JP2000211116A - Ink drying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink drying apparatus preventing the scorching of a recording medium caused by overheating and capable of realizing the proper energy charging density to the recording medium without damaging drying properties. SOLUTION: An ink drying apparatus is equipped with three almost columnar halogen lamps 12a, 12b provided so that the longitudinal direction thereof is set along the direction almost vertical to the feed direction of recording paper and parallelly arranged so as to provide a predetermined distance interval, the reflector 14 provided so as to surround these three halogen lamps 12a, 12b, the almost rectangular platen provided to the position opposed to the reflector 14 and three halogen lamps 12a, 12b, an inlet duct 18 discharging the open air introduced from an inlet fan 16a to the upstream side in the feed direction of the drying region from a discharge port 18a through the rear surface side of the reflector 14 and a discharge duct 19 introducing the hot air from the upstream side in the feed direction of the drying region from an inlet port to discharge the same to the outside by a discharge fan 16b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink drying apparatus, and more particularly to an ink drying apparatus used for an ink jet recording apparatus.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 7-1749 discloses a part of a medium provided in a printing area in order to print a high quality color image on plain paper and obtain a color inkjet printer having a simple structure. There has been proposed a printer having a print heater means for heating the ink to speed up drying of the ink applied to the medium.

[0003] The heater means has a radiant heat source for generating heat energy and means for directing the radiant heat energy to a part of a second surface (back surface) of a print medium provided in a print area. And drying the ink droplets formed on the first surface (front surface) of the recording medium by the print head from the second surface (back surface) side.

Japanese Patent Application Laid-Open No. Hei 8-224871 discloses that a recording paper is heated by radiant heat of a heating element and, at the same time, outside air is sucked into an intake duct and heated by the heating element to generate warm air. There is disclosed a recording liquid fixing device that blows air onto recording paper to heat it. This recording liquid fixing device heats the recording paper using both the radiant heat of the heating element and the hot air, thereby effectively utilizing the heat energy of the heating element and fixing the ink on the recording paper uniformly in a short time. It is.

In recent years, in order to obtain high character image quality, there is a tendency to use slow dry black ink which is hard to dry but can obtain high character image quality. For this reason, a conventional ink jet printer uses a heat source having high thermal energy so that the ink can be surely dried even in a short conveyance path using one heat source. Such an ink jet printer is configured to flow air over the recording paper not only to realize reliable drying, but also to prevent scorching of the recording paper due to the use of a heat source of high thermal energy.

[0006]

However, the distribution of the thermal energy input density to a recording medium such as recording paper by one heat source is Gaussian distribution which is highest immediately below the heat source and gradually lowers as the distance from the heat source increases. Distribution. Therefore, when a heat source that radiates one high heat energy is used, if a heat source having a heat energy input density at which the ink is surely dried is selected, the heat energy input density is locally increased in a region directly below the heat source. In some cases, the recording medium may be overheated in the area immediately below the heat source and burnt.

[0007] In particular, this scorching occurs when the recording medium is left in a drying area for a preset drying time, for example, until the conveyance of the recording medium is stopped for some reason, and the recording medium is recovered. It is easy to occur and becomes a problem.

As described above, the present invention prevents the recording medium from being scorched by overheating, and does not impair the drying property.
It is an object of the present invention to provide an ink drying device that can realize an appropriate energy input density for a recording medium.

[0009]

In order to achieve the above object, the ink drying apparatus according to the first aspect of the present invention applies heat energy to a recording medium on which ink has been applied substantially uniformly within a predetermined drying area. It has a plurality of heat radiation members arranged as described above.

That is, according to the first aspect of the present invention, attention is paid to the fact that the amount of heat energy required for drying the ink is a certain amount, and a plurality of heat radiating members are used to make the recording medium substantially uniform. The ink is dried by applying heat energy to the ink.

Thus, the heat energy required for each heat radiation member can be made smaller than the heat energy required for drying the ink by one heat radiation member, and the partial concentration of the heat energy can be reduced. Since it can be avoided, scorching of the recording medium due to overheating can be prevented without impairing the drying property.

