JP7205223B2 - Image forming apparatus and image forming control method - Google Patents

Description

The present invention relates to an image forming apparatus and an image forming control method.

2. Description of the Related Art There is an image forming apparatus that ejects ink from a large number of nozzles and lands on a recording medium to record an image on the recording medium (including three-dimensional structure and film formation without color). In this image forming apparatus, the recording medium is relatively moved in a predetermined direction with respect to the nozzles in response to demands for higher speed and precision, and the printable width of the recording medium is covered in the width direction intersecting with the predetermined direction. There is a single-pass method that prints an image by arranging nozzles without scanning the nozzles.

In this single-pass image forming apparatus, a technique is known that uses a line head that arranges nozzles over a printable width by arranging a plurality of blocks (element groups) in which a plurality of nozzles are arranged in the width direction. However, in this case, there is a problem that it is difficult to sufficiently suppress the relative positional deviation between the blocks during assembly. On the other hand, there is a technique of assembling adjacent blocks with some overlap in the width direction, and adjusting the range of use of nozzles in each block according to the relative positions of the blocks (Patent Document 1). When printing an image using a line head divided into a plurality of blocks in this way, the processing effort can be reduced by dividing the image data corresponding to each block.

JP 2009-51066 A

However, depending on the conveying accuracy of the conveying unit that conveys the recording medium, the recording medium may not accurately advance straight in the desired direction, causing periodic positional deviation in the width direction, resulting in deterioration in image quality. Conventionally, when an attempt is made to correct the image formation position in response to this positional deviation, the data corresponding to each block becomes insufficient or overflows, making it impossible to record, and the deterioration of image quality cannot be suppressed. On the other hand, there was a problem that it takes time and effort to exchange data across blocks.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus and an image forming control method capable of performing a recording operation more easily while suppressing deterioration in image quality.

In order to achieve the above object, the invention according to claim 1,
a conveying unit that conveys the recording medium;
an acquisition unit that acquires movement information of the conveyed recording medium;
a recording operation unit having a plurality of recording elements that perform a recording operation;
a control unit;
with
the plurality of recording elements are divided into a plurality of element groups each having a plurality of recording elements;
The plurality of element groups form images in different recording ranges in a width direction perpendicular to the moving direction of the conveyed recording medium in a plane parallel to the recording medium,
the adjacent recording ranges in the width direction partially overlap in the width direction;
The driving data related to the recording operation is set so as not to perform the recording operation by the recording element corresponding to a predetermined range from the end in the width direction of the recording range,
The control unit controls, for each of the element groups, the recording device in which the set driving data associated with each of the recording elements is obtained based on the movement information for each position in the movement direction. changing a correspondence relationship between the driving data and the recording elements so as to correspond to the recording elements at positions corresponding to the amount of positional deviation in the width direction of the medium;
The image forming apparatus is characterized in that the predetermined range is determined to be equal to or greater than the maximum width of the periodic variation of the positional deviation amount.

Further, according to the invention of claim 2, in the image forming apparatus of claim 1,
The conveying unit has a mounting member for mounting the recording medium,
The amount of positional deviation is obtained based on the movement information related to the meandering movement of the mounting member.

Further, the invention according to claim 3 is the image forming apparatus according to claim 2,
The placing member is characterized by being an endless belt.

Further, according to the invention of claim 4, in the image forming apparatus of claim 2 or 3,
The placement member is provided with an index indicating a reference position,
The acquisition unit acquires the movement information of the recording medium based on the detection result of the index.

Further, the invention according to claim 5 is the image forming apparatus according to any one of claims 1 to 4,
When driving data corresponding to some of the recording elements disappears due to the change in the correspondence relationship, the control unit causes the recording elements to perform a recording operation as driving data corresponding to the part of the recording elements. It is characterized by adding data that does not exist.

Further, the invention according to claim 6 is the image forming apparatus according to any one of claims 1 to 5,
The control section is characterized by deleting the part of the driving data when there is no printing element corresponding to the part of the driving data due to the change in the correspondence relationship.

Further, the invention according to claim 7 is the image forming apparatus according to any one of claims 1 to 6,
A plurality of first storage units respectively corresponding to the element groups,
The driving data is stored in the plurality of first storage units for each range corresponding to the recording range of the element group, and processed in parallel.

Further, according to the eighth aspect of the invention, in the image forming apparatus according to the seventh aspect,
The first storage units are provided on separate substrates.

Further, the invention according to claim 9 is the image forming apparatus according to any one of claims 1 to 8,
a second storage unit that stores reference data indicating the pattern of the periodic change in the amount of positional deviation;
The control unit acquires the positional deviation amount based on the movement information using the reference data.

Further, according to the invention of claim 10, in the image forming apparatus of claim 9,
The same reference data are held in correspondence with the element groups of the recording operation unit, respectively.

Further, the invention according to claim 11 is the image forming apparatus according to any one of claims 1 to 10,
The control unit has individual control units respectively corresponding to the element groups,
The movement information is synchronously inputted to the individual control section.

Further, the invention according to claim 12 is the image forming apparatus according to any one of claims 1 to 11,
The acquisition unit is characterized by having an encoder that measures a transport movement amount by the transport unit.

Further, the invention according to claim 13 is the image forming apparatus according to any one of claims 1 to 12,
A plurality of the recording operation units are provided,
The plurality of recording operation units are arranged at different positions with respect to the movement direction of the conveyed recording medium, and at least some of them perform recording operations in a color different from that of the other recording operation units. and

Further, the invention according to claim 14,
a transport unit that transports a recording medium; an acquisition unit that acquires movement information of the transported recording medium; and a recording operation unit that has a plurality of recording elements that perform a recording operation, wherein A plurality of element groups are divided into a plurality of element groups, and the plurality of element groups form images in different recording ranges in a width direction orthogonal to a moving direction of the conveyed recording medium in a plane parallel to the recording medium. and wherein the adjacent recording ranges in the width direction partially overlap in the width direction, the image forming control method for an image forming apparatus comprising:
an initial setting step of setting the driving data related to the recording operation so that the recording element corresponding to a predetermined range from the end in the width direction of the recording range does not perform the recording operation;
For each of the element groups, the set drive data associated with each of the recording elements is obtained based on the movement information for each position in the movement direction in the width direction of the recording medium. an adjustment step of changing the correspondence relationship between the driving data and the recording elements so as to be associated with the recording elements at positions corresponding to the amount of positional deviation of
including
The predetermined range is set to be equal to or greater than the maximum width of the periodic variation of the positional deviation amount.

According to the present invention, there is an effect that the recording operation can be performed more easily while suppressing deterioration of image quality.

1 is an overall perspective view of an inkjet recording apparatus that is an embodiment of an image forming apparatus of the present invention; FIG. FIG. 4 is a bottom view showing a surface of the head unit facing the transport surface; 1 is a block diagram showing the functional configuration of an inkjet recording apparatus; FIG. FIG. 3 is a diagram showing a configuration related to processing of image data; 4 is a flow chart showing the procedure for processing a driving image; It is a figure explaining the shift of the image data with respect to meandering. It is a figure explaining the shift of the image data with respect to meandering. FIG. 10 is a diagram for explaining a supplementary operation for a nozzle having an ink ejection failure;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall perspective view of an inkjet recording apparatus 100 that is an embodiment of an image forming apparatus of the present invention.

