JP2019136900A - Inkjet recording device - Google Patents

Abstract

To provide an inkjet recording device in which ink dots caused by on-paper preliminary discharge are suppressed to be less conspicuous.SOLUTION: An inkjet recording device (100) includes: a recording head (105) which is provided with a plurality of nozzles discharging ink, and performs recording on a recording medium conveyed in a prescribed conveyance direction by discharging ink from the nozzles; and controlling means (201) which determines, in preliminary discharging ink not contributing to the recording from the nozzles onto the recording medium, an interval (Offset and Count) of the preliminary discharge on the basis of a length (P) of the recording medium (101b) in the conveyance direction (A).SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that performs preliminary ink ejection on a recording medium in order to maintain ink ejection performance of a recording head.

  2. Description of the Related Art Conventionally, in order to maintain the ink ejection performance of a recording head, an ink jet recording apparatus having a paper surface preliminary ejection function for performing preliminary ejection, which is ink ejection that does not contribute to recording, is known. In such an ink jet recording apparatus, when paper feeding is delayed due to the occurrence of paper feeding failure and the paper feeding interval is widened, it becomes impossible to perform preliminary paper ejection on the recording medium. For this reason, in this case, moisture evaporation proceeds to the ink in the nozzles, the ink is thickened, and the ink ejection performance of the recording head is lowered.

  As an example of a conventional technique for solving this problem, for example, in the ink jet recording apparatus described in Patent Document 1, a non-ejection time (non-ejection time) between sequentially supplied first recording paper and second recording paper. ) Is used to control the timing of preliminary paper ejection onto the recording paper. In this way, by controlling the timing of pre-ejection on the recording sheet according to the length of the non-ejection time, the ink jet recording apparatus of Patent Document 1 reduces the decrease in ink ejection performance of the recording head. Yes.

Japanese Patent Laid-Open No. 2015-9388

  By the way, as a recording medium used in an ink jet recording apparatus, a label sheet for the purpose of creating a distribution / delivery label, a food display label, or the like is generally known. The label paper is obtained by temporarily attaching a plurality of labels having a predetermined size at a certain interval to a mount called release paper. When recording is performed on this label sheet, since the ink receiving layer is not provided on the surface of the release paper between the labels in the sheet conveyance direction, it is impossible to perform preliminary paper ejection on this part.

  Therefore, when recording is performed on the label paper in the conventional inkjet recording apparatus described in Patent Document 1, the non-ejection time for the part of the release paper between the first label and the second label temporarily attached on the label paper is reduced. The timing of preliminary ejection on the recording sheet is controlled according to the length. In the conventional inkjet recording apparatus, the number of nozzles used for preliminary ejection as the non-ejection time becomes longer at the rear end portion of the first label and the front end portion of the second label in the conveyance direction of the label paper. Is increased so as to perform preliminary paper ejection. In this case, ink is ejected so that more dots are formed as the non-ejection time is longer at the rear end portion of the first label and the front end portion of the second label where the preliminary ejection is performed. Is done. As a result, in the conventional ink jet recording apparatus, in particular, ink dots due to preliminary ejection on the paper surface become conspicuous in the white portion of the label (the portion without print data), and the recording quality may be deteriorated.

  Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of suppressing the conspicuousness of ink dots due to preliminary ejection on the paper surface.

An ink jet recording apparatus according to the present invention includes:
A recording head that has a plurality of nozzles for discharging ink and performs recording by discharging ink from the nozzles to a recording medium that is transported in a predetermined transport direction;
Control means for determining the preliminary ejection interval based on the length of the recording medium in the transport direction in preliminarily ejecting ink that does not contribute to recording from the nozzle to the recording medium;
It is characterized by having.

  According to the present invention, it is possible to provide an ink jet recording apparatus that can suppress the conspicuousness of ink dots due to preliminary ejection on a paper surface.

