JP7077541B2 - Image formation system and program - Google Patents

Description

The present invention relates to an image forming system and a program.

Some continuous-printing presses that print images on rolls of continuous strips use ink to form the images. For example, in Patent Document 1, paying attention to the fact that the time required for data processing differs for each page, data is printed on the upstream side of two continuous book printing machines arranged in series in the transport direction of roll paper. If the processing is not in time, a mechanism has been proposed in which the print of the page for which the data processing is not in time is assigned to the downstream side.

Japanese Unexamined Patent Publication No. 2016-16583

However, in the method of exclusively using the upstream machine of the two continuous book printing machines and using the downstream machine as an auxiliary method, the non-ejection period of the downstream machine may be long. In this case, if the non-discharge period of the downstream machine becomes long, the nozzle clogging cannot be avoided, and many consumables are consumed for maintenance.

Even in the method of switching the continuous book printing machine used for printing in units of print jobs composed of one page or multiple pages, the position of the nozzle actually used for ink ejection tends to be biased depending on the content of the page. The effect of reducing the consumption of ink ejected for the purpose of preventing clogging is insufficient.

In the present invention, there is an opportunity to eject droplets among the corresponding ejection positions of the plurality of forming means, as compared with the case where the print data in one page corresponding to each position of the ejection port is not allocated to the plurality of forming means. The purpose is to reduce bias.

The invention according to claim 1 is a first forming means for forming an image by ejecting droplets from a first ejection port on a continuous band-shaped recording material, and a second ejection port on the recording material. The second forming means for forming an image by ejecting droplets from the surface and the print data in one page corresponding to each ejection position are combined with the first usage history of the first ejection port and the second ejection. Based on the second usage history of the outlet, the first forming means or the allocating means to be assigned to the second forming means is provided, and the allocating means divides one page with respect to the transport direction of the recording material. When determining the allocation destination of the print data in units of a plurality of areas, it is determined that both the appearance interval in the first usage history and the second usage history are lower than a predetermined threshold value. Is obtained, it is an image forming system that determines the forming means having a larger appearance interval as the allocation destination of the print data .
The invention according to claim 2 is a first forming means for forming an image by ejecting droplets from a first ejection port on a continuous band-shaped recording material, and a second ejection port on the recording material. The second forming means for forming an image by ejecting droplets from the surface and the print data in one page corresponding to each ejection position are combined with the first usage history of the first ejection port and the second ejection. Based on the second usage history of the outlet, the first forming means or the assigning means to be assigned to the second forming means is provided, and the assigning means divides one page with respect to the transport direction of the recording material. When the allocation destination of the print data is determined in units of a plurality of areas and a determination result is obtained that the non-use period in the first usage history exceeds a predetermined threshold value, the print data is used as the print data. When it is assigned to the first forming means and a determination result is obtained that the non-use period in the first use history does not exceed the threshold value, the non-use period in the second use history is the threshold value. When the determination result that exceeds the above is obtained, the image forming system allocates the print data to the second forming means .
The invention according to claim 3 relates to a first forming means for forming an image by ejecting droplets from a first ejection port on a continuous recording material in a strip shape to a computer. Regarding the function of reading the first usage history of the above and the second forming means for forming an image by ejecting droplets from the second ejection port to the recording material, the second usage history of the second ejection port is provided. And the print data in one page corresponding to each ejection position are transferred to the first forming means or the second forming means based on the first usage history and the second usage history. It is a program for executing the allocation function, and the allocation function is the first when the allocation destination of the print data is determined in units of a plurality of areas for dividing one page in the transport direction of the recording material. When it is determined that both the usage history of the above and each appearance interval in the second usage history is lower than a predetermined threshold value, the forming means having the larger appearance interval is assigned the print data. It is a program to be decided first .
The invention according to claim 4 is the first ejection port for a first forming means for forming an image by ejecting droplets from a first ejection port on a continuous recording material in a strip shape to a computer. Regarding the function of reading the first usage history of the above and the second forming means for forming an image by ejecting droplets from the second ejection port to the recording material, the second usage history of the second ejection port is provided. And the print data in one page corresponding to each ejection position are transferred to the first forming means or the second forming means based on the first usage history and the second usage history. It is a program for executing the allocation function, and the allocation function is the first when the allocation destination of the print data is determined in units of a plurality of areas for dividing one page in the transport direction of the recording material. When a determination result is obtained that the non-use period in the usage history of the above exceeds a predetermined threshold value, the print data is assigned to the first forming means, and the non-use period in the first use history is the threshold value. When the determination result that the non-use period in the second usage history exceeds the threshold value is obtained when the determination result that the above is not exceeded is obtained, the print data is transferred to the second. It is a program assigned to the forming means.

According to the first aspect of the present invention, the allocation destination can be determined so that the difference in discharge opportunity among the plurality of forming means becomes small.
According to the invention of claim 2 , the allocation destination can be determined in consideration of the length of the non-use period.
According to the third aspect of the present invention, the allocation destination can be determined so that the difference in discharge opportunity among the plurality of forming means becomes small .
According to the invention of claim 4, the allocation destination can be determined in consideration of the length of the non-use period.

It is a figure explaining an example of the front appearance composition of the printing system which concerns on Embodiment 1. FIG. It is a figure explaining the hardware configuration example of the 1st printing apparatus and the 2nd printing apparatus constituting the printing system which concerns on Embodiment 1. FIG. It is a figure explaining the functional configuration example of the control apparatus which concerns on Embodiment 1. FIG. It is a figure explaining the print job which a print job reception part accepts. It is a figure which shows an example of the alignment mark used for the detection of the transport deviation. It is a figure explaining the analysis operation by a print data analysis part. It is a figure which shows the example of the management information which is managed based on the usage history. (A) is for managing the usage history of the upstream machine, and (B) is for managing the usage history of the downstream machine. It is a figure explaining the example of the total discharge amount for each nozzle position managed in page unit. It is a flowchart explaining the outline of the processing operation in Embodiment 1. It is a part of the flowchart explaining the determination process of the allocation destination in Embodiment 1 in detail. It is the remaining part of the flowchart explaining the determination process of the allocation destination in Embodiment 1 in detail. It is a figure explaining the relationship between the non-printable near threshold value and the non-printable threshold value. It is a flowchart explaining the outline of the processing operation in Embodiment 2. It is a figure explaining the relationship between 1 page and a partial page. It is a flowchart explaining the outline of the processing operation in Embodiment 3. It is a figure explaining the example of the image included in 1 page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position. It is a figure explaining the allocation example to the upstream machine among the images included in 1 page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position. It is a figure explaining the allocation example to the downstream machine among the images included in 1 page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position. It is a flowchart explaining the outline of the processing operation in Embodiment 4. It is a flowchart explaining the detailed content of a nozzle clogging suppression process.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

