Image forming apparatus

Abstract

The present application provides an image forming apparatus capable of preventing or inhibiting unevenness of a pinning state by performing setting of a fixing condition based on an objective reference. The image forming apparatus includes: an image forming section that discharges ink of one or more colors to a recording medium to form an image; a fixing section that has a predetermined fixing section that irradiates an energy ray to the formed image to semi-cure the image, and fixes the image on the recording medium; and a setting section that sets an irradiation condition of the fixing section based on a result of a test print performed in the past when a print job is executed.

Description

Technical Field

[0001] This invention relates to an image forming apparatus. Background Technology

[0002] In recent years, inkjet image forming devices (hereinafter referred to as inkjet image forming devices) based on inkjet printing, which ejects ink from an inkjet head to print text on the recording medium, have become widely used as devices for recording ultra-fine images on various recording media such as paper and cloth.

[0003] Conventionally, in inkjet image forming apparatuses, there are known techniques for irradiating ink ejected from the inkjet head onto the recording medium with energy rays, thereby drying the ink (fixing it onto the recording medium). For example, when using UV-irradiated ink, UV light is irradiated onto the ink ejected onto the recording medium, thereby curing the ink and fixing it onto the recording medium.

[0004] Furthermore, in order to improve image quality, in single-pass inkjet image forming apparatuses for color printing, there is a known technique of irradiating UV light immediately after the ink of each color is discharged (falls) onto the recording medium to pin (semi-cur) the ink of that color.

[0005] For example, the technology described in Patent Document 1 describes adjusting the ink discharge rate and UV irradiation rate for each type of recording medium, and adjusting the diameter and thickness of the ink dots.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-182062

[0007] However, when using the technique described in Patent Document 1 to perform the above-mentioned pinning (semi-curing) process, it is not possible to fully ensure the quality of the image, for example, there are problems such as streaks in high-concentration areas or bleeding into the image.

[0008] The reason for the above problems is believed to be that the physical properties of the ink or the physical properties of the contact surface that the ink comes into contact with on the recording medium vary depending on the color of the ink or the type of recording medium used.

[0009] Specifically, in an inkjet image forming apparatus that performs color printing using multiple colors of ink, the light energy absorption characteristics differ for each color (pigment or colorant) of the ink used.

[0010] Therefore, when multiple colors of ink are applied to the same recording medium for color printing, even if the pinning conditions (UV irradiation output relative to the unit output of ink and irradiation time, etc.) are the same for each color, there is a problem of uneven pinning (semi-cured) state for each color (e.g., each ink product).

[0011] The aforementioned problem arising from uneven pinning (semi-cured) states also occurs when the same ink is ejected onto different types of recording media. That is, this is because the physical properties of the contact surface where the ink is ejected onto the recording medium differ depending on the recording medium used.

[0012] There is no solution in the prior art for the uneven pinning of each of the above colors. Whenever a new type of recording medium or ink is processed, it is necessary to print samples and study (experiment) and set pinning conditions.

[0013] However, such operations are tedious and time-consuming, and the longer the operation is delayed, the more it hinders printing productivity. In addition, if sample conditions are set based on the judgment of each operator, it is possible that the image quality will vary depending on each operator (e.g., based on their skill level). Summary of the Invention

[0014] The object of the present invention is to provide an image forming apparatus that can prevent or suppress uneven pinning of each color by setting fixing conditions based on objective benchmarks.

[0015] The image forming apparatus of the present invention comprises:

[0016] The image forming unit ejects ink of one or more colors into the recording medium to form an image;

[0017] The fixing unit includes a pre-fixing section that illuminates the formed image with energy lines to semi-solidify the image, and fixes the image onto the recording medium; and

[0018] The setting unit sets the irradiation conditions of the fixing unit in the printing task based on the printing results of previously performed test prints when executing a printing task.

[0019] According to the present invention, unevenness in the pinning state can be prevented or suppressed by setting fixing conditions based on objective benchmarks. Attached Figure Description

[0020] Figure 1 This is a side view showing a simplified structure of the image forming apparatus in this embodiment.

[0021] Figure 2 It means Figure 1 A block diagram of the main functional structure of the image forming apparatus.

[0022] Figure 3A as well as Figure 3B This table shows examples of image quality changes when the amount of UV irradiation and the ink curing time are changed during the pinning process.

[0023] Figure 4 This is a diagram representing a specific example of a gradient image printed during test printing.

