JPH10297008A - Method and system for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To superpose various types of ink image without disturbing previously transferred ink images by setting the thermal capacity, the quantity, the fusion transfer temperature of a fusible ink being fusion transferred at a specified number of order and the quantity of heat for transferring ink at room temperature within specified ranges. SOLUTION: Assuming the thermal capacity of a thermally fusible ink to be fused at n-th time (n=1, 2,..., i) is Cn , the quantity thereof is Wn , the fusion transfer temperature thereof is Tn and the room temperature is Tr , the quantity of heat Qn for fusion transferring the n-th thermally fusible ink must satisfy a formula. An image forming system 1 comprises an intermediate transfer body 100, and a unit 110 for transferring yellow, magenta and cyan ink image forming parts 1Y, 1M and 1C, while superposing, to record three different kinds of ink image (yellow, magenta, cyan) onto the intermediate transfer body 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fusion type thermal transfer type image forming method and an image forming apparatus using a heat fusible ink.

[0002]

2. Description of the Related Art In order to reduce the running cost of a conventional thermal transfer printer, the present inventor has proposed a thermal transfer system using a porous ink sheet. According to this method, the running cost can be reduced, and the ink image can be efficiently transferred and formed on the recording medium with little heat energy.

In general, in an image forming apparatus for forming a color image, a so-called tandem type image forming apparatus in which ink images of respective colors are superimposed on an intermediate transfer member is promising because the output speed of the image can be increased. is there.

Further, when configuring this tandem type image forming apparatus, it is necessary to make the recording time of each color the same.

However, in the tandem-type thermal transfer color image forming apparatus, there is a problem that the previously melt-transferred ink image is disturbed by re-melting when an ink image to be subsequently melt-transferred is overlaid. was there.

Therefore, for example, as described in Japanese Patent Application Laid-Open No. 4-41284, a method has been proposed in which inks differing only in the melting temperature are used.

[0007]

However, when a plurality of types (colors) of heat-meltable inks having different melting temperatures are used, the time required for melt-transferring each type of the heat-meltable ink is different. There is a problem that it is difficult to configure the image forming apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the recording time can be easily made the same for each type, and the previously transferred ink image can be transferred later. It is an object to provide an image forming method and an image forming apparatus which are not disturbed when forming an ink image.

[0009]

To achieve this object, an image forming method according to claim 1 is an image forming method for forming an image by melting and transferring a plurality of types of heat-meltable inks, The heat capacity of the n-th (n = 1, 2,..., i) -th heat-meltable ink is C _n , the amount of the n-th heat-meltable ink is W _n , that hot melt ink temperature T _n of melt transfer and when the room temperature and T _r, the heat quantity Q _n at the time of melt transfer the n-th heat-meltable ink,

[0010]

(Equation 1)

It is characterized by satisfying. At this time, the room temperature _Tr may be a constant value or a measured value.

According to the image forming method of the present invention, the amount of heat applied when transferring the ink image to be transferred later is smaller than the amount of heat for re-melting the ink image transferred earlier. Each type of ink image can be superimposed without disturbing the transferred ink image.

According to a second aspect of the present invention, there is provided an image forming apparatus comprising: a plurality of solid-state heat-fusible inks; and a heat-fusing unit configured to heat-melt the plurality of types of the heat-fusible inks independently for each type. An ink holding unit configured to have an endless shape and independently absorbing and holding the plurality of types of heat-meltable inks heated and melted by the heating and melting unit for each type; Heating each time, melting the heated portion of the ink, successively superimposing and transferring the ink image onto the intermediate transfer member, and forming a desired ink image on the heating recording means; And a thermal transfer unit for melt-transferring a desired ink image formed by superimposing a plurality of types of ink images onto a recording medium, wherein the heating recording unit is an n-th (n = 1, 2,..., I) -th Melt transfer The heat capacity of the click C _n, n-th to the hot melt ink amount to be melt transfer W _n, the temperature for melt transfer the hot-melt ink which is melted transferred to n-th T _n, when was the T _r rt , heat Q _n at the time of melt transfer the n-th heat-meltable ink,

[0014]

(Equation 1)

It is characterized in that it is configured to satisfy the following. At this time, the room temperature _Tr may be a constant value,
It may be a measured value.

