JP4826653B2 - Dot recording device - 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. 20 is a side view showing the periphery of a 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.
Further, efficient printing is not considered when an image is printed without margins to the edge of the printing paper.

Japanese Patent Laid-Open No. 2000-118058

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

In order to deal with at least a part of the above-described problems, the present invention can employ the following aspects.
[Application Example 1]
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;
A platen that supports the print medium so as to face the dot recording head;
A control unit for controlling the head drive unit and the transport unit;
The platen is
A groove for receiving ink droplets detached from the print medium;
A dot recording apparatus comprising: an upstream support portion that is positioned on the upstream side of the groove portion in the transport direction and is positioned so as to face a part of the dot forming elements among the plurality of dot forming elements.
[Application Example 2]
A dot recording apparatus according to Application Example 1,
The control unit, when ejecting ink droplets to the downstream end in the transport direction of the print medium, the print medium is supported by the platen, and the downstream end is located above the groove, In addition, the dot recording apparatus sets the position of the print medium in the transport direction so that the downstream end in the transport direction is positioned upstream of the dot forming element.
[Application Example 3]
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;
A platen that supports the print medium so as to face the dot recording head;
A control unit for controlling the head drive unit and the transport unit;
The platen is
A groove for receiving ink droplets detached from the print medium;
A dot recording apparatus comprising: a downstream support portion that is positioned on the downstream side of the groove portion in the transport direction and is positioned to face a part of the dot formation elements among the plurality of dot formation elements.
[Application Example 4]
A dot recording apparatus according to Application Example 3,
The control unit, when ejecting ink droplets to an upstream end in the transport direction of the print medium, the print medium is supported by the platen, and the upstream end is located above the groove, In addition, the dot recording apparatus sets the position of the print medium in the transport direction so that the upstream end in the transport direction is positioned downstream of the dot forming element.
Moreover, in order to deal with at least a part of the above-described problems, the present invention can adopt the following aspects. That is, a predetermined process is performed for 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. 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 main scanning path, and a main scanning medium between the main scannings A sub-scanning driving unit that performs sub-scanning by driving in a direction crossing the direction of the above, 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 elements in at least a part of the main scanning path, and at least some of the dot forming elements among the plurality of dot forming elements And a groove provided at a position facing each other.

  When forming dots by such a dot recording apparatus, an extended area that is a recording area of an image to be recorded on a print medium and has a length exceeding at least the upper and lower ends of the print medium is determined according to the type of the print medium. Determine. Then, print data for recording an image over the extended area is prepared. Thereafter, when printing at least one of 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 groove portion.

  According to such an aspect, it is possible to perform printing without margins up to the edge of the printing paper without landing ink droplets on the platen. Then, by setting the expansion area to a necessary and sufficient size according to the type of the print medium, ink droplets are ejected to an area that is unnecessarily large with respect to the size of the print medium, and wasted time is used for printing. You can prevent it from happening.

  The type of print medium is preferably determined according to the dimensions of the print medium. When the print medium is inclined from the assumed posture, the positional deviation of the end portion of the print medium increases as the size of the print medium increases. Therefore, by setting the expansion area according to the type related to the size of the print medium, the expansion area is appropriately set so that printing can be performed without a margin to the edge of the printing paper without landing ink droplets on the platen. Can be determined.

  It is also preferable that the type of print medium is determined according to the material of the print medium. The feed error during the sub-scanning of the print medium may vary depending on the type of print medium. Therefore, by defining the expansion area according to the type of the material of the print medium, the expansion area is appropriately determined so that printing can be performed without a margin up to the edge of the printing paper without landing ink droplets on the platen. be able to.

  When ejecting ink droplets to the extended region, the following is preferable. That is, 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 above the opening of the groove, and the upper end is the downstream end in the sub-scanning direction. The position of the print medium in the sub-scanning direction is set so that it is positioned upstream of the dot forming element in the sub-scanning direction. Further, 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 above the opening of the groove, and the lower end of the print medium is in the sub-scanning direction. The position of the print medium in the sub-scanning direction is set so that it is positioned downstream of the upstream dot forming element 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.