[0024] Figure 5 It is a table representing a specific instance of a concentration threshold input by the user. Detailed Implementation

[0025] Hereinafter, the inkjet image forming apparatus of this embodiment will be described in detail with reference to the accompanying drawings. Figure 1 This is a side view showing a simplified structure of the image forming apparatus 1 according to this embodiment. Additionally, Figure 2 This is a block diagram showing the main functional structure of the image forming apparatus 1.

[0026] like Figure 1 As shown, the image forming apparatus 1 includes: a transport unit 2 that transports the recording medium P along the transport path in the transport direction; multiple head units 10 (in this example, five colors W, K, C, M, and Y are used) that serve as an image forming unit for forming an ink image (hereinafter referred to as "image") on the recording medium P by inkjet printing; and a first UV irradiation unit 25 and a second UV irradiation unit 28, which will be described later.

[0027] The conveying unit 2 includes: a feed roller 21 disposed at the uppermost end of the conveying path, a driven roller 22 disposed downstream of the feed roller 21 and upstream of the head unit 10, a driven roller 24 disposed downstream of the second UV irradiation unit 28, and a winding roller 23 disposed at the lowermost end of the conveying path.

[0028] exist Figure 1 In the structural example shown, the recording medium P is configured to use a long strip of medium such as cloth or roll paper, which is pre-wound onto the feed roller 21 and then wound by the winding roller 23 via the driven rollers 22 and 24.

[0029] The rotational drive of the feed roller 21 and the winding roller 23 is achieved through Figure 2 Under the control of the control unit 40 (described later), the drive force of the first drive motor and the second drive motor (not shown) of the transmission drive unit 51 is transmitted to perform the operation.

[0030] Furthermore, the structure of the conveying unit 2 is not limited to this; for example, it can also be a rotating structure such as an ink transfer roller, a conveying roller, or a conveyor belt used to convey cut papers one sheet at a time.

[0031] The head unit 10 discharges ink from the ink discharge surface opposite to the recording medium P via the transport unit 2, thereby forming an image on the recording medium P.

[0032] exist Figure 1In one specific example shown, five head units 10, each corresponding to a different color of ink (white (W), black (K), cyan (C), magenta (M), and yellow (Y), are arranged sequentially at predetermined intervals, starting from the upstream side along the transport direction of the recording medium P.

[0033] Each head unit 10 is equipped with an inkjet head 102 (see reference). Figure 2 The inkjet head 102 is provided with multiple recording elements, each of which has a pressure chamber for storing ink, a piezoelectric element disposed on the wall of the pressure chamber, and a nozzle. When a drive signal is input to the recording element to deform the piezoelectric element, the pressure chamber deforms due to the deformation of the piezoelectric element, the pressure inside the pressure chamber changes, and ink is discharged from the nozzle connected to the pressure chamber.

[0034] The nozzles included in the inkjet head 102 are in contact with Figure 1 The configuration range in the vertical direction (hereinafter referred to as "orthogonal direction") of the attached figure covers the width of the orthogonal direction of the area in the recording medium P in which the image is formed by the transport unit 2.

[0035] The head unit 10 is used in a fixed position relative to the rotation axis of the feed roller 21 or the winding roller 23 during image formation. That is, the image forming apparatus 1 is a single-pass inkjet image forming apparatus.

[0036] In this example, the ink discharged from the inkjet head 102 to the recording medium P is a UV-curable ink whose viscosity varies depending on the energy supplied to the recording medium P (in this example, the amount of ultraviolet light supplied from the first UV irradiation unit 25 and the second UV irradiation unit 28, described later).

[0037] In addition, as a recording medium P, besides ordinary paper, coated paper, etc., various media such as cloth or sheet resin, which can fix the ink that falls on the surface, can also be used.

[0038] Next, the main references are... Figure 2 The other main functional structures in the image forming apparatus 1 will be described below. The image forming apparatus 1 includes: a head drive unit 101 and an inkjet head 102 in the head unit 10, a first UV irradiation unit 25 and a second UV irradiation unit 28, an operation display unit 34, a control unit 40, a transport drive unit 51, an input / output interface 52, etc.

[0039] Based on the control of the control unit 40, the head drive unit 101 outputs a drive signal to the recording element of the inkjet head 102 at appropriate timing according to the image data, causing the piezoelectric element to deform, thereby discharging an amount of ink from the nozzle of the inkjet head 102 corresponding to the pixel value of the image data.

[0040] The control unit 40 includes a CPU 41 (Central Processing Unit), RAM 42 (Random Access Memory), ROM 43 (Read Only Memory), and a storage unit 44.

