JP2006334939A - Liquid delivering head and method for driving liquid delivering head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease generation of unevenness of delivering (white stripe and black stripe) or the like caused by difference in the appropriate amount of delivering for every recording medium. <P>SOLUTION: A liquid delivering head which scans and moves in the scanning direction intersecting the carrying direction of a recording medium, comprises: a plurality of delivering openings for delivering a liquid arranged along the carrying direction of the recording medium; and a delivering direction controlling unit which controls the delivering directions of one or more delivering openings arranged on the end part in the carrying direction among a plurality of the delivering openings in accordance with the kind of the recording medium. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid discharge head having a discharge port for discharging a liquid.

  In recent years, with the spread of digital cameras and the like, there is an increasing demand for higher quality for color printing. In order to obtain a high-definition and high-gradation print image, (1) a method for improving the resolution by narrowing the arrangement interval of the ejection ports for ejecting ink, and (2) the ratio of the colorant, that is, the colorant Preparing a plurality of liquid ejection heads that respectively eject a plurality (at least two) of color inks having different densities, and selectively overprinting these color inks, thereby improving gradation characteristics; (3) There is a known method for improving the gradation by changing the size of the ink droplets ejected from the ejection ports, that is, the ink amount.

  According to the so-called bubble jet (registered trademark) type printer that generates bubbles in the ink and uses the foaming pressure at that time in order to eject ink from the ejection port of the liquid ejection head. The method (3) is currently difficult to apply, and the method (2) is disadvantageous in terms of cost, so the method (1) is preferable.

  When the size of the individual ink droplets discharged from each discharge port is reduced (for example, 10 picoliters or less) by narrowing the arrangement interval of the discharge ports, bubbles that grow due to film boiling with heating of the ink There is known a bubble-through system that communicates with the atmosphere through a discharge port (Patent Documents 1 and 2). This method is distinguished from the conventional bubble jet (registered trademark) method that ejects ink droplets without allowing bubbles that grow due to film boiling to communicate with the atmosphere.

  This bubble-through liquid ejection head is suitable for ejecting small ink droplets because the size of the ink droplet can be determined only by the geometric shape of the ejection port. In addition, this bubble-through type head is less susceptible to temperature and the like, and has the advantage that the amount of ink droplet ejection is very stable compared to the conventional bubble jet (registered trademark) type liquid ejection head. Therefore, it is suitable for forming a print image with high definition and high gradation.

By the way, in a line head that does not require scanning by arranging the discharge ports over one line, the landing positions of the ink discharged from the plurality of discharge ports are the original positions due to manufacturing errors of the discharge ports. It will deviate from. In order to make the deviation of the landing position inconspicuous, a technique for controlling the ink ejection direction by arranging a plurality of heaters at ejection ports has been proposed (Patent Document 3).
Japanese Patent Laid-Open No. 4-10940 JP-A-4-10941 JP 2002-240287 A

  However, in the above-described conventional technology, there are cases in which ejection unevenness such as white stripes or black stripes occurs between a certain scan line and the next scan line.

  FIG. 16 is a diagram illustrating an example of occurrence of white stripes. It can be understood from the figure that white streaks 1503 are generated between the image 1501 formed by the first scan and the image 1502 formed by the next scan. Such white stripes and black stripes are generated when an appropriate feed amount differs for each recording medium.

  Therefore, an object of the present invention is to solve at least one of such problems and other problems. Other issues can be understood throughout the specification.

  The present invention is, for example, a liquid ejection head that scans and moves in a scanning direction that intersects the conveyance direction of a recording medium, and a plurality of liquid ejection heads that are arranged along the conveyance direction of the recording medium. And a discharge direction control unit that controls a discharge direction of one or more discharge ports arranged at an end in the transport direction among the plurality of discharge ports according to the type of the recording medium. It is characterized by.

  According to the present invention, by controlling the ejection direction of one or more ejection ports arranged at the end among the plurality of ejection ports arranged in the conveyance direction of the recording medium, it is possible to obtain an appropriate value for each recording medium. It is possible to suppress the occurrence of discharge unevenness (white stripes or black stripes) caused by different feed amounts.

  In the following, an embodiment useful for understanding the high-level concept, middle-level concept, and low-level concept of the present invention will be described. Note that not all of the concepts included in the following embodiments are described in the claims. However, it should be understood that this is not intentionally excluded from the technical scope of the patented invention, but is not described in the scope of claims because it is equivalent to the patented invention.

