JP2024006202A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device which suppresses voids of a solid image for various printing media, and can secure fine character reproducibility.

SOLUTION: An image formation device includes: a head part 10 which has a plurality of nozzles for discharging droplets to a printing medium arranged in a predetermined direction, and discharges the droplets to the printing medium while moving relative to the printing medium; a head condition determination part 41 for determining at least one head condition of angles in the arrangement direction of the plurality of nozzles of the head part 10 in a direction perpendicular to the relative moving direction, and a partial used nozzle selected from the plurality of nozzles, on the basis of the diameters of dots printed on the predetermined printing medium by the head part 10; and a head control part 42 for controlling discharge of the droplets from the nozzles of the head part 10, on the basis of at least the one head condition.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an image forming apparatus that performs printing using a head section in which a plurality of nozzles are arranged.

2. Description of the Related Art Conventionally, inkjet printing apparatuses have been proposed that perform printing processing by ejecting ink from an inkjet head onto a print medium.

In general, in the case of industrial inkjet printing apparatuses, there are a wide variety of types of printing media, and it has been proposed to perform printing processing on, for example, film.

Japanese Patent Application Publication No. 2011-5806

However, for example, if the printing medium is a base material coated with an ink-receiving layer, ink bleeding will be small, and if printing is performed with a small ejection amount, there is a risk that the solid image will not be filled and white spots will occur. be.

On the other hand, when the printing medium is a non-permeable base material such as film or glass, or a permeable base material without an ink-receiving layer such as cardboard, the ink bleeds significantly. If the base material has large ink bleeds, barcodes such as QR codes (registered trademarks) and one-dimensional barcodes, and details of characters may be destroyed.

Therefore, a method may be considered in which the dot diameter is adjusted depending on the type of printing medium (bleeding rate), for example. A possible method for adjusting the dot diameter is to adjust the amount of ink ejected per dot.

However, when using a multi-drop type inkjet head, although the ejection amount can be changed by the number of drops, the waveform length of the drive waveform of the inkjet head becomes long. The waveform length is the length of the waveform supplied to eject an ink drop required to form one dot, and if it is long, the ejection frequency will be slow, resulting in a decrease in productivity.

On the other hand, when using a binary inkjet head capable of high-speed ejection, the number of gradations is two, so the amount of ink ejected is, in principle, constant. Changes in the ejection amount due to adjustments to the drive voltage and waveform of the inkjet head are minute, and furthermore, the volume is proportional to the cube of the radius, so no significant change in droplet diameter can be expected.

Furthermore, since the driving conditions of the inkjet head are usually set in consideration of ink flying speed, satellites, etc., it is difficult to change only the ejection amount independently.

Note that Patent Document 1 proposes a method of adjusting the landing position by adjusting the angle of the inkjet head according to changes in the expansion and contraction of the printing medium, but the angle takes into account the bleeding as described above. Since it is not an adjustment, it cannot solve the above problem.

In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus that can suppress white spots in solid images and ensure fine print reproducibility for various print media.

The image forming apparatus of the present invention includes a head section in which a plurality of nozzles that eject droplets onto a print medium are arranged in a predetermined direction, and a dot diameter based on the diameter of a dot when printing on a predetermined print medium by the head section. the angle of the arrangement direction of the plurality of nozzles of the head section with respect to the direction perpendicular to the direction of relative movement between the print medium and the head section, and at least one of some of the nozzles to be used selected from the plurality of nozzles; The apparatus includes a head condition determination section that determines one head condition, and a control section that controls ejection of droplets from a nozzle of the head section based on at least one head condition.

According to the image forming apparatus of the present invention, based on the diameter of the dots printed on a predetermined print medium by the head unit, the angle of the arrangement direction of the plurality of nozzles of the head unit with respect to the direction perpendicular to the relative movement direction and The head condition of at least one of the selected nozzles to be used is determined, and the ejection of droplets from the nozzle of the head section is controlled based on the determined head condition. The dot pitch can be optimized, white spots in solid images can be suppressed, and fine print reproducibility can be ensured for various printing media.

