JP6740807B2 - Droplet ejection data processing device, droplet ejection control device - Google Patents

Description

The present invention relates to a droplet discharge data processing device and a droplet discharge control device.

Patent Document 1 discloses a nozzle of a two-dimensional array head and a circuit for delaying data in combination. Specifically, the raster data is distributed to cache blocks, divided according to the driving timing of the two-dimensionally arranged nozzles, and the data is stored in the DRAM block corresponding to each cache block. It is described that the DRAM block shifts the address by one for each print clock.

JP, 2007-168230, A

As an example, in a two-dimensionally arranged head, each time a job is started, the initial operation is to store non-ejection data for preventing careless ejection of droplets in a storage area such as a DRAM block for delay. Therefore, the processing time increases accordingly.

It is an object of the present invention to obtain a droplet discharge data processing device and a droplet discharge control device that can omit the process of storing non-discharge data for preventing careless droplet discharge.

According to a first aspect of the present invention, a storage unit having a plurality of storage areas each capable of storing a plurality of droplet discharge data in the main scanning direction, and the droplet discharge data are stored in the storage unit. Separately from the first storage area, the pre-processing means for performing the pre-processing for providing the second storage area in which the uncertain data exists without performing the storage processing of the droplet discharge data, and the droplet discharge from the storage means. A droplet discharge data processing device having a replacement unit for replacing uncertain data existing in the second storage area with non-discharge data after reading the use data.

According to a second aspect of the present invention, in the first aspect of the present invention, the second storage area is a storage area reserved for delaying the droplet ejection, and the uncertain data is the storage area. This is empty data in which the amount of droplet ejection is uncertain.

According to a third aspect of the present invention, in the first aspect of the invention, the storage means is configured to fill a total number of storage areas of the first storage area and the second storage area. , The required number of storage elements having storage areas less than the total number of storage areas are mounted.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the droplet ejection data distinguishes at least large droplets, medium droplets, small droplets, and non-ejections. The non-ejection data is low-gradation data for instructing non-ejection.

According to a fifth aspect of the present invention, the head in which the nozzles for ejecting droplets based on the liquid droplet ejection data are two-dimensionally arranged and the droplet ejection target are relatively sub-scanned, and each main scanning line is When a droplet is ejected from the nozzle, non-ejection data corresponding to the two-dimensional array pattern is set for each of the nozzles, and the droplet ejection timing is apparently stepwise along the main scanning direction. Discharge control means for delaying and discharging, storage means having a plurality of storage areas each capable of storing a plurality of droplet discharge data in the main scanning direction, and the droplet discharge data stored in the storage means In addition to the first storage area for storing the droplet discharge data, a second storage area for storing indefinite data without performing the storage processing for the droplet discharge data is provided. After reading the droplet ejection data, the replacement unit that replaces the uncertain data existing in the second storage area with the non-ejection data, and the droplet ejection data that has been replaced by the replacement unit are sent to the ejection control unit. And a transfer unit that transfers the liquid droplets.

In the invention according to claim 6, in the invention according to claim 5, the storage means is configured to fill a total number of storage areas of the first storage area and the second storage area. , The required number of storage elements having storage areas less than the total number of storage areas are mounted.

According to a seventh aspect of the invention, in the invention according to the sixth aspect, the droplet ejection data is low gradation data that distinguishes at least large droplets, medium droplets, small droplets, and non-ejection. The non-ejection data is low gradation data that indicates non-ejection.

According to the first aspect of the present invention, it is possible to omit the process of storing non-ejection data for preventing inadvertent ejection of droplets.

According to the invention described in claim 2, it is possible to eliminate the storage processing time of the non-ejection data for the delay processing.

According to the third aspect of the present invention, it is possible to avoid waste of the information storage area by dividing the information for each delay processing.

According to the invention described in claim 4, noise (useless droplet ejection) can be prevented in the delay process.

According to the invention described in claim 5, it is possible to omit the process of storing the non-ejection data for preventing the careless ejection of the droplets.

According to the invention as set forth in claim 6, it is possible to eliminate waste of the information storage area by dividing the information for each delay processing.

According to the invention described in claim 7, noise (useless droplet ejection) can be prevented in the delay process.

