Sewing Machine

This application claims priority from Japanese Patent Application No. 2024-101085 filed on Jun. 24, 2024. The entire content of the priority application is incorporated herein by reference.

A sewing machine including a movement detector for detecting movement of a sewing workpiece is known.

A sewing machine adjusts stitch lengths based on a detection result of a movement detector that detects movement of a fabric. The movement detector includes a light receiving element for detecting light to detect the movement of the fabric, a main body having the light receiving element therein and attachable to and detachable from a presser bar of the sewing machine, and a presser support having a fabric presser that contacts the fabric and attachable to and detachable from the main body. The main body includes a bottom surface having a window through which light passes. In a state where the presser support is attached to the main body, the fabric presser is located below the bottom surface of the main body. The fabric movement detector outputs a detection result corresponding to the movement amount of the fabric to the sewing machine.

In known sewing machines, the convenience of a user when sewing is performed using a movement detector has not been sufficiently considered.

In view of the foregoing, an example of an object of this disclosure is to provide a sewing machine that contributes to improving the convenience of a user when sewing is performed using a movement detector.

According to one aspect, this specification discloses a sewing machine including a bed including a bed surface, a needle bar, a presser bar, a projector, and a controller. A movement detector is attachable to the presser bar. The controller is configured to perform a sewing control of, in a state where the movement detector is attached to the presser bar, controlling an up-down reciprocating speed of the needle bar based on a signal output from the movement detector. The signal corresponds to a movement amount of a sewing workpiece located in a detection region. The sewing control contributes to making the stitch length constant by controlling the speed of the needle bar based on the movement amount of the sewing workpiece. The controller is configured to perform a projection of, during performing the sewing control, controlling the projector to project an image toward the bed surface. The projection contributes to improving the convenience of the user in a case where sewing is performed using the movement detector, compared with a case where an image is not projected.

An embodiment of the present disclosure will be described with reference to the drawings. The upper-lower direction, the left-lower direction, the right-upper direction, the left-upper direction, and the right-lower direction inare the upper-lower direction, the leftward direction, the rightward direction, the rearward direction, and the forward direction of a sewing machine, respectively. A longitudinal direction Dof a bedand an armis the left-right direction of the sewing machine. A short direction Dof the bedand the armin a horizontal plane is the front-rear direction of the sewing machine. In the sewing machine, the side on which a pillaris disposed is the right side. The extending direction of the pillaris the upper-lower direction of the sewing machine. A direction that is perpendicular to the upper-lower direction and that is from a needle bartoward a presser baris a rearward direction, and is defined as a forward feed direction F. The direction opposite to the forward feed direction F is forward and is defined as a reverse feed direction B. The forward feed direction F and the reverse feed direction B are directions along the short direction D.

As shown in, the sewing machineincludes the bed, the pillar, and the arm. The pillarextends in the upper-lower direction. The bedhas a bed surfaceand extends leftward from the lower end of the pillar. The armextends leftward from the upper end of the pillarin parallel with the bedabove the bed. The armhas a headat the left end of the arm.

The bed surfaceextends horizontally. The bed surfaceincludes a needle plateextending horizontally. As shown in, the needle plateis formed with a needle holethrough which a sewing needleis inserted. The bedincludes a feed mechanismshown inand a hook mechanism (not shown), for example, below the needle plate. The feed mechanismincludes a feed dog. The feed mechanismdrives the feed dogto move the sewing workpiece in the forward feed direction For the reverse feed direction B by a particular movement amount. The forward feed direction F corresponds to the direction in which the sewing machineis disposed with respect to the user. The hook mechanism includes a hook. The hook mechanism drives the hook to entangle an upper thread with a lower thread.

As shown in, a liquid crystal display (LCD)and a touch screenthat are long in the upper-lower direction are provided on the front side of the pillar. The LCDdisplays messages for sewing work, for example. The touch screenis disposed on the front surface of the LCD. When the user selects an item displayed on the LCDwith a pointing body such as a finger or a dedicated stylus pen described later, the touch screendetects the selected position. The user inputs various instructions to the sewing machinevia the touch screen.