1 is a schematic configuration diagram of an inkjet recording apparatus according to an embodiment of the present invention. It is a block diagram which shows schematic structure of the control system of an inkjet recording device. It is a flowchart which shows the control for suppressing the conspicuousness of the dot of the ink formed on a label by paper surface preliminary discharge. It is a table which shows the example of the required discharge period per nozzle according to temperature and humidity. It is a table which shows the example of a paper surface preliminary discharge parameter. It is a figure which shows the example of the dot pattern of the ink of paper surface preliminary discharge.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus (hereinafter simply referred to as a recording apparatus) 100 according to an embodiment of the present invention. The inkjet recording apparatus 100 according to the present embodiment is supplied with a label sheet 101 in which a plurality of adhesive labels (hereinafter simply referred to as labels) are temporarily attached to a mount called release paper and wound in a roll shape as a recording medium. . The label sheet 101 is conveyed at a constant speed in the conveying direction indicated by an arrow A in the figure as the conveying roller 102 rotates. The rotation of the transport roller 102 is controlled by driving the transport motor 103.

  Here, the labels on the label paper 101 are arranged in a line at predetermined intervals in the transport direction of the label paper 101. Below, the distance (length) of the release paper portion where the ink receiving layer between the labels in the transport direction is not provided is the gap length, and the distance (length) of the label where the ink receiving layer is provided in the transport direction Is called the print length. In other words, in the conveyance direction of the label sheet 101, the distance (length) at which the paper surface preliminary ejection cannot be performed is the gap length, and the distance (length) at which the paper surface preliminary ejection can be performed is the printing length.

  During the conveyance of the label sheet 101, the leading edge of each label is detected by the sheet detection sensor 104 provided in the conveyance path. Using the detected position of the leading edge of each label as a reference (reference position), ink is ejected from a plurality of ink jet recording heads (hereinafter also simply referred to as recording heads) 105K, 105C, 105M, and 105Y to each label. The In other words, when the label paper 101 passes under the recording heads 105K, 105C, 105M, and 105Y, the ink is ejected from the nozzles of the recording head based on the reference position of each label detected previously, thereby the label paper 101. Images are recorded on each label above. A transport encoder 110 is connected to the transport path of the label paper 101, and the transport position of the label paper 101 on the transport path is detected by the output of the transport encoder 110. When rewinding the label paper 101, a roll motor 111 is used.

  The inkjet recording heads 105K, 105C, 105M, and 105Y are recording heads for ejecting black, cyan, magenta, and yellow inks, respectively, and can record a color image with these inks. Since the plurality of inkjet recording heads 105K, 105C, 105M, and 105Y have a common configuration, they are also collectively referred to as an inkjet recording head (or simply, a recording head) 105 for convenience of explanation. The recording head 105 is a long line head having a recording width corresponding to the maximum width of the label sheet 101, and a plurality of nozzles for ejecting ink are arranged on the bottom side surface thereof. The plurality of nozzles are arranged so as to form a nozzle row along a direction (in the present embodiment, a direction orthogonal) intersecting the conveyance direction of the label sheet 101 indicated by an arrow A in the drawing. In the vicinity of the bubbling chamber communicating with each nozzle of the recording head 105, an electrothermal conversion element (heater), a piezoelectric element, or the like that generates energy for discharging the ink supplied to the recording head from the discharge port at the tip of the nozzle. The discharge energy generating element is provided. When the electrothermal conversion element is provided, the ink in the foaming chamber is foamed by the heat generation, and the ink can be ejected from the ejection port at the tip of the nozzle using the foaming energy.

