TEMPERATURE EVALUATION SYSTEM, AND ARTICLE MANAGEMENT SYSTEM IN WHICH SAME IS USED

The temperature evaluation system is provided with: a read-in device that acquires image data pertaining to the indicator; a storage device that stores the relationship between color density and temperature for each thermosensitive material; and a processing device provided with a color density estimation unit that estimates the color density of the thermosensitive material from the image data, a material identification unit that specifies the thermosensitive material used in the indicator, and a temperature estimation unit that selects, from among the relationships between color density and temperature for each thermosensitive material, the relationship between color density and temperature of the thermosensitive material specified by the material identification unit, and that estimates the highest temperature reached or the lowest temperature reached from the relationship between color density and temperature of the specified thermosensitive material and the color density estimated by the color density estimation unit.

TECHNICAL FIELD

The present invention relates to a temperature evaluation system that evaluates temperature from color density of a thermosensitive material, and an article management system using the temperature evaluation system.

BACKGROUND ART

Environmental conditions such as temperature, humidity, vibration, gas, and atmospheric pressure must be appropriately controlled for some of articles transported from a manufacturing site to a consumption site. For example, some article becomes unsuitable for consumption due to rot or change of taste under a high or low temperature environment. For some article, quality deterioration occurs under a high-humidity environment or an environment containing oxygen at an atmospheric level. Some article is broken when it is vibrated more vigorously than expected.

To address such a problem, a measure is performed during transportation or storage of an objective article. That is, the article is kept in an airtight container, or an air conditioner is used to perform temperature management, humidity management, or vibration management of a transportation container, a transportation track, or a storage chamber.

However, such a condition may be deviated from a management range due to device failure or lack of management. A temperature indicator is thus used to determine whether such deviation occurs.

Patent literature 1 discloses a temperature management method using a thermosensitive component exhibiting different color optical densities depending on temperatures. The patent literature discloses that temperature is managed by applying light having a wavelength corresponding to the absorption wavelength of a color of the thermosensitive component in a colored state and detecting reflected light intensity or transmitted light intensity of the light.

Patent literature 2 discloses a temperature management method for reading storage environment of an article by a temperature management component including a thermosensitive component that is provided on a support surface while exhibiting different color optical densities depending on temperatures, where a plurality of thermosensitive components having different temperature characteristics and time characteristics are provided, and color optical densities of such thermosensitive components are measured, and environment temperature and time of storage of the article are specified through operation based on the respective color optical densities.

CITATION LIST

Patent Literature

Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2000-131152.

SUMMARY OF INVENTION

Technical Problem

The thermosensitive component used in each of the patent literatures 1 and 2 changes its color optical density in response to temperature, and indicates temperature and exposure time by the color optical density. It is therefore possible to specify average storage temperature and the exposure time by measuring the color optical density. However, no consideration is given for measurement of the highest temperature reached or the lowest temperature reached.

The object of the invention is therefore to provide a temperature evaluation device capable of evaluating the highest temperature reached or the lowest temperature reached from the color optical density of the thermosensitive material, and provide an article management system using the temperature evaluation device.

Solution to Problem

To solve the above-described problem, a temperature evaluation system according to the present invention, which evaluates temperature of an indicator using a thermosensitive material, is characterized by including: a read-in device that acquires image data on the indicator; a storage device that stores relationships between color densities and temperatures for respective thermosensitive materials; and a processing device including a color density estimation unit that estimates the color density of the thermosensitive material from the image data, a material identification unit that specifies the thermosensitive material used in the indicator, and a temperature estimation unit that selects a relationship between a color density and a density of the thermosensitive material specified by the material identification unit from among the relationships between the color densities and the temperatures for the respective thermosensitive materials, and estimates highest temperature reached or lowest temperature reached from the relationship between the color density and the density of the specified thermosensitive material and the color density estimated by the color density estimation unit.

Advantageous Effects of Invention

According to the invention, it is possible to provide a temperature evaluation system capable of evaluating the highest temperature reached or the lowest temperature reached from a color optical density of a thermosensitive material, and provide an article management system.

DESCRIPTION OF EMBODIMENTS

Modes for carrying out the invention (hereinafter, referred to as embodiments) are now described in detail while appropriately referring to the drawings. Like reference signs designate the same parts throughout the drawings, and duplicated description is omitted.