A plurality of switches including a start-stop switchare provided on the front surface of the arm. The start-stop switchis a switch for instructing the start and stop of a sewing operation. The start-stop switchincludes a green LED and a red LED (an example of a lamp), and notifies a sewing state of the sewing machineby a lighting state of the LEDs. A sewing machine cover configured to open and close (not shown) is provided on the upper portion of the arm. In, the sewing machine cover of the armis not shown. A thread storage portionis provided on an upper surfaceof the armthat is exposed in a state where the sewing machine cover is opened. The thread storage portionis a recess that is recessed downward and stores a thread spool T around which an upper thread is wound. A thread spool pinextends leftward from the right inner wall surface of the thread storage portion. The thread spool T is mounted on the sewing machineby inserting the thread spool pininto an insertion hole of the thread spool T.

The headincludes a needle bar mechanism and a presser foot mechanism (not shown) inside the head. The needle bar mechanism includes the needle barextending in the upper-lower direction, and reciprocates the needle barin the upper-lower direction. A lower end portion of the needle barprotrudes downward from the lower end of the head. A sewing needleis detachably attached to the lower end of the needle bar. The sewing needleattached to the needle barreciprocates in the upper-lower direction. The upper thread inserted through the sewing needleis entangled with the lower thread by the hook, and forms stitches on the sewing workpiece. The presser foot mechanism includes the presser barextending in the upper-lower direction, and reciprocates the presser barin the upper-lower direction. A lower end portion of the presser barprotrudes downward from the lower end of the head.

The movement detectoris used when the user performs sewing while manually moving a sewing workpiece C placed on the bed surfacewithout using the feed dog. The movement detectoroutputs a signal corresponding to the amount of movement (movement amount) of the sewing workpiece C. The movement detectordetects the movement amount of the sewing workpiece C disposed on the bedbelow the presser bar, and outputs the movement amount to the sewing machine. The sewing machinecontrols the driving of the sewing machine motorbased on the movement amount per unit time of the sewing workpiece C, that is, movement speed, thereby adjusting (regulating) the length of the stitches formed on the sewing workpiece C. The presser footis attachable to and detachable from the movement detector. The presser footis disposed above the upper surface of the sewing workpiece C by a particular distance, and is moved to contact the sewing workpiece C, thereby preventing the sewing workpiece C placed on the bed surfacefrom lifting.

As shown in, the movement detectorincludes a housing, a sensor, a cable, and a mount body (mount bracket). The housinghas a rectangular parallelepiped shape that is longer in the front-rear direction than in the left-right direction. The housingis attachable to and detachable from the presser barof the sewing machine. The housingaccommodates the sensor.

The sensoris located above an openingformed in a lower surfaceof the housing. As shown in, the sensorincludes a light emitting elementand a light receiving element. The light emitting elementand the light receiving elementare located above the opening. The light emitting elementemits light toward the sewing workpiece C to detect the movement amount of the sewing workpiece C. The light emitting elementis, for example, an infrared light emitting diode that emits infrared light. In a state where the movement detectoris attached to the presser barof the sewing machine, the light emitted by the light emitting elementis emitted downward. The emitted light passes through the openingand reaches the sewing workpiece C, and is reflected. The light reflected by the sewing workpiece C passes through the opening. The light receiving elementis an element for detecting the light reflected by the sewing workpiece C located in a detection region M, and detects the light reflected by the sewing workpiece C and converts the light into an electrical signal. The detection region M is a circular region in a plan view and is located below the opening. The diameter of the detection region M is, for example, 1 mm. The detection region M is on a guideline extending through a needle position NP and extending in the short direction D. The detection region M is located rearward of the needle position NP and the presser bar. The light receiving elementis, for example, an infrared imaging element that detects infrared light. The light emitting elementperiodically emits light toward the sewing workpiece C, and the sensordetects the movement amount of the sewing workpiece C per unit time.