<First embodiment>
FIG. 1 is a diagram illustrating an appearance of a mechanism portion of an ink jet printer according to an embodiment. In this embodiment, an inkjet printer is used as an example of an image forming apparatus. However, the present invention can be applied not only to a facsimile machine and a multifunction machine but also to a liquid ejection apparatus that ejects liquid using a liquid ejection head. Absent.

  The chassis 10 of the inkjet printer according to the embodiment is composed of a plurality of plate-like metal members having a predetermined rigidity, and forms the skeleton of the inkjet printer. For the chassis 10, a medium feeding unit 11 that automatically feeds a sheet-like recording medium (not shown) into the ink jet printer and a recording medium fed one by one from the medium feeding unit 11 are desired. A medium transport section 13 that guides the recording medium from the print position to the medium discharge section 12, a print section that performs a predetermined printing operation on the recording medium transported to the print position, and recovery for the print section. A head recovery unit 14 that performs processing is assembled.

  The printing section described above includes a carriage 16 that is supported so as to be able to scan and move along the carriage shaft 15, and a head cartridge 18 (FIG. 3) that is detachably mounted on the carriage 16 via a head set lever 17. ing.

  The carriage 16 on which the head cartridge 18 is mounted has a carriage cover 20 for positioning the liquid discharge head 19 (FIGS. 2 and 3) of the head cartridge 18 at a predetermined mounting position on the carriage 16, a liquid discharge The above-described head set lever 17 is provided that engages with the tank holder 21 (FIGS. 2 and 3) of the head 19 to press the liquid discharge head 19 so as to be positioned at a predetermined mounting position.

  FIG. 2 is a diagram illustrating an appearance of the liquid discharge head according to the embodiment. The tank holder 21 is a means for holding an ink tank 24 described later. One end of a contact flexible printed cable (hereinafter referred to as a contact FPC) 22 (not shown) is connected to the engagement portion of the carriage 16 with the liquid discharge head 19, and a contact (not shown) formed at one end of the contact FPC 22. And the contact part 23 which is an external signal input terminal provided in the liquid discharge head 19 are in electrical contact with each other so as to exchange various information for printing and supply power to the liquid discharge head 19. It has become. The upper plate member 32 is provided with a plurality of liquid discharge ports 25.

  FIG. 3 is a diagram illustrating an appearance of the ink cartridge according to the embodiment. The head cartridge 18 according to this embodiment includes the above-described liquid discharge head 19 that discharges ink supplied from the ink tank 24 from the discharge port of the liquid discharge head 19 according to print information. And have. The liquid discharge head 19 of this embodiment employs a so-called cartridge system that is detachably mounted on the carriage 16.

  Further, in the present embodiment, in order to enable high-quality color printing with photographic tone, for example, six ink tanks 24 in which black, light cyan, light magenta, cyan, magenta and yellow inks are independent. Can be used. Each ink tank 24 is provided with an elastically deformable detachable lever 26 that can be locked with respect to the head card ridge 18, and by operating the detachable lever 25, as shown in FIG. Each of the heads 19 is removable. Therefore, the detaching lever 26 functions as a part of the attaching / detaching means of the present invention.

  FIG. 4 is a diagram illustrating an appearance of a print element substrate of the liquid ejection head according to the embodiment. FIG. 5 is a cross-sectional view of the vicinity of the discharge port according to the embodiment. Specifically, FIG. 5 is a cross-sectional view taken along the line A-A ′ shown in FIG. 4.

  The liquid discharge head 19 is composed of the print element substrate 27 and the tank holder 21 described above. For example, the print element substrate 27 in the present embodiment has a heater, a common ink chamber 31, an ink path 33, an ejection port 25, and the like formed on a silicon substrate having a thickness of 0.5 mm to 1 mm by using a film forming technique. Is. The print element substrate 27 is formed with an elongated ink supply port 28 penetrating therethrough. On both sides of the ink supply port 28, a plurality of heaters 29 (in this embodiment, 256 on one side) are arranged in two rows at a predetermined interval along the conveyance direction of the recording medium, that is, the longitudinal direction of the ink supply port 28. Are formed so as to be shifted from each other by a half pitch (see FIG. 6). The center-to-center distance of each row is, for example, 233 μm, and each constitutes a heater. In addition to these heaters 29, electrode terminals 30 for electrical connection between the heaters 29 and the printer main body and electrical wiring (not shown) formed of aluminum or the like are formed on the print element substrate 27 by a film forming technique. ing.