This inkjet recording apparatus 100 has a plurality of line heads, here eight line heads, and is capable of recording a color image by ejecting ink in a single pass method. It includes a recording operation unit 20, an ink supply unit 30, a transport detection unit 41, an image detection unit 42, and the like.

The transport unit 10 includes a drive roller 11, a transport drive unit 12, a transport belt 14 (placement member), and the like. The transport drive unit 12 has a rotary motor that rotates the drive roller 11 at a predetermined speed. An endless conveying belt 14 is wound around the driving roller 11 together with a driven roller (not shown). Using the outer surface of the transport belt 14 as a transport surface, the transport unit 10 places a recording medium in a predetermined range on the transport surface, and moves the recording medium in a circular movement direction as the transport belt 14 rotates. (the moving direction of the recording medium during transportation, that is, the transportation direction). Although the type of the recording medium is not particularly limited, here, it is a continuous fabric or the like. For example, a roll-shaped fabric can be sent out sequentially, placed on the transport surface, and transported.

The recording operation unit 20 includes a carriage 22, a carriage elevating unit 23, and the like. The recording operation unit 20 is provided in the number of sets (here, 8 sets) corresponding to the number of colors of ink (a plurality of sets are provided). Each of the carriages 22 extends in a direction intersecting the transport direction of the transport unit 10 in a plane parallel to the transport surface, here, in a width direction perpendicular to the transport surface, above the transport surface of the recording medium by the transport unit 10. (height direction). The carriage 22 has nozzle openings (nozzle openings 27a; see FIG. 2) over the entire width of the conveyed recording medium (the width that can be recorded in the width direction; there may be some margins at both ends or one end). A head unit 21 (see FIG. 2; line head) is fixed so as to be able to eject ink droplets. The recording elements 26 (see FIG. 3) of each of the eight (plural) head units 21, here, nozzles, ink flow paths (ink chambers), and a configuration for ejecting ink from each of the nozzles (an electromechanical conversion element 252, which will be described later). 3) is appropriately determined according to the recording resolution, the size of the recording medium on which the ink jet recording apparatus 100 can record, and the like. A plurality of carriages 22, that is, the recording operation section 20, are provided at different positions in the transport direction. The carriage 22 is provided so that its position in the height direction can be changed by a carriage elevating unit 23, and the distance of the head unit 21 from the conveying surface is also changed as the carriage 22 moves. When the recording elements 26 each perform a recording operation (eject ink), ink is ejected from the nozzles to record (form) an image on the recording medium.

The carriage lifter 23 changes the distance of the carriage 22 from the conveying surface. The carriage lifting section 23 includes a lifting motor 232, an electromagnetic brake 233, a beam member 234, a support section 235, and the like.
Two beam members 234 are provided substantially parallel to each other in a direction intersecting the conveying direction (here, a direction orthogonal to the conveying direction, that is, a width direction) above the conveying belt 14 (on the conveying surface side of the recording medium). A support portion 235 is fixed to each end of the . The lifting motor 232 , the electromagnetic brake 233 and the carriage 22 are attached to the supporting portion 235 .
The carriage 22 is moved up and down according to the operation of an elevating motor 232 and an electromagnetic brake 233 that are driven based on a control signal from the control unit 50 (see FIG. 3) to determine its position.

The lifting motor 232 moves the carriage 22 at a predetermined lifting speed. As the lifting motor 232, for example, a servo motor or a stepping motor is used.

The electromagnetic brake 233 maintains the fixed state of the carriage 22 , and when the fixed state is released in response to a drive signal, the carriage 22 can be temporarily moved by the lift motor 232 . That is, the electromagnetic brake 233 fixes the carriage 22 in a normal state including when the power supply is cut off. A disc brake, for example, is used as the electromagnetic brake 233 .

The ink supply unit 30 stores ink of each color used for image formation and supplies the ink to the head unit 21 . Here, the ink storage tanks 31 for each color are arranged in a dedicated rack 32 and connected to the head unit 21 for ejecting each color ink through piping such as a tube. The ink of each color is not particularly limited, but eight different colors are used here, including C (cyan), M (magenta), Y (yellow) and K (black). P (pink), S (sky), G (gray), and O (orange) inks (at least part of which is a different color than the other part) can be supplied. The ink of each color is ejected as fine dots from the nozzles of the supplied head units 21 and lands on the recording medium, and is represented by a density or a combination thereof depending on the number of fine dots and the size of the dots (volume of droplets). A mixed color image is recorded. Further, the color of the ink stored in the ink storage tank 31 and supplied to the head unit 21 may be exchangeable.

The transport detection unit 41 is located on the upstream side in the transport direction with respect to the recording operation unit 20, detects the origin marker O (index indicating the reference position; see FIG. 6) of the transport belt 14, and outputs a detection signal. An origin mark O is provided at a predetermined distance from the end of the endless conveyor belt 14 in the width direction and at a specific position in the direction of revolving movement. The transport detection unit 41 detects the origin mark O each time the transport belt 14 rotates, and outputs the timing. Further, the transport detection unit 41 may be capable of measuring and outputting the position of the origin mark O in the width direction (which may be the relative position from the reference position), if necessary. The origin marker O may be, for example, a marker with a color different from that of other parts of the conveyor belt 14 or a hole provided in the conveyor belt 14 . The transport detection unit 41 may be a sensor that reads the origin mark O or acquires the detection intensity of the reflected light. It may be a transmissive optical sensor or the like that detects incident light on the opposite side. The light is not limited to visible light, and may be infrared light or the like. Further, the transport detection unit 41 may be capable of directly detecting and specifying the position (edge) of the recording medium in the width direction.

The image detection unit 42 is provided on the downstream side of the recording operation unit 20 in the conveying direction, and picks up the surface of the recording medium on which the image has been recorded by the recording operation unit 20 (or has passed without being recorded). read. The image detection unit 42 may include an illumination unit (not shown). The illumination unit illuminates the imaging surface (surface of the recording medium) of the image detection unit 42 substantially uniformly.

The image detection unit 42 includes, for example, a one-dimensional imaging sensor. Here, the one-dimensional imaging sensor has a plurality of imaging elements arranged over the width of the conveying belt 14 at least in the width direction. By moving the recording medium in the conveying direction by the operation of the conveying unit 10, the image detecting unit 42 can take two-dimensional images of the recording medium. As the imaging sensor, a CCD sensor (Charge Coupled Device), a CMOS sensor (Complementary Metal Oxide Semiconductor), or the like is used. These image pickup sensors perform an image pickup operation in which each image pickup element outputs a charge amount or a voltage corresponding to the amount of light input from the surface of a recording medium to a light receiving element via an optical system (lens). Here, the imaging sensor is capable of imaging in each wavelength band (a plurality of wavelength bands) of RGB, and the image detection unit 42 can acquire a read color image. The image detection unit 42 is used to preliminarily identify meandering information 63 and 255 (to be described later) (for example, to detect a variation pattern of a shift amount in the width direction of a straight line in the transport direction formed on the recording medium). you can
It should be noted that the transport detection unit 41 and the image detection unit 42 may have variable distances from the transport surface, similar to the carriage 22 .

