JP4483982B2 - Printing to the end of the printing paper without soiling the platen - Google Patents

Description

  The present invention relates to a technique for recording dots on the surface of a print medium using a dot recording head, and more particularly to a technique for printing up to the end of printing paper without soiling the platen.

  In recent years, printers that eject ink from nozzles of a print head have become widespread as computer output devices. FIG. 24 is a side view showing the periphery of the print head of a conventional printer. The printing paper P is supported on the platen 26o so as to face the head 28o. The printing paper P is fed in the direction of arrow A by the upstream paper feed rollers 25p and 25q arranged upstream of the platen 26o and the downstream paper feed rollers 25r and 25s arranged downstream of the platen 26o. . When ink is ejected from the head, dots are sequentially recorded on the printing paper P, and an image is printed.

In the above printer, if an image is to be printed to the edge of the printing paper without margins, the image data is set to the edge of the printing paper, and when printing, the printing paper is placed at the edge below the printing head, that is, the platen. It is necessary to dispose the ink droplets from the print head so as to be positioned above. However, in such printing, a margin may be formed at the end of the printing paper due to an error in feeding the printing paper or a deviation in the landing position of the ink droplets. In addition, due to an error in feeding the printing paper or a deviation in the landing position of the ink droplet, the ink droplet may come off from the end of the printing paper to be originally landed and land on the platen. In such a case, the printing paper that subsequently passes over the platen is soiled by the ink that has landed on the platen. In particular, the error in feeding the printing paper tends to vary depending on the slipperiness of the printing paper used. For this reason, an error in feeding the printing paper is difficult to predict at the time of designing the printer, as compared with a deviation in the landing position of the ink droplets. In addition, various unpredictable situations may occur while the printing paper is being fed. For this reason, compared with the downstream end portion (leading end portion) in the conveyance direction of the printing paper sent at the start of conveyance of the printing paper, the feeding at the upstream end portion (tail end portion) in the conveyance direction of the printing paper sent just before the end of conveyance. The position of can vary significantly.

JP 2000-1108058

  The present invention has been made in order to solve the above-described problems in the prior art, and an object of the present invention is to provide a technique for performing printing up to the end of the printing paper without landing ink droplets on the platen.

  In order to solve at least a part of the above-described problems, the present invention provides a dot recording apparatus that records dots on the surface of a print medium using a dot recording head provided with a plurality of dot forming elements that eject ink droplets. A predetermined process is performed as a target. The dot recording apparatus includes a main scanning driving unit that performs at least one of a dot recording head and a printing medium to perform main scanning, and drives at least some of a plurality of dot forming elements during the main scanning. A head drive unit that forms dots, a platen that extends in the main scanning direction so as to face the dot forming element in at least a part of the path of the dot recording head along the main scanning direction, and main scanning A sub-scanning drive unit that performs sub-scanning by driving the print medium in a direction crossing the main scanning direction, and a control unit for controlling each unit.

  Further, the platen of the dot recording device is provided to extend in the main scanning direction so as to face the dot forming element in at least a part of the path of the dot recording head along the main scanning direction. A first groove portion provided at a position facing at least some of the dot forming elements is included.

  When dots are formed by such a dot recording apparatus, first, a predetermined print mode is selected from a plurality of print modes. Then, print data for recording an image in an extended area having a length exceeding the upper end and the lower end of the print medium is prepared according to the selected print mode. Thereafter, when printing the upper end portion and the lower end portion of the print medium based on the print data, ink droplets are ejected from at least a part of the dot forming elements facing the first groove portion. According to such an aspect, dots are formed by preparing an extended area suitable for each print mode so that printing can be performed appropriately without providing a margin at the edge of the print medium. be able to. Further, since the dot forming element facing the first groove portion is used in printing the end portion, the platen is not soiled when the end portion of the print medium is printed without a blank space.

  In addition, when a plurality of print modes include print modes in which the recording density of rasters in the sub-scanning direction is different from each other, the number of rasters constituting the extended area is selected when the print data is prepared. It is preferable to determine according to the mode. In this way, the size of the extended region in the sub-scanning direction can be defined according to the print mode using the concept of “raster” that is actually used by the printing apparatus when printing.

  In addition, when printing the upper end part and lower end part of a printing medium, it is preferable to print using only the dot formation element facing a 1st groove part. With such an aspect, when printing the upper end portion and the lower end portion of the print medium, the platen is not soiled even when the positions of the upper end and the lower end are shifted from the top of the first groove portion.

  The extended area is set in order from the top, exceeding the upper end of the print medium, and the outer upper end portion assigned to the dot formation element in which the dot formation of the portion faces the first groove portion, and the upper end portion of the print medium Correspondingly, the inner upper end assigned to the dot forming element facing the first groove, and the intermediate part corresponding to the intermediate part of the print medium, and the lower end part of the print medium The dot formation is set beyond the lower end of the print medium and assigned to the dot forming element facing the first groove, and the dot formation of the part is assigned to the dot forming element facing the first groove. When the print data is prepared, it is preferable that the following is performed when the print data is prepared.

  That is, in the printing mode in which the recording density of the rasters in the sub-scanning direction is different from each other and printing is performed with no margin at the upper end and the lower end of the printing medium, It is preferable to adjust the number of rasters at the outer upper end so that the dimensions in the scanning direction are equal to each other. In the printing mode in which the raster recording densities in the sub-scanning direction are different from each other, and printing is performed with no margins on the upper end and the lower end of the printing medium, It is preferable to adjust the number of rasters at the outer lower end so that the dimensions in the scanning direction are equal to each other.

  In this way, the dimensions of the outer upper end and the outer lower end can be made substantially equal between different printing modes. For this reason, even in different print modes, it is possible to define the extension region so that the margins are hardly formed at the end of the print medium.

  In the printing mode in which the raster recording densities in the sub-scanning direction are different from each other, and printing is performed with no margins at the upper end and the lower end of the printing medium, the same type of printing medium is It is preferable to adjust the number of rasters at the inner upper end so that the dimensions in the scanning direction are equal to each other. In the printing mode in which the recording density of the rasters in the sub-scanning direction is different from each other and printing is performed with no margins at the upper end and the lower end of the printing medium, the same type of printing medium is It is preferable to adjust the number of rasters at the inner and lower ends so that the dimensions in the scanning direction are equal to each other.

  In this way, the dimensions of the inner upper end and the inner lower end can be made substantially equal between different printing modes. For this reason, even in different printing modes, it is possible to determine the extension region so that the platen is hardly stained to the same extent.

  When ejecting ink droplets to the upper end of the print medium, the print medium is supported by the platen, the upper end of the print medium is over the opening of the first groove, and the upper end of the print medium is sub-scanned. It is preferable to set the position of the print medium in the sub-scanning direction so that it is positioned upstream of the dot forming element at the downstream end in the sub-scanning direction. When ejecting ink droplets to the lower end of the print medium, the print medium is supported by the platen, the lower end of the print medium is over the opening of the first groove, and the lower end of the print medium is sub-scanned. It is preferable to set the position of the print medium in the sub-scanning direction so that it is positioned downstream of the dot forming element at the upstream end in the sub-scanning direction. In this way, it is possible to print without margins up to the upper and lower ends of the print medium without landing ink droplets on the platen.

  Further, when a plurality of printing modes include printing modes in which the recording densities of pixels in the main scanning direction are different from each other, the following is preferable. That is, a pair of second plates provided on the platen in a range including at least a landing range of ink droplets from a plurality of dot forming elements in the sub-scanning direction, and provided at an interval substantially equal to the width of the print medium. The groove is provided. Then, when determining the number of rasters constituting the expanded area, the width exceeds the left and right ends of the print medium, and the width does not exceed the distance between the side walls outside the pair of second grooves. In this way, the expansion area is set, and the number of pixels in the main scanning direction of each raster constituting the expansion area is substantially determined according to the selected print mode. In this way, it is possible to prepare print data that can be printed without margins to the left and right ends of the print medium without causing ink droplets to land on the platen.

  Note that it is preferable to set the position of the print medium in the main scanning direction so that the print medium is supported by the platen and both ends of the print medium are respectively located on the openings of the second grooves. In the main scanning, when the dot forming element is at a position facing the print medium, and when the dot forming element is at a position beyond the side edge of the print medium and at the position facing the second groove. The ink droplets are preferably ejected according to the print data. In this way, it is possible to print without margins to the left and right edges of the print medium without landing ink droplets on the platen.

  The present invention also provides dot recording control for generating print data to be supplied to a dot recording unit that records dots on the surface of a print medium using a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets. It can also be realized as an aspect of the apparatus. Here, the dot recording unit drives at least one of the dot recording head and the print medium to perform main scanning, and drives at least a part of a plurality of dot forming elements to form dots, thereby performing main scanning. In this interval, the print medium is driven in a direction crossing the main scanning direction to perform sub-scanning. Further, at least a part of the plurality of dot forming elements is formed by extending in the main scanning direction so as to face the dot forming element in at least a part of the path of the dot recording head along the main scanning direction. A platen having a first groove provided at a position facing the element is provided.

  The print control apparatus includes an image data generation unit, a user interface unit, an extended area storage unit, and a print data generation unit. The image data generation unit generates image data that is image data to be recorded on the print medium. The user interface unit displays on the display unit a selection screen that allows the user to select one of a plurality of printing modes registered in advance, and receives a selection by the user. The extended area storage unit stores the number of rasters constituting the extended area having a length exceeding the upper end and the lower end of the print medium for each print mode. The print data generation unit generates print data for recording dots forming an image over the extended area from the selected print mode, the number of rasters constituting the extended area, and the image data. With such an aspect, it is possible to prepare an extended area suitable for each printing mode and perform printing appropriately without providing a margin at the end of the printing medium.

