Abstract:
A sewing machine control device includes a control unit for controlling the execution of a sewing operation based on sewing data including at least needle drop point data and thread color data of a sewing thread by selectively using a plurality of sewing needles respectively set with different color thread; a sewing needle-thread color storage medium storing sewing needle-thread color mapping data specifying the relation between sewing needles and thread color of thread respectively set thereto; a similarity evaluation unit for evaluating the similarity between the thread color specified by the thread color data and the thread color set to each sewing needle based on the thread color data and the sewing needle-thread color mapping data; and a sewing needle selection unit for selecting the sewing needle used for sewing in accordance with the sewing data based on evaluation result rendered by the similarity evaluation unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-060816, filed on Mar. 4, 2005 the entire contents of which are incorporated herein by reference. 
   TECHNICAL FIELD 
   The disclosure relates to a sewing machine control device and a multi-needle sewing machine that execute a sewing operation by selectively using a plurality of sewing needles in accordance with sewing data including needle drop point data and thread color data. 
   BACKGROUND 
   Conventionally, a multi-needle sewing machine has been used which is capable of consecutively sewing embroidery patterns that require the use of a plurality of thread colors. Such multi-needle sewing machine is provided with sewing data and a plurality of sewing needles. The sewing data includes thread color data that specifies a thread color and needle drop point data that specifies a needle drop point position for each stitch. A plurality of sewing needles is respectively attached to needle bars which are each set with a thread of different color. 
   The multi-needle sewing machine loads the sewing data upon starting a sewing operation. Then a switch is made to the sewing needle set with a thread having a thread color that matches with the loaded thread color data, and sewing operation is executed based on the loaded needle drop point data. Such sewing needle switching is carried out when replacing the thread color to be used for a sewing process. At this point, in case a sewing needle set with a thread that matches with the thread color specified in the thread color data does not exist, the user makes the replacement to the thread having a matching thread color. 
   A multi-needle sewing machine disclosed in JP-A-6-15072 is provided with a storage medium that stores thread type (thread color) data of the thread set to the sewing needle. The multi-needle sewing machine loads the sewing data upon embroidery sewing. Then, in case the sewing needle set with the thread having the thread color matching the thread color data specified in the sewing data does not exist, sewing operation is stopped to enable the replacement of the thread spool by the user. 
   Similarly, a sewing machine control device disclosed in JP-A-2004-33538 stops the sewing operation when a sewing needle set with a thread having a thread color matching the thread color data specified in the sewing data does not exist. Then, in the subsequent sewing operation, the sewing needle set with the least frequently used thread color is determined. Then the user is informed of a specific thread spool to be replaced so that highest replacement efficiency can be attained. 
   The thread replacement described above requires the user to set the sewing needle with the thread in addition to the replacement of the thread spool itself, which is a troublesome work for the user. Performing such operation upon every absence of matching thread color imposes considerable burden on the part of the user. 
   SUMMARY 
   Therefore an object of the present disclosure is to provide a sewing machine control device and a multi-needle sewing machine capable of reducing the user&#39;s burden upon thread replacement work in case a sewing needle set with a thread having a thread color matching with the thread color specified in thread color data of sewing data does not exist, or in case a sewing needle set with a thread having a thread type matching the thread type specified in thread specification data of the sewing data does not exist. 
   The sewing machine control device of the present disclosure is provided with a control unit that controls the sewing machine so as to execute a sewing operation by selectively using a plurality of sewing needles respectively set with a thread of different color based on the sewing data which at least includes needle drop point data and thread color data of the thread to be used for a sewing process; and a sewing needle-thread color storage medium that stores sewing needle-thread color mapping data capable of specifying a correspondence between the plurality of sewing needles and the thread color of the thread respectively set to each sewing needle. The control device of the sewing machine is further provided with a similarity evaluation unit that evaluates the similarity between the thread color specified by the thread color data and the thread color of the thread set to each sewing needle based on the thread color data and the sewing needle-thread color mapping data; and a sewing needle selection unit that selects, based on the evaluation result rendered by the similarity evaluation unit, the sewing needle to be used for the sewing process performed in accordance with the sewing data. 