The cableextends upward from rearward of the upper surface of the housing. The cableis detachably connected to a connector (not shown) provided at the back surface of the arm. The movement detectoroutputs the movement amount of the sewing workpiece C per unit time to the sewing machinevia the cable. The mount bodyextends upward from the upper surface of the housing. The mount bodyis detachably attached to the presser bar. With this configuration, the movement detectoris detachably attached to the lower end of the presser bar.

As shown in, the headfurther includes a projectorinside the head. The projectoris configured to project an image onto the bed surface. The projectorincludes a generatorshown in, as well as a light guide and a lens (not shown). The generatorincludes a reflective display device, a light source, and a mirror and a prism (not shown). The light sourceis, for example, an LED lamp of RGB. The generatorgenerates image light constituting an image by projecting light from the light sourcetoward an image displayed on the reflective display device. The generatoremits the generated image light toward the light guide. The generatormay operate by using a method other than the reflective display method, such as methods adopted by transmissive display devices, laser light sources, or self-luminous deposition devices. The light guide guides the image light generated by the generatorto the lens. The image light guided by the light guide is emitted through the lens toward the bed. The lens is an eccentric optics projection lens. An eccentric optical system is an optical system in which the lenses, mirrors, and other components that make up the optical system are not on the same straight line. The number, type, and arrangement of the lenses and mirrors that make up the eccentric optical system may be set as appropriate.

As shown in, the projectoris configured to project an image on a projection region R. The projection region R of the projectoris a rectangular region in a plan view. Two sides of the projection region R extending in the short direction Dare long sides and two sides of the projection region R extending in the longitudinal direction Dare short sides. In the short direction D, the projection region R is a region on the bed surfacesurrounding the presser footof the movement detectorattached to the presser barand includes the needle position NP located below the needle bar. The projection region R is a region surrounding the movement detectorthat is attached to the presser bar. Additionally, the projection region R includes a range of the needle plateon the bed.

Since the projectoris disposed leftward of the needle bar, when the projectoris driven, a shadow of the needle baris formed rightward of the needle bardue to the image light projected by the projector. In other words, the shadow formed by the image light projected by the projectoris not formed forward of the needle bar.

The operation of the sewing machinehaving the above-described configuration when the sewing workpiece is conveyed by the feed dogwill be briefly described. When the sewing machinedetects that the start-stop switchhas been pressed, the hook mechanism, the feed mechanism, the needle bar mechanism, and the presser foot mechanism are driven synchronously. With this operation, the sewing needleattached to the needle barforms stitches in the sewing workpiece C placed on the bed surface.

The electrical configuration of the sewing machinewill be described with reference to. The controllerof the sewing machineincludes a CPU, a ROM, a RAM, a memory, and an input-output interface. The CPUis connected to the ROM, the RAM, the memory, and the input-output interfacevia a bus.

The CPUperforms main control of the sewing machineand performs various calculation and processing related to sewing in accordance with various programs stored in the ROM. The ROMincludes a plurality of storage areas, including a program storage area (not shown). The program storage area stores various programs for operating the sewing machine, including a program for performing a main process described later.

The RAMincludes a storage area that stores the results of calculation and processing performed by the CPU. For example, the memorystores various parameters used by the sewing machineto perform various processing. The memorystores data for a tableshown in. The tableincludes settings for a stitch regulating function, sewing modes, sewing states when the movement detectoris attached to the presser bar, and lighting states of the start-stop switchaccording to movement states and projection modes of icons included in the image projected by the projector.