Note that the present invention can be realized in various modes as described below.
(1) A dot recording method, a dot recording control method, a printing control method, and a printing method.
(2) A dot recording device, a dot recording control device, a printing control device, and a printing device.
(3) A computer program for realizing the above apparatus and method.
(4) A recording medium on which a computer program for realizing the above apparatus and method is recorded.
(5) A data signal embodied in a carrier wave including a computer program for realizing the above-described apparatus and method.

Hereinafter, embodiments of the present invention will be described in the following order based on examples.
A. Summary of embodiment:
B. First embodiment:
B1. Device configuration:
B2. Image recording area:
B3. Printing process steps:
B4. Dot formation:
C. Variations:
C1. Modification 1:
C2. Modification 2:
C3. Modification 3:
C4. Modification 4:
C5. Modification 5:
C6. Modification 6:
C7. Modification 7:

A. Summary of embodiment:
FIG. 1 is an explanatory diagram showing a relationship between a printing paper and an image forming area in the embodiment of the present invention. 1A and 1B, the upper left portion of the printing paper P is shown. The hatched portion is the printing paper P, and the dashed grid portion is the image recording area R. Each broken line represents a pixel. FIG. 1B shows the relationship between the printing paper P and the region R where the image is formed when the recording density of the image is twice that of FIG. In the present invention, the region R in which the printer forms an image by ejecting ink droplets based on the image data is set beyond the edge of the printing paper P. In addition, the code | symbol showing each element is represented by attaching | subjecting "1" and "2" by Fig.1 (a) and FIG.1 (b). However, in the specification, when the elements are collectively referred to including the case of FIG. 1A and the case of FIG. 1B, the reference numerals “1” and “2” are omitted.

  Of the recording area, an area set beyond the upper end Pf of the printing paper P is referred to as an outer upper end portion Rfp. Each pixel of the outer upper end portion Rfp is recorded by only the nozzles of the print head nozzles located at positions facing the downstream groove portion of the platen. Further, in the recording area R, a predetermined area on the downstream side in the sub-scanning direction of the outer upper end Rfp is referred to as an inner upper end Rfq. This inner upper end portion Rfq is also recorded only by the nozzle located at the position facing the downstream groove portion. When recording dots on the printing paper P, even if the printing paper P deviates from the assumed position, as long as the upper edge of the printing paper P is within the outer upper edge Rfp or the inner upper edge Rfq, the edge of the printing paper In addition, there is no margin, and no ink droplets land on the platen.

  The outer upper end portion Rfp and the inner upper end portion Rfq have substantially the same size in the sub-scanning direction even if the image recording density and the recording method are different as long as the size and material of the printing paper on which the image is formed are the same. Is set as follows. That is, the dimension of the outer upper end Rfp1 in the sub-scanning direction is substantially the same as the dimension of the outer upper end Rfp2 in the sub-scanning direction, and the dimension of the inner upper end Rfr1 in the sub-scanning direction and the dimension of the inner upper end Rfr2 in the sub-scanning direction. Are almost the same. By doing so, it is possible to define the expansion region so that the margins are hardly formed at the edge of the print medium to the same extent even in different print modes. That is, the range of deviation of the printing paper P where no margin is formed at the edge of the printing paper and ink droplets do not land on the platen can be kept constant even if the recording density and recording method of the image are different.

B. First embodiment:
B1. Device configuration:
FIG. 2 is a block diagram illustrating a software configuration of the printing apparatus. In the computer 90, an application program 95 operates under a predetermined operating system. A video driver 91 and a printer driver 96 are incorporated in the operating system, and image data D to be transferred to the printer 22 is output from the application program 95 via these drivers. An application program 95 that performs image retouching and the like reads an image from the scanner 12, performs predetermined processing on the image, and displays the image on the CRT 21 via the video driver 91. Data ORG supplied from the scanner 12 is original color image data ORG that is read from a color original and includes three color components of red (R), green (G), and blue (B).

  When the application program 95 issues a print command, the printer driver 96 of the computer 90 receives image data from the application program 95, and this is a signal that can be processed by the printer 22 (here, cyan, magenta, light cyan, light magenta, Multi-valued signals for yellow and black). In the example shown in FIG. 2, the printer driver 96 includes a resolution conversion module 97, a color correction module 98, a halftone module 99, and a rasterizer 100. Further, an extended area table EAT, a color correction table LUT, and a dot formation pattern table DT are also stored. The application program 95 corresponds to an “image data generation unit” in the claims. The printer driver 96 corresponds to a “print data generation unit”. More specifically, the resolution conversion module 97, the color correction module 98, the halftone module 99, and the rasterizer 100 correspond to a “print data generation unit”.

  The resolution conversion module 97 serves to convert the resolution of the color image data handled by the application program 95, that is, the number of pixels per unit length into a resolution that can be handled by the printer driver 96. The resolution conversion module 97 refers to the extended area table EAT when converting the resolution of the image data. Then, the image data is converted into data that can record an image recording area determined from the preselected paper type and the extended area table EAT at a specified resolution. The image recording area and the extended area table EAT will be described later in detail.

  Since the image data thus converted in resolution is still image information composed of three colors of RGB, the color correction module 98 refers to the color correction table LUT, and cyan (C), which is used by the printer 22 for each pixel. The data is converted into data of each color of magenta (M), light cyan (LC), light magenta (LM), yellow (Y), and black (K).

  The color-corrected data has gradation values with a width of, for example, 256 gradations. The halftone module 99 executes halftone processing for expressing the gradation value in the printer 22 by forming dots in a dispersed manner. The halftone module 99 refers to the dot formation pattern table DT, sets the dot formation pattern of each ink dot in accordance with the tone value of the image data, and executes halftone processing. The processed image data is rearranged in the order of data to be transferred to the printer 22 by the rasterizer 100, and output as final print data PD. The print data PD includes raster data indicating the dot recording state during each main scan and data indicating the sub-scan feed amount. The raster data included in the print data PD and the data indicating the sub-scan feed amount correspond to the image data D that substantially represents the image to be printed. That is, these data have dot recording state information for each pixel in the extended area as image data. In this embodiment, the printer 22 only serves to form ink dots in accordance with the print data PD and does not perform image processing, but of course, these processes may be performed by the printer 22.

  Next, a schematic configuration of the printer 22 will be described with reference to FIG. As shown in the figure, the printer 22 includes a mechanism for transporting the paper P by a paper feed motor 23, guides 29a and 29b (not shown in FIG. 3) for guiding the print paper P during transport, and a carriage motor 24. Mechanism for reciprocating the carriage 31 in the axial direction of the platen 26, a mechanism for driving the print head 28 mounted on the carriage 31 to eject ink and forming ink dots, the paper feed motor 23, the carriage The motor 24, the print head 28, and a control circuit 40 that controls the exchange of signals with the operation panel 32 are included. The printer 22 corresponds to “dot recording unit” and “dot recording device” in the claims.

  A mechanism for reciprocating the carriage 31 in the axial direction of the platen 26 is installed in a direction perpendicular to the conveyance direction of the printing paper P, and between the carriage motor 24 and the slide shaft 34 that slidably holds the carriage 31. A pulley 38 that stretches an endless drive belt 36, a position detection sensor 39 that detects the origin position of the carriage 31, and the like.

  The carriage 31 is a color ink containing a black ink (K) cartridge 71 and six inks of cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). Cartridge 72 can be mounted. A total of six ink ejection heads 61 to 66 are formed on the print head 28 below the carriage 31, and introduction pipes 67 that guide ink from the ink tanks to the heads for the respective colors are formed at the bottom of the carriage 31. It is erected. When the black (K) ink cartridge 71 and the color ink cartridge 72 are mounted on the carriage 31 from above, the introduction pipe 67 is inserted into the connection hole provided in each cartridge, and the ejection heads 61 to 66 are ejected from each ink cartridge. Ink can be supplied to the printer.

  FIG. 4 is an explanatory diagram showing the arrangement of the inkjet nozzles Nz in the ink ejection heads 61-66. These nozzles are arranged from six sets of nozzle arrays that eject ink for each color of black (K), cyan (C), light cyan (LC), magenta (M), light magenta (LM), and yellow (Y). Each of the 48 nozzles is arranged in a line at a constant nozzle pitch k. As described above, the six nozzle arrays are arranged so as to be aligned along the main scanning direction. More specifically, corresponding nozzles of each nozzle array are arranged on the same main scanning line. The “nozzle pitch” is a value indicating how many rasters (that is, how many pixels) the intervals in the sub-scanning direction of the nozzles arranged on the print head are. For example, the pitch k of the nozzles arranged with an interval of 3 rasters therebetween is 4.

  FIG. 5 is a plan view showing the periphery of the platen 26. The platen 26 is provided in the main scanning direction longer than the maximum width of the printing paper P that can be used in the printer. In addition, upstream paper feed rollers 25 a and 25 b are provided upstream of the platen 26. The upstream paper feed roller 25a is a single drive roller, whereas the upstream paper feed roller 25b is a plurality of small rollers that rotate freely. Further, downstream paper feed rollers 25c and 25d are provided downstream of the platen. The downstream paper feed roller 25c is a plurality of rollers provided on the drive shaft, and the downstream paper feed roller 25d is a plurality of small rollers that freely rotate. A groove is provided on the outer peripheral surface of the downstream paper feed roller 25d in parallel with the rotation axis direction. That is, the downstream paper feed roller 25d has teeth (a portion between the grooves) radially on the outer peripheral surface, and looks like a gear when viewed from the rotation axis direction. The downstream side paper feed roller 25 d is commonly called “gloss roller” and plays a role of pressing the printing paper P onto the platen 26. The downstream paper feed roller 25c and the upstream paper feed roller 25a rotate in synchronization so that the outer peripheral speeds are equal.