<Embodiment 1>
<Overall system configuration>
In the present embodiment, a printing system for printing an image by ejecting ink droplets on a continuous roll paper or a continuous form (hereinafter, also collectively referred to as “continuous paper”) in a strip shape will be described. The example of continuous paper is not limited to roll paper and continuous form. For example, continuous slips and form forms are also included.
FIG. 1 is a diagram illustrating an example of a front appearance configuration of the printing system 1 according to the first embodiment.
Here, the printing system 1 is an example of an image forming system, and the continuous paper P is an example of a recording material that is continuous in a strip shape.

The printing system 1 in the present embodiment rolls two printing units (that is, the first printing device 11 and the second printing device 12) that eject ink droplets onto the continuous paper P to form an image, and the continuous paper P. The continuous paper P is loaded between the pretreatment device 13 into which the supply roll 13A wound in a shape is loaded, the post-processing device 14 in which the take-up roll 14A for winding the continuous paper P into a roll is loaded, and the above-mentioned device. It has buffer devices 15, 16 and 17 that adjust the length to an integral multiple of the page length.
The ink droplet here is an example of a droplet.
Further, the first printing device 11 is an example of the first forming means, and the second printing device 12 is an example of the second forming means.

In the case of the present embodiment, the first printing device 11 and the second printing device 12 are connected in series with respect to the transport direction of the continuous paper P. In FIG. 1, the conveying direction of the continuous paper P is indicated by an arrow.
Therefore, the first printing device 11 in the present embodiment is located on the upstream side of the transport path, and the second printing device 12 is located on the downstream side of the transport path. Therefore, in the following description, the first printing device 11 may be referred to as an upstream machine, and the second printing device 12 may be referred to as a downstream machine.
The sheet-shaped continuous paper P that is continuous in a strip shape in the transport direction is continuously conveyed from the pretreatment device 13 to the post-processing device 14.

The first printing device 11 includes a control device 11A that executes various processes and controls necessary for printing, and an image output device 11B that ejects ink droplets onto the continuous paper P to be conveyed to form an image. Have.
The control device 11A has a data processing unit 11A1 that generates print data based on a print job, and a mechanism control unit 11A2 that controls the operation of the mechanism unit that constitutes the image output device 11B.

The data processing unit 11A1 executes, for example, image distortion correction, image rotation, color conversion, gradation conversion, color correction, raster conversion, and the like as processes for generating print data. Since the contents of these processes are known processes, detailed description thereof will be omitted. The print data gives the presence or absence of ink droplet ejection and the ejection amount of each nozzle.
Here, the nozzle provided in the first printing device 11 is an example of the first ejection port, and the nozzle provided in the second printing device 12 is an example of the second ejection port.
In addition, the data processing unit 11A1 also executes a process of allocating print data to the upstream machine or the downstream machine for each position of the nozzle for ejecting ink droplets as a process of generating print data. The details of this process will be described later.
The mechanism control unit 11A2 controls the operation of the mechanism unit that conveys the continuous paper P and the operation of ejecting ink droplets by the head unit.

On the other hand, the second printing device 12 includes a control device 12A that executes various processes and controls necessary for printing, and an image output device 12B that ejects ink droplets onto the continuous paper P to be conveyed to form an image. And have.
The configuration of the control device 12A and the image output device 12B is the same as the configuration of the control device 11A and the image output device 11B. Therefore, the control device 12A has a data processing unit 12A1 and a mechanism control unit 12A2.
In the example of FIG. 1, an example in which the control device 11A is built in the first printing device 11 and the control device 12A is built in the second printing device 12 is shown, but these are the first printing device 11 and the second printing. It may be housed in a control device provided in a housing separate from the device 12.

As the head unit in the present embodiment, a line head having a print width equal to or larger than the width of the area where the image is formed is used.
The line head has a configuration in which a plurality of nozzle chips having a group of nozzles (small holes) for ejecting ink droplets are arranged in the direction of the printing width. Incidentally, the direction of the print width is a direction that intersects with the transport direction of the continuous paper P, and is a so-called main scanning direction.

The head units in the present embodiment correspond to four types of yellow (Y), magenta (M), cyan (C), and black (K), and are arranged in order along the transport direction. The arrangement order from the upstream side to the downstream side is not limited to yellow (Y), magenta (M), cyan (C), and black (K).
Further, a head unit capable of ejecting ink droplets corresponding to colors other than these four colors or a head unit capable of ejecting ink droplets having the same color but different densities may be used.

Further, a head unit that ejects ink droplets used for forming a layer that is a base of the image to be formed and a layer that covers the surface of the printed image may be used. For example, a head unit that ejects other ink colors such as gold, silver, and white may be used. Further, for example, a head unit that ejects ultraviolet curable ink droplets may be used.

When forming an image on both sides of the continuous paper P, a buffer device 16 having a reversing mechanism for inverting the front and back surfaces between the time when the continuous paper P is carried in and the time when the continuous paper P is carried out is used. However, in the present embodiment, since it is assumed that an image is formed on one side, a buffer device 16 having no inversion mechanism or a buffer device 16 in which the operation of the inversion mechanism is invalidated is used.

<Configuration of each device>
FIG. 2 is a diagram illustrating a hardware configuration example of the first printing device 11 and the second printing device 12 constituting the printing system 1 according to the first embodiment.
As described above, since the first printing device 11 and the second printing device 12 have the same hardware configuration, the first printing device 11 will be exclusively described below.
As described above, the first printing device 11 has a control device 11A and an image output device 11B.

