JP6594167B2 - Inkjet recording apparatus, recording method, and program - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that performs recording by ejecting ink onto a recording medium such as printing paper, and in particular, a full multi-head ink jet recording apparatus in which a plurality of recording heads each having a predetermined nozzle array are connected, a recording method, and the like. It is about the program.

  As one type of ink jet recording apparatus that performs recording by discharging ink from a recording head, a line head type ink jet recording apparatus is known. The line head type ink jet recording apparatus has a recording head in which ejection openings are arranged in a direction intersecting with a conveyance direction of a recording medium (printing paper). Then, while transporting the recording medium in a direction intersecting with the direction in which the ejection port array extends, recording is performed by ejecting ink from the ejection port of the recording head to the recording medium. In this line head type ink jet recording apparatus, ink for one line or a plurality of lines is ejected all at once from the recording head, and these are continuously performed while transporting the recording medium, so that the recording speed is high. There is an advantage.

  However, in the manufacturing stage of a long recording head used in such a line head type ink jet recording apparatus, it is technically and costly to arrange a large number of nozzles in a single row at a high density on a single substrate. With many difficulties. Therefore, in a line head type ink jet recording apparatus, a continuous line head (hereinafter also referred to as “full multi head”) is used. This full multi-head is configured as a line head that is elongated by connecting a plurality of relatively short short recording heads in which a large number of nozzles are arranged at high density in a staggered manner.

  In such an ink jet recording apparatus in which a plurality of short recording heads are connected, there is a problem of deterioration in image quality due to white lines or black lines, which occurs in a part of an image corresponding to the connecting part of the recording heads. Patent Document 1 describes a method for suppressing such image degradation of white stripes or black stripes. In the method described in Patent Document 1, a plurality of recording heads are connected so as to overlap each other. Then, in the overlap region, the density (recording duty) of the recording dots corresponding to one recording head is gradually decreased, and the density of the recording dots corresponding to the other recording head is gradually decreased so as to compensate for the decrease. Will be increased.

  On the other hand, in the ink jet recording apparatus, there is a problem of so-called skew feeding in which the recording medium is shifted in an oblique direction from the original conveyance direction. For this reason, in recent years, several proposals regarding the skew correction technique have been made (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 5-57965 JP 2008-105347 A

  Accordingly, the present invention provides a full multi-head ink jet capable of forming an image with no inclination on a recording medium while suppressing deterioration in image quality and without stopping the printing process even when the recording medium is skewed. A recording apparatus, a recording method, and a program are provided.

  An inkjet recording apparatus according to the present invention is a full-head inkjet recording apparatus in which a plurality of recording heads each having a predetermined nozzle row are overlapped with each other and connected to each other. And recording data for recording an image according to a skew correction angle that is detected by a skew correction unit that detects a joint correction unit that performs joint correction that makes a joint between recording heads inconspicuous. And skew correction means for performing skew correction on the recording data so that the image is not inclined with respect to the medium, and the width of the overlap area is set to a maximum skew angle allowed in the conveyance of the recording medium. The width is determined based on the width of the connection correction area to be subjected to the connection correction.

  According to the present invention, in a full multi-head ink jet recording apparatus, an image having no inclination is recorded on a recording medium while suppressing deterioration in image quality and without stopping the printing process even when the recording medium is skewed. Can be formed.

It is a figure which shows an example of a structure of the inkjet recording device which concerns on a 1st Example. It is a figure explaining the detection method of a skew angle. It is the figure which represented typically the processing area of each processor which concerns on a 1st Example. It is a figure which shows a mode that the process area | region of each processor inclined by skew conveyance. It is a figure explaining the derivation | leading-out method of the shift amount of recording data. It is a sequence diagram explaining the flow of the process in the recording data correction part of a 1st Example. 6 is a flowchart showing a flow of processing for performing skew correction recording in real time according to skew feeding of printing paper according to the first embodiment. It is a block diagram which shows the structure of the inkjet recording device which concerns on a 2nd Example. It is the figure which represented typically the processing area of each processor which concerns on a 2nd Example. It is a figure for demonstrating the skew correction of a front | former stage. It is a figure for demonstrating back skew correction. 12 is a flowchart showing a flow of processing for performing skew correction recording in real time according to skew feeding of printing paper according to a second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

[Example 1]
In this embodiment, a full multi-head ink jet recording apparatus in which a plurality of recording heads each having a predetermined nozzle array are connected will be described as an example. In this embodiment, it is assumed that four processors corresponding to the four recording heads are provided, and each processor controls recording data in a predetermined area in which the printing area is divided into strips. However, the number of recording heads and processors is not limited to this, and the number may be less than four or more than four.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings.

(Configuration of inkjet recording apparatus)
FIG. 1 is a diagram illustrating an example of the configuration of the ink jet recording apparatus according to the first embodiment. The ink jet recording apparatus 100 includes a control unit 110, a recording data correction unit 120, a full multihead unit 130, and a skew detection unit 140. The full multi-head unit 130 has a configuration in which four recording heads (first to fourth recording heads) overlap each other with a certain predetermined width and are arranged in a staggered manner. The overlapping of the recording heads makes the joints between the recording heads inconspicuous at the time of printing, that is, prevents specific image quality degradation such as white stripes and black stripes caused by the joints between the recording heads. This is to perform “joint correction”.

  Further, the overlap area between the print heads in the ink jet printing apparatus 100 has such a width that the print data corresponding to the linkage correction area (the area to be subjected to the linkage correction) can be accommodated in the overlap area even after the skew correction. It is characterized by being. That is, in this embodiment, a margin for skew correction is secured by setting the width of the overlap area between the print heads to be larger than the width of the connection correction area. Further, in the following description using the drawings, expressions such as left, right, left side, right side, left end, right end, etc. are used, which mean left, right, left side, right side, left end, right end, etc. in each figure. .

  Hereinafter, each part in FIG. 1 will be described.