  The print head 28 reciprocates in the main scanning on the platen 26 sandwiched between the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d. The printing paper P is held by the upstream paper feeding rollers 25 a and 25 b and the downstream paper feeding rollers 25 c and 25 d, and a portion therebetween is supported by the upper surface of the platen 26 so as to face the nozzle row of the printing head 28. Sub-scan feed is performed by the upstream paper feed rollers 25 a and 25 b and the downstream paper feed rollers 25 c and 25 d, and images are sequentially recorded by ink ejected from the nozzles of the print head 28.

  The platen 26 is provided with an upstream groove 26f and a downstream groove 26r on the upstream and downstream sides in the sub-scanning direction, respectively. The upstream groove portion 26f and the downstream groove portion 26r are provided longer than the maximum width of the printing paper P that can be used in the printer along the main scanning direction. Absorbing members 27f and 27r for receiving and absorbing the ink droplet Ip are disposed at the bottoms of the upstream groove portion 26f and the downstream groove portion 26r, respectively. The downstream groove portion 26r is provided at a position facing a part of the nozzle group Nr on the downstream side including the most downstream nozzle among the nozzles Nz on the print head 28 (the nozzles indicated by hatching in FIG. 5). Yes. The upstream groove 26f is provided at a position facing a part of the upstream nozzle group Nf (not shown in FIG. 5) including the most upstream nozzle among the nozzles on the print head 28. The upstream groove portion 26f and the downstream groove portion 26r correspond to the “first groove portion” in the claims.

  Further, the platen 26 is provided with a left groove portion 26a and a right groove portion 26b that extend in the sub-scanning direction so as to connect both ends of the upstream groove portion 26f and the downstream groove portion 26r. The left groove portion 26a and the right groove portion 26b are provided in a range in the sub-scanning direction longer than the landing range of the ink droplets from the nozzle row on the print head. The left groove 26a and the right groove 26b have a maximum width in the main scanning direction among the printing papers P that can be recorded by the printer 22 (in the main scanning direction). It is provided so as to be equal to the width. The left groove 26a and the right groove 26b are arranged in the main scanning direction of the printing paper P when the maximum width printing paper P usable by the printer 22 is at a predetermined main scanning position guided by the guides 29a and 29b. It is only necessary that one side end Pa is positioned on the left groove 26a and the other side end Pb is positioned on the right groove 26b. Therefore, as described above, when the printing paper P is in a fixed position, the side edges of the printing paper P are located on the left groove 26a, in addition to the aspect in which the side edges are on the center line of the left groove 26a and the right groove 26b. You may provide so that it may be located inside and the outer side rather than the centerline of the right side groove part 26b. The left groove portion 26a and the right groove portion 26b correspond to a “second groove portion” in the claims. The upstream groove portion 26f, the downstream groove portion 26r, the left groove portion 26a, and the right groove portion 26b are connected to each other to form a quadrilateral groove portion.

  Further, the platen 26 is provided with right groove portions 26b2 and 26b3 extending in the sub-scanning direction so as to connect the intermediate portions of the upstream groove portion 26f and the downstream groove portion 26r. The right groove 26b2 is smaller than the left groove 26a in that the interval between the center lines is smaller than the maximum width in the main scanning direction of the print paper P that can be recorded by the printer 22. It is provided so as to be equal to the width of the printing paper P. The same applies to the right groove 26b3. If the printer 22 is capable of printing up to the A3 size in the vertical arrangement, the distance between the center lines of the left groove portion 26a and the right groove portion 26b is the length of the short side of the A3 size. At this time, for example, the distance between the center lines of the left groove part 26a and the right groove part 26b2 can be the length of the short side of B4 size, and the distance between the center lines of the left groove part 26a and the right groove part 26b3 is short of the A4 size. It can be the length of the side. In addition to these, a right groove corresponding to the A5 size, a right groove corresponding to a postcard size, and the like can be provided. The set of the left groove portion 26a and the right groove portion 26b, the set of the left groove portion 26a and the right groove portion 26b2, and the set of the left groove portion 26a and the right groove portion 26b correspond to “a pair of second groove portions” in the claims. .

  An absorbing member 27 for receiving and absorbing the ink droplet Ip is disposed at the bottom of each of these grooves. Hereinafter, the code | symbol of the absorption member 27 of each groove part may be described as 27f, 27r, 27a, 27b, 27b2, and 27b3 corresponding to the code | symbol of each groove part.

  When the sub-scan feed is performed by the upstream paper feed rollers 25a and 25b and the downstream paper feed rollers 25c and 25d, the printing paper P passes over the openings of the upstream groove 26f and the downstream groove 26r. . Further, on the platen 26, the left end Pa is positioned on the left groove 26a, and the right end Pb is positioned on the right grooves 26b, 26b2, and 26b3 according to the width of each print sheet. As described above, the guides 29a and 29b are positioned in the main scanning direction.

  Next, the internal configuration of the control circuit 40 (see FIG. 3) of the printer 22 will be described. Inside the control circuit 40, in addition to the CPU 41, PROM 42, and RAM 43, a PC interface 45 that exchanges data with the computer 90, and a drive that outputs ink dot ON / OFF signals to the ink ejection heads 61 to 66. A buffer 44 is provided, and these elements and circuits are connected to each other by a bus. The control circuit 40 receives the dot data processed by the computer 90, temporarily stores it in the RAM 43, and outputs it to the driving buffer 44 at a predetermined timing. The RAM 43 corresponds to a “print data storage unit” in the claims.

  The printer 22 having the hardware configuration described above moves the carriage 31 back and forth by the carriage motor 24 while transporting the paper P by the paper feed motor 23 and simultaneously drives the piezo elements of the nozzle units of the print head 28. The ink droplets Ip are ejected to form ink dots to form a multicolor image on the paper P.

  In the printer of this embodiment, the upper end Pf of the printing paper P is printed on the downstream groove 26r, and the lower end Pr is printed on the upstream groove 26f. A printing process different from the intermediate part of the printing paper is performed. In this specification, the printing process in the middle part of the printing paper is called “intermediate processing”, the printing process in the vicinity of the upper edge of the printing paper is “upper edge processing”, and the printing process in the vicinity of the lower edge of the printing paper is “lower edge processing”. Call it. In addition, when the upper end process and the lower end process are collectively referred to as “upper / lower end process”.

B2. Image recording area:
FIG. 6 is an explanatory diagram showing the relationship between the image recording region R and the printing paper P. In this embodiment, the image recording area R is set beyond the upper end Pf of the printing paper P to the outside of the printing paper P. Similarly, for the lower end Pr, the left end Pa, and the right end Pb of the printing paper P, the image recording area R is set beyond the end of the printing paper P to the outside of the printing paper P. Therefore, in the present embodiment, the recording area R of the image at the time of printing and the size of the printing paper P, and the relationship between the assumed position of the recording area R and the arrangement of the printing paper P are as shown in FIG. Hereinafter, an image recording area is referred to as an “extended area R”. Since the left and right names of the left edge Pa and right edge Pb of the printing paper P correspond to the left and right names of the printer 22, the actual left and right edges Pa and the right edge Pb of the printing paper P are named. Is reversed.

  The dimension in the main scanning direction (left and right direction in FIG. 6) of the portion of the expansion region R that is set beyond the left and right side edges Pa and Pb of the printing paper P differs depending on the dimensions of the printing paper P in the main scanning direction. A portion of the extended region R that is set beyond the left end Pa of the printing paper P is called an outer left end portion Rap of the recording region, and a portion that is set beyond the right end Pb is the outer right end of the recording region. This is called a part Rbp. However, the width Wa of the outer left end portion Rap is equal to the width Wb of the outer right end portion Rbp. Wa and Wb may be different values.

  On the other hand, the dimension in the sub-scanning direction (vertical direction in FIG. 6) of the portion of the extended region R set beyond the upper end Pf and the lower end Pr of the printing paper P is the dimension in the sub-scanning direction of the printing paper P. And material (including materials other than paper). A portion of the extended region R that is set to exceed the upper end Pf of the printing paper P is called an outer upper end portion Rfp of the recording region, and a portion that is set to exceed the lower end Pr is the outer lower end portion Rrp of the recording region. Call it.

  The outer upper end portion Rfp is recorded using only the nozzle group Nr (see FIG. 5) in the position facing the downstream groove portion 26r in the nozzle row provided in the print head 28. Here, “only a specific nozzle group is used” means that nozzles other than the specific nozzle group are not used. And about a specific nozzle group, at least one part should just be used. In the extended region R, the portion adjacent to the outer upper end Rfp on the inner side from the upper end Pf of the printing paper P is also recorded by the same nozzle group Nr as the outer upper end Rfp. This portion is called an inner upper end portion Rfq. The outer upper end Rfp and the inner upper end Rfq are collectively referred to as the upper end Rf of the extended region R. On the other hand, the outer lower end Rrp is recorded only by the nozzle group Nf in the nozzle array provided in the print head 28 at a position facing the upstream groove 26f. The portion adjacent to the outer lower end Rrp on the inner side from the lower end Pr of the printing paper P is also recorded by the same nozzle group Nf as the outer lower end Rrp. This portion is called an inner lower end portion Rrq. The outer lower end Rrp and the inner lower end Rrq are collectively referred to as the lower end Rr of the expansion region R.

