Image forming apparatus and drying control method

Abstract

To provide an image formation device and a drying control method which suppress uneven drying for each color, and can improve energy consumption efficiency.SOLUTION: An image formation device has an image formation part for discharging a plurality of color inks onto a recording medium, and forming an image, and a fixing part for fixing the image onto the recording medium. The fixing part includes light irradiation parts for irradiating the ink on the recording medium with a laser beam of a wavelength according to properties of each color ink so as to suppress uneven drying of each of the color inks on the recording medium. The light irradiation parts are provided on each of the color inks discharged from the image formation part, and the wavelength of the laser beam irradiated from at least one light irradiation part is different from a wavelength of a laser beam irradiated from other light irradiation part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus and a drying control method. [Background technology]

[0002] In recent years, inkjet image forming apparatuses (hereinafter referred to as inkjet image forming apparatuses), which eject ink from an inkjet head to print on a recording medium, have become widely used as devices for recording high-definition images on various recording media such as paper and fabric.

[0003] Conventionally, in inkjet image forming apparatuses, a technique is known in which ink ejected from an inkjet head onto a recording medium is irradiated with laser light to dry (fix) the ink on the recording medium (see, for example, Patent Document 1). Patent Document 2 proposes irradiating the ink on the recording medium with radiant energy such as near-infrared rays or a laser, and controlling the wavelength, intensity, and exposure time in order to dry and fix the ink. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-144403 [Patent Document 2] JP 2003-118075 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in an inkjet type image forming apparatus that performs color printing using ink of a plurality of colors, the light energy absorption characteristics differ for each color (colorant) of ink used.

[0006] In addition, actual ink products contain various substances (i.e. impurities) other than colorants, such as anti-drying agents to prevent nozzle clogging, etc., so when a laser or the like is irradiated under the same conditions (irradiation output, irradiation time, etc.), there is a problem that uneven drying can easily occur between colors and even between products.

[0007] The conventional technology has not provided any solution to the problem of uneven drying for each color. As a result, in the process of drying or fixing the ink (image) after image formation, a lot of energy is required to completely dry (fix) the image, and there has been a demand for improving the energy consumption efficiency.

[0008] An object of the present invention is to provide an image forming apparatus and a drying control method that can suppress uneven drying between colors and improve energy consumption efficiency. [Means for solving the problem]

[0009] The image forming apparatus according to the present invention comprises: an image forming unit that ejects ink of a plurality of colors onto a recording medium to form an image; a fixing unit that fixes the image on the recording medium, the fixing unit includes a light irradiation unit that irradiates the ink on the recording medium with laser light having a wavelength and output corresponding to the properties of the ink of each color so as to suppress uneven drying of the ink of each color on the recording medium; The light irradiation unit ,versus The laser light is directed only at the image of the corresponding color.

[0010] The drying control method according to the present invention comprises the steps of: A laser beam having a wavelength and an output corresponding to the properties of the ink of the plurality of colors is applied to the ink of the plurality of colors on the recording medium so that the ink of each color is prevented from drying unevenly. Picture Illuminates only the image. Effect of the Invention

[0011] According to the present invention, it is possible to suppress uneven drying between colors and improve energy consumption efficiency. [Brief description of the drawings]

[0012] [Figure 1] 1 is a side view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a block diagram showing a main functional configuration of the image forming apparatus shown in FIG. 1. [Diagram 3] 6 is a flowchart illustrating image formation control performed by a control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an inkjet image forming apparatus according to the present embodiment will be described in detail with reference to the drawings. Fig. 1 is a side view showing a schematic configuration of an image forming apparatus 1 according to the present embodiment. Fig. 2 is a block diagram showing a main functional configuration of the image forming apparatus 1.

[0014] The image forming device 1 comprises an image forming device main body 2 that forms an ink image (hereinafter referred to as an "image") on a recording medium S using an inkjet method, a paper feed section 3 arranged upstream of the image forming device main body 2 in the transport direction of the recording medium S, and a paper discharge section 4 arranged downstream of the same.

[0015] The paper feed section 3 has a function of stacking the recording media S and feeding (feeding) the stacked recording media S one by one from the top to the image forming apparatus main body 2 (see the arrow on the right side in FIG. 1). On the other hand, the paper discharge section 4 has a function as a stacker that stacks and aligns the recording media S on which images have been formed and that have been discharged from the image forming apparatus main body 2.

