JP2006305798A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a waste printing medium when a test pattern for detecting a defective dot or adjusting an ejection timing is printed. <P>SOLUTION: Each of the test patterns is read according to whether a dot omission detection command or an ejection timing adjustment command is issued, and then a non-print region having a size necessary for printing each of the test patterns on a recorded printing medium is detected by using, for example, a scanner. When a non-print region having the necessary size is detected, the non-print region is set to be a position for printing of the test pattern, and then the printing of the test pattern is carried out. When the non-print region is designated by a user, the test pattern is printed in the designated non-print region. When a printing medium is a new one on which the recording is not carried out, the test pattern is printed on a predetermined position. When the test pattern is printed, the printed date and time are printed at the same time so that it is possible to judge when the printing is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet printer that prints predetermined characters and images by ejecting fine particles (ink droplets) of a plurality of liquid inks from nozzles and forming minute dots on a print medium, for example. is there.

Such an inkjet printer is generally inexpensive and can easily obtain a high-quality color printed matter. Accordingly, along with the widespread use of personal computers and digital cameras, it has become widespread not only in offices but also in general users.
In general, such an ink jet printer reciprocates in a direction intersecting with the conveyance direction of a print medium by a moving body called a carriage integrally provided with an ink cartridge and an ink discharge head (generally called an ink jet head). On the other hand, by ejecting fine particles of liquid ink from the nozzles of the ink jet head, predetermined characters and images are drawn on the print medium to create a desired printed matter. The carriage is equipped with ink cartridges of four colors (black, yellow, magenta, cyan) and inkjet heads for each color, so that not only monochrome printing but also full color printing combining the colors can be easily performed. (Furthermore, 6 colors, 7 colors, or 8 colors in which light cyan, light magenta, etc. are added to these colors are also put into practical use).

  By the way, in this type of ink jet printer, bubbles are generated in the cavity (pressure chamber) of the ink jet head, floating paper powder or dust adheres to the vicinity of the nozzle, or the nozzle (inner ink) dries. Then, ink droplets are not ejected from the nozzles, and dots may not be formed on the print medium. Ink droplet ejection failure is generally called “dot missing”. When a dot missing phenomenon occurs, recovery is performed by a cleaning device. For example, when a dot drop phenomenon occurs due to the generation of bubbles, the ink in the nozzle is sucked with a pump to discharge the bubbles inside the cavity, and then the ink attached to the nozzle surface is removed with a wiping member called a wiper. Wiping off and discharging the ink droplets, called flushing, without printing, discharges the mixed ink. This series of cleaning steps recovers the dot drop phenomenon due to bubbles.

However, if ink is sucked from a nozzle in which dot missing has not occurred, the ink is wasted. Therefore, as described in Patent Document 1 below, the present applicant prints a predetermined test pattern on a print medium in order to test the ink droplet ejection state from the inkjet nozzle, and the dot missing from the test pattern is detected. An ink jet printer that can reduce ink waste by detecting the nozzles that are generated and performing ink suction only from the nozzles where the missing dots are generated or only a small number of nozzles including the nozzles. Proposed.
JP 2000-225715 A

  By the way, the test pattern described in Patent Document 1 does not necessarily require a large print area. The print area is, for example, about 30 mm × 25.4 mm for each color in a multi-pass type ink jet printer having 180 nozzles for each color ink. In addition, in the case of a multi-pass type ink jet printer that ejects ink droplets in the forward path and the backward path in the main scanning direction of the carriage, there is also a test pattern for detecting the ink droplet ejection timing in the forward path and the backward path. This area is not that big. Therefore, it is desirable to reduce the waste of the print medium by printing a test pattern on the non-printing area of the recorded print medium or repeatedly printing the test pattern on a single-sheet print medium. Since the test pattern can be printed only in a predetermined area of the print medium, the recorded print medium cannot be used for the test pattern print, and the one-leaf print medium cannot be used repeatedly for the test pattern print. It's wasted.

  The present invention has been made paying attention to the above-described problems. By using a recorded print medium for test pattern printing, or using a single print medium repeatedly for test pattern printing. An object of the present invention is to provide an ink jet printer that can reduce wasteful consumption of a print medium.