  Below the recording head 105, a capping mechanism 107 having a function of capping the discharge port at the tip of the nozzle is provided. The capping mechanism 107 is used for capping the nozzle discharge port during recovery operation and power-off performed in order to maintain a good ink discharge state of the print head, and is used for each print head 105K, 105C, 105M, and 105Y. Correspondingly provided individually. In the recording apparatus 100, the recording head 105 includes a recording position for recording an image on a recording medium, a recovery position for performing a recovery operation, and a capping position that is an arrangement position when the power is turned off. It is configured to be movable. Further, the recording head 105 and the capping mechanism 107 are configured to be capable of relative movement in the left-right direction in FIG. The recovery operation includes suction recovery in which the ink in the recording head 105 is sucked into the capping mechanism 107 from the nozzle, and pressurization in which the ink in the recording head is discharged from the nozzle into the capping mechanism 107 by pressurizing the recording head 105. Recovery. Further, the preliminary operation for discharging ink from the nozzles of the recording head 105 into the cap (not shown) of the capping mechanism 107 is also included in the recovery operation.

  In the upper part of the recording apparatus 100, ink tanks 106K, 106C, 106M, and 106Y for storing respective inks supplied to the recording heads are provided corresponding to the recording heads 105K, 105C, 105M, and 105Y.

  A computer device (host device) 108 is connected to the recording device 100. The recording apparatus 100 records an image based on the recording data input from the external computer apparatus 108.

  Next, the configuration of the control system of the inkjet recording apparatus 100 of the present embodiment will be described.

  FIG. 2 is a block diagram illustrating a schematic configuration of a control system of the inkjet recording apparatus 100. The inkjet recording apparatus 100 includes a CPU (central processing unit) 201, an interface controller 203, a program ROM 202, and the like as a control system for controlling the recording mechanism including the recording head 105 described above. The CPU 201 (corresponding to the control means of the present invention) executes a program stored in the program ROM 202 and controls the respective units of the recording apparatus 100 in an integrated manner. A program ROM 202 stores programs and data for controlling the recording apparatus 100.

  The recording data transmitted from the computer apparatus 108 is received by the CPU 201 via the interface controller 203 of the recording apparatus 100. In addition, commands for instructing the gap length between labels of the label sheet 101 as a recording medium, the label printing length, the number of labels, the type of label (matte, gloss, etc.), etc. are also received by the CPU 201 via the interface controller 203. Is done. In addition to command analysis, the CPU 201 executes arithmetic processing for controlling overall operations of the recording apparatus 100 such as reception of recording data, recording operation, and handling of the recording medium. When executing this processing, the work RAM 204 is used as a working memory.

  The EEPROM 205 is a rewritable nonvolatile memory. The EEPROM 205 includes a correction value for finely adjusting (vertical registration adjustment) the time when the previous recovery operation was performed, the distance between a plurality of recording heads, and the recording position on the recording medium in the transport direction. The unique parameters of the recording apparatus 100 are stored.

  When the CPU 201 receives a command and print data from the computer apparatus 108 via the interface controller 203, the CPU 201 analyzes the command and then stores the image data of each color component of the print data in the image memory 206 by developing a bitmap.

  When recording (printing) an image, the CPU 201 drives the head motor 210 via the output port 207 and the motor drive circuit 208 to move the recording head 105 to a recording position for recording the image. When the movement of the recording head 105 to the recording position is completed, the CPU 201 drives the conveyance motor 103 via the output port 207 and the motor drive circuit 208 to rotate the conveyance roller 102. The rotation of the transport roller 102 causes the label paper 101 to be transported at a constant speed. The CPU 201 detects the leading edge of each label using the paper detection sensor 104 in order to determine the recording timing for each label on the label paper 101 conveyed at the constant speed. A detection signal of the paper detection sensor 104 is input to the CPU 201 via an input / output circuit (I / O) 211. As the label sheet 101 is transported, a signal indicating the transport position of the label sheet 101 is output from the transport encoder 110. This output signal is input to the CPU 201 via the input / output circuit (I / O) 211. When the CPU 201 sequentially reads out the image data for each color component from the image memory 206 in synchronization with the signal indicating the transport position of the transport encoder 110, the CPU 201 controls the recording head 105 corresponding to the color with the read data. Transmit via circuit 212. Accordingly, ink of each color is selectively ejected from the nozzles of the recording heads 105K, 105C, 105M, and 105Y based on the transmitted image data, whereby an image is recorded on each label on the label paper 101. .