[0041] CPU 41 reads various control programs and setting data stored in ROM 43 and stores them in RAM 42, then executes the programs to perform various calculations. In addition, CPU 41 controls the overall operation of image forming apparatus 1.

[0042] RAM42 provides memory space for CPU41 to perform operations and temporarily store data. In addition, RAM42 may also contain non-volatile memory.

[0043] ROM43 stores various control programs and setting data executed by CPU41. Alternatively, ROM43 can be replaced by rewritable non-volatile memory such as EEPROM (Electrically Erasable Programmable Read Only Memory) or flash memory.

[0044] The storage unit 44 stores print jobs (including image formation instructions containing various user-defined information such as the number of pages to print) input from the external device 200 via the input / output interface 52, as well as image data related to the print job. The storage unit 44 may be, for example, an HDD (Hard Disk Drive), or alternatively, DRAM (Dynamic Random Access Memory).

[0045] The conveying drive unit 51 supplies drive signals to the first drive motor, the second drive motor, etc., based on the control signal supplied from the control unit 40, so that the feed roller 21 and the winding roller 23 rotate at a predetermined speed and time.

[0046] The input / output interface 52 serves as a medium for transmitting and receiving data between the external device 200 and the control unit 40. The input / output interface 52 may be composed of, for example, any one of various serial interfaces, various parallel interfaces, or a combination thereof.

[0047] The external device 200, such as a personal computer (PC), supplies printing tasks and image data to the control unit 40 via the input / output interface 52.

[0048] The first UV irradiation unit 25 performs the following function: under the control of the control unit 40, it irradiates the recording medium P, which has formed an image (i.e., ink falling) through the inkjet head 102 of the image forming unit, i.e., the head unit 10, with UV light (ultraviolet light), thereby partially curing (semi-curing or pre-curing) the (image) on the recording medium P and pre-shaping it. This pre-shaping process is sometimes referred to as "pinning".

[0049] Specifically, such as Figure 1 as well as Figure 2 As shown, the first UV irradiation unit 25 has four first UV irradiation units 25w, 25k, 25c and 25m arranged near the downstream side of the head unit 10 corresponding to the four colors of ink: white (W), black (K), cyan (C) and magenta (M), starting from the upstream side along the transport direction of the recording medium P.

[0050] In this embodiment, the first UV irradiation unit 25 (25w, 25k, 25c and 25m) corresponds to the "predetermined irradiation unit" of the present invention.

[0051] Furthermore, the first UV irradiation section 25 (25y) is not provided near the downstream side of the head unit 10 corresponding to the yellow (Y) ink. The reason for this is that the yellow (Y) image is the most downstream, so no pre-curing process is required, and the formal curing process can be performed only once in the second UV irradiation section 28.

[0052] The second UV irradiation unit 28 performs the following function: under the control of the control unit 40, it irradiates the recording medium P, which has passed through the head unit 10 that discharges yellow (Y) ink, with UV light (ultraviolet light), thereby completely curing (formally curing) the (image) on the recording medium P and completing the fixing of the recording medium P.

[0053] Thus, in this embodiment, the first UV irradiation unit 25 (25w, 25k, 25c and 25m) and the second UV irradiation unit 28 correspond to the "fixing unit" of the present invention.

[0054] The operation display unit 34, for example, is a liquid crystal display (LCD) with a touch panel, serving as both a display unit and an operation unit. Based on display control signals input from the control unit 40, the display unit shows various operation screens, image status, and the operational status of each function. The operation unit has various operation keys such as numeric keys and a start key, accepts various user-based input operations, and outputs operation signals to the control unit 40.

[0055] In this embodiment, the operation display unit 34 and the control unit 40, especially the control unit 40, have the function of a "setting unit" in this invention, and the details of the setting unit will be described later.

[0056] Next, a brief description of the operation of the image forming apparatus 1 when performing a printing task will be provided. When a printing task is received from the external device (PC) 200 via the input / output interface 52, the image forming apparatus 1 performs the following operations under the control of the control unit 40.

[0057] First, the control unit 40 controls the transport drive unit 51 of the transport unit 2 to start the transport of the recording medium P, so that the paper feeding and transporting operation of the recording medium P can be started.

[0058] Next, the control unit 40 controls the ejection of ink from the inkjet head 102 of the corresponding color from the print head unit 10. Through the above actions, an image of the color and shape specified by the printing task is formed on the recording medium P.

[0059] Furthermore, the control unit 40 controls the first UV irradiation unit 25 and the second UV irradiation unit 28 to irradiate the recording medium P on which the image has been formed with UV light for pinning and formal curing, and performs the pinning (pre-image) and formal curing process of the image on the recording medium P.