  When the printing paper is skewed in the transport direction, the skew detection unit 140 detects the skew and detects the skew angle. The skew detection unit 140 is controlled by any one of the first to fourth processors described above or under an independent processor (not shown). In the present embodiment, description will be made assuming that the operation is under the control of the first processor. Information on the detected skew angle is sent to the first to fourth shift processing units described above. FIG. 2 is a diagram for explaining a skew angle detection method. Sensors (701L, 701R) such as photodiodes for detecting both ends of the printing paper 700 are disposed at predetermined positions on the conveyance path. The predetermined position may be a fixed position according to the size of printing paper to be used, or may be variable by providing it at both ends of a movable conveyance guide. Then, a time difference T in which the left and right paper edges pass through the sensor is obtained from the sensor waveform obtained from the sensor 701L and the sensor waveform obtained from the sensor 701R, and thereby the skew angle can be obtained. The skew angle detection method described here is merely an example, and the present invention is not limited to this. Other methods may be used.

  The control unit 110 includes first to fourth processors and first to fourth memories corresponding to four recording heads (first to fourth recording heads), respectively. Further, the control unit 110 includes one skew detection unit 140. Similarly, the recording data correction unit 120 corresponds to the first to fourth recording heads, respectively, the first to fourth connection processing units, the first to fourth shift processing units, the first to fourth nozzle buffers, There are first to fourth head data transmission units. In the accompanying drawings including FIG. 1, the first to fourth recording heads are indicated by recording head # 1, recording head # 2, recording head # 3, and recording head # 4, respectively. The first to fourth processors are indicated by processor # 1, processor # 2, processor # 3, and processor # 4, respectively. The first to fourth memories are indicated by memory # 1, memory # 2, memory # 3, and memory # 4, respectively. The first to fourth connection processing units are respectively indicated by a connection processing unit # 1, a connection processing unit # 2, a connection processing unit # 3, and a connection processing unit # 4. The first to fourth shift processing units are indicated by shift processing unit # 1, shift processing unit # 2, shift processing unit # 3, and shift processing unit # 4, respectively. The first to fourth nozzle buffers are indicated by nozzle buffer # 1, nozzle buffer # 2, nozzle buffer # 3, and nozzle buffer # 4, respectively. The first to fourth head data sending units are respectively indicated by a head data sending unit # 1, a head data sending unit # 2, a head data sending unit # 3, and a head data sending unit # 4.

  Here, the processing area in charge of the first to fourth processors (hereinafter referred to as the processing areas of the first to fourth processors) will be described. Each processing area is set by the control unit 110. FIG. 3 is a diagram schematically illustrating the processing area of each processor according to the first embodiment. In FIG. 3, an area indicated by a double-headed arrow 201 (processing area 201) indicates a processing area of the first processor. An area indicated by a double-headed arrow 202 (processing area 202) indicates a processing area of the second processor. An area indicated by a double-headed arrow 203 (processing area 203) indicates a processing area of the third processor. An area indicated by a double arrow 204 (processing area 204) indicates a processing area of the fourth processor. In FIG. 3, the area indicated by a double-headed arrow 250 (a joint correction area 250) is at least required for performing joint correction for preventing image quality deterioration at the joint between the first recording head and the second recording head. Represents an area. An area indicated by a double-headed arrow 251 (a connection correction area 251) indicates a connection correction area between the second recording head and the third recording head. An area indicated by a double-headed arrow 252 (a connection correction area 252) indicates a connection correction area between the third recording head and the fourth recording head. In FIG. 3, an area indicated by a double arrow 260 (overlap area 260) indicates an overlap area between the first recording head and the second recording head. An area indicated by a double-headed arrow 261 (overlap area 261) indicates an overlap area between the second recording head and the third recording head. A region (overlap region 262) indicated by a double-headed arrow 262 indicates an overlap region between the third recording head and the fourth recording head.

  In this embodiment, as shown in FIG. 3, the width of the overlap area between the processors (the width in the horizontal direction in FIG. 3) and the width of the corresponding connection correction area (the width in the horizontal direction in FIG. 3) are the same. The processing area of each processor is set so that In this embodiment, the width of the joint correction areas 250 to 252 is set to a minimum necessary width to prevent image quality deterioration at the joint between the print heads. Further, as shown in FIG. 3, the print heads are connected and arranged so that the width of the overlap area between the print heads (the width in the left-right direction in FIG. 3) is larger than the width of the connection correction area. Here, the minimum required width to prevent image quality deterioration at the joint between the recording heads is, for example, a width corresponding to the width of the white stripe or black stripe caused by the joint between the recording heads.

  Hereinafter, a group of configurations corresponding to the first recording head (that is, a first processor, a first memory, a first connection processing unit, a first shift processing unit, a first nozzle buffer, a first head data sending unit) will be taken as an example. The operation of each unit will be described.

  In the first area (processing area 201) among the areas (here, the areas divided into four strips) divided in the direction intersecting the transport direction, the first processor Control and manage the data to be recorded. The first processor temporarily stores the recording data in the first memory, reads the recording data from the first memory in units of lines, and sends the recording data to the recording data correction unit 120 in the next stage. At this time, the width of the recording data in line units is assumed to be equal to the width of the processing area.

  The first splicing processing unit performs a splicing process on the recording data sent from the first processor in units of lines. Here, the joining process refers to a process of determining which of the first recording head and the second recording head ejects ink in the joining correction area 250 shown in FIG. The first joint processing unit performs the joint correction as the joint process. Note that the specific processing contents of the connection correction are not directly related to the present invention, and thus the description thereof is omitted here.

  The first shift processing unit is configured to determine the direction of the nozzle row of the recording data based on the coordinates of the recording data in units of lines connected by the first connection processing unit and the skew angle information received from the skew detection unit 140. And the shift amount in the transport direction are derived respectively. Details of the method of deriving the shift amount will be described later. Further, the first shift processing unit converts the derived shift amount into an address value in the first nozzle buffer. The first shift processing unit offsets the converted address value to the address value of the original recording data, that is, the recording data for one line input from the first memory. The recording data (corrected recording data) generated in this way is written to the first nozzle buffer in line units.

