JP2019059075A - Droplet discharge device and droplet discharge program - Google Patents

Abstract

To suppress a failure in drying a droplet on a recording medium.SOLUTION: A droplet discharge device 20 includes an ink head 2 for discharging ink to a sheet P. The droplet discharge device controls content of an infrared absorbent contained in ink discharged from the ink head 2 in accordance with an image formation attribution that is used when forming an image on a sheet P, and irradiates the sheet P to which the ink is discharged with infrared light.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a droplet discharge device and a droplet discharge program.

  In Patent Document 1, a plurality of laser light sources for irradiating the laser onto the droplets discharged onto the recording medium by discharging means for discharging the droplets onto the recording medium and drying the droplets are formed in a two-dimensional manner. A drying unit including a laser light source group arranged, and a control unit laser light source group having a plurality of laser light source groups arranged along the conveyance direction of the recording medium as a control unit; Control means for controlling the drying means by using the irradiation profile of the laser which is divided so as to be arranged along the intersecting direction crossing each other and which is set for each of the divided control unit laser light source groups; With respect to the test image formed on the recording medium by the droplets discharged by the means, the laser is changed by the drying means using the irradiation profile different for each control unit laser light source group And d) setting means for setting the irradiation profile for each of the plurality of laser light sources included in the laser light source group, the irradiation profile being irradiated and the evaluation of the test image irradiated by the laser being equal to or higher than a reference It is disclosed.

JP, 2016-112781, A

  Some image forming apparatuses using an inkjet method include a laser irradiation device that irradiates laser light to ink ejected onto a recording medium to dry the ink and fix an image on the recording medium.

  In such an image forming apparatus, for example, when the attribute relating to image formation, such as the type of recording medium, changes in the ease of drying of the ink on the recording medium, the intensity of the laser beam applied to the ink is controlled. In some cases, the occurrence of drying failure of the ink may be suppressed.

  On the other hand, the ink used in such an image forming apparatus contains an infrared absorber, which absorbs infrared components contained in laser light and converts it into heat, in a predetermined amount so that the ink can be easily dried. There is.

  However, the cost of the infrared absorbing agent contained in the ink consumed to form an image per unit number is more expensive than the electricity cost of the power consumed by the laser irradiation apparatus which maximizes the laser light intensity. Tend to be

  Therefore, it is preferable to suppress the drying failure of the ink by controlling the content of the infrared absorber contained in the ink, rather than controlling the intensity of the laser light to suppress the drying failure of the ink.

  The present invention can suppress the drying failure of the droplets on the recording medium, as compared with the case where the image is formed on the recording medium using the droplets in which the content of the infrared absorbing agent is predetermined. An object of the present invention is to provide a discharge device, a droplet discharge program, and an image forming apparatus.

  In order to achieve the above object, the invention of an image forming apparatus according to claim 1 is characterized in that discharge means for discharging droplets onto a recording medium, and an image forming attribute used when forming an image on the recording medium, The apparatus comprises: control means for controlling the content of the infrared absorbent contained in the droplets discharged from the discharge means; and irradiation means for irradiating the recording medium from which the droplets have been discharged with infrared light.

  In the invention according to claim 2, even when the droplet is irradiated with the infrared light of a predetermined intensity, the control means causes an attribute which causes a change in the degree of drying of the droplet as the image forming attribute. And control the content of the infrared absorbent contained in the droplets discharged from the discharge means in accordance with the image formation attribute.

  In the invention according to claim 3, the control means acquires the ratio of the area where the droplet is discharged to the unit area of the recording medium as the image formation attribute, and the infrared absorption as the ratio becomes smaller than a reference ratio The control is performed such that the content of the agent is smaller than the reference content, and the content of the infrared absorber is made larger than the reference content as the ratio becomes larger than the reference ratio.

  According to a fourth aspect of the present invention, in the case where there are a plurality of regions having different proportions in the recording medium, the control means includes the infrared absorber contained in the droplets discharged in each of the plurality of regions. Control is performed to set the amount in accordance with the ratio of the region having the highest ratio among the plurality of regions.

  In the invention according to claim 5, the control means performs control of identifying the ratio from the type of an image formed on the recording medium.

  In the invention according to claim 6, the control means acquires the permeability of the droplet to the recording medium as the image forming attribute, and the infrared absorber is contained as the permeability of the droplet becomes higher than the standard permeability. The amount is controlled to be less than the reference content, and the content of the infrared absorbing agent is controlled to be higher than the reference content as the droplet permeability becomes lower than the reference permeability.

  In the invention according to claim 7, the control means controls to distinguish the permeability of the droplet from the type of the recording medium.

  In the invention according to claim 8, the control means acquires the conveyance speed of the recording medium as the image formation attribute, and the content of the infrared absorbent is increased as the conveyance speed of the recording medium becomes slower than the reference conveyance speed. The control is performed to reduce the content of the infrared absorbing agent to be higher than the reference content as the conveyance speed of the recording medium becomes smaller than the reference content and the conveyance speed of the recording medium becomes higher than the reference conveyance speed.

  In the invention according to claim 9, the control means acquires, as the image forming attribute, the temperature of the portion where the infrared light is irradiated to the recording medium, and the infrared absorber as the temperature becomes higher than a reference temperature. The content of the infrared absorber is controlled to be smaller than the reference content, and the content of the infrared absorber is made to be larger than the reference content as the temperature becomes lower than the reference temperature.

  In the invention according to claim 10, the control means acquires, as the image formation attribute, the humidity of the portion where the infrared light is irradiated to the recording medium, and the infrared absorber as the humidity becomes lower than a reference humidity. The content of the infrared absorber is controlled to be smaller than the reference content, and the content of the infrared absorber is made to be larger than the reference content as the humidity becomes higher than the reference humidity.

  In the invention according to claim 11, the control means acquires the thickness of the recording medium as the image forming attribute, and the content of the infrared absorber as a reference content as the thickness of the recording medium becomes thicker than a reference value Control is performed to increase the content of the infrared absorber more than the reference content as the thickness of the recording medium becomes thinner than the reference value.

  In the invention according to claim 12, the control means includes the infrared absorber set according to the image formation attribute among a plurality of storage members in which droplets having different contents of the infrared absorber are stored in advance. Control is performed to supply droplets from the storage member including the amount to the discharge means.

  In the invention according to claim 13, the control means mixes the droplets stored in the plurality of storage members, and the liquid containing the content of the infrared ray absorbent set according to the image formation attribute from the discharge means Control is made to eject drops.

  In the invention as set forth in claim 14, the color of the droplet containing the infrared absorber is a transparent color.

  The invention according to a fifteenth aspect comprises an additional discharge means for discharging, onto the recording medium, colored droplets not containing the infrared absorbent, and the control means is arranged on the recording medium discharged from the additional discharge means. The discharge means is controlled so that the transparent color droplets are superimposed and discharged on the colored droplets.

  The invention of a droplet discharge program according to claim 16 causes a computer to function as control means of the droplet discharge device according to any one of claims 1 to 15.

  According to the first aspect of the present invention, the drying failure of the droplets on the recording medium is made in comparison with the case where the image is formed on the recording medium using the droplets in which the content of the infrared absorbing agent is predetermined. The effect is that it is possible to suppress

  According to the second aspect of the present invention, the image forming cost per unit number can be reduced as compared with the case of controlling the intensity of the infrared light irradiated to the droplet.

  According to the third aspect of the present invention, it is possible to control the content of the infrared absorber contained in the droplets in accordance with the ratio of the area where the droplets are discharged to the unit area of the recording medium.

  According to the fourth aspect of the present invention, it is possible to suppress the drying failure of the droplet in the region where the ratio of the region where the droplet is discharged to the unit area is the highest.

  According to the fifth aspect of the present invention, the ratio can be obtained without measuring the ratio of the area where the droplet is discharged to the unit area.

  According to the sixth aspect of the invention, the content of the infrared absorbing agent contained in the droplet can be controlled according to the permeability of the droplet to the recording medium.

  According to the seventh aspect of the present invention, the permeability can be obtained without measuring the permeability of the droplet to the recording medium.

  According to the eighth aspect of the present invention, the content of the infrared absorber contained in the droplets can be controlled according to the transport speed of the recording medium.

  According to the ninth aspect of the present invention, the content of the infrared absorber contained in the droplet can be controlled in accordance with the temperature of the portion where the recording medium is irradiated with the infrared light.

  According to the tenth aspect of the invention, the content of the infrared absorbing agent contained in the droplet can be controlled in accordance with the humidity of the portion where the recording medium is irradiated with the infrared light.