The control device 11A is configured as a so-called computer, and has an MPU (Micro Processing Unit) 21 that controls the entire device, a ROM (Read Only Memory) 22 that stores programs such as firmware, and a RAM (RAM) that is used as a program execution area. The communication interface (IF) 24 used for communication between the Random Access Memory) 23 and the image output device 11B, the communication interface (IF) 25 used for communication with the control device 12A on the downstream machine side, and the user interface. An operation panel 26 used for displaying a screen and accepting operation inputs, a panel interface (IF) 27 for passing data between the operation panel 26, and a hard disk device for storing image data and the like corresponding to a print job ( HDD) 28 and.

The image output device 11B transmits data between the communication interface 31 that communicates with the communication interface (IF) 24 in the control device 11A, the head unit 32 that corresponds to various ink droplets as described above, and the head unit 32. It has a head interface (IF) 33 for delivery, a transfer mechanism 34 for transporting continuous paper P, and a transfer interface (IF) 35 for transferring data between the transfer mechanism 34.

In the case of the present embodiment, the transport deviation detection sensor 36 is provided as a configuration peculiar to the image output device 12B constituting the second printing device 12 used as the downstream machine.
The transport misalignment detection sensor 36 is provided for the purpose of detecting the amount of misalignment of the continuous paper P in the print width direction that occurs during transport. Therefore, the transport misalignment detection sensor 36 is arranged on the upstream side of the head unit 32 where printing is started. The amount of deviation detected by the transport deviation detection sensor 36 is used to adjust the amount of deviation in the print width direction of the continuous paper P. Therefore, the second printing apparatus 12 is provided with a position adjusting mechanism (not shown).
All of the above-mentioned members including the transfer deviation detection sensor 36 are known. Therefore, detailed description of these members will be omitted.

FIG. 3 is a diagram illustrating a functional configuration example of the control device 11A according to the first embodiment. The functional configuration shown in FIG. 3 is realized through the execution of firmware.
From the viewpoint of functional configuration, the control device 11A has a print job receiving unit 41 that accepts a print job from an external device, a print data analysis unit 42 that analyzes print data for each nozzle position, and an upstream machine or an upstream machine for printing data for each nozzle position. It has an allocation destination determination unit 43 assigned to the downstream machine, and a usage history management unit 44 that manages the usage history of each nozzle for each of the upstream machine and the downstream machine.
The control device 11A from the viewpoint of the functional configuration is an example of the allocation means.

In the case of this embodiment, the print job is composed of a plurality of pages.
FIG. 4 is a diagram illustrating a print job accepted by the print job reception unit 41. The example of FIG. 4 shows a case where the print job is composed of 100 pages from # 1 to # 100.
On the continuous paper P shown in FIG. 4, an alignment mark 51 is printed at the head portion of each page in the transport direction. The alignment mark 51 is printed by the upstream machine (that is, the first printing device 11).
Here, the head portion means the end side of each page where printing is started.

FIG. 5 is a diagram showing an example of the alignment mark 51 used for detecting the transfer deviation. The alignment mark 51 has a shape in which a linear blank is provided in one diagonal direction of the square, that is, a shape in which the square is divided into two triangular patterns 51A and 51B having the same area.
The transport misalignment detection sensor 36 (see FIG. 2) described above has a light source that irradiates the continuous paper P with spot light, and a light receiving unit that receives the reflected light from the continuous paper P of the irradiated spot light. .. The light receiving unit detects a distance L1 that the spot light passes over the pattern 51A and a distance L2 that passes over the pattern 51B when the spot light crosses the alignment mark 51 in the transport direction.

When the distance L1 and the distance L2 are equal (when the spot light crosses the position _PREF ), it represents a transport state without transport deviation. On the other hand, the case where the distance L1 and the distance 2 are different (for example, when the spot light crosses the position _PR ) represents the case where there is a transport deviation. The direction of the transport deviation can be known from which of the distance L1 and the distance L2 is larger, and the magnitude of the transport deviation can be known from the difference or ratio between the distance L1 and the distance L2. The position PR in the figure indicates that the continuous paper _P is shifted to the left in the figure with respect to the direction of the print width.
The MPU 21 of the second printing device 12, which is a downstream machine, controls the transport mechanism 34 and the adjustment mechanism (not shown) based on the detected deviation amount, and the area printed by the own machine is relative to the area printed by the upstream machine. Adjust so that it does not shift.

Returning to the description of FIG.
The print data analysis unit 42 analyzes the number of appearances (discharge amount) of print data for each nozzle position for each page constituting the print job. Since the analysis target is a print job, the analysis result is a predicted value.
FIG. 6 is a diagram illustrating an analysis operation by the print data analysis unit 42. In the example shown in FIG. 6, the print pattern constituting the first page # 1 is shown by filling. Each square in the figure represents a unit area drawn by a drop of ink. In this embodiment, this area is referred to as a dot. Further, FIG. 6 is a design for the purpose of explanation.

In the example of FIG. 6, the head unit 32 is represented as being composed of 13 nozzles in the main scanning direction. Of course, this number is a tentative value for explanation.
The print data analysis unit 42 (see FIG. 3) counts the number of dots constituting the print pattern included in the corresponding dot sequence for each nozzle position. The number of dots corresponds to the discharge amount. As shown in FIG. 6, the dot row corresponds to the dot position appearing in the transport direction (sub-scanning direction), and the number of dots constituting the dot row corresponds to the length of one page (length in the transport direction). do.

In FIG. 6, the number of constituent dots of the print pattern appearing in the dot sequence corresponding to each nozzle number is represented as the total ejection amount. In the case of the example of FIG. 6, the nozzle of nozzle number 1 ejects one ink droplet during the printing period of page # 1. Hereinafter, there are three nozzles with nozzle numbers 2 and 3, two nozzles with nozzle numbers 4 to 6, one nozzle with nozzle number 7, two nozzles with nozzle numbers 8 to 10, and nozzle numbers 11 and 12. Three nozzles are ejected, and one nozzle with nozzle number 13 is ejected.

Returning to the description of FIG.
The allocation destination determination unit 43 is based on the analysis result by the print data analysis unit 42 and the usage history information of each nozzle constituting each head unit 32 of the upstream machine and the downstream machine acquired from the usage history management unit 44. The assignment destination of the print data (dot string) corresponding to each nozzle position is determined to the upstream machine or the downstream machine.
In the present embodiment, the usage history is information referred to when determining the allocation destination of print data, and is composed of various index values indicating the state of ink droplet ejection. A specific example of the usage history will be described later.
In the case of this embodiment, the allocation destination of the print data (dot string) corresponding to each nozzle position is determined with one page as the processing unit. A specific example of the determination method will be described later.