FIG. 3 is a schematic configuration diagram showing an example of main components of the inkjet recording apparatus according to the present embodiment. FIG. 6 is a plan view of a print head conceptually showing a delay processing state showing a droplet discharge timing according to the present embodiment. FIG. 6 is a control block diagram of a head drive control unit provided in the main controller according to the present embodiment. 4 is a control block diagram showing details of a rearrangement processing unit of the head drive control unit shown in FIG. 3. FIG. 6 is a flowchart showing an image processing control routine in the head drive control unit according to the present embodiment. 6 is a control flowchart showing details of a rearrangement process executed in step 260 of FIG. 5. It is a conceptual diagram which shows the data storage state in the unit storage part distributed for every data (A1-A6) of A group based on this Embodiment. FIG. 8 is a transition diagram showing a state from storage of A3 data of FIG. 7 to transfer. It is a conceptual diagram which shows the data storage state in the unit storage part distributed according to each data (A1-A6) of A group based on a modification.

In the present specification, "image formation" and "printing" both mean forming and reproducing images such as characters, pictures, and photographs on paper or the like. In the present specification, “image formation” and “printing” are treated as synonymous terms in a broad sense. Further, "printing" refers to an operation at the time of forming (or printing) an image, and in the present specification, droplets (ink droplets) are ejected from nozzles of print heads 50A and 50B as an example of a head described later. That is the case) is the operation of ejecting "printing".

(Outline of device)
FIG. 1 is a schematic configuration diagram of an inkjet printer 12 as a droplet discharge device according to this embodiment.

The inkjet printer 12 includes, for example, two sets of image forming units 20A and 20B, a main controller 22, a paper feed roll 80, a discharge roll 90, and a plurality of transport rollers 100.

The image forming unit 20A includes, for example, a head driving unit 40A, a print head 50A, a heater driving unit 60A, a drying device 70A, and a paper speed detection sensor 110A.

Similarly, the image forming unit 20B includes, for example, a head driving unit 40B, a print head 50B, a heater driving unit 60B, a drying device 70B, and a paper speed detection sensor 110B.

The print head 50A includes four print heads 50AC, 50AM, 50AY, and 50AK corresponding to four colors of C color, M color, Y color, and K color, respectively, and ejects droplets of the corresponding color from the print head 50A. Discharge.

Similarly, the print head 50B includes four print heads 50BC, 50BM, 50BY, and 50BK corresponding to the four colors of C color, M color, Y color, and K color, respectively. Eject droplets.

The main controller 22 includes an image processing control system that controls the head drive unit 40A, a transport control system that controls the transport of the paper P, and a drying control system that controls the heater drive unit 60A, and the control systems work together. The image forming process is executed.

That is, the main controller 22 controls the rotation of the conveyance roller 100 connected to the paper conveyance motor via a mechanism such as a gear by driving a paper conveyance motor (not shown). A long sheet P as a recording medium is wound around the sheet feed roll 80 in the sheet transport direction, and the sheet P is transported in the sheet transport direction as the transport roller 100 rotates.

Further, the main controller 22 receives, for example, image information, and controls the image forming unit 20A based on the color information for each pixel of the image included in the received image information, so that one image forming surface of the paper P is displayed. An image corresponding to the image information is formed.

The head drive unit 40A drives the print head 50A connected to the head drive unit 40A in accordance with the droplet ejection timing instructed by the main controller 22, causes the print head 50A to eject droplets, and conveys the paper. An image corresponding to the image information is formed on one image forming surface of P.

The heater driving unit 60A includes a switching element that controls the amount of heat by turning on and off a heater (not shown) included in the drying device 70A, and drives the switching element based on an instruction from the main controller 22.

Then, the main controller 22 controls the heater driving unit 60A to dry the droplets of the image formed on the paper P by the drying air including the radiant heat from the drying device 70A toward the one image forming surface of the paper P. Then, the image is fixed on the sheet P. The main controller 22 can improve the drying efficiency by maintaining the drive current and controlling the heater on/off based on the image information. The strength of the drive current may be controlled. In addition, you may use the dry form using a laser beam as a dry form.

After that, the paper P is transported to a position facing the image forming unit 20B as the transport roller 100 rotates. At this time, the paper P is conveyed such that the other image forming surface different from the image forming surface on which the image is formed by the image forming portion 20A faces the image forming portion 20B.

The main controller 22 forms the image corresponding to the image information on the other image forming surface of the paper P by executing the same control as the above-described control for the image forming unit 20A on the image forming unit 20B.