  [Invention 1] In order to solve the above-described problems, an inkjet printer according to Invention 1 is an inkjet printer that prints a predetermined test pattern on a print medium in order to test the ejection state of ink droplets ejected from inkjet nozzles. A non-printing area detecting unit for detecting a non-printing area necessary for the test pattern printing on a printing medium; and a test pattern printing unit for printing the test pattern on the non-printing area detected by the non-printing area detecting unit; It is characterized by comprising.

  The ink jet nozzle referred to in the present invention refers to an ink discharge nozzle used in, for example, an ink jet printer, and discharges fine ink droplets onto a print medium by a known electrostatic method, piezo method, film boiling ink jet method, or the like. It is treated as a generic term for those that form round ink dots. The test pattern may be any test pattern as long as it tests the ink droplet ejection state, such as dot missing detection and ink ejection timing.

  According to the ink jet printer of the first aspect of the present invention, the non-printing area necessary for test pattern printing is detected on the print medium, and the test pattern is printed on the detected non-printing area. Can be used for test pattern printing, or a single print medium can be used repeatedly for test pattern printing, and wasteful consumption of the print medium can be reduced.

[Invention 2] The inkjet printer of Invention 2 is characterized in that, in the inkjet printer of Invention 1, the test pattern printing means prints the test pattern printing date and time together with the test pattern.
According to the inkjet printer of the second aspect, by printing the test pattern printing date and time together with the test pattern, it is possible to determine which test pattern is printed when the test pattern is repeatedly printed on a single print medium. Accurately grasp.

[Invention 3] The ink jet printer of invention 3 is the ink jet printer of invention 1 or 2, wherein when the test pattern printing means designates a test pattern printing area, the test pattern printing means applies the test to the designated printing area. A pattern is printed.
According to the ink jet printer according to the third aspect of the present invention, when the test pattern print area is designated, the test pattern is printed on the designated print area, for example, the trouble of scanning the non-print area by the scan function. The test pattern can be printed quickly.

[Invention 4] The inkjet printer of Invention 4 is characterized in that, in the inkjet printer of any one of Inventions 1 to 3, the non-printing area detection means has a scanner function.
More specifically, a so-called multi-function machine having a scanner function and a copier function in addition to the ink jet printer function is compatible.
According to the ink jet printer of the fourth aspect of the present invention, the non-printing area for test pattern printing can be automatically detected by having the scanner function.

Next, a first embodiment of the inkjet printer of the present invention will be described with reference to the drawings.
FIG. 1 shows an inkjet printer 2 of this embodiment and a host computer 1 for driving the inkjet printer 2. The host computer 1 can be any computer system including a personal computer. A device driver 30 for driving itself is built in the inkjet printer 2, and the device driver 30 is appropriately driven by application software to drive the inkjet printer 2, that is, perform printing.

  FIG. 2 shows a schematic configuration of the ink jet printer 2. The ink jet printer 2 according to the present embodiment reciprocates a carriage 21 in which an ink cartridge and an ink jet head are integrally provided in the width direction of the print medium 22 and in the horizontal direction of the drawing, and the print medium 22 is moved in the longitudinal direction. By discharging fine particles (ink droplets) of liquid ink from the nozzles of the inkjet head while feeding the paper in the direction perpendicular to the paper surface, fine ink dots are formed on the print medium 22, whereby predetermined characters are printed on the print medium 22. Or a so-called multi-pass inkjet printer that draws an image and creates a desired printed matter. The reciprocating direction of the carriage 21 is also referred to as a main scanning direction, and the paper feeding direction of the printing medium 22 is also referred to as a sub-scanning direction.

  Reference numeral 13 in FIG. 2 denotes a carriage motor as an actuator for reciprocating the carriage 21 in the main scanning direction, reference numeral 23 denotes a driving pulley for transmitting the driving force of the carriage motor 13, and reference numeral 24 denotes a print medium 22. The reference numeral 25 is a driven pulley disposed on the opposite side of the drive pulley 23, and is a transport belt wound around the drive pulley 23 and the driven pulley 24 and connected to the carriage 21. Reference numeral 3 is a cap for cleaning the nozzles of the ink jet head mounted on the carriage 21, reference numeral 30 is a wiper that strokes the nozzle surface 4 to adjust the meniscus of the nozzles, and reference numeral 7 is a purpose other than printing. In the so-called flushing, in which ink droplets are ejected from the nozzles of the ink jet head, an ink absorber that absorbs the ejected ink droplets, reference numeral 8 is a cleaning device equipped with a suction pump, which will be described later. The ink absorber 7 is preferably made of a porous material that is easy to absorb ink solvent and easily absorbs ink. For example, in the case of water-based ink, a polyvinyl alcohol-based material is used.

