diff --git a/src/main/kotlin/info/nukoneko/kidspos/receipt/ReceiptPrinter.kt b/src/main/kotlin/info/nukoneko/kidspos/receipt/ReceiptPrinter.kt
index 1ba91b9..6a75f88 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/receipt/ReceiptPrinter.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/receipt/ReceiptPrinter.kt
@@ -87,7 +87,10 @@ class ReceiptPrinter(
 
     @Throws(IOException::class)
     fun print() {
-        Socket(ipOrHost, port).use { socket ->
+        Socket().apply {
+            soTimeout = 5000 // 5秒でタイムアウト
+            connect(java.net.InetSocketAddress(ipOrHost, port), 5000) // 接続タイムアウト5秒
+        }.use { socket ->
             socket.getOutputStream().use {
                 it.write(command.build())
             }
diff --git a/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/ItemApiController.kt b/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/ItemApiController.kt
index d42b6e0..198bec8 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/ItemApiController.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/ItemApiController.kt
@@ -101,13 +101,13 @@ class ItemApiController {
         ],
     )
     fun findByBarcode(
-        @Parameter(description = "Item barcode (4+ digits)", required = true, example = "1234567890")
+        @Parameter(description = "Item barcode (format: A01XXXXXXA)", required = true, example = "A01000001A")
         @PathVariable barcode: String,
     ): ResponseEntity<ItemResponse> {
         logger.info("Fetching item with barcode: {}", barcode)
 
-        // Validate barcode format
-        if (!barcode.matches(Regex("^[0-9]{4,}$"))) {
+        // Validate barcode format (A + 種別(2桁) + ID(6桁) + A)
+        if (!barcode.matches(Regex("^A(00|01|02)\\d{6}A$"))) {
             throw InvalidBarcodeException(barcode)
         }
 
diff --git a/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/SaleApiController.kt b/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/SaleApiController.kt
index a02dc14..6060ae8 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/SaleApiController.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/server/controller/api/SaleApiController.kt
@@ -11,8 +11,10 @@ import info.nukoneko.kidspos.server.service.mapper.SaleMapper
 import jakarta.validation.Valid
 import org.slf4j.LoggerFactory
 import org.springframework.http.ResponseEntity
+import org.springframework.scheduling.annotation.Async
 import org.springframework.validation.annotation.Validated
 import org.springframework.web.bind.annotation.*
+import java.util.concurrent.CompletableFuture
 
 /**
  * 販売APIコントローラー
@@ -50,12 +52,18 @@ class SaleApiController(
                 )
             when (val result = saleProcessingService.processSaleWithValidation(saleBean, items)) {
                 is SaleResult.Success -> {
-                    // Print receipt
-                    receiptService.printReceipt(
-                        request.storeId,
-                        items,
-                        request.deposit,
-                    )
+                    // Print receipt asynchronously (non-blocking)
+                    CompletableFuture.runAsync {
+                        try {
+                            receiptService.printReceipt(
+                                request.storeId,
+                                items,
+                                request.deposit,
+                            )
+                        } catch (e: Exception) {
+                            logger.error("Failed to print receipt asynchronously", e)
+                        }
+                    }
 
                     val sale = result.sale
                     val response =
diff --git a/src/main/kotlin/info/nukoneko/kidspos/server/entity/SaleEntity.kt b/src/main/kotlin/info/nukoneko/kidspos/server/entity/SaleEntity.kt
index 19cb4e7..f8e8bfb 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/server/entity/SaleEntity.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/server/entity/SaleEntity.kt
@@ -14,6 +14,7 @@ import java.util.*
  * @property quantity 数量
  * @property amount 売上げ金額
  * @property deposit 預かり金
+ * @property changeAmount お釣り
  * @property createdAt 作成日時
  */
 @Entity
@@ -23,6 +24,7 @@ data class SaleEntity(
     val storeId: Int, // 店舗ID
     val quantity: Int, // 数量
     val amount: Int, // 売り上げ
-    val deposit: Int,
+    val deposit: Int, // 預かり金
+    val changeAmount: Int, // お釣り
     val createdAt: Date,
 )
diff --git a/src/main/kotlin/info/nukoneko/kidspos/server/service/SalePersistenceService.kt b/src/main/kotlin/info/nukoneko/kidspos/server/service/SalePersistenceService.kt
index 96adf97..6075643 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/server/service/SalePersistenceService.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/server/service/SalePersistenceService.kt
@@ -36,6 +36,7 @@ class SalePersistenceService(
         val saleId = idGenerationService.generateNextId(saleRepository)
         val totalAmount = saleCalculationService.calculateSaleAmount(items)
         val quantity = saleCalculationService.calculateQuantity(items)
+        val changeAmount = saleCalculationService.calculateChange(saleBean.deposit, totalAmount)
 
         val sale =
             SaleEntity(
@@ -44,6 +45,7 @@ class SalePersistenceService(
                 quantity = quantity,
                 amount = totalAmount,
                 deposit = saleBean.deposit,
+                changeAmount = changeAmount,
                 createdAt = Date(),
             )
 
diff --git a/src/main/kotlin/info/nukoneko/kidspos/server/service/SaleService.kt b/src/main/kotlin/info/nukoneko/kidspos/server/service/SaleService.kt
index 00b837c..0461278 100644
--- a/src/main/kotlin/info/nukoneko/kidspos/server/service/SaleService.kt
+++ b/src/main/kotlin/info/nukoneko/kidspos/server/service/SaleService.kt
@@ -64,13 +64,16 @@ class SaleService(
         items.forEach {
             logger.debug("Item - ID: {}, Name: {}, Price: {}", it.id, it.name, it.price)
         }
+        val totalAmount = items.sumOf { it.price }
+        val changeAmount = saleBean.deposit - totalAmount
         val sale =
             SaleEntity(
                 id,
                 saleBean.storeId,
                 items.size,
-                items.sumOf { it.price },
+                totalAmount,
                 saleBean.deposit,
+                changeAmount,
                 Date(),
             )