JP2013052627A - Apparatus and method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration of image quality caused by the satellite regardless of the size of the satellite, when forming an image in a recording medium by making a recording head that ejects the ink, opposing to the recording medium, reciprocating, and ejecting the ink from the recording head when moving in both of the going direction and the return direction.SOLUTION: When there are only the main droplets and no satellite, the ejection timing of the main droplets 101 and 102 are set so that the main droplets 101 and 102 ejected when the recording head are moving in the going direction and the return direction are disposed in the direction perpendicular to the movement direction of the recording head. When there are satellites 111 and 112, the right and left ends of the ruled line are assumed to be smooth lines L3 and L4, and L5 and L6 by optimally setting the reciprocating adjustment amount that is the amount to displace the ejection timing in moving in the returning direction to the ejection timing in moving in the going direction in consideration of the sizes of the satellites 111 and 112.

Description

  The present invention relates to an inkjet recording type image forming apparatus and an image forming method.

  Inkjet recording type image forming apparatuses usually have a recording head in which nozzle groups for ejecting ink are formed, a carriage mounted with the recording head and moving in a predetermined direction, and a sheet in a direction perpendicular to the carriage moving direction. And a recording medium conveying device for conveying a recording medium such as the above.

  When an image is formed on the recording medium, the recording medium is intermittently conveyed by the recording medium conveying device, and the nozzle is based on the image data while moving (scanning) the carriage in a predetermined direction while the conveyance is temporarily stopped. By repeating the operation of ejecting ink from the nozzle and forming an image on the recording medium facing the ink ejection port of the nozzle group, an image for one page is formed on the recording medium.

  In an ink jet recording type image forming apparatus, unintended minute droplets (= satellite) are generated along with intentionally ejected main droplets. Further, in the above-described serial ink jet recording type image forming apparatus, in order to increase productivity, so-called bi-directional printing is performed in which ink is ejected both during forward movement and during backward movement while reciprocating the recording head. I do.

  Here, since the satellite lands on the recording medium after the main droplet, the positional relationship between the main droplet and the satellite on the recording medium is reversed depending on the moving direction of the recording head. Accordingly, satellites adhere to both the left and right sides of the main droplet adhesion portion (= image data portion). That is, as shown in FIG. 10A, when moving in the right direction (when moving in the forward direction), the satellite 111 is attached to the right side of the main droplet 101, and when moving in the left direction as shown in FIG. 10B (when moving in the backward direction). ) Has a satellite 112 attached to the left side of the main droplet 102.

  For this reason, for example, when a vertical ruled line (printing direction of the recording medium) is printed, satellites attached to both the left and right sides cause the smoothness of the ruled line to be lost. This will be described with reference to FIG.

  When forming a vertical ruled line by bidirectional printing, as shown in FIG. 11A, the landing position of the main droplet 101 when moving in the forward direction and the landing position of the main droplet 102 when moving in the backward direction are orthogonal to the moving direction (scanning direction). The ejection timings in the forward direction and the backward direction are set so as to line up in the direction to perform.

  Here, when there is a satellite, as shown in FIGS. 11B and 11C, satellites 111 and 112 are generated on the right and left sides of the main droplets 101 and 102 due to the difference in the carriage scanning direction. FIGS. 11B and 11C show the satellites 111 and 112 with different sizes. FIG. 11B shows a small satellite and FIG. 11C shows a large satellite. Here, the dot diameters of the main drops 101 and 102 are 100 μm, the dot diameters of the satellites 111 and 112 are 30 μm in FIG. 11B, and 50 μm in FIG. 11C. The distance from the main droplets 101 and 102 to the corresponding satellites 111 and 112 was set to 70 μm.

  Originally, if printing is performed as shown in FIG. 11A, the left and right ends of the ruled lines become smooth lines L1 and L2. However, as shown in FIGS. 11B and 11C, when the satellites 111 and 112 are generated on the left and right, respectively, the states L11 to L14 are uneven at the left end and the right end of the ruled line, and the smoothness is lost.

As a technique for dealing with this problem, there is a printing apparatus described in Patent Document 1. The printing dots in this printing apparatus will be described with reference to FIG.
When satellites are generated for an object that requires smooth ruled lines as shown in FIG. 12A, as shown in FIG. 12B, the bidirectional discharge timing is adjusted so that the contour becomes smooth. I have to.