According to the image forming apparatus of the present invention, the heating and melting means heats and melts the plurality of kinds of heat-meltable inks independently for each kind, and the ink holding means heats and melts the plurality of kinds of heat melting inks. Ink is independently absorbed and held for each type. The heating recording unit heats the ink holding unit holding the ink for each type of ink, melts the heated portion of the ink, and sequentially superimposes and transfers the ink image onto the intermediate transfer body, thereby transferring a desired image. Form an ink image. At this time, the heat recording unit sets the heat capacity of the n-th (n = 1, 2,..., I) -th heat-meltable ink to be melt-transferred to C _n , and the amount of the n-th heat-meltable ink to be melt-transferred. the W _n, when the temperature of melt transfer the hot-melt ink which is melted transferred to n-th T _n, the room temperature was T _r, heat Q _n at the time of melt transfer the n-th heat-meltable ink,

[0017]

(Equation 1)

It is set so as to satisfy the following. At this time,
The room temperature _Tr may be a constant value or a measured value.

Since the amount of heat applied when the ink image to be transferred later is transferred to the intermediate transfer member is smaller than the amount of heat for re-melting the previously transferred ink image, the previously transferred ink image is not disturbed. The ink image can be overlaid on the intermediate transfer member.

Thereafter, the thermal transfer means melt-transfers the ink image formed by superimposing the plurality of ink images formed on the intermediate transfer member onto a recording medium. Further, although the ink is consumed from the ink holding means, the ink is replenished to the ink holding means again by the heating and melting means, and the melt transfer to the intermediate transfer body is performed.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the ink holding means is formed of a fibrous ceramic in a paper shape.

Since the ink holding means is made of ceramic, the heat resistance is increased, and the ink holding means is not damaged even when repeatedly heated by the heating recording means.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. The image forming apparatus 1 transfers three different types of ink images (for example, yellow, magenta, and cyan) to the intermediate transfer member 100.
A yellow ink image forming unit 1Y, a magenta ink image forming unit 1M, and a cyan ink image forming unit 1C for transferring and recording thereon;
A transfer unit 110 serving as a thermal transfer unit for transferring the ink image formed on the intermediate transfer body 100 to the recording medium 40.

The intermediate transfer member 100 is formed in an endless belt shape, and is stretched over a pair of drive rollers 101 and 102 and a heat roller 111 described later. These drive rollers 101 and 102 and heat roller 111 are provided with a drive motor M
Of the intermediate transfer member 100 in the direction of the arrow in the figure in conjunction with the rotation of the drive motor M. Incidentally, the intermediate transfer member may be not only in a belt shape as in the embodiment but also in a drum shape. The belt is preferably made of a material having excellent heat resistance, such as polyimide.

The transfer unit 110 is rotated at a predetermined speed by the drive motor M and is heated to a predetermined temperature by a built-in heater or the like. The transfer unit 110 is rotatably supported by the shaft and is urged by the heat roller 111. Platen roller 112
It is composed of The leading end of the recording medium 40 fed along a linear paper guide G from outside the apparatus enters the nip between the heat roller 111 and the platen roller 112,
The recording medium 40 is conveyed leftward in FIG. 1 at the same speed as the peripheral speed of the intermediate transfer body 100. The full-color ink image formed on the intermediate transfer body 100 by heating from the heat roller 111 as described later is integrally melted again and transferred to the recording medium 40. Since the moving direction of the intermediate transfer member 100 from the heat roller 111 to the drive roller 101 is away from the recording medium moving direction by the paper guide G, the recording medium 40 is separated from the intermediate transfer member 100 and discharged out of the apparatus.

Next, a yellow ink image forming section 1Y for thermally transferring a yellow ink image to the intermediate transfer member 100, a magenta ink image forming section 1M for thermally transferring a magenta ink image, and cyan for thermally transferring a cyan ink image. The ink image forming unit 1C will be described.

