JP5824943B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method.

  As an image forming apparatus, an ink jet type image forming apparatus is known. 2. Description of the Related Art As an inkjet image forming apparatus, an apparatus is known that forms an image by ejecting ink droplets from a recording head in which a plurality of nozzles arranged and a recording medium are relatively scanned and moved.

  Specifically, the ink droplets ejected from the nozzles form dots by adhering to the recording medium. As a result, an image is formed on the recording medium.

  Here, the ink droplets ejected from the nozzles of the recording head that is scanned and moved are divided into main droplets and sub-drops having a smaller ink amount than the main droplets, and adhere to the recording medium. This is because the ink droplets ejected from the nozzles of the recording head that is scanned and moved are ejected toward the recording medium in a shape having a tail from the upstream side to the downstream side in the scanning direction of the recording head. Ink droplets ejected from the nozzle start to form main droplets that become dots due to the aggregation of the ink due to surface tension at the tip portion toward the recording medium, and ink that has not coalesced into the main droplets becomes sub-droplets, It flies toward the recording medium in a state of being separated into a main droplet and a sub droplet. For this reason, the main dot by the main droplet is recorded on the recording medium, and the sub dot by the sub droplet adheres to the downstream side of the main dot in the scanning direction.

  When a plurality of dots are continuously recorded in the scanning direction of the recording head, the sub dot (sub droplet) corresponding to the main dot (main droplet) on the upstream side in the scanning direction is the main dot (main droplet). Are covered with another main dot (main droplet) formed adjacent to the downstream side in the scanning direction. However, among a plurality of main dots that are continuous in the scanning direction, sub-dots (sub-drops) corresponding to the most downstream main dot (main droplet) in the scanning direction, and discontinuous main dots (main drops) in the scanning direction The sub-dots (sub-drops) corresponding to are not covered by other main dots (main droplets), which may cause image quality degradation.

  As a technique for suppressing deterioration in image quality, Patent Document 1 extracts, as a boundary part, a pixel in which a satellite (sub-droplet) corresponding to a formed main droplet is not covered by another main droplet. In Patent Document 1, when a dot corresponding to the pixel at the boundary is formed, the recording head is scanned in a direction opposite to the scanning direction at the time of forming the main droplet formed earlier than the dot. As a result, in Patent Document 1, satellites (sub-droplets) are recorded by being superimposed on the other main droplets previously formed.

  However, in the technique disclosed in Patent Document 1, when recording a dot on the most downstream side in the scanning direction among a plurality of dots that are continuous in the scanning direction, It is necessary to scan the recording head in the reverse direction. For this reason, it is necessary to reciprocate the recording head for each dot group continuous in the scanning direction of the recording head. Further, in the technique disclosed in Patent Document 1, sub-dots recorded by sub-drops separated from the main droplets ejected at the most downstream in the scanning direction in a plurality of dots continuous in the scanning direction are changed to other main droplets. Therefore, the image quality may be deteriorated.

  The present invention has been made in view of the above, and an image forming apparatus capable of suppressing image quality deterioration caused by sub-droplets separated from main droplets for dot formation, which are generated by droplet discharge, And an image forming method.

  In order to solve the above-described problems and achieve the object, the image forming apparatus of the present invention includes a recording head that records dots corresponding to each pixel by ejecting ink droplets from each of the nozzles, and the recording head. Driving means for moving the image in the scanning direction at a first speed relative to the recording medium, a pixel group that is continuous in the scanning direction among the pixels that record the dots in the image data, and in the scanning direction Corresponding to the boundary pixel, an extraction means for extracting each of the discontinuous pixels as an image area, a specifying means for specifying a pixel located at the most downstream in the scanning direction in each of the image areas as a boundary pixel, The scanning speed of the recording head during dot recording is determined to be a second speed that is lower than the first speed, and the scanning speed of each position of the recording head in the scanning direction is determined. And control means for controlling said drive means in response to the scanning speed determining means for determining, determining which is the image forming apparatus having a.

  The image forming method of the present invention includes a recording head that records dots corresponding to each pixel by ejecting ink droplets from each of the nozzles, and the recording head at a first speed relative to the recording medium. An image forming method that is executed by an image forming apparatus that scans and moves in a scanning direction, wherein among pixels that record the dots in image data, a group of pixels that are continuous in the scanning direction, and Corresponding to the boundary pixel, a step of extracting each of the discontinuous pixels in the scanning direction as an image region, a step of identifying a pixel located at the most downstream in the scanning direction in each of the image regions as a boundary pixel, The scanning speed of the recording head at the time of dot recording is determined to be a second speed lower than the first speed, and at each position in the scanning direction of the recording head. Determining that the scanning speed, and controlling the drive means in response to the determined the scanning speed, an image forming method having a.

  According to the present invention, it is possible to provide an image forming apparatus and an image forming method capable of suppressing image quality deterioration caused by sub-drops generated by droplet discharge.

FIG. 1 is a perspective view illustrating a configuration example of a recording apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a hardware configuration of the recording apparatus according to the first embodiment. FIG. 3 is a schematic diagram showing an example of a state in which the main dots recorded by the main droplets and the sub dots recorded by the sub droplets are attached to the recording medium. FIG. 3A is a diagram in which the recording head scans in the scanning forward direction. FIG. 4B is a schematic diagram illustrating a recording state of main dots and sub-dots when ink droplets are ejected while being moved, and (B) is a main dot when ink droplets are ejected while the recording head is scanned and moved in the reverse scanning direction. FIG. 6 is a schematic diagram illustrating a recording state of sub-dots. FIG. 4 is a schematic diagram illustrating an example of a print area and an image area. FIG. 5 is a schematic diagram showing the boundary part, (A) is a schematic diagram showing the boundary part when the recording head ejects ink droplets while being scanned and moved in the scanning forward direction, and (B) is FIG. 5 is a schematic diagram illustrating a boundary portion when an ink droplet is ejected while the recording head is scanned and moved in the scanning reverse direction. FIG. 6 is a schematic diagram showing an example of the state of adhesion of the main droplet and the sub-droplet to the recording medium. FIG. 6A shows a case where the sub-dots recorded by the sub-drops separated from the different main droplets It is a schematic diagram which shows the state which is not covered with a main dot, (B) is the state in which the sub dot recorded by the sub drop isolate | separated from the different main drop in the prior art was covered with the main dot of this different main drop. It is a schematic diagram shown. FIG. 7 is a schematic diagram showing the relationship between main dots and sub-dots when dots are recorded discontinuously in the scanning direction in the prior art. FIG. 8 is a schematic diagram showing the relationship between the position coordinates in the scanning movable range AB in the scanning direction of the recording head and the scanning speed of the recording head in the conventional recording apparatus. FIG. 9 is a schematic diagram illustrating main dots and sub-dots recorded by the recording apparatus according to the first embodiment. FIG. 10 is a functional block diagram in which the recording apparatus according to the first embodiment is divided for each function realizing unit determined based on hardware and software. FIG. 11 is a schematic diagram showing the relationship between the position coordinates in the scan movable range AB in the scan direction of the print head and the scan speed of the print head in the scan forward direction in the printing apparatus of the first embodiment. FIG. FIG. 12 is a schematic diagram showing the relationship between the position coordinates in the scan movable range AB in the scan direction of the print head and the scan speed of the print head in the reverse scan direction in the printing apparatus of the first embodiment. FIG. FIG. 13 is a flowchart showing an overall flow of the image forming process in the first embodiment. FIG. 14A is a schematic diagram illustrating the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the first embodiment. FIG. 14B is a schematic diagram illustrating the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the first embodiment. FIG. 15 is a functional block diagram in which the recording apparatus according to the second embodiment is divided for each function realizing unit determined based on hardware and software. FIG. 16 is a schematic diagram illustrating the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the second embodiment. FIG. 17 is a schematic diagram illustrating the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the second embodiment. FIG. 18 is a functional block diagram in which the recording apparatus according to the third embodiment is divided for each function realizing means determined based on hardware and software. FIG. 19 is a schematic diagram showing the relationship between main dots and sub-dots recorded by the recording apparatus of the third embodiment. FIG. 19A shows the relationship between main dots and sub-dots during black dot recording. It is a schematic diagram, and (B) is a schematic diagram showing the relationship between main dots and sub-dots during yellow dot recording. FIG. 20 is a schematic diagram illustrating a relationship between main dots and sub dots recorded by the recording apparatus according to the third embodiment. FIG. 21 is a functional block diagram in which the recording apparatus according to the fourth embodiment is divided for each function realizing means determined based on hardware and software. FIG. 22 is a schematic diagram showing a recording state of dots when dots are continuously recorded in the scanning direction by the recording apparatus according to the fourth embodiment, and (A) is a predetermined number of consecutive dots or less. FIG. 6B is a schematic diagram illustrating a dot recording state when continuously recording in the scanning direction, and FIG. 7B illustrates a dot recording state when dots exceeding a predetermined number of consecutive recordings are continuously recorded in the scanning direction. It is a schematic diagram shown. FIG. 23 is a functional block diagram in which the recording apparatus according to the fifth embodiment is divided for each function realizing means determined based on hardware and software. FIG. 24 is a schematic diagram showing the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the fifth embodiment. FIG. 25 is a schematic diagram illustrating the relationship between the position coordinates of the recording head in the scanning direction and the scanning speed of the recording head in the scanning forward direction in the recording apparatus according to the fifth embodiment.

  Hereinafter, an embodiment of an image forming apparatus and an image forming method according to the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a perspective view showing an example of an ink jet recording apparatus 10 as an image forming apparatus according to the present embodiment.

  As shown in FIG. 1, an ink jet recording apparatus (hereinafter referred to as a recording apparatus) 10 includes a carriage 24 that scans and moves in a scanning direction (arrow X direction in FIG. 1). The carriage 24 is coupled to a part of the driving belt 7 of the transmission mechanism 14 that transmits the driving force of the carriage driving unit 60. The carriage 24 is slidably supported along a guide shaft 32 extending in the scanning direction (arrow X direction). For this reason, the carriage 24 scans and moves in the scanning direction (arrow X direction) along the guide shaft 32 by driving the carriage driving unit 60.