  FIG. 7 is a table showing examples of dimensions of the outer upper end Rfp, the inner upper end Rfq, the outer lower end Rrp, the inner lower end Rrq, the outer left end Rap, and the outer right end Rbp. Here, the length of the outer upper end Rfp is Lfp, and the length of the inner upper end Rfq is Lfq. The length of the outer lower end Rrp is Lrp, and the length of the inner lower end Rrq is Lrq. These Lfp, Lfq, Lrp, Lrq and Wa, Wb vary depending on the type (size and material) of the printing paper. In FIG. 7, information on the dimensions of the extended regions for the printing paper materials P1, P2, and P3 is shown in the form of a table. The material of the printing paper can be, for example, plain paper, photo print paper, a dedicated gloss film, a dedicated OHP sheet, or the like. These are different in slipperiness in the sub-scanning, and generally, the magnitudes of errors generated in the sub-scanning are different.

  FIG. 8 is an explanatory diagram showing the relationship between different types of printing paper and extended areas. As shown in FIG. 7, when the dimensions of the extended region set beyond the four sides of the printing paper P are determined, the size of the extended region R and the arrangement with respect to the printing paper P are determined. Since the dimensions of the extended region R differ depending on the size and material of the printing paper P, the relationship between the printing paper P and the extended region R is as shown in FIGS. The recording area R is indicated by R1 to R6 in each figure, and the printing paper P is indicated by P1 to P6. Similarly, the upper end Rf and the lower end Rr of the extended region R are also denoted by reference numerals 1 to 6.

  The printing paper P4 in FIG. 8D is larger than the printing paper P1 in FIG. Therefore, the expansion area R4 for recording an image on the printing paper P4 is set larger than the expansion area R1 of the printing paper P1. Further, the printing papers P1, P2, and P3 have the same size but different materials, and the slipperiness of the paper in the sub-scanning is larger in the order of P1, P2, and P3. For this reason, the length in the sub-scanning direction of the extended region R for each print sheet is increased in the order of R1, R2, and R3. More specifically, the length in the sub-scanning direction of the upper end Rf and the lower end Rr recorded by the nozzle on the groove in the extended region R is increased in the order of R1, R2, and R3.

  Here, the size of only one of the outer upper end portion Rfp and the inner upper end portion Rfq of the upper end portion Rf may be changed according to the type of printing paper, but both dimensions may be changed according to the type of printing paper. It is preferable to change it. Similarly, only one of the outer lower end Rrp and the inner lower end Rrq of the lower end Rr may be changed according to the type of printing paper, but both dimensions may be changed according to the type of printing paper. It is preferable to change it.

  FIG. 9 is a table showing an example of the number of rasters and the number of pixels in the extended area portion set beyond the edges of the four sides of the printing paper P. The size of the extension area R and the arrangement with respect to the printing paper P are determined as shown in FIGS. 6 and 7, but the extension area table EAT (see FIG. 2) stores information on the extension area R as the number of rasters and the number of pixels. I remember it.

  For example, in FIG. 7, the length Lfp in the sub-scanning direction of the outer upper end Rfp of the A4 size printing paper made of the material P1 is 3.0 mm. When the raster recording density in the sub-scanning direction and the pixel recording density in the main scanning direction are 720 dpi (dot / inch), the length Lfp in the sub-scanning direction of the outer upper end Rfp is 3.0 mm. As shown in FIG. 9A, the outer upper end portion Rfp needs to be composed of 85 rasters. On the other hand, when the recording density of the raster and the recording density of the pixels in the main scanning direction are 1440 dpi, in order for Lfp to be 3.0 mm, as shown in FIG. The part Rfp needs to be composed of 170 rasters. Here, the number of rasters can be obtained by (length / (1 / recording density)). For example, when the recording density is 720 dpi and the length Lfp [mm] of the outer upper end Rfp is represented by the number of rasters, the number of rasters is ((Lfp [mm] /25.4) / (1/720 [ dpi])) can be rounded off to the nearest whole number.

  Similarly, in FIG. 7, the length Wa in the main scanning direction of the outer left end portion Rap of the printing paper with the material P1 and the postcard size is 1.5 mm. When the recording density of the raster in the main scanning direction and the recording density of the pixels in the main scanning direction are 720 dpi (dot / inch), the length Wa in the sub-scanning direction of the outer left end Rap is 1.5 mm. As shown in FIG. 9A, the outer left end Rap needs to be composed of 43 pixels. On the other hand, when the recording density of the raster and the recording density of the pixels in the main scanning direction are 1440 dpi, the length Lap in the sub-scanning direction of the outer left end Rap is 1.5 mm. As shown in FIG. 9B, the outer upper end Rfp needs to be configured with 85 pixels.

  That is, as shown in FIGS. 9A and 9B, the extended area table EAT (see FIG. 2) includes an outer upper end Rfp, an inner upper end Rfq, an outer lower end Rrp, and an inner lower end Rrq for each print mode. And the number of pixels of the outer left end Rap and the outer right end Rbp. The number of rasters constituting the edge of the same type of printing paper in each printing mode is a value such that the dimensions of the outer upper edge in the sub-scanning direction are substantially equal to each other. The same applies to the number of rasters in the inner upper end Rfq, outer lower end Rrp, inner lower end Rrq, and number of pixels in the outer left end Rap and outer right end Rbp. Here, the “type” of the printing medium (printing paper) is the same when the material of the printing medium is the same and the shape and dimensions are the same.

  The resolution conversion module 97 determines an extension area with reference to the extension area table EAT holding information in the form as shown in FIG. Then, the image data is converted into data that can record the extended area at a designated resolution. At that time, the length Lfp of the outer upper end Rfp, the length Lfq of the inner upper end Rfq, the length Lrp of the outer lower end Rrp, the length Lrq of the inner lower end Rrq, and the length of the outer left end Rap Since the width Wa and the width Wb of the outer right end Rbp are determined, the arrangement of the extended region R with respect to the printing paper P is also determined. This extended area table EAT corresponds to an “area size storage unit” in the claims. As hardware, a memory in which the extended area table EAT is stored corresponds to an “area size storage unit”. The resolution conversion module 97 functions as a “raster number determining unit” and a “pixel number determining unit” as defined in the claims in part of the processing. These functional units are shown as a raster number determining unit 97a and a pixel number determining unit 97b in FIG.

  FIG. 10 is an explanatory diagram showing the relationship between the lower end Pr of the printing paper P and the extended region R when the printing paper P is tilted. The arrangement of the printing paper P on which a solid line is assumed is shown, and the position of the printing paper P on which the one-dot chain line and the two-dot chain line are inclined is shown. When the printing paper P is inclined from the assumed posture on the platen, the amount of deviation of the end position of the printing paper P varies depending on the size of the printing paper P. That is, the case where the paper rotates clockwise will be described as an example. The positional deviation d1 of one corner of one side of the printing paper is d1 = Wp · sin θ1 when the position of the other end is used as a reference. Here, Wp is the length of one side of the paper, and θ1 is the size of the inclination angle of the paper. That is, the shift amount d1 is proportional to the length Wp of one side of the paper. The same applies to the deviation d2 when the sheet rotates counterclockwise.

  In the first embodiment, as shown in FIG. 7, the outer upper end Rfp, the inner upper end Rfq, the outer lower end Rrp, the inner lower end Rrq, the outer left end Rap, and the outer right end Rbp depend on the size of the printing medium. The size is determined. That is, the size of the extended region R and the arrangement with respect to the printing paper P are changed depending on the size of the printing medium. For this reason, even when the printing paper P is tilted from the assumed posture on the platen, the extended area so that the upper end Pf and the lower end Pr of the printing paper P are within the lower end Rr and the upper end Rf of the extended area R. The size of R and the arrangement with respect to the printing paper P can be determined. In FIG. 10, the lower end Pr of the printing paper P is within the lower end Rr (outer lower end Rrp + inner lower end Rrq) regardless of the orientation of the printing paper P. Therefore, no margin is formed at the edge of the printing paper P, and the platen is not stained with ink droplets.

  As described above, in the first embodiment, even when the printing paper P is inclined and a part of the lower end is shifted to the downstream side, there is little possibility that a margin is formed at the edge of the printing paper P. Even when a part of the printing paper P is shifted to the upstream side, the platen is less likely to be stained with ink droplets. In addition, by setting the recording area to an appropriate size with respect to the size of the printing paper P, by ejecting ink droplets to an area that is unnecessarily large with respect to the size of the printing medium, printing is performed. You can avoid wasting time.

  Here, the lower end Pr of the printing paper P has been illustrated and described, but the relationship between the expansion region R and the inclination of the printing paper P is the same for the upper end Pf side and the left and right ends Pa and Pb. However, for the upper end Pf side, the description about the shift to the upstream side and the description about the shift to the downstream side are interchanged. That is, even when the printing paper P is shifted to the upstream side, there is little possibility that a margin is formed at the end of the printing paper P. Even when the printing paper P is shifted to the downstream side, the platen is less likely to be stained with ink droplets.