[0016] The image forming apparatus main body 2 includes a head unit 10 equipped with an inkjet head 102 and the like (see FIG. 2), a transport section 20 for transporting the recording medium S fed from the paper feed section 3 within the image forming apparatus main body 2, a laser irradiation section 30 for irradiating laser light onto the image forming surface of the recording medium S on which an image has been formed, and a dryer 31 for finally drying (fixing to the recording medium S) the image on the recording medium S irradiated with the laser light.

[0017] The conveying section 20 includes a plurality of conveying rollers R arranged at appropriate positions on the conveying path, an aligner 5, a first conveying belt 21 arranged below the head unit 10, a second conveying belt 25 arranged downstream of the first conveying belt 21, and the like.

[0018] The aligner 5 is disposed upstream of the first conveyor belt 21 in the conveying direction in which the recording medium S is conveyed (hereinafter simply referred to as the conveying direction). The aligner 5 has a function of aligning (correcting or correcting) the attitude and the position of the end in the width direction of the recording medium S fed from the paper feed unit 3 or the recording medium S reversed via a reversing conveying path RP described later.

[0019] The first transport belt 21 is stretched over driven rollers 22 and 24 arranged on the upstream side (right side in FIG. 1) and below in the transport direction, and a drive roller 23 arranged on the downstream side (left side in FIG. 1) in the transport direction. Under the control of the control unit 40, the drive force of a first drive motor (not shown) of a transport drive unit 51 (see FIG. 2) is transmitted to the drive roller 23, causing the first transport belt 21 to rotate counterclockwise in FIG. 1, and transport the recording medium S supplied to its placement surface (upper surface).

[0020] The second transport belt 25 is stretched over a driven roller 26 arranged on the upstream side in the transport direction (the right side in FIG. 1) and a drive roller 27 arranged on the downstream side in the transport direction (the left side in FIG. 1). Under the control of the control unit 40, the second transport belt 25 rotates counterclockwise in FIG. 1 by transmitting the driving force of a second drive motor (not shown) of a transport drive unit 51 (see FIG. 2) to the drive roller 27, and transports the recording medium S supplied to its placement surface (upper surface).

[0021] The head unit 10 ejects ink droplets (see FIG. 1) from nozzle openings provided on an ink ejection surface facing the first conveyor belt 21 onto the recording medium S transported by the first conveyor belt 21 to form an image on the recording medium S.

[0022] In one specific example, as shown in FIG. 1, four head units 10 corresponding respectively to four colors of ink, yellow (Y), magenta (M), cyan (C), and black (K), are arranged at predetermined intervals in the order of Y, M, C, and K from the upstream side in the rotation direction of the first conveyor belt 21.

[0023] Each head unit 10 includes an inkjet head 102 (see FIG. 2). The inkjet head 102 includes a pressure chamber for storing ink, a piezoelectric element provided on the wall of the pressure chamber, and a plurality of recording elements, each of which includes a nozzle. When a drive signal for deforming the piezoelectric element is input, the pressure chamber is deformed by the deformation of the piezoelectric element, changing the pressure in the pressure chamber, and ink is ejected from the nozzle communicating with the pressure chamber.

[0024] The arrangement range of the nozzles included in the inkjet head 102 in a direction perpendicular to the plane of the paper in Figure 1 (hereinafter referred to as the "orthogonal direction") covers the orthogonal width of the area on which an image is formed on the recording medium S transported by the first transport belt 21.

[0025] The head unit 10 is used with its position fixed relative to the first transport belt 21 (or the rotation axis of the drive roller 23) during image formation. That is, this image forming apparatus 1 is a single-pass type inkjet image forming apparatus.

[0026] In one specific example, ink (water-based ink) whose viscosity changes depending on the amount of energy supplied to the recording medium S, in this example, the amount of energy supplied from a fixing unit (in this example, the laser irradiation unit 30 and the dryer 31), is used as the ink ejected from the inkjet head 102 onto the recording medium S. As such a water-based ink, an ink containing a water-soluble organic solvent such as alcohol, for example, a water-based dye ink or a solvent-based ink, can be used.