FIG. 2 is a bottom view showing a surface of the head unit 21 facing the transport surface.
Here, since the head units 21 for each color have the same shape and configuration, any one of them will be described.

The head unit 21 here has eight recording heads 211a to 211h (element groups; hereinafter, some or all of them are collectively referred to as recording heads 211). The bottom surface of each recording head 211 is provided with a nozzle array in which nozzle openings 27a of a plurality of (plurality of) nozzles 27 are arranged at a predetermined nozzle pitch in the width direction. The positions of the nozzle openings 27a may be different in the transport direction as long as they are arranged at predetermined intervals in the width direction. The number and size of the nozzle openings 27a shown in this figure are for explanation purposes only. is sufficiently small compared to the width of

The eight recording heads 211 included in one head unit 21 are arranged in a zigzag pattern at different positions. Accordingly, the arrangement range of the nozzle openings 27a in the width direction of each recording head 211 is positioned differently from each other, and accordingly, images can be formed in mutually different recording ranges. The ends of the arrangement ranges of the nozzle openings 27a in the width direction of the adjacent recording heads 211 (that is, the recording range of the recording heads 211) overlap slightly. Therefore, in the head unit 21, by combining the recording ranges in the width direction of each of the eight recording heads 211, the above nozzle pitch can be obtained over the entire width of the recording medium M in the width direction (there may be some margins on both ends). Ink can be ejected from a plurality of nozzles divided into each print head 211 .

FIG. 3 is a block diagram showing the functional configuration of the inkjet recording apparatus 100. As shown in FIG.

The inkjet recording apparatus 100 includes a transport section 10, a recording operation section 20, a detection section 40 (acquisition section), a control section 50, a storage section 60, a communication section 70, a display section 81, and an operation reception section 82. , a bus 90 and the like. The transport section 10 has the transport driving section 12 described above. The detection unit 40 includes the transport detection unit 41 and the image detection unit 42 described above.

The recording operation unit 20 includes a carriage driving unit 24, a head driving unit 25, and the like. The carriage drive unit 24 outputs a drive signal to the above-described lift motor 232, electromagnetic brake 233, and the like to operate or fix them. The recording element 26 includes the electromechanical transducer 252 and the nozzle 27 as described above.

The head driving section 25 includes a recording control section 251 (individual control section). The recording control unit 251 outputs a drive signal that causes pressure fluctuations in the ink in the ink flow paths communicating with the nozzles 27 of the recording head 211 under the control of the control unit 50 . For example, an electromechanical conversion element 252 (here, a piezoelectric element) is used as a configuration for generating pressure fluctuation, and the electromechanical conversion element 252 generates deformation according to the applied voltage, that is, the output voltage of the drive signal. , the ink flow path, and in particular, the pressure chamber, which is sized and shaped to appropriately generate pressure fluctuations, is deformed. As the drive signal, one or more voltage waveform patterns are determined in advance, and the electromechanical conversion element 252 corresponding to each nozzle according to the control signal from the control unit 50 and drive data (halftone image data). Whether or not to output the drive signal in the voltage waveform pattern is determined for the voltage waveform pattern. An appropriate amount of ink pushed out from the nozzle opening 27a by the deformation operation of the electromechanical conversion element 252 (printing operation of the printing element 26) by the drive signal is separated from the ink in the ink flow path and ejected as an ink droplet. be. The output period of the drive signal may be fixed to a single period, or may be finely adjusted. Alternatively, it may be variably determined according to the transport speed of the recording medium by the transport unit 10 and the resolution in the transport direction of the image.

The recording control section 251 is provided in correspondence with each of the plurality (eight) of recording heads 211 and operates independently based on the synchronization signals from the transport detection section 41 and the encoder 43 . The recording control unit 251 controls the recording operation of each recording head 211 at the output cycle of the driving signal based on the driving data for the image range recorded by the nozzles of the corresponding recording head 211 .
The control section 50 and the recording control section 251 are included in the control section of the embodiment of the present invention.

The detection unit 40 has an encoder 43 in addition to the transportation detection unit 41 and the image detection unit 42 described above. The encoder 43 detects the rotation of the drive motor of the transport drive unit 12 or the drive roller 11, and outputs a signal corresponding to the direction of rotation for each rotation of a predetermined angle. The interval from the previous signal output indicates the rotation speed, that is, the conveying speed of the recording medium. Further, the position of the conveying belt 14 in the rotating direction and the position of the recording medium being conveyed are specified by the detection timing of the origin mark by the conveying detection unit 41 and the number of times the signal is output from the encoder 43 . A detection signal from the transport detection unit 41 and a signal for each predetermined angle from the encoder 43 are obtained as movement information of the transport belt 14 and the recording medium placed thereon.

The control unit 50 centrally controls the overall operation of the inkjet recording apparatus 100 . The control unit 50 includes a CPU 51 (Central Processing Unit), a RAM 52 (Random Access Memory), and the like. The control unit 50 performs various processes related to image formation based on image data, status signals and clock signals of each unit. In addition, the control unit 50 performs processing such as operation adjustment related to ink ejection from each nozzle 27, processing related to detection of a defective state of the ejection operation and handling thereof, and processing such as detection and adjustment of deterioration in image quality.

The CPU 51 performs various kinds of arithmetic processing, and controls the conveyance of the recording medium, the supply of ink, the ejection of ink, the reading operation of the formed image, and the like in the inkjet recording apparatus 100 . The CPU 51 performs calculations and controls related to the above processes according to programs read from the storage unit 60 .

The RAM 52 provides working memory space for the CPU 51 and stores temporary data. The storage area for the temporary data may be appropriately shared with the DRAM area of the storage unit 60 .

The storage unit 60 stores a program 61, various setting data, job data 65 relating to an image forming command, and the like. The job data 65 includes image data to be recorded, its processed data, information related to operation settings, and the like. The program 61 includes a program for specifying defective ejection nozzles that cause defective ink ejection, various image processing programs, and a distribution setting program for overlapping ranges of the nozzles 27 in the print head 211 . The setting data includes a ejection failure nozzle list 62 that indicates the positions of nozzles that have failed to eject ink (ejection failure nozzles), meandering information 63 that indicates the pattern of changes in the amount of periodic positional deviation in the width direction of the print medium. , and a distribution setting 64 that indicates a selection pattern of nozzles that are enabled to eject ink in the overlapping range of the adjacent print heads 211 . A plurality of pieces of meandering information 63 may be held according to the meandering mode that appears in the inkjet recording apparatus 100, the setting values of dependent parameters, and the like.

The storage unit 60 includes volatile memory such as DRAM and non-volatile memory here. Temporary data such as job data and processing data may be stored in volatile memory for high speed processing and erased after the image forming operation is completed. Programs, setting data, and the like are held in a nonvolatile memory and held even while power is not supplied to the inkjet printing apparatus 100 . Some programs and setting data, such as initial data and basic programs, may be stored in non-erasable and rewritable ROM instead of non-volatile memory.