As described above, in the present embodiment, one page is set as a processing unit, and the corresponding print data allocation destination is determined for each nozzle position. Therefore, even in the case of a print job (also called variable printing) in which the content is different for each page, the print data of each page is printed according to the appearance status of the print data corresponding to each nozzle position (for example, nozzle number 7). It is possible to decide whether to print on the upstream machine side or the downstream machine side.
That is, even if there is little regularity in the appearance position of the print data for each page, the ink droplet ejection opportunity for each nozzle position can be distributed to the upstream machine and the downstream machine. As a result, it is possible to reduce the bias of the ejection opportunity at the corresponding nozzle positions between the upstream machine and the downstream machine. In other words, it is possible to avoid a situation in which the chances of ejecting ink droplets are reduced to the extent that the nozzles are clogged.
Information about the allocation destination is fed back to the usage history management unit 44.

The usage history management unit 44 manages the usage history for each nozzle of each head unit 32 provided in each of the upstream machine and the downstream machine. Here, the usage history of each nozzle of the head unit 32 provided in the first printing device 11 which is the upstream machine is an example of the first usage history, and the head unit 32 provided in the second printing device 12 which is the downstream machine. The usage history of each nozzle of No. 1 is an example of the second usage history.
In the case of the present embodiment, the usage history is given, for example, as a record of the position and time (processing timing) of the nozzle from which the ink droplet is ejected or ejected.

When there is a delay in ejecting ink droplets based on the information about the allocation destination receiving feedback from the allocation destination determination unit 43 (for example, when there is a time difference before the print data is supplied to the head unit 32 by the page buffer). , The usage history management unit 44 will manage the usage history as a predicted value.
Incidentally, when the delay can be ignored, the information regarding the allocation destination receiving feedback from the allocation destination determination unit 43 can be treated in the same manner as the actually measured value.
When the ink droplet ejection history for each head unit 32 is fed back from the image output devices 11B and 12B, the usage history management unit 44 manages the usage history of the ink droplets actually ejected from each nozzle.

FIG. 7 is a diagram showing an example of management information managed based on the usage history. (A) is for managing the usage history of the upstream machine, and (B) is for managing the usage history of the downstream machine.
The management information is information indicating the frequency of use and the usage status of each nozzle, for example, the final discharge time 61, the total discharge amount 62, the average discharge interval 63 per unit time, and the average discharge interval 64 per current print job. Is.

Here, the average ejection interval 63 per unit time is different from the average ejection interval 64 per current print job, and gives a longer-term average interval considering a plurality of print jobs.
All of these values are calculated for each nozzle number (nozzle position). The average ejection interval 63 per unit time and the average ejection interval 64 per current print job are both examples of frequency of use.

FIG. 8 is a diagram illustrating an example of a total discharge amount 62 for each nozzle position managed in page units. FIG. 8 shows an example in which the current print job is given on 100 pages, and the total ejection amount for each nozzle position is associated with the nozzle position. For example, the total discharge amount of the nozzles corresponding to the nozzle numbers 1 to 3 corresponding to the fifth page is 0, the total discharge amount of the nozzles corresponding to the nozzle number 4 is 8, and the total discharge amount of the nozzles corresponding to the nozzle numbers 5 to 10 is corresponding. The total discharge amount of the nozzles to be nozzleed is 3, and the total discharge amount of the nozzles corresponding to the nozzle numbers 11 to 13 is 0.

<Processing operation in the first embodiment>
FIG. 9 is a flowchart illustrating an outline of the processing operation according to the first embodiment.
In the case of the present embodiment, the control device 11A of the first printing device 11 as an upstream machine controls a series of processing operations through the execution of the program.
The processing operation shown in FIG. 9 is executed by the number of head units 32 provided in the upstream machine and the downstream machine. For example, it is executed for each of the head units 32 corresponding to yellow (Y), magenta (M), cyan (C) and black (K).
As described above, in the present embodiment, the print data of each nozzle position is assigned to the upstream machine or the downstream machine in units of one page.

First, the control device 11A receives the print job (step S101). In the case of the present embodiment, the length of one page of the continuous paper P in the transport direction is 60 inches, and the print job is composed of 100 pages.
The control device 11A that has received the print job updates the management information based on the usage history (step S102). Specifically, the management information calculated by using the allocation results for each of the upstream machine and the downstream machine is acquired.

Next, the control device 11A executes a process of allocating print data to the upstream machine or the downstream machine according to the nozzle position (step S103). Specifically, the control device 11A uses the management information to determine the allocation destination of the print data constituting the page being processed for each nozzle position. A detailed example of the method of determining the allocation destination will be described later.
After that, the control device 11A calculates the total ejection amount 62 for each nozzle position, the average ejection interval 63 per unit time, and the average ejection interval 64 for the current print job for each output scheduled device (steps S104 to 106). The calculation order of each value is not limited to the example of FIG. Moreover, the calculation of each value may be executed in parallel.
The calculation result here is used, for example, to update the management information in step S102.

Subsequently, the control device 11A determines whether or not the page being processed is the last page constituting the print job (step S107).
When a negative result is obtained (when the page being processed is not the last page of the print job), the control device 11A advances the processing target to the next page (step S108).
On the other hand, when an affirmative result is obtained (when the page being processed is the last page of the print job), the control device 11A ends the process of determining the allocation destination.

Subsequently, a detailed example of the allocation destination executed in step S103 will be described.
FIG. 10-1 is a part of a flowchart for explaining the allocation destination determination process in the first embodiment in detail, and FIG. 10-2 is a flowchart for explaining the allocation destination determination process in the first embodiment in detail. The rest of.
First, the control device 11A acquires management information of the nozzle position to be processed (step S111). The nozzle position to be processed starts from nozzle number 1. In the following description, the nozzle to be processed is referred to as the corresponding nozzle.

Next, the control device 11A determines whether or not there is print data at the nozzle position to be processed (step S112).
When a negative result is obtained (when the print data does not exist at the corresponding nozzle position), the control device 11A determines whether or not there is the next nozzle position (step S128).