Then, the paper P is transported to the discharge roll 90 as the transport roller 100 rotates, and is wound around the discharge roll 90.

The droplets include water-based ink, oil-based ink that is an ink that evaporates a solvent, ultraviolet curable ink, and the like, but in the present embodiment, any type of droplets can be applied.

In the following, when it is not necessary to distinguish between the image forming unit 20A and the image forming unit 20B, and the common members included in the image forming unit 20A and the image forming unit 20B, the symbols "A" and " B″ may be omitted.

As shown in FIG. 2, the print heads 50 include a plurality of heads along a direction B (for example, a direction orthogonal to each other and referred to as a main scanning direction) that intersects a conveyance direction A of the paper P (referred to as a sub scanning direction). Modules 52 are arranged. The head modules 52 have the same structure, and in FIG. 2, the first head module 52M1 to the third head module 52M3 are illustrated.

In the head module 52, nozzles that eject droplets are two-dimensionally arranged. In FIG. 2, the nozzle positions are illustrated by a matrix of row numbers (1 to 6) and column numbers (A1 to A6, B1 to B6).

The following is an example of droplet ejection execution by the print head 50.

As an example, the number of nozzles is the number in the sub scanning direction×the number in the main scanning direction=6×12, and a total of 72 nozzles are two-dimensionally arranged. The main scanning direction is classified into two groups (A group and B group) (A1 to A6 and B1 to B6).

In FIG. 2, in each head module 52, one nozzle is selected from each group (group A and group B) for each row in the sub-scanning direction (black circle (●) shown in the diagonal direction in FIG. 2). reference). The tilt angle in the oblique direction is canceled out based on the transport speed of the paper P, so that the liquid droplets that are delayed and ejected are discharged along the main scanning direction (the tilt angle is 0° with respect to the main scanning direction). It will be arranged in a line.

By the way, when printing (image formation by droplet ejection) on the paper P is started (at the time of setting for each job), the droplets are not actually ejected from the nozzles according to the delay process, and therefore the droplets are actually ejected. In addition to the actual data, it is necessary to set non-ejection data in which droplets are not ejected.

For example, the necessity of non-ejection data at each arrangement position of the group A when ejecting a droplet along the main scanning direction of the first line is shown.

When ejecting droplets from A1, it is necessary to store actual data in A1 and non-ejection data in A2 to A6.

When ejecting droplets from A2, it is necessary to store actual data in A2 and non-ejection data in A3 to A6.

When ejecting droplets from A3, it is necessary to store actual data in A3 and non-ejection data in A4 to A6.

When ejecting droplets from A4, it is necessary to store actual data in A4 and non-ejection data in A5 to A6.

That is, it can be seen that the number of stored non-ejection data is different for each arrangement number of each group.

The head drive units 40A and 40B (see FIG. 1) are controlled by the print head 50 (50A and 50B) based on the control of the head drive control unit 200 (see FIG. 3A) that functions as a part of the main controller 22. The ejection of droplets is executed.

In the head drive controller 200, an FPGA (field programmable gate array), which is a type of PLD (programmable logic device), is applied as a programming circuit that includes droplet ejection control by the print head 50. Since it may be another integrated circuit such as an ASIC (application specific integrated circuit), it will be referred to as an “integrated circuit” as a generic term below.

In the integrated circuit, a storage area 202 (see FIGS. 3A and 3B) as an example of a storage unit for storing print data (actual data and non-ejection data) is secured.

(Image processing control by the main controller 22)
FIG. 3A shows an image processing system of the main controller 22, for example, printing for acquiring image information from the outside including an information terminal and a server (not shown) and sending the head drive unit 40 (40A, 40B). FIG. 3 is a block diagram showing, by function, a head drive control unit 200 for converting into raster image data at the time. Note that the block diagram of FIG. 3A shows the control by the head drive control unit 200 classified by function, and does not limit the hardware configuration.

The image data received from the outside by the main controller 22 is input to the image conversion unit 204.

The image conversion unit 204 has a role of converting image data (print data) such as PDL into bitmap data by raster image conversion.

The image conversion unit 204 is connected to the color conversion unit 206, and the image conversion unit 204 sends the converted bitmap data to the color conversion unit 206.