The communication unit 70 is a communication interface that controls communication operations with external devices. The communication interface includes, for example, one or a plurality of network cards such as LAN cards that support various communication protocols. Under the control of the control unit 50, the communication unit 70 acquires image data to be recorded and job data including settings related to image formation from the external device, and can transmit status information and the like to the external device. can.

The display unit 81 displays the status of the inkjet recording apparatus 100 and an operation menu on the display screen according to the control signal from the control unit 50 . Examples of the display screen include a liquid crystal screen. In addition, the display unit 81 may include an LED lamp or the like for warning the presence or absence of power supply and/or an error.

The operation accepting unit 82 accepts a user's operation and outputs it to the control unit 50 . The operation reception unit 82 has, for example, a touch sensor. The touch sensor may be provided over the display screen of the display unit 81 and used as a touch panel. The control unit 50 outputs information on the position and type of the touch operation detected by the touch sensor to the control unit 50 . Also, the operation reception unit 82 may have a push button switch and/or a numeric keypad.

The bus 90 is a path that electrically connects the control unit 50 and each component that exchanges signals with the control unit 50 and transmits the signals.

Next, the flow and processing of image data will be described in more detail.

FIG. 4 is a diagram showing a configuration related to image data processing.
In the head unit 21 of the inkjet recording apparatus 100, substrates 201a to 201h (collectively referred to as substrates 201) are provided corresponding to the recording heads 211a to 211h, respectively. As described above, the recording control units 251 corresponding to the recording heads 211a to 211h are provided on the respective substrates 201 and are capable of processing operations in parallel. Further, each substrate 201 is provided with a memory 253 (first storage section). Since the configurations of the substrates 201b to 201h are the same as the configuration of the substrate 201a, description thereof is omitted here.

Based on the job data 65 stored in the storage unit 60, driving data (halftone image data) related to ink ejection from each nozzle 27 (associated with the nozzle 27) is input to each substrate 201. be. The drive data are two-dimensionally arranged according to the arrangement order in the width direction of the recording elements 26 (nozzles 27) and the drive cycle order of ink ejection (that is, the positions in the transport direction). The driving data is divided in the width direction for each recording range by each recording head 211 and sent to the memory 253 of each substrate 201 . That is, the driving operation of each recording head 211 is performed independently based on separate data (divided driving data). As described above, the divided drive data are redundantly generated for portions where the arrangement ranges (image recording ranges) of the nozzle openings 27a overlap in the width direction. Here, the entire halftone image data in the transport direction (two-dimensional array data divided in the width direction) is sent to the substrate 201, and is stored in the memory 253 while part or all of the image is formed a specified number of times. remembered.

An ejection failure nozzle list 254 and meandering information 255 (reference data) are stored in the substrates 201a to 201h, respectively. The meandering information 255 is the same as the meandering information 63 stored in the storage unit 60 . The ejection failure nozzle list 254 may be the same as the ejection failure nozzle list 62, or may be only a list of ejection failure nozzles in the recording heads 211a to 211h corresponding to the substrates 201a to 201h, respectively. Here, the ejection failure nozzle list 254 and meandering information 255 are stored in a volatile memory (second storage unit) such as a DRAM. The ejection failure nozzle list 254 and the meandering information 255 are transmitted from the storage unit 60 each time the inkjet recording apparatus 100 is activated or when an update request is made explicitly. is stored during the operation of Alternatively, the ejection failure nozzle list 254 and meandering information 255 may be continuously stored in a non-volatile memory or the like unless updated data is received.

Further, detection signals from the transport detection unit 41 and the encoder 43 are serially (chain-like) cascade-connected to each of the substrates 201a to 201h, and the detection signals are obtained (input) in synchronization with each other.

When the driving data is divided, the control unit 50 selects one of the two printheads 211 regarding the overlapping range in the width direction of the arrangement range of the nozzles 27 (printing range of the formed image) of the adjacent printheads 211 . Drive data is distributed to each. This allocation is performed for a portion mechanically allocated to one print head 211 and a portion allocated with an appropriate ejection distribution ratio based on the allocation setting 64, respectively or collectively. The drive data corresponding to the nozzles of the recording head 211 on the side to which the drive data has not been assigned are all set to non-ejection so as not to eject ink, regardless of the original drive data.

In each substrate 201, the recording control unit 251, in accordance with meandering of the recording medium (periodic positional deviation in the width direction), for each driving cycle (each of the predetermined timings) of the acquired divided driving data, By shifting (changing) the correspondence between the one-dimensional data (line data) in the width direction and the nozzles 27 (printing elements 26) arranged in order in the width direction, an image is formed at the correct position on the printing medium. Adjust so that it continues. The conveying belt 14 slightly meanders depending on the accuracy of each part such as the driving roller 11 . In other words, when the conveyor belt 14 moves in the circular movement direction, each position on the conveyor belt 14 in the circular movement direction is accompanied by a slight periodic change in position in the width direction. The recording medium can undergo periodic changes in the width direction based on the meandering of the transport belt 14 . In each of the substrates 201a to 201h, the transport belt 14 is detected by the detection timing of the origin mark by the transport detection unit 41 and the movement amount of the transport belt 14 based on the detection signal of the encoder 43 (that is, the transport movement amount and the movement speed of the recording medium). is located. By specifying the phase of this periodic change at a desired position and timing based on the movement information of the recording medium, the meandering information 255 in which this periodic change is stored is referred to (used) and the meandering is performed. is specified in the width direction. The recording control unit 251 shifts the correspondence relationship between the driving data and the nozzles 27 in the width direction by an amount corresponding to the amount of positional deviation in units of rows extending in the width direction.

After that, based on the ejection failure nozzle list 62, complementary processing is performed to distribute the ejection of the ink assigned to the ejection failure nozzle to the surrounding nozzles. The driving data after the complementary processing is sent to the recording head 211a at appropriate timing according to the clock signal, and the electromechanical conversion element 252 is deformed.

FIG. 5 is a flow chart showing the procedure for processing the drive image.
FIG. 5A is a flowchart showing the control procedure of the driving image division processing by the control unit 50. FIG. FIG. 5B is a flowchart showing a control procedure of driving image output processing by each recording control unit 251. As shown in FIG. These processes are included in the image formation control method of this embodiment.

The driving image division process is started after a halftone image is generated as image data for driving in the control unit 50 . The control unit 50 acquires a halftone image (step S101). The control unit 50 sets the recording range (arrangement range of the nozzles 27) on each substrate 201 for the halftone image (step S102). The recording range is defined redundantly on the substrate 201 corresponding to each recording head 211 with respect to the overlapping range described above.

The control unit 50 uses the allocation setting 64 to perform allocation processing for overlapping ranges. The control unit 50 divides the data range corresponding to the recording range corresponding to each substrate 201 with the overlapping range (after the allocation process) (step S103; initial setting step). The control unit 50 outputs the divided driving data (divided driving data) to each substrate 201 (step S104). Then, the control unit 50 ends the driving image division processing.