The stitch regulating function is a function of making the stitch length constant by moving the needle barin synchronization with the moving speed of the sewing workpiece C, and the setting of the stitch regulating function is ON or OFF. The sewing mode defines conditions for driving the needle barbased on a signal output from the movement detector. When the power supply to the movement detectoris ON, the sewing machineof this embodiment drives the needle barin the sewing mode selected from an intermittent mode, a basting stitch mode, and a continuous mode, based on the signal output from the movement detector. The intermittent mode and the basting stitch mode are modes in which, when the movement amount of the sewing workpiece C detected by the movement detectoris 0, the reciprocal movement of the needle barin the upper-lower direction stops, and when the movement amount is greater than 0, the needle barreciprocates in the upper-lower direction at a speed corresponding to the movement amount. The stitch length in the basting stitch mode is greater than the stitch length in the intermittent mode. The continuous mode is a mode in which, when the movement amount of the sewing workpiece C detected by the movement detectoris 0, the needle barreciprocates in the upper-lower direction at a particular speed, and when the movement amount is greater than 0, the needle barreciprocates in the upper-lower direction at a speed corresponding to the movement amount. The sewing machineof this embodiment drives the needle barin a free motion mode when the power supply to the movement detectoris OFF. In the free motion mode, the movement detectordoes not output a signal and the needle barreciprocates in the upper-lower direction at a constant speed, regardless of the movement state.

The sewing state includes “sewing in progress” and “waiting”. The “sewing in progress” is a state in which the start-stop switchis pressed and the needle baris movable reciprocally in the upper-lower direction based on the signal output from the movement detector. The “waiting” is a state in which the needle barstops reciprocating in the upper-lower direction and is waiting for the start-stop switchto be pressed, regardless of a signal output from the movement detector. The movement state indicates whether it is determined that the sewing workpiece C is moving or stopped based on the signal output from the movement detector.

The lighting state of the start-stop switchis one of “steady green”, “blinking green”, and “steady red”. The icon is a figure that indicates an operating state of the sewing machine. In this embodiment, the icon is projected in a projection mode according to the operating state of the sewing machine. When the setting of the stitch regulating function is ON, the projection mode of the icon is the same as the lighting state of the start-stop switch. When the setting of the stitch regulating function is OFF, the projection mode of icon is OFF, that is, the icon is not included in the projection image.

As shown in, the memoryof this embodiment further stores a coordinate system of the projector(hereinafter also referred to as “projection coordinate system”) and a coordinate system of the entire space (hereinafter also referred to as “world coordinate system”). These coordinate systems are associated with each other in advance by parameters stored in the memory. Thus, the sewing machineis configured to identify coordinates in the projection coordinate system based on the world coordinates of the planned projection position of the image, and identify coordinates in the world coordinate system based on image data. According to this embodiment, the image is a multiple-color image. However, the image may be a single-color image, or the color of the image may be adjustable according to the color and pattern of the sewing workpiece C.

Drive circuits,,,andof a controller (processor), the touch screen, the start-stop switch, the light sourceof the projector, and the light emitting elementand the light receiving elementof the sensorof the movement detectorare connected to the input-output interface. The light sourceturns on according to a control signal output from the CPUand projects the image displayed on the reflective display deviceonto the sewing workpiece C placed on the bed.

The drive circuitis connected to the sewing machine motor. The drive circuitdrives the sewing machine motoraccording to the control signal output from the CPU. When the sewing machine motoris driven, the needle bar mechanism is driven via the main drive shaftof the sewing machine, and the needle barreciprocates in the upper-lower direction. A feed-amount adjustment motoris connected to the drive circuit. The feed-amount adjustment motorrotates its output shaft to adjust the feed amount of the sewing workpiece C in the front-rear direction by the feed mechanism. The drive circuitdrives a presser motoraccording to a control signal output from the CPU. When the presser motoris driven, the presser barmoves in the upper-lower direction independently of the driving of the main drive shaftof the sewing machine. The drive circuitdrives the LCDaccording to a control signal output from the CPUto display an image on the LCD. The drive circuitdrives the reflective display deviceof the generatorof the projectoraccording to a control signal output from the CPUto display an image on the reflective display device.