Therefore, it is possible to dry the ink on the recording medium by setting the drying area longer and to spend more time than in the prior art, and there is an advantage that the degree of freedom in designing the ink drying apparatus is improved.

The arrangement of the plurality of heat radiating members is as follows.
A plurality of substantially spherical shapes and heat radiating members are arranged in a two-dimensional array at an arrangement interval at which a combined heat energy amount obtained by combining the heat energy amounts radiated by the individual heat radiating members becomes a predetermined constant value. Alternatively, a plurality of substantially circular heat radiating members having different diameters may be provided concentrically. When a plurality of substantially circular heat radiating members having different diameters are provided concentrically,
Each diameter is determined so that the combined amount of heat energy obtained by combining the amounts of heat energy radiated by the individual heat radiation members becomes a predetermined constant value.

In addition, as described in claim 2, a plurality of substantially cylindrical heat radiating members are combined with the heat radiated by the individual heat radiating members so that the combined heat energy is a predetermined value. May be provided in such a direction that the longitudinal direction is substantially perpendicular to the conveying direction of the recording medium. Note that the predetermined constant value is a thermal energy value determined by a balance between the amount of thermal energy required to dry the ink, the length of the dry area, and the time during which the recording medium is placed in the dry area. It is.

Further, the heat radiation member may be constituted by a near-infrared lamp such as a halogen lamp, for example. Because near-infrared light has the same or higher absorption capacity for water than paper. for that reason,
For example, when a recording medium is paper and a near-infrared lamp is used as a heat radiation member for drying an ink jet recording apparatus that often uses an ink in which a pigment is dispersed in water,
Since the thermal energy is selectively absorbed by the ink rather than the recording medium, the ink dries efficiently.

Further, in the ink drying apparatus according to any one of claims 1 to 3, the ink drying apparatus is provided so as to surround the plurality of heat radiating members. A first heat reflecting member that reflects heat from the heat radiating member; and a first heat reflecting member that is provided at a position facing the first heat reflecting member. And a second heat reflection member that reflects incident heat toward the transport path.

That is, by reflecting the heat from the plurality of heat radiating members by the first heat reflecting member, the heat energy from the first heat reflecting member can be efficiently used, and the second heat reflecting member can be efficiently used. The reflection member reflects the incident heat toward the transport path, thereby preventing overheating of the second heat reflection member and reusing the irradiation energy.

According to a fourth aspect of the present invention, in the ink drying apparatus according to the fifth aspect, outside air is introduced from the back side of the first heat reflecting member to the upstream side in the transport direction of the transport path. It is preferable to include an introduction duct portion for guiding, and a discharge duct portion for discharging air from the upstream side of the transport path to the outside from the downstream side of the transport path.

That is, since the first heat reflecting member, which has been stored by the heat energy from the plurality of heat radiating members, is cooled by the introduced outside air, the introduced outside air is warmed and turned into warm air before being sent to the drying area. It will be dried.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. In this embodiment, the ink drying apparatus of the present invention is applied to an ink jet recording apparatus.

As shown in FIGS. 1 and 2, this ink jet recording apparatus is roughly divided into a conveying roller group 20 for conveying a recording paper 32 as a recording medium from an introduction side to an exit side.
Y (yellow), M (magenta), C (cyan), B
A head unit 30 including an ink tank (not shown) storing four color inks (black) and recording heads (not shown) provided for each color, corresponding to the ink drying apparatus of the present invention. It comprises a dryer unit 10 and a pair of transport rollers 22 provided on the discharge side of the recording paper 32.

The transport roller group 20 is composed of a plurality of rollers arranged in parallel along the transport direction.
From the head unit 30 toward the dryer unit 10. The transport roller pair 22 includes a pair of rollers, and discharges the recording paper 32 dried by the dryer unit 10 described below to the outside.

The head unit 30 is configured to be movable along a guide (not shown) provided along a direction substantially perpendicular to the direction in which the recording paper 32 is conveyed, and while moving along the guide. Ink of a color corresponding to the image information is ejected on the surface of the introduced recording paper 32.