  According to the invention of claim 11, it is possible to control the content of the infrared absorbing agent contained in the droplet according to the thickness of the recording medium.

  According to the invention of claim 12, each time an image is formed, the droplet is transferred to the recording medium after receiving an instruction to form an image, as compared with the case where the amount of the infrared absorber mixed in the droplet is adjusted. It has the effect that the time required to discharge can be shortened.

  According to invention of Claim 13, it has an effect that the droplet which contains the infrared absorber of the quantity different from content of the infrared absorber in the droplet stored by the storage member can be generated.

  According to the invention of claim 14, it is possible to suppress the deterioration of the image quality as compared with the case where the infrared absorbent is mixed in the colored droplets.

  According to the invention of claim 15, it is possible to adjust the amount of the infrared absorbent discharged to different images on the same recording medium.

FIG. 1 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus. It is a figure which shows the example of a change of the dryness degree of ink with respect to content of an infrared rays absorbent. FIG. 2 is a diagram showing an example of a main configuration of an electric system in the image forming apparatus. 5 is a flowchart illustrating an example of the flow of droplet discharge processing; It is a figure which shows the example of a change of the dryness degree of the ink with respect to image coverage. It is a flowchart which shows the modification of the flow of the droplet discharge process which forms the several image from which image coverage differs. It is a figure which shows the example of a change of the dryness degree of the ink with respect to the permeability of the ink. It is a figure which shows the example of a change of content of the infrared rays absorbent contained in the ink with respect to the conveyance speed of a paper. It is a figure which shows the example of a change of the dryness degree of the ink with respect to temperature. It is a figure which shows the example of a change of the dryness degree of the ink with respect to humidity. FIG. 7 is a diagram showing an example of change in the degree of drying of the ink with respect to the thickness of the sheet. FIG. 6 is a diagram showing an example of another schematic configuration showing main components of the image forming apparatus. FIG. 6 is a diagram showing an example of another schematic configuration showing main components of the image forming apparatus. FIG. 2 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus that ejects a transparent color ink. 5 is a flowchart showing an example of the flow of droplet discharge processing for discharging transparent ink. It is a figure showing an example of the schematic structure which showed the main composition parts of the image forming device provided with a plurality of laser irradiation devices.

  Hereinafter, the present embodiment will be described with reference to the drawings. Note that components and processes having the same function are given the same reference numerals throughout the drawings, and redundant description will be omitted. In the present embodiment, with respect to color display, yellow is represented by “Y”, magenta by “M”, cyan by “C”, black by “K”, and transparent by “T”. Do.

  When it is necessary to distinguish and describe each member or image for each color, color codes (Y, M, C, K, T) corresponding to each color are added to the end of the name or code to distinguish them. On the other hand, when collectively describing each member or image without distinguishing it for every color, the color code added to the end of a name or a code | symbol is abbreviate | omitted.

  FIG. 1 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus 100 for forming an image on a sheet P by an inkjet method.

  The image forming apparatus 100 includes a droplet discharge device 20 that discharges ink, which is an example of a droplet, onto a sheet P, and a transport roll 22 that transports the sheet P. The image forming apparatus 100 further includes a temperature sensor 14 and a humidity sensor 16 that respectively measure the temperature and humidity at the irradiation position of the sheet P to which the laser light is irradiated by the laser irradiation device 12 included in the droplet discharge device 20. And an operation panel 18 that functions as an interface with a user who uses the image forming apparatus 100. The image forming apparatus 100 further includes a control device 10 which is an example of a control unit that forms an image corresponding to the image data received from the user on the sheet P.

  The droplet discharge device 20 includes ink heads 2Y, 2M, 2C, and 2K, which are an example of a discharge unit that discharges ink colored in corresponding colors to the paper P for each color of YMCK called process color. And an ink head driving device 4 for driving the ink head 2 of each color. In addition, the droplet discharge device 20 includes an ink cartridge 6Y, 6M, 6C, 6K, which is an example of a storage member for storing ink for each color of YMCK, and an infrared absorber (hereinafter referred to as "IR (Infrared) agent") And an IR cartridge 8 which is an example of a storage member for storing the Furthermore, the droplet discharge device 20 includes a laser irradiation device 12 that irradiates the ink on the sheet P with laser light.

  The ink includes an aqueous ink, an oil-based ink which is an ink from which a solvent is evaporated, an ultraviolet curable ink, and the like, but in the present embodiment, the aqueous ink is used. In the present embodiment, the term “ink” simply means “water-based ink”.

  The ink of each color of Y, M, C, K, K discharged from the ink head 2 is supplied from the ink cartridge 6 storing the ink of the corresponding color through the ink head driving device 4.

  At this time, the ink head driving device 4 mixes the IR agent supplied from the IR cartridge 8 with the ink of each color of YMCK discharged from the ink head 2. The amount of IR agent mixed in the ink of each color by the ink head drive 4 follows the control of the controller 10.

  Further, the ink head driving device 4 drives the ink head 2 of each color so as to discharge the ink onto the sheet P on the conveyance path at the ink discharge position instructed from the control device 10 and the ink discharge timing. Form an image.

  The sheet P is transported on the transport path along the transport direction indicated by the arrow AR by the transport roll 22 which is an example of a transport apparatus that transports the sheet P. In the present embodiment, as an example, the recording medium on which an image is formed will be described as the sheet P. However, as long as the ink is fixed, a recording medium using a material other than paper may be used.

  When the sheet P on which the image is formed is conveyed to a position facing the laser irradiation surface of the laser irradiation device 12, the laser light is irradiated from the laser irradiation device 12.

  Under the present circumstances, since the IR agent is contained in the ink which comprises an image, energy (dry energy used in order to dry an ink by IR component absorbing in the infrared component contained in a laser beam and converting into heat) ) Is generated, whereby the drying of the ink is promoted and the image is fixed on the paper P.

  The operation panel 18 includes an interface with a user who uses the image forming apparatus 100. Specifically, it includes a reception unit for receiving settings and instructions related to image formation from the user, and a display unit for notifying the user of the operation status of the image forming apparatus 100.

  The control device 10 controls the droplet discharge device 20, the laser irradiation device 12, the temperature sensor 14, the humidity sensor 16, and the operation panel 18 in accordance with the formation conditions for image formation set by the user, and receives from the user An image corresponding to the image data is formed on the sheet P.

  In FIG. 1, an alternate long and short dash line indicates a control path by the controller 10, and a dotted line indicates an ink supply path.

  In such an image forming apparatus 100, even when the intensity of the laser light is not changed, the ink is easily dried in unit time by changing the content of the IR agent contained in the ink of each color ("drying property" Also change). Note that the higher the drying property of the ink, the easier it is to dry the ink, and the high and low drying state is referred to as the “drying degree”.

  FIG. 2 is a diagram showing an example of change in the degree of drying of the ink with respect to the content of the IR agent contained in the ink.

  2A shows the content of the IR agent contained in the ink and the ultimate temperature of the ink when the laser irradiation device 12 irradiates the same volume of ink with the laser light of the same intensity for the unit time. Is a diagram showing an example of the relationship between Further, FIG. 2B shows the relationship between the content of the IR agent contained in the ink and the drying property of the ink when the laser irradiation device 12 irradiates the same volume of ink with the same intensity for a unit time. Is a diagram illustrating an example of

  In this case, as shown in FIG. 2A, it can be seen that the ultimate temperature of the ink increases as the content of the IR agent contained in the ink increases. Therefore, as shown in FIG. 2B, as the content of the IR agent contained in the ink increases, the drying property of the ink increases.

  On the other hand, the drying property of the ink on the sheet P changes not only by the change of the content of the IR agent contained in the ink but also by the forming condition of the image used when forming the image on the sheet P. Therefore, under the image forming conditions set by the user, in order to suppress drying defects such as overdrying or insufficient drying of the image formed on the sheet P, the IR agent contained in the ink according to the image forming conditions It is sufficient to control the content of

  Each item that defines the formation conditions of the image is called an "attribute", and among the attributes that define the formation conditions of the image, an attribute that causes a change in the degree of dryness of the ink is called "image formation attribute".

  Hereinafter, the image forming apparatus 100 for controlling the content of the IR agent contained in the ink ejected from the ink head 2 in accordance with the image forming attribute at the time of forming an image will be described in detail.

  FIG. 3 is a diagram showing an example of a main configuration of an electric system in the image forming apparatus 100 in which the control device 10 is configured by the computer 40.

