Image formation apparatus, density adjustment method, and program

Abstract

To provide an image formation apparatus, a density adjustment method, and a program capable of appropriately determining the amount of pretreatment agent and adjusting the density of a formed image.SOLUTION: An image formation apparatus comprises: a first ink jet head which discharges a pretreatment agent; a second ink jet head which discharges ink; and a control unit which controls discharges by the first ink jet head and the second ink jet head. The control unit forms, on a recording medium, an adjustment image containing the pretreatment agent and the ink, and having a plurality of patterns in which the amount of the pretreatment agent is varied stepwise, and determines the amount of the pretreatment agent on the basis of the density of each pattern in the adjustment image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus, a density adjustment method, and a program. [Background technology]

[0002] Inkjet image forming apparatuses (hereinafter referred to as "inkjet image forming apparatuses") have been known that eject ink onto a recording medium such as cloth or paper to form an image on the recording medium. In inkjet image forming apparatuses, the degree of ink penetration varies depending on the type of recording medium being printed on, which can result in image defects such as bleeding or white spots.

[0003] To prevent such image defects, a pretreatment agent such as a coagulant that adjusts the ink permeability is applied. However, applying a pretreatment agent changes the ink density, which can result in users not being able to obtain the image quality they desire.

[0004] Therefore, recently, it has been proposed to appropriately adjust the amount of pretreatment agent so as to obtain an image of a desired quality. For example, Patent Document 1 discloses a printing device that acquires information about the recording medium to be used, such as the material and folding method of the recording medium, in advance, and determines the amount of pretreatment agent based on this information about the recording medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-50968 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the printing device described in Patent Document 1, even if the amount of pretreatment agent used is determined based on the information about the recording medium, there is a risk that image defects may actually occur due to factors that contribute to permeability other than the information contained in the information about the recording medium, which may result in the user not being able to obtain the quality of the image they desire.

[0007] An object of the present disclosure is to provide an image forming apparatus, a density adjustment method, and a program that are capable of appropriately determining the amount of pretreatment agent and adjusting the density of a formed image. [Means for solving the problem]

[0008] An image forming apparatus according to the present disclosure includes: a first inkjet head that ejects a pretreatment agent; a second inkjet head that ejects ink; a control unit that controls ejection by the first inkjet head and the second inkjet head; Equipped with The control unit forming an adjustment image on a recording medium, the adjustment image including the pretreatment agent and the ink, the adjustment image having a plurality of patterns in which the amount of the pretreatment agent is changed in stages; The amount of the pretreatment agent is determined based on the density of each pattern in the adjustment image.

[0009] The concentration adjustment method according to the present disclosure includes: forming an adjustment image on a recording medium, the adjustment image including a pretreatment agent and ink, the adjustment image having a plurality of patterns in which the amount of the pretreatment agent is changed in stages; The amount of the pretreatment agent is determined based on the density of each pattern in the adjustment image.

[0010] The program according to the present disclosure is The density adjustment method is executed by a computer. [Effects of the Invention]

[0011] According to the present disclosure, the amount of pretreatment agent can be appropriately determined and the density of the formed image can be adjusted. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an inkjet image forming apparatus according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of the configuration of the ink head unit 24. As shown in FIG. [Figure 3] FIG. 3 is a block diagram showing the main functional configuration of the image forming apparatus 1. As shown in FIG. [Figure 4] FIG. 4 is a schematic diagram showing a first example of an adjustment image used in the density adjustment process. [Figure 5] FIG. 5 is a schematic diagram showing a second example of an adjustment image used in the density adjustment process. [Figure 6] FIG. 6 is a schematic diagram showing a third example of an adjustment image used in the density adjustment process. [Figure 7] FIG. 7 is a schematic diagram showing an example of an area where an adjustment image is formed. [Figure 8] FIG. 8 is a schematic diagram showing another example of the region where the adjustment image is formed. [Figure 9] FIG. 9 is a flowchart showing an example of the flow of the density adjustment process according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments, and various modifications are possible without departing from the spirit of the present disclosure. In addition, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

[0014] [Configuration of inkjet image forming apparatus 1] The present embodiment will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing an example of the configuration of an inkjet image forming apparatus 1 according to the present embodiment. As shown in Fig. 1, the inkjet image forming apparatus (hereinafter simply referred to as "image forming apparatus") 1 includes a supply section 10, an image forming section 20, a discharge section 30, and a control section 40 (see Fig. 3).

