JP7318312B2 - Image forming method, image forming apparatus, and program - Google Patents

Description

The present disclosure relates to controlling the glossiness of a recording medium surface.

2. Description of the Related Art Various techniques have been proposed for controlling the glossiness of the surface of a recording medium on which an image is formed, for conventional image processing apparatuses such as MFPs (Multi-Functional Peripherals). For example, Japanese Patent Laying-Open No. 2015-172685 (Patent Document 1) discloses an image forming apparatus that controls gloss by controlling the surface state of a recording medium using toner for post-processing (clear toner). Japanese Unexamined Patent Application Publication No. 2002-200010 discloses two methods for controlling the gloss level of an image to be printed in this image forming apparatus. The first method is to determine whether the print target is electrophotographic data or offset image data, and determine the adhesion amount of post-processing toner according to the determination result. The second method is to determine the adhesion amount of post-processing toner based on scanned color data when the object to be printed is electrophotographic data, so that unevenness is eliminated in the formed image. .

Japanese Patent Application Laid-Open No. 2015-150708 (Patent Document 2) discloses that, in an inkjet three-dimensional object modeling method, a low-viscosity clear photocurable ink is applied to the surface of a three-dimensional object modeled using a colored photocurable ink. Disclosed is a technique for controlling the glossiness of the surface of a three-dimensional object by discharging.

Republished Japanese Patent No. 2013-157271 (Patent Document 3) is an ink containing a colored photopolymerizable compound, which is an ink that undergoes a sol-gel phase transition. discloses a technique for adjustment using a clear ink having a specific composition.

JP 2015-172685 A JP 2015-150708 A Republished patent No. 2013-157271

However, the conventional technology cannot sufficiently control the viscosity of the ink used for gloss control. For example, in the technique of Patent Document 3, since the viscosity of the clear ink is low, it is sometimes difficult to lower the glossiness by leaving unevenness on the surface of the recording medium. On the other hand, if the viscosity of the clear ink is high, unnatural irregularities may remain on the surface of the recording medium, and the processed recording medium may not provide a natural visual sensation.

The present disclosure has been conceived in view of such circumstances, and its object is to provide a technique for enabling a recording medium whose surface glossiness is controlled to provide a natural visual sensation. be.

According to one aspect of the present disclosure, applying an ink capable of phase transition between sol-gel to a recording medium, and setting a temperature equal to or higher than the phase transition temperature of the ink as a control temperature of the ink applied to the recording medium. A method of forming an image is provided, comprising:

The inking step may comprise applying a clear and colorless ink to the already imaged recording medium.

The image forming method may comprise pressing the ink against the recording medium, and setting a temperature equal to or lower than the phase transition temperature of the ink as a control temperature of the ink in the step of pressing the ink against the recording medium.

The step of pressing the ink against the recording medium may include pressing the ink against the recording medium using a pressing member to which a wax agent is applied. The step of setting a temperature equal to or lower than the phase transition temperature of the ink may include setting a temperature equal to or higher than the melting temperature of the wax agent as the control temperature of the ink.

The image forming method may further comprise applying a wax agent to the pressing member. The step of applying the wax agent may include discharging a dispersion liquid containing the wax agent onto the pressure contact member and volatilizing the dispersion liquid on the pressure contact member.

The image forming method may further comprise the step of setting the amount of wax agent to be applied to the pressing member in accordance with the glossiness targeted for the recording medium.

The step of setting the temperature equal to or higher than the phase transition temperature of the ink may include setting the temperature to control the viscosity of the ink to 100 mPa·s or less. The step of setting the temperature below the phase transition temperature of the ink may include setting the temperature to control the viscosity of the ink in the range of 400 mPa·s to 100000 mPa·s.

The imaging method may further comprise curing the ink.
The ink may contain a material that is cured by irradiation with UV (Ultra Violet) light. Curing the ink may include exposing the ink to UV light.

According to another aspect of the present disclosure, an ink ejection unit that applies ink capable of phase transition between sol-gel to a recording medium, and a control temperature of the ink applied to the recording medium is set to a temperature equal to or higher than the phase transition temperature of the ink. An image forming apparatus is provided, comprising: a computer controlling temperature;

According to still another aspect of the present disclosure, a computer of an image forming apparatus having an ink ejection unit that applies ink capable of phase transition between sol-gel to a recording medium causes the computer to perform A program is provided to cause the step of setting the control temperature of the applied ink to a temperature equal to or greater than the phase transition temperature of the ink.

