JP2007301752A - Printing device, printing system, and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive printing device that prints an image without image defects in a short period of time even when there are discharge-failure nozzles. <P>SOLUTION: The printing device is provided with a plurality of nozzles, which are arranged apart at prescribed intervals in a prescribed direction so as to print an image while discharging ink toward a medium, a detection part for detecting the discharge-failure nozzles from among a plurality of the nozzles, and a controller that is a controller for printing the image while using only the nozzles located apart at an interval of P times (P is an integer of ≥1) of the prescribed interval in the prescribed direction so as to decide the P-fold interval on the basis of the detection result of the detection part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing apparatus, a printing system, and a printing method for printing an image by ejecting ink droplets toward a medium.

2. Related Art Ink jet printers that print images by forming dots on paper as a medium by ejecting ink droplets from nozzles have become widespread. The nozzles of this printer may become clogged due to ink sticking or the like, and ink droplets may not be ejected normally. For this reason, normally, the presence or absence of a defective nozzle is detected, and if there is a defective nozzle, printing is stopped and the nozzle is cleaned.
However, when a printed material is needed immediately, it may be convenient if printing without image defects can be performed without cleaning even when a nozzle with defective ejection is detected.

In this regard, for example, in Patent Document 1, spare nozzles are arranged in parallel with the nozzles, and when a defective nozzle is detected, the spare nozzles are used instead of the nozzles to generate an image. Is disclosed.
JP 2003-118149 A

However, according to the method of Patent Document 1, the number of components of the printer increases by the number of spare nozzles, and the manufacturing cost increases.
The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive printing apparatus capable of printing an image free from image defects in a short time even when there is a nozzle with defective ejection. .

The main invention for achieving the object is as follows:
A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. And a controller that determines based on the detection result of the printing unit.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

 At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. And a controller that determines based on the detection result of the printing unit.

According to such a printing apparatus, even when there is a defective nozzle, printing can be performed in as short a time as possible while preventing image defects due to the defective nozzle. That is, since the interval of the nozzles used for printing in the predetermined direction is determined based on the detection result of the nozzles with defective discharge, the nozzles used for printing are equally spaced with respect to the predetermined direction while the nozzles with defective discharge are replaced. It can be set every other time. As a result, it is possible to print images normally using nozzles located at regular intervals without performing cleaning to restore the ejection state normally, and for a short time without stopping printing as much as possible. Thus, printing without image defects can be executed.
In addition, since it is not necessary to provide a spare nozzle, the printing apparatus can be made inexpensive.

In such a printing apparatus,
The detection operation of detecting the ejection failure nozzle by the detection unit is performed for each medium before printing on the medium,
It is desirable to determine the P-fold interval for each medium based on the detection result of the detection operation.
According to such a printing apparatus, the P times interval is determined based on the detection result corresponding to each medium. Therefore, it is possible to print an image with the highest resolution among them while reliably preventing image defects due to defectively ejected nozzles.

In such a printing apparatus,
In the case of a detection result that there is no defective nozzle,
It is desirable that the controller performs printing using nozzles positioned at the predetermined intervals.
According to such a printing apparatus, the predetermined direction can be printed at a resolution corresponding to the predetermined interval, and a high-quality image can be printed.

In such a printing apparatus,
The P-fold interval is determined as either one or two times the predetermined interval,
In the case of a detection result that there is a nozzle with a defective discharge, and when any nozzle located at the double interval does not correspond to the nozzle with a defective discharge,
It is preferable that the controller performs printing using nozzles positioned at intervals of the double.
According to such a printing apparatus, since the image is normally printed using the nozzles positioned at equal intervals, printing without image defects can be executed in a short time without stopping printing as much as possible. .

In such a printing apparatus,
When the nozzles located at twice the intervals correspond to the nozzles with defective ejection,
It is preferable that the controller performs a cleaning operation on the defective nozzles in order to eliminate the defective discharge.
According to such a printing apparatus, it is possible to perform printing while reliably preventing image defects caused by defective nozzles.

In such a printing apparatus,
When performing printing using the nozzles positioned at the predetermined intervals, the controller uses image data with a predetermined resolution in the predetermined direction, and
When printing is performed using nozzles located at intervals of the P times, image data having a resolution of 1 / P of the predetermined resolution may be used.

In such a printing apparatus,
A moving mechanism that relatively moves the plurality of nozzles and the medium in an intersecting direction that intersects the predetermined direction may be provided.

In such a printing apparatus,
The moving mechanism is a transport mechanism that transports the medium in the intersecting direction;
The plurality of nozzles are fixed at a predetermined position in the intersecting direction and arranged so that ink droplets are ejected over the entire width of the medium in the predetermined direction.
It is preferable that ink droplets are ejected from the plurality of nozzles and the image is printed on the medium while the medium is transported in the intersecting direction.
According to such a printing apparatus, since it functions as a so-called line printer, printing can be performed in a short time.