  The carriage 24 has a recording head 26 mounted thereon. Therefore, the recording head 26 scans and moves in the scanning direction (arrow X direction) as the carriage 24 scans. The recording head 26 discharges ink from the nozzles according to the ink jet method, and records dots corresponding to the respective pixels on the recording medium P. As the recording head 26, a known recording head using an electromechanical transducer such as a piezoelectric method or a heating method may be used.

  The carriage 24 is mounted with an ink cartridge 28 that stores ink to be supplied to the recording head 26 together with the recording head 26. The ink cartridge 28 is detachably attached to the carriage 24.

  The case where the recording apparatus 10 of the present embodiment is a color recording apparatus that discharges ink droplets of a plurality of colors will be described. For this reason, in the present embodiment, for example, four ink cartridges 28 each containing magenta (M), cyan (C), yellow (Y), and black (K) ink are mounted as the ink cartridges 28. Explain the case. The recording apparatus 10 may be an apparatus that ejects one color ink, and is not limited to a configuration that forms a multicolor image.

  The recording apparatus 10 is provided with a paper feeding mechanism 12 on which the recording medium P is placed. The recording medium P placed on the paper feed mechanism 12 is transported by the transport driving unit 62 in a direction intersecting the scanning direction (arrow Y direction in FIG. 1). The recording apparatus 10 includes a conveyance roller 42, a pinch roller 40, a pinch roller holder 34 that supports the pinch roller 40, a conveyance roller gear 38, and the like. Then, the conveyance roller 42 is driven by the driving of the conveyance driving unit 62, and the recording medium P pressed against the conveyance roller 42 by the pinch roller holder 34 is conveyed in the arrow Y direction.

  In addition, the recording apparatus 10 is provided with a detection unit 48 that detects the position of the recording medium P in the transport direction (arrow Y direction). By detecting the position of the recording medium P by the detection unit 48, the position of the recording medium P in the transport direction (arrow Y direction) is adjusted. Further, the recording apparatus 10 is provided with a scale 30 for indicating an absolute position in the scanning direction (arrow X direction) of the carriage 24. One of the scales 30 is fixed to the chassis 16 and the other is supported by a leaf spring (not shown).

  The recording medium P is conveyed by driving the conveyance driving unit 62, and the leading end of the recording medium P in the conveyance direction (arrow Y direction) is conveyed by the recording head 26 to an area where ink droplets are ejected. Then, the recording head 26 that is scanned in the scanning direction (the arrow X direction in FIG. 1) by driving the carriage driving unit 60 ejects ink droplets onto the recording medium P. As a result, on the recording medium P, the recording head 26 is scanned in the scanning direction (arrow X direction) of the recording head 26 to form dots corresponding to the pixels. Then, the recording medium P is transported in the transport direction (arrow Y direction) and the ink droplets are ejected by scanning the recording head 26 in the scanning direction. In the transport direction (arrow Y direction), dots corresponding to the pixels are formed to form an image.

  Further, the recording apparatus 10 includes a discharge roller 44. The discharge roller 44 is driven by the conveyance driving unit 62 and discharges the recording medium P on which an image is formed by the recording head 26 and supported by the spur holder 46 to the outside of the recording apparatus 10.

  The recording apparatus 10 further includes a recovery device 22 for removing clogged nozzles and the like with respect to the recording head 26. The recovery device 22 includes a capping mechanism 20 for capping the nozzles of the recording head 26 and a wiping mechanism 18 for cleaning the discharge port surface of the nozzles of the recording head 26. The recovery device 22 forcibly discharges ink from the discharge port surface of the nozzle by the capping mechanism 20 and performs discharge recovery processing.

  Further, the recording apparatus 10 includes a control unit 50 for controlling each unit of the recording apparatus 10. The control unit 50 is electrically connected to various drive units such as the transport drive unit 62 and the carriage drive unit 60 described above, and controls each unit of the apparatus.

  Next, the hardware configuration of the recording apparatus 10 will be described. FIG. 2 is a block diagram illustrating a hardware configuration of the recording apparatus 10.

  As illustrated in FIG. 2, the recording apparatus 10 includes a control unit 50, an operation unit 49, a detection unit 48, an interface 61, a carriage motor driver 58, and a conveyance motor driver 64. The operation unit 49, the detection unit 48, the interface 61, the carriage motor driver 58, and the transport motor driver 64 are electrically connected to the control unit 50.

  Although not shown in FIG. 1, the operation unit 49 inputs or outputs various types of information. Examples of the operation unit 49 include a keyboard and a display with a touch panel. When the user instructs the operation unit 49 to operate, various types of information are input from the operation unit 49 to the control unit 50.

  The carriage motor driver 58 is a motor driver that drives the carriage driving unit 60 under the control of the control unit 50. The transport motor driver 64 is a motor driver that drives the transport drive unit 62 under the control of the control unit 50. The interface 61 receives image data to be recorded by the recording device 10 from an external device such as a personal computer.

  The control unit 50 includes a CPU (CentrAl Processing Unit) 50A, a ROM (ReAd Only Memory) 50E, a RAM (Random Access Memory) 50D, an ASIC 50B (Special Purpose Integrated Circuit), and a system bus 50C connecting them. ing. The control unit 50 is electrically connected to each unit provided in the recording apparatus 10.

  The ROM 50E stores a program for executing an image forming process to be described later. The RAM 50D stores various data. The ASIC 50 </ b> B generates various control signals to be output to each part of the recording apparatus 10.

  Here, the recording device 10 scans and moves in the scanning direction (in the direction of arrow X in FIG. 1) by the scanning movement of the carriage 24 by the carriage drive unit 60, and ink droplets from the recording device 10 during the scanning movement in this scanning direction. By discharging, dots corresponding to ink droplets are formed along the scanning direction of the recording medium P.

  However, the ink droplets ejected from the nozzles of the recording head 26 moving in the scanning direction are the main droplets and the ink amount from the main droplets. It is known that the liquid droplets are divided into small sub-drops and adhere to the recording medium P. The main droplet is an ink droplet for forming dots ejected from the nozzle, and the sub-drop is the main droplet separated from the main droplet which is an ink droplet for forming dots ejected from the nozzle. Indicates a droplet with a smaller ink amount.

  Such sub-drops are generated due to the following causes. In other words, the ink droplets ejected from the nozzles of the recording head 26 that moves and scans toward the recording medium P in a shape that has a tail from the upstream side to the downstream side in the scanning direction (arrow X direction) of the recording head 26. Discharged. After that, the ink begins to form due to the aggregation of the ink due to surface tension at the tip of the ink droplet toward the recording medium P, and the ink that has not coalesced into the main droplet becomes a sub-drop. It flies toward the recording medium P while being separated into droplets. For this reason, on the recording medium P, main dots are recorded by the main droplets from the ink droplets ejected from the same nozzle, and by the sub-drops classified from the main droplets downstream of the main dots in the scanning direction. Sub-dots are recorded.

  FIG. 3 is a schematic diagram illustrating an example of the state of adhesion of the main dots recorded by the main droplets and the sub dots recorded by the sub droplets to the recording medium P. As shown in FIG. 3A, when the ink droplets are ejected while the recording head 26 is scanned and moved in the scanning forward direction (arrow XA direction) in the scanning direction, the ink droplets ejected from each nozzle are separated from the main droplet and the sub-droplet. Divided into drops. Then, on the recording medium P, the main dot M recorded by the main droplet and the sub dot recorded by the sub droplet separated from the main droplet downstream of the main dot M in the scanning forward direction (arrow XA direction). S is recorded. As shown in FIG. 3B, when the recording head 26 ejects ink droplets while scanning and moving in the scanning reverse direction (arrow XB direction) in the scanning direction, the droplets ejected from each nozzle are similarly , Divided into main and sub-drops. And on the recording medium P, the main dot M recorded by the main droplet, and the sub dot recorded by the sub droplet separated from the main droplet downstream of the main dot M in the scanning reverse direction (arrow XB direction). S is recorded.

  For this reason, when a plurality of dots are continuously recorded in the scanning direction (arrow X direction) of the recording head 26, the sub-dot corresponding to the upstream main dot in the scanning direction (arrow X direction) It is covered with another main dot formed adjacent to the downstream side of the main dot in the scanning direction. However, the sub-dots corresponding to the most downstream main dot in the scanning direction and the sub-dots corresponding to each discontinuous main dot in the scanning direction in the plurality of dots continuous in the scanning direction (arrow X direction) Since it is not covered with dots, it may cause image quality degradation.

  That is, as shown in FIG. 4, a plurality of image areas 72 are included in a print area 70 that is a range in the scan direction in a print range PA that is an area in which an image can be formed in the scan direction (arrow X direction) of the recording medium P. Assume that (image area 72A, image area 72B) exist. In FIG. 4, a range AB indicates a range in which the carriage 24 (that is, the recording head 26) can be scanned and moved in the scanning direction (arrow X direction).

  In this case, as shown in FIG. 5A, when the recording head 26 scans and moves in the scanning forward direction (arrow XA direction), the most downstream in the scanning forward direction in each of the image regions 72A and 72B. The sub dot corresponding to the main dot of the pixel on the side is not covered by the main dots of the other pixels. That is, the recording position of the main dot corresponding to the most downstream pixel in the scanning forward direction is an area 73 where the sub dot is not covered by the main dot of the other pixels. Similarly, as shown in FIG. 5B, when the recording head 26 scans and moves in the reverse scanning direction (the direction of the arrow XB), the most downstream in the scanning reverse direction in each of the image areas 72A and 72B. The sub dot corresponding to the main dot of the pixel on the side is not covered by the main dots of the other pixels. That is, the recording position of the main dot corresponding to the most downstream pixel in the reverse scanning direction is an area 73 where the sub dot is not covered by the main dot of another pixel.

  Therefore, conventionally, as shown in FIG. 6A, an area that is not covered by the sub-dots by other main dots is used as a boundary, and the sub-dots S corresponding to the main dots M recorded at the boundary are covered. Therefore, the process shown in FIG. 6B was performed. That is, as shown in FIG. 6B, conventionally, when forming the main dot M2 corresponding to the pixel at the boundary portion, when forming the other main dot M1 formed earlier than the main dot M2. The recording head 26 was scanned in the direction opposite to the scanning direction. Thus, conventionally, the sub-dot S2 generated at the boundary portion is recorded so as to overlap with the other main dot M1 formed earlier.