[0027] Furthermore, as the recording medium S, in addition to paper such as plain paper or coated paper, various media capable of fixing the ink that has landed on the surface, such as fabric or sheet-like resin, can be used.

[0028] Next, other main functional configurations of the image forming apparatus 1 will be described, mainly with reference to Fig. 2. The image forming apparatus 1 includes a head drive section 101 and an inkjet head 102 in a head unit 10, a laser irradiation section 30, a dryer 31, a control section 40, a transport drive section 51, and an input / output interface 52. Although not shown, the image forming apparatus 1 can include an operation display section such as a touch panel for receiving user operations and displaying various settings and states of the image forming apparatus 1.

[0029] Based on the control of the control unit 40, the head driving unit 101 outputs a driving signal to the recording element of the inkjet head 102 to deform the piezoelectric element in accordance with the image data at an appropriate timing, thereby causing an amount of ink to be ejected from the nozzle of the inkjet head 102 in accordance with the pixel value of the image data.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] The ROM 43 stores various control programs and setting data executed by the CPU 41. Note that, instead of the ROM 43, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

[0034] The storage unit 44 stores print jobs (image formation instructions including various user setting information such as the number of copies) input from the external device 200 via the input / output interface 52, and image data related to the print jobs. As the storage unit 44, for example, a HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

[0035] The transport drive unit 51 supplies drive signals to the above-mentioned first drive motor, second drive motor, etc. based on a control signal supplied from the control unit 40 to rotate the first transport belt 21 and the second transport belt 25 at a predetermined speed and timing. The transport drive unit 51 also supplies drive signals to a transport motor (not shown) that rotates the transport roller R (see FIG. 1) based on a control signal supplied from the control unit 40 to rotate the transport roller R at a predetermined speed and timing.

[0036] The input / output interface 52 mediates the transmission and reception of data between the external device 200 and the control unit 40. The input / output interface 52 is configured, for example, by any one of various serial interfaces, various parallel interfaces, or a combination of these.

[0037] The external device 200 is, for example, a personal computer, and supplies print jobs, image data, and the like to the control unit 40 via the input / output interface 52 .

[0038] The laser irradiation unit 30 irradiates laser light (see the beam indicated by the symbol LB in Figure 1) onto the image forming surface of the recording medium S on which an image has been formed (i.e., ink has landed) by the image forming unit, i.e., the inkjet head 102 of the head unit 10.

[0039] In the configuration example shown in Fig. 1, the laser irradiation unit 30 constitutes a part of the fixing unit, and by irradiating the image forming surface of the recording medium S with laser light as described above, it plays a role of partially drying (the image) on the recording medium S and pre-fixing it to the recording medium S. This pre-fixing process is sometimes called "pinning".

[0040] Depending on the type of ink used, etc., the dryer 31 described below may not be provided or may not be operated when a print job is executed. In this case, the only component of the fixing unit is the laser irradiation unit 30, and the laser irradiation unit 30 plays a role of completely drying (the image) on the recording medium S and fixing it to the recording medium S by irradiating the image forming surface of the recording medium S with laser light.

[0041] Although detailed illustration is omitted, the laser irradiation unit 30 includes a light source unit such as a laser diode, a rotating polygon mirror that rotates so as to scan the laser light emitted from the light source unit in the width direction (the orthogonal direction described above) of the recording medium S, and the like, and each of these units operates under the control of the control unit 40. This configuration is a well-known configuration similar to the configuration described in, for example, Japanese Patent Application Laid-Open No. 7-144403, and therefore a detailed description is omitted. Further details of the laser irradiation unit 30 will be described later.

[0042] The dryer 31 has a heat source such as a heater and an air blower such as a fan, and these components are operated under the control of the control unit 40. The dryer 31 plays a role in completely drying (fixing to the recording medium S) the image (ink) on the recording medium S that has been pre-fixed (pinned) by the laser irradiation unit 30 by blowing hot air onto the image forming surface (upper surface) of the recording medium S that has passed through the laser irradiation unit 30.

[0043] Thus, in the configuration example shown in FIG. 1, the above-mentioned laser irradiation unit 30 and dryer 31 constitute a “fixing unit” for fixing the image (ink image) formed on the image forming surface (upper surface) of the recording medium S.