A block diagram showing a schematic configuration of an inkjet printing device using an embodiment of an image forming device of the present invention Diagram showing the schematic configuration of the head section Flowchart for explaining the printing process of the inkjet printing device shown in FIG. 1 Diagram showing the relationship between dot diameter and dot pitch Diagram showing an example of adjusting the angle of the head part Diagram showing other examples of head angle adjustment Diagram for explaining control of discharge timing of each nozzle in the head section

EMBODIMENT OF THE INVENTION Hereinafter, an inkjet printing apparatus 1 using an embodiment of an image forming apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an inkjet printing apparatus 1 of this embodiment.

The inkjet printing device 1 performs printing processing by ejecting ink droplets onto a sheet-like print medium such as paper or film based on image data output from a computer or image data output from a document reading device. .

As shown in FIG. 1, the inkjet printing apparatus 1 includes a head section 10, a conveyance section 20, a reading section 30, a control section 40, and an adjustment mechanism 50.

FIG. 2 is a diagram showing a schematic configuration of the head section 10 of this embodiment. As shown in FIG. 2, the head unit 10 of this embodiment has a plurality of nozzles 10a arranged in a direction perpendicular to the printing medium conveyance direction. In the present embodiment, hereinafter, the direction perpendicular to the conveyance direction of the print medium M may be referred to as the main scanning direction, and the conveyance direction of the print medium may be referred to as the sub-scanning direction.

By ejecting ink from each nozzle 10a of the head unit 10, a straight line extending in the main scanning direction is printed. The head unit 10 forms an image on the print medium by sequentially ejecting ink and repeatedly printing in a straight line extending in the main scan direction as the print medium is transported in the sub-scan direction.

The transport unit 20 includes a transport mechanism that transports the print medium. The conveyance mechanism includes, for example, an annular belt and a belt platen roller, and is configured by passing the annular belt between belt platen rollers arranged to sandwich the head unit 10 in the conveyance direction of the print medium. Under the control of the control section 40, the belt platen roller is rotated to move the annular belt, thereby conveying the print medium attracted onto the annular belt toward the head section 10.

The print medium is conveyed directly below the head section 10, and ink is ejected from each nozzle 10a of the head section 10 at a predetermined ejection timing, so that printing is performed sequentially on the conveyed print medium. be exposed.

The reading unit 30 photoelectrically reads a document image to be printed to obtain image data. Further, the reading unit 30 photoelectrically reads the print medium on which the dot pattern for dot measurement is printed by the head unit 10 to obtain dot data.

The dot pattern is a pattern of dots formed by each nozzle 10a of the head unit 10, and is a pattern in which dots corresponding to each nozzle 10a are regularly arranged in the main scanning direction and the sub-scanning direction. The dot pattern is printed in a state before the angle adjustment of the head unit 10 described later, that is, in a state in which the arrangement direction of the nozzles 10a of the head unit 10 is the same as the main scanning direction.

The image data and dot data read by the reading section 30 are output to the control section 40.

The control unit 40 includes a CPU, a semiconductor memory, and the like, and controls the entire inkjet printing apparatus 1 . The control unit 40 controls the operation of each part of the inkjet printing apparatus 1 by executing a control program stored in advance in a storage medium such as a semiconductor memory or a hard disk and operating an electric circuit.

Specifically, the control section 40 includes a head condition determination section 41, a head control section 42, and a transport control section 43.

Here, the control unit 40 of this embodiment performs printing according to the degree of bleeding on the printing medium. The head condition determination unit 41 receives the dot data acquired by the reading unit 30, and determines the angle of the head unit 10 and the nozzles to be used in the head unit 10 based on the received dot data.

The angle of the head section 10 is the angle of the arrangement direction of the plurality of nozzles 10a of the head section 10 with respect to the main scanning direction. The used nozzles of the head section 10 are the nozzles used for actual ejection among the plurality of nozzles 10a included in the head section 10, and are, for example, some of the nozzles 10a after thinning out the plurality of nozzles 10a at a predetermined nozzle interval. A nozzle is selected. In addition, there are cases in which the nozzles 10a are not thinned out, only the angle of the head portion 10 is adjusted, and all the nozzles 10a are used.