A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward the medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. A controller that determines based on the detection result of the part,
The detection operation for detecting the ejection failure nozzles by the detection unit is performed for each medium before printing on the medium, and for each medium based on the detection result of the detection operation, the P times. Determine the interval,
In the case of a detection result that there is no defective nozzle, the controller performs printing using the nozzles located at the predetermined intervals,
The P-fold interval is determined to be one or two times the predetermined interval, and in the case of a detection result that there is a nozzle with the ejection failure, and every two times the interval. If none of the positioned nozzles corresponds to the defective ejection nozzle, the controller performs printing using the nozzles positioned at intervals of the double,
When the nozzles located at twice the interval correspond to the ejection failure nozzle, the controller performs a cleaning operation on the ejection failure nozzle to eliminate the ejection failure,
When printing is performed using the nozzles positioned at the predetermined intervals, the controller uses image data having a predetermined resolution in the predetermined direction and performs printing using the nozzles positioned at intervals of the P times. In this case, image data having a resolution of 1 / P of the predetermined resolution is used.
A moving mechanism for relatively moving the plurality of nozzles and the medium in a crossing direction crossing the predetermined direction;
The moving mechanism is a transport mechanism that transports the medium in the intersecting direction, and the plurality of nozzles are fixed at a predetermined position in the intersecting direction and ink is formed over the entire width of the medium in the predetermined direction. A printing apparatus, wherein the printing apparatus is arranged so that droplets are ejected, and the image is printed on the medium by ejecting ink droplets from the plurality of nozzles while transporting the medium in the intersecting direction.
According to such a printing apparatus, since almost all the effects described above are exhibited, the object of the present invention is achieved most effectively.

A printing system comprising a computer and a printing device connected to the computer so as to be able to communicate data for printing,
The printing apparatus includes:
A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. It is also possible to realize a printing system that includes a controller that determines based on the detection result of each copy.

Also, a plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward the medium to print an image, and P times the predetermined interval in the predetermined direction (P is an integer of 1 or more) And a controller for printing the image using only nozzles positioned at intervals of
Detecting an ejection failure nozzle from the plurality of nozzles;
It is also possible to realize a printing method comprising the step of determining the P times interval based on the detection result of the ejection failure nozzle.

=== Configuration of Printing System 100 ===
An embodiment of a printing system 100 will be described with reference to the drawings.
FIG. 1 is an explanatory diagram showing an external configuration of the printing system 100. The printing system 100 includes a printer 1, a computer 110, a display device 120, an input device 130, and a recording / reproducing device 140. The printer 1 is a printing apparatus that prints an image on a medium such as paper, cloth, or film. The computer 110 is communicably connected to the printer 1 and outputs print data corresponding to the image to be printed to the printer 1 in order to cause the printer 1 to print an image.

  A printer driver is installed in the computer 110. The printer driver is a program for causing the display device 120 to display a user interface and converting image data output from the application program into print data. This printer driver is recorded on a recording medium (computer-readable recording medium) such as a flexible disk FD or a CD-ROM. Alternatively, the printer driver can be downloaded to the computer 110 via the Internet. This program is composed of codes for realizing various functions.

=== Configuration of Printer 1 ===
<Configuration of Inkjet Printer 1>
FIG. 2 is a block diagram of the overall configuration of the printer 1. FIG. 3 is a longitudinal sectional view of the printer 1. FIG. 4 is a perspective view for explaining the internal configuration of the printer 1. Hereinafter, the basic configuration of the printer 1 will be described by taking a line printer as an example.

  As shown in FIG. 2, the printer 1 includes a transport unit 20, a head unit 40, a nozzle cleaning unit 70, a nozzle clogging inspection unit 80, a detector group 50, a display unit 65, an operation unit 66, and a controller 60. The printer 1 that has received the print data from the computer 110 as an external device controls each unit (the transport unit 20, the head unit 40, etc.) by the controller 60. The controller 60 controls each unit based on the print data received from the computer 110 and prints an image on paper. The situation in the printer 1 is monitored by a detector group 50, and the detector group 50 outputs a detection result to the controller 60. The controller 60 controls each unit based on the detection result output from the detector group 50.

  The transport unit 20 (corresponding to a transport mechanism) is for transporting paper in the transport direction. As shown in FIG. 3, the transport unit 20 includes a paper feed roller 21, a transport motor (not shown), an upstream transport roller 23 </ b> A and a downstream transport roller 23 </ b> B, and a transport belt 24. The paper feed roller 21 is a roller for feeding the paper in the paper feed tray 22 into the printer. When a transport motor (not shown) rotates, the upstream transport roller 23A and the downstream transport roller 23B rotate, and the transport belt 24 rotates. The paper fed by the paper feed roller 21 is transported by the transport belt 24 to a printable area (area facing the print head 41). When the transport belt 24 transports the paper, the paper moves in the transport direction with respect to the head unit 40. The paper that has passed through the printable area is discharged to the outside by the transport belt 24. Note that the paper being transported is electrostatically attracted or vacuum attracted to the transport belt 24.

