JP2013111812A - Printing system and printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform maintenance processing such as preliminary ejection, detection of undischarged nozzles and recovery of nozzles during printing on continuous paper.
A printing system that controls a printing apparatus that performs printing using a plurality of ejection nozzles arranged at least as wide as a printing medium that is continuously conveyed, the ejection of the ejection nozzles during conveyance of the printing medium. An adjustment unit that performs a state adjustment process; and a control unit that performs control to reduce a conveyance speed at which the print medium is conveyed when the adjustment process is performed by the adjustment unit.
[Selection] Figure 2

Description

  The present invention relates to a technique for performing a maintenance process during printing on continuous paper.

  Image recording with an ink jet printer is performed by ejecting small ink droplets onto a recording medium from a head having a plurality of ejection openings (nozzles). As an inkjet printer capable of high-speed printing, a print medium passes once through the head array using a head having a nozzle array with a width of the print medium in a direction perpendicular to the moving direction of the print medium. A so-called one-pass method for completing printing is known.

  An ink jet printer forms an image by switching the ink OFF / ON signal using each nozzle. When ink is not ejected despite the ON signal (hereinafter referred to as non-ejection), a streak pattern is formed on the formed image. I will enter. In addition, even if a streak pattern due to non-ejection does not occur, a necessary ejection amount cannot be obtained, and a phenomenon that the edge of the image becomes thin occurs.

  In order to maintain a stable print quality, it is desirable to frequently perform preliminary discharge for stabilizing discharge in order to eliminate the uneven temperature of the head that occurs between nozzles used for printing and nozzles that are not used. In addition, it is desirable to detect undischarge nozzles that are no longer discharged, for example, once every several hundred sheets, and to remove bubbles that cause undischarge.

  Accordingly, the following maintenance process is performed in a serial type ink jet printer that forms an image by reciprocating a plurality of times on a recording medium with a relatively short head. Since the moving range of the head is larger than the recording medium, ink is ejected before and after the head passes through the recording medium to perform preliminary ejection and detection and recovery of the non-ejection nozzle.

  Patent Document 1 describes a head maintenance method in the case of so-called cut sheet printing which is cut to an arbitrary size perpendicular to the moving direction of the recording medium. Specifically, preliminary ejection may be performed by ejecting ink droplets from the ejection port between the recording medium when the recording medium is moved, that is, when there is no recording medium immediately below the head. It describes the detection of vomiting.

  Patent Document 2 describes a maintenance method for a one-pass ink jet printer capable of high-speed printing using continuous paper (roll paper) instead of cut paper. Japanese Patent Application Laid-Open No. 2004-228688 describes a technique in which a sensor is arranged in a direction parallel to the head, the discharge state of the discharge port used in the image forming process is monitored, non-discharge is detected and corrected in real time.

  Patent Document 3 describes that a one-pass inkjet printer is provided with a mechanism for moving the head away from the continuous paper and retracting to restore the ejection function.

JP 2011-116139 A JP 2010-75813 A Japanese Patent No. 3828411

However, when printing using continuous paper by the one-pass method, since the head does not scan like the serial method, the print quality cannot be stabilized using the same method as the serial method. In addition, as in Japanese Patent Application Laid-Open No. H10-26083, when a mechanism is used to retreat the head from the recording medium according to the serial method, an operation during a printing operation is difficult, and the number of continuously printable sheets is limited. In particular, when continuous paper is used to perform 3000PPM (Pages / Minute) class high-speed printing, the paper conveyance speed of continuous paper reaches approximately several hundreds of meters per minute. A lot of paper is wasted and is not realistic.
On the other hand, in the method described in Patent Document 2, undischargeable nozzles can be detected, but only nozzles used for image formation are detected, and all nozzles cannot be detected. Pre-discharge is not possible.
The present invention has been made in view of the above problems, and an object thereof is to enable maintenance processing such as preliminary ejection, detection of undischarged nozzles, and recovery of nozzles during printing on continuous paper.

  In order to solve the above-described problem, a printing system according to the present invention is a printing system that controls a printing apparatus that performs printing using a plurality of ejection nozzles arranged at least for the width of a continuously conveyed printing medium, An adjustment unit that performs adjustment processing of the discharge state of the discharge nozzles during conveyance of the print medium, and a control unit that performs control to reduce the conveyance speed at which the print medium is conveyed when adjustment processing by the adjustment unit is performed. And having.