  However, in the prior art, it is necessary to reciprocate the recording head 26 for each dot group continuous in the scanning direction.

  Further, in the prior art, no processing is performed for the dots that are discontinuous in the scanning direction of the recording head 26, and therefore, as shown in FIG. A sub dot S corresponding to the main dot M was recorded.

  Further, in the prior art, when the recording head 26 is not reciprocally scanned for each dot group continuous in the scanning direction, the recording head is within the scan movable range AB in the scanning direction (arrow X direction) of the recording head 26. The scanning speed of 26 (sometimes referred to as a moving speed) was the maximum scanning speed that can be realized by the printing apparatus. FIG. 8 shows a position coordinate (with the origin as the position A) in the scanning movable range AB in the scanning direction (arrow X direction) of the carriage 24, that is, the recording head 26, and the carriage 24 (recording). The relationship with the scanning speed of the head 26) is shown. The speed of the carriage 24 is described as the carriage scanning speed Vc in FIG. Specifically, in the conventional recording apparatus, the recording head 26 is at the maximum speed from the position A toward the recording position of the dot corresponding to the most upstream pixel in the scanning forward direction (arrow XA direction) in the printing area 70. Accelerate toward the first speed V2. From there, the dots corresponding to the respective pixels in the print area 70 were recorded while maintaining the first speed V2 (see the diagram 76 in FIG. 8). For this reason, sub-dots that are not covered by the main dots are generated on the downstream side in the scanning direction of the recording head 26 in each of the image areas 72A and 72B.

  Therefore, in the recording apparatus 10 of the present embodiment, among the pixels that record dots in the image data, each of a pixel group composed of a plurality of pixels that are continuous in the scanning direction and a pixel that is discontinuous in the scanning direction Extract as In the recording apparatus 10, the pixel located at the most downstream side in the scanning direction of the recording head 26 in each of the extracted image regions is specified as a boundary pixel. Then, the scanning speed of the recording head 26 at the time of recording the dot corresponding to the boundary pixel is determined to a predetermined second speed lower than the first speed, and scanning at each position in the scanning direction of the recording head 26 is performed. The speed is determined and scan speed information is generated. Then, the recording apparatus 10 scans and moves the recording head 26 in the scanning direction based on the scanning speed information.

  As described above, the scanning direction indicates the direction in which the carriage 24, that is, the recording head 26 scans and moves (arrow X direction).

  The first speed is a speed predetermined by the recording apparatus 10 as a speed when ink is ejected from the recording head 26. As the first speed, for example, the maximum speed that can be realized by the recording apparatus 10 is set. The second speed is lower than the first speed, and the main dots recorded by the main droplets of the ejected ink droplets and the sub dots recorded by the sub droplets separated from the main droplets. The speed is equal to or lower than the speed at which the recording medium P is recorded in an overlapping manner and exceeds 0 speed. Note that the first speed and the second speed may be appropriately adjusted according to the apparatus configuration of the recording apparatus 10.

  The recording apparatus 10 of the present embodiment scans and moves the recording head 26 at the second speed when recording dots corresponding to boundary pixels. For this reason, as shown in FIG. 9, in the recording apparatus 10 of the present embodiment, when dots corresponding to the boundary pixels are recorded, the dots are recorded by the main dots recorded by the main droplets and the sub-droplets separated from the main droplets. The sub-dots can be overlaid and recorded. Therefore, the recording apparatus 10 can suppress deterioration in image quality due to sub-drops generated by ink droplet ejection.

  Hereinafter, the recording apparatus 10 of the present embodiment will be described in detail.

  FIG. 10 shows a functional block diagram in which the recording apparatus 10 is divided for each function realizing means determined based on hardware and software.

  As shown in FIG. 10, the control unit 50 includes an image data receiving unit 51, an image data reading unit 52, an image region extracting unit 53, a boundary specifying unit 54, a scanning speed determining unit 55, an interface 61, and a print control unit 57. I have.

  The image data receiving unit 51 receives image data from the external device via the interface 61. When the received image data is RGB data, the image data receiving unit 51 converts the received image data into YMCK image data. The image data includes pixel data that indicates the pixel position of each pixel and the density value (for example, 0 to 255) of each pixel for each pixel. Then, the image data receiving unit 51 executes so-called halftone processing or the like that converts the image data into image data having the number of gradations that can be recorded by the recording apparatus 10. In the following description, the image data after the halftone process is simply referred to as image data.

  Next, the image data reading unit 52 reads the YMCK image data processed by the image data receiving unit 51 and outputs the YMCK image data to the image region extraction unit 53 and the print control unit 57.

  The image area extracting unit 53 includes a pixel group that is continuous in the scanning direction (arrow X direction) of the recording head 26 among the pixels that record dots in the YMCK image data received from the image data reading unit 52, and a pixel group that is not aligned in the scanning direction. Each continuous pixel is extracted as an image region. Specifically, the image area extraction unit 53 extracts the image area from each image data of YMCK received from the image data reading unit 52.

  The boundary specifying unit 54 specifies, as a boundary pixel, a pixel located in the most downstream in the scanning direction (arrow X direction) of the recording head 26 in each of the YMCK image regions extracted by the image region extracting unit 53. Note that when the image region is composed of one pixel (discontinuous pixels in the scanning direction), the boundary specifying unit 54 specifies each of the discontinuous pixels as a boundary pixel. In the following, in order to simplify the description, image regions extracted from each image data of YMCK will be collectively referred to simply as image regions.

  In the image area, the pixel located on the most downstream side in the scanning direction (arrow X direction) of the recording head 26 is located on the most downstream side of the image area in the direction in which the recording head 26 scans and moves when ink droplets are ejected. The pixel to perform is shown.

  For example, as shown in FIG. 1, the ink droplets from the nozzles of the recording head 26 are moved only when the recording head 26 scans and moves in the scanning forward direction (arrow XA direction) in the scanning direction (arrow X direction) as shown in FIG. It is set as the structure which discharges. In this case, as shown in FIG. 5A, the boundary specifying unit 54 is located on the most downstream side in the scanning forward direction (arrow XA direction) in each image region 72 (image region 72A, image region 72B). A pixel is identified as a boundary pixel. That is, as shown in FIG. 5A, in each image area 72 (image area 72A, image area 72B), the pixel that records the dot in the most downstream area 73 in the scanning forward direction (arrow XA direction) It is specified as a pixel.

  On the other hand, as shown in FIG. 1, only when the recording head 26 is scanned and moved in the scanning reverse direction (arrow XB direction) in the scanning direction (arrow X direction), as shown in FIG. It is good also as a structure which discharges. In this case, as shown in FIG. 5B, the boundary specifying unit 54 is located on the most downstream side in the scanning reverse direction (arrow XB direction) in each image region 72 (image region 72A, image region 72B). Pixels are extracted as boundary pixels. That is, as shown in FIG. 5B, in each image area 72 (image area 72A, image area 72B), the pixel that records the dot in the most downstream area 73 in the scanning reverse direction (arrow XB direction) It is specified as a pixel.

  Note that the recording apparatus 10 changes the scanning direction (arrow X direction) of the recording head 26 in the scanning forward direction (arrow XA direction) according to the position of the recording medium P in the conveyance direction (arrow Y direction). Alternatively, a reciprocating scan may be alternately performed in the scanning reverse direction (arrow XB direction). In this case, the boundary specifying unit 54 first transports the recording medium P when the image area 72 is formed on the recording medium P for each pixel row in the scanning direction (arrow X direction) (arrow Y direction). ). The position of the recording medium P in the transport direction (arrow Y direction) for each pixel column along the scanning direction is obtained from the position coordinates indicated by the pixel data of each pixel in each image area 72. The boundary specifying unit 54 stores in advance information indicating the scanning forward direction or the scanning backward direction as the scanning direction of the recording head 26 corresponding to the position of the recording medium P in the transport direction. The information indicating the scan forward direction and the scan reverse direction is obtained by moving the recording head 26 in the scan forward direction (arrow XA direction) and the scan reverse direction (arrow XB direction) according to the position in the transport direction on the print medium P. What is necessary is just to predetermine according to the position in the conveyance direction of the recording medium P so that it may scan alternately. The boundary specifying unit 54 then displays information indicating the scanning forward direction or the scanning reverse direction according to the position in the transport direction (arrow Y direction) of the recording medium P in each of the image regions extracted by the image region extracting unit 53. The pixel located at the most downstream in the scanning direction (scanning forward direction or scanning reverse direction) read and read is specified as a boundary pixel.

  When the recording head 26 scans and moves in the scanning forward direction (arrow XA direction) in the same recording medium P as when the image is formed on the recording medium P, ink droplets are ejected from the nozzles of the recording head 26 or the recording medium When ink droplets are ejected from the nozzles of the recording head 26 when scanning is moved in the scanning reverse direction (arrow XB direction) within P, or when scanning movement is alternately performed in the scanning forward direction and scanning reverse direction on the recording medium P Information indicating whether ink droplets are ejected from the nozzles of the recording head 26 may be stored in advance in a memory such as the storage unit 56. The boundary specifying unit 54 may read the information from a memory such as the storage unit 56 to read the scanning movement direction of the recording head 26 when ink droplets are ejected and specify the boundary pixel.

  The information may be stored in advance in the storage unit 56 or may be input and stored in the storage unit 56 according to a scanning instruction of the operation unit 49 by the user.

  In the following, in order to simplify the description, the recording apparatus 10 scans and moves the recording head 26 in the scanning forward direction (arrow XA direction) on one recording medium P as shown in FIG. In the case where ink droplets are ejected from the nozzles of the recording head 26, and when the recording head 26 is scanned and moved in the scanning reverse direction (arrow XB direction) on the recording medium P, the ink droplets are ejected from the nozzles of the recording head 26. Although the case where it is set as the structure which discharges is demonstrated, it is not restricted to this form.

  Then, the boundary specifying unit 54 outputs the image data received from the image region extracting unit 53 and information indicating the specified boundary pixel to the scanning speed determining unit 55.