According to the present disclosure, the state of the ink applied to the recording medium can be brought into a sol state by temperature control. This can smoothen the surface of the ink applied to the recording medium.

1 is a diagram schematically showing the configuration of an image forming apparatus 1; FIG. 2 illustrates an example hardware configuration of an image forming apparatus; FIG. 4A and 4B are diagrams for explaining an example of an image forming process in the image forming apparatus; FIG. 4A and 4B are diagrams for explaining another example of an image forming process in the image forming apparatus; FIG. 4 is a diagram for explaining an example of a temperature range that should be provided by the temperature control unit 150; FIG. FIG. 4 is a diagram for explaining smoothing of an ink surface by heating; 4 is a diagram for explaining an example of a temperature range that should be provided by a temperature control unit 250; FIG. 7A and 7B are diagrams for explaining control of the viscosity of the ink 93 at the nip portion N; FIG. 7A and 7B are diagrams for explaining control of the viscosity of the ink 93 at the nip portion N; FIG. FIG. 7 is a diagram for explaining another example of the range of temperatures that should be provided by the temperature control unit 250; It is a figure which shows an example of the data structure of a glossiness table. 9 is a flow chart of processing for image formation with ink 93 by the ink unit 100. FIG.

An embodiment of an image forming apparatus will be described below with reference to the drawings. In the following description, identical parts and components are given identical reference numerals. Their names and functions are also the same. Therefore, these descriptions will not be repeated.

[1. Schematic Configuration of Image Forming Apparatus]
FIG. 1 is a diagram schematically showing the configuration of an image forming apparatus 1. As shown in FIG. As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 1A and a pressure contact unit 1B.

(Image forming unit 1A)
The image forming unit 1A includes an ink unit 100, a paper path 106 for conveying a recording medium, and a scanner 102. As shown in FIG. The paper feeding path 106 is indicated by a thick line in FIG. is a path containing In FIG. 1 , the paper path 106 is indicated by a thick line, and the recording medium 91 is shown on the paper path 106 . Recording medium 91 is, for example, printing paper. The scanner 102 reads an image formed on the recording medium 91 and generates data of the image.

The ink unit 100 ejects ink for adjusting the glossiness of the recording medium onto the recording medium 91 on the paper path 106 . An ink cartridge containing ink may be attached to the ink unit 100 .

Image forming unit 1A further includes temperature control unit 150 , main roller 191 , rollers 192 , 193 , 194 and 195 , and irradiator 107 . The temperature control unit 150 adjusts the temperature of the recording medium on the paper path 106 and the temperature of the ink on the recording medium by adjusting the temperature in the vicinity of the temperature control unit 150 .

At least one of the main roller 191 and rollers 192 to 195 is driven by a motor (not shown) (part of "various motors 130" described later with reference to FIG. 2) to rotate, The recording medium is conveyed toward the discharge section 1Y. The arrow in each roller in FIG. 1 represents the rotation direction of each roller.

The irradiator 107 irradiates UV (UltraViolet) light. By being irradiated with UV light, the ink ejected from the ink unit 100 is cured on the recording medium.

(Pressure contact unit 1B)
The pressure unit 1B includes a pressure belt 200, an applicator 201, a heater 202, a pressure roller 203, rollers 211 and 212, and a temperature control unit 250. Temperature control unit 250 includes a heating element such as a heater and/or a cooling element such as a fan. The pressure belt 200 is suspended over a pressure roller 203 and rollers 211 and 212 . At least one of pressure roller 203 and rollers 211 and 212 is driven by a motor (not shown) (a part of "various motors 130" to be described later with reference to FIG. 2) to rotate pressure belt 200 in the direction of the arrow. Rotate in the direction indicated by A2.

Applicator 201 contains a wax dispersion and applies the wax dispersion onto pressure belt 200 . A wax dispersion consists of a wax agent dispersed in a given solvent. When the pressure belt 200 rotates in the arrow A2 direction, the heater 202 heats the portion to which the wax dispersion is applied. As a result, the solvent of the wax dispersion applied onto the pressure belt 200 volatilizes, increasing the concentration of the wax agent in the wax dispersion.

As the pressure belt 200 rotates further, the portion of the pressure belt 200 applied with the wax dispersion comes into contact with the recording medium on the paper path 106 . As a result, ink is applied to the recording medium by the ink unit 100, and further wax (contained in the wax dispersion) is applied.