  According to the present invention, it is possible to perform maintenance processing such as preliminary ejection, detection of undischarged nozzles, and nozzle recovery during printing on continuous paper.

1 is a diagram illustrating a configuration of a printing apparatus according to an embodiment. It is a figure which shows the structure of the printing control apparatus which concerns on this embodiment. It is a figure which shows the flow of the process of the printing control which concerns on this embodiment. It is a figure which shows the relationship between the nozzle which concerns on this embodiment, and temperature. It is a figure which shows the flow of the maintenance process which concerns on this embodiment. It is a figure which shows the example of a nozzle undischarge detection. It is a figure which shows the example of the motor control which concerns on this embodiment. It is a figure which shows the relationship between the nozzle which concerns on this embodiment, and temperature. It is a figure which shows the example of the paper conveyance speed which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, about the same structure, the same code | symbol is attached | subjected and demonstrated.

  The printing system according to the present exemplary embodiment includes a printing apparatus 203 and a printing control apparatus 202 that controls the printing apparatus 203.

(Printer configuration)
In the present embodiment, an ink jet printer will be described as an example of the printing apparatus 203 that performs printing using a plurality of ejection nozzles arranged at least in the width of a continuously conveyed printing medium. The ink jet printer is a one-pass method in which an image is formed by a single scan (one scan) while conveying continuous paper (roll paper) at a high speed under the ink jet print head. Further, four inks of C, M, Y, and K, which are basic four color materials of the printer, are connected to the head. The number of color materials is not limited to the above, and light inks having the same hue and different densities, or so-called special color inks such as R, G, and B used for improving the color reproduction range may be connected. Further, the head may be a head having a length corresponding to the width of the print medium by using a plurality of ejection nozzles as blocks.

  FIG. 1 shows the configuration of the printer of this embodiment. In FIG. 1, a recording medium supply unit 101 supplies a recording medium that is continuous paper for printing. The recording medium 102 is continuous paper as a recording medium. The recording medium winding unit 103 winds up the printed recording medium. The recording medium conveying units 104 to 107 convey the recording medium before and after printing. The printing unit 108 has a head including a nozzle row having a length corresponding to the width of the printing medium. In this embodiment, the number of inks (heads) to be printed is not limited. In that case, a plurality of heads may be installed in the printing unit 108 as a head row, or the recording medium transport units 104 to 107 and the printing unit 108 are set in each color, and the recording medium supply unit 101 and the recording medium winding unit 103 are set. A plurality of them may be arranged between the two.

(Configuration of print control device)
The configuration of the print control apparatus 202 of this embodiment is shown in FIG. In FIG. 2, a data input unit 201 inputs an image to be printed, character data, and the like. The print control device 202 controls the printing device 203. The printing apparatus 203 is the printer described with reference to FIG.

  The data storage unit 301 is a memory that holds data input from the image data input unit 201. The print data transmission unit 302 sends the data stored in the data storage unit 301 to the printing apparatus 203. The printed sheet count unit 303 counts the quantity of print data sent from the print data transmission unit 302 to the printing apparatus 203, for example, with the page unit in the print job as the quantity. A transport motor control unit 304 controls a motor that transports the recording medium in the printing apparatus 203. The head state analysis unit 305 analyzes states such as undischarge nozzles and nozzle temperatures of an inkjet head provided in the printing unit 108 in the printing apparatus 203. The maintenance determination unit 306 determines whether maintenance (discharge state adjustment processing) is necessary from the state of the head and the number of printed sheets. The maintenance parameter storage unit 307 stores information related to head maintenance, such as the number of pages in a print job that can be stably ejected by the head being used without maintenance, and a head temperature threshold value. The maintenance time setting unit 308 refers to the maintenance parameter storage unit 307 for the time required for maintenance according to the type of maintenance such as preliminary ejection, non-discharge detection, and non-discharge recovery based on the determination result of the maintenance determination unit 306. Set. A maintenance control unit 309 controls maintenance according to outputs from the maintenance determination unit 306 and the maintenance time setting unit 308. The maintenance signal transmission unit 310 issues a discharge command corresponding to, for example, a preliminary discharge nozzle. The head monitoring unit 311 sends the output value of the temperature sensor of the head included in the printing unit 108, for example, the nozzle, to the head state analysis unit 305. The conveyance motor operation unit 312 operates a rotary motor provided in the recording medium supply unit 101, the recording medium winding unit 103, the recording medium conveyance units 104 to 107, and the like of the printing apparatus 203. Each unit may be controlled by one or more CPUs that control the entire apparatus.