  The electric wiring board connected to the electrode terminal 30 formed on the print element substrate 27 is for applying an electric signal for ejecting ink to the print element board 27. This electrical wiring board has electrical wiring corresponding to the printed element board 27 and the above-described contact part 23 which is located at an end of the electrical wiring and receives an electrical signal from the printer main body. The contact portion 23 is positioned and fixed on the back side of the tank holder 21. A drive signal for the heater 29 is given from the drive signal output unit (FIG. 8) via the electric wiring board, and at the same time, drive power is supplied to the heater 29.

  An ink flow path extending from the ink tank 24 to the ink supply port 28 of the print element substrate 27 is formed in the tank holder 21 that detachably holds the ink tank 24.

  As can be seen from FIG. 5, an upper plate member 32 having a plurality of ejection ports 25 respectively facing the heater 29 is formed on the print element substrate 27 via a common ink chamber 31 communicating with the ink supply port 28. . That is, an ink path 33 that communicates with each ejection port 25 and the common ink chamber 31 is formed between the upper plate member 32 and the print element substrate 27, and a partition wall is formed between the adjacent ink paths 33. 34 is formed. The common ink chamber 31, the ink path 33, the partition wall 34, and the like are formed together with the upper plate member 32 by photolithography technology in the same manner as the ejection port 25.

  The liquid supplied from the ink supply port 28 into each ink path 33 is boiled as the heater 29 generates heat when a drive signal is given to the heater 29 facing the corresponding ink path 33, and bubbles are generated thereby. It is discharged from the discharge port 25 by the pressure of. In this case, bubbles generated in the liquid chamber 31 are brought into an air communication state from the discharge port 25 as they grow.

  The ink-jet liquid discharge head 19 is scanned along the recording medium at a high speed along with the carriage 16 and ink droplets are continuously discharged from all the discharge ports 25 to perform so-called image printing on the recording medium. In the case of the conventional liquid discharge head that does not control the discharge direction, it has been found that white stripes 7 as shown in FIG. 16 occur.

  This is because an image is formed with an inappropriate paper feed amount even though an appropriate paper feed amount exists for each material of the recording medium. In particular, white streaks occur when the feed amount exceeds the print width. On the other hand, black streaks occur when the feed amount is less than the print width. Further, when performing photographic tone printing, a multi-pass method in which an image is formed by a plurality of passes is used, but in this case, unevenness occurs at the connecting portion of the passes.

  By the way, the inventors set a paper feed amount suitable for the CANON PR-101 paper as a reference value and printed on the CANON SP paper using the conventional technique. According to the result of this experiment, it was found that a deviation of about 5 μm was generated per scan, and that a streak of about 10 to 20 μm was generated in 4-pass printing. It has also been found that the width of the stripe increases as the recording medium feed amount increases. For example, when the number of passes is reduced and the paper feed amount per scan is increased in order to increase the printing speed, the paper feed amount is shifted and a wide stripe is generated. As described above, the width of the stripe changes depending on the paper feed amount per scan.

  FIG. 6 is a diagram illustrating an example of the arrangement of the discharge ports according to the embodiment. In the arrangement of the discharge ports shown in FIG. 6, the interval between the discharge ports 25 is set to 600 dpi (42.3 μm). In addition, a plurality of heaters (heaters 29a and 29b) are provided in the discharge ports 25 and the like located near the end in the transport direction among the discharge ports 25 in the discharge port array. In this example, up to twenty discharge ports 25 counted from both ends in the arrangement direction are discharge ports near the ends. The other discharge ports 25 serve as discharge ports in the center portion. As described above, when one row is formed by 256 discharge ports, 256-20 * 2 = 216 discharge ports are provided in the central portion. Further, since 20/256 = about 0.08, 8% from the end of the discharge port row is the discharge port near the end.

  According to FIG. 6, the left ejection port array and the left ejection port array are arranged with a shift of ½ with respect to the arrangement interval of the ejection ports. Thereby, the arrangement density of the discharge ports 25 in two rows is approximately 1200 dpi.