  The platen is further provided in a range including at least the landing range of the ink droplets from the plurality of dot forming elements in the sub-scanning direction, and a pair of side grooves provided at an interval substantially equal to the width of the printing medium. If so, it is preferable to do the following when preparing print data. That is, print data for recording an image over an extended region having a width exceeding the left and right ends of the print medium and having a width not exceeding the distance between the side walls outside the pair of side grooves is prepared. . In this way, it is possible to prepare print data that can be printed without margins to the left and right edges of the print medium without causing ink droplets to land on the platen.

  In addition, when ejecting ink droplets to the extended region, it is preferable to do the following. That is, the position of the print medium in the main scanning direction is set so that the print medium is supported by the platen and both side edges of the print medium are kept on the openings of the side grooves. To do. In the main scanning, when the dot forming element is located at a position facing the print medium, the dot forming element is located at a position beyond a side edge of the print medium and faces the side groove. When in position, ink droplets are 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.

  Further, when preparing the print data, it is preferable to prepare the print data having information on the dot recording state in each pixel in the extended area. According to such an aspect, it is possible to easily set a portion of the extended area that extends beyond the edge of the print medium.

  As one aspect of the present invention, there is a dot recording control device that includes an image data generation unit, an area size storage unit, an input 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 area size storage unit stores, for each type of print medium, information on an extended area that is a recording area of an image to be recorded on the print medium and has a length that exceeds at least the upper and lower edges of the print medium. Information on the type of print medium is input from the input unit. The print data generation unit generates print data for recording dots forming an image in the extension region from the information on the type of the print medium input from the input unit, the extension region information, and the image data. .

  According to such an aspect, it is possible to generate print data that can be printed without a margin to the edge of the printing paper without landing ink droplets on the platen. Then, by setting the expansion area to a necessary and sufficient size according to the type of the print medium, ink droplets are ejected to an area that is unnecessarily large with respect to the size of the print medium, and wasted time is used for printing It is possible to generate print data that does not occur.

  The extended area corresponds to the upper end portion of the print medium, which is set in order from the top, exceeding the upper end of the print medium, and the dot formation of the portion is assigned to the dot forming element facing the groove portion, Corresponding to the inner upper end portion assigned to the dot forming element facing the groove portion, the intermediate portion corresponding to the intermediate portion of the print medium, and the lower end portion of the print medium, the dot formation of the portion is the groove portion And the lower end portion assigned to the dot forming element facing the groove and the outer lower end portion set to exceed the lower end of the print medium and assigned to the dot forming element facing the groove portion. It is preferable to do as follows. That is, in the area size storage unit, the size of the outer upper end portion in the sub-scanning direction, the inner upper end portion in the sub-scanning direction size, the inner lower end portion in the sub-scanning direction size, and the outer lower end portion in the sub-scanning direction. Are substantially memorized.

  According to such an aspect, the position of the extended area with respect to the print medium can be appropriately defined, and ink droplets are applied to the outer upper end, the inner upper end, the inner lower end, and the outer lower end of the extended area. By discharging, it is possible to perform printing at the edge of the print medium with no margin to the edge of the printing paper and without causing ink droplets to land on the platen.

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.

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. Explanatory drawing which shows the example of the expansion area | region table EAT. FIG. 3 is an explanatory diagram illustrating a relationship between a printing paper P and an extended region R when the printing paper P is tilted. FIG. 4 is an explanatory diagram illustrating a relationship between a printing paper P and an extended region R when a shift 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 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.

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:
C8. Modification 8:

A. Summary of embodiment:
FIG. 1 is an explanatory diagram showing a relationship between a printing paper and an area for forming an image in the embodiment of the present invention. In the present invention, the region R in which the printer forms an image by ejecting ink droplets based on the image data D is set larger than the printing paper P. The positional relationship between the image recording area R based on the image data and the printing paper P is defined as shown in FIGS. By forming an image in a larger area R that covers the printing paper P with respect to the printing paper P, even if the position of the printing paper P is slightly shifted, the image is printed without margins to the edge of the printing paper P. Can do. The recording area R is indicated by R1 to R6 in each figure, and the printing paper P is indicated by P1 to P6.