The method of determining the angle of the head section 10 and the nozzles to be used in the head condition determination section 41 will be described in detail later.

The head control section 42 receives image data output from the computer or the reading section 30, and performs various processes on the image data. Then, the head control section 42 outputs a control signal to the head section 10 based on the processed image data, and controls ink ejection from each nozzle 10a of the head section 10.

Further, the head control unit 42 forms a print image on the print medium according to the image data by controlling the timing of ink ejection from each nozzle 10a of the head unit 10.

Further, the head control section 42 adjusts the angle of the head section 10 by controlling an adjustment mechanism 50, which will be described later, based on the angle of the head section 10 determined by the head condition determining section 41. Further, the head control section 42 controls the head section 10 based on the used nozzles determined by the head condition determination section 41, and performs printing by ejecting ink only from the used nozzles. That is, the head control unit 42 performs printing by ejecting ink from only some of the nozzles in use by thinning out the plurality of nozzles 10a included in the head unit 10. However, as described above, the head control section 42 may only adjust the angle of the head section 10 and may not thin out the nozzles 10a.

The conveyance control section 43 controls the conveyance speed of the print medium by the conveyance section 20 .

The adjustment mechanism 50 is a mechanism that adjusts the angle of the head section 10. In this embodiment, a rotation shaft is provided at one end of the head section 10, and the head section 10 is configured to be rotatable by moving the other end of the head section 10 about the rotation shaft. The adjustment mechanism 50 includes a cam member that contacts the head portion 10 and a motor that rotates the cam member, as described in, for example, Japanese Patent Application Publication No. 2010-228434. Adjust the angle of section 10. However, the configuration of the adjustment mechanism 50 is not limited to this, and any mechanism that can adjust the angle of the head portion 10 may be employed.

Next, the printing process of the inkjet printing apparatus 1 of this embodiment will be described with reference to the flowchart shown in FIG. 3. Here, the method for determining the angle of the head section 10 and the nozzle to be used in the head condition determining section 41 will be mainly explained.

First, as a prerequisite, the angle of the head unit 10 is assumed to be based on the assumption that a film base material is used as the printing medium, and a product name and a QR code (registered trademark) are to be reprinted on a part of the film base material with a printing width of about 30 mm. and how to decide which nozzle to use. The configuration of the head unit 10 is such that the nozzle resolution N is 400 dpi, the ink ejection amount Q from each nozzle 10a is 30 pL (droplet diameter d is 38.6 μm), the maximum print width Lmax is 60 mm, and the ejection frequency is Let f be 35kHz. The maximum printing width is the maximum width that can be printed by the head section 10 before angle adjustment. Further, the ejection frequency is a frequency calculated from the reciprocal of the ejection cycle of ink forming one line.

First, the head condition determination unit 41 acquires information on the nozzle resolution, droplet diameter, and maximum print width of the head unit 10 (S10). The initial information of the head unit 10 is stored in a computer (for example, a computer that outputs image data) (not shown) connected to the inkjet printing device 1, an operation panel (not shown) provided in the inkjet printing device 1, etc. Set. The droplet diameter refers to the diameter of the droplet after it is ejected from the nozzle 10a but before it lands on the print medium, and is a known value that is set based on the ink used and the driving conditions of the head.

Then, the head condition determining unit 41 calculates parameters such as the dot pitch P, the minimum dot diameter Dmin, the maximum dot diameter Dmax, and the allowable angle range θmax of the head unit 10 based on the initial information of the head unit 10 (S12 ).

FIG. 4 is a diagram showing the relationship between dot diameter and dot pitch. The dot pitch P is the interval between dots printed by the head unit 10 when the angle of the head unit 10 is 0° (the direction in which the nozzles 10a are arranged and the main scanning direction are the same). Therefore, the dot pitch P can be calculated from the nozzle resolution, and in this embodiment, P=25.4 mm/400 dpi=63.5 μm.

