JP7516882B2 - IMAGE FORMING METHOD, IMAGE FORMING PROGRAM, AND IMAGE FORMING APPARATUS - Google Patents

Description

The present invention relates to an image forming method, an image forming program, and an image forming device.

An electrophotographic image forming apparatus typically has four photosensitive drum units. Such an image forming apparatus is called a four-cylinder machine. A four-cylinder machine typically uses four colors of toner: yellow (Y (Yellow)), magenta (M (Magenta)), cyan (C (Cyan)), and black (K (Key plate)). In this specification, when there is no need to distinguish between these toners, they are referred to as YMCK toners.

In recent years, electrophotographic image forming devices may use color toners other than YMCK toners. In this specification, color toners other than YMCK toners are referred to as special color toners.

When using special color toner, a cylinder is added to the four cylinders to make a five-cylinder machine, or two cylinders are added to make a six-cylinder machine, and a toner image is formed using an additional photosensitive drum unit.

In some 5-cylinder or 6-cylinder image forming devices, when special color toners are used, the special color toner is transferred to the image forming medium along with the YMCK toners during the secondary transfer and fixed at the same time.

In print shops and printing companies, it is preferable to be able to use a variety of special color toners in response to user requests. However, the charging characteristics and thermal properties of the wide variety of special color toners differ from those of YMCK toners.

The charging characteristics and thermal properties of each of the YMCK toners are similar, so images can be formed and fixed under a single set of image forming conditions.

However, the image forming conditions for spot color toners may differ from those for YMCK toners. For this reason, in order to use a wide variety of spot color toners, it is necessary to set image forming conditions suitable for each spot color toner. Moreover, it is difficult to determine image forming conditions that can form a good image using YMCK toners and spot color toners simultaneously from prior information such as the charging characteristics and thermal properties of the toners.

Conventional methods for determining image formation conditions suitable for the toner used include, for example, a technique for optimizing the development bias for developing a toner latent image transferred to the surface of a latent image carrier (photoconductor drum) (Patent Document 1). Another conventional technique is a technique for optimizing the energy density of a light beam for forming a latent image on a latent image carrier together with the development bias (Patent Document 2).

JP 2003-295531 A JP 2007-140545 A

However, all of the conventional techniques focus on optimizing the conditions for exposure and development on the latent image carrier, and do not take into account the fixing conditions.

On the other hand, in order to use YMCK toner and special color toners simultaneously, it is also necessary to optimize the fixing conditions. In particular, in recent years, the trend toward low-temperature fixing of YMCK toners has been coupled with market needs to use a variety of special color toners, and there is a demand for technology that allows YMCK toner and special color toners to be used simultaneously under optimal fixing conditions.

The object of the present invention is to provide an image forming method, an image forming program, and an image forming device that can determine and set image forming conditions suitable for two or more types of toner.

The above object of the present invention is achieved by the following means:

(1) An image forming method in which an image is formed on an image forming medium using a first toner and a second toner and then fixed,
(a) fixing an image formed by the second toner on the image forming medium at a fixing temperature within a preset appropriate fixing temperature range of the first toner;
a step (b) of determining whether the gloss of the image fixed by the step (a) is within a predetermined gloss range;
(c) setting the fixing temperature used in the step (a) as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium when the determination result of the step (b) is within the predetermined gloss range; and
The image forming method according to claim 1,

(2) when the result of the determination in the step (b) is less than the lower limit of the predetermined glossiness, a step (a1) of fixing an image newly formed with the second toner on the image forming medium at a fixing temperature which is increased by a preset temperature from the fixing temperature in the step (a);
After the step (a1), a determination is made according to the step (b), and if the determination result is within the range of the predetermined glossiness, the fixing temperature used in the step (a1) is set as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium.
The image forming method described in (1) above, wherein if the judgment result of step (b) is not within the predetermined gloss range, step (a1) and step (b) are repeated until the gloss range is reached.

(3) The image forming method according to (2) above, further comprising a step (d1) of outputting a warning if the result of the determination in step (b) is less than the lower limit of the predetermined glossiness after repeating step (a1) and step (b) until the fixing temperature reaches a predetermined upper limit temperature.

(4) a step (a2) of fixing an image formed by the second toner on the image forming medium at a fixing temperature lowered by a preset temperature from the fixing temperature in the step (a) when the result of the determination in the step (b) exceeds the upper limit of the predetermined gloss level,
After the step (a2), a step (c2) is performed to determine whether the gloss level is within the predetermined range. If the result of the determination is within the predetermined range, the fixing temperature used in the step (a1) is set as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium.
The image forming method described in (1) above, wherein if the judgment result of step (b) is not within the predetermined gloss range, step (a2) and step (b) are repeated until the gloss range is reached.

(5) The image forming method according to (4) above, further comprising a step (d2) of outputting a warning when the result of the determination in step (b) exceeds the upper limit of the predetermined glossiness as a result of repeating steps (a2) and (b) until the fixing temperature reaches a predetermined lower limit temperature.

(6) The predetermined gloss range is defined as a range of predetermined gloss values measured by a gloss meter,
The image forming method according to any one of (1) to (5), wherein in the step (b), the image fixed on the image forming medium is measured with the gloss meter and compared with the range of gloss values to determine the gloss value.

(7) the first toner is at least one of yellow, magenta, cyan, and black toner;
The image forming method according to any one of (1) to (6) above, wherein the second toner is a special color toner.

(8) The image forming method described in (7) above, in which the special color toner is a white toner.

(9) An image forming program for causing a computer to execute the image forming method described in any one of (1) to (8) above.