  The computer 40 includes a central processing unit (CPU) 41, a read only memory (ROM) 42, a random access memory (RAM) 43, a non-volatile memory 44, and an input / output interface (I / O) 45. The CPU 41, the ROM 42, the RAM 43, the non-volatile memory 44, and the I / O 45 are connected to one another via the bus 46.

  The type of operation system used by the computer 40 is not limited, and any operation system may be used or may not be used.

  The nonvolatile memory 44 is an example of a storage device in which the stored information is maintained even if the power supplied to the nonvolatile memory 44 is cut off. For example, a semiconductor memory is used, but a hard disk may be used.

  On the other hand, to the I / O 45, for example, an ink head drive device 4 for driving the ink head 2 of each color, a laser irradiation device 12, an operation panel 18, a temperature sensor 14, a humidity sensor 16, and a transport roll 22 are connected It is controlled. The devices connected to the I / O 45 are not limited to these, and other devices such as a communication unit that connects to a communication line such as the Internet and transmits / receives data to / from an information device connected to the communication line may be used. It may be connected.

  Next, the operation of the image forming apparatus 100 for controlling the content of the IR agent contained in the ink ejected from the ink head 2 in accordance with the image forming attribute at the time of forming an image will be described.

  FIG. 4 is a flowchart showing an example of the flow of the droplet discharge process performed by the CPU 41 of the image forming apparatus 100.

  The droplet discharge program that defines the droplet discharge process is stored in advance in, for example, the ROM 42 of the image forming apparatus 100. The CPU 41 of the image forming apparatus 100 reads a droplet discharge program stored in the ROM 42 and executes a droplet discharge process when an image formation instruction for forming an image designated on a sheet P is received from a user, for example.

  When the droplet discharge process according to the present embodiment is performed, the intensity of the laser beam emitted from the laser irradiation device 12 is not changed. Specifically, the laser irradiation device 12 irradiates the laser light at the maximum output of the laser irradiation device 12.

  A user who uses the image forming apparatus 100 transmits, to the image forming apparatus 100, image data as an image formation target along with the image forming conditions when forming an image. The image forming conditions are input from a driver screen of the image forming apparatus 100 executed by an information device such as a computer connected via a communication line, for example, but may be input from the operation panel 18.

  The image forming apparatus 100 stores the forming conditions of the input image in the RAM 43, and generates bitmap data (raster data) obtained by decomposing the received image data into each component of YMCK, and stores the data in the RAM 43.

  Therefore, in step S10, the CPU 41 acquires an image formation attribute from at least one of the image formation conditions and raster data stored in the RAM 43.

  Although various types of attributes exist in the image formation attribute, "image coverage" is acquired as an example here. The image coverage is the ratio of the area where ink is ejected to the unit area in the image forming area of the sheet P. Specifically, since one ink droplet corresponds to the pixel of the image, the unit of the sheet P It is represented by the number of pixels per area. Therefore, by referring to the raster data stored in the RAM 43, image coverage can be obtained.

  FIG. 5 is a diagram showing an example of change in the degree of dryness of the ink with respect to the image coverage.

  In FIG. 5, in FIG. 5A, it is necessary to dry the image coverage and the ink represented by the image coverage when the laser irradiation device 12 irradiates the ink with the laser beam having the maximum intensity. It is a figure which shows an example of a relation with drying energy. As shown in FIG. 5A, as the image coverage increases, the required drying energy also increases.

  Further, in FIG. 5B, in order to obtain the image coverage and the drying energy shown in FIG. 5A in each image coverage when the laser irradiation device 12 irradiates the ink with the laser beam of the maximum intensity for the same time. It is a figure which shows an example of a relationship with content of IR agent required for.

  The change in the degree of dryness of the ink relative to the image coverage shown in FIG. 5 is an example, and may not necessarily be in a proportional relationship.

  Since the amount of ink per unit area increases as the image coverage increases, as shown in FIG. 5A, it can be seen that the drying energy required for drying increases as the image coverage increases. Therefore, as shown in FIG. 5B, it is necessary to increase the content of the IR agent contained in the ink as the image coverage increases.

  Therefore, the non-volatile memory 44 of the image forming apparatus 100 corresponds to the range of the predetermined image coverage as a reference (reference image coverage range) obtained from the graph of FIG. 5B and the reference image coverage range. The content of the selected IR agent is stored. Specifically, a predetermined range including the image coverage Cov2 set as a standard value of the image coverage in the image forming apparatus 100 is set as the reference image coverage range, and the image coverage Cov2 is set to the reference image coverage range. Correspond to the content of IR agent. Further, the graph of FIG. 5B is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the reference image coverage range is an example of the reference content.

  Then, in step S20, the CPU 41 determines whether the image coverage acquired in step S10 is included in the reference image coverage range.

  If the acquired image coverage is included in the reference image coverage range, the process proceeds to step S30.

  In this case, since the acquired image coverage is included in the reference image coverage range, in step S30, the CPU 41 sets the content of the IR agent included in the ink as the reference content.

  On the other hand, if the determination processing in step S20 is negative, that is, if it is determined that the acquired image coverage is not included in the reference image coverage range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, in step S40, as in the image coverage Cov1 of FIG. 5B, when the acquired image coverage is smaller than the lower limit value of the reference image coverage range, the CPU 41 refers to the graph of FIG. As the image coverage becomes smaller than the lower limit value of the reference image coverage range, the content of the IR agent included in the ink is set to be lower than the reference content.

  Conversely, when the acquired image coverage is larger than the upper limit value of the reference image coverage range as in the image coverage Cov3 of FIG. 5B, the CPU 41 refers to the graph of FIG. 5B and the acquired image coverage is The content of the IR agent included in the ink is set to be higher than the reference content as it becomes larger than the upper limit value of the reference image coverage range.

  In step S50, the CPU 41 controls the ink head driving device 4 so that the IR agent having the content set in step S30 or step S40 is contained in the ink with respect to the entire amount of ink of each color ejected from the ink head 2. . Then, the CPU 41 discharges the ink containing the set amount of the IR agent from the ink head 2 and forms an image on the sheet P.

  In step S60, the CPU 41 controls the laser irradiation device 12 to irradiate the ink forming the image formed on the sheet P with the laser beam of maximum intensity from the laser irradiation device 12 and fix the image on the sheet P. Thus, the droplet discharge process shown in FIG. 4 is completed.

  In step S20, it is determined whether the acquired image coverage is included in the reference image coverage range, but it is determined whether the acquired image coverage matches the predetermined reference image coverage. It is also good. The “reference image coverage” is a predetermined image coverage to be compared, and it may be set to any value, but within a range of more than 10% and less than 100%, which is called so-called moderate image coverage. , Often set the reference image coverage.

  In this case, according to FIG. 5B, the content of the IR agent corresponding to the reference image coverage is set as the reference content, and stored in the non-volatile memory 44.

  If the acquired image coverage is different from the reference image coverage, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph in FIG. 5B, and if the acquired image coverage is smaller than the reference image coverage, IR is included in the ink as the acquired image coverage becomes smaller than the reference image coverage. If the content of the agent is set smaller than the reference content and the acquired image coverage is larger than the reference image coverage, the content of the IR agent to be included in the ink is referred to as the acquired image coverage becomes larger than the reference image coverage. Set more than content.

  When a plurality of images different in image coverage are formed on the sheet P, droplet discharge processing different from the droplet discharge processing shown in FIG. 4 is performed.

  FIG. 6 is a flowchart showing a modification of the flow of the droplet discharge process performed by the CPU 41 of the image forming apparatus 100.

  The flowchart shown in FIG. 6 differs from the flowchart shown in FIG. 4 in that steps S12 and S14 are added.

  When image coverage is acquired as an image formation attribute in step S10 of FIG. 6, the CPU 41 determines whether or not a plurality of images having different image coverage exist on the same sheet P in step S12. When the determination process of step S12 is affirmation determination, it transfers to step S14.

  In step S14, the CPU 41 obtains the largest image coverage among the image coverages corresponding to each of the plurality of images, and determines in step S20 whether the largest image coverage is included in the reference image coverage range. .

  That is, the content of the IR agent contained in the ink is set in accordance with the maximum image coverage.

  On the other hand, when the determination process of step S12 is a negative determination, it transfers to step S20, without performing step S14. In this case, in step S20, the CPU 41 determines whether the image coverage acquired in step S10 is included in the reference image coverage range, and executes the same process as the droplet discharge process shown in FIG.

  Also in this case, it goes without saying that the acquired image coverage may be compared with the reference image coverage instead of the reference image coverage range.

  Further, in step S10 shown in FIG. 4 and FIG. 6, the image coverage is acquired with reference to raster data, but the image coverage is also acquired from other than raster data.