The intermediate transfer member 10 stretched in a substantially horizontal direction
0, the yellow ink image forming section 1Y and the magenta ink image forming section 1 from the upstream side in the moving direction of the intermediate transfer member.
M and a cyan ink image forming unit 1C are sequentially arranged.
Here, it is preferable that the distance between the image forming units is larger than the distance at which the ink image thermally transferred by each image forming unit can be substantially solidified on the intermediate transfer body 100.

Each image forming unit has the same configuration except for the ink used. For this reason, the detailed description of each ink image forming unit describes only the configuration of one of them, the yellow ink image forming unit 1Y, and the other magenta ink image forming unit 1M and cyan ink image forming unit 1C. Detailed description of the configuration is omitted. In addition, for the corresponding members, the reference numerals are suffixed with Y for the yellow ink image forming section, M for the magenta ink image forming section, and C for the cyan ink image forming section.

The yellow ink image forming section 1Y includes a hot-melt ink 10Y, a heater (heating / melting means) 20Y for preheating the hot-melt ink 10Y, and a hot-melt ink 10Y preheated and melted by the heater 20Y. Ink holder 30Y as an ink holding means for holding the formed ink, and a thermal ink for heating the ink holder 30Y and heating the ink held in the ink holder 30Y to melt and transfer the ink to the intermediate transfer member 100. And a head (heating recording means) 50Y.

The hot-melt ink 10Y is formed into a cylindrical shape at room temperature, and is rotatably supported around an axis 11Y. The heat-meltable ink 10Y is rotated at a low speed in conjunction with the drive motor M.

On the other hand, an ink holder 30Y is provided so as to be rotatable around one fixed axis, facing the hot-melt ink 10Y, and the ink holder 30Y is rotatable about a fixed axis 301Y. The holding roller 303Y is made up of a solid columnar holding roller 303Y made of resin and an ink holding sheet 304Y adhered on the outer periphery of the holding roller 303Y. A driven gear 302Y is fixed at a position concentric with the shaft 301Y. The driven gear 302Y meshes with a drive gear 32Y that is rotated at a predetermined speed in conjunction with the drive motor M, and the rotation of the gear causes the holding roller 303 to rotate.
Y and the ink holding sheet 304Y are integrally rotated in the counterclockwise direction in the drawing. The peripheral speed of the ink holding sheet 304 is set to be the same as the rotation speed of the intermediate transfer body 100.

The hot-melt ink 10Y is urged by a spring (urging means) 60Y via a thin stainless steel heater 20Y to the ink holding sheet 304Y on the holding roller 303Y. This heater 20Y is
The ink holding sheet 304Y extends in the width direction of the ink holding sheet 304Y (a direction perpendicular to the paper surface of FIG. 1), and the ink holding sheet 30
A through-hole 21Y connecting the contact surface of 4Y and the contact surface of the hot-melt ink 10 (referred to as a preheating position) is formed along the width direction of the ink holding sheet 304Y. The width of the through hole 21Y is set to be substantially equal to or slightly smaller than the width of the ink holding sheet 304Y, and is set to be substantially the same as or slightly larger than the width of the hot-melt ink 10Y. A heating resistor is provided on the entire surface or a part of the heater 20Y, and the heating resistor is connected to a power supply. The heater 20Y thus configured
Generates heat in accordance with the power supplied from the power supply, and the spring 60
The hot-melt ink 10Y pressed by Y is melted.
The melted ink flows downward through the through hole 21Y of the heater 20Y and is supplied to the ink holding sheet 304Y.

Here, the ink holding sheet 304Y
Is made of alumina and silica as main components, and is formed by adding a ceramic fiber melted and fibrillated at a high temperature and a binder such as a resin to form a paper. Ceramic fibers have a fiber diameter of about 2 μm and a melting temperature of 1700 ° C. Since this ceramic fiber is formed into a paper shape, it has very high electrical insulation and heat resistance, and also has high porosity. The ink melted by the heater 20Y penetrates into this gap and solidifies.

If a large number of through holes extending in the thickness direction are formed in the ink holding sheet 304Y, the molten ink penetrates into the through holes and solidifies.

Here, the configuration of the ink holding member 30Y is not limited to the above-described one, but may be anything as long as it is endless and can hold the hot-melted ink. For example, it may be in the form of a roller or a belt. Preferably, ceramics having excellent heat resistance are preferably used because they are repeatedly rotated and heated.