   According to such construction, among the plurality of sewing needles set with threads of different thread colors, a sewing needle set with a thread which is similar to the thread color specified by the thread color data is determined as the sewing needle to be used for the sewing process. As a result, sewing can be performed with a similar thread color without thread replacement, thereby reducing the user&#39;s burden of thread replacement. 
   Also, the multi-sewing needle machine of the present disclosure is provided with a plurality of sewing needles respectively set with a thread of different type; a control unit that controls the sewing machine so as to execute a sewing operation by selectively using the plurality of sewing needles based on the sewing data which at least includes needle drop point data and thread specification data that specifies the type of thread to be used for a sewing process; and a sewing needle-thread type storage medium that stores sewing needle-thread type mapping data capable of specifying a correspondence between the plurality of sewing needles and the thread type of the thread respectively set to each sewing needle. The multi-needle sewing machine is further provided with a similarity evaluation unit that evaluates the similarity between the thread type specified by the thread specification data and the thread type of the thread set to each sewing needle based on the thread specification data and the sewing needle-thread type mapping data; and a sewing needle selection unit that selects the sewing needle to be used in the sewing process in accordance with the sewing data based on the evaluation result rendered by the similarity evaluation unit. 
   According to such construction, among the plurality of sewing needles set with threads of different thread types, the sewing needle set with the thread which is similar to the thread type specified by the thread specification data is determined as the sewing needle to be used for the sewing process. As a result, sewing can be performed with a similar thread type without having to replace the thread, thereby reducing the user&#39;s burden of thread replacement. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present disclosure will become clear upon reviewing the following description of the illustrative aspects with reference to the accompanying drawings, in which, 
       FIG. 1  is a perspective view of the disclosure, wherein a multi-needle sewing machine provided with a sewing machine control device is shown; 
       FIG. 2  is a block diagram of control systems of the multi-needle sewing machine; 
       FIG. 3  is a data structure of sewing data including thread color data and needle drop point data; 
       FIG. 4  shows data contained in a table storing sewing needle-thread color mapping data; 
       FIG. 5  shows data contained in a table storing RGB value preset for each thread color for identifying a thread color; 
       FIG. 6A  is the first half of a flow chart for sewing needle selection control; 
       FIG. 6B  is the second half of the flow chart for sewing needle selection control; 
       FIG. 7  is an example of screen display of sewing needle determination result; and 
       FIG. 8  shows data contained in a table storing sewing needle thread type mapping data in an alternative illustrative aspect. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   An embodiment of the present invention will be described hereinafter with reference to the drawings. 
   As shown in  FIG. 1 , a multi-needle sewing machine M is constructed by a foot  1  supporting the entire sewing machine, a pillar  2  standing on the rear end of the foot  1 , and an arm  3  extending to the front from the upper portion of the pillar  2 . 
   A movable case  4  is provided on the upper side of the foot  1 . A frame mounting base  5  is provided on the front side of the movable case  4 . A lateral drive mechanism equipped with an x-direction drive motor  33  (refer to  FIG. 2 ) is provided inside the movable case  4 . The frame mounting base  5  is laterally driven by the x-direction drive motor  33  (refer to  FIG. 2 ). A longitudinal drive mechanism equipped with a y-direction drive motor  34  (refer to  FIG. 2 ) is provided inside the foot  1 . The movable case  4  is longitudinally driven by the y-direction drive motor  34 . An embroidery frame  6  retaining a workpiece cloth to be sewn in a stretched manner is mounted on the frame mounting base  5 . The frame mounting base  5  is moved in the lateral direction by the lateral drive mechanism and the movable case  4  is moved in the longitudinal direction by the longitudinal drive mechanism. Thus, the workpiece cloth mounted on the frame mounting frame  5  via the embroidery frame  6  is fed in longitudinal and lateral directions. 
   A needle bar case  7  mounted with a synthetic resin cover is attached on the front side of the arm  3 . A cylindrical bed  8  extending to the underside of the needle bar case  7  which is disposed in the front side of the multi-needle sewing machine is provided in the pillar  2 . In the needle bar case  7 , six needle bars  9  are stored in a single lateral row. A sewing needle  10  is attached on the lower end of each needle bar  9 . Also, six thread take-ups  11  in a single lateral row are mounted in the needle bar case  7 . Each thread take-up  11  has a corresponding needle bar  9 . A thread tension frame  12  made of synthetic resin and which is slightly inclined in the upper rear direction is fixed on the upper end of the needle bar case  7 . Six thread tension regulators  13  are provided on the thread tension frame  12 . Each thread tension regulator  13  is associated with needle thread T used by each sewing needle  10 . 