First Embodiment

Temperature Evaluation System

FIG. 1shows a configuration of a temperature evaluation system of a first embodiment. The temperature evaluation system10includes a processing device71, a read-in device11that acquires image data74on an indicator30(seeFIGS. 3 to 5) using a thermosensitive material, an input device12, a storage device15, an output device13, and a communication device14that communicates with an external system or the like.

The storage device15stores color density-temperature information16of the thermosensitive material, which indicates a relationship between a color density and a temperature for each thermosensitive material, identification information17of the thermosensitive material (thermosensitive material identification information17), and image data74acquired by the read-in device11. The color density-temperature information16of the thermosensitive material, which relates to a peak characteristic of the temperature to the color density of the thermosensitive material, can be acquired by characteristic analysis as described later. The identification information17of the thermosensitive material includes, for example, ID of the thermosensitive material. The image data74are preferably stored together with time of date of reading, a location, and the like.

The storage device15includes synchronous dynamic random access memory (SDRAM), electrically erasable programmable read-only memory (EEPROM) (registered trademark), SD memory card, and the like.

The input device12is apart that receives an instruction from an operator, and is configured of a button and a touch panel. The input device12can receive information that Cannot be read by the read-in device11. Examples of such information include the identification information17of the thermosensitive material used in the indicator30, and a temperature management condition of an article35(seeFIG. 8) to which the indicator30is attached.

The processing device71includes a color density estimation unit18that estimates color density of the thermosensitive material from the image data74read by the read-in device11, a material identification unit19that specifies the thermosensitive material used in the indicator30, and a temperature estimation unit20that selects a relationship between a color density and a temperature of the thermosensitive material specified by the material identification unit19from among the relationships between the color densities and the temperatures of the respective thermosensitive materials, and estimates the highest temperature reached or the lowest temperature reached from the relationship between the color density and the density of the specified thermosensitive material and the color density estimated by the color density estimation unit18, a characteristic analysis unit72that creates the color density-temperature information16of the thermosensitive material stored in the storage device15, and a code recognition unit73that recognizes various codes, such as a one-dimensional code and a two-dimensional code, provided on the indicator30. The processing device71is embodied by executing a program on a memory by a central processing unit (CPU).

An image detector with a camera or the like can be used as the read-in device11. The read-in device11may be any device capable of reading a color of the thermosensitive material and optical information. The numerical information of a color tone includes the RGB color space, the HSV color space, and the Munsell color space in addition to the CIE color space such as L*a*b* and L*C*h*. When the indicator30indicates the thermosensitive material identification information17by a letter, a numeral, or a code, the read-in device11collectively acquires the thermosensitive material identification information17as the image data74.

The material identification unit19acquires, from the input device12, the identification information17of the thermosensitive material used in the indicator30. When the indicator30also indicates the thermosensitive material identification information17, the material identification unit19acquires the identification information17of the thermosensitive material used in the indicator30from the image data74acquired by the read-in device11.

The output device13, which outputs instruction information for an operator, a reading image, a reading result, and the like, is configured of a display and the communication device14. The output device13receives the highest temperature reached or the lowest temperature reached estimated by the temperature estimation unit20, for example. In the first embodiment, a display device is used as the output device13, so that the above-described results can be output and displayed so as to be checked by an operator or the like. The output device13may be connected to a recording medium such as a semiconductor memory to output and record the results into the recording medium, allowing information to be transferred to another information processing device via the recording medium and processed therein or to be output to another display device and displayed thereon.

Thermosensitive Material

The thermosensitive material changes color in response to temperature change. The thermosensitive material, which can be evaluated by the temperature evaluation system10of the first embodiment, may be any material that irreversibly changes color in a usable temperature range and that changes color density in a gradient manner depending on temperatures. Specifically, the thermosensitive material changes color density at a certain gradient with an increase in temperature at a predetermined temperature or higher, or changes color density at a certain gradient with a decrease in temperature at a predetermined temperature or lower. This is because if a material irreversibly changes color in a usable temperature range, even if temperature reaches the maximum or the minimum and then returns to another temperature, the material can maintain a color-changed state at a temperature of the maximum, the minimum, or a peak value.