  The first nozzle data buffer is a memory for temporarily storing print data immediately before being sent to the first print head, and its width is assumed to be equal to the width of the first print head. Details of the nozzle data buffer will be described later.

  The first head data sending unit reads the print data in line units from the first nozzle buffer and sends the data to the first print head.

  The same relationship applies to the group of configurations corresponding to the second to fourth recording heads.

  FIG. 4 is a diagram illustrating a state in which the processing area of each processor is tilted by the skew feeding.

  The processing area 201 ′ of the first processor shown in FIG. 4 is the processing area 201 of the first processor that is inclined by the skew feeding. The processing area 202 ′ of the second processor is the processing area 202 of the second processor that is inclined by the skew feeding. The processing area 203 ′ of the third processor is the processing area 203 of the third processor that is inclined by the skew feeding. The processing area 204 ′ of the fourth processor is the processing area 204 of the fourth processor that is inclined by the skew feeding. The connection correction area 250 ′ is a connection correction area 250 that is inclined by the skew feeding. The connection correction area 251 ′ is a connection correction area 251 that is inclined by the skew feeding. The connection correction area 252 ′ is a connection correction area 252 that is inclined by the oblique conveyance.

  If the corner A and the corner F of the joint correction area 250 ′ are within the overlap area 260 of the first recording head and the second recording head, the first processor performs skew correction in the processing area 201 ′. And decide. An angle 310 shown in FIG. 4 is a maximum allowable skew angle. Here, the maximum allowable skew angle is the maximum allowable skew that can be transported in the transport mechanism (not shown) of the inkjet recording apparatus 100 without clogging the transport mechanism even if the printing paper is skewed. Indicates the skew angle. Depends on the actual transport system mechanical configuration (for example, how much play is in the transport path), for example, by performing a test transport in advance and determining the transportable angle without causing a paper jam Is done. Thus, the overlap area 260 of the first recording head and the second recording head is determined based on the maximum allowable skew angle 310 and the width of the connection correction area 250.

  Similarly, if the corners B and G of the joint correction area 251 ′ are within the overlap area 261 of the second recording head and the third recording head, the second processor corrects the skew correction in the processing area 202 ′. Decide to do. That is, the overlap area 261 is also determined based on the maximum allowable skew angle 310 and the width of the connection correction area 251.

  Similarly, if the corners C and H of the joint correction area 252 ′ are within the overlap area 262 of the third recording head and the fourth recording head, the third processor corrects the skew feeding correction in the processing area 203 ′. Decide to do. That is, the overlap area 262 is also determined based on the maximum allowable skew angle 310 and the width of the connection correction area 252.

  Next, a method for deriving the shift amount during skew correction will be described. The shift amount is derived from the coordinates of the recording data in line units that are connected by the connection processing unit (first to fourth connection processing units) in the shift processing unit (first to fourth shift processing units), and the slant. This is based on the skew angle information sent from the row detection unit 140. In the derivation method described below, since a very short processing time is required for the printing process, it is possible to perform skew correction in real time without stopping the printing process. FIG. 5 is a diagram for explaining a method for deriving the shift amount of the recording data. In FIG. 5, a solid-line rectangle 500 indicates a printing sheet (hereinafter referred to as a normal conveyance sheet) in a straight state that has been normally conveyed without being skewed. A broken-line rectangle 510 indicates a print sheet (skew transport sheet) that is transported obliquely and inclined obliquely. Assuming that the angle during the skew conveyance is θ, the skew conveyance paper 510 is rotated counterclockwise at an angle θ around the center point of the normal conveyance paper 500. Therefore, the recording data that should normally be recorded on the normal conveyance sheet 500 is recorded at a position rotated counterclockwise at an angle θ on the skew conveyance sheet 510. That is, if the recording data on the normal transport paper 500 is A, and the coordinates of the recording data A are (x, y), the recording data A is recorded as recording data A ′ by being transported at an oblique angle θ. It is recorded at the position of coordinates (x ′, y ′). The coordinates (x ′, y ′) of the recording data A ′ at this time can be expressed by the following formula (1).

When the above equation (1) is solved, the coordinates (x ′, y ′) of the recording data A ′ are as follows.
x '= x * cosθ-y * sinθ
y '= x * sinθ + y * cosθ

The shift amount of the recording data can be obtained from the difference between the original coordinate and the new coordinate in each of the nozzle row direction and the transport direction, and can be expressed by the equations (2) and (3), respectively.
Nozzle row direction shift amount = x'-x (2)
Shift amount in the transport direction = y'-y (3)

  Thus, each of the first to fourth shift processing units determines the shift amount of the print data in the nozzle row direction based on the coordinates of the print data and the skew angle information received from the skew detection unit 140. Each shift amount in the transport direction is derived. The derived shift amount is converted into an address value in the nozzle buffer, and the converted address value is offset added to the address value of the original print data.

FIG. 6 is a sequence diagram for explaining the flow of processing in the recording data correction unit 120 of the first embodiment. Here, a case where skew correction is performed on the assumption that recording data of 4 dots × 4 dots is recorded by a recording head having eight nozzles will be described as an example. The width of the memory for storing the recording data is assumed to be equal to the width of the processing area of the processor. The width of the nozzle buffer is assumed to be equal to the width of the recording head. Further, it is assumed that the nozzle buffer has a length in the vertical direction (vertical width) that can accommodate the maximum skew. If one of the ink droplets ejected from the nozzles of the recording head is 1 dot, the recording data of 4 dots × 4 dots is stored in the memory. As shown in FIG. 6, in the recording data correction unit 120, processing proceeds in units of lines in the following order 1) to 4).
1) Recording data (line data) for one line is input from the memory 2) Execute the splicing process for the input line data 3) Deriving the shift amount from the line data after the splicing process 4) Calculate the derived shift amount The reflected recording data (corrected recording data) for one line is stored in the nozzle buffer. 5) The recording data for one line is sent to the recording head. Hereinafter, each process in the first to fourth lines will be described in time series.