(10) a toner image forming unit that forms an image on an image forming medium using the first toner and the second toner;
a fixing section for fixing the image formed by the toner onto the image forming medium;
a storage unit that stores a fixing temperature of the fixing unit;
a control unit that sets the fixing temperature in the fixing unit to a fixing temperature within an appropriate fixing temperature range for the first toner, fixes an image formed with the second toner onto the image forming medium, determines whether or not the gloss of the fixed image is within a predetermined gloss level range, and, if the determination result is within the predetermined gloss level range, stores the fixing temperature set in the fixing unit in the storage unit as the fixing temperature when an image is formed with the first toner and the second toner and fixed onto the image forming medium;
An image forming apparatus comprising:

(11) When the determination result is less than the lower limit of the predetermined gloss level, the control unit resets the fixing temperature of the fixing unit to a fixing temperature that is increased by a preset temperature from the fixing temperature set in the fixing unit, and fixes a new image formed with the second toner onto the image forming medium.
The image forming apparatus described in (10) above determines whether the gloss of an image fixed at the reset fixing temperature is within the specified gloss range, and if the result of the determination is within the specified gloss range, stores the reset fixing temperature in a memory unit as the fixing temperature when forming an image using the first toner and the second toner and fixing it to the image forming medium.

(12) The image forming device according to (11) above, in which the control unit repeats resetting of the fixing temperature and fixing of the image using the second toner until the fixing temperature reaches a predetermined upper limit temperature, and outputs a warning when the judgment result is below the lower limit of the predetermined glossiness.

(13) When the determination result exceeds the upper limit of the predetermined gloss level, the control unit resets the fixing temperature of the fixing unit to a fixing temperature lowered by a preset temperature from the fixing temperature set in the fixing unit, and fixes a new image formed with the second toner onto the image forming medium.
The image forming apparatus described in (10) above, which determines whether the gloss of an image fixed at the reset fixing temperature is within the specified gloss range, and if the result of the determination is within the specified gloss range, stores the reset fixing temperature in the memory unit as the fixing temperature when forming an image using the first toner and the second toner and fixing it to the image forming medium.

(14) The image forming device described in (13) above, in which the control unit repeats resetting the fixing temperature and the image fixing operation using the second toner until the fixing temperature reaches a predetermined lower limit temperature, and outputs a warning if the result of the judgment after resetting exceeds the upper limit of the predetermined gloss level.

(15) A gloss meter is provided downstream of the fixing unit in a conveying direction of the image-forming medium, the gloss meter measuring the gloss of the image-forming medium.
the predetermined gloss range stored in the memory unit is defined as a predetermined gloss value range measured by the gloss meter,
The control unit compares the gloss value of the image formed with the second toner obtained by measuring the image forming medium with the gloss meter with the predetermined gloss value range, and determines whether the gloss value of the image formed with the second toner is within the predetermined gloss value range.

(16) The first toner is at least one of yellow, magenta, cyan, and black toner;
The image forming apparatus according to any one of (11) to (15) above, wherein the second toner is a special color toner.

(17) The image forming device according to (16) above, in which the special color toner is white toner.

In the present invention, an image formed with the second toner is fixed within the appropriate fixing temperature range of the first toner, and if the gloss of the second toner is good, the fixing temperature at that time is set as the fixing temperature at which the first toner and the second toner can be used simultaneously. This makes it possible to determine and set image formation conditions suitable for two or more types of toner.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram showing a control system of the image forming apparatus according to the embodiment. 11 is a flowchart showing a processing procedure for optimizing fixing conditions in order to simultaneously use YMCK toners and special color toners. 4 is a flowchart showing the processing procedure following FIG. 3. 4 is a flowchart showing the processing procedure following FIG. 3. 4 is a flowchart showing the processing procedure following FIG. 3.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. Note that in the description of the drawings, the same elements are given the same reference numerals, and duplicate descriptions will be omitted. Also, the dimensional ratios in the drawings have been exaggerated for the convenience of explanation, and may differ from the actual ratios.

Figure 1 is a schematic diagram showing the configuration of an image forming apparatus according to one embodiment.

The image forming device 1 has a paper feed unit 100, an image forming unit 120, and a reading unit 140.

The paper feed unit 100 stores paper, which is the image formation medium. The paper feed unit 100 supplies the paper to a transport path 101 that transports the paper within the image forming device 1. The transport path 101 has multiple rollers and continues from the paper feed unit 100, through the image forming unit 120 and the reading unit 140, to the paper output tray 150. The image forming unit 120 has a paper inversion path 102 that inverts the paper for double-sided printing. The timing at which the paper is fed by the paper feed unit 100 and the speed at which the paper is transported are controlled by the control unit 110.

The image forming unit 120 forms (prints) an image on paper using a well-known electrophotographic method. The image forming unit 120 has an image forming engine 121 that transfers a toner image onto paper, and a fixing unit 122 that fixes the toner image onto the paper. The image forming unit 120 is controlled by the control unit 110 so that printing is synchronized with the paper transport timing and transport speed.

The image forming engine 121 is a well-known tandem type image forming engine. The image forming engine 121 has multiple photoconductor drums 124 and toner units 125 for each color. Therefore, the image forming engine 121 is a toner image forming unit.

Note that some of the reference numbers for the multiple photoconductor drums 124 and toner units 125 have been omitted.

A toner image (latent image) of each of the colors yellow (Y), magenta (M), cyan (C), and black (K) is formed on each of the multiple photoconductor drums 124. The toner images are sequentially superimposed and primarily transferred to the intermediate transfer belt 123. The toner image primarily transferred to the intermediate transfer belt 123 is secondarily transferred to paper. Any one or all of the YMCK toners is the first toner.