On the other hand, when an affirmative result is obtained (when print data exists at the corresponding nozzle position), the control device 11A determines whether or not the continuous non-ejection time is within the non-printable threshold value for the corresponding nozzle of the upstream machine. (Step S113).
The continuous non-discharge time here means the time during which the non-discharge state continues, and is calculated as the difference between the current time and the final discharge time. The continuous non-discharge period is an example of the non-use period.
The non-printable threshold is the upper limit of the continuous non-ejection time at which nozzle clogging does not occur due to ink drying. The non-printable threshold is an example of a threshold corresponding to the allowable range of the non-use period.

The non-printable threshold value is not a fixed value, but changes depending on the printing environment and the number of pages in the page buffer.
The printing environment here includes, for example, the type of ink, the type of head unit 32 (for example, nozzle diameter), temperature, humidity, and printing density.
The non-printable threshold value in this embodiment is calculated by the following equation.
Non-printable threshold value = print environment threshold value + correction value Here, the print environment threshold value is the number of pages determined by the above-mentioned print environment.
The correction value is, for example, the number of pages waiting to be printed × the print length ÷ the number of pages determined by the print speed. The number of pages waiting to be printed corresponds to the number of pages in the page buffer described above. The print length corresponds to the length of one page in the transport direction, and the print speed corresponds to the transport speed.

When a negative result is obtained in step S113 (when the continuous non-discharge time of the upstream machine exceeds the non-printable threshold value), the control device 11A displays on the user interface UI that there is a possibility of print faintness for the upstream machine. (Step S114).
Following this display, the control device 11A stops printing by the upstream machine, ejects ink droplets from all the nozzles of the upstream machine, and then restarts printing by the upstream machine (step S115). This operation is performed for the purpose of preventing nozzle clogging.
After the end of step S115, the control device 11A proceeds to step S104.

On the other hand, when an affirmative result is obtained in step S113 (when the continuous non-discharge time of the upstream machine does not exceed the non-printable threshold value), the control device 11A has the continuous non-discharge time of the downstream machine within the non-printable threshold value. Whether or not it is determined (step S116).
If a negative result is obtained in step S116, the control device 11A displays on the user interface UI that there is a possibility of print fading for the downstream unit (step S117).
Following this display, the control device 11A stops printing by the downstream machine, ejects ink droplets from all the nozzles of the downstream machine, and then restarts printing by the downstream machine (step S118).
After the end of step S118, the control device 11A proceeds to step S104.

If an affirmative result is obtained in step S116, the control device 11A determines whether or not the continuous non-discharge time of the upstream machine is within the non-printable near threshold value (step S119).
FIG. 11 is a diagram illustrating the relationship between the non-printable near threshold value and the non-printable threshold value. The non-printable near threshold value is a threshold value smaller (within the allowable range) than the non-printable threshold value specified by the user, and is a preliminary threshold value used to prevent printing of the upstream machine or the downstream machine from being stopped.
If a negative result is obtained in step S119, the control device 11A sets the upstream machine as a print data output scheduled device corresponding to the corresponding nozzle (step S120).
After the end of step S120, the control device 11A proceeds to step S104.

On the other hand, if an affirmative result is obtained in step S119, the control device 11A determines whether or not the continuous non-discharge time of the downstream machine is within the non-printable near threshold value (step S121). This determination process is provided in order to avoid a complete stop of printing as shown in steps S115 and S118.
If a negative result is obtained in step S121, the control device 11A sets the downstream unit as a print data output scheduled device corresponding to the corresponding nozzle (step S122).
After the end of step S122, the control device 11A proceeds to step S104.

If an affirmative result is obtained in step S121, the control device 11A determines whether or not the appearance interval of the corresponding nozzle of the upstream machine is within the threshold value (step S123).
In the present embodiment, the average ejection interval per hour or the average ejection interval of the current print job is used as the appearance interval. This is because it is necessary to preferentially allocate print data when the ejection opportunity of the corresponding nozzle is small.
When a negative result is obtained in step S123 (when it is determined that the ejection opportunity of the corresponding nozzle of the upstream machine is small), the control device 11A sets the upstream machine as the output scheduled device (step S124).
After the end of step S124, the control device 11A proceeds to step S104.

On the other hand, if an affirmative result is obtained in step S123, the control device 11A determines whether or not the appearance interval of the corresponding nozzle of the downstream machine is within the threshold value (step S125).
When a negative result is obtained in step S125 (when it is determined that the ejection opportunity of the corresponding nozzle of the downstream machine is small), the control device 11A sets the downstream machine as the output scheduled device (step S126).
After the end of step S126, the control device 11A proceeds to step S104.

If a positive result is also obtained in step S125, the control device 11A proceeds to step S127. The process of step S127 is executed when there are many ejection opportunities for both the corresponding nozzle on the upstream machine side and the corresponding nozzle on the downstream machine side (both have the same nozzle position).
At this time, the control device 11A sets the device having the larger appearance interval as the output scheduled device (step S127). For example, when the appearance interval of the corresponding nozzle in the upstream machine is larger than the appearance interval of the corresponding nozzle in the downstream machine, the upstream machine having a smaller ejection opportunity is set as the output scheduled device. On the other hand, when the appearance interval of the corresponding nozzle in the downstream machine is larger than the appearance interval of the corresponding nozzle in the upstream machine, the downstream machine having a smaller ejection opportunity is set as the output scheduled device.

When step S127 is completed, the control device 11A proceeds to step S128 described above. The control device 11A that has advanced to step S128 determines whether or not there is a next nozzle position.
Here, if an affirmative result is obtained in step S128, the control device 11A moves the nozzle position to be processed to the next nozzle (step S129), and executes the above-mentioned processes from step S111 to step S127. ..
Eventually, when the final nozzle position is reached and a negative result is obtained in step S128, the control device 11A proceeds to step S104.

<Effect of Embodiment 1>
By using the printing system 1 in the first embodiment, the print data in one page can be assigned to the upstream machine or the downstream machine for each nozzle position based on the usage history of each nozzle position. That is, the image in one page can be printed by using the upstream machine and the downstream machine.
For example, the print data of the nozzle position having an odd number of nozzles can be printed by the upstream machine, and the print data of the nozzle position having an even number of nozzle numbers can be printed by the downstream machine.