<First line>
First, the connection processing unit reads data (00, 01, 02, 03) of the first line from the memory. Actually, at this time, the linkage processing unit executes the linkage processing on the data (00, 01, 02, 03). However, in FIG. 6, the description of the linkage processing is omitted for the sake of simplicity. ing.

Next, the shift processing unit determines the coordinates of each dot data in the read line data (00, 01, 02, 03) (actually, the line data after the connection process) and the skew detection unit 140. From the received skew angle information, the shift amount in the nozzle row direction and the shift amount in the transport direction are respectively derived. Here, the derived shift amount is expressed as (shift amount in the nozzle row direction, shift amount in the transport direction). Then, the shift amount of each dot data is as follows (here, for convenience of explanation, the shift amount in the nozzle row direction is set to zero).
Shift amount of dot data “00”: (0, 0)
Shift amount of dot data “01”: (0, +1)
Shift amount of dot data “02”: (0, +2)
Shift amount of dot data “03”: (0, +3)

  Then, the shift processing unit converts the derived shift amount into an address value in the nozzle buffer. Here, it is assumed that the address value changes by “1” when the shift amount is “1”. The shift processing unit offsets the converted address value to the address value of each original dot data, and writes each dot data in the nozzle buffer. For example, for dot data “01”, there is no change in the shift amount in the nozzle row direction, but since the shift amount in the transport direction is “+1”, an address value “1” is offset in the transport direction. Similarly, for dot data “02”, there is no change in the shift amount in the nozzle row direction, but since the shift amount in the transport direction is “+2”, an address value “2” is offset in the transport direction. . Similarly, for dot data “03”, there is no change in the shift amount in the nozzle row direction, but since the shift amount in the transport direction is “+3”, the address value 3 is offset in the transport direction. In FIG. 6, each dot data reflecting the shift amount is indicated by “00 ′, 01 ′, 02 ′, 03 ′”. As a result of the shift amount being reflected in the line data, the nozzle buffer stores one line of print data (corrected print data) whose address value is shifted by one in the transport direction according to the shift amount in the transport direction. It will be. Then, the print data is read from the nozzle buffer in line units by the head data sending unit, and data (head data) 601 for one line is sent to the print head.

<Second line>
Next, data (10, 11, 12, 13) for the second line is read from the memory. Then, the shift processing unit calculates the shift amount in the nozzle row direction for the read line data (10, 11, 12, 13) (actually, the line data after the joining process) in the same manner as the first line. Each shift amount in the transport direction is derived. The shift amount of each dot data is as follows.
Shift amount of dot data “10”: (0,0)
Shift amount of dot data “11”: (0, + 1)
Shift amount of dot data “12”: (0, + 2)
Shift amount of dot data “13”: (0, + 3)

  Then, the shift processing unit converts the derived shift amount into an address value in the nozzle buffer, adds the converted address value to the address value of each original dot data, and writes each dot data to the nozzle buffer. In FIG. 6, each dot data reflecting the shift amount is indicated by “10 ′, 11 ′, 12 ′, 13 ′”. Then, the print data is read from the nozzle buffer in units of lines by the head data sending unit, and data (head data) 602 for one line is sent to the print head.

<3rd line>
Next, the data (20, 21, 22, 23) on the third line is read from the memory. Then, the shift processing unit shifts the read line data (20, 21, 22, 23) (actually, the line data after the joining process) in the nozzle row direction as in the first and second lines. The amount and the shift amount in the transport direction are derived respectively. The shift amount of each dot data is as follows.
Shift amount of dot data “20”: (0,0)
Shift amount of dot data “21”: (0, + 1)
Shift amount of dot data “22”: (0, + 2)
Shift amount of dot data “23”: (0, + 3)

  Then, the shift processing unit converts the derived shift amount into an address value in the nozzle buffer, adds the converted address value to the address value of each original dot data, and writes each dot data to the nozzle buffer. In FIG. 6, each dot data reflecting the shift amount is indicated by “20 ′, 21 ′, 22 ′, 23 ′”. Then, the print data is read from the nozzle buffer in line units by the head data sending unit, and data (head data) 603 for one line is sent to the print head.

<4th line>
Next, data (30, 31, 32, 33) on the fourth line is read from the memory. Then, the shift processing unit shifts the read line data (30, 31, 32, 33) (actually, the line data after the joining process) in the nozzle row direction as in the first to third lines. The amount and the shift amount in the transport direction are derived respectively. The shift amount of each dot data is as follows.
Shift amount of dot data “30”: (0,0)
Shift amount of dot data “31”: (0, + 1)
Shift amount of dot data “32”: (0, + 2)
Shift amount of dot data “33”: (0, + 3)

  Then, the shift processing unit converts the derived shift amount into an address value in the nozzle buffer, adds the converted address value to the address value of each original dot data, and writes each dot data to the nozzle buffer. In FIG. 6, each dot data reflecting the shift amount is indicated by "30 ', 31', 32 ', 33'". Then, the print data is read from the nozzle buffer in line units by the head data sending unit, and data (head data) 604 for one line is sent to the print head.

  After this, since there is no print data remaining in the memory, the line data reading from the memory and the shift amount derivation process are skipped, and the dot data remaining in the nozzle buffer are sequentially sent to the print head line by line. . Then, when all the dot data in the nozzle buffer has been sent to the recording head, the process ends.

  FIG. 7 is a flowchart showing a flow of processing for performing skew correction recording in real time in accordance with skew feeding of printing paper according to the first embodiment. The following series of processing is executed based on a program stored in a ROM (not shown) or the like. Each processor executes the processing of the following steps for the recording data in the processing area allocated to itself. The skew detection unit 140 is assumed to be placed under the control of any one of the first to fourth processors.

  In step S701, the edge of the printing paper is detected by the sensor of the skew detection unit 140.