Note that the applicator 201 can apply the wax dispersion as droplets having a diameter smaller than the ink dot diameter (21.2 μm for 1200 dpi). Thereby, the image forming apparatus 1 can control the application amount of the wax dispersion for each ink dot. Therefore, the image forming apparatus 1 can control the amount of wax to be applied to the formed image in units of ink dots. Since the amount of wax agent corresponding to the target glossiness can be applied to each ink dot, gloss unevenness in the entire image can be suppressed.

Wax can be freely applied to any position desired by the user on a recording medium (printing paper, etc.). This allows the user to freely control the gloss for each portion of the recording medium.

The pattern of applying wax can be differentiated between areas with and without dots of ink applied. As a result, it is possible to suppress gloss unevenness due to wax being applied in a similar pattern to both areas where ink dots are applied and areas where ink dots are not applied on the recording medium.

Since gloss control can be performed in units smaller than the ink dot diameter, unevenness on the surface of the image formed on the recording medium can be eliminated to a level that cannot be detected by the human eye. This can ensure image quality.

In this specification, the position where the pressure belt 200 contacts the recording medium on the main roller 191 may be referred to as a "nip portion N." The pressing belt 200 is an example of a pressing member.

The pressing unit 1B includes an element (such as a spring) for urging the pressing belt 200 toward the main roller 191 at the nip portion N. As shown in FIG. Thereby, the pressure belt 200 can be pressed toward the recording medium on the main roller 191 . As the recording medium on the main roller 191 passes through the nip portion N, the wax dispersion applied to the pressure belt 200 moves onto the recording medium.

The temperature control unit 250 adjusts the ambient temperature of the nip portion N. As shown in FIG. Instead of or in addition to the temperature control unit 250, the pressure contact roller 203 may include a temperature control unit for adjusting the temperature of the nip portion N.

(Function configuration for control)
The image forming apparatus 1 further includes an image formation control unit 101, a gloss information input unit 103, a gloss information determination unit 104, and a display control unit 105 as control components. The display control unit 105 displays the image data generated by the scanner 102 on a given display (for example, the “display 112” described later with reference to FIG. 2).

The gloss information determination unit 104 determines the glossiness (target glossiness) that is targeted to be provided on the recording medium. In one implementation example, the glossiness information determining unit 104 extracts information specifying the glossiness from the input job data, and determines the extracted glossiness as the target glossiness. A target glossiness may be determined for each portion of the image formed on the recording medium. The gloss information determination unit 104 identifies an image from the image data generated by the scanner 102, divides the identified image into two or more parts in a given manner, and sets a given condition (for example, described in job data). A target gloss level is determined for each of the two or more portions according to the specified conditions).

The gloss information input unit 103 receives input of information on the target glossiness (value of the target glossiness itself, conditions for determining the target glossiness, etc.). In one implementation, the gloss information input unit 103 obtains a target glossiness value input to a given input device (eg, the “operation button 111” described below with reference to FIG. 2).

The image formation control unit 101 controls ejection of ink from the ink unit 100 according to the target gloss determined by the gloss information determination unit 104 and/or the target gloss based on the information input to the gloss information input unit 103. .

In one implementation, the image formation control unit 101, the gloss information input unit 103, the gloss information determination unit 104, and the display control unit 105 are connected to a given processor (eg, a "CPU (Central Processing Unit) 10A") is implemented by executing a given program. At least one of the image formation control unit 101, the gloss information input unit 103, the gloss information determination unit 104, and the display control unit 105 may be implemented by a dedicated circuit such as an ASIC (Application Specific Integrated Circuit).

[2. Hardware Configuration of Image Forming Apparatus]
FIG. 2 is a diagram illustrating an example of a hardware configuration of an image forming apparatus; Referring to FIG. 2 , image forming apparatus 1 includes a control section 10 that controls the operation of each element in image forming apparatus 1 .

The control unit 10 includes a CPU 10A, a ROM (Read Only Memory) 10B, a RAM (Random Access Memory) 10C, and the like. The CPU 10A reads a program corresponding to the processing content from the ROM 10B, develops it in the RAM 10C, and controls the operation of each block of the image forming apparatus 1 in cooperation with the developed program.

The image forming apparatus 1 includes a storage device 152 . Storage device 152 is implemented by, for example, a hard disk drive. The storage device 152 may store a program executed by the CPU 10A and/or various data (for example, a "glossiness table" to be described later) referred to in executing the program.

Image forming apparatus 1 includes communication interface 151 . The control unit 10 transmits and receives various data to and from an external device (for example, a personal computer) connected to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network) via a communication interface 151. conduct. Communication interface 151 is realized by, for example, a communication control card such as a network card.