  Here, FIG. 12A is the same as FIG. 11A. As described above, in FIG. 11A, when satellites are generated, as shown in FIG. 11B, the left and right edges of the ruled line are uneven, and the smoothness is lost. Therefore, in the printing apparatus described in Patent Document 1, the reciprocal adjustment amount of the main droplets 101 and 102 is set to 35 μm. That is, the discharge timing at the backward movement is set 35 μm earlier than that in FIG. 11B with reference to the discharge timing at the forward movement. As a result, as shown in FIG. 12B, the left and right ends of the ruled lines become smooth lines L15 and L16. In other words, by making the satellite a part of the image, the satellite attached to the recording medium can be made inconspicuous, and as a result, deterioration in image quality can be suppressed.

  However, since the patent document 1 does not mention the size of the satellite, even if an appropriate reciprocation adjustment amount (35 μm) is set as shown in FIG. 12B for the satellite of the size shown in FIG. 11B, When the satellite is large as shown in FIG. 11C, the reciprocal adjustment amount (35 μm) in FIG. 12B may not be optimal as shown in FIG. 12C. In FIG. 12C, it becomes the state L17-L18 which became uneven at the left end and right end of a ruled line, and it does not become smooth.

  In addition, since the patent document 1 does not mention the size of the satellite, the applicant has a unique combination of the main droplet dot diameter, the satellite dot diameter, the distance from the main droplet, and the reciprocal adjustment amount in FIG. 12B described above. Is set.

  That is, the printing apparatus described in Patent Document 1 does not perform timing adjustment in consideration of the size of the satellite, so that only uniform correction can be performed. Depending on the size of the satellite, correction can be performed, and other than the satellite. Image quality degradation may occur.

  The present invention has been made to solve such a problem, and an object of the present invention is to reciprocate a recording head for ejecting ink so as to face a recording medium and to move both in the forward direction and the backward direction. Sometimes, when the ink is ejected from the recording head to form an image on the recording medium, deterioration in image quality due to the satellite is suppressed regardless of the size of the satellite.

The image forming apparatus according to the present invention includes a recording head that ejects ink, a head moving unit that reciprocates the recording head against a recording medium, and the recording head when the recording head is moving in the forward direction. The landing position on the recording medium of the main droplet discharged from the recording medium, and the landing position on the recording medium of the main droplet discharged from the recording head when the recording head is moving in the backward direction, Timing setting means for setting the ejection timing of the main droplets so as to be arranged in a direction different from the moving direction of the recording head, and a satellite size for detecting the size of the satellites discharged from the recording head along with the main droplets The forward direction and the backward direction set by the timing setting unit based on the detection unit and the size of the satellite detected by the satellite size detection unit A timing adjustment means for changing at least one of the ejection timing, which is an image forming apparatus having a.
The image forming method of the present invention is an image forming method in an image forming apparatus having a recording head for ejecting ink and a head moving means for reciprocating the recording head so as to face the recording medium. Landing position of the main droplet discharged from the recording head when moving in the forward direction on the recording medium, and main droplet discharged from the recording head when the recording head is moving in the backward direction A timing setting step of setting the ejection timing of the main droplets so that the landing positions on the recording medium are aligned in a direction different from the moving direction of the recording head, and accompanying the main droplets from the recording head The satellite size detecting step for detecting the size of the discharged satellite, and the size of the satellite based on the size of the satellite detected by the satellite size detecting step. Forward direction set by the timing setting step, an image forming method having a timing adjustment step of changing at least one of the ejection timing of the backward direction.

  According to the present invention, the recording head for ejecting ink is reciprocated so as to face the recording medium, and ink is ejected from the recording head when moving in both the forward direction and the backward direction, so that an image is printed on the recording medium. When forming, it is possible to suppress deterioration in image quality due to the satellite regardless of the size of the satellite.