Reference numeral 11 denotes a scanner disposed in the paper feeding unit of the print medium 22, and reference numeral 12 denotes a scanner motor for causing the scanner 11 to scan. The ink jet printer according to the present embodiment has a scanner function, and can scan an object set on a paper feeding unit, like a normal scanner.
Reference numeral 31 denotes a control unit, and reference numeral 30 denotes a device driver. The carriage 21 is reciprocated in the main scanning direction by acceleration / constant speed / deceleration / reversal / acceleration / constant speed / deceleration / reversal by the control unit 31 controlling the rotation state of the carriage motor 13. By controlling the print actuator, ink dots are formed on the print medium 22 when the carriage 21 is moving at a constant speed. Further, at every predetermined time, when the power is turned on, or when the power is turned off, the control unit 31 moves the cap 3 up and down and further drives the cleaning device 8 to clean the inkjet head. The control unit 31 drives the scanner motor 12 to scan the scanner 11, and the content detected by the scanner 11 is read by the control unit 31. The conveyor belt 25 is provided with a linear scale, and the position of the conveyor belt 25, that is, the position of the carriage 21 is tracked by reading the linear scale with an encoder.

  For example, as shown in FIG. 3, the inkjet head 34 has a nozzle 5 that ejects black (K) ink exclusively, a nozzle 5 that ejects yellow (Y) ink exclusively, and a magenta (M) ink exclusively. The nozzles 5 to be ejected and the nozzles 5 to be exclusively ejected with cyan (C) ink are arranged in the sub-scanning direction, and liquid ink is ejected from each nozzle 5 of the inkjet head 34 in accordance with a command signal from the device driver. For example, color image data can be printed on the print medium 22 by moving the carriage 21 in the main scanning direction and moving the print medium 22 in the sub-scanning direction (paper feeding direction). In this embodiment, 180 nozzles per inch are provided for each color.

  As a method for ejecting ink from each nozzle of the ink jet head, there are an electrostatic method, a piezo method, a film boiling ink jet method, and the like. In the electrostatic method, when a drive signal is given to the electrostatic gap, which is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and the ink droplet is ejected from the nozzle by the pressure change. is there. In the piezo method, when a drive signal is given to a piezo element that is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and an ink droplet is ejected from the nozzle by the pressure change. In the film boiling ink jet method, there is a micro heater in the cavity, the ink is instantaneously heated to 300 ° C. or more, the ink becomes a film boiling state, bubbles are generated, and the ink droplet is ejected from the nozzle by the pressure change. Is. Any ink discharge method can be applied to the present invention.

  Returning to FIG. 1, the device driver 30 is configured by software. In order to operate the device driver 30, a computer system as an arithmetic processing unit is built in the control unit 31 of the inkjet printer 2. Therefore, the control unit 31 includes a CPU 32 that is a central processing unit that performs various types of control and arithmetic processing, and a memory 33 such as a RAM that constitutes a main storage device and a ROM that is a read-only storage device. The device driver 30 includes an inkjet head driver 35 that drives an inkjet head 34 mounted on the carriage 21, a carriage driver 36 that drives the carriage motor 13 in the main scanning direction of the carriage 21, and a linear scale detected by the encoder 28. A carriage position detection circuit 37 that detects the position of the carriage 21 from the values, a paper feed driver 39 that drives a paper feed motor 38 in the sub-scanning direction of the print medium 22, and a cleaning motor 40 that is used to raise and lower the cap 3. A cleaning driver 41 that drives the suction pump, a suction pump driver 46 that drives the suction pump 10 for sucking ink by drawing a negative pressure in the cap 3, a scanner motor driver 47 that drives the scanner motor 12, and a scanner 11 that drives and detects Was Configured with a scanner driver 48 to Dari crowded read the broadcast. The control unit 31 is connected to the host computer 1 via the interface 42, and performs printing according to the operation state of the operation panel 43 and instructions of application software that is processed by the host computer 1. Various information associated with printing and cleaning is displayed on the display panel 44. The application software for driving the device driver may be executed in a printer control unit provided in the ink jet printer, or may be executed in a completely separate computer system. . Further, functions equivalent to device drivers and application software may be configured by hardware.