The thermosensitive material preferably changes color in a short time after reaching the color change temperature. This is because if the thermosensitive material changes color in a long time after reaching the color change temperature, a color tone of the thermosensitive material may be observed while the color change is still not completed.

For example, a composite including a leuco die as an electron-donating compound, a color developing agent as an electron-accepting compound, and a decoloring agent to control a decoloring temperature range can be preferably used as the thermosensitive material to allow the highest temperature reached or the lowest temperature reached to be estimated by the temperature evaluation system10according to one embodiment of the invention.

FIG. 2shows reversible color change of such a composite with temperature changes. InFIG. 2, the horizontal axis represents temperature, and a vertical axis represents color density. For example, the material shown inFIG. 2decreases its color density at a temperature of Ta1during heating, and gradually changes into a state of the lowest color density (decoloring state) with temperature rise until Ta2. Such a color change occurs when a state of the composite changes from a solid to a liquid. That is, the color change is caused by a melting phenomenon of the composite. Although the melting phenomenon occurs at a melting point of the material, if the melting point has a temperature range, i.e., has a maximum temperature and a minimum temperature, melting of the material is not completed unless temperature reaches the maximum temperature of the melting point. For the material shown inFIG. 2, color density decreases at the minimum temperature Ta1of the melting point of the composite. The material changes into the state of the lowest color density (decoloring state) at the maximum temperature Ta2of the melting point of the composite. This means that the material changes a color state in a gradient manner depending on temperatures. The material melts at the melting point for a certain time that is about several seconds to several minutes at a weight of about several milligrams to several grams while the time depends on the weight and the melting heat of the material.

In other words, color change to the final color-changed state at the melting point is completed in about several seconds to several minutes, and further color change does not occur.

When such a composite is cooled from the decoloring state, the composite maintains the decoloring state until Td, but increases its color density at Tdand changes into a coloring state. That is, the color change of the composite occurs in a reversible manner. However, when a temperature difference exists between the minimum temperature Ta1of the melting point and Td, the color change can be treated in the same manner as in an irreversible manner unless operating temperature becomes lower than Td. Such a reversible color change cycle is generally known as a hysteresis color change phenomenon. The color change at Tdoccurs when the state of the composite changes from the liquid to the solid. That is, the color change is caused by a solidification phenomenon of the composite. Specifically, a preferably usable material has a large temperature difference between the minimum temperature Ta1of the melting point and the solidification point Td, i.e., has a large hysteresis width.

Color density change of the material at the highest temperature reached is described. When temperature changes from the initial temperature Txto the highest temperature reached T and the material is completely melted, the color density reaches a final color-changed state at Tyat which further color change does not occur. Thereafter, even if temperature returns from Tyto Tx, since color density does not change unless temperature becomes higher than Ty, the color density can be maintained at the highest temperature reached.

To achieve such properties, any combination of the leuco dye, the color developing agent, and the decoloring agent may be used without limitation as long as the combination exhibits the hysteresis color change phenomenon as shown inFIG. 2. Specific materials are shown in the following.

The color-developing agent changes a structure of the leuco dye for coloration through contact with the electron-donating leuco dye. The color-developing agent usably includes known color-developing agents for pressure sensitive copying paper or thermal paper. Specific examples of such a color-developing agent may include phenols such as benzyl 4-hydroxybenzoate, 2,2′-biphenol, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, bisphenol A, bisphenol F, bis(4-hydroxyphenyl)sulfide, para-hydroxybenzoate, and gallic acid ester. Any compound can be used without limitation as long as the compound is an electron acceptor and capable of changing a color of the leuco dye. In addition, metallic salts of carboxylic acid derivatives may also be used, such as salicylic acid and salicylate metal salts, sulfonic acids, sulfonate salts, phosphoric acids, phosphate metal salts, acid phosphate esters, acid phosphate metal salts, phosphorous acids; and phosphite metal salts. In particular, the color-developing agent preferably includes agents highly compatible with the leuco dye or the decolorant as described later, specifically organic color-developing agents such as benzyl 4-hydroxybenzoate, 2,2′-biphenol, bisphenol A, and gallic acid esters.