  The head unit 40 is for ejecting ink droplets onto paper. The head unit 40 has a print head 41, and a plurality of nozzles for ejecting ink droplets are provided on the lower surface 41 a of the print head 41. Then, by ejecting ink droplets from the nozzles onto the paper being conveyed, dots are formed on the paper and an image is printed on the paper. The print head 41 is a so-called line head, and the nozzles are provided at predetermined intervals over the entire width in the paper width direction (see FIG. 4) orthogonal to the transport direction. Therefore, the print head 41 can form dots at a predetermined printing resolution at a time with respect to the area corresponding to the paper width. The configuration of the print head 41 will be described later.

  The nozzle cleaning unit 70 is for eliminating nozzle clogging (nozzle ejection failure) of the print head 41. As shown in FIG. 3, the cleaning unit 70 is provided on the downstream side in the transport direction on the side of the print head 41. Then, by rotating the print head 41 around the axis 41b along the paper width direction, the nozzles of the print head 41 are brought into a state where the nozzles can be cleaned by facing the cleaning unit 70. The configuration of the cleaning unit 70 will be described later.

  The nozzle clogging inspection unit 80 (corresponding to the detection unit) is for inspecting nozzle clogging of the print head 41. The inspection unit 80 includes a laser light source 81 and a light receiver 82 (see FIG. 12). The presence or absence of nozzle clogging is detected based on whether or not the laser light emitted from the laser light source 81 to the light receiver 82 is blocked by the ink droplets ejected from the nozzles. The inspection unit 80 will be described later.

  The detector group 50 includes a rotary encoder (not shown), a paper detection sensor 53, and the like. The rotary encoder detects the rotation amount of the upstream side conveyance roller 23A and the downstream side conveyance roller 23B. Based on the detection result of the rotary encoder, the amount of paper transport can be detected. The paper detection sensor 53 detects the position of the leading edge of the paper being fed, and is provided between the paper feed roller 21 and the upstream transport roller 23A as shown in FIG.

  The controller 60 is a control unit for controlling the printer 1. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 transmits and receives data between the computer 110 which is an external device and the printer 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM and an EEPROM. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

<Print head 41>
5, 6 </ b> A, and 6 </ b> B are explanatory diagrams of the nozzle arrangement on the lower surface 41 a of the print head 41. FIG. 5 shows the whole, and FIGS. 6A and 6B show a part of the enlarged view.

  As shown in FIG. 5, on the lower surface 41a of the print head 41, unit heads 42 having a plurality of nozzles are arranged in a staggered manner across the paper width direction, so that for each ink color of CMYK, Nozzles are arranged at predetermined intervals (1/720 inch) in the paper width direction. As a result, the print head 41 can function as a line head having a maximum resolution in the paper width direction of 720 dpi (dots / inch). In other words, the print head 41 once sets dots for the paper width at intervals of a minimum of 1/720 inch in the paper width direction. Can be formed.

  More specifically, as shown in the enlarged view of FIG. 6A, each unit head 42 has the same configuration. That is, each unit head 42 has a nozzle row K for black ink, a nozzle row C for cyan ink, A magenta ink nozzle row M and a yellow ink nozzle row Y are provided. Each nozzle row includes 360 nozzles for ejecting ink droplets, and the 360 nozzles in each nozzle row are arranged at a nozzle pitch of 1/360 inch along the paper width direction.

  When such unit heads 42 are arranged at the arrangement position in the transport direction, as shown in FIG. 5, the first unit head group 43A, the second unit head group 44A, the third unit head group 43B, and the fourth unit head group. 44B is roughly divided into four groups. Each of the unit head groups 43A, 44A, 43B, and 44B is configured by arranging five unit heads 42 in the paper width direction, with an interval corresponding to one unit head between the adjacent unit heads 42. Is arranged. The unit heads 42 of the third unit head group 43B are interpolated at positions where the unit heads 42 are not arranged in the first unit head group 43A. Conversely, the unit heads 42 of the third unit head group 43B are The unit heads 42 of the first unit head group 43A are interpolated at positions where they are not arranged, that is, they are arranged while complementing each other in the paper width direction. As a result, as shown in FIG. 6A, the first unit head group 43A and the third unit head group 43B align the nozzles at intervals of 1/360 inch over the entire width in the paper width direction.

  A similar positional relationship is established between the second unit head group 44A and the fourth unit head group 44B. As a result, as shown in FIG. 6B, the second unit head group 44A and the fourth unit head group 44B. The nozzles are aligned at intervals of 1/360 inch over the entire width in the paper width direction.

  A head group pair (hereinafter referred to as a first head group pair) including the first unit head group 43A and the third unit head group 43B, a second unit head group 44A, and a fourth unit head group 44B. The head group pairs (hereinafter referred to as second head group pairs) are arranged so as to be shifted from each other in the paper width direction by half the nozzle pitch (see FIG. 6B). For this reason, the nozzles are substantially arranged at an interval of 1/720 inch, which is a half pitch of the nozzle pitch (1/360 inch), in the paper width direction. No. 41 can function as a line head having a print resolution in the paper width direction of 720 dpi. That is, if both the first head group pair and the second head group pair are used, printing can be performed at a printing resolution of 720 dpi in the paper width direction.