  In the present embodiment, the heater 29 provided in the central discharge port is a square having a side of 24 μm. Further, the heaters 29a and 29b provided at the discharge ports near the ends are each 12.5 μm × 28 μm rectangles. The discharge port 25 has a circular shape with a diameter of 14 μm. About 4 picoliters (pl) of ink droplets are ejected from the ejection port 25. The ink droplet ejection speed is, for example, 10 to 15 m / s.

  The shape of the discharge port 25 may be set to a shape such as a rectangle or a star as well as a circle.

  Thus, in this embodiment, about 4 pl is discharged from the discharge port array in the array state shown in FIG. In addition, two heaters 29a and 29b are arranged in a total of 40 discharge ports 25 located near both ends in the arrangement direction.

  FIG. 7 is a diagram illustrating an example of driving timings of a plurality of heaters according to the embodiment. FIG. 8 is a diagram illustrating a control example of the ejection direction according to the embodiment. When there is no deviation between the paper feed amount of the recording medium actually used and the paper feed amount set in the image forming apparatus according to the present embodiment, the heaters 29a and 29b as shown in FIG. Are driven simultaneously.

  At the drive timing shown in FIG. 7A, the liquid is ejected in the direction a (ie, straight) in FIG. When the paper feed amount is larger than the reference value, the liquid is ejected in the direction b shown in FIG. 8 by shifting the drive timing as shown in FIG. 7B. As a result, the print width is temporarily enlarged, and white stripes can be reduced.

  On the other hand, when the paper feed amount is smaller than the reference value, the liquid is ejected in the direction c shown in FIG. 8 by shifting the drive timing as shown in FIG. As a result, the print width is narrowed, so that black stripes can be reduced.

  FIG. 9 is an exemplary block diagram of the ink jet printer according to the embodiment. The CPU 901 is a control unit for comprehensively controlling the ink jet printer. The ROM 902 is a storage unit that stores a control program and the like. The RAM 903 is a storage unit that temporarily stores control data and the like. The communication unit 904 is a communication circuit for communicating with an external information processing apparatus such as a PC or a digital camera. The drive signal output unit 905 is a circuit that outputs a drive signal for controlling the discharge timing and the discharge direction of the liquid discharged from the discharge port 25. This drive signal is supplied to the heater 29 (29a, 29b) of the liquid discharge head. The display unit 906 is a display circuit such as a liquid crystal display device. The input unit 907 is an input device for inputting operation input from the user.

  FIG. 10 is an exemplary flowchart regarding a liquid discharge process of the ink jet printer according to the embodiment. It is assumed that the control program related to this flowchart is stored in the ROM 902 described above.

  In step S <b> 1001, the CPU 901 accepts a print instruction input from the input unit 907. In step S <b> 1002, the CPU 901 displays properties for performing settings related to printing on the display unit 906. In step S <b> 1003, the CPU 901 selects a print mode and a recording medium according to an operation input from the input unit 907. As a result, the type of recording medium used can be determined. In step S1004, the CPU 901 determines the drive time offset amount t according to the selected recording medium. For example, by storing the offset amount for each recording medium in the ROM 902 as a table, the CPU 901 may read the offset amount corresponding to the selected recording medium from the table. In step S1004, the CPU 901 causes the drive output unit 905 to output drive signals to the heaters 29, 29a, and 29b according to the offset amount. Thus, the printing process is executed.

  In the above-described embodiment, the ejection direction is controlled according to the recording medium in the image forming apparatus such as an ink jet printer. However, it goes without saying that the ejection direction may be controlled in the information processing apparatus connected to the image forming apparatus.

  FIG. 11 is an exemplary block diagram of the information processing apparatus according to the embodiment. The CPU 1101 is a control unit for comprehensively controlling the information processing apparatus. A ROM 1102 is a storage unit that stores a printer driver, various control programs, and the like. The printer driver or the like may be stored in a hard disk drive device (not shown). The RAM 1103 is a storage unit that temporarily stores control data and the like. The communication unit 1104 is a communication circuit for communicating with the image forming apparatus. The display unit 1106 is a display circuit such as a liquid crystal display device. The input unit 1107 is an input device for inputting operation input from the user.