  For example, since the image coverage in the case of forming an image such as a photo or a poster on the paper P tends to be larger than the image coverage in the case of forming a character on the paper P, the image coverage allows the user to form an image It is identified from the type of image set at the time.

  Therefore, the representative image coverage in the case where the type of image is a photograph and the representative image coverage in the case where the type of image is a character are stored in advance in the non-volatile memory 44, and By acquiring the corresponding image coverage from the non-volatile memory 44, the image coverage can be obtained without measuring the image coverage from the raster data.

<Control of IR agent content by permeability>
The image formation attribute also includes the permeability of the ink in the paper P. Therefore, with reference to FIG. 4, a method of controlling the content of the IR agent in the case where the ink permeability of the paper P is acquired as the image formation attribute in step S10 will be described here. The penetration rate of the ink of the paper P to be used is assumed to be preset by the user and stored in the RAM 43. Hereinafter, the ink penetration rate of the paper P will be simply referred to as “ink penetration rate”.

  FIG. 7 is a diagram showing an example of change in the degree of drying of the ink with respect to the permeability of the ink.

  In FIG. 7, FIG. 7A shows the ink permeability and the drying energy required to dry the ink when the same amount of ink is irradiated with the laser beam of maximum intensity from the laser irradiation device 12. It is a figure which shows an example of the relationship of.

  Further, FIG. 7 (B) shows the ink permeability and each permeability in FIG. 7 (A) when the laser irradiation device 12 irradiates the laser light of the maximum intensity to the ink for the same time and the same amount. It is a figure which shows an example of a relation with content of IR agent required in order to obtain dry energy.

  The change in the degree of dryness of the ink relative to the permeability of the ink shown in FIG. 7 is an example, and may not necessarily be proportional.

  The lower the ink permeability, the easier it is for the ink to stay on the surface of the paper P. Therefore, as shown in FIG. 7A, it can be seen that the drying energy required for drying increases as the ink permeability decreases. . Therefore, as shown in FIG. 7B, it is necessary to increase the content of the IR agent included in the ink as the ink permeability decreases.

  The non-volatile memory 44 of the image forming apparatus 100 corresponds to the range of the standard ink permeability as a standard (standard permeability range) obtained from the graph of FIG. 7B and the standard permeability range. The content of the selected IR agent is stored. Specifically, a predetermined range including the permeability Per2 set as the standard value of the permeability of the ink in the paper P is set as the standard permeability range, and the permeability Per2 is set to the standard permeability range. Correspond to the content of IR agent. The graph of FIG. 7B is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the standard permeability range is an example of the standard content.

  Then, in step S20, the CPU 41 determines whether or not the ink permeability obtained in step S10 is included in the reference permeability range. Here, it is assumed that the penetration rate of the ink is set in advance by the user via the driver screen or the operation panel 18.

  When the permeability of the obtained ink is included in the standard permeability range, the process proceeds to step S30, and the content of the IR agent to be included in the ink is set to the standard content.

  On the other hand, if the determination in step S20 is negative, that is, if it is determined that the obtained ink permeability is not included in the reference permeability range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, in step S40, if the permeability of the obtained ink is higher than the upper limit value of the reference permeability range, as in the permeability Per1 of FIG. 7B, the CPU 41 refers to the graph of FIG. As the permeability of the obtained ink becomes higher than the upper limit value of the standard permeability range, the content of the IR agent included in the ink is set to be smaller than the standard content.

  On the contrary, when the permeability of the obtained ink is lower than the lower limit value of the standard permeability range, as in the permeability Per3 of FIG. 7B, the CPU 41 refers to the graph of FIG. 7B and acquires the ink The content of the IR agent included in the ink is set to be higher than the reference content as the permeability of the ink becomes lower than the lower limit value of the reference permeability range.

  In step S20, it is determined whether or not the acquired ink permeability is included in the reference permeability range, but it is determined whether or not the acquired ink permeability matches the predetermined reference permeability. You may do it. The “reference permeability” is the permeability of a predetermined ink to be compared, and may be set to any value.

  In this case, according to FIG. 7B, the content of the IR agent corresponding to the reference permeability is set as the reference content and stored in the non-volatile memory 44.

  When the permeability of the obtained ink is different from the standard permeability, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph of FIG. 7B, and if the acquired ink permeability is higher than the reference permeability, as the acquired ink permeability becomes higher than the reference permeability, If the content of the IR agent to be included in the ink is set to be lower than the standard content and the permeability of the obtained ink is lower than the standard permeability, the ink may be used as the permeability of the obtained ink becomes lower than the standard permeability. The content of the IR agent to be included is set to be higher than the reference content.

  In the droplet discharge process in which the content of the IR agent is controlled by the permeability of the ink described above, the CPU 41 acquires the permeability of the ink input by the user, for example, but the permeability of the ink is used It is a value determined by the type of paper P.

  For example, the permeability of the ink tends to be lower in the coated paper which has been coated and coated with the coating agent on the surface of the paper P than the most widely used plain paper. In addition, the permeability of the ink tends to be lower in the case of film paper in which a petroleum-derived material such as a seal is used than in coated paper, for example.

  Therefore, for each type of paper P, the type of paper P and the ink penetration rate are stored in advance in the non-volatile memory 44 in association with the type of paper P selected as the paper P to be used by the user. Permeability may be obtained.

<Content Control of IR Agent by Paper Transport Speed>
The image forming attribute also includes the transport speed of the sheet P. Therefore, with reference to FIG. 4, a method of controlling the content of the IR agent when the transport speed of the sheet P is acquired as the image forming attribute in step S10 will be described here.

  FIG. 8 is a diagram showing an example of the change in the content of the IR agent required for the transport speed of the sheet P. As shown in FIG. Specifically, FIG. 8 is required to dry the ink at the transport speed of the sheet P and each transport speed when the same amount of ink is irradiated with the laser beam of maximum intensity from the laser irradiation device 12 It shows an example of the relationship with the content of the IR agent.

  The change example of the content of the IR agent required with respect to the transport speed of the paper P shown in FIG. 8 is an example, and may not necessarily be in a proportional relationship.

  Since the irradiation time of the laser beam irradiated to the ink is shortened as the conveyance speed of the paper P is higher, as shown in FIG. 8, the content of the IR agent contained in the ink is increased as the conveyance speed of the paper P is increased. You need to do more.

  Therefore, in the non-volatile memory 44 of the image forming apparatus 100, the conveyance speed (reference conveyance speed range) of the sheet P, which is the reference predetermined, obtained from the graph of FIG. 8 and IR corresponding to the reference conveyance speed range. The content of the agent is stored. Specifically, a predetermined range including the transport speed Vel2 set as the standard value of the transport speed in the image forming apparatus 100 is set as the reference transport speed range, and the transport speed Vel2 is set to the reference transport speed range. Correspond to the content of IR agent. The graph of FIG. 8 is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the reference transport speed range is an example of the reference content.

  Then, in step S20, the CPU 41 determines whether the conveyance speed of the sheet P acquired in step S10 is included in the reference conveyance speed range. Here, it is assumed that the transport speed of the sheet P is set in advance by the user via the driver screen or the operation panel 18.

  If the obtained conveyance speed of the sheet P is included in the reference conveyance speed range, the process proceeds to step S30, and the content of the IR agent included in the ink is set to the reference content.

  On the other hand, if the determination processing in step S20 is negative, that is, if it is determined that the obtained transport speed of the sheet P is not included in the reference transport speed range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, in step S40, when the acquired conveyance speed of the sheet P is lower than the lower limit value of the reference conveyance speed range as the conveyance speed Vel1 of FIG. 8, the CPU 41 refers to the graph of FIG. As the transport speed becomes lower than the lower limit value of the reference transport speed range, the content of the IR agent included in the ink is set to be smaller than the reference content.

  On the other hand, when the acquired conveyance speed of the sheet P is faster than the upper limit value of the reference conveyance speed range, as in the conveyance speed Vel3 of FIG. 8, the CPU 41 refers to the graph of FIG. The content of the IR agent included in the ink is set to be higher than the reference content as it becomes faster than the upper limit value of the reference conveyance speed range.

  In step S20, it is determined whether the acquired conveyance speed of the sheet P is included in the reference conveyance speed range. However, whether the acquired conveyance speed of the sheet P matches the predetermined reference conveyance speed May be determined. The “reference conveyance speed” is the conveyance speed of the sheet P to be compared, which may be set to any value, but it is about 80 m / min or more, which is called so-called medium speed, and about 100 m. In many cases, the reference transport speed is set in the range of not more than 1 minute.