   Six spool pin bases  14  are provided on the upper side of the arm  3 . Thread spools  15  serving as thread supply are attached on such spool pin bases  14 . The needle thread T drawn from each thread spool  15  is hooked on the corresponding thread tension regulator  13 , thread take-up  11 , and the like and supplied to the sewing needle  10 . 
   A needle bar switching mechanism (not shown) having a needle bar switching motor  32  (refer to  FIG. 2 ) is provided inside the arm  3 . The needle bar case  7  is moved in the lateral direction integrally with the thread tension frame  12  by the needle bar switching mechanism. Thus, one of the six needle bars  9  and the thread take-ups  11  are selectively switched to the active position. When the sewing machine motor  31  (refer to  FIG. 2 ) is driven, the sewing needle  10  is vertically driven via the needle bar  9  and the thread take-up  11 . The sewing needle  10 , in cooperation with a rotary hook (not shown) provided inside the cylinder bed  8 , forms stitches on the workpiece cloth set on the upper side of the cylinder bed  8  by the needle thread T and a bobbin thread. An operation panel  16  of a touch-panel type is provided on the right side of the arm  3 . The operation panel  16  is mounted on the arm  3  via a connection arm  17 . The operation panel  16  is slidable in the axial direction of the connection arm  17 , and can also be folded toward the rear end of the arm  3  along with the connection arm  17 . 
   Next, an electronic configuration of the multi-needle sewing machine M will be described. 
   As shown in  FIG. 2 , a sewing machine control device  20  is configured by a microcomputer including a CPU  21 , a ROM  22 , and a RAM  23 ; an input interface  25 ; an output interface  26 ; and the operation panel  16 . The input and output interfaces  25  and  26  are connected to the microcomputer via a bus  24  such as a data bus. 
   The operation panel  16  is connected to the input interface  25 . The operation panel  16 , drive circuits  27 ,  28 ,  29  and  30  respectively provided for the sewing machine motor  31 , needle bar switching motor  32 , x-direction driving motor  33 , and the y-direction drive motor  34  are connected to the output interface  26 . 
   A control program, a sewing needle selection control program, sewing data, and the like are stored in the ROM  22 . The control program controls the multi-needle sewing machine M. The sewing needle selection control program, as shown in  FIGS. 6A and 6B , selects a sewing needle  10  set with a needle thread T similar to the thread color specified by a later described thread color data from the plurality of sewing needles  10  set with needle threads T of different thread colors. The sewing data is provided for performing embroidery sewing. The sewing data stored in the ROM  22 , as shown in  FIG. 3 , includes the thread color data indicating the thread color of needle thread T to be used for the sewing process and the needle drop point data indicating the needle drop point for the sewing process. The thread color data and the needle drop point data are set in each sewing area (A 1  to A 7  in  FIG. 3 ) within a sewing pattern. The sewing area contains one or more consecutive stitches formed by the same color of needle thread T. The sewing data is used by the multi-needle sewing machine M by being loaded into the RAM  23  upon sewing process or pattern editing process. The sewing data may be stored not only in the built-in ROM  22  storage but also be in an external storage medium such as a flexible disk or a ROM cartridge and loaded into the RAM  23  from such external storage medium. 
   As shown  FIG.4 , a sewing needle-thread color mapping data specifying a correspondence between the six sewing needles  10  and the thread colors of the needle threads T respectively set to each sewing needle  10  is stored in the RAM  23 . Also, as shown in  FIG. 5 , a table containing preset RGB values for each thread color is stored in the RAM  23 . The RGB value is used to identify a thread color. 