  Further, the CPU 201 performs a recovery operation or the like via the output port 207 and the motor drive circuit 208, and a capping motor 209 for moving the capping mechanism 107 and a head motor 210 for moving the recording head 105. To control.

  Further, when rewinding the label paper 101, the CPU 201 controls the roll motor 111 via the output port 207 and the motor driving circuit 208 to perform the rewinding.

  The rotation of the pump motor 213 is controlled by the CPU 201 via the output port 207 and the motor drive circuit 208. The pump motor 213 is driven when ink is supplied to the recording head 105.

  An operation panel 214 as a user interface is connected to the CPU 201 via an input / output circuit (I / O) 215. By operating the operation panel 214, the user can make settings for the recording apparatus 100.

  The recording apparatus 100 is provided with a temperature / humidity sensor 216 for detecting the ambient temperature and humidity in the recording apparatus, and a detection signal output from the temperature / humidity sensor 216 is sent to the CPU 201 via the A / D converter 217. Is input.

  Next, control of the features of the present invention for suppressing the conspicuousness of the ink dots formed on the label by the preliminary ejection on the paper will be described with reference to the flowchart of FIG. Note that the program related to this control is stored in advance in the program ROM 202 and is repeatedly executed at predetermined time intervals by the CPU 201 after the activation of the inkjet recording apparatus 100 is completed.

  In step S <b> 101, the CPU 201 determines whether there is recording data received from the computer apparatus 108. If the received recording data is present, the CPU 201 proceeds to step S102 (Yes side). On the other hand, if there is no received recording data, the CPU 201 ends this control (No side).

  In step S102, the CPU 201 analyzes the command received from the computer apparatus 108 together with the recording data, and obtains the gap length G (mm), the printing length P (mm), and the transport speed T (mm / s) of the label paper. To do. In the ink jet recording apparatus 100 of the present embodiment, the gap length is preferably 9.5 mm or less, and the printing length is preferably 8 mm or more.

  In step S <b> 103, the CPU 201 detects the ambient temperature and humidity in the recording apparatus 100 using the temperature / humidity sensor 216. Then, the CPU 201 searches the table shown in FIG. 4 using the detected temperature (° C.) and humidity (%) as keys, so that a plurality of nozzles constituting the nozzle array of the recording head are necessary for each nozzle. The discharge cycle C (sec) is determined.

  Here, the necessary ejection cycle means a cycle (time interval) in which ink should be preliminarily ejected from the nozzles in order to prevent printing defects due to thickened ink. For example, in an environment where the temperature and humidity are low, the viscosity of the ink is high and the ink is more easily dried. Therefore, in this case, the necessary ejection cycle per nozzle is shortened to discharge the ink in the nozzle. This suppresses the increase in ink viscosity and suppresses a decrease in ink ejection performance of the recording head. On the other hand, in an environment where the temperature and humidity are high, the ink has a low viscosity and is difficult to dry. For this reason, in this case, it is difficult to increase the viscosity of the ink, and there is little possibility that the ink ejection performance of the recording head is lowered. Therefore, the necessary ejection cycle per nozzle can be lengthened.

  In step S104, the CPU 201 obtains the gap length G (mm) and the print length P (mm) of the label paper acquired as described above and the necessary ejection cycle C (sec) per nozzle determined as described above using the equation (1). ) To calculate the paper preliminary ejection time X (sec).