The image forming engine 121 further includes a photoconductor drum 124 and a toner unit 125 for forming a special color toner image. The special color toner is the second toner. The special color is, for example, white (W (White)).

When forming an image using spot color toner, the image forming engine 121 forms a spot color toner image on the photoconductor drum in the same manner as for YMCK toner, and performs primary transfer by overlapping the image with the YMCK toner onto the intermediate transfer belt 123. The YMCK toner and spot color toner images primarily transferred onto the intermediate transfer belt 123 are then secondarily transferred onto paper.

The fixing unit 122 simultaneously fixes the toner image made of YMCK toner and special color toner transferred to the paper at a predetermined fixing temperature. The fixing temperature is controlled by the control unit 110.

The reading unit 140 is located downstream of the image forming unit 120 in the paper transport direction. The reading unit 140 reads the image on the paper after printing. The reading unit 140 is also provided with a gloss meter 141.

The reading unit 140 has a first inline sensor 401 that reads the top surface of the paper on the transport path 101, and a second inline sensor 402 that reads the bottom surface of the paper.

The gloss meter 141 is provided at a position where it can measure the gloss value of the top surface of the paper. The gloss value of the image is obtained by measuring the paper on which an image is printed with the gloss meter 141. However, the gloss meter 141 may also be provided so that it can measure the gloss of both sides of the paper, similar to an inline sensor.

The reading unit 140 and the gloss meter 141 are controlled by the control unit 110. The image data read by the reading unit 140 and the gloss value measured by the gloss meter 141 are sent to the control unit 110 and stored in the memory unit 20.

A paper output tray 150 is attached downstream of the reading unit 140.

Figure 2 is a block diagram showing a control system of the image forming device 1 according to one embodiment. The image forming device 1 has a control unit 110 in the image forming unit 120. The control unit 110 controls each part of the image forming device 1. The control unit 110 and each part of the image forming device 1 are connected by signal lines 60 as shown in Figure 2.

The control unit 110 is a computer and includes a CPU 10, a memory unit 20, a communication interface (I/F) 30, etc. In addition, an operation display unit 40 is connected to the control unit 110.

The CPU 10 controls each part and performs various calculations based on various programs and data.

The storage unit 20 is composed of a ROM that stores various programs and data in advance, a RAM that temporarily stores programs and data as a working area for the CPU 10, and a hard disk that stores various programs and data. The storage unit 20 also stores image data used for image formation. The image data used for image formation includes job data received from an external device and data of a specified test image. Furthermore, the storage unit 20 stores the fixing temperature to be set in the fixing unit 122, as described below.

The communication interface 30 connects the image forming device 1 and an external device via data communication. The external device is, for example, a computer, and transmits job data to the image forming device 1. The communication interface 30 may be, for example, a network interface based on standards such as SATA, PCI Express, USB, Ethernet (registered trademark), or IEEE 1394, or a wireless communication interface such as Bluetooth (registered trademark) or IEEE 802.11.

The operation display unit 40 includes a touch panel display, a numeric keypad, a start button, a stop button, etc. The operation display unit 40 displays the status of each part, image data, etc. The operation display unit 40 is also used to input instructions from the user, such as various settings related to image formation.

In this embodiment, the control unit 110 in the image forming unit 120 controls each part of the image forming device 1. However, the embodiment is not limited to this, and each part of the image forming device 1 may be controlled by a control computer provided outside the image forming unit 120.

Next, we will explain the process for optimizing the fixing conditions for simultaneous use of YMCK toners and special color toners.

Figures 3 to 6 are flowcharts showing the process steps for optimizing the fixing conditions for simultaneous use of YMCK toners and special color toners.

First, the control unit 110 determines whether there is information on the fixing conditions of the spot color toner to be used from the memory unit 20 (S101). The spot color toner to be used is, for example, the spot color toner set in the image forming device 1.

The information on the fixing conditions for the special color toner is one of the image forming conditions for forming a good image, and in this embodiment, it is the fixing temperature range that results in a good gloss of the image formed with the special color toner.

Information on the fixing conditions for the spot color toner is stored in the memory unit 20, for example as a library.

The library records the fixing temperature, which is the result of processing, for the spot color toner for which this processing procedure has previously been performed, along with the ID (identification) of the spot color toner. The library may also record the fixing temperature range that provides good gloss for the spot color toner, as in the example described below.

The library may be stored in a storage medium or an information processing device other than the storage unit 20 in the image forming device 1 and then read from there into the storage unit 20. The storage medium is, for example, a portable storage medium such as a Universal Serial Bus (USB) memory. The information processing device may be, for example, a personal computer (PC) or server connected via a network, or a mobile information terminal (smartphone, tablet, etc.).

The library records the fixing temperature range at which good gloss can be obtained for each paper used, along with the ID of the spot color toner. For example, the ID of the spot color toner can be anything that can identify the spot color toner, such as the manufacturer name, product name, and product number. Paper is identified, for example, by the paper manufacturer name, product name, product number, and paper specifications.

It is also preferable that the library records suitable fixing conditions for use not only for spot color toners, but also for general YMCK toners. By recording the fixing conditions for YMCK toners in the library, they can be read from the same library and used to set the above usable window.

For example, the library records multiple papers for each toner type and ID, as shown in Table 1 below, and the fixing temperature range that provides good gloss for each paper.

In step S101, if the information on the fixing conditions for the spot color toner is in the memory unit 20 (S102: YES), the control unit 110 determines whether the fixing temperature of the spot color toner is within the usable window (S110). The usable window refers to the fixing temperature range in which the spot color toner can be fixed simultaneously with the YMCK toner.