Image forming apparatus 1 includes operation buttons 111 and display 112 . The CPU 10A accepts input of information through the operation buttons 111 and displays the execution result of the program on the display 112. FIG. Image forming apparatus 1 may include a touch sensor instead of or in addition to operation button 111 . The touch sensor may constitute a touch panel together with the display 112 .

The ink unit 100 is connected to the control section 10 . The control unit 10 controls ejection of ink by the ink unit 100 .

The image forming apparatus 1 includes various motors 130 . The control unit 10 controls the operation of each motor included in the various motors 130 .

Image forming apparatus 1 includes temperature sensor group 120 . Temperature sensor group 120 includes one or more temperature sensors that measure temperatures of one or more portions (eg, nip portion N) in image forming apparatus 1 . The CPU 10A acquires measured temperature information from each of the one or more temperature sensors.

The CPU 10A further controls the operations of the temperature control unit 150, the temperature control unit 250, the applicator 201, the heater 202, and the irradiator 107 respectively.

[3. Flow of Image Formation (Formation of Image with Low Glossiness)]
FIG. 3 is a diagram for explaining an example of an image forming process in the image forming apparatus 1. As shown in FIG. In FIG. 3, four stages are shown as (a) to (d).

(First step: (a) in FIG. 3)
In the first stage, an applicator 201 applies a wax dispersion onto a pressure belt 200, as shown in FIG. 3(a). In FIG. 3, the droplets of wax dispersion are shown as wax dispersion 94 .

In one implementation, the applicator 201 dispenses a wax dispersion toward the pressure belt 200 in an amount that corresponds to a target gloss level set for the image to be formed. The portion of the pressure belt 200 to which the wax dispersion 94 is applied moves to the vicinity of the heater 202 as it rotates in the direction of arrow A2 in FIG.

(Second stage: (b) in FIG. 3)
In the second step, the wax dispersion 94 on the pressure belt 200 is heated by the heater 202, as shown in FIG. 3(b). Heating causes the solution portion of the wax dispersion 94 to evaporate on the pressure belt 200, and the concentration of the wax agent can be increased. The portion of the pressure belt 200 to which the wax agent (wax dispersion liquid 94) is applied moves to the nip portion N by rotating in the direction of arrow A2 in FIG.

(Third step: (c) in FIG. 3)
In the third stage, as shown in FIG. 3C, the surface of the pressure belt 200 to which the wax agent (wax dispersion liquid 94) is applied contacts the surface of the recording medium 91 to which the ink is applied. In (c) of FIG. 3 , the wax agent (wax dispersion 94 ) is shown below the pressure belt 200 in consideration of the rotation of the pressure belt 200 . In one implementation, the condition of FIG. 3(c) occurs at the nip N.

In FIG. 3 , the ink ejected from the ink unit 100 is shown as ink 93 . The ink 92 represents the ink that forms the image formed on the recording medium 91 before the recording medium 91 reaches the ink unit 100 . That is, the image forming apparatus 1 forms an image for gloss control on the recording medium 91 on which an image has already been formed. In one implementation, the inking unit 100 ejects a clear, colorless ink for gloss control.

(Fourth stage: (d) in FIG. 3)
In the fourth stage, the surface of the pressure belt 200 separates from the surface of the recording medium by further rotating the pressure belt 200, as shown in FIG. 3(d). Part of the surface of the ink 93 on the recording medium 91 is not covered with the wax agent (wax dispersion liquid 94). As a result, as shown in (d) of FIG. 3, unevenness may occur on the surface of the ink after separation. Therefore, the glossiness of the image formed on the recording medium can be relatively low.

[4. Flow of Image Formation (Formation of Image with Low Glossiness)]
FIG. 4 is a diagram for explaining another example of the image forming process in the image forming apparatus 1. As shown in FIG. In FIG. 4, as in FIG. 3, four stages are indicated by (a) to (d).

As shown in (a) to (c) of FIG. 4, in the example of FIG. 4, similarly to the example of FIG. 94 is heated by a heater 202 and then the pressure belt 200 contacts the recording medium 91 . In one implementation, the condition of FIG. 4(c) occurs at nip N. FIG.

In the example of FIG. 4, the amount of the wax dispersion liquid 94 applied onto the pressure belt 200 is relatively large, and almost the entire surface of the ink 93 on the recording medium 91 is covered with the wax agent. As a result, as shown in FIG. 4(d), the surface of the ink after separation is smooth. Therefore, in the example of FIG. 4, the glossiness of the image formed on the recording medium 91 can be relatively high.