  The scanning speed determination unit 55 determines the scanning speed at each position in the scanning direction of the recording head 26 (carriage 24) when dots corresponding to each pixel of each image area included in the image data are formed. Specifically, the scanning speed determination unit 55 determines the scanning speed of the recording head 26 at the time of recording the dots corresponding to the boundary pixels to a second speed that is lower than the first speed, and also scan direction (arrow X The scanning speed of the recording head 26 corresponding to each position in the scan movable range AB of the recording head 26 in the direction) is determined, and scanning speed information is generated. That is, the scanning speed determination unit 55 determines the scanning speed of the recording head 26 when forming dots corresponding to each pixel of each image area included in the image data.

  The storage unit 56 stores in advance information indicating the first speed and the second speed. As the information indicating the first speed, information indicating the maximum speed at which dots can be formed by ejecting ink droplets from the recording head 26 in the recording apparatus 10 is determined as described above. The first speed may be set in advance according to the apparatus configuration of the recording apparatus 10 and stored in the storage unit 56. As described above, the second speed is slower than the first speed, and is recorded by the main dots recorded by the main droplets of the ejected ink droplets and the sub-drops separated from the main droplets. The sub-dots to be recorded are at a speed equal to or lower than the speed at which the sub-dots are recorded on the recording medium P and exceed the speed 0. The first speed and the second speed may be measured in advance by the apparatus configuration of the recording apparatus 10 and stored in the storage unit 56 in advance. Further, the first speed and the second speed stored in the storage unit 56 may be changed by an operation instruction of the operation unit 49 by the user.

  The scanning speed determination unit 55 is based on the first speed and the second speed stored in the storage unit 56, the image data received from the boundary specifying unit 54, and information indicating the specified boundary pixel, Scan speed information is generated.

  Specifically, the scanning speed determining unit 55 scans and moves the recording head 26 at the first speed when recording dots corresponding to the boundary pixels, and from the first speed on the upstream side in the scanning direction of the boundary pixels. The scanning speed of the recording head 26 at the time of recording the dot corresponding to each pixel of each image area is determined so as to reduce the scanning speed toward the second speed. The scanning speed determination unit 55 uses a predetermined value as the deceleration rate. For example, the deceleration rate may be determined by measuring in advance a deceleration rate that can be realized by the recording head 26.

  For example, as shown in FIG. 4, a plurality of image regions 72 (image region 72A and image region 72B) are included in a print region 70 that is an image-forming region in the scanning direction (arrow X direction) of the recording medium P. Suppose it exists. Then, as shown in FIG. 5A, the recording head 26 scans and moves in the scanning forward direction (arrow XA direction), and in each of the image regions 72A and 72B, the region 73 on the most downstream side in the scanning forward direction. Are set as boundary pixels.

  In this case, an example of the scanning speed information determined by the scanning speed determination unit 55 is shown in FIG. FIG. 11 shows the position of the recording head 26 in the scanning movable range AB in the scanning direction (arrow X direction) when ejecting ink droplets while scanning the recording head 26 in the scanning forward direction (arrow XA direction). FIG. 6 is a schematic diagram showing a relationship between coordinates (position A is an origin) and a scanning speed of a carriage 24 (recording head 26).

As shown in FIG. 11, for example, the scanning speed determination unit 55 creates scanning speed information indicating the following fluctuations in scanning speed. For example, from the position A which is the most upstream position in the scanning forward direction in the scanning movable range AB in the scanning direction of the recording head 26 to the most upstream position in the scanning forward direction of the print area 70 from the speed 0 to the first. Accelerate to speed V2. The acceleration rate at this time is a predetermined acceleration rate. Then, while maintaining the first velocity V2, the recording head 26 is scanned and moved toward the downstream side in the scanning forward direction, and at the time of dot recording (position) corresponding to the most downstream boundary pixel in the scanning forward direction of the image region 72A. 73A ₁ ), the scanning speed is reduced at a predetermined deceleration rate so that the scanning speed of the recording head 26 becomes the second speed V1. Then, the scanning speed of the recording head 26 is again accelerated at the acceleration rate toward the first speed V2. Then, the deceleration rate of the scanning speed of the recording head 26 during recording of dots corresponding to the most downstream of the boundary pixels in the scanning order direction of the image area 72B (see position 73B ₁₎ is predetermined such that the second speed V1 To reduce the scanning speed. Then, the scanning speed of the recording head 26 is accelerated again at the acceleration rate toward the first speed V2, and then decelerated toward the position B at the deceleration rate. In other words, the scanning speed determination unit 55 creates the scanning speed information indicated by the diagram 74 in FIG. 11, for example.

  On the other hand, as shown in FIG. 5B, the recording head 26 scans and moves in the scanning reverse direction (arrow XB direction), and the most downstream area 73 in the scanning reverse direction in each of the image areas 72A and 72B. Are set as boundary pixels.

  An example of the scanning speed information determined by the scanning speed determination unit 55 in this case is shown in FIG. FIG. 12 shows the position of the print head 26 in the scan movable range AB in the scan direction (arrow X direction) when ejecting ink droplets while scanning the print head 26 in the scan reverse direction (arrow XB direction). FIG. 6 is a schematic diagram showing a relationship between coordinates (position A is an origin) and a scanning speed of a carriage 24 (recording head 26).

As shown in FIG. 12, for example, the scanning speed determination unit 55 creates scanning speed information indicating the following fluctuations in scanning speed. For example, from the position B, which is the most upstream position in the scanning reverse direction in the scanning movable range AB in the scanning direction of the recording head 26, from the speed 0 toward the first upstream position in the scanning reverse direction in the printing region 70. Accelerate to speed V2. The acceleration rate at this time is a predetermined acceleration rate. Then, while maintaining the first velocity V2, the recording head 26 is scanned and moved downstream in the reverse scanning direction, and at the time of dot recording (position) corresponding to the most downstream boundary pixel in the reverse scanning direction of the image region 72B. as the scanning speed of the recording head 26 of 73B reference ₂₎ is a second speed V1, decelerating the scanning velocity at a predetermined deceleration rate. Then, the scanning speed of the recording head 26 is again accelerated at the acceleration rate toward the first speed V2. Then, the deceleration rate of the scanning speed of the recording head 26 during recording of dots corresponding to the most downstream of the boundary pixels in the scanning order direction of the image region 72A (see position 73A ₂₎ is predetermined such that the second speed V1 To reduce the scanning speed. Further, after again accelerating the scanning speed of the recording head 26 toward the first speed V2 at the acceleration rate, the recording head 26 is decelerated toward the position A at the deceleration rate. That is, the scanning speed determination unit 55 creates, for example, scanning speed information indicated by a diagram 75 in FIG.

  Returning to FIG. 10, the description will be continued. The scanning speed determination unit 55 generates scanning speed information by determining the scanning speed of the recording head 26 corresponding to each position in the scanning movable range AB of the recording head 26 in the scanning direction (arrow X direction). To do. Then, the scanning speed determination unit 55 outputs scanning speed information indicating the determined scanning speed to the print control unit 57.

  The print control unit 57 receives the image data processed by the image data receiving unit 51 and receives scanning speed information from the scanning speed determination unit 55. The print control unit 57 controls the recording head 26 based on the received image data, and controls the carriage driving unit 60 and the conveyance driving unit 62 based on the scanning speed information.

  Specifically, the print controller 57 includes a scanning speed controller 57A, a transport position controller 57B, and a recording head drive controller 57C. The recording head drive control unit 57C converts the image data received from the image data reading unit 52 into a data structure that can be decoded by the recording head 26, and rearranges the data in the recording order (transfer order). The recording head drive control unit 57C outputs the recording data generated by this rearrangement to the recording head 26. At this time, the recording head drive control unit 57C rearranges the data in consideration of the ejection timing and the data array mapped to the recording head 26 and the nozzle array of the recording head 26, and outputs the data to the recording head 26 as recording data. .

  The scanning speed control unit 57A controls the carriage driving unit 60 via the carriage motor driver 58 in accordance with the scanning speed information received from the scanning speed determination unit 55. Specifically, the scanning speed control unit 57A synchronizes with a signal corresponding to each pixel data transmitted from the recording head drive control unit 57C to the recording head 26, and at each pixel dot at a speed indicated by the scanning speed information. The carriage drive unit 60 is controlled so as to be recorded. The transport position control unit 57B controls the transport drive unit 62 via the transport motor driver 64 in synchronization with a signal corresponding to each pixel data transmitted from the print head drive control unit 57C to the print head 26.

  Next, details of the image forming process in the recording apparatus 10 according to the present embodiment will be described.

  FIG. 13 is a flowchart showing the overall flow of the image forming process in the present embodiment.

  First, the image data reading unit 52 reads the image data received by the image data receiving unit 51 (step S100). Next, the image area extraction unit 53 extracts an image area in the image data (step S102). Next, the boundary specifying unit 54 specifies boundary pixels in the extracted image region (step S104). Next, the scanning speed determination unit 55 determines the scanning speed and generates scanning speed information (step S106). Then, the print control unit 57 controls the carriage driving unit 60, the conveyance driving unit 62, and the recording head 26, and performs a printing process for forming an image on the recording medium P (step S108).

  When the recording apparatus 10 executes the image forming process, in the recording apparatus 10 of the present embodiment, the scanning direction (arrow X direction) of the recording head 26 (carriage 24) among the pixels that record dots in the image data. A pixel corresponding to the most downstream dot in the scanning direction in a plurality of consecutive dots and a pixel corresponding to a discontinuous dot in the scanning direction are specified as boundary pixels. The recording apparatus 10 scans and moves the recording head 26 at a predetermined second speed that is lower than the first speed when recording dots corresponding to the boundary pixels. The second speed is lower than the first speed, and is equal to or lower than the speed at which the sub-droplet is recorded on the main drop (dot) corresponding to the sub-droplet.

  For this reason, at the time of recording the dot corresponding to the boundary pixel, the sub dot by the sub droplet separated from the main droplet of the ink droplet ejected from the nozzle of the recording head 26 is superimposed on the main dot of the main droplet in the ink droplet. The recording head 26 scans and moves in the scanning direction (in the direction of arrow X) at the speed that is set. Specifically, as described with reference to FIG. 9, in the recording apparatus 10 of the present embodiment, the sub dot S corresponding to the main dot M, which is the dot corresponding to the boundary pixel, is changed to the main dot corresponding to the sub dot S. It is possible to record over the dots M.