The dryer unit 10 is provided at a stage subsequent to the head unit 30 and introduces a recording paper 32 onto which a plurality of colors of ink have been sprayed, and applies heat energy to the recording paper 32 in a drying area formed therein. And dry.

The dryer unit 10 includes two column-shaped halogen lamps 12a and 12b, the first of the present invention.
A reflector 14 as a heat reflecting member, a platen 17 as a second heat reflecting member of the present invention, an inlet duct 18 corresponding to the inlet duct portion of the present invention, and a discharge duct 19 corresponding to the outlet duct portion of the present invention. Have been.

The halogen lamps 12a and 12b are respectively provided above the path for transporting the introduced recording paper along the direction in which the longitudinal direction is substantially perpendicular to the transport direction of the recording paper 32.
They are arranged in parallel at a predetermined distance from each other.

The individual halogen lamps 12a, 12a
b radiate heat energy in a direction of 360 degrees around the central axis, a reflector 14 is provided so as to surround these two halogen lamps 12a and 12b, and the reflector 14 is provided with two halogen lamps 12a and 12b.
Of the thermal energy radiated by a and 12b, the thermal energy radiated in a direction not toward the path for transporting the recording paper 32 is reflected toward the path for transporting the recording paper 32, and the recording paper 32 is transported. A dry area is formed on the path to be dried.

The predetermined distance interval is defined as the recording paper 3
2, two halogen lamps 12a, 1
2b is a heat energy amount suitable for drying the ink and is an interval that is substantially uniform in the drying area.
Assuming that the combined heat energy of the combined heat energy of the two halogen lamps 12a and 12b and the heat energy reflected by the reflector 14 is a heat energy appropriate for drying the ink, and that the interval becomes substantially uniform in the drying area. Good. Therefore, the predetermined distance interval can be appropriately changed according to the amount of heat energy emitted by the halogen lamp, the number of halogen lamps, the reflectance of the reflector 14, and the like.

The drying area is provided with a substantially rectangular platen 17 over the entire drying area at a position facing the reflector 14 and the two halogen lamps 12a and 12b. Is reflected back to the dry area. This allows
Prevents overheating of the platen while reusing the irradiation energy. Therefore, heat energy is more efficiently applied to the recording paper 32.

Further, a discharge port 18a of the introduction duct 18 is arranged on the upstream side in the transport direction of the drying area. The introduction duct 18 includes an introduction fan 16a for introducing outside air,
The outside air introduced by the introduction fan 16a is
Is discharged from the discharge port 18a to the upstream side in the transport direction of the drying area through the back side of the substrate.

The introduction duct 18 directs outside air to the reflector 1
By discharging the air through the back surface side of 4 and upstream of the drying area in the transport direction, the introduced outside air cools the reflector 14 stored by the heat energy of the two halogen lamps 12a and 12b and simultaneously warms the introduced outside air. Since the air is sent to the drying area after being heated, it is possible to prevent the reflector from accumulating heat and consequently raising the temperature, and to increase the drying efficiency of the ink.

In addition, since the reflector 14 can be cooled without directly cooling the halogen lamps 12a and 12b, which are heat radiation members, by the outside air, the halogen lamps 12a and 12b are damaged by rapid cooling, and the ink drying efficiency is reduced due to a decrease in temperature. It is possible to prevent a decrease in the temperature, and also to prevent the heat storage of the entire drying apparatus, thereby eliminating the possibility of the user being burned during maintenance or the like.

Further, an inlet of the discharge duct 19 is arranged downstream of the drying area in the transport direction. Discharge duct 19
Is provided with a discharge fan 16b that discharges outside air to the outside, and introduces warm air from the upstream side in the transport direction of the drying area through the inlet 19a, and discharges the outside by the discharge fan 16b. Thus, it is possible to prevent hot air from leaking from the paper introduction and discharge ports of the drying device, and to prevent overheating of the entire recording device.