Therefore, for example, even if the content of the image constituting the print job is different for each page, ink droplets can be preferentially ejected from the nozzle having a larger print interval or the nozzle closer to the printability threshold, and the upstream machine and the downstream machine can be used. It is possible to reduce the bias of ink ejection opportunities between the corresponding nozzle positions.
As a result, the possibility of nozzle clogging can be reduced while reducing the consumption of ink that does not contribute to the formation of the image.

In addition, since the ejection opportunities of each nozzle are increased, the occurrence of print density unevenness due to ejection defects is reduced. This leads to an improvement in image quality.
Further, by increasing the ejection opportunities of each nozzle, the possibility that the moving parts are stuck is reduced, and mechanical failure is less likely to occur.
Further, when the state in which the printing surface is limited to one surface of the continuous paper P is continued for a long period of time, one of the two printing machines constituting the printing system 1 is often used and the other is suspended. However, in such a usage mode, even if the nozzle surface of the head unit 32 is closed with a cap, the ink dries and the nozzle clogging is likely to occur.
However, by adopting the method of printing one page using the upstream machine and the downstream machine as in the first embodiment, it is possible to reduce the forced ejection of ink droplets for replacing the storage liquid and restarting the operation. Is possible, and waste of consumables can be reduced.

<Embodiment 2>
In the above-described first embodiment, the control device 11A of the upstream machine allocates the print data constituting each page to the upstream machine or the downstream machine for each nozzle position, but in the present embodiment, the inside of one page is continuous. A method is adopted in which the paper P is divided into a plurality of partial pages in the transport direction, and the print data allocation destination is determined for each partial page.

FIG. 12 is a flowchart illustrating an outline of the processing operation according to the second embodiment.
In FIG. 12, reference numerals corresponding to the portions corresponding to those in FIG. 9 are added.
Also in the case of this embodiment, the control device 11A of the first printing device 11 as an upstream machine controls a series of processing operations through the execution of the program.
In the case of the present embodiment, the control device 11A executes a process of dividing one page into partial pages after receiving the print job (step S201). In other words, in the case of the present embodiment, one page is divided into a plurality of partial pages in the transport direction of the continuous paper P. The partial page here is an example of a plurality of areas that divide one page.

By dividing one page into partial pages and assigning the print data corresponding to each partial page to the upstream machine or the downstream machine, the print data corresponding to one nozzle position can be distributed to both the upstream machine and the downstream machine within one page. It will be possible to assign.
For example, when the length of one page is 60 inches, the length of the partial page is 3 inches. In this case, one page is divided into 20 partial pages.
The more partial pages that make up one page, the easier it is for the print data corresponding to one nozzle position to be assigned to both the upstream machine and the downstream machine, but the increase in the partial pages that make up one page increases the processing load. Accompany. Further, there is a lower limit to the length of the partial pages in relation to the transport speed of the continuous paper P. In the present embodiment, this lower limit value is also referred to as a print unit length.

FIG. 13 is a diagram illustrating the relationship between one page and a partial page.
FIG. 13 shows an example in which one page is composed of five partial pages. That is, the length of the partial page is four of the print unit length.
In the case of the present embodiment, the print data corresponding to one nozzle position is assigned to the upstream machine or the downstream machine in units of partial pages, but the alignment mark 51 for alignment is at the top position of the page. If it is limited, the deviation of the printing position corresponding to one nozzle position tends to increase as the distance from the alignment mark 51 increases (toward the lower end side of one page).
Therefore, in the present embodiment, the alignment mark 51 is printed at the head position of the partial page, and even when the print data corresponding to one nozzle position is assigned to the upstream machine and the downstream machine, the printing position by the downstream machine is used. The deviation is reduced.

However, the print position of the alignment mark 51 is not limited to the partial page which is the determination unit of the allocation destination. For example, the alignment mark 51 may be arranged for each print unit length. If the number of the alignment marks 51 is large, the number of adjustment points for the positional deviation at each position along the transport direction of one page increases, so that the positional deviation can be further reduced.
The problem of misalignment is also common to the first embodiment in which the print data of each nozzle position is assigned to the upstream machine and the downstream machine in units of one page, and the third and fourth embodiments described later. Therefore, even in these embodiments, the alignment marks 51 may be formed at a plurality of positions.

Returning to the description of FIG.
When the division process into the partial pages is completed, the control device 11A sequentially executes the processes of steps S102 to 106 as in the first embodiment, and the print data allocation destination corresponding to each nozzle position is assigned to each partial page. To determine.
After that, the control device 11A determines whether or not the partial page being processed is the last partial page (step S202).
If a negative result is obtained here, the control device 11A advances the partial page to be processed to the next partial page (step S203). Proceeding to the next partial page, the control device 11A returns to step S102 and executes the series of processes described above.

On the other hand, if an affirmative result is obtained in step S202, the control device 11A determines whether or not it is the last page (step S204).
If a negative result is obtained here, the control device 11A advances the page to be processed to the next page (step S205). Proceeding to the next page, the control device 11A returns to step S201 and executes the series of processes described above.
On the other hand, if an affirmative result is obtained in step S204, the control device 11A ends the series of processes described above.

<Effect of Embodiment 2>
When the printing system 1 in the second embodiment is used, it becomes easy to allocate the print data in one page corresponding to one nozzle position to both the upstream machine and the downstream machine. For example, when the print data in one page corresponding to one nozzle position appears on different partial pages, the nozzles of the upstream machine and the nozzles of the downstream machine corresponding to one nozzle position are given an opportunity to eject ink droplets. Can be assigned.
As a result, even if the appearance position of the print data in one page is biased, the ejection opportunity can be assigned to both the upstream machine and the downstream machine.

<Embodiment 3>
In the second embodiment, one page is divided into a plurality of partial pages in the transport direction of the continuous paper P, and the print data allocation destination is determined for each partial page. However, in the present embodiment, one page is determined. A method of determining the print data allocation destination for each image contained in the image is adopted.

FIG. 14 is a flowchart illustrating an outline of the processing operation according to the third embodiment.
FIG. 14 is shown with reference numerals corresponding to the portions corresponding to those in FIG.
Also in the case of this embodiment, the control device 11A of the first printing device 11 as an upstream machine controls a series of processing operations through the execution of the program.
In the case of the present embodiment, the control device 11A executes a process of dividing one page into image units after receiving the print job (step S301). In the case of the present embodiment, the image means a continuous area as an independent area in the partial area including the print data. Each image is an example of a continuous partial area in one page, and is also an example of a plurality of areas that divide one page.