The main process of the sewing machinewill be described with reference to. In the main process, the needle barreciprocates in the upper-lower direction based on the detection result of the movement detector, in response to an instruction from a user, to thereby perform sewing on the sewing workpiece C. The main process starts when the user inputs an instruction to display a screen Gshown in. In response to detecting an instruction to display the screen G, the controllerreads out the program for performing the main process stored in the program storage area of the ROMto the RAM. The controllerperforms the following steps according to the instructions contained in the program read out to the RAM. The various parameters used to perform the main process are stored in the memory. Various data acquired in the course of the main process are stored in the RAMas appropriate. In the following description, the various image data to be processed by the controlleris simply referred to as “image.” “Step” is abbreviated as “S.”

Based on the signal output from the movement detector, the controllerdetermines whether the stitch regulating function, which makes the stitch length constant by moving the needle barin synchronization with the movement speed of the sewing workpiece C, is ON (S). In response to determining that the stitch regulating function is not ON (S: NO), the controllerdrives the sewing machinein free motion mode, in which sewing is performed while moving the needle barreciprocally in the upper-lower direction at a constant cycle (S) and turns off the icon, that is, the icon is not included in the image projected by the projector(S). After the driving in free motion mode is finished, the controllerstops driving the projector(S) and ends the main process.

In response to determining that the stitch regulating function of the movement detectoris ON (S: YES), the controllerdisplays, on the LCD, a screen used when the stitch regulating function of the movement detectoris ON (S). In S, the controllerdisplays the screen Gshown inon the LCD. The screen Gincludes key images J, J, J, J, Jand J. The key image Jis selected when the user inputs an instruction to display a projection condition setting screen. The key image Jis selected when the user inputs instruction to display a guideline setting screen. The key image Jis selected when the user inputs an instruction to display a setting screen for a guide pattern indicating the position of the sensor.

The key images J, Jand Jare selected when the user inputs an instruction to select the sewing mode. The key image Jis selected when the user inputs an instruction to select the intermittent mode. The key image Jis selected when the user inputs an instruction to select the basting stitch mode. The key image Jis selected when the user inputs an instruction to select the continuous mode.

As shown in, the controllerdrives the presser motorto lower the presser barto a position where the presser footof the movement detectorcontacts the sewing workpiece C and acquires the thickness of the sewing workpiece C based on the position where the presser footcontacts the sewing workpiece C (S). As shown in, after acquiring the thickness of the sewing workpiece C, the controllerdrives the presser motorto dispose the presser footat a particular distance above the position where the presser footcontacts the sewing workpiece C. The particular distance is set to a value of 1 to 4 mm, for example.

As shown in, the controlleracquires an image generated by an image output process (S). As shown in, in the image output process, the controlleracquires the color of a guide pattern (S). The color of the guideline is set by the user with reference to a screen Gshown in. The screen Gis displayed on the LCDwhen the key image Jis selected on the screen Gin. The screen Gincludes a toggle switch image K, fields K, Kand K, and a sub-screen K. The toggle switch image Kinstructs the user to set whether to include the guide pattern in the image. In, the switch is set to ON, which means that it is set that the guide pattern is included in the image. Note that, in, a label “Guideline” shown leftward of the toggle switch image Kmeans “guide pattern” in this specification.

The field Kis a field for selecting the type of the guide pattern to be included in the image. The controllerof this embodiment selects the type of the guide pattern from among six types of guide patterns as the guide pattern to be included in the image in addition to a first guideline and an icon described later. A first guide pattern includes a second guideline that extends in the short direction Dand indicates the position of the detection region M in the longitudinal direction D. The second guideline is a guideline passing through the needle position NP and the detection region M and extends in the short direction D. A second guide pattern is grid lines at particular intervals. A third guide pattern is two guidelines that form a particular angle at the needle position NP. A fourth guide pattern includes a cross formed by a needle bar guideline and the second guideline crossing at the needle position NP as the intersection, and circles centered at the intersection of the cross. The needle bar guideline is a guideline extending in the longitudinal direction Dthrough the needle position NP. A fifth guide pattern includes a cross formed by the needle bar guideline and the second guideline crossing at the needle position NP, and auxiliary guidelines located at particular distances from the cross. A sixth guide pattern is selected when no guide pattern is to be included in addition to the first guideline and the icon described later.