  Further, the upper end portion Rf and the lower end portion Rr of the recording area R are recorded only by nozzles located at positions facing the groove portions provided in the platen. For this reason, an error occurs in the sub-scan feed of the printing paper P, or the printing paper P is inclined from an assumed posture, and the ink for recording the edge portion even if the printing paper P does not exist at the planned position. Drops do not stain the platen. The upper end portion Rf of the recording area R is indicated by Rf1 to Rf6 in each drawing, and the lower end portion Rr is indicated by Rr1 to Rr6.

  In the present invention, the image data recording area R is determined according to the type of printing paper P. The printing paper P4 in FIG. 1D is larger than the printing paper P1 in FIG. Accordingly, the image data recording area R4 for recording an image on the printing paper P4 is set larger than the image data recording area R1 for recording an image on the printing paper P1. When the positions of the four edges of the printing paper are shifted in the main scanning direction and the sub-scanning direction due to the inclination of the printing paper P, the larger the length of one side of the printing paper P, the larger the shift amount. If the recording area is defined, it is difficult to create a margin at the edge of the printing paper. Since a small recording area R1 is allocated to the printing paper P1 smaller than the printing paper P4, a wasteful time is required for printing by recording an image in a recording area for unnecessarily large image data. There is no use.

  Further, the printing papers P1, P2, and P3 have the same size, but the materials are different from each other, and the slipperiness of the paper in the sub-scan is larger in the order of P1, P2, and P3. The length of the image recording area R for each print sheet in the sub-scanning direction is longer in the order of R1, R2, and R3. More specifically, the length in the sub-scanning direction of the upper end portion Rf and the lower end portion Rr recorded by the nozzles on the grooves in the recording region R becomes longer in the order of R1, R2, and R3. For this reason, even in a slippery printing paper, even if a relatively large slip occurs during sub-scanning, there is a possibility that a margin will be formed at the end of the printing paper or ink droplets will land on the platen. small. Similarly, the print papers P4, P5, and P6 have the same size, but the slipperiness of the paper in the sub-scan is larger in the order of P4, P5, and P6, and therefore the upper end Rf and the lower end of the recording area R The length of the portion Rr in the sub-scanning direction is longer in the order of R4, R5, and R6.

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 such that the recording area of the image determined from the paper type and the extended area table EAT inputted in advance can be recorded with the designated 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.

  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 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 26b3 correspond to “a pair of side 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.

  In the first embodiment, it is assumed that the dimension in the main scanning direction (left and right direction in FIG. 6) of the portion of the extended region R that is set beyond the left end Pa and the right end Pb of the printing paper P is constant. . Therefore, the width of the printing paper in the main scanning direction is set to Wp (varies depending on the type of paper), the width of the portion of the extended region R set beyond the left end Pa is set to Wa (a constant value), and exceeds the right end Pb. If the width of the portion of the extended region R to be set is Wb (a constant value), the width Wr of the extended region is determined by the formula Wr = Wp + Wa + Wb. The width Wr of the extended region R 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. The right groove defining the width of the extended region R is the right groove 26b in the case of printing paper having the maximum width usable in the printer 22, but the right groove 26b2 in the case of printing paper having a narrower width. Or the right groove 26b3.

  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 only by the nozzle group Nr in the position facing the downstream groove portion 26r in the nozzle row provided in the print head 28. Further, in the extended region R, the portion adjacent to the outer upper end portion Rfp on the inner side from the upper end Pf of the printing paper P is also recorded by only the nozzle group Nr, which is the same as the outer upper end portion 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 an explanatory diagram showing an example of the extended area table EAT. The extended area table EAT (see FIG. 2) includes 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, and the inner lower end Rrq according to the type of printing paper. The length Lrq can be maintained. In FIG. 7, the extended area information 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. The resolution conversion module 97 refers to the extended area table EAT holding information in the form as shown in FIG. 7, and converts the image data into data that can record the extended area at a specified resolution. . At this time, since 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, and the length Lrq of the inner lower end Rrq are determined, the extension region R The layout of the print paper P is 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”. In the first embodiment, 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, and the length Lrq of the inner lower end Rrq are each “mm”. ", But may be stored in the number of rasters. In this case, 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 an integer of ((Lfp / 25.4) / (1/720)). The value can be rounded to the nearest unit.