(Print control flow)
FIG. 3 is a diagram illustrating print control for high-speed printing on continuous paper in the present embodiment.

  First, in step S <b> 301, data such as images and characters to be printed and the number of outputs input by the data input unit 201 are stored in the data recording unit 301. The printing operation is started by this data input operation, and the process proceeds to the subsequent step.

  Next, in step S302, it is determined whether maintenance is necessary according to the state of the printing unit 108 at the start of printing. Specifically, at the start of printing, the temperature of each nozzle of the inkjet head provided in the printing unit 108 is read by the head monitoring unit 311 and sent to the head state analysis unit 305. In general, since the temperature of nozzles that are not performing printing operations is low, in order to discharge stably, preliminary discharge operation is performed for all nozzles, and the nozzles are heated to a temperature that provides stable discharge. It is better to raise the temperature. In addition, since the temperature of the head that can be stably ejected varies depending on parameters such as the material of the head and the ejection method, this parameter is stored in the maintenance parameter storage unit 307, read by the maintenance determination unit 306, and preliminarily ejected. Determine if action is required. If it is determined in step S302 that maintenance is necessary, the process proceeds to step S307. If it is determined that maintenance is not necessary, the process proceeds to step S303.

In step S <b> 303, the print data transmission unit 302 sends the print image data stored in the data storage unit 301 to the printing unit 108. The sent image data is used as a signal for ejecting ink from the ink jet head provided in the printing unit 108. Further, the conveyance motor control unit 304 sends an instruction for setting the conveyance speed to the normal printing speed (V _p ) to the conveyance motor operation unit 312, and the printing apparatus 203 controls the recording medium 102 to be conveyed by the conveyance motor operation unit 312. The printing unit 108 outputs an image. The number of image data output here (corresponding to the number of printed sheets) is not necessarily one. In other words, it may be output in arbitrary units such as 2, 10 and 100 sheets. When step S303 ends, the process proceeds to step S304.

  In step S304, the number of image data output in step S303 is counted by the printed sheet count unit 303. The counted number of printed sheets is transmitted to the maintenance determination unit 306 in later processing.

  Next, in step S305, it is determined whether or not the data transmitted in step S303 has reached the number of outputs in the print data acquired in step S301. If the number of outputs has not been reached, the process proceeds to step S306. If the number of outputs has been reached, the series of operations is terminated.

  In step S306, the maintenance determination unit 306 determines whether maintenance of the inkjet head is necessary during printing. Unlike the determination made in step S302, the determination made here is determined from the variation in the temperature of each nozzle obtained from the head state analysis unit 305 and the continuous print number obtained from the print number counting unit 303. . Note that there are two types of maintenance determined in step S306, preliminary ejection and non-discharge detection, and details of determination of each maintenance type will be described in detail below.

<Preliminary ejection determination>
Preliminary ejection, as described in step S302, suppresses a phenomenon in which an edge of an image is cut and a streak that occurs when ink is not ejected from a nozzle whose ejection signal is turned on. The cause is that the temperature of the nozzle that has not ejected ink or the number of ejections has decreased so far, especially in the method of heating and vaporizing ink rapidly, the temperature of the nozzle increases when the ejection signal is turned ON. It is mentioned that bubbles are not generated. On the other hand, when the temperature of the nozzle rises too much, the discharge is unstable, and in particular, the discharge amount may increase.

  Therefore, in order to reduce the uneven temperature of the nozzle, it is necessary to eliminate the uneven temperature of the nozzle by actively using the nozzle having a low temperature and resting the nozzle having a high temperature when performing preliminary discharge. The same applies to a method using a piezoelectric element (piezo element) that generates mechanical strain by application of a voltage because the operation of the element may not be stable.

  Therefore, in this determination, the necessity of preliminary ejection is determined by analyzing the temperature of each nozzle sent from the head monitoring unit 311 to the head state analyzing unit 305 before or during printing.

As the determination method, any one or more of the following methods are used. FIG. 4 is a graph in which the temperature of each nozzle sent to the head state analysis unit 305 is plotted on the vertical axis in the order of nozzles. T _H indicates the highest temperature among the nozzles forming the nozzle row, and T _L indicates the lowest temperature. In addition, I _H represents the ID of the nozzle having the highest temperature among the nozzles forming the nozzle row, and _TL represents the ID of the nozzle having the lowest temperature.