  The paper preliminary ejection time X (sec) is a time indicating that the ink in all the nozzles should be discharged within the paper preliminary ejection time for a plurality of nozzles constituting the nozzle row of the recording head, and the gap length It depends on the ratio between G (mm) and printing length P (mm). For example, when a label sheet having a long gap length G (mm) and a short print length P (mm) is used, the time during which the paper surface preliminary discharge cannot be performed becomes long. A short value of is calculated. In this case, in order to discharge the ink in all the nozzles of the recording head within the paper preliminary discharge time X (sec), it is necessary to shorten the average discharge cycle per nozzle and perform the paper preliminary discharge. is there. On the other hand, when a label sheet having a short gap length G (mm) and a long print length P (mm) is used, the time during which the paper surface preliminary discharge can be performed becomes long. Long values are calculated. In this case, the ink in all the nozzles of the recording head is discharged within the paper preliminary discharge time X (sec) even if the average paper discharge period per nozzle is lengthened and paper preliminary discharge is performed. Can do.

  Next, in step S105, the CPU 201 determines a paper surface preliminary discharge parameter based on the transport speed T (mm / s) acquired in step S102 and the paper surface preliminary discharge time X (sec) calculated in step S104.

  The paper preliminary ejection parameter is a numerical value of the ink ejection pattern in the preliminary paper ejection. Each table in FIG. 5 shows an example of the paper surface preliminary ejection parameters when the conveyance speed T is 200 mm / s. The parameter determination method will be described with reference to FIG. 5. When the paper preliminary ejection time X (sec) is less than 1 second (X <1), “X = 0. The table (a) of “5 sec” is adopted, and its contents are determined as the paper surface preliminary ejection parameters. When the paper preliminary ejection time is 1 second or more and less than 5 seconds (1 ≦ X <5), the table (b) of “X = 1 sec” is set to 5 seconds or more and less than 10 seconds (5 ≦ X <10). In this case, the table (c) of “X = 5 sec” is adopted, and the content is determined as the paper surface preliminary ejection parameter. When the paper preliminary ejection time is 10 seconds or more (10 ≦ X), the table (d) of “X = 10 sec” is adopted, and the content is determined as the paper preliminary ejection parameter. Since the content of the paper surface preliminary ejection parameter differs for each conveyance speed, it is necessary to appropriately determine the parameter for each conveyance speed by a method described later. The paper surface preliminary discharge parameter is provided for each time range as described above of the paper surface preliminary discharge time X (sec).

  When recording is performed on only one label, the gap length G (mm) may be set to zero.

  Hereinafter, the paper preliminary ejection parameters will be described in detail.

  The paper preliminary ejection parameter is used to determine the dot interval at which ink is ejected when performing preliminary paper ejection, and is composed of two elements, “Offset” and “Count”. Yes. Offset indicates the ink discharge interval (dot interval) in the conveyance direction of the label paper. “Count” indicates the dot interval (ink discharge interval) in the nozzle row direction (nozzle arrangement direction) of the recording head. In either case, the unit is “dot”. These are the paper surface preliminary ejection parameter calculation methods, and Offset is calculated based on Equation (2).

  Hn is the number of nozzles of the recording head. In the ink jet recording apparatus 100 of the present embodiment, since the number of nozzles of each recording head 105K, 105C, 105M, and 105Y, Hn is 5184 nozzles. Hr is the opening size per nozzle. In this embodiment, Hr is 21.25 μm. D is a print length necessary for ink ejection of all nozzles (5184 nozzles in the present embodiment as described above). This D is calculated by equation (3).

  On the other hand, Count is calculated based on Expression (4).

  Hn is the number of nozzles of the recording head as described above.

  Next, in step S106, the CPU 201 generates dot pattern data of ink for preliminary paper ejection based on the paper preliminary ejection parameters determined in step S105. Then, when the CPU 201 reads out the image data of each color component of the recording data from the image memory 206, the CPU 201 combines the generated dot pattern data with the image data, and for each color of K, C, M, Y, for recording Create composite image data.

  In step S107, the CPU 201 performs recording (printing) on the label of the label paper 101 using the recording composite image data created in step S106 as recording data. As a result, an image of recording data including dot pattern data of ink for preliminary ejection on the paper surface is recorded on the label on the label paper. In this recording, ink is ejected from the recording heads 105K, 105C, 105M, and 105Y so as to form the same dot pattern on the label.