[0060] The recording medium P, after the aforementioned pinning and curing processes, is wound onto the winding roller 23 via the driven roller 24. Furthermore, once the required amount of image formation specified in the printing task has been achieved, the aforementioned series of processes concludes.

[0061] However, in the inkjet image forming apparatus 1 that uses multiple colors of ink for color printing as described above, the light energy absorption characteristics are different for each color (colorant) of the ink used, which sometimes results in image quality degradation, such as streaks in high-concentration areas or bleeding in the image.

[0062] Specifically, in the image forming apparatus 1 that uses multiple colors of ink for color printing, the light energy absorption characteristics differ for each color (colorant) of the ink used. Furthermore, actual ink products also contain various substances (which can be considered impurities) other than colorants, such as drying inhibitors used to prevent nozzle clogging.

[0063] Therefore, when multiple colors of ink are applied to the same recording medium P for color printing, even if the pinning conditions (UV irradiation output relative to the unit output of ink and irradiation time, etc.) in the first UV irradiation section 25 (25w to 25m) are the same for each color, there is a problem that the pinning (semi-cured) state is uneven for each color (e.g., each ink product).

[0064] The aforementioned problem arising from uneven pinning (semi-cured) states also occurs when the same ink is ejected onto different types of recording media P. That is, this is because the physical properties of the contact surface where the ink is ejected onto the recording media P differ depending on the recording media P used.

[0065] There is no solution in the prior art for the uneven pinning of each of the above colors. Whenever a new type of recording medium or ink is processed, it is necessary to print samples and study (experiment) and set pinning conditions.

[0066] exist Figure 3A as well as Figure 3B The table below provides an overview of pinning condition settings related to ink properties. Figure 3A This is a table showing general settings for pinning conditions (intensity of UV irradiation) when adjusting the wetting and diffusion method of the ink.

[0067] like Figure 3A As shown in the table, generally speaking, the stronger (more) the UV irradiation light output from the first UV irradiation unit 25 (25w~25m), the smaller the wetting and diffusion pattern of the ink in the pinning process. Conversely, the weaker (less) the output UV irradiation light, the greater the wetting and diffusion pattern of the ink in the pinning process.

[0068] on the other hand, Figure 3B This is a table showing general settings for pinning conditions (time until pre-curing) when adjusting the gloss and detail reproducibility of the ink.

[0069] like Figure 3B As shown in the table, generally speaking, to reduce the gloss of the ink, the amount of UV light output from the first UV irradiation unit 25 (25w to 25m) is increased to speed up the curing time of the ink. In this case, the ink's detail reproduction is also better.

[0070] Conversely, to enhance the gloss of the ink, the amount of UV light emitted from the first UV irradiation unit 25 (25w to 25m) is reduced to slow down the ink's curing time. On the other hand, with this setting, the ink's detail reproduction is worse compared to a faster curing time.

[0071] In general, whenever the user (operator) of the image forming apparatus 1 deals with a new type of recording medium P or ink, he studies the pinning conditions of the first UV irradiation unit 25 (25w to 25m), and in order to obtain an image of the desired quality, he attempts to repeatedly print samples and change settings, and then decides on the final settings to be used in the actual printing.

[0072] However, such operations are tedious and time-consuming, and the longer the operation is delayed, the more it hinders printing productivity. In addition, if the stapling conditions in the actual printing are set based on the judgment of each operator, it is possible that the image quality will vary from operator to operator (e.g., based on skill level).

[0073] The inventors have devoted themselves to research in order to solve the above-mentioned problems, and as a result, the image forming apparatus 1 is provided with the following structure or function.

[0074] That is, the image forming apparatus 1 of this embodiment is configured to include a setting unit, which sets (selects or changes) the irradiation conditions (output, time, etc.) in the fixing unit (first UV irradiation unit 25 (25w to 25m) and second UV irradiation unit 28) based on the printing results of previously performed test prints when performing a printing task.

[0075] In a specific example Figure 2 The operation display unit 34 and the control unit 40 in the middle function as the aforementioned "setting unit".

[0076] Specifically, the control unit 40 performs the processing for performing the "test printing" described above. In addition, the control unit 40 performs processing to ensure that the printing results of the test printing are mainly reflected in the pinning irradiation conditions (output, time, etc.) in the first UV irradiation unit 25 (25w to 25m).

[0077] In one specific example, the control unit 40 sets the irradiation energy of the UV light irradiated by the first UV irradiation unit 25 (25w to 25m) during the execution of a printing task to the irradiation condition of the fixing unit.