  FIG. 11 is an explanatory diagram showing the relationship between the lower end Pr of the printing paper P and the extended region R when a deviation occurs in the sub-scan feed. The solid line indicates the arrangement of the printing paper P, and the one-dot chain line and the two-dot chain line indicate the position of the printing paper P when the sub-scan feed shifts. The deviation when the print medium is sent less than the assumed amount is d3, and the deviation when the print medium is sent more than the assumed amount is d4. When the material of the print medium is different, the amount of sub-scan feed deviation may be different. The amount of deviation differs depending on the slipperiness in the sub-scan of the print medium and the size of the print medium in the sub-scan direction.

  In the first embodiment, as shown in FIG. 7, the outer upper end Rfp, the inner upper end Rfq, the outer lower end Rrp, the inner lower end Rrq, the outer left end Rap, and the outer right end according to the material and dimensions of the printing medium. The size of Rbp is determined. That is, the size of the extended region R and the arrangement with respect to the printing paper P are changed according to the material and dimensions of the printing medium. For this reason, for each type of printing medium having a different material and size, an appropriate value is set so that the upper end Pf and the lower end Pr are within the lower end Rr and the upper end Rf of the extended region R even if the feeding of the printing paper P is shifted. The size of the extended region R and the arrangement with respect to the printing paper P can be determined. In FIG. 11, the lower end Pr of the printing paper P is within the lower end Rr (outer lower end Rrp + inner lower end Rrq) when the printing paper P is displaced in any direction. Therefore, no margin is formed at the edge of the printing paper P, and the platen is not stained with ink droplets.

  As described above, in the first embodiment, slippage is larger than expected in the sub-scanning, and even when the printing paper P is shifted to the downstream side, there is little possibility that a margin is formed at the end of the printing paper P. Even when the printing paper P is shifted to the upstream side, there is little possibility that the platen is stained with ink droplets. In addition, by ejecting ink droplets onto an unnecessarily large area on a printing medium that is accurately fed during sub-scan feeding, useless time is not used in printing. Here, the lower end Pr of the printing paper P has been illustrated and described, but the relationship between the extension region R and the sub-scan feed of the printing paper P is the same on the upper end Pf side.

  Further, as shown in FIGS. 9A and 9B, the extended area table EAT (see FIG. 2) includes an outer upper end Rfp, an inner upper end Rfq, an outer lower end Rrp, and an inner lower end for each printing mode. The number of Rrq rasters and the number of pixels at the outer left end Rap and the outer right end Rbp are stored. For this reason, the dimension of each part of the extended region R set beyond the edge of the printing paper P can be kept constant.

B3. Printing process steps:
FIG. 12 is a flowchart showing the user's procedure for the driver after the application program issues a print command. 13 and 14 are views showing windows for instructing the material of the printing paper. When the user instructs the application program 95 to print, the application program 95 issues a print command to the printer driver 96. Then, the printer driver 96 displays a “print” window on the CRT 21 (see FIG. 2). When the user clicks the “Printer Properties” icon from the “Print” window, a window as shown in FIG. 13 is displayed.

  In step S1 of FIG. 12, the user first selects the “basic setting” tab at the upper left of the plurality of tabs of the window of FIG. 13, and selects the paper type (material) in the “paper type” item. To do. In the window of FIG. 13, “paper type” means “material” of the printing paper in this specification. In FIG. 13, “plain paper” is selected. For example, if “photo print paper” is selected, the window shown in FIG. 13 is as shown in FIG.

  FIG. 15 is a diagram showing a window for instructing the recording density of an image. After selecting the printing paper, “Detailed setting” is checked in “Mode setting” in the middle of the window of FIG. Then, the window changes as shown in FIG. 15, and a recording density (print mode) window appears. In step S2 (see FIG. 12), for example, the user selects the “high definition” print mode as shown in FIG. When “high definition” is selected, printing is performed at a recording density higher than the normal recording density.

  In addition, when the user selects “recommended setting” without selecting “detailed setting” in “mode setting”, the user selects either “clean” or “fast” as shown in FIG. can do. Regardless of which is selected, the recording density remains normal, but when “fast” is selected, microweave printing is not performed and bidirectional printing is performed. On the contrary, when “clean” is selected, microweave printing is performed, and unidirectional printing is performed (bidirectional printing is not performed). “Microweave printing” is also referred to as “overlap printing”, and is a printing method in which pixels in one raster are printed using different nozzles in a plurality of main scans. “Unidirectional printing” is a printing method in which dots are formed only by main scanning in one direction, and “bidirectional printing” is a printing method in which dots are formed by reciprocating main scanning. In the first embodiment, the number of rasters and the number of pixels in the extended area are set in accordance with the recording density of the pixels (see FIG. 9). It is also possible to set the number of pixels.

  FIG. 16 is a diagram showing a window for instructing the size of the printing paper. After selecting the print mode in step S2, the user selects the second “paper setting” tab from the left end in step S3, and selects the paper size in the “paper size” item as shown in FIG. To do. In FIG. 16, “A4” is selected.

  Thereafter, the “OK” icon at the bottom of the window in FIG. 16 is clicked, and the “OK” icon in the “Print” window is clicked. Then, the printer driver 96 starts resolution conversion by the resolution conversion module 97, and printing is executed (step S4). The instructions in steps S1 to S3 described above are not limited to the order shown in FIG. 12, and may be performed in the order of step S2, step S1, and step S3. That is, if the paper material, size, and print mode are instructed before printing is performed, the order of the instruction may be any. A user interface screen for each instruction (selection) to the printer driver 96 by the user as shown in FIGS. 13 to 16 is displayed on the CRT 21 by the printer driver 96. That is, the printer driver 96 functions as a “user interface unit” in the claims. The “user interface unit” as the function unit is shown as a user interface unit 96a in FIG. Each instruction (selection) to the printer driver 96 by the user through the user interface screen is made through the keyboard 14 (see FIG. 2) in addition to the mouse 13. That is, the mouse 13 and keyboard 14 function as an input unit.

B4. Dot formation:
(I) Upper end processing:
FIG. 17 is an explanatory diagram showing how each raster is recorded by which nozzle in the vicinity of the upper end (front end) of the printing paper. Here, in order to simplify the description, description will be made using only one nozzle row. One nozzle row has eight nozzles. During main scanning, each nozzle is responsible for recording one raster. Here, the “raster” is a column of pixels arranged in the main scanning direction. The “pixel” is a square grid virtually defined on the print medium in order to define the position where the ink droplet is landed and the dot is recorded. Here, it is assumed that the nozzles are arranged at intervals of 3 rasters.

  In FIG. 17, one row of cells arranged vertically represents the print head 28. Numbers 1 to 8 in each square indicate nozzle numbers. In the specification, “#” is added to these numbers to represent each nozzle. In FIG. 17, the print heads 28 that are relatively sent with time in the sub-scanning direction are sequentially shifted from left to right. As shown in FIG. 17, in the upper end process, the sub-scan feed for each dot is repeated seven times. Note that “dot” as a unit of the sub-scan feed amount means a pitch of one dot corresponding to the print resolution in the sub-scan direction, and this is equal to the raster pitch.

  Thereafter, the process shifts to intermediate processing, and the feeding of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order. A method of performing sub-scanning by combining different feed amounts in this way is called “anomalous feed”. When the sub-scan feed as described above is performed, each raster is recorded by two nozzles except for some rasters. That is, in this embodiment, each raster is printed by two nozzles. For example, in FIG. 17, the fifth raster from the top is recorded by the # 2 nozzle and the # 1 nozzle. At this time, the # 2 nozzle records, for example, even address pixels, and the # 1 nozzle records odd address pixels. The ninth raster from the top is recorded by the # 3 nozzle and the # 2 nozzle. In this manner, a method of printing by sharing pixels in one raster by a plurality of nozzles is called “overlap printing”. In overlap printing, a single raster is recorded with dots by a plurality of nozzles passing over the raster in a plurality of main scans at different positions in the sub-scanning direction of the printing paper with respect to the print head.

  On the other hand, in FIG. 17, the four rasters from the top are only passed once by the # 1 nozzle in the main scan during printing. Therefore, for these rasters, it is not possible to print by sharing pixels with two nozzles. Therefore, in this embodiment, these four rasters are not used for recording an image. That is, the rasters that can be used to record an image in the present embodiment are the fifth and subsequent rasters from the upstream end in the sub-scanning direction among the rasters in which the nozzles on the print head 28 can record dots. A raster area that can be used to record this image is called a “printable area”. A raster area that is not used for image recording is referred to as a “non-printable area”. In FIG. 17, numbers assigned in order from the top with respect to rasters on which the nozzles on the print head 28 can record dots are shown on the left side of the drawing. Hereinafter, the same applies to the drawings describing the dot recording of the upper end processing. In the figure, nozzles surrounded by a thick frame are nozzles that record dots on a raster.

  In FIG. 17, the 13th and 15th rasters from the top pass through three nozzles in the main scanning during printing. For such a raster in which three or more nozzles pass during printing, only two of the nozzles record dots. These rasters are preferably recorded by nozzles that pass over the raster after having moved to intermediate processing as much as possible. In the intermediate processing, irregular feeding is performed, and the combination of nozzles passing on adjacent rasters is different, so that the printing result is higher in image quality than the upper end processing in which regular feeding is performed dot by dot. Because it can be expected.