Further, the minimum dot diameter Dmin is √2×P=89.8 μm, and the maximum dot diameter Dmax is 2×P=127 μm. Note that when Dmin<√2×P, the solid image is not filled with dots and white spots occur. Furthermore, if Dmax>2×P, the dots will overlap and the white line will be crushed.

Further, the allowable range θmax of the angle of the head unit 10 is θmax=cos ⁻¹ (L/Lmax)=cos ⁻¹ (30 mm/60 mm)=60°, assuming that the effective printing width L is 30 mm. The effective print width L is the print width that can be printed after the angle of the head unit 10 is adjusted. By determining the permissible range θmax of the angle of the head unit 10 based on the effective printing width L in this way, it is possible to avoid a problem in which the angle of the head unit 10 is too large and the printing width becomes insufficient. be able to.

Next, the head condition determination unit 41 measures the diameter of the dot printed by the head unit 10 (S14). Specifically, the reading section 30 reads a dot pattern for dot measurement, and the head condition determining section 41 acquires dot data.

Then, the head condition determination unit 41 calculates the average dot diameter Dave, the dot diameter variation α, and the average bleeding rate Kn of the printing medium based on the input dot data (S16). The average bleeding rate Kn of the print medium is defined as Dave/d based on the average dot diameter Dave and the droplet diameter d. For example, the standard deviation σ can be used as the variation α, but in order to reliably prevent white spots in a solid image, it is preferable to use about 3σ.

Then, the head condition determining unit 41 compares the dot diameter D _±α , which takes into account the variation α with respect to the average dot diameter Dave, with the minimum dot diameter Dmin and the maximum dot diameter Dmax.

First, if the variation α is ±3%, the head condition determination unit 41 compares the minimum dot diameter Dmin with the dot diameter D _{- α} , which takes into account the variation -3% with respect to the average dot diameter Dave (S18). . If D _{- α} ≦Dmin (S18, NO), the solid image will not be filled, and the process proceeds to a process for determining head conditions (angle of the head unit 10 and nozzles to be used), which will be described later.

On the other hand, if D _{- α} > Dmin (S18, YES), the head condition determining unit 41 compares the dot diameter D _{+ α} considering the variation +3% with respect to the average dot diameter Dave and the maximum dot diameter Dmax. (S20). Then, if D _{+ α} ≧Dmax (S20, NO), the head condition determining unit 41 determines the head condition (head unit 10 Proceed to the process of determining the angle and nozzle used).

Here, for the sake of explanation, a specific example will be given and explained. For example, if the average bleeding rate Kn of the first printing medium is 2 (actually a value calculated from the measured value), the average dot diameter Dave of the first printing medium is Dave=d×Kn=38 .6 μm×2=77.2 μm. When the dot diameter variation α is α=±3%, the dot diameter D _−α =74.8 μm considering the variation of −3%, which is smaller than Dmin, so that the solid image will not be filled.

On the other hand, for example, if the average bleeding rate Kn of the second printing medium is 3 (actually a value calculated from the measured value), then the average dot diameter Dave of the second printing medium is Dave=d×Kn= 38.6 μm×3=115.8 μm. When the dot diameter variation α is set to α=±3%, the dot diameter D _{+ α=} 120 μm≈Dmax considering the variation +3%, and the amount of ink applied becomes excessive and the white line is considerably crushed.

Note that although Dmax is not exceeded for the second print medium, since the amount of ink applied is large, there is a high possibility that details such as the QR code (registered trademark) will be destroyed.

Therefore, in the present embodiment, the head condition determination unit 41 determines that even if D _{+ α} <Dmax (S20, YES), if the fine print priority mode is set (S22, YES), the head condition determination unit 41 determines that The process proceeds to determination of head conditions (angle of the head section 10 and nozzles used). The fine print priority mode is a mode that gives priority to clearly printing fine print, and is set and input by the user in advance.