The sub-screen Kincludes a field Kand a key image K. The field Kdisplays color candidates for the guide pattern. The color candidates of this embodiment include sixteen different colors. The key image Kis selected when the user enters an instruction to close the sub-screen K. After the user has selected a color from the candidates displayed in the field K, the user selects the key image Kto set the color of the guide pattern.

The controlleracquires a background color of the image (S). The background color of the image is set by the user by using a screen Gshown in. The screen Gis displayed when the key image Jis selected on the screen Gshown in. The screen Gincludes a field Land the sub-screen Ksimilar to that show in. The field Lis a field for setting the background color of the image. The user selects the field Land selects a color from candidates displayed in the field K. Then, the user selects the key image Kto set the background color of the image. The background color of the image may be set to a color different from the color of the guide pattern acquired in S.

The controlleracquires the type of the guide pattern (S). The type of the guide pattern is set by the user by using the field Kon the screen Gshown in. The user selects a guide pattern from six candidates displayed in the field K, and sets the type of the guide pattern.

As shown in, the controllergenerates an image Fin a background color based on the background color acquired in S(S). In, the length of the image Fin the left-right direction corresponds to the length in the longitudinal direction D, and the length of the image Fin the upper-lower direction corresponds to the length in the short direction D. The controllergenerates an image representing a rectangle corresponding to the projection region R filled with the background color. In the image F, a dotted line represents a mask W, which indicates the range of the movement detectorin the image F.

Based on the color of the guide pattern acquired in Sand the type of the guide pattern acquired in S, the controlleradds the type of the guide pattern acquired in Sin the color acquired in Sto the image generated in S, which is a rectangle filled with the background color (S). In a case where the type of the guide pattern is the fifth guide pattern, the controllergenerates an image Fshown in. The image Fincludes a second guideline N, a needle bar guideline N, and auxiliary guidelines N, N, Nand N. The second guideline Nindicates the position of the detection region M in the longitudinal direction D, and the detection region M is located on the second guideline N. The auxiliary guideline Nextends in the short direction Dat a particular distance leftward of the second guideline N. The auxiliary guideline Nextends in the short direction Dat a particular distance rightward of the second guideline N. The second guideline Nand the auxiliary guidelines Nand Neach extend from the front end to the rear end of the image F. The auxiliary guideline Nextends in the longitudinal direction Dat a particular distance forward of the needle bar guideline N. The auxiliary guideline Nextends in the longitudinal direction Dat a particular distance rearward of the needle bar guideline N. The needle bar guideline Nand the auxiliary guidelines Nand Neach extend from the left end to the right end of the image F. The thickness of each of the second guideline N, the needle bar guideline N, and the auxiliary guidelines Nto Nis, for example, 2 mm. The particular distance is a value set by the field K. In a case where the type of the guide pattern is the fourth guide pattern, the controllergenerates an image Fshown in. The image Fincludes the second guideline N, the needle bar guideline N, and a circle N. The circle Nis a circle with a diameter of a particular value and is centered at the needle position NP. The particular value is a value set by the field K.

The controllerdetermines whether the movement detectoris connected (S). In response to determining that the movement detectoris not connected (S: NO), the controllerperforms the processing of Sdescribed later. In response to determining that the movement detectoris connected (S: YES), the controlleracquires the color and fill mode of the first guideline (S). The first guideline is a guide pattern indicating the position of the detection region M in the short direction D. In this embodiment, the first guideline is selected by the user from among a region guideline and a separated guideline. The region guideline extends in the longitudinal direction Dat the location of the detection region M. The separated guideline extends in the longitudinal direction Dat a particular distance U from the position of the detection region M and at a location separated from the detection region M in the forward feed direction F. The color of the first guideline is set from among 16 different colors by using a sub-screen similar to the sub-screen Kshown in, which is displayed when the key image Jis selected on the screen Gshown in.