[5. Ink temperature control up to press contact]
FIG. 5 is a diagram for explaining an example of the temperature range that should be provided by the temperature control unit 150. As shown in FIG. A graph is shown in FIG. In the graph, the vertical axis represents ink viscosity, and the horizontal axis represents temperature. A line L1 represents the change in the viscosity of the ink ejected by the ink unit 100 with temperature.

In the image forming apparatus 1 , the ink ejected by the ink unit 100 is heated to a phase transition temperature or higher before the recording medium 91 contacts the pressure belt 200 at the nip portion N. More specifically, after the ink unit 100 ejects ink, the CPU 10A causes the temperature control unit 150 to heat the ink to the phase transition temperature or higher. As a result, the ink ejected by the ink unit 100 becomes a sol, and the surface of the ink is smoothed. "Smoothing" is also referred to herein as "leveling."

The temperature control unit 150 may heat the ink within a temperature range that ensures that the ink becomes a sol. In FIG. 5, the temperature range in which it is confirmed in advance that the ink is surely converted into a sol is shown as temperatures T1 to T2. The temperature T1 is equal to or higher than the phase transition temperature of ink. In one implementation, the temperature control unit 150 heats the ink 93 on the recording medium 91 so that the viscosity of the ink 93 is 100 mPa·s or less.

FIG. 6 is a diagram for explaining the smoothing of the ink surface by heating. FIG. 6 shows three states ST11, ST12 and ST13.

State ST11 represents the state of the surface of the recording medium 91 before the ink unit 100 ejects ink. State ST12 represents a state in which the surface of the ink 93 is smoothed by heating after the ink unit 100 ejects the ink 93 . A state ST13 represents a state after the ink unit 100 ejects the ink 93 and before the surface is smoothed by heating.

In state ST11, an image is formed on the recording medium 91 with the ink 92. FIG. For example, if the image formed by the ink 92 is a halftone image, the intervals between dots formed by the ink 92 are relatively large. Therefore, in such a case, conspicuous irregularities may occur on the recording medium 91, as shown as state ST11.

In the state ST12, the surface of the ink 93 is smoothed so that when the recording medium 91 contacts the pressure belt 200 ((c) of FIG. 3 and (c) of FIG. 4), the surface of the ink 93 is smoothed. It contacts the pressure belt 200 as a whole. On the other hand, in state ST13, since the surface of the ink 93 has unevenness, when the recording medium 91 comes into contact with the pressure belt 200, a part of the surface of the ink 93 may not come into contact with the pressure belt 200. .

If the surface of the ink 93 cannot contact the pressure belt 200 , the corresponding portion cannot contact the wax agent (wax dispersion liquid 94 ) applied on the pressure belt 200 . Therefore, depending on the contact with the pressure belt 200, there is a possibility that the glossiness of the surface of the ink 93 cannot be sufficiently controlled.

In other words, by smoothing the surface of the ink 93 before contact with the pressure belt 200 as shown in the state ST12, the glossiness of the surface of the ink 93 (that is, the recording The glossiness of the media 91 surface can be controlled. As a result, it is possible to avoid unnatural irregularities remaining on the surface of the recording medium 91 output from the image forming apparatus 1, and to provide a natural visual sensation.

[6. Ink temperature control at nip portion N]
FIG. 7 is a diagram for explaining an example of the temperature range that should be provided by the temperature control unit 250. As shown in FIG. In FIG. 7, similarly to FIG. 5, the temperature change of the viscosity of the ink ejected by the ink unit 100 is indicated by the line L1.

In the image forming apparatus 1, it is possible to prevent the viscosity of the ink 93 ejected by the ink unit 100 from decreasing more than necessary at the nip portion N. As a result, it is possible to avoid insufficient control of the glossiness of the surface of the recording medium 91 due to an excessive decrease in the viscosity of the ink 93 .

8 and 9 are diagrams for explaining control of the viscosity of the ink 93 at the nip portion N. FIG. FIG. 8 shows four states ST21, ST22, ST23 and ST24.

State ST21 represents a state immediately before the pressure belt 200 and the recording medium 91 come into contact with each other at the nip portion N. FIG. State ST22 represents a state in which the pressure belt 200 and the recording medium 91 are in contact with each other at the nip portion N. FIG.

State ST23 and state ST24 each represent a state when pressure belt 200 is separated from recording medium 91 after state ST22. In state ST23, the viscosity of ink 93 is sufficiently high. Therefore, when the recording medium 91 to which the ink 93 is applied is peeled off from the pressure belt 200, the "hump" formed on the surface of the ink 93 is maintained. Thereby, the surface of the ink 93 can sufficiently reduce the glossiness of the surface of the recording medium 91 .