  FIG. 6 is a recording example of a dot pattern for preliminary ejection on the paper surface in the inkjet recording apparatus 100 of the present embodiment. In FIG. 6, paper surface preliminary ejection is performed from the recording head 105 (105K, 105C, 105M, 105Y) to the label 101b temporarily attached to the release paper 101a of the label paper 101. The ink dots 503 by preliminary ejection on the paper surface are formed such that the inks of the colors K, C, M, and Y are superimposed on one point (dot). For convenience of explanation, FIG. 6 shows only an ink dot pattern by preliminary ejection on the paper.

  The calculation of the above-mentioned paper preliminary ejection parameters Offset and Count is performed in order to arrange the dots 503 on the label (101b) at an inconspicuous interval.

  For example, when the paper preliminary ejection time X (sec) is 1 second or more and less than 5 seconds (1 ≦ X <5) and the conveyance speed T is 200 mm / s, in the present embodiment, for example, FIG. A value “2 (dot)” shown in the table (b) of “X = 1 sec” is calculated. Offset, as described above, determines the ink discharge interval (dot interval) in the conveyance direction of the label paper 101. Therefore, the dot 503 in FIG. 6 is an ink dot at a position shifted by 2 dots from the first ink ejection position in the next ink ejection following the first ink ejection on the paper surface in the transport direction of the label paper 101. The ink ejection is controlled so that the ink is disposed. That is, when the value of Offset is 2 dots, the first row of dots 503 is formed on the label 101b by the first ink ejection of the preliminary paper ejection. Then, the second dot 503 is formed at a position shifted (shifted) by 2 dots in the label sheet conveyance direction from the position where the first row dot 503 is formed on the label 101b by the next ink ejection. Is done. In this case, each row of ink dots is formed while leaving a gap of 1 dot in the conveyance direction of the label paper. Ink dot formation performed while shifting (shifting) this position in the label sheet transport direction is performed in the same manner for the third and subsequent dots 503.

  On the other hand, if it is Count but the paper preliminary ejection time and the conveyance speed are values as described above, in this embodiment, “Count = 1” shown in the table (b) of “X = 1 sec” in FIG. A value of “97 (dot)” is calculated. As described above, Count determines the dot interval (ink discharge interval) in the nozzle row direction of the recording head. For this reason, of the plurality of nozzles constituting the nozzle row, for example, when the nozzle located at the right end in the nozzle row direction is set as the starting point, the starting nozzle and the first dot as the first dot, the 97th dot in the left direction of the nozzle row The corresponding nozzle is determined as a target nozzle for preliminary ejection on the paper surface. Next, starting from the nozzle corresponding to the 97th dot, the next target nozzle for preliminary ejection on the paper surface is determined by the same procedure. Then, by repeating the above procedure for a plurality of nozzles constituting the nozzle row, all target nozzles for preliminary paper ejection are determined. By performing ink ejection from the target nozzles for preliminary ejection on the paper surface determined in this way, the dots 503 in FIG. 6 have 96 dots (==) in the first column in the transport direction in the nozzle column direction of the recording head. 97-1) It is arranged so as to be separated by dots. In the second row in the transport direction, the nozzle at the next position shifted (shifted) by 1 dot to the left of the nozzle row from the nozzle that is the starting point in the first row is determined as the target nozzle for pre-discharge on the paper. In the third and subsequent rows, the nozzle at the next position shifted by 1 dot in the left direction of the nozzle row from the nozzle that is the starting point in the previous row (second row in the case of the third row) is used as the target nozzle for preliminary ejection on the paper surface. And repeat this procedure until the Count-1 column. In this case, the process is repeated up to the 96th (= 97-1) th column. As a result, when preliminary paper ejection is performed, ink is discharged from all nozzles of the recording head. By performing ink ejection from the target nozzles for preliminary ejection on the paper determined as described above, the dots 503 in FIG. 6 are changed from the position of the first row of dots 503 from the position of the first row in the second row onward. Are arranged so as to shift by 1 dot in the left direction of the nozzle row of the recording head.