The thermosensitive material according to the first embodiment may include such color-developing agents singly or in combination. Color density of the leuco dye in the colored state can be adjusted through a combination of the color-developing agents. Usage of the color-developing agent is selected depending on a desired color density. For example, the usage may be typically selected within a range from about 0.1 to 100 wt. part for 1 wt. part of the leuco dye.

The decolorant is a compound that can dissociate the bond of the leuco dye and the color-developing agent and can control the coloring temperature of the leuco dye with the color-developing agent. The decolorant is typically solidified in a phase-separated state in a temperature range in which the leuco dye is colored. In a temperature range in which the leuco dye is decolored, the decolorant is melted and exhibits the function of dissociating the bond of the leuco dye and the color-developing agent. The state change temperature of the decolorant is therefore important to control temperature of the thermosensitive material.

Such decolorants may be used singly or in combination. Combination of the decolorants makes it possible to adjust the solidification point and the melting point.

In the first embodiment, a larger difference between the minimum temperature and the maximum temperature of the melting point is more preferable for recording the highest temperature reached. To achieve such a property, combination of two or more decolorants is more preferable than a single material as the decolorant. The combination of two or more decolorants prevents the melting point from having one temperature, leading to a difference between the minimum temperature and the maximum temperature of the melting point.

A material having a large molecular weight such as polymer can also be preferably used as the decolorant. The material having a large molecular weight such as polymer largely has distribution of the molecular weight, accordingly leading to a large temperature range of the melting point. This results in a large difference between the minimum temperature and the maximum temperature of the melting point of the decolorant.

Usage of the decolorant is selected depending on a desired color density. For example, the usage may be typically selected within a range from about 1 to 1000 wt. part for 1 wt. part of the leuco dye.

A fourth material may be used in a combinable manner to increase the difference between the minimum temperature and the maximum temperature of the melting point of the decolorant as long as the material does not impair the color developing property and the decoloring property of the thermosensitive material. Such combined use of the fourth material causes the melting point to have the minimum and the maximum instead of having one temperature, leading to a difference between the minimum temperature and the maximum temperature of the melting point as in the case of the combination of two or more decolorants. A preferred fourth material does not exhibit the color developing property itself. A nonpolar material, which is therefore not an electron acceptor, can be used as such a material. The nonpolar material specifically includes nonpolar solvents such as hexane, benzene, and toluene; oils such as petroleum, mineral oil, and silicone oil; waxes of paraffin series, microcrystalline series, olefin series, polypropylene series, and polyethylene series; and low molecular materials or high molecular materials having many skeletons of propylene, ethylene, styrene, cycloolefin, siloxane, or terpene, and copolymers thereof.

Usage of the fourth material is selected depending on a desired property of the melting point. For example, the usage may be typically selected within a range from about 0.1 to 1000 wt. part for 1 wt. part of the leuco dye.

The invention does not limit types or configurations of such materials, and any material can be used as long as the material changes a color state in a gradient manner depending on temperatures.

Indicator Using Thermosensitive Material

The indicator30(seeFIGS. 3 to 5) using the thermosensitive material may be any indicator configured of the thermosensitive material and allowing temperature change to be detected through color change of the indicator. Since the temperature evaluation system10needs to acquire the identification information17of the thermosensitive material, the indicator30preferably has the thermosensitive material identification information17. The thermosensitive material identification information17may be represented by numerals or letter strings or in a form of a one-dimensional code or a two-dimensional code.

FIGS. 3 to 5each show a top view of an indicator according to one embodiment. The indicator30is configured by a one-dimensional or two-dimensional code34and thermosensitive materials31,32, and33. In the one-dimensional or two-dimensional code, a letter string of numerals and/or alphabets is represented as a pattern. The one-dimensional or two-dimensional code may have data Concerning the number, a type, and a position of the thermosensitive material in addition to the thermosensitive material identification information17. Although various standards exist for the code in addition to dimension, the invention does not depend on such standards. Further, although various conversion processing methods may each be performed for patterning the letter string, the invention does not depend on such processing methods.