Therefore, a flow of warm air (see the arrow in FIG. 2) from the upstream side in the transport direction of the recording paper 32 to the downstream side in the transport direction is formed on the transport path of the recording paper 32 in the drying area, and the drying is performed. The recording paper 32 introduced into the area is 2
In addition to the drying by the heat energy from the two halogen lamps 12a and 12b, the drying is also performed by the flow of the warm air.

FIG. 3 shows color temperatures of 1700K to 18K.
The result of evaluating the paper scorch by the dryer unit having the configuration of the present embodiment using a halogen lamp of 00K and a wavelength of 3 μm is shown. Here, the dryer unit 1
100 W inside the reflector 14 of 50 mm width provided inside
The scorch was evaluated for each of the case where two halogen lamps were arranged in parallel along the paper transport direction and the case where one 200 W halogen lamp was arranged.

The ordinate in FIG. 3 is the burn value, and the burn value described here is a value obtained by parameterizing the density measured under the following conditions with the density of black as 1. Note that the horizontal axis is the input energy (W).

That is, the burning value is 10 mm × 10 mm (240 × 240 p at 600 dpi) by black ink.
ixels, equivalent to 34 pl) recording paper 3 printed with solid patches
After leaving the halogen lamp, the introduction fan 16a and the discharge fan 16b in the on state for 5 minutes with the halogen lamp, the introduction fan 16a and the discharge fan 16b turned on, and leaving the halogen lamp, the introduction fan 16a and the discharge fan 16b in the off state for 5 minutes Then, after taking out from the dry area, measuring the density on the back side of the solid patch printing position, the scoring value measured when the recording paper 32 on which the solid patch was not printed was similarly processed was subtracted as an offset. The density is parameterized by setting the density of black to 1.

This condition is based on the assumption that burning occurs due to overheating when an abnormality such as a paper jam occurs. The scorching value is less than 0.4 when no scorching occurs, and when 0.4 or more, scorching occurs.

FIG. 3 shows that even with the same input energy, scorching is more likely to occur when one 200 W halogen lamp is arranged than when two 100 W halogen lamps are arranged in parallel along the paper transport direction. You can see that.

FIG. 4 shows the result of verifying whether the drying property differs depending on the number of halogen lamps. The horizontal axis indicates the time (sequence) during which the recording paper 32 was placed in the drying area.
c) The vertical axis indicates the drying level (Drying Grade). In addition, as for the drying level (Drying Grade), 0 represents complete drying, 1-3 represents a slightly undried portion, and 4 to 6 represent undried, and the undried portion increases as the numerical value increases. . As is clear from FIG. 4, if the amount of heat energy is adjusted to be the same, the drying property does not change even if the number of halogen lamps is different.

FIG. 5 shows an example of the relationship between the lamp interval and the applied energy distribution when two halogen lamps are used. The vertical axis is the thermal energy (W) reaching the drying area, and the horizontal axis is the position (mm) in the drying area with the uppermost stream position in the transport direction of the drying area as a reference (that is, 0 mm).

The solid line 50 indicates that the total input energy is 800
The thermal energy (W) distribution when one halogen lamp of W is arranged at the center is shown. The dotted line 52 indicates the thermal energy when two halogen lamps having a total input energy of 400 W are arranged at 120 mm intervals. The dashed line 54 indicates the thermal energy (W) distribution when two halogen lamps having a total input energy of 423 W are arranged at 120 mm intervals.

As is clear from FIG. 5, when one halogen lamp is arranged at the center, the distribution of heat energy (W) becomes a Gaussian distribution, and 5.6 at the center of the dry area.
When the two halogen lamps are arranged at intervals of 120 mm, the heat energy (W) increases to about W.
Is flattened, and is maintained at about 2 W to 3 W in a region between 71 mm and 171 mm. Similarly, when two halogen lamps having a total input energy of 423 W are arranged at an interval of 120 mm, the same is maintained at about 2 W to 3 W in a region between 71 mm and 171 mm.

