JP7794032B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Conventionally, image forming devices that form images on fabric media include a stage on which the media is placed and an ejection head that ejects ink onto the media placed on the stage.

Since the thickness of fabric media varies greatly depending on the type, the vertical distance between the media placed on the stage and the ejection head also fluctuates, resulting in a decrease in image formation quality. Therefore, to maintain a constant distance between the media and the ejection head, there is technology that raises and lowers the stage each time an image is formed on new media (see, for example, Patent Document 1).

However, raising and lowering the stage each time an image is formed on new media poses the problem of reduced throughput. On the other hand, reducing the amount of stage lowering in order to improve throughput creates a new problem: it becomes impossible to maintain image formation quality for a wide variety of media with different thicknesses.

The present invention was made to solve these problems, and aims to provide technology that maintains image formation quality while improving throughput in an image forming device that forms images on fabric media.

In order to solve the above problem, one aspect of the present invention comprises a stage that supports fabric media, an ejection head that is positioned above the stage and ejects ink toward the media supported by the stage to form an image on the media, an elevator mechanism that raises and lowers the stage, a height detection sensor that detects when the media supported by the stage has reached an image formation position, and a controller that controls the elevator mechanism based on the detection results of the height detection sensor, wherein the controller is configured to be switchable between a first control mode in which, prior to causing the ejection head to form an image on the media supported by the stage, the stage is lowered to a first position and then raised until the height detection sensor detects the media, and a second control mode in which the stage is lowered to a second position above the first position and then raised until the height detection sensor detects the media.

According to the present invention, an image forming apparatus that forms images on fabric media can maintain image formation quality while improving throughput.

FIG. FIG. FIG. 2 is a hardware configuration diagram of a control block that controls the operation of the image forming apparatus. Functional block diagram of the controller. 10 is an example of an image formation instruction screen. FIG. 2 is a diagram showing the vertical position of the stage. 4 is a flowchart of an image forming process according to the present embodiment. 10 is a flowchart of an image forming process according to a modified example.

The image forming apparatus 1 according to this embodiment will now be described with reference to the drawings. FIG. 1 is a perspective view of the image forming apparatus 1. FIG. 2 is a front view of the image forming apparatus 1. The image forming apparatus 1 according to this embodiment is an apparatus that forms an image on a fabric medium M (see FIG. 6). The medium M may be, for example, a T-shirt or fabric before sewing.

As shown in Figures 1 and 2, the image forming apparatus 1 includes a stage 10. The stage 10 is a plate-shaped member that supports the media M on its upper surface. The stage 10 is supported by the housing 2 of the image forming apparatus 1 so that it can move up and down and slide in the sub-scanning direction (front-to-back direction) perpendicular to the up-and-down direction and the main scanning direction (left-to-right direction).

More specifically, the stage 10 is supported by an elevator mechanism 11 so that it can be raised and lowered. The elevator mechanism 11 raises and lowers the stage 10 by transmitting the driving force of an elevator motor 12 (see Figure 3). The stage 10 and elevator mechanism 11 are supported by a slider 14 that slides on a slide rail 13 extending in the sub-scanning direction. The slider 14 slides in the sub-scanning direction along the slide rail 13 by transmitting the driving force of a slide motor 15 (see Figure 3) via a timing belt 16.

The image forming device 1 includes a carriage 20. The carriage 20 is positioned above the stage 10. The carriage 20 supports, on its underside, an ejection head 21 that ejects ink. The ejection head 21 has multiple nozzles that eject ink of each color (e.g., cyan, magenta, yellow, and black). The carriage 20 is supported by the housing 2 so that it can move back and forth in the up-down direction and in the main scanning direction (left-right direction), which is perpendicular to the sub-scanning direction (front-back direction).

More specifically, the carriage 20 is supported on guide rails 22, 23 that extend in the main scanning direction. The driving force of a carriage motor 24 (see Figure 3) is transmitted to the carriage 20 via a timing belt 25, causing the carriage 20 to move back and forth in the main scanning direction along the guide rails 22, 23. As the carriage 20 moves back and forth in the main scanning direction, ink is ejected from the ejection head 21 at a predetermined timing, forming an image on the medium M supported on the stage 10 located below the ejection head 21.

The image forming apparatus 1 is equipped with a maintenance unit 26. The maintenance unit 26 is disposed on one side of the stage 10 in the main scanning direction, in a position facing the carriage 20. The maintenance unit 26 includes, for example, a suction cap that caps the nozzle surface of the ejection head 21, a suction pump that sucks ink from the ejection head 21 capped by the suction cap, and a wiping member that wipes the nozzle surface of the ejection head 21.