  FIG. 8 is an explanatory diagram showing the relationship between 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 sizes of the outer upper end Rfp, the inner upper end Rfq, the outer lower end Rrp, and the inner lower end Rrq are determined according to the size of the printing medium. 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. 8, 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, even when the printing paper P 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 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 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 You can avoid wasting time.

  Although the lower end Pr of the printing paper P is illustrated and described here, the relationship between the expansion area R and the inclination of the printing paper P is the same on the upper end Pf side. 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. 9 is an explanatory diagram showing the relationship between the printing paper P and the extended region R when a shift occurs in the sub-scan feed. The solid line indicates the arrangement of the print paper P, and the alternate long and short dash line indicates the position of the print paper P when the sub-scan feed is displaced. 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 sizes of the outer upper end Rfp, the inner upper end Rfq, the outer lower end Rrp, and the inner lower end Rrq are determined according to the material and dimensions of the print medium. 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. Therefore, even when slippage is larger than expected in the sub-scanning and the printing paper P 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 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 print medium that is unlikely to slip during sub-scan feed, wasted time is not used during 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.

B3. Printing process steps:
FIG. 10 is a flowchart showing the user's procedure for the driver after the application program issues a print command. FIG. 11 shows a window for instructing the material of the printing paper. FIG. 12 shows a window for instructing the size 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. 11 is displayed.

  In step S1 of FIG. 10, the user first selects the “basic setting” tab among the plurality of tabs of the window of FIG. 11, and selects the paper type (material) in the “paper type” item. In the window of FIG. 11, “paper type” means “material” of the printing paper in this specification. In FIG. 11, “plain paper” is selected. Thereafter, as shown in FIG. 12, the user selects the “paper setting” tab in step S2, and selects the paper size in the “paper size” item. In FIG. 12, “A4” is selected. Then, the “OK” icon at the bottom of the window in FIG. 12 is clicked, and the “OK” icon in the “Print” window is clicked. The printer driver 96 starts resolution conversion by the resolution conversion module 97, and printing is executed (step S3). Each instruction (selection) to the printer driver by the user as described above is made not only through the mouse 13 but also through the keyboard 14 (see FIG. 2). These mouse 13 and keyboard 14 correspond to an “input unit” in the claims.

B4. Dot formation:
(I) Upper end processing:
FIG. 13 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. 13, 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. 13, 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. 13, 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. 13, 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. 13, 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. In other words, the rasters that can be used for recording an image in this 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. 13, the numbers assigned in order from the top with respect to the raster 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. 13, three nozzles pass through the thirteenth and fifteenth rasters from the top in the main scan 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. 14 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. That is, using FIG. 14, the upper end of the printing paper P will be at a position 6 rasters behind the # 1 nozzle. In FIG. 14, 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. 13) 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. 13, 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. 13) 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 has been fed more than the original feeding amount, as shown by the alternate long and short dash line in FIG. 14, 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. 13, in this embodiment, two rasters are recorded by the # 1 and # 2 nozzles 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. 15 is an explanatory diagram showing how each raster is recorded by which nozzle in the lower end processing. FIG. 15 shows from the time when the (n + 1) th sub-scan feed is performed until the last n + 17th sub-scan feed. In this embodiment, as shown in FIG. 15, in the intermediate process, the feed of 5 dots, 2 dots, 3 dots, and 6 dots is repeated in that order in the sub-scan feed up to the (n + 8) th time. 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. 15, numbers assigned in order from the bottom are shown on the right side of the drawing for rasters on which the nozzles 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. 15, 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. 15, 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. 16 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. 16, the portion of the nozzle group Nf 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. 17 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. 15). ). 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. 15) 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. 9), 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 tilted 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 one-dot chain line in FIG. 8). That is, as indicated by the alternate long and short dash line in FIG. 17, 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. 15) 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. 9), 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. 8). 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. 18 is an explanatory diagram showing printing at 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 side walls on the outside of a pair of side grooves described later. Width. Accordingly, by ejecting ink droplets from the nozzle Nz according to the image data D, the nozzle Nz is located 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 end of the printing paper P and on the left groove 26a, the right groove 26b2, or the right groove 26b3. 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 width Wr of the extended region R is obtained by adding the constant widths Wa and Wb to the width Wp of the print medium regardless of the type of the print medium. However, the width of the extended area portion set beyond the left and right edges of the print medium can also be determined according to the type of print paper. When the printing paper is tilted from the assumed posture, the positional deviation between the left and right edges of the printing paper is proportional to the tilt angle and the dimension in the sub-scanning direction as in the case of FIG. Therefore, if the width of the extended area set beyond the left and right edges of the print medium is determined according to the type of print paper, when the print paper is tilted, there will be margins at the left and right edges. It is possible to further reduce the possibility of ink droplets landing on the platen.