The color conversion unit 206 converts the color space of the bitmap data (color space conversion processing). For example, RGB data is converted into YMCK data. In addition, the color conversion unit 206 executes a γ correction process.

The color conversion unit 206 is connected to the image processing unit 208, and the color conversion unit 206 sends the data after the color space conversion processing and the γ correction processing to the image processing unit 208.

The image processing unit 208 executes screen processing such as dither processing on the data after the color space conversion processing and the γ correction processing, and print images of low gradation (for example, 2 bits) printable by the print heads 50A and 50B. Convert to data (actual data).

The image processing unit 208 is connected to the rearrangement processing unit 210, and the image processing unit 208 sends the print image data to the rearrangement processing unit 210.

The rearrangement processing unit 210 performs rearrangement processing on the low gradation data after the screen processing based on the arrangement of the print heads 50A (50B), and sends the data to the head drive unit 40A (40B).

The rearrangement processing unit 210 has a storage area 202 for storing the data after the rearrangement processing, and stores the data (line data) for each main scan to be sent to the head drive unit 40A (40B). The head drive unit 40A (40B) drives the print head 50A (50B) based on the rearranged data, and ejects droplets in synchronization with the conveyance of the paper P.

As shown in FIG. 3B, the storage area 202 of the rearrangement processing unit 210 is an example of the required number of storage elements for each delay process, with an existing storage unit having a predetermined storage capacity as one unit. The unit storage unit 212 is prepared.

The unit storage unit 212 has a fixed storage capacity in advance in an applied integrated circuit, and in the present embodiment, a storage capacity capable of storing 3-dot data (an example of the first storage area and the second storage area). As three data areas 212A to 212C).

(Uncertain data → Non-ejection data replacement process)
FIG. 4 is a functional block diagram showing details of the processing in the rearrangement processing unit 210 of FIG. The rearrangement processing unit 210 includes a data storage unit 214 and a data transfer unit 216.

In the data storage unit 214, when the receiving unit 218 receives the print image data sent from the image processing unit 208, the receiving unit 218 temporarily stores the received data (for example, data for one sheet) in a cache memory or the like. It is temporarily stored in the unit 220.

The temporary storage unit 220 is connected to the line data acquisition unit 224. The line data fetching unit 224 fetches the printing image data for each main scan (1 line) from the temporary storage unit 220 and sends it to the storage area allocating unit 226.

The storage area allocation unit 226 executes the specification of the unit storage unit 212 provided in the storage area 202 and the allocation of the data areas 212A to 212C (address) in the specified unit storage unit 212, and the read/write unit 228. Is stored in the storage area 202 via the.

Here, the read/write unit 228 is connected to a preprocessing unit 229 as an example of a preprocessing unit.

The pre-processing unit 229 secures the storage area 202 as if data for the delay processing apparently exists at the time of setting such as job start. In other words, since the storage process in the secured storage area 202 is not actually executed, the secured storage area 202 is “empty”. However, in the present embodiment, it is assumed that the uncertain data is apparently stored. The uncertain data is data in which the gradation of the droplet is not fixed and the droplet may be ejected carelessly.

That is, indeterminate data is a kind of so-called “empty data”, but empty data includes an unused storage area in which storage processing is not executed, whereas indeterminate data is a history that storage processing has been executed. Exists.

In the storage area allocating unit 226, the storage area 202 stores apparently uncertain data in the storage area for the delay processing together with the liquid droplet ejection data (actual data) received from the line data capturing unit 224. become. The area for storing the actual data is the first storage area, and the area for apparently storing the uncertain data is the second storage area. The first storage area and the second storage area are not specified in any of the data areas 212A to 212C of any of the unit storage units 212, but are selected appropriately.

FIG. 7 is a conceptual diagram showing a storage area allocation state when the data (A1 to A6) of the group A of the head module 52 in this embodiment is stored in the storage area 202. The storage area 202 is an aggregate of the unit storage units 212.

It should be noted that at the time of setting (at the start of a job), data is not stored except for the unit storage section 212 that stores actual data for ejecting (including non-ejection) actual droplets, but as described above, Apparent uncertain data is stored.

The A1 data has the storage area 202 in the upper part (data area A) of the first unit storage section 212(1).

For the A2 data, one of the middle stage and the lower stage (data area B, 212C) of the first unit storage unit 212(1) is selected.