  FIG. 12 is an exemplary flowchart regarding the printer driver according to the embodiment. In step S1201, the CPU 1101 receives a print instruction input from the input unit 1107, and displays a print dialog for performing settings related to printing on the display unit 1106. In step S <b> 1202, the CPU 1101 receives an instruction to select a property button included in the print dialog from the input unit 1107. In step S1203, the CPU 1101 selects a print mode and a recording medium according to an operation input from the input unit 1107. As a result, the type and feed amount of the recording medium used can be determined. In step S1204, the CPU 1101 determines a driving time offset amount t in accordance with the selected recording medium. For example, by storing the offset amount for each recording medium in the ROM 1102 as a table, the CPU 901 may read the offset amount corresponding to the selected recording medium from the table. In step S1204, the CPU 1101 transmits a print control signal including an offset amount to the image forming apparatus.

  In step S1206, the CPU 901 of the image forming apparatus receives a print control signal from the information processing apparatus. In step S1207, the CPU 901 causes the drive output unit 905 to output a drive signal to each of the heaters 29, 29a, and 29b according to the offset amount. Thus, the printing process is executed.

  As described above, according to the present embodiment, for example, the ejection direction of one or more ejection ports arranged near the end is controlled in accordance with the feed amount depending on the type of the recording medium. Uneven discharge such as white stripes and black stripes can be reduced. That is, it is possible to reduce discharge unevenness by dynamically changing the print width according to the type of the recording medium.

  Further, according to the present embodiment, a plurality of heaters 29a and 29b are provided for each of one or more discharge ports arranged near the end in the transport direction, and the discharge direction is set by offsetting these drive signals. Can be controlled. Therefore, the discharge direction can be controlled with a relatively simple configuration, and discharge unevenness can be reduced.

<Second Embodiment>
In the first embodiment described above, a plurality of heaters having substantially the same area are arranged with respect to the discharge ports located in the vicinity of the end in the arrangement direction of the discharge ports, and the respective drive timings are offset.

  In the second embodiment, the discharge direction is controlled by making the heat generation amounts (bubble generation capability) of the plurality of heaters different. Hereinafter, as an example, an example in which the sizes (surface areas) of the plurality of heaters are made different will be described. Needless to say, other methods may be employed, such as making the materials of the plurality of heaters different, as long as the amount of heat generated can be made different. In addition, the same reference numerals are assigned to the parts that have already been described, and efforts are made to avoid duplication of explanation.

  FIG. 13 is a diagram illustrating an example of the arrangement of the discharge ports according to the embodiment. According to FIG. 13, one heater 29 is disposed in the discharge port 25 located in the center portion of the discharge ports in the arrangement direction, but the discharge port 25 located in the vicinity of both ends in the arrangement direction has a size. A plurality of different heaters 29c and 29d are arranged. As described above, by arranging the plurality of heaters 29c and 29d having different calorific values at the outlet 25 in the vicinity of the end portion, the liquid discharge direction can be suitably controlled.

  In addition, about the drive timing of several heater 29c, 29d, it is good also as the same drive timing. That is, since the surface areas of the inner heater 29c and the outer heater 29d are different, the discharge direction is outside the normal direction. The inner side means the direction of the central part when viewed from the end part, and the outer side means the direction of the end part from the central part.

  Furthermore, if the drive timings of the plurality of heaters 29c and 29d are offset as described above, it will be possible to control the ejection direction further greatly.

<Third embodiment>
In the above-described embodiment, it has been described that the volume of the liquid ejected from the ejection port 25 at a time is substantially the same, but it is not necessarily the same. Therefore, in the third embodiment, a liquid ejection head in which the volume of liquid droplets ejected from the first row of ejection ports and the volume of liquid droplets ejected from the second row of ejection ports will be described. . That is, in the liquid discharge head according to the present embodiment, at least two types of discharge port arrays having different droplet volumes are mixed.

  FIG. 14 is a diagram illustrating an example of the arrangement of the discharge ports according to the embodiment. According to FIG. 14, the liquid discharge head is configured so that two types of discharge port arrays such as array (a) and array (b) are mixed.

  Each array is a set of two ejection port arrays. In the array (a), the discharge ports 25 included in one of the discharge port arrays are arranged at intervals of 600 dpi (42.3 μm). As can be seen from the figure, the other discharge port array is arranged with a displacement of 1/2 of the discharge port arrangement interval with respect to the one discharge port array. Therefore, the arrangement density of the discharge ports 25 in two rows is approximately 1200 dpi.