The fill mode is a mode in which the image includes a mask representing the shape of the housingand the presser footof the movement detector. According to this embodiment, the fill mode is one of two types of fill mode: a mode in which the image includes a background color mask filled with the background color, and a mode in which the image includes a particular color mask filled with a particular color that is different from the background color. The particular color is, for example, black.

The controlleradds the first guideline and the icon of the color acquired in Sto the image processed in Sbased on the color of the first guideline acquired in S(S). When adding the region guideline as the first guideline and an icon to the image F, the controllergenerates an image F. The image Fincludes a first guideline Nand an icon Nin addition to the second guideline N, the needle bar guideline N, and the auxiliary guidelines Nto N. The first guideline Nextends in the longitudinal direction Dat the position of the detection region M. In other words, the first guideline Nrepresents the position of the detection region M in the short direction D, and the detection region M is located on the first guideline N. The thickness of the first guideline Nis, for example, 5 mm, which is thicker than each of the second guideline N, the needle bar guideline N, and the auxiliary guideline N. The first guideline Nextends from the left end to the right end of the image F. The icon Nhas a rectangular shape (specifically, a square shape), for example. The length of the icon Nin the short direction Dand the longitudinal direction Dis, for example, 12 mm, which is longer than the thickness of the first guideline N. The icon Nis disposed between the first guideline Nand the auxiliary guideline Nin the short direction D. The icon Nis disposed leftward of the auxiliary guideline Nin the longitudinal direction D.

When adding the separated guideline as the first guideline and an icon to the image F, the controllergenerates an image F. The image Fincludes a first guideline Nand an icon Nin addition to the second guideline N, the needle bar guideline N, and the auxiliary guidelines Nto N. The first guideline Nextends in the longitudinal direction Dat the particular distance U from the position of the detection region M and at a location separated from the detection region M in the forward feed direction F. The thickness of the first guideline Nis, for example, 5 mm, which is thicker than the second guideline N, the needle bar guideline N, and the auxiliary guideline N. The icon Nhas a rectangular shape (specifically, a square shape), for example. The length of the icon Nin the short direction Dand the longitudinal direction Dis, for example, 12 mm, which is longer than the thickness of the first guideline N. The icon Nis disposed between the first guideline Nand the auxiliary guideline Nin the short direction D. The icon Nis disposed leftward of the auxiliary guideline Nin the longitudinal direction D.

Each of the first guidelines Nand Nand the icons Nand Nhas a white outline (border) to increase visibility on the sewing workpiece C. The thickness of the first guideline Nis thicker than the length of the detection region M in the short direction D. For example, the thickness of the first guideline is more than twice the length of the detection region M in the short direction D. By making the thickness of the first guidelines Nand Nthicker than the length of the detection region M in the short direction D, the controllerincreases the possibility that the detection region M is disposed on the first guideline Nor Neven when the projection position of the first guideline Nor Nis slightly deviated. More specifically, the accuracy of the position of the projected image is approximately ± (plus or minus) 1 mm when the projectorprojects the image onto the sewing workpiece C. Since the thickness of the first guideline Nis 2 mm or larger, it is guaranteed that the sewing workpiece C is within a range where the sensorof the movement detectordetects the sewing workpiece C, provided that the entirety of the projected guideline Nis on the sewing workpiece C. The projection mode of the icon Nor Nis set by the processing shown in, and may not be set by the processing shown inor may be temporarily set by the processing shown in.

The controllerdetermines whether to fill the image based on the fill mode acquired in S(S). In response to determining that the image is not to be filled (S: NO), the controllerperforms the processing of Sdescribed later. In response to determining that the image is to be filled (S: YES), the controlleracquires a mask of the movement detector(S). The controllerdetermines whether the color used for filling is the background color (S). In response to determining that the color of the mask to be added to the image Fis the background color (S: YES), the controllergenerates an image Fin which a background color mask Wis added to the image F(S). In response to determining that the color of the mask to be added to the image Fis the background color (S: YES), the controllergenerates an image Fin which the background color mask Wis added to the image F(S). In response to determining that the color of the mask to be added to the image Fis not the background color (S: NO), the controllergenerates an image Fin which a particular color mask Wis added to the image F(S). As in Sand S, the controlleradds the mask to the image containing the first guideline, the second guideline, and the auxiliary guidelines as the guide pattern, thereby generating the image containing the guide pattern projected in the range excluding the range in which the housingof the movement detectoris disposed. Subsequent to Sor S, the controllertransfers the generated image to the projector(S). The controllerends the image generation process.