For the A3 data, any one of the second unit storage units 212(2) (data areas A to C) is selected.

For the A4 data, either all of the third unit storage section 212(3) (data areas A to C) or the upper part of the fourth unit storage section 212(4) (data area 212A) is selected. It

For the A5 data, the middle and lower rows of the fourth unit storage section 212 (data areas B and C) and all of the fifth unit storage section 212 (data areas A to C) are selected.

As the A6 data, all of the sixth and seventh unit storage units 212(6) and 212(7) (data areas A to C) are selected.

FIG. 8 is a transition diagram showing a state from data storage to transfer when the A3 data of FIG. 7 is taken as an example.

In the present embodiment, the data is subjected to a FIFO (First In First Out) operation.

As shown in FIG. 8A, the case is shown in which the previous job is finished and the uncertain data for the delay processing of the next job is generated. That is, the data area A is empty, uncertain data 1 is stored in the data area B, and uncertain data 2 is stored in the data area C.

Next, as shown in FIG. 8B, the uncertain data 1 in the data area B and the uncertain data 2 in the data area C stored in FIG. 8A are respectively shifted to the upper stage (data area B →A, C→B), and the actual data of the first line is stored in the data area C. Subsequently, although not shown, the uncertain data 1 in the data area A is transmitted, and the uncertain data 2 in the data area B and the actual data on the first line of the data area C are each shifted to the upper stage ( The actual data of the second line is stored in the data area B→A, C→B) and the data area C.

FIG. 8C shows the progress of continuing the FIFO operation, and after transmitting the actual data of the N-3th line of the data area C, the actual data of the N-2th line of the data area B and The actual data on the (N-1)th line of the data area C is shifted to the upper stage (data area B→A, C→B), and the actual data on the Nth line is stored in the data area C.

As shown in FIG. 4, the read/write unit 228 is connected to the line data acquisition unit 230 of the data transfer unit 216. The line data acquisition unit 230 acquires the line data read by the read/write unit 228 from the storage area 202.

The line data acquisition unit 230 is connected to the transfer unit 232 and the delay line determination unit 233.

The transfer unit 232 sends the line data acquired by the line data acquisition unit 230 to the data replacement unit 235 as an example of a replacement unit.

Further, the delay line determination unit 233 determines the presence or absence of delay processing data from the line data acquired by the line data acquisition unit 230.

The data replacement section 235 is adapted to receive a discrimination signal from the delay line discrimination section 233. The discrimination signal is a signal for discriminating whether or not the data received by the data replacement unit 235 from the transfer unit 232 includes the uncertain data which is the delay processing data.

In the data replacing section 235, based on the discrimination signal from the delay line discriminating section 233, in the case of delay processing data (uncertain data), the uncertain data is changed to non-ejection data (data indicating non-ejection as actual data). Execute the replacement process. If it is not the delay processing data (actual data), the replacement processing is not executed.

Further, when the transfer by the transfer unit 232 is completed, the line data acquisition unit 230 receives the notification of the completion of the transfer and repeats the acquisition of the next line data from the read/write unit 228.

The operation of this embodiment will be described below.

(Printing procedure)
By driving the paper transport motor, the paper P is transported from the paper feed roll 80 in the paper transport direction, image information is acquired, and the image forming unit 20A is controlled based on the color information for each pixel of the image included in the image information. By controlling, an image corresponding to the image information is formed on one image forming surface of the paper P. Then, by controlling the heater driving unit 60A, the droplets of the image formed on the sheet P are dried by the drying air including the radiant heat from the drying device 70A toward the one image forming surface of the sheet P, and the sheet is dried. Fix the image on P.

After that, the paper P is transported to a position facing the image forming unit 20B as the transport roller 100 rotates. At this time, the paper P is conveyed such that the other image forming surface different from the image forming surface on which the image is formed by the image forming unit 20A faces the image forming unit 20B, and the image forming unit 20B conveys the other surface of the paper P. An image corresponding to the image information is formed on the image forming surface of, and is dried by the drying device 70B to fix the image. Then, the paper P is transported to the discharge roll 90 as the transport roller 100 rotates, and is wound around the discharge roll 90.

FIG. 5 is a flowchart showing an image processing control routine in the head drive control unit 200 according to this embodiment.

In step 250, it is determined whether or not image data has been received, and if a negative determination is made, this routine ends.