The image forming apparatus 1 is equipped with an ink receiving section 27. The ink receiving section 27 is disposed on the other side of the stage 10 in the main scanning direction, in a position facing the ejection head 21. The ejection head 21 ejects ink toward the ink receiving section 27, thereby preventing ink from clogging the nozzles.

The image forming apparatus 1 is equipped with a height detection sensor 30 (see Figure 3). The height detection sensor 30 detects when the media M supported on the stage 10 has reached the image forming position, and outputs a detection signal indicating the detection result to the controller 100. The image forming position is a position where a predetermined vertical gap (a gap that can maintain image formation quality) is formed between the ejection head 21 and the media M. The thickness of the media M varies depending on the type, and the media M may be placed on the stage 10 in a bent state. Therefore, the vertical position of the stage 10 when the media M has reached the image forming position may differ each time an image is formed.

The height detection sensor 30 includes, for example, a light-emitting unit 31 and a light-receiving unit 32. The light-emitting unit 31 and the light-receiving unit 32 are positioned at positions separated in the main scanning direction across the stage 10. The light-emitting unit 31 outputs light toward the light-receiving unit 32. When the media M supported on the stage 10 is positioned below the image formation position, the light-receiving unit 32 receives the light output from the light-emitting unit 31. On the other hand, when the media M supported on the stage 10 reaches the image formation position, the light paths of the light-emitting unit 31 and the light-receiving unit 32 are blocked. As a result, the light-receiving unit 32 cannot receive the light output from the light-emitting unit 31. The height detection sensor 30 then outputs a detection signal to the controller 100 in response to the light-receiving unit 32 not receiving light.

The image forming apparatus 1 also includes a lift sensor (e.g., a rotary encoder of the lift motor 12) that detects the vertical position of the stage 10, a slide sensor (e.g., a rotary encoder of the slide motor 15) that detects the position of the stage 10 in the sub-scanning direction, and a carriage sensor (e.g., a sensor that reads an encoder sheet attached on the movement path of the carriage 20) that detects the position of the carriage 20 in the main scanning direction.

Figure 3 is a hardware configuration diagram of the control block that controls the operation of image forming device 1. As shown in Figure 3, image forming device 1 has a configuration in which a CPU (Central Processing Unit) 101, RAM (Random Access Memory) 102, ROM (Read Only Memory) 103, HDD (Hard Disk Drive) 104, and I/F 105 are connected via a common bus 109.

The CPU 101 is a computing unit that controls the overall operation of the image forming apparatus 1. The RAM 102 is a volatile storage medium that allows for high-speed reading and writing of information, and is used as a working area when the CPU 101 processes information. The ROM 103 is a read-only non-volatile storage medium that stores programs such as firmware. The HDD 104 is a non-volatile storage medium with a large storage capacity that allows for reading and writing of information, and stores the OS (Operating System), various control programs, application programs, etc.

Image forming device 1 processes control programs stored in ROM 103, information processing programs (application programs) loaded into RAM 102 from storage media such as HDD 104, and other programs using the calculation functions of CPU 101. This processing configures a software control unit that includes various functional modules of image forming device 1. The combination of this configured software control unit and the hardware resources installed in image forming device 1 configures functional blocks that realize the functions of image forming device 1. In other words, CPU 101, RAM 102, ROM 103, and HDD 104 configure controller 100, which controls the operation of image forming device 1.

The I/F 105 is an interface that connects the lift motor 12, slide motor 15, ejection head 21, carriage motor 24, height detection sensor 30, and operation panel 40 to the common bus 109. The controller 100 controls the lift motor 12, slide motor 15, ejection head 21, carriage motor 24, height detection sensor 30, and operation panel 40 via the I/F 105.

The operation panel 40 includes an operation unit that accepts input operations from the user and a display that notifies the user of information. The operation unit includes, for example, hard keys and a touch panel superimposed on the display. The operation panel 40 obtains information from the user through the operation unit and provides the information to the user through the display.

Figure 4 is a functional block diagram of the controller 100. As shown in Figure 4, the controller 100 mainly comprises a mode determination unit 111, an elevation processing unit 112, a slide processing unit 113, and an image formation processing unit 114. The image formation processing shown in Figure 7 is realized by the functional blocks 111 to 114 performing processing in conjunction with each other.