Then, in S20, if D _{+ α} <Dmax and the fine print priority mode is not set (S22, NO), the head condition determining unit 41 does not change the angle of the head unit 10, and does not change the angle of the head unit 10. Printing is performed at the normal head resolution without thinning out the 10 nozzles 10a (S24).

Next, the above-mentioned head condition determination process will be explained below.

First, the head condition determining unit 41 calculates the effective resolution Ne that provides the optimum dot pitch P' based on the following formula (S26). Δα is the amount of variation in dot diameter, and is the value obtained by multiplying the above-mentioned variation α (for example, 3%) by the average dot diameter Dave.
Effective resolution Ne=25.4/(((d×Kn)−Δα)/√2)

Here, the optimum dot diameter D of the dots printed by the head unit 10 is within the range of D>√2×P=Dmin and D<2×P=Dmax, where P is the dot pitch calculated from the nozzle resolution N. It is. From the viewpoint of fine line reproducibility, the optimum dot diameter D=√2×P+Δα.

Therefore, the optimal dot pitch P' at which the average dot diameter Dave measured from the dot data becomes the optimal dot diameter D is P' = (Dave - Δα)/√2, and the resolution at which this optimal dot pitch P' Defining as the effective resolution Ne, the above equation can be derived. Note that in this embodiment, the effective resolution Ne is calculated using the average blur rate Kn, but the effective resolution Ne may also be calculated by calculating the above-mentioned optimal dot pitch P'.

The effective resolution Ne is an optimal resolution that can reliably fill a solid image even if variations in dot diameter are taken into account, and that prevents details from being lost.

The control unit 40 performs resolution conversion processing on the input image data so that it can be printed at the above-mentioned effective resolution Ne (S28). A known method can be used for the resolution conversion process.

Then, the head condition determination unit 41 calculates the head angle θ, which is the angle of the head unit 10, and the thinning rate 1/n of the nozzles 10a of the head unit 10, based on the effective resolution Ne and the nozzle resolution N (S30).

Specifically, when the effective resolution Ne≧nozzle resolution N, the head condition determining unit 41 calculates the head angle θ based on the following formula.
Head angle θ=cos ^-1 (N/Ne)

Note that when the head angle θ is within the range of 0°<θ<θmax (=60°), the head condition determining unit 41 determines the calculated head angle θ as the angle of the head unit 10. . On the other hand, if the head angle θ calculated based on the above equation is larger than 60°, the print width is less than the effective print width, and the user may not be able to perform desired printing. Therefore, processing such as temporarily stopping printing and displaying a message asking the user whether or not to continue printing is performed.

In addition, in the case of effective resolution Ne<nozzle resolution N, the head condition determination unit 41 sets n of the thinning rate 1/n to 2 or more and, based on the following formula, within the range of 0°<θ<θmax, A combination of the angle at which the head angle θ becomes the smallest and the thinning rate 1/n is calculated.
Head angle θ=cos ^-1 (N/Ne×1/n)

Note that when the thinning rate is 1/n, the nozzles 10a of the head section 10 are thinned out to 1/n, and the nozzles to be used are determined. For example, when the thinning rate is 1/2, the nozzles 10a of the head section 10 are thinned out to 1/2, and every other nozzle is determined to be used. When the thinning rate is 1/3, the nozzles 10a of the head section 10 are thinned out to 1/3, and every second nozzle is determined to be used.

Then, the head control unit 42 controls the adjustment mechanism 50 based on the above-mentioned head angle θ to adjust the angle of the head unit 10 (S32). Further, the head control unit 42 assigns the nozzles to be used determined based on the thinning rate of 1/n as described above as ink ejection nozzles (S32). Thereby, the dot pitch can be optimized, white spots in solid images can be suppressed, and fine print reproducibility can be ensured for various printing media.

Furthermore, in this embodiment, the effective resolution is calculated as described above, and the angle of the head unit 10 is determined based on the effective resolution, so that it is possible to calculate an appropriate head angle by simple calculation processing. can.