  By the way, if only one of the first head group pair and the second head group pair is used and the other head group pair is not used, the print head 41 can be used in the paper width direction. It can also function as a line head with a printing resolution of 360 dpi.

  Then, printing is performed at a print resolution of 720 dpi using both the first head group pair and the second head group pair as shown in FIG. 7A, or the first head group pair and the second head group pair as shown in FIGS. 7B and 7C. Whether to print at a print resolution of 360 dpi using any one of the second head group pair is determined by the controller 60 based on the nozzle clog inspection result transmitted from the nozzle clog inspection unit 80, as will be described later.

  Each nozzle # 1 to # 360 in each nozzle row of the unit head 42 is provided with a piezo element (not shown) as a drive element for ejecting ink droplets. When a voltage is applied to the piezo element, the piezo element expands in accordance with the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts in accordance with the expansion and contraction of the piezo element, and the ink corresponding to the contraction is ejected from the nozzles # 1 to # 360 of the respective ink colors as ink droplets. The

  FIG. 8 is a block diagram of a drive circuit 220 for driving the nozzles # 1 to # 360. The drive circuit 220 is provided for each nozzle row, and includes an original drive signal generator 221 and a plurality of mask circuits 222. Basically, each drive circuit 220 is different in that the output time of the original signal ODRV of the original drive signal generation unit 221 is different depending on the position in the transport direction of the nozzle row that the drive circuit 220 is in charge of, The other points are almost the same. That is, when the nozzle row in charge of the drive circuit is located on the upstream side than the nozzle row located on the most downstream side in the transport direction, the drive circuit 220 for the downstream nozzle row The difference is that the original signal ODRV is output with a delay corresponding to the separation distance between the nozzle rows, and the configuration of each drive circuit 220 is substantially the same in other points. Therefore, in the following description, only the driving circuit 220 for one nozzle row will be described.

  The original drive signal generator 221 generates an original signal ODRV that is used in common by the nozzles # 1 to # 360. This original signal ODRV is a signal including two pulses, a first pulse PW1 and a second pulse PW2, as shown in the lower part of FIG. Is generated for each section in the transport direction based on the output of the rotary encoder. That is, each time the paper is transported for the interval, the pulses PW1 and PW2 are generated.

  The size of the section is changed according to the printing resolution in the transport direction. That is, when the print resolution in the transport direction is 720 dpi, the section is 1/720 inch as shown in FIG. 9A, while in the case of 360 dpi, it is 1/360 inch as shown in FIG. 9B. . Further, the amplitudes of the pulses PW1 and PW2 are also changed according to the printing resolution in the transport direction. That is, as shown in FIGS. 9A and 9B, when the printing resolution in the transport direction is 720 dpi, the size is reduced to approximately half of the amplitude in the case of 360 dpi, thereby the ink droplet size suitable for the printing resolution is obtained. Adjusted.

  The original signal ODRV is output to each mask circuit 222. The mask circuit 222 is provided corresponding to each piezo element that drives each nozzle. Each mask circuit 222 receives the original signal ODRV from the original drive signal generator 221 and the pixel data PRT based on the print data. This pixel data PRT is data corresponding to the pixels constituting the image to be printed, and is binary data having 2-bit information for one pixel. Each bit corresponds to the first pulse PW1 and the second pulse PW2, respectively. The mask circuit 222 is a gate for blocking or passing the original signal ODRV in accordance with the pixel data PRT. After passing through the mask circuit 222, the original signal ODRV becomes a drive signal DRV for driving the piezo element, and is output toward the piezo element of each nozzle. The piezo element of each nozzle is driven based on the drive signal DRV from the mask circuit 222 to discharge ink. For example, as shown in FIG. 10, when the pixel data PRT is “00”, the drive signal DRV in which both the pulses PW1 and PW2 of the original signal ODRV are blocked by the mask circuit 222 is output to the piezo element, and ink droplets are generated. In the case of “01”, only the pulse PW1 is passed and a small size ink droplet is ejected. In the case of “10”, only the pulse PW2 is passed and a medium size ink droplet is ejected. In the case of “11”, both the pulses PW1 and PW2 are passed and a large ink droplet is ejected.

  As the print data, two types of print data having a print resolution of 720 × 720 dpi and 360 × 360 dpi in the paper width direction × conveyance direction are transmitted from the computer 110 to the printer 1 and recorded in the memory 63. Each print data has pixel data corresponding to the print resolution. That is, the print data of 720 × 720 dpi has pixel data for each pixel of 1/720 inch square, and the print data of 360 × 360 dpi has pixel data for each pixel of 1/360 inch square.