  Therefore, the recording apparatus 10 according to the present embodiment can suppress image quality deterioration caused by sub-drops generated by ink droplet ejection.

  In addition, the image area extraction unit 53 extracts, as image areas, pixel groups that are continuous in the scanning direction (arrow X direction) and discontinuous pixels in the main scanning direction (arrow X direction) in the image data. . Then, the scanning speed determination unit 55 scans and moves the recording head 26 (carriage 24) at the second speed at the time of recording the dot corresponding to the boundary pixel, and the first speed on the upstream side in the scanning direction of the boundary pixel. The scanning speed of the recording head 26 is determined so as to decelerate the scanning speed toward the second speed.

  For this reason, for example, the recording head 26 (carriage 24) is scanned in the scanning forward direction (arrow XA direction), ink droplets are ejected, and one dot (one pixel) interval discontinuously in the scanning direction (arrow X direction). It is assumed that dots corresponding to a plurality of pixels are recorded discontinuously with a gap. In this case, as shown in FIG. 14A, the scanning speed during recording of dots corresponding to each of the plurality of discontinuous pixels is the second speed V1, and between the dots, the scanning speed is the first speed V2. The scanning speed of the recording head 26 is determined so as to decelerate toward the second speed V1 after acceleration. Therefore, when dots corresponding to a plurality of pixels are recorded discontinuously at intervals of one dot (one pixel) in the scanning direction (arrow X direction), the scanning speed determination unit 55 sets The carriage drive unit 60 is scanned at the scanning speed, and the recording head 26 held by the carriage 24 is scanned and moved, so that the recording head 26 is moved at the scanning speed shown by the wave diagram 76 as shown in FIG. Move scanning. Therefore, the sub dot S separated from the main dot M corresponding to each pixel discontinuous in the scanning direction becomes the main dot M of the main droplet corresponding to the sub dot S (which is the separation source of the sub dot S). It is recorded repeatedly.

  Therefore, in the recording apparatus 10 of the present embodiment, it is possible to suppress image quality deterioration caused by sub-drops generated by ink droplet ejection.

  Further, also in the case of so-called borderless printing in which the area extending from one end to the other end in the scanning direction on the recording medium P is used, the image quality deterioration due to the sub-drops generated by ink droplet ejection is suppressed. be able to. In this case, as the image data, for example, image data including pixels that record dots at the ends in the scanning direction may be used.

  In the present embodiment, the case where the scanning speed of the recording head 26 (carriage 24) at the time of recording the dot corresponding to the boundary pixel is set to the second speed regardless of the size of the formed dot has been described. . However, the speed of the carriage 24 (recording head 26) may be adjusted according to the size of the dot corresponding to the boundary pixel.

  In this case, for example, the storage unit 56 associates information indicating the size of the dot corresponding to the boundary pixel, that is, the amount of ejected ink droplets, with information indicating the scanning speed of the recording head 26. And remember. The information indicating the scanning speed of the recording head 26 includes the second speed described above, that is, the speed at which the sub-dots corresponding to the main dots are recorded on the main dots while being slower than the first speed. If it is in the range. Then, the scanning speed determination unit 55 may determine a higher scanning speed toward the second speed as the amount of ink droplets increases.

  Specifically, each pixel data included in the halftone processed image data indicated by the number of gradations that can be recorded by the recording apparatus 10 indicates three types of large droplets, medium droplets, and small droplets. In this case, information indicating the scanning speed corresponding to the size of each droplet (dot) so as to increase from the small droplet toward the large droplet having a larger amount of ink toward the second velocity. The information indicating the amount of ink droplets (large droplets, medium droplets, small droplets) may be stored in association with each other. Then, the scanning speed determination unit 55 creates the scanning speed information by reading information indicating the scanning speed corresponding to the information indicating the amount of ink droplets indicated by the pixel data corresponding to the boundary pixel from the storage unit 56. That's fine.

  In this way, the scanning speed of the carriage 24 (recording head 26) can be adjusted according to the size of the main dot corresponding to the boundary pixel, and efficient printing processing becomes possible.

  In the present embodiment, the second speed is described as being lower than the first speed and higher than the speed 0. However, the second speed may be information indicating the speed 0.

  By doing so, in the recording apparatus 10, the scanning movement of the carriage 24 (recording head 26) is stopped when the dots corresponding to the boundary pixels are recorded. For this reason, it is possible to further suppress the sub-dots from being recorded at positions deviating from the main dots, and to further suppress the image quality deterioration due to the sub-drops.

  In the present embodiment, as shown in FIG. 14A, the scanning speed when recording dots corresponding to each of a plurality of discontinuous pixels in the scanning direction (arrow X direction) is the second speed V1. In addition, a case has been described in which the scanning speed of the recording head 26 is determined so as to accelerate toward the first speed V2 and then decelerate toward the second speed V1 between the dots.

  However, in the recording apparatus 10 of the present embodiment, as shown in FIG. 14B, the scanning speed is the second when recording dots corresponding to each of a plurality of discontinuous pixels in the scanning direction (arrow X direction). The speed V1 may be set, and the second speed V1 may be maintained even between the dots corresponding to the discontinuous pixels (in FIG. 14-2, refer to the diagram 81). For example, when the distance between dots corresponding to each of a plurality of pixels discontinuous in the scanning direction (arrow X direction) is equal to or smaller than a predetermined interval, a plurality of discontinuous pieces in the scanning direction (arrow X direction). The scanning speed becomes the second speed V1 when dots corresponding to the respective pixels are recorded, and the second speed V1 may be maintained even between the dots corresponding to these discontinuous pixels. The information indicating the predetermined interval may be stored in the storage unit 56 in advance, or may be input and stored in the storage unit 56 according to an operation instruction of the operation unit 49 by the user.

(Second Embodiment)
In the first embodiment, when recording dots corresponding to each of discontinuous pixels in the scanning direction of the carriage 24 (recording head 26), the recording head 26 is decelerated to the second speed, and between the dots, A case has been described in which acceleration is performed from the second speed toward the first speed and deceleration is performed from the first speed to the second speed.

  In the present embodiment, after the recording head 26 is scanned and moved at the first speed during the recording of dots corresponding to the boundary pixels, the boundary pixels after a predetermined interval are recorded at the second speed. The head 26 is moved by scanning.

  FIG. 15 is a functional block diagram in which the recording apparatus 10 </ b> A according to the present embodiment is divided for each function realization means determined based on hardware and software. As shown in FIG. 15, the recording apparatus 10A of the present embodiment includes an operation unit 49, an interface 61, a detection unit 48, a control unit 51A, a carriage motor driver 58, a carriage drive unit 60, a conveyance motor driver 64, and a conveyance drive unit. 62 and the recording head 26. The control unit 51A includes an image data receiving unit 51, an image data reading unit 52, an image region extracting unit 53, a boundary specifying unit 54A, a scanning speed determining unit 55A, a storage unit 56, and a print control unit 57. The recording apparatus 10A according to the present embodiment includes a control unit 51A including a boundary specifying unit 54A and a scanning speed determining unit 55A instead of the control unit 50 including the boundary specifying unit 54 and the scanning speed determining unit 55. Other than this, the configuration is the same as that of the recording apparatus 10 of the first embodiment. For this reason, only different parts will be described in detail.

  In the present embodiment, the storage unit 56 further stores information indicating the speed adjustment interval in addition to the first speed and the second speed. The information indicating the speed adjustment interval indicates the minimum interval from when the scanning speed of the carriage 24 (recording head 26) is changed to the second speed to the second speed. Examples of the information indicating the speed adjustment interval include 5 dots and 7 dots.

  Information indicating the speed adjustment interval may be stored in the storage unit 56 in advance, or may be input to the operation unit 49 by the user according to an operation instruction and stored in the storage unit 56.

  The boundary specifying unit 54A specifies, as a boundary pixel, a pixel located at the most downstream side in the scanning direction (arrow X direction) of the recording head 26 in each of the YMCK image regions extracted by the image region extracting unit 53. When the image area is composed of one pixel (discontinuous pixels in the scanning direction), the boundary specifying unit 54A has the discontinuous pixels arranged in the scanning direction at intervals in the scanning direction. It is determined whether or not. When the discontinuous pixels are not arranged at intervals in the scanning direction, the boundary specifying unit 54A performs the same process as the boundary specifying unit 54 in the first embodiment.

  On the other hand, when the discontinuous pixels are arranged at intervals in the scanning direction, the boundary specifying unit 54A uses the information indicating the speed adjustment interval among the plurality of discontinuous pixels in the scanning direction. Each pixel at a position spaced apart from each other is specified as a boundary pixel.

  Then, the scanning speed determination unit 55A is based on the first speed and the second speed stored in the storage unit 56, the image data received from the boundary specifying unit 54A, and the information indicating the boundary pixel. Similarly to the scanning speed determination unit 55 of the first embodiment, the scanning speed information is generated. That is, the scanning speed determination unit 55A determines the scanning speed of the recording head 26 at the time of recording the dots corresponding to the boundary pixels to the second speed that is lower than the first speed, and in the scanning direction (arrow X direction). The scanning speed of the recording head 26 corresponding to each position in the scan movable range AB of the recording head 26 is determined, and scanning speed information is generated.

  Here, the information indicating the boundary pixel received from the boundary specifying unit 54A is the scanning direction when a plurality of discontinuous pixels in the scanning direction as the image region are arranged at intervals in the scanning direction. Among the plurality of discontinuous pixels, pixels located at predetermined speed adjustment intervals in the scanning direction are specified as boundary pixels.

  For this reason, when a plurality of discontinuous pixels are arranged in the scanning direction, the scanning speed information generated by the scanning speed determination unit 55A corresponds to the speed adjustment interval instead of all the discontinuous pixels. Each pixel is generated so that the scanning speed of the recording head 26 at the time of recording the dot corresponding to each pixel becomes the second speed.

  FIG. 16 shows an example of scanning speed information determined by the scanning speed determination unit 55A. FIG. 16 shows the position coordinates of the carriage 24, that is, the recording head 26 in the scanning direction (arrow X direction) and the carriage 24 when ejecting ink droplets while moving the recording head 26 in the scanning forward direction (arrow XA direction). An example of the relationship with the scanning speed of the (recording head 26) is shown.