On the other hand, in state ST24, the viscosity of the ink 93 is too low to maintain the above-mentioned "peak". Therefore, the "hump" generated when the recording medium 91 is peeled off from the pressure belt 200 can shrink or disappear before the recording medium 91 reaches the position where the UV light is irradiated from the irradiator 107 . As a result, the surface of the ink 93 may not sufficiently reduce the glossiness of the surface of the recording medium 91 .

As described above, the CPU 10A controls the viscosity of the ink 93 at the nip portion N to be sufficiently high. An example viscosity range is from 400 mPa·s to 100000 mPa·s. Regarding this point, for example, when using ink having a viscosity of about 20 to 30 mPa·s at the time when the pressure contact at the nip portion N is eliminated, transfer failure occurs, and the image is disturbed after passing through the nip portion N. can occur. It is presumed that such image disturbance is due to the absence of gel transition.

In one implementation, the CPU 10A sets the set temperature of the temperature control unit 250 so that the temperature of the ink 93 is below the phase transition temperature in order to increase the viscosity of the ink 93 .

The temperature control unit 250 may heat the ink 93 within a temperature range that reliably gels the ink. In FIG. 7, the temperature range in which it has been confirmed in advance that the ink surely gels is shown as temperatures T3 to T4. The temperature T4 is below the phase transition temperature of the ink.

Referring to FIG. 9, pressure contact will be described when ink 93 is not leveled (smoothed) before pressure contact. State ST25 and state ST26 are shown in FIG. State ST25 shows the surface of recording medium 91 when ink 93 is not leveled. State ST26 shows the surface of the recording medium 91 when pressure contact is performed in the state shown in state ST25. As shown in state ST26, if leveling is not performed before pressure contact, unevenness of the original image formed by the ink 92 remains even after pressure contact, which does not provide a natural visual sensation.

FIG. 10 is a diagram for explaining another example of the temperature range that should be provided by the temperature control unit 250. In FIG. At the nip portion N, it is preferable that the wax agent of the wax dispersion liquid 94 is sufficiently melted. Therefore, the CPU 10A may cause the temperature control unit 250 to raise the temperature of the ink 93 at the nip portion N to the melting point of the wax agent or higher. In one implementation, the temperature range over which the wax agent is reliably melted is narrower than the temperature range over which the ink 93 is reliably gelled. FIG. 10 shows an example of a temperature range in which the wax agent is reliably melted as temperatures T5 to T4. More specifically, FIG. 10 includes a line L2 representing the change in clay with respect to the temperature of the wax agent. Temperature T5 represents the melting point (melting temperature) of the wax agent. That is, control within the temperature range T5 to T4 corresponds to control above the melting point of the wax agent.

[7. Application amount of wax dispersion]
FIG. 11 is a diagram showing an example of the data structure of the "gloss level table". FIG. 11 shows "amount of wax dispersion applied to one dot area" corresponding to the target glossiness. A 1-dot area represents an area of one dot forming an image formed by the ink 92 on the recording medium 91 .

In FIG. 11, “X” represents the droplet size (eg, droplet diameter) applied by applicator 201 . The applicator 201 can apply to the recording medium 91 droplets that are smaller in size than the dots forming the image formed by the ink 92 . Thereby, in the image forming apparatus 1 , the glossiness can be controlled for each dot of the image formed with the ink 92 .

In the example of FIG. 11, each target glossiness value is applied to an area of the pressure belt 200 corresponding to one dot area (an area corresponding to one dot forming an image formed by the ink 92). The amount of wax dispersion to be applied is defined.

For example, "X" is set for the target glossiness of "9". This means that when the target glossiness value is "9", the applicator 201 applies one drop of the wax dispersion to the area corresponding to the one-dot area of the pressure belt 200 .

“4X” is set for the target glossiness of “54”. This means that when the target glossiness value is "54", the applicator 201 applies 4 drops of the wax dispersion to the area corresponding to the 1-dot area of the pressure belt 200 .

That is, the higher the target glossiness value, the greater the amount of the wax dispersion applied from the applicator 201 per unit area.

[8. Process flow]
FIG. 12 is a flow chart of processing for image formation with ink 93 by the ink unit 100 . The ink 93 may be colorless and transparent ink. In this case, a colorless image for gloss adjustment is formed with the ink 93 by the processing of FIG.