  When printing based on 720 × 720 dpi print data, the head group pair to be used is both the first head group pair and the second head group pair. In this case, the first head group pair In addition, the pixel data is input in association with the mask circuit 222 of each nozzle positioned every 1/720 inch in the second head group pair in order from one end to the other end in the paper width direction.

  On the other hand, when printing is performed based on 360 × 360 dpi print data, the head group pair to be used is either the first head group pair or the second head group pair. Pixel data is input in association with the mask circuit 222 of each nozzle located every 1/360 inch in one head group pair in order from one end to the other end in the paper width direction.

<Nozzle cleaning unit 70>
11A to 11D are explanatory views of the cleaning unit 70 and are shown in a longitudinal sectional view. As illustrated, the cleaning unit 70 is disposed on the downstream side in the transport direction on the side of the print head 41. Then, as shown in FIG. 11A, the print head 41 in which the nozzles face downward during printing is turned around the axis 41b along the paper width direction as shown in FIG. 11B, and the nozzles are directed toward the cleaning unit 70. Thus, the cleaning can be performed.

  The cleaning unit 70 includes a turning drive motor (not shown) for turning the print head 41 and a capping device 71.

  The capping device 71 seals the nozzles of the print head 41, and as a component thereof, the capping device 71 is in close contact with the peripheral portion of the surface 41a of the surface of the print head 41 where the nozzles are formed and covers all the nozzles. And a moving mechanism (not shown) for moving the cap member 72 to and from the print head 41. 11B, when the print head 41 is turned by the turning drive motor and the nozzle faces the cleaning unit 70, the moving mechanism moves the cap member 72 toward the print head 41 as shown in FIG. 11C. The nozzle is sealed by the cap member 72 by being moved. On the other hand, when the print head 41 is turned from this state to turn the nozzle downward as shown in FIG. 11D, the moving mechanism moves the cap member 72 away from the print head 41 as shown in FIG. 11D. And the cap member 72 is moved.

  A tube 73 for discharging the ink in the space inside the cap member 72 to the outside is connected to the cap member 72, and the tube 73 is connected to the waste liquid tank 75 via the pump device 74. Has been. Therefore, as shown in FIG. 11C, when the pump device 74 is started in a state in which the nozzles are sealed by the cap member 72, the inner space of the cap member 72 becomes negative pressure, thereby sucking ink from all the nozzles n. Thus, the nozzle clogging is eliminated, that is, the nozzle is cleaned. The sucked ink is stored in the waste liquid tank 75.

<Nozzle clogging inspection unit 80>
FIG. 12 is an explanatory diagram of the nozzle clogging inspection unit 80 and is a view taken in the direction of arrows XII-XII in FIG. 11A. The nozzle clogging inspection unit 80 includes, for example, a laser light source 81 and a light receiver 82 provided inside the cap member 72 of the capping device 71, and a determination unit (not shown) that outputs an output voltage from the light receiver 82. have.

  The laser light source 81 and the light receiver 82 are provided for each arrangement position of the nozzle rows in the transport direction. In this example, as shown in FIG. 5, there are four unit head groups 43A, 44A, 43B, 44B in the transport direction, and each of the unit head groups 43A, 44A, 43B, 44B has CMYK values in the transport direction. Since the nozzle rows are arranged, there are 16 nozzle rows in the transport direction. Accordingly, as shown in FIG. 12, 16 sets of laser light sources 81 and light receivers 82 are provided. ing.

  Each of the laser light sources 81 and the light receivers 82 is installed such that the optical axis direction thereof is aligned with the paper width direction as the nozzle alignment direction. The laser light sources 81 and the light receivers 82 are disposed between the laser light sources 81 and the light receivers 82. The light source 81 and the light receiver 82 are installed at both ends in the paper width direction so as to sandwich all the nozzles in the transport direction positions in charge of inspection.

  The light receiver 82 outputs a voltage corresponding to the amount of received light. Therefore, when the ink droplet ejected from the nozzle blocks the optical path of the laser beam, the output voltage changes. Based on the change in the output voltage, the determination unit determines whether or not the ink droplet is ejected.

  As an inspection procedure, for example, ink droplets are ejected one nozzle at a time from one end to the other end in the paper width direction, and whether or not the laser beam is blocked by the ink droplets is inspected one by one. Here, if there is no change in the output voltage that should occur after a predetermined time has elapsed since the application of the drive signal DRV for ejecting ink droplets to the piezo element, the nozzle is determined to be clogged.

  The nozzle clogging inspection results are collected for each head group pair by the determination unit and output to the controller 60. That is, if even one of the nozzles of the first head group pair (the first unit head group 43A and the third unit head group 43B) is clogged, “the first head group pair has nozzle clogging”. On the other hand, if there is no nozzle clogging, it is determined that “the first head group pair has no nozzle clogging”. The same applies to the second head group pair (second unit head group 44A and fourth unit head group 44B).

=== Print processing ===
FIG. 13 is a flowchart of the printing process. Each operation described below is executed by the controller 60 controlling each unit in accordance with a program stored in the memory 63. This program has code for executing each operation.