The controllercontrols the projectorto start a projection process of projecting an image toward the bed surface(S). More specifically, the controllerstarts projecting the image acquired in Sand including an icon in steady red based on the projection mode of the icon in a case where the stitch regulating function is “ON” and the sewing mode is “not selected” in the tableof. The color of the icon in Sindicates that the operating state of the sewing machineis such that driving of the needle barbased on the movement of the sewing workpiece C cannot be performed. In this embodiment, since the projectorprojects the image toward the bed surfaceof the bedfrom diagonally above the sewing workpiece C placed on the bed surface, the image is processed to correct distortion of the image.

The controllerprojects the image in which the position of the guide pattern is changed based on the thickness of the sewing workpiece C acquired in S. The projectoris located leftward of the needle bar. The greater the thickness of the sewing workpiece C, the closer the upper surface of the sewing workpiece C is to the lens of the projector. If the projectorprojects the same image regardless of the thickness of the sewing workpiece C, the position of the upper surface of the sewing workpiece C in the image projected onto the sewing workpiece C is shifted leftward relative to the position of the upper surface of the sewing workpiece C in the image projected onto the sewing workpiece C when the sewing workpiece C has a small thickness. By correcting the position of the guide pattern in the image projected by the projectoraccording to the thickness of the sewing workpiece C, the position of the guide pattern in the image projected onto the upper surface of the sewing workpiece C is approximately constant regardless of the thickness of the sewing workpiece C. For example, in this embodiment, the controllercalculates the position of the guide pattern according to the thickness of the sewing workpiece C by using the thickness acquired in Sby the following procedure. The controllerconverts three-dimensional coordinates of the world coordinate system of a feature point into three-dimensional coordinates of a point in the projection coordinate system by using a translation vector for converting three-dimensional coordinates of the world coordinate system into three-dimensional coordinates of the projection coordinate system. The controllertransforms the three-dimensional coordinates of the projection coordinate system of the feature point into projection coordinates on a normalized image, taking into consideration distortion of the projection lens of the projector. A normalized projector is a projector where the distance from the optical center to the screen surface is a unit length. The controllertransforms the coordinates on the normalized image in the projection coordinate system into image coordinates by using internal variables of the projector. With the correction process described above, when projecting an image onto the sewing workpiece C having a large thickness, the controllerprojects a larger image rightward than when projecting the same image on the sewing workpiece C having a smaller thickness. Accordingly, the position and size of the image projected onto the upper surface of the sewing workpiece C are roughly the same, regardless of the thickness of the sewing workpiece C. As shown in, when the image Fshown inis acquired in S, the controllerprojects the image Fincluding the icon Nin steady red toward the bed surface.

The controllerdetermines whether the sewing mode has been selected on the screen G(S). In response to determining that the sewing mode has not been selected (S: NO), the controllerreturns the processing to S. In response to determining that any of the key images Jto Jhas been selected (S: YES), the controllerdetermines whether selection of the continuous mode has been detected. In response to determining that selection of the continuous mode has been detected (S: YES), the controllerprojects an image in which the icon in the image acquired in Sis steady green, which is different from the color in S, based on the projection mode of the icon in a case where the stitch regulating function is “ON” and the sewing mode is the “continuous mode” in the tableof(S). The color of the icon in Sindicates that the operating state of the sewing machineis such that driving of the needle barbased on the movement of the sewing workpiece C is performable. As shown in, when the image Fshown inis acquired in S, the controllerprojects the image Fincluding the icon Nin steady green toward the bed surface. The icon Nshown inand the icon Nshown indiffer from each other in color, that is, the icons have the same shape and position.