That is, in this case, by arranging the two halogen lamps at a distance of about 120 mm, a substantially uniform heat energy can be given to the recording paper.
In addition, since high heat energy is not applied to the recording paper, it can be seen that the recording paper can be prevented from being overheated and scorched during drying.

Therefore, it is also possible to provide a relatively long drying area and apply heat energy to the recording paper for a long time to dry the recording paper. Since it is not applied to the paper, the occurrence of scorching of the recording paper can be suppressed.

The above conditions are merely examples, and the present invention is not limited to these numerical values. That is, the number of halogen lamps, such that the amount of heat energy applied to the recording paper in the entire dry area is the amount of heat energy required for drying, and so that substantially uniform heat energy is applied to the recording paper, The present invention can be realized by appropriately adjusting the arrangement interval of the halogen lamps and the magnitude of the input energy amount.

In this embodiment, a halogen lamp is used as the heat radiation member. Halogen lamps are near-infrared lamps. As shown in FIG. 6, in the near-infrared region, the energy absorption of water and paper is almost the same or water is larger. Therefore, when a halogen lamp is used as a heat radiating member for drying of an ink jet recording apparatus which often uses an ink in which a pigment is dispersed in water, the recording paper 3
2, overheating can be suppressed, and sufficient thermal energy can be efficiently given to the ink on the recording paper 32. Further, since the absorption amount of the near infrared ray varies depending on the color of the object, there is an advantage that the thermal energy is selectively absorbed by the ink on the recording paper 32 and efficient drying can be performed.

FIG. 7 shows the result of evaluating the drying property when the ink is dried by the near-infrared heater and the result of evaluating the drying property when the ink is dried by the far-infrared heater.

In FIG. 7, the horizontal axis represents the time (sec) during which the recording paper 32 was placed in the drying area, and the vertical axis represents the drying level (D).
rying Grade). Near infrared heater, color temperature 1700K-1800K, wavelength 3μm or less, 400W
And a far-infrared heater with a wavelength of 6 to 15 μm.
m, 300 W were used. In addition, 10 mm x 10 mm (240 x 2 at 600 dpi)
The recording paper 32 on which a solid patch of 40 pixels and 34 pl is printed is a drying target, and the drying area is different for each of the case where the ink is dried by the near infrared heater and the case where the ink is dried by the far infrared heater. The drying property was examined in a state where air was circulated inside and a state where air introduced outside air was circulated.

As described above, the drying level (Drying Gra
de) indicates that the smaller the numerical value is, the more dry it is. Therefore, as is clear from FIG. 7, even if the input energy of the near infrared ray is larger than that of the near infrared ray, the near infrared ray has a shorter time than the far infrared ray. It means that the sample was dried (that is, the drying property was good).

The recording paper 3 in each of the case where the far-infrared heater is used and the case where the near-infrared heater is used are described.
The occurrence of scorch in No. 2 was examined. Here, the following two experiments were performed for the case where the far-infrared heater was used and the case where the near-infrared heater was used, and the burnt state of each recording paper was examined. A far infrared heater having a wavelength of 6 to 15 μm and 300 W is used, and a near infrared heater having a color temperature of 1700 K to 1800 K and a wavelength of 3 W
The one having a power of 400 W or less was used. Recording paper 3
As No. 2, 4024 paper (plain paper for copying) was used.

First, with the heater turned on, the introduction fan 16a and the discharge fan 16b are turned on to introduce outside air, and the 4024 paper is left in the drying area for 5 minutes.
The heater, the introduction fan 16a and the discharge fan 16b were turned off and left in the drying area for 5 minutes, and then taken out of the drying area and the density of 4024 paper was measured. The result obtained by this experiment is defined as the result of the open system. This experiment was performed several times while changing the set voltage of the fan.

Further, a fan is provided inside the drying device, and 4024 paper is left in the drying region for 5 minutes while circulating the air inside the drying region.
a and the discharge fan 16b are turned off and left in the drying area for 5 minutes.
The density of the four papers was measured. The result obtained by this experiment is defined as the result of the circulation system. This experiment was also performed several times while changing the set voltage of the fan. Each of these open system and circulating system conditions is based on the assumption of burning due to overheating when an abnormality such as a paper jam occurs, as described above.