Although a position, a shape, size, the number, and the like of the thermosensitive material are not limited, they are each preferably easy to be captured in a form of an image together with the code during data reading. For example, the position is preferably in the vicinity of the code. The shape may include any shape without limitation, such as a rectangle, a circle, an ellipse, and a round-corner rectangle. The size is preferably larger than a size of a bar or a dot of the code. The size may be increased to facilitate visual check. It is possible to grasp a plurality of environmental conditions at a time by arranging a plurality of environmentally changeable portions having different changing conditions. Possible examples of such portions include a plurality of portions changing at different temperatures, and a combination of temperature and humidity. The thermosensitive materials may have either the same shape or size, or different shapes or sizes. For the one-dimensional code, since data reading may be linearly performed, as shown inFIG. 4, height of each thermosensitive material is preferably aligned with the length of the bar of a barcode while the thermosensitive materials are arranged in the same direction as arrangement of the bars, but the invention is not limited to such arrangement.

Each of the indicators30may be formed by directly printing the thermosensitive material on the article35(seeFIG. 8), or may be formed in such a manner that the thermosensitive material is printed on a seal and the seal is stuck on a commodity. In addition, a letter string represented by a code may be printed near the code in a letter form. The changing color is preferably additionally written by letters or the like with a color in a range of an appropriate environmental condition and a color under a condition deviating from the condition.

Data Processing Method

The color density-temperature information16of the thermosensitive material stored in the storage device15can be obtained by conversion from sample data of color density against temperature of the thermosensitive material to a graph showing a characteristic of the color density against the temperature and an error range, for example. In this description, the graph showing the characteristic of the color density against the temperature is referred to as characteristic graph. The characteristic graph is preferably recorded in the storage device15in a data format including a parameter value of a type or a coefficient of a function such as a polynomial function or an exponential function and a parameter value of weight or threshold of a Radial Basis Function Network or a neural network NW. The error range is recorded in a form of statistical dispersion, 3σ, or the maximum and the minimum of a sample data.

FIG. 6shows an example of sample data for color densities of an RGB color sample.FIG. 6shows the color densities of red, green, and blue at various temperatures in a table format.

FIG. 7shows an example of a characteristic graph converted from the sample data. In the characteristic graph ofFIG. 7, dots represent the sample data, and the solid straight or curved line has a minimum distance from any of the sample data. In this description, the straight line or the curved line is referred to as characteristic curve. The characteristic curve can be obtained by a regression analysis method, such as linear regression, k-nearest neighbor algorithm, regression tree, neural network, support vector regression, projection pursuit regression, and random forest. The error range can be obtained by a typical method such as dispersion of sample data and Bayesian analysis. Since the Characteristic graph and the error range are each different depending on channels representing the color density, such as R, G, and B of the RGB color sample, the data are preferably recorded for each channel.

The characteristic graph and the error range as shown inFIG. 7may be obtained from a database outside the temperature evaluation system10via the network NW, or may be created within the processing device71of the temperature evaluation system10. In the temperature evaluation system10including the characteristic analysis unit72in the processing device71, the characteristic graph can be created in the processing device71.

In the first embodiment, a method of creating the characteristic graph in the processing device71is described. First, sample data of the color density against the temperature of the thermosensitive material as shown in FIG.6is received by the input device12. The characteristic analysis unit72analyzes the received sample data and creates the characteristic graph and the error range. The created characteristic graph and error range are stored in the storage device15as the color density-temperature information16of the thermosensitive material. The read-in device11reads the image data74on the indicator30(seeFIGS. 3 to 5) using the thermosensitive material. The image data74are stored in the storage device15.

The color density estimation unit18estimates color density of the thermosensitive material from the read image data74.

The material identification unit19specifies the thermosensitive material used in the indicator30. When the thermosensitive material identification information17is received by the input device12, the material identification unit19specifies the thermosensitive material based on the identification information. When the indicator30displays the thermosensitive material identification information17, the thermosensitive material is specified based on the image data74read by the read-in device11. When the indicator30displays the thermosensitive material identification information in a form of a one-dimensional code or a two-dimensional code, the information represented by the code is acquired by the code recognition unit73in the processing device71. The material identification unit19specifies the thermosensitive material based on the information acquired by the code recognition unit73.

The temperature estimation unit20estimates temperature corresponding to the color density estimated by the color density estimation unit18from the characteristic graph showing a relationship between temperature and color density of the thermosensitive material specified by the material identification unit19and the error range of the graph. InFIG. 7, the highest temperature reached of management temperature is estimated using a value of the channel R in the RGB color sample. In the characteristic curve ofFIG. 7, the highest temperature reached corresponding to the R channel value D′ is represented by T′, and the error range is represented by T1to T2. The estimated highest temperature reached is stored in the storage device15.