Furthermore, since variations in dot diameter are taken into account when calculating the effective resolution, a more appropriate head angle can be calculated. That is, by taking into account the variation in dot diameter, it is possible to calculate a head angle that can more reliably suppress white spots in a solid image and ensure fine print reproducibility.

Furthermore, in this embodiment, the angle of the head section 10 is automatically adjusted by the adjustment mechanism 50, so that the effort of manually adjusting the angle of the head section 10 can be omitted, and the angle can be adjusted with high precision. is possible.

Here, a specific example will be given and explained. In the case of the first printing medium with the above-described average bleeding rate Kn=2, when the dot diameter variation α is 3%, the effective resolution Ne=480.3 dpi according to the above calculation. Since the head angle θ=33.6°, the angle of the head portion 10 is adjusted as shown in FIG. Note that the thinning rate is 1, that is, all the nozzles 10a are used nozzles.

On the other hand, in the case of the second printing medium with the above-mentioned average bleeding rate Kn=3, when the dot diameter variation α is 3%, the effective resolution Ne=320.2 dpi according to the above calculation. Since the head angle θ=51.3°, the angle of the head portion 10 is adjusted as shown in FIG. Note that the thinning rate is 1/2. In FIG. 6, used nozzles are represented by black circles, and unused nozzles are represented by white circles.

Next, the conveyance control unit 43 sets the conveyance speed so that printing is performed at a dot pitch corresponding to the above-mentioned effective resolution Ne also in the sub-scanning direction (S34). Note that the dot pitch in the sub-scanning direction can be adjusted by changing the ejection frequency f of the head unit 10 or the conveyance speed of the print medium. In this embodiment, the dot pitch is adjusted by controlling the transport speed and the ejection timing of each nozzle 10a of the head section 10 without changing the driving conditions of the head section 10.

The adjusted conveyance speed v' is obtained by calculating v'=35kHz×25.4mm×Ne.

Further, the head control unit 42 takes the head angle θ into consideration and sets a delay time for delaying the ejection timing of each nozzle 10a (S36). The delay time Δt is calculated from the following formula.
Δt=P×n×sinθ/v'

If the nozzles used in the head unit 10 are numbered #1, #2, #3...#i in order from the earliest discharge timing (see the figure), the delay time of each nozzle is Δt× (i-1) (i is a positive integer).

Then, the print medium is conveyed at a conveyance speed v′ by the control of the conveyance unit 20 by the conveyance control unit 43, and the ejection timing from each nozzle 10a of the head unit 10 by the head control unit 42 is determined based on the delay time Δt. By controlling, printing is performed at the effective resolution Ne (S38).

Here, a specific example will be given and explained. In the case of the second printing medium described above, if the ejection timing from the nozzles used in the head unit 10 is the same, each dot is printed as shown in FIG. 7A, but the ejection timing is changed based on the delay time Δt described above. By delaying , it is possible to print with the same printing resolution in the main scanning direction and the sub-scanning direction, as shown in FIG. 7B.

Note that if the print resolution in the sub-scanning direction is different from the main scanning direction, the effective resolution Ne' in the sub-scanning direction, which is different from the above-mentioned effective resolution Ne in the main scanning direction, is set based on the diameter of the dot in the sub-scanning direction. calculate. Here, in the description of the above embodiment, the dot diameters in the main scanning direction and the sub-scanning direction are the same, but if the dot diameters in the main scanning direction and the sub-scanning direction are different (for example, the dots are elliptical) In the above embodiment, the effective resolution Ne is calculated based on the dot diameter in the main scanning direction, and the effective resolution Ne' is calculated based on the dot diameter in the sub-scanning direction as described above. . When the dot diameters in the main scanning direction and the sub-scanning direction are the same, the dot diameter in either the main scanning direction or the sub-scanning direction may be used for the effective resolution Ne'.