  For example, as shown in FIG. 16, the recording head 26 scans in the scanning forward direction (arrow XA direction) and records dots corresponding to a plurality of discontinuous pixels at intervals in the scanning direction. As information indicating the speed adjustment interval, for example, information indicating 5 dots is stored in the storage unit 56.

  In this case, for example, as shown in FIG. 16, the scanning speed determination unit 55A creates scanning speed information indicating the following fluctuations in scanning speed. For example, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, the second velocity V1 is set when the dot corresponding to the pixel located in the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26 is recorded. Thus, the speed of the recording head 26 (carriage 24) is determined. Next, acceleration is performed at a predetermined acceleration rate from the second speed V1 toward the first speed V2 toward the downstream side in the scanning forward direction, and the first speed V2 is maintained. Then, it is decelerated at a predetermined deceleration rate so that the second speed V1 is obtained when a dot at a position separated by a speed adjustment interval (for example, 5 dots) from the dot corresponding to the pixel located at the uppermost stream is recorded. In other words, the scanning speed determination unit 55A creates the scanning speed information indicated by the line 77 in FIG. 16, for example.

  For this reason, as shown in FIG. 16, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, the dot corresponding to the pixel located at the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26 The dots recorded on the downstream side in the scanning direction with a speed adjustment interval (for example, 5 dots) from the dots are recorded by the recording head 26 that scans and moves at the second speed V1. Therefore, in these dots, the sub dot S1 is recorded so as to overlap the main dot M1, and the sub dot S4 is recorded so as to overlap the main dot M4. On the other hand, dots recorded between these dots are recorded by the recording head 26 that scans and moves at a speed higher than the second speed. For this reason, the dots recorded between these dots are formed at positions where the main dot and the sub dot are separated from each other (see main dot M2 and sub dot S2, main dot M3 and sub dot S3 in FIG. 16). . However, in the recording apparatus 10A of the present embodiment, it is possible to realize high-speed printing as compared to the first embodiment while suppressing image quality deterioration due to sub-droplets.

  Also, for example, as shown in FIG. 17, the recording head 26 scans in the scanning forward direction (arrow XA direction) and corresponds to a plurality of discontinuous pixels at intervals in the scanning direction (for example, at intervals of 5 dots). Record the dots to be used. As information indicating the speed adjustment interval, for example, information indicating 7 dots is stored in the storage unit 56.

  In this case, for example, as shown in FIG. 17, the scanning speed determination unit 55A creates scanning speed information indicating the following fluctuations in scanning speed. For example, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, the second velocity V1 is set when the dot corresponding to the pixel located in the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26 is recorded. Thus, the speed of the recording head 26 (carriage 24) is determined. Next, acceleration is performed at a predetermined acceleration rate from the second speed V1 toward the first speed V2 toward the downstream side in the scanning forward direction, and the first speed V2 is maintained. Then, it is decelerated at a predetermined deceleration rate so that the second speed V1 is obtained when a dot at a position separated from the dot corresponding to the pixel located at the uppermost stream by a speed adjustment interval (for example, 7 dots) is recorded. That is, the scanning speed determination unit 55A creates, for example, scanning speed information indicated by a diagram 78 in FIG.

  For this reason, as shown in FIG. 17, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, the dot corresponding to the pixel located in the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26 The dots recorded on the downstream side in the scanning direction at a speed adjustment interval (for example, 7 dots) from the dots are recorded by the recording head 26 that scans and moves at the second speed V1. Therefore, in these dots, the sub dot S1 is recorded over the main dot M1, and the sub dot S7 is recorded over the main dot M7. On the other hand, dots recorded between these dots are recorded by the recording head 26 that scans and moves at a speed higher than the second speed V1. For this reason, the dots recorded between these dots are formed at positions where the main dot and the sub dot are separated (see main dot M2 and sub dot S2, main dot M3 and sub dot S3 in FIG. 17). . However, in the recording apparatus 10A of the present embodiment, it is possible to realize high-speed printing as compared to the first embodiment while suppressing image quality deterioration due to sub-droplets.

  As described above, as shown in the diagram 76 of FIG. 14A described in the first embodiment, the ink droplets are ejected from the recording head 26 by decelerating to the second speed V1 for each dot. Thus, in the recording apparatus 10A of the present embodiment, the number of times of deceleration of the recording head 26 to the second speed V1 is reduced as compared with the case where dots are recorded.

  Therefore, in the recording apparatus 10A of the present embodiment, it is possible to realize high-speed image formation while suppressing image quality deterioration due to sub-droplets.

  When the information indicating the speed adjustment interval stored in the storage unit 56 is “0”, the scanning speed determination unit 55A performs the same process as the scanning speed determination unit 55 described in the first embodiment. What should I do?

(Third embodiment)
In the first embodiment, the case where the boundary specifying unit 54 specifies boundary pixels in each of the YMCK image areas extracted from each of the YMCK image data has been described. In the first embodiment, the scanning speed determination unit 55 scans and moves the recording head 26 at the second speed when recording the dots corresponding to the boundary pixels of the specified image areas of YMCK. The case of creating scanning speed information has been described.

  In the present embodiment, an image area is extracted from image data of an image recorded with ink having a color absorption rate greater than or equal to a predetermined value, and a dot corresponding to a boundary pixel of the image area is extracted. A case where the recording head 26 is scanned and moved at the second speed during recording will be described.

  FIG. 18 is a functional block diagram in which the recording apparatus 10B according to the present embodiment is divided for each function realization means determined based on hardware and software. As shown in FIG. 18, the recording apparatus 10B according to the present embodiment includes an operation unit 49, an interface 61, a detection unit 48, a control unit 51B, a carriage motor driver 58, a carriage drive unit 60, a conveyance motor driver 64, and a conveyance drive unit. 62 and the recording head 26. The control unit 51B includes an image data receiving unit 51, an image data reading unit 52, an image region extracting unit 53B, a boundary specifying unit 54B, a scanning speed determining unit 55B, a storage unit 56, and a print control unit 57. The recording apparatus 10B according to the present embodiment replaces the control unit 50 including the image region extraction unit 53, the boundary specification unit 54, and the scanning speed determination unit 55 with an image region extraction unit 53B, a boundary specification unit 54B, The configuration is the same as that of the recording apparatus 10 of the first embodiment except that the controller 51B includes the scanning speed determination unit 55B. Therefore, different parts will be described in detail.

  In the present embodiment, in addition to the first speed and the second speed, the storage unit 56 stores in advance information indicating the color to be adjusted for the scanning speed of the carriage 24 (recording head 26). Examples of the color to be adjusted include a color whose visible light absorption rate is equal to or greater than a predetermined value. Specifically, it is assumed that four color inks of CMYK are used as a plurality of ink colors recorded by the recording head 26. In this case, for example, information indicating black, which has a higher light absorption rate of visible light than CMY, is stored in the storage unit 56 as information indicating the color to be adjusted.

  The information indicating the color to be adjusted may be stored in advance in the storage unit 56, or may be input to the operation unit 49 by the user according to an operation instruction and stored in the storage unit 56. The information indicating the adjustment target color is not limited to black.

  The image region extraction unit 53B reads image data of a color corresponding to information indicating the color to be adjusted stored in the storage unit 56 among the YMCK image data received from the image data reading unit 52. For example, the image area extraction unit 53B reads K (black) image data, and continuously prints the dots in the K image data in the scanning direction (arrow X direction) of the recording head 26 (carriage 24). Each of the pixel group to be performed and pixels discontinuous in the scanning direction are extracted as an image region.

  The boundary specifying unit 54B specifies the pixel located at the most downstream side in the scanning direction (arrow X direction) in each of the K image regions extracted by the image region extracting unit 53B as the boundary pixel. Note that, when the image region is composed of one pixel (discontinuous pixels in the scanning direction), the boundary specifying unit 54B specifies each of the discontinuous pixels as a boundary pixel. The boundary pixel specifying method by the boundary specifying unit 54B is the same as the boundary specifying unit 54 of the first embodiment.

  The scanning speed determination unit 55B determines the scanning speed of the recording head 26 (carriage 24) when forming dots corresponding to each pixel of each image area included in the K (black) image data in the first embodiment. This is determined in the same manner as the scanning speed determination unit 55.

  For this reason, the recording apparatus 10B of the present embodiment adjusts the scanning speed of the recording head 26 (carriage 24) when recording dots of a color whose light absorption rate of visible light is equal to or higher than a predetermined light absorption rate, The scanning movement is performed at the second speed when the dot of the boundary pixel is recorded.

  For this reason, for example, the recording head 26 (carriage 24) is scanned in the scanning forward direction (arrow XA direction), ink droplets are ejected, and one dot (one pixel) interval discontinuously in the scanning direction (arrow X direction). It is assumed that dots corresponding to a plurality of pixels are recorded discontinuously with a gap. In this case, as shown in FIG. 19A, when the color of the dot to be recorded is black, the scanning speed at the time of recording the dot corresponding to each of the plurality of discontinuous pixels is the second speed. The scanning speed of the recording head 26 is determined so as to be V1. For this reason, as shown in FIG. 19A, for the black dots, the sub-dots S corresponding to the main dots M are recorded so as to overlap the main dots M.

  On the other hand, in the present embodiment, when the dots to be recorded are, for example, yellow, the scanning speed of the recording head 26 is not adjusted. For example, the scanning speed of the recording head 26 is set to the first speed V2. It is determined. For this reason, as shown in FIG. 19B, for yellow dots, sub-dots S corresponding to the main dots M are recorded at locations different from the main dots M.

  Also, in the case where dots of different colors are recorded on the same pixel row in the scanning direction, the recording head 26 (carriage 24) is used when recording dots of a color whose visible light absorption is equal to or greater than a predetermined light absorption. The scanning speed is adjusted, and the scanning movement is performed at the second speed when the dot of the boundary pixel is recorded.

  For this reason, for example, the recording head 26 (carriage 24) is scanned in the scanning forward direction (arrow XA direction), ink droplets are ejected, and one dot (one pixel) interval discontinuously in the scanning direction (arrow X direction). To record dots of different colors. In this case, when the color of the dot to be recorded is black, the scanning speed of the recording head 26 is determined so that the scanning speed at the time of dot recording becomes the second speed V1. Further, when the dot to be recorded has a color other than black (for example, yellow), the scanning speed of the recording head 26 is determined so that the scanning speed at the time of dot recording is the first speed V2. For this reason, as shown in FIG. 20, with respect to the black dots, the sub dots SB corresponding to the main dots MB are recorded so as to overlap the main dots MB. And about the yellow dot, the sub dot SY corresponding to each main dot MY is recorded in the position different from the main dot MY.