Further, if an affirmative decision is made in step 250, the routine proceeds to step 252, where the image conversion processing is executed. In the image conversion processing, image data (print data) such as PDL is converted into bitmap data by raster image conversion.

In the next step 254, color space conversion processing of the bitmap data is executed. In the color space conversion processing, the color space of the bitmap data is converted from RGB to YMCK.

In the next step 256, the γ correction processing of the bitmap data whose color space has been converted is executed, and the routine proceeds to step 258.

In step 258, print image data is generated. In the print image data generation processing, screen processing such as dither processing is performed on the data after the color space conversion processing and the γ correction processing, and low gradation (for example, 2 bits) printable by the print heads 50A and 50B. Convert to image data for printing.

In the next step 260, a rearrangement process (detailed in FIG. 6) of the print image data is executed, and in the rearrangement process, the data is transferred to the head drive units 40A and 40B, and this routine ends. To do.

FIG. 6 is a control flowchart showing details of the rearrangement process executed in step 260 of FIG.

In step 272, the print image data (actual data for one image (one sheet of paper)) is temporarily stored in the temporary storage unit 220, and the process proceeds to step 273.

At step 273, the storage area for the delay processing is apparently secured, and the process proceeds to step 274. As a result, apparently uncertain data is stored in the storage area for the delay processing.

In step 274, one line of data is fetched from the temporary storage unit 220, then the process proceeds to step 276, and allocation to the storage area 202 is executed.

At the next step 278, based on the allocation instruction at step 276, and including the uncertain data added at step 273, it is stored in the data areas 212A to 212C in each unit storage section 212 of the storage area 202 (the book). In the embodiment, see FIG. 7).

In the present embodiment, when allocating to the storage area 202, it is apparent that the unit storage section 212 for storing the non-ejection data is not divided for each delay process, and the data areas 212A to 212A of the respective unit storage sections 212 are not divided. The number of unit storage units 212 is reduced compared to a case where the number of unit storage units 212 is partitioned for each delay process (a storage structure of a modified example shown in FIG. 9, which will be described later).

In the next step 280, it is judged whether or not it is the printing time. When an affirmative decision is made in step 280, the operation moves to step 281, one line of data is acquired from the storage area 202, and the operation moves to step 282.

In step 282, it is determined whether or not a storage area for the delay processing is secured in the acquired data. When it is determined in step 282 that the storage area for the delay processing is secured, it is determined that the uncertain data is apparently stored, and the process proceeds to step 283, where the data for the delay processing is stored. The uncertain data, which is, is replaced with the non-ejection data, and the process proceeds to step 284.

If it is determined in step 282 that the storage area for the delay process has not been secured, it is determined that the data is droplet ejection actual data, and the process proceeds to step 284.

In step 284, the acquired data (actual data and replaced non-ejection data) is transferred to the head drive unit 40A (40B).

In the next step 286, for example, the transfer is notified to the reading/writing unit 228.

In the next step 288, it is determined whether or not one image has been completed. If a negative determination is made, the process returns to step 274, and based on the transfer notification in step 286, the reading/writing unit 228 performs the next one line. Minute data is obtained and the above steps are repeated.

If the affirmative determination is made in step 288, this routine ends.

(Modification)
In this embodiment, the number of unit storage units 212 is reduced by effectively using the unit storage units 212 provided in the storage area 202 of the rearrangement processing unit 210. In the technique of apparently adding the uncertain data in (3) and replacing the non-ejection data in the transfer by the transfer unit 232, the storage area 202 does not need to have the configuration shown in FIG. It may be.

As a modified example, FIG. 9 illustrates an example in which the unit storage units 212 are distributed for each data (A1 to A6) of the A group.

At the time of setting, the following number of unit storage sections 212 are allocated to the A group of the head module 52.

A1 is a storage area for storing the actual data 1, to which one unit storage section 212 is allocated.

As A2, one unit storage unit 212 is assigned as a storage area for storing the actual data 1 and the empty data 1.

A3 is a storage area for storing the actual data 1 and the empty data 1 and 2, and one unit storage section 212 is allocated.

A4 is a storage area for storing the actual data 1 and the empty data 1 to 3, to which two unit storage units 212 are allocated.

A5 is a storage area for storing the actual data 1 and the empty data 1 to 4, to which two unit storage units 212 are allocated.