   The sewing needle-thread color mapping data can be set by user input from the operation panel  16 . Upon initial use of the multi-needle sewing machine M, the sewing needle-thread color mapping data is stored in the RAM  23  by the user&#39;s input of the thread color of the needle thread T set on each sewing needle  10 . Thereafter, in case the user changes the needle thread T set for each sewing needle  10 , such change can be updated to the sewing needle-thread color mapping data by user input via the operation panel  16 . Also, the sewing needle-thread color mapping data stored in the RAM  23  may be stored in a nonvolatile memory such as an EEPROM (not shown) provided in the multi-needle sewing machine. In such case, the sewing needle-thread color mapping data can be used by loading the same to the RAM  23  upon turning on the power supply to restart the embroidery sewing process. 
   The operation panel  16  is controlled by the microcomputer. As shown in  FIG. 7 , a selection result screen is displayed on a display portion  16   a  of the operation panel  16 . When replacing the thread color, in case a sewing needle  10  set with a needle thread T that matches with the thread color specified by the thread color data does not exist, a sewing needle number of the sewing needle  10  set with needle thread T having a thread color which is similar to the thread color specified in the thread color data is displayed on the selection result screen. Also, whether to use the selected sewing needle  10  or to replace the thread spool  15  can be selected by a touch operation of the operation panel  16 . 
   In case the user chooses to use the selected sewing needle  10 , the sewing machine control device  20  activates the needle bar switching motor  32  by the drive circuit  28  and switches the needle bar  9  set with the selected sewing needle  10  to the active position. Then the sewing machine motor  31  is driven by the drive circuit  27  and the sewing process is executed by the selected sewing needle  10 . On the other hand, in case the user chooses to replace the thread spool  15  and selects one of the sewing needles  10  identified by the sewing needle numbers 1 to 6, the sewing machine control device  20  switches the needle bar  9  set with the selected sewing needle  10  to the active position. Then by driving the sewing machine motor  31  by the drive circuit  27 , sewing is executed by the selected sewing needle  10 . 
   Next, a flow chart depicting the sewing needle selection control executed by the sewing machine control device  20  will be described based on  FIGS. 6A and 6B . The symbols Si (i=1,2,3, . . . ) in the figure indicate each step number. 
   When the user sets the embroidery frame  6  holding the workpiece cloth to the frame mounting base  5  and starts the sewing operation by the multi-sewing needle sewing machine M, the sewing machine control device  20  loads the sewing data from the RAM  23  (S 1 ). Then, the process proceeds to step S 2  and determination is made whether the loaded sewing data is a thread color data or not. In case the loaded sewing data is a thread color data, the sewing machine control device  20  makes a yes decision and proceeds to step S 3  where the sewing needle-thread color mapping data is loaded from the RAM  23 . Next, the sewing machine control device  20  proceeds to step S 4 . In step S 4 , the similarity D of the thread color specified in the thread color data and thread color of needle thread T set to each sewing needle  10  is calculated based on the RGB value of the thread color data and the thread color-sewing needle mapping data. At this point, the RGB value of the thread color specified in the thread color data and the sewing needle-thread color mapping data can be obtained by referring the table shown in  FIG. 5 . The sewing machine control device  20  calculates the similarity D from the following formula by using the RGB value (R 1 , G 1 , B 1 ) of the thread color data in the sewing data and the RGB value (R 2 , G 2 , B 2 ) of the thread color of the thread color-sewing needle mapping data.
 
 D =( R 2 −R 1) 2 +( G 2 −G 1) 2 +( B 2 −B 1) 2  
 
It needs to be noted that the smaller the value of similarity D, the higher the similarity of the two colors.
 
   The sewing machine control device  20 , after calculating the similarity D, proceeds to step S 5 . In step S 5 , a judgment is made whether the calculated similarity D is zero or not; that is, whether or not the sewing needle  10  is set with needle thread T having a thread color matching the thread color specified in the thread color data or not. In case the similarity D calculated is 0, the sewing machine control device  20 , after making a Yes decision, proceeds to step S 10  where the needle bar switching control for switching the needle bar  9  set with the relevant sewing needle  10  is executed, and the control is returned. 