[0044] In terms of correspondence with the present invention, the laser irradiation unit 30 corresponds to a “light irradiation unit,” and the dryer 31 corresponds to a “heating unit.” The specific configurations of these units will be described later.

[0045] Next, a schematic operation of the image forming apparatus 1 when executing a print job will be described with reference to the flowchart in Fig. 3. When a print job is acquired from the above-mentioned external device 200 via the input / output interface, the image forming apparatus 1 operates as follows under the control of the control unit 40.

[0046] In step S10, the control unit 40 controls the paper feed unit 3 and the transport drive unit 51 to start the paper feed and transport operations of the recording medium S. By such control, the image forming device 1 picks up the top recording medium S (see FIG. 1) in the paper feed unit 3, and feeds the recording medium S to the transport path in the image forming device main body 2.

[0047] In the next step S20, the control unit 40 controls the aligner 5 to align (register) the recording medium S that is being conveyed upstream of the head unit 10.

[0048] Next, the control unit 40 rotates the first transport belt 21 to transport the recording medium S under the head unit 10, and controls the head unit 10 to eject ink from the inkjet head 102 of the corresponding color (step S30). Through this operation, ink droplets of the color specified in the print job are deposited on the recording medium S (see FIG. 1), and an image (ink image) of a predetermined shape is formed on the recording medium S.

[0049] In the subsequent step S40, the control unit 40 outputs a control signal to the laser irradiation unit 30, causing the laser irradiation unit 30 to irradiate (scan) laser light onto the recording medium S on which the image has been formed, thereby executing a pinning (pre-fixing) process of the image on the recording medium S.

[0050] The recording medium S after the above steps are then transported to the left in Fig. 1 by the downstream second transport belt 25. At this time, the control unit 40 drives the dryer 31 to blow hot air from the dryer 31 onto the image forming surface of the recording medium S, thereby completely drying (fixing) the image on the recording medium S (step S50).

[0051] In this drying (fixing) process, the entire recording medium S is heated, whereby the image on the recording medium S is heated and dried, and fixed to the recording medium S.

[0052] After the fixing process is completed, if the print job is set to single-sided printing, the recording medium S is transported through the transport path P1 shown in FIG. 1 and ejected to the paper ejection section 4 with the image-forming side facing up (step S60).

[0053] On the other hand, when the print job is set to double-sided printing, the control unit 40 switches a gate (not shown) to cause the recording medium S to undergo a so-called switchback operation on a reversing conveying path RP disposed on the lower side inside the image forming apparatus main body 2 via a conveying path P2 shown in Fig. 1. After such a switchback operation, the recording medium S is conveyed so that its front and rear ends, i.e., the forward and backward directions of travel, are reversed.

[0054] 1, the recording medium S is returned to the conveying path connected to the aligner 5 and the head unit 10. At this time, the recording medium S is in a state where the second side, which is the unprinted side, faces up.

[0055] The subsequent processing is the same as in the case of single-sided printing described above, with alignment by aligner 5 (step S20), image formation by head unit 10 (step S30), image pinning (pre-fixing) process (step S40) and fixing process (step S50) being performed, and then the sheet is discharged via transport path P1 to discharge section 4 with the second side facing up (step S60).

[0056] Incidentally, in an inkjet image forming apparatus that performs color printing using ink of multiple colors, uneven drying of the ink may occur due to differences in the light energy absorption characteristics of each color (colorant) of ink used.

[0057] In addition, actual ink products contain various substances (impurities, so to speak) other than colorants, such as anti-drying agents to prevent clogging of the nozzles of inkjet heads. Therefore, when energy rays such as laser light are irradiated under the same conditions (irradiation output, exposure time, etc.), there is a problem that uneven drying occurs for each color (each product).

[0058] The conventional techniques have not provided any specific solutions to the problem of uneven drying between colors.

[0059] For example, the technology described in the above-mentioned Patent Document 2 (JP Patent Publication No. 2003-118075) proposes the wavelength, intensity, and exposure time of the radiant energy source, but does not provide any solution to the problem of uneven drying between colors.