The mode determination unit 111 determines the lifting/lowering control mode (first control mode, second control mode) of the stage 10 that is performed prior to forming an image on the media M supported by the stage 10. If the type of media M differs between the previous image formation process and the current image formation process, the mode determination unit 111 operates the lifting/lowering processing unit 112 in the first control mode. On the other hand, if the type of media M is the same between the previous image formation process and the current image formation process, the mode determination unit 111 operates the lifting/lowering processing unit 112 in the second control mode.

Figure 5 is an example of an image formation instruction screen. The mode determination unit 111 displays the image formation instruction screen on the display of the operation panel 40. The image formation instruction screen includes a [Thick] button, a [Thin] button, and a [Start image formation] button. The [Thick] button corresponds to thick media M being placed on the stage 10. The [Thin] button corresponds to thin media M being placed on the stage 10. In other words, the [Thick] button and the [Thin] button correspond to the type of media M placed on the stage 10. The [Start image formation] button corresponds to starting the image formation process shown in Figure 7.

The user then selects either the [Thick] button or the [Thin] button, and presses the [Start Image Formation] button. The mode determination unit 111 determines that the types of media M are different if the [Thick] button or the [Thin] button selected at the start of the previous image formation process is different from the button selected at the start of the current image formation process. On the other hand, the mode determination unit 111 determines that the types of media M are the same if the [Thick] button or the [Thin] button selected at the start of the previous image formation process is the same as the button selected at the start of the current image formation process.

That is, the mode determination unit 111 accepts an input operation via the operation panel 40 indicating whether the type of media M is the same as the previous one or the current one. However, the method for determining whether the type of media M is the same as the previous one or the current one is not limited to the example described above.

Prior to causing the ejection head 21 to form an image on the medium M supported on the stage 10, the lifting/lowering processing unit 112 lowers the stage 10 and then raises the stage 10 until the medium M reaches the image formation position. The lifting/lowering processing unit 112 raises and lowers the stage 10 in accordance with the lifting/lowering control mode set by the mode determination unit 111. More specifically, the lifting/lowering processing unit 112 changes the position to which the stage 10 is lowered in accordance with the lifting/lowering control mode set by the mode determination unit 111.

Figure 6 is a diagram showing the vertical position of the stage 10. More specifically, Figure 6(A) shows the first position of the stage 10. Figure 6(B) shows the second position of the stage 10. Figure 6(C) shows the position of the stage 10 when the media M reaches the image forming position. The first position (Figure 6(A)) and the second position (Figure 6(B)) are positions below the position of the stage 10 when the media M reaches the image forming position (Figure 6(C)). The first position is, for example, the lower end of the lifting range of the stage 10. The second position is a position above the first position.

In the first control mode, the lifting/lowering processing unit 112 lowers the stage 10 to the first position shown in FIG. 6(A), and then raises the stage 10 to the position shown in FIG. 6(C). On the other hand, in the second control mode, the lifting/lowering processing unit 112 lowers the stage 10 to the second position shown in FIG. 6(B), and then raises the stage 10 to the position shown in FIG. 6(C). In other words, the second control mode is a lifting/lowering control mode in which the amount of lifting/lowering of the stage 10 is smaller than in the first control mode.

The slide processing unit 113 drives the slide motor 15 to slide the stage 10 in the sub-scanning direction. In response to the start of image formation processing, the slide processing unit 113 slides the stage 10 backward to a position where it can face the ejection head 21. Furthermore, during the image formation process by the ejection head 21, the slide processing unit 113 slides the stage 10 backward so that the area of the medium M on which the next image is to be formed faces the ejection head 21. Furthermore, in response to the completion of image formation on the medium M, the slide processing unit 113 slides the stage 10 forward to a position where the medium M can be removed from the stage 10.

The image formation processing unit 114 forms an image on the medium M supported by the stage 10 by operating the carriage 20 and the ejection head 21 in conjunction with each other. More specifically, the image formation processing unit 114 drives the carriage motor 24 to move the carriage 20 in the main scanning direction. Furthermore, the image formation processing unit 114 causes the ejection head 21 to eject ink while the carriage 20 moves in the main scanning direction.

Figure 7 is a flowchart of the image formation process according to this embodiment. The user places the media M on the stage 10, which has been pulled forward from the carriage 20. Next, the user selects either the "Thick" button or the "Thin" button on the image formation instruction screen shown in Figure 5, and presses the "Start Image Formation" button. Then, in response to the pressing of the "Start Image Formation" button, the controller 100 starts the image formation process. Note that the vertical position of the stage 10 at the start of the current image formation process is the position it was in when the image was formed in the previous image formation process.