   Next, a description will be given of a test pattern for detecting the aforementioned dot dropout and adjusting the ink droplet ejection timing in this ink jet printer. FIG. 4A shows a test pattern for detecting missing dots. In the figure, the nozzles surrounded by circles cause missing dots. In this embodiment, 180 nozzles per inch are provided for each color. For example, about 3 mm of ink droplets are ejected continuously for every 10 nozzles. Similarly, ink droplets are continuously ejected from the nozzles by about 3 mm, and this is repeated 10 times to eject ink droplets from all 180 nozzles. In this example, the 114th nozzle is missing dots. When the missing dot is detected, for example, the above-described cleaning by ink suction is used to recover. For details of the recovery method, refer to the aforementioned Japanese Patent Laid-Open No. 2000-225715.

  On the other hand, FIG. 4B is a test pattern for adjusting the ink droplet ejection timing. As described above, in a multi-pass type ink jet printer that performs printing while reciprocating the carriage 21 in the main scanning direction, printing, that is, ink droplet ejection, is performed both in the forward path and in the return path of the carriage 21 mainly to shorten the printing time. At this time, for example, the ink droplet ejection timing in the forward path of the carriage 21 and the ink droplet ejection timing in the backward path are slightly different due to, for example, a difference in forward / reverse rotation speed of the carriage motor 13 or a mechanical loss of the carriage drive mechanism. There is. Therefore, for example, the ink droplet ejection timing on the carriage return path is gradually shifted with respect to the constant ink droplet ejection timing on the carriage outbound path, and the timing at which the ink dots on the outbound path and the return path coincide is selected. In this case, the discharge timing indicated by reference numeral 5 is the discharge timing to be selected.

In the present embodiment, in any test pattern printing, the date and time when the test pattern is printed is printed closest to the test pattern.
Next, calculation processing executed in the control unit 31 for printing these test patterns will be described with reference to the flowchart of FIG. This arithmetic processing is executed when, for example, a test pattern print command is input from the operation panel 43 or the host computer 1.

In this calculation process, first, in step S1, it is determined whether or not the input test pattern print command is a missing dot detection command. If the input test pattern print command is a missing dot detection command, step S4 is performed. If not, the process proceeds to step S2.
In step S2, it is determined whether or not the input test pattern print command is a discharge timing adjustment command. If the input test pattern print command is a discharge timing adjustment command, the process proceeds to step S3. In this case, the process proceeds to step S6.

In step S3, the ejection timing adjustment test pattern print data as shown in FIG. 4b is read from the memory 33, and then the process proceeds to step S5.
In step S4, the dot missing detection test pattern print data as shown in FIG. 4a is read from the memory 33, and then the process proceeds to step S5.
In step S5, the test pattern is printed according to the arithmetic processing of FIG.

In step S6, neither a dot missing detection command nor a discharge timing adjustment command is input even though a test pattern print command is input, and an error display indicating that is displayed on the display panel 44 or the host. After being displayed on the computer 1, the main program is restored.
Next, the calculation process of FIG. 6 performed in step S5 of the calculation process of FIG. 5 will be described. In this calculation process, first, in step S51, it is determined whether or not there is a use input of a recorded print medium. If there is a use input of a recorded print medium, the process proceeds to step S52. The process proceeds to S58. The recorded print medium is a print medium that has been recorded at least once on the surface where the test pattern is to be used for printing, that is, a printed print medium. Input from the host computer 1 by the user.

  In step S52, it is determined whether or not a non-print area is designated by the user. If a non-print area is designated, the process proceeds to step S55, and if not, the process proceeds to step S53. This non-printing area corresponds to an unprinted area from which a test pattern is to be printed. For example, when a hatched area is designated in FIG. Thus, for example, the user inputs from the operation panel 43 or the host computer 1.