In the example shown in Table 1, when using KM Company J Paper (Konica Minolta J Paper manufactured by Konica Minolta, Inc.), the appropriate fixing temperature range for YMCK toner is 170 to 190°C. Therefore, the usable window is in the range of 170 to 190°C.

For white toner, which is a special color toner, the appropriate fixing temperature range for KM's W1 white toner is 170 to 190°C. Therefore, the fixing temperature of KM's W1 white toner is within the usable window.

In addition, the appropriate fixing temperature range for Company A's W001 white toner is 190 to 200°C. Therefore, the fixing temperature of Company A's W001 white toner is within the usable window.

On the other hand, the appropriate fixing temperature range for Company B's W123 white toner is 195 to 200°C. Therefore, the fixing temperature of Company B's W123 white toner is not within the usable window.

If it is determined in step S110 that the toner is within the usable window (S110: YES), the control unit 110 outputs to the operation display unit 40 that the spot color toner and YMCK toner to be used can be used simultaneously without changing the settings (S111). The operation display unit 40 displays, for example, "Spot color toner and YMCK toner can be used simultaneously." The output in step S111 may be output to an external information processing device, etc.

On the other hand, if it is determined in step S110 that the toner is not within the usable window (S110: NO), the control unit 110 outputs a warning to the operation display unit 40 indicating that the spot color toner and YMCK toner to be used cannot be used simultaneously (S112). The operation display unit 40 displays, for example, "Spot color toner and YMCK toner cannot be used simultaneously." The output in step S112 may be output to an external information processing device, etc.

In step S101, if the memory unit 20 does not contain information on the fixing conditions for the spot color toner to be used (S101: NO), the control unit 110 tests the spot color toner to be used by the following steps.

First, the control unit 110 sets the fixing temperature from the appropriate fixing temperature range for YMCK toner (S102). The control unit 110 selects and sets, for example, the median value from the appropriate fixing temperature range for YMCK toner stored in the storage unit 20. The appropriate fixing temperature range for YMCK toner uses, for example, the appropriate fixing temperature range registered in the library such as that shown in Table 1 above. Note that the fixing temperature may be arbitrarily set by the user from the appropriate fixing temperature range for YMCK toner.

Then, the control unit 110 starts conveying the paper, causes the image forming engine 121 to form a toner image using the special color toner, and causes the fixing unit 122 to fix the image on the paper (S103). The fixing temperature at this stage is the fixing temperature set in S102 if the process goes to step S103 after step S102, and is the fixing temperature set in S120 or 130 if the process goes to step S103 after step S120 or 130 described below.

Next, the control unit 110 uses the gloss meter 141 to measure the gloss of the paper after the image has been formed (S104). The position at which the gloss meter 141 measures the gloss value may be the entire surface of the paper, or only the position at which the image has been formed with the special color toner. For example, the position at which the test image using the special color toner will be formed on the paper is determined in advance, and the gloss meter 141 measures that position. Conversely, the test image may be formed according to the installation position of the gloss meter 141 within the image forming device.

Next, it is determined whether the glossiness of the image is within a predetermined glossiness range. To this end, the control unit 110 compares the glossiness value acquired in step S104 with the predetermined glossiness range, and determines whether the acquired glossiness value is within the predetermined glossiness range (S105).

The range of the predetermined gloss value is determined in advance, for example, by visual evaluation. For example, in the visual evaluation, the gloss is evaluated from image samples with different gloss levels by a user (including not only the operator of the image forming device 1 but also clients of the printing company, etc.). The upper and lower limits of the allowable gloss are determined by the visual evaluation. Then, the images with the upper and lower limits of the gloss obtained by the visual evaluation are measured by the gloss meter 141. The gloss values obtained by the measurement by the gloss meter 141 are set as the upper and lower limits of the predetermined gloss value. The obtained range of gloss values is stored in the memory unit 20, and is read out and used at the start of this step or this processing procedure. Note that the gloss meter used in the above visual evaluation is not limited to the gloss meter 141 built into the image forming device 1. However, when using a gloss counter other than the gloss meter built into the image forming device 1, it is necessary to match the measurement value with the gloss meter 141 built into the image forming device 1.

In step S105, if the gloss value acquired in step S104 is within the range of the predetermined gloss value (S105: YES), the control unit 110 stores the currently set fixing temperature in the memory unit 20 as the fixing temperature at which the spot color toner and the YMCK toner can be used simultaneously (S106). The currently set fixing temperature is the fixing temperature at which the fixing operation was performed in step S103 (and so on below). As already explained, the fixing temperature to be stored is recorded as a fixing condition in the library together with the ID of the spot color toner, for example.

Then, the control unit 110 outputs to the operation display unit 40 that the tested spot color toner can be used simultaneously with the YMCK toner (S107). The operation display unit 40 displays, for example, "Spot color toner and YMCK toner can be used simultaneously." Step S107 is the output of the determination result as to whether the tested spot color toner can be used simultaneously with the YMCK toner. The output in step S107 may be output to an external information processing device, etc.

After that, the control unit 110 ends the processing.

In step S105, if the gloss value acquired in step S104 is below the predetermined range (S105: LOW), the control unit 110 adds a predetermined temperature to the currently set fixing temperature to reset the fixing temperature (S120). The predetermined temperature is set arbitrarily by the user (same below). The predetermined temperature is, for example, 5°C (same below).