First, the slide processing unit 113 drives the slide motor 15 to slide the stage 10 supporting the media M backward to a position where it can face the ejection head 21 (S701).

Next, the mode determination unit 111 determines whether the type of media M on which an image is to be formed in the current image formation process is the same as the type of media M on which an image was formed in the previous image formation process, based on the button selected on the image formation instruction screen (S702). Note that it is assumed that which button was selected at the start of the previous image formation process is stored in the HDD 104. The mode determination unit 111 then determines the lift control mode based on whether the type of media M is the same as the previous one.

Next, the lifting/lowering processing unit 112 raises and lowers the stage 10 in accordance with the lifting/lowering control mode determined by the mode determination unit 111 (S703 to S706).

If the mode determination unit 111 determines the first control mode (S702: Yes), the lift processing unit 112 drives the lift motor 12 to lower the stage 10 supporting the media M to the first position shown in FIG. 6A (S703). Next, the lift processing unit 112 drives the lift motor 12 in the reverse direction to raise the stage 10 until the media M is detected by the height detection sensor 30, in other words, until the media M supported on the stage 10 reaches the image formation position (S706: No) (S705). Then, when the media M supported on the stage 10 reaches the image formation position (S706: Yes), the lift processing unit 112 stops the lift motor 12.

On the other hand, if the mode determination unit 111 determines the second control mode (S702: No), the lifting/lowering processing unit 112 drives the lifting motor 12 to lower the stage 10 supporting the media M to the second position shown in FIG. 6B (S704). Next, the lifting/lowering processing unit 112 raises the stage 10 (S705) until the media M supported by the stage 10 reaches the image formation position (S706: No). The processing of steps S705-S706 is the same as in the first control mode.

Next, the slide processing unit 113 and image formation processing unit 114 form an image on the medium M supported by the stage 10 (S707). More specifically, the image formation processing unit 114 drives the carriage motor 24 to move the carriage 20 in the main scanning direction and causes the ejection head 21 to eject ink at a predetermined timing. The slide processing unit 113 also drives the slide motor 15 to slide the stage 10 backward a predetermined distance so that the area of the medium M on which the next image will be formed faces the ejection head 21. By repeating this process, an image is formed on the medium M.

Next, the slide processing unit 113 drives the slide motor 15 to slide the stage 10 forward to a position in front of the ejection head 21 (a position where the media M can be removed) (S708). Note that in this embodiment, the stage 10 is not lowered after the image is formed on the media M. That is, in this embodiment, the stage 10 is slid forward without being lowered in step S708.

The above embodiment provides the following advantages, for example:

If the type of media M is different between the previous and current printing (S702: Yes), the thickness of the media M may have changed significantly, and therefore the position of the stage 10 when the media M reaches the image forming position may also change significantly. In such a case, the stage 10 is lowered significantly (S703), and then raised until the media M reaches the image forming position (S705-S706). This makes it possible to maintain image formation quality for a wide variety of media M with different thicknesses.

On the other hand, if the type of media M is the same this time as it was last time (S702: No), the thickness of the media M does not change significantly, and the amount of flexure of the media M only changes slightly, so the position of the stage 10 when the media M reaches the image forming position does not change significantly. In such a case, the amount of descent of the stage 10 is reduced compared to step S703 (S704). This improves the throughput of the image forming process.

Furthermore, according to the above embodiment, the user is prompted via the operation panel 40 to input whether the type of media M is the same as the previous one and the current one, making it possible to maintain image formation quality and improve throughput with a simple configuration. However, the method for determining whether the type of media M is the same as the previous one and the current one is not limited to the above example. As another example, the controller 100 may take a picture of the media M supported on the stage 10 with a camera and make a determination based on the captured image.

In addition, in the above embodiment, an example was described in which the second position was a fixed position, but the second position may also be variable. The controller 100 may be configured to be able to change the second position in accordance with a user instruction via the operation panel 40, for example. Then, if priority is given to maintaining image formation quality, the second position can be changed downward, and if priority is given to improving throughput, the second position can be changed upward.

[Modification]
8 is a flowchart of an image forming process according to a modified example. A detailed description of the commonalities with the above embodiment will be omitted, and the following description will focus on the differences. The image forming process shown in FIG. 8 differs from the image forming process shown in FIG. 7 in that step S704 is omitted and step S801 is added.