The ink holding member 30Y is arranged such that the ink holding sheet 304Y comes into contact with the outer peripheral surface of the intermediate transfer member 100.
1Y is set so as to extend in parallel with the rotation axis of the driving rollers 101 and 102. On the other hand, the intermediate transfer member 10
0 and the ink holding sheet 304
On the opposite side of the contact position between Y and the intermediate transfer member 100, a thermal head 50Y in which a number of heating elements are arranged in a row is arranged so as to urge the heating element portion toward the intermediate transfer member 100, The direction in which the heating element extends is the fixed shaft 301Y.
Are set in parallel with each other, and the arrangement dimension of the heating elements is substantially the same as the width dimension of the ink holding sheet 304Y.

The on / off of the heat generation and the heat generation amount of each heating element of the thermal head 50Y are controlled by the controller 200. That is, the controller 200 includes the CPU, RO
A well-known logic operation circuit comprising M and RAM,
When color image data is received from the outside, the data is stored in a RAM, and from that data, yellow image data, magenta image data, and cyan image data (all of which are on / off information of each pixel in a bitmap format) are stored. Each thermal head 50 is separated and stored in a predetermined area of the RAM, and based on image data of each color.
It is configured to control the energization of the heating elements of Y, 50M, and 50C.

Next, the operation of the image forming apparatus 1 configured as described above will be described below with reference to FIGS.

First, the yellow hot-melt ink 10Y
Is heated at the preheating position by the operation of the heater 20Y, the heated portion of the heat-fusible ink 10Y melts, and is once dispersed and held in the ink holding sheet 304Y of the ink holder 30Y. Thereafter, the ink holding body 30Y rotates, and the yellow heat-meltable ink held on the ink holding sheet 304Y moves to the image forming position (the position to be heated by the thermal head 50Y), and the thermal head disposed at this image forming position. The heating element of the head 50Y selectively generates heat by the controller 200 in accordance with the yellow image data, and the amount of heat causes the yellow ink dispersed and held on the ink holding sheet 304Y to be heated and melted, thereby forming an intermediate transfer member. 100 is melt-transferred in an image form. By selectively controlling the heat generation of the heating elements and moving the intermediate transfer member 100 to the left in FIG. 1, the yellow ink corresponding to the yellow image data is formed on the surface of the intermediate transfer member 100 as shown in FIG. Statue 200
Y is formed.

[0041] Here, in the yellow ink image forming unit 1Y, the quantity of heat Q ₁ given when melt transfer the hot-melt ink 10Y dispersed held in the ink holding sheet 304Y to the intermediate transfer member 100, the heat-meltable ink The heat capacity of 10Y is C ₁ , the amount of the heat-fusible ink Y melt-transferred on the intermediate transfer member 100 is W ₁ , the melt transfer temperature when the melt transfer is performed on the intermediate transfer member 100 is T ₁ , and the room temperature is T ₁ . _{If r}

[0042]

(Equation 2)

When applied from the thermal head 50Y so as to satisfy the condition, a yellow ink image 200Y corresponding to the yellow image data is formed on the intermediate transfer member 100.

Next, the intermediate transfer member 100 on which the yellow ink image 200Y has been transferred is formed by driving rollers 101 and 102.
Is moved to the position of the magenta ink image forming section 1M for forming a magenta ink image with the image forming operation.

Then, the yellow ink image forming section 1Y
Similarly to the above, the magenta hot-melt ink 10M once dispersed and held in the ink holding sheet 304M moves to the image forming position while the ink holding sheet 304M rotates and is held by the ink holding sheet 304M. The thermal head 50M disposed at the image forming position generates heat in accordance with the magenta image data, and the amount of heat causes the magenta ink dispersed and held on the ink holding sheet 304M to be heated and melted, so that the intermediate transfer member 100 is heated. As shown in FIG. 2, the intermediate transfer member 100 has a magenta ink image 200M corresponding to the magenta image data.
Is formed so as to overlap the yellow ink image 200Y.