The estimated highest temperature reached may be output to a display or the like by the output device13, or may be transmitted to an external system via the communication device14.

The temperature evaluation system10of the first embodiment can be achieved by a versatile smartphone having a camera, a screen, and the communication device14. However, the invention is not limited to such an embodiment.

Article Management System

An article management method and an article management system each using the temperature management system are described below.FIG. 8shows a block diagram of the article management system of the first embodiment. The article management system101includes the temperature evaluation system10, a management server40(management device), and management terminals61to68, where the temperature evaluation system10, the management server40, and the management terminals61to68are communicatively connected together via the network NW. The management terminals61to68are disposed at the respective carriage bases of the article35. The management server40includes a processing unit41, a storage unit42, an input unit, an output unit, and a communication unit. The management terminals61to68each include a processing unit, a storage unit, an input unit, an output unit, and a communication unit.

The method and the system are described with exemplary quality control in a distribution route in which the article35is manufactured in a factory, carried to a store, managed in the store, and then provided to a customer.

The article35is produced in the factory and delivered to the store via a warehouse that keeps the article35, a shipping house, a first guided vehicle, a transshipment point in which the article35is transshipped to a second guided vehicle, and the second guided vehicle. In each site, an operator collects temperature data of the article35using one of the management terminals61to68. As described above, the indicator30is attached to the article35.

The temperature data are collected at various timings, for example, when the article35is manufactured in the factory, before shipping in the shipping house, just before the article is carried by the first guided vehicle from the shipping house, just after the guided vehicle has carried the article to the transshipment point, just before the article is carried from the transshipment point to the shop, just after the second guided vehicle has carried the article to the store (when the article arrives at the store), and when the article is kept for sale in the store67.

In each base, an operator can check a color tone of the thermosensitive material to visually check a temperature management condition in each process and a temperature load state of the article35. In addition to such visual check, the operator acquires the image data74(seeFIG. 1) of the thermosensitive material using the temperature evaluation system10and estimates the highest temperature reached or the lowest temperature reached. The information of the estimated highest temperature reached or the lowest temperature reached is transmitted to the management server40that then stores the information as temperature management information. The management server40swaps information with the temperature evaluation system10and the management terminals61to68.

Consequently, a manager can acquire the highest temperature reached or the lowest temperature reached in a distribution process of the article35to be managed. In addition, an operator in each base can connect to the management server40via one of the management terminals61to68to check the temperature management information up to delivery of the article35.

To summarize, the article management system101of the first embodiment includes the temperature evaluation system10that collects the color tone information of the thermosensitive material attached to the article35to acquire the color tone information, and estimates the highest temperature reached or the lowest temperature reached of the article35, the management device (for example, management server40) that manages environment in which the article35is placed, and the management terminal40displaced in each base. Consequently, it is possible to centrally manage the temperature-indicating data acquired at each site in a distribution stage.

When the highest temperature reached or the lowest temperature reached is determined to be deviated from the management temperature range of the article35, the display unit of each of the management terminals61to68may display that the article35is not appropriate for distribution. Consequently, an operator at each site in the distribution stage can instantly check whether an article35is currently appropriately transported.

Second Embodiment

A second embodiment is described with a temperature evaluation system10capable of obtaining the color density-temperature information16of the thermosensitive material from an external database75of the temperature evaluation system10via the network NW.

FIG. 9shows a configuration of the temperature evaluation system10of the second embodiment. The communication device14connects to the external database75via the network NW.

When the temperature estimation unit20recognizes that the color density-temperature information16on the thermosensitive material specified by the material identification unit19is not stored in the storage device15, it obtains the color density-temperature information16on the thermosensitive material specified by the material identification unit19from the external database75, and stores the information16in the storage device15. If the characteristic graph is also not stored in the external database75, the temperature estimation unit20obtains sample data of color density corresponding to temperature, and allows the characteristic analysis unit72(seeFIG. 1) to create a characteristic graph and an error range, and stores, in the storage device15, the created characteristic graph and error range as the color density-temperature information16of the thermosensitive material.