  In step S702, the presence or absence of skew is determined based on the time difference when both ends of the printing paper pass the sensor. In order to determine whether or not the image is skewed, a threshold value determined in advance by test conveyance using printing paper actually used may be used. If it is determined that the image is skewed, the processor proceeds to the process of step S703. On the other hand, if it is determined that the skew is not performed, the processor proceeds to the process of step S711 to execute a normal printing process without skew correction. When it is determined that there is no skew feeding, input of recording data for one line (step S711), execution of a joining process for the recording data (step S712), and transmission of the recording data after the joining process to the recording head (Step S713) is repeated until completion for all the lines (Step S714).

  In step S703, the detected skew angle is obtained by the method described above. Information on the obtained skew angle is sent to each shift processing unit. The following steps will be described by taking each unit under the control of the first processor as an example.

  In step S704, based on the skew angle information, it is determined whether or not the detected skew angle is within the above-described maximum allowable skew angle range. The determination may be performed by the first processor or the first shift processing unit. If the detected skew angle is within the range of the maximum allowable skew angle, the first processor proceeds to the process of step S705. On the other hand, if the detected skew angle exceeds the range of the maximum allowable skew angle, the first processor proceeds to the process of step S715 to perform error processing. That is, in step S715, the user is notified that the printing paper is tilted beyond the allowable range by, for example, displaying an error message on a display unit (not shown). In subsequent step S716, a printing paper discharge process (such as a stop of conveyance if the printing paper is discharged as it is or is skewed so as not to be discharged) is executed.

  In step S705, recording data is input line by line from the first memory.

  In step S706, the connection process is executed on the recording data (line data) for one line input from the first memory in the first connection processing unit.

  In step S707, the first shift processing unit uses the nozzles of the line data based on the coordinates of the recording data (line data) for one line after the joining process and the skew angle information from the skew detection unit 140. The shift amount in the row direction and the shift amount in the transport direction are respectively derived.

  In step S708, one line of print data (corrected print data) reflecting the derived shift amount is stored in the first nozzle buffer.

  In step S709, print data is read from the first nozzle buffer in line units and sent to the first print head. In the first recording head, an image according to the input recording data is formed on the recording medium.

  In step S710, it is determined whether or not processing for all lines has been completed. If the processing for all lines has been completed, the first processor finishes this processing. On the other hand, if there is an unprocessed line, the first processor returns to the process of step S705. The next line is then processed.

  The above is the content of the processing according to the present embodiment for performing recording while performing skew correction in real time according to the skew of the printing paper.

  In other processors that are not under the control of the skew detection unit 140, the determination results in steps S702 and S704 are received from the processor that controls the skew detection unit 140, and the recording data of each processing region is received. The process after step S705 is executed as a target. If the skew detection unit 140 is controlled under a processor independent of the first to fourth processors, the processes from steps S701 to S704 are performed separately. The processing results are received by the first to fourth processors, and the processing from step S705 onward is executed for the recording data in each processing area.

  In step S704, each processor receives the determination result of the other processor, calculates the logical product (AND) of its own determination result and the determination result of the other processor, and in accordance with the calculation result, You may make it transfer to a step (step S705 or step S715).

  As described above, the ink jet recording apparatus of the present embodiment includes a plurality of processors corresponding to one to one (or a plurality of one to one) in a plurality of recording heads constituting a full multi head, Control and manage recording data in a predetermined area divided into strips. Further, in the present embodiment, the width of the overlap area between the print heads is adjusted after the skew correction (specifically, the skew correction according to the maximum allowable skew angle) of the print data corresponding to the joint correction area. Is also set to a width that fits within the overlap area. With such a configuration, it is possible to perform skew correction in consideration of joint correction. Specifically, since the recording data subjected to the connection correction fits in the overlap area between the recording heads even after the skew correction, the recording data subjected to the connection correction can be appropriately recorded on the recording medium. . Therefore, according to the present embodiment, it is possible to obtain a straight image on the printing paper while suppressing deterioration of image quality at the joint of the recording head.

  In addition, the skew correction (record data shift control) in this embodiment is completed in a very short time with respect to the printing process, and thus does not affect the printing process in terms of time. Therefore, according to the present embodiment, real-time skew correction can be realized, and a straight image can be obtained on the printing paper without stopping the printing process.

[Example 2]
In the first embodiment, an example in which a margin for skew correction is provided by making the width of the overlap area between the recording heads larger than the width of the connection correction area has been described. The second embodiment shows an example in which skew correction is performed in two stages by providing a margin for skew correction in both the overlap area between the print heads and the overlap area between the processing areas of the processor. .

  Similarly, in the second embodiment, four print heads each having a predetermined nozzle array are connected to each other while four are connected together, and four processors corresponding to the four print heads are each formed in a strip shape. Control and manage recorded data.

  The second embodiment of the present invention will be described below.

  FIG. 8 is a block diagram illustrating a configuration of an inkjet recording apparatus 200 according to the second embodiment.

  Below, it demonstrates centering on difference with a 1st Example.

  The ink jet recording apparatus 200 includes a recording data correction unit 220 instead of the recording data correction unit 120.

  The recording data correction unit 220 includes first to fourth pre-shift processing units, first to fourth intermediate data buffers, first to fourth connection processing units, first to fourth recording units corresponding to the first to fourth recording heads, respectively. There are first to fourth rear shift processing units, first to fourth nozzle buffers, and first to fourth head data sending units.

  The first to fourth pre-shift processing units perform the pre-stage (first stage) skew correction among the above-described two stages of skew correction.

  The first to fourth intermediate data buffers are memories for temporarily storing the recording data that has been subjected to the first-stage skew correction by the first to fourth previous-stage shift processing units.

  The first to fourth rear-stage shift processing units perform the second-stage skew correction among the two-stage skew correction described above.

  In FIG. 8, the first to fourth pre-shift processing units are respectively indicated by pre-shift processing unit # 1, pre-shift processing unit # 2, pre-shift processing unit # 3, and pre-shift processing unit # 4. The first to fourth intermediate data buffers are respectively indicated by an intermediate data buffer # 1, an intermediate data buffer # 2, an intermediate data buffer # 3, and an intermediate data buffer # 4. The first to fourth rear shift processing units are respectively indicated by a rear shift processing unit # 1, a rear shift processing unit # 2, a rear shift processing unit # 3, and a rear shift processing unit # 4.