  In this embodiment, an image is recorded without a margin up to the upper end of the printing paper. As described above, in the present embodiment, among the rasters on which the nozzles on the print head 28 can record dots, the fifth and subsequent rasters (printable areas) from the upstream end in the sub-scanning direction are used to generate an image. Can be recorded. Therefore, if the printing paper is arranged with respect to the print head 28 and the dot recording is started so that the fifth raster from the end is positioned at a position just above the upper edge of the printing paper, theoretically, Images can be recorded up to the top of the printing paper. However, an error may occur in the feed amount during the sub-scan feed. In addition, the ejection direction of the ink droplets may be shifted due to a manufacturing error of the print head. For such a reason, it is preferable that no margin is generated at the upper end of the printing paper even when the landing position of the ink droplet on the printing paper is deviated. Therefore, in this embodiment, the image data D used for printing is set from the fifth raster from the upstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots. It is assumed that printing starts from a state in which the upper end of the sheet P is at the seventh raster position from the upstream end in the sub-scanning direction. Therefore, the assumed position of the upper end of the printing paper for each raster at the start of printing is the position of the seventh raster from the upstream end in the sub-scanning direction, as shown in FIG.

  That is, in the present embodiment, the width Lfp of the outer upper end portion Rfp (see FIG. 6) of the extended region R set beyond the upper end Pf of the printing paper P to the outside of the printing paper P is two rasters. Similarly, the width Lrp of the outer lower end portion Rrp (see FIG. 6) of the extended region R set to the outside of the print paper P beyond the lower end Pr of the print paper P is also two rasters. The lower end side will be described in detail later.

  FIG. 18 is a side view showing the relationship between the print head 28 and the printing paper P at the start of printing. Here, the central support portion 26c of the platen 26 is provided in a range R26 from a position two rasters behind the # 2 nozzle of the print head 28 to a position two rasters ahead from the # 7 nozzle. It is assumed that Therefore, even when ink droplets Ip are ejected from each nozzle in the absence of printing paper, ink droplets from the nozzles # 1, # 2, # 7, and # 8 do not land on the platen 26.

  In FIG. 5, the portion of the nozzle group Nr indicated by the diagonal lines of the print head 28 is the portion where the nozzles # 1 and # 2 are located. A downstream groove 26r is provided below the portion through which these nozzles pass during main scanning, and when the upper end Pf of the printing paper P is at the position indicated by the alternate long and short dash line on the downstream groove 26r, Printing starts.

  As described above, at the start of printing, the upper end Pf of the printing paper P is at the position of the seventh raster from the upstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots. In other words, referring to FIG. 18, the upper end of the printing paper P is at a position 6 rasters behind the # 1 nozzle. In FIG. 18, the raster position assumed on the image data is indicated by a broken line. Therefore, if printing is started from this state, the uppermost raster in the printable area (the fifth raster from the top in FIG. 17) should be recorded by the nozzle # 2. There is still no printing paper P below the second nozzle. Therefore, if the printing paper P is accurately fed by the upstream paper feed rollers 25a and 25b, the ink droplet Ip ejected from the # 2 nozzle will fall into the downstream groove 26r as it is. Further, as shown in FIG. 17, the uppermost raster in the printable area is also recorded by the # 1 nozzle after four 1-dot feeds. However, similarly, at the stage where four 1-dot feeds are performed, there is still no print paper P below the # 1 nozzle. Therefore, the ink droplet Ip ejected from the nozzle # 1 at that time also falls into the downstream groove 26r as it is. The same applies to the case where the second raster from the top of the printable area (the sixth raster from the top in FIG. 17) is recorded.

  However, when the printing paper P is fed more than the original feed amount for some reason, the upper end of the printing paper P is the second raster from the top of the printable area or the topmost of the printable area. Sometimes it comes to the raster position. The same applies to the case where the print sheet is inclined and one of the left and right ends is positioned downstream of the assumed position in the sub-scanning direction. In this embodiment, even in such a case, the nozzles # 1 and # 2 eject ink droplets Ip to those rasters (outer upper end Rfp set at a position exceeding the upper end Pf of the printing paper P). Therefore, an image can be recorded on the upper end of the printing paper P, and no margin is generated. That is, even when the printing paper P is fed more than the original feeding amount, as shown by the alternate long and short dash line in FIG. 18, if the extra feeding amount is 2 rasters or less, the printing paper P There will be no white space at the top edge. An area corresponding to two rasters set outside the upper end of the printing paper P is an outer upper end portion Rfp of the image recording area. Further, the CPU 41 causes the CPU 41 to perform printing in the region (extended region R) beyond the upper end Pf of the printing paper P in this way. In other words, it is the CPU 41 that defines the position of the extended region R with respect to the print paper P and causes the print paper P to be sub-scanned while ejecting ink droplets to the extended region R. That is, the CPU 41 functions as an “edge printing unit” in the claims.

  Conversely, it is also conceivable that the printing paper P is fed less than the original feed amount for some reason. In such a case, there is no printing paper at the position where the printing paper should originally be, and the ink droplet Ip will land on the structure below. The same applies to the case where there is no printing paper at the position where the printing paper should originally exist because the printing paper P is inclined. However, as shown in FIG. 17, in this embodiment, two rasters are recorded by the nozzles # 1 and # 2 from the assumed upper end position of the paper. Downstream of these nozzles, a downstream groove 26r is provided. Even if the ink droplet Ip does not land on the printing paper P, the ink droplet Ip falls into the downstream groove 26r, and the absorbing member 27r. Will be absorbed. Therefore, the ink droplet Ip does not land on the upper surface portion of the platen 26 and the printing paper is not soiled later. That is, in this embodiment, even when the upper end Pf of the printing paper P is behind the assumed upper end position at the start of printing, if the deviation amount from the assumed upper end position is 2 rasters or less, the ink droplet Ip Will land on the upper surface of the platen 26 and will not stain the printing paper P later. Inside the upper end of the printing paper P, an area for two rasters recorded by the nozzles on the downstream groove 26r is an inner upper end Rfq of the image recording area.

  As described above, at the time of sub-scanning, the upper end Pf of the printing paper P is on the opening of the downstream groove 26r, and the upper end Pf is at a position upstream of the downstream end nozzle in the sub-scanning direction. It is the CPU 41 that sets the position of the printing paper P in the sub-scanning direction. That is, the CPU 41 functions as an upper end positioning unit.

(Ii) Bottom edge processing:
FIG. 19 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end processing. FIG. 19 shows from the time when the (n + 1) th sub-scan feed is performed until the last n + 17th sub-scan feed. In the present embodiment, as shown in FIG. 19, after the sub-scan feed up to the (n + 8) th sub-scan feed in the intermediate process, the feed of 5 dots, 2 dots, 3 dots and 6 dots is repeated in that order, and then the last 9 Sub-scan feed from the (n + 9) th time to the (n + 17) th time is performed by sending one dot at a time. As a result, each raster along the main scanning direction is recorded by two nozzles except for some rasters. In FIG. 19, numbers assigned in order from the bottom are shown on the right side of the drawing for rasters on which dots on the print head 28 can record dots. Hereinafter, the same applies to the drawings describing the dot recording in the lower end processing.

  In FIG. 19, the four rasters from the bottom are only passed once by the # 8 nozzle in printing. The fifth or more rasters from the bottom can be recorded by two or more nozzles. Accordingly, the printable area in the lower end portion of the printing paper is the fifth or more raster area from the bottom.

  In FIG. 19, the ninth and tenth rasters from the bottom pass through three or more nozzles in the main scanning during printing. For such a raster in which three or more nozzles pass during printing, it is preferable to perform recording in the intermediate process as much as possible and to record with a nozzle that passes over the raster. This is because the printing result can be expected to have a higher image quality than the lower end processing in which regular feeding is performed for each dot.

  In this embodiment, as in the case of the upper end, an image is recorded with no margin at the lower end. As described above, in this embodiment, among the rasters on which the nozzles on the print head 28 can record dots, the fifth or more raster (printable area) from the downstream end in the sub-scanning direction is used to generate an image. Can be recorded. However, in consideration of a case where an error occurs in the feed amount during the sub-scan feed, the recording is performed on the printing paper from the seventh raster from the downstream end in the sub-scan direction. That is, the lower end of the extended region R is the fifth raster from the downstream end in the sub-scanning direction, whereas the lower end Pr of the printing paper P is at the seventh raster position from the upstream end in the sub-scanning direction. It is said. An extended area R for two rasters set beyond the lower end Pr of the printing paper P is an outer lower end portion Rrp. In the first embodiment, since the dots for forming an image are arranged for all the pixels in the printable area, the extended area R and the printable area coincide with each other.

  FIG. 20 is a plan view showing the relationship between the upstream groove 26f and the printing paper P when the lower end portion Pr of the printing paper P is printed. In FIG. 20, the nozzle group Nf of the portion indicated by the oblique lines of the print head 28 is the portion where the nozzles # 7 and # 8 are located. An upstream groove 26f is provided below the portion through which these nozzles pass during main scanning, and when the lower end Pr of the printing paper P is at the position indicated by the alternate long and short dash line on the upstream groove 26f, The dot recording on the actual printing paper P is finished.

  FIG. 21 is a side view showing the relationship between the print head 28 and the print paper P when the lower end portion Pr of the print paper P is printed. When ink droplets are ejected to the lower end Pr of the printing paper P, the printing paper P is supported by the platen 26, the lower end is over the opening of the upstream groove 26f, and the lower end Pr of the printing paper P is The printing paper P is disposed at a position downstream of the nozzle # 8 in the sub-scanning direction. As described above, the lower end Pr of the printing paper P is arranged at the position of the seventh raster from the downstream end in the sub-scanning direction among the rasters on which the nozzles on the print head 28 can record dots (see FIG. 19). ). Therefore, after the raster at the lower end of the printing paper P is recorded, the lowest raster in the printable area (extended area R) and the second raster from the bottom (the sixth and fifth raster from the bottom in FIG. 19) are recorded. As a result, the ink droplets Ip ejected from the nozzles # 7 and # 8 fall into the upstream groove 26f as they are.