  As described above, in the recording apparatus 10B of the present embodiment, the scanning speed of the recording head 26 (carriage 24) is not adjusted when recording dots of a color whose visible light absorption is less than a predetermined value. When recording a dot having a color with a light absorption rate equal to or greater than a predetermined value, the scanning speed of the recording head 26 is adjusted.

  Dots having a light absorption rate less than a predetermined value (for example, yellow) have less influence on image quality than dots having a high light absorption rate such as black. Therefore, in the recording apparatus 10B of the present embodiment, it is possible to improve the printing speed and suppress image quality deterioration due to the sub-droplet generated by the ink droplet discharge.

(Fourth embodiment)
In the first embodiment, the pixel located at the most downstream side in the scanning direction of the recording head 26 in the pixel group (image region) continuous in the scanning direction of the recording head 26 is specified as the boundary pixel. The case where the recording head 26 is scanned and moved at a predetermined second speed lower than the first speed when recording dots corresponding to the boundary pixels has been described.

  In the present embodiment, among the pixel groups that are included in the image data and that are continuous in the scanning direction, a pixel group that is continuous in a predetermined number or more is extracted as an image area, and the recording head 26 in the scanning direction in the image area is extracted. The case where the pixel located at the most downstream is specified as the boundary pixel will be described.

  FIG. 21 is a functional block diagram in which the recording apparatus 10 </ b> C according to the present embodiment is divided for each function realization means determined based on hardware and software. As shown in FIG. 21, the recording apparatus 10C of the present embodiment includes an operation unit 49, an interface 61, a detection unit 48, a control unit 51C, a carriage motor driver 58, a carriage driving unit 60, a conveyance motor driver 64, and a conveyance driving unit. 62 and the recording head 26. The control unit 51C includes an image data receiving unit 51, an image data reading unit 52, an image region extracting unit 53C, a boundary specifying unit 54C, a scanning speed determining unit 55C, a storage unit 56, and a print control unit 57. The recording apparatus 10C of the present embodiment replaces the control unit 50 including the image region extraction unit 53, the boundary specification unit 54, and the scanning speed determination unit 55 with an image region extraction unit 53C, a boundary specification unit 54C, The configuration is the same as that of the recording apparatus 10 of the first embodiment except that the controller 51C includes the scanning speed determination unit 55C. For this reason, only different parts will be described in detail.

  In the present embodiment, in addition to the first speed and the second speed, the storage unit 56 further stores information indicating the number of continuations subject to speed adjustment in a pixel group that is continuous in the scanning direction. The information indicating the number of continuous objects to be speed adjusted indicates the number of continuous pixels to be adjusted for the scanning speed of the recording head 26 to the second speed when a plurality of dots are recorded in the scanning direction. .

  Information indicating the number of consecutive speed adjustment targets may be stored in the storage unit 56 in advance, or may be input to the operation unit 49 by the user according to an operation instruction and stored in the storage unit 56.

  The image area extracting unit 53C converts each pixel discontinuous in the scanning direction (arrow X direction) of the recording head 26 from the pixels that record dots in the YMCK image data received from the image data reading unit 52. Extract as Further, the image area extraction unit 53C extracts a pixel group that is continuous in the scanning direction (arrow X direction) of the recording head 26 from the pixels that record dots in the YMCK image data received from the image data reading unit 52, Among the extracted pixel groups, a pixel group in which pixels equal to or greater than a predetermined number (the number of consecutive speed adjustment targets) is extracted as an image region.

  The boundary specifying unit 54C sets the pixel located in the most downstream in the scanning direction (arrow X direction) in each of the YMCK image regions extracted by the image region extracting unit 53C, as the boundary specifying unit 54 in the first embodiment. In the same manner as described above, it is specified as a boundary pixel. Here, among the image areas output from the image area extraction unit 53C to the boundary specifying unit 54C, an image area indicating a pixel group that is continuous in the scanning direction has a predetermined number (the number of continuous speed adjustment targets). ) A pixel group in which pixels are continuous. For this reason, out of the pixel groups that are continuous in the scanning direction, a pixel group that is continuous with less than the predetermined number of pixels is not subject to deceleration adjustment to the second speed.

  Then, similarly to the scanning speed determining unit 55 in the first embodiment, the scanning speed determining unit 55C is configured so that each position in the scanning movable range AB in the scanning direction (arrow X direction) of the recording head 26 is obtained. The scanning speed of the recording head 26 corresponding to is determined, and scanning speed information is generated.

  FIG. 22 shows an example of dots formed when the carriage 24 (recording head 26) scans and moves based on the scanning speed information determined by the scanning speed determination unit 55C. For example, it is assumed that information indicating 4 dots is stored in the storage unit 56 as information indicating the number of continuous speed adjustment targets.

  In this case, the scanning speed determination unit 55C sets the scanning speed of the recording head 26 to the first speed for an image area in which the number of pixels continuous in the scanning direction is less than four. Then, the scanning speed determination unit 55C, for an image region in which the number of pixels continuous in the scanning direction is 4 or more, the most downstream pixel in the scanning direction of the recording head 26 (for example, the scanning forward direction (arrow XA direction)). The scanning speed at the time of recording dots corresponding to is set to the second speed.

  For this reason, for example, as shown in FIG. 22 (A), for an image region that is three pixels continuous in the scanning direction, the dots corresponding to each pixel in the image region are the main dots (M1 to M3) and the sub dots. (S1 to S3) are recorded at separate positions. On the other hand, as shown in FIG. 22B, with respect to an image area in which four pixels are continuous in the scanning direction, the dot corresponding to the most downstream pixel in the scanning forward direction (arrow XA direction) of the recording head 26 in the image area. During recording, the recording head 26 scans and moves at the second speed. For this reason, as shown in FIG. 22B, for an image region that is continuous in four pixels in the scanning direction, the main pixel corresponding to the most downstream pixel in the scanning forward direction (arrow XA direction) of the recording head 26 in the image region. For the dot M4, the sub dot S4 corresponding to the main dot M4 is recorded so as to overlap the main dot M4.

  Therefore, the recording apparatus 10 </ b> C of the present embodiment can realize high-speed image formation while suppressing image quality deterioration due to sub-droplets.

(Fifth embodiment)
In the first embodiment, when recording dots corresponding to each of discontinuous pixels in the scanning direction of the carriage 24 (recording head 26), the recording head 26 is decelerated to the second speed, and between the dots, A case has been described in which acceleration is performed from the second speed toward the first speed and deceleration is performed from the first speed to the second speed.

  In the present embodiment, for the discontinuous pixels in the scanning direction of the carriage 24, when the interval between the discontinuous pixels is equal to or less than a predetermined interval, the scanning direction of the carriage 24 in the discontinuous pixel group. The recording head 26 scans and moves at a second speed when recording dots corresponding to the most upstream pixel, and the first speed when recording dots corresponding to pixels downstream of the pixels in the scanning direction of the carriage 24. Thus, the recording head 26 is scanned and moved.

  Then, for the discontinuous pixels in the scanning direction of the carriage 24, when the interval between the discontinuous pixels exceeds a predetermined interval, the second dot is recorded at the time of recording the dot corresponding to each of the discontinuous pixels. The recording head 26 is scanned and moved at a speed.

  FIG. 23 is a functional block diagram in which the recording apparatus 10D according to the present embodiment is divided for each function realizing unit determined based on hardware and software. As shown in FIG. 23, the recording apparatus 10D of the present embodiment includes an operation unit 49, an interface 61, a detection unit 48, a control unit 51D, a carriage motor driver 58, a carriage drive unit 60, a conveyance motor driver 64, and a conveyance drive unit. 62 and the recording head 26. The control unit 51D includes an image data receiving unit 51, an image data reading unit 52, an image region extracting unit 53, a boundary specifying unit 54D, a scanning speed determining unit 55D, a storage unit 56, and a print control unit 57. The recording apparatus 10D according to the present embodiment includes a control unit 51D including a boundary specifying unit 54D and a scanning speed determining unit 55D instead of the control unit 50 including the boundary specifying unit 54 and the scanning speed determining unit 55. Other than this, the configuration is the same as that of the recording apparatus 10 of the first embodiment. For this reason, only different parts will be described in detail.

  In the present embodiment, in addition to the first speed and the second speed, the storage unit 56 further stores information indicating the pixel interval of the speed adjustment target in discontinuous pixels in the scanning direction. The information indicating the pixel interval of the speed adjustment target includes pixels that are discontinuous in the scanning direction (for example, n dot intervals (n is an integer of 1 or more)) included in the image data. In this case, the interval between the target pixels for which the scanning speed of the carriage 24 (recording head 26) is set to the second speed is shown. Examples of the information indicating the pixel interval of the speed adjustment target include information indicating a 3-dot interval and a 5-dot interval.

  Information indicating the pixel interval of the speed adjustment target may be stored in the storage unit 56 in advance, or may be input to the operation unit 49 by the user according to an operation instruction and stored in the storage unit 56.

  The boundary specifying unit 54D specifies, as a boundary pixel, a pixel located in the most downstream in the scanning direction (arrow X direction) of the recording head 26 in each of the YMCK image regions extracted by the image region extracting unit 53. When the image area is composed of one pixel (discontinuous pixels in the scanning direction), the boundary specifying unit 54D has the discontinuous pixels arranged in the scanning direction at intervals in the scanning direction. It is determined whether or not. When the discontinuous pixels are not arranged at intervals in the scanning direction, the boundary specifying unit 54D performs the same processing as the boundary specifying unit 54 in the first embodiment.