Then, the conveyance speed and ejection timing may be adjusted so that printing is performed at the effective resolution Ne' in the sub-scanning direction. Specifically, using the effective resolution Ne' in the sub-scanning direction, the conveyance speed v'' and Δt' are determined in the same manner as above, and the print medium is conveyed at the conveyance speed v'', and each nozzle 10a Printing may be performed at the effective resolution Ne' in the sub-scanning direction by controlling the ejection timing from 2 to 3 based on the delay time Δt'. Thereby, the dot pitch can also be optimized in the sub-scanning direction.

Furthermore, in the above embodiment, the adjustment of the angle of one head unit and the nozzle used has been described, but in the case of an inkjet printing apparatus equipped with multiple head units, similar adjustments are made for each head unit. Just do it like this.

Further, in the above embodiment, the angle of the head portion 10 is automatically adjusted using the adjustment mechanism 50, but the angle is not limited to this, and may be adjusted manually.

In addition, in the above embodiment, when measuring the dot diameter of a dot pattern, it is automatically measured from dot data, but the dot diameter is not limited to this and can be measured manually using a printed dot pattern. However, the measured value may be set and input. Alternatively, the inkjet printing device may not include a reading unit, and the inkjet printing device may acquire dot data read by a reading device provided separately from the inkjet printing device, and automatically measure the dot diameter.

It should be noted that the present invention is not limited to the above-described embodiments, and can be embodied by modifying the constituent elements within the scope of the invention at the implementation stage. Moreover, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, all the components shown in the embodiments may be combined as appropriate. It goes without saying that various modifications and applications can be made without departing from the spirit of the invention.

Regarding the present invention, the following additional notes are further disclosed.
(Additional note)

In the image forming apparatus of the present invention, the head condition determining section can calculate the effective resolution based on the diameter of the dot, and determine the head condition based on the effective resolution.

In the image forming apparatus of the present invention, the head condition determining section can calculate the effective resolution by taking into account variations in the diameter of dots printed on the print medium.

In the image forming apparatus of the present invention, the head condition determining section can determine the angle of the head section based on a print width that is preset in a direction orthogonal to the relative movement direction.

In the image forming apparatus of the present invention, the control section calculates the effective resolution in the relative movement direction based on the diameter of the dot in the relative movement direction, and calculates the effective resolution for each of the head sections based on the effective resolution. The timing of ejecting droplets from the nozzle can be controlled.

The image forming apparatus of the present invention can include an adjustment mechanism that adjusts the installation angle of the head section based on the angle of the nozzle arrangement direction determined by the head condition determining section.

1 Inkjet printing device 10 Head section 10a Nozzle 20 Conveyance section 30 Reading section 40 Control section 41 Head condition determination section 42 Head control section 43 Conveyance control section 50 Adjustment mechanism

Claims (6)

a head unit in which a plurality of nozzles are arranged in a predetermined direction for ejecting droplets onto a print medium;
The plurality of nozzles of the head unit in a direction perpendicular to the relative movement direction between the print medium and the head unit based on the diameter of a dot when printing on a predetermined print medium by the head unit. a head condition determining unit that determines the angle of the arrangement direction of the head and the head condition of at least one of some of the nozzles to be used selected from the plurality of nozzles;
an image forming apparatus comprising: a control section that controls ejection of droplets from nozzles of the head section based on the at least one head condition; The image forming apparatus according to claim 1, wherein the head condition determining section calculates an effective resolution based on the diameter of the dot, and determines the at least one head condition based on the effective resolution. The image forming apparatus according to claim 2, wherein the head condition determining section calculates the effective resolution by taking into account variations in diameters of dots printed on the print medium. The image forming apparatus according to claim 1, wherein the head condition determining section determines the angle of the head section based on a print width that is preset in a direction perpendicular to the relative movement direction. The control unit calculates an effective resolution in the relative movement direction based on the diameter of the dot in the relative movement direction, and calculates liquid from each nozzle of the head unit based on the effective resolution. The image forming apparatus according to claim 2, wherein the image forming apparatus controls the ejection timing of the droplets. The image forming apparatus according to claim 1, further comprising an adjustment mechanism that adjusts the installation angle of the head section based on the angle in the arrangement direction of the nozzles determined by the head condition determination section.