Driving image output processing by the recording control unit 251 of the substrate 201 is started when the divided driving data is input to the memory 253 . The recording control unit 251 acquires and reads the division driving data (step S201). The recording control unit 251 acquires position information and speed information (collectively, recording medium movement information) of the conveying belt 14 based on a synchronizing signal from the encoder 43 or the like, and based on this information and meandering information 255, Next, the timing (generally, nozzle 27) is obtained (step S202).

The recording control unit 251 performs correction by shifting the above line data with respect to the nozzles 27 (recording elements 26) (that is, the correspondence with the nozzles 27) by the number of nozzles corresponding to the acquired positional deviation amount. (Step S203). The processing of these steps S202 and S203 constitutes the adjustment step of this embodiment. The recording control unit 251 refers to the ejection failure nozzle list 254 and determines whether or not the set ejection failure nozzle is expected to eject ink. If ink is set to be ejected from the ejection failure nozzle, the recording control unit 251 performs ejection failure complement processing for complementing the ejection of the ejection failure nozzle with another nozzle (step S204). The recording control unit 251 outputs the driving data of the row processed as described above to each recording head 211 a predetermined time before the ejection operation (step S205).

The recording control unit 251 determines whether or not all the lines to be output (the total number of lines) have been output (step S206). This total number of lines corresponds to the total number of lines when part or all of the divided drive data is output each designated number of times (the output range may be changed for each output time). If it is determined that the total number of lines has been output ("YES" in step S206), the recording control unit 251 ends the drive image output process. If it is determined that the output of the total number of lines has not been completed ("NO" in step S206), the recording control unit 251 determines whether or not the output of the total number of lines in this output has been completed. (Step S207). If it is determined that the recording has not ended ("NO" in step S207), the processing of the recording control unit 251 returns to step S202. If it is determined that all lines have been output ("YES" in step S207), the recording control unit 251 returns the next output line to the top line of the divided drive data (step S208). Then, the processing of the recording control unit 251 returns to step S202.

Next, meandering correction and ejection failure compensation in the drive image output process will be described.

6 and 7 are diagrams for explaining the shifting of image data (driving data) with respect to meandering.

As described above, the meandering period L and the amplitude Wm in the spatial structure (the maximum amount of movement in the width direction is twice this (2 Wm)) are determined according to the above structural characteristics and arrangement (Fig. 6(a)). At the position Xi of the head unit 21, the periodic change (positional deviation) of the transport belt 14 in the width direction due to the meandering period L and the amplitude Wm is a component that moves along with the circular movement of the transport belt 14 and/or a transport component. It can be the sum of a component that vibrates at each position on the belt 14 (predetermined position in the system that moves along with the circular movement of the conveying belt 14). The parameters of the periodicity change according to these are pre-examined and stored. If the positional deviation of the recording medium with respect to the conveying belt 14 further occurs periodically, the phase of this positional deviation is measured and acquired at a predetermined point in time. Alternatively, if the distance between the position XL where the recording medium is placed on the transport belt 14 and the position X0 detected by the transport detection unit 41 is determined, it is held in advance. The amount of positional deviation (for example, a value in units of nozzle pitch) in each phase (relative position from the reference position) within the meandering period L is determined by a predetermined phase interval (or the position interval) is associated with the phase and/or position and stored as meandering information 63 and 255 .

The phase at the ink landing timing at the ink landing position from the nozzle 27 based on the drive data (row data) is determined by the above parameters, the interval between the position Xi which is the ink landing position and the position X0 detected by the transport detection unit 41, and the transport It is estimated (here, specified within a slight error range) based on at least a part of the detection results (conveyance speed, detection timing of the origin mark O, and the obtained position in the width direction) by the detection unit 41. , necessary detection contents are determined in advance (in this embodiment, the conveying speed by the encoder 43 and the detection result by the conveying detection unit 41) can be obtained. Of the drive data assigned to the memory 253 of the substrate 201 for each printhead 211, the row data corresponding to the ink landing timing for the estimated (specified) positional deviation amount is estimated as described above. The correspondence with the nozzles 27 is shifted (changed) so as to cancel out the positional deviation amount according to the phase (so that each driving data is associated with the nozzles 27 at positions according to the positional deviation amount).

When row data is shifted for each printhead 211, drive data is not exchanged between substrates 201 corresponding to adjacent printheads 211, so drive data is not transferred at one end of the shift. It protrudes, and the drive data disappears on the other hand. One and the other of these can be reversed depending on the direction of shift. In this embodiment, all of the drive data that may protrude from the recording range are set to non-ejection so as not to eject ink from the nozzles 27 .

As shown in FIG. 6B, at both ends of the overlapping range D of the nozzle arrangement range (image recording range) of the adjacent recording heads 211 (here, the recording heads 211a and 211b), (Here, it is equal to the amplitude Wm, that is, the maximum value (maximum width) of the positional deviation amount, but the total is less than the overlap range D (each is less than half the width of the overlap range D), and the width is larger than the maximum width. areas Da and Db (predetermined ranges) are determined in advance. In the area Da, which is the end portion of the print head 211a, the setting is such that ink is not ejected from the nozzles of the print head 211a (printing operations are not performed by the printing elements). All of this amount of ink is set to be discharged from the nozzles of the recording head 211b. In the area Db, which is the end portion of the print head 211b, the setting is such that ink is not ejected from the nozzles of the print head 211b (printing operations are not performed by the printing elements). All of this amount of ink is set to be ejected from the nozzles of the print head 211a. For the central portion of the overlapping range D excluding the areas Da and Db, the ink is distributed by the distribution setting 64 so that the ink is complementarily ejected from the nozzles 27 in either of the recording heads 211a and 211b as usual. be done. Here, the ejection distribution ratio, which is the ratio at which the ink can be ejected, is determined so as to gradually increase with distance from the end of the arrangement range (image recording range). A suitable method may be determined by a conventionally known appropriate method. Here, setting not to eject ink from the nozzles 27 in areas Da and Db is made separately from the distribution setting 64 , but may be included in the distribution setting 64 .

As shown in FIG. 7A, when the desired recording range a by the recording head 211a on the recording medium completely overlaps with the recording range of the recording head 211a (the same applies to the recording range b according to the recording head 211b). That is, when the amount of positional deviation of the recording medium is zero, it is determined whether or not ink can be ejected from each nozzle 27 according to the initial line data (for example, it is determined that ink can be ejected from the black portion in the figure). Whether or not ink is actually ejected from the ejectable portion is determined by the original driving data (halftone image data) In the overlapping range D, ink can be ejected from either one of the recording heads 211a and 211b. default), the image of this row is recorded at the correct position. On the other hand, as shown in FIG. 7B, when the recording medium is deviated to the right side in the figure by the width W (here, substantially equal to the amplitude Wm) due to meandering of the conveying belt 14, the recording medium The recording target range a and the recording target range b are shifted by a width W to the right with respect to the recording range by the recording heads 211a and 211b. In this state, if the ink is ejected with the original row data, the printing position of the image of this row on the printing medium will be shifted leftward by the width W. FIG. Therefore, here, the setting related to whether or not ink is ejected from each nozzle is shifted to the right by the number of nozzles corresponding to the width W. FIG.