  In this case, according to FIG. 8, the content of the IR agent corresponding to the reference transport speed is set as the reference content and stored in the non-volatile memory 44.

  If the obtained conveyance speed of the sheet P is different from the reference conveyance speed, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph of FIG. 8 and, when the acquired conveyance speed of the sheet P is slower than the reference conveyance speed, the ink is transported as the acquired conveyance speed of the sheet P becomes slower than the reference conveyance speed. If the content of the IR agent to be included is set smaller than the reference content, and the conveyance speed of the obtained sheet P is faster than the reference conveyance speed, the ink may be transferred as the acquired conveyance speed of the sheet P becomes faster than the reference conveyance speed. The content of the IR agent to be included in is set to be higher than the reference content.

<Control of IR agent content by temperature>
The image formation attribute also includes environmental information around the irradiation position of the sheet P to which the laser light is irradiated. Therefore, with reference to FIG. 9, the control method of the content of the IR agent in the case where the temperature is obtained among the environmental information in step S10 will be described here. Hereinafter, the temperature around the irradiation position of the sheet P to which the laser light is irradiated is simply referred to as “temperature”.

  FIG. 9 is a view showing an example of change in the degree of drying of the ink with respect to the temperature.

  9A shows the relationship between the temperature and the drying energy required to dry the ink when the same amount of ink is irradiated with the laser beam of maximum intensity from the laser irradiation device 12. It is a figure which shows an example.

  Further, FIG. 9 (B) shows the temperature and the drying energy shown in FIG. 9 (A) at each temperature when the laser irradiation device 12 irradiates the same amount of ink with the laser light of the maximum intensity for the same time. It is a figure which shows an example of a relationship with content of IR agent required in order to obtain.

  The lower the temperature, the harder the ink is dried. Therefore, as shown in FIG. 9A, it can be seen that the drying energy required for drying increases as the temperature decreases. Therefore, as shown in FIG. 9B, it is necessary to increase the content of the IR agent included in the ink as the temperature decreases.

  The change in the degree of drying of the ink with respect to the temperature shown in FIG. 9 is an example, and may not necessarily be in a proportional relationship.

  The non-volatile memory 44 of the image forming apparatus 100 contains a reference temperature range (reference temperature range) obtained from the graph of FIG. 9B and an IR agent corresponding to the reference temperature range. The quantity is stored. Specifically, a predetermined range including the temperature Tmp2 set as a standard value of the temperature in the room is set as a reference temperature range, and the content of the IR agent at the temperature Tmp2 is associated with the reference temperature range. The graph of FIG. 9B is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the reference temperature range is an example of the reference content.

  Then, in step S20, the CPU 41 determines whether the temperature measured by the temperature sensor 14 acquired in step S10 is included in the reference temperature range.

  If the acquired temperature is included in the reference temperature range, the process proceeds to step S30, and the content of the IR agent included in the ink is set to the reference content.

  On the other hand, if the determination processing in step S20 is negative, that is, if it is determined that the acquired temperature is not included in the reference temperature range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, in step S40, if the acquired temperature is higher than the upper limit value of the reference temperature range, as in the temperature Tmp1 of FIG. 9B, the CPU 41 refers to the graph of FIG. As the temperature becomes higher than the upper limit value of the temperature range, the content of the IR agent to be contained in the ink is set smaller than the reference content.

  Conversely, when the acquired temperature is lower than the lower limit value of the reference temperature range, as in the temperature Tmp3 of FIG. 9B, the CPU 41 refers to the graph of FIG. 9B and the acquired temperature is within the reference temperature range. As the content becomes lower than the lower limit value, the content of the IR agent included in the ink is set higher than the reference content.

  In step S20, it is determined whether the acquired temperature is included in the reference temperature range, but it may be determined whether the acquired temperature matches the predetermined reference temperature. The “reference temperature” is a predetermined temperature to be compared, and may be set to any value.

  In this case, according to FIG. 9B, the content of the IR agent corresponding to the reference temperature is set as the reference content, and is stored in the non-volatile memory 44.

  If the acquired temperature is different from the reference temperature, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph in FIG. 9B, and if the acquired temperature is higher than the reference temperature, the content of the IR agent included in the ink as the acquired temperature becomes higher than the reference temperature Is set lower than the reference content, and when the acquired temperature is lower than the reference temperature, the content of the IR agent included in the ink is set larger than the reference content as the acquired temperature becomes lower than the reference temperature.

<Control of IR agent content by humidity>
The environmental information includes not only the temperature but also the humidity around the irradiation position of the sheet P to which the laser light is irradiated. Therefore, with reference to FIG. 10, a method of controlling the content of the IR agent in the case where the humidity is acquired as the image forming attribute in step S10 in the environmental information will be described here. Hereinafter, the humidity around the irradiation position of the sheet P to which the laser light is irradiated is simply referred to as “humidity”.

  FIG. 10 is a diagram showing an example of change in the degree of drying of the ink with respect to the humidity.

  10A shows the relationship between the humidity and the drying energy required to dry the ink when the same amount of ink is irradiated with the laser beam of maximum intensity from the laser irradiation device 12. It is a figure which shows an example.

  Further, FIG. 10B shows the humidity and the drying energy shown in FIG. 10A at each humidity when the laser irradiation device 12 irradiates the same amount of ink with the laser beam of maximum intensity for the same time. It is a figure which shows an example of a relationship with content of IR agent required in order to obtain.

  The change in the degree of drying of the ink with respect to the humidity shown in FIG. 10 is an example, and may not necessarily be in a proportional relationship.

  The higher the humidity, the harder the ink is dried. Therefore, as shown in FIG. 10A, it can be seen that the drying energy required for drying increases as the humidity increases. Therefore, as shown in FIG. 10B, it is necessary to increase the content of the IR agent contained in the ink as the humidity increases.

  Therefore, in the non-volatile memory 44 of the image forming apparatus 100, the IR agent corresponding to the reference predetermined humidity range (reference humidity range) obtained from the graph of FIG. 10 (B) and the reference humidity range The content of is stored. Specifically, a predetermined range including the humidity Hum2 set as a standard value of humidity in the room is set as a reference humidity range, and the content of the IR agent in the humidity Hum2 is associated with the reference humidity range. The graph of FIG. 10B is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the reference humidity range is an example of the reference content.

  Then, in step S20, the CPU 41 determines whether the humidity measured by the humidity sensor 16 acquired in step S10 is included in the reference humidity range.

  When the acquired humidity is included in the reference humidity range, the process proceeds to step S30, and the content of the IR agent included in the ink is set to the reference content.

  On the other hand, if the determination processing in step S20 is negative, that is, if it is determined that the acquired humidity is not included in the reference humidity range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, in step S40, if the acquired humidity is lower than the lower limit value of the reference humidity range as in the humidity Hum1 of FIG. 10B, the CPU 41 refers to the graph of FIG. As the temperature falls below the lower limit of the humidity range, the content of the IR agent to be contained in the ink is set to be lower than the reference content.

  On the contrary, when the acquired humidity is higher than the upper limit value of the reference humidity range, as in the humidity Hum3 of FIG. 10B, the CPU 41 refers to the graph of FIG. 10B and the acquired humidity is within the reference humidity range. As the content becomes higher than the upper limit value, the content of the IR agent included in the ink is set to be higher than the reference content.

  In step S20, it is determined whether the acquired humidity is included in the reference humidity range, but it may be determined whether the acquired humidity matches the predetermined reference humidity. The “reference humidity” is a predetermined humidity to be compared, and may be set to any value.

  In this case, according to FIG. 10B, the content of the IR agent corresponding to the reference humidity is set as the reference content, and is stored in the non-volatile memory 44.

  If the acquired humidity is different from the reference humidity, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph in FIG. 10B, and if the acquired humidity is lower than the reference humidity, the content of the IR agent included in the ink as the acquired humidity becomes lower than the reference humidity Is set smaller than the reference content, and when the acquired humidity is higher than the reference humidity, the content of the IR agent included in the ink is set larger than the reference content as the acquired humidity becomes higher than the reference humidity.

  The environmental information includes, in addition to the temperature and humidity described above, information that affects the degree of drying of the ink.