Next, the control unit 110 judges whether the fixing temperature after resetting exceeds the upper limit temperature (predetermined upper limit temperature) of the appropriate fixing temperature range for YMCK toner (S121). If the fixing temperature after resetting exceeds the upper limit temperature of the appropriate fixing temperature range for YMCK toner (S121: YES), the control unit 110 outputs a warning to the operation display unit 40 indicating that the tested spot color toner cannot be used simultaneously with the YMCK toner (S122). The operation display unit 40 displays, for example, "Spot color toner and YMCK toner cannot be used simultaneously." Step S122 is an output of the judgment result as to whether the tested spot color toner can be used simultaneously with the YMCK toner. The output in step S122 may be output to an external information processing device or the like. Thereafter, the control unit 110 ends the process.

In step S121, if the reset fixing temperature does not exceed the upper limit temperature of the appropriate fixing temperature range for YMCK toner (S121: NO), the control unit 110 returns to step S103 and continues the subsequent processing.

In step S105, if the gloss value obtained in step S104 exceeds the range of the predetermined gloss value (S105: HI), the control unit 110 subtracts the predetermined temperature from the currently set fixing temperature and resets the fixing temperature (S130).

Next, the control unit 110 judges whether the fixing temperature after resetting is less than the lower limit temperature (predetermined lower limit temperature) of the appropriate fixing temperature range for YMCK toner (S131). If the fixing temperature after resetting is less than the lower limit temperature of the appropriate fixing temperature range for YMCK toner (S131: YES), the control unit 110 outputs a warning to the operation display unit 40 indicating that the tested spot color toner cannot be used simultaneously with the YMCK toner (S132). The operation display unit 40 displays, for example, "Spot color toner and YMCK toner cannot be used simultaneously." Step S132 is an output of the judgment result of whether the tested spot color toner can be used simultaneously with the YMCK toner. The output in step S132 may be output to an external information processing device or the like. Thereafter, the control unit 110 ends the process.

In step S131, if the reset fixing temperature is not lower than the lower limit temperature of the appropriate fixing temperature range for YMCK toner (S131: NO), the control unit 110 returns to step S103 and continues the subsequent processing.

Through the above process, this embodiment determines and stores the fixing conditions under which the special color toner can be used simultaneously with the YMCK toner, and can set the fixing temperature to an appropriate temperature.

In addition, in this embodiment, the fixing temperature is increased in stages until it exceeds a predetermined upper limit temperature, and if the gloss value measured during that time falls within the range of good gloss values, the fixing temperature at that time is stored, and if it does not fall within the range of good gloss values, it is disabled.

In addition, in this embodiment, the fixing temperature is gradually lowered until it falls below a predetermined lower limit temperature, and if the gloss value measured during this process falls within the appropriate gloss value range, the fixing temperature at that time is stored, and if it does not fall within the appropriate gloss value range, it is disabled.

As an example, YMCK toner and special color toner were used, images were formed at different fixing temperatures, and the gloss value and visual gloss were evaluated.

The YMCK toner and special color toner were manufactured according to the toner manufacturing method described in JP-A-2003-5424. The specific manufacturing method is as follows:

(Magenta (M) toner)
0.90 kg of sodium n-dodecyl sulfate and 10.0 L of pure water were added and dissolved by stirring. 1.20 kg of Regal 330R (carbon black manufactured by Cabot Corporation) was gradually added to this solution, and after stirring well for 1 hour, the solution was continuously dispersed for 20 hours using a sand grinder (medium-type disperser). This was designated "colorant dispersion 1". A solution consisting of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 L of ion-exchanged water was designated "anionic surfactant solution A".

A solution consisting of 0.014 kg of nonylphenol polyethylene oxide 10 mole adduct and 4.0 L of ion-exchanged water was designated "nonionic surfactant solution B."

A solution of 223.8 g of potassium persulfate dissolved in 12.0 L of ion-exchanged water was designated "initiator solution C."

3.41 kg of wax emulsion (polypropylene emulsion with number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%), the entire amount of "anionic surfactant solution A" and the entire amount of "nonionic surfactant solution B" were placed in a 100 L glass-lined (GL) reaction vessel equipped with a temperature sensor, cooling tube and nitrogen introduction device, and stirring was started. Next, 44.0 L of ion-exchanged water was added.

Heating was then started, and when the liquid temperature reached 75°C, the entire amount of "Initiator Solution C" was added dropwise. Thereafter, while controlling the liquid temperature at 75±1°C, a premixed solution of 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan was added dropwise. After the addition was complete, the liquid temperature was raised to 80±1°C, and the mixture was heated and stirred for 6 hours to complete the polymerization. The liquid temperature was then cooled to below 40°C, stirring was stopped, and the mixture was filtered through a Paul filter, resulting in "Latex 1-A".

The resin particles in "Latex 1-A" had a glass transition point of 57°C, a softening point of 121°C, a weight-average molecular weight of 12,700, and a weight-average particle size of 120 nm.

A solution of 0.055 kg of sodium dodecylbenzenesulfonate dissolved in 4.0 L of ion-exchanged pure water was designated "anionic surfactant solution D." A solution of 0.014 kg of nonylphenol polyethylene oxide 10 mole adduct dissolved in 4.0 L of ion-exchanged water was designated "nonionic surfactant solution E."

A solution of 200.7 g of potassium persulfate (Kanto Chemical) dissolved in 12.0 L of ion-exchanged water was used as "initiator solution F."

3.41 kg of wax emulsion (polypropylene emulsion with number average molecular weight of 3000: number average primary particle size = 120 nm, solids concentration = 29.9%), the entire amount of "anionic surfactant solution D" and the entire amount of "nonionic surfactant solution E" were placed in a 100 L GL reaction kettle equipped with a temperature sensor, cooling tube, nitrogen introduction device and comb baffle, and stirring was started.

Next, 44.0 L of ion-exchanged water was added. Heating was started, and when the liquid temperature reached 70°C, "initiator solution F" was added.