In this case, as described above, the initial row data before the shift is defined so that ink is not ejected from the nozzles located within the area Da having a width approximately equal to the amplitude Wm from the right end of the recording head 211a. These driving data that are not ejected protrude from the portion corresponding to the nozzle 27 of the recording head 211a and disappear (part of the driving data is deleted). Since the driving data for the nozzles of the recording heads 211a and 211b in this area Da shifts from the left (the center side of the overlapping range D), complementary ejection is performed. does not occur.

Further, with respect to the nozzles (part of the driving elements) positioned within the area Db having a width approximately equal to the amplitude Wm from the left end of the recording head 211b, the corresponding driving data disappears due to the above shift. , driving data for non-ejection of ink is added. As for the driving data for the nozzles in the area Db of the printhead 211a, the data that was originally outside the overlapping range shifts from the left side, so that all the ink is ejected from the nozzles 27 of the printhead 211a into this area Db. . Therefore, even in this area Db, an abnormality such as a failure of ink ejection does not occur.

That is, with such a setting, there is no need to exchange information between the adjacent print heads 211 when shifting the position for ink ejection propriety.
Note that the above process cannot handle both ends of the recording range of the entire line head, which is not an overlapping portion. Therefore, when a halftone image is created by the control unit 50 in advance, a width margin (region where no image is formed) corresponding to the amplitude Wm may be provided at both ends of the line head (head unit 21) in the width direction. .

FIG. 8 is a diagram for explaining the complementing operation for a nozzle that has an ink ejection failure.
In this inkjet recording apparatus 100, after shifting the position (line data) of whether or not ink can be ejected according to the meandering, a complementary operation is performed when there is an ejection failure in each nozzle finally assigned to eject ink.

As shown in FIG. 8(a), if the nozzle 27f1 is an ejection failure nozzle, in this row, ink from this nozzle 27f1 is originally set to be non-ejection (impossible), so it is necessary to perform complementary processing. Absent. On the other hand, as shown in FIG. 8(b), when a shift is made according to the width W (positional deviation amount), ejection from the nozzle 27f1 is set to enabled. That is, when ink is actually set to be ejected from the nozzle 27f1 in accordance with the original driving data (halftone image data), ink is not ejected from this nozzle 27f1 but is ejected from other nozzles. Complementary processing is performed. In this case, for example, the allocation may simply be changed to nozzles at the same position in the width direction of the print head 211b.

If the nozzle 27f2 outside the overlapping range D is an ejection failure nozzle, this nozzle 27f2 will always be a nozzle capable of ejecting ink. Therefore, when there is a setting for actually ejecting ink from this nozzle 27f2, the adjacent nozzle 27c2 or the like instead of this nozzle 27f2 is set to perform ink ejection in a complementary manner. In this case, the complementary ejection from the nozzle 27c2 is not limited to the timing at which the nozzle 27f2 was originally set to eject ink, that is, within the same line data, but is not limited to the next ink ejection timing, that is, the next line data. may be carried forward to

As described above, the inkjet printing apparatus 100 of the present embodiment includes the conveying unit 10 that conveys the printing medium, the detecting unit 40 that acquires movement information of the conveyed printing medium, and the plurality of printing elements 26 ( (including the nozzle 27 and the electromechanical conversion element 252); A plurality of recording elements 26 are divided into a plurality of recording heads 211 each, and the plurality of recording heads 211 correspond to the moving direction of the conveyed recording medium (the direction of movement of the conveying belt 14 with the recording medium mounted thereon). In a plane parallel to the recording medium, images are formed in different recording ranges in the width direction perpendicular to the circular movement direction), and adjacent recording ranges in the width direction partially overlap in the width direction. The driving data related to the recording operation is set so that the recording element 26 does not perform the recording operation corresponding to a predetermined range from the end in the width direction of the recording range. , the driving data associated with each recording element 26 is the amount of positional deviation in the width direction of the recording medium obtained based on the movement information for each position in the movement direction (conveyance direction) of the recording medium. The correspondence relationship between the drive data and the recording elements 26 is changed (shifted) so that they are associated with the recording elements 26 at the corresponding positions. The predetermined range is determined to be equal to or greater than the maximum width (amplitude Wm) of the periodic change in the amount of positional deviation.
By arranging the data for which the printing operation is not performed with a width equal to or larger than the amplitude Wm in this way, when a positional deviation within the amplitude Wm occurs, the corresponding nozzle 27 (printing element 26) is shifted by the correspondence relationship shift. All of the drive data that is lost will not perform the recording operation, that is, the data that will perform the recording operation will not be lost. Therefore, according to the inkjet recording apparatus 100, the divided drive data for each recording head 211 is individually processed, and white streaks due to data loss are not generated. recording operation can be performed.

In particular, when the same image is formed a plurality of times, the generation of drive data and the correction for meandering are separated, and only the correction for meandering is most recently performed based on the detection data of the detection unit 40. It is not necessary to generate and transmit drive data with different meandering phases from the beginning each time, and the processing load can be effectively reduced.

Further, the transport unit 10 has a transport belt 14 on which a recording medium is placed, and the amount of positional deviation is obtained based on movement information related to meandering of the transport belt 14 when it moves.
By detecting the meandering state of the conveying belt 14 and using the positional misalignment of the recording medium caused by the meandering of the conveying belt 14 in this way, it becomes easy to specify the amount of positional misalignment. In particular, when the edge of the medium cannot be separated by a clear line or the like, such as cloth, it is difficult to specify the amount of misalignment of the recording medium itself. .

A mounting member on which a recording medium is mounted is an endless conveying belt 14 . By conveying the recording medium using the continuous conveying belt 14 in this way, it becomes possible to convey particularly the continuous medium stably. Misalignment is more likely to occur. Therefore, it is possible to easily continue stable image formation by correcting the positional deviation at any time as described above.

Further, the transport belt 14 is provided with an origin mark O, and the detection unit 40 (conveyance detection unit 41) acquires movement information of the recording medium based on the detection result of the origin mark O. FIG.
When the meandering period is 1/1/1 of the conveying belt length, especially when the continuous conveying belt 14 is likely to be misaligned with such a period, the position of the origin marker O is used as a reference. By specifying the position on the conveying belt 14 in the direction of revolving movement, it is possible to easily and accurately specify the phase of the periodic positional deviation. As a result, it is possible to easily specify the positional deviation amount according to the phase, quickly perform correction according to the positional deviation amount, easily suppress the deviation of the image forming position, and reduce the deterioration of the image quality. can.

Further, when driving data corresponding to a part of the recording elements 26 disappears due to a change (shift) in the correspondence relationship between the recording elements 26 (nozzles 27) and the driving data, the control unit 50 section) is added as driving data that does not cause the recording element 26 to perform the recording operation. Since the driving data for causing the recording operation to be performed by the overlapping recording head 211 is shifted to the portion where the driving data has disappeared, it is possible to simply prevent the recording operation from being performed. It is not necessary to acquire driving data corresponding to other printheads 211, and an image can be formed without defects in the printing operation by simple processing.