   In the above mentioned step S 2 , in case the loaded sewing data is not a thread color data, the sewing machine control device  20  makes a No decision and proceeds to step S 7  where a judgment is made whether the loaded sewing data is a needle drop point data or not. In case the loaded sewing data is a needle drop point data, the sewing machine control device  20 , after making a Yes decision, moves on to step S 8  where the sewing operation by the sewing needle  10  is executed and the process is returned. On the other hand, in the above step S 7 , in case the loaded sewing data is not a needle drop point data, that is, in case of data indicating a stop or a termination of sewing operation, the sewing machine control device  20 , after making a No decision, proceeds to step S 9 . In step  9 , a process in accordance with the given data is executed and the control is returned. 
   In the above step S 5 , in case the similarity D calculated by the aforementioned formula is not 0; that is, in case a sewing needle  10  set with a needle thread T matching the thread color specified by the thread color data is not detected, the sewing machine control device  20  makes a No decision and proceeds to step S 6 . In step S 6 , a judgment is made whether the loading of the thread color-sewing needle mapping data is completed or not. In case loading is not completed, the sewing machine control device  20  makes a No decision and proceeds to step S 3 . Thereafter, the process in steps S 3  to S 6  are executed until the similarity D in step S 5  amounts to 0, or loading of the sewing needle-thread color mapping data for each sewing needle  10  in step S 6  is completed. 
   Then, in the above step S 6 , in case the loading of the sewing needle-thread color mapping data for all the sewing needles  10  is completed; that is, in case the sewing needle  10  set with the needle thread T matching the thread color specified in the thread color data is not detected, the sewing machine control device  20  makes a Yes decision. Then, the process proceeds to step S 11  (refer to  FIG. 6B ) and stops the sewing operation of the multi-needle sewing machine M. 
   Next, the sewing machine control device  20  proceeds to step S 12  and judges the sewing needles  10  having the lowest similarity D among the six sewing needles  10 . The sewing needle  10  set with the thread color which is most similar to the thread color specified in the thread color data is selected as the sewing needle  10  to be used for the sewing process. Then the sewing machine control device  20  proceeds to step S 13  and as shown in  FIG.7 , displays the selection result to the display portion  16   a  of the operation panel  16 . Next, the sewing machine control device  20  proceeds to step S 14  and judges whether the selected sewing needle  10  has been chosen or not; that is, whether the sewing needle  10  set with the similar thread color has been chosen or not. In case the user chooses the selected sewing needle  10  by touching the screen displayed on the display portion  16   a , the relevant sewing needle  10  is determined as the sewing needle  10  to be used for the sewing process. Then the sewing machine control device  20 , after making a Yes decision, proceeds to step S 15 . In step S 15 , the needle bar switching control is executed in order to perform the sewing operation with the selected sewing needle  10  and the control is returned. 
   On the other hand, in the above step S 14 , in case “replace thread spool” is selected on the screen displayed on the display portion  16   a , the sewing machine control device  20  makes a No decision and proceeds to step S 16  where the sewing needle number of the selected sewing needle  10  is identified. Then, in case the sewing needle  10  to be replaced has been selected, the sewing machine control device  20 , after making a Yes decision, proceeds to step S 17  and executes the needle bar switching control. In the needle bar switching control, the sewing machine control device  20  switches the needle bar  9  set with the relevant sewing needle  10  to the active position in order to enable the user to perform the sewing operation with the sewing needle  10  set with the new needle thread T drawn from the replaced thread spool  15 . Also, upon processing step S 17 , among the sewing needle-thread color mapping data stored in the RAM  23 , the sewing machine control device  20  updates the thread color corresponding to the replaced sewing needle  10  with the thread color of the newly set needle thread T. 
   In the above step S 16 , in case the sewing needle  10  to be replaced is not selected, the sewing machine control device  20  makes a No decision. Then the sewing machine control device  20  displays a warning message to the display portion  16   a  indicating that the sewing needle  10  to be replaced has not been selected. Then, the process is returned to step S 14 . 
   According to the present embodiment described above, among the plurality of sewing needles  10  set with needle threads T of different thread colors, the sewing needle  10  set with the needle thread T similar to the thread color specified by the thread color data is determined as the sewing needle  10  to be used for the sewing process. As a result, sewing can be performed with the similar thread color without replacement of the needle thread T, thereby reducing the user&#39;s burden of having to replace the thread spool. 