FIG. 15 is a diagram illustrating an example of an image included in one page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position.
In the example of FIG. 15, in order to allocate the print data corresponding to each nozzle position to the upstream machine and the downstream machine on a page-by-page basis, only one alignment mark 51 is arranged at the head portion.
In the case of the example of FIG. 15, four images are included. The four are a line segment image 71 extending in the transport direction, a line segment image 72 extending in a direction intersecting the transport direction, an elliptical image 73, and a rectangular image 74. The line segment images 71 and 72, the ellipse image 73, and the rectangular image 74 all belong to the graphic image. The graphic image also includes the alignment mark 51 described above.

Of course, the number and types of images are examples. For example, the image may include characters, patterns, etc., and may be distinguished by layer.
Further, each image may be a raster image (so-called bitmap image) which is a set of dots, or may be a vector image represented by a plurality of coordinate points and a line connecting them.
The control device 11A extracts an image included in the page to be processed through image processing and analysis processing.

In the case of the example of FIG. 15, there is an opportunity to eject ink droplets at many nozzle positions except for some nozzle positions.
By dividing one page into image units and assigning the print data corresponding to each image to the upstream machine or the downstream machine, the print data corresponding to one nozzle position is divided into a plurality of pieces in one page, and the upstream machine or the downstream machine is used. It will be possible to assign it to the machine.

FIG. 16 is a diagram illustrating an example of allocation to an upstream machine among the images included in one page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position.
In the example of FIG. 16, the alignment mark 51 and the line segment image 72 extending in the direction intersecting the transport direction are assigned to the upstream machine, and ink droplet ejection opportunities are assigned to many nozzle positions on the upstream machine side. Has been done.

FIG. 17 is a diagram illustrating an example of allocation to a downstream machine among the images included in one page. (A) shows a printing example of one page, and (B) shows the distribution of the ejection amount for each nozzle position.
In the example of FIG. 17, a line segment image 71 extending in the transport direction, an elliptical image 73, and a rectangular image 74 are assigned to the downstream machine, and ink droplet ejection opportunities are assigned to many nozzle positions on the downstream machine side. Has been done.
It should be noted that the image allocation shown in FIGS. 16 and 17 is not simply determined so as to reduce the bias in the number of nozzles that eject ink droplets in the page, but the use of each nozzle is used as described later. Determined based on historical information.

Returning to the description of FIG.
When the division process into a plurality of images included in the page to be processed is completed, the control device 11A sequentially executes the processes of steps S102 to 106 for one image selected as the process target, and sets the individual nozzle positions. Determine the allocation destination of the corresponding print data.
After that, the control device 11A determines whether or not the image to be processed is the last image in the page (step S302).
If a negative result is obtained here, the control device 11A advances to the next image as a processing target (step S303). When the next image is selected, the control device 11A returns to step S102 and executes the series of processes described above.

On the other hand, if an affirmative result is obtained in step S302, the control device 11A determines whether or not it is the last page (step S304).
If a negative result is obtained here, the control device 11A advances the page to be processed to the next page (step S305). Proceeding to the next page, the control device 11A returns to step S301 and executes the series of processes described above.
On the other hand, if an affirmative result is obtained in step S304, the control device 11A ends the series of processes described above.

<Effect of Embodiment 3>
By using the printing system 1 in the third embodiment, the print data in one page corresponding to one nozzle position can be assigned to the upstream machine or the downstream machine in image units. Therefore, when the print data in one page corresponding to one nozzle position appears in different images, there is an opportunity to eject ink droplets to each of the nozzles of the upstream machine and the nozzles of the downstream machine corresponding to one nozzle position. Can be assigned.
As a result, even if there is a bias in the appearance position of the print data in one page, the ejection opportunity can be assigned to both the upstream machine and the downstream machine.

<Embodiment 4>
In the present embodiment, in addition to the processing operation shown in the third embodiment, a processing function for suppressing clogging of a specific nozzle having a small chance of ejecting ink droplets is added.
FIG. 18 is a flowchart illustrating an outline of the processing operation according to the fourth embodiment.
FIG. 18 is shown with reference numerals corresponding to the portions corresponding to those in FIG.
Also in the case of this embodiment, the control device 11A of the first printing device 11 as an upstream machine controls a series of processing operations through the execution of the program.

The process specific to the process procedure shown in FIG. 18 is step S401, which is executed after the process of allocating the print data to the last image in the page is completed (after a positive result is obtained in step S302).
In step S401, the nozzle clogging suppressing process is executed for a specific nozzle having a small chance of ejecting ink droplets in the page to be processed.

FIG. 19 is a flowchart illustrating the detailed contents of the nozzle clogging suppressing process.
The processes shown in FIG. 19 are sequentially executed for the individual nozzle positions constituting the head unit 32.
First, the control device 11A determines whether or not the continuous non-discharge time of the upstream machine corresponding to the nozzle position to be processed is within the non-printable near threshold value (step S411).
The non-printable near threshold value here corresponds to the threshold value (see FIG. 11) described in the first embodiment.

If a negative result is obtained in step S411, the control device 11A selects a blank area in which print data does not exist and adds print data to the corresponding nozzle of the upstream machine (step S412). Step S412 is executed for the purpose of forcibly ejecting ink droplets to the corresponding nozzle whose continuous non-ejection time is longer than the threshold value set by the user. The blank area is selected so that the ejection position of the ink droplets forcibly ejected is not conspicuous. Since the amount of ink droplets ejected is small, it does not visually affect the quality of the image.
Further, the blank area is selected in order to prevent color mixing with the ink droplets ejected by the downstream machine.

On the other hand, if an affirmative result is obtained in step S411, the control device 11A determines whether or not the continuous non-discharge time of the downstream machine corresponding to the nozzle position to be processed is within the non-printable near threshold value (step S413). ).
If a negative result is obtained in step S413, the control device 11A selects a blank area in which print data does not exist and adds print data to the corresponding nozzle of the downstream machine (step S414).

After the execution of step S412, or when a positive result is obtained in step S413, or after the execution of step S414, the control device 11A calculates the total discharge amount for each nozzle position for each output scheduled device (step S415). ).
Subsequently, the control device 11A also calculates the average ejection interval 63 per unit time and the average ejection interval 64 per current print job (steps S416 and 417).
These processes are executed in order to reflect the print data added due to the forced ejection of ink droplets in each information.