[0015] Under the control of the control unit 40, the image forming apparatus 1 transports the recording medium P stored in the supply unit 10 to the image forming unit 20. Then, the image forming apparatus 1 forms an image on the recording medium P in the image forming unit 20, and transports the recording medium P with the image formed to the discharge unit 30. For example, a fabric is used as the recording medium P. However, the recording medium P is not limited to this, and various media capable of fixing ink that has landed on its surface, such as paper such as plain paper or coated paper, as well as sheet-like resin, can be used.

[0016] The supply unit 10 has a storage unit 11 that stores the recording medium P, and a medium supply unit 12 that transports and supplies the recording medium P from the storage unit 11 to the image forming unit 20. The medium supply unit 12 has a ring-shaped belt supported on the inside by two rollers, and transports the recording medium P from the storage unit 11 to the image forming unit 20 by rotating the rollers with the recording medium P placed on this belt.

[0017] The image forming section 20 includes a transport section 21, a delivery unit 22, a heating section 23, an ink head unit 24, a pretreatment agent head unit 26, a drying section 25, a delivery section 28, and the like.

[0018] The transport unit 21 holds the recording medium P placed on a transport surface 211a (mounting surface) of a cylindrical transport drum 211. The transport unit 21 also performs a transport operation of transporting the recording medium P on the transport drum 211 in the transport direction (Y direction) by rotating and moving the transport drum 211 around a rotation axis (cylindrical axis) extending in the X direction (the direction perpendicular to the paper surface of FIG. 1).

[0019] The transport drum 211 has claws and an air intake section (not shown) for holding the recording medium P on its transport surface 211a. The recording medium P is held on the transport surface 211a by having its edges pressed down by the claws and being drawn to the transport surface 211a by the air intake section. The transport section 21 is connected to a transport drum motor (not shown) for rotating the transport drum 211. The transport drum 211 rotates by an angle proportional to the amount of rotation of the transport drum motor.

[0020] The transfer unit 22 transfers the recording medium P transported by the medium supply unit 12 of the supply unit 10 to the transport unit 21. The transfer unit 22 is disposed at a position between the medium supply unit 12 of the supply unit 10 and the transport unit 21. The transfer unit 22 holds and picks up one end of the recording medium P transported from the medium supply unit 12 with a swing arm unit 221, and transfers it to the transport unit 21 via a transfer drum 222.

[0021] The heating section 23 is disposed between the position where the delivery drum 222 is disposed and the position where the ink head unit 24 is disposed. The heating section 23 heats the recording medium P conveyed by the conveyance section 21 so that the temperature of the recording medium P falls within a predetermined temperature range. The heating section 23 has, for example, an infrared heater or the like, and energizes the infrared heater based on a control signal supplied from the control section 40 (see FIG. 3 ) to cause the infrared heater to generate heat.

[0022] The ink head unit 24 forms an image by ejecting ink onto the recording medium P held on the transport drum 211. Specifically, the ink head unit 24 ejects ink onto the recording medium P from ink ejection ports formed on a nozzle surface 245 (see FIG. 2) facing the transport surface 211a of the transport drum 211 at appropriate timing according to the rotation of the transport drum 211. The ink head unit 24 is disposed so that the ink ejection ports and the transport surface 211a are spaced apart by a predetermined distance.