  First, the controller 60 receives print data from the computer 110 via the interface unit 61 (S102). However, as will be described later, the printer 1 performs a nozzle clogging inspection for each sheet of paper, and determines the printing resolution according to the inspection result. For this reason, as the print data, two types of print data of print data of 360 dpi × 360 dpi and print data of 720 dpi × 720 dpi are received as the print resolution in the paper width direction × conveyance direction. These print data are stored in the memory 63. These print data are generated by the printer driver based on the same image data, that is, differ only in that the print resolution is different.

  Next, the controller 60 receives the print number information (S104). The print number information is information indicating the number of sheets to be continuously printed based on the print data, and is input by the user from the user interface of the computer 110 or the like.

  Then, the controller 60 instructs the nozzle clogging inspection unit 80 to execute the nozzle clogging inspection (S106). When an inspection result is received from the nozzle clogging inspection unit 80 (S108), the controller 60 selects a print resolution for printing on paper and a head group pair used for printing according to the inspection result (S110 to S110). S126).

  That is, when the inspection result is “no nozzle clogging in both the first head group pair and the second head group pair”, the process branches to YES in both step S110 and step S112, and as a result, the print resolution is 720. X720 dpi is determined, and both the first head group pair and the second head group pair are selected as the head group pair used for printing (S114 and S116). In the subsequent “printing operation” in step S140, an image is printed at a print resolution of 720 × 720 dpi using the nozzles of both the first head group pair and the second head group pair based on the print data of 720 × 720 dpi. Print. The “printing operation” in step S140 will be described later.

 On the other hand, if the inspection result is “the first head group pair has no nozzle clogging and the second head group pair has nozzle clogging”, the process branches to Yes in step S110, but branches to No in step S112. The print resolution is determined to be 360 × 360 dpi, and only the first head group pair is selected as the head group pair used for printing (S118, S120). In the subsequent “printing operation” in step S140, an image is printed at a printing resolution of 360 × 360 dpi using only the nozzles of the first head group pair based on the printing data of 360 × 360 dpi. An image can be printed immediately without causing image defects due to the above.

 Conversely, if the test result is “the first head group pair is clogged with nozzles and the second head group pair is not clogged”, the process branches to No in step S110 and to YES in step S122. As a result, the print resolution is determined to be 360 × 360 dpi, and only the second head group pair is selected as the head group pair used for printing (S124, S126). In the subsequent “printing operation” in step S140, based on the print data of 360 × 360 dpi, an image is printed at a print resolution of 360 × 360 dpi using only the second head group pair, thereby causing nozzle clogging. An image can be printed immediately without causing image defects.

  In the case where the inspection result is “nozzle clogged in both the first head group pair and the second head group pair”, if the printing operation is performed as it is, an image defect due to nozzle clogging occurs. For this reason, when branching to No in both step S110 and step S122, the nozzle cleaning process of step S130 is performed. This cleaning process is performed by the nozzle cleaning unit 70 described above. When the nozzle cleaning process is completed, the process returns to the above-described step S106, and “nozzle clogging inspection” is performed again.

  When printing is performed in the “printing operation” step of S140 through any of the above-described steps S116, S120, and S126, the process proceeds to step S150.

 In step S150, the controller 60 determines whether or not the number of prints indicated by the print number information has been printed. When the number of printed sheets has been printed, the series of “print processing” is terminated. On the other hand, if the number has not reached, the process returns to the above-described step S106, and each operation from the “nozzle clogging inspection” (S106) to the “printing operation” (S140) is performed to print on the next paper. This is repeated until the number of printed sheets reaches the number indicated by the printed sheet number information.

  Here, the “printing operation” in step S140 will be described with reference to FIGS. FIG. 14 is a flowchart of the “printing operation” in step S140.

  First, the controller 60 performs a paper feeding operation (S141). The paper feeding operation is an operation of picking up only one sheet from the paper stocked in the paper feed tray 22 and transporting it until the leading edge of the paper reaches the transport belt 24. That is, the controller 60 drives the paper feed motor to rotate the paper feed roller 21 to feed the paper in the paper feed tray 22 toward the transport belt 24. When the leading edge of the paper reaches the transport belt 24, the paper feed is performed. Stop driving the motor. The arrival of the leading edge of the paper at the conveyance belt 24 is detected by a paper detection sensor 53.

  Next, the controller 60 starts a transport operation (S143). The transport operation is an operation in which the transport belt 24 is rotated by the transport motor to transport the paper to the downstream side in the transport direction at a predetermined transport speed. During this transport operation, an ink discharge operation for discharging ink droplets from the print head 41 is performed (S145).