[0060] In light of these problems, the inventors conducted various experiments on the properties (color, components, etc.) of the water-based ink used in the image forming device 1 and the degree to which it dries upon laser irradiation, and as a result, came to the following findings.

[0061] First, the main components of water-based ink are water as a base, a colorant, and a water-soluble organic solvent as a penetrant. Of these, the colorant is generally a different component (substance) for each color, while water and the water-soluble organic solvent are often common components for the same type of product from the same manufacturer, even if the color changes.

[0062] On the other hand, in addition to the components mentioned above, ink may contain various other ingredients (i.e., impurities), such as anti-drying agents, pH adjusters, preservatives or anti-fungal agents, defoamers to prevent foaming, dispersants to disperse pigments in pigment inks, and oxygen scavengers to remove dissolved oxygen in the ink.

[0063] They also discovered that many of these impurities have the effect of preventing the ink from drying, that the appropriate content varies depending on the colorant (in other words, the color) of the ink, and that these impurities can ultimately cause uneven drying for each ink color.

[0064] In view of this knowledge, in the present embodiment, the laser irradiation unit 30 is configured to irradiate the image (ink image) on the recording medium S with laser light of different wavelengths corresponding to the properties of each color of ink, so as to suppress uneven drying of each color of ink on the recording medium S.

[0065] More specifically, in this embodiment, as shown in Fig. 1, a laser irradiation unit 30 is provided for each color of ink used in the head unit 10. In this example, four laser irradiation units 30 are arranged corresponding to the Y, M, C, and K inks used, and each laser irradiation unit 30 is configured to scan laser light in an orthogonal direction near the downstream of the corresponding head unit 10 in the transport direction (see Fig. 1).

[0066] It should be noted that the multiple (four in this example) laser irradiation units 30 do not need to be configured to emit laser light of all different wavelengths (i.e., four different) but only need to be configured so that the wavelength of the laser light irradiated from at least one laser irradiation unit 30 is different from the wavelength of the laser light irradiated from the other laser irradiation units 30.

[0067] In one specific example, the laser irradiation section 30 corresponding to the head unit 10 that ejects yellow (Y) ink is configured to include a semiconductor laser light source that emits blue laser light that is easily absorbed by yellow (Y) ink, and the laser irradiation section 30 corresponding to the head unit 10 that ejects magenta (M) ink is configured to include a semiconductor laser light source that emits green laser light that is easily absorbed by such magenta (M) ink.

[0068] Furthermore, the laser irradiation unit 30 corresponding to the head unit 10 that ejects cyan (C) ink is configured to include a semiconductor laser light source that emits red laser light that is easily absorbed by the cyan (C) ink. The above-mentioned configuration is for the case where a semiconductor laser light source that emits laser light that is complementary to the color of the ink used is selected.

[0069] In addition, for the laser irradiation section 30 corresponding to the head unit 10 that ejects black (K) ink, a semiconductor laser light source that emits laser light of any color can be used because black (K) ink can absorb various colors. In the example shown in Fig. 1, the laser irradiation section 30 is configured to include a semiconductor laser light source that emits red laser light, similar to the immediately upstream side.

[0070] In addition, the inventors have found that, due to the relationship between the characteristics of the various ink inclusions described above, there are inks that are difficult to dry even when using a laser light source that emits laser light of a complementary color. In order to deal with such a situation, experiments or tests are conducted in advance to select a laser wavelength that has a high drying effect for the ink containing the ink inclusion, and the laser irradiation unit 30 is provided with a laser light source that emits laser light of such a wavelength.

[0071] Generally, in the present embodiment, the "property of the ink" can be defined as the physical and chemical properties of the ink, including the color (wavelength of the color). In other words, the "property of the ink" refers to various properties that affect the drying of the ink, and includes at least the color and various inclusions contained in the ink (ink inclusions).

[0072] By adopting the above-mentioned configuration, the problem of uneven drying of each ink color can be eliminated or significantly improved.

[0073] A more specific operation of the laser irradiation unit 30 will be described. In this embodiment, each of the four laser irradiation units 30 may be configured as follows: (1) to irradiate the entire surface of the recording medium S with laser light, (2) to irradiate only the printed portion (formed image) of the recording medium S with laser light, or (3) to irradiate only the image (ink) portion of the color corresponding to each laser irradiation unit 30 with laser light.