[0023] In the image forming apparatus 1 of the present embodiment, four ink head units 24 are arranged corresponding to four colors of ink, yellow (Y), magenta (M), cyan (C), and black (K). Specifically, for example, the four ink head units 24 are arranged at predetermined intervals in the order of Y, M, C, and K from the upstream side in the conveyance direction of the recording medium P.

[0024] 2 is a schematic diagram showing an example of the configuration of the ink head unit 24. Here, the nozzle surface of the ink head unit 24 that faces the transport surface 211a of the transport drum 211 is shown.

[0025] The ink head unit 24 includes four inkjet heads 242 attached to a mounting member 244. Each inkjet head 242 is formed with a plurality of image forming elements (recording elements), each having a pressure chamber that stores ink, a piezoelectric element arranged on the wall of the pressure chamber, and a nozzle 243. When a drive signal that causes the piezoelectric element to deform is input, the image forming element deforms the pressure chamber due to the deformation of the piezoelectric element, changing the pressure inside the pressure chamber, and ejecting ink from the nozzle 243 that communicates with the pressure chamber.

[0026] In the inkjet head 242, two nozzle rows each consisting of nozzles 243 arranged at equal intervals in a direction intersecting the transport direction of the recording medium P (in this embodiment, a direction perpendicular to the transport direction, i.e., the X direction) are formed on the nozzle surface 245. These two nozzle rows are arranged such that the positions of the nozzles 243 are shifted from each other in the X direction by half the arrangement interval of the nozzles 243 in each nozzle row.

[0027] The four inkjet heads 242 are arranged in a staggered pattern so that the arrangement range of the nozzle rows in the X direction is continuous without any breaks. The arrangement range in the X direction of the nozzles 243 included in the ink head unit 24 covers the width in the X direction of the area on the recording medium P transported by the transport unit 21 where an image is formed. At this time, the position of the ink head unit 24 is fixed with respect to the rotation axis of the transport drum 211 during image formation. In other words, the ink head unit 24 has a line head that can eject ink across the image formable width in the X direction on the recording medium P, and the image forming apparatus 1 is a single-pass image forming apparatus.

[0028] The number of nozzle rows in the inkjet head 242 may be one or three or more, instead of two. The number of inkjet heads 242 in the head unit 24 may be three or less, or five or more, instead of four. The inkjet head 242 corresponds to the "second inkjet head" of the present disclosure.

[0029] 1 , the pretreatment agent head unit 26 ejects a pretreatment agent onto the recording medium P held on the transport drum 211, thereby pretreating the recording medium P. Specifically, the pretreatment agent head unit 26 ejects the pretreatment agent onto the recording medium P from pretreatment agent ejection ports formed in a nozzle face (not shown) that faces the transport surface 211 a of the transport drum 211, at appropriate timing according to the rotation of the transport drum 211.

[0030] The pretreatment agent head unit 26 is disposed upstream in the transport direction from the ink head unit 24. More specifically, the pretreatment agent head unit 26 is disposed between the position of the heating section 23 and the position of the ink head unit 24. The pretreatment agent head unit 26 is also disposed such that the pretreatment agent ejection openings and the transport surface 211a are separated by a predetermined distance.

[0031] 2, and includes an inkjet head 262, a nozzle 263, an attachment member 264, and a nozzle surface 265. The inkjet head 262 corresponds to the "first inkjet head" of the present disclosure.

[0032] In this embodiment, for example, a flocculant is used as the pretreatment agent. The flocculant is used to adjust the permeability of the ink. By mixing the flocculant with the ink, the ink flocculates, and bleeding and other problems on the recording medium P are suppressed.

[0033] The density measurement unit 27 measures the density of the image formed on the recording medium P. The density measurement unit 27 is configured to include, for example, a light irradiation unit and a light receiving sensor, and detects light irradiated from the light irradiation unit and reflected from the image with the light receiving sensor. The density measurement unit 27 then measures the density of the image based on the amount of received light that has been detected. The density measurement unit 27 supplies the measurement result to the control unit 40.