  First, processing areas of the first to fourth processors according to the present embodiment will be described. Each processing area is set by the control unit 110. FIG. 9 is a diagram schematically illustrating the processing area of each processor according to the second embodiment. In FIG. 9, an area indicated by a double arrow 901 (processing area 901) indicates the processing area of the first processor. An area (processing area 902) indicated by a double-pointed arrow 902 indicates a processing area of the second processor. An area (processing area 903) indicated by a double-headed arrow 903 indicates a processing area of the third processor. An area indicated by a double arrow 904 (processing area 904) indicates a processing area of the fourth processor. In FIG. 9, an area indicated by a double-headed arrow 950 (a joining correction area 950) indicates a joining correction area between the first recording head and the second recording head. As in the first embodiment, the width of the joint correction area is set to a minimum necessary width to prevent image quality deterioration at the joint between the print heads. This is the minimum area required to perform the connection correction. An area indicated by a double-pointed arrow 951 (a connection correction area 951) indicates a connection correction area between the second recording head and the third recording head. An area indicated by a double-pointed arrow 952 (a connection correction area 952) indicates a connection correction area between the third recording head and the fourth recording head. In FIG. 9, an area indicated by a double-headed arrow 960 (overlap area 960) indicates an overlap area between the first recording head and the second recording head. An area indicated by a double-headed arrow 961 (overlap area 961) indicates an overlap area between the second recording head and the third recording head. An area indicated by a double-headed arrow 962 (overlap area 962) indicates an overlap area between the third recording head and the fourth recording head. In this embodiment, as shown in FIG. 9, similarly to the first embodiment, the widths of the overlap areas 960, 961, 962 between the heads (widths in the left-right direction in FIG. 9) correspond to the respective connections. The width of each head is set so as to be wider than the width of the correction area (connection correction areas 950, 951, 952) (the width in the left-right direction in FIG. 9). Furthermore, in this embodiment, as shown in FIG. 9, the width of the overlap area between the processors (the width in the horizontal direction in FIG. 9) and the width of the overlap area between the corresponding heads are the same. The processing area of each processor is set.

  Hereinafter, a group of configurations corresponding to the first recording head (that is, the first processor, the first memory, the first front-stage shift processing unit, the first intermediate data buffer, the first connection processing unit, the first rear-stage shift processing unit, the first The operation of each unit will be described by taking a 1 nozzle buffer and a first head data sending unit) as an example.

  As in the first embodiment, the first processor controls and manages data recorded by the first recording head in the first area (processing area 901) obtained by dividing the print area into four strips. . Further, as shown in FIG. 9, the first processor sets the inside of the processing area 901 to the width of the first recording head. The connection correction area 950 is a part of an overlap area between the processing area of the first processor and the processing area of the second processor. The first processor performs joint correction in the joint correction area 950.

  The first pre-shift processing unit performs the pre-stage skew correction, and based on the coordinates of the recording data sent in units of lines from the first processor and the skew angle notified from the skew detection unit 140. Then, the preceding shift amount in the nozzle row direction of the recording data and the preceding shift amount in the transport direction are derived. The method for deriving the preceding shift amount is the same as the shift amount deriving method shown in FIG. FIG. 10 is a diagram for explaining the previous skew correction. A rectangular area indicated by a broken line in FIG. 10 represents a processing area of each processor that has become slanted as the printing paper is conveyed obliquely. A maximum allowable front-stage skew angle 930 illustrated in FIG. 10 represents a maximum angle at which the front-stage skew correction can be performed.

  The skew correction in the preceding stage is skew correction performed using a margin generated by setting an overlap area between the processing areas of the processor wider than the connection correction area.

  Further, the first pre-stage shift processing unit converts the derived pre-stage shift amount into an address value in the first intermediate data buffer, and converts the converted address into the original recording data, that is, recording data for one line input from the first memory. The offset is added to the addresses of, and written to the first intermediate data buffer.

  The first connection processing unit performs connection processing on the recording data in units of lines read from the first intermediate data buffer. The connecting process in this embodiment is the same as that in the first embodiment. That is, the first joint processing unit performs a process of determining which of the first print head and the second print head ejects ink in the joint correction area 950 shown in FIG.

  The first rear-stage shift processing unit performs rear-stage skew correction. The subsequent skew correction is executed when the skew angle notified from the skew detection unit 140 is larger than the maximum allowable front skew angle 930. Therefore, when the skew angle notified from the skew detection unit 140 is equal to or less than the maximum allowable preceding skew angle 930, the first subsequent shift processing unit does not perform the subsequent skew correction. FIG. 11 is a diagram for explaining the subsequent skew correction. The maximum allowable rear-stage skew angle 940 shown in FIG. 11 corresponds to the maximum allowable skew angle 310 in the first embodiment. The maximum allowable rear-stage skew angle 940 that represents the maximum angle at which the subsequent stage skew correction is possible.

  The first rear-stage shift processing unit divides the maximum allowable front-stage skew angle 930 from the coordinates of the recording data in units of lines connected by the first joint processing unit and the skew angle notified from the skew detection unit 140. Based on the angle, the subsequent shift amount of the print data in the nozzle row direction and the subsequent shift amount in the transport direction are calculated. The method of deriving the subsequent shift amount is the same as the method of deriving the shift amount shown in FIG. The subsequent skew correction is skew correction performed using a margin generated by setting the overlap area between the print heads wider than the connection correction area.

  Since the configuration of the first nozzle data buffer and the operation of the first head data sending unit are the same as those in the first embodiment, description thereof will be omitted.

  The same relationship applies to the group of configurations corresponding to the second to fourth recording heads.

  Here, operations of the first to fourth front shift processing units and the first to fourth rear shift processing units will be described.