Further, when there are no recording elements 26 corresponding to a part of the driving data due to a change (shift) in the correspondence relationship between the recording elements 26 (nozzles 27) and the driving data, the control unit 50 controls the part of the driving data. Delete the data for That is, there is no need to send data outside the driving data of the image forming range of a certain recording head 211 to the driving data of another recording head 211 adjacent in the width direction, and the data can simply be deleted. Since the driving data outside the image forming range are the only ones that do not allow the recording operation as described above, the image will not be lost. Therefore, with the inkjet recording apparatus 100, it is possible to form an appropriate image corresponding to periodic misalignment (meandering) with a simple process while reducing deterioration in image quality.

A plurality of memories 253 corresponding to the respective printheads 211 are provided, and driving data is stored in the memories 253 for each range corresponding to the print range of the printhead 211 and processed in parallel. In this way, by separating storage and processing in terms of hardware, the inkjet printing apparatus 100 can solve problems such as an increase in the processing load of the printing control unit 251 and a limitation of the processing speed due to the limit of the data transfer speed. Therefore, it is possible to easily and quickly form an image with appropriate image quality from the image data for the long line head without causing any trouble.

Also, the memories 253 are provided on separate substrates 201a to 201h. By completely separating the hardware in this way, it can be assembled with each printhead 211 as a set. Since processing is completely independent for each substrate, it is possible to prepare data well in advance of actual image formation.

The inkjet recording apparatus 100 also includes a volatile memory such as a DRAM that stores meandering information 255 indicating a pattern of periodic changes in the amount of positional deviation of the recording medium. acquire the amount of positional deviation based on
That is, the amount of positional deviation is calculated by storing table data or the like so that the actual amount of positional deviation can be obtained according to the movement information (conveyance speed, etc.) of the recording medium and the positional information of the conveyor belt 14. It is possible to suppress an increase in the load applied to the device and quickly obtain the amount of positional deviation.

The same meandering information 255 is held corresponding to each recording head 211 of each recording operation section 20 (head unit 21). As a result, it is possible to ensure that the correction amount does not vary between the recording heads 211 . In addition, since the meandering information 255 can be easily generated and output to each substrate 201, time and effort are not required.

The control unit 50 also has a recording control unit 251 corresponding to each of the recording heads 211 , and movement information based on the detection result of the detection unit 40 is synchronously input to the recording control unit 251 . That is, since the timing of parallel processing of data corresponding to each of the plurality of printheads 211 can be aligned, misalignment associated with meandering can be easily and appropriately corrected on the same basis without complicating the timing control of processing. be able to. Therefore, the inkjet recording apparatus 100 can prevent distortion and data loss of the raster image of each line, and can stably and continuously form images without distortion and color shift.

The detector 40 also has an encoder 43 that measures the amount of movement of the conveyor belt 14 in the conveyance direction by the conveyor 10 (conveyance movement amount). By detecting the amount of rotation of the drive roller 11, etc., the position and transport speed of the recording medium can be accurately obtained in real time. Correction can be performed according to the positional deviation amount. Therefore, the inkjet recording apparatus 100 can more accurately prevent misregistration and output a high-quality image with less distortion and less color misregistration.

The inkjet recording apparatus 100 also includes a plurality of recording operation units 20 . The plurality of recording operation units 20 are arranged at different positions with respect to the movement direction of the conveyed recording medium, and at least some of them perform recording operations in colors different from those of the other recording operation units 20 to produce a color image. Output is possible.
In this way, when the head units 21 of a plurality of colors are provided at different positions in the conveying direction (rotational movement direction of the conveying belt 14) and perform recording operations with different colors, the head units 21 are arranged so as to correspond to the circumferential length of the conveying belt 14. However, if there is a positional deviation with a large period equal to or greater than the interval between the plurality of head units 21, the positional deviation (color deviation) between colors will systematically appear and become conspicuous. It is possible to suppress deterioration in image quality by suppressing color deviation. In particular, in the case of cloth, even a slight color shift is conspicuous depending on the weave pattern, etc. Therefore, deterioration in image quality can be effectively suppressed with a simple treatment.

Further, in the image formation control method of the present embodiment, the driving data related to the printing operation is set so as not to perform the printing operation by the printing element corresponding to the predetermined range from the end in the width direction of the printing range. In each of the setting steps and the recording head 211, the driving data associated with each recording element 26 is obtained based on the movement information for each position in the movement direction (conveyance direction) of the recording medium. an adjustment step of changing the correspondence relationship between the drive data and the recording elements so as to correspond to the recording elements 26 at positions corresponding to the amount of misalignment in the width direction, and the predetermined range is the amount of misalignment. is determined to be greater than or equal to the maximum width of the periodic change of
By including such an image formation control method, when a long image is formed by a line head in which a plurality of recording heads 211 are arranged, the driving data is appropriately divided according to the recording heads 211, and the image quality is improved. Efficient processing can be performed while suppressing deterioration.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible.
For example, in the above embodiment, each substrate 201 is provided for each recording head 211 and drive data is separately stored and processed. When the arrangement range of the nozzles 27 in the plurality of recording heads 211 is integrally determined (when a single recording range is determined), for example, the nozzles of the two recording heads 211 are alternately arranged in the width direction. In such a case, the drive data may be stored and processed with the head module as a unit (element group).

Further, the conveyance detection unit 41 may detect not only the origin mark O but also the position of the reference line in the conveyance direction of the conveyance belt 14 in the width direction. By acquiring this position, it is possible to measure the positional deviation amount in the width direction of the conveying belt 14 in real time. Information on the amount of positional deviation is sent to each recording control unit 251, and each recording control unit 251 specifies the amount of positional deviation of the recording medium assumed at a predetermined timing, and shifts the image data according to the amount of positional deviation. . The meandering information 255 may not be used if the amount of positional deviation of the recording medium can be directly or indirectly obtained in real time.

In the above-described embodiment, the signal from the encoder 43 is acquired to specify the correct conveying speed. If the change in the transport speed is sufficiently small, the value of the encoder 43 is not necessarily acquired, and the transport speed is fixed. You may correct|amend the amount of deviations of a phase.

Further, in the above embodiment, only a single period of meandering exists, but a plurality of periods of meandering may overlap. If the ratio of multiple cycles is an integer, the meandering information 63, 255 may be generated based on a long cycle, and if the ratio is a non-integer multiple, the meandering information may be generated separately and added. . That is, the total amount of change obtained by combining individual periodic changes does not have to be completely repeated periodically.

Moreover, in the above embodiment, the memory 253 and the recording control unit 251a are completely separated from each other in terms of hardware, but they do not necessarily have to be separated completely in terms of hardware. Data for multiple printheads 211 may be stored and processed on a single substrate. Even if they are separated by hardware, they do not have to be provided on different substrates 201 . Even in these cases, it is possible to perform the printing operation more easily without complicating the processing of the data related to the overlapping range D of the adjacent print heads 211 and suppressing the deterioration of the image quality.