  For example, in the case where a fan that discharges internal heat to the outside is attached to the image forming apparatus 100, a flow of air may occur around the irradiation position of the sheet P to which the laser light is irradiated. When air flow occurs, the faster the wind speed, the easier it is for the ink to dry. Therefore, the wind speed inside the image forming apparatus 100 is measured by a sensor, and the content of the IR agent included in the ink is set smaller as the wind speed becomes faster. You may

  Further, the lower the atmospheric pressure around the irradiation position of the sheet P irradiated with the laser light becomes, the more easily the ink dries. Therefore, the atmospheric pressure inside the image forming apparatus 100 is measured by a sensor, and the IR is included in the ink as the atmospheric pressure decreases. The content of the agent may be set small.

  That is, the wind speed and air pressure of the air flowing inside the image forming apparatus 100 are also examples of the image forming attribute that causes the ink drying degree to change.

<Control of IR agent content by paper thickness>
The image formation attribute also includes the thickness of the sheet P. Therefore, with reference to FIG. 11, a method of controlling the content of the IR agent when the thickness of the sheet P is acquired as the image formation attribute in step S10 will be described here.

The thickness of the sheet P to be used is assumed to be preset by the user and stored in the RAM 43. The thickness of the paper P is also referred to as "paper thickness", and is expressed by the weight (basis weight) of the paper P per 1 m ² . As the paper P having a larger basis weight is thicker, the thickness of the paper P is thicker. Usually, the paper P having a basis weight exceeding 100 g / m ² is often called “thick paper”. It goes without saying that the thickness of the sheet P may be obtained by the length.

  FIG. 11 is a view showing an example of change in the degree of drying of the ink with respect to the thickness of the paper P. As shown in FIG.

  11A shows the thickness of the sheet P and the drying energy required to dry the ink when the same amount of ink is irradiated with the laser beam of the maximum intensity from the laser irradiation device 12 in FIG. It is a figure which shows an example of the relationship of.

  Further, FIG. 11B shows the thickness of the sheet P and the respective thicknesses in FIG. 11A when the laser irradiation device 12 irradiates the laser light of the maximum intensity to the ink for the same time and the same amount. It is a figure which shows an example of a relationship with content of IR agent required in order to obtain drying energy.

  Note that the change in the content of the IR agent contained in the ink with respect to the thickness of the paper P shown in FIG. 11 is an example, and may not necessarily be in a proportional relationship.

  As the thickness of the sheet P decreases, the amount of ink absorbed by the sheet P decreases and the amount of ink remaining on the surface of the sheet P increases. Therefore, as the thickness of the sheet P decreases, as shown in FIG. It can be seen that the drying energy required for drying increases. Therefore, as shown in FIG. 11B, as the thickness of the paper P becomes thinner, it is necessary to increase the content of the IR agent contained in the ink.

  Therefore, in the non-volatile memory 44 of the image forming apparatus 100, the predetermined range of the thickness of the paper P as a reference (reference paper thickness range) and the reference paper thickness range obtained from the graph of FIG. The content of the IR agent corresponding to is stored. Specifically, a predetermined range including the paper thickness Thc2 set as a standard value of the thickness of the paper P is set as a reference paper thickness range, and the IR agent in the paper thickness Thc2 is set to the reference paper thickness range. Correspond to the content. Further, the graph of FIG. 11B is stored in the non-volatile memory 44 of the image forming apparatus 100. The content of the IR agent corresponding to the reference paper thickness range is an example of the reference content.

  Then, in step S20, the CPU 41 determines whether or not the thickness of the sheet P acquired in step S10 is included in the reference sheet thickness range. The thickness of the sheet P is assumed to be set in advance by the user via the driver screen or the operation panel 18.

  If the thickness of the acquired sheet P is included in the reference sheet thickness range, the process proceeds to step S30, and the content of the IR agent to be included in the ink is set to the reference content.

  On the other hand, if the determination in step S20 is negative, that is, if it is determined that the thickness of the acquired sheet P is not included in the reference sheet thickness range, the process proceeds to step S40.

  In this case, if the content of the IR agent contained in the ink is set to the reference content, there is a risk that the drying failure of the ink may occur.

  Therefore, when the thickness of the obtained sheet P is thicker than the upper limit value of the reference sheet thickness range as in the sheet thickness Thc1 of FIG. 11B in step S40, the CPU 41 refers to the graph of FIG. As the thickness of the obtained paper P becomes thicker than the upper limit value of the reference paper thickness range, the content of the IR agent included in the ink is set to be smaller than the reference content.

  On the contrary, when the thickness of the acquired sheet P is thinner than the lower limit value of the reference sheet thickness range as in the sheet thickness Thc3 of FIG. 11B, the CPU 41 refers to the graph of FIG. As the thickness of P becomes thinner than the lower limit value of the reference paper thickness range, the content of the IR agent included in the ink is set to be higher than the reference content.

  In step S20, it is determined whether the thickness of the acquired sheet P is included in the reference sheet thickness range, but it is determined whether the thickness of the acquired sheet P matches the predetermined reference sheet thickness. You may do it. The “reference sheet thickness” is a predetermined sheet thickness to be compared, and may be set to any value.

  In this case, the content of the IR agent corresponding to the reference paper thickness is set as the reference content and stored in the non-volatile memory 44 according to FIG.

  If the thickness of the acquired sheet P is different from the reference sheet thickness, the process proceeds to step S40. Then, in step S40, the CPU 41 refers to the graph of FIG. 11B, and when the thickness of the acquired sheet P is thicker than the reference sheet thickness, as the acquired sheet P becomes thicker than the reference sheet thickness, If the content of the IR agent to be included in the ink is set smaller than the reference content and the thickness of the obtained sheet P is thinner than the reference sheet thickness, the ink is used as the ink as the thickness of the obtained sheet P becomes thinner than the reference sheet thickness. The content of the IR agent to be included is set to be higher than the reference content.

  In the above, the content of the IR agent contained in the ink was controlled focusing on one image formation attribute respectively, but even if the content of the IR agent contained in the ink is controlled by combining a plurality of image formation attributes Good.

<Modified Example 1 of Image Forming Apparatus>
As described above, the image forming apparatus 100 supplies the ink supplied from the ink cartridge 6 to the ink supplied from the ink cartridge 6 from the IR cartridge 8 in order to adjust the content of the IR agent contained in the ink discharged from the ink head 2 according to the image forming attribute. Mix the IR agent to be

  However, the method of mixing the IR agent into the ink is not limited to such a method.

  FIG. 12 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus 100A for forming an image on a sheet P by an inkjet method.

  The configuration of the image forming apparatus 100A shown in FIG. 12 is different from the configuration of the image forming apparatus 100 shown in FIG. 1 in that the ink head driving device 4 is replaced with the ink head driving device 4W and the IR cartridge 8 is removed. In addition, the ink cartridges 6Y, 6M, 6C, and 6K of the respective colors are each divided into three.

Specifically, the ink cartridge 6Y is divided into an ink cartridge 6Y _1, 6Y _2, 6Y _3, the ink cartridge 6M is divided into an ink cartridge 6M _1, 6M _2, 6M _3. The ink cartridge 6C is divided into ink cartridges 6C ₁ , 6C ₂ , 6C ₃ , and the ink cartridge 6K is divided into ink cartridges 6K ₁ , 6K ₂ , 6K ₃ .

  Further, with the division of the ink cartridges 6Y, 6M, 6C, 6K and replacement with the ink head driving device 4W, the droplet discharge device 20 is replaced with the droplet discharge device 20W.

Different amounts of IR agents are mixed in advance in the ink stored in the ink cartridges 6Y ₁ , 6Y ₂ , 6Y ₃ . Similarly, with regard to the ink cartridges 6 of other colors, different amounts of IR agents are mixed in advance in the three ink cartridges 6M _n , 6C _n and 6K _n (n is an integer of 1 to 3). Here, as an example, three ink cartridges 6Y _n , 6M _n , 6C _n , 6K _n having different IR agent contents for each color are prepared, but the respective ink cartridges 6Y _n , 6M _n , 6C _n , The number of 6K _n need not be three, and if there are two or more ink cartridges 6Y _n , 6M _n , 6C _n , and 6K _n having different IR agent contents for each color (ie, n = 2) Good.

In the ink head drive device 4W, control of the control device 10 is performed so that any one ink cartridge 6Y _n , 6M _n , 6C _n , 6K _{n selected} for each ink color is connected to the ink head 2 of each color. The ink supply path is switched according to

The control device 10 of the image forming apparatus 100A controls the ink head driving device 4W so as to approach the content of the IR agent whose drying failure is suppressed, which is obtained from the attribute value of the image formation attribute. One of the ink cartridges 6Y _n , 6M _n , 6C _n , 6K _n is selected. Then, the control device 10 controls the ink head drive device 4W so that the ink is supplied to the ink head 2 of the corresponding color from the selected ink cartridges 6Y _n , 6M _n , 6C _n and 6K _n . Switch the ink supply path prepared for each color.