The process of FIG. 12 is started, for example, when the image forming apparatus 1 is instructed to start a job. In one implementation, the process of FIG. 12 is implemented by CPU 10A executing a given program. Note that the processing of FIG. 12 may be realized by one or more dedicated circuits such as ASIC.

In step S10, CPU 10A sets the temperature of temperature control unit 150. FIG. In one implementation, at step S10, the CPU 10A sets the temperature at which the temperature control unit 150 turns on/off. This temperature is a temperature for adjusting the temperature of the ink 93 to be equal to or higher than the phase transition temperature of the ink 93 or within the range of temperatures T1 to T2 in FIG. That is, the control in step S10 corresponds to a step of setting a temperature equal to or higher than the phase transition temperature of the ink as the control temperature of the ink applied to the recording medium.

In step S<b>12 , CPU 10</b>A sets the temperature of temperature control unit 250 . In one implementation, at step S12, the CPU 10A sets the temperature at which the operation of the temperature control unit 250 is switched on/off. This temperature is a temperature for adjusting the temperature of the ink 93 to be below the phase transition temperature of the ink 93, within the range of temperatures T3 to T4 in FIG. 7, or within the range of temperatures T5 to T4 in FIG. That is, the control in step S12 corresponds to the step of setting the ink control temperature in the nip portion N to a temperature equal to or lower than the phase transition temperature of the ink.

At step S14, CPU 10A reads the image read by scanner 102. FIG. In step S14, the image formed by the ink 92 on the recording medium 91 may be read. The CPU 10A may acquire data of the image from an external device.

In step S16, the CPU 10A sets an area on the recording medium 91 to which the ink 93 should be applied. In one implementation, the CPU 10A sets only the image-formed area (the area to which the ink 92 is applied) on the recording medium 91 as the area to which the ink 93 is to be applied.

At step S18, the CPU 10A reads out the target glossiness. The target glossiness may be included in the job data, or may be input to the image forming apparatus 1 via the glossiness information input unit 103 . Also, the CPU 10A can acquire the target glossiness by any other method.

The CPU 10A may determine the target glossiness of each portion of the image on the recording medium 91 based on the image data generated by the scanner 102 (or obtained from an external device).

Specific examples of the method for determining the target glossiness are described, for example, as Examples 1 to 4 below. The CPU 10A applies the toner 93 onto the recording medium 91 using the ink unit 100 so as to achieve the determined target glossiness of each portion.

Example 1: The CPU 10A calculates luminance information (for example, L* value) from image data (RGB data) and sets a gloss value proportional to the luminance value. The constant of proportionality is, for example, set in the image forming apparatus 1 in advance by the user.

Example 2: The CPU 10A discriminates the type of image (photograph, picture, text, etc.) of each part formed on the recording medium 91, and the photo part/picture part becomes high gloss, and the text part becomes low gloss. As such, the ink 93 is applied. For example, the glossiness corresponding to each of high glossiness and low glossiness is set in the image forming apparatus 1 in advance by the user.

Example 3: The CPU 10A learns the image pattern and the optimum glossiness for it by machine learning such as AI (Artificial Intelligence), and uses the model generated by the learning to determine each part formed on the recording medium 91. image type, and set an appropriate gloss level for each part.

Example 4: The image forming apparatus 1 has a monitor that displays an image formed on the recording medium 91 . While viewing the image displayed on the monitor, the user sets the glossiness of each part of the image forming apparatus 1 .

In step S20, the CPU 10A refers to the glossiness table (FIG. 11) to apply the application amount corresponding to the target glossiness value read (acquired) in step S18. It is set as the amount of wax dispersion applied per area.

In step S22, CPU 10A forms an image with ink 93 on recording medium 91 according to the settings in steps S10 to S20. The image of the ink 93 formed on the recording medium 91 is cured by UV light emitted from the irradiator 107 . After that, the recording medium 91 is ejected from the image forming apparatus 1 via the ejection section 1Y.

[9. summary]
In the embodiment described above, the image forming apparatus 1 applies ink to the recording medium by an inkjet method, but the method for applying ink is not limited to this. The ink may also be applied to the recording medium by other methods, such as gravure or screen.

Further, instead of controlling the temperature of the ink after being applied onto the recording medium by the temperature control unit 150, the temperature of the ink before being ejected from the ink unit 100 may be controlled. Any stage of the temperature may be adjusted as long as the surface of the ink is smoothed on the recording medium as described with reference to FIG. 6 and the like.

Each embodiment disclosed this time should be considered as an illustration and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. In addition, the inventions described in the embodiments and modifications are intended to be implemented either singly or in combination as much as possible.