After that, the control device 11A determines whether or not it is the last nozzle position (step S418), and while a negative result is obtained, proceeds to step S419 to change the processing target to the next nozzle.
If an affirmative result is obtained in step S418, the control device 11A ends the nozzle clogging suppressing process and proceeds to step S304.

<Effect of Embodiment 4>
If the printing system 1 in the fourth embodiment is used, ink droplets are forcibly ejected at nozzle positions where print data does not appear for a long period of time, and the printing operation of the entire upstream machine or the entire downstream machine is forced. It is possible to avoid the situation where the system is stopped.
The processing function for suppressing clogging of a specific nozzle having a small ejection opportunity in the present embodiment can also be combined with the above-described first and second embodiments.

<Other embodiments>
Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear from the description of the claims that the above-described embodiment with various modifications or improvements is also included in the technical scope of the present invention.

For example, in the above-mentioned embodiments 3 and 4, print data is assigned to the upstream machine or the downstream machine in image units, but it may be combined with the second embodiment. That is, one page may be divided into partial pages, and the print data corresponding to each nozzle position may be assigned to the upstream machine or the downstream machine for each image in the partial page. In this case, since one image is likely to appear across a plurality of partial pages, it is easy to allocate the print data in one page corresponding to one nozzle position to both the upstream machine and the downstream machine. As a result, regarding the nozzle position in the range where the image appears, both the nozzle on the upstream machine side and the nozzle on the downstream machine side can secure a ejection opportunity, and the continuous non-ejection time or the average ejection interval can be shortened.

Further, in the above-described embodiment, the process of executing the allocation destination of the print data constituting one page for each nozzle position is applied regardless of the difference in the print job, but the printer type can be stopped in units of one page. If the number of pages of the print job does not reach the downstream machine, it is not necessary to execute the above-mentioned process of determining the print data allocation destination for the print job.
Further, although not described in the above-described embodiment, if the time required for the page printed by the upstream machine to be conveyed to the downstream machine is less than the drying time, the print data is sent to the downstream machine. You may not assign it.

Further, in the above-described embodiment, the determination of the print data allocation destination is executed by the control device 11A on the upstream machine side, but the determination may be executed by the control device 12A on the downstream machine side.
Further, the decision is made on the higher-level device side that manages the print job connected to the information processing device or the printing system 1 in a housing separate from the first printing device 11 as the upstream machine and the second printing device 12 as the downstream machine. You may execute it with.

1 ... printing system, 11 ... first printing device (upstream machine), 11A, 12A ... control device, 11A1, 12A1 ... data processing unit, 11A2, 12A2 ... mechanism control unit, 11B, 12B ... image output device, 12 ... 2 Printing device (downstream machine), 41 ... Print job reception unit, 42 ... Print data analysis unit, 43 ... Allocation destination determination unit, 44 ... Usage history management unit, 51 ... Alignment mark

Claims (4)

A first forming means for forming an image by ejecting droplets from a first ejection port on a continuous recording material in a strip shape,
A second forming means for forming an image by ejecting droplets from the second ejection port onto the recording material,
The print data in one page corresponding to each ejection position is printed on the first forming means or the first forming means based on the first usage history of the first ejection port and the second usage history of the second ejection port. With the allocation means assigned to the second forming means
Have,
When the allocation means determines the allocation destination of the print data in units of a plurality of areas for dividing one page in the transport direction of the recording material.
When it is determined that both the appearance interval in the first usage history and the second usage history are lower than the predetermined threshold value, the determination result is obtained.
The forming means having a larger appearance interval is determined as the allocation destination of the print data .
Image formation system. A first forming means for forming an image by ejecting droplets from a first ejection port on a continuous recording material in a strip shape,
A second forming means for forming an image by ejecting droplets from the second ejection port onto the recording material,
The print data in one page corresponding to each ejection position is printed on the first forming means or the first forming means based on the first usage history of the first ejection port and the second usage history of the second ejection port. With the allocation means assigned to the second forming means
Have,
When the allocation means determines the allocation destination of the print data in units of a plurality of areas for dividing one page in the transport direction of the recording material.
When it is determined that the non-use period in the first use history exceeds a predetermined threshold value, the print data is assigned to the first forming means.
When a determination result is obtained that the non-use period in the first usage history does not exceed the threshold value, a determination result is obtained that the non-use period in the second usage history exceeds the threshold value. When it is, the print data is assigned to the second forming means .
Image formation system. On the computer
With respect to the first forming means for forming an image by ejecting droplets from the first ejection port to a continuous recording material in a strip shape, a function of reading the first usage history of the first ejection port and the function of reading out the first usage history of the first ejection port.
With respect to the second forming means for forming an image by ejecting droplets from the second ejection port to the recording material, a function of reading out a second usage history of the second ejection port and the like.
The function of allocating the print data in one page corresponding to each ejection position to the first forming means or the second forming means based on the first usage history and the second usage history is executed. It is a program to make
The allotting function is used when determining the allocation destination of the print data in units of a plurality of areas for dividing one page in the transport direction of the recording material.
When it is determined that both the appearance interval in the first usage history and the second usage history are lower than the predetermined threshold value, the determination result is obtained.
The forming means having a larger appearance interval is determined as the allocation destination of the print data.
program. On the computer
With respect to the first forming means for forming an image by ejecting droplets from the first ejection port to a continuous recording material in a strip shape, a function of reading the first usage history of the first ejection port and the function of reading out the first usage history of the first ejection port.
With respect to the second forming means for forming an image by ejecting droplets from the second ejection port to the recording material, a function of reading out a second usage history of the second ejection port and the like.
A function of assigning print data in one page corresponding to each ejection position to the first forming means or the second forming means based on the first usage history and the second usage history.
It is a program to execute
The allotting function is used when determining the allocation destination of the print data in units of a plurality of areas for dividing one page in the transport direction of the recording material.
When it is determined that the non-use period in the first use history exceeds a predetermined threshold value, the print data is assigned to the first forming means.
When a determination result is obtained that the non-use period in the first usage history does not exceed the threshold value, a determination result is obtained that the non-use period in the second usage history exceeds the threshold value. When it is, the print data is assigned to the second forming means.
program.

Images