[0078] Furthermore, the irradiation conditions for the fixing unit include the presence or absence of UV light irradiation in each of the first UV irradiation units 25w, 25k, 25c, and 25m, as well as the setting of the irradiation energy. For example, when printing an image that does not expel white (W) ink during a printing task (in actual printing), the control unit 40 sets the first UV irradiation unit 25w to not irradiate with UV light (setting the irradiation energy to zero).

[0079] Thus, the control unit 40 sets the irradiation energy of the UV light irradiated by the corresponding first UV irradiation unit 25 (25w to 25m) according to each type of ink discharged from the head unit (image forming unit) 10.

[0080] On the other hand, the operation display unit 34 performs the following function: displaying a setting screen or input screen for various settings (selection or change) for the user to perform test printing or print jobs (i.e., formal printing), thereby providing convenience for the user.

[0081] In addition, the operation display unit 34 displays a database (accumulated or updated data) related to the irradiation conditions of the pinning in the first UV irradiation unit 25 (25w to 25m). This database can, for example, be stored in... Figure 2 The storage unit 44 is used for storage. In addition, the data of the image (check chart) printed during test printing can also be stored in the storage unit 44.

[0082] Figure 4 This represents a specific example of a test image (gradient image) printed during test printing in this embodiment.

[0083] Figure 4 The gradient diagram shown represents an example in which, under the control of the control unit 40, the head unit 10, which drives the discharge of YMCK color ink, continuously forms all images of each color of YMCK and the images of each color of RGB, which become complementary colors (mixed colors), at a concentration of 5% each until a concentration of 100% is achieved.

[0084] The gradient graph described above is a graph that shows a phased change in the density of an image composed of monochrome or mixed ink ejected from the image forming unit (inkjet head 102 of head unit 10), and corresponds to the "inspection graph" of the present invention.

[0085] In this way, by printing pre-determined inspection charts (gradient charts) during test printing, it is possible to quantitatively determine the issues related to image defects and image quality degradation, thereby improving the efficiency of the operation.

[0086] In addition, Figure 4In the example shown, assuming the recording medium P used in the actual printing is white (W), the head unit 10 that ejects white (W) ink is not activated. As another example, if the recording medium P used in the actual printing is a color other than white (W), the control unit 40 can activate all head units 10 that eject the aforementioned five colors of ink to print an inspection chart (gradient chart).

[0087] When the above gradient pattern is output, the control unit 40 sets the irradiation conditions of the pinning in the first UV irradiation unit 25 (25w to 25m) to a predetermined standard value (e.g., 50% output).

[0088] Next, the operator visually identifies the test image printed on the recording medium P (in this example, a gradient of the seven colors Y, M, C, K, R, G, and B), confirming the image quality status such as bleeding, streaking, or uneven gloss. The operator then inputs the confirmed result through the input screen displayed on the operation display unit 34. The input result is stored in the aforementioned storage unit 44 of the image forming apparatus 1 as a database.

[0089] Figure 5 This is an example of a database in the storage unit 44 of the image forming apparatus 1 where the confirmation result entered by the operator via the input screen is stored (accumulated).

[0090] Furthermore, the illustrated example shows the results of printing gradient images of the aforementioned seven colors, formed using inks of the same manufacturer (Y, M, C, and K), onto four different recording media P: PET paper manufactured by Company A, PET paper manufactured by Company B, PP paper manufactured by Company C, and coated paper manufactured by Company D.

[0091] In one specific example, control unit 40 in Figure 4 After the gradient image described above is printed, the input screen is displayed on the operation display unit 34, allowing the operator to input information such as the density of the stripes in the image generated by each of the seven colors, the type of recording medium P used (differences between paper types, cloth, etc.), the manufacturer, and the product name.

[0092] exist Figure 5 In the example shown, when using PET paper manufactured by Company A as the recording medium P, it can be seen that Y (Ye), K (Bk), and G (Green) colors produce stripes in images with a concentration of 80%, M (Mg) and B (Blue) colors produce stripes in images with a concentration of 60%, R (Red) color produces stripes in images with a concentration of 50%, and C (Cy) color does not produce stripes in images with any concentration (5-100%).

[0093] In addition, Figure 5 In the example shown, when using PET paper manufactured by Company B as the recording medium P, it can be seen that Y (Ye) and C (Cy) colors produce stripes in an image with a density of 90%, G (Green) color produces stripes in an image with a density of 80%, M (Mg), K (Bk), and R (Red) colors produce stripes in an image with a density of 70%, and B (Blue) color produces stripes in an image with a density of 60%.