As described above, by previously providing the ink cartridges 6Y _n , 6M _n , 6C _n , and 6K _n having different IR agent contents for each color, the mechanism for mixing the IR agent into the ink in the ink head driving device 4 becomes unnecessary. .

<Modified Example 2 of Image Forming Apparatus>
In the above-described “Modification 1 of the image forming apparatus”, one of the ink cartridges 6Y _n , 6M _n , 6C _n , and 6K _n is selected for each color to be used, but for the ink of the same color A plurality of ink cartridges 6Y _n , 6M _n , 6C _n , 6K _n may be selected.

  FIG. 13 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus 100B that forms an image on a sheet P by an inkjet method.

  The configuration of the image forming apparatus 100B shown in FIG. 13 differs from the configuration of the image forming apparatus 100A shown in FIG. 12 in that the ink head driving device 4W is replaced with the ink head driving device 4V. Further, the droplet discharge device 20W is replaced with the droplet discharge device 20V along with the replacement with the ink head drive device 4V.

In the ink head driving device 4V, the supply paths for supplying ink from the ink cartridges 6Y _n , 6M _n , 6C _n and 6K _n are respectively directed to the ink heads 2Y, 2M, 2C and 2K of the corresponding colors, It is connected.

The control device 10 of the image forming apparatus 100A controls the ink head driving device 4V to be used so as to approach the content of the IR agent whose drying failure is suppressed, which is obtained from the attribute value of the image forming attribute. And at least one ink cartridge 6Y _n , 6M _n , 6C _n , 6K _n . Then, the control device 10 adjusts the supply amount of ink so that the designated amount of ink is supplied from the selected ink cartridge 6Y _n , 6M _n , 6C _n , 6K _n to the ink head 2 of the corresponding color. Do.

Thus, for example, when the ink cartridge 6Y ₁ and 6Y ₂ in Y color is selected, is mixed by an amount which the ink is specified ink cartridge 6Y ₁ and 6Y _2, it will be ejected from the ink head 2Y to the paper P .

By thus preparing the ink cartridges 6Y _n , 6M _n , 6C _n , and 6K _n having different IR agent contents for each color, and mixing the inks stored in the plurality of ink cartridges 6 for each color, An ink having a content different from the content of the IR agent previously defined for each color ink cartridge 6Y _n , 6M _n , 6C _n , 6K _n is obtained.

<Modification 3 of Image Forming Apparatus>
In the image forming apparatus 100 shown in FIG. 1, the image forming apparatus 100A shown in FIG. 12, and the image forming apparatus 100B shown in FIG. 13, an IR agent is mixed in each color ink of YMCK to correspond to each color. The ink containing the IR agent was discharged onto the sheet P from the ink head 2.

  In this case, for example, when forming a plurality of images having different image coverage on the same sheet P, as described in the flowchart of FIG. 6, if the content of the IR agent contained in the ink is changed for each image having different image coverage. Instead, the content of the IR agent contained in the ink was set according to the maximum image coverage.

  This is because when using an ink mixed with an IR agent, it is difficult to change the content of the IR agent for each image on the same sheet P.

  On the other hand, FIG. 14 shows an example of a schematic configuration showing the main components of the image forming apparatus 100C that changes the content of the IR agent contained in the ink discharged onto the sheet P for each image on the sheet P. FIG.

  The image forming apparatus 100C includes two ink head driving devices 4Q and 4R. Among them, the ink head driving device 4Q supplies ink to the ink head 2 corresponding to each color from the ink cartridges 6Y, 6M, 6C, 6K storing the YMCK inks not containing the IR agent under the control of the control device 10. Then, the designated amount of ink is ejected from the ink head 2. The ink heads 2Y, 2M, 2C, and 2K that discharge the ink not containing the IR agent are an example of the additional discharge unit.

  The ink head driving device 4R mixes the IR agent supplied from the IR cartridge 8 into the transparent color ink supplied from the ink cartridge 6T storing the transparent color ink according to the control of the control device 10, and the IR agent mixes The transparent color ink is ejected from the ink head 2T. The ink head 2T is provided downstream of the position of the ink heads 2Y, 2M, 2C, and 2K in the conveyance direction of the sheet P.

  That is, in the image forming apparatus 100C, as in the image forming apparatuses 100, 100A, and 100B, the IR agent is mixed in the transparent ink and the IR agent is contained instead of mixing the IR agent in the colored ink such as YMCK. The ink heads 2Y, 2M, 2C, and 2K, which discharge ink that is not discharged, and the ink head 2T, which discharges ink containing an IR agent, are separated.

  Therefore, the droplet discharge device 20Q of the image forming apparatus 100C includes the ink head drive devices 4Q and 4R, the ink heads 2Y, 2M, 2C, 2K, and 2T, the ink cartridges 6Y, 6M, 6C, 6K, 6T, and the IR cartridge 8. It is comprised including.

  FIG. 15 is a flowchart showing an example of the flow of the droplet discharge process performed by the CPU 41 of the image forming apparatus 100C.

  The flowchart shown in FIG. 15 is different from the flowchart shown in FIG. 4 in that step S50 is replaced with steps S52 and S54, and the other processes are the same as the process shown in FIG.

  After setting the content of the IR agent to be included in the ink in step S30 or step S40 according to the attribute value of the image formation attribute described above, the CPU 41 executes step S52.

  In step S52, the CPU 41 controls the ink head driving device 4Q to eject ink corresponding to at least one color of YMCK from the ink head 2, and forms an image corresponding to the image data received from the user on the paper P Do.

  In step S54, the CPU 41 controls the ink head driving device 4R to mix the transparent ink and the IR agent so that the content of the IR agent set in step S30 or step S40 is included in the transparent ink. , And an ink of a transparent color mixed with an IR agent is ejected from the ink head 2T.

  In this case, the CPU 41 controls the discharge timing and discharge position of the transparent color ink so that the transparent color ink is superimposed on the image formed on the sheet P in step S52. Therefore, for example, by changing the image coverage of the transparent color ink, the amount of the IR agent to be superimposed on the image formed of the colored ink can be varied for each image.

  The colored ink, such as YMCK, contains a coloring material that is used to develop a specified color, but when the IR agent comes in contact with the coloring material, the stability of the coloring material decreases and color unevenness occurs. There is.

  However, in the image forming apparatus 100C, since the IR agent is mixed in the transparent color ink containing no coloring material, and the transparent color ink is superimposed on the image formed by the colored color ink, the color forming ink is used. The contact between the coloring material and the IR agent is suppressed as compared with the case where the IR agent is directly mixed.

<Modification 4 of Image Forming Apparatus>
In the image forming apparatuses 100, 100A, 100B, and 100C described above, the ink constituting the image formed on the sheet P by the single laser irradiation device 12 is dried, but a plurality of laser irradiation devices 12 are used. The ink may be dried by

  FIG. 16 is a diagram showing an example of a schematic configuration showing main components of an image forming apparatus 100D including a plurality of laser irradiation devices 12. As shown in FIG.

  The image forming apparatus 100D includes four laser irradiation devices 12Y, 12M, 12C, and 12K, and the laser irradiation devices 12Y, 12M, 12C, and 12K have the ink head 2Y, 2M, 2C, and 2K in the conveyance direction downstream of the paper P, respectively. It is installed adjacent to the side.

  When the laser irradiation devices 12Y, 12M, 12C, and 12K are arranged as described above, each of the laser irradiation devices 12Y, 12M, 12C, and 12K sequentially irradiates the laser light to the sheet P conveyed on the conveyance path by the conveyance roll 22. Do. Therefore, the K color ink discharged onto the sheet P is irradiated with laser light from each of the laser irradiation devices 12Y, 12M, 12C, and 12K. The C color ink discharged onto the sheet P is irradiated with laser light from each of the laser irradiation devices 12Y, 12M, and 12C. The M color ink ejected onto the sheet P is irradiated with laser light from each of the laser irradiation devices 12Y and 12M. The Y-color ink discharged onto the sheet P is irradiated with laser light from the laser irradiation device 12Y.

  That is, among the colored inks, the laser light is applied by the plurality of laser irradiation devices 12 to each color ink (the ink of MCK in the example of FIG. 16) other than the ink ejected from the downstream of the transport direction of the sheet P most. As compared with the case where laser light is irradiated from one laser irradiation device 12 as in the image forming apparatus 100 shown in FIG. 1, the irradiation time of the laser light is longer. Therefore, more infrared light is supplied to the ink of each color of MCK as compared with the case where the laser light is irradiated from one laser irradiation device 12, so the image forming apparatus 100 D and the image forming apparatus 100 When forming the same image, the content of the IR agent contained in the ink of each color of MCK in the image forming apparatus 100 D is set smaller than the content of the IR agent contained in the ink of each color of MCK in the image forming apparatus 100 It is also good.