[0034] The drying section 25 has a heat source such as a heater and an air blower such as a fan, and dries the ink on the recording medium P by blowing hot air onto the image forming surface (upper surface) of the recording medium P placed on the conveying section 21. The drying section 25 is disposed opposite the conveying surface 211a in the conveying direction between the position where the ink head unit 24 is disposed and the position where the delivery drum 281 of the delivery section 28 is disposed.

[0035] In this example, the drying unit 25 is described as being integrally formed inside the image forming unit 20, but this is not limiting, and the drying unit 25 may be configured as a separate unit from the image forming unit 20. When the drying unit 25 is configured as a separate unit from the image forming unit, the drying unit 25 is disposed, for example, between the image forming unit 20 and the discharge unit 30.

[0036] The delivery unit 28 has a cylindrical delivery drum 281 that delivers the recording medium P from the conveyance unit 21 to the belt loop 282, and the belt loop 282 has a ring-shaped belt supported on the inside by two rollers. The delivery unit 28 transports the recording medium P delivered onto the belt loop 282 from the conveyance unit 21 by the delivery drum 281, using the belt loop 282, and sends it to the discharge unit 30.

[0037] The discharge section 30 has a placement section 31 on which the recording medium P sent out from the image forming section 20 by the delivery section 28 is placed.

[0038] Fig. 3 is a block diagram showing the main functional configuration of image forming apparatus 1. As shown in Fig. 3, image forming apparatus 1 includes heating unit 23, head drive unit 241 and inkjet head 242, head drive unit 261 and inkjet head 262, drying unit 25, control unit 40, transport drive unit 51, operation display unit 52, and input / output interface 53.

[0039] The head driver 241 supplies a drive signal to the image forming elements of the inkjet head 242 at appropriate timing to deform the piezoelectric elements in accordance with image data. As a result, the head driving unit 241 causes the nozzles 243 of the inkjet head 242 to eject ink in an amount corresponding to the pixel value of the image data.

[0040] The head driving unit 261 supplies driving signals to the image forming elements of the inkjet head 262 at appropriate timing to deform the piezoelectric elements in accordance with the image data. As a result, the head driving unit 261 ejects a predetermined amount of pretreatment agent from the nozzles 263 of the inkjet head 262.

[0041] The control unit 40 controls the entire image forming apparatus 1. In particular, in the present embodiment, the control unit 40 controls the head drive unit 241 of the ink head unit 24 and the head drive unit 261 of the pretreatment agent head unit 26. This performs a concentration adjustment process that adjusts the ink concentration. The concentration adjustment process will be described in detail later.

[0042] The control unit 40 includes a CPU 41 (Central Processing Unit), a RAM 42 (Random Access Memory), a ROM 43 (Read Only Memory), and a storage unit 44.

[0043] The CPU 41 reads out various control programs and setting data stored in the ROM 43, stores them in the RAM 42, and executes the programs to perform various arithmetic processing. The CPU 41 also performs overall control of the overall operation of the image forming apparatus 1.

[0044] The RAM 42 provides a working memory space for the CPU 41 and stores temporary data. The RAM 42 may include a non-volatile memory.

[0045] The ROM 43 stores various control programs and setting data executed by the CPU 41. Note that the ROM 43 may be replaced by a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory.

[0046] The storage unit 44 stores print jobs (image formation commands) input from the external device 2 via the input / output interface 53, image data related to the print jobs, and the like. The print job includes information specifying the image data related to the image to be formed, as well as information related to the type of recording medium P on which the image is to be formed (for example, the type, size, thickness, etc. of the recording medium P). The storage unit 44 may be, for example, an HDD (Hard Disk Drive), or may also be used in combination with a DRAM (Dynamic Random Access Memory).