[0094] Furthermore, in Figure 5 In the example shown, when using PP paper manufactured by Company C as the recording medium P, it can be seen that the R (Red) color produces stripes in an image with a concentration of 100%, but the other six colors do not produce stripes in images with any concentration (5-100%).

[0095] Furthermore, in Figure 5 In the example shown, when using coated paper manufactured by Company D as the recording medium P, it can be seen that M (Mg) and B (Blue) colors produce stripes in an image with a concentration of 100%, K (Bk) color produces stripes in an image with a concentration of 90%, and the other four colors do not produce stripes in images with any concentration (5-100%).

[0096] Subsequently, during the setup operation for the print job, i.e., the actual print, the control unit 40 performs the following processing: displays a message prompting the user (operator) to select the type and manufacturer of the recording medium P to be used, as well as the desired image quality (gloss, sharpness, etc.) for the actual print, through the setup screen displayed on the operation display unit 34.

[0097] Furthermore, the control unit 40 calculates the optimal value (output, etc.) related to the irradiation conditions of the pinning in the first UV irradiation unit 25 (25w to 25m), and sets the above-mentioned optimal value so that the image quality (specified image characteristics) selected by the user (operator) through the operation display unit 34 can be realized.

[0098] For example, in the recording medium P used is Figure 5 In the case of PET paper from Company A as described above, and when the user specifies that image quality emphasizes detail reproduction (sharpness), the control unit 40 sets the output of the first UV irradiation unit 25 and the second UV irradiation unit 28 to a high level (e.g., 1.1 times the normal level) to allow the ink to cure more quickly. At this time, the control unit 40 uses the first UV irradiation unit 25m (see appropriate reference) to produce magenta (M) with a relatively low concentration, which produces poor image quality. Figure 2 The output is set higher (e.g., 1.4 times the normal value).

[0099] By making the settings described above, it is possible to achieve uniformity in the semi-cured (pre-image) state of the ink discharged onto a specific recording medium P.

[0100] Next, when the print job, i.e. the actual printing, is executed, the control unit 40 controls each part as follows.

[0101] First, as always, the control unit 40 controls the transport drive unit 51 of the transport unit 2 to start the transport of the recording medium P, so as to start the paper feeding and transport operation of the recording medium P.

[0102] Next, the control unit 40 controls the ejection of ink from the inkjet head 102 of the corresponding color from the print head unit 10. Through the above actions, an image with the color and shape specified by the printing task is formed on the recording medium P.

[0103] Furthermore, the control unit 40 controls the first UV irradiation unit 25 and the second UV irradiation unit 28 to irradiate the recording medium P on which the image is formed with UV light for pinning and formal curing, and performs the pinning (pre-image) and formal curing process of the image on the recording medium P.

[0104] At this time, the control unit 40 controls the first UV irradiation unit 25 so that each of the first UV irradiation units 25k, 25c, 25m (and 25w as needed) can be UV irradiated according to the set optimal conditions (output, UV light intensity, etc.).

[0105] Additionally, the control unit 40 can control the transport drive unit 51 as needed to change the transport speed of the recording medium P based on the transport unit 2 (such as the winding roller 23 in this example). For example, when the transport speed of the recording medium P is reduced, the amount of UV light irradiated from the first UV irradiation unit 25 can be increased compared to the case of a normal transport speed.

[0106] The recording medium P, after the aforementioned pinning and curing processes, is wound onto the winding roller 23 via the driven roller 24. Furthermore, once the required amount of image formation specified in the printing task has been achieved, the aforementioned series of processes concludes.

[0107] In addition, Figure 5 In addition to the examples shown, it is also possible to input results from various perspectives and database them, such as the results of printing test images (gradient images of multiple colors) on recording media P of the same type of paper from the same manufacturer, using inks from different manufacturers in different color combinations.

[0108] In this case, when setting up the printing task, i.e. the actual printing, the control unit 40 performs the same process as described above after prompting the user (operator) to select the manufacturer, product name, type, and manufacturer of the ink used, as well as the type and manufacturer of the recording medium P used, through the setting screen displayed on the operation display unit 34.

[0109] Thus, according to this embodiment, if the printed result of the output test image (a gradient image of multiple colors) is input once, when the same ink and recording medium P are used for formal printing again, the desired image characteristics can be reproduced without the tedious setting of pinning conditions as in the past.