When the temperature estimation unit20recognizes that the color density-temperature information16on the thermosensitive material specified by the material identification unit19is stored in the storage device15, it estimates the highest temperature reached or the lowest temperature reached from the color density-temperature information16of the thermosensitive material stored in the storage device15, the thermosensitive material identification information17, and the color density of the image data74.

Third Embodiment

Temperature Evaluation System

A third embodiment is described with a temperature evaluation system10that predicts remaining life of the article35(seeFIG. 8), to which the indicator30(seeFIGS. 3 to 5) is attached, from the estimated highest temperature reached or lowest temperature reached, and reexamines a management condition of the article35from the remaining life.

FIG. 10shows a configuration of a temperature evaluation system10of a third embodiment. The temperature evaluation system10of the third embodiment includes the read-in device11, the input device12, the output device13, the communication device14, the storage device15, and the processing device71. The processing device71includes the color density estimation unit18, the material identification unit19, and the temperature estimation unit20, and further includes a life prediction unit21that predicts remaining life of the article35, to which the indicator30is attached, based on the highest temperature reached or the lowest temperature reached estimated by the temperature estimation unit20, and a management condition calculation unit22that calculates a management condition of the article35based on the remaining life.

The temperature evaluation system10of the third embodiment estimates the highest temperature reached or the lowest temperature reached by the method described in the first or second embodiment.

The life prediction unit21predicts the remaining life of the article35from data on quality of the article35, such as manufacturing date of the article35, a management temperature range, and expiration date (a best-before date, a use-by date), and from the highest temperature reached or the lowest temperature reached. The predicted remaining life is stored in the storage device15.

When the article35requiring temperature management is transported, a management temperature range is set. If temperature is deviated from the set temperature management range only for a short time, quality of the article35may not be significantly affected. From such a background, a method for predicting a remaining life using a product of the amount and time deviated from the management temperature range is used in a distribution field. In this case, a threshold is beforehand set, and quality of the article35is determined based on whether the product of the amount and the time deviated from the management temperature range exceeds the threshold. For example, when the threshold is set to 50 for the article35required to be managed at a temperature of −5° C. or lower, remaining life L is obtained by a method that is described below using Formulas (1) and (2).

In the formulas, h is threshold, Kexis deviation temperature from the management temperature range, Kmaxis the highest temperature reached, Klimis the highest temperature in the management temperature range, and T is time for which temperature is deviated from the management temperature range. A larger numerical value of the remaining life L means a longer remaining life. In the third embodiment, a problem in quality is determined to occur in the case of the remaining life L≤0.

For example, when the article35is kept for 10 min at 0° C., since Kmax=0° C. and Klim=−5° C. are given, Kex=5 is obtained. Since the threshold h=50 is given, the remaining life L=50−5×10=0 is obtained. The remaining life L=0 reveals that the article35has a quality problem. When the article35is kept for 4 min at 0° C., the remaining life L=50−5×4=30 is obtained. This reveals that although the commodity is deviated from the management temperature range for a certain time, since the deviation time is short, the commodity still has a remaining life. If the thermosensitive material does not change color, Kmax≤Klimis established and thus the life Kex=0 is given; hence, the remaining life L=the threshold h is obtained.

The threshold h corresponds to the permissible amount of the deviation amount from the management temperature range. When the article35to be transported is a food, the threshold is preferably set from a breeding condition of abacillus, a quality deterioration condition, or the like.

The deviation time from the management temperature range can be obtained by further using a data logger mounted in a guided vehicle or a time indicator30. If the deviation time from the management temperature range is unknown, elapsed time from manufacturing of the commodity or the like may be used instead.

The management condition calculation unit22calculates a management condition to maintain quality of the article35based on the remaining life L predicted by the life estimation unit, and records the management condition in the storage device15.

The management temperature condition can be calculated using the following formula, for example.

In the formula, Krngis a management temperature condition, Tremis prediction time for transportation of the article35, and Kmrgis a temperature margin (permissible temperature range). The temperature margin is preferably set on the basis of a detection error caused by air conditioner performance, disturbance, or the like.