<Determination method 1>
When _TL is lower than an arbitrary threshold set in the maintenance parameter recording unit 307, even if the discharge signal is ON, there is a high possibility that a discharge failure will occur, and preliminary discharge is performed to raise the temperature from a low temperature nozzle. There is a need. Therefore, the maintenance determination unit 306 determines that preliminary ejection is necessary.

<Determination method 2>
If any greater than a threshold difference of T _L and T _H is set to a maintenance parameter recording unit 307, it is likely that the amount of ink ejected from the nozzle by high and low temperature changes. The higher the temperature is, the more the amount of ink ejected from each nozzle changes. As a result, unevenness in the density of the output image surface occurs, resulting in a reduction in image quality. For this reason, it is necessary to increase the temperature from the low temperature nozzle by performing preliminary ejection, while lowering the temperature of the high temperature nozzle by stopping the high temperature nozzle to relatively reduce the temperature unevenness. Therefore, the maintenance determination unit 306 determines that preliminary ejection is necessary.

<Determination method 3>
When the distance between I _L and I _H is larger than an arbitrary threshold set in the maintenance parameter recording unit 307, the temperature unevenness between the nozzles causes the density unevenness of the image, and the dark print and the light print The closer the distance to the nozzle, the more noticeable. That is, corresponding to the distance of the print image from the distance of I _L and I _H, the distance between I _L and I _H are higher density unevenness is conspicuous near, it is necessary to perform preliminary ejection in the same manner as described above. Therefore, the maintenance determination unit 306 determines that preliminary ejection is necessary when the distance is shorter than a predetermined value.

  As described above, in this determination method, it is determined whether maintenance processing is necessary based on the relationship between the nozzle and the temperature. Although FIG. 4 shows an example of a single-row nozzle array, a multi-row nozzle array may be used. In this case, the relationship between the temperature and the nozzle is generated three-dimensionally.

<Determination of undischarge detection>
Whether or not undischarge detection is necessary is determined based on whether or not the number of printed output sheets counted by the print sheet count unit 303 is larger than an arbitrary threshold value set in the maintenance parameter recording unit 307. If it is larger, undischarge detection is performed.

  First, if it is determined in step S306 that maintenance is not necessary, the process returns to the image data output flow in step S303. If it is determined that maintenance is necessary, the process proceeds to step S307.

  In step S307, the inkjet head maintenance process is executed. FIG. 5 shows a detailed flow of the maintenance process executed in step S307. Hereinafter, the description will be continued according to the flow shown in FIG.

  First, in step S501, it is determined whether or not undischarge detection is determined to be necessary in step S306. If it is determined that it is necessary, the process proceeds to S502, and if it is determined that it is not necessary, The process proceeds to step S508.

  In step S502, undischarge detection is executed. The undischarge detection performed here is implemented using a known technique, but a simple mounting method will be described with reference to FIG. In FIG. 6, the inkjet head 601 is provided in the printing unit 108. A light source 602 is a light source for use in non-discharge detection, and a sensor 603 receives light from the light source 602. As in the example shown in FIG. 6, when ink dots are ejected from the inkjet head 601, it can be seen that ink dots are ejected to block light reaching the sensor 603 from the light source 602. Therefore, by repeating the ejection of ink dots and the sensing by the sensor 603 in order from each nozzle provided in the inkjet head 601, it is possible to know which nozzles are not ejecting simultaneously with the detection of nozzle ejection failure.

  Here, for the sake of explanation, an example of an inkjet head including a single-row nozzle array that can be expressed in FIG. 6 is shown, but the nozzle array may have multiple rows. In that case, what is necessary is just to make it a structure provided with a light source and a sensor in each row | line | column. In addition, if it is a discharge opportunity once for each nozzle, there may be a discharge failure due to a drop in the temperature of the nozzle. Therefore, it is desirable to try detection multiple times for a nozzle determined to be a discharge failure. In that case, it is desirable not to inadvertently increase the number of head recovery operations that require processing time. The result of non-discharge detection in step S502 is sent to the step S503 for later processing.

  Next, in step S503, it is determined whether or not nozzle recovery is necessary based on the non-discharge detection executed in step S502. If undischarge is detected and nozzle recovery is necessary, the process proceeds to step S504, and if nozzle recovery is not necessary, the process proceeds to step S508.