Table 1 shows the results of the above two experiments when the far-infrared heater was used, and Table 2 shows the results of the two experiments when the near-infrared heater was used.

[0055]

[Table 1]

[0056]

[Table 2]

In Tables 1 and 2, the range from no scorch to slight discoloration is within the allowable range, and the discoloration is clearly outside the allowable range. As is evident from Tables 1 and 2, it can be seen that the near-infrared heater and the far-infrared heater do not significantly differ in the state of scorch even though the near-infrared heater has a larger input energy. Therefore, when using a near-infrared heater, while maintaining good drying properties,
It can be said that generation of scorched paper can be suppressed.

FIG. 8 is a graph showing the spectral distribution of black body radiation energy for a plurality of types of color temperatures. As is clear from this graph, a near-infrared lamp that emits near-infrared light having a short wavelength has higher energy efficiency than a far-infrared lamp that emits far-infrared light having a long center wavelength.

[0059]

As described above, according to the present invention, an ink drying apparatus capable of preventing a recording medium from being scorched due to overheating and realizing a proper energy input density to the recording medium without impairing the drying property. Is obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view illustrating a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is a graph showing a result of evaluating the scorching of paper according to the number of halogen lamps in the dryer unit having the configuration shown in FIG. 1;

FIG. 4 is a graph showing the result of verifying whether the drying property differs depending on the number of halogen lamps in the dryer unit having the configuration shown in FIG.

FIG. 5 is a graph showing a relationship between a lamp interval and an input energy distribution when two halogen lamps are used in the dryer unit having the configuration shown in FIG.

6A is a graph showing a wavelength absorption curve of water, and FIG. 6B is a graph showing a wavelength absorption curve of paper.

FIG. 7 is a graph showing the evaluation results of the drying property when the ink is dried by the near-infrared heater and the drying property when the ink is dried by the far-infrared heater.

FIG. 8 is a graph showing a spectral distribution of blackbody radiation energy with respect to a plurality of types of color temperatures.

[Explanation of symbols]

 Reference Signs List 10 dryer unit 12a halogen lamp 14 reflector 16a introduction fan 16b discharge fan 17 platen 18 introduction duct 19 discharge duct 20 transport roller group 22 transport roller pair 30 head unit 32 recording paper

Continued on the front page (72) Inventor Keisuke Yasuda 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Jun Isozaki 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. 72) Inventor Jun Takamura 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Yumiko Namba 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. F-term (reference) 2C056 HA46 HA47

Claims (5)

[Claims] 1. An ink drying apparatus having a plurality of heat radiating members arranged so as to apply heat energy substantially uniformly to a recording medium with ink attached thereto in a predetermined drying area. 2. The heat radiation member has a substantially cylindrical shape, and the plurality of heat radiation members have a predetermined constant value of a combined heat energy amount obtained by combining heat energy amounts radiated by the individual heat radiation members. 2. The ink drying apparatus according to claim 1, wherein the ink drying apparatuses are arranged in parallel at a certain interval so that a longitudinal direction thereof is substantially perpendicular to a conveying direction of the recording medium. 3. The ink drying device according to claim 1, wherein the heat radiation member is a near infrared lamp. 4. A first heat reflecting member provided so as to surround the plurality of heat radiating members and reflecting heat from the plurality of heat radiating members, and a first heat reflecting member facing the first heat reflecting member. A second heat reflection member that forms a conveyance path of the recording medium between the first heat reflection member and the first heat reflection member, and reflects incident heat toward the conveyance path. The ink drying device according to claim 1. 5. An introduction duct section for introducing outside air and guiding the air from the back side of the first heat reflection member to an upstream side in the transport direction of the transport path, and directs air from an upstream side of the transport path to the transport path. The ink drying device according to any one of claims 1 to 4, further comprising: a discharge duct configured to discharge from a downstream side to the outside.