[0110] Furthermore, according to the image forming apparatus 1 of this embodiment, the fixing conditions are set based on objective benchmarks and results, such as the concentration of image defects generated when printing a predetermined common inspection chart (gradient chart) using a specific ink and recording medium P. Therefore, it is possible to effectively prevent the setting of fixing conditions from becoming different for each operator.

[0111] Furthermore, according to this embodiment, when performing a printing task, based on the printing results of previously performed test prints of images (gradient images of multiple colors), the irradiation conditions of the first UV irradiation unit 25 (25w to 25m in this example) are calculated and set for each color to satisfy the specified image characteristics (image quality such as gloss and sharpness), thus preventing or suppressing unevenness in the pinning state of each color. In addition, according to this embodiment, when performing a printing task, it is possible to perform detailed processing corresponding to the customer's image quality expectations (gloss emphasis, sharpness emphasis, etc.) with fewer steps.

[0112] Furthermore, in the above structural example, the operator evaluates the printed output test image (a gradient image of multiple colors) by manually inputting the color of the image degradation (stripes in this example) and the density of the image.

[0113] As another example of the structure, it can also be configured such that, for example, an image reading unit (CCD scanner, etc., not shown) is arranged in the transport path downstream of the second UV irradiation unit 28 and upstream of the winding roller 23. Based on the reading results generated by the image reading unit, the control unit 40 performs an evaluation (judgment) on the presence or absence of stripes in the images of each concentration relative to the gradient images constituting the above-mentioned colors, and automatically inputs the evaluation results.

[0114] Furthermore, in the above structural example, the structure in which the operator inputs the evaluation of the output test image (a gradient image of multiple colors) printed on the input screen displayed on the operation display unit 34 has been described.

[0115] As another structural example, the above-mentioned input screen and subsequent setting screen can be displayed on an external terminal 200 connected to the image forming apparatus 1. Figure 2 In the example of a PC, the operator inputs an evaluation of the printed test image (a gradient image of multiple colors) through the input screen displayed on the aforementioned external terminal.

[0116] In the above structural example, the output and evaluation of a printout of a test image (a gradient image of multiple colors) are based on the premise that the ink used in the image forming apparatus 1 is changed, or the type of recording medium P used is changed.

[0117] On the other hand, the output of the test image (a gradient image with multiple colors) and the timing of the evaluation are not limited to the above; for example, they can be executed at any time based on the user's instructions.

[0118] For example, due to durability, image degradation such as stripes can easily occur when the components of the head unit 10, especially the inkjet head 102, deteriorate. Therefore, it is preferable to output test images (gradient images of multiple colors) and perform evaluation processing through user instructions (input operation).

[0119] As described above, the output and evaluation of test images (gradient images of multiple colors) are performed at any time, so that the control unit 40 can calculate a further optimal value (output, etc.) corresponding to the durability of the current device with respect to the irradiation conditions of the pinning in the first UV irradiation unit 25 (25w to 25m), and set the above-mentioned optimal value.

[0120] Furthermore, the calculated new pinning irradiation condition value can overwrite and update the existing settings. Alternatively, the new pinning irradiation condition value can be registered under a different name than the existing settings (stored in the storage unit 44), in which case the existing settings (e.g., the settings of the components of the head unit 10 in a new state) can be saved.

[0121] As another example, changes in the temperature environment can sometimes affect the expansion of the pinning points. For instance, the temperature environment may change in various situations, such as when the image forming apparatus 1 is moved to another location within the factory, when the seasons change, or when the condition of the air conditioning system at the installation location changes.

[0122] In contrast, as described above, by setting a structure that can execute the output and evaluation of test images (gradient images of multiple colors) at any time, the control unit 40 can calculate a further optimal value (output, etc.) corresponding to the current temperature environment regarding the irradiation conditions of the pinning in the first UV irradiation unit 25 (25w to 25m), and set the aforementioned optimal value.

[0123] Furthermore, as an additional structure, it can also be configured to include a print management unit that, in the event of changes in the image forming conditions or the environment surrounding the image forming apparatus 1, prompts the printing of the aforementioned test image (a gradient image of multiple colors) and processes the input of the print results.

[0124] In one specific example, the control unit 40 of the image forming apparatus 1 is equipped with the functions of the aforementioned print management unit. In this case, the control unit 40, for example, monitors the detection values ​​of a temperature and humidity sensor (not shown) within the image forming apparatus 1, and when performing the aforementioned test print, compares the results with the test results (refer to the relevant documentation as appropriate). Figure 5 Together with the temperature and humidity sensor's detection values, the ambient temperature and humidity values ​​are stored as additional information.