  As described above, when recording is performed on a label sheet with a conventional ink jet recording apparatus, the timing of preliminary ejection on the label sheet is controlled only in accordance with the gap length, which is the distance between the release paper portions between the labels. As the non-ejection time due to the gap length is longer, more dots are formed on the rear end portion of the label on which the paper surface preliminary ejection is performed and the front end portion of the label immediately following the label. Ink is discharged. Therefore, in the conventional ink jet recording apparatus, there is a possibility that the recording quality of the label is deteriorated due to the conspicuousness of the ink dots.

  On the other hand, in the ink jet recording apparatus of the present embodiment, the paper surface is taken into account according to the ratio between the gap length G (mm) and the printing length P (mm) of the label paper, taking into account the ambient temperature and humidity in the recording apparatus. The preliminary discharge time X (sec) is calculated. As described above, the paper preliminary ejection time X (sec) is a value indicating a time limit frame for discharging the ink in all the nozzles of a plurality of nozzles constituting the nozzle array of the recording head. Next, the calculated paper surface preliminary discharge time X (sec), the label paper conveyance speed T (mm / s), and the requirements of the nozzles provided in the recording head (number of nozzles, opening size) are calculated. Thus, the paper surface preliminary ejection parameters Offset and Count are calculated. Then, based on the calculated pre-discharge parameter for the paper surface, a dot pattern of ink for pre-discharge of the paper surface is generated. That is, in the ink jet recording apparatus of the present embodiment, not only the gap length that cannot be printed on the label sheet but also the print length that is the distance of the label that can be printed is taken into consideration. Then, according to the ratio between the gap length and the print length, ink dots for preliminary ejection on the paper surface are scattered so that the dots of the preliminary ejection on the paper surface are less noticeable with respect to the label in the printable area. Generate a dot pattern. By using this dot pattern, ink dots can be arranged on the label at an inconspicuous interval.

  Therefore, in the ink jet recording apparatus of the present embodiment, it is possible to suppress the conspicuousness of the ink dots due to the preliminary ejection on the paper surface, and therefore it is possible to suppress the deterioration of the recording quality of the label.

  In this embodiment, the case where a label is used as the recording medium has been described. However, the present invention can be applied to the case where a sheet such as a postcard is used as the recording medium. In this case, the print area length in the transport direction of the recording medium is defined as a print length P, and the distance from the rear end in the transport direction in the print area of the preceding recording medium to the front end in the transport direction in the print area of the subsequent recording medium is defined as the gap length G. And it is sufficient.

DESCRIPTION OF SYMBOLS 100 Inkjet recording device 101 Label paper 101a Release paper 101b Label 105 Recording head 201 CPU (control means)
A Label paper transport direction C Required ejection cycle (per nozzle)
G Distance between labels P Label length T Transport speed X Pre-discharge time on paper

Claims (3)

A recording head that has a plurality of nozzles for discharging ink and performs recording by discharging ink from the nozzles to a recording medium that is transported in a predetermined transport direction;
Control means for determining the preliminary ejection interval based on the length of the recording medium in the transport direction in preliminarily ejecting ink that does not contribute to recording from the nozzle to the recording medium;
An ink jet recording apparatus comprising: The control unit determines the preliminary ejection interval based on a distance from a rear end in a transport direction of a preceding recording medium to a front end in a transport direction of a recording medium that follows the preceding recording medium. 2. An ink jet recording apparatus according to 1. The ejection interval is determined based on an interval between nozzles that eject the preliminary ink in the nozzle arrangement direction and an interval that ejects the preliminary ink in the transport direction. The ink jet recording apparatus according to claim 1 or 2.