   In case the sewing needle  10  set with the needle thread T matching the thread color specified in the thread color data is detected, the detected sewing needle  10  can be used for the sewing process. On the other hand, in case the sewing needle  10  set with the matching thread color is not detected, the sewing operation of the multi-needle sewing machine M is stopped and the sewing needle  10  set with the needle thread T having the similar thread color can be used for the sewing process. 
   Furthermore, the selected sewing needle  10  is displayed to the operation panel  16  enabling the user to decide whether to use the selected sewing needle  10  for the sewing process or not via the operation panel  16 . Thus, the sewing needle  10  set with the needle thread T having the similar thread color need not be searched by the user, thereby reducing the user&#39;s burden. 
   Also, by allowing the user him/herself to decide whether to use the similar thread or replace the thread spool  15 , the freedom of thread selection is increased. Additionally, according to the present embodiment, the frequency of thread spool replacement can be reduced as compared to what has been conventionally required. 
   Yet, furthermore, the sewing operation by the selected sewing needle  10  can be easily restarted by the touch operation of the operation panel  16 , thereby reducing the user&#39;s burden. 
   Also, since the detection of consistency between the thread color specified in the thread color data and the thread color of the needle thread T set to each sewing needle  10 , as well as the selection of similarity is performed based on the RGB value that specifies the thread color. Therefore a complex construction for determining the thread color is not required. This allows for a provision of a simply configured sewing machine control device  20 , which also yields cost advantage. 
   The present invention is not limited to the embodiment described above and illustrated in the drawings but can be transformed or expanded as follows. 
   Alternative to the sewing needle-thread color mapping data, as shown in  FIG. 8 , sewing needle-thread type mapping data may be used which is capable of specifying the correspondence between the six sewing needles  10  and the type of needle thread T set to each sewing needle  10 . Also, thread specification data capable of specifying the thread type can be used instead of the thread color data. The type of needle thread T in this context includes data such as the thread color, manufacturer (corresponding to thread supplier), thread thickness, and thread material or the like. In this case, the sewing needle-thread type mapping data is stored in a sewing needle-thread type storage medium. According to such construction, even if a plurality of sewing needles is set with a thread color having the highest similarity with the thread color specified by the thread specification data, the similarity can be further determined by other data such as the manufacturer, thread thickness and thread material. 
   Thus, the similarity D can be determined based on not only by the thread color but also by the thread thickness, manufacturer and thread material, thereby further improving the accuracy in sewing needle selection. Similarity D can also be determined based on a thread number assigned by the manufacturer. 
   In the above described embodiment, the calculation process of similarity D based on the thread color data in the sewing data and sewing needle-thread color mapping data; and the detection process that determines whether the sewing needle  10  set with the thread having the matching thread color exists or not is performed upon every execution of the sewing process by each sewing needle  10 . Alternatively, such calculation and detection process can be performed in prior to the sewing process. For instance, in prior to the start of sewing operation by the multi-needle sewing machine M, a predetermined number (for example, the first six colors) of thread color data can be loaded from the sewing data. Then, the aforementioned calculation process of similarity D and the detection process of the sewing needle  10  can be performed for such predetermined number of thread color data. 
   Furthermore, the above described determination process in steps S 14  and thread spool replacement process in step S 16  can be performed in prior to the start of the sewing process. 
   In the above described embodiment, upon calculating similarity D, the thread color specified by the thread color data and the thread color in the sewing needle-thread color mapping data are associated with an RGB value by referring  FIG. 5 . Alternatively, the thread color specified in the thread color data and the thread color in the sewing needle-thread color mapping data can be stored in the form of RGB value in advance. 
   In the above described embodiment, the operation panel  16  of a touch-panel type is provided which integrally assumes the functions of the informing unit and the operation unit. Alternatively, a display serving as the informing unit and operation keys serving as the operation unit can be provided separately. 
   Also, the informing unit may be provided as a light-emitting device composed of a plurality of light-emitting diodes or a buzzer, or the like. In such case, the sewing needle  10  to be switched can be informed to the user by changing the color of the light emitted by the light-emitting device or by changing the sound of the buzzer. 
   The foregoing description and drawings are merely illustrative of the principles of the present invention and are not to be construed in a limited sense. Various changes and modifications will become apparent to those of ordinary skill in the art. All such changes and modifications are seen to fall within the scope of the invention as defined by the appended claims.