  Even if the printing paper P is fed less than the original feed amount for some reason (in the case of the one-dot chain line in FIG. 11), the nozzles # 7 and # 8 are the fifth and sixth rasters from the bottom. On the other hand, since the ink droplet Ip is ejected (at a position beyond the lower end Pr of the printing paper P), an image can be recorded on the lower end Pr of the printing paper P, and no margin is formed. The same applies to the case where the printing paper is inclined and one of the left and right ends is positioned upstream of the assumed position in the sub-scanning direction (in the case of the dashed line in FIG. 10). That is, as indicated by the alternate long and short dash line in FIG. 21, when the insufficient feed amount or positional deviation is equal to or less than two rasters, no margin is formed at the lower end of the printing paper P. An area corresponding to two rasters set outside the lower end of the printing paper is an outer lower end Rrp of the image recording area. In addition, the CPU 41 causes the CPU 41 to print in the area (extended area R) beyond the lower end Pr of the printing paper P in this way. That is, the CPU 41 functions as an end printing unit.

  The four rasters above the assumed upper end position of the paper (the seventh to tenth rasters from the bottom in FIG. 19) are recorded by the # 7 and # 8 nozzles. Therefore, even when the printing paper P is fed more than the original feeding amount for some reason (in the case of the two-dot chain line in FIG. 11), the ejected ink droplet Ip falls into the upstream groove 26f. No landing on the upper surface of the platen 26. The same applies to the case where the printing paper is inclined and one of the left and right ends is positioned downstream of the assumed position in the sub-scanning direction (in the case of the two-dot chain line in FIG. 10). On the inner side of the lower end of the printing paper P, an area corresponding to four rasters recorded by the nozzles on the upstream groove 26f is an inner lower end Rrq of the image recording area.

  As described above, at the time of sub-scanning, the lower end Pr of the printing paper P is above the opening of the upstream groove 26f, and the lower end Pr is at a position downstream of the upstream end nozzle in the sub-scanning direction. It is the CPU 41 that sets the position of the printing paper P in the sub-scanning direction. That is, the CPU 41 functions as a lower end positioning unit.

(Iii) Left and right side edge printing:
FIG. 22 is an explanatory diagram showing printing of the left and right end portions of the printing paper P. In the present embodiment, printing is performed so that no margin is provided at the left and right edges of the printing paper P throughout the entire recording of the image on the printing paper P, including the upper edge processing and the lower edge processing. At that time, in the main scanning, the print head 28 is sent to a position where all the nozzles are located outside the print paper P beyond the end of the print paper P for one end, and also for the other end. All nozzles are fed beyond the other end of the printing paper P to a position outside the printing paper P. The image data is not only when the nozzle Nz is on the printing paper P, but also when the nozzle Nz is at a position beyond the end of the printing paper P and on the left groove 26a or the right groove 26b. Ink droplets are ejected to the expansion region R according to D. Here, the width Wr of the extended region R, which is an image recording region, has a width that exceeds the left and right widths of the printing paper P, and does not exceed the distance between the outer side walls of the left groove portion 26a and the right groove portion 26b. Width. Therefore, by ejecting ink droplets from the nozzle Nz according to the image data D, the nozzle Nz is located at a position beyond the end of the printing paper P and also on the left groove 26a or the right groove 26b. Ink droplets are discharged.

  By performing such printing, even when the printing paper P is slightly displaced in the main scanning direction, an image can be formed without creating margins on the left and right ends of the printing paper P. Further, since the nozzles for printing both side edges of the printing paper are nozzles located on the left groove 26a or the right groove 26b, the ink drops are supported by the center of the platen 26 even when the ink drops are separated from the printing paper P. Without landing on the portion 26c, it lands on the left groove portion 26a or the right groove portion 26b. Therefore, the printing paper P is not soiled by ink droplets that have landed on the central support portion 26c of the platen 26.

  Here, the printing paper having the maximum width in the main scanning direction among the printing papers usable in the printer 22 has been described as an example, but the same applies to a printing paper having a narrower width. That is, for narrower printing paper, the guides 29a and 29b (the left and right edges of the printing paper are positioned on the left groove 26a and the right groove 26b2 or the left groove 26a and the right groove 26b3. Is set). The ink is not only when the nozzle Nz is on the printing paper P but also at a position beyond the edge of the printing paper P and on the left groove 26a, the right groove 26b2, or the right groove 26b2. Discharge drops.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
In the first embodiment, the print medium is plain paper, photo print paper, a dedicated glossy film, a dedicated OHP sheet or the like, but the print medium is not limited to this. For example, it may be a fabric or may have a certain rigidity such as CD-R. The shape of the print medium may also be a circular shape such as a CD-R, and is not limited to a rectangle. In that case, the groove on the platen is preferably provided according to the shape of each print medium, and the number of pixels of each raster constituting the expansion region is preferably set according to the shape of the print medium. In other words, the print medium may be anything as long as it can record an image using a dot forming element.

C2. Modification 2:
In the first embodiment, only one left groove is provided, and a plurality of right grooves are provided according to the width of the print medium (see FIGS. 5 and 20). The print medium was formed with dots such that one side end was on the left groove, regardless of its width. However, only one right groove portion may be provided, and a plurality of left groove portions may be provided according to the width of the print medium. Moreover, it is good also as having multiple sets of the left side groove part and the right side groove part according to the width | variety of a printing medium. That is, a plurality of second groove portions provided at substantially equal intervals to the width of the print medium can be provided in accordance with the type of width of the print medium that can be used in the printing apparatus. The groove can be implemented in various ways.

C3. Modification 3:
In the first embodiment, the upstream groove 26f is provided at a position facing a part of the upstream nozzle group Nf (see FIG. 20) including the most upstream nozzle among the nozzles on the print head 28. The downstream groove 26r is provided at a position facing a part of the downstream nozzle group Nr (see FIG. 5) including the most downstream nozzle among the nozzles Nz on the print head 28. However, the relationship between the nozzle and the groove is not limited to this. For example, a nozzle group may be provided further upstream of the upstream groove portion 26f, and an upstream support portion of the platen may be provided at a position facing the nozzle group. By doing so, the possibility that the front end portion (upper end portion) of the print medium sent from the upstream falls into the upstream groove portion is reduced. Similarly, a nozzle group may be provided further downstream of the downstream groove portion 26r, and a downstream support portion of the platen may be provided at a position facing the nozzle group.

  FIG. 23 is a plan view showing the relationship between the groove 26m and the printing paper P when the upper end portion Pf of the printing paper P is printed in the printing apparatus of the modified example. In the first embodiment, the groove on the platen is provided with an upstream groove 26f and a downstream groove 26r, and the nozzle group Nr facing the downstream groove 26r prints the upper end of the printing paper P, and the upstream The nozzle group Nf facing the side groove portion 26f printed the lower end portion of the printing paper P. However, the groove on the platen is not limited to such an embodiment, and an embodiment in which one groove is provided on the platen may be used. In such an aspect, the upper end portion and the lower end portion of the printing paper P are printed by the nozzle group Nm located at a position facing one groove portion 26m provided on the platen. In such an aspect, it is easy to widely provide the upstream support portion 26sf and the downstream support portion 26sr provided on the upstream side and the downstream side of the groove portion in the sub-scanning direction.

C4. Modification 4:
In the first embodiment, regular feeding of one dot is performed in the upper end process and the lower end process. However, the feeding of the upper end processing and the lower end processing is not limited to this, and 2-dot, 4-dot, 5-dot regular feed or irregular feed can be used according to the number of nozzles in the nozzle row and the nozzle pitch. . That is, any feed may be used as long as the maximum sub-scan feed amount is smaller than the maximum sub-scan feed amount in the intermediate process. However, the smaller the feed amount of the sub-scan feed of the upper end process, the more the upper end of the printing paper can be recorded with the nozzle on the downstream side in the sub-scan direction. Therefore, the downstream groove can be made narrower, and the upper surface of the platen that supports the printing paper can be widened. Similarly, the lower the sub-scan feed amount of the lower end process, the higher the upper-side nozzle can record the upper end of the printing paper. Therefore, the upstream groove can be made narrower, and the upper surface of the platen that supports the printing paper can be widened.

  Further, the feed in the intermediate process is not limited to the irregular feed in which the feed of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order. For example, in the configuration shown in the first embodiment, 5 dots, 3 dots, 2 dots, and 6 dots may be fed. Also, other combinations of feed amounts can be adopted according to the number of nozzles, nozzle pitch, etc., and regular feeds of other feed amounts may be performed. That is, any sub-scan feed may be performed as long as the maximum sub-scan feed amount is larger than the maximum sub-scan feed amount in the upper end process or the lower end process.

C5. Modification 5:
In the above embodiment, both the upper end process and the lower end process are executed, but only one of them may be executed as necessary. Further, the printing apparatus according to the present embodiment includes the upstream groove portion 26f and the downstream groove portion 26r on the upstream side and the downstream side of the platen 26 in the sub-scanning direction, respectively, but may include only one of them. .

  In the above embodiment, printing is performed without margins on the left and right side edges of the printing paper P, but only one of them may be executed as necessary.