  In the array (b), the interval d0 between the ejection ports 125 included in one ejection port array is also set to 600 dpi (42.3 μm). The other discharge port array is shifted from the one discharge port array by d0 / 2. Accordingly, the arrangement density of the discharge ports 125 in two rows is approximately 1200 dpi.

  In this embodiment, the heater 29 in the array (a) is a square having a side of 24 μm, and the heaters 29a and 29b are a rectangle of 12 μm × 28 μm. The ejection port 25 has a circular shape with a diameter of 14 μm, and about 4 picoliters (pl) of ink droplets are ejected from the ejection port 25. The heater 129 in the array (b) is a square having a side of 22 μm, and the heaters 129a and 129b are a rectangle of 11 μm × 27 μm. The ejection port 125 is a circle having a diameter of 12 μm, and about 2 picoliters (pl) of ink droplets are ejected from the ejection port 125. The shape of the discharge ports 25 and 125 is not necessarily circular, and may be set to a shape such as a rectangle or a star.

  In both arrangements (a) and (b), a plurality of heaters are provided at the discharge ports near the ends, and a single heater is provided at the discharge ports near the center. Needless to say, the discharge timing to each heater can be applied as described above.

  As described above, in the present embodiment, even when rows of ejection ports having different volumes of ejected droplets are mixed, the image quality can be further improved by suitably controlling the ejection direction.

  In addition, in FIG. 14, although the shape of the some heater arrange | positioned with respect to the discharge outlet near an edge part is made the same, it is good also as a different size as mentioned above.

<Fourth embodiment>
In the present embodiment, an example will be described in which the above-described discharge unevenness reduction technique is applied to a liquid discharge head in which at least two or more discharge ports with different volume of discharged droplets are alternately arranged.

  FIG. 15 is a diagram illustrating an example of the arrangement of the discharge ports according to the embodiment. According to FIG. 15, the relatively large discharge ports 25 and the relatively small discharge ports 125 are alternately arranged at intervals of 600 dpi (42.3 μm). The other discharge port array is an array obtained by inverting one discharge port array. That is, the discharge port 25 and the discharge port 125 having different sizes are arranged so as to face each other.

  In the present embodiment, the discharge port 25 is circular with a diameter of 14 μm. The heater 29 is a square having a side of 24 μm. The heaters 29a and 29b have a rectangular shape of 12 μm × 28 μm. About 4 picoliters (pl) of ink droplets are ejected from the ejection port 25. On the other hand, the discharge port 125 is circular with a diameter of 12 μm. The heater 129 is a square having a side of 22 μm. The heaters 129a and 129b are 11 μm × 27 μm rectangles. About 2 picoliters (pl) of ink droplets are ejected from the ejection port 125.

  The shapes of the discharge ports 25 and 125 do not have to be circular, and may be set to a shape such as a rectangle or a star.

  The present invention can also be suitably applied to a liquid discharge head in which discharge ports are arranged in this way. That is, one heater 29 is arranged at the discharge port 25 and the discharge port 125 located in the central part in the arrangement direction, and the heater 29a is arranged at the discharge port 25 (discharge port 125) located near the end in the arrangement direction. 29b (129a, 129b). Then, by applying the drive timing as described above, the print width is corrected so as to reduce the discharge unevenness.

  In the present embodiment, by forming pixels using large droplets, it is possible to obtain a print image at a high speed while suppressing recording density, while on the other hand, by forming pixels using small droplets, It is also possible to increase the recording density and obtain a high-definition and high-gradation high-quality print image. In addition, by appropriately controlling the ejection direction as described above, it is possible to reduce ejection irregularities such as white stripes and black stripes that can occur between print lines.

  In FIG. 15, the heaters 29a and 29b have the same size, but may be different as described above. The same applies to the sizes of the heaters 129a and 129b.

  To summarize the above embodiments, the present invention uses, for example, a liquid ejection head having a plurality of ejection openings for ejecting liquid, and the liquid ejection head is in a scanning direction that intersects the conveyance direction of the recording medium. In particular, the present invention relates to an image forming apparatus that forms an image on a recording medium by repeating a recording scan that performs recording by scanning and a conveying operation along the conveying direction of the recording medium, and a related technique.

