a first sampling point SP1, and the weight is designated as an initial tablet weight Wi. A desired coating amount Wc is added to the initial tablet weight W to calculate a target tablet weight Wtgt; During the spraying process, the tablet is taken from the coating device and its weight is measured, the time point being designated as a second sampling point SP2, and the weight is designated as a reference tablet weight Wr; At the end of the spraying process, the tablets are taken from the coating device and their weights are measured. This point is designated as a third sampling point SP3, and the weight is designated as the end-of-process tablet weight Wf. At the third sampling point SP3, when the end-of-process tablet weight Wf is equal to or greater than the target tablet weight Wtgt (Wf≧Wtgt), the spray process is completed. On the other hand, when the end-of-process tablet weight Wf is less than the target tablet weight Wtgt (Wf<Wtgt), an additional spray time Xt or an additional spray amount Xsp is determined to perform a re-spray process. The additional spray time Xt is calculated based on the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and the reference tablet weight Wr, and the time Δt between the second sampling point SP2 and the third sampling point SP3 based on the following formula: Xt=ΔW / (ΔW1 / Δt); The tablet coating method is characterized in that the end point of the spray process is automatically controlled by calculating the additional spray amount Xsp based on the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and the reference tablet weight Wr, and the spray amount ΔW2 of the coating liquid between the second sampling point SP2 and the third sampling point SP3 based on the following formula: Xsp = ΔW / (ΔW1 / ΔW2).

2. 2. The tablet coating method according to claim 1, After the re-spraying process is completed, the tablets are taken from the coating device and their weights are measured, and the weights are regarded as new tablet weights at the end of the process. when the new end-of-process tablet weight is equal to or greater than the target tablet weight, completing the spraying process; When the new end-of-process tablet weight is less than the target tablet weight, an additional spray amount or additional spray time is determined based on the target tablet weight and the new end-of-process tablet weight, and a further re-spray process is performed; A tablet coating method, comprising repeating the re-spraying process until the tablet weight at the end of the process is equal to or greater than the target tablet weight.

3. The tablet coating method according to claim 1 or 2, A tablet coating method, characterized in that a preheating step of warming the tablet is carried out before measuring the initial tablet weight.

4. The tablet coating method according to any one of claims 1 to 3, A tablet coating method characterized in that the spraying process is carried out in multiple steps, and the tablet weight at the end of the process is measured in the final spraying process.

5. a coating device including a rotatable processing container, which sprays a coating liquid onto tablets contained in the processing container to perform a coating process on the tablets; a sample taking device for taking the tablets from the coating device; a sample weight measuring device for measuring the weight of the tablets collected from the coating device by the sample acquiring device; A tablet coating system comprising: a control device that controls the coating device, the sample acquiring device, and the sample weight measuring device; and a control device that automatically controls an end point of a spraying process in which a coating liquid is sprayed onto the tablets during the coating process, The control device includes: a sample weight calculation unit that calculates the weight of the tablet taken from the coating device based on the data acquired from the sample weight measuring device; an initial tablet weight setting unit that sets the weight of the tablet sampled before the start of a spraying process of spraying the coating liquid as an initial tablet weight Wi at a first sampling point SP1; a target tablet weight calculation unit for calculating a target tablet weight Wtgt by adding a desired coating amount Wc to the initial tablet weight Wi; A weight comparison unit that compares the weights of the tablets calculated by the sample weight calculation unit; A process completion determination unit that determines whether the spray process is completed or whether additional spraying is required based on a comparison result in the weight comparison unit; and an end point calculation instruction unit that calculates a further additional spray time Xt or an additional spray amount Xsp and performs a re-spray process when the process completion determination unit determines that additional spray is necessary, The weight comparison unit sets the end of the spray process as a third sampling point SP3, and compares a process end tablet weight Wf indicating the weight of the tablet sampled at that point with the target tablet weight Wtgt, The process completion determination unit completes the spray process when the process end tablet weight Wf is equal to or greater than the target tablet weight Wtgt (Wf≧Wtgt) based on a comparison result between the process end tablet weight Wf and the target tablet weight Wtgt, and determines an additional spray time Xt or an additional spray amount Xsp to perform a re-spray process when the process end tablet weight Wf is less than the target tablet weight Wtgt (Wf<Wtgt). At this time, the end point calculation instruction unit the additional spray time Xt is calculated based on the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and a reference tablet weight Wr indicating the weight of the tablet collected at a second sampling point SP2 set during the spray process, and the time Δt between the second sampling point SP2 and the third sampling point SP3, based on the following formula: Xt=ΔW / (ΔW1 / Δt); The tablet coating system is characterized in that the end point of the spray process is automatically controlled by calculating the additional spray amount Xsp based on the following formula: Xsp = ΔW / (ΔW1 / ΔW2) from the difference ΔW between the target tablet weight Wtgt and the end-of-process tablet weight Wf, the difference ΔW1 between the end-of-process tablet weight Wf and the reference tablet weight Wr, and the spray amount ΔW2 of the coating liquid between the second sampling point SP2 and the third sampling point SP3.

6. 6. The tablet coating system according to claim 5, The process completion determination unit After the re-spraying process is completed, the tablets are taken from the coating device and their weights are measured, and the weights are regarded as new tablet weights at the end of the process. when the new end-of-process tablet weight is equal to or greater than the target tablet weight, completing the spraying process; When the new end-of-process tablet weight is less than the target tablet weight, an additional spray amount or additional spray time is determined based on the target tablet weight and the new end-of-process tablet weight, and a further re-spray process is performed; A tablet coating system characterized in that the re-spraying process is repeated until the tablet weight at the end of the process is equal to or greater than the target tablet weight.

7. 7. The tablet coating system according to claim 5 or 6, A tablet coating system characterized in that a preheating step is carried out to warm the tablets before measuring the initial tablet weight.

8. The tablet coating system according to any one of claims 5 to 7, A tablet coating system characterized in that the spraying process is carried out in multiple steps, and the tablet weight at the end of the process is measured at the final spraying process.

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