Reference Signs List 1 image forming apparatus 1A image forming unit 1B pressure contact unit 1X introduction unit 1Y discharge unit 10 control unit 10A CPU 91 recording medium 92, 93 ink 94 wax dispersion 100 ink unit 101 image formation Control unit 102 Scanner 103 Gloss information input unit 104 Gloss information determination unit 105 Display control unit 106 Paper path 107 Irradiator 111 Operation button 112 Display 120 Temperature sensor group 130 Various motors 150, 250 temperature control unit, 151 communication interface, 152 storage device, 191 main roller, 192, 193, 194, 195, 211, 212 roller, 200 pressure belt, 201 applicator, 202 heater, 203 pressure roller.

Claims (11)

applying an ink capable of phase transition between sol-gel to a recording medium;
setting a temperature equal to or higher than the phase transition temperature of the ink as a control temperature of the ink applied to the recording medium;
pressing the ink against a recording medium;
setting a temperature equal to or lower than the phase transition temperature of the ink as the control temperature of the ink in the step of pressing the ink against the recording medium;
The step of pressing the ink against the recording medium includes pressing the ink against the recording medium using a pressing member to which a wax agent is applied,
The step of setting a temperature equal to or lower than the phase transition temperature of the ink includes setting a temperature equal to or higher than the melting temperature of the wax agent as the control temperature of the ink,
An image forming method , further comprising the step of applying the wax agent to the member for pressure contact . 2. The step of applying the wax agent according to claim 1 , wherein the step of applying the wax agent includes discharging a dispersion liquid containing the wax agent onto the pressure contact member, and volatilizing the dispersion liquid on the pressure contact member. image forming method. 3. The image forming method according to claim 1 , further comprising the step of setting the amount of said wax agent to be applied to said pressing member according to a desired glossiness of a recording medium . The step of setting a temperature equal to or higher than the phase transition temperature of the ink includes setting a temperature for controlling the viscosity of the ink to 100 mPa s or less,
The step of setting the temperature below the phase transition temperature of the ink includes setting the temperature for controlling the viscosity of the ink within a range from 400 mPa·s to 100000 mPa·s . The image forming method according to any one of . 5. The image forming method according to any one of claims 1 to 4, wherein the step of applying ink includes applying colorless and transparent ink to a recording medium on which an image has already been formed. The image forming method according to any one of claims 1 to 5 , further comprising a step of curing said ink. The ink contains a material that cures when irradiated with UV (Ultra Violet) light,
7. The image forming method of claim 6 , wherein curing the ink includes irradiating the ink with UV light. an ink ejection unit that applies ink capable of phase transition between sol-gel to a recording medium;
a computer that controls the control temperature of the ink applied to the recording medium to a temperature equal to or higher than the phase transition temperature of the ink ;
The computer is
pressing the ink against a recording medium;
setting a temperature equal to or lower than the phase transition temperature of the ink as a control temperature of the ink in the step of pressing the ink against the recording medium;
Applying a wax agent to the pressure contact member,
pressing the ink against the recording medium includes pressing the ink against the recording medium using the pressing member to which the wax agent is applied;
The image forming apparatus , wherein setting a temperature equal to or lower than the phase transition temperature of the ink includes setting a temperature equal to or higher than the melting temperature of the wax agent as the control temperature of the ink. The step of applying the wax agent to the pressure contact member includes discharging a dispersion liquid containing the wax agent to the pressure contact member, and volatilizing the dispersion liquid on the pressure contact member. Item 9. The image forming apparatus according to item 8. By being executed by a computer of an image forming apparatus having an ink ejection unit that applies ink capable of phase transition between sol-gel to a recording medium, the computer,
setting the control temperature of the ink applied to the recording medium to a temperature equal to or higher than the phase transition temperature of the ink ;
pressing the ink against a recording medium;
setting a temperature equal to or lower than the phase transition temperature of the ink as the control temperature of the ink in the step of pressing the ink against the recording medium;
The step of pressing the ink against the recording medium includes pressing the ink against the recording medium using a pressing member to which a wax agent is applied,
The step of setting a temperature equal to or lower than the phase transition temperature of the ink includes setting a temperature equal to or higher than the melting temperature of the wax agent as the control temperature of the ink,
A program for causing the computer to further execute a step of applying the wax agent to the pressure contact member . 11. The step of applying the wax agent according to claim 10, wherein the step of applying the wax agent includes discharging a dispersion liquid containing the wax agent onto the pressure contact member and volatilizing the dispersion liquid on the pressure contact member. program.

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