C6. Modification 6:
The present invention can be applied not only to color printing but also to monochrome printing. The present invention can be applied not only to an ink jet printer but also to a dot recording apparatus that performs recording on the surface of a printing medium using a recording head having a plurality of dot forming element arrays. Here, “dot forming element” means a component for forming dots, such as an ink nozzle in an ink jet printer.

C7. Modification 7:
In the above embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware. For example, the host computer 90 can execute part of the functions of the CPU 41 (FIG. 3).

  A computer program for realizing such a function is provided in a form recorded on a computer-readable recording medium such as a floppy disk or a CD-ROM. The host computer 90 reads the computer program from the recording medium and transfers it to the internal storage device or the external storage device. Or you may make it supply a computer program to the host computer 90 from a program supply apparatus via a communication path. When realizing the function of the computer program, the computer program stored in the internal storage device is executed by the microprocessor of the host computer 90. Further, the host computer 90 may directly execute the computer program recorded on the recording medium.

  In this specification, the host computer 90 is a concept including a hardware device and an operation system, and means a hardware device that operates under the control of the operation system. The computer program causes the host computer 90 to realize the functions of the above-described units. Note that some of the functions described above may be realized by an operation system instead of an application program.

  In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but an internal storage device in a computer such as various RAMs and ROMs, An external storage device fixed to a computer such as a hard disk is also included.

FIG. 3 is an explanatory diagram showing a relationship between a printing paper and an area where an image is formed in the embodiment of the present invention. FIG. 3 is a block diagram illustrating a software configuration of the printing apparatus. 2 is an explanatory diagram illustrating a schematic configuration of a printer 22. FIG. FIG. 4 is a plan view illustrating an example of an arrangement of nozzle units for each color in the print head unit 60. FIG. 3 is a plan view showing the periphery of a platen 26. 3 is an explanatory diagram showing a relationship between an image recording region R and a printing paper P. FIG. The table | surface which shows the example of the dimension of outer upper end part Rfp, inner upper end part Rfq, outer lower end part Rrp, inner lower end part Rrq, outer left end part Rap, and outer right end part Rbp. FIG. 3 is an explanatory diagram showing a relationship between a printing paper for each type of printing paper and a region where an image is formed. The table | surface which shows the example of the raster number of the part of an extended area | region and the number of pixels which are set exceeding the edge of four sides of the printing paper P. FIG. FIG. 3 is an explanatory diagram illustrating a relationship between a lower end Pr of the printing paper P and the extended region R when the printing paper P is inclined. FIG. 3 is an explanatory diagram showing a relationship between a lower end Pr of a printing paper P and an extended region R when a deviation occurs in sub-scan feed. The flowchart which shows the user's procedure with respect to a driver after an application program issues a printing command. The figure which shows the window which instruct | indicates the material of printing paper. The figure which shows the window which instruct | indicates the material of printing paper. The figure which shows the window which instruct | indicates the recording density of an image. The figure which shows the window which instruct | indicates the size of printing paper. Explanatory drawing which shows how each raster is recorded by which nozzle in the vicinity of the upper end (front end) of the printing paper. FIG. 4 is a side view showing the relationship between the print head and the printing paper P at the start of printing. Explanatory drawing which shows how each raster is recorded by which nozzle in a lower end process. The top view which shows the relationship between the upstream groove part 26f and the printing paper P at the time of printing the lower end part Pr of the printing paper P. FIG. FIG. 4 is a side view showing the relationship between the print head and the print paper P when printing the bottom end of the print paper. FIG. 3 is an explanatory diagram illustrating printing of left and right end portions of the printing paper P. The top view which shows the relationship between the groove part 26m and the printing paper P at the time of printing the upper end part Pf of the printing paper P in the printing apparatus of a modification. The side view which shows the periphery of the print head of the conventional printer.

Explanation of symbols

12 ... Scanner 13 ... Mouse 14 ... Keyboard 21 ... CRT
DESCRIPTION OF SYMBOLS 22 ... Printer 23 ... Paper feed motor 24 ... Carriage motor 25a, 25b ... Upstream paper feed roller 25c, 25d ... Downstream paper feed roller 25p, 25q ... Upstream paper feed roller 25r, 25s ... Downstream paper feed roller 26 ... Platen 26a ... Left groove 26b, 26b2, 26b3 ... Right groove 26c ... Center support 26f ... Upstream groove 26m ... Groove 26o ... Platen 26r ... Downstream groove 26sf ... Upstream support 26sr ... Downstream support 27 ... Absorbing member 27f, 27r ... absorbing member 28, 28o ... print head 29a, 29b ... guide 31 ... carriage 32 ... operation panel 34 ... sliding shaft 36 ... drive belt 38 ... pulley 39 ... position detection sensor 40 ... control circuit 41 ... CPU
42 ... PROM
43 ... RAM
44 ... Drive buffer 45 ... PC interface 60 ... Print head unit 61-66 ... Ink ejection head 67 ... Introducing pipe 71 ... Cartridge 72 ... Color ink cartridge 90 ... Host computer 91 ... Video driver 95 ... Application program 96 ... Printer Driver 97 ... Resolution conversion module 97a ... Raster number determination unit 97b ... Pixel number determination unit 98 ... Color correction module 99 ... Halftone module 100 ... Rasterizer A ... Arrow D ... Image data DT ... Dot formation pattern table EAT ... Expansion area table Ip ... Ink droplet LUT ... Color correction table Nf ... Nozzle group Nm ... Nozzle group Nr ... Nozzle group Nz ... Inkjet nozzle ORG ... Original color image data P ... Print paper PD ... Print data Pa ... For printing Of the left end (part)
Pb: Right edge (part) of printing paper
Pf: Upper edge (part) of printing paper
Pr: Lower end (part) of printing paper
R ... Extended area (recording area)
R26: Range of the central support portion Rap: Outer left end portion of the expansion region Rbp: Outer right end portion of the expansion region Rf: Upper end portion of the expansion region Rfp: Outer upper end portion of the expansion region Rfq: Inner upper end portion of the expansion region Rr: Expansion region Lower end Rrp ... outer lower end of extended region Rrq ... inner lower end of extended region k ... nozzle pitch

Claims (4)

In a dot recording apparatus having a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets, a print medium is moved relative to the dot recording head and conveyed, and among the plurality of dot forming elements A dot recording method in which at least a part of the ink is driven to eject ink droplets based on print data, and dots are recorded on the print medium without margins on the edge,
In the case where the downstream end in the transport direction of the print medium is the first end and the upstream end is the second end, the ink droplets are applied to the first end and the region beyond the first end. To record dots at the first end, and to record dots at the second end by discharging the ink droplets to the second end and the area beyond the second end. And a step in which the size of the region in which the ink droplets are ejected beyond the second end in the transport direction of the print medium exceeds the first end of the region in which the ink droplets are ejected. A dot recording method, wherein the ink droplets are ejected so as to be larger than a dimension in a transport direction. A dot recording device for recording dots on a printing medium without margins at the edges,
A dot recording head provided with a plurality of dot forming elements for discharging ink droplets;
A transport unit that transports the print medium relative to the dot recording head;
A head driver that drives at least some of the plurality of dot forming elements to eject ink droplets;
In the case where the downstream end in the transport direction of the print medium is the first end and the upstream end is the second end, the ink droplets are applied to the first end and the region beyond the first end. Is ejected to perform dot recording at the first end, and the ink droplets are ejected to the second end and the region beyond the second end to perform dot recording at the second end. In addition, the dimension in the transport direction of the print medium in the area where the ink droplets are ejected beyond the second end is larger than the dimension in the transport direction of the area where the ink droplets are ejected beyond the first end. A control unit for ejecting the ink droplets,
A dot recording apparatus comprising: In a dot recording apparatus having a dot recording head provided with a plurality of dot forming elements for ejecting ink droplets, a print medium is moved relative to the dot recording head and conveyed, and among the plurality of dot forming elements A dot recording method in which at least a part of the ink is driven to eject ink droplets based on print data, and dots are recorded on the print medium without margins on the edge,
When the downstream end in the transport direction of the print medium is the first end and the upstream end is the second end, the print data having a width exceeding the first and second ends is A step of positioning with respect to the print medium, a step of ejecting the ink droplets to the first end and a region beyond the first end, and recording a dot on the first end, and the second And ejecting the ink droplets to an area beyond the second end to record dots on the second end, and among the ejection areas of the ink droplets based on the print data, The dot recording method, wherein the positioning is performed so that a dimension in a conveyance direction of the print medium in a portion exceeding the second end is larger than a dimension in a conveyance direction of a portion exceeding the first end. A dot recording device for recording dots on a printing medium without margins at the edges,
A dot recording head provided with a plurality of dot forming elements for discharging ink droplets;
A transport unit that transports the print medium relative to the dot recording head;
A head driver that drives at least some of the plurality of dot forming elements to eject ink droplets;
When the downstream end in the print medium transport direction is the first end and the upstream end is the second end, print data having a width exceeding the first and second ends is printed. In addition to positioning with respect to the medium, the ink droplets are ejected to the first end and a region beyond the first end to record dots on the first end, and the second end and the A controller that discharges the ink droplets to a region beyond the second end and records dots on the second end; and
In the ejection region of ink droplets based on the print data, the dimension in the transport direction of the print medium of the portion exceeding the second end is larger than the dimension in the transport direction of the portion exceeding the first end. The dot recording apparatus, wherein the controller performs the positioning.

Images