Next, a premixed solution of 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecyl mercaptan was added dropwise. After the addition was completed, the liquid temperature was controlled to 72°C ± 2°C and heated and stirred for 6 hours, after which the liquid temperature was raised to 80°C ± 2°C and heated and stirred for 12 hours to complete the polymerization.

Then, the liquid temperature was cooled to below 40°C, stirring was stopped, and the liquid was filtered through a Paul filter to give "Latex 1-B."

The resin particles in "Latex 1-B" had a glass transition point of 58°C, a softening point of 132°C, a weight-average molecular weight of 245,000, and a weight-average particle size of 110 nm.

A solution of 5.36 kg of sodium chloride as a salting-out agent dissolved in 20.0 L of ion-exchanged water was named "Sodium Chloride Solution G."

20.0 kg of "Latex 1-A", 5.2 kg of "Latex 1-B", 0.4 kg of "Colorant Dispersion 1", and 20.0 kg of ion-exchanged water prepared above were placed in a 100 L SUS reaction kettle equipped with a temperature sensor, cooling tube, nitrogen introduction device, and particle size and shape monitoring device, and stirred.

After leaving it for 10 minutes, the temperature was raised and the liquid temperature was raised to 85°C in 60 minutes. The liquid was heated and stirred at 85±2°C to cause salting out/fusion while growing the particle size. When the average particle size of the fused particles reached 3 μm, "Sodium Chloride Solution G" was added to stop the particle size growth. This liquid was named "Fused Particle Dispersion 1".

Similarly, liquids were prepared in which the average particle size of the fused particles had been grown to 4 μm and 6 μm, and these were designated "Fused Particle Dispersion Liquid 2" and "Fused Particle Dispersion Liquid 3."

Next, 5.0 kg of the above "Fused Particle Dispersion 1" to "Fused Particle Dispersion 3" were placed in a 5 L reaction vessel equipped with a temperature sensor and cooling tube, and the mixture was heated and stirred at a liquid temperature of 92±2°C while observing the change in shape of the fused particles until the average shape coefficient reached 0.98 or more, thereby carrying out a spheroidizing process for the fused particles. These were designated "Spherical Particle Dispersion 1" (average particle size 3 μm), "Spherical Particle Dispersion 2" (average particle size 4 μm), and "Spherical Particle Dispersion 3" (average particle size 6 μm).

Next, 1 kg of "Spherical Particle Dispersion 1" to "Spherical Particle Dispersion 3" and 1 kg of glass beads with an average particle size of 0.6 mm were placed in a sand grinder (medium-type disperser; inner diameter 200 mm, stirring disk diameter 180 mm) and continuously stirred at 85±2°C and 500 rpm for 0.5 to 8 hours to perform flattening treatment. After the treatment for the specified time, the mixture was cooled to 40°C or less, and after stirring was stopped, the glass beads were removed by passing the mixture through a sieve with a mesh size of 200 mesh, and then the wet cake-like flat black particles were filtered out using a Nutsche. After washing and filtering three times with ion-exchanged water, the wet cake-like flat black particles were pre-dried using a flash jet dryer at an intake temperature of 50°C, and further dried at a temperature of 55°C using a fluidized bed dryer to produce "flat magenta particles".

A specified amount of hydrophobic silica fine particles R805 was externally added to each of the obtained "flat magenta particles" in a Henschel mixer to produce "magenta toner (M toner)."

(Yellow (Y) Toner)
A "yellow toner (Y toner)" was produced in the same manner as in the production of the magenta toner, except that 1.05 kg of C.I. Pigment Yellow 17 was used instead of C.I. Pigment Red 122 as the colorant.

(Cyan (C) Toner)
A "cyan toner (C toner)" was produced in the same manner as in the production of the magenta toner, except that 0.6 kg of C.I. Pigment Blue 15:3 was used instead of C.I. Pigment Red 122 as the colorant.

(Black (K) toner)
A "black toner (K toner)" was produced in the same manner as in the production of the magenta toner, except that 1.2 kg of Regal 330R (carbon black manufactured by Cabot Corporation) was used as the colorant instead of C.I. Pigment Red 122.

(White (W) Toner)
In the production of the magenta toner, 1.6 kg of titanium oxide was used as the colorant instead of C.I. Pigment Red 122. In addition, the amounts of styrene and n-butyl acrylate used in the above Latex 1-B were changed as shown in Table 2 below, and five types of "white toner (W toner)" W-1 to W-5 were produced. The other components were the same as those in the production of the magenta toner.

The physical properties of each finished toner are shown in Table 3 below. One type of YMCK toner was used. Five types of white toner, W-1 to W-5, were used as special color toners. The physical properties of toners W-1 to W-5 are slightly different from those of YMCK toners, even though the amounts of raw materials used are the same as those of YMCK toners, due to differences in pigments, etc.

(Preparation of Developer)
Each of the toners obtained as described above was mixed with a ferrite carrier having a diameter of 45 μm coated with a styrene-acrylic resin to prepare yellow, magenta, cyan, black, and white toners. The toner charge amount of the obtained developer was in the range of −20 to −25 μC/g.

(Image Formation)
The image formation was performed by using a color image forming apparatus similar to that of the embodiment, while changing the fixing temperature. The toner used was mixed with the developer as described above.

The image formation conditions other than the fixing temperature are as follows:

Process speed: 220 mm/sec (40 sheets/min. for A4 horizontal feed),
Charge potential (potential of unexposed area): -750V,
Maximum exposed area potential: -30V or less (between 0 and -30V),
Development: Two-component non-contact development with DC+AC applied. The DC bias is fixed at -650V, the AC frequency is fixed at 8kHz, and the amplitude of the AC bias and the number of rotations of the developing roller are changed to set the optimum conditions.
Transfer: Change the transfer bias to set the optimum conditions.