[0125] Furthermore, during the print job setting phase, the control unit 40 refers to or retrieves the aforementioned database stored in the storage unit 44 to determine whether the recording medium P and ink used in the print job were used in a previous test print.

[0126] At this time, if the recording medium P and ink used in the printing task have not been used in the previous test print, the control unit 40 determines that it may be unable to calculate the accurate irradiation conditions of the first UV irradiation unit 25, and displays a message indicating that a test print should be performed on the operation display unit 34.

[0127] On the other hand, if the recording medium P and ink used in this printing task have been used in previous test prints, the control unit 40 obtains the current temperature and humidity around the image forming apparatus 1 based on the detection values ​​of the temperature and humidity sensor.

[0128] Furthermore, if the ambient temperature (or humidity) around the current image forming apparatus 1 exceeds a threshold, for example, if the temperature difference relative to the temperature at the time of a previous test print exceeds 10 degrees, the control unit 40 determines that it is possible that the accurate irradiation conditions of the first UV irradiation unit 25 cannot be calculated from the print results of the previous test print, and displays a message on the operation display unit 34 indicating that a test print should be performed again.

[0129] By setting up a structure for management as described above and for issuing warnings to users, the first UV irradiation unit 25 can be set to more accurate and optimal irradiation conditions in response to changes in various image formation conditions.

[0130] In the above embodiments, the case of using a UV-curable ink as the structure for irradiating a predetermined shadow area with UV light has been described, but it is not limited to this. As another example, it is also possible to use an ink that is cured by electron beam irradiation as the structure for irradiating a predetermined shadow area with electron beams.

[0131] Furthermore, the above embodiments are merely examples illustrating specific implementations of the present invention and are not intended to limit the scope of the invention. That is, the invention can be implemented in various forms without departing from its spirit or main features.

[0132] Explanation of reference numerals in the attached drawings: 1...Image forming apparatus; 2...Transport unit; 10...Head unit (image forming unit); 21...Feed roller; 22, 24...Driven roller; 23...Winding roller; 25 (25w, 25k, 25c, 25m)...First UV irradiation unit (pre-image unit); 28...Second UV irradiation unit (fixing unit); 34...Operation display unit; 40...Control unit (setting unit, print management unit); 51...Transport drive unit; 102...Inkjet head (image forming unit); 200...External device; P...Recording medium.

Claims

1. An image forming apparatus comprising: The image forming unit ejects ink of one or more colors into the recording medium to form an image; The fixing unit has a pre-fixing unit that illuminates the formed image with energy lines to semi-solidify the image, and fixes the image onto the recording medium; The storage unit stores the printing results of test prints performed in the past, corresponding to the type of ink and the type of recording medium, according to the manufacturer information of each ink and the manufacturer information of each recording medium. as well as The setting unit, after processing the user to input the manufacturer information of the ink to be used in the printing task and the manufacturer information of the recording medium, sets the irradiation conditions of the fixing unit in the printing task based on the printing results of previously performed test prints when executing a printing task.

2. The image forming apparatus according to claim 1, wherein, The setting unit sets the irradiation energy of the energy line irradiated by the predetermined shadow area when the printing task is performed as the irradiation condition.

3. The image forming apparatus according to claim 1 or 2, wherein, The setting unit sets the illumination conditions for the corresponding predetermined image area for each type of ink discharged by the image forming unit.

4. The image forming apparatus according to claim 1 or 2, wherein, The setting unit calculates and sets the value of the irradiation conditions based on the value obtained from the printed result of the input test print.

5. The image forming apparatus according to claim 1 or 2, wherein, The setting unit prints a predetermined inspection chart during the test print and sets the irradiation conditions based on the print result.

6. The image forming apparatus according to claim 5, wherein, The inspection chart is a chart that shows the phased changes in the density of an image composed of monochrome or mixed inks discharged from the image forming section.

7. The image forming apparatus according to claim 1 or 2, wherein, The setting unit sets the illumination conditions of the fixing unit based on the printing results input by the user.

8. The image forming apparatus according to claim 1 or 2, wherein, In the test printing, the setting unit sets the illumination conditions of the fixing unit based on the reading results of the image read by the image reading unit.

9. The image forming apparatus according to claim 1 or 2, wherein, When performing the printing task, the setting unit sets the illumination conditions of the fixing unit so as to satisfy the specified image characteristics.

10. The image forming apparatus according to claim 1 or 2, wherein, The image forming apparatus includes a print management unit that performs processing to urge the execution of the test print based on image forming conditions.

Images