  In step S504, the time required for the nozzle recovery operation to be performed later is set. Specifically, a time required for processing for removing bubbles in the nozzle in the nozzle recovery operation is stored in advance in the maintenance parameter recording unit 307, and the time is called by the maintenance time setting unit 308. When step S504 is completed, the process proceeds to step S505.

In step S505, a motor control signal to be transmitted to the transport motor control unit 304 is generated according to the time set in step S504. A specific motor control signal will be described with reference to FIG. In the graph of FIG. 7, the horizontal axis represents time, and the vertical axis represents the conveyance speed of the recording medium. In the figure, set at S504, the maintenance separated on the time axis the time (from T _MS to T _ME), the conveying speed of the paper is slower maintenance execution than the velocity (V _P) at the time of normal printing It is controlled to the hourly speed (V _M ). In this way, the amount of recording medium that is consumed at the normal printing speed when performing maintenance can be reduced by setting the conveyance speed during the maintenance period to be lower than that during printing. Is possible. Also, for example, as shown in FIG. 7B, it is not necessary to determine the maintenance speed (V _M ) shown in FIG. 7A, and it is only necessary to be able to control at a slower speed than during normal printing when performing maintenance. That is, control may be performed so that the speed gradually decreases from the normal printing speed, and after the predetermined speed is reached, gradually returns to the normal printing speed as the maintenance process ends. Here, the maintenance time refers to the period from T _MS to T _ME, at the time of completion of the maintenance for the paper at a rate of normal printing (V _P) is conveyed, the printing process immediately after completion of maintenance is resumed The

  Next, in step S506, nozzle recovery is performed. The nozzle recovery performed here is performed, for example, using a well-known method such as bringing a cap into close contact with the nozzle row and removing internal bubbles using a suction mechanism. Here, since the time required for suction and the time required for maintenance processing such as cap and wipe differ depending on the device configuration to be mounted, the required time is stored in the maintenance parameter recording unit 307 in advance.

  In step S507, the number of prints counted by the print number counting unit 303 is reset to zero.

  Next, step S508, which is performed when it is determined in step S501 or step S503 that no discharge failure detection or nozzle recovery is necessary, will be described.

  In step S508, it is determined whether or not preliminary ejection is necessary in step S306. An efficient determination is made by referring to the graph relating to the temperature of the head referenced in step S306. A broken line parallel to the horizontal axis shown in FIG. 8 indicates a temperature at which the inkjet head stably moves or its allowable range, and is stored in the maintenance parameter recording unit 307 in advance. If the head temperature is within this range, preliminary ejection is unnecessary, and if the temperature is below the range, preliminary ejection is necessary. If preliminary ejection is necessary, the process proceeds to step S509. If not necessary, the maintenance operation is terminated.

  In step S509, preliminary ejection data is generated. In the preliminary discharge data generation here, priority is given to the nozzle having the lowest temperature shown in the figure, and it is lower than the temperature arbitrarily determined between the temperature at which the inkjet head moves stably and its lower limit value. Preliminary ejection data is created for all nozzles at temperature. The number of dots in the preliminary ejection data can be obtained by referring to the relationship between the number of ejections and the amount of heat stored in the nozzles in advance and storing it in the maintenance parameter recording unit 307, although not particularly shown. . The obtained data signal is sent from the maintenance signal transmission unit 310 to the printing unit 108 later.

Next, in step S510, a time required for preliminary ejection is set. Specifically, the time required for the preliminary ejection data printing for the minimum temperature nozzle that requires heat storage that takes the most time for preliminary ejection to be printed by the printing unit 108 is calculated and set. Further, if the determination method 2 (the difference between T _L and T _H are cases greater than any threshold value set in the maintenance parameter recording unit 307) is used in step S306, the heat radiation of the nozzle to be heat dissipation (pause) time Set further. Specifically, the time required for the nozzle having the highest temperature among all nozzles to reach a temperature arbitrarily determined between the temperature at which the inkjet head moves most stably and its upper limit value is calculated and set. . Here, although not specifically shown, the pause time can be calculated by checking the relationship between the time and the heat radiation amount of the nozzle in advance, storing it in the maintenance parameter recording unit 307, and referring to the relationship. It is. Moreover, downtime also determine how 3 (when the distance I _L and I _H is greater than the arbitrary threshold value set in the maintenance parameter recording unit 307) is calculated. In addition, the larger one of the time required for actually discharging dots and the time required for heat dissipation is set as the preliminary discharge time.