The paper used was "Konica Minolta J Paper" manufactured by Konica Minolta, Inc. (KM Company) with a basis weight of 64 g/m ² .

(Gloss value measurement)
The image-formed portion of the paper was measured with a gloss meter to obtain the gloss value of the image. The gloss meter used was a GM-268A (measurement angle 60°) manufactured by Konica Minolta, Inc.

Table 4 shows the gloss values for each toner at each fixing temperature.

(Visual evaluation method)
Furthermore, three subjects were asked to evaluate the glossiness of the formed image. The evaluation criteria were to answer the question "Which glossiness would be best for a menu item at a high-end restaurant?" with ◯ (preferred) or × (unpreferred). ◯ was given 1 point and × was given 0 point, and a glossiness value of 2 points or more was considered to be the appropriate glossiness.

In Table 4, gloss values that were visually evaluated as having good gloss are marked with an "*" before the numerical value.

(Evaluation results)
As a result of the above gloss values and visual evaluation, it is found that a good gloss value range for YMCK toner is 40 to 65. It is also found that the fixing temperature range that provides this gloss value range is 170 to 190° C. This fixing temperature range is the appropriate fixing temperature range for obtaining good images with YMCK toner.

On the other hand, the preferred gloss value range for white toner varies from W-1 to W-5: 30 to 45 for W-1, 30 to 37.5 for W-2, 30 to 33.75 for W-3, 33.75 to 45 for W-4, and 33.75 to 45 for W-5.

Therefore, it can be seen that the white toner that provides good gloss values within the appropriate fixing temperature range for YMCK toners is 170 to 190°C for W-1. It can also be seen that only 190°C can be used for W-2. It can also be seen that only 170°C can be used for W-4. On the other hand, it can be seen that W-3 and W-5 cannot be used simultaneously with YMCK toners.

The above-described embodiments and examples provide the following advantages:

In the embodiment described above, first, an image formed with the second toner, the special color toner, is fixed within the appropriate fixing temperature range of the first toner, the YMCK toner. Then, in the embodiment, if the gloss of the image formed with the second toner is good, the fixing temperature at that time is set to a fixing temperature that allows simultaneous use of the YMCK toner and the special color toner. Therefore, in the embodiment, an image can be formed under image formation conditions that allow simultaneous use of the YMCK toner and the special color toner, so that a good image can be obtained by using the YMCK toner and the special color toner simultaneously. As a result, in one embodiment, the productivity is improved because the YMCK toner and the special color toner can be used simultaneously.

In one embodiment, if the gloss of an image formed with a special color toner is not good within the appropriate fixing temperature range of the YMCK toner, a warning is output indicating that the special color toner and the YMCK toner cannot be used simultaneously. Therefore, in one embodiment, it is possible to prevent poor gloss caused by the simultaneous use of two or more types of toner with incompatible image forming conditions.

Although the embodiments and examples have been described above, the present invention is not limited to the embodiments and examples, and various combinations are possible.

In the above-mentioned embodiment and examples, tests were conducted using plain paper to determine the fixing temperature at which YMCY toners and white toners can be used simultaneously. It is preferable to conduct such tests each time a different paper is used. This is because when the basis weight of the paper changes, the heat transfer characteristics also change, and so the gloss changes even at the same fixing temperature. In addition, the gloss also changes when the surface roughness of the paper changes.

For example, when using Company A's plywood (plastic-like paper) as the paper, a good gloss value for an image made with YMCK toner is 48 to 78. On the other hand, visual evaluation shows that a good gloss value for an image made with white toner is 36 to 54.

Similarly, when using Company B's price, a good gloss value for an image made with YMCK toner is 48 to 78. On the other hand, visual evaluation shows that a good gloss value for an image made with white toner is 36 to 54.

In this embodiment, even for these types of toners, by performing the above-mentioned tests, if there is a fixing temperature within the appropriate fixing temperature range where good gloss values can be obtained with YMCK toners that can obtain good gloss values for images using white toner, that fixing temperature is set as the fixing temperature that can be used simultaneously.

In addition, in this embodiment, in the case of price, if there is no fixing temperature that can obtain a good gloss value for an image using white toner within the appropriate fixing temperature range that can obtain a good gloss value for YMCK toners, it is output that simultaneous use is not possible.

In the above-described embodiment and examples, a white toner has been used as an example of the special color toner, which is the second toner. However, the second toner of the present invention may be a special color toner other than white. The second toner may be, for example, a metallic toner such as gold or silver, or a transparent toner.

In addition, in the above-described embodiment and examples, YMCK toner has been used as an example of the first toner. However, the first toner of the present invention may be a toner other than YMCK toner.

In the above-described embodiment and example, an example was described in which four colors of toner, YMCK, are used simultaneously as the first toner. However, the first toner may be at least one of the colors of toner, YMCK.

In the above-described embodiment, flat particle toner was produced by flattening the YMCK toner and the white toner. However, the particle shapes of the first toner and the second toner are not particularly limited.

In addition, the conditions and numerical values used in the description of the embodiments are for illustrative purposes only, and the present invention is not limited to these conditions and numerical values. The present invention can be modified in various ways based on the configuration described in the claims, and these modifications are also within the scope of the present invention.

1...Image forming apparatus,
10...CPU,
20...Memory unit,
40...Operation display unit,
100...paper feed unit,
101...Transport path,
110...control unit,
120...image forming unit,
121...image forming engine,
123... intermediate transfer belt,
140...Reading unit,
150...Paper output tray.