[0046] At this time, the magenta ink image forming unit 1M, a quantity of heat Q ₂ to which is applied at the time of melt transfer the magenta heat-meltable ink 10M dispersed held in the ink holding sheet 304M on the intermediate transfer body 100, magenta hot melt The heat capacity of the fusible ink 10M is C ₂ , the amount of the fusible ink M melt-transferred onto the intermediate transfer member 100 is W ₂ ,
Assuming that the melt transfer temperature at the time of the melt transfer on 0 is T ₂ , the above parameters C ₁ , W ₁ , T ₁ , and _Tr are further used.

[0047]

(Equation 3)

When applied from the thermal head 50M so as to satisfy the condition, the magenta ink image 200M is transferred to the yellow ink image 2 previously transferred and formed on the intermediate transfer member 100.
00Y can be transferred and formed on the intermediate transfer member 100 without being melted and disturbed.

Further, the intermediate transfer member 10 on which the yellow ink image 200Y and the magenta ink image 200M are transferred and formed.
0 is moved to the position of the cyan ink image forming section 1C for forming a cyan ink image by the drive rollers 101 and 102 in accordance with the image forming operation.

Then, the yellow ink image forming section 1
Y, similarly to the magenta ink image forming unit 1M, the cyan hot-melt ink 10C once dispersed and held in the ink holding sheet 304C is in a state where the ink holding sheet 304C rotates and is held on the ink holding sheet 304C. Moves to the image forming position, and the thermal head 50C arranged at this image forming position generates heat according to the cyan image data,
The amount of heat causes the cyan ink dispersed and held on the ink holding sheet 304C to be heated and melted, thereby being melt-transferred to the intermediate transfer member 100, and as shown in FIG. Is formed so as to overlap the yellow ink image 200Y and the magenta ink image 200M.

At this time, in the cyan ink image forming section 1C,
The quantity of heat Q ₃ given when melt transfer the dispersion retained cyan heat-meltable ink 10C in the ink holding sheet 304C on the intermediate transfer member 100, the heat capacity of the hot-melt ink 10C C _3, on the intermediate transfer member 100 Assuming that the amount of the heat-meltable ink C to be melt-transferred is W ₃ and the melt transfer temperature at the time of melt-transfer onto the intermediate transfer member 100 is T ₃ , the above-described parameters C ₁ , W ₁ , T ₁ , Using C ₂ , W ₂ , T ₂ , and _Tr ,

[0052]

(Equation 4)

In order to satisfy the condition, the thermal head 5
When given from 0C, the cyan ink image 200C is superimposed on the intermediate transfer member 100 without disturbing the yellow ink image 200Y and the magenta ink image 200M previously transferred and formed on the intermediate transfer member 100 without re-melting. Transfer formation is possible.

As described in detail above, the yellow ink image 2
2, a color image corresponding to the image signal is formed on the intermediate transfer body 100 on which the magenta ink image 200M and the cyan ink image 200C are transferred and superimposed as shown in FIG. Rollers 101, 10
The transfer device 100 is moved to the position of the transfer device 110 with the rotation of 2, and is melt-transferred to the recording medium 40 such as paper by the transfer device 100, and a color image corresponding to the image data is formed on the recording medium 40.

In this embodiment, the intermediate transfer member 10
Although the order in which the ink images are formed on 0 has been described in the order of yellow, magenta, and cyan, the present invention is not limited to this, and they may be formed on the intermediate medium in any order.

In this embodiment, the case where a color image is formed with three colors of yellow, magenta and cyan is exemplified. For example, when a color image is formed by adding black to the three colors, When the fourth ink image is melt-transferred onto the intermediate transfer member,

[0057]

(Equation 5)

If the above condition is satisfied, the same effects as those of the present embodiment can be obtained.

Further, even when a color image is formed in two colors, the same effect as that of the present embodiment is obtained.

Further, in the present embodiment, a plurality of color inks are exemplified as the plurality of heat-meltable inks. Produces an effect.

[0061]

Next, specific examples of the present invention will be described.

First, as a first embodiment, a case will be described in which only the heat capacities of the heat-meltable inks 10Y, 10M, and 10C of each color are changed.