  In step S53, the scanner 11 is scanned with the scanner 11 while reading the state of the print surface of the print medium with the scanner 11, thereby scanning the non-printing area existing on the recorded print medium, and then the process proceeds to step S54. Transition. For example, as shown in FIG. 8, the scanning is performed by sequentially moving a frame having a size corresponding to the test pattern print area from the upper left of the print medium 22, for example, to the right. If the non-printing area is detected and the non-printing area cannot be detected, the scanning area is sequentially moved downward to detect the non-printing area in the same manner.

In step S54, it is determined whether or not a non-printing area having a size necessary for test pattern printing can be detected by scanning in step S53, and a non-printing area having a size necessary for test pattern printing can be detected. Shifts to step S55, otherwise shifts to step S59.
In step S55, a test pattern printing position, that is, a printing medium conveyance position is set based on the non-printing area designated by the user or the non-printing area detected in step S53, and then the process proceeds to step S56.

On the other hand, in step S58, a predetermined test pattern printing predetermined position is set, and then the process proceeds to step S56.
In step S56, the print medium is conveyed to the test pattern printing position, and then the process proceeds to step S57.
In step S57, according to the individual calculation process, the dot missing detection test pattern of FIG. 4a or the ejection timing adjustment test pattern of FIG. 4b is printed, and then the process returns to the main program.

On the other hand, in step S59, an error message indicating that a non-printing area of a size required for test pattern printing could not be detected is displayed, and the process returns to the main program.
According to this calculation process, when there is a test pattern print input, each test pattern is read from the memory 33 according to whether it is a missing dot detection command or a discharge timing adjustment command. Then, a non-printing area necessary for printing each test pattern is detected, and a test pattern is printed in the non-printing area. Therefore, according to the ink jet printer of the present embodiment, it is possible to use a recorded print medium for test pattern printing, or to use a single-leaf print medium repeatedly for test pattern printing. Can be reduced.

Moreover, test pattern printing can be performed appropriately by detecting a non-printing area large enough for test pattern printing on the printing medium.
Further, by printing the test pattern printing date and time together with the test pattern, it is possible to accurately grasp which test pattern is printed when and when the test pattern is repeatedly printed on a single print medium.

In addition, when a test pattern print area is specified, the test pattern is printed in the specified print area, so that, for example, the trouble of scanning the non-print area by the scan function is eliminated, and the test pattern print can be quickly performed. It can be carried out.
In addition, since the scanner function is provided, a non-printing area for test pattern printing can be automatically detected.

  In each of the above embodiments, only an example in which the ink jet printer of the present invention is applied to a so-called multi-pass ink jet printer has been described in detail. However, the ink jet printer of the present invention may be any type including a line head ink jet printer. It can be applied to a type of inkjet printer.

1 is a configuration diagram of a printing system showing an embodiment of an inkjet printer of the present invention. It is a schematic block diagram of the inkjet printer of FIG. It is explanatory drawing of the nozzle of the inkjet printer of FIG. It is explanatory drawing of the test pattern which tests the ink droplet discharge state of a nozzle. It is a flowchart of the arithmetic processing performed at the time of test pattern printing input. It is a flowchart of the subroutine performed by the arithmetic processing of FIG. It is explanatory drawing of the no-printing area designation | designated performed by the arithmetic processing of FIG. FIG. 7 is an explanatory diagram of non-printing area scanning performed in the arithmetic processing of FIG. 6.

Explanation of symbols

  1 is a host computer, 2 is an ink jet printer, 3 is a cap, 4 is a nozzle surface, 5 is a nozzle, 7 is an ink absorber, 8 is a cleaning device, 11 is a scanner, and 12 is a scanner motor.

Claims (4)

  In an ink jet printer that prints a predetermined test pattern on a print medium in order to test the discharge state of ink droplets discharged from the ink jet nozzles, no mark is detected on the print medium for a non-print area necessary for the test pattern printing. An ink jet printer comprising: a character area detecting means; and a test pattern printing means for printing the test pattern in a non-printing area detected by the non-printing area detecting means.  2. The ink jet printer according to claim 1, wherein the test pattern printing unit prints a test pattern printing date and time together with the test pattern.   3. The ink jet printer according to claim 1, wherein when the test pattern printing area is designated, the test pattern printing means prints the test pattern in the designated printing area.   The inkjet printer according to claim 1, wherein the non-printing area detecting unit has a scanner function.

Images