[0074] Generally speaking, each laser irradiation unit 30 may irradiate laser light onto at least an image of a corresponding color on the recording medium S under the control of the control unit 40. From the viewpoint of strengthening prevention of curling of the recording medium S, the above configuration (2) or (3) is preferable. Also, from the viewpoint of minimizing power consumption of the laser light source, the above configuration (3) is preferable.

[0075] In the case of the above (1), that is, in the case of the configuration in which the laser light is irradiated (scanned) over the entire surface of the recording medium S, the control unit 40 performs the following process. That is, the control unit 40 outputs a control signal to the corresponding laser irradiation unit 30 so as to irradiate (scan) the laser light only onto the area of ​​the recording medium S and not irradiate other areas, for example, the area of ​​the first conveyor belt 21, based on, for example, paper size information included in the setting information of the print job.

[0076] On the other hand, in the case of the above configuration (2), that is, in which the laser light is irradiated (scanned) only onto the printed portion (formed image) of the recording medium S, the control unit 40 performs the following process. That is, the control unit 40 outputs a control signal to the corresponding laser irradiation unit 30 so as to irradiate (scan) the laser light only onto the image area on the recording medium S, and not irradiate other areas, for example, non-printed areas of the recording medium S, based on image area information included in the input image information of a print job, for example.

[0077] Furthermore, in the case of the above configuration (3), that is, in the case of a configuration in which the laser light is irradiated (scanned) only onto the ink (image) of the corresponding color among the image formed on the recording medium S, the control unit 40 performs the following process. That is, similar to the above, the control unit 40 outputs a control signal to the corresponding laser irradiation unit 30 so as to irradiate (scan) the laser light only onto the image area of ​​the corresponding color on the recording medium S based on the image area information included in the input image information of the print job, and not to irradiate the laser light onto image areas of other colors and non-printed parts.

[0078] In any of the above configurations, the ink (image) on the recording medium S irradiated with the laser light scanned by the laser irradiation unit 30 absorbs the energy of the laser light and is heated to dry and be fixed to the paper.

[0079] It is also possible to use infrared or near-infrared light to dry the ink, but in this case, there is a problem that the recording medium S (paper, etc.) is more likely to curl as it absorbs the light and dries.

[0080] For this reason, in this embodiment, a semiconductor laser light source in which light is not easily absorbed by the recording medium S (paper, etc.) is provided as the laser irradiation unit 30. From the viewpoint of further preventing curling of the recording medium S, the laser irradiation unit 30 may be configured as a laser scanning type (scanning type laser light source) as described above, and the control unit 40 may be controlled so that the laser light is irradiated only onto the image (ink) portion on the recording medium S.

[0081] With the above-mentioned configuration, it is possible to keep costs low even when multiple laser irradiation units 30 are provided. Furthermore, with the above-mentioned configuration, it is possible to emit a thinner light beam compared to surface-emitting light sources such as VCSELs (Vertical Cavity Surface Emitting Lasers) and LEDs (Light Emitting Diodes).

[0082] Here, the advantage of being able to emit a thin light beam is that, for example, even if the gap between the head units 10 of each color is narrow, the laser light can be scanned in the gap area in the orthogonal direction (the width direction of the recording medium S) described above, and the image and therefore the ink of the corresponding color can be irradiated (see Figure 1).

[0083] In one specific example, when the ink used in the image forming device 1 is changed to a product of another manufacturer or to an ink of the same manufacturer that contains different ingredients, an inspection is performed in a trial run mode, such as the one described below, before executing a print job (hereinafter also referred to as "actual printing").

[0084] In the trial operation mode, the image forming device 1 ejects ink from each head unit 10 so that solid images of each color of YMCK ink are adjacent to each other on the recording medium S, and performs a pinning (pre-curing) process in each corresponding laser irradiation section 30, and discharges the recording medium S on which the test chart is printed to the paper discharge section 4 without driving the downstream dryer 31.

[0085] Here, if the inks of the various colors (especially the colors at the boundaries) of the solid image that constitutes the test chart on the discharged recording medium S are mixed, the output of the corresponding laser irradiation unit 30 is increased and the above inspection is performed again, and if the colors of the solid image on the recording medium S no longer mix, the settings are saved and the actual printing is performed.