[0047] Furthermore, storage unit 44 stores various types of information required for control unit 40 to control each unit. For example, in the present embodiment, storage unit 44 stores information indicating the relationship between the conditions related to recording medium P, such as the type and thickness of recording medium P, and the amount and concentration of pretreatment agent, when performing a density adjustment process, which will be described later. This information is used when performing density adjustment processes when the conditions, such as the type and thickness of recording medium P, are the same.

[0048] The transport drive unit 51 supplies a drive signal to the transport drum motor of the transport drum 211 based on a control signal supplied from the control unit 40, thereby rotating the transport drum 211 at a predetermined speed and timing.

[0049] Furthermore, the conveyance driving unit 51 supplies drive signals to motors for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 28 based on control signals supplied from the control unit 40. This causes the conveyance driving unit 51 to supply the recording medium P to the conveyance unit 21 and discharge the recording medium P from the conveyance unit 21.

[0050] The operation display unit 52 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as operation keys or a touch panel overlaid on the screen of the display device. The operation display unit 52 displays various information on the display device, and converts user input operations on the input device into operation signals and outputs them to the control unit 40.

[0051] The input / output interface 53 mediates the transmission and reception of data between the external device 2 and the control unit 40. The input / output interface 53 is configured, for example, by any one of various serial interfaces, various parallel interfaces, or a combination of these.

[0052] The external device 2 is, for example, a personal computer, and supplies print jobs, image data, and the like to the control unit 40 via an input / output interface 53 .

[0053] [Ink Density Adjustment] 4 is a schematic diagram showing a first example of an adjustment image used in the density adjustment process. Here, an example will be described in which a coagulant is used as a pretreatment agent and density is adjusted using ink of one of the colors Y, M, C, or K.

[0054] In the density adjustment process, first, an adjustment image is formed on the recording medium P, as shown in Fig. 4. The adjustment image is an image formed in order to adjust the density of the image when an actual image is formed.

[0055] The adjustment image is, for example, a test pattern in which a plurality of flocculant patterns are printed with the amount of flocculant varied stepwise within a predetermined range, and ink of the same concentration is printed on the flocculant patterns. In other words, the adjustment image is an image including a plurality of patterns with different amounts of flocculant. In this example, the adjustment image is formed so that the amount of flocculant increases stepwise in the direction opposite to the conveyance direction.

[0056] In the adjustment image thus formed, each pattern contained in the adjustment image is a mixture of aggregating agent and ink. Since the ink concentration is the same in one adjustment image, the concentration of each pattern contained in the adjustment image varies depending on the amount of aggregating agent.

[0057] Therefore, the density of each pattern included in the adjustment image is measured, and the amount of flocculant to be used is determined by selecting a pattern with the density desired by the user from the measurement results.The determined amount of flocculant is then set in the image forming apparatus 1, thereby adjusting the density when an actual image is formed.

[0058] In this way, by using an adjustment image in which the amount of coagulant is changed in stages, the amount of pretreatment agent required to achieve the desired density can be appropriately determined, and the density of the formed image can be adjusted.

[0059] When performing density adjustment processing, if the conditions such as the type and thickness of the recording medium P are the same as those when density adjustment processing was previously performed, the density adjustment processing may be omitted by using the information stored in the storage unit 44. This reduces the time required for image formation and improves productivity.

[0060] In addition, in this example, the ink density of the adjustment image is kept the same and the density of the formed image is adjusted, but this is not limited to this, and in addition to gradually changing the amount of coagulant, the ink density may also be gradually changed to adjust the density of the formed image.

[0061] Fig. 5 is a schematic diagram showing a second example of an adjustment image used in the density adjustment process. In this case, as shown in Fig. 5, in the density adjustment process, a plurality of adjustment images are formed on the recording medium P, including a first adjustment image using ink of a predetermined density and a second adjustment image using ink of a different density. In this example, the adjustment images are formed side by side in the transport direction of the recording medium P so that the ink density increases in the direction opposite to the transport direction.