  The first front-stage shift processing unit executes the front-stage skew correction when it is determined that the skew angle notified from the skew detection unit 140 is equal to or less than the maximum allowable front-stage skew angle. As shown in FIG. 10, the maximum allowable preceding stage skew angle used for determination by the first front stage shift processing unit is a corner L of the processing area 901 (processing area 901 ′ shown in FIG. 10) that is inclined by the skew feeding. Is the skew angle when it overlaps the right end of the connection correction area 950.

  When the shift position of the recording data derived by the first pre-shift processing unit enters the processor discard area (rectangular area indicated by the broken horizontal line in FIG. 10) 911 on the right side of the connection correction area 950, the recording data is It becomes discarded data. For the recording data that has been discarded, the first pre-shift processing unit does not write to the first intermediate data buffer.

  Similarly, the second pre-stage shift processing unit performs the pre-stage skew correction when it is determined that the skew angle notified from the skew detection unit 140 is equal to or smaller than the maximum allowable front-stage skew angle. As shown in FIG. 10, the maximum allowable preceding-stage skew angle used by the second preceding-stage shift processing unit for the determination is the corner I of the processing area 902 (processing area 902 ′ shown in FIG. 10) that is inclined by the skew feeding. Is the smaller of the skew angle when overlapping the left end of the joint correction area 950 and the skew angle when corner M of the processing area 902 'overlaps the right end of the joint correction area 951. is there.

  The shift positions of the recording data derived by the second pre-stage shift processing unit are the processor discard areas (areas indicated by the solid diagonal lines in FIG. 10) 912 and 913 on the left side of the joint correction area 950 and the right side of the joint correction area 951. When entered, this recorded data becomes discarded data. For the recording data that has been discarded, the second pre-stage shift processing unit does not write to the second intermediate data buffer.

  Similarly, if the third pre-shift processing unit determines that the skew angle notified from the skew detection unit 140 is less than or equal to the maximum allowable front skew angle, the third pre-shift processing unit performs the previous skew correction. As shown in FIG. 10, the maximum allowable preceding-stage skew angle used for the determination by the third preceding-stage shift processing unit is a corner portion J of the processing area 903 (processing area 903 ′ shown in FIG. 10) that is inclined by the skew feeding. Is the smaller of the skew angle when overlapping the left end of the connection correction area 951 and the skew angle when the corner N of the processing area 903 ′ overlaps the right end of the connection correction area 952. is there.

  The processor discard areas (areas indicated by the hatched lines in FIG. 10) 914 and 915 where the shift positions of the recording data derived by the third pre-shift processing section are on the left side of the joint correction area 951 and on the right side of the joint correction area 952. When entered, this recorded data becomes discarded data. For the recording data that has been discarded, the third pre-shift processing unit does not write to the third intermediate data buffer.

  Similarly, if the fourth pre-shift processing unit determines that the skew angle notified from the skew detection unit 140 is less than or equal to the maximum allowable front skew angle, the fourth pre-shift processing unit performs the preceding skew correction. As shown in FIG. 10, the maximum allowable preceding stage skew angle used for the determination by the fourth front stage shift processing unit is a corner K of the processing area 904 (processing area 904 ′ shown in FIG. 10) that is inclined by the skew feeding. Is the skew angle when it overlaps the left end of the connection correction area 952.

  When the shift position of the recording data derived by the fourth pre-shift processing unit enters the processor discard area (area shown by a solid diagonal grid in FIG. 10) 916 on the left side of the connection correction area 952, this recording The data becomes discarded data. For the recording data that has been discarded, the fourth pre-shift processing unit does not write to the fourth intermediate data buffer.

  A rectangular area indicated by a broken line in FIG. 11 indicates the result of the subsequent skew correction performed on the recording data that has been subjected to the preceding skew correction illustrated in FIG.

  The first rear shift processing unit determines that the corner portion O of the post-skew correction post-skew correction region 950 (the connection correction region 950 ″ shown in FIG. 11) is within the range to the right end of the first recording head. In such a case, the skew correction in the subsequent stage is performed.

  Similarly, the second rear-stage shift processing unit has the corner R and the corner P of the joint correction area 950 (joint correction area 950 ″ shown in FIG. 11) after the subsequent skew correction at both ends of the second recording head. When it is determined that the value falls within the range, the subsequent skew correction is performed.

  Similarly, the third post-stage shift processing unit includes the corner S of the post-skew correction post-link correction area 951 (the connection correction area 951 ″ shown in FIG. 11) and the post-stage post-skew correction post-skew correction. If it is determined that the corner portion Q is within the range of both ends of the third recording head, the subsequent skew correction is performed.

  Similarly, in the fourth rear shift processing unit, the corner T of the joint correction area (joint correction area 952 ″ shown in FIG. 11) after the subsequent skew correction is within the range to the left end of the fourth recording head. If it is determined, the subsequent skew correction is performed.

  FIG. 12 is a flowchart showing a flow of processing for performing skew correction recording in real time according to the skew feeding of printing paper according to the second embodiment.

  Note that the processing in steps S1201 to S1205 and S1214 to S1219 is the same as the processing in steps S701 to S705 and S711 to S716 in the first embodiment, and thus the description thereof is omitted. In addition, the following steps will be described by taking each unit under the control of the first processor as an example.

  In step S1206, in the first pre-shift processing unit, based on the coordinates of the recording data (line data) for one line input from the first memory and the skew angle information from the skew detection unit 140, A preceding shift amount in the nozzle row direction and a preceding shift amount in the transport direction of the line data are respectively derived. When the skew angle indicated by the skew angle information from the skew detection unit 140 exceeds the maximum allowable preceding skew angle, the coordinates of the line data input from the first memory and the maximum allowable preceding stage Based on the skew angle, the preceding shift amount in the nozzle row direction and the preceding shift amount in the transport direction of the line data are respectively derived.