[0086] The setting of the output of the laser irradiation unit 30 can be changed by displaying a user setting screen on the above-mentioned operation display unit (such as a touch panel).

[0087] By carrying out the above-mentioned inspections and settings in advance, the performance of the pre-curing process and thus the fixing process by the laser irradiation unit 30 for the inks of various components that will actually be used can be ensured, so that the drying of the ink and thus the fixing quality to the recording medium can be significantly improved.

[0088] When an actual image to be used in actual printing is printed and the above-mentioned test run mode is carried out, the standard may be whether or not the ink of each color has completely dried (fixed).

[0089] That is, in the above-mentioned trial operation mode, the image forming apparatus 1 ejects ink of each color, for example YMCK, to cause ink droplets to land on the recording medium S to form an image to be printed in the actual printing, and pins (pre-cures) the ink in each corresponding laser irradiation section 30, and discharges the recording medium S to the discharge section 4 without operating the downstream dryer 31.

[0090] If the image (ink image) on the discharged recording medium S is not completely dry, the output of the laser irradiation unit 30 corresponding to the color that is not completely dry is set high and the above-mentioned test in the trial operation mode is repeated. Then, when the ink of each color is completely dry (fixed), the settings for the laser irradiation unit 30 are saved and actual printing is performed according to the settings.

[0091] By carrying out such inspections and settings in advance, the output of the dryer 31 can be reduced to zero or to a minimum during regular printing, improving energy efficiency. In addition, minimizing the output of the dryer 31 can contribute to suppressing curling of the recording medium S.

[0092] In this manner, according to the present embodiment, which is configured to irradiate laser light of different wavelengths according to the properties of the multiple colors of ink onto the image forming surface of the recording medium S on which multiple colors of ink have landed, in order to suppress uneven drying of the ink, it is possible to suppress uneven drying of each color and improve energy consumption efficiency.

[0093] In addition, the above-mentioned embodiments are merely examples of the embodiment of the present invention, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be embodied in various forms without departing from the gist or main characteristics of the present invention. [Explanation of symbols]

[0094] 1. Image forming device 2. Image forming device main body 3 Paper feed section 4 Paper ejection section 5 Aligners 10 Head unit (image forming section) 20 Conveyor section 21 First conveyor belt 23 Drive roller 25 Second conveyor belt 26 Driven roller 27 Drive roller 30 Laser irradiation section (light irradiation section, fixing section) 31 Dryer (heating section, fixing section) 40 Control section 51 Conveyor drive unit 101 Head drive unit 102 Inkjet head RP Reversing conveyor R Conveyor Roller S Recording medium

Claims

1. an image forming unit that ejects ink of a plurality of colors onto a recording medium to form an image; a fixing unit that fixes the image on the recording medium, the fixing unit includes a light irradiation unit that irradiates the ink on the recording medium with laser light having a wavelength and output corresponding to the properties of the ink of each color so as to suppress uneven drying of the ink of each color on the recording medium; The light irradiation unit irradiates the laser light only onto the image of a corresponding color. Image forming device.

2. the light irradiation unit is provided for each color of the ink ejected from the image forming unit, and a wavelength of the laser light irradiated from at least one of the light irradiation units is different from a wavelength of the laser light irradiated from the other light irradiation units; The image forming apparatus according to claim 1 .

3. the fixing unit further includes a heating unit configured to heat the recording medium irradiated with the laser light by the light irradiating unit; 3. The image forming apparatus according to claim 1 or 2.

4. the light irradiation unit is a scanning laser light source that scans the laser light on the image forming surface of the recording medium, The image forming apparatus according to claim 1 .

5. The light irradiation unit includes a semiconductor laser light source that emits the laser light. The image forming apparatus according to claim 1 .

6. The properties of the ink include color and ink inclusions that affect the drying of the ink. The image forming apparatus according to claim 1 .

7. A laser beam having a wavelength and output corresponding to the properties of the ink of the plurality of colors is irradiated only on the image of the corresponding color on the recording medium on which the ink of the plurality of colors has landed, so that unevenness in drying of the ink of each color is suppressed. Drying control method.

Images