  In step S511, as in step S505, a signal is generated so that the motor is controlled at a speed lower than the printing speed during the preliminary ejection time as shown in FIG. 7A or 7B.

  If preliminary discharge is necessary, preliminary discharge is executed in step S512. The preliminary ejection performed here is performed based on the dot ON / OFF signal generated in step S509. If it is determined in step S510 that the pause time is longer, all operations are paused until the preliminary discharge time comes.

  With the above processing, the processing in step S307 ends.

  The present invention also provides a storage medium storing a program code of software for realizing the functions of the above-described embodiments (for example, the processing shown by the flowchart in which the processing of each unit described above is associated with each step). It can also be realized by supplying to. In this case, the functions of the above-described embodiments are realized by the computer (or CPU or MPU) of the system or apparatus reading and executing the program code stored in the storage medium so that the computer can read the program code.

  In the first embodiment, the method of adjusting the paper transport speed based on the signal indicating whether or not to enter the maintenance mode has been described, but the present invention is not limited thereto. In a printer capable of high-speed printing, there is an adjustment time until switching of a print job controlled for each print image and stopping of the paper after printing is completed. That is, the maintenance process can be performed at a speed (speed adjustment) that is not the conveyance speed at the time of original printing during the conveyance of the print medium.

Maintenance during speed adjustment will be described with reference to FIG. In FIG. 9A, the print speed is adjusted from V _P1 to V _P2 when the print job is switched. Here, since there is a time for adjusting from VP1 to VP2, the same processing as the maintenance executed in steps S506 and S512 is performed every time the time is generated. The maintenance executed here is not described in detail because it is the same processing as described above. After execution of step S506, the print number counting unit 303 resets the continuous print number in step S507. Further, the shown in FIG. 9 (b), the paper conveying speed after the completion of printing to the V _S so from V _P, shows an example of using the maintenance time to stop. In this way, it is possible to reduce maintenance time during original printing.

  In the above embodiment, the printing apparatus and the printing control apparatus that controls the printing apparatus are described separately. However, a printing system in which the printing apparatus executes the functions of the printing control apparatus may be used.

  In the above embodiment, the content of the maintenance process is different between step S302 and step S306. However, in order to prioritize securing the printing bottom, it may be performed as a single maintenance process. May be performed.

Claims (10)

A printing system that controls a printing apparatus that performs printing using a plurality of discharge nozzles arranged over at least the width of a continuously conveyed printing medium,
Adjusting means for adjusting the discharge state of the discharge nozzles during conveyance of the print medium;
When the adjustment process by the adjustment unit is performed, a control unit that performs control to reduce a conveyance speed at which the print medium is conveyed;
A printing system comprising:   The printing system according to claim 1, wherein the adjustment process includes at least one of a preliminary discharge process and a discharge failure detection process of the discharge nozzle.   The printing system according to claim 1, wherein the conveyance speed is set to a conveyance speed that is lower than that of normal printing during the adjustment process.   4. The apparatus according to claim 1, wherein the adjustment unit further includes a determination unit that determines whether the adjustment process is necessary according to temperatures of the plurality of ejection nozzles at the start of printing. The printing system according to item.   5. The printing system according to claim 4, wherein the adjustment unit performs an adjustment process of increasing a temperature from a nozzle of which the temperature is determined to be low by the determination unit among the plurality of ejection nozzles.   6. The printing according to claim 4, wherein the adjustment unit performs an adjustment process of stopping the discharge of the nozzles determined to have a high temperature by the determination unit among the plurality of discharge nozzles. system.   The determination unit determines that the adjustment process is necessary when a distance between a nozzle determined to be high by the determination unit and a nozzle determined to be low is shorter than a predetermined value among the plurality of discharge nozzles. The printing system according to any one of claims 4 to 6, wherein:   The said adjustment means further has a determination means to determine whether the said adjustment process is required according to the number of the print jobs with respect to the said printing medium, The Claim 1 thru | or 7 characterized by the above-mentioned. Printing system. A printing method for controlling a printing apparatus for printing using a plurality of discharge nozzles arranged at least for the width of a printing medium that is continuously conveyed,
An adjusting step in which the adjusting means adjusts the discharge state of the discharge nozzles during conveyance of the print medium;
A control step in which the control means performs control to reduce the conveyance speed at which the print medium is conveyed when the adjustment process by the adjustment step is performed;
A printing method characterized by comprising:   A program that causes a computer to function as each unit of the printing system according to any one of claims 1 to 8.

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