  Further, in the image forming apparatus 100D, when the ink of another color is ejected from the ink head 2 so as to be superimposed on the ink ejected onto the sheet P (the ink of the lower layer), the ink of the lower layer ejects the ink of another color. The ink is dried by a laser irradiation device 12 disposed upstream of the ink head 2 in the transport direction of the sheet P. Therefore, as in the image forming apparatus 100 shown in FIG. 1, color mixing between different colors is suppressed as compared with the case where ink of another color is superimposed without drying the lower layer ink, and the image quality is deteriorated. Will be suppressed.

  Note that the laser irradiation device 12 is disposed downstream of the paper P in the conveyance direction with respect to the ink heads 2Y, 2M, 2C, and 2K in the image forming apparatus 100A shown in FIG. 12 and the image forming apparatus 100B shown in FIG. You may set up adjacently.

  In addition, the laser irradiation device 12 may be disposed adjacent to the downstream side of the sheet P in the conveyance direction with respect to the ink heads 2Y, 2M, 2C, 2K, and 2T in the image forming apparatus 100C illustrated in FIG. In this case, since the IR agent is superimposed on the image formed of the colored ink from the ink head 2T, the content of the IR agent contained in the transparent color ink is set when the image forming apparatus 100 forms the same image. Although the content is the same as the content of the IR agent, deterioration of the image quality is suppressed as compared with the case where the ink ejected onto the sheet P by one laser irradiation device 12 is dried.

  As mentioned above, although this invention was demonstrated using each embodiment, this invention is not limited to the range as described in each embodiment. Various changes or improvements can be added to each embodiment without departing from the scope of the present invention, and a form to which the changes or improvements are added is also included in the technical scope of the present invention. For example, the order of processing may be changed without departing from the scope of the present invention.

  In each embodiment, the IR agent is mixed in the ink by the ink head driving device, but the IR agent is mixed in the ink by the IR agent mixing device, and the ink head is filled with the ink containing the set amount of the IR agent. You may The IR agent mixing apparatus receives information on the content of the IR agent set by the control device of the image forming apparatus, and mixes the IR agent into the ink of each color so as to obtain the received content. The ink containing the IR agent generated by the IR agent mixing device is supplied to the ink head of the corresponding color of the image forming device.

  Also, in each embodiment, an embodiment in which the droplet discharge processing is realized by software has been described as an example, but processing equivalent to the flowcharts shown in FIG. 4, FIG. 6, and FIG. It may be implemented in an integrated circuit and processed by hardware.

  In each of the above-described embodiments, the droplet discharge program is installed in the ROM. However, the present invention is not limited to this. The droplet discharge program according to the present invention can also be provided in the form of being recorded on a computer readable storage medium. For example, the droplet discharge program according to the present invention may be provided in the form of being recorded on an optical disc such as a CD (Compact Disc) -ROM or a DVD (Digital Versatile Disc) -ROM. Further, the droplet discharge program according to the present invention may be provided in the form of being recorded in a semiconductor memory such as a USB (Universal Serial Bus) memory and a flash memory. Furthermore, when the image forming apparatus is connected to a communication line such as the Internet, the droplet discharge program according to the present invention may be obtained from a terminal device such as a server connected to the communication line.

2 (2Y, 2M, 2C, 2K, 2T) ... ink head, 4 (4Q, 4R, 4V, 4W) ... ink head driving device, 6 (6Y, 6M, 6C, 6K, 6T) Ink cartridge 8 IR cartridge 10 Controller 12 (12Y, 12M, 12C, 12K) Laser irradiation device 14 Temperature sensor 16 Humidity sensor 18 ... Operation panel, 20 (20Q, 20V, 20W) ... Droplet discharge device, 22 ... Transport roll, 40 ... Computer, 41 ... CPU, 42 ... ROM, 43 ... RAM 44 non-volatile memory 100 (100A, 100B, 100C, 100D) image forming apparatus

Claims (16)

Discharging means for discharging droplets to a recording medium;
A control unit configured to control the content of the infrared absorbent contained in the droplets discharged from the discharge unit according to an image formation attribute used when forming an image on the recording medium;
Irradiating means for irradiating the recording medium from which droplets have been discharged with infrared light;
Droplet discharge device equipped with The control means acquires, as the image forming attribute, an attribute that causes a change in the degree of dryness of the droplet even when the droplet is irradiated with the infrared light of a predetermined intensity, as the image forming attribute. The droplet discharge device according to claim 1, wherein the content of the infrared absorbent contained in the droplets discharged from the discharge means is controlled in accordance with the above. The control means acquires, as the image forming attribute, the ratio of the area in which the droplet is discharged to the unit area of the recording medium, and the content of the infrared absorber as a reference content as the ratio becomes smaller than the reference ratio The droplet discharge device according to claim 2, wherein the control is performed such that the content of the infrared absorbent is made larger than the reference content as the ratio becomes smaller than the reference ratio. The control means is configured to control the content of the infrared absorbing agent contained in the droplets discharged to each of the plurality of regions when there are a plurality of regions having different proportions in the recording medium. The droplet discharge device according to claim 3, wherein control is performed to set according to the ratio of the region where the ratio is the highest. The droplet discharge device according to claim 3, wherein the control unit performs control of identifying the ratio from the type of an image formed on the recording medium. The control means acquires the permeability of the droplet to the recording medium as the image formation attribute, and the content of the infrared absorber is reduced as compared to the reference content as the permeability of the droplet becomes higher than the reference permeability. The droplet according to any one of claims 2 to 5, wherein control is performed such that the content of the infrared absorbing agent is increased more than the reference content as the permeability of the droplet becomes lower than the reference permeability. Discharge device. The droplet discharge device according to claim 6, wherein the control unit performs control of identifying the permeability of the droplet from the type of the recording medium. The control means acquires the transport speed of the recording medium as the image forming attribute, and reduces the content of the infrared absorber as compared to the reference content as the transport speed of the recording medium becomes slower than the reference transport speed. The droplet discharge according to any one of claims 2 to 7, wherein control is performed such that the content of the infrared absorber is made larger than the reference content as the conveyance speed of the recording medium becomes higher than the reference conveyance speed. apparatus. The control means acquires, as the image forming attribute, the temperature of the portion where the infrared light is irradiated to the recording medium, and the content of the infrared absorbing agent is made higher than the reference content as the temperature becomes higher than the reference temperature. The droplet discharge device according to any one of claims 2 to 8, wherein the control is performed to increase the content of the infrared absorber as the temperature becomes lower than the reference temperature. . The control means acquires, as the image forming attribute, the humidity of the portion where the infrared light is irradiated to the recording medium, and the content of the infrared absorber is made to be a reference content as the humidity becomes lower than the reference humidity. The droplet discharge device according to any one of claims 2 to 9, wherein the control is performed to decrease the content of the infrared absorber as the humidity becomes higher than the reference humidity. . The control means acquires the thickness of the recording medium as the image forming attribute, and as the thickness of the recording medium becomes thicker than a reference value, the content of the infrared absorbing agent is made smaller than the reference content. The droplet discharge device according to any one of claims 2 to 10, wherein control is performed such that the content of the infrared absorbing agent is made larger than the reference content as the thickness becomes thinner than a reference value. The control means is a storage member including a content of the infrared absorber set according to the image formation attribute among a plurality of storage members in which droplets having different contents of the infrared absorber are stored in advance. The droplet discharge device according to any one of claims 1 to 11, which performs control of supplying a droplet to the discharge unit. The control unit performs control of mixing droplets stored in the plurality of storage members and discharging a droplet including the content of the infrared absorbent set according to the image forming attribute from the discharging unit. The droplet discharge device according to Item 12. The droplet discharge device according to any one of claims 1 to 13, wherein the color of the droplet containing the infrared absorbing agent is a transparent color. And an additional discharge unit that discharges a colored droplet not containing the infrared absorber onto the recording medium,
15. The droplet according to claim 14, wherein the control unit controls the discharge unit such that droplets of a transparent color are superimposed and discharged on the colored droplet on the recording medium discharged from the additional discharge unit. Discharge device.   A droplet discharge program for causing a computer to function as a control unit of the droplet discharge device according to any one of claims 1 to 15.