  In the ink ejection operation, ink droplets are intermittently ejected from each nozzle of the print head 41 based on the print data. As a result, a plurality of ink droplets are printed on the paper at a pitch corresponding to the print resolution in the same direction along the transport direction. Are formed side by side, and in the paper width direction, dots are formed at a pitch corresponding to the printing resolution in the same direction. For example, when the print resolution is 720 × 720 dpi, dots are formed at a pitch of 1/720 inch with respect to both the paper width direction and the conveyance direction, while when the print resolution is 360 × 360 dpi, the paper width direction In addition, dots are formed at a pitch of 1/360 dpi in both directions of the transport direction. This ink ejection operation ends when the pixel data to be printed on the paper being printed disappears from the print data.

After printing is performed in this manner, when the tail end of the paper reaches the downstream side in the transport direction from the print head 41, the transport operation is terminated (S147), and the paper discharge operation is performed (S149).
The paper discharge operation is an operation in which the paper is transported to the downstream side at a speed higher than the transport speed, and the paper is ejected outside the printer. Then, upon completion of this discharge operation, the “printing operation” in step S140 ends.

=== Other Embodiments ===
The above embodiments are mainly described with respect to the printing system, but it goes without saying that the disclosure includes a printing apparatus, a printing method, and the like.
Moreover, although the printing system etc. as one embodiment were demonstrated, said embodiment is for making an understanding of this invention easy, and is not for limiting and interpreting this invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About Printer 1>
In the above-described embodiment, the printer 1 has been described as the printing apparatus. However, the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional modeling machine, liquid vaporization apparatus, organic EL manufacturing apparatus (particularly polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technique as that of the present embodiment may be applied to various recording apparatuses to which an ink jet technique is applied such as an apparatus and a DNA chip manufacturing apparatus. These methods and manufacturing methods are also within the scope of application.

<About ink>
In the above-described embodiment, dye ink or pigment ink is ejected from the nozzles of the printer 1 from the nozzles. However, the ink ejected from the nozzle is not limited to such ink.

<Ink colors used for printing>
In the above-described embodiment, multicolor printing in which four inks of cyan (C), magenta (M), yellow (Y), and black (K) are ejected onto paper to form dots has been described as an example. The ink color is not limited to this. For example, in addition to these ink colors, six colors may be used using inks such as light cyan (light cyan, LC) and light magenta (light magenta, LM), or eight colors using light black LK and lighter black LLK. good. Conversely, monochrome printing may be performed using only one of the four ink colors.

<Print resolution>
In the above-described embodiment, as an example of the plurality of nozzles arranged at the predetermined intervals, nozzles are arranged at intervals of 1/720 inch, while the print resolution corresponding to the predetermined intervals is 720 dpi, and the predetermined intervals. The print resolution corresponding to the P-fold interval has been described by taking 360 dpi when P is 2 as an example, but the present invention is not limited to this. For example, the predetermined interval may be 1/1440 inches, the print resolution corresponding to the predetermined interval may be 1440 dpi, and P may be 4, and the print resolution corresponding to P times the predetermined interval may be 360 dpi. However, if the P is too large, the appearance looks large between paper printed at a printing resolution corresponding to P times the predetermined interval and paper printed at a printing resolution corresponding to the predetermined interval. Since P changes, it is desirable that P is not larger than 2.

1 is an explanatory diagram of an external configuration of a printing system 100. FIG. 1 is a block diagram of an overall configuration of a printer 1. FIG. 1 is a longitudinal sectional view of a printer 1. FIG. 2 is a perspective view for explaining an internal configuration of the printer 1. 4 is an explanatory diagram of nozzle arrangement on a lower surface 41a of the print head 41. FIG. 4 is an explanatory diagram of nozzle arrangement on a lower surface 41a of the print head 41. FIG. 4 is an explanatory diagram of nozzle arrangement on a lower surface 41a of the print head 41. FIG. FIG. 7 is an explanatory diagram when printing is performed at a print resolution of 720 dpi. FIG. 10 is an explanatory diagram when printing is performed at a print resolution of 360 dpi. FIG. 10 is an explanatory diagram when printing is performed at a print resolution of 360 dpi. It is a block diagram of a drive circuit 220 for driving each nozzle # 1 to # 360. FIG. 9A is a waveform diagram of the original signal ODRV with a print resolution in the transport direction of 720 dpi, and FIG. 9B is a waveform diagram of the original signal ODRV with the print resolution of 360 dpi. It is explanatory drawing of the size of the ink droplet discharged based on pixel data PRT. 11A to 11D are explanatory diagrams of the cleaning unit 70. FIG. It is explanatory drawing of the nozzle clogging inspection unit 80, Comprising: It is the XII-XII arrow line view in FIG. 11A. It is a flowchart of a printing process. FIG. 14 is a flowchart of “printing operation” in step S140 in the printing process of FIG. 13.