In the above embodiment, the same meandering information 255 is stored on different substrates 201a to 201h. Further meandering information 255 may be stored. Further, between substrates 201 associated with different head units 21, meandering information 255 of different phases may be stored according to positions in the transport direction.

Further, in the above-described embodiment, the endless conveying belt 14 is used. , or anything else that can cause meandering. Further, the recording medium may meander due to a subtle change in the conveying direction each time the recording medium is conveyed by a plurality of rollers. In addition, as long as it is a pattern in which the amount of periodic positional deviation in the width direction can be specified (estimated) in advance in the range facing the ink landing position from the head unit 21, the cause of meandering and the occurrence range are not limited. .

In the above embodiment, the signals from the transport detection unit 41 and the encoder 43 are synchronously sent to the recording control unit 251 through the signal line that cascades between the substrates 201. It doesn't have to be cascaded if possible.

Further, in the above-described embodiment, the inkjet recording apparatus 100 has a plurality of head units 21 at different positions in the conveying direction (rotational moving direction of the conveying belt 14) and ejects inks of different colors. Alternatively, only a single color ink may be ejected from a plurality of head units 21 . In this case, for example, when the recording medium is a paper medium, even a slight misalignment or image distortion in a monochromatic image, especially a character or line drawing with clear contours, is conspicuous. It is possible to effectively suppress distortion and easily reduce deterioration in image quality.

Further, in the above-described embodiment, an ink jet recording apparatus having a large number of sets of nozzles 27 and electromechanical conversion elements 252 corresponding to the nozzles 27 as recording elements was described as an example. In the case of a line head structure in which the recording head (head module, element group) is divided and arranged so that the arrangement range (recording range) of the recording elements in each element group partially overlaps, Not limited. For example, it may be an LED printer using LED elements.
In addition, specific details such as the specific configurations, structures, processing contents, and processing procedures shown in the above embodiments can be changed as appropriate without departing from the scope of the present invention.

10 transport unit 11 drive roller 12 transport drive unit 14 transport belt 20 recording operation unit 201, 201a to 201h substrate 21 head units 211, 211a to 211h recording head 22 carriage 23 carriage elevating unit 232 elevating motor 233 electromagnetic brake 234 beam member 235 support Section 24 Carriage driving section 25 Head driving section 251, 251a Recording control section 252 Electromechanical conversion element 253 Memory 254 Discharge failure nozzle list 255 Meandering information 26 Recording element 27, 27f1, 27f2, 27c1, 27c2 Nozzle 27a Nozzle opening 30 Ink supply section 31 ink storage tank 32 rack 40 detector 41 conveyance detector 42 image detector 43 encoder 50 controller 51 CPU
52 RAMs
60 storage unit 61 program 62 ejection failure nozzle list 63 meandering information 64 distribution setting 65 job data 70 communication unit 81 display unit 82 operation reception unit 90 bus 100 inkjet recording device L meandering period M recording medium O origin mark Wm amplitude

Claims (14)

a conveying unit that conveys the recording medium;
an acquisition unit that acquires movement information of the conveyed recording medium;
a recording operation unit having a plurality of recording elements that perform a recording operation;
a control unit;
with
the plurality of recording elements are divided into a plurality of element groups each having a plurality of recording elements;
The plurality of element groups form images in different recording ranges in a width direction perpendicular to the moving direction of the conveyed recording medium in a plane parallel to the recording medium,
the adjacent recording ranges in the width direction partially overlap in the width direction;
The driving data related to the recording operation is set so as not to perform the recording operation by the recording element corresponding to a predetermined range from the end in the width direction of the recording range,
The control unit controls, for each of the element groups, the recording device in which the set driving data associated with each of the recording elements is obtained based on the movement information for each position in the movement direction. changing a correspondence relationship between the driving data and the recording elements so as to correspond to the recording elements at positions corresponding to the amount of positional deviation in the width direction of the medium;
The image forming apparatus, wherein the predetermined range is determined to be equal to or greater than the maximum width of the periodic variation of the positional deviation amount. The conveying unit has a mounting member for mounting the recording medium,
2. The image forming apparatus according to claim 1, wherein the amount of positional deviation is obtained based on the movement information related to meandering of the mounting member during movement. 3. The image forming apparatus according to claim 2, wherein the mounting member is an endless belt. The placement member is provided with an index indicating a reference position,
4. The image forming apparatus according to claim 2, wherein the acquisition unit acquires movement information of the recording medium based on a detection result of the index. When driving data corresponding to some of the recording elements disappears due to the change in the correspondence relationship, the control unit causes the recording elements to perform a recording operation as driving data corresponding to the part of the recording elements. 5. The image forming apparatus according to any one of claims 1 to 4, wherein missing data is added. 6. The control unit according to any one of claims 1 to 5, wherein when there is no printing element corresponding to a part of the driving data due to the change in the correspondence relationship, the control part deletes the part of the driving data. 1. The image forming apparatus according to claim 1. A plurality of first storage units respectively corresponding to the element groups,
7. The driving data according to claim 1, wherein the driving data are stored in the plurality of first storage units for each range corresponding to a range recorded by the element group, and processed in parallel. 1. The image forming apparatus according to claim 1. 8. The image forming apparatus according to claim 7, wherein said first storage units are provided on separate substrates. a second storage unit that stores reference data indicating the pattern of the periodic change in the amount of positional deviation;
The image forming apparatus according to any one of claims 1 to 8, wherein the control unit acquires the positional deviation amount based on the movement information using the reference data. 10. The image forming apparatus according to claim 9, wherein the same reference data is held corresponding to each of the element groups of the recording operation section. The control unit has individual control units respectively corresponding to the element groups,
The image forming apparatus according to any one of claims 1 to 10, wherein the movement information is synchronously input to the individual control units. The image forming apparatus according to any one of Claims 1 to 11, wherein the acquisition section has an encoder that measures a transport movement amount by the transport section. A plurality of the recording operation units are provided,
The plurality of recording operation units are arranged at different positions with respect to the movement direction of the conveyed recording medium, and at least some of them perform recording operations in a color different from that of the other recording operation units. The image forming apparatus according to any one of claims 1 to 12. a transport unit that transports a recording medium; an acquisition unit that acquires movement information of the transported recording medium; and a recording operation unit that has a plurality of recording elements that perform a recording operation, wherein A plurality of element groups are divided into a plurality of element groups, and the plurality of element groups form images in different recording ranges in a width direction orthogonal to a moving direction of the conveyed recording medium in a plane parallel to the recording medium. and wherein the adjacent recording ranges in the width direction partially overlap in the width direction, the image forming control method for an image forming apparatus comprising:
an initial setting step of setting the driving data related to the recording operation so that the recording element corresponding to a predetermined range from the end in the width direction of the recording range does not perform the recording operation;
For each of the element groups, the set drive data associated with each of the recording elements is obtained based on the movement information for each position in the movement direction in the width direction of the recording medium. an adjustment step of changing the correspondence relationship between the driving data and the recording elements so as to be associated with the recording elements at positions corresponding to the amount of positional deviation of
including
The image formation control method, wherein the predetermined range is determined to be equal to or greater than a maximum width of the periodic variation of the positional deviation amount.

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