C2. Modification 2:
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 other words, the print medium may be anything as long as it can record an image using a dot forming element.

C3. Modification 3:
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 16). 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 of a printing medium. In other words, a plurality of side grooves provided at intervals substantially equal to the width of the print medium can be provided according to the type of width of the print medium that can be used in the printing apparatus. It can be implemented in various ways.

C4. Modification 4:
In the first embodiment, the upstream groove 26f is provided at a position facing a part of the upstream nozzle group Nf (see FIG. 16) 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. 19 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 modification. 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.

C5. Modification 5:
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.

C6. Modification 6:
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.

C7. Modification 7:
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.

C8. Modification 8:
In the above embodiment, a part of the configuration realized by hardware may be replaced with 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.

12 ... Scanner 13 ... Mouse 14 ... Keyboard 21 ... CRT
22 ... Printer 23 ... Paper feed motor 24 ... Carriage motor 25 ... Lfp /
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, 26o ... platen 26a ... left groove 26b, 26b2, 26b3 ... right side groove part 26c ... central support part 26f ... upstream side groove part 26m ... central groove part 26r ... downstream side groove part 26sf ... upstream side support part 26sr ... downstream side support part 27, 27f, 27r ... absorbing member 28, 28o ... printing 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 ... Black ink cartridge 72 ... Color ink cartridge 90 ... Host computer 91 ... Video driver 95 ... Application program 96 ... Printer driver 97 ... Resolution conversion module 98 ... Color correction module 99 ... Halftone module 100 ... Rasterizer A ... Arrow D ... Image data D ... Recording area DT ... Dot formation pattern table EAT ... Expansion area table Ip ... Ink drop LUT ... Color correction table Nf, Nm, Nr ... Nozzle group Nz ... Inkjet nozzle ORG ... Original color image data P, P1-P6 ... Printing paper PD ... Print data Pa ... Left end Pb ... Right end Pf Lower end R, R1-R6 ... extension area of the upper end Pr ... printing paper of the printing paper (recording area of the image)
R26 ... Range Rf ... Upper end of extended region Rfp ... Outer upper end Rfq ... Inner upper end Rr ... Lower end of extended region Rrp ... Outer lower end Rrp ... Outer upper end Rrq ... Inner lower end d1-d4 ... Deviation amount k ... Nozzle pitch

Claims (2)

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;
A platen that supports the print medium so as to face the dot recording head;
A control unit for controlling the head drive unit and the transport unit;
The platen is
A groove for receiving ink droplets detached from the print medium;
An upstream support portion that is positioned upstream of the groove portion in the conveying direction and is positioned so as to face a part of the dot forming elements among the plurality of dot forming elements ;
The control unit, when ejecting ink droplets to the downstream end in the transport direction of the print medium, the print medium is supported by the platen, and the downstream end is located above the groove, In addition, the dot recording apparatus sets the position of the print medium in the transport direction so that the downstream end in the transport direction is positioned upstream of the dot forming element. 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;
A platen that supports the print medium so as to face the dot recording head;
A control unit for controlling the head drive unit and the transport unit;
The platen is
A groove for receiving ink droplets detached from the print medium;
A downstream support portion positioned downstream of the groove portion in the transport direction and positioned to face some of the plurality of dot formation elements ; and
The control unit, when ejecting ink droplets to an upstream end in the transport direction of the print medium, the print medium is supported by the platen, and the upstream end is located above the groove, In addition, the dot recording apparatus sets the position of the print medium in the transport direction so that the upstream end in the transport direction is positioned downstream of the dot forming element.

Images