Explanation of symbols

1 printer,
20 transport unit, 21 paper feed roller, 22 paper feed tray,
23A upstream conveying roller, 23B downstream conveying roller, 24 conveying belt,
40 head units,
41 print head, 41a lower surface, 41b axis,
42 unit heads,
43A first unit head group, 43B third unit head group,
44A second unit head group, 44B fourth unit head group,
50 detector groups, 53 paper detection sensors,
60 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit,
65 display section, 66 operation section,
70 nozzle cleaning unit, 71 capping device, 72 cap member,
73 Tube, 74 Pump device, 75 Waste liquid tank,
80 nozzle clogging inspection unit, 81 laser light source, 82 light receiver,
100 printing system, 110 computer,
120 display device, 130 input device, 140 recording / reproducing device,
220 drive circuit, 221 original drive signal generator, 222 mask circuit

Claims (11)

A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. And a controller that determines based on the detection result of the printing unit. The printing apparatus according to claim 1,
The detection operation of detecting the ejection failure nozzle by the detection unit is performed for each medium before printing on the medium,
The printing apparatus, wherein the P-fold interval is determined for each medium based on a detection result of the detection operation. The printing apparatus according to claim 1 or 2,
In the case of a detection result that there is no defective nozzle,
The printing apparatus, wherein the controller performs printing using nozzles positioned at the predetermined intervals. The printing apparatus according to any one of claims 1 to 3,
The P-fold interval is determined as either one or two times the predetermined interval,
In the case of a detection result that there is a nozzle with a defective discharge, and when any nozzle located at the double interval does not correspond to the nozzle with a defective discharge,
The printing apparatus, wherein the controller performs printing using nozzles positioned at intervals of the double. The printing apparatus according to claim 4,
When the nozzles located at twice the intervals correspond to the nozzles with defective ejection,
The printing apparatus according to claim 1, wherein the controller performs a cleaning operation on the defective nozzles in order to eliminate the defective discharge. The printing apparatus according to any one of claims 1 to 5,
When performing printing using the nozzles positioned at the predetermined intervals, the controller uses image data with a predetermined resolution in the predetermined direction, and
When printing is performed using nozzles positioned at intervals of P times, image data having a resolution of 1 / P of the predetermined resolution is used. The printing apparatus according to any one of claims 1 to 6,
A printing apparatus comprising: a moving mechanism that relatively moves the plurality of nozzles and the medium in a crossing direction crossing the predetermined direction. The printing apparatus according to claim 7.
The moving mechanism is a transport mechanism that transports the medium in the intersecting direction;
The plurality of nozzles are fixed at a predetermined position in the intersecting direction and arranged so that ink droplets are ejected over the entire width of the medium in the predetermined direction.
A printing apparatus, wherein the image is printed on the medium by ejecting ink droplets from the plurality of nozzles while transporting the medium in the intersecting direction. A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. A controller that determines based on the detection result of the part,
The detection operation for detecting the ejection failure nozzles by the detection unit is performed for each medium before printing on the medium, and for each medium based on the detection result of the detection operation, the P times. Determine the interval,
In the case of a detection result that there is no defective nozzle, the controller performs printing using the nozzles located at the predetermined intervals,
The P-fold interval is determined to be one or two times the predetermined interval, and in the case of a detection result that there is a nozzle with the ejection failure, and every two times the interval. If none of the positioned nozzles corresponds to the defective ejection nozzle, the controller performs printing using the nozzles positioned at intervals of the double,
When the nozzles located at twice the interval correspond to the ejection failure nozzle, the controller performs a cleaning operation on the ejection failure nozzle to eliminate the ejection failure,
When printing is performed using the nozzles positioned at the predetermined intervals, the controller uses image data having a predetermined resolution in the predetermined direction and performs printing using the nozzles positioned at intervals of the P times. In this case, image data having a resolution of 1 / P of the predetermined resolution is used.
A moving mechanism for relatively moving the plurality of nozzles and the medium in a crossing direction crossing the predetermined direction;
The moving mechanism is a transport mechanism that transports the medium in the intersecting direction, and the plurality of nozzles are fixed at a predetermined position in the intersecting direction and ink is formed over the entire width of the medium in the predetermined direction. A printing apparatus, wherein the printing apparatus is arranged so that droplets are ejected, and the image is printed on the medium by ejecting ink droplets from the plurality of nozzles while transporting the medium in the intersecting direction. A printing system comprising a computer and a printing device connected to the computer so that data for printing can be communicated,
The printing apparatus includes:
A plurality of nozzles arranged at predetermined intervals in a predetermined direction to eject ink droplets toward a medium and print an image;
A detection unit for detecting a nozzle having an ejection failure from the plurality of nozzles;
A controller for printing the image using only nozzles located at intervals of P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction, wherein the P times interval is detected. And a controller that determines based on the detection result of the printing unit. A plurality of nozzles arranged at predetermined intervals in a predetermined direction to print an image by ejecting ink droplets toward the medium, and an interval P times the predetermined interval (P is an integer of 1 or more) with respect to the predetermined direction A controller for printing the image using only nozzles located every other, and a printing method executed by a printing apparatus comprising:
Detecting an ejection failure nozzle from the plurality of nozzles;
And a step of determining the P times interval based on a detection result of the ejection failure nozzle.

Images