[0062] In the plurality of adjustment images thus formed, the density of each pattern differs depending on the ink density and the amount of aggregating agent. Therefore, the density of each pattern included in the adjustment image is measured, and the amount of aggregating agent to be used is determined by selecting a pattern with the density desired by the user from the measurement results. The determined amount of aggregating agent is then set in the image forming apparatus 1, thereby adjusting the density when an actual image is formed.

[0063] In this way, by optimizing both the ink concentration and the amount of aggregating agent, the actual image concentration can be set with higher precision.

[0064] Furthermore, in this example, the amount of aggregating agent is determined using ink of a single color, but the present invention is not limited to this, and the amount of aggregating agent corresponding to each of a plurality of colors may be determined.

[0065] Fig. 6 is a schematic diagram showing a third example of an adjustment image used in the density adjustment process. In this case, in the density adjustment process, as shown in Fig. 6, a plurality of adjustment images using inks of different colors are formed on the recording medium P. In this example, the adjustment images are formed lined up in the conveyance direction of the recording medium P so that the ink colors are Y, M, C, and K in that order from the left side in the conveyance direction.

[0066] In the plurality of adjustment images thus formed, the density of the pattern for each color differs depending on the ink density and the amount of aggregating agent. Therefore, the density of each pattern included in the adjustment image is measured, and a pattern with the density desired by the user for each color is selected from the measurement results, thereby determining the amount of aggregating agent to be used. The determined amount of aggregating agent is then set in the image forming apparatus 1, thereby adjusting the density when an actual image is formed.

[0067] In this way, by optimizing the aggregating agent for each ink color, it is possible to appropriately set the concentration for each ink color.

[0068] (Determining the amount of flocculant) The amount of aggregating agent required to aggregate ink varies depending on the ink's solids concentration, and the higher the solids concentration of the pigments and other components in the ink, the greater the amount of aggregating agent required to aggregate the ink. This solids concentration varies depending on the color of the ink.

[0069] Therefore, when determining the amount of aggregating agent, it is preferable to determine the amount of aggregating agent according to the ink with the highest solid content concentration. Therefore, when determining the amount of aggregating agent, it is preferable to form an adjustment image using the ink of the color with the highest solid content concentration, and then perform the density adjustment process.

[0070] In this way, by determining the amount of coagulant for the color of ink that requires the most coagulant, it is possible to reduce the time required to adjust the inks of other colors and the amount of ink required when performing concentration adjustment processing.

[0071] Furthermore, the amount of aggregating agent required to aggregate the ink varies greatly depending on the type and thickness of the recording medium P. Therefore, the range of the amount of aggregating agent that is gradually changed when forming the adjustment image may be changed depending on the type and thickness of the recording medium P. This improves the accuracy in determining the amount of aggregating agent.

[0072] In particular, when the recording medium P is fabric, the appropriate amount of flocculant varies widely depending on the type of fabric, fabric thickness, folding method, etc., compared to when the recording medium P is paper. Therefore, the amount of flocculant when forming the adjusting image is, for example, 10 to 40 g / m 2 This is because if the amount of the aggregating agent is too large, the ink will be excessively aggregated, and if the amount of the aggregating agent is too small, the ink aggregation effect will not be obtained.

[0073] The aggregating agent is used to aggregate the ink used in image formation, so the amount of aggregating agent should be adjusted after determining the concentration of the ink to be used.

[0074] At this time, if the recording medium P on which the image is actually formed is fabric, the ink concentration is determined using paper as the recording medium P. The amount of coagulant, which is greatly affected by the type and thickness of the recording medium P, should be determined using the fabric that is actually used.

[0075] (Regarding the timing of density adjustment processing) As described above, the optimum amount of aggregating agent varies greatly depending on the type and thickness of the recording medium P. Therefore, it is preferable that the density adjustment process be performed using the recording medium P on which an actual image will be printed. Therefore, it is preferable that the density adjustment process be performed, for example, when the recording medium P is replaced with one that will be used when actually printing an image, and before the image is formed.