For example, when the threshold is set to 50 for the article35required to be managed at a temperature of −5° C. or lower, and when the remaining life L is 30, expected time for transportation of the article35is 60 min, and the temperature margin is 2° C., Krng=30/60−2+(−5)=−6.5 is given. This reveals that the upper limit of the management temperature during transportation of the article is preferably reduced to −6.5 C. The calculation method of the management condition is not limited to the above-described method.

The output device13outputs the calculated management condition. An operator can check the management condition output by the output device13to change a management condition during transportation of the article and resultantly suppress deterioration in quality of the article35.

Article Management System

An article management system using the above-described temperature management system i s described below. As shown inFIG. 8, the article management system101includes the temperature evaluation system10, the management server (management device)40, and the management terminals61to68, where the temperature evaluation system10, the management server40, and the management terminals61are communicatively connected together via the network NW. The management terminals61to68are disposed at the respective carriage bases of the article35. The management server40includes a processing unit41, a storage unit42, an input unit, an output unit, and a communication unit. The management terminals61to68each include a processing unit, a storage unit, an input unit, an output unit, and a communication unit.

In each base, an operator acquires the image data74of the thermosensitive material using the temperature evaluation system10, and estimates the highest temperature reached or the lowest temperature reached. The operator further estimates the remaining life of the article35, and reexamines the management condition of the article35. Information such as the estimated highest temperature reached or lowest temperature reached, the remaining life of the article35, and the reexamined management condition are transmitted to the management server40, and recorded in the storage unit42of the management server40. The management server40swaps the information with the temperature evaluation system10and the management terminals61to68.

Consequently, a manager can acquire the highest temperature reached or the lowest temperature reached in a distribution process of the article35to be managed, the remaining life of the article35, and the reexamined management condition. In addition, an operator in each base can connect to the management server40through one of the management terminals61to68to check the estimated highest temperature reached or lowest temperature reached, the remaining life of the article35, and the reexamined management condition.

Fourth Embodiment

Although the third embodiment has been described with the article management system101in which the processing device71of the temperature evaluation system10includes the life prediction unit21and the management condition calculation unit22, a fourth embodiment is described with an article management system101including the management server40, the management terminals60to68, and the read-in device11.

FIGS. 11 and 12each show a block diagram of the article management system101. As shown inFIGS. 11 and 12, the article management system101includes the read-in device11that acquires the image data74of the indicator30attached to the article35and using the thermosensitive material, the management server40, and the management terminal60disposed in each carriage base of the article35. The read-in device11, the management server40, and the management terminal60are connected together via the network NW.

The read-in device11acquires the image data74of the indicator30in each base.

As shown inFIG. 12, the management server40includes the input device12, the output device13, the communication device14, the storage device15that stores relationships between color densities and temperatures for respective thermosensitive materials, and the processing device71. The processing device71of the management server40includes a color density estimation unit18that estimates color density of the thermosensitive material from the image data74, a material identification unit19that specifies the thermosensitive material used in the indicator30, and a temperature estimation unit20that selects a relationship between a color density and a temperature of the thermosensitive material specified by the material identification unit19from among the relationships between the color densities and the temperatures of the respective thermosensitive materials, and estimates the highest temperature reached or the lowest temperature reached from the relationship between the color density and the density of the specified thermosensitive material and the color density estimated by the color density estimation unit18. The processing device71of the management device40further includes the characteristic analysis unit72(seeFIG. 1) that creates the color density-temperature information16of the thermosensitive material stored in the storage device15, the code recognition unit73(seeFIG. 1) that recognizes various codes, such as a one-dimensional code and a two-dimensional code, provided on the indicator30, the life prediction unit21that predicts remaining life of the article35, to which the indicator30is attached, based on the highest temperature reached or the lowest temperature reached estimated by the temperature estimation unit20, and the management condition calculation unit22that calculates a management condition of the article35based on the remaining life.

The management terminal60includes a processing device81, a communication device82, an output device83, an input device84, and a storage device85. The communication device82of the management terminal60receives from the management device40the information such as the highest temperature reached or the lowest temperature reached estimated or calculated by the management device40, the remaining life of the article35, and the management condition of the article35, and outputs the information from the output device83.

As described above, the temperature evaluation system10or the management device40includes the life prediction means and the management condition calculation means, thereby the highest temperature reached or the lowest temperature reached estimated by the temperature evaluation system10can be fed back to article management.

LIST OF REFERENCE SIGNS