  In particular, it is preferable to drive the liquid discharge head used in such an image forming apparatus as follows. The direction in which the liquid is ejected is controlled according to the type of the recording medium for at least one ejection port arranged at the end in the transport direction among the plurality of ejection ports. As a result, it is possible to suppress the occurrence of discharge unevenness (white stripes or black stripes) caused by the difference in the appropriate feed amount for each recording medium.

It is a figure which shows the external appearance of the mechanism part of the inkjet printer which concerns on embodiment. It is a figure which shows the external appearance of the liquid discharge head which concerns on embodiment. It is a figure which shows the external appearance of the ink cartridge which concerns on embodiment. It is a figure which shows the external appearance of the printing element board | substrate of the liquid discharge head which concerns on embodiment. It is sectional drawing of the discharge outlet vicinity which concerns on embodiment. It is a figure which shows the example of an arrangement | sequence of the discharge outlet which concerns on embodiment. It is a figure which shows the example of a drive timing of the some heater which concerns on embodiment. It is a figure which shows the example of control of the discharge direction which concerns on embodiment. 1 is an exemplary block diagram of an ink jet printer according to an embodiment. 6 is an exemplary flowchart regarding a liquid discharge process of the inkjet printer according to the embodiment. It is an exemplary block diagram of the information processing apparatus according to the embodiment. 4 is an exemplary flowchart regarding a printer driver according to the embodiment. It is a figure which shows the example of an arrangement | sequence of the discharge outlet which concerns on embodiment. It is a figure which shows the example of an arrangement | sequence of the discharge outlet which concerns on embodiment. It is a figure which shows the example of an arrangement | sequence of the discharge outlet which concerns on embodiment. It is a figure which shows the example of generation | occurrence | production of a white stripe.

Explanation of symbols

25 Ejection port 29, 29a, 29b Heater 31 Common ink chamber 33 Ink path 34 Partition wall

Claims (12)

A liquid ejection head that scans and moves in a scanning direction that intersects a conveyance direction of a recording medium,
A plurality of ejection openings arranged along the transport direction of the recording medium for ejecting liquid;
And a discharge direction control unit that controls a discharge direction of one or more discharge ports arranged at an end portion in the transport direction among the plurality of discharge ports according to the type of the recording medium. Liquid discharge head.   The liquid discharge head according to claim 1, wherein the discharge direction is controlled so as to reduce discharge unevenness caused by a difference in feed amount for each recording medium. The discharge direction control unit includes:
The liquid discharge head according to claim 2, further comprising a plurality of heaters provided for each of the one or more discharge ports arranged at an end in the transport direction.   The liquid discharge head according to claim 3, wherein the discharge direction of the discharge port is controlled by giving a predetermined offset amount between drive timings of the plurality of heaters.   The liquid ejection head according to claim 4, wherein the offset amount is changed according to a type of the recording medium.   The liquid discharge head according to claim 3, wherein the discharge direction of the discharge port is controlled by making the heat generation amounts of the plurality of heaters different from each other.   The liquid discharge head according to claim 6, wherein the heat generation amounts are made different by making the surface areas of the plurality of heaters different from each other.   The liquid discharge head according to claim 6, wherein the difference in the heat generation amount is changed according to a type of the recording medium. A holding unit for holding a tank for storing liquid;
A head cartridge including the liquid discharge head according to claim 1, which discharges the liquid held in the tank. An image forming apparatus that forms an image on a recording medium by discharging a liquid,
A liquid discharge head according to any one of claims 1 to 8,
An image forming apparatus comprising: a drive signal output unit that outputs a drive signal for determining a discharge direction of one or more of the discharge ports included in the liquid discharge head to the liquid discharge head. An information processing apparatus connected to the image forming apparatus according to claim 10,
A discrimination unit for discriminating the type of the recording medium;
An information processing apparatus comprising: a transmission unit that transmits control information for controlling a discharge direction of the discharge port to the image forming apparatus according to the determined type of the recording medium. A recording scan that uses a liquid discharge head having a plurality of discharge ports for discharging liquid, scans the liquid discharge head in a scanning direction that intersects the conveyance direction of the recording medium, and performs recording. A method of driving the liquid ejection head of an image forming apparatus that forms an image on a recording medium by repeating a transport operation along a transport direction,
A liquid ejection characterized by controlling a liquid ejection direction in accordance with the type of the recording medium for at least one ejection port arranged at an end portion in the transport direction among the plurality of ejection ports. Head drive method.

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