  In step S1207, the previous skew correction is executed. Specifically, the first preceding-stage shift processing unit converts the derived preceding-stage shift amount into an address value in the intermediate data buffer unit, and the converted address is the original recording data, that is, 1 input from the first memory. An offset is added to the address of the recording data for the line. The recording data (intermediate data) reflecting the preceding shift amount is stored in the intermediate data buffer unit.

  In step S1208, the intermediate data is read in line units from the intermediate data buffer unit, and a linkage process is executed on the read intermediate data for one line.

  In step S1209, based on a comparison between the skew angle indicated by the skew angle information from the skew detector 140 and the maximum allowable preceding-stage skew angle 930, it is determined whether or not there is an uncorrected skew angle. Is done. The uncorrected skew angle is an angle obtained by subtracting the maximum allowable preceding-stage skew angle from the skew angle detected by the skew detection unit 140. If there is no skew angle that has not been corrected (NO in step S1209), the first processor proceeds to the process in step S1212. If there is an uncorrected skew angle (YES in step S1209), the first processor moves to the process in step S1210.

  In step S1210, the first rear-stage shift processing unit 1 line worth based on the coordinates of the intermediate data for one line (specifically, the intermediate data after the linkage process) and the uncorrected skew angle. The subsequent shift amount of the intermediate data in the nozzle row direction and the subsequent shift amount in the transport direction are respectively derived.

  In step S1211, the subsequent skew correction is executed. Specifically, the first rear-stage shift processing unit converts the derived rear-stage shift amount into an address value in the nozzle data buffer unit, and uses the converted address as the original recording data, that is, intermediate data for one line (specifically Is added to the address of the intermediate data after the linkage process. The intermediate data reflecting the subsequent shift process is stored in the first nozzle data buffer unit.

  In step S <b> 1212, print data is read from the first nozzle data buffer unit in units of lines and sent to the first print head unit. In the first recording head, an image according to the input recording data is formed on the recording medium.

  In step S1213, it is determined whether processing for all lines has been completed. If the processing for all lines has been completed, the first processor finishes this processing. On the other hand, if there is an unprocessed line, the first processor returns to the process of step S1205. The next line is then processed.

  In step S1209, each processor receives the determination result of the other processor, calculates a logical product (AND) of its own determination result and the determination result of the other processor, and in accordance with the calculation result, You may make it transfer to a step (step S1210 or step S1212).

  As described above, in the second embodiment, in the ink jet recording apparatus in which four processors corresponding to the full multi-head control and manage the recording data in a strip shape, the overlap area between the processing areas of the processor and the recording are recorded. An example in which a margin for skew correction is provided in both overlap areas between the heads and two-stage skew correction is performed is shown. By performing such skew correction in real time, as in the first embodiment, it is possible to obtain a straight recording result on the printing paper without stopping the printing process.

(Other examples)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 100 Inkjet recording device 110 Control part 120 Recording data correction part 130 Full multi head part 140 Skew detection part

Claims (8)

In a full multi-head ink jet recording apparatus in which a plurality of recording heads each having a predetermined nozzle row are overlapped and connected to each other,
Skew detection means for detecting skew of the recording medium with respect to the transport direction;
Connection correction means for executing connection correction for making the connection between the recording heads inconspicuous with respect to recording data for recording an image;
Skew correction means for executing skew correction on the recording data so that the image does not tilt with respect to the recording medium according to the skew angle detected by the skew detection means;
The width of the overlap area is a width determined based on the maximum skew angle allowed in the conveyance of the recording medium and the width of the connection correction area to be subjected to the connection correction. Inkjet recording apparatus. The joint correction area is a part of the overlap area and having a predetermined width,
The joint correction is performed on a part of the recorded data corresponding to the joint correction area,
The width of the overlap area is such that even when the recording data is subjected to the skew correction according to the maximum skew angle, the part of the data subjected to the connection correction is recorded in the overlap area. The inkjet recording apparatus according to claim 1, which has a width as recorded on a medium. The skew correction means includes:
Shift processing for generating corrected recording data in which the positions of dots constituting the recording data are shifted in accordance with the skew angle detected by the skew detection means, and storing the generated corrected recording data in a buffer Shift processing means for performing
The inkjet recording apparatus according to claim 1, further comprising: a unit that reads the corrected recording data from the buffer and sends the corrected recording data to the recording head. The shift processing unit sets the shift amount in the nozzle row direction and the conveyance direction based on the coordinates of each dot in the recording data read in line units and the skew angle detected by the skew detection unit. The inkjet recording apparatus according to claim 3, wherein the corrected recording data is generated in units of lines by deriving in units. The skew correction means includes:
When the skew angle detected by the skew detection means is equal to or smaller than a predetermined angle, skew correction according to the skew angle is performed. When the skew angle is larger than the predetermined angle, the skew angle is corrected to the predetermined angle. First skew correction means for executing the corresponding skew correction on the recording data before the connection correction,
When the skew angle detected by the skew detection means is larger than the predetermined angle, skew correction according to an angle obtained by subtracting the predetermined angle from the detected skew angle is performed as the connection. The inkjet recording apparatus according to claim 1, further comprising: a second skew correcting unit that executes the corrected recording data. 6. The predetermined angle is determined based on a width of an overlap area of processing areas allocated to a plurality of processors corresponding to the full multi-head that controls the connection correction unit and the skew correction unit. 2. An ink jet recording apparatus according to 1. A recording method in a full multi-head ink jet recording apparatus in which a plurality of recording heads each having a predetermined nozzle row are overlapped with each other and connected,
A skew detection step for detecting skew of the recording medium relative to the transport direction;
A connection correction step for executing connection correction for making the connection between the recording heads inconspicuous with respect to recording data for recording an image;
A skew correction step of performing skew correction on the recording data so that the image does not tilt with respect to the recording medium according to the skew angle detected in the skew detection step,
The width of the overlap area is a width determined based on the maximum skew angle allowed in the conveyance of the recording medium and the width of the connection correction area to be subjected to the connection correction. Recording method.   A program for causing a computer to function as a part of the ink jet recording apparatus according to any one of claims 1 to 6.