  On the other hand, when the discontinuous pixels are arranged at intervals in the scanning direction, the boundary specifying unit 54D determines that the interval between the plurality of discontinuous pixels in the scanning direction is the pixel interval for speed adjustment. When it is more than the information shown, each of the pixels is specified as a boundary pixel. In addition, when the discontinuous pixels are arranged at intervals in the scanning direction, the boundary specifying unit 54D determines that the interval between the plurality of discontinuous pixels in the scanning direction is the pixel interval for speed adjustment. When the information is less than the indicated information, the pixel located at the most upstream in the scanning direction of the recording head 26 among the plurality of pixels arranged in the discontinuous and scanning direction is specified as the boundary pixel. Then, among the plurality of pixels, the pixels on the downstream side in the scanning direction of the recording head 26 from the pixels specified as the boundary pixels are not specified as the boundary pixels.

  Then, the scanning speed determination unit 55D, based on the first speed and the second speed stored in the storage unit 56, the image data received from the boundary specifying unit 54D, and information indicating the boundary pixel, Similarly to the scanning speed determination unit 55 of the first embodiment, the scanning speed information is generated. That is, the scanning speed determination unit 55D determines the scanning speed of the recording head 26 when recording the dots corresponding to the boundary pixels to the second speed that is lower than the first speed, and in the scanning direction (arrow X direction). The scanning speed of the recording head 26 corresponding to each position in the scan movable range AB of the recording head 26 is determined, and scanning speed information is generated.

  Here, in the information indicating the boundary pixel received from the boundary specifying unit 54D, when discontinuous pixels in the scanning direction as the image region are arranged at intervals, a plurality of discontinuous pixels in the scanning direction are arranged. When the pixel interval is less than the information indicating the pixel interval of the speed adjustment target, out of the plurality of pixels arranged discontinuously and arranged in the scanning direction, the pixel located at the uppermost stream in the scanning direction of the recording head 26, This is specified as a boundary pixel. In the information indicating the boundary pixel received from the boundary specifying unit 54D, when discontinuous pixels in the scanning direction as the image region are arranged at intervals, a plurality of pixels discontinuous in the scanning direction Is equal to or greater than information indicating the pixel interval of the speed adjustment target, each of the pixels is specified as a boundary pixel.

  For this reason, the scanning speed information generated by the scanning speed determination unit 55D indicates that when a plurality of discontinuous pixels are arranged in the scanning direction, the interval between the plurality of discontinuous pixels in the scanning direction is a pixel whose speed is to be adjusted. When the information is greater than or equal to the information indicating the interval, the information is generated so that the scanning speed of the recording head 26 at the time of recording the dot corresponding to each pixel becomes the second speed. Further, the scanning speed information generated by the scanning speed determination unit 55D indicates that when a plurality of discontinuous pixels are arranged in the scanning direction, the interval between the plurality of discontinuous pixels in the scanning direction is the pixel interval for speed adjustment. The scanning speed of the recording head 26 at the time of recording dots corresponding to the pixel located in the uppermost stream in the scanning direction of the recording head 26 among the plurality of pixels is the second speed. To be generated.

  24 and 25 show an example of the scanning speed information determined by the inspection speed determination unit 55D. 24 and 25 show the position coordinates in the scanning direction (arrow X direction) of the carriage 24, that is, the recording head 26 when ejecting ink droplets while moving the recording head 26 in the scanning forward direction (arrow XA direction). An example of the relationship between the scanning speed of the carriage 24 (recording head 26) is shown.

  For example, as shown in FIG. 24, the recording head 26 scans and moves in the scanning forward direction (arrow XA direction), and records dots corresponding to a plurality of discontinuous pixels at intervals of one dot in the scanning direction. As information indicating the pixel interval of the speed adjustment target, for example, information indicating 5 dots is stored in the storage unit 56.

  In this case, for example, as shown in FIG. 24, the scanning speed determination unit 55D creates scanning speed information indicating the following fluctuations in scanning speed. For example, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, the second velocity V1 is set when the dot corresponding to the pixel located in the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26 is recorded. Thus, the speed of the recording head 26 (carriage 24) is determined. Next, acceleration is performed at a predetermined acceleration rate from the second speed V1 toward the first speed V2 toward the downstream side in the scanning forward direction, and the first speed V2 is maintained. That is, the scanning speed determination unit 55D creates, for example, scanning speed information indicated by a line 79 in FIG.

  For this reason, in the present embodiment, as shown in FIG. 24, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, it is positioned at the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26. For the dot corresponding to the pixel, the sub dot S1 corresponding to the main dot M1 is recorded on the main dot M1. The main dots M2 to M4 recorded at intervals of 3 dots or less downstream from the dot M1 in the scanning forward direction (arrow XA direction) are recorded by the recording head 26 that scans and moves at the first speed V2. Is done. Therefore, for these main dots M2 to M4, the corresponding sub dots S2 to S4 are recorded at positions where they do not overlap with the main dots M2 to M4.

  Further, as shown in FIG. 25, the recording head 26 scans in the scanning forward direction (arrow XA direction), and records dots corresponding to a plurality of discontinuous pixels at intervals of 5 dots in the scanning direction. As information indicating the pixel interval of the speed adjustment target, for example, information indicating 5 dots is stored in the storage unit 56.

  In this case, for example, as shown in FIG. 25, the scanning speed determination unit 55D creates scanning speed information indicating the following fluctuations in scanning speed. For example, the speed of the recording head 26 (carriage 24) is determined so that the second speed V1 is obtained when each dot corresponding to a plurality of pixels discontinuous in the scanning direction is recorded. Then, between these dots, after accelerating at a predetermined acceleration rate from the second speed V1 toward the first speed V2 toward the downstream side in the scanning forward direction, the first speed V2 to the first speed. The vehicle decelerates at a predetermined deceleration rate toward a speed V1 of 2. That is, the scanning speed determination unit 55D creates, for example, scanning speed information indicated by a line 80 in FIG.

  For this reason, in the present embodiment, as shown in FIG. 25, among the dots corresponding to a plurality of pixels discontinuous in the scanning direction, it is positioned at the uppermost stream in the scanning forward direction (arrow XA direction) of the recording head 26. For the dot corresponding to the pixel, the sub dot S1 corresponding to the main dot M1 is recorded on the main dot M1. Further, even with respect to the main dot M2, which is recorded at an interval of 5 dots or more downstream from the main dot M1 in the scanning forward direction (arrow XA direction), the dots are formed by the recording head 26 that scans and moves at the second speed V1. To be recorded. For this reason, also for the main dot M2, the corresponding sub dot S2 is recorded at a position overlapping the main dot M2.

  Therefore, in the recording apparatus 10D of the present embodiment, it is possible to realize high-speed image formation while suppressing image quality deterioration due to sub-droplets.

  In each of the above-described embodiments, various programs executed by each of the control units 50, 50A, 50B, 50C, and 50D are stored on a computer connected to a network such as the Internet and downloaded via the network. You may comprise so that it may provide. The various programs are recorded in a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, and a DVD (DigitAl Verstile Disk) in a file that can be installed or executed. May be provided as a computer program product.

10, 10A, 10B, 10C, 10D Recording device 26 Recording head 53, 53B, 53C Image area extraction unit 54, 54B, 54C, 54D Boundary specifying unit 55, 55A, 55B, 55C, 55D Scanning speed determination unit 57 Print control unit 60 Carriage drive

JP 2006-27181 A

Claims (10)

A recording head for recording dots corresponding to each pixel by ejecting ink droplets from each of the nozzles;
Drive means for scanning and moving the recording head in the scanning direction at a first speed relative to the recording medium;
Extraction means for extracting, as an image area, each of a pixel group that is continuous in the scanning direction and a discontinuous pixel in the scanning direction among pixels that record the dots in the image data;
Specifying means for specifying, as a boundary pixel, a pixel located at the most downstream side in the scanning direction in each of the image regions;
The scanning speed of the recording head at the time of recording the dots corresponding to the boundary pixels is determined as a second speed that is lower than the first speed, and the scanning speed at each position in the scanning direction of the recording head is determined. A decision means to
Control means for controlling the driving means in accordance with the determined scanning speed;
An image forming apparatus.   The second speed is determined by the main dots recorded by the main droplets of the first ink amount among the droplets ejected from the nozzles of the recording head and the sub-drops recorded by the sub-drops separated from the main droplets. The image forming apparatus according to claim 1, wherein the dot is a speed at which the dot is recorded as the dot.   The image forming apparatus according to claim 1, wherein the second speed is a speed at which the scanning movement of the recording head is stopped. Said determining means, as the scanning speed of the recording head during recording of dots corresponding to the boundary pixels, determines the ink large amount of boundary pixels as fast run査速degree of discharge when recording dots, claim The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the image data includes a pixel that records a dot at an end in the scanning direction.   The extraction means includes a pixel group that is continuous in the scanning direction among pixels that record dots in the image data having a color light absorption rate equal to or greater than a predetermined value, and a discontinuity in the scanning direction. The image forming apparatus according to claim 1, wherein each of the pixels is extracted as an image area.   The extraction unit extracts the pixel group as the image area when the pixel group continuous in the scanning direction is a continuous pixel group of a predetermined number of pixels or more. The image forming apparatus according to any one of 6.   The specifying unit is configured so that, when there are a plurality of discontinuous pixels in the scanning direction as the image area at intervals in the scanning direction, the plurality of discontinuous pixels in the scanning direction are included in the scanning direction. The image forming apparatus according to claim 1, wherein pixels located at predetermined intervals are specified as boundary pixels. The determination unit corresponds to pixels that are arranged in the scanning direction at intervals equal to or smaller than a predetermined interval in the scanning direction among the discontinuous pixels in the scanning direction as the boundary pixels. the scanning speed of the recording head during recording of dots, and the scanning speed of the recording head between the dots, Ru determined Teisu the second speed, the image forming apparatus according to claim 1. A recording head that records dots corresponding to each pixel by ejecting ink droplets from each of the nozzles, and a driving unit that scans and moves the recording head in the scanning direction at a first speed relative to the recording medium. An image forming method executed by an image forming apparatus comprising:
Extracting each pixel group that is continuous in the scanning direction and pixels that are discontinuous in the scanning direction among the pixels that record the dots in the image data, as an image region;
Identifying a pixel located at the most downstream in the scanning direction in each of the image regions as a boundary pixel;
The scanning speed of the recording head at the time of recording the dots corresponding to the boundary pixels is determined as a second speed that is lower than the first speed, and the scanning speed at each position in the scanning direction of the recording head is determined. And steps to
Controlling the driving means according to the determined scanning speed;
An image forming method.

Images