Claims (15)

An image forming method for forming and fixing an image on an image forming medium using a first toner and a second toner,
(a) fixing an image formed by the second toner on the image forming medium at a fixing temperature within a preset appropriate fixing temperature range of the first toner;
a step (b) of determining whether the gloss of the image fixed by the step (a) is within a predetermined gloss range;
(c) setting the fixing temperature used in the step (a) as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium when the determination result of the step (b) is within the range of the predetermined gloss level; and
having
the first toner is at least one of yellow, magenta, cyan, and black toner;
The image forming method, wherein the second toner is a special color toner. The image forming method according to claim 1, wherein the special color toner is a white toner. a step (a1) of fixing an image formed by the second toner on the image forming medium at a fixing temperature increased by a preset temperature from the fixing temperature of the step (a) when the result of the determination of the step (b) is less than the lower limit of the predetermined glossiness;
After the step (a1), a determination is made according to the step (b), and if the determination result is within the range of the predetermined glossiness, the fixing temperature used in the step (a1) is set as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium.
3. The image forming method according to claim 1, wherein if the determination result of step (b) is not within the predetermined range of glossiness, step (a1) and step (b) are repeated until the glossiness is within the predetermined range. The image forming method according to claim 3, further comprising a step (d1) of outputting a warning if the result of the determination in step (b) is less than the lower limit of the predetermined glossiness after repeating step (a1) and step (b) until the fixing temperature reaches a predetermined upper limit temperature. and a step (a2) of fixing an image formed by the second toner on the image forming medium at a fixing temperature lowered by a preset temperature from the fixing temperature in the step (a) when the result of the determination in the step (b) exceeds the upper limit of the predetermined gloss level,
After the step (a2), a step (c2) is performed to determine whether the gloss level is within the predetermined range. If the result of the determination is within the predetermined range, the fixing temperature used in the step (a1) is set as the fixing temperature when forming an image using the first toner and the second toner and fixing the image on the image forming medium.
4. The image forming method according to claim 3, wherein if the determination result of step (b) is not within the predetermined range of glossiness, step (a2) and step (b) are repeated until the glossiness is within the predetermined range. The image forming method according to claim 5, further comprising a step (d2) of outputting a warning when the result of the determination in step (b) exceeds the upper limit of the predetermined glossiness as a result of repeating step (a2) and step (b) until the fixing temperature reaches a predetermined lower limit temperature. the predetermined gloss range is defined as a range of predetermined gloss values measured by a gloss meter,
7. The image forming method according to claim 1, wherein in the step (b), the image fixed on the image forming medium is measured by the gloss meter and compared with the range of gloss values to determine the gloss value. An image forming program for causing a computer to execute the image forming method according to any one of claims 1 to 7. a toner image forming unit that forms an image on an image forming medium using the first toner and the second toner;
a fixing section for fixing the image formed by the toner onto the image forming medium;
a storage unit that stores a fixing temperature of the fixing unit;
a control unit that sets the fixing temperature in the fixing unit to a fixing temperature within an appropriate fixing temperature range for the first toner, fixes an image formed with the second toner onto the image forming medium, determines whether or not the gloss of the fixed image is within a predetermined gloss level range, and, if the determination result is within the predetermined gloss level range, stores the fixing temperature set in the fixing unit in the storage unit as the fixing temperature when an image is formed with the first toner and the second toner and fixed onto the image forming medium;
having
the first toner is at least one of yellow, magenta, cyan, and black toner;
The second toner is a special color toner. The image forming apparatus according to claim 9, wherein the special color toner is white toner. when the determination result is less than the lower limit of the predetermined glossiness, the control unit resets the fixing temperature of the fixing unit to a fixing temperature that is increased by a preset temperature from the fixing temperature set in the fixing unit, and fixes a new image formed with the second toner on the image forming medium;
An image forming apparatus as described in claim 9 or claim 10, further comprising: determining whether the gloss of an image fixed at the reset fixing temperature is within the range of the specified gloss level; and if the result of the determination is within the range of the specified gloss level, storing the reset fixing temperature in a memory unit as the fixing temperature when forming an image using the first toner and the second toner and fixing it to the image forming medium. The image forming device according to claim 11, wherein the control unit repeats resetting of the fixing temperature and fixing of the image with the second toner until the fixing temperature reaches a predetermined upper limit temperature, and outputs a warning when the determination result is below the lower limit of the predetermined glossiness. when the determination result exceeds the upper limit of the predetermined gloss level, the control unit resets the fixing temperature of the fixing unit to a fixing temperature lowered by a preset temperature from the fixing temperature set in the fixing unit, and fixes a new image formed with the second toner on the image forming medium;
An image forming apparatus as described in claim 9 or claim 10, which determines whether the gloss of an image fixed at the reset fixing temperature is within the specified gloss range, and if the result of the determination is within the specified gloss range, stores the reset fixing temperature in the memory unit as the fixing temperature when forming an image using the first toner and the second toner and fixing it to the image forming medium. The image forming device according to claim 13, wherein the control unit repeats resetting the fixing temperature and the image fixing operation using the second toner until the fixing temperature reaches a predetermined lower limit temperature, and outputs a warning if the result of the determination after resetting exceeds the upper limit of the predetermined glossiness. a gloss meter that is located downstream of the fixing unit in a transport direction of the image-forming medium and that measures the gloss of the image-forming medium;
the predetermined gloss range stored in the memory unit is defined as a predetermined gloss value range measured by the gloss meter,
The control unit compares the gloss value of the image formed with the second toner obtained by measuring the image forming medium with the gloss meter with the predetermined gloss value range, and determines whether the gloss value of the image formed with the second toner is within the predetermined gloss value range.