[0076] Furthermore, the density adjustment process may be performed when the image forming apparatus 1 is started up so as not to affect the subsequent productivity.

[0077] Furthermore, when the operating environment of the image forming apparatus 1, such as temperature and humidity, changes, the optimal amount of flocculant for the desired density of the formed image may change even when the same type and thickness of image forming apparatus 1 is used. Therefore, when determining the optimal amount of flocculant, a density adjustment process may be performed in accordance with changes in the operating environment.

[0078] In this case, for example, a temperature and humidity sensor is provided in the image forming apparatus 1, and the concentration adjustment process is performed when the temperature and humidity detected by the temperature and humidity sensor change. This reduces errors in the amount of flocculant due to changes in the environment in which the image forming apparatus 1 is used, and makes it possible to more reliably obtain the desired concentration.

[0079] (Regarding the adjustment image formation area) The adjustment image is formed, for example, in a non-image forming area of ​​the recording medium P excluding the image forming area where an actual image is formed.

[0080] Fig. 7 is a schematic diagram showing an example of an area where an adjustment image is formed. Fig. 8 is a schematic diagram showing another example of an area where an adjustment image is formed. In the example shown in Fig. 7, the adjustment image is formed, for example, at the edge of the recording medium P.

[0081] 8, the adjustment image is formed, for example, between multiple jobs that form images on the recording medium P. That is, the adjustment image is formed, for example, in a non-image forming area between an image forming area for an image formed by a first job and an image forming area for an image formed by a second job.

[0082] [Density adjustment processing] 9 is a flowchart showing an example of the flow of density adjustment processing according to the present embodiment. In this example, a case will be described in which a coagulant is used as a pretreatment agent and density is adjusted using ink of one of the colors Y, M, C, or K.

[0083] In step S1, the control unit 40 forms an adjustment image on the recording medium P. Specifically, first, the control unit 40 causes a flocculant, which is a pretreatment agent, to be ejected onto the recording medium P to form a flocculant pattern.

[0084] The aggregating agent pattern is formed, for example, by ejecting the aggregating agent from the nozzles 263 of the pretreatment agent head unit 26 while transporting the recording medium P. At this time, the control unit 40 controls the head driving unit 261 of the pretreatment agent head unit 26 so that the amount of the ejected aggregating agent changes at a predetermined timing.

[0085] Next, the control unit 40 ejects ink onto the aggregant patterns from the nozzles 243 of the ink head unit 24 while transporting the recording medium P. As a result, an adjustment image having a different density for each pattern is formed on the recording medium P.

[0086] In step S2, the control unit 40 measures the density of each pattern of the adjustment image based on the amount of light irradiated from the light irradiating unit of the density measuring unit 27 and reflected by the adjustment image.

[0087] In step S3, the control unit 40 determines the amount of flocculant desired by the user based on the measured concentration for each pattern. For example, the control unit 40 digitizes the concentration for each pattern based on the measurement results, and selects a concentration pattern that corresponds to a value included in a predetermined range from the concentrations of each pattern.

[0088] Then, in step S4, the control unit 40 sets the amount of coagulant of the selected pattern as the optimal amount of coagulant when using the current recording medium P. The amount of coagulant set in this way becomes the optimal amount of coagulant when forming an image of the quality desired by the user.

[0089] As described above, the image forming apparatus 1 according to the present embodiment forms an adjustment image having a plurality of patterns in which the amount of coagulant is changed in stages on the recording medium P, and determines the amount of coagulant based on the density of each pattern in the adjustment image. In this way, the amount of coagulant is determined according to the recording medium P, so that the density of the image that is actually formed can be set appropriately.

[0090] In this embodiment, the amount of flocculant is determined using the recording medium P on which an actual image is formed. Therefore, even if the recording medium P to be used is an unknown recording medium P for which the amount of flocculant required is unknown, the amount of flocculant can be optimized.