Here, the main component of the hot-melt ink is
By changing the mixing ratio of the wax and the resin among the coloring material, the wax, and the resin, the heat capacity of the hot-melt ink can be changed. That is, the heat capacity can be increased by increasing the ratio of the wax.

First, a yellow ink image 200Y is formed on the intermediate transfer member 100. At that time, the hot-melt ink 10
The heat capacity of Y is 2 kJ / kg · K, and the amount of the heat-meltable ink 10Y melt-transferred onto the intermediate transfer member 100 is 5 × 10 ^−8.
Assuming that the melt transfer temperature at the time of melt transfer on the intermediate transfer member 100 is 125 ° C. and the room temperature is 20 ° C., the amount of heat given when the heat-meltable ink 10Y is melt-transferred to the intermediate transfer member 100 is 10. If 5 mJ, the intermediate transfer member 100
Is formed with a yellow ink image 200Y corresponding to the image signal.

Thereafter, a magenta ink image 200M is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y. At that time, the heat capacity of the hot-melt ink 10M was set to 1.
5 kJ / kg · K, the amount of the hot-melt ink 10 M that is melt-transferred onto the intermediate transfer member 100 is 5 × 10 ⁻⁸ kg, and the melt transfer temperature when melt-transferred onto the intermediate transfer member 100 is 12
Assuming that the temperature is 5 ° C. and the room temperature is 20 ° C., the amount of heat Q given when the hot-melt ink 10M is melt-transferred to the intermediate transfer member 100
2 is within the range of 7.9 to 10.5 mJ, the magenta ink image 200M can be transferred to the intermediate transfer member 100 without disturbing the yellow ink image 200Y previously transferred and formed on the intermediate transfer member 100 by re-melting. It can be transferred onto the body 100.

Finally, a cyan ink image 200C is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y and the magenta ink image 200M. At this time, the heat capacity of the heat-meltable ink 10C is 1 kJ / kg · K, the amount of the heat-meltable ink 10C melt-transferred on the intermediate transfer member 100 is 5 × 10 ⁻⁸ kg, and the heat transfer is performed on the intermediate transfer member 100. Assuming that the melt transfer temperature at the time of performing is 125 ° C. and the room temperature is 20 ° C.,
If the amount of heat Q3 applied when the hot-melt ink 10C is melt-transferred to the intermediate transfer member 100 is in the range of 5.3 to 18.4 mJ, the cyan ink image 200C is first transferred onto the intermediate transfer member 100. Yellow ink image 2 being formed
00Y and the magenta ink image 200M can be transferred and formed on the intermediate transfer member 100 without being disturbed by re-melting.

As in the first embodiment described above, in order to set the heat capacity of each color ink 10Y, 10M, 10C, for example, the yellow ink 10Y, the magenta ink 10M, and the cyan ink 10C What is necessary is just to raise the ratio of wax in order.

Next, as a second embodiment, a case will be described in which the amounts of the heat-meltable inks 10Y, 10M, and 10C of each color that are melt-transferred onto the intermediate transfer member 100 are changed.

Here, the main component of the hot-melt ink is
By changing the content of the coloring material among the coloring material, wax, and resin, the concentration of the hot-melt ink can be changed.
The ink necessary for obtaining a predetermined density is transferred to the intermediate transfer member 10.
The amount of the melt transfer on zero can be changed.

First, a yellow ink image 200Y is formed on the intermediate transfer member 100. At that time, the hot-melt ink 10
The heat capacity of Y is 2 kJ / kg · K, and the amount of the heat-meltable ink 10Y melt-transferred onto the intermediate transfer member 100 is 5 × 10 ^−8.
Assuming that the melt transfer temperature at the time of melt transfer on the intermediate transfer member 100 is 125 ° C. and the room temperature is 20 ° C., the amount of heat given when the heat-meltable ink 10Y is melt-transferred to the intermediate transfer member 100 is 10. If 5 mJ, the intermediate transfer member 100
Is formed with a yellow ink image 200Y corresponding to the image signal.