In response to the formation of an image on the medium M supported by the stage 10 (S707), the lifting/lowering processing unit 112 according to the modified example drives the lifting motor 12 to lower the stage 10 to the second position (S801). Then, the slide processing unit 113 according to the modified example drives the slide motor 15 to slide the stage 10, which has been lowered to the second position, forward (S708). In other words, when the next image formation process is started, the stage 10 will be located at the second position.

Furthermore, since the stage 10 has already been lowered to the second position in the previous image formation process, the lifting/lowering processing unit 112 according to the modified example does not need to lower the stage 10 when the current image formation process is in the second control mode (i.e., step S704 is omitted). Furthermore, the lifting/lowering processing unit 112 according to the modified example only needs to lower the stage 10 from the second position to the first position when the current image formation process is in the first control mode (S703). That is, in step S703 of FIG. 8, the amount of descent of the stage 10 is less than in step S703 of FIG. 7.

In this modified example, the stage 10 is lowered to the second position at the end of the previous image formation process, thereby reducing the amount of lowering of the stage 10 in the current image formation process. This improves the throughput of the image formation process while maintaining the quality of the image formation. The processing timing of step S801 is not limited to the example in Figure 8, as long as it occurs after the ejection head 21 has formed an image on the previous medium M and before the current medium M is supported by the stage 10.

The control method described above may be realized, for example, by a program. In other words, the control method is a method executed by a computer by causing an arithmetic unit, a storage unit, an input unit, an output unit, and a control unit to operate in cooperation with each other based on the program. The program may also be written to a storage unit or storage medium and distributed, or distributed via telecommunications lines, etc.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist of the invention. All technical matters included in the technical concept set forth in the claims are within the scope of the present invention. The above-described embodiments are preferred examples, but those skilled in the art will be able to realize various modifications based on the disclosed content. Such modifications are also included within the technical scope set forth in the claims.

DESCRIPTION OF SYMBOLS 1: Image forming apparatus 2: Housing 10: Stage 11: Elevating mechanism 12: Elevating motor 13: Slide rail 14: Slider 15: Slide motor 16, 25: Timing belt 20: Carriage 21: Ejection heads 22, 23: Guide rail 24: Carriage motor 26: Maintenance unit 27: Ink receiving section 30: Height detection sensor 31: Light emitting section 32: Light receiving section 40: Operation panel 100: Controller 101: CPU
102: RAM
103: ROM
104: HDD
105: I/F
109: Common bus 111: Mode determination unit 112: Elevation processing unit 113: Slide processing unit 114: Image formation processing unit

JP 2010-094840 A

Claims (7)

a stage to support fabric media;
an ejection head disposed above the stage and configured to eject ink toward the medium supported by the stage, thereby forming an image on the medium;
an elevation mechanism for raising and lowering the stage;
a height detection sensor that detects that the medium supported by the stage has reached an image forming position;
a controller that controls the lifting mechanism based on a detection result of the height detection sensor,
The controller, prior to causing the ejection head to form an image on the medium supported by the stage,
a first control mode in which the stage is lowered to a first position and then raised until the height detection sensor detects the medium;
a first control mode in which the stage is lowered to a second position above the first position, and a second control mode in which the stage is raised until the media is detected by the height detection sensor. When forming images on a plurality of the media in order, the controller
If the type of the media is different from the previous type, the device operates in the first control mode;
2. The image forming apparatus according to claim 1, wherein the image forming apparatus operates in the second control mode when the type of the media is the same as that of the previous image forming apparatus. an operation unit that accepts an input operation by a user;
3. The image forming apparatus according to claim 2, wherein the controller accepts, via the operation unit, an input operation indicating whether the type of the media is the same as that of the previous time. An image forming apparatus as described in claim 2 or 3, characterized in that the controller lowers the stage to the second position after causing the ejection head to form an image on the previous media and before the current media is supported by the stage. The image forming apparatus described in any one of claims 1 to 4, characterized in that the height detection sensor detects that the media supported by the stage has reached the image forming position where a predetermined vertical gap is formed between the media and the ejection head. The image forming apparatus of any one of claims 1 to 5, characterized in that the controller is configured to be able to change the second position. 7. The image forming apparatus according to claim 1, wherein the controller, in the first control mode, lowers the stage to the first position at the lower end of a lifting range of the stage.