[0091] Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present disclosure. For example, in the present embodiment, the image forming apparatus 1 is of a single-pass type, but the present disclosure is not limited to this, and the image forming apparatus 1 may be of a scan type, for example.

[0092] When the image forming apparatus 1 is a scanning type, the amount of flocculant can be changed stepwise in one scan, thereby reducing the time required to form the adjustment image, and therefore reducing the time required for one density adjustment process. [Explanation of symbols]

[0093] 1. Inkjet image forming device 2 External device 10 Supply section 20 Image forming unit 24 Ink head unit 26 Pre-treatment head unit 27 Concentration measurement section 30 Discharge section 40 Control Unit 241, 261 Head drive unit 242, 262 inkjet head 243, 263 nozzles 245, 265 nozzle surface

Claims

1. a first inkjet head that ejects a pretreatment agent; a second inkjet head that ejects ink; a control unit that controls ejection from the first inkjet head and the second inkjet head; Equipped with The control unit forming an adjustment image on a recording medium, the adjustment image including the pretreatment agent and the ink, the adjustment image having a plurality of patterns in which the amount of the pretreatment agent is changed in stages; determining the amount of the pretreatment agent based on the density of each pattern in the adjustment image; Image forming device.

2. The control unit forming the adjustment image on the recording medium by adding the pretreatment agent to the ink and changing the density of the ink; The image forming apparatus according to claim 1 .

3. The control unit forming the adjustment image for each of the ink colors on the recording medium; determining the amount of the pretreatment agent for each color of the ink; The image forming apparatus according to claim 1 .

4. The control unit forming the adjustment image using the ink of the color having the highest solid content concentration among the inks; The image forming apparatus according to claim 1 .

5. The control unit determining a range of the amount of the pretreatment agent to be changed in stages depending on the type and thickness of the recording medium; The image forming apparatus according to claim 1 .

6. The amount of the pretreatment agent is 10 to 40 g / m ２ That is, The image forming apparatus according to claim 5 .

7. The control unit forming the adjustment image after determining the amount of ink to be used when forming the adjustment image; The image forming apparatus according to claim 1 .

8. The control unit When the recording medium is a fabric, the ink concentration is determined using paper, and the amount of the pretreatment agent is determined using the recording medium. The image forming apparatus according to claim 7 .

9. The control unit When the recording medium is replaced, the adjustment image is formed before an actual image is formed. The image forming apparatus according to claim 1 .

10. The control unit forming the adjustment image at startup; The image forming apparatus according to claim 1 .

11. a temperature and humidity sensor for detecting the temperature and humidity inside the device; The control unit forming the adjustment image based on the detection result by the temperature and humidity sensor; The image forming apparatus according to claim 1 .

12. The control unit forming the adjustment image in a non-image forming area of ​​the recording medium excluding an image forming area where an actual image is to be formed; The image forming apparatus according to claim 1 .

13. the non-image forming area is an edge of the recording medium; The image forming apparatus according to claim 12.

14. the non-image forming area is between each of the images formed by the plurality of jobs; The image forming apparatus according to claim 12.

15. a light irradiation unit that irradiates the adjustment image with light; a light receiving sensor that detects light reflected from the adjustment image; and a density measurement unit that measures the density of each pattern in the adjustment image based on the amount of reflected light received, The image forming apparatus according to claim 1 .

16. a storage unit that stores information indicating a relationship between the conditions related to the recording medium and the amount and concentration of the pretreatment agent, The image forming apparatus according to claim 1 .

17. forming an adjustment image on a recording medium, the adjustment image including a pretreatment agent and ink, the adjustment image having a plurality of patterns in which the amount of the pretreatment agent is changed in stages; determining the amount of the pretreatment agent based on the density of each pattern in the adjustment image; How to adjust concentration.

18. A program that causes a computer to execute the density adjustment method according to claim 17.

Images