Thereafter, a magenta ink image 200M is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y. At this time, the heat capacity of the hot-melt ink 10M was 2 k.
J / kg · K, the amount of the hot-melt ink 10M to be melt-transferred onto the intermediate transfer member 100 is 4 × 10 ⁻⁸ kg, and the melt transfer temperature at the time of melt-transfer onto the intermediate transfer member 100 is 125.
When the temperature and room temperature are set to 20 ° C., the amount of heat Q2 given when the hot-melt ink 10M is melt-transferred to the intermediate transfer member 100.
Is within the range of 8.4 to 10.5 mJ, the magenta ink image 200M is re-melted with the yellow ink image 200Y previously formed on the intermediate transfer member 100 without disturbing the magenta ink image 200M. 100 can be formed by transfer.

Finally, a cyan ink image 200C is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y and the magenta ink image 200M. At this time, the heat capacity of the heat-meltable ink 10C is 2 kJ / kg · K, the amount of the heat-meltable ink 10C melt-transferred on the intermediate transfer member 100 is 3 × 10 ⁻⁸ kg, and the heat transfer is performed on the intermediate transfer member 100. Assuming that the melt transfer temperature at the time of performing is 125 ° C. and the room temperature is 20 ° C.,
If the amount of heat Q3 given when the hot-melt ink 10C is melt-transferred to the intermediate transfer member 100 is in the range of 6.3 to 18.9 mJ, the cyan ink image 200C is first transferred onto the intermediate transfer member 100. Yellow ink image 2 being formed
00Y and the magenta ink image 200M can be transferred and formed on the intermediate transfer member 100 without being disturbed by re-melting.

Further, as a third embodiment, the hot-melt inks 10Y, 10M, and 10C of the respective colors were transferred to the intermediate transfer member 100.
The case where the melt transfer temperature at the time of melt transfer on the top is changed will be described.

Here, the main component of the hot-melt ink is
Of the coloring materials, wax, and resin, materials used for wax,
For example, changing the molecular weight of the paraffin wax can change the melting temperature of the hot-melt ink.

First, a yellow ink image 200Y is formed on the intermediate transfer member 100. At that time, the hot-melt ink 10
The heat capacity of Y is 2 kJ / kg · K, and the amount of the heat-meltable ink 10Y melt-transferred onto the intermediate transfer member 100 is 5 × 10 ^−8.
Assuming that the melt transfer temperature at the time of melt transfer on the intermediate transfer member 100 is 125 ° C. and the room temperature is 20 ° C., the amount of heat given when the heat-meltable ink 10Y is melt-transferred to the intermediate transfer member 100 is 10. If 5 mJ, the intermediate transfer member 100
Is formed with a yellow ink image 200Y corresponding to the image signal.

Thereafter, a magenta ink image 200M is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y. At this time, the heat capacity of the hot-melt ink 10M was 2 k.
J / kg · K, the amount of the hot-melt ink 10M melt-transferred on the intermediate transfer member 100 is 5 × 10 ⁻⁸ kg, and the melt transfer temperature at the time of melt-transfer on the intermediate transfer member 100 is 115.
When the temperature and room temperature are set to 20 ° C., the amount of heat Q2 given when the hot-melt ink 10M is melt-transferred to the intermediate transfer member 100.
Is within the range of 9.5 to 10.5 mJ, the magenta ink image 200 </ b> M is disturbed by re-melting the yellow ink image 200 </ b> Y previously formed on the intermediate transfer member 100 without disturbing the intermediate transfer member. 100 can be formed by transfer.

Finally, a cyan ink image 200C is formed on the intermediate transfer member 100 so as to overlap the yellow ink image 200Y and the magenta ink image 200M. At this time, the heat capacity of the heat-meltable ink 10C is 2 kJ / kg · K, the amount of the heat-meltable ink 10C melt-transferred on the intermediate transfer member 100 is 5 × 10 ⁻⁸ kg, and the heat transfer is performed on the intermediate transfer member 100. Assuming that the melt transfer temperature at the time of performing is 105 ° C. and the room temperature is 20 ° C.,
If the amount of heat Q3 given when the heat-meltable ink 10C is melt-transferred to the intermediate transfer member 100 is in the range of 8.5 to 19 mJ, the cyan ink image 200C is first transferred and formed on the intermediate transfer member 100. Yellow ink image 200
The Y and magenta ink images 200M can be transferred and formed on the intermediate transfer member 100 without re-melting and disturbing.