A6 is a storage area for storing the actual data 1 and the empty data 1 to 5, to which two unit storage units 212 are allocated.

In the case of this modification, a total of nine unit storage units 212 are needed because there is an unused storage area when set. For reference, in the case of the present embodiment described above (see FIG. 7), a total of seven unit storage units 212 are required.

In addition, in the present embodiment (including the modified example), the uncertain data is apparently stored for the delay process and then replaced with the non-ejection data. If some or all of the non-ejection data among the gradation data of the ejection data is not stored and is set as uncertain data and is replaced with the non-ejection data at the time of transfer, the non-ejection data is stored. The processing time can be shortened, or careless ejection of droplets on the paper P can be avoided.

In the inkjet printer 12 according to the present embodiment, two sets of image forming units 20A and 20B are arranged in series, and the paper P is reversed between the image forming units 20A and 20B, thereby Although it is possible to print on the front and back sides of P, an inkjet printer that prints on only one side may be used.

12 inkjet printer 20A, 20B image forming unit 22 main controller 40 (40A, 40B) head drive unit 50 (50A, 50B) print head 50AC, 50AM, 50AY, 50AK print head 50BC, 50BM, 50BY, 50BK print head 52 (52M1) -52M3) Head module 60A, 60B Heater drive unit 70 (70A, 70B) Dryer 80 Paper feed roll 90 Ejection roll 100 Conveying roller 110 (110A, 110B) Paper speed detection sensor 200 Head drive control unit 202 Storage area 204 Image conversion Reference numeral 206 Color conversion portion 208 Image processing portion 210 Sorting processing portion 212 Unit storage portion 212A to 212C Data area 214 Data storage portion 216 Data transfer portion 218 Reception portion 220 Temporary storage portion 224 Line data acquisition portion 226 Storage area allocation portion 228 Read/write unit 229 Pre-processing unit 230 Line data acquisition unit 232 Transfer unit 233 Delay line determination unit 235 Data replacement unit

Claims (7)

Storage means having a plurality of storage areas each capable of storing a plurality of droplet discharge data in the main scanning direction;
In addition to the first storage area for storing the droplet discharge data, the storage means is provided with a second storage area in which indeterminate data is present without storing the droplet discharge data. Pre-processing means to execute,
Replacement means for replacing the uncertain data existing in the second storage area with the non-ejection data after reading the droplet ejection data from the storage means;
A droplet discharge data processing device having a. The second storage area is a storage area secured for delaying droplet ejection, and the uncertain data is empty data in which the amount of droplet ejection is uncertain. Droplet ejection data processing device. In the storage means,
A required number of storage elements having storage areas less than the total number of storage areas are mounted so that the total number of storage areas of the first storage area and the second storage area is satisfied.
The droplet discharge data processing device according to claim 1. The droplet ejection data is low-gradation data that distinguishes at least large droplets, medium droplets, small droplets, and non-ejection, and the non-ejection data is low-gradation data that indicates non-ejection. The droplet discharge data processing device according to any one of claims 1 to 3. When ejecting droplets from the nozzles for each main scanning line while relatively sub-scanning a head in which nozzles ejecting droplets based on droplet ejection data are two-dimensionally arranged and a droplet ejection target Discharging control means that sets non-discharging data according to a two-dimensional array pattern to each of the nozzles, and apparently delays the droplet discharging timing stepwise along the main scanning direction,
Storage means having a plurality of storage areas each capable of storing a plurality of droplet discharge data in the main scanning direction;
Pre-processing for providing the storage means with a second storage area in which indeterminate data exists without storing the droplet discharge data, in addition to a first storage area for storing the droplet discharge data A preprocessing means for executing
Replacing means for replacing the uncertain data existing in the second storage area with the non-ejection data after reading the droplet ejection data from the storage means;
Transfer means for transferring the droplet discharge data after replacement by the replacement means to the discharge control means,
A droplet discharge control device having a. In the storage means,
A required number of storage elements having storage areas less than the total number of storage areas are mounted so that the total number of storage areas of the first storage area and the second storage area is satisfied.
The droplet discharge control device according to claim 5. The droplet ejection data is low-gradation data that distinguishes at least large droplets, medium droplets, small droplets, and non-ejection, and the non-ejection data is low-gradation data that indicates non-ejection. The droplet discharge control device according to claim 5 or claim 6.