FIG. 3 is a block diagram of a control unit of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram showing a means for detecting the size and position of a satellite in the image forming apparatus according to the embodiment of the present invention. 1 is a diagram illustrating a principle of detecting the size and position of a satellite in an image forming apparatus according to an embodiment of the present invention. 6 is a flowchart of a printing operation of the image forming apparatus according to the embodiment of the present invention. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing the landing position of the main droplet and the satellite by the ejection timing determination at the time of bidirectional printing in consideration of the size of the satellite. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing the landing position of the main droplet and the satellite by determining the ejection timing at the time of bidirectional printing when the satellite is small. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing the landing position of the main droplet and the satellite by determining the ejection timing during bidirectional printing when the satellite is close to the main droplet. In the image forming apparatus according to the embodiment of the present invention, it is a diagram showing the landing position of the main droplet and the satellite by determining the ejection timing at the time of bidirectional printing when the printing resolution is low. In the image forming apparatus of the embodiment of the present invention, it is a diagram showing the landing position of the main droplet and the satellite by the ejection timing determination at the time of bidirectional printing when oblique lines are printed in consideration of the size of the satellite. It is a figure which shows the positional relationship of the main droplet at the time of bidirectional | two-way printing, and a satellite. FIG. 10 is a diagram illustrating landing positions of main droplets and satellites based on ejection timing determination in bidirectional printing when a satellite is not considered in a conventional image forming apparatus. FIG. 10 is a diagram illustrating landing positions of main droplets and satellites based on ejection timing determination in bidirectional printing when the presence or absence of satellites is taken into consideration in a conventional image forming apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
<Configuration of image forming apparatus>
FIG. 1 is a block diagram of a control unit of an image forming apparatus according to an embodiment of the present invention. This image forming apparatus is an ink jet printer.

  As illustrated, an image forming apparatus according to an embodiment of the present invention includes a controller unit 1 including a CPU (Central Processing Unit) 1a, a ROM (Read Only Memory) 1b, and a RAM (Random Access Memory) 1c. A recording head drive unit 2, a movement control unit 3, a transport control unit 4, and a sensor control unit 5 connected to the controller unit 1 are provided. The recording head driving unit 2 drives the recording head 6, the movement control unit 3 controls the moving unit 7, the conveyance control unit 4 controls the conveyance unit 8, and the sensor control unit 5 controls the sensor 9.

  The recording head 6 includes a predetermined number of nozzles as recording elements arranged in a predetermined direction (for example, the sub-scanning direction), and can form an image on a recording medium by ejecting ink from the nozzles.

  The moving unit 7 includes a recording head 6 and includes a carriage as a head moving unit that reciprocates in a predetermined direction while facing the recording medium. The conveying unit 8 has a recording medium in a direction perpendicular to the carriage moving direction. Is provided with a recording medium conveying device for conveying the image. The sensor 9 includes an LD (Laser Diode) and a PD (Photo Diode). By detecting reflected light from the ink droplet (main droplet, satellite) of the laser light projected from the LD by the PD, the ink droplet The size (dot diameter) can be detected.

  Based on the printing program stored in the ROM 1b, the CPU 1a controls the recording head drive unit 2, the movement control unit 3, the conveyance control unit 4, and the sensor control unit 5 to eject ink from the recording head 6 and move the carriage. It is configured to perform (scanning) control, recording medium conveyance control, and satellite size detection.

<Detection of satellite size and position>
FIG. 2 is a diagram showing a means for detecting the size and position of the satellite in the image forming apparatus of the present embodiment, and FIG. 3 is a diagram showing the principle for detecting the size and position of the satellite. In FIG. 2, the sensor 9 may be fixed to the carriage to make the relative position with the recording head 6 constant, or may be fixed to the printer main body to change the relative position with the recording head 6.

  In FIG. 2, the movement of one satellite 110 over time is represented by 110a to 110c. The position and size of the satellite 110 are detected by applying the laser beam 50 projected from the LD 9a on the light emitting side to the satellite 110 ejected from the nozzle 6a of the recording head 6 and detecting the reflected light by the PD 9b on the light receiving side. To detect. Similarly, the position and size of the main droplet can be detected.

  In this figure, which will be described with reference to FIG. 3, satellites 110d to 110g represent the movement of one satellite 110 over time. Further, the dot diameter of the satellite 110 is R, the flying speed of the satellite 110 is v, and the width of the laser beam 50 (the length in the flying direction of the satellite 110) is h.

  First, since the reflected light starts to be detected (the moment when the lower end of the satellite 110 enters the laser beam 50, that is, immediately after the satellite 110d), the reflected light becomes stable (the moment when the entire satellite 110 enters the laser beam, that is, the satellite). Time t1 until 110e) is obtained. Next, the time t2 during which the reflected light is stable (the time during which the entire satellite 110 is in the laser beam 50, that is, the moving time from the satellites 110e to 110f) is measured.

t1, t2, R, v, and h have the relationship of the following formulas [1] and [2].
t1 = R / v Formula [1]
t2 = (h−R) / v Formula [2]

By solving equations [1] and [2] for R and v,
R = h * t1 / (t1 + t2) Formula [3]
v = h / (t1 + t2) ... Formula [4]
Thus, the dot diameter R and the flying speed v of the satellite 110 can be obtained.

  Further, the landing position on the recording surface is calculated from the flying speed v obtained here, the distance H between the recording head 6 and the recording surface of the recording medium, and the scanning speed V of the recording head 6. The same applies to the main droplet.

  Here, the detection of the satellite can be performed in advance at a portion where the idle discharge is performed in the main body, or can be confirmed during printing. In the former case, each recording head (including the meaning of each color) and satellite of each nozzle can be sequentially detected by one sensor. On the other hand, in the latter case, since ink is ejected simultaneously from each recording head (including the meaning of each color) and each nozzle, it cannot be detected by one sensor, and the maximum number of nozzle rows is multiplied by the number of nozzles in each row. A number of sensors are required.

<Printing operation of image forming device>
A printing operation of the image forming apparatus according to the present exemplary embodiment will be described with reference to a flowchart of FIG. The flow in this figure is a flow in the case where the detection of satellites is performed in advance at the location where idle discharge is performed in the main body.

  First, the controller unit 1 issues a command for ejecting ink (main droplet) from the recording head 6 to the recording head driving unit 2 and at the same time, the sensor 9 controls the size of the satellite with respect to the sensor control unit 5. An instruction to detect is issued (step S1).

  Next, based on the satellite size detected in step S1 and the information on the carriage moving speed stored in the ROM 1b, ejection during bidirectional printing is performed so that the landing position shown in FIGS. The timing (return direction ejection timing with respect to the forward direction) is calculated by the CPU 1a (step S2).

  In the next printing (step S3), the recording head 6 is driven while the moving portion (carriage) 7 is scanned. Here, when moving in the backward direction, a command to drive at the ejection timing shifted by the amount calculated in step S2 is issued to the recording head drive unit 2.

  The detection of the satellite size may be executed for each print job, or may be executed every predetermined time (for example, once a day) in consideration of the ink consumption amount and the print time. It may be executed at an arbitrary timing designated by the user.

<Landing position of main drop and satellite>
Next, the landing positions of main droplets and satellites during bidirectional printing in the image forming apparatus of this embodiment will be described with reference to FIGS. These figures show main droplets and satellites that land on the recording medium by executing step S3 of FIG.

  FIG. 5 is a diagram showing the landing positions of main droplets and satellites by determining the ejection timing during bidirectional printing when the size of the satellites is taken into consideration. In this figure, the same reference numerals as those in FIG. 12 are given to portions corresponding to those in FIG.

  5A and 5B show the same landing patterns as in FIGS. 12A and 12B, respectively. That is, in FIG. 5A, the landing position of the main droplet 101 ejected from the recording head 6 when the recording head 6 is moving in the forward direction, and from the recording head 6 when the recording head 6 is moving in the backward direction. The ejection timing of the main droplets 101 and 102 is set so that the landing position of the ejected main droplet 102 is aligned on the recording medium in a direction orthogonal to the moving direction of the recording head 6. The dot diameters of the main drops 101 and 102 are 100 μm, the dot diameters of the satellites 111 and 112 are 30 μm, and the distances from the main drops 101 and 102 to the corresponding satellites 111 and 112 are 70 μm. Further, the reciprocal adjustment amount in FIG. 5B, that is, the amount by which the discharge timing at the time of backward movement in FIG. 5A is advanced is 35 μm.

  In FIG. 5C, the dot diameters (100 μm) of the main drops 101 and 102, the dot diameters (50 μm) of the satellites 111 and 112, and the distances (70 μm) from the main drops 101 and 102 to the corresponding satellites 111 and 112 are Although it is the same as FIG. 12C, the reciprocation adjustment amount is 45 μm, which is earlier than the time corresponding to 10 μm from FIG. 12C.

  In this way, by considering the size of the satellite and optimally setting the reciprocation adjustment amount, the left and right ends of the ruled lines become smooth lines L3 and L4 (FIG. 5B) and L5 and L6 (FIG. 5C). .

  Here, in order to maximize the smoothness of the ruled line, in this embodiment, the size of the satellite is taken into consideration, and the outline of the main droplet and the satellite are arranged in a straight line (= positional relationship in which one common tangent can be drawn) The reciprocal adjustment amount is determined as follows.

  This condition is set as shown in FIG. 5A, that is, the landing position of the main droplet 101 ejected from the recording head 6 when the recording head 6 moves in the forward direction, and the recording head 6 From the state where the landing position of the main droplet 102 ejected from the recording head 6 when moving in the backward direction is set to be aligned in a direction perpendicular to the moving direction of the recording head 6 on the recording medium, Discharge timing to land at a position shifted backward (rightward) in the moving direction of the recording head 6 by “distance between droplet and satellite” + “satellite dot diameter ÷ 2” − “main dot dot diameter ÷ 2”. Adjust.

  FIG. 6 is a diagram showing the landing positions of the main droplet and the satellite by determining the ejection timing during bidirectional printing when the satellite is small. In this figure, the same reference numerals as those in FIG.

  FIG. 6A shows the same landing pattern as FIG. 5A. FIGS. 6B and 6C show the case where there are small satellites 111 and 112 corresponding to the main droplets 101 and 102 of the landing pattern of FIG. 6A (dot diameter 10 μm). In FIG. 6B, the reciprocation adjustment amount is 0, and in FIG. 6C, it is 25 μm.

  If the satellite is very small relative to the main droplet, it is difficult to see even if it is attached to the paper surface. Therefore, if adjustment is made so as to land at a position shifted by “distance between main droplet and satellite” + “satellite dot diameter ÷ 2” − “main dot dot diameter ÷ 2”, a ruled line as shown in FIG. 6C. At the left end L7 and the right end L8, the reciprocal displacement of the main droplets 101 and 102 becomes conspicuous. Rather, the reciprocal adjustment amount with the satellites 111 and 112 ignored as shown in FIG. 6B may be preferable. Therefore, when the ratio of the size of the satellite to the size of the main droplet is equal to or less than a predetermined value, the reciprocal adjustment amount considering only the main droplet is set without considering the satellite (the reciprocation adjustment amount is set to 0). It is desirable.

  Also, the size of the generated satellite is detected, and whether to set the reciprocating adjustment amount considering the satellite or whether to set the reciprocating adjustment amount considering only the main droplet without considering the satellite. The device may be configured to be selectable according to user preferences.

  FIG. 7 is a diagram illustrating the landing positions of the main droplet and the satellite by determining the ejection timing at the time of bidirectional printing when the satellite is close to the main droplet. In this figure, the same reference numerals as those in FIG.

  FIG. 7A is obtained by changing the distance from the main droplets 101 and 102 to the satellites 111 and 112 from 70 μm to 40 μm in FIG. 11C. When the recording head 6 is scanned, if the scanning speed is lowered, the satellite landing position approaches the landing position of the main droplet, so that it is difficult to visually recognize the satellite. This is known as prior art (Japanese Patent Laid-Open No. 2005-144904 / Patent No. 3888347).

  At this time, if only the size of the satellite is considered and the reciprocation adjustment amount is 45 μm as in FIG. 6C, the adjustment amount is too large as shown in FIG. 7B, and smoothness may be lost. Therefore, it is desirable to set the reciprocation adjustment amount to 15 μm as shown in FIG. 7C in consideration of not only the size of the satellite but also the distance from the main droplet to the satellite. The reciprocal adjustment amount is as described in the explanatory text of FIG.

  FIG. 8 is a diagram illustrating the landing positions of main droplets and satellites based on the ejection timing determination during bidirectional printing when the printing resolution is low. In this figure, the same reference numerals as those in FIG.

  FIG. 8A is obtained by reducing the resolution in the direction perpendicular to the scanning direction of the recording head 6 to 1/3 in FIG. 11A. When a satellite similar to that shown in FIG. 11C is generated, the result is as shown in FIG. 8B. Even in such a low resolution, the smoothness of the ruled line can be increased as shown in FIG. 8C by adding the reciprocal adjustment amount shown in the present embodiment.

  However, when the resolution is low, the dot interval is widened, and even when there are satellites 111 and 112 as shown in FIG. When the resolution is low, it may be desirable to set the reciprocal adjustment amount considering only the main drops 101 and 102 without considering the satellites 111 and 112.

  Therefore, the image forming apparatus or the user's preference whether to set the reciprocal adjustment amount considering the satellite for each resolution or setting the reciprocal adjustment amount considering only the main droplet without considering the satellite. It is good to have a configuration that can be selected by

  FIG. 9 is a diagram showing the landing positions of main droplets and satellites by determining the ejection timing during bidirectional printing when oblique lines are printed in consideration of the size of the satellites. In this figure, the same reference numerals as those in FIG.

  In FIG. 5, the dot group arranged in the direction perpendicular to the moving direction (scanning direction) of the recording head 6 is described. However, the direction in which the dot group constituting the ruled line is arranged is different from the moving direction of the recording head 6. There is no need to limit it. For example, when a ruled line at an angle of 45 ° is printed as shown in FIG. 9A, if a satellite similar to that shown in FIG. 5C is generated, the result is as shown in FIG. Also in this case, the reciprocal adjustment amount is set so that the outlines of the main droplets 101 and 102 and the satellites 111 and 112 are arranged in a straight line as shown in FIG. 9C (= a positional relationship in which one common tangent can be drawn). If it is made, a ruled line can be made smooth.

  The conditions for this are as follows: “Distance between main drop and satellite” + “Satellite dot diameter ÷ √2” − “Main drop dot diameter ÷ √2” Become.

  In general, when printing a ruled line with an angle θ that is perpendicular to the direction in which the recording head 6 is scanned, “distance between main droplet and satellite” + “satellite dot diameter ÷ 2 cos θ” − “ The position is shifted by “main droplet dot diameter ÷ 2 cos θ”. Therefore, until the angle θ reaches 90 °, the shift amount decreases as the angle θ increases (for example, 45 μm when θ = 0 ° (FIG. 5C), 34.6 μm when θ = 45 °, and θ = 60 °). Sometimes 20 μm).

  In the above embodiment, the discharge timing at the backward movement is changed, but the discharge timing at the forward movement may be changed. Further, the ejection timing in both the forward direction and the backward direction may be changed.

  DESCRIPTION OF SYMBOLS 1 ... Controller part, 2 ... Recording head drive part, 3 ... Movement control part, 4 ... Conveyance control part, 5 ... Sensor control part, 6 ... Recording head, 7 ... Movement control part, 8 ... Conveyance part, 9 ... Sensor.

Japanese Patent No. 4192629

Claims (9)

A recording head for ejecting ink;
Head moving means for reciprocating the recording head against the recording medium;
Landing position on the recording medium of the main droplets ejected from the recording head when the recording head is moving in the forward direction, and ejection from the recording head when the recording head is moving in the backward direction Timing setting means for setting the ejection timing of the main droplet so that the landing position of the main droplet on the recording medium is aligned in a direction different from the moving direction of the recording head;
Satellite size detecting means for detecting the size of the satellite discharged from the recording head accompanying the main droplet;
A timing adjusting means for changing at least one ejection timing in the forward direction and the backward direction set by the timing setting means based on the size of the satellite detected by the satellite size detecting means;
An image forming apparatus. The image forming apparatus according to claim 1,
The image forming apparatus that changes the ejection timing so that the timing adjusting unit can draw a common tangent to the main droplet and satellite landed on the recording medium. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the direction different from the moving direction of the recording head is a direction orthogonal to the moving direction of the recording head. The image forming apparatus according to claim 3.
Main drop size detecting means for detecting the size of the main drop, and distance detecting means for detecting the distance between the main drop and the satellite,
The timing adjustment means is an image forming apparatus that changes the ejection timing for a time corresponding to “distance between main droplet and satellite” + “satellite dot diameter ÷ 2” − “main dot dot diameter ÷ 2”. The image forming apparatus according to claim 1,
Having a main droplet size detection means for detecting the size of the main droplet;
The timing adjustment unit is an image forming apparatus that sets a time for changing the ejection timing to 0 when a ratio of a satellite size to a main droplet size is a predetermined value or less. The image forming apparatus according to claim 1,
Having a distance detecting means for detecting the distance between the main droplet and the satellite;
The timing adjustment unit is an image forming apparatus that determines a time for changing the ejection timing in consideration of a distance between a main droplet and a satellite. The image forming apparatus according to claim 1,
The image forming apparatus in which the timing adjustment unit sets a time for changing the ejection timing to 0 when a main droplet ejection interval in a direction perpendicular to the moving direction of the recording head is equal to or greater than a predetermined value. The image forming apparatus according to claim 1,
An image forming apparatus having means for selecting whether or not to operate the timing adjusting means according to a user operation. An image forming method in an image forming apparatus, comprising: a recording head that ejects ink; and a head moving unit that reciprocates the recording head so as to face the recording medium.
Landing position on the recording medium of the main droplets ejected from the recording head when the recording head is moving in the forward direction, and ejection from the recording head when the recording head is moving in the backward direction A timing setting step for setting the ejection timing of the main droplet so that the landing position of the main droplet on the recording medium is aligned in a direction different from the moving direction of the recording head;
A satellite size detecting step for detecting the size of the satellite discharged from the recording head along with the main droplet;
A timing adjustment step for changing at least one ejection timing in the forward direction and the backward direction set by the timing setting step based on the size of the satellite detected by the satellite size detection step;
An image forming method comprising:

Images