As in the first embodiment described above, in order to set the melt transfer temperature of each color ink 10Y, 10M, 10C, for example, yellow ink 10Y, magenta ink 10M, cyan ink The molecular weight of the wax may be increased in the order of 10C.

In the first to third embodiments described in detail above,
The method of changing only one of the heat capacity of the heat-meltable ink, the amount of the ink melt-transferred on the intermediate transfer member, and the melt transfer temperature has been described as an example. It has the same effect as the example.

[0080]

As is apparent from the above description, in the image forming method according to the first aspect, the amount of heat applied when an ink image to be transferred later is superimposed on the previously transferred ink image is transferred. Is smaller than the amount of heat for remelting the previously transferred ink image, so that the ink images transferred earlier can be overlapped without disturbing the ink image. Also, there is an effect that the thermal transfer time of each ink image can be easily set to the same time.

In the image forming apparatus according to the present invention, the amount of heat applied when transferring the ink image to be transferred later to the intermediate transfer member is smaller than the amount of heat for re-melting the previously transferred ink image. Therefore, the ink image can be superimposed on the intermediate transfer member without disturbing the previously transferred ink image.
Thereafter, the thermal transfer unit melt-transfers the desired ink image formed by superimposing the plurality of ink images formed on the intermediate transfer body onto the recording medium, so that a clear image is formed on the recording medium. Can be. Further, since the ink holding means is always replenished with ink, unlike the conventional thermal transfer method using an ink ribbon, the untransferred ink is not wasted, and an image can be formed at a low running cost. is there. In addition, there is an effect that the thermal transfer time of each ink image to the intermediate transfer member can be easily set to the same time.

Further, in the image forming apparatus according to the third aspect, in addition to the effect of the second aspect, since the ink holding means is made of ceramic, the heat resistance is high, and the ink holding means is damaged even when repeatedly heated by the heat recording means. It has no super long life.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram of an embodiment of the present invention.

FIG. 2 is a diagram illustrating a state of an ink image that is melt-transferred on an intermediate transfer member according to an embodiment of the present invention.

[Explanation of symbols]

 10Y, 10M, 10C Heat-meltable ink 20Y, 20M, 20C Heater 30Y, 30M, 30C Ink holder 40 Recording medium 50Y, 50M, 50C Thermal head 100 Intermediate transfer member

Claims (3)

[Claims] 1. An image forming method for forming an image by melt-transferring a plurality of types of hot-melt inks, wherein the heat capacity of the n-th (n = 1, 2,..., I) -th hot-melt ink to be melt-transferred Where C _n , the amount of the heat-meltable ink that is melt-transferred n-th is W _n , the temperature at which the heat-melt ink that is melt-transferred n-th is melt-transferred is T _n , and the room temperature is _Tr , heat Q _n are, Equation 1] at the time of transferring melting the hot-melt ink An image forming method characterized by satisfying the following. 2. A plurality of solid-state heat-meltable inks; a heat-melting unit configured to independently heat-melt the plurality of types of heat-meltable inks for each type; An ink holding unit that independently absorbs and holds the plurality of types of heat-meltable inks heated and melted for each type, and heats the ink holding unit holding the ink for each type of ink, and the heated portion A plurality of ink images formed on the intermediate transfer member are superimposed by heating and recording means for melting the ink and sequentially transferring the ink images onto the intermediate transfer member so as to form a desired ink image; Thermal transfer means for melt-transferring the formed desired ink image onto a recording medium, wherein the heat recording means comprises an n (n = 1, 2,..., I) -th heat-meltable ink Heat capacity is C _n , nth When the amount of the heat-meltable ink to be melt-transferred is W _n , the temperature at which the n-th heat-meltable ink to be melt-transferred is melt-transferred is T _n , and the room temperature is _Tr , the n-th heat-meltable ink is melted. the amount of heat Q _n at the time of transfer, [number 1] An image forming apparatus configured to satisfy the following. 3. The image forming apparatus according to claim 2, wherein the